actually test always_zero hasher

different widths must make values compare not equal otherwise interning
will e.g. substitute a 0x0_u8 for a 0x0_u2

.forgejo/workflows/deps.yml

@@ -12,10 +12,10 @@ jobs:
     outputs:
       cache-primary-key: ${{ steps.restore-deps.outputs.cache-primary-key }}
     steps:
-      - uses: https://code.forgejo.org/actions/checkout@v3
+      - uses: https://git.libre-chip.org/mirrors/checkout@v3
         with:
           fetch-depth: 0
-      - uses: https://code.forgejo.org/actions/cache/restore@v3
+      - uses: https://git.libre-chip.org/mirrors/cache/restore@v3
         id: restore-deps
         with:
           path: deps
@@ -58,19 +58,19 @@ jobs:
       - name: Get SymbiYosys
         if: steps.restore-deps.outputs.cache-hit != 'true'
         run: |
-          git clone --depth=1 --branch=yosys-0.45 https://github.com/YosysHQ/sby.git deps/sby
+          git clone --depth=1 --branch=yosys-0.45 https://git.libre-chip.org/mirrors/sby deps/sby
       - name: Build Z3
         if: steps.restore-deps.outputs.cache-hit != 'true'
         run: |
-          git clone --depth=1 --recursive --branch=z3-4.13.3 https://github.com/Z3Prover/z3.git deps/z3
+          git clone --depth=1 --recursive --branch=z3-4.13.3 https://git.libre-chip.org/mirrors/z3 deps/z3
           (cd deps/z3; PYTHON=python3 ./configure --prefix=/usr/local)
           make -C deps/z3/build -j"$(nproc)"
       - name: Build Yosys
         if: steps.restore-deps.outputs.cache-hit != 'true'
         run: |
-          git clone --depth=1 --recursive --branch=0.45 https://github.com/YosysHQ/yosys.git deps/yosys
+          git clone --depth=1 --recursive --branch=0.45 https://git.libre-chip.org/mirrors/yosys deps/yosys
           make -C deps/yosys -j"$(nproc)"
-      - uses: https://code.forgejo.org/actions/cache/save@v3
+      - uses: https://git.libre-chip.org/mirrors/cache/save@v3
         if: steps.restore-deps.outputs.cache-hit != 'true'
         with:
           path: deps

.forgejo/workflows/test.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: debian-12
     needs: deps
     steps:
-      - uses: https://code.forgejo.org/actions/checkout@v3
+      - uses: https://git.libre-chip.org/mirrors/checkout@v3
         with:
           fetch-depth: 0
       - run: |
@@ -41,7 +41,7 @@ jobs:
           curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain 1.82.0
           source "$HOME/.cargo/env"
           echo "$PATH" >> "$GITHUB_PATH"
-      - uses: https://code.forgejo.org/actions/cache/restore@v3
+      - uses: https://git.libre-chip.org/mirrors/cache/restore@v3
         with:
           path: deps
           key: ${{ needs.deps.outputs.cache-primary-key }}
@@ -52,10 +52,11 @@ jobs:
           make -C deps/yosys install
           export PATH="$(realpath deps/firtool/bin):$PATH"
           echo "$PATH" >> "$GITHUB_PATH"
-      - uses: https://github.com/Swatinem/rust-cache@v2
+      - uses: https://git.libre-chip.org/mirrors/rust-cache@v2
         with:
           save-if: ${{ github.ref == 'refs/heads/master' }}
       - run: cargo test
       - run: cargo build --tests --features=unstable-doc
       - run: cargo test --doc --features=unstable-doc
       - run: cargo doc --features=unstable-doc
+      - run: FAYALITE_TEST_HASHER=always_zero cargo test --test=module --features=unstable-doc,unstable-test-hasher

Cargo.lock

@@ -2,18 +2,6 @@
 # It is not intended for manual editing.
 version = 3
 
-[[package]]
-name = "ahash"
-version = "0.8.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "77c3a9648d43b9cd48db467b3f87fdd6e146bcc88ab0180006cef2179fe11d01"
-dependencies = [
- "cfg-if",
- "once_cell",
- "version_check",
- "zerocopy",
-]
-
 [[package]]
 name = "allocator-api2"
 version = "0.2.16"
@@ -365,6 +353,12 @@ version = "0.5.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1d674e81391d1e1ab681a28d99df07927c6d4aa5b027d7da16ba32d1d21ecd99"
 
+[[package]]
+name = "foldhash"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9c4f5dac5e15c24eb999c26181a6ca40b39fe946cbe4c263c7209467bc83af2"
+
 [[package]]
 name = "funty"
 version = "2.0.0"
@@ -400,12 +394,13 @@ checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
 
 [[package]]
 name = "hashbrown"
-version = "0.14.3"
+version = "0.15.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "290f1a1d9242c78d09ce40a5e87e7554ee637af1351968159f4952f028f75604"
+checksum = "bf151400ff0baff5465007dd2f3e717f3fe502074ca563069ce3a6629d07b289"
 dependencies = [
- "ahash",
  "allocator-api2",
+ "equivalent",
+ "foldhash",
 ]
 
 [[package]]
@@ -431,9 +426,9 @@ checksum = "ce23b50ad8242c51a442f3ff322d56b02f08852c77e4c0b4d3fd684abc89c683"
 
 [[package]]
 name = "indexmap"
-version = "2.5.0"
+version = "2.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "68b900aa2f7301e21c36462b170ee99994de34dff39a4a6a528e80e7376d07e5"
+checksum = "cea70ddb795996207ad57735b50c5982d8844f38ba9ee5f1aedcfb708a2aa11e"
 dependencies = [
  "equivalent",
  "hashbrown",
@@ -524,11 +519,14 @@ dependencies = [
 
 [[package]]
 name = "petgraph"
-version = "0.6.5"
-source = "git+https://github.com/programmerjake/petgraph.git?rev=258ea8071209a924b73fe96f9f87a3b7b45cbc9f#258ea8071209a924b73fe96f9f87a3b7b45cbc9f"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a98c6720655620a521dcc722d0ad66cd8afd5d86e34a89ef691c50b7b24de06"
 dependencies = [
  "fixedbitset",
+ "hashbrown",
  "indexmap",
+ "serde",
 ]
 
 [[package]]
@@ -893,23 +891,3 @@ checksum = "05f360fc0b24296329c78fda852a1e9ae82de9cf7b27dae4b7f62f118f77b9ed"
 dependencies = [
  "tap",
 ]
-
-[[package]]
-name = "zerocopy"
-version = "0.7.32"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "74d4d3961e53fa4c9a25a8637fc2bfaf2595b3d3ae34875568a5cf64787716be"
-dependencies = [
- "zerocopy-derive",
-]
-
-[[package]]
-name = "zerocopy-derive"
-version = "0.7.32"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ce1b18ccd8e73a9321186f97e46f9f04b778851177567b1975109d26a08d2a6"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]

Cargo.toml

@@ -23,14 +23,13 @@ blake3 = { version = "1.5.4", features = ["serde"] }
 clap = { version = "4.5.9", features = ["derive", "env", "string"] }
 ctor = "0.2.8"
 eyre = "0.6.12"
-hashbrown = "0.14.3"
+hashbrown = "0.15.2"
 indexmap = { version = "2.5.0", features = ["serde"] }
 jobslot = "0.2.19"
 num-bigint = "0.4.6"
 num-traits = "0.2.16"
 os_pipe = "1.2.1"
-# TODO: switch back to crates.io once petgraph accepts PR #684 and releases a new version
-petgraph = { git = "https://github.com/programmerjake/petgraph.git", rev = "258ea8071209a924b73fe96f9f87a3b7b45cbc9f" }
+petgraph = "0.8.1"
 prettyplease = "0.2.20"
 proc-macro2 = "1.0.83"
 quote = "1.0.36"

crates/fayalite-proc-macros-impl/src/fold.rs

@@ -220,6 +220,7 @@ forward_fold!(syn::ExprArray => fold_expr_array);
 forward_fold!(syn::ExprCall => fold_expr_call);
 forward_fold!(syn::ExprIf => fold_expr_if);
 forward_fold!(syn::ExprMatch => fold_expr_match);
+forward_fold!(syn::ExprMethodCall => fold_expr_method_call);
 forward_fold!(syn::ExprPath => fold_expr_path);
 forward_fold!(syn::ExprRepeat => fold_expr_repeat);
 forward_fold!(syn::ExprStruct => fold_expr_struct);

crates/fayalite-proc-macros-impl/src/hdl_bundle.rs

@@ -30,7 +30,9 @@ pub(crate) struct ParsedBundle {
     pub(crate) field_flips: Vec<Option<HdlAttr<kw::flip, kw::hdl>>>,
     pub(crate) mask_type_ident: Ident,
     pub(crate) mask_type_match_variant_ident: Ident,
+    pub(crate) mask_type_sim_value_ident: Ident,
     pub(crate) match_variant_ident: Ident,
+    pub(crate) sim_value_ident: Ident,
     pub(crate) builder_ident: Ident,
     pub(crate) mask_type_builder_ident: Ident,
 }
@@ -83,6 +85,7 @@ impl ParsedBundle {
             custom_bounds,
             no_static: _,
             no_runtime_generics: _,
+            cmp_eq: _,
         } = options.body;
         let mut fields = match fields {
             syn::Fields::Named(fields) => fields,
@@ -124,7 +127,9 @@ impl ParsedBundle {
             field_flips,
             mask_type_ident: format_ident!("__{}__MaskType", ident),
             mask_type_match_variant_ident: format_ident!("__{}__MaskType__MatchVariant", ident),
+            mask_type_sim_value_ident: format_ident!("__{}__MaskType__SimValue", ident),
             match_variant_ident: format_ident!("__{}__MatchVariant", ident),
+            sim_value_ident: format_ident!("__{}__SimValue", ident),
             mask_type_builder_ident: format_ident!("__{}__MaskType__Builder", ident),
             builder_ident: format_ident!("__{}__Builder", ident),
             ident,
@@ -426,7 +431,9 @@ impl ToTokens for ParsedBundle {
             field_flips,
             mask_type_ident,
             mask_type_match_variant_ident,
+            mask_type_sim_value_ident,
             match_variant_ident,
+            sim_value_ident,
             builder_ident,
             mask_type_builder_ident,
         } = self;
@@ -437,6 +444,7 @@ impl ToTokens for ParsedBundle {
             custom_bounds: _,
             no_static,
             no_runtime_generics,
+            cmp_eq,
         } = &options.body;
         let target = get_target(target, ident);
         let mut item_attrs = attrs.clone();
@@ -521,7 +529,7 @@ impl ToTokens for ParsedBundle {
             semi_token: None,
         }
         .to_tokens(tokens);
-        let mut mask_type_match_variant_fields = mask_type_fields;
+        let mut mask_type_match_variant_fields = mask_type_fields.clone();
         for Field { ty, .. } in &mut mask_type_match_variant_fields.named {
             *ty = parse_quote_spanned! {span=>
                 ::fayalite::expr::Expr<#ty>
@@ -563,6 +571,58 @@ impl ToTokens for ParsedBundle {
             semi_token: None,
         }
         .to_tokens(tokens);
+        let mut mask_type_sim_value_fields = mask_type_fields;
+        for Field { ty, .. } in &mut mask_type_sim_value_fields.named {
+            *ty = parse_quote_spanned! {span=>
+                ::fayalite::sim::value::SimValue<#ty>
+            };
+        }
+        ItemStruct {
+            attrs: vec![
+                parse_quote_spanned! {span=>
+                    #[::fayalite::__std::prelude::v1::derive(
+                        ::fayalite::__std::fmt::Debug,
+                        ::fayalite::__std::clone::Clone,
+                    )]
+                },
+                parse_quote_spanned! {span=>
+                    #[allow(non_camel_case_types, dead_code)]
+                },
+            ],
+            vis: vis.clone(),
+            struct_token: *struct_token,
+            ident: mask_type_sim_value_ident.clone(),
+            generics: generics.into(),
+            fields: Fields::Named(mask_type_sim_value_fields),
+            semi_token: None,
+        }
+        .to_tokens(tokens);
+        let mut sim_value_fields = FieldsNamed::from(fields.clone());
+        for Field { ty, .. } in &mut sim_value_fields.named {
+            *ty = parse_quote_spanned! {span=>
+                ::fayalite::sim::value::SimValue<#ty>
+            };
+        }
+        ItemStruct {
+            attrs: vec![
+                parse_quote_spanned! {span=>
+                    #[::fayalite::__std::prelude::v1::derive(
+                        ::fayalite::__std::fmt::Debug,
+                        ::fayalite::__std::clone::Clone,
+                    )]
+                },
+                parse_quote_spanned! {span=>
+                    #[allow(non_camel_case_types, dead_code)]
+                },
+            ],
+            vis: vis.clone(),
+            struct_token: *struct_token,
+            ident: sim_value_ident.clone(),
+            generics: generics.into(),
+            fields: Fields::Named(sim_value_fields),
+            semi_token: None,
+        }
+        .to_tokens(tokens);
         let this_token = Ident::new("__this", span);
         let fields_token = Ident::new("__fields", span);
         let self_token = Token![self](span);
@@ -613,6 +673,31 @@ impl ToTokens for ParsedBundle {
                 }
             },
         ));
+        let sim_value_from_bits_fields = Vec::from_iter(fields.named().into_iter().map(|field| {
+            let ident: &Ident = field.ident().as_ref().unwrap();
+            quote_spanned! {span=>
+                #ident: v.field_from_bits(),
+            }
+        }));
+        let sim_value_clone_from_bits_fields =
+            Vec::from_iter(fields.named().into_iter().map(|field| {
+                let ident: &Ident = field.ident().as_ref().unwrap();
+                quote_spanned! {span=>
+                    v.field_clone_from_bits(&mut value.#ident);
+                }
+            }));
+        let sim_value_to_bits_fields = Vec::from_iter(fields.named().into_iter().map(|field| {
+            let ident: &Ident = field.ident().as_ref().unwrap();
+            quote_spanned! {span=>
+                v.field_to_bits(&value.#ident);
+            }
+        }));
+        let to_sim_value_fields = Vec::from_iter(fields.named().into_iter().map(|field| {
+            let ident: &Ident = field.ident().as_ref().unwrap();
+            quote_spanned! {span=>
+                #ident: ::fayalite::sim::value::SimValue::ty(&self.#ident),
+            }
+        }));
         let fields_len = fields.named().into_iter().len();
         quote_spanned! {span=>
             #[automatically_derived]
@@ -621,6 +706,7 @@ impl ToTokens for ParsedBundle {
             {
                 type BaseType = ::fayalite::bundle::Bundle;
                 type MaskType = #mask_type_ident #type_generics;
+                type SimValue = #mask_type_sim_value_ident #type_generics;
                 type MatchVariant = #mask_type_match_variant_ident #type_generics;
                 type MatchActiveScope = ();
                 type MatchVariantAndInactiveScope = ::fayalite::ty::MatchVariantWithoutScope<
@@ -658,6 +744,34 @@ impl ToTokens for ParsedBundle {
                 fn source_location() -> ::fayalite::source_location::SourceLocation {
                     ::fayalite::source_location::SourceLocation::caller()
                 }
+                fn sim_value_from_bits(
+                    &self,
+                    bits: &::fayalite::bitvec::slice::BitSlice,
+                ) -> <Self as ::fayalite::ty::Type>::SimValue {
+                    #![allow(unused_mut, unused_variables)]
+                    let mut v = ::fayalite::bundle::BundleSimValueFromBits::new(*self, bits);
+                    #mask_type_sim_value_ident {
+                        #(#sim_value_from_bits_fields)*
+                    }
+                }
+                fn sim_value_clone_from_bits(
+                    &self,
+                    value: &mut <Self as ::fayalite::ty::Type>::SimValue,
+                    bits: &::fayalite::bitvec::slice::BitSlice,
+                ) {
+                    #![allow(unused_mut, unused_variables)]
+                    let mut v = ::fayalite::bundle::BundleSimValueFromBits::new(*self, bits);
+                    #(#sim_value_clone_from_bits_fields)*
+                }
+                fn sim_value_to_bits(
+                    &self,
+                    value: &<Self as ::fayalite::ty::Type>::SimValue,
+                    bits: &mut ::fayalite::bitvec::slice::BitSlice,
+                ) {
+                    #![allow(unused_mut, unused_variables)]
+                    let mut v = ::fayalite::bundle::BundleSimValueToBits::new(*self, bits);
+                    #(#sim_value_to_bits_fields)*
+                }
             }
             #[automatically_derived]
             impl #impl_generics ::fayalite::bundle::BundleType for #mask_type_ident #type_generics
@@ -689,11 +803,57 @@ impl ToTokens for ParsedBundle {
                 }
             }
             #[automatically_derived]
+            impl #impl_generics ::fayalite::sim::value::ToSimValue for #mask_type_sim_value_ident #type_generics
+            #where_clause
+            {
+                type Type = #mask_type_ident #type_generics;
+
+                fn to_sim_value(
+                    &self,
+                ) -> ::fayalite::sim::value::SimValue<
+                    <Self as ::fayalite::sim::value::ToSimValue>::Type,
+                > {
+                    let ty = #mask_type_ident {
+                        #(#to_sim_value_fields)*
+                    };
+                    ::fayalite::sim::value::SimValue::from_value(ty, ::fayalite::__std::clone::Clone::clone(self))
+                }
+                fn into_sim_value(
+                    self,
+                ) -> ::fayalite::sim::value::SimValue<
+                    <Self as ::fayalite::sim::value::ToSimValue>::Type,
+                > {
+                    let ty = #mask_type_ident {
+                        #(#to_sim_value_fields)*
+                    };
+                    ::fayalite::sim::value::SimValue::from_value(ty, self)
+                }
+            }
+            #[automatically_derived]
+            impl #impl_generics ::fayalite::sim::value::ToSimValueWithType<#mask_type_ident #type_generics>
+            for #mask_type_sim_value_ident #type_generics
+            #where_clause
+            {
+                fn to_sim_value_with_type(
+                    &self,
+                    ty: #mask_type_ident #type_generics,
+                ) -> ::fayalite::sim::value::SimValue<#mask_type_ident #type_generics> {
+                    ::fayalite::sim::value::SimValue::from_value(ty, ::fayalite::__std::clone::Clone::clone(self))
+                }
+                fn into_sim_value_with_type(
+                    self,
+                    ty: #mask_type_ident #type_generics,
+                ) -> ::fayalite::sim::value::SimValue<#mask_type_ident #type_generics> {
+                    ::fayalite::sim::value::SimValue::from_value(ty, self)
+                }
+            }
+            #[automatically_derived]
             impl #impl_generics ::fayalite::ty::Type for #target #type_generics
             #where_clause
             {
                 type BaseType = ::fayalite::bundle::Bundle;
                 type MaskType = #mask_type_ident #type_generics;
+                type SimValue = #sim_value_ident #type_generics;
                 type MatchVariant = #match_variant_ident #type_generics;
                 type MatchActiveScope = ();
                 type MatchVariantAndInactiveScope = ::fayalite::ty::MatchVariantWithoutScope<
@@ -733,6 +893,34 @@ impl ToTokens for ParsedBundle {
                 fn source_location() -> ::fayalite::source_location::SourceLocation {
                     ::fayalite::source_location::SourceLocation::caller()
                 }
+                fn sim_value_from_bits(
+                    &self,
+                    bits: &::fayalite::bitvec::slice::BitSlice,
+                ) -> <Self as ::fayalite::ty::Type>::SimValue {
+                    #![allow(unused_mut, unused_variables)]
+                    let mut v = ::fayalite::bundle::BundleSimValueFromBits::new(*self, bits);
+                    #sim_value_ident {
+                        #(#sim_value_from_bits_fields)*
+                    }
+                }
+                fn sim_value_clone_from_bits(
+                    &self,
+                    value: &mut <Self as ::fayalite::ty::Type>::SimValue,
+                    bits: &::fayalite::bitvec::slice::BitSlice,
+                ) {
+                    #![allow(unused_mut, unused_variables)]
+                    let mut v = ::fayalite::bundle::BundleSimValueFromBits::new(*self, bits);
+                    #(#sim_value_clone_from_bits_fields)*
+                }
+                fn sim_value_to_bits(
+                    &self,
+                    value: &<Self as ::fayalite::ty::Type>::SimValue,
+                    bits: &mut ::fayalite::bitvec::slice::BitSlice,
+                ) {
+                    #![allow(unused_mut, unused_variables)]
+                    let mut v = ::fayalite::bundle::BundleSimValueToBits::new(*self, bits);
+                    #(#sim_value_to_bits_fields)*
+                }
             }
             #[automatically_derived]
             impl #impl_generics ::fayalite::bundle::BundleType for #target #type_generics
@@ -763,8 +951,144 @@ impl ToTokens for ParsedBundle {
                     ::fayalite::intern::Interned::into_inner(::fayalite::intern::Intern::intern_sized(__retval))
                 }
             }
+            #[automatically_derived]
+            impl #impl_generics ::fayalite::sim::value::ToSimValue for #sim_value_ident #type_generics
+            #where_clause
+            {
+                type Type = #target #type_generics;
+
+                fn to_sim_value(
+                    &self,
+                ) -> ::fayalite::sim::value::SimValue<
+                    <Self as ::fayalite::sim::value::ToSimValue>::Type,
+                > {
+                    let ty = #target {
+                        #(#to_sim_value_fields)*
+                    };
+                    ::fayalite::sim::value::SimValue::from_value(ty, ::fayalite::__std::clone::Clone::clone(self))
+                }
+                fn into_sim_value(
+                    self,
+                ) -> ::fayalite::sim::value::SimValue<
+                    <Self as ::fayalite::sim::value::ToSimValue>::Type,
+                > {
+                    let ty = #target {
+                        #(#to_sim_value_fields)*
+                    };
+                    ::fayalite::sim::value::SimValue::from_value(ty, self)
+                }
+            }
+            #[automatically_derived]
+            impl #impl_generics ::fayalite::sim::value::ToSimValueWithType<#target #type_generics>
+            for #sim_value_ident #type_generics
+            #where_clause
+            {
+                fn to_sim_value_with_type(
+                    &self,
+                    ty: #target #type_generics,
+                ) -> ::fayalite::sim::value::SimValue<#target #type_generics> {
+                    ::fayalite::sim::value::SimValue::from_value(ty, ::fayalite::__std::clone::Clone::clone(self))
+                }
+                fn into_sim_value_with_type(
+                    self,
+                    ty: #target #type_generics,
+                ) -> ::fayalite::sim::value::SimValue<#target #type_generics> {
+                    ::fayalite::sim::value::SimValue::from_value(ty, self)
+                }
+            }
         }
         .to_tokens(tokens);
+        if let Some((cmp_eq,)) = cmp_eq {
+            let mut expr_where_clause =
+                Generics::from(generics)
+                    .where_clause
+                    .unwrap_or_else(|| syn::WhereClause {
+                        where_token: Token![where](span),
+                        predicates: Punctuated::new(),
+                    });
+            let mut sim_value_where_clause = expr_where_clause.clone();
+            let mut fields_sim_value_eq = vec![];
+            let mut fields_cmp_eq = vec![];
+            let mut fields_cmp_ne = vec![];
+            for field in fields.named() {
+                let field_ident = field.ident();
+                let field_ty = field.ty();
+                expr_where_clause
+                    .predicates
+                    .push(parse_quote_spanned! {cmp_eq.span=>
+                        #field_ty: ::fayalite::expr::ops::ExprPartialEq<#field_ty>
+                    });
+                sim_value_where_clause
+                    .predicates
+                    .push(parse_quote_spanned! {cmp_eq.span=>
+                        #field_ty: ::fayalite::sim::value::SimValuePartialEq<#field_ty>
+                    });
+                fields_sim_value_eq.push(quote_spanned! {span=>
+                    ::fayalite::sim::value::SimValuePartialEq::sim_value_eq(&__lhs.#field_ident, &__rhs.#field_ident)
+                });
+                fields_cmp_eq.push(quote_spanned! {span=>
+                    ::fayalite::expr::ops::ExprPartialEq::cmp_eq(__lhs.#field_ident, __rhs.#field_ident)
+                });
+                fields_cmp_ne.push(quote_spanned! {span=>
+                    ::fayalite::expr::ops::ExprPartialEq::cmp_ne(__lhs.#field_ident, __rhs.#field_ident)
+                });
+            }
+            let sim_value_eq_body;
+            let cmp_eq_body;
+            let cmp_ne_body;
+            if fields_len == 0 {
+                sim_value_eq_body = quote_spanned! {span=>
+                    true
+                };
+                cmp_eq_body = quote_spanned! {span=>
+                    ::fayalite::expr::ToExpr::to_expr(&true)
+                };
+                cmp_ne_body = quote_spanned! {span=>
+                    ::fayalite::expr::ToExpr::to_expr(&false)
+                };
+            } else {
+                sim_value_eq_body = quote_spanned! {span=>
+                    #(#fields_sim_value_eq)&&*
+                };
+                cmp_eq_body = quote_spanned! {span=>
+                    #(#fields_cmp_eq)&*
+                };
+                cmp_ne_body = quote_spanned! {span=>
+                    #(#fields_cmp_ne)|*
+                };
+            };
+            quote_spanned! {span=>
+                #[automatically_derived]
+                impl #impl_generics ::fayalite::expr::ops::ExprPartialEq<Self> for #target #type_generics
+                #expr_where_clause
+                {
+                    fn cmp_eq(
+                        __lhs: ::fayalite::expr::Expr<Self>,
+                        __rhs: ::fayalite::expr::Expr<Self>,
+                    ) -> ::fayalite::expr::Expr<::fayalite::int::Bool> {
+                        #cmp_eq_body
+                    }
+                    fn cmp_ne(
+                        __lhs: ::fayalite::expr::Expr<Self>,
+                        __rhs: ::fayalite::expr::Expr<Self>,
+                    ) -> ::fayalite::expr::Expr<::fayalite::int::Bool> {
+                        #cmp_ne_body
+                    }
+                }
+                #[automatically_derived]
+                impl #impl_generics ::fayalite::sim::value::SimValuePartialEq<Self> for #target #type_generics
+                #sim_value_where_clause
+                {
+                    fn sim_value_eq(
+                        __lhs: &::fayalite::sim::value::SimValue<Self>,
+                        __rhs: &::fayalite::sim::value::SimValue<Self>,
+                    ) -> bool {
+                        #sim_value_eq_body
+                    }
+                }
+            }
+            .to_tokens(tokens);
+        }
         if let (None, MaybeParsed::Parsed(generics)) = (no_static, &self.generics) {
             let static_generics = generics.clone().for_static_type();
             let (static_impl_generics, static_type_generics, static_where_clause) =
@@ -800,6 +1124,14 @@ impl ToTokens for ParsedBundle {
                 }
             }));
             quote_spanned! {span=>
+                #[automatically_derived]
+                impl #static_impl_generics ::fayalite::__std::default::Default for #mask_type_ident #static_type_generics
+                #static_where_clause
+                {
+                    fn default() -> Self {
+                        <Self as ::fayalite::ty::StaticType>::TYPE
+                    }
+                }
                 #[automatically_derived]
                 impl #static_impl_generics ::fayalite::ty::StaticType for #mask_type_ident #static_type_generics
                 #static_where_clause
@@ -822,6 +1154,15 @@ impl ToTokens for ParsedBundle {
                     };
                 }
                 #[automatically_derived]
+                impl #static_impl_generics ::fayalite::__std::default::Default
+                for #target #static_type_generics
+                #static_where_clause
+                {
+                    fn default() -> Self {
+                        <Self as ::fayalite::ty::StaticType>::TYPE
+                    }
+                }
+                #[automatically_derived]
                 impl #static_impl_generics ::fayalite::ty::StaticType for #target #static_type_generics
                 #static_where_clause
                 {

crates/fayalite-proc-macros-impl/src/hdl_enum.rs

@@ -129,6 +129,9 @@ pub(crate) struct ParsedEnum {
     pub(crate) brace_token: Brace,
     pub(crate) variants: Punctuated<ParsedVariant, Token![,]>,
     pub(crate) match_variant_ident: Ident,
+    pub(crate) sim_value_ident: Ident,
+    pub(crate) sim_builder_ident: Ident,
+    pub(crate) sim_builder_ty_field_ident: Ident,
 }
 
 impl ParsedEnum {
@@ -155,7 +158,11 @@ impl ParsedEnum {
             custom_bounds,
             no_static: _,
             no_runtime_generics: _,
+            cmp_eq,
         } = options.body;
+        if let Some((cmp_eq,)) = cmp_eq {
+            errors.error(cmp_eq, "#[hdl(cmp_eq)] is not yet implemented for enums");
+        }
         attrs.retain(|attr| {
             if attr.path().is_ident("repr") {
                 errors.error(attr, "#[repr] is not supported on #[hdl] enums");
@@ -186,6 +193,9 @@ impl ParsedEnum {
             brace_token,
             variants,
             match_variant_ident: format_ident!("__{}__MatchVariant", ident),
+            sim_value_ident: format_ident!("__{}__SimValue", ident),
+            sim_builder_ident: format_ident!("__{}__SimBuilder", ident),
+            sim_builder_ty_field_ident: format_ident!("__ty", span = ident.span()),
             ident,
         })
     }
@@ -203,6 +213,9 @@ impl ToTokens for ParsedEnum {
             brace_token,
             variants,
             match_variant_ident,
+            sim_value_ident,
+            sim_builder_ident,
+            sim_builder_ty_field_ident,
         } = self;
         let span = ident.span();
         let ItemOptions {
@@ -211,6 +224,7 @@ impl ToTokens for ParsedEnum {
             custom_bounds: _,
             no_static,
             no_runtime_generics,
+            cmp_eq: _, // TODO: implement cmp_eq for enums
         } = &options.body;
         let target = get_target(target, ident);
         let mut struct_attrs = attrs.clone();
@@ -404,6 +418,133 @@ impl ToTokens for ParsedEnum {
             )),
         }
         .to_tokens(tokens);
+        let mut struct_attrs = attrs.clone();
+        struct_attrs.push(parse_quote_spanned! {span=>
+            #[allow(dead_code, non_camel_case_types)]
+        });
+        ItemStruct {
+            attrs: struct_attrs,
+            vis: vis.clone(),
+            struct_token: Token![struct](enum_token.span),
+            ident: sim_builder_ident.clone(),
+            generics: generics.into(),
+            fields: FieldsNamed {
+                brace_token: *brace_token,
+                named: Punctuated::from_iter([Field {
+                    attrs: vec![],
+                    vis: Visibility::Inherited,
+                    mutability: FieldMutability::None,
+                    ident: Some(sim_builder_ty_field_ident.clone()),
+                    colon_token: Some(Token![:](span)),
+                    ty: parse_quote_spanned! {span=>
+                        #target #type_generics
+                    },
+                }]),
+            }
+            .into(),
+            semi_token: None,
+        }
+        .to_tokens(tokens);
+        let mut enum_attrs = attrs.clone();
+        enum_attrs.push(parse_quote_spanned! {span=>
+            #[::fayalite::__std::prelude::v1::derive(
+                ::fayalite::__std::fmt::Debug,
+                ::fayalite::__std::clone::Clone,
+            )]
+        });
+        enum_attrs.push(parse_quote_spanned! {span=>
+            #[allow(dead_code, non_camel_case_types)]
+        });
+        let sim_value_has_unknown_variant = !variants.len().is_power_of_two();
+        let sim_value_unknown_variant_name = sim_value_has_unknown_variant.then(|| {
+            let mut name = String::new();
+            let unknown = "Unknown";
+            loop {
+                let orig_len = name.len();
+                name.push_str(unknown);
+                if variants.iter().all(|v| v.ident != name) {
+                    break Ident::new(&name, span);
+                }
+                name.truncate(orig_len);
+                name.push('_');
+            }
+        });
+        let sim_value_unknown_variant =
+            sim_value_unknown_variant_name
+                .as_ref()
+                .map(|unknown_variant_name| {
+                    Pair::End(parse_quote_spanned! {span=>
+                        #unknown_variant_name(::fayalite::enum_::UnknownVariantSimValue)
+                    })
+                });
+        ItemEnum {
+            attrs: enum_attrs,
+            vis: vis.clone(),
+            enum_token: *enum_token,
+            ident: sim_value_ident.clone(),
+            generics: generics.into(),
+            brace_token: *brace_token,
+            variants: Punctuated::from_iter(
+                variants
+                    .pairs()
+                    .map_pair_value_ref(
+                        |ParsedVariant {
+                             attrs,
+                             options: _,
+                             ident,
+                             field,
+                         }| Variant {
+                            attrs: attrs.clone(),
+                            ident: ident.clone(),
+                            fields: match field {
+                                Some(ParsedVariantField {
+                                    paren_token,
+                                    attrs,
+                                    options: _,
+                                    ty,
+                                    comma_token,
+                                }) => Fields::Unnamed(FieldsUnnamed {
+                                    paren_token: *paren_token,
+                                    unnamed: Punctuated::from_iter([
+                                        Pair::new(
+                                            Field {
+                                                attrs: attrs.clone(),
+                                                vis: Visibility::Inherited,
+                                                mutability: FieldMutability::None,
+                                                ident: None,
+                                                colon_token: None,
+                                                ty: parse_quote_spanned! {span=>
+                                                    ::fayalite::sim::value::SimValue<#ty>
+                                                },
+                                            },
+                                            Some(comma_token.unwrap_or(Token![,](ident.span()))),
+                                        ),
+                                        Pair::new(
+                                            Field {
+                                                attrs: vec![],
+                                                vis: Visibility::Inherited,
+                                                mutability: FieldMutability::None,
+                                                ident: None,
+                                                colon_token: None,
+                                                ty: parse_quote_spanned! {span=>
+                                                    ::fayalite::enum_::EnumPaddingSimValue
+                                                },
+                                            },
+                                            None,
+                                        ),
+                                    ]),
+                                }),
+                                None => Fields::Unnamed(parse_quote_spanned! {span=>
+                                    (::fayalite::enum_::EnumPaddingSimValue)
+                                }),
+                            },
+                            discriminant: None,
+                        },
+                    )
+                    .chain(sim_value_unknown_variant),
+            ),
+        }
+        .to_tokens(tokens);
         let self_token = Token![self](span);
         for (index, ParsedVariant { ident, field, .. }) in variants.iter().enumerate() {
             if let Some(ParsedVariantField { ty, .. }) = field {
@@ -430,6 +571,25 @@ impl ToTokens for ParsedEnum {
                             )
                         }
                     }
+                    #[automatically_derived]
+                    impl #impl_generics #sim_builder_ident #type_generics
+                    #where_clause
+                    {
+                        #[allow(non_snake_case, dead_code)]
+                        #vis fn #ident<__V: ::fayalite::sim::value::ToSimValueWithType<#ty>>(
+                            #self_token,
+                            v: __V,
+                        ) -> ::fayalite::sim::value::SimValue<#target #type_generics> {
+                            let v = ::fayalite::sim::value::ToSimValueWithType::into_sim_value_with_type(
+                                v,
+                                #self_token.#sim_builder_ty_field_ident.#ident,
+                            );
+                            ::fayalite::sim::value::SimValue::from_value(
+                                #self_token.#sim_builder_ty_field_ident,
+                                #sim_value_ident::#ident(v, ::fayalite::enum_::EnumPaddingSimValue::new()),
+                            )
+                        }
+                    }
                 }
             } else {
                 quote_spanned! {span=>
@@ -448,6 +608,18 @@ impl ToTokens for ParsedEnum {
                             )
                         }
                     }
+                    #[automatically_derived]
+                    impl #impl_generics #sim_builder_ident #type_generics
+                    #where_clause
+                    {
+                        #[allow(non_snake_case, dead_code)]
+                        #vis fn #ident(#self_token) -> ::fayalite::sim::value::SimValue<#target #type_generics> {
+                            ::fayalite::sim::value::SimValue::from_value(
+                                #self_token.#sim_builder_ty_field_ident,
+                                #sim_value_ident::#ident(::fayalite::enum_::EnumPaddingSimValue::new()),
+                            )
+                        }
+                    }
                 }
             }
             .to_tokens(tokens);
@@ -529,6 +701,142 @@ impl ToTokens for ParsedEnum {
                 }
             },
         ));
+        let sim_value_from_bits_unknown_match_arm = if let Some(sim_value_unknown_variant_name) =
+            &sim_value_unknown_variant_name
+        {
+            quote_spanned! {span=>
+                _ => #sim_value_ident::#sim_value_unknown_variant_name(v.unknown_variant_from_bits()),
+            }
+        } else {
+            quote_spanned! {span=>
+                _ => ::fayalite::__std::unreachable!(),
+            }
+        };
+        let sim_value_from_bits_match_arms = Vec::from_iter(
+            variants
+                .iter()
+                .enumerate()
+                .map(
+                    |(
+                        index,
+                        ParsedVariant {
+                            attrs: _,
+                            options: _,
+                            ident,
+                            field,
+                        },
+                    )| {
+                        if let Some(_) = field {
+                            quote_spanned! {span=>
+                                #index => {
+                                    let (field, padding) = v.variant_with_field_from_bits();
+                                    #sim_value_ident::#ident(field, padding)
+                                }
+                            }
+                        } else {
+                            quote_spanned! {span=>
+                                #index => #sim_value_ident::#ident(
+                                    v.variant_no_field_from_bits(),
+                                ),
+                            }
+                        }
+                    },
+                )
+                .chain([sim_value_from_bits_unknown_match_arm]),
+        );
+        let sim_value_clone_from_bits_unknown_match_arm =
+            if let Some(sim_value_unknown_variant_name) = &sim_value_unknown_variant_name {
+                quote_spanned! {span=>
+                    _ => if let #sim_value_ident::#sim_value_unknown_variant_name(value) = value {
+                        v.unknown_variant_clone_from_bits(value);
+                    } else {
+                        *value = #sim_value_ident::#sim_value_unknown_variant_name(
+                            v.unknown_variant_from_bits(),
+                        );
+                    },
+                }
+            } else {
+                quote_spanned! {span=>
+                    _ => ::fayalite::__std::unreachable!(),
+                }
+            };
+        let sim_value_clone_from_bits_match_arms = Vec::from_iter(
+            variants
+                .iter()
+                .enumerate()
+                .map(
+                    |(
+                        index,
+                        ParsedVariant {
+                            attrs: _,
+                            options: _,
+                            ident,
+                            field,
+                        },
+                    )| {
+                        if let Some(_) = field {
+                            quote_spanned! {span=>
+                                #index => if let #sim_value_ident::#ident(field, padding) = value {
+                                    v.variant_with_field_clone_from_bits(field, padding);
+                                } else {
+                                    let (field, padding) = v.variant_with_field_from_bits();
+                                    *value = #sim_value_ident::#ident(field, padding);
+                                },
+                            }
+                        } else {
+                            quote_spanned! {span=>
+                                #index => if let #sim_value_ident::#ident(padding) = value {
+                                    v.variant_no_field_clone_from_bits(padding);
+                                } else {
+                                    *value = #sim_value_ident::#ident(
+                                        v.variant_no_field_from_bits(),
+                                    );
+                                },
+                            }
+                        }
+                    },
+                )
+                .chain([sim_value_clone_from_bits_unknown_match_arm]),
+        );
+        let sim_value_to_bits_match_arms = Vec::from_iter(
+            variants
+                .iter()
+                .enumerate()
+                .map(
+                    |(
+                        index,
+                        ParsedVariant {
+                            attrs: _,
+                            options: _,
+                            ident,
+                            field,
+                        },
+                    )| {
+                        if let Some(_) = field {
+                            quote_spanned! {span=>
+                                #sim_value_ident::#ident(field, padding) => {
+                                    v.variant_with_field_to_bits(#index, field, padding);
+                                }
+                            }
+                        } else {
+                            quote_spanned! {span=>
+                                #sim_value_ident::#ident(padding) => {
+                                    v.variant_no_field_to_bits(#index, padding);
+                                }
+                            }
+                        }
+                    },
+                )
+                .chain(sim_value_unknown_variant_name.as_ref().map(
+                    |sim_value_unknown_variant_name| {
+                        quote_spanned! {span=>
+                            #sim_value_ident::#sim_value_unknown_variant_name(value) => {
+                                v.unknown_variant_to_bits(value);
+                            }
+                        }
+                    },
+                )),
+        );
         let variants_len = variants.len();
         quote_spanned! {span=>
             #[automatically_derived]
@@ -537,6 +845,7 @@ impl ToTokens for ParsedEnum {
             {
                 type BaseType = ::fayalite::enum_::Enum;
                 type MaskType = ::fayalite::int::Bool;
+                type SimValue = #sim_value_ident #type_generics;
                 type MatchVariant = #match_variant_ident #type_generics;
                 type MatchActiveScope = ::fayalite::module::Scope;
                 type MatchVariantAndInactiveScope = ::fayalite::enum_::EnumMatchVariantAndInactiveScope<Self>;
@@ -569,11 +878,41 @@ impl ToTokens for ParsedEnum {
                 fn source_location() -> ::fayalite::source_location::SourceLocation {
                     ::fayalite::source_location::SourceLocation::caller()
                 }
+                fn sim_value_from_bits(
+                    &self,
+                    bits: &::fayalite::bitvec::slice::BitSlice,
+                ) -> <Self as ::fayalite::ty::Type>::SimValue {
+                    let v = ::fayalite::enum_::EnumSimValueFromBits::new(*self, bits);
+                    match v.discriminant() {
+                        #(#sim_value_from_bits_match_arms)*
+                    }
+                }
+                fn sim_value_clone_from_bits(
+                    &self,
+                    value: &mut <Self as ::fayalite::ty::Type>::SimValue,
+                    bits: &::fayalite::bitvec::slice::BitSlice,
+                ) {
+                    let v = ::fayalite::enum_::EnumSimValueFromBits::new(*self, bits);
+                    match v.discriminant() {
+                        #(#sim_value_clone_from_bits_match_arms)*
+                    }
+                }
+                fn sim_value_to_bits(
+                    &self,
+                    value: &<Self as ::fayalite::ty::Type>::SimValue,
+                    bits: &mut ::fayalite::bitvec::slice::BitSlice,
+                ) {
+                    let v = ::fayalite::enum_::EnumSimValueToBits::new(*self, bits);
+                    match value {
+                        #(#sim_value_to_bits_match_arms)*
+                    }
+                }
             }
             #[automatically_derived]
             impl #impl_generics ::fayalite::enum_::EnumType for #target #type_generics
             #where_clause
             {
+                type SimBuilder = #sim_builder_ident #type_generics;
                 fn match_activate_scope(
                     v: <Self as ::fayalite::ty::Type>::MatchVariantAndInactiveScope,
                 ) -> (<Self as ::fayalite::ty::Type>::MatchVariant, <Self as ::fayalite::ty::Type>::MatchActiveScope) {
@@ -592,6 +931,33 @@ impl ToTokens for ParsedEnum {
                     ][..])
                 }
             }
+            #[automatically_derived]
+            impl #impl_generics ::fayalite::sim::value::ToSimValueWithType<#target #type_generics>
+            for #sim_value_ident #type_generics
+            #where_clause
+            {
+                fn to_sim_value_with_type(
+                    &self,
+                    ty: #target #type_generics,
+                ) -> ::fayalite::sim::value::SimValue<#target #type_generics> {
+                    ::fayalite::sim::value::SimValue::from_value(ty, ::fayalite::__std::clone::Clone::clone(self))
+                }
+                fn into_sim_value_with_type(
+                    self,
+                    ty: #target #type_generics,
+                ) -> ::fayalite::sim::value::SimValue<#target #type_generics> {
+                    ::fayalite::sim::value::SimValue::from_value(ty, self)
+                }
+            }
+            #[automatically_derived]
+            impl #impl_generics ::fayalite::__std::convert::From<#target #type_generics>
+            for #sim_builder_ident #type_generics
+            #where_clause
+            {
+                fn from(#sim_builder_ty_field_ident: #target #type_generics) -> Self {
+                    Self { #sim_builder_ty_field_ident }
+                }
+            }
         }
         .to_tokens(tokens);
         if let (None, MaybeParsed::Parsed(generics)) = (no_static, &self.generics) {
@@ -629,6 +995,15 @@ impl ToTokens for ParsedEnum {
                     }
                 }));
             quote_spanned! {span=>
+                #[automatically_derived]
+                impl #static_impl_generics ::fayalite::__std::default::Default
+                for #target #static_type_generics
+                #static_where_clause
+                {
+                    fn default() -> Self {
+                        <Self as ::fayalite::ty::StaticType>::TYPE
+                    }
+                }
                 #[automatically_derived]
                 impl #static_impl_generics ::fayalite::ty::StaticType
                 for #target #static_type_generics
@@ -647,6 +1022,34 @@ impl ToTokens for ParsedEnum {
                     const MASK_TYPE_PROPERTIES: ::fayalite::ty::TypeProperties =
                         <::fayalite::int::Bool as ::fayalite::ty::StaticType>::TYPE_PROPERTIES;
                 }
+                #[automatically_derived]
+                impl #static_impl_generics ::fayalite::sim::value::ToSimValue
+                for #sim_value_ident #static_type_generics
+                #static_where_clause
+                {
+                    type Type = #target #static_type_generics;
+
+                    fn to_sim_value(
+                        &self,
+                    ) -> ::fayalite::sim::value::SimValue<
+                        <Self as ::fayalite::sim::value::ToSimValue>::Type,
+                    > {
+                        ::fayalite::sim::value::SimValue::from_value(
+                            ::fayalite::ty::StaticType::TYPE,
+                            ::fayalite::__std::clone::Clone::clone(self),
+                        )
+                    }
+                    fn into_sim_value(
+                        self,
+                    ) -> ::fayalite::sim::value::SimValue<
+                        <Self as ::fayalite::sim::value::ToSimValue>::Type,
+                    > {
+                        ::fayalite::sim::value::SimValue::from_value(
+                            ::fayalite::ty::StaticType::TYPE,
+                            self,
+                        )
+                    }
+                }
             }
             .to_tokens(tokens);
         }

crates/fayalite-proc-macros-impl/src/hdl_type_alias.rs

@@ -49,10 +49,14 @@ impl ParsedTypeAlias {
             custom_bounds,
             no_static,
             no_runtime_generics: _,
+            cmp_eq,
         } = options.body;
         if let Some((no_static,)) = no_static {
             errors.error(no_static, "no_static is not valid on type aliases");
         }
+        if let Some((cmp_eq,)) = cmp_eq {
+            errors.error(cmp_eq, "cmp_eq is not valid on type aliases");
+        }
         let generics = if custom_bounds.is_some() {
             MaybeParsed::Unrecognized(generics)
         } else if let Some(generics) = errors.ok(ParsedGenerics::parse(&mut generics)) {
@@ -95,6 +99,7 @@ impl ToTokens for ParsedTypeAlias {
             custom_bounds: _,
             no_static: _,
             no_runtime_generics,
+            cmp_eq: _,
         } = &options.body;
         let target = get_target(target, ident);
         let mut type_attrs = attrs.clone();

crates/fayalite-proc-macros-impl/src/hdl_type_common.rs

@@ -26,6 +26,7 @@ crate::options! {
         CustomBounds(custom_bounds),
         NoStatic(no_static),
         NoRuntimeGenerics(no_runtime_generics),
+        CmpEq(cmp_eq),
     }
 }
 
@@ -2069,11 +2070,16 @@ macro_rules! impl_bounds {
             $(
                 $Variant:ident,
             )*
+            $(
+                #[unknown]
+                $Unknown:ident,
+            )?
         }
     ) => {
         #[derive(Clone, Debug)]
         $vis enum $enum_type {
             $($Variant(known_items::$Variant),)*
+            $($Unknown(syn::TypeParamBound),)?
         }
 
         $(impl From<known_items::$Variant> for $enum_type {
@@ -2086,28 +2092,54 @@ macro_rules! impl_bounds {
             fn to_tokens(&self, tokens: &mut TokenStream) {
                 match self {
                     $(Self::$Variant(v) => v.to_tokens(tokens),)*
+                    $(Self::$Unknown(v) => v.to_tokens(tokens),)?
                 }
             }
         }
 
         impl $enum_type {
             $vis fn parse_path(path: Path) -> Result<Self, Path> {
+                #![allow(unreachable_code)]
                 $(let path = match known_items::$Variant::parse_path(path) {
                     Ok(v) => return Ok(Self::$Variant(v)),
                     Err(path) => path,
                 };)*
+                $(return Ok(Self::$Unknown(syn::TraitBound {
+                    paren_token: None,
+                    modifier: syn::TraitBoundModifier::None,
+                    lifetimes: None,
+                    path,
+                }.into()));)?
                 Err(path)
             }
+            $vis fn parse_type_param_bound(mut type_param_bound: syn::TypeParamBound) -> Result<Self, syn::TypeParamBound> {
+                #![allow(unreachable_code)]
+                if let syn::TypeParamBound::Trait(mut trait_bound) = type_param_bound {
+                    if let syn::TraitBound {
+                        paren_token: _,
+                        modifier: syn::TraitBoundModifier::None,
+                        lifetimes: None,
+                        path: _,
+                    } = trait_bound {
+                        match Self::parse_path(trait_bound.path) {
+                            Ok(retval) => return Ok(retval),
+                            Err(path) => trait_bound.path = path,
+                        }
+                    }
+                    type_param_bound = trait_bound.into();
+                }
+                $(return Ok(Self::$Unknown(type_param_bound));)?
+                Err(type_param_bound)
+            }
         }
 
         impl Parse for $enum_type {
             fn parse(input: ParseStream) -> syn::Result<Self> {
-                Self::parse_path(Path::parse_mod_style(input)?).map_err(|path| {
-                    syn::Error::new_spanned(
-                        path,
+                Self::parse_type_param_bound(input.parse()?)
+                    .map_err(|type_param_bound| syn::Error::new_spanned(
+                        type_param_bound,
                         format_args!("expected one of: {}", [$(stringify!($Variant)),*].join(", ")),
-                    )
-                })
+                    ))
             }
         }
 
@@ -2115,6 +2147,7 @@ macro_rules! impl_bounds {
         #[allow(non_snake_case)]
         $vis struct $struct_type {
             $($vis $Variant: Option<known_items::$Variant>,)*
+            $($vis $Unknown: Vec<syn::TypeParamBound>,)?
         }
 
         impl ToTokens for $struct_type {
@@ -2126,42 +2159,63 @@ macro_rules! impl_bounds {
                     separator = Some(<Token![+]>::default());
                     v.to_tokens(tokens);
                 })*
+                $(for v in &self.$Unknown {
+                    separator.to_tokens(tokens);
+                    separator = Some(<Token![+]>::default());
+                    v.to_tokens(tokens);
+                })*
             }
         }
 
         const _: () = {
             #[derive(Clone, Debug)]
-            $vis struct Iter($vis $struct_type);
+            #[allow(non_snake_case)]
+            $vis struct Iter {
+                $($Variant: Option<known_items::$Variant>,)*
+                $($Unknown: std::vec::IntoIter<syn::TypeParamBound>,)?
+            }
 
             impl IntoIterator for $struct_type {
                 type Item = $enum_type;
                 type IntoIter = Iter;
 
                 fn into_iter(self) -> Self::IntoIter {
-                    Iter(self)
+                    Iter {
+                        $($Variant: self.$Variant,)*
+                        $($Unknown: self.$Unknown.into_iter(),)?
+                    }
                 }
             }
 
             impl Iterator for Iter {
                 type Item = $enum_type;
 
-
                 fn next(&mut self) -> Option<Self::Item> {
                     $(
-                        if let Some(value) = self.0.$Variant.take() {
+                        if let Some(value) = self.$Variant.take() {
                             return Some($enum_type::$Variant(value));
                         }
                     )*
+                    $(
+                        if let Some(value) = self.$Unknown.next() {
+                            return Some($enum_type::$Unknown(value));
+                        }
+                    )?
                     None
                 }
 
                 #[allow(unused_mut, unused_variables)]
                 fn fold<B, F: FnMut(B, Self::Item) -> B>(mut self, mut init: B, mut f: F) -> B {
                     $(
-                        if let Some(value) = self.0.$Variant.take() {
+                        if let Some(value) = self.$Variant.take() {
                             init = f(init, $enum_type::$Variant(value));
                         }
                     )*
+                    $(
+                        if let Some(value) = self.$Unknown.next() {
+                            init = f(init, $enum_type::$Unknown(value));
+                        }
+                    )?
                     init
                 }
             }
@@ -2173,6 +2227,9 @@ macro_rules! impl_bounds {
                     $($enum_type::$Variant(v) => {
                         self.$Variant = Some(v);
                     })*
+                    $($enum_type::$Unknown(v) => {
+                        self.$Unknown.push(v);
+                    })?
                 });
             }
         }
@@ -2191,6 +2248,7 @@ macro_rules! impl_bounds {
                     $(if let Some(v) = v.$Variant {
                         self.$Variant = Some(v);
                     })*
+                    $(self.$Unknown.extend(v.$Unknown);)*
                 });
             }
         }
@@ -2244,6 +2302,8 @@ impl_bounds! {
         Size,
         StaticType,
         Type,
+        #[unknown]
+        Unknown,
     }
 }
 
@@ -2257,6 +2317,8 @@ impl_bounds! {
         ResetType,
         StaticType,
         Type,
+        #[unknown]
+        Unknown,
     }
 }
 
@@ -2270,6 +2332,7 @@ impl From<ParsedTypeBound> for ParsedBound {
             ParsedTypeBound::ResetType(v) => ParsedBound::ResetType(v),
             ParsedTypeBound::StaticType(v) => ParsedBound::StaticType(v),
             ParsedTypeBound::Type(v) => ParsedBound::Type(v),
+            ParsedTypeBound::Unknown(v) => ParsedBound::Unknown(v),
         }
     }
 }
@@ -2284,6 +2347,7 @@ impl From<ParsedTypeBounds> for ParsedBounds {
             ResetType,
             StaticType,
             Type,
+            Unknown,
         } = value;
         Self {
             BoolOrIntType,
@@ -2295,6 +2359,7 @@ impl From<ParsedTypeBounds> for ParsedBounds {
             Size: None,
             StaticType,
             Type,
+            Unknown,
         }
     }
 }
@@ -2330,6 +2395,7 @@ impl ParsedTypeBound {
                 ParsedTypeBound::Type(known_items::Type(span)),
             ]),
             Self::Type(v) => ParsedTypeBounds::from_iter([ParsedTypeBound::from(v)]),
+            Self::Unknown(v) => ParsedTypeBounds::from_iter([ParsedTypeBound::Unknown(v)]),
         }
     }
 }
@@ -2364,6 +2430,7 @@ impl From<ParsedSizeTypeBounds> for ParsedBounds {
             Size,
             StaticType: None,
             Type: None,
+            Unknown: vec![],
         }
     }
 }
@@ -2391,6 +2458,7 @@ impl ParsedBounds {
     fn categorize(self, errors: &mut Errors, span: Span) -> ParsedBoundsCategory {
         let mut type_bounds = None;
         let mut size_type_bounds = None;
+        let mut unknown_bounds = vec![];
         self.into_iter().for_each(|bound| match bound.categorize() {
             ParsedBoundCategory::Type(bound) => {
                 type_bounds
@@ -2402,15 +2470,37 @@ impl ParsedBounds {
                     .get_or_insert_with(ParsedSizeTypeBounds::default)
                     .extend([bound]);
             }
+            ParsedBoundCategory::Unknown(bound) => unknown_bounds.push(bound),
         });
-        match (type_bounds, size_type_bounds) {
-            (None, None) => ParsedBoundsCategory::Type(ParsedTypeBounds {
+        match (type_bounds, size_type_bounds, unknown_bounds.is_empty()) {
+            (None, None, true) => ParsedBoundsCategory::Type(ParsedTypeBounds {
                 Type: Some(known_items::Type(span)),
                 ..Default::default()
             }),
-            (None, Some(bounds)) => ParsedBoundsCategory::SizeType(bounds),
-            (Some(bounds), None) => ParsedBoundsCategory::Type(bounds),
-            (Some(type_bounds), Some(size_type_bounds)) => {
+            (None, None, false) => {
+                errors.error(
+                    unknown_bounds.remove(0),
+                    "unknown bounds: must use at least one known bound (such as `Type`) with any unknown bounds",
+                );
+                ParsedBoundsCategory::Type(ParsedTypeBounds {
+                    Unknown: unknown_bounds,
+                    ..Default::default()
+                })
+            }
+            (None, Some(bounds), true) => ParsedBoundsCategory::SizeType(bounds),
+            (None, Some(bounds), false) => {
+                // TODO: implement
+                errors.error(
+                    unknown_bounds.remove(0),
+                    "unknown bounds with `Size` bounds are not implemented",
+                );
+                ParsedBoundsCategory::SizeType(bounds)
+            }
+            (Some(bounds), None, _) => ParsedBoundsCategory::Type(ParsedTypeBounds {
+                Unknown: unknown_bounds,
+                ..bounds
+            }),
+            (Some(type_bounds), Some(size_type_bounds), _) => {
                 errors.error(
                     size_type_bounds
                         .Size
@@ -2427,6 +2517,7 @@ impl ParsedBounds {
 pub(crate) enum ParsedBoundCategory {
     Type(ParsedTypeBound),
     SizeType(ParsedSizeTypeBound),
+    Unknown(syn::TypeParamBound),
 }
 
 impl ParsedBound {
@@ -2441,12 +2532,14 @@ impl ParsedBound {
             Self::Size(v) => ParsedBoundCategory::SizeType(ParsedSizeTypeBound::Size(v)),
             Self::StaticType(v) => ParsedBoundCategory::Type(ParsedTypeBound::StaticType(v)),
             Self::Type(v) => ParsedBoundCategory::Type(ParsedTypeBound::Type(v)),
+            Self::Unknown(v) => ParsedBoundCategory::Unknown(v),
         }
     }
     fn implied_bounds(self) -> ParsedBounds {
         match self.categorize() {
             ParsedBoundCategory::Type(v) => v.implied_bounds().into(),
             ParsedBoundCategory::SizeType(v) => v.implied_bounds().into(),
+            ParsedBoundCategory::Unknown(v) => ParsedBounds::from_iter([ParsedBound::Unknown(v)]),
         }
     }
 }
@@ -3325,7 +3418,7 @@ impl ParsedGenerics {
                                 | ParsedTypeBound::EnumType(_)
                                 | ParsedTypeBound::IntType(_)
                                 | ParsedTypeBound::ResetType(_) => {
-                                    errors.error(bound, "bound on mask type not implemented");
+                                    errors.error(bound, "bounds on mask types are not implemented");
                                 }
                                 ParsedTypeBound::StaticType(bound) => {
                                     if bounds.StaticType.is_none() {
@@ -3337,6 +3430,12 @@ impl ParsedGenerics {
                                     }
                                 }
                                 ParsedTypeBound::Type(_) => {}
+                                ParsedTypeBound::Unknown(_) => {
+                                    errors.error(
+                                        bound,
+                                        "unknown bounds on mask types are not implemented",
+                                    );
+                                }
                             }
                         }
                         bounds.add_implied_bounds();

crates/fayalite-proc-macros-impl/src/lib.rs

@@ -72,13 +72,14 @@ mod kw {
     custom_keyword!(cfg);
     custom_keyword!(cfg_attr);
     custom_keyword!(clock_domain);
+    custom_keyword!(cmp_eq);
     custom_keyword!(connect_inexact);
     custom_keyword!(custom_bounds);
     custom_keyword!(flip);
     custom_keyword!(hdl);
     custom_keyword!(hdl_module);
-    custom_keyword!(input);
     custom_keyword!(incomplete_wire);
+    custom_keyword!(input);
     custom_keyword!(instance);
     custom_keyword!(m);
     custom_keyword!(memory);
@@ -92,6 +93,7 @@ mod kw {
     custom_keyword!(output);
     custom_keyword!(reg_builder);
     custom_keyword!(reset);
+    custom_keyword!(sim);
     custom_keyword!(skip);
     custom_keyword!(target);
     custom_keyword!(wire);

crates/fayalite-proc-macros-impl/src/module.rs

@@ -377,7 +377,7 @@ impl ModuleFn {
             module_kind,
             vis,
             sig,
-            block,
+            mut block,
             struct_generics,
             the_struct,
         } = match self.0 {
@@ -439,6 +439,12 @@ impl ModuleFn {
         body_sig
             .inputs
             .insert(0, parse_quote! { m: &::fayalite::module::ModuleBuilder });
+        block.stmts.insert(
+            0,
+            parse_quote! {
+                let _ = m;
+            },
+        );
         let body_fn = ItemFn {
             attrs: vec![],
             vis: Visibility::Inherited,

crates/fayalite-proc-macros-impl/src/module/transform_body.rs

@@ -16,7 +16,7 @@ use std::{borrow::Borrow, convert::Infallible};
 use syn::{
     fold::{fold_expr, fold_expr_lit, fold_expr_unary, fold_local, fold_stmt, Fold},
     parenthesized,
-    parse::{Nothing, Parse, ParseStream},
+    parse::{Parse, ParseStream},
     parse_quote, parse_quote_spanned,
     spanned::Spanned,
     token::Paren,
@@ -27,6 +27,13 @@ use syn::{
 mod expand_aggregate_literals;
 mod expand_match;
 
+options! {
+    #[options = ExprOptions]
+    pub(crate) enum ExprOption {
+        Sim(sim),
+    }
+}
+
 options! {
     pub(crate) enum LetFnKind {
         Input(input),
@@ -952,7 +959,7 @@ with_debug_clone_and_fold! {
     #[allow(dead_code)]
     pub(crate) struct HdlLet<Kind = HdlLetKind> {
         pub(crate) attrs: Vec<Attribute>,
-        pub(crate) hdl_attr: HdlAttr<Nothing, kw::hdl>,
+        pub(crate) hdl_attr: HdlAttr<syn::parse::Nothing, kw::hdl>,
         pub(crate) let_token: Token![let],
         pub(crate) mut_token: Option<Token![mut]>,
         pub(crate) name: Ident,
@@ -1173,7 +1180,7 @@ impl Visitor<'_> {
             Some(_) => {}
         }
     }
-    fn process_hdl_if(&mut self, hdl_attr: HdlAttr<Nothing, kw::hdl>, expr_if: ExprIf) -> Expr {
+    fn process_hdl_if(&mut self, hdl_attr: HdlAttr<ExprOptions, kw::hdl>, expr_if: ExprIf) -> Expr {
         let ExprIf {
             attrs,
             if_token,
@@ -1181,10 +1188,10 @@ impl Visitor<'_> {
             then_branch,
             else_branch,
         } = expr_if;
-        self.require_normal_module_or_fn(if_token);
-        let else_expr = else_branch.unzip().1.map(|else_expr| match *else_expr {
-            Expr::If(expr_if) => self.process_hdl_if(hdl_attr.clone(), expr_if),
-            expr => expr,
+        let (else_token, else_expr) = else_branch.unzip();
+        let else_expr = else_expr.map(|else_expr| match *else_expr {
+            Expr::If(expr_if) => Box::new(self.process_hdl_if(hdl_attr.clone(), expr_if)),
+            _ => else_expr,
         });
         if let Expr::Let(ExprLet {
             attrs: let_attrs,
@@ -1206,7 +1213,19 @@ impl Visitor<'_> {
                 },
             );
         }
-        if let Some(else_expr) = else_expr {
+        let ExprOptions { sim } = hdl_attr.body;
+        if sim.is_some() {
+            ExprIf {
+                attrs,
+                if_token,
+                cond: parse_quote_spanned! {if_token.span=>
+                    *::fayalite::sim::value::SimValue::<::fayalite::int::Bool>::value(&::fayalite::sim::value::ToSimValue::into_sim_value(#cond))
+                },
+                then_branch,
+                else_branch: else_token.zip(else_expr),
+            }
+            .into()
+        } else if let Some(else_expr) = else_expr {
             parse_quote_spanned! {if_token.span=>
                 #(#attrs)*
                 {
@@ -1668,6 +1687,8 @@ impl Fold for Visitor<'_> {
                 Repeat => process_hdl_repeat,
                 Struct => process_hdl_struct,
                 Tuple => process_hdl_tuple,
+                MethodCall => process_hdl_method_call,
+                Call => process_hdl_call,
             }
         }
     }
@@ -1675,7 +1696,7 @@ impl Fold for Visitor<'_> {
     fn fold_local(&mut self, mut let_stmt: Local) -> Local {
         match self
             .errors
-            .ok(HdlAttr::<Nothing, kw::hdl>::parse_and_leave_attr(
+            .ok(HdlAttr::<ExprOptions, kw::hdl>::parse_and_leave_attr(
                 &let_stmt.attrs,
             )) {
             None => return empty_let(),
@@ -1694,7 +1715,8 @@ impl Fold for Visitor<'_> {
             subpat: None,
         }) = pat
         else {
-            let hdl_attr = HdlAttr::<Nothing, kw::hdl>::parse_and_take_attr(&mut let_stmt.attrs)
+            let hdl_attr =
+                HdlAttr::<ExprOptions, kw::hdl>::parse_and_take_attr(&mut let_stmt.attrs)
                     .ok()
                     .flatten()
                     .expect("already checked above");

crates/fayalite-proc-macros-impl/src/module/transform_body/expand_aggregate_literals.rs

@@ -1,45 +1,103 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 // See Notices.txt for copyright information
-use crate::{kw, module::transform_body::Visitor, HdlAttr};
+
+use crate::{
+    kw,
+    module::transform_body::{
+        expand_match::{parse_enum_path, EnumPath},
+        ExprOptions, Visitor,
+    },
+    HdlAttr,
+};
 use quote::{format_ident, quote_spanned};
+use std::mem;
 use syn::{
-    parse::Nothing, parse_quote, parse_quote_spanned, spanned::Spanned, Expr, ExprArray, ExprPath,
-    ExprRepeat, ExprStruct, ExprTuple, FieldValue, TypePath,
+    parse_quote_spanned, punctuated::Punctuated, spanned::Spanned, token::Paren, Expr, ExprArray,
+    ExprCall, ExprGroup, ExprMethodCall, ExprParen, ExprPath, ExprRepeat, ExprStruct, ExprTuple,
+    FieldValue, Token, TypePath,
 };
 
 impl Visitor<'_> {
     pub(crate) fn process_hdl_array(
         &mut self,
-        hdl_attr: HdlAttr<Nothing, kw::hdl>,
+        hdl_attr: HdlAttr<ExprOptions, kw::hdl>,
         mut expr_array: ExprArray,
     ) -> Expr {
-        self.require_normal_module_or_fn(hdl_attr);
+        let ExprOptions { sim } = hdl_attr.body;
+        let span = hdl_attr.kw.span;
+        if sim.is_some() {
+            for elem in &mut expr_array.elems {
+                *elem = parse_quote_spanned! {elem.span()=>
+                    ::fayalite::sim::value::ToSimValue::to_sim_value(&(#elem))
+                };
+            }
+            parse_quote_spanned! {span=>
+                ::fayalite::sim::value::ToSimValue::into_sim_value(#expr_array)
+            }
+        } else {
             for elem in &mut expr_array.elems {
                 *elem = parse_quote_spanned! {elem.span()=>
                     ::fayalite::expr::ToExpr::to_expr(&(#elem))
                 };
             }
-        parse_quote! {::fayalite::expr::ToExpr::to_expr(&#expr_array)}
+            parse_quote_spanned! {span=>
+                ::fayalite::expr::ToExpr::to_expr(&#expr_array)
+            }
+        }
     }
     pub(crate) fn process_hdl_repeat(
         &mut self,
-        hdl_attr: HdlAttr<Nothing, kw::hdl>,
+        hdl_attr: HdlAttr<ExprOptions, kw::hdl>,
         mut expr_repeat: ExprRepeat,
     ) -> Expr {
-        self.require_normal_module_or_fn(hdl_attr);
         let repeated_value = &expr_repeat.expr;
+        let ExprOptions { sim } = hdl_attr.body;
+        let span = hdl_attr.kw.span;
+        if sim.is_some() {
+            *expr_repeat.expr = parse_quote_spanned! {repeated_value.span()=>
+                ::fayalite::sim::value::ToSimValue::to_sim_value(&(#repeated_value))
+            };
+            parse_quote_spanned! {span=>
+                ::fayalite::sim::value::ToSimValue::into_sim_value(#expr_repeat)
+            }
+        } else {
             *expr_repeat.expr = parse_quote_spanned! {repeated_value.span()=>
                 ::fayalite::expr::ToExpr::to_expr(&(#repeated_value))
             };
-        parse_quote! {::fayalite::expr::ToExpr::to_expr(&#expr_repeat)}
+            parse_quote_spanned! {span=>
+                ::fayalite::expr::ToExpr::to_expr(&#expr_repeat)
+            }
+        }
     }
     pub(crate) fn process_hdl_struct(
         &mut self,
-        hdl_attr: HdlAttr<Nothing, kw::hdl>,
-        expr_struct: ExprStruct,
+        hdl_attr: HdlAttr<ExprOptions, kw::hdl>,
+        mut expr_struct: ExprStruct,
     ) -> Expr {
-        self.require_normal_module_or_fn(&hdl_attr);
         let name_span = expr_struct.path.segments.last().unwrap().ident.span();
+        let ExprOptions { sim } = hdl_attr.body;
+        if sim.is_some() {
+            let ty_path = TypePath {
+                qself: expr_struct.qself.take(),
+                path: expr_struct.path,
+            };
+            expr_struct.path = parse_quote_spanned! {name_span=>
+                __SimValue::<#ty_path>
+            };
+            for field in &mut expr_struct.fields {
+                let expr = &field.expr;
+                field.expr = parse_quote_spanned! {field.member.span()=>
+                    ::fayalite::sim::value::ToSimValue::to_sim_value(&(#expr))
+                };
+            }
+            return parse_quote_spanned! {name_span=>
+                {
+                    type __SimValue<T> = <T as ::fayalite::ty::Type>::SimValue;
+                    let value: ::fayalite::sim::value::SimValue<#ty_path> = ::fayalite::sim::value::ToSimValue::into_sim_value(#expr_struct);
+                    value
+                }
+            };
+        }
         let builder_ident = format_ident!("__builder", span = name_span);
         let empty_builder = if expr_struct.qself.is_some()
             || expr_struct
@@ -91,12 +149,126 @@ impl Visitor<'_> {
     }
     pub(crate) fn process_hdl_tuple(
         &mut self,
-        hdl_attr: HdlAttr<Nothing, kw::hdl>,
-        expr_tuple: ExprTuple,
+        hdl_attr: HdlAttr<ExprOptions, kw::hdl>,
+        mut expr_tuple: ExprTuple,
     ) -> Expr {
-        self.require_normal_module_or_fn(hdl_attr);
+        let ExprOptions { sim } = hdl_attr.body;
+        if sim.is_some() {
+            for element in &mut expr_tuple.elems {
+                *element = parse_quote_spanned! {element.span()=>
+                    &(#element)
+                };
+            }
+            parse_quote_spanned! {expr_tuple.span()=>
+                ::fayalite::sim::value::ToSimValue::into_sim_value(#expr_tuple)
+            }
+        } else {
             parse_quote_spanned! {expr_tuple.span()=>
                 ::fayalite::expr::ToExpr::to_expr(&#expr_tuple)
             }
         }
     }
+    pub(crate) fn process_hdl_call(
+        &mut self,
+        hdl_attr: HdlAttr<ExprOptions, kw::hdl>,
+        mut expr_call: ExprCall,
+    ) -> Expr {
+        let span = hdl_attr.kw.span;
+        let mut func = &mut *expr_call.func;
+        let EnumPath {
+            variant_path: _,
+            enum_path,
+            variant_name,
+        } = loop {
+            match func {
+                Expr::Group(ExprGroup { expr, .. }) | Expr::Paren(ExprParen { expr, .. }) => {
+                    func = &mut **expr;
+                }
+                Expr::Path(_) => {
+                    let Expr::Path(ExprPath { attrs, qself, path }) =
+                        mem::replace(func, Expr::PLACEHOLDER)
+                    else {
+                        unreachable!();
+                    };
+                    match parse_enum_path(TypePath { qself, path }) {
+                        Ok(path) => break path,
+                        Err(path) => {
+                            self.errors.error(&path, "unsupported enum variant path");
+                            let TypePath { qself, path } = path;
+                            *func = ExprPath { attrs, qself, path }.into();
+                            return expr_call.into();
+                        }
+                    }
+                }
+                _ => {
+                    self.errors.error(
+                        &expr_call.func,
+                        "#[hdl] function call -- function must be a possibly-parenthesized path",
+                    );
+                    return expr_call.into();
+                }
+            }
+        };
+        self.process_hdl_method_call(
+            hdl_attr,
+            ExprMethodCall {
+                attrs: expr_call.attrs,
+                receiver: parse_quote_spanned! {span=>
+                    <#enum_path as ::fayalite::ty::StaticType>::TYPE
+                },
+                dot_token: Token![.](span),
+                method: variant_name,
+                turbofish: None,
+                paren_token: expr_call.paren_token,
+                args: expr_call.args,
+            },
+        )
+    }
+    pub(crate) fn process_hdl_method_call(
+        &mut self,
+        hdl_attr: HdlAttr<ExprOptions, kw::hdl>,
+        mut expr_method_call: ExprMethodCall,
+    ) -> Expr {
+        let ExprOptions { sim } = hdl_attr.body;
+        let span = hdl_attr.kw.span;
+        // remove any number of groups and up to one paren
+        let mut receiver = &mut *expr_method_call.receiver;
+        let mut has_group = false;
+        let receiver = loop {
+            match receiver {
+                Expr::Group(ExprGroup { expr, .. }) => {
+                    has_group = true;
+                    receiver = expr;
+                }
+                Expr::Paren(ExprParen { expr, .. }) => break &mut **expr,
+                receiver @ Expr::Path(_) => break receiver,
+                _ => {
+                    if !has_group {
+                        self.errors.error(
+                            &expr_method_call.receiver,
+                            "#[hdl] on a method call needs parenthesized receiver",
+                        );
+                    }
+                    break &mut *expr_method_call.receiver;
+                }
+            }
+        };
+        let func = if sim.is_some() {
+            parse_quote_spanned! {span=>
+                ::fayalite::enum_::enum_type_to_sim_builder
+            }
+        } else {
+            parse_quote_spanned! {span=>
+                ::fayalite::enum_::assert_is_enum_type
+            }
+        };
+        *expr_method_call.receiver = ExprCall {
+            attrs: vec![],
+            func,
+            paren_token: Paren(span),
+            args: Punctuated::from_iter([mem::replace(receiver, Expr::PLACEHOLDER)]),
+        }
+        .into();
+        expr_method_call.into()
+    }
+}

crates/fayalite-proc-macros-impl/src/module/transform_body/expand_match.rs

@@ -3,7 +3,9 @@
 use crate::{
     fold::{impl_fold, DoFold},
     kw,
-    module::transform_body::{empty_let, with_debug_clone_and_fold, wrap_ty_with_expr, Visitor},
+    module::transform_body::{
+        empty_let, with_debug_clone_and_fold, wrap_ty_with_expr, ExprOptions, Visitor,
+    },
     Errors, HdlAttr, PairsIterExt,
 };
 use proc_macro2::{Span, TokenStream};
@@ -11,7 +13,6 @@ use quote::{format_ident, quote_spanned, ToTokens, TokenStreamExt};
 use std::collections::BTreeSet;
 use syn::{
     fold::{fold_arm, fold_expr_match, fold_local, fold_pat, Fold},
-    parse::Nothing,
     parse_quote_spanned,
     punctuated::Punctuated,
     spanned::Spanned,
@@ -82,7 +83,14 @@ visit_trait! {
         }
     }
     fn visit_match_pat_enum_variant(state: _, v: &MatchPatEnumVariant) {
-        let MatchPatEnumVariant {match_span:_, variant_path: _, enum_path: _, variant_name: _, field } = v;
+        let MatchPatEnumVariant {
+            match_span:_,
+            sim:_,
+            variant_path: _,
+            enum_path: _,
+            variant_name: _,
+            field,
+        } = v;
         if let Some((_, v)) = field {
             state.visit_match_pat_simple(v);
         }
@@ -292,6 +300,7 @@ impl ToTokens for MatchPatTuple {
 with_debug_clone_and_fold! {
     struct MatchPatEnumVariant<> {
         match_span: Span,
+        sim: Option<(kw::sim,)>,
         variant_path: Path,
         enum_path: Path,
         variant_name: Ident,
@@ -303,6 +312,7 @@ impl ToTokens for MatchPatEnumVariant {
     fn to_tokens(&self, tokens: &mut TokenStream) {
         let Self {
             match_span,
+            sim,
             variant_path: _,
             enum_path,
             variant_name,
@@ -312,7 +322,28 @@ impl ToTokens for MatchPatEnumVariant {
             __MatchTy::<#enum_path>::#variant_name
         }
         .to_tokens(tokens);
+        if sim.is_some() {
             if let Some((paren_token, field)) = field {
+                paren_token.surround(tokens, |tokens| {
+                    field.to_tokens(tokens);
+                    match field {
+                        MatchPatSimple::Paren(_)
+                        | MatchPatSimple::Or(_)
+                        | MatchPatSimple::Binding(_)
+                        | MatchPatSimple::Wild(_) => quote_spanned! {*match_span=>
+                            , _
+                        }
+                        .to_tokens(tokens),
+                        MatchPatSimple::Rest(_) => {}
+                    }
+                });
+            } else {
+                quote_spanned! {*match_span=>
+                    (_)
+                }
+                .to_tokens(tokens);
+            }
+        } else if let Some((paren_token, field)) = field {
             paren_token.surround(tokens, |tokens| field.to_tokens(tokens));
         }
     }
@@ -349,13 +380,13 @@ impl ToTokens for MatchPatSimple {
     }
 }
 
-struct EnumPath {
-    variant_path: Path,
-    enum_path: Path,
-    variant_name: Ident,
+pub(crate) struct EnumPath {
+    pub(crate) variant_path: Path,
+    pub(crate) enum_path: Path,
+    pub(crate) variant_name: Ident,
 }
 
-fn parse_enum_path(variant_path: TypePath) -> Result<EnumPath, TypePath> {
+pub(crate) fn parse_enum_path(variant_path: TypePath) -> Result<EnumPath, TypePath> {
     let TypePath {
         qself: None,
         path: variant_path,
@@ -447,6 +478,7 @@ trait ParseMatchPat: Sized {
                         state,
                         MatchPatEnumVariant {
                             match_span: state.match_span,
+                            sim: state.sim,
                             variant_path,
                             enum_path,
                             variant_name,
@@ -493,6 +525,7 @@ trait ParseMatchPat: Sized {
                     state,
                     MatchPatEnumVariant {
                         match_span: state.match_span,
+                        sim: state.sim,
                         variant_path,
                         enum_path,
                         variant_name,
@@ -577,6 +610,7 @@ trait ParseMatchPat: Sized {
                     state,
                     MatchPatEnumVariant {
                         match_span: state.match_span,
+                        sim: state.sim,
                         variant_path,
                         enum_path,
                         variant_name,
@@ -939,6 +973,7 @@ impl Fold for RewriteAsCheckMatch {
 }
 
 struct HdlMatchParseState<'a> {
+    sim: Option<(kw::sim,)>,
     match_span: Span,
     errors: &'a mut Errors,
 }
@@ -981,10 +1016,11 @@ impl<'a> VisitMatchPat<'a> for HdlLetPatVisitState<'a> {
 impl Visitor<'_> {
     pub(crate) fn process_hdl_let_pat(
         &mut self,
-        _hdl_attr: HdlAttr<Nothing, kw::hdl>,
+        hdl_attr: HdlAttr<ExprOptions, kw::hdl>,
         mut let_stmt: Local,
     ) -> Local {
         let span = let_stmt.let_token.span();
+        let ExprOptions { sim } = hdl_attr.body;
         if let Pat::Type(pat) = &mut let_stmt.pat {
             *pat.ty = wrap_ty_with_expr((*pat.ty).clone());
         }
@@ -996,7 +1032,6 @@ impl Visitor<'_> {
             init,
             semi_token,
         } = let_stmt;
-        self.require_normal_module_or_fn(let_token);
         let Some(syn::LocalInit {
             eq_token,
             expr,
@@ -1015,6 +1050,7 @@ impl Visitor<'_> {
         }
         let Ok(pat) = MatchPat::parse(
             &mut HdlMatchParseState {
+                sim,
                 match_span: span,
                 errors: &mut self.errors,
             },
@@ -1031,20 +1067,37 @@ impl Visitor<'_> {
             errors: _,
             bindings,
         } = state;
-        let retval = parse_quote_spanned! {span=>
+        let retval = if sim.is_some() {
+            parse_quote_spanned! {span=>
+                let (#(#bindings,)*) = {
+                    type __MatchTy<T> = <T as ::fayalite::ty::Type>::SimValue;
+                    let __match_value = ::fayalite::sim::value::ToSimValue::to_sim_value(&(#expr));
+                    #let_token #pat #eq_token ::fayalite::sim::value::SimValue::into_value(__match_value) #semi_token
+                    (#(#bindings,)*)
+                };
+            }
+        } else {
+            parse_quote_spanned! {span=>
                 let (#(#bindings,)* __scope,) = {
                     type __MatchTy<T> = <T as ::fayalite::ty::Type>::MatchVariant;
                     let __match_expr = ::fayalite::expr::ToExpr::to_expr(&(#expr));
-                ::fayalite::expr::check_match_expr(__match_expr, |__match_value, __infallible| {
+                    ::fayalite::expr::check_match_expr(
+                        __match_expr,
+                        |__match_value, __infallible| {
                             #[allow(unused_variables)]
                             #check_let_stmt
                             match __infallible {}
-                });
+                        },
+                    );
                     let mut __match_iter = ::fayalite::module::match_(__match_expr);
-                let ::fayalite::__std::option::Option::Some(__match_variant) = ::fayalite::__std::iter::Iterator::next(&mut __match_iter) else {
+                    let ::fayalite::__std::option::Option::Some(__match_variant) =
+                        ::fayalite::__std::iter::Iterator::next(&mut __match_iter)
+                    else {
                         ::fayalite::__std::unreachable!("#[hdl] let with uninhabited type");
                     };
-                let ::fayalite::__std::option::Option::None = ::fayalite::__std::iter::Iterator::next(&mut __match_iter) else {
+                    let ::fayalite::__std::option::Option::None =
+                        ::fayalite::__std::iter::Iterator::next(&mut __match_iter)
+                    else {
                         ::fayalite::__std::unreachable!("#[hdl] let with refutable pattern");
                     };
                     let (__match_variant, __scope) =
@@ -1054,6 +1107,7 @@ impl Visitor<'_> {
                     #let_token #pat #eq_token __match_variant #semi_token
                     (#(#bindings,)* __scope,)
                 };
+            }
         };
         match retval {
             syn::Stmt::Local(retval) => retval,
@@ -1062,7 +1116,7 @@ impl Visitor<'_> {
     }
     pub(crate) fn process_hdl_match(
         &mut self,
-        _hdl_attr: HdlAttr<Nothing, kw::hdl>,
+        hdl_attr: HdlAttr<ExprOptions, kw::hdl>,
         expr_match: ExprMatch,
     ) -> Expr {
         let span = expr_match.match_token.span();
@@ -1074,8 +1128,9 @@ impl Visitor<'_> {
             brace_token: _,
             arms,
         } = expr_match;
-        self.require_normal_module_or_fn(match_token);
+        let ExprOptions { sim } = hdl_attr.body;
         let mut state = HdlMatchParseState {
+            sim,
             match_span: span,
             errors: &mut self.errors,
         };
@@ -1083,7 +1138,18 @@ impl Visitor<'_> {
             arms.into_iter()
                 .filter_map(|arm| MatchArm::parse(&mut state, arm).ok()),
         );
-        let expr = quote_spanned! {span=>
+        let expr = if sim.is_some() {
+            quote_spanned! {span=>
+                {
+                    type __MatchTy<T> = <T as ::fayalite::ty::Type>::SimValue;
+                    let __match_expr = ::fayalite::sim::value::ToSimValue::to_sim_value(&(#expr));
+                    #match_token ::fayalite::sim::value::SimValue::into_value(__match_expr) {
+                        #(#arms)*
+                    }
+                }
+            }
+        } else {
+            quote_spanned! {span=>
                 {
                     type __MatchTy<T> = <T as ::fayalite::ty::Type>::MatchVariant;
                     let __match_expr = ::fayalite::expr::ToExpr::to_expr(&(#expr));
@@ -1101,6 +1167,7 @@ impl Visitor<'_> {
                         }
                     }
                 }
+            }
         };
         syn::parse2(expr).unwrap()
     }

crates/fayalite/Cargo.toml

@@ -40,6 +40,7 @@ fayalite-visit-gen.workspace = true
 
 [features]
 unstable-doc = []
+unstable-test-hasher = []
 
 [package.metadata.docs.rs]
 features = ["unstable-doc"]

crates/fayalite/src/annotations.rs

@@ -12,7 +12,7 @@ use std::{
     ops::Deref,
 };
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 struct CustomFirrtlAnnotationFieldsImpl {
     value: serde_json::Map<String, serde_json::Value>,
     serialized: Interned<str>,

crates/fayalite/src/array.rs

@@ -2,17 +2,24 @@
 // See Notices.txt for copyright information
 
 use crate::{
-    expr::{ops::ArrayIndex, Expr, ToExpr},
-    int::{DynSize, KnownSize, Size, SizeType, DYN_SIZE},
+    expr::{
+        ops::{ArrayLiteral, ExprFromIterator, ExprIntoIterator, ExprPartialEq},
+        CastToBits, Expr, HdlPartialEq, ReduceBits, ToExpr,
+    },
+    int::{Bool, DynSize, KnownSize, Size, SizeType, DYN_SIZE},
     intern::{Intern, Interned, LazyInterned},
     module::transform::visit::{Fold, Folder, Visit, Visitor},
+    sim::value::{SimValue, SimValuePartialEq},
     source_location::SourceLocation,
     ty::{
-        CanonicalType, MatchVariantWithoutScope, StaticType, Type, TypeProperties, TypeWithDeref,
+        serde_impls::SerdeCanonicalType, CanonicalType, MatchVariantWithoutScope, StaticType, Type,
+        TypeProperties, TypeWithDeref,
     },
     util::ConstUsize,
 };
-use std::ops::Index;
+use bitvec::slice::BitSlice;
+use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
+use std::{iter::FusedIterator, ops::Index};
 
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
 pub struct ArrayType<T: Type = CanonicalType, Len: Size = DynSize> {
@@ -91,6 +98,12 @@ impl<T: Type, Len: KnownSize + Size<SizeType = Len>> ArrayType<T, Len> {
     }
 }
 
+impl<T: StaticType, Len: KnownSize> Default for ArrayType<T, Len> {
+    fn default() -> Self {
+        Self::TYPE
+    }
+}
+
 impl<T: StaticType, Len: KnownSize> StaticType for ArrayType<T, Len> {
     const TYPE: Self = Self {
         element: LazyInterned::new_lazy(&|| T::TYPE.intern_sized()),
@@ -139,6 +152,7 @@ impl<T: Type + Visit<State>, Len: Size, State: Visitor + ?Sized> Visit<State>
 impl<T: Type, Len: Size> Type for ArrayType<T, Len> {
     type BaseType = Array;
     type MaskType = ArrayType<T::MaskType, Len>;
+    type SimValue = Len::ArraySimValue<T>;
     type MatchVariant = Len::ArrayMatch<T>;
     type MatchActiveScope = ();
     type MatchVariantAndInactiveScope = MatchVariantWithoutScope<Len::ArrayMatch<T>>;
@@ -148,10 +162,8 @@ impl<T: Type, Len: Size> Type for ArrayType<T, Len> {
         this: Expr<Self>,
         source_location: SourceLocation,
     ) -> Self::MatchVariantsIter {
-        let base = Expr::as_dyn_array(this);
-        let base_ty = Expr::ty(base);
         let _ = source_location;
-        let retval = Vec::from_iter((0..base_ty.len()).map(|i| ArrayIndex::new(base, i).to_expr()));
+        let retval = Vec::from_iter(this);
         std::iter::once(MatchVariantWithoutScope(
             Len::ArrayMatch::<T>::try_from(retval)
                 .ok()
@@ -177,16 +189,97 @@ impl<T: Type, Len: Size> Type for ArrayType<T, Len> {
             Len::from_usize(array.len()),
         )
     }
+
     fn source_location() -> SourceLocation {
         SourceLocation::builtin()
     }
+
+    fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+        assert_eq!(bits.len(), self.type_properties.bit_width);
+        let element = self.element();
+        let element_bit_width = element.canonical().bit_width();
+        TryFrom::try_from(Vec::from_iter((0..self.len()).map(|i| {
+            SimValue::from_bitslice(element, &bits[i * element_bit_width..][..element_bit_width])
+        })))
+        .ok()
+        .expect("used correct length")
+    }
+
+    fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+        assert_eq!(bits.len(), self.type_properties.bit_width);
+        let element_ty = self.element();
+        let element_bit_width = element_ty.canonical().bit_width();
+        let value: &mut [SimValue<T>] = value.as_mut();
+        assert_eq!(self.len(), value.len());
+        for (i, element_value) in value.iter_mut().enumerate() {
+            assert_eq!(SimValue::ty(element_value), element_ty);
+            SimValue::bits_mut(element_value)
+                .bits_mut()
+                .copy_from_bitslice(&bits[i * element_bit_width..][..element_bit_width]);
+        }
+    }
+
+    fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+        assert_eq!(bits.len(), self.type_properties.bit_width);
+        let element_ty = self.element();
+        let element_bit_width = element_ty.canonical().bit_width();
+        let value: &[SimValue<T>] = value.as_ref();
+        assert_eq!(self.len(), value.len());
+        for (i, element_value) in value.iter().enumerate() {
+            assert_eq!(SimValue::ty(element_value), element_ty);
+            bits[i * element_bit_width..][..element_bit_width]
+                .copy_from_bitslice(SimValue::bits(element_value).bits());
+        }
+    }
+}
+
+impl<T: Type + Serialize, Len: Size> Serialize for ArrayType<T, Len> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        SerdeCanonicalType::<T>::Array {
+            element: self.element(),
+            len: self.len(),
+        }
+        .serialize(serializer)
+    }
+}
+
+impl<'de, T: Type + Deserialize<'de>, Len: Size> Deserialize<'de> for ArrayType<T, Len> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let name = |len| -> String {
+            if let Some(len) = len {
+                format!("an Array<_, {len}>")
+            } else {
+                "an Array<_>".to_string()
+            }
+        };
+        match SerdeCanonicalType::<T>::deserialize(deserializer)? {
+            SerdeCanonicalType::Array { element, len } => {
+                if let Some(len) = Len::try_from_usize(len) {
+                    Ok(Self::new(element, len))
+                } else {
+                    Err(Error::invalid_value(
+                        serde::de::Unexpected::Other(&name(Some(len))),
+                        &&*name(Len::KNOWN_VALUE),
+                    ))
+                }
+            }
+            ty => Err(Error::invalid_value(
+                serde::de::Unexpected::Other(ty.as_serde_unexpected_str()),
+                &&*name(Len::KNOWN_VALUE),
+            )),
+        }
+    }
 }
 
 impl<T: Type, Len: Size> TypeWithDeref for ArrayType<T, Len> {
     fn expr_deref(this: &Expr<Self>) -> &Self::MatchVariant {
-        let base = Expr::as_dyn_array(*this);
-        let base_ty = Expr::ty(base);
-        let retval = Vec::from_iter((0..base_ty.len()).map(|i| ArrayIndex::new(base, i).to_expr()));
+        let retval = Vec::from_iter(*this);
         Interned::into_inner(Intern::intern_sized(
             Len::ArrayMatch::<T>::try_from(retval)
                 .ok()
@@ -218,3 +311,143 @@ impl<T: Type, L: SizeType> Index<L> for ArrayWithoutLen<T> {
         Interned::into_inner(Intern::intern_sized(ArrayType::new(self.element, len)))
     }
 }
+
+impl<Lhs: Type, Rhs: Type, Len: Size> ExprPartialEq<ArrayType<Rhs, Len>> for ArrayType<Lhs, Len>
+where
+    Lhs: ExprPartialEq<Rhs>,
+{
+    fn cmp_eq(lhs: Expr<Self>, rhs: Expr<ArrayType<Rhs, Len>>) -> Expr<Bool> {
+        let lhs_ty = Expr::ty(lhs);
+        let rhs_ty = Expr::ty(rhs);
+        assert_eq!(lhs_ty.len(), rhs_ty.len());
+        lhs.into_iter()
+            .zip(rhs)
+            .map(|(l, r)| l.cmp_eq(r))
+            .collect::<Expr<Array<Bool>>>()
+            .cast_to_bits()
+            .all_one_bits()
+    }
+
+    fn cmp_ne(lhs: Expr<Self>, rhs: Expr<ArrayType<Rhs, Len>>) -> Expr<Bool> {
+        let lhs_ty = Expr::ty(lhs);
+        let rhs_ty = Expr::ty(rhs);
+        assert_eq!(lhs_ty.len(), rhs_ty.len());
+        lhs.into_iter()
+            .zip(rhs)
+            .map(|(l, r)| l.cmp_ne(r))
+            .collect::<Expr<Array<Bool>>>()
+            .cast_to_bits()
+            .any_one_bits()
+    }
+}
+
+impl<Lhs: Type, Rhs: Type, Len: Size> SimValuePartialEq<ArrayType<Rhs, Len>> for ArrayType<Lhs, Len>
+where
+    Lhs: SimValuePartialEq<Rhs>,
+{
+    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<ArrayType<Rhs, Len>>) -> bool {
+        AsRef::<[_]>::as_ref(&**this)
+            .iter()
+            .zip(AsRef::<[_]>::as_ref(&**other))
+            .all(|(l, r)| SimValuePartialEq::sim_value_eq(l, r))
+    }
+}
+
+impl<T: Type, Len: Size> ExprIntoIterator for ArrayType<T, Len> {
+    type Item = T;
+    type ExprIntoIter = ExprArrayIter<T, Len>;
+
+    fn expr_into_iter(e: Expr<Self>) -> Self::ExprIntoIter {
+        ExprArrayIter {
+            base: e,
+            indexes: 0..Expr::ty(e).len(),
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct ExprArrayIter<T: Type, Len: Size> {
+    base: Expr<ArrayType<T, Len>>,
+    indexes: std::ops::Range<usize>,
+}
+
+impl<T: Type, Len: Size> ExprArrayIter<T, Len> {
+    pub fn base(&self) -> Expr<ArrayType<T, Len>> {
+        self.base
+    }
+    pub fn indexes(&self) -> std::ops::Range<usize> {
+        self.indexes.clone()
+    }
+}
+
+impl<T: Type, Len: Size> Iterator for ExprArrayIter<T, Len> {
+    type Item = Expr<T>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.indexes.next().map(|i| self.base[i])
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.indexes.size_hint()
+    }
+
+    fn count(self) -> usize {
+        self.indexes.count()
+    }
+
+    fn last(mut self) -> Option<Self::Item> {
+        self.next_back()
+    }
+
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        self.indexes.nth(n).map(|i| self.base[i])
+    }
+
+    fn fold<B, F>(self, init: B, mut f: F) -> B
+    where
+        F: FnMut(B, Self::Item) -> B,
+    {
+        self.indexes.fold(init, |b, i| f(b, self.base[i]))
+    }
+}
+
+impl<T: Type, Len: Size> DoubleEndedIterator for ExprArrayIter<T, Len> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.indexes.next_back().map(|i| self.base[i])
+    }
+
+    fn nth_back(&mut self, n: usize) -> Option<Self::Item> {
+        self.indexes.nth_back(n).map(|i| self.base[i])
+    }
+
+    fn rfold<B, F>(self, init: B, mut f: F) -> B
+    where
+        F: FnMut(B, Self::Item) -> B,
+    {
+        self.indexes.rfold(init, |b, i| f(b, self.base[i]))
+    }
+}
+
+impl<T: Type, Len: Size> ExactSizeIterator for ExprArrayIter<T, Len> {
+    fn len(&self) -> usize {
+        self.indexes.len()
+    }
+}
+
+impl<T: Type, Len: Size> FusedIterator for ExprArrayIter<T, Len> {}
+
+impl<A: StaticType> ExprFromIterator<Expr<A>> for Array<A> {
+    fn expr_from_iter<T: IntoIterator<Item = Expr<A>>>(iter: T) -> Expr<Self> {
+        ArrayLiteral::new(
+            A::TYPE,
+            iter.into_iter().map(|v| Expr::canonical(v)).collect(),
+        )
+        .to_expr()
+    }
+}
+
+impl<'a, A: StaticType> ExprFromIterator<&'a Expr<A>> for Array<A> {
+    fn expr_from_iter<T: IntoIterator<Item = &'a Expr<A>>>(iter: T) -> Expr<Self> {
+        iter.into_iter().copied().collect()
+    }
+}

crates/fayalite/src/bundle.rs

@@ -2,20 +2,25 @@
 // See Notices.txt for copyright information
 
 use crate::{
-    expr::{ops::BundleLiteral, Expr, ToExpr},
+    expr::{
+        ops::{ArrayLiteral, BundleLiteral, ExprPartialEq},
+        CastToBits, Expr, ReduceBits, ToExpr,
+    },
+    int::{Bool, DynSize},
     intern::{Intern, Interned},
-    sim::{SimValue, ToSimValue},
+    sim::value::{SimValue, SimValuePartialEq, ToSimValue, ToSimValueWithType},
     source_location::SourceLocation,
     ty::{
-        impl_match_variant_as_self, CanonicalType, MatchVariantWithoutScope, StaticType, Type,
-        TypeProperties, TypeWithDeref,
+        impl_match_variant_as_self, CanonicalType, MatchVariantWithoutScope, OpaqueSimValue,
+        StaticType, Type, TypeProperties, TypeWithDeref,
     },
+    util::HashMap,
 };
-use bitvec::vec::BitVec;
-use hashbrown::HashMap;
+use bitvec::{slice::BitSlice, vec::BitVec};
+use serde::{Deserialize, Serialize};
 use std::{fmt, marker::PhantomData};
 
-#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, Serialize, Deserialize)]
 pub struct BundleField {
     pub name: Interned<str>,
     pub flipped: bool,
@@ -155,7 +160,7 @@ impl Default for BundleTypePropertiesBuilder {
 impl Bundle {
     #[track_caller]
     pub fn new(fields: Interned<[BundleField]>) -> Self {
-        let mut name_indexes = HashMap::with_capacity(fields.len());
+        let mut name_indexes = HashMap::with_capacity_and_hasher(fields.len(), Default::default());
         let mut field_offsets = Vec::with_capacity(fields.len());
         let mut type_props_builder = BundleTypePropertiesBuilder::new();
         for (index, &BundleField { name, flipped, ty }) in fields.iter().enumerate() {
@@ -212,6 +217,7 @@ impl Bundle {
 impl Type for Bundle {
     type BaseType = Bundle;
     type MaskType = Bundle;
+    type SimValue = OpaqueSimValue;
     impl_match_variant_as_self!();
     fn mask_type(&self) -> Self::MaskType {
         Self::new(Interned::from_iter(self.0.fields.into_iter().map(
@@ -235,6 +241,20 @@ impl Type for Bundle {
     fn source_location() -> SourceLocation {
         SourceLocation::builtin()
     }
+    fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+        assert_eq!(bits.len(), self.type_properties().bit_width);
+        OpaqueSimValue::from_bitslice(bits)
+    }
+    fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+        assert_eq!(bits.len(), self.type_properties().bit_width);
+        assert_eq!(value.bit_width(), self.type_properties().bit_width);
+        value.bits_mut().bits_mut().copy_from_bitslice(bits);
+    }
+    fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+        assert_eq!(bits.len(), self.type_properties().bit_width);
+        assert_eq!(value.bit_width(), self.type_properties().bit_width);
+        bits.copy_from_bitslice(value.bits().bits());
+    }
 }
 
 pub trait BundleType: Type<BaseType = Bundle> {
@@ -243,6 +263,93 @@ pub trait BundleType: Type<BaseType = Bundle> {
     fn fields(&self) -> Interned<[BundleField]>;
 }
 
+pub struct BundleSimValueFromBits<'a> {
+    fields: std::slice::Iter<'static, BundleField>,
+    bits: &'a BitSlice,
+}
+
+impl<'a> BundleSimValueFromBits<'a> {
+    #[track_caller]
+    pub fn new<T: BundleType>(bundle_ty: T, bits: &'a BitSlice) -> Self {
+        let fields = bundle_ty.fields();
+        assert_eq!(
+            bits.len(),
+            fields
+                .iter()
+                .map(|BundleField { ty, .. }| ty.bit_width())
+                .sum::<usize>()
+        );
+        Self {
+            fields: Interned::into_inner(fields).iter(),
+            bits,
+        }
+    }
+    #[track_caller]
+    fn field_ty_and_bits<T: Type>(&mut self) -> (T, &'a BitSlice) {
+        let Some(&BundleField {
+            name: _,
+            flipped: _,
+            ty,
+        }) = self.fields.next()
+        else {
+            panic!("tried to read too many fields from BundleSimValueFromBits");
+        };
+        let (field_bits, rest) = self.bits.split_at(ty.bit_width());
+        self.bits = rest;
+        (T::from_canonical(ty), field_bits)
+    }
+    #[track_caller]
+    pub fn field_from_bits<T: Type>(&mut self) -> SimValue<T> {
+        let (field_ty, field_bits) = self.field_ty_and_bits::<T>();
+        SimValue::from_bitslice(field_ty, field_bits)
+    }
+    #[track_caller]
+    pub fn field_clone_from_bits<T: Type>(&mut self, field_value: &mut SimValue<T>) {
+        let (field_ty, field_bits) = self.field_ty_and_bits::<T>();
+        assert_eq!(field_ty, SimValue::ty(field_value));
+        SimValue::bits_mut(field_value)
+            .bits_mut()
+            .copy_from_bitslice(field_bits);
+    }
+}
+
+pub struct BundleSimValueToBits<'a> {
+    fields: std::slice::Iter<'static, BundleField>,
+    bits: &'a mut BitSlice,
+}
+
+impl<'a> BundleSimValueToBits<'a> {
+    #[track_caller]
+    pub fn new<T: BundleType>(bundle_ty: T, bits: &'a mut BitSlice) -> Self {
+        let fields = bundle_ty.fields();
+        assert_eq!(
+            bits.len(),
+            fields
+                .iter()
+                .map(|BundleField { ty, .. }| ty.bit_width())
+                .sum::<usize>()
+        );
+        Self {
+            fields: Interned::into_inner(fields).iter(),
+            bits,
+        }
+    }
+    #[track_caller]
+    pub fn field_to_bits<T: Type>(&mut self, field_value: &SimValue<T>) {
+        let Some(&BundleField {
+            name: _,
+            flipped: _,
+            ty,
+        }) = self.fields.next()
+        else {
+            panic!("tried to read too many fields from BundleSimValueFromBits");
+        };
+        assert_eq!(T::from_canonical(ty), SimValue::ty(field_value));
+        self.bits[..ty.bit_width()].copy_from_bitslice(SimValue::bits(field_value).bits());
+        self.bits = &mut std::mem::take(&mut self.bits)[ty.bit_width()..];
+    }
+}
+
 #[derive(Default)]
 pub struct NoBuilder;
 
@@ -325,7 +432,19 @@ macro_rules! impl_tuple_builder_fields {
 }
 
 macro_rules! impl_tuples {
-    ([$({#[num = $num:literal, field = $field:ident, ty = $ty_var:ident: $Ty:ident] $var:ident: $T:ident})*] []) => {
+    (
+        [$({
+            #[
+                num = $num:tt,
+                field = $field:ident,
+                ty = $ty_var:ident: $Ty:ident,
+                lhs = $lhs_var:ident: $Lhs:ident,
+                rhs = $rhs_var:ident: $Rhs:ident
+            ]
+            $var:ident: $T:ident
+        })*]
+        []
+    ) => {
         impl_tuple_builder_fields! {
             {}
             [$({
@@ -337,6 +456,7 @@ macro_rules! impl_tuples {
         impl<$($T: Type,)*> Type for ($($T,)*) {
             type BaseType = Bundle;
             type MaskType = ($($T::MaskType,)*);
+            type SimValue = ($(SimValue<$T>,)*);
             type MatchVariant = ($(Expr<$T>,)*);
             type MatchActiveScope = ();
             type MatchVariantAndInactiveScope = MatchVariantWithoutScope<Self::MatchVariant>;
@@ -375,6 +495,24 @@ macro_rules! impl_tuples {
             fn source_location() -> SourceLocation {
                 SourceLocation::builtin()
             }
+            fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+                #![allow(unused_mut, unused_variables)]
+                let mut v = BundleSimValueFromBits::new(*self, bits);
+                $(let $var = v.field_from_bits();)*
+                ($($var,)*)
+            }
+            fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+                #![allow(unused_mut, unused_variables)]
+                let mut v = BundleSimValueFromBits::new(*self, bits);
+                let ($($var,)*) = value;
+                $(v.field_clone_from_bits($var);)*
+            }
+            fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+                #![allow(unused_mut, unused_variables)]
+                let mut v = BundleSimValueToBits::new(*self, bits);
+                let ($($var,)*) = value;
+                $(v.field_to_bits($var);)*
+            }
         }
         impl<$($T: Type,)*> BundleType for ($($T,)*) {
             type Builder = TupleBuilder<($(Unfilled<$T>,)*)>;
@@ -425,77 +563,104 @@ macro_rules! impl_tuples {
                 BundleLiteral::new(ty, field_values[..].intern()).to_expr()
             }
         }
-        impl<$($T: ToSimValue<CanonicalType>,)*> ToSimValue<CanonicalType> for ($($T,)*) {
+        impl<$($T: ToSimValueWithType<CanonicalType>,)*> ToSimValueWithType<CanonicalType> for ($($T,)*) {
             #[track_caller]
-            fn to_sim_value(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
-                ToSimValue::<Bundle>::to_sim_value(self, Bundle::from_canonical(ty)).into_canonical()
+            fn to_sim_value_with_type(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
+                SimValue::into_canonical(ToSimValueWithType::<Bundle>::to_sim_value_with_type(self, Bundle::from_canonical(ty)))
             }
             #[track_caller]
-            fn into_sim_value(self, ty: CanonicalType) -> SimValue<CanonicalType>
+            fn into_sim_value_with_type(self, ty: CanonicalType) -> SimValue<CanonicalType>
             {
-                ToSimValue::<Bundle>::into_sim_value(self, Bundle::from_canonical(ty)).into_canonical()
+                SimValue::into_canonical(ToSimValueWithType::<Bundle>::into_sim_value_with_type(self, Bundle::from_canonical(ty)))
             }
+        }
+        impl<$($T: ToSimValueWithType<CanonicalType>,)*> ToSimValueWithType<Bundle> for ($($T,)*) {
             #[track_caller]
-            fn box_into_sim_value(self: Box<Self>, ty: CanonicalType) -> SimValue<CanonicalType> {
-                ToSimValue::<Bundle>::box_into_sim_value(self, Bundle::from_canonical(ty)).into_canonical()
-            }
-        }
-        impl<$($T: ToSimValue<CanonicalType>,)*> ToSimValue<Bundle> for ($($T,)*) {
-            #[track_caller]
-            fn to_sim_value(&self, ty: Bundle) -> SimValue<Bundle> {
+            fn to_sim_value_with_type(&self, ty: Bundle) -> SimValue<Bundle> {
                 let ($($var,)*) = self;
                 let [$($ty_var,)*] = *ty.fields() else {
                     panic!("bundle has wrong number of fields");
                 };
-                $(let $var = $var.to_sim_value($ty_var.ty);)*
-                ToSimValue::into_sim_value(($($var,)*), ty)
+                $(let $var = $var.to_sim_value_with_type($ty_var.ty);)*
+                ToSimValueWithType::into_sim_value_with_type(($($var,)*), ty)
             }
             #[track_caller]
-            fn into_sim_value(self, ty: Bundle) -> SimValue<Bundle> {
+            fn into_sim_value_with_type(self, ty: Bundle) -> SimValue<Bundle> {
                 #![allow(unused_mut)]
                 #![allow(clippy::unused_unit)]
                 let ($($var,)*) = self;
                 let [$($ty_var,)*] = *ty.fields() else {
                     panic!("bundle has wrong number of fields");
                 };
-                let mut bits: Option<BitVec> = None;
-                $(let $var = $var.into_sim_value($ty_var.ty);
-                assert_eq!($var.ty(), $ty_var.ty);
-                if !$var.bits().is_empty() {
-                    if let Some(bits) = &mut bits {
-                        bits.extend_from_bitslice($var.bits());
-                    } else {
-                        let mut $var = $var.into_bits();
-                        $var.reserve(ty.type_properties().bit_width - $var.len());
-                        bits = Some($var);
-                    }
-                }
+                let mut bits = BitVec::new();
+                $(let $var = $var.into_sim_value_with_type($ty_var.ty);
+                assert_eq!(SimValue::ty(&$var), $ty_var.ty);
+                bits.extend_from_bitslice(SimValue::bits(&$var).bits());
                 )*
-                bits.unwrap_or_else(BitVec::new).into_sim_value(ty)
+                bits.into_sim_value_with_type(ty)
             }
+        }
+        impl<$($T: ToSimValueWithType<$Ty>, $Ty: Type,)*> ToSimValueWithType<($($Ty,)*)> for ($($T,)*) {
             #[track_caller]
-            fn box_into_sim_value(self: Box<Self>, ty: Bundle) -> SimValue<Bundle> {
-                Self::into_sim_value(*self, ty)
-            }
-        }
-        impl<$($T: ToSimValue<$Ty>, $Ty: Type,)*> ToSimValue<($($Ty,)*)> for ($($T,)*) {
-            #[track_caller]
-            fn to_sim_value(&self, ty: ($($Ty,)*)) -> SimValue<($($Ty,)*)> {
+            fn to_sim_value_with_type(&self, ty: ($($Ty,)*)) -> SimValue<($($Ty,)*)> {
                 let ($($var,)*) = self;
                 let ($($ty_var,)*) = ty;
-                $(let $var = $var.to_sim_value($ty_var).into_canonical();)*
-                SimValue::from_canonical(ToSimValue::into_sim_value(($($var,)*), ty.canonical()))
+                $(let $var = $var.to_sim_value_with_type($ty_var);)*
+                SimValue::from_value(ty, ($($var,)*))
             }
             #[track_caller]
-            fn into_sim_value(self, ty: ($($Ty,)*)) -> SimValue<($($Ty,)*)> {
+            fn into_sim_value_with_type(self, ty: ($($Ty,)*)) -> SimValue<($($Ty,)*)> {
                 let ($($var,)*) = self;
                 let ($($ty_var,)*) = ty;
-                $(let $var = $var.into_sim_value($ty_var).into_canonical();)*
-                SimValue::from_canonical(ToSimValue::into_sim_value(($($var,)*), ty.canonical()))
+                $(let $var = $var.into_sim_value_with_type($ty_var);)*
+                SimValue::from_value(ty, ($($var,)*))
+            }
+        }
+        impl<$($T: ToSimValue,)*> ToSimValue for ($($T,)*) {
+            type Type = ($($T::Type,)*);
+            #[track_caller]
+            fn to_sim_value(&self) -> SimValue<Self::Type> {
+                let ($($var,)*) = self;
+                $(let $var = $var.to_sim_value();)*
+                SimValue::from_value(($(SimValue::ty(&$var),)*), ($($var,)*))
             }
             #[track_caller]
-            fn box_into_sim_value(self: Box<Self>, ty: ($($Ty,)*)) -> SimValue<($($Ty,)*)> {
-                Self::into_sim_value(*self, ty)
+            fn into_sim_value(self) -> SimValue<Self::Type> {
+                let ($($var,)*) = self;
+                $(let $var = $var.to_sim_value();)*
+                SimValue::from_value(($(SimValue::ty(&$var),)*), ($($var,)*))
+            }
+        }
+        impl<$($Lhs: Type + ExprPartialEq<$Rhs>, $Rhs: Type,)*> ExprPartialEq<($($Rhs,)*)> for ($($Lhs,)*) {
+            fn cmp_eq(lhs: Expr<Self>, rhs: Expr<($($Rhs,)*)>) -> Expr<Bool> {
+                let ($($lhs_var,)*) = *lhs;
+                let ($($rhs_var,)*) = *rhs;
+                ArrayLiteral::<Bool, DynSize>::new(
+                    Bool,
+                    FromIterator::from_iter([$(Expr::canonical(ExprPartialEq::cmp_eq($lhs_var, $rhs_var)),)*]),
+                )
+                .cast_to_bits()
+                .all_one_bits()
+            }
+
+            fn cmp_ne(lhs: Expr<Self>, rhs: Expr<($($Rhs,)*)>) -> Expr<Bool> {
+                let ($($lhs_var,)*) = *lhs;
+                let ($($rhs_var,)*) = *rhs;
+                ArrayLiteral::<Bool, DynSize>::new(
+                    Bool,
+                    FromIterator::from_iter([$(Expr::canonical(ExprPartialEq::cmp_ne($lhs_var, $rhs_var)),)*]),
+                )
+                .cast_to_bits()
+                .any_one_bits()
+            }
+        }
+        impl<$($Lhs: SimValuePartialEq<$Rhs>, $Rhs: Type,)*> SimValuePartialEq<($($Rhs,)*)> for ($($Lhs,)*) {
+            fn sim_value_eq(lhs: &SimValue<Self>, rhs: &SimValue<($($Rhs,)*)>) -> bool {
+                let ($($lhs_var,)*) = &**lhs;
+                let ($($rhs_var,)*) = &**rhs;
+                let retval = true;
+                $(let retval = retval && $lhs_var == $rhs_var;)*
+                retval
             }
         }
     };
@@ -507,24 +672,25 @@ macro_rules! impl_tuples {
 
 impl_tuples! {
     [] [
-        {#[num = 0, field = field_0, ty = ty0: Ty0] v0: T0}
-        {#[num = 1, field = field_1, ty = ty1: Ty1] v1: T1}
-        {#[num = 2, field = field_2, ty = ty2: Ty2] v2: T2}
-        {#[num = 3, field = field_3, ty = ty3: Ty3] v3: T3}
-        {#[num = 4, field = field_4, ty = ty4: Ty4] v4: T4}
-        {#[num = 5, field = field_5, ty = ty5: Ty5] v5: T5}
-        {#[num = 6, field = field_6, ty = ty6: Ty6] v6: T6}
-        {#[num = 7, field = field_7, ty = ty7: Ty7] v7: T7}
-        {#[num = 8, field = field_8, ty = ty8: Ty8] v8: T8}
-        {#[num = 9, field = field_9, ty = ty9: Ty9] v9: T9}
-        {#[num = 10, field = field_10, ty = ty10: Ty10] v10: T10}
-        {#[num = 11, field = field_11, ty = ty11: Ty11] v11: T11}
+        {#[num = 0, field = field_0, ty = ty0: Ty0, lhs = lhs0: Lhs0, rhs = rhs0: Rhs0] v0: T0}
+        {#[num = 1, field = field_1, ty = ty1: Ty1, lhs = lhs1: Lhs1, rhs = rhs1: Rhs1] v1: T1}
+        {#[num = 2, field = field_2, ty = ty2: Ty2, lhs = lhs2: Lhs2, rhs = rhs2: Rhs2] v2: T2}
+        {#[num = 3, field = field_3, ty = ty3: Ty3, lhs = lhs3: Lhs3, rhs = rhs3: Rhs3] v3: T3}
+        {#[num = 4, field = field_4, ty = ty4: Ty4, lhs = lhs4: Lhs4, rhs = rhs4: Rhs4] v4: T4}
+        {#[num = 5, field = field_5, ty = ty5: Ty5, lhs = lhs5: Lhs5, rhs = rhs5: Rhs5] v5: T5}
+        {#[num = 6, field = field_6, ty = ty6: Ty6, lhs = lhs6: Lhs6, rhs = rhs6: Rhs6] v6: T6}
+        {#[num = 7, field = field_7, ty = ty7: Ty7, lhs = lhs7: Lhs7, rhs = rhs7: Rhs7] v7: T7}
+        {#[num = 8, field = field_8, ty = ty8: Ty8, lhs = lhs8: Lhs8, rhs = rhs8: Rhs8] v8: T8}
+        {#[num = 9, field = field_9, ty = ty9: Ty9, lhs = lhs9: Lhs9, rhs = rhs9: Rhs9] v9: T9}
+        {#[num = 10, field = field_10, ty = ty10: Ty10, lhs = lhs10: Lhs10, rhs = rhs10: Rhs10] v10: T10}
+        {#[num = 11, field = field_11, ty = ty11: Ty11, lhs = lhs11: Lhs11, rhs = rhs11: Rhs11] v11: T11}
     ]
 }
 
 impl<T: ?Sized + Send + Sync + 'static> Type for PhantomData<T> {
     type BaseType = Bundle;
     type MaskType = ();
+    type SimValue = PhantomData<T>;
     type MatchVariant = PhantomData<T>;
     type MatchActiveScope = ();
     type MatchVariantAndInactiveScope = MatchVariantWithoutScope<Self::MatchVariant>;
@@ -557,6 +723,16 @@ impl<T: ?Sized + Send + Sync + 'static> Type for PhantomData<T> {
     fn source_location() -> SourceLocation {
         SourceLocation::builtin()
     }
+    fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+        assert!(bits.is_empty());
+        *self
+    }
+    fn sim_value_clone_from_bits(&self, _value: &mut Self::SimValue, bits: &BitSlice) {
+        assert!(bits.is_empty());
+    }
+    fn sim_value_to_bits(&self, _value: &Self::SimValue, bits: &mut BitSlice) {
+        assert!(bits.is_empty());
+    }
 }
 
 pub struct PhantomDataBuilder<T: ?Sized + Send + Sync + 'static>(PhantomData<T>);
@@ -604,26 +780,38 @@ impl<T: ?Sized + Send + Sync + 'static> ToExpr for PhantomData<T> {
     }
 }
 
-impl<T: ?Sized + Send + Sync + 'static> ToSimValue<Self> for PhantomData<T> {
+impl<T: ?Sized + Send + Sync + 'static> ToSimValue for PhantomData<T> {
+    type Type = PhantomData<T>;
+
     #[track_caller]
-    fn to_sim_value(&self, ty: Self) -> SimValue<Self> {
-        ToSimValue::into_sim_value(BitVec::new(), ty)
+    fn to_sim_value(&self) -> SimValue<Self> {
+        SimValue::from_value(*self, *self)
     }
 }
 
-impl<T: ?Sized> ToSimValue<Bundle> for PhantomData<T> {
+impl<T: ?Sized + Send + Sync + 'static> ToSimValueWithType<Self> for PhantomData<T> {
     #[track_caller]
-    fn to_sim_value(&self, ty: Bundle) -> SimValue<Bundle> {
+    fn to_sim_value_with_type(&self, ty: Self) -> SimValue<Self> {
+        SimValue::from_value(ty, *self)
+    }
+}
+
+impl<T: ?Sized> ToSimValueWithType<Bundle> for PhantomData<T> {
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: Bundle) -> SimValue<Bundle> {
         assert!(ty.fields().is_empty());
-        ToSimValue::into_sim_value(BitVec::new(), ty)
+        ToSimValueWithType::into_sim_value_with_type(BitVec::new(), ty)
     }
 }
 
-impl<T: ?Sized> ToSimValue<CanonicalType> for PhantomData<T> {
+impl<T: ?Sized> ToSimValueWithType<CanonicalType> for PhantomData<T> {
     #[track_caller]
-    fn to_sim_value(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
+    fn to_sim_value_with_type(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
         let ty = Bundle::from_canonical(ty);
         assert!(ty.fields().is_empty());
-        ToSimValue::into_sim_value(BitVec::new(), ty).into_canonical()
+        SimValue::into_canonical(ToSimValueWithType::into_sim_value_with_type(
+            BitVec::new(),
+            ty,
+        ))
     }
 }

crates/fayalite/src/cli.rs

@@ -258,7 +258,7 @@ pub struct VerilogArgs {
         default_value = "firtool",
         env = "FIRTOOL",
         value_hint = ValueHint::CommandName,
-        value_parser = OsStringValueParser::new().try_map(which::which)
+        value_parser = OsStringValueParser::new().try_map(which)
     )]
     pub firtool: PathBuf,
     #[arg(long)]
@@ -428,6 +428,13 @@ impl clap::Args for FormalAdjustArgs {
     }
 }
 
+fn which(v: std::ffi::OsString) -> which::Result<PathBuf> {
+    #[cfg(not(miri))]
+    return which::which(v);
+    #[cfg(miri)]
+    return Ok(Path::new("/").join(v));
+}
+
 #[derive(Parser, Clone)]
 #[non_exhaustive]
 pub struct FormalArgs {
@@ -438,7 +445,7 @@ pub struct FormalArgs {
         default_value = "sby",
         env = "SBY",
         value_hint = ValueHint::CommandName,
-        value_parser = OsStringValueParser::new().try_map(which::which)
+        value_parser = OsStringValueParser::new().try_map(which)
     )]
     pub sby: PathBuf,
     #[arg(long)]

crates/fayalite/src/clock.rs

@@ -8,6 +8,7 @@ use crate::{
     source_location::SourceLocation,
     ty::{impl_match_variant_as_self, CanonicalType, StaticType, Type, TypeProperties},
 };
+use bitvec::slice::BitSlice;
 
 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug, Default)]
 pub struct Clock;
@@ -15,6 +16,7 @@ pub struct Clock;
 impl Type for Clock {
     type BaseType = Clock;
     type MaskType = Bool;
+    type SimValue = bool;
 
     impl_match_variant_as_self!();
 
@@ -36,6 +38,21 @@ impl Type for Clock {
         };
         retval
     }
+
+    fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+        assert_eq!(bits.len(), 1);
+        bits[0]
+    }
+
+    fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+        assert_eq!(bits.len(), 1);
+        *value = bits[0];
+    }
+
+    fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+        assert_eq!(bits.len(), 1);
+        bits.set(0, *value);
+    }
 }
 
 impl Clock {

crates/fayalite/src/enum_.rs

@@ -2,21 +2,30 @@
 // See Notices.txt for copyright information
 
 use crate::{
-    expr::{ops::VariantAccess, Expr, ToExpr},
+    expr::{
+        ops::{ExprPartialEq, VariantAccess},
+        Expr, ToExpr,
+    },
     hdl,
-    int::Bool,
+    int::{Bool, UIntValue},
     intern::{Intern, Interned},
     module::{
         connect, enum_match_variants_helper, incomplete_wire, wire,
         EnumMatchVariantAndInactiveScopeImpl, EnumMatchVariantsIterImpl, Scope,
     },
+    sim::value::{SimValue, SimValuePartialEq},
     source_location::SourceLocation,
-    ty::{CanonicalType, MatchVariantAndInactiveScope, StaticType, Type, TypeProperties},
+    ty::{
+        CanonicalType, MatchVariantAndInactiveScope, OpaqueSimValue, StaticType, Type,
+        TypeProperties,
+    },
+    util::HashMap,
 };
-use hashbrown::HashMap;
-use std::{convert::Infallible, fmt, iter::FusedIterator};
+use bitvec::{order::Lsb0, slice::BitSlice, view::BitView};
+use serde::{Deserialize, Serialize};
+use std::{convert::Infallible, fmt, iter::FusedIterator, sync::Arc};
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Serialize, Deserialize)]
 pub struct EnumVariant {
     pub name: Interned<str>,
     pub ty: Option<CanonicalType>,
@@ -149,6 +158,12 @@ impl EnumTypePropertiesBuilder {
             variant_count: variant_count + 1,
         }
     }
+    #[must_use]
+    pub fn variants(self, variants: impl IntoIterator<Item = EnumVariant>) -> Self {
+        variants.into_iter().fold(self, |this, variant| {
+            this.variant(variant.ty.map(CanonicalType::type_properties))
+        })
+    }
     pub const fn finish(self) -> TypeProperties {
         assert!(
             self.variant_count != 0,
@@ -178,7 +193,8 @@ impl Default for EnumTypePropertiesBuilder {
 impl Enum {
     #[track_caller]
     pub fn new(variants: Interned<[EnumVariant]>) -> Self {
-        let mut name_indexes = HashMap::with_capacity(variants.len());
+        let mut name_indexes =
+            HashMap::with_capacity_and_hasher(variants.len(), Default::default());
         let mut type_props_builder = EnumTypePropertiesBuilder::new();
         for (index, EnumVariant { name, ty }) in variants.iter().enumerate() {
             if let Some(old_index) = name_indexes.insert(*name, index) {
@@ -245,6 +261,7 @@ pub trait EnumType:
     MatchVariantsIter = EnumMatchVariantsIter<Self>,
 >
 {
+    type SimBuilder: From<Self>;
     fn variants(&self) -> Interned<[EnumVariant]>;
     fn match_activate_scope(
         v: Self::MatchVariantAndInactiveScope,
@@ -307,7 +324,18 @@ impl<T: EnumType> DoubleEndedIterator for EnumMatchVariantsIter<T> {
     }
 }
 
+pub struct NoBuilder {
+    _ty: Enum,
+}
+
+impl From<Enum> for NoBuilder {
+    fn from(_ty: Enum) -> Self {
+        Self { _ty }
+    }
+}
+
 impl EnumType for Enum {
+    type SimBuilder = NoBuilder;
     fn match_activate_scope(
         v: Self::MatchVariantAndInactiveScope,
     ) -> (Self::MatchVariant, Self::MatchActiveScope) {
@@ -322,6 +350,7 @@ impl EnumType for Enum {
 impl Type for Enum {
     type BaseType = Enum;
     type MaskType = Bool;
+    type SimValue = OpaqueSimValue;
     type MatchVariant = Option<Expr<CanonicalType>>;
     type MatchActiveScope = Scope;
     type MatchVariantAndInactiveScope = EnumMatchVariantAndInactiveScope<Self>;
@@ -352,6 +381,309 @@ impl Type for Enum {
     fn source_location() -> SourceLocation {
         SourceLocation::builtin()
     }
+    fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+        assert_eq!(bits.len(), self.type_properties().bit_width);
+        OpaqueSimValue::from_bitslice(bits)
+    }
+    fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+        assert_eq!(bits.len(), self.type_properties().bit_width);
+        assert_eq!(value.bit_width(), self.type_properties().bit_width);
+        value.bits_mut().bits_mut().copy_from_bitslice(bits);
+    }
+    fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+        assert_eq!(bits.len(), self.type_properties().bit_width);
+        assert_eq!(value.bit_width(), self.type_properties().bit_width);
+        bits.copy_from_bitslice(value.bits().bits());
+    }
+}
+
+#[derive(Clone, PartialEq, Eq, Hash, Debug, Default)]
+pub struct EnumPaddingSimValue {
+    bits: Option<UIntValue>,
+}
+
+impl EnumPaddingSimValue {
+    pub const fn new() -> Self {
+        Self { bits: None }
+    }
+    pub fn bit_width(&self) -> Option<usize> {
+        self.bits.as_ref().map(UIntValue::width)
+    }
+    pub fn bits(&self) -> &Option<UIntValue> {
+        &self.bits
+    }
+    pub fn bits_mut(&mut self) -> &mut Option<UIntValue> {
+        &mut self.bits
+    }
+    pub fn into_bits(self) -> Option<UIntValue> {
+        self.bits
+    }
+    pub fn from_bits(bits: Option<UIntValue>) -> Self {
+        Self { bits }
+    }
+    pub fn from_bitslice(v: &BitSlice) -> Self {
+        Self {
+            bits: Some(UIntValue::new(Arc::new(v.to_bitvec()))),
+        }
+    }
+}
+
+#[derive(Clone, PartialEq, Eq, Hash, Debug)]
+pub struct UnknownVariantSimValue {
+    discriminant: usize,
+    body_bits: UIntValue,
+}
+
+impl UnknownVariantSimValue {
+    pub fn discriminant(&self) -> usize {
+        self.discriminant
+    }
+    pub fn body_bits(&self) -> &UIntValue {
+        &self.body_bits
+    }
+    pub fn body_bits_mut(&mut self) -> &mut UIntValue {
+        &mut self.body_bits
+    }
+    pub fn into_body_bits(self) -> UIntValue {
+        self.body_bits
+    }
+    pub fn into_parts(self) -> (usize, UIntValue) {
+        (self.discriminant, self.body_bits)
+    }
+    pub fn new(discriminant: usize, body_bits: UIntValue) -> Self {
+        Self {
+            discriminant,
+            body_bits,
+        }
+    }
+}
+
+pub struct EnumSimValueFromBits<'a> {
+    variants: Interned<[EnumVariant]>,
+    discriminant: usize,
+    body_bits: &'a BitSlice,
+}
+
+impl<'a> EnumSimValueFromBits<'a> {
+    #[track_caller]
+    pub fn new<T: EnumType>(ty: T, bits: &'a BitSlice) -> Self {
+        let variants = ty.variants();
+        let bit_width = EnumTypePropertiesBuilder::new()
+            .variants(variants)
+            .finish()
+            .bit_width;
+        assert_eq!(bit_width, bits.len());
+        let (discriminant_bits, body_bits) =
+            bits.split_at(discriminant_bit_width_impl(variants.len()));
+        let mut discriminant = 0usize;
+        discriminant.view_bits_mut::<Lsb0>()[..discriminant_bits.len()]
+            .copy_from_bitslice(discriminant_bits);
+        Self {
+            variants,
+            discriminant,
+            body_bits,
+        }
+    }
+    pub fn discriminant(&self) -> usize {
+        self.discriminant
+    }
+    #[track_caller]
+    #[cold]
+    fn usage_error(&self, clone: bool) -> ! {
+        let clone = if clone { "clone_" } else { "" };
+        match self.variants.get(self.discriminant) {
+            None => {
+                panic!("should have called EnumSimValueFromBits::unknown_variant_{clone}from_bits");
+            }
+            Some(EnumVariant { ty: None, .. }) => {
+                panic!(
+                    "should have called EnumSimValueFromBits::variant_no_field_{clone}from_bits"
+                );
+            }
+            Some(EnumVariant { ty: Some(_), .. }) => {
+                panic!(
+                    "should have called EnumSimValueFromBits::variant_with_field_{clone}from_bits"
+                );
+            }
+        }
+    }
+    #[track_caller]
+    fn known_variant(&self, clone: bool) -> (Option<CanonicalType>, &'a BitSlice, &'a BitSlice) {
+        let Some(EnumVariant { ty, .. }) = self.variants.get(self.discriminant) else {
+            self.usage_error(clone);
+        };
+        let variant_bit_width = ty.map_or(0, CanonicalType::bit_width);
+        let (variant_bits, padding_bits) = self.body_bits.split_at(variant_bit_width);
+        (*ty, variant_bits, padding_bits)
+    }
+    #[track_caller]
+    pub fn unknown_variant_from_bits(self) -> UnknownVariantSimValue {
+        let None = self.variants.get(self.discriminant) else {
+            self.usage_error(false);
+        };
+        UnknownVariantSimValue::new(
+            self.discriminant,
+            UIntValue::new(Arc::new(self.body_bits.to_bitvec())),
+        )
+    }
+    #[track_caller]
+    pub fn unknown_variant_clone_from_bits(self, value: &mut UnknownVariantSimValue) {
+        let None = self.variants.get(self.discriminant) else {
+            self.usage_error(true);
+        };
+        value.discriminant = self.discriminant;
+        assert_eq!(value.body_bits.width(), self.body_bits.len());
+        value
+            .body_bits
+            .bits_mut()
+            .copy_from_bitslice(self.body_bits);
+    }
+    #[track_caller]
+    pub fn variant_no_field_from_bits(self) -> EnumPaddingSimValue {
+        let (None, _variant_bits, padding_bits) = self.known_variant(false) else {
+            self.usage_error(false);
+        };
+        EnumPaddingSimValue::from_bitslice(padding_bits)
+    }
+    #[track_caller]
+    pub fn variant_with_field_from_bits<T: Type>(self) -> (SimValue<T>, EnumPaddingSimValue) {
+        let (Some(variant_ty), variant_bits, padding_bits) = self.known_variant(false) else {
+            self.usage_error(false);
+        };
+        (
+            SimValue::from_bitslice(T::from_canonical(variant_ty), variant_bits),
+            EnumPaddingSimValue::from_bitslice(padding_bits),
+        )
+    }
+    #[track_caller]
+    fn clone_padding_from_bits(padding: &mut EnumPaddingSimValue, padding_bits: &BitSlice) {
+        match padding.bits_mut() {
+            None => *padding = EnumPaddingSimValue::from_bitslice(padding_bits),
+            Some(padding) => {
+                assert_eq!(padding.width(), padding_bits.len());
+                padding.bits_mut().copy_from_bitslice(padding_bits);
+            }
+        }
+    }
+    #[track_caller]
+    pub fn variant_no_field_clone_from_bits(self, padding: &mut EnumPaddingSimValue) {
+        let (None, _variant_bits, padding_bits) = self.known_variant(true) else {
+            self.usage_error(true);
+        };
+        Self::clone_padding_from_bits(padding, padding_bits);
+    }
+    #[track_caller]
+    pub fn variant_with_field_clone_from_bits<T: Type>(
+        self,
+        value: &mut SimValue<T>,
+        padding: &mut EnumPaddingSimValue,
+    ) {
+        let (Some(variant_ty), variant_bits, padding_bits) = self.known_variant(true) else {
+            self.usage_error(true);
+        };
+        assert_eq!(SimValue::ty(value), T::from_canonical(variant_ty));
+        SimValue::bits_mut(value)
+            .bits_mut()
+            .copy_from_bitslice(variant_bits);
+        Self::clone_padding_from_bits(padding, padding_bits);
+    }
+}
+
+pub struct EnumSimValueToBits<'a> {
+    variants: Interned<[EnumVariant]>,
+    bit_width: usize,
+    discriminant_bit_width: usize,
+    bits: &'a mut BitSlice,
+}
+
+impl<'a> EnumSimValueToBits<'a> {
+    #[track_caller]
+    pub fn new<T: EnumType>(ty: T, bits: &'a mut BitSlice) -> Self {
+        let variants = ty.variants();
+        let bit_width = EnumTypePropertiesBuilder::new()
+            .variants(variants)
+            .finish()
+            .bit_width;
+        assert_eq!(bit_width, bits.len());
+        Self {
+            variants,
+            bit_width,
+            discriminant_bit_width: discriminant_bit_width_impl(variants.len()),
+            bits,
+        }
+    }
+    #[track_caller]
+    fn discriminant_to_bits(&mut self, mut discriminant: usize) {
+        let orig_discriminant = discriminant;
+        let discriminant_bits =
+            &mut discriminant.view_bits_mut::<Lsb0>()[..self.discriminant_bit_width];
+        self.bits[..self.discriminant_bit_width].copy_from_bitslice(discriminant_bits);
+        discriminant_bits.fill(false);
+        assert!(
+            discriminant == 0,
+            "{orig_discriminant:#x} is too big to fit in enum discriminant bits",
+        );
+    }
+    #[track_caller]
+    pub fn unknown_variant_to_bits(mut self, value: &UnknownVariantSimValue) {
+        self.discriminant_to_bits(value.discriminant);
+        let None = self.variants.get(value.discriminant) else {
+            panic!("can't use UnknownVariantSimValue to set known discriminant");
+        };
+        assert_eq!(
+            self.bit_width - self.discriminant_bit_width,
+            value.body_bits.width()
+        );
+        self.bits[self.discriminant_bit_width..].copy_from_bitslice(value.body_bits.bits());
+    }
+    #[track_caller]
+    fn known_variant(
+        mut self,
+        discriminant: usize,
+        padding: &EnumPaddingSimValue,
+    ) -> (Option<CanonicalType>, &'a mut BitSlice) {
+        self.discriminant_to_bits(discriminant);
+        let variant_ty = self.variants[discriminant].ty;
+        let variant_bit_width = variant_ty.map_or(0, CanonicalType::bit_width);
+        let padding_bits = &mut self.bits[self.discriminant_bit_width..][variant_bit_width..];
+        if let Some(padding) = padding.bits() {
+            assert_eq!(padding.width(), padding_bits.len());
+            padding_bits.copy_from_bitslice(padding.bits());
+        } else {
+            padding_bits.fill(false);
+        }
+        let variant_bits = &mut self.bits[self.discriminant_bit_width..][..variant_bit_width];
+        (variant_ty, variant_bits)
+    }
+    #[track_caller]
+    pub fn variant_no_field_to_bits(self, discriminant: usize, padding: &EnumPaddingSimValue) {
+        let (None, _variant_bits) = self.known_variant(discriminant, padding) else {
+            panic!("expected variant to have no field");
+        };
+    }
+    #[track_caller]
+    pub fn variant_with_field_to_bits<T: Type>(
+        self,
+        discriminant: usize,
+        value: &SimValue<T>,
+        padding: &EnumPaddingSimValue,
+    ) {
+        let (Some(variant_ty), variant_bits) = self.known_variant(discriminant, padding) else {
+            panic!("expected variant to have a field");
+        };
+        assert_eq!(SimValue::ty(value), T::from_canonical(variant_ty));
+        variant_bits.copy_from_bitslice(SimValue::bits(value).bits());
+    }
+}
+
+#[doc(hidden)]
+pub fn assert_is_enum_type<T: EnumType>(v: T) -> T {
+    v
+}
+
+#[doc(hidden)]
+pub fn enum_type_to_sim_builder<T: EnumType>(v: T) -> T::SimBuilder {
+    v.into()
 }
 
 #[hdl]
@@ -360,6 +692,79 @@ pub enum HdlOption<T: Type> {
     HdlSome(T),
 }
 
+impl<Lhs: Type + ExprPartialEq<Rhs>, Rhs: Type> ExprPartialEq<HdlOption<Rhs>> for HdlOption<Lhs> {
+    #[hdl]
+    fn cmp_eq(lhs: Expr<Self>, rhs: Expr<HdlOption<Rhs>>) -> Expr<Bool> {
+        #[hdl]
+        let cmp_eq = wire();
+        #[hdl]
+        match lhs {
+            HdlSome(lhs) =>
+            {
+                #[hdl]
+                match rhs {
+                    HdlSome(rhs) => connect(cmp_eq, ExprPartialEq::cmp_eq(lhs, rhs)),
+                    HdlNone => connect(cmp_eq, false),
+                }
+            }
+            HdlNone =>
+            {
+                #[hdl]
+                match rhs {
+                    HdlSome(_) => connect(cmp_eq, false),
+                    HdlNone => connect(cmp_eq, true),
+                }
+            }
+        }
+        cmp_eq
+    }
+
+    #[hdl]
+    fn cmp_ne(lhs: Expr<Self>, rhs: Expr<HdlOption<Rhs>>) -> Expr<Bool> {
+        #[hdl]
+        let cmp_ne = wire();
+        #[hdl]
+        match lhs {
+            HdlSome(lhs) =>
+            {
+                #[hdl]
+                match rhs {
+                    HdlSome(rhs) => connect(cmp_ne, ExprPartialEq::cmp_ne(lhs, rhs)),
+                    HdlNone => connect(cmp_ne, true),
+                }
+            }
+            HdlNone =>
+            {
+                #[hdl]
+                match rhs {
+                    HdlSome(_) => connect(cmp_ne, true),
+                    HdlNone => connect(cmp_ne, false),
+                }
+            }
+        }
+        cmp_ne
+    }
+}
+
+impl<Lhs: SimValuePartialEq<Rhs>, Rhs: Type> SimValuePartialEq<HdlOption<Rhs>> for HdlOption<Lhs> {
+    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<HdlOption<Rhs>>) -> bool {
+        type SimValueMatch<T> = <T as Type>::SimValue;
+        match (&**this, &**other) {
+            (SimValueMatch::<Self>::HdlNone(_), SimValueMatch::<HdlOption<Rhs>>::HdlNone(_)) => {
+                true
+            }
+            (SimValueMatch::<Self>::HdlSome(..), SimValueMatch::<HdlOption<Rhs>>::HdlNone(_))
+            | (SimValueMatch::<Self>::HdlNone(_), SimValueMatch::<HdlOption<Rhs>>::HdlSome(..)) => {
+                false
+            }
+            (
+                SimValueMatch::<Self>::HdlSome(l, _),
+                SimValueMatch::<HdlOption<Rhs>>::HdlSome(r, _),
+            ) => l == r,
+        }
+    }
+}
+
 #[allow(non_snake_case)]
 pub fn HdlNone<T: StaticType>() -> Expr<HdlOption<T>> {
     HdlOption[T::TYPE].HdlNone()

crates/fayalite/src/expr.rs

@@ -16,6 +16,7 @@ use crate::{
         transform::visit::{Fold, Folder, Visit, Visitor},
         Instance, ModuleIO,
     },
+    phantom_const::PhantomConst,
     reg::Reg,
     reset::{AsyncReset, Reset, ResetType, ResetTypeDispatch, SyncReset},
     ty::{CanonicalType, StaticType, Type, TypeWithDeref},
@@ -109,6 +110,7 @@ expr_enum! {
         UIntLiteral(Interned<UIntValue>),
         SIntLiteral(Interned<SIntValue>),
         BoolLiteral(bool),
+        PhantomConst(PhantomConst),
         BundleLiteral(ops::BundleLiteral),
         ArrayLiteral(ops::ArrayLiteral<CanonicalType, DynSize>),
         EnumLiteral(ops::EnumLiteral),
@@ -272,6 +274,17 @@ pub struct Expr<T: Type> {
 
 impl<T: Type + fmt::Debug> fmt::Debug for Expr<T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        #[cfg(debug_assertions)]
+        {
+            let Self {
+                __enum,
+                __ty,
+                __flow,
+            } = self;
+            let expr_ty = __ty.canonical();
+            let enum_ty = __enum.to_expr().__ty;
+            assert_eq!(expr_ty, enum_ty, "expr ty mismatch:\nExpr {{\n__enum: {__enum:?},\n__ty: {__ty:?},\n__flow: {__flow:?}\n}}");
+        }
         self.__enum.fmt(f)
     }
 }
@@ -698,6 +711,7 @@ impl<T: ToExpr + ?Sized> CastToBits for T {
 }
 
 pub trait CastBitsTo {
+    #[track_caller]
     fn cast_bits_to<T: Type>(&self, ty: T) -> Expr<T>;
 }
 
@@ -755,3 +769,27 @@ pub fn repeat<T: Type, L: SizeType>(
     )
     .to_expr()
 }
+
+impl<T: ?Sized + crate::phantom_const::PhantomConstValue> ToExpr for PhantomConst<T> {
+    type Type = Self;
+
+    fn to_expr(&self) -> Expr<Self::Type> {
+        Expr {
+            __enum: ExprEnum::PhantomConst(self.canonical_phantom_const()).intern_sized(),
+            __ty: *self,
+            __flow: Flow::Source,
+        }
+    }
+}
+
+impl<T: ?Sized + crate::phantom_const::PhantomConstValue> GetTarget for PhantomConst<T> {
+    fn target(&self) -> Option<Interned<Target>> {
+        None
+    }
+}
+
+impl<T: ?Sized + crate::phantom_const::PhantomConstValue> ToLiteralBits for PhantomConst<T> {
+    fn to_literal_bits(&self) -> Result<Interned<BitSlice>, NotALiteralExpr> {
+        Ok(Interned::default())
+    }
+}

crates/fayalite/src/expr/ops.rs

@@ -11,14 +11,15 @@ use crate::{
             GetTarget, Target, TargetPathArrayElement, TargetPathBundleField,
             TargetPathDynArrayElement, TargetPathElement,
         },
-        CastTo, Expr, ExprEnum, Flow, HdlPartialEq, HdlPartialOrd, NotALiteralExpr, ReduceBits,
-        ToExpr, ToLiteralBits,
+        CastBitsTo as _, CastTo, CastToBits as _, Expr, ExprEnum, Flow, HdlPartialEq,
+        HdlPartialOrd, NotALiteralExpr, ReduceBits, ToExpr, ToLiteralBits,
     },
     int::{
         Bool, BoolOrIntType, DynSize, IntType, KnownSize, SInt, SIntType, SIntValue, Size, UInt,
         UIntType, UIntValue,
     },
     intern::{Intern, Interned},
+    phantom_const::{PhantomConst, PhantomConstValue},
     reset::{
         AsyncReset, Reset, ResetType, ResetTypeDispatch, SyncReset, ToAsyncReset, ToReset,
         ToSyncReset,
@@ -1892,6 +1893,26 @@ impl ExprCastTo<Clock> for Clock {
     }
 }
 
+impl<T: ?Sized + PhantomConstValue> ExprCastTo<()> for PhantomConst<T> {
+    fn cast_to(src: Expr<Self>, to_type: ()) -> Expr<()> {
+        src.cast_to_bits().cast_bits_to(to_type)
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> ExprCastTo<PhantomConst<T>> for () {
+    fn cast_to(src: Expr<Self>, to_type: PhantomConst<T>) -> Expr<PhantomConst<T>> {
+        src.cast_to_bits().cast_bits_to(to_type)
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue, U: ?Sized + PhantomConstValue> ExprCastTo<PhantomConst<T>>
+    for PhantomConst<U>
+{
+    fn cast_to(src: Expr<Self>, to_type: PhantomConst<T>) -> Expr<PhantomConst<T>> {
+        src.cast_to_bits().cast_bits_to(to_type)
+    }
+}
+
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
 pub struct FieldAccess<FieldType: Type = CanonicalType> {
     base: Expr<Bundle>,
@@ -2708,3 +2729,47 @@ impl<T: Type> ToExpr for Uninit<T> {
         }
     }
 }
+
+pub trait ExprIntoIterator: Type {
+    type Item: Type;
+    type ExprIntoIter: Iterator<Item = Expr<Self::Item>>;
+
+    fn expr_into_iter(e: Expr<Self>) -> Self::ExprIntoIter;
+}
+
+impl<T: ExprIntoIterator> IntoIterator for Expr<T> {
+    type Item = Expr<T::Item>;
+    type IntoIter = T::ExprIntoIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        T::expr_into_iter(self)
+    }
+}
+
+impl<T: ExprIntoIterator> IntoIterator for &'_ Expr<T> {
+    type Item = Expr<T::Item>;
+    type IntoIter = T::ExprIntoIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        T::expr_into_iter(*self)
+    }
+}
+
+impl<T: ExprIntoIterator> IntoIterator for &'_ mut Expr<T> {
+    type Item = Expr<T::Item>;
+    type IntoIter = T::ExprIntoIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        T::expr_into_iter(*self)
+    }
+}
+
+pub trait ExprFromIterator<A>: Type {
+    fn expr_from_iter<T: IntoIterator<Item = A>>(iter: T) -> Expr<Self>;
+}
+
+impl<This: ExprFromIterator<A>, A> FromIterator<A> for Expr<This> {
+    fn from_iter<T: IntoIterator<Item = A>>(iter: T) -> Self {
+        This::expr_from_iter(iter)
+    }
+}

crates/fayalite/src/firrtl.rs

@@ -15,7 +15,7 @@ use crate::{
         target::{
             Target, TargetBase, TargetPathArrayElement, TargetPathBundleField, TargetPathElement,
         },
-        Expr, ExprEnum,
+        CastBitsTo, Expr, ExprEnum,
     },
     formal::FormalKind,
     int::{Bool, DynSize, IntType, SIntValue, UInt, UIntValue},
@@ -36,12 +36,11 @@ use crate::{
     ty::{CanonicalType, Type},
     util::{
         const_str_array_is_strictly_ascending, BitSliceWriteWithBase, DebugAsRawString,
-        GenericConstBool,
+        GenericConstBool, HashMap, HashSet,
     },
 };
 use bitvec::slice::BitSlice;
 use clap::value_parser;
-use hashbrown::{HashMap, HashSet};
 use num_traits::Signed;
 use serde::Serialize;
 use std::{
@@ -447,6 +446,7 @@ impl TypeState {
             CanonicalType::AsyncReset(AsyncReset {}) => "AsyncReset".into(),
             CanonicalType::SyncReset(SyncReset {}) => "UInt<1>".into(),
             CanonicalType::Reset(Reset {}) => "Reset".into(),
+            CanonicalType::PhantomConst(_) => "{}".into(),
         }
     }
 }
@@ -1152,6 +1152,7 @@ impl<'a> Exporter<'a> {
             | CanonicalType::Clock(_)
             | CanonicalType::AsyncReset(_)
             | CanonicalType::Reset(_) => format!("asUInt({value_str})"),
+            CanonicalType::PhantomConst(_) => "UInt<0>(0)".into(),
         }
     }
     fn expr_cast_bits_to_bundle(
@@ -1357,6 +1358,12 @@ impl<'a> Exporter<'a> {
             CanonicalType::AsyncReset(_) => format!("asAsyncReset({value_str})"),
             CanonicalType::SyncReset(_) => value_str,
             CanonicalType::Reset(_) => unreachable!("Reset is not bit castable to"),
+            CanonicalType::PhantomConst(_) => {
+                let retval = self.module.ns.make_new("_cast_bits_to_phantom_const_expr");
+                definitions.add_definition_line(format_args!("{extra_indent}wire {retval}: {{}}"));
+                definitions.add_definition_line(format_args!("{extra_indent}invalidate {retval}"));
+                return retval.to_string();
+            }
         }
     }
     fn expr_unary<T: Type>(
@@ -1395,6 +1402,11 @@ impl<'a> Exporter<'a> {
             ExprEnum::UIntLiteral(literal) => self.uint_literal(&literal),
             ExprEnum::SIntLiteral(literal) => self.sint_literal(&literal),
             ExprEnum::BoolLiteral(literal) => self.bool_literal(literal),
+            ExprEnum::PhantomConst(ty) => self.expr(
+                UInt[0].zero().cast_bits_to(ty.canonical()),
+                definitions,
+                const_ty,
+            ),
             ExprEnum::ArrayLiteral(array_literal) => {
                 self.array_literal_expr(array_literal, definitions, const_ty)
             }
@@ -2245,6 +2257,7 @@ impl<'a> Exporter<'a> {
             ModuleBody::Extern(ExternModuleBody {
                 verilog_name,
                 parameters,
+                simulation: _,
             }) => {
                 let verilog_name = Ident(verilog_name);
                 writeln!(body, "{indent}defname = {verilog_name}").unwrap();
@@ -2608,7 +2621,7 @@ fn export_impl(
             indent_depth: &indent_depth,
             indent: "    ",
         },
-        seen_modules: HashSet::new(),
+        seen_modules: HashSet::default(),
         unwritten_modules: VecDeque::new(),
         global_ns,
         module: ModuleState::default(),

crates/fayalite/src/int.rs

@@ -2,27 +2,52 @@
 // See Notices.txt for copyright information
 
 use crate::{
+    array::ArrayType,
     expr::{
         target::{GetTarget, Target},
         Expr, NotALiteralExpr, ToExpr, ToLiteralBits,
     },
+    hdl,
     intern::{Intern, Interned, Memoize},
+    sim::value::{SimValue, ToSimValueWithType},
     source_location::SourceLocation,
     ty::{impl_match_variant_as_self, CanonicalType, StaticType, Type, TypeProperties},
     util::{interned_bit, ConstBool, ConstUsize, GenericConstBool, GenericConstUsize},
 };
-use bitvec::{order::Lsb0, slice::BitSlice, vec::BitVec};
+use bitvec::{order::Lsb0, slice::BitSlice, vec::BitVec, view::BitView};
 use num_bigint::{BigInt, BigUint, Sign};
-use num_traits::{Signed, Zero};
+use num_traits::{One, Signed, Zero};
+use serde::{
+    de::{DeserializeOwned, Error, Visitor},
+    Deserialize, Deserializer, Serialize, Serializer,
+};
 use std::{
     borrow::{BorrowMut, Cow},
     fmt,
     marker::PhantomData,
     num::NonZero,
     ops::{Bound, Index, Not, Range, RangeBounds, RangeInclusive},
+    str::FromStr,
     sync::Arc,
 };
 
+mod uint_in_range;
+
+#[hdl]
+pub type UIntInRangeType<Start: Size, End: Size> = uint_in_range::UIntInRangeType<Start, End>;
+
+#[hdl]
+pub type UIntInRange<const START: usize, const END: usize> =
+    UIntInRangeType<ConstUsize<START>, ConstUsize<END>>;
+
+#[hdl]
+pub type UIntInRangeInclusiveType<Start: Size, End: Size> =
+    uint_in_range::UIntInRangeInclusiveType<Start, End>;
+
+#[hdl]
+pub type UIntInRangeInclusive<const START: usize, const END: usize> =
+    UIntInRangeInclusiveType<ConstUsize<START>, ConstUsize<END>>;
+
 mod sealed {
     pub trait BoolOrIntTypeSealed {}
     pub trait SizeSealed {}
@@ -49,6 +74,16 @@ pub trait KnownSize:
         + IntoIterator<Item = Expr<Element>>
         + TryFrom<Vec<Expr<Element>>>
         + Into<Vec<Expr<Element>>>;
+    type ArraySimValue<Element: Type>: AsRef<[SimValue<Element>]>
+        + AsMut<[SimValue<Element>]>
+        + BorrowMut<[SimValue<Element>]>
+        + 'static
+        + Clone
+        + std::fmt::Debug
+        + IntoIterator<Item = SimValue<Element>>
+        + TryFrom<Vec<SimValue<Element>>>
+        + Into<Vec<SimValue<Element>>>
+        + ToSimValueWithType<ArrayType<Element, Self>>;
 }
 
 macro_rules! known_widths {
@@ -60,6 +95,7 @@ macro_rules! known_widths {
         }> {
             const SIZE: Self = Self;
             type ArrayMatch<Element: Type> = [Expr<Element>; Self::VALUE];
+            type ArraySimValue<Element: Type> = [SimValue<Element>; Self::VALUE];
         }
     };
     ([2 $($rest:tt)*] $($bits:literal)+) => {
@@ -72,6 +108,7 @@ macro_rules! known_widths {
         impl KnownSize for ConstUsize<{2 $(* $rest)*}> {
             const SIZE: Self = Self;
             type ArrayMatch<Element: Type> = [Expr<Element>; Self::VALUE];
+            type ArraySimValue<Element: Type> = [SimValue<Element>; Self::VALUE];
         }
     };
 }
@@ -79,13 +116,31 @@ macro_rules! known_widths {
 known_widths!([2 2 2 2 2 2 2 2 2]);
 
 pub trait SizeType:
-    sealed::SizeTypeSealed + Copy + Ord + std::hash::Hash + std::fmt::Debug + Send + Sync + 'static
+    sealed::SizeTypeSealed
+    + Copy
+    + Ord
+    + std::hash::Hash
+    + std::fmt::Debug
+    + Send
+    + Sync
+    + 'static
+    + Serialize
+    + DeserializeOwned
 {
     type Size: Size<SizeType = Self>;
 }
 
 pub trait Size:
-    sealed::SizeSealed + Copy + Ord + std::hash::Hash + std::fmt::Debug + Send + Sync + 'static
+    sealed::SizeSealed
+    + Copy
+    + Ord
+    + std::hash::Hash
+    + std::fmt::Debug
+    + Send
+    + Sync
+    + 'static
+    + Serialize
+    + DeserializeOwned
 {
     type ArrayMatch<Element: Type>: AsRef<[Expr<Element>]>
         + AsMut<[Expr<Element>]>
@@ -100,6 +155,16 @@ pub trait Size:
         + IntoIterator<Item = Expr<Element>>
         + TryFrom<Vec<Expr<Element>>>
         + Into<Vec<Expr<Element>>>;
+    type ArraySimValue<Element: Type>: AsRef<[SimValue<Element>]>
+        + AsMut<[SimValue<Element>]>
+        + BorrowMut<[SimValue<Element>]>
+        + 'static
+        + Clone
+        + std::fmt::Debug
+        + IntoIterator<Item = SimValue<Element>>
+        + TryFrom<Vec<SimValue<Element>>>
+        + Into<Vec<SimValue<Element>>>
+        + ToSimValueWithType<ArrayType<Element, Self>>;
     const KNOWN_VALUE: Option<usize>;
     type SizeType: SizeType<Size = Self>
         + Copy
@@ -125,6 +190,7 @@ impl SizeType for usize {
 
 impl Size for DynSize {
     type ArrayMatch<Element: Type> = Box<[Expr<Element>]>;
+    type ArraySimValue<Element: Type> = Box<[SimValue<Element>]>;
     const KNOWN_VALUE: Option<usize> = None;
     type SizeType = usize;
 
@@ -147,6 +213,7 @@ impl<T: KnownSize> SizeType for T {
 
 impl<T: KnownSize> Size for T {
     type ArrayMatch<Element: Type> = <T as KnownSize>::ArrayMatch<Element>;
+    type ArraySimValue<Element: Type> = <T as KnownSize>::ArraySimValue<Element>;
 
     const KNOWN_VALUE: Option<usize> = Some(T::VALUE);
 
@@ -165,6 +232,305 @@ impl<T: KnownSize> Size for T {
     }
 }
 
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub enum ParseIntValueError {
+    Empty,
+    InvalidDigit,
+    MissingDigits,
+    InvalidRadix,
+    MissingType,
+    InvalidType,
+    TypeMismatch {
+        parsed_signed: bool,
+        parsed_width: usize,
+        expected_signed: bool,
+        expected_width: usize,
+    },
+    PosOverflow,
+    NegOverflow,
+    WidthOverflow,
+    MissingWidth,
+}
+
+impl std::error::Error for ParseIntValueError {}
+
+impl fmt::Display for ParseIntValueError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(match self {
+            Self::Empty => "can't parse integer from empty string",
+            Self::InvalidDigit => "invalid digit",
+            Self::MissingDigits => "missing digits",
+            Self::InvalidRadix => "invalid radix",
+            Self::MissingType => "missing type",
+            Self::InvalidType => "invalid type",
+            Self::TypeMismatch {
+                parsed_signed,
+                parsed_width,
+                expected_signed,
+                expected_width,
+            } => {
+                return write!(
+                    f,
+                    "type mismatch: parsed type {parsed_signed_str}{parsed_width}, \
+                    expected type {expected_signed_str}{expected_width}",
+                    parsed_signed_str = if *parsed_signed { "i" } else { "u" },
+                    expected_signed_str = if *expected_signed { "i" } else { "u" },
+                );
+            }
+            Self::PosOverflow => "value too large to fit in type",
+            Self::NegOverflow => "value too small to fit in type",
+            Self::WidthOverflow => "width is too large",
+            Self::MissingWidth => "missing width",
+        })
+    }
+}
+
+fn parse_int_value(
+    s: &str,
+    type_is_signed: bool,
+    type_width: Option<usize>,
+    parse_type: bool,
+) -> Result<Arc<BitVec>, ParseIntValueError> {
+    if !parse_type && type_width.is_none() {
+        return Err(ParseIntValueError::MissingWidth);
+    }
+    let mut s = s.trim();
+    if s.is_empty() {
+        return Err(ParseIntValueError::Empty);
+    }
+    let negative = match s.bytes().next() {
+        Some(ch @ (b'+' | b'-')) => {
+            s = s[1..].trim_start();
+            ch == b'-'
+        }
+        _ => false,
+    };
+    let radix = match s.bytes().next() {
+        Some(b'0') => match s.bytes().nth(1) {
+            Some(b'x' | b'X') => {
+                s = &s[2..];
+                16
+            }
+            Some(b'b' | b'B') => {
+                s = &s[2..];
+                2
+            }
+            Some(b'o' | b'O') => {
+                s = &s[2..];
+                8
+            }
+            _ => 10,
+        },
+        Some(b'1'..=b'9') => 10,
+        _ => return Err(ParseIntValueError::InvalidDigit),
+    };
+    let mut any_digits = false;
+    let digits_end = s
+        .as_bytes()
+        .iter()
+        .position(|&ch| {
+            if ch == b'_' {
+                false
+            } else if (ch as char).to_digit(radix).is_some() {
+                any_digits = true;
+                false
+            } else {
+                true
+            }
+        })
+        .unwrap_or(s.len());
+    let digits = &s[..digits_end];
+    s = &s[digits_end..];
+    if !any_digits {
+        return Err(ParseIntValueError::MissingDigits);
+    }
+    let width = if parse_type {
+        const HDL_PREFIX: &[u8] = b"hdl_";
+        let mut missing_type = ParseIntValueError::MissingType;
+        if s.as_bytes()
+            .get(..HDL_PREFIX.len())
+            .is_some_and(|bytes| bytes.eq_ignore_ascii_case(HDL_PREFIX))
+        {
+            s = &s[HDL_PREFIX.len()..];
+            missing_type = ParseIntValueError::InvalidType;
+        }
+        let signed = match s.bytes().next() {
+            Some(b'u' | b'U') => false,
+            Some(b'i' | b'I') => true,
+            Some(_) => return Err(ParseIntValueError::InvalidType),
+            None => return Err(missing_type),
+        };
+        s = &s[1..];
+        let mut width = 0usize;
+        let mut any_digits = false;
+        for ch in s.bytes() {
+            let digit = (ch as char)
+                .to_digit(10)
+                .ok_or(ParseIntValueError::InvalidDigit)?;
+            any_digits = true;
+            width = width
+                .checked_mul(10)
+                .and_then(|v| v.checked_add(digit as usize))
+                .ok_or(ParseIntValueError::WidthOverflow)?;
+        }
+        if !any_digits {
+            return Err(ParseIntValueError::MissingDigits);
+        }
+        if width > <BitSlice>::MAX_BITS {
+            return Err(ParseIntValueError::WidthOverflow);
+        }
+        let expected_width = type_width.unwrap_or(width);
+        if type_is_signed != signed || expected_width != width {
+            let expected_width = type_width.unwrap_or(width);
+            return Err(ParseIntValueError::TypeMismatch {
+                parsed_signed: signed,
+                parsed_width: width,
+                expected_signed: type_is_signed,
+                expected_width,
+            });
+        }
+        width
+    } else {
+        if !s.is_empty() {
+            return Err(ParseIntValueError::InvalidDigit);
+        }
+        type_width.expect("checked earlier")
+    };
+    if !type_is_signed && negative {
+        return Err(ParseIntValueError::InvalidDigit);
+    }
+    if radix == 10 {
+        let mut value: BigInt = digits
+            .replace("_", "")
+            .parse()
+            .expect("checked that the digits are valid already");
+        if negative {
+            value = -value;
+        }
+        let uint_value: UIntValue = UInt::new(width).from_bigint_wrapping(&value);
+        if value.is_zero() {
+            Ok(uint_value.into_bits())
+        } else {
+            for i in 0..width {
+                value.set_bit(i as u64, type_is_signed && negative);
+            }
+            if value.is_zero() {
+                Ok(uint_value.into_bits())
+            } else if type_is_signed && negative {
+                if value.sign() == Sign::Minus && value.magnitude().is_one() {
+                    Ok(uint_value.into_bits())
+                } else {
+                    Err(ParseIntValueError::NegOverflow)
+                }
+            } else {
+                Err(ParseIntValueError::PosOverflow)
+            }
+        }
+    } else {
+        let mut value = BitVec::repeat(false, width);
+        let bits_per_digit = match radix {
+            2 => 1,
+            8 => 3,
+            16 => 4,
+            _ => unreachable!(),
+        };
+        let mut digits = digits
+            .bytes()
+            .rev()
+            .filter_map(|ch| (ch as char).to_digit(radix));
+        let overflow_error = if negative {
+            ParseIntValueError::NegOverflow
+        } else {
+            ParseIntValueError::PosOverflow
+        };
+        for chunk in value.chunks_mut(bits_per_digit) {
+            if let Some(mut digit) = digits.next() {
+                let digit_bits = &mut digit.view_bits_mut::<Lsb0>()[..chunk.len()];
+                chunk.clone_from_bitslice(digit_bits);
+                digit_bits.fill(false);
+                if digit != 0 {
+                    return Err(overflow_error);
+                }
+            } else {
+                break;
+            }
+        }
+        for digit in digits {
+            if digit != 0 {
+                return Err(overflow_error);
+            }
+        }
+        let negative_zero = if negative {
+            // negating a value happens in three regions:
+            // * the least-significant zeros, which are left as zeros
+            // * the least-significant one bit, which is left as a one bit
+            // * all the most-significant bits, which are inverted
+            // e.g.:
+            const {
+                let inp = 0b1010_1_000_u8;
+                let out = 0b0101_1_000_u8;
+                assert!(inp.wrapping_neg() == out);
+            };
+            if let Some(first_one) = value.first_one() {
+                let most_significant_bits = &mut value[first_one + 1..];
+                // modifies in-place despite using `Not::not`
+                let _ = Not::not(most_significant_bits);
+                false
+            } else {
+                true
+            }
+        } else {
+            false
+        };
+        if !negative_zero && type_is_signed && negative != value[value.len() - 1] {
+            Err(overflow_error)
+        } else {
+            Ok(Arc::new(value))
+        }
+    }
+}
+
+fn deserialize_int_value<'de, D: Deserializer<'de>>(
+    deserializer: D,
+    type_is_signed: bool,
+    type_width: Option<usize>,
+) -> Result<Arc<BitVec>, D::Error> {
+    struct IntValueVisitor {
+        type_is_signed: bool,
+        type_width: Option<usize>,
+    }
+    impl<'de> Visitor<'de> for IntValueVisitor {
+        type Value = Arc<BitVec>;
+
+        fn expecting(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            f.write_str(if self.type_is_signed {
+                "SIntValue"
+            } else {
+                "UIntValue"
+            })?;
+            if let Some(type_width) = self.type_width {
+                write!(f, "<{type_width}>")?;
+            }
+            Ok(())
+        }
+
+        fn visit_str<E: Error>(self, v: &str) -> Result<Self::Value, E> {
+            parse_int_value(v, self.type_is_signed, self.type_width, true).map_err(E::custom)
+        }
+
+        fn visit_bytes<E: Error>(self, v: &[u8]) -> Result<Self::Value, E> {
+            match std::str::from_utf8(v) {
+                Ok(v) => self.visit_str(v),
+                Err(_) => Err(Error::invalid_value(serde::de::Unexpected::Bytes(v), &self)),
+            }
+        }
+    }
+    deserializer.deserialize_str(IntValueVisitor {
+        type_is_signed,
+        type_width,
+    })
+}
+
 macro_rules! impl_int {
     ($pretty_name:ident, $name:ident, $generic_name:ident, $value:ident, $SIGNED:literal) => {
         #[derive(Copy, Clone, PartialEq, Eq, Hash)]
@@ -188,19 +554,14 @@ macro_rules! impl_int {
         pub const $name: $generic_name = $generic_name;
 
         impl<Width: Size> $name<Width> {
-            pub fn new(width: Width::SizeType) -> Self {
+            pub const fn new(width: Width::SizeType) -> Self {
                 Self { width }
             }
             pub fn width(self) -> usize {
                 Width::as_usize(self.width)
             }
             pub fn type_properties(self) -> TypeProperties {
-                TypeProperties {
-                    is_passive: true,
-                    is_storable: true,
-                    is_castable_from_bits: true,
-                    bit_width: self.width(),
-                }
+                self.as_dyn_int().type_properties_dyn()
             }
             pub fn bits_from_bigint_wrapping(self, v: &BigInt) -> BitVec {
                 BoolOrIntType::bits_from_bigint_wrapping(self, v)
@@ -263,6 +624,12 @@ macro_rules! impl_int {
                 }
                 Expr::from_dyn_int(MemoizeBitsToExpr.get_cow(bits))
             }
+            fn from_str_without_ty(
+                self,
+                s: &str,
+            ) -> Result<Self::Value, <Self::Value as FromStr>::Err> {
+                parse_int_value(s, $SIGNED, Some(self.width()), false).map(Self::Value::new)
+            }
         }
 
         impl<Width: Size> IntType for $name<Width> {
@@ -270,12 +637,20 @@ macro_rules! impl_int {
         }
 
         impl $name {
-            pub fn new_dyn(width: usize) -> Self {
+            pub const fn new_dyn(width: usize) -> Self {
                 Self { width }
             }
             pub fn bits_to_bigint(bits: &BitSlice) -> BigInt {
                 <Self as BoolOrIntType>::bits_to_bigint(bits)
             }
+            pub const fn type_properties_dyn(self) -> TypeProperties {
+                TypeProperties {
+                    is_passive: true,
+                    is_storable: true,
+                    is_castable_from_bits: true,
+                    bit_width: self.width,
+                }
+            }
         }
 
         impl<Width: KnownSize> $name<Width> {
@@ -287,6 +662,7 @@ macro_rules! impl_int {
         impl<Width: Size> Type for $name<Width> {
             type BaseType = $pretty_name;
             type MaskType = Bool;
+            type SimValue = $value<Width>;
             impl_match_variant_as_self!();
             fn mask_type(&self) -> Self::MaskType {
                 Bool
@@ -297,7 +673,7 @@ macro_rules! impl_int {
             #[track_caller]
             fn from_canonical(canonical_type: CanonicalType) -> Self {
                 let CanonicalType::$pretty_name(retval) = canonical_type else {
-                    panic!("expected {}", stringify!($name));
+                    panic!("expected {}", stringify!($pretty_name));
                 };
                 $name {
                     width: Width::from_usize(retval.width),
@@ -306,20 +682,78 @@ macro_rules! impl_int {
             fn source_location() -> SourceLocation {
                 SourceLocation::builtin()
             }
+            fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+                assert_eq!(bits.len(), self.width());
+                $value::new(Arc::new(bits.to_bitvec()))
+            }
+            fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+                assert_eq!(bits.len(), self.width());
+                assert_eq!(value.width(), self.width());
+                value.bits_mut().copy_from_bitslice(bits);
+            }
+            fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+                assert_eq!(bits.len(), self.width());
+                assert_eq!(value.width(), self.width());
+                bits.copy_from_bitslice(value.bits());
+            }
+        }
+
+        impl<Width: KnownSize> Default for $name<Width> {
+            fn default() -> Self {
+                Self::TYPE
+            }
         }
 
         impl<Width: KnownSize> StaticType for $name<Width> {
             const TYPE: Self = Self { width: Width::SIZE };
             const MASK_TYPE: Self::MaskType = Bool;
-            const TYPE_PROPERTIES: TypeProperties = TypeProperties {
-                is_passive: true,
-                is_storable: true,
-                is_castable_from_bits: true,
-                bit_width: Width::VALUE,
-            };
+            const TYPE_PROPERTIES: TypeProperties = $name {
+                width: Width::VALUE,
+            }
+            .type_properties_dyn();
             const MASK_TYPE_PROPERTIES: TypeProperties = Bool::TYPE_PROPERTIES;
         }
 
+        impl<Width: Size> Serialize for $name<Width> {
+            fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+            where
+                S: Serializer,
+            {
+                self.canonical().serialize(serializer)
+            }
+        }
+
+        impl<'de, Width: Size> Deserialize<'de> for $name<Width> {
+            fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+            where
+                D: Deserializer<'de>,
+            {
+                let name = |width| -> String {
+                    if let Some(width) = width {
+                        format!("a {}<{width}>", stringify!($pretty_name))
+                    } else {
+                        format!("a {}", stringify!($pretty_name))
+                    }
+                };
+                match CanonicalType::deserialize(deserializer)? {
+                    CanonicalType::$pretty_name(retval) => {
+                        if let Some(width) = Width::try_from_usize(retval.width()) {
+                            Ok($name { width })
+                        } else {
+                            Err(Error::invalid_value(
+                                serde::de::Unexpected::Other(&name(Some(retval.width()))),
+                                &&*name(Width::KNOWN_VALUE),
+                            ))
+                        }
+                    }
+                    ty => Err(Error::invalid_value(
+                        serde::de::Unexpected::Other(ty.as_serde_unexpected_str()),
+                        &&*name(Width::KNOWN_VALUE),
+                    )),
+                }
+            }
+        }
+
         #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Default)]
         pub struct $generic_name;
 
@@ -337,7 +771,7 @@ macro_rules! impl_int {
             _phantom: PhantomData<Width>,
         }
 
-        impl<Width: Size> fmt::Debug for $value<Width> {
+        impl<Width: Size> fmt::Display for $value<Width> {
             fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                 let value = self.to_bigint();
                 let (sign, magnitude) = value.into_parts();
@@ -351,15 +785,38 @@ macro_rules! impl_int {
             }
         }
 
-        impl<Width: Size> PartialOrd for $value<Width> {
-            fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-                Some(self.cmp(other))
+        impl<Width: Size> fmt::Debug for $value<Width> {
+            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+                fmt::Display::fmt(self, f)
             }
         }
 
-        impl<Width: Size> Ord for $value<Width> {
-            fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-                self.to_bigint().cmp(&other.to_bigint())
+        impl<Width: Size> std::str::FromStr for $value<Width> {
+            type Err = ParseIntValueError;
+
+            fn from_str(s: &str) -> Result<Self, Self::Err> {
+                parse_int_value(s, $SIGNED, Width::KNOWN_VALUE, true).map(Self::new)
+            }
+        }
+
+        impl<Width: Size> Serialize for $value<Width> {
+            fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+                self.to_string().serialize(serializer)
+            }
+        }
+
+        impl<'de, Width: Size> Deserialize<'de> for $value<Width> {
+            fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+                deserialize_int_value(deserializer, $SIGNED, Width::KNOWN_VALUE).map(Self::new)
+            }
+        }
+
+        impl<Width: Size> PartialOrd for $value<Width> {
+            fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+                if self.width() != other.width() {
+                    return None;
+                }
+                Some(self.to_bigint().cmp(&other.to_bigint()))
             }
         }
 
@@ -401,6 +858,9 @@ macro_rules! impl_int {
             pub fn bits(&self) -> &Arc<BitVec> {
                 &self.bits
             }
+            pub fn bits_mut(&mut self) -> &mut BitSlice {
+                Arc::<BitVec>::make_mut(&mut self.bits)
+            }
         }
 
         impl<Width: Size> ToLiteralBits for $value<Width> {
@@ -455,6 +915,10 @@ impl UInt {
         let v: BigUint = v.into();
         Self::new(v.bits().try_into().expect("too big"))
     }
+    /// gets the smallest `UInt` that fits `v` losslessly
+    pub const fn for_value_usize(v: usize) -> Self {
+        Self::new((usize::BITS - v.leading_zeros()) as usize)
+    }
     /// gets the smallest `UInt` that fits `r` losslessly, panics if `r` is empty
     #[track_caller]
     pub fn range(r: Range<impl Into<BigUint>>) -> Self {
@@ -465,6 +929,12 @@ impl UInt {
     }
     /// gets the smallest `UInt` that fits `r` losslessly, panics if `r` is empty
     #[track_caller]
+    pub const fn range_usize(r: Range<usize>) -> Self {
+        assert!(r.end != 0, "empty range");
+        Self::range_inclusive_usize(r.start..=(r.end - 1))
+    }
+    /// gets the smallest `UInt` that fits `r` losslessly, panics if `r` is empty
+    #[track_caller]
     pub fn range_inclusive(r: RangeInclusive<impl Into<BigUint>>) -> Self {
         let (start, end) = r.into_inner();
         let start: BigUint = start.into();
@@ -474,6 +944,16 @@ impl UInt {
         // so must not take more bits than `end`
         Self::for_value(end)
     }
+    /// gets the smallest `UInt` that fits `r` losslessly, panics if `r` is empty
+    #[track_caller]
+    pub const fn range_inclusive_usize(r: RangeInclusive<usize>) -> Self {
+        let start = *r.start();
+        let end = *r.end();
+        assert!(start <= end, "empty range");
+        // no need to check `start`` since it's no larger than `end`
+        // so must not take more bits than `end`
+        Self::for_value_usize(end)
+    }
 }
 
 impl SInt {
@@ -580,14 +1060,17 @@ pub trait BoolOrIntType: Type + sealed::BoolOrIntTypeSealed {
     type Width: Size;
     type Signed: GenericConstBool;
     type Value: Clone
-        + Ord
+        + PartialOrd
+        + Eq
         + std::hash::Hash
         + fmt::Debug
+        + fmt::Display
         + Send
         + Sync
         + 'static
         + ToExpr<Type = Self>
-        + Into<BigInt>;
+        + Into<BigInt>
+        + std::str::FromStr;
     fn width(self) -> usize;
     fn new(width: <Self::Width as Size>::SizeType) -> Self;
     fn new_static() -> Self
@@ -621,6 +1104,12 @@ pub trait BoolOrIntType: Type + sealed::BoolOrIntTypeSealed {
         let bitslice = &BitSlice::<u8, Lsb0>::from_slice(&bytes)[..width];
         bits.clone_from_bitslice(bitslice);
     }
+    fn bits_equal_bigint_wrapping(v: &BigInt, bits: &BitSlice) -> bool {
+        bits.iter()
+            .by_vals()
+            .enumerate()
+            .all(|(bit_index, bit): (usize, bool)| v.bit(bit_index as u64) == bit)
+    }
     fn bits_to_bigint(bits: &BitSlice) -> BigInt {
         let sign_byte = if Self::Signed::VALUE && bits.last().as_deref().copied().unwrap_or(false) {
             0xFF
@@ -654,9 +1143,12 @@ pub trait BoolOrIntType: Type + sealed::BoolOrIntTypeSealed {
             bytes, bit_width,
         )))
     }
+    fn from_str_without_ty(self, s: &str) -> Result<Self::Value, <Self::Value as FromStr>::Err>;
 }
 
-pub trait IntType: BoolOrIntType<BaseType = <Self as IntType>::Dyn> {
+pub trait IntType:
+    BoolOrIntType<BaseType = <Self as IntType>::Dyn, Value: FromStr<Err = ParseIntValueError>>
+{
     type Dyn: IntType<Dyn = Self::Dyn, Signed = Self::Signed, Width = DynSize>;
     fn as_dyn_int(self) -> Self::Dyn {
         Self::new_dyn(self.width())
@@ -696,7 +1188,7 @@ pub trait IntType: BoolOrIntType<BaseType = <Self as IntType>::Dyn> {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Default)]
 pub struct Bool;
 
 impl sealed::BoolOrIntTypeSealed for Bool {}
@@ -728,6 +1220,10 @@ impl BoolOrIntType for Bool {
         assert_eq!(bits.len(), 1);
         bits[0]
     }
+
+    fn from_str_without_ty(self, s: &str) -> Result<Self::Value, <Self::Value as FromStr>::Err> {
+        FromStr::from_str(s)
+    }
 }
 
 impl Bool {
@@ -742,6 +1238,7 @@ impl Bool {
 impl Type for Bool {
     type BaseType = Bool;
     type MaskType = Bool;
+    type SimValue = bool;
     impl_match_variant_as_self!();
     fn mask_type(&self) -> Self::MaskType {
         Bool
@@ -759,6 +1256,18 @@ impl Type for Bool {
     fn source_location() -> SourceLocation {
         SourceLocation::builtin()
     }
+    fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+        assert_eq!(bits.len(), 1);
+        bits[0]
+    }
+    fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+        assert_eq!(bits.len(), 1);
+        *value = bits[0];
+    }
+    fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+        assert_eq!(bits.len(), 1);
+        bits.set(0, *value);
+    }
 }
 
 impl StaticType for Bool {
@@ -783,6 +1292,13 @@ impl ToLiteralBits for bool {
 mod tests {
     use super::*;
 
+    #[test]
+    fn test_different_value_widths_compare_ne() {
+        // interning relies on [SU]IntValue with different `width` comparing not equal
+        assert_ne!(UInt[3].from_int_wrapping(0), UInt[4].from_int_wrapping(0));
+        assert_ne!(SInt[3].from_int_wrapping(0), SInt[4].from_int_wrapping(0));
+    }
+
     #[test]
     fn test_uint_for_value() {
         assert_eq!(UInt::for_value(0u8).width, 0);
@@ -805,4 +1321,104 @@ mod tests {
         assert_eq!(SInt::for_value(3).width, 3);
         assert_eq!(SInt::for_value(4).width, 4);
     }
+
+    #[test]
+    fn test_serde_round_trip() {
+        use serde_json::json;
+        #[track_caller]
+        fn check<T: Serialize + DeserializeOwned + PartialEq + fmt::Debug>(
+            value: T,
+            expected: serde_json::Value,
+        ) {
+            assert_eq!(serde_json::to_value(&value).unwrap(), expected);
+            assert_eq!(value, T::deserialize(expected).unwrap());
+        }
+        check(UInt[0], json! { { "UInt": { "width": 0 } } });
+        check(UInt::<0>::TYPE, json! { { "UInt": { "width": 0 } } });
+        check(UInt::<35>::TYPE, json! { { "UInt": { "width": 35 } } });
+        check(SInt[0], json! { { "SInt": { "width": 0 } } });
+        check(SInt::<0>::TYPE, json! { { "SInt": { "width": 0 } } });
+        check(SInt::<35>::TYPE, json! { { "SInt": { "width": 35 } } });
+        check(Bool, json! { "Bool" });
+        check(UIntValue::from(0u8), json! { "0x0_u8" });
+        check(SIntValue::from(-128i8), json! { "-0x80_i8" });
+        check(UInt[3].from_int_wrapping(5), json! { "0x5_u3" });
+        check(UInt[12].from_int_wrapping(0x1123), json! { "0x123_u12" });
+        check(SInt[12].from_int_wrapping(0xFEE), json! { "-0x12_i12" });
+        check(SInt[12].from_int_wrapping(0x7EE), json! { "0x7EE_i12" });
+    }
+
+    #[test]
+    fn test_deserialize() {
+        use serde_json::json;
+        #[track_caller]
+        fn check<T: DeserializeOwned + fmt::Debug + PartialEq>(
+            expected: Result<T, &str>,
+            input: serde_json::Value,
+        ) {
+            let mut error = String::new();
+            let value = T::deserialize(input).map_err(|e| -> &str {
+                error = e.to_string();
+                &error
+            });
+            assert_eq!(value, expected);
+        }
+        check::<UInt<0>>(
+            Err("invalid value: a UInt<2>, expected a UInt<0>"),
+            json! { { "UInt": { "width": 2 } } },
+        );
+        check::<UInt<0>>(
+            Err("invalid value: a Bool, expected a UInt<0>"),
+            json! { "Bool" },
+        );
+        check::<SInt<0>>(
+            Err("invalid value: a Bool, expected a SInt<0>"),
+            json! { "Bool" },
+        );
+        check::<UInt>(
+            Err("invalid value: a Bool, expected a UInt"),
+            json! { "Bool" },
+        );
+        check::<SInt>(
+            Err("invalid value: a Bool, expected a SInt"),
+            json! { "Bool" },
+        );
+        check::<UIntValue>(Err("value too large to fit in type"), json! { "2_u1" });
+        check::<UIntValue>(Err("value too large to fit in type"), json! { "10_u1" });
+        check::<UIntValue>(Err("value too large to fit in type"), json! { "0x2_u1" });
+        check::<UIntValue>(Err("value too large to fit in type"), json! { "0b10_u1" });
+        check::<UIntValue>(Err("value too large to fit in type"), json! { "0o2_u1" });
+        check::<SIntValue>(Err("value too large to fit in type"), json! { "0o377_i8" });
+        check::<SIntValue>(Err("value too large to fit in type"), json! { "0o200_i8" });
+        check(Ok(SInt[8].from_int_wrapping(i8::MAX)), json! { "0o177_i8" });
+        check::<SIntValue>(Err("value too small to fit in type"), json! { "-0o201_i8" });
+        check::<SIntValue>(Err("value too small to fit in type"), json! { "-0o377_i8" });
+        check::<SIntValue>(Err("value too small to fit in type"), json! { "-0o400_i8" });
+        check::<SIntValue>(
+            Err("value too small to fit in type"),
+            json! { "-0o4000_i8" },
+        );
+        check(Ok(UIntValue::from(0u8)), json! { "0_u8" });
+        check(Ok(UIntValue::from(0u8)), json! { "0b0_u8" });
+        check(Ok(UIntValue::from(0u8)), json! { "00_u8" });
+        check(Ok(UIntValue::from(0u8)), json! { "0x0_u8" });
+        check(Ok(UIntValue::from(0u8)), json! { "0o0_u8" });
+        check(Ok(SIntValue::from(-128i8)), json! { "-0x000_80_i8" });
+        check(Ok(SIntValue::from(-128i8)), json! { "-0o002_00_hdl_i8" });
+        check(Ok(SIntValue::from(-128i8)), json! { "-0b1__000_0000_i8" });
+        check(Ok(UInt[3].from_int_wrapping(5)), json! { " + 0x5_u3 " });
+        check(
+            Ok(UInt[12].from_int_wrapping(0x1123)),
+            json! { "0x1_2_3_hdl_u12" },
+        );
+        check(Ok(SInt[12].from_int_wrapping(0xFEE)), json! { "-0x12_i12" });
+        check(
+            Ok(SInt[12].from_int_wrapping(0x7EE)),
+            json! { " + \t0x7__E_e_i012\n" },
+        );
+        check(Ok(SInt[0].from_int_wrapping(0)), json! { "-0i0" });
+        check(Ok(SInt[1].from_int_wrapping(0)), json! { "-0i1" });
+        check(Ok(SInt[0].from_int_wrapping(0)), json! { "-0x0i0" });
+        check(Ok(SInt[1].from_int_wrapping(0)), json! { "-0x0i1" });
+    }
 }

crates/fayalite/src/int/uint_in_range.rs

@@ -0,0 +1,614 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+use crate::{
+    bundle::{Bundle, BundleField, BundleType, BundleTypePropertiesBuilder, NoBuilder},
+    expr::{
+        ops::{ExprCastTo, ExprPartialEq, ExprPartialOrd},
+        CastBitsTo, CastTo, CastToBits, Expr, HdlPartialEq, HdlPartialOrd,
+    },
+    int::{Bool, DynSize, KnownSize, Size, SizeType, UInt, UIntType},
+    intern::{Intern, Interned},
+    phantom_const::PhantomConst,
+    sim::value::{SimValue, SimValuePartialEq, ToSimValueWithType},
+    source_location::SourceLocation,
+    ty::{impl_match_variant_as_self, CanonicalType, StaticType, Type, TypeProperties},
+};
+use bitvec::{order::Lsb0, slice::BitSlice, view::BitView};
+use serde::{
+    de::{value::UsizeDeserializer, Error, Visitor},
+    Deserialize, Deserializer, Serialize, Serializer,
+};
+use std::{fmt, marker::PhantomData, ops::Index};
+
+const UINT_IN_RANGE_TYPE_FIELD_NAMES: [&'static str; 2] = ["value", "range"];
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Default)]
+pub struct UIntInRangeMaskType {
+    value: Bool,
+    range: PhantomConstRangeMaskType,
+}
+
+impl Type for UIntInRangeMaskType {
+    type BaseType = Bundle;
+    type MaskType = Self;
+    type SimValue = bool;
+    impl_match_variant_as_self!();
+
+    fn mask_type(&self) -> Self::MaskType {
+        *self
+    }
+
+    fn canonical(&self) -> CanonicalType {
+        CanonicalType::Bundle(Bundle::new(self.fields()))
+    }
+
+    fn from_canonical(canonical_type: CanonicalType) -> Self {
+        let fields = Bundle::from_canonical(canonical_type).fields();
+        let [BundleField {
+            name: value_name,
+            flipped: false,
+            ty: value,
+        }, BundleField {
+            name: range_name,
+            flipped: false,
+            ty: range,
+        }] = *fields
+        else {
+            panic!("expected UIntInRangeMaskType");
+        };
+        assert_eq!([&*value_name, &*range_name], UINT_IN_RANGE_TYPE_FIELD_NAMES);
+        let value = Bool::from_canonical(value);
+        let range = PhantomConstRangeMaskType::from_canonical(range);
+        Self { value, range }
+    }
+
+    fn source_location() -> SourceLocation {
+        SourceLocation::builtin()
+    }
+
+    fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+        Bool.sim_value_from_bits(bits)
+    }
+
+    fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+        Bool.sim_value_clone_from_bits(value, bits);
+    }
+
+    fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+        Bool.sim_value_to_bits(value, bits);
+    }
+}
+
+impl BundleType for UIntInRangeMaskType {
+    type Builder = NoBuilder;
+    type FilledBuilder = Expr<UIntInRangeMaskType>;
+
+    fn fields(&self) -> Interned<[BundleField]> {
+        let [value_name, range_name] = UINT_IN_RANGE_TYPE_FIELD_NAMES;
+        let Self { value, range } = self;
+        [
+            BundleField {
+                name: value_name.intern(),
+                flipped: false,
+                ty: value.canonical(),
+            },
+            BundleField {
+                name: range_name.intern(),
+                flipped: false,
+                ty: range.canonical(),
+            },
+        ][..]
+            .intern()
+    }
+}
+
+impl StaticType for UIntInRangeMaskType {
+    const TYPE: Self = Self {
+        value: Bool,
+        range: PhantomConstRangeMaskType::TYPE,
+    };
+    const MASK_TYPE: Self::MaskType = Self::TYPE;
+    const TYPE_PROPERTIES: TypeProperties = BundleTypePropertiesBuilder::new()
+        .field(false, Bool::TYPE_PROPERTIES)
+        .field(false, PhantomConstRangeMaskType::TYPE_PROPERTIES)
+        .finish();
+    const MASK_TYPE_PROPERTIES: TypeProperties = Self::TYPE_PROPERTIES;
+}
+
+impl ToSimValueWithType<UIntInRangeMaskType> for bool {
+    fn to_sim_value_with_type(&self, ty: UIntInRangeMaskType) -> SimValue<UIntInRangeMaskType> {
+        SimValue::from_value(ty, *self)
+    }
+}
+
+impl ExprCastTo<Bool> for UIntInRangeMaskType {
+    fn cast_to(src: Expr<Self>, to_type: Bool) -> Expr<Bool> {
+        src.cast_to_bits().cast_to(to_type)
+    }
+}
+
+impl ExprCastTo<UIntInRangeMaskType> for Bool {
+    fn cast_to(src: Expr<Self>, to_type: UIntInRangeMaskType) -> Expr<UIntInRangeMaskType> {
+        src.cast_to_static::<UInt<1>>().cast_bits_to(to_type)
+    }
+}
+
+impl ExprPartialEq<Self> for UIntInRangeMaskType {
+    fn cmp_eq(lhs: Expr<Self>, rhs: Expr<Self>) -> Expr<Bool> {
+        lhs.cast_to_bits().cmp_eq(rhs.cast_to_bits())
+    }
+    fn cmp_ne(lhs: Expr<Self>, rhs: Expr<Self>) -> Expr<Bool> {
+        lhs.cast_to_bits().cmp_ne(rhs.cast_to_bits())
+    }
+}
+
+impl SimValuePartialEq<Self> for UIntInRangeMaskType {
+    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<Self>) -> bool {
+        **this == **other
+    }
+}
+
+type PhantomConstRangeMaskType = <PhantomConst<SerdeRange<DynSize, DynSize>> as Type>::MaskType;
+
+#[derive(Default, Copy, Clone, Debug)]
+struct RangeParseError;
+
+macro_rules! define_uint_in_range_type {
+    (
+        $UIntInRange:ident,
+        $UIntInRangeType:ident,
+        $UIntInRangeTypeWithoutGenerics:ident,
+        $UIntInRangeTypeWithStart:ident,
+        $SerdeRange:ident,
+        $range_operator_str:literal,
+        |$uint_range_usize_start:ident, $uint_range_usize_end:ident| $uint_range_usize:expr,
+    ) => {
+        #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+        struct $SerdeRange<Start: Size, End: Size> {
+            start: Start::SizeType,
+            end: End::SizeType,
+        }
+
+        impl<Start: KnownSize, End: KnownSize> Default for $SerdeRange<Start, End> {
+            fn default() -> Self {
+                Self {
+                    start: Start::SIZE,
+                    end: End::SIZE,
+                }
+            }
+        }
+
+        impl std::str::FromStr for $SerdeRange<DynSize, DynSize> {
+            type Err = RangeParseError;
+
+            fn from_str(s: &str) -> Result<Self, Self::Err> {
+                let Some((start, end)) = s.split_once($range_operator_str) else {
+                    return Err(RangeParseError);
+                };
+                if start.is_empty()
+                    || start.bytes().any(|b| !b.is_ascii_digit())
+                    || end.is_empty()
+                    || end.bytes().any(|b| !b.is_ascii_digit())
+                {
+                    return Err(RangeParseError);
+                }
+                let start = start.parse().map_err(|_| RangeParseError)?;
+                let end = end.parse().map_err(|_| RangeParseError)?;
+                let retval = Self { start, end };
+                if retval.is_empty() {
+                    Err(RangeParseError)
+                } else {
+                    Ok(retval)
+                }
+            }
+        }
+
+        impl<Start: Size, End: Size> fmt::Display for $SerdeRange<Start, End> {
+            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+                let Self { start, end } = *self;
+                write!(
+                    f,
+                    "{}{}{}",
+                    Start::as_usize(start),
+                    $range_operator_str,
+                    End::as_usize(end),
+                )
+            }
+        }
+
+        impl<Start: Size, End: Size> Serialize for $SerdeRange<Start, End> {
+            fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+                serializer.collect_str(self)
+            }
+        }
+
+        impl<'de, Start: Size, End: Size> Deserialize<'de> for $SerdeRange<Start, End> {
+            fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+                struct SerdeRangeVisitor<Start: Size, End: Size>(PhantomData<(Start, End)>);
+                impl<'de, Start: Size, End: Size> Visitor<'de> for SerdeRangeVisitor<Start, End> {
+                    type Value = $SerdeRange<Start, End>;
+
+                    fn expecting(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+                        f.write_str("a string with format \"")?;
+                        if let Some(start) = Start::KNOWN_VALUE {
+                            write!(f, "{start}")?;
+                        } else {
+                            f.write_str("<int>")?;
+                        };
+                        f.write_str($range_operator_str)?;
+                        if let Some(end) = End::KNOWN_VALUE {
+                            write!(f, "{end}")?;
+                        } else {
+                            f.write_str("<int>")?;
+                        };
+                        f.write_str("\" that is a non-empty range")
+                    }
+
+                    fn visit_str<E: Error>(self, v: &str) -> Result<Self::Value, E> {
+                        let $SerdeRange::<DynSize, DynSize> { start, end } =
+                            v.parse().map_err(|_| {
+                                Error::invalid_value(serde::de::Unexpected::Str(v), &self)
+                            })?;
+                        let start =
+                            Start::SizeType::deserialize(UsizeDeserializer::<E>::new(start))?;
+                        let end = End::SizeType::deserialize(UsizeDeserializer::<E>::new(end))?;
+                        Ok($SerdeRange { start, end })
+                    }
+
+                    fn visit_bytes<E: Error>(self, v: &[u8]) -> Result<Self::Value, E> {
+                        match std::str::from_utf8(v) {
+                            Ok(v) => self.visit_str(v),
+                            Err(_) => {
+                                Err(Error::invalid_value(serde::de::Unexpected::Bytes(v), &self))
+                            }
+                        }
+                    }
+                }
+                deserializer.deserialize_str(SerdeRangeVisitor(PhantomData))
+            }
+        }
+
+        #[derive(Copy, Clone, PartialEq, Eq, Hash)]
+        pub struct $UIntInRangeType<Start: Size, End: Size> {
+            value: UInt,
+            range: PhantomConst<$SerdeRange<Start, End>>,
+        }
+
+        impl<Start: Size, End: Size> $UIntInRangeType<Start, End> {
+            fn from_phantom_const_range(range: PhantomConst<$SerdeRange<Start, End>>) -> Self {
+                let $SerdeRange { start, end } = *range.get();
+                let $uint_range_usize_start = Start::as_usize(start);
+                let $uint_range_usize_end = End::as_usize(end);
+                Self {
+                    value: $uint_range_usize,
+                    range,
+                }
+            }
+            pub fn new(start: Start::SizeType, end: End::SizeType) -> Self {
+                Self::from_phantom_const_range(PhantomConst::new(
+                    $SerdeRange { start, end }.intern_sized(),
+                ))
+            }
+        }
+
+        impl<Start: Size, End: Size> fmt::Debug for $UIntInRangeType<Start, End> {
+            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+                let Self { value, range } = self;
+                let $SerdeRange { start, end } = *range.get();
+                f.debug_struct(&format!(
+                    "{}<{}, {}>",
+                    stringify!($UIntInRange),
+                    Start::as_usize(start),
+                    End::as_usize(end),
+                ))
+                .field("value", value)
+                .finish_non_exhaustive()
+            }
+        }
+
+        impl<Start: Size, End: Size> Type for $UIntInRangeType<Start, End> {
+            type BaseType = Bundle;
+            type MaskType = UIntInRangeMaskType;
+            type SimValue = usize;
+            impl_match_variant_as_self!();
+
+            fn mask_type(&self) -> Self::MaskType {
+                UIntInRangeMaskType::TYPE
+            }
+
+            fn canonical(&self) -> CanonicalType {
+                CanonicalType::Bundle(Bundle::new(self.fields()))
+            }
+
+            fn from_canonical(canonical_type: CanonicalType) -> Self {
+                let fields = Bundle::from_canonical(canonical_type).fields();
+                let [BundleField {
+                    name: value_name,
+                    flipped: false,
+                    ty: value,
+                }, BundleField {
+                    name: range_name,
+                    flipped: false,
+                    ty: range,
+                }] = *fields
+                else {
+                    panic!("expected {}", stringify!($UIntInRange));
+                };
+                assert_eq!([&*value_name, &*range_name], UINT_IN_RANGE_TYPE_FIELD_NAMES);
+                let value = UInt::from_canonical(value);
+                let range = PhantomConst::<$SerdeRange<Start, End>>::from_canonical(range);
+                let retval = Self::from_phantom_const_range(range);
+                assert_eq!(retval, Self { value, range });
+                retval
+            }
+
+            fn source_location() -> SourceLocation {
+                SourceLocation::builtin()
+            }
+
+            fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+                let mut retval = 0usize;
+                retval.view_bits_mut::<Lsb0>()[..bits.len()].clone_from_bitslice(bits);
+                retval
+            }
+
+            fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+                *value = self.sim_value_from_bits(bits);
+            }
+
+            fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+                bits.clone_from_bitslice(&value.view_bits::<Lsb0>()[..bits.len()]);
+            }
+        }
+
+        impl<Start: Size, End: Size> BundleType for $UIntInRangeType<Start, End> {
+            type Builder = NoBuilder;
+            type FilledBuilder = Expr<Self>;
+
+            fn fields(&self) -> Interned<[BundleField]> {
+                let [value_name, range_name] = UINT_IN_RANGE_TYPE_FIELD_NAMES;
+                let Self { value, range } = self;
+                [
+                    BundleField {
+                        name: value_name.intern(),
+                        flipped: false,
+                        ty: value.canonical(),
+                    },
+                    BundleField {
+                        name: range_name.intern(),
+                        flipped: false,
+                        ty: range.canonical(),
+                    },
+                ][..]
+                    .intern()
+            }
+        }
+
+        impl<Start: KnownSize, End: KnownSize> Default for $UIntInRangeType<Start, End> {
+            fn default() -> Self {
+                Self::TYPE
+            }
+        }
+
+        impl<Start: KnownSize, End: KnownSize> StaticType for $UIntInRangeType<Start, End> {
+            const TYPE: Self = {
+                let $uint_range_usize_start = Start::VALUE;
+                let $uint_range_usize_end = End::VALUE;
+                Self {
+                    value: $uint_range_usize,
+                    range: PhantomConst::<$SerdeRange<Start, End>>::TYPE,
+                }
+            };
+            const MASK_TYPE: Self::MaskType = UIntInRangeMaskType::TYPE;
+            const TYPE_PROPERTIES: TypeProperties = BundleTypePropertiesBuilder::new()
+                .field(false, Self::TYPE.value.type_properties_dyn())
+                .field(
+                    false,
+                    PhantomConst::<$SerdeRange<Start, End>>::TYPE_PROPERTIES,
+                )
+                .finish();
+            const MASK_TYPE_PROPERTIES: TypeProperties = UIntInRangeMaskType::TYPE_PROPERTIES;
+        }
+
+        impl<Start: Size, End: Size> ToSimValueWithType<$UIntInRangeType<Start, End>> for usize {
+            fn to_sim_value_with_type(
+                &self,
+                ty: $UIntInRangeType<Start, End>,
+            ) -> SimValue<$UIntInRangeType<Start, End>> {
+                SimValue::from_value(ty, *self)
+            }
+        }
+
+        #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Default)]
+        pub struct $UIntInRangeTypeWithoutGenerics;
+
+        #[allow(non_upper_case_globals)]
+        pub const $UIntInRangeType: $UIntInRangeTypeWithoutGenerics =
+            $UIntInRangeTypeWithoutGenerics;
+
+        impl<StartSize: SizeType> Index<StartSize> for $UIntInRangeTypeWithoutGenerics {
+            type Output = $UIntInRangeTypeWithStart<StartSize::Size>;
+
+            fn index(&self, start: StartSize) -> &Self::Output {
+                Interned::into_inner($UIntInRangeTypeWithStart(start).intern_sized())
+            }
+        }
+
+        #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+        pub struct $UIntInRangeTypeWithStart<Start: Size>(Start::SizeType);
+
+        impl<Start: Size, EndSize: SizeType<Size = End>, End: Size<SizeType = EndSize>>
+            Index<EndSize> for $UIntInRangeTypeWithStart<Start>
+        {
+            type Output = $UIntInRangeType<Start, End>;
+
+            fn index(&self, end: EndSize) -> &Self::Output {
+                Interned::into_inner($UIntInRangeType::new(self.0, end).intern_sized())
+            }
+        }
+
+        impl<Start: Size, End: Size> ExprCastTo<UInt> for $UIntInRangeType<Start, End> {
+            fn cast_to(src: Expr<Self>, to_type: UInt) -> Expr<UInt> {
+                src.cast_to_bits().cast_to(to_type)
+            }
+        }
+
+        impl<Start: Size, End: Size> ExprCastTo<$UIntInRangeType<Start, End>> for UInt {
+            fn cast_to(
+                src: Expr<Self>,
+                to_type: $UIntInRangeType<Start, End>,
+            ) -> Expr<$UIntInRangeType<Start, End>> {
+                src.cast_bits_to(to_type)
+            }
+        }
+
+        impl<LhsStart: Size, LhsEnd: Size, RhsStart: Size, RhsEnd: Size>
+            ExprPartialEq<$UIntInRangeType<RhsStart, RhsEnd>>
+            for $UIntInRangeType<LhsStart, LhsEnd>
+        {
+            fn cmp_eq(
+                lhs: Expr<Self>,
+                rhs: Expr<$UIntInRangeType<RhsStart, RhsEnd>>,
+            ) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_eq(rhs.cast_to_bits())
+            }
+            fn cmp_ne(
+                lhs: Expr<Self>,
+                rhs: Expr<$UIntInRangeType<RhsStart, RhsEnd>>,
+            ) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_ne(rhs.cast_to_bits())
+            }
+        }
+
+        impl<LhsStart: Size, LhsEnd: Size, RhsStart: Size, RhsEnd: Size>
+            ExprPartialOrd<$UIntInRangeType<RhsStart, RhsEnd>>
+            for $UIntInRangeType<LhsStart, LhsEnd>
+        {
+            fn cmp_lt(
+                lhs: Expr<Self>,
+                rhs: Expr<$UIntInRangeType<RhsStart, RhsEnd>>,
+            ) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_lt(rhs.cast_to_bits())
+            }
+            fn cmp_le(
+                lhs: Expr<Self>,
+                rhs: Expr<$UIntInRangeType<RhsStart, RhsEnd>>,
+            ) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_le(rhs.cast_to_bits())
+            }
+            fn cmp_gt(
+                lhs: Expr<Self>,
+                rhs: Expr<$UIntInRangeType<RhsStart, RhsEnd>>,
+            ) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_gt(rhs.cast_to_bits())
+            }
+            fn cmp_ge(
+                lhs: Expr<Self>,
+                rhs: Expr<$UIntInRangeType<RhsStart, RhsEnd>>,
+            ) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_ge(rhs.cast_to_bits())
+            }
+        }
+
+        impl<LhsStart: Size, LhsEnd: Size, RhsStart: Size, RhsEnd: Size>
+            SimValuePartialEq<$UIntInRangeType<RhsStart, RhsEnd>>
+            for $UIntInRangeType<LhsStart, LhsEnd>
+        {
+            fn sim_value_eq(
+                this: &SimValue<Self>,
+                other: &SimValue<$UIntInRangeType<RhsStart, RhsEnd>>,
+            ) -> bool {
+                **this == **other
+            }
+        }
+
+        impl<Start: Size, End: Size, Width: Size> ExprPartialEq<UIntType<Width>>
+            for $UIntInRangeType<Start, End>
+        {
+            fn cmp_eq(lhs: Expr<Self>, rhs: Expr<UIntType<Width>>) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_eq(rhs)
+            }
+            fn cmp_ne(lhs: Expr<Self>, rhs: Expr<UIntType<Width>>) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_ne(rhs)
+            }
+        }
+
+        impl<Start: Size, End: Size, Width: Size> ExprPartialEq<$UIntInRangeType<Start, End>>
+            for UIntType<Width>
+        {
+            fn cmp_eq(lhs: Expr<Self>, rhs: Expr<$UIntInRangeType<Start, End>>) -> Expr<Bool> {
+                lhs.cmp_eq(rhs.cast_to_bits())
+            }
+            fn cmp_ne(lhs: Expr<Self>, rhs: Expr<$UIntInRangeType<Start, End>>) -> Expr<Bool> {
+                lhs.cmp_ne(rhs.cast_to_bits())
+            }
+        }
+
+        impl<Start: Size, End: Size, Width: Size> ExprPartialOrd<UIntType<Width>>
+            for $UIntInRangeType<Start, End>
+        {
+            fn cmp_lt(lhs: Expr<Self>, rhs: Expr<UIntType<Width>>) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_lt(rhs)
+            }
+            fn cmp_le(lhs: Expr<Self>, rhs: Expr<UIntType<Width>>) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_le(rhs)
+            }
+            fn cmp_gt(lhs: Expr<Self>, rhs: Expr<UIntType<Width>>) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_gt(rhs)
+            }
+            fn cmp_ge(lhs: Expr<Self>, rhs: Expr<UIntType<Width>>) -> Expr<Bool> {
+                lhs.cast_to_bits().cmp_ge(rhs)
+            }
+        }
+
+        impl<Start: Size, End: Size, Width: Size> ExprPartialOrd<$UIntInRangeType<Start, End>>
+            for UIntType<Width>
+        {
+            fn cmp_lt(lhs: Expr<Self>, rhs: Expr<$UIntInRangeType<Start, End>>) -> Expr<Bool> {
+                lhs.cmp_lt(rhs.cast_to_bits())
+            }
+            fn cmp_le(lhs: Expr<Self>, rhs: Expr<$UIntInRangeType<Start, End>>) -> Expr<Bool> {
+                lhs.cmp_le(rhs.cast_to_bits())
+            }
+            fn cmp_gt(lhs: Expr<Self>, rhs: Expr<$UIntInRangeType<Start, End>>) -> Expr<Bool> {
+                lhs.cmp_gt(rhs.cast_to_bits())
+            }
+            fn cmp_ge(lhs: Expr<Self>, rhs: Expr<$UIntInRangeType<Start, End>>) -> Expr<Bool> {
+                lhs.cmp_ge(rhs.cast_to_bits())
+            }
+        }
+    };
+}
+
+define_uint_in_range_type! {
+    UIntInRange,
+    UIntInRangeType,
+    UIntInRangeTypeWithoutGenerics,
+    UIntInRangeTypeWithStart,
+    SerdeRange,
+    "..",
+    |start, end| UInt::range_usize(start..end),
+}
+
+define_uint_in_range_type! {
+    UIntInRangeInclusive,
+    UIntInRangeInclusiveType,
+    UIntInRangeInclusiveTypeWithoutGenerics,
+    UIntInRangeInclusiveTypeWithStart,
+    SerdeRangeInclusive,
+    "..=",
+    |start, end| UInt::range_inclusive_usize(start..=end),
+}
+
+impl SerdeRange<DynSize, DynSize> {
+    fn is_empty(self) -> bool {
+        self.start >= self.end
+    }
+}
+
+impl SerdeRangeInclusive<DynSize, DynSize> {
+    fn is_empty(self) -> bool {
+        self.start > self.end
+    }
+}

crates/fayalite/src/intern.rs

@@ -1,9 +1,9 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 // See Notices.txt for copyright information
 #![allow(clippy::type_complexity)]
-use crate::intern::type_map::TypeIdMap;
+use crate::{intern::type_map::TypeIdMap, util::DefaultBuildHasher};
 use bitvec::{ptr::BitPtr, slice::BitSlice, vec::BitVec};
-use hashbrown::{hash_map::RawEntryMut, HashMap, HashTable};
+use hashbrown::HashTable;
 use serde::{Deserialize, Serialize};
 use std::{
     any::{Any, TypeId},
@@ -17,7 +17,7 @@ use std::{
     sync::{Mutex, RwLock},
 };
 
-pub mod type_map;
+mod type_map;
 
 pub trait LazyInternedTrait<T: ?Sized + Send + Sync + 'static>: Send + Sync + Any {
     fn get(&self) -> Interned<T>;
@@ -316,8 +316,13 @@ pub trait Intern: Any + Send + Sync {
     }
 }
 
+struct InternerState<T: ?Sized + 'static + Send + Sync> {
+    table: HashTable<&'static T>,
+    hasher: DefaultBuildHasher,
+}
+
 pub struct Interner<T: ?Sized + 'static + Send + Sync> {
-    map: Mutex<HashMap<&'static T, ()>>,
+    state: Mutex<InternerState<T>>,
 }
 
 impl<T: ?Sized + 'static + Send + Sync> Interner<T> {
@@ -330,7 +335,10 @@ impl<T: ?Sized + 'static + Send + Sync> Interner<T> {
 impl<T: ?Sized + 'static + Send + Sync> Default for Interner<T> {
     fn default() -> Self {
         Self {
-            map: Default::default(),
+            state: Mutex::new(InternerState {
+                table: HashTable::new(),
+                hasher: Default::default(),
+            }),
         }
     }
 }
@@ -341,17 +349,16 @@ impl<T: ?Sized + 'static + Send + Sync + Hash + Eq + ToOwned> Interner<T> {
         alloc: F,
         value: Cow<'_, T>,
     ) -> Interned<T> {
-        let mut map = self.map.lock().unwrap();
-        let hasher = map.hasher().clone();
-        let hash = hasher.hash_one(&*value);
-        let inner = match map.raw_entry_mut().from_hash(hash, |k| **k == *value) {
-            RawEntryMut::Occupied(entry) => *entry.key(),
-            RawEntryMut::Vacant(entry) => {
-                *entry
-                    .insert_with_hasher(hash, alloc(value), (), |k| hasher.hash_one(&**k))
-                    .0
-            }
-        };
+        let mut state = self.state.lock().unwrap();
+        let InternerState { table, hasher } = &mut *state;
+        let inner = *table
+            .entry(
+                hasher.hash_one(&*value),
+                |k| **k == *value,
+                |k| hasher.hash_one(&**k),
+            )
+            .or_insert_with(|| alloc(value))
+            .get();
         Interned { inner }
     }
 }
@@ -742,7 +749,7 @@ pub trait MemoizeGeneric: 'static + Send + Sync + Hash + Eq + Copy {
     fn get_cow(self, input: Self::InputCow<'_>) -> Self::Output {
         static TYPE_ID_MAP: TypeIdMap = TypeIdMap::new();
         let map: &RwLock<(
-            hashbrown::hash_map::DefaultHashBuilder,
+            DefaultBuildHasher,
             HashTable<(Self, Self::InputOwned, Self::Output)>,
         )> = TYPE_ID_MAP.get_or_insert_default();
         fn hash_eq_key<'a, 'b, T: MemoizeGeneric>(

crates/fayalite/src/intern/type_map.rs

@@ -1,10 +1,8 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 // See Notices.txt for copyright information
-use hashbrown::HashMap;
 use std::{
     any::{Any, TypeId},
     hash::{BuildHasher, Hasher},
-    ptr::NonNull,
     sync::RwLock,
 };
 
@@ -75,59 +73,36 @@ impl BuildHasher for TypeIdBuildHasher {
     }
 }
 
-struct Value(NonNull<dyn Any + Send + Sync>);
-
-impl Value {
-    unsafe fn get_transmute_lifetime<'b>(&self) -> &'b (dyn Any + Send + Sync) {
-        unsafe { &*self.0.as_ptr() }
-    }
-    fn new(v: Box<dyn Any + Send + Sync>) -> Self {
-        unsafe { Self(NonNull::new_unchecked(Box::into_raw(v))) }
-    }
-}
-
-unsafe impl Send for Value {}
-unsafe impl Sync for Value {}
-
-impl Drop for Value {
-    fn drop(&mut self) {
-        unsafe { std::ptr::drop_in_place(self.0.as_ptr()) }
-    }
-}
-
-pub struct TypeIdMap(RwLock<HashMap<TypeId, Value, TypeIdBuildHasher>>);
+pub(crate) struct TypeIdMap(
+    RwLock<hashbrown::HashMap<TypeId, &'static (dyn Any + Send + Sync), TypeIdBuildHasher>>,
+);
 
 impl TypeIdMap {
-    pub const fn new() -> Self {
-        Self(RwLock::new(HashMap::with_hasher(TypeIdBuildHasher)))
+    pub(crate) const fn new() -> Self {
+        Self(RwLock::new(hashbrown::HashMap::with_hasher(
+            TypeIdBuildHasher,
+        )))
     }
     #[cold]
-    unsafe fn insert_slow(
+    fn insert_slow(
         &self,
         type_id: TypeId,
         make: fn() -> Box<dyn Any + Sync + Send>,
-    ) -> &(dyn Any + Sync + Send) {
-        let value = Value::new(make());
+    ) -> &'static (dyn Any + Sync + Send) {
+        let value = Box::leak(make());
         let mut write_guard = self.0.write().unwrap();
-        unsafe {
-            write_guard
-                .entry(type_id)
-                .or_insert(value)
-                .get_transmute_lifetime()
+        *write_guard.entry(type_id).or_insert(value)
     }
-    }
-    pub fn get_or_insert_default<T: Sized + Any + Send + Sync + Default>(&self) -> &T {
+    pub(crate) fn get_or_insert_default<T: Sized + Any + Send + Sync + Default>(&self) -> &T {
         let type_id = TypeId::of::<T>();
         let read_guard = self.0.read().unwrap();
-        let retval = read_guard
-            .get(&type_id)
-            .map(|v| unsafe { Value::get_transmute_lifetime(v) });
+        let retval = read_guard.get(&type_id).map(|v| *v);
         drop(read_guard);
         let retval = match retval {
             Some(retval) => retval,
-            None => unsafe { self.insert_slow(type_id, move || Box::new(T::default())) },
+            None => self.insert_slow(type_id, move || Box::new(T::default())),
         };
-        unsafe { &*(retval as *const dyn Any as *const T) }
+        retval.downcast_ref().expect("known to have correct TypeId")
     }
 }
 

crates/fayalite/src/lib.rs

@@ -76,6 +76,8 @@ pub use fayalite_proc_macros::hdl_module;
 #[doc(inline)]
 pub use fayalite_proc_macros::hdl;
 
+pub use bitvec;
+
 /// struct used as a placeholder when applying defaults
 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
 pub struct __;
@@ -96,6 +98,7 @@ pub mod int;
 pub mod intern;
 pub mod memory;
 pub mod module;
+pub mod phantom_const;
 pub mod prelude;
 pub mod reg;
 pub mod reset;

crates/fayalite/src/memory.rs

@@ -470,7 +470,7 @@ pub enum ReadUnderWrite {
     Undefined,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 struct MemImpl<Element: Type, Len: Size, P> {
     scoped_name: ScopedNameId,
     source_location: SourceLocation,
@@ -1082,6 +1082,7 @@ pub fn splat_mask<T: Type>(ty: T, value: Expr<Bool>) -> Expr<AsMask<T>> {
             )
             .to_expr(),
         )),
+        CanonicalType::PhantomConst(_) => Expr::from_canonical(Expr::canonical(().to_expr())),
     }
 }
 

crates/fayalite/src/module.rs

@@ -21,18 +21,20 @@ use crate::{
     memory::{Mem, MemBuilder, MemBuilderTarget, PortName},
     reg::Reg,
     reset::{AsyncReset, Reset, ResetType, ResetTypeDispatch, SyncReset},
+    sim::{ExternModuleSimGenerator, ExternModuleSimulation},
     source_location::SourceLocation,
     ty::{CanonicalType, Type},
-    util::ScopedRef,
+    util::{HashMap, HashSet, ScopedRef},
     wire::{IncompleteWire, Wire},
 };
-use hashbrown::{hash_map::Entry, HashMap, HashSet};
+use hashbrown::hash_map::Entry;
 use num_bigint::BigInt;
 use std::{
     cell::RefCell,
     collections::VecDeque,
     convert::Infallible,
     fmt,
+    future::IntoFuture,
     hash::{Hash, Hasher},
     iter::FusedIterator,
     marker::PhantomData,
@@ -1081,6 +1083,7 @@ pub struct ExternModuleBody<
 > {
     pub verilog_name: Interned<str>,
     pub parameters: P,
+    pub simulation: Option<ExternModuleSimulation>,
 }
 
 impl From<ExternModuleBody<Vec<ExternModuleParameter>>> for ExternModuleBody {
@@ -1088,11 +1091,13 @@ impl From<ExternModuleBody<Vec<ExternModuleParameter>>> for ExternModuleBody {
         let ExternModuleBody {
             verilog_name,
             parameters,
+            simulation,
         } = value;
         let parameters = Intern::intern_owned(parameters);
         Self {
             verilog_name,
             parameters,
+            simulation,
         }
     }
 }
@@ -1283,10 +1288,12 @@ impl<T: BundleType> fmt::Debug for DebugModuleBody<T> {
             ModuleBody::Extern(ExternModuleBody {
                 verilog_name,
                 parameters,
+                simulation,
             }) => {
                 debug_struct
                     .field("verilog_name", verilog_name)
-                    .field("parameters", parameters);
+                    .field("parameters", parameters)
+                    .field("simulation", simulation);
             }
         }
         debug_struct.finish_non_exhaustive()
@@ -1490,6 +1497,9 @@ impl TargetState {
                         })
                         .collect(),
                 },
+                CanonicalType::PhantomConst(_) => TargetStateInner::Decomposed {
+                    subtargets: HashMap::default(),
+                },
                 CanonicalType::Array(ty) => TargetStateInner::Decomposed {
                     subtargets: (0..ty.len())
                         .map(|index| {
@@ -1758,6 +1768,7 @@ impl AssertValidityState {
             ModuleBody::Extern(ExternModuleBody {
                 verilog_name: _,
                 parameters: _,
+                simulation: _,
             }) => {}
             ModuleBody::Normal(NormalModuleBody { body }) => {
                 let body = self.make_block_index(body);
@@ -1853,7 +1864,7 @@ impl<T: BundleType> Module<T> {
         AssertValidityState {
             module: self.canonical(),
             blocks: vec![],
-            target_states: HashMap::with_capacity(64),
+            target_states: HashMap::with_capacity_and_hasher(64, Default::default()),
         }
         .assert_validity();
     }
@@ -2105,6 +2116,7 @@ impl ModuleBuilder {
             ModuleKind::Extern => ModuleBody::Extern(ExternModuleBody {
                 verilog_name: name.0,
                 parameters: vec![],
+                simulation: None,
             }),
             ModuleKind::Normal => ModuleBody::Normal(NormalModuleBody {
                 body: BuilderModuleBody {
@@ -2113,8 +2125,8 @@ impl ModuleBuilder {
                         incomplete_declarations: vec![],
                         stmts: vec![],
                     }],
-                    annotations_map: HashMap::new(),
-                    memory_map: HashMap::new(),
+                    annotations_map: HashMap::default(),
+                    memory_map: HashMap::default(),
                 },
             }),
         };
@@ -2124,7 +2136,7 @@ impl ModuleBuilder {
             impl_: RefCell::new(ModuleBuilderImpl {
                 body,
                 io: vec![],
-                io_indexes: HashMap::new(),
+                io_indexes: HashMap::default(),
                 module_annotations: vec![],
             }),
         };
@@ -2171,6 +2183,7 @@ impl ModuleBuilder {
             .builder_extern_body()
             .verilog_name = name.intern();
     }
+    #[track_caller]
     pub fn parameter(&self, name: impl AsRef<str>, value: ExternModuleParameterValue) {
         let name = name.as_ref();
         self.impl_
@@ -2183,6 +2196,7 @@ impl ModuleBuilder {
                 value,
             });
     }
+    #[track_caller]
     pub fn parameter_int(&self, name: impl AsRef<str>, value: impl Into<BigInt>) {
         let name = name.as_ref();
         let value = value.into();
@@ -2196,6 +2210,7 @@ impl ModuleBuilder {
                 value: ExternModuleParameterValue::Integer(value),
             });
     }
+    #[track_caller]
     pub fn parameter_str(&self, name: impl AsRef<str>, value: impl AsRef<str>) {
         let name = name.as_ref();
         let value = value.as_ref();
@@ -2209,6 +2224,7 @@ impl ModuleBuilder {
                 value: ExternModuleParameterValue::String(value.intern()),
             });
     }
+    #[track_caller]
     pub fn parameter_raw_verilog(&self, name: impl AsRef<str>, raw_verilog: impl AsRef<str>) {
         let name = name.as_ref();
         let raw_verilog = raw_verilog.as_ref();
@@ -2222,6 +2238,26 @@ impl ModuleBuilder {
                 value: ExternModuleParameterValue::RawVerilog(raw_verilog.intern()),
             });
     }
+    #[track_caller]
+    pub fn extern_module_simulation<G: ExternModuleSimGenerator>(&self, generator: G) {
+        let mut impl_ = self.impl_.borrow_mut();
+        let simulation = &mut impl_.body.builder_extern_body().simulation;
+        if simulation.is_some() {
+            panic!("already added an extern module simulation");
+        }
+        *simulation = Some(ExternModuleSimulation::new(generator));
+    }
+    #[track_caller]
+    pub fn extern_module_simulation_fn<
+        Args: fmt::Debug + Clone + Hash + Eq + Send + Sync + 'static,
+        Fut: IntoFuture<Output = ()> + 'static,
+    >(
+        &self,
+        args: Args,
+        f: fn(Args, crate::sim::ExternModuleSimulationState) -> Fut,
+    ) {
+        self.extern_module_simulation(crate::sim::SimGeneratorFn { args, f });
+    }
 }
 
 #[track_caller]

crates/fayalite/src/module/transform/deduce_resets.rs

@@ -24,8 +24,9 @@ use crate::{
     },
     prelude::*,
     reset::{ResetType, ResetTypeDispatch},
+    util::{HashMap, HashSet},
 };
-use hashbrown::{hash_map::Entry, HashMap, HashSet};
+use hashbrown::hash_map::Entry;
 use num_bigint::BigInt;
 use petgraph::unionfind::UnionFind;
 use std::{fmt, marker::PhantomData};
@@ -155,6 +156,7 @@ impl ResetsLayout {
                     CanonicalType::SyncReset(_) => ResetsLayout::SyncReset,
                     CanonicalType::Reset(_) => ResetsLayout::Reset,
                     CanonicalType::Clock(_) => ResetsLayout::NoResets,
+                    CanonicalType::PhantomConst(_) => ResetsLayout::NoResets,
                 }
             }
         }
@@ -407,7 +409,8 @@ impl Resets {
             | CanonicalType::Bool(_)
             | CanonicalType::AsyncReset(_)
             | CanonicalType::SyncReset(_)
-            | CanonicalType::Clock(_) => Ok(self.ty),
+            | CanonicalType::Clock(_)
+            | CanonicalType::PhantomConst(_) => Ok(self.ty),
             CanonicalType::Array(ty) => Ok(CanonicalType::Array(Array::new_dyn(
                 self.array_elements().substituted_type(
                     reset_graph,
@@ -998,7 +1001,8 @@ fn cast_bit_op<P: Pass, T: Type, A: Type>(
                             CanonicalType::Array(_)
                             | CanonicalType::Enum(_)
                             | CanonicalType::Bundle(_)
-                            | CanonicalType::Reset(_) => unreachable!(),
+                            | CanonicalType::Reset(_)
+                            | CanonicalType::PhantomConst(_) => unreachable!(),
                             $(CanonicalType::$Variant(ty) => Expr::expr_enum($arg.cast_to(ty)),)*
                         }
                     };
@@ -1010,6 +1014,7 @@ fn cast_bit_op<P: Pass, T: Type, A: Type>(
                             | CanonicalType::Enum(_)
                             | CanonicalType::Bundle(_)
                             | CanonicalType::Reset(_) => unreachable!(),
+                            CanonicalType::PhantomConst(_) => Expr::expr_enum(arg),
                             $(CanonicalType::$Variant(_) => {
                                 let arg = Expr::<$Variant>::from_canonical(arg);
                                 match_expr_ty!(arg, UInt, SInt, Bool, AsyncReset, SyncReset, Clock)
@@ -1040,6 +1045,7 @@ impl<P: Pass> RunPass<P> for ExprEnum {
             ExprEnum::UIntLiteral(expr) => Ok(expr.run_pass(pass_args)?.map(ExprEnum::from)),
             ExprEnum::SIntLiteral(expr) => Ok(expr.run_pass(pass_args)?.map(ExprEnum::from)),
             ExprEnum::BoolLiteral(expr) => Ok(expr.run_pass(pass_args)?.map(ExprEnum::from)),
+            ExprEnum::PhantomConst(expr) => Ok(expr.run_pass(pass_args)?.map(ExprEnum::from)),
             ExprEnum::BundleLiteral(expr) => Ok(expr.run_pass(pass_args)?.map(ExprEnum::from)),
             ExprEnum::ArrayLiteral(expr) => Ok(expr.run_pass(pass_args)?.map(ExprEnum::from)),
             ExprEnum::EnumLiteral(expr) => Ok(expr.run_pass(pass_args)?.map(ExprEnum::from)),
@@ -1670,7 +1676,8 @@ impl RunPassDispatch for AnyReg {
                 | CanonicalType::Enum(_)
                 | CanonicalType::Bundle(_)
                 | CanonicalType::Reset(_)
-                | CanonicalType::Clock(_) => unreachable!(),
+                | CanonicalType::Clock(_)
+                | CanonicalType::PhantomConst(_) => unreachable!(),
             }
         })
     }
@@ -1769,6 +1776,7 @@ impl_run_pass_copy!([] SVAttributeAnnotation);
 impl_run_pass_copy!([] UInt);
 impl_run_pass_copy!([] usize);
 impl_run_pass_copy!([] FormalKind);
+impl_run_pass_copy!([] PhantomConst);
 
 macro_rules! impl_run_pass_for_struct {
     (
@@ -2244,9 +2252,9 @@ pub fn deduce_resets(
     fallback_to_sync_reset: bool,
 ) -> Result<Interned<Module<Bundle>>, DeduceResetsError> {
     let mut state = State {
-        modules_added_to_graph: HashSet::new(),
-        substituted_modules: HashMap::new(),
-        expr_resets: HashMap::new(),
+        modules_added_to_graph: HashSet::default(),
+        substituted_modules: HashMap::default(),
+        expr_resets: HashMap::default(),
         reset_graph: ResetGraph::default(),
         fallback_to_sync_reset,
     };

crates/fayalite/src/module/transform/simplify_enums.rs

@@ -18,10 +18,10 @@ use crate::{
     },
     source_location::SourceLocation,
     ty::{CanonicalType, Type},
+    util::HashMap,
     wire::Wire,
 };
 use core::fmt;
-use hashbrown::HashMap;
 
 #[derive(Debug)]
 pub enum SimplifyEnumsError {
@@ -69,7 +69,8 @@ fn contains_any_enum_types(ty: CanonicalType) -> bool {
                 | CanonicalType::AsyncReset(_)
                 | CanonicalType::SyncReset(_)
                 | CanonicalType::Reset(_)
-                | CanonicalType::Clock(_) => false,
+                | CanonicalType::Clock(_)
+                | CanonicalType::PhantomConst(_) => false,
             }
         }
     }
@@ -512,7 +513,8 @@ impl State {
             | CanonicalType::AsyncReset(_)
             | CanonicalType::SyncReset(_)
             | CanonicalType::Reset(_)
-            | CanonicalType::Clock(_) => unreachable!(),
+            | CanonicalType::Clock(_)
+            | CanonicalType::PhantomConst(_) => unreachable!(),
         }
     }
 }
@@ -577,7 +579,8 @@ fn connect_port(
         | (CanonicalType::Clock(_), _)
         | (CanonicalType::AsyncReset(_), _)
         | (CanonicalType::SyncReset(_), _)
-        | (CanonicalType::Reset(_), _) => unreachable!(
+        | (CanonicalType::Reset(_), _)
+        | (CanonicalType::PhantomConst(_), _) => unreachable!(
             "trying to connect memory ports:\n{:?}\n{:?}",
             Expr::ty(lhs),
             Expr::ty(rhs),
@@ -665,6 +668,7 @@ impl Folder for State {
             ExprEnum::UIntLiteral(_)
             | ExprEnum::SIntLiteral(_)
             | ExprEnum::BoolLiteral(_)
+            | ExprEnum::PhantomConst(_)
             | ExprEnum::BundleLiteral(_)
             | ExprEnum::ArrayLiteral(_)
             | ExprEnum::Uninit(_)
@@ -923,7 +927,8 @@ impl Folder for State {
             | CanonicalType::Clock(_)
             | CanonicalType::AsyncReset(_)
             | CanonicalType::SyncReset(_)
-            | CanonicalType::Reset(_) => canonical_type.default_fold(self),
+            | CanonicalType::Reset(_)
+            | CanonicalType::PhantomConst(_) => canonical_type.default_fold(self),
         }
     }
 
@@ -960,8 +965,8 @@ pub fn simplify_enums(
     kind: SimplifyEnumsKind,
 ) -> Result<Interned<Module<Bundle>>, SimplifyEnumsError> {
     module.fold(&mut State {
-        enum_types: HashMap::new(),
-        replacement_mem_ports: HashMap::new(),
+        enum_types: HashMap::default(),
+        replacement_mem_ports: HashMap::default(),
         kind,
         module_state_stack: vec![],
     })

crates/fayalite/src/module/transform/simplify_memories.rs

@@ -14,11 +14,10 @@ use crate::{
     },
     source_location::SourceLocation,
     ty::{CanonicalType, Type},
-    util::MakeMutSlice,
+    util::{HashMap, MakeMutSlice},
     wire::Wire,
 };
 use bitvec::{slice::BitSlice, vec::BitVec};
-use hashbrown::HashMap;
 use std::{
     convert::Infallible,
     fmt::Write,
@@ -62,6 +61,7 @@ enum MemSplit {
     Bundle {
         fields: Rc<[MemSplit]>,
     },
+    PhantomConst,
     Single {
         output_mem: Option<Mem>,
         element_type: SingleType,
@@ -76,6 +76,7 @@ impl MemSplit {
     fn mark_changed_element_type(self) -> Self {
         match self {
             MemSplit::Bundle { fields: _ } => self,
+            MemSplit::PhantomConst => self,
             MemSplit::Single {
                 output_mem,
                 element_type,
@@ -97,6 +98,7 @@ impl MemSplit {
                     .map(|field| Self::new(field.ty).mark_changed_element_type())
                     .collect(),
             },
+            CanonicalType::PhantomConst(_) => MemSplit::PhantomConst,
             CanonicalType::Array(ty) => {
                 let element = MemSplit::new(ty.element());
                 if let Self::Single {
@@ -339,6 +341,7 @@ impl SplitMemState<'_, '_> {
                     self.split_state_stack.pop();
                 }
             }
+            MemSplit::PhantomConst => {}
             MemSplit::Single {
                 output_mem,
                 element_type: single_type,
@@ -538,7 +541,12 @@ impl ModuleState {
             };
         loop {
             match input_element_type {
-                CanonicalType::Bundle(_) => unreachable!("bundle types are always split"),
+                CanonicalType::Bundle(_) => {
+                    unreachable!("bundle types are always split")
+                }
+                CanonicalType::PhantomConst(_) => {
+                    unreachable!("PhantomConst are always removed")
+                }
                 CanonicalType::Enum(_)
                     if input_array_types
                         .first()
@@ -743,7 +751,8 @@ impl ModuleState {
                 ..
             }
             | MemSplit::Bundle { .. }
-            | MemSplit::Array { .. } => {
+            | MemSplit::Array { .. }
+            | MemSplit::PhantomConst => {
                 let mut replacement_ports = Vec::with_capacity(input_mem.ports().len());
                 let mut wire_port_rdata = Vec::with_capacity(input_mem.ports().len());
                 let mut wire_port_wdata = Vec::with_capacity(input_mem.ports().len());
@@ -887,7 +896,7 @@ impl Folder for State {
             module,
             ModuleState {
                 output_module: None,
-                memories: HashMap::new(),
+                memories: HashMap::default(),
             },
         );
         let mut this = PushedState::push_module(self, module);

crates/fayalite/src/module/transform/visit.rs

@@ -28,8 +28,10 @@ use crate::{
         NormalModuleBody, ScopedNameId, Stmt, StmtConnect, StmtDeclaration, StmtFormal, StmtIf,
         StmtInstance, StmtMatch, StmtReg, StmtWire,
     },
+    phantom_const::PhantomConst,
     reg::Reg,
     reset::{AsyncReset, Reset, ResetType, SyncReset},
+    sim::ExternModuleSimulation,
     source_location::SourceLocation,
     ty::{CanonicalType, Type},
     wire::Wire,

crates/fayalite/src/phantom_const.rs

@@ -0,0 +1,410 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+use crate::{
+    expr::{
+        ops::{ExprPartialEq, ExprPartialOrd},
+        Expr, ToExpr,
+    },
+    int::Bool,
+    intern::{Intern, Interned, InternedCompare, LazyInterned, LazyInternedTrait, Memoize},
+    sim::value::{SimValue, SimValuePartialEq, ToSimValue, ToSimValueWithType},
+    source_location::SourceLocation,
+    ty::{
+        impl_match_variant_as_self,
+        serde_impls::{SerdeCanonicalType, SerdePhantomConst},
+        CanonicalType, StaticType, Type, TypeProperties,
+    },
+};
+use bitvec::slice::BitSlice;
+use serde::{
+    de::{DeserializeOwned, Error},
+    Deserialize, Deserializer, Serialize, Serializer,
+};
+use std::{
+    any::Any,
+    fmt,
+    hash::{Hash, Hasher},
+    marker::PhantomData,
+    ops::Index,
+};
+
+#[derive(Clone)]
+pub struct PhantomConstCanonicalValue {
+    parsed: serde_json::Value,
+    serialized: Interned<str>,
+}
+
+impl PhantomConstCanonicalValue {
+    pub fn from_json_value(parsed: serde_json::Value) -> Self {
+        let serialized = Intern::intern_owned(
+            serde_json::to_string(&parsed)
+                .expect("conversion from json value to text shouldn't fail"),
+        );
+        Self { parsed, serialized }
+    }
+    pub fn as_json_value(&self) -> &serde_json::Value {
+        &self.parsed
+    }
+    pub fn as_str(&self) -> Interned<str> {
+        self.serialized
+    }
+}
+
+impl fmt::Debug for PhantomConstCanonicalValue {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&self.serialized)
+    }
+}
+
+impl fmt::Display for PhantomConstCanonicalValue {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&self.serialized)
+    }
+}
+
+impl PartialEq for PhantomConstCanonicalValue {
+    fn eq(&self, other: &Self) -> bool {
+        self.serialized == other.serialized
+    }
+}
+
+impl Eq for PhantomConstCanonicalValue {}
+
+impl Hash for PhantomConstCanonicalValue {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.serialized.hash(state);
+    }
+}
+
+impl Serialize for PhantomConstCanonicalValue {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        self.parsed.serialize(serializer)
+    }
+}
+
+impl<'de> Deserialize<'de> for PhantomConstCanonicalValue {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        Ok(Self::from_json_value(serde_json::Value::deserialize(
+            deserializer,
+        )?))
+    }
+}
+
+pub trait PhantomConstValue: Intern + InternedCompare + Serialize + fmt::Debug {
+    fn deserialize_value<'de, D>(deserializer: D) -> Result<Interned<Self>, D::Error>
+    where
+        D: serde::Deserializer<'de>;
+}
+
+impl<T> PhantomConstValue for T
+where
+    T: ?Sized + Intern + InternedCompare + Serialize + fmt::Debug,
+    Interned<T>: DeserializeOwned,
+{
+    fn deserialize_value<'de, D>(deserializer: D) -> Result<Interned<Self>, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        <Interned<T> as Deserialize<'de>>::deserialize(deserializer)
+    }
+}
+
+/// Wrapper type that allows any Rust value to be smuggled as a HDL [`Type`].
+/// This only works for values that can be [serialized][Serialize] to and [deserialized][Deserialize] from [JSON][serde_json].
+pub struct PhantomConst<T: ?Sized + PhantomConstValue = PhantomConstCanonicalValue> {
+    value: LazyInterned<T>,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Default)]
+pub struct PhantomConstWithoutGenerics;
+
+#[allow(non_upper_case_globals)]
+pub const PhantomConst: PhantomConstWithoutGenerics = PhantomConstWithoutGenerics;
+
+impl<T: Type + PhantomConstValue> Index<T> for PhantomConstWithoutGenerics {
+    type Output = PhantomConst<T>;
+
+    fn index(&self, value: T) -> &Self::Output {
+        Interned::into_inner(PhantomConst::new(value.intern()).intern_sized())
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> fmt::Debug for PhantomConst<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("PhantomConst").field(&self.get()).finish()
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> Clone for PhantomConst<T> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> Copy for PhantomConst<T> {}
+
+impl<T: ?Sized + PhantomConstValue> PartialEq for PhantomConst<T> {
+    fn eq(&self, other: &Self) -> bool {
+        self.get() == other.get()
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> Eq for PhantomConst<T> {}
+
+impl<T: ?Sized + PhantomConstValue> Hash for PhantomConst<T> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.get().hash(state);
+    }
+}
+
+struct PhantomConstCanonicalMemoize<T: ?Sized, const IS_FROM_CANONICAL: bool>(PhantomData<T>);
+
+impl<T: ?Sized, const IS_FROM_CANONICAL: bool> Copy
+    for PhantomConstCanonicalMemoize<T, IS_FROM_CANONICAL>
+{
+}
+
+impl<T: ?Sized, const IS_FROM_CANONICAL: bool> Clone
+    for PhantomConstCanonicalMemoize<T, IS_FROM_CANONICAL>
+{
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+impl<T: ?Sized, const IS_FROM_CANONICAL: bool> Eq
+    for PhantomConstCanonicalMemoize<T, IS_FROM_CANONICAL>
+{
+}
+
+impl<T: ?Sized, const IS_FROM_CANONICAL: bool> PartialEq
+    for PhantomConstCanonicalMemoize<T, IS_FROM_CANONICAL>
+{
+    fn eq(&self, _other: &Self) -> bool {
+        true
+    }
+}
+
+impl<T: ?Sized, const IS_FROM_CANONICAL: bool> Hash
+    for PhantomConstCanonicalMemoize<T, IS_FROM_CANONICAL>
+{
+    fn hash<H: Hasher>(&self, _state: &mut H) {}
+}
+
+impl<T: ?Sized + PhantomConstValue> Memoize for PhantomConstCanonicalMemoize<T, false> {
+    type Input = Interned<T>;
+    type InputOwned = Interned<T>;
+    type Output = Interned<PhantomConstCanonicalValue>;
+
+    fn inner(self, input: &Self::Input) -> Self::Output {
+        Intern::intern_sized(PhantomConstCanonicalValue::from_json_value(
+            serde_json::to_value(input)
+                .expect("serialization failed when constructing a canonical PhantomConst"),
+        ))
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> Memoize for PhantomConstCanonicalMemoize<T, true> {
+    type Input = Interned<PhantomConstCanonicalValue>;
+    type InputOwned = Interned<PhantomConstCanonicalValue>;
+    type Output = Interned<T>;
+
+    fn inner(self, input: &Self::Input) -> Self::Output {
+        PhantomConstValue::deserialize_value(input.as_json_value())
+            .expect("deserialization failed ")
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> PhantomConst<T> {
+    pub fn new(value: Interned<T>) -> Self {
+        Self {
+            value: LazyInterned::Interned(value),
+        }
+    }
+    pub const fn new_lazy(v: &'static dyn LazyInternedTrait<T>) -> Self {
+        Self {
+            value: LazyInterned::new_lazy(v),
+        }
+    }
+    pub fn get(self) -> Interned<T> {
+        self.value.interned()
+    }
+    pub fn type_properties(self) -> TypeProperties {
+        <()>::TYPE_PROPERTIES
+    }
+    pub fn can_connect(self, other: Self) -> bool {
+        self == other
+    }
+    pub fn canonical_phantom_const(self) -> PhantomConst {
+        if let Some(&retval) = <dyn Any>::downcast_ref::<PhantomConst>(&self) {
+            return retval;
+        }
+        <PhantomConst>::new(
+            PhantomConstCanonicalMemoize::<T, false>(PhantomData).get_owned(self.get()),
+        )
+    }
+    pub fn from_canonical_phantom_const(canonical_type: PhantomConst) -> Self {
+        if let Some(&retval) = <dyn Any>::downcast_ref::<Self>(&canonical_type) {
+            return retval;
+        }
+        Self::new(
+            PhantomConstCanonicalMemoize::<T, true>(PhantomData).get_owned(canonical_type.get()),
+        )
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> Type for PhantomConst<T> {
+    type BaseType = PhantomConst;
+    type MaskType = ();
+    type SimValue = PhantomConst<T>;
+    impl_match_variant_as_self!();
+
+    fn mask_type(&self) -> Self::MaskType {
+        ()
+    }
+
+    fn canonical(&self) -> CanonicalType {
+        CanonicalType::PhantomConst(self.canonical_phantom_const())
+    }
+
+    fn from_canonical(canonical_type: CanonicalType) -> Self {
+        let CanonicalType::PhantomConst(phantom_const) = canonical_type else {
+            panic!("expected PhantomConst");
+        };
+        Self::from_canonical_phantom_const(phantom_const)
+    }
+
+    fn source_location() -> SourceLocation {
+        SourceLocation::builtin()
+    }
+
+    fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+        assert!(bits.is_empty());
+        *self
+    }
+
+    fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+        assert!(bits.is_empty());
+        assert_eq!(*value, *self);
+    }
+
+    fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+        assert!(bits.is_empty());
+        assert_eq!(*value, *self);
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> Default for PhantomConst<T>
+where
+    Interned<T>: Default,
+{
+    fn default() -> Self {
+        Self::TYPE
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> StaticType for PhantomConst<T>
+where
+    Interned<T>: Default,
+{
+    const TYPE: Self = PhantomConst {
+        value: LazyInterned::new_lazy(&Interned::<T>::default),
+    };
+    const MASK_TYPE: Self::MaskType = ();
+    const TYPE_PROPERTIES: TypeProperties = <()>::TYPE_PROPERTIES;
+    const MASK_TYPE_PROPERTIES: TypeProperties = <()>::TYPE_PROPERTIES;
+}
+
+type SerdeType<T> = SerdeCanonicalType<CanonicalType, SerdePhantomConst<Interned<T>>>;
+
+impl<T: ?Sized + PhantomConstValue> Serialize for PhantomConst<T> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        SerdeType::<T>::PhantomConst(SerdePhantomConst(self.get())).serialize(serializer)
+    }
+}
+
+impl<'de, T: ?Sized + PhantomConstValue> Deserialize<'de> for PhantomConst<T> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        match SerdeType::<T>::deserialize(deserializer)? {
+            SerdeCanonicalType::PhantomConst(SerdePhantomConst(value)) => Ok(Self::new(value)),
+            ty => Err(Error::invalid_value(
+                serde::de::Unexpected::Other(ty.as_serde_unexpected_str()),
+                &"a PhantomConst",
+            )),
+        }
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> ExprPartialEq<Self> for PhantomConst<T> {
+    fn cmp_eq(lhs: Expr<Self>, rhs: Expr<Self>) -> Expr<Bool> {
+        assert_eq!(Expr::ty(lhs), Expr::ty(rhs));
+        true.to_expr()
+    }
+
+    fn cmp_ne(lhs: Expr<Self>, rhs: Expr<Self>) -> Expr<Bool> {
+        assert_eq!(Expr::ty(lhs), Expr::ty(rhs));
+        false.to_expr()
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> ExprPartialOrd<Self> for PhantomConst<T> {
+    fn cmp_lt(lhs: Expr<Self>, rhs: Expr<Self>) -> Expr<Bool> {
+        assert_eq!(Expr::ty(lhs), Expr::ty(rhs));
+        false.to_expr()
+    }
+
+    fn cmp_le(lhs: Expr<Self>, rhs: Expr<Self>) -> Expr<Bool> {
+        assert_eq!(Expr::ty(lhs), Expr::ty(rhs));
+        true.to_expr()
+    }
+
+    fn cmp_gt(lhs: Expr<Self>, rhs: Expr<Self>) -> Expr<Bool> {
+        assert_eq!(Expr::ty(lhs), Expr::ty(rhs));
+        false.to_expr()
+    }
+
+    fn cmp_ge(lhs: Expr<Self>, rhs: Expr<Self>) -> Expr<Bool> {
+        assert_eq!(Expr::ty(lhs), Expr::ty(rhs));
+        true.to_expr()
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> SimValuePartialEq<Self> for PhantomConst<T> {
+    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<Self>) -> bool {
+        assert_eq!(SimValue::ty(this), SimValue::ty(other));
+        true
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> ToSimValue for PhantomConst<T> {
+    type Type = PhantomConst<T>;
+
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        SimValue::from_value(*self, *self)
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> ToSimValueWithType<PhantomConst<T>> for PhantomConst<T> {
+    fn to_sim_value_with_type(&self, ty: PhantomConst<T>) -> SimValue<PhantomConst<T>> {
+        SimValue::from_value(ty, *self)
+    }
+}
+
+impl<T: ?Sized + PhantomConstValue> ToSimValueWithType<CanonicalType> for PhantomConst<T> {
+    fn to_sim_value_with_type(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
+        SimValue::into_canonical(SimValue::from_value(Self::from_canonical(ty), *self))
+    }
+}

crates/fayalite/src/prelude.rs

@@ -20,17 +20,24 @@ pub use crate::{
         hdl_cover_with_enable, MakeFormalExpr,
     },
     hdl, hdl_module,
-    int::{Bool, DynSize, KnownSize, SInt, SIntType, Size, UInt, UIntType},
+    int::{Bool, DynSize, KnownSize, SInt, SIntType, SIntValue, Size, UInt, UIntType, UIntValue},
     memory::{Mem, MemBuilder, ReadUnderWrite},
     module::{
         annotate, connect, connect_any, incomplete_wire, instance, memory, memory_array,
         memory_with_init, reg_builder, wire, Instance, Module, ModuleBuilder,
     },
+    phantom_const::PhantomConst,
     reg::Reg,
     reset::{AsyncReset, Reset, SyncReset, ToAsyncReset, ToReset, ToSyncReset},
+    sim::{
+        time::{SimDuration, SimInstant},
+        value::{SimValue, ToSimValue, ToSimValueWithType},
+        ExternModuleSimulationState, Simulation,
+    },
     source_location::SourceLocation,
     ty::{AsMask, CanonicalType, Type},
     util::{ConstUsize, GenericConstUsize},
     wire::Wire,
     __,
 };
+pub use bitvec::{slice::BitSlice, vec::BitVec};

crates/fayalite/src/reset.rs

@@ -7,6 +7,7 @@ use crate::{
     source_location::SourceLocation,
     ty::{impl_match_variant_as_self, CanonicalType, StaticType, Type, TypeProperties},
 };
+use bitvec::slice::BitSlice;
 
 mod sealed {
     pub trait ResetTypeSealed {}
@@ -45,6 +46,7 @@ macro_rules! reset_type {
         impl Type for $name {
             type BaseType = $name;
             type MaskType = Bool;
+            type SimValue = bool;
 
             impl_match_variant_as_self!();
 
@@ -66,6 +68,21 @@ macro_rules! reset_type {
                 };
                 retval
             }
+
+            fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+                assert_eq!(bits.len(), 1);
+                bits[0]
+            }
+
+            fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+                assert_eq!(bits.len(), 1);
+                *value = bits[0];
+            }
+
+            fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+                assert_eq!(bits.len(), 1);
+                bits.set(0, *value);
+            }
         }
 
         impl $name {

crates/fayalite/src/sim/interpreter.rs

@@ -7,10 +7,9 @@ use crate::{
     intern::{Intern, Interned, Memoize},
     source_location::SourceLocation,
     ty::CanonicalType,
-    util::get_many_mut,
+    util::{get_many_mut, HashMap, HashSet},
 };
 use bitvec::{boxed::BitBox, slice::BitSlice};
-use hashbrown::{HashMap, HashSet};
 use num_bigint::BigInt;
 use num_traits::{One, Signed, ToPrimitive, Zero};
 use std::{

crates/fayalite/src/sim/value.rs

@@ -0,0 +1,913 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+use crate::{
+    array::{Array, ArrayType},
+    bundle::{Bundle, BundleType},
+    clock::Clock,
+    enum_::{Enum, EnumType},
+    expr::{CastBitsTo, Expr, ToExpr},
+    int::{Bool, IntType, KnownSize, SInt, SIntType, SIntValue, Size, UInt, UIntType, UIntValue},
+    reset::{AsyncReset, Reset, SyncReset},
+    ty::{CanonicalType, StaticType, Type},
+    util::{
+        alternating_cell::{AlternatingCell, AlternatingCellMethods},
+        ConstUsize,
+    },
+};
+use bitvec::{slice::BitSlice, vec::BitVec};
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use std::{
+    fmt,
+    ops::{Deref, DerefMut},
+    sync::Arc,
+};
+
+#[derive(Copy, Clone, Eq, PartialEq)]
+enum ValidFlags {
+    BothValid = 0,
+    OnlyValueValid = 1,
+    OnlyBitsValid = 2,
+}
+
+#[derive(Clone)]
+struct SimValueInner<T: Type> {
+    value: T::SimValue,
+    bits: UIntValue,
+    valid_flags: ValidFlags,
+    ty: T,
+}
+
+impl<T: Type> SimValueInner<T> {
+    fn fill_bits(&mut self) {
+        match self.valid_flags {
+            ValidFlags::BothValid | ValidFlags::OnlyBitsValid => {}
+            ValidFlags::OnlyValueValid => {
+                self.ty.sim_value_to_bits(&self.value, self.bits.bits_mut());
+                self.valid_flags = ValidFlags::BothValid;
+            }
+        }
+    }
+    fn into_bits(mut self) -> UIntValue {
+        self.fill_bits();
+        self.bits
+    }
+    fn bits_mut(&mut self) -> &mut UIntValue {
+        self.fill_bits();
+        self.valid_flags = ValidFlags::OnlyBitsValid;
+        &mut self.bits
+    }
+    fn fill_value(&mut self) {
+        match self.valid_flags {
+            ValidFlags::BothValid | ValidFlags::OnlyValueValid => {}
+            ValidFlags::OnlyBitsValid => {
+                self.ty
+                    .sim_value_clone_from_bits(&mut self.value, self.bits.bits());
+                self.valid_flags = ValidFlags::BothValid;
+            }
+        }
+    }
+    fn into_value(mut self) -> T::SimValue {
+        self.fill_value();
+        self.value
+    }
+    fn value_mut(&mut self) -> &mut T::SimValue {
+        self.fill_value();
+        self.valid_flags = ValidFlags::OnlyValueValid;
+        &mut self.value
+    }
+}
+
+impl<T: Type> AlternatingCellMethods for SimValueInner<T> {
+    fn unique_to_shared(&mut self) {
+        match self.valid_flags {
+            ValidFlags::BothValid => return,
+            ValidFlags::OnlyValueValid => {
+                self.ty.sim_value_to_bits(&self.value, self.bits.bits_mut())
+            }
+            ValidFlags::OnlyBitsValid => self
+                .ty
+                .sim_value_clone_from_bits(&mut self.value, self.bits.bits()),
+        }
+        self.valid_flags = ValidFlags::BothValid;
+    }
+
+    fn shared_to_unique(&mut self) {}
+}
+
+#[derive(Serialize, Deserialize)]
+#[serde(rename = "SimValue")]
+#[serde(bound(
+    serialize = "T: Type<SimValue: Serialize> + Serialize",
+    deserialize = "T: Type<SimValue: Deserialize<'de>> + Deserialize<'de>"
+))]
+struct SerdeSimValue<'a, T: Type> {
+    ty: T,
+    value: std::borrow::Cow<'a, T::SimValue>,
+}
+
+impl<T: Type<SimValue: Serialize> + Serialize> Serialize for SimValue<T> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        SerdeSimValue {
+            ty: SimValue::ty(self),
+            value: std::borrow::Cow::Borrowed(&*self),
+        }
+        .serialize(serializer)
+    }
+}
+
+impl<'de, T: Type<SimValue: Deserialize<'de>> + Deserialize<'de>> Deserialize<'de> for SimValue<T> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let SerdeSimValue { ty, value } = SerdeSimValue::<T>::deserialize(deserializer)?;
+        Ok(SimValue::from_value(ty, value.into_owned()))
+    }
+}
+
+pub struct SimValue<T: Type> {
+    inner: AlternatingCell<SimValueInner<T>>,
+}
+
+impl<T: Type + Clone> Clone for SimValue<T> {
+    fn clone(&self) -> Self {
+        Self {
+            inner: AlternatingCell::new_unique(self.inner.share().clone()),
+        }
+    }
+}
+
+impl<T: Type> SimValue<T> {
+    #[track_caller]
+    pub fn from_bits(ty: T, bits: UIntValue) -> Self {
+        assert_eq!(ty.canonical().bit_width(), bits.width());
+        let inner = SimValueInner {
+            value: ty.sim_value_from_bits(bits.bits()),
+            bits,
+            valid_flags: ValidFlags::BothValid,
+            ty,
+        };
+        Self {
+            inner: AlternatingCell::new_shared(inner),
+        }
+    }
+    #[track_caller]
+    pub fn from_bitslice(ty: T, bits: &BitSlice) -> Self {
+        Self::from_bits(ty, UIntValue::new(Arc::new(bits.to_bitvec())))
+    }
+    pub fn from_value(ty: T, value: T::SimValue) -> Self {
+        let inner = SimValueInner {
+            bits: UIntValue::new_dyn(Arc::new(BitVec::repeat(false, ty.canonical().bit_width()))),
+            value,
+            valid_flags: ValidFlags::OnlyValueValid,
+            ty,
+        };
+        Self {
+            inner: AlternatingCell::new_unique(inner),
+        }
+    }
+    pub fn ty(this: &Self) -> T {
+        this.inner.share().ty
+    }
+    pub fn into_bits(this: Self) -> UIntValue {
+        this.inner.into_inner().into_bits()
+    }
+    pub fn into_ty_and_bits(this: Self) -> (T, UIntValue) {
+        let inner = this.inner.into_inner();
+        (inner.ty, inner.into_bits())
+    }
+    pub fn bits(this: &Self) -> &UIntValue {
+        &this.inner.share().bits
+    }
+    pub fn bits_mut(this: &mut Self) -> &mut UIntValue {
+        this.inner.unique().bits_mut()
+    }
+    pub fn into_value(this: Self) -> T::SimValue {
+        this.inner.into_inner().into_value()
+    }
+    pub fn value(this: &Self) -> &T::SimValue {
+        &this.inner.share().value
+    }
+    pub fn value_mut(this: &mut Self) -> &mut T::SimValue {
+        this.inner.unique().value_mut()
+    }
+    #[track_caller]
+    pub fn from_canonical(v: SimValue<CanonicalType>) -> Self {
+        let (ty, bits) = SimValue::into_ty_and_bits(v);
+        Self::from_bits(T::from_canonical(ty), bits)
+    }
+    pub fn into_canonical(this: Self) -> SimValue<CanonicalType> {
+        let (ty, bits) = Self::into_ty_and_bits(this);
+        SimValue::from_bits(ty.canonical(), bits)
+    }
+    pub fn canonical(this: &Self) -> SimValue<CanonicalType> {
+        SimValue::from_bits(Self::ty(this).canonical(), Self::bits(this).clone())
+    }
+    #[track_caller]
+    pub fn from_dyn_int(v: SimValue<T::Dyn>) -> Self
+    where
+        T: IntType,
+    {
+        let (ty, bits) = SimValue::into_ty_and_bits(v);
+        SimValue::from_bits(T::from_dyn_int(ty), bits)
+    }
+    pub fn into_dyn_int(this: Self) -> SimValue<T::Dyn>
+    where
+        T: IntType,
+    {
+        let (ty, bits) = Self::into_ty_and_bits(this);
+        SimValue::from_bits(ty.as_dyn_int(), bits)
+    }
+    pub fn to_dyn_int(this: &Self) -> SimValue<T::Dyn>
+    where
+        T: IntType,
+    {
+        SimValue::from_bits(Self::ty(this).as_dyn_int(), Self::bits(&this).clone())
+    }
+    #[track_caller]
+    pub fn from_bundle(v: SimValue<Bundle>) -> Self
+    where
+        T: BundleType,
+    {
+        let (ty, bits) = SimValue::into_ty_and_bits(v);
+        SimValue::from_bits(T::from_canonical(CanonicalType::Bundle(ty)), bits)
+    }
+    pub fn into_bundle(this: Self) -> SimValue<Bundle>
+    where
+        T: BundleType,
+    {
+        let (ty, bits) = Self::into_ty_and_bits(this);
+        SimValue::from_bits(Bundle::from_canonical(ty.canonical()), bits)
+    }
+    pub fn to_bundle(this: &Self) -> SimValue<Bundle>
+    where
+        T: BundleType,
+    {
+        SimValue::from_bits(
+            Bundle::from_canonical(Self::ty(this).canonical()),
+            Self::bits(&this).clone(),
+        )
+    }
+    #[track_caller]
+    pub fn from_enum(v: SimValue<Enum>) -> Self
+    where
+        T: EnumType,
+    {
+        let (ty, bits) = SimValue::into_ty_and_bits(v);
+        SimValue::from_bits(T::from_canonical(CanonicalType::Enum(ty)), bits)
+    }
+    pub fn into_enum(this: Self) -> SimValue<Enum>
+    where
+        T: EnumType,
+    {
+        let (ty, bits) = Self::into_ty_and_bits(this);
+        SimValue::from_bits(Enum::from_canonical(ty.canonical()), bits)
+    }
+    pub fn to_enum(this: &Self) -> SimValue<Enum>
+    where
+        T: EnumType,
+    {
+        SimValue::from_bits(
+            Enum::from_canonical(Self::ty(this).canonical()),
+            Self::bits(&this).clone(),
+        )
+    }
+}
+
+impl<T: Type> Deref for SimValue<T> {
+    type Target = T::SimValue;
+
+    fn deref(&self) -> &Self::Target {
+        Self::value(self)
+    }
+}
+
+impl<T: Type> DerefMut for SimValue<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        Self::value_mut(self)
+    }
+}
+
+impl<T: Type> fmt::Debug for SimValue<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let inner = self.inner.share();
+        f.debug_struct("SimValue")
+            .field("ty", &inner.ty)
+            .field("value", &inner.value)
+            .finish()
+    }
+}
+
+impl<T: Type> ToExpr for SimValue<T> {
+    type Type = T;
+
+    #[track_caller]
+    fn to_expr(&self) -> Expr<Self::Type> {
+        let inner = self.inner.share();
+        inner.bits.cast_bits_to(inner.ty)
+    }
+}
+
+pub trait SimValuePartialEq<T: Type = Self>: Type {
+    #[track_caller]
+    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<T>) -> bool;
+}
+
+impl<T: SimValuePartialEq<U>, U: Type> PartialEq<SimValue<U>> for SimValue<T> {
+    #[track_caller]
+    fn eq(&self, other: &SimValue<U>) -> bool {
+        T::sim_value_eq(self, other)
+    }
+}
+
+impl<Width: Size> SimValuePartialEq<Self> for UIntType<Width> {
+    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<Self>) -> bool {
+        **this == **other
+    }
+}
+
+impl<Width: Size> SimValuePartialEq<Self> for SIntType<Width> {
+    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<Self>) -> bool {
+        **this == **other
+    }
+}
+
+impl SimValuePartialEq<Bool> for Bool {
+    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<Bool>) -> bool {
+        **this == **other
+    }
+}
+
+pub trait ToSimValue: ToSimValueWithType<<Self as ToSimValue>::Type> {
+    type Type: Type;
+
+    #[track_caller]
+    fn to_sim_value(&self) -> SimValue<Self::Type>;
+    #[track_caller]
+    fn into_sim_value(self) -> SimValue<Self::Type>
+    where
+        Self: Sized,
+    {
+        self.to_sim_value()
+    }
+    #[track_caller]
+    fn arc_into_sim_value(self: Arc<Self>) -> SimValue<Self::Type> {
+        self.to_sim_value()
+    }
+    #[track_caller]
+    fn arc_to_sim_value(self: &Arc<Self>) -> SimValue<Self::Type> {
+        self.to_sim_value()
+    }
+}
+
+pub trait ToSimValueWithType<T: Type> {
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: T) -> SimValue<T>;
+    #[track_caller]
+    fn into_sim_value_with_type(self, ty: T) -> SimValue<T>
+    where
+        Self: Sized,
+    {
+        self.to_sim_value_with_type(ty)
+    }
+    #[track_caller]
+    fn arc_into_sim_value_with_type(self: Arc<Self>, ty: T) -> SimValue<T> {
+        self.to_sim_value_with_type(ty)
+    }
+    #[track_caller]
+    fn arc_to_sim_value_with_type(self: &Arc<Self>, ty: T) -> SimValue<T> {
+        self.to_sim_value_with_type(ty)
+    }
+}
+
+macro_rules! forward_to_sim_value_with_type {
+    ([$($generics:tt)*] $ty:ty) => {
+        impl<$($generics)*> ToSimValueWithType<<Self as ToSimValue>::Type> for $ty {
+            fn to_sim_value_with_type(&self, ty: <Self as ToSimValue>::Type) -> SimValue<<Self as ToSimValue>::Type> {
+                let retval = Self::to_sim_value(self);
+                assert_eq!(SimValue::ty(&retval), ty);
+                retval
+            }
+            #[track_caller]
+            fn into_sim_value_with_type(self, ty: <Self as ToSimValue>::Type) -> SimValue<<Self as ToSimValue>::Type>
+            where
+                Self: Sized,
+            {
+                let retval = Self::into_sim_value(self);
+                assert_eq!(SimValue::ty(&retval), ty);
+                retval
+            }
+            #[track_caller]
+            fn arc_into_sim_value_with_type(self: Arc<Self>, ty: <Self as ToSimValue>::Type) -> SimValue<<Self as ToSimValue>::Type> {
+                let retval = Self::arc_into_sim_value(self);
+                assert_eq!(SimValue::ty(&retval), ty);
+                retval
+            }
+            #[track_caller]
+            fn arc_to_sim_value_with_type(self: &Arc<Self>, ty: <Self as ToSimValue>::Type) -> SimValue<<Self as ToSimValue>::Type> {
+                let retval = Self::arc_to_sim_value(self);
+                assert_eq!(SimValue::ty(&retval), ty);
+                retval
+            }
+        }
+    };
+}
+
+impl<T: Type> ToSimValue for SimValue<T> {
+    type Type = T;
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        self.clone()
+    }
+
+    fn into_sim_value(self) -> SimValue<Self::Type> {
+        self
+    }
+}
+
+forward_to_sim_value_with_type!([T: Type] SimValue<T>);
+
+impl<T: Type> ToSimValueWithType<T> for BitVec {
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: T) -> SimValue<T> {
+        self.clone().into_sim_value_with_type(ty)
+    }
+
+    #[track_caller]
+    fn into_sim_value_with_type(self, ty: T) -> SimValue<T> {
+        Arc::new(self).arc_into_sim_value_with_type(ty)
+    }
+
+    #[track_caller]
+    fn arc_into_sim_value_with_type(self: Arc<Self>, ty: T) -> SimValue<T> {
+        SimValue::from_bits(ty, UIntValue::new_dyn(self))
+    }
+
+    #[track_caller]
+    fn arc_to_sim_value_with_type(self: &Arc<Self>, ty: T) -> SimValue<T> {
+        SimValue::from_bits(ty, UIntValue::new_dyn(self.clone()))
+    }
+}
+
+impl<T: Type> ToSimValueWithType<T> for bitvec::boxed::BitBox {
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: T) -> SimValue<T> {
+        self.clone().into_sim_value_with_type(ty)
+    }
+
+    #[track_caller]
+    fn into_sim_value_with_type(self, ty: T) -> SimValue<T> {
+        self.into_bitvec().into_sim_value_with_type(ty)
+    }
+}
+
+impl<T: Type> ToSimValueWithType<T> for BitSlice {
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: T) -> SimValue<T> {
+        self.to_bitvec().into_sim_value_with_type(ty)
+    }
+}
+
+impl<This: ?Sized + ToSimValue> ToSimValue for &'_ This {
+    type Type = This::Type;
+
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        This::to_sim_value(self)
+    }
+}
+
+impl<This: ?Sized + ToSimValueWithType<T>, T: Type> ToSimValueWithType<T> for &'_ This {
+    fn to_sim_value_with_type(&self, ty: T) -> SimValue<T> {
+        This::to_sim_value_with_type(self, ty)
+    }
+}
+
+impl<This: ?Sized + ToSimValue> ToSimValue for &'_ mut This {
+    type Type = This::Type;
+
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        This::to_sim_value(self)
+    }
+}
+
+impl<This: ?Sized + ToSimValueWithType<T>, T: Type> ToSimValueWithType<T> for &'_ mut This {
+    fn to_sim_value_with_type(&self, ty: T) -> SimValue<T> {
+        This::to_sim_value_with_type(self, ty)
+    }
+}
+
+impl<This: ?Sized + ToSimValue> ToSimValue for Arc<This> {
+    type Type = This::Type;
+
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        This::arc_to_sim_value(self)
+    }
+    fn into_sim_value(self) -> SimValue<Self::Type> {
+        This::arc_into_sim_value(self)
+    }
+}
+
+impl<This: ?Sized + ToSimValueWithType<T>, T: Type> ToSimValueWithType<T> for Arc<This> {
+    fn to_sim_value_with_type(&self, ty: T) -> SimValue<T> {
+        This::arc_to_sim_value_with_type(self, ty)
+    }
+    fn into_sim_value_with_type(self, ty: T) -> SimValue<T> {
+        This::arc_into_sim_value_with_type(self, ty)
+    }
+}
+
+impl<This: ?Sized + ToSimValue + Send + Sync + 'static> ToSimValue
+    for crate::intern::Interned<This>
+{
+    type Type = This::Type;
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        This::to_sim_value(self)
+    }
+}
+
+impl<This: ?Sized + ToSimValueWithType<T> + Send + Sync + 'static, T: Type> ToSimValueWithType<T>
+    for crate::intern::Interned<This>
+{
+    fn to_sim_value_with_type(&self, ty: T) -> SimValue<T> {
+        This::to_sim_value_with_type(self, ty)
+    }
+}
+
+impl<This: ToSimValue> ToSimValue for Box<This> {
+    type Type = This::Type;
+
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        This::to_sim_value(self)
+    }
+    fn into_sim_value(self) -> SimValue<Self::Type> {
+        This::into_sim_value(*self)
+    }
+}
+
+impl<This: ToSimValueWithType<T>, T: Type> ToSimValueWithType<T> for Box<This> {
+    fn to_sim_value_with_type(&self, ty: T) -> SimValue<T> {
+        This::to_sim_value_with_type(self, ty)
+    }
+    fn into_sim_value_with_type(self, ty: T) -> SimValue<T> {
+        This::into_sim_value_with_type(*self, ty)
+    }
+}
+
+impl<T: Type, Len: Size> SimValue<ArrayType<T, Len>> {
+    #[track_caller]
+    pub fn from_array_elements<I: IntoIterator<Item: ToSimValueWithType<T>>>(
+        ty: ArrayType<T, Len>,
+        elements: I,
+    ) -> Self {
+        let element_ty = ty.element();
+        let elements = Vec::from_iter(
+            elements
+                .into_iter()
+                .map(|element| element.into_sim_value_with_type(element_ty)),
+        );
+        assert_eq!(elements.len(), ty.len());
+        SimValue::from_value(ty, elements.try_into().ok().expect("already checked len"))
+    }
+}
+
+impl<Element: ToSimValueWithType<T>, T: Type> ToSimValueWithType<Array<T>> for [Element] {
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: Array<T>) -> SimValue<Array<T>> {
+        SimValue::from_array_elements(ty, self)
+    }
+}
+
+impl<Element: ToSimValue<Type: StaticType>> ToSimValue for [Element] {
+    type Type = Array<Element::Type>;
+
+    #[track_caller]
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        SimValue::from_array_elements(ArrayType::new_dyn(StaticType::TYPE, self.len()), self)
+    }
+}
+
+impl<Element: ToSimValueWithType<CanonicalType>> ToSimValueWithType<CanonicalType> for [Element] {
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
+        SimValue::into_canonical(SimValue::from_array_elements(
+            <Array>::from_canonical(ty),
+            self,
+        ))
+    }
+}
+
+impl<Element: ToSimValueWithType<T>, T: Type, const N: usize> ToSimValueWithType<Array<T, N>>
+    for [Element; N]
+where
+    ConstUsize<N>: KnownSize,
+{
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: Array<T, N>) -> SimValue<Array<T, N>> {
+        SimValue::from_array_elements(ty, self)
+    }
+    #[track_caller]
+    fn into_sim_value_with_type(self, ty: Array<T, N>) -> SimValue<Array<T, N>> {
+        SimValue::from_array_elements(ty, self)
+    }
+}
+
+impl<Element: ToSimValue<Type: StaticType>, const N: usize> ToSimValue for [Element; N]
+where
+    ConstUsize<N>: KnownSize,
+{
+    type Type = Array<Element::Type, N>;
+
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        SimValue::from_array_elements(StaticType::TYPE, self)
+    }
+
+    fn into_sim_value(self) -> SimValue<Self::Type> {
+        SimValue::from_array_elements(StaticType::TYPE, self)
+    }
+}
+
+impl<Element: ToSimValueWithType<T>, T: Type, const N: usize> ToSimValueWithType<Array<T>>
+    for [Element; N]
+{
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: Array<T>) -> SimValue<Array<T>> {
+        SimValue::from_array_elements(ty, self)
+    }
+    #[track_caller]
+    fn into_sim_value_with_type(self, ty: Array<T>) -> SimValue<Array<T>> {
+        SimValue::from_array_elements(ty, self)
+    }
+}
+
+impl<Element: ToSimValueWithType<CanonicalType>, const N: usize> ToSimValueWithType<CanonicalType>
+    for [Element; N]
+{
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
+        SimValue::into_canonical(SimValue::from_array_elements(
+            <Array>::from_canonical(ty),
+            self,
+        ))
+    }
+    #[track_caller]
+    fn into_sim_value_with_type(self, ty: CanonicalType) -> SimValue<CanonicalType> {
+        SimValue::into_canonical(SimValue::from_array_elements(
+            <Array>::from_canonical(ty),
+            self,
+        ))
+    }
+}
+
+impl<Element: ToSimValueWithType<T>, T: Type> ToSimValueWithType<Array<T>> for Vec<Element> {
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: Array<T>) -> SimValue<Array<T>> {
+        SimValue::from_array_elements(ty, self)
+    }
+    #[track_caller]
+    fn into_sim_value_with_type(self, ty: Array<T>) -> SimValue<Array<T>> {
+        SimValue::from_array_elements(ty, self)
+    }
+}
+
+impl<Element: ToSimValue<Type: StaticType>> ToSimValue for Vec<Element> {
+    type Type = Array<Element::Type>;
+
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        SimValue::from_array_elements(ArrayType::new_dyn(StaticType::TYPE, self.len()), self)
+    }
+
+    fn into_sim_value(self) -> SimValue<Self::Type> {
+        SimValue::from_array_elements(ArrayType::new_dyn(StaticType::TYPE, self.len()), self)
+    }
+}
+
+impl<Element: ToSimValueWithType<CanonicalType>> ToSimValueWithType<CanonicalType>
+    for Vec<Element>
+{
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
+        SimValue::into_canonical(SimValue::from_array_elements(
+            <Array>::from_canonical(ty),
+            self,
+        ))
+    }
+    #[track_caller]
+    fn into_sim_value_with_type(self, ty: CanonicalType) -> SimValue<CanonicalType> {
+        SimValue::into_canonical(SimValue::from_array_elements(
+            <Array>::from_canonical(ty),
+            self,
+        ))
+    }
+}
+
+impl<Element: ToSimValueWithType<T>, T: Type> ToSimValueWithType<Array<T>> for Box<[Element]> {
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: Array<T>) -> SimValue<Array<T>> {
+        SimValue::from_array_elements(ty, self)
+    }
+    #[track_caller]
+    fn into_sim_value_with_type(self, ty: Array<T>) -> SimValue<Array<T>> {
+        SimValue::from_array_elements(ty, self)
+    }
+}
+
+impl<Element: ToSimValue<Type: StaticType>> ToSimValue for Box<[Element]> {
+    type Type = Array<Element::Type>;
+
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        SimValue::from_array_elements(ArrayType::new_dyn(StaticType::TYPE, self.len()), self)
+    }
+
+    fn into_sim_value(self) -> SimValue<Self::Type> {
+        SimValue::from_array_elements(ArrayType::new_dyn(StaticType::TYPE, self.len()), self)
+    }
+}
+
+impl<Element: ToSimValueWithType<CanonicalType>> ToSimValueWithType<CanonicalType>
+    for Box<[Element]>
+{
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
+        SimValue::into_canonical(SimValue::from_array_elements(
+            <Array>::from_canonical(ty),
+            self,
+        ))
+    }
+    #[track_caller]
+    fn into_sim_value_with_type(self, ty: CanonicalType) -> SimValue<CanonicalType> {
+        SimValue::into_canonical(SimValue::from_array_elements(
+            <Array>::from_canonical(ty),
+            self,
+        ))
+    }
+}
+
+impl<T: Type> ToSimValue for Expr<T> {
+    type Type = T;
+    #[track_caller]
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        SimValue::from_bitslice(
+            Expr::ty(*self),
+            &crate::expr::ToLiteralBits::to_literal_bits(self)
+                .expect("must be a literal expression"),
+        )
+    }
+}
+
+forward_to_sim_value_with_type!([T: Type] Expr<T>);
+
+macro_rules! impl_to_sim_value_for_bool_like {
+    ($ty:ident) => {
+        impl ToSimValueWithType<$ty> for bool {
+            fn to_sim_value_with_type(&self, ty: $ty) -> SimValue<$ty> {
+                SimValue::from_value(ty, *self)
+            }
+        }
+    };
+}
+
+impl ToSimValue for bool {
+    type Type = Bool;
+
+    fn to_sim_value(&self) -> SimValue<Self::Type> {
+        SimValue::from_value(Bool, *self)
+    }
+}
+
+impl_to_sim_value_for_bool_like!(Bool);
+impl_to_sim_value_for_bool_like!(AsyncReset);
+impl_to_sim_value_for_bool_like!(SyncReset);
+impl_to_sim_value_for_bool_like!(Reset);
+impl_to_sim_value_for_bool_like!(Clock);
+
+impl ToSimValueWithType<CanonicalType> for bool {
+    #[track_caller]
+    fn to_sim_value_with_type(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
+        match ty {
+            CanonicalType::UInt(_)
+            | CanonicalType::SInt(_)
+            | CanonicalType::Array(_)
+            | CanonicalType::Enum(_)
+            | CanonicalType::Bundle(_)
+            | CanonicalType::PhantomConst(_) => {
+                panic!("can't create SimValue from bool: expected value of type: {ty:?}");
+            }
+            CanonicalType::Bool(_)
+            | CanonicalType::AsyncReset(_)
+            | CanonicalType::SyncReset(_)
+            | CanonicalType::Reset(_)
+            | CanonicalType::Clock(_) => {
+                SimValue::from_bits(ty, UIntValue::new(Arc::new(BitVec::repeat(*self, 1))))
+            }
+        }
+    }
+}
+
+macro_rules! impl_to_sim_value_for_primitive_int {
+    ($prim:ident) => {
+        impl ToSimValue for $prim {
+            type Type = <$prim as ToExpr>::Type;
+
+            #[track_caller]
+            fn to_sim_value(
+                &self,
+            ) -> SimValue<Self::Type> {
+                SimValue::from_value(StaticType::TYPE, (*self).into())
+            }
+        }
+
+        forward_to_sim_value_with_type!([] $prim);
+
+        impl ToSimValueWithType<<<$prim as ToExpr>::Type as IntType>::Dyn> for $prim {
+            #[track_caller]
+            fn to_sim_value_with_type(
+                &self,
+                ty: <<$prim as ToExpr>::Type as IntType>::Dyn,
+            ) -> SimValue<<<$prim as ToExpr>::Type as IntType>::Dyn> {
+                SimValue::from_value(
+                    ty,
+                    <<$prim as ToExpr>::Type as Type>::SimValue::from(*self).as_dyn_int(),
+                )
+            }
+        }
+
+        impl ToSimValueWithType<CanonicalType> for $prim {
+            #[track_caller]
+            fn to_sim_value_with_type(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
+                let ty: <<$prim as ToExpr>::Type as IntType>::Dyn = Type::from_canonical(ty);
+                SimValue::into_canonical(self.to_sim_value_with_type(ty))
+            }
+        }
+    };
+}
+
+impl_to_sim_value_for_primitive_int!(u8);
+impl_to_sim_value_for_primitive_int!(u16);
+impl_to_sim_value_for_primitive_int!(u32);
+impl_to_sim_value_for_primitive_int!(u64);
+impl_to_sim_value_for_primitive_int!(u128);
+impl_to_sim_value_for_primitive_int!(usize);
+impl_to_sim_value_for_primitive_int!(i8);
+impl_to_sim_value_for_primitive_int!(i16);
+impl_to_sim_value_for_primitive_int!(i32);
+impl_to_sim_value_for_primitive_int!(i64);
+impl_to_sim_value_for_primitive_int!(i128);
+impl_to_sim_value_for_primitive_int!(isize);
+
+macro_rules! impl_to_sim_value_for_int_value {
+    ($IntValue:ident, $Int:ident, $IntType:ident) => {
+        impl<Width: Size> ToSimValue for $IntValue<Width> {
+            type Type = $IntType<Width>;
+
+            fn to_sim_value(&self) -> SimValue<Self::Type> {
+                SimValue::from_value(self.ty(), self.clone())
+            }
+
+            fn into_sim_value(self) -> SimValue<Self::Type> {
+                SimValue::from_value(self.ty(), self)
+            }
+        }
+
+        impl<Width: Size> ToSimValueWithType<$IntType<Width>> for $IntValue<Width> {
+            fn to_sim_value_with_type(&self, ty: $IntType<Width>) -> SimValue<$IntType<Width>> {
+                SimValue::from_value(ty, self.clone())
+            }
+
+            fn into_sim_value_with_type(self, ty: $IntType<Width>) -> SimValue<$IntType<Width>> {
+                SimValue::from_value(ty, self)
+            }
+        }
+
+        impl<Width: KnownSize> ToSimValueWithType<$Int> for $IntValue<Width> {
+            fn to_sim_value_with_type(&self, ty: $Int) -> SimValue<$Int> {
+                self.bits().to_sim_value_with_type(ty)
+            }
+
+            fn into_sim_value_with_type(self, ty: $Int) -> SimValue<$Int> {
+                self.into_bits().into_sim_value_with_type(ty)
+            }
+        }
+
+        impl<Width: Size> ToSimValueWithType<CanonicalType> for $IntValue<Width> {
+            #[track_caller]
+            fn to_sim_value_with_type(&self, ty: CanonicalType) -> SimValue<CanonicalType> {
+                SimValue::into_canonical(
+                    self.to_sim_value_with_type($IntType::<Width>::from_canonical(ty)),
+                )
+            }
+
+            #[track_caller]
+            fn into_sim_value_with_type(self, ty: CanonicalType) -> SimValue<CanonicalType> {
+                SimValue::into_canonical(
+                    self.into_sim_value_with_type($IntType::<Width>::from_canonical(ty)),
+                )
+            }
+        }
+    };
+}
+
+impl_to_sim_value_for_int_value!(UIntValue, UInt, UIntType);
+impl_to_sim_value_for_int_value!(SIntValue, SInt, SIntType);

crates/fayalite/src/sim/vcd.rs

@@ -14,9 +14,10 @@ use crate::{
         TraceModuleIO, TraceReg, TraceSInt, TraceScalar, TraceScalarId, TraceScope, TraceSyncReset,
         TraceUInt, TraceWire, TraceWriter, TraceWriterDecls,
     },
+    util::HashMap,
 };
 use bitvec::{order::Lsb0, slice::BitSlice};
-use hashbrown::{hash_map::Entry, HashMap};
+use hashbrown::hash_map::Entry;
 use std::{
     fmt::{self, Write as _},
     io, mem,

crates/fayalite/src/source_location.rs

@@ -2,9 +2,8 @@
 // See Notices.txt for copyright information
 use crate::{
     intern::{Intern, Interned},
-    util::DebugAsDisplay,
+    util::{DebugAsDisplay, HashMap},
 };
-use hashbrown::HashMap;
 use std::{cell::RefCell, fmt, num::NonZeroUsize, panic, path::Path};
 
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -97,7 +96,7 @@ impl NormalizeFilesForTestsState {
     fn new() -> Self {
         Self {
             test_position: panic::Location::caller(),
-            file_pattern_matches: HashMap::new(),
+            file_pattern_matches: HashMap::default(),
         }
     }
 }
@@ -143,7 +142,7 @@ impl From<&'_ panic::Location<'_>> for SourceLocation {
                         map.entry_ref(file)
                             .or_insert_with(|| NormalizedFileForTestState {
                                 file_name_id: NonZeroUsize::new(len + 1).unwrap(),
-                                positions_map: HashMap::new(),
+                                positions_map: HashMap::default(),
                             });
                     file_str = m.generate_file_name(file_state.file_name_id);
                     file = &file_str;

crates/fayalite/src/testing.rs

@@ -3,9 +3,9 @@
 use crate::{
     cli::{FormalArgs, FormalMode, FormalOutput, RunPhase},
     firrtl::ExportOptions,
+    util::HashMap,
 };
 use clap::Parser;
-use hashbrown::HashMap;
 use serde::Deserialize;
 use std::{
     fmt::Write,
@@ -87,7 +87,7 @@ fn get_assert_formal_target_path(test_name: &dyn std::fmt::Display) -> PathBuf {
     let index = *DIRS
         .lock()
         .unwrap()
-        .get_or_insert_with(HashMap::new)
+        .get_or_insert_with(HashMap::default)
         .entry_ref(&dir)
         .and_modify(|v| *v += 1)
         .or_insert(0);

crates/fayalite/src/ty.rs

@@ -7,12 +7,19 @@ use crate::{
     clock::Clock,
     enum_::Enum,
     expr::Expr,
-    int::{Bool, SInt, UInt},
+    int::{Bool, SInt, UInt, UIntValue},
     intern::{Intern, Interned},
+    phantom_const::PhantomConst,
     reset::{AsyncReset, Reset, SyncReset},
+    sim::value::{SimValue, ToSimValueWithType},
     source_location::SourceLocation,
+    util::ConstUsize,
 };
-use std::{fmt, hash::Hash, iter::FusedIterator, ops::Index};
+use bitvec::slice::BitSlice;
+use serde::{de::DeserializeOwned, Deserialize, Deserializer, Serialize, Serializer};
+use std::{fmt, hash::Hash, iter::FusedIterator, ops::Index, sync::Arc};
+
+pub(crate) mod serde_impls;
 
 #[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
 #[non_exhaustive]
@@ -35,6 +42,7 @@ pub enum CanonicalType {
     SyncReset(SyncReset),
     Reset(Reset),
     Clock(Clock),
+    PhantomConst(PhantomConst),
 }
 
 impl fmt::Debug for CanonicalType {
@@ -50,10 +58,29 @@ impl fmt::Debug for CanonicalType {
             Self::SyncReset(v) => v.fmt(f),
             Self::Reset(v) => v.fmt(f),
             Self::Clock(v) => v.fmt(f),
+            Self::PhantomConst(v) => v.fmt(f),
         }
     }
 }
 
+impl Serialize for CanonicalType {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serde_impls::SerdeCanonicalType::from(*self).serialize(serializer)
+    }
+}
+
+impl<'de> Deserialize<'de> for CanonicalType {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        Ok(serde_impls::SerdeCanonicalType::deserialize(deserializer)?.into())
+    }
+}
+
 impl CanonicalType {
     pub fn type_properties(self) -> TypeProperties {
         match self {
@@ -67,6 +94,7 @@ impl CanonicalType {
             CanonicalType::SyncReset(v) => v.type_properties(),
             CanonicalType::Reset(v) => v.type_properties(),
             CanonicalType::Clock(v) => v.type_properties(),
+            CanonicalType::PhantomConst(v) => v.type_properties(),
         }
     }
     pub fn is_passive(self) -> bool {
@@ -143,9 +171,18 @@ impl CanonicalType {
                 };
                 lhs.can_connect(rhs)
             }
+            CanonicalType::PhantomConst(lhs) => {
+                let CanonicalType::PhantomConst(rhs) = rhs else {
+                    return false;
+                };
+                lhs.can_connect(rhs)
             }
         }
     }
+    pub(crate) fn as_serde_unexpected_str(self) -> &'static str {
+        serde_impls::SerdeCanonicalType::from(self).as_serde_unexpected_str()
+    }
+}
 
 pub trait MatchVariantAndInactiveScope: Sized {
     type MatchVariant: 'static + Send + Sync;
@@ -166,7 +203,7 @@ impl<T: 'static + Send + Sync> MatchVariantAndInactiveScope for MatchVariantWith
 }
 
 pub trait FillInDefaultedGenerics {
-    type Type: Type;
+    type Type;
     fn fill_in_defaulted_generics(self) -> Self::Type;
 }
 
@@ -178,6 +215,22 @@ impl<T: Type> FillInDefaultedGenerics for T {
     }
 }
 
+impl FillInDefaultedGenerics for usize {
+    type Type = usize;
+
+    fn fill_in_defaulted_generics(self) -> Self::Type {
+        self
+    }
+}
+
+impl<const V: usize> FillInDefaultedGenerics for ConstUsize<V> {
+    type Type = ConstUsize<V>;
+
+    fn fill_in_defaulted_generics(self) -> Self::Type {
+        self
+    }
+}
+
 mod sealed {
     pub trait TypeOrDefaultSealed {}
     pub trait BaseTypeSealed {}
@@ -195,6 +248,34 @@ macro_rules! impl_base_type {
     };
 }
 
+macro_rules! impl_base_type_serde {
+    ($name:ident, $expected:literal) => {
+        impl Serialize for $name {
+            fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+            where
+                S: Serializer,
+            {
+                self.canonical().serialize(serializer)
+            }
+        }
+
+        impl<'de> Deserialize<'de> for $name {
+            fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+            where
+                D: Deserializer<'de>,
+            {
+                match CanonicalType::deserialize(deserializer)? {
+                    CanonicalType::$name(retval) => Ok(retval),
+                    ty => Err(serde::de::Error::invalid_value(
+                        serde::de::Unexpected::Other(ty.as_serde_unexpected_str()),
+                        &$expected,
+                    )),
+                }
+            }
+        }
+    };
+}
+
 impl_base_type!(UInt);
 impl_base_type!(SInt);
 impl_base_type!(Bool);
@@ -205,6 +286,15 @@ impl_base_type!(AsyncReset);
 impl_base_type!(SyncReset);
 impl_base_type!(Reset);
 impl_base_type!(Clock);
+impl_base_type!(PhantomConst);
+
+impl_base_type_serde!(Bool, "a Bool");
+impl_base_type_serde!(Enum, "an Enum");
+impl_base_type_serde!(Bundle, "a Bundle");
+impl_base_type_serde!(AsyncReset, "an AsyncReset");
+impl_base_type_serde!(SyncReset, "a SyncReset");
+impl_base_type_serde!(Reset, "a Reset");
+impl_base_type_serde!(Clock, "a Clock");
 
 impl sealed::BaseTypeSealed for CanonicalType {}
 
@@ -240,6 +330,7 @@ pub trait Type:
 {
     type BaseType: BaseType;
     type MaskType: Type<MaskType = Self::MaskType>;
+    type SimValue: fmt::Debug + Clone + 'static + ToSimValueWithType<Self>;
     type MatchVariant: 'static + Send + Sync;
     type MatchActiveScope;
     type MatchVariantAndInactiveScope: MatchVariantAndInactiveScope<
@@ -257,9 +348,22 @@ pub trait Type:
     fn canonical(&self) -> CanonicalType;
     fn from_canonical(canonical_type: CanonicalType) -> Self;
     fn source_location() -> SourceLocation;
+    fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue;
+    fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice);
+    fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice);
 }
 
-pub trait BaseType: Type<BaseType = Self> + sealed::BaseTypeSealed + Into<CanonicalType> {}
+pub trait BaseType:
+    Type<
+        BaseType = Self,
+        MaskType: Serialize + DeserializeOwned,
+        SimValue: Serialize + DeserializeOwned,
+    > + sealed::BaseTypeSealed
+    + Into<CanonicalType>
+    + Serialize
+    + DeserializeOwned
+{
+}
 
 macro_rules! impl_match_variant_as_self {
     () => {
@@ -286,6 +390,7 @@ pub trait TypeWithDeref: Type {
 impl Type for CanonicalType {
     type BaseType = CanonicalType;
     type MaskType = CanonicalType;
+    type SimValue = OpaqueSimValue;
     impl_match_variant_as_self!();
     fn mask_type(&self) -> Self::MaskType {
         match self {
@@ -299,6 +404,7 @@ impl Type for CanonicalType {
             CanonicalType::SyncReset(v) => v.mask_type().canonical(),
             CanonicalType::Reset(v) => v.mask_type().canonical(),
             CanonicalType::Clock(v) => v.mask_type().canonical(),
+            CanonicalType::PhantomConst(v) => v.mask_type().canonical(),
         }
     }
     fn canonical(&self) -> CanonicalType {
@@ -310,9 +416,60 @@ impl Type for CanonicalType {
     fn source_location() -> SourceLocation {
         SourceLocation::builtin()
     }
+    fn sim_value_from_bits(&self, bits: &BitSlice) -> Self::SimValue {
+        assert_eq!(bits.len(), self.bit_width());
+        OpaqueSimValue::from_bitslice(bits)
+    }
+    fn sim_value_clone_from_bits(&self, value: &mut Self::SimValue, bits: &BitSlice) {
+        assert_eq!(bits.len(), self.bit_width());
+        assert_eq!(value.bit_width(), self.bit_width());
+        value.bits_mut().bits_mut().copy_from_bitslice(bits);
+    }
+    fn sim_value_to_bits(&self, value: &Self::SimValue, bits: &mut BitSlice) {
+        assert_eq!(bits.len(), self.bit_width());
+        assert_eq!(value.bit_width(), self.bit_width());
+        bits.copy_from_bitslice(value.bits().bits());
+    }
 }
 
-pub trait StaticType: Type {
+#[derive(Clone, PartialEq, Eq, Hash, Debug, Serialize, Deserialize)]
+pub struct OpaqueSimValue {
+    bits: UIntValue,
+}
+
+impl OpaqueSimValue {
+    pub fn bit_width(&self) -> usize {
+        self.bits.width()
+    }
+    pub fn bits(&self) -> &UIntValue {
+        &self.bits
+    }
+    pub fn bits_mut(&mut self) -> &mut UIntValue {
+        &mut self.bits
+    }
+    pub fn into_bits(self) -> UIntValue {
+        self.bits
+    }
+    pub fn from_bits(bits: UIntValue) -> Self {
+        Self { bits }
+    }
+    pub fn from_bitslice(v: &BitSlice) -> Self {
+        Self {
+            bits: UIntValue::new(Arc::new(v.to_bitvec())),
+        }
+    }
+}
+
+impl<T: Type<SimValue = OpaqueSimValue>> ToSimValueWithType<T> for OpaqueSimValue {
+    fn to_sim_value_with_type(&self, ty: T) -> SimValue<T> {
+        SimValue::from_value(ty, self.clone())
+    }
+    fn into_sim_value_with_type(self, ty: T) -> SimValue<T> {
+        SimValue::from_value(ty, self)
+    }
+}
+
+pub trait StaticType: Type + Default {
     const TYPE: Self;
     const MASK_TYPE: Self::MaskType;
     const TYPE_PROPERTIES: TypeProperties;

crates/fayalite/src/ty/serde_impls.rs

@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+use crate::{
+    array::Array,
+    bundle::{Bundle, BundleType},
+    clock::Clock,
+    enum_::{Enum, EnumType},
+    int::{Bool, SInt, UInt},
+    intern::Interned,
+    phantom_const::{PhantomConstCanonicalValue, PhantomConstValue},
+    prelude::PhantomConst,
+    reset::{AsyncReset, Reset, SyncReset},
+    ty::{BaseType, CanonicalType},
+};
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+pub(crate) struct SerdePhantomConst<T>(pub T);
+
+impl<T: ?Sized + PhantomConstValue> Serialize for SerdePhantomConst<Interned<T>> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        self.0.serialize(serializer)
+    }
+}
+
+impl<'de, T: ?Sized + PhantomConstValue> Deserialize<'de> for SerdePhantomConst<Interned<T>> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        T::deserialize_value(deserializer).map(Self)
+    }
+}
+
+#[derive(Serialize, Deserialize)]
+#[serde(rename = "CanonicalType")]
+pub(crate) enum SerdeCanonicalType<
+    ArrayElement = CanonicalType,
+    ThePhantomConst = SerdePhantomConst<Interned<PhantomConstCanonicalValue>>,
+> {
+    UInt {
+        width: usize,
+    },
+    SInt {
+        width: usize,
+    },
+    Bool,
+    Array {
+        element: ArrayElement,
+        len: usize,
+    },
+    Enum {
+        variants: Interned<[crate::enum_::EnumVariant]>,
+    },
+    Bundle {
+        fields: Interned<[crate::bundle::BundleField]>,
+    },
+    AsyncReset,
+    SyncReset,
+    Reset,
+    Clock,
+    PhantomConst(ThePhantomConst),
+}
+
+impl<ArrayElement, PhantomConstInner> SerdeCanonicalType<ArrayElement, PhantomConstInner> {
+    pub(crate) fn as_serde_unexpected_str(&self) -> &'static str {
+        match self {
+            Self::UInt { .. } => "a UInt",
+            Self::SInt { .. } => "a SInt",
+            Self::Bool => "a Bool",
+            Self::Array { .. } => "an Array",
+            Self::Enum { .. } => "an Enum",
+            Self::Bundle { .. } => "a Bundle",
+            Self::AsyncReset => "an AsyncReset",
+            Self::SyncReset => "a SyncReset",
+            Self::Reset => "a Reset",
+            Self::Clock => "a Clock",
+            Self::PhantomConst(_) => "a PhantomConst",
+        }
+    }
+}
+
+impl<T: BaseType> From<T> for SerdeCanonicalType {
+    fn from(ty: T) -> Self {
+        let ty: CanonicalType = ty.into();
+        match ty {
+            CanonicalType::UInt(ty) => Self::UInt { width: ty.width() },
+            CanonicalType::SInt(ty) => Self::SInt { width: ty.width() },
+            CanonicalType::Bool(Bool {}) => Self::Bool,
+            CanonicalType::Array(ty) => Self::Array {
+                element: ty.element(),
+                len: ty.len(),
+            },
+            CanonicalType::Enum(ty) => Self::Enum {
+                variants: ty.variants(),
+            },
+            CanonicalType::Bundle(ty) => Self::Bundle {
+                fields: ty.fields(),
+            },
+            CanonicalType::AsyncReset(AsyncReset {}) => Self::AsyncReset,
+            CanonicalType::SyncReset(SyncReset {}) => Self::SyncReset,
+            CanonicalType::Reset(Reset {}) => Self::Reset,
+            CanonicalType::Clock(Clock {}) => Self::Clock,
+            CanonicalType::PhantomConst(ty) => Self::PhantomConst(SerdePhantomConst(ty.get())),
+        }
+    }
+}
+
+impl From<SerdeCanonicalType> for CanonicalType {
+    fn from(ty: SerdeCanonicalType) -> Self {
+        match ty {
+            SerdeCanonicalType::UInt { width } => Self::UInt(UInt::new(width)),
+            SerdeCanonicalType::SInt { width } => Self::SInt(SInt::new(width)),
+            SerdeCanonicalType::Bool => Self::Bool(Bool),
+            SerdeCanonicalType::Array { element, len } => Self::Array(Array::new(element, len)),
+            SerdeCanonicalType::Enum { variants } => Self::Enum(Enum::new(variants)),
+            SerdeCanonicalType::Bundle { fields } => Self::Bundle(Bundle::new(fields)),
+            SerdeCanonicalType::AsyncReset => Self::AsyncReset(AsyncReset),
+            SerdeCanonicalType::SyncReset => Self::SyncReset(SyncReset),
+            SerdeCanonicalType::Reset => Self::Reset(Reset),
+            SerdeCanonicalType::Clock => Self::Clock(Clock),
+            SerdeCanonicalType::PhantomConst(value) => {
+                Self::PhantomConst(PhantomConst::new(value.0))
+            }
+        }
+    }
+}

crates/fayalite/src/util.rs

@@ -1,12 +1,23 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 // See Notices.txt for copyright information
 
+pub(crate) mod alternating_cell;
 mod const_bool;
 mod const_cmp;
 mod const_usize;
 mod misc;
 mod scoped_ref;
 pub(crate) mod streaming_read_utf8;
+mod test_hasher;
+
+// allow easily switching the hasher crate-wide for testing
+#[cfg(feature = "unstable-test-hasher")]
+pub type DefaultBuildHasher = test_hasher::DefaultBuildHasher;
+#[cfg(not(feature = "unstable-test-hasher"))]
+pub(crate) type DefaultBuildHasher = hashbrown::DefaultHashBuilder;
+
+pub(crate) type HashMap<K, V> = hashbrown::HashMap<K, V, DefaultBuildHasher>;
+pub(crate) type HashSet<T> = hashbrown::HashSet<T, DefaultBuildHasher>;
 
 #[doc(inline)]
 pub use const_bool::{ConstBool, ConstBoolDispatch, ConstBoolDispatchTag, GenericConstBool};
@@ -29,4 +40,5 @@ pub use misc::{
 };
 
 pub mod job_server;
+pub mod prefix_sum;
 pub mod ready_valid;

crates/fayalite/src/util/alternating_cell.rs

@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+use crate::util::DebugAsDisplay;
+use std::{
+    cell::{Cell, UnsafeCell},
+    fmt,
+};
+
+pub(crate) trait AlternatingCellMethods {
+    fn unique_to_shared(&mut self);
+    fn shared_to_unique(&mut self);
+}
+
+#[derive(Copy, Clone, Debug)]
+enum State {
+    Unique,
+    Shared,
+    Locked,
+}
+
+pub(crate) struct AlternatingCell<T: ?Sized> {
+    state: Cell<State>,
+    value: UnsafeCell<T>,
+}
+
+impl<T: ?Sized + fmt::Debug + AlternatingCellMethods> fmt::Debug for AlternatingCell<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("AlternatingCell")
+            .field(
+                self.try_share()
+                    .as_ref()
+                    .map(|v| -> &dyn fmt::Debug { v })
+                    .unwrap_or(&DebugAsDisplay("<...>")),
+            )
+            .finish()
+    }
+}
+
+impl<T: ?Sized> AlternatingCell<T> {
+    pub(crate) const fn new_shared(value: T) -> Self
+    where
+        T: Sized,
+    {
+        Self {
+            state: Cell::new(State::Shared),
+            value: UnsafeCell::new(value),
+        }
+    }
+    pub(crate) const fn new_unique(value: T) -> Self
+    where
+        T: Sized,
+    {
+        Self {
+            state: Cell::new(State::Unique),
+            value: UnsafeCell::new(value),
+        }
+    }
+    pub(crate) fn is_unique(&self) -> bool {
+        matches!(self.state.get(), State::Unique)
+    }
+    pub(crate) fn is_shared(&self) -> bool {
+        matches!(self.state.get(), State::Shared)
+    }
+    pub(crate) fn into_inner(self) -> T
+    where
+        T: Sized,
+    {
+        self.value.into_inner()
+    }
+    pub(crate) fn try_share(&self) -> Option<&T>
+    where
+        T: AlternatingCellMethods,
+    {
+        match self.state.get() {
+            State::Shared => {}
+            State::Unique => {
+                struct Locked<'a>(&'a Cell<State>);
+                impl Drop for Locked<'_> {
+                    fn drop(&mut self) {
+                        self.0.set(State::Shared);
+                    }
+                }
+                self.state.set(State::Locked);
+                let lock = Locked(&self.state);
+                // Safety: state is Locked, so nothing else will
+                // access value while calling unique_to_shared.
+                unsafe { &mut *self.value.get() }.unique_to_shared();
+                drop(lock);
+            }
+            State::Locked => return None,
+        }
+
+        // Safety: state is Shared so nothing will create any mutable
+        // references until the returned reference's lifetime expires.
+        Some(unsafe { &*self.value.get() })
+    }
+    #[track_caller]
+    pub(crate) fn share(&self) -> &T
+    where
+        T: AlternatingCellMethods,
+    {
+        let Some(retval) = self.try_share() else {
+            panic!("`share` called recursively");
+        };
+        retval
+    }
+    pub(crate) fn unique(&mut self) -> &mut T
+    where
+        T: AlternatingCellMethods,
+    {
+        match self.state.get() {
+            State::Shared => {
+                self.state.set(State::Unique);
+                self.value.get_mut().shared_to_unique();
+            }
+            State::Unique => {}
+            State::Locked => unreachable!(),
+        }
+        self.value.get_mut()
+    }
+}

crates/fayalite/src/util/const_bool.rs

@@ -1,5 +1,9 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 // See Notices.txt for copyright information
+use serde::{
+    de::{DeserializeOwned, Error, Unexpected},
+    Deserialize, Deserializer, Serialize, Serializer,
+};
 use std::{fmt::Debug, hash::Hash, mem::ManuallyDrop, ptr};
 
 mod sealed {
@@ -9,7 +13,17 @@ mod sealed {
 /// # Safety
 /// the only implementation is `ConstBool<Self::VALUE>`
 pub unsafe trait GenericConstBool:
-    sealed::Sealed + Copy + Ord + Hash + Default + Debug + 'static + Send + Sync
+    sealed::Sealed
+    + Copy
+    + Ord
+    + Hash
+    + Default
+    + Debug
+    + 'static
+    + Send
+    + Sync
+    + Serialize
+    + DeserializeOwned
 {
     const VALUE: bool;
 }
@@ -30,6 +44,32 @@ unsafe impl<const VALUE: bool> GenericConstBool for ConstBool<VALUE> {
     const VALUE: bool = VALUE;
 }
 
+impl<const VALUE: bool> Serialize for ConstBool<VALUE> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        VALUE.serialize(serializer)
+    }
+}
+
+impl<'de, const VALUE: bool> Deserialize<'de> for ConstBool<VALUE> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let value = bool::deserialize(deserializer)?;
+        if value == VALUE {
+            Ok(ConstBool)
+        } else {
+            Err(D::Error::invalid_value(
+                Unexpected::Bool(value),
+                &if VALUE { "true" } else { "false" },
+            ))
+        }
+    }
+}
+
 pub trait ConstBoolDispatchTag {
     type Type<Select: GenericConstBool>;
 }

crates/fayalite/src/util/const_usize.rs

@@ -1,5 +1,9 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 // See Notices.txt for copyright information
+use serde::{
+    de::{DeserializeOwned, Error, Unexpected},
+    Deserialize, Deserializer, Serialize, Serializer,
+};
 use std::{fmt::Debug, hash::Hash};
 
 mod sealed {
@@ -8,7 +12,17 @@ mod sealed {
 
 /// the only implementation is `ConstUsize<Self::VALUE>`
 pub trait GenericConstUsize:
-    sealed::Sealed + Copy + Ord + Hash + Default + Debug + 'static + Send + Sync
+    sealed::Sealed
+    + Copy
+    + Ord
+    + Hash
+    + Default
+    + Debug
+    + 'static
+    + Send
+    + Sync
+    + Serialize
+    + DeserializeOwned
 {
     const VALUE: usize;
 }
@@ -27,3 +41,29 @@ impl<const VALUE: usize> sealed::Sealed for ConstUsize<VALUE> {}
 impl<const VALUE: usize> GenericConstUsize for ConstUsize<VALUE> {
     const VALUE: usize = VALUE;
 }
+
+impl<const VALUE: usize> Serialize for ConstUsize<VALUE> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        VALUE.serialize(serializer)
+    }
+}
+
+impl<'de, const VALUE: usize> Deserialize<'de> for ConstUsize<VALUE> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let value = usize::deserialize(deserializer)?;
+        if value == VALUE {
+            Ok(ConstUsize)
+        } else {
+            Err(D::Error::invalid_value(
+                Unexpected::Unsigned(value as u64),
+                &&*VALUE.to_string(),
+            ))
+        }
+    }
+}

crates/fayalite/src/util/prefix_sum.rs

@@ -0,0 +1,839 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+// code derived from:
+// https://web.archive.org/web/20250303054010/https://git.libre-soc.org/?p=nmutil.git;a=blob;f=src/nmutil/prefix_sum.py;hb=effeb28e5848392adddcdad1f6e7a098f2a44c9c
+
+use crate::intern::{Intern, Interned, Memoize};
+use std::{borrow::Cow, num::NonZeroUsize};
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+pub struct PrefixSumOp {
+    pub lhs_index: usize,
+    pub rhs_and_dest_index: NonZeroUsize,
+    pub row: u32,
+}
+
+#[derive(Clone, PartialEq, Eq, Hash, Debug)]
+#[non_exhaustive]
+pub struct DiagramConfig {
+    pub space: Cow<'static, str>,
+    pub vertical_bar: Cow<'static, str>,
+    pub plus: Cow<'static, str>,
+    pub slant: Cow<'static, str>,
+    pub connect: Cow<'static, str>,
+    pub no_connect: Cow<'static, str>,
+    pub padding: usize,
+}
+
+impl DiagramConfig {
+    pub const fn new() -> Self {
+        Self {
+            space: Cow::Borrowed(" "),
+            vertical_bar: Cow::Borrowed("|"),
+            plus: Cow::Borrowed("\u{2295}"), // ⊕
+            slant: Cow::Borrowed(r"\"),
+            connect: Cow::Borrowed("\u{25CF}"), // ●
+            no_connect: Cow::Borrowed("X"),
+            padding: 1,
+        }
+    }
+    pub fn draw(self, ops: impl IntoIterator<Item = PrefixSumOp>, item_count: usize) -> String {
+        #[derive(Copy, Clone, Debug)]
+        struct DiagramCell {
+            slant: bool,
+            plus: bool,
+            tee: bool,
+        }
+        let mut ops_by_row: Vec<Vec<PrefixSumOp>> = Vec::new();
+        let mut last_row = 0;
+        ops.into_iter().for_each(|op| {
+            assert!(
+                op.lhs_index < op.rhs_and_dest_index.get(),
+                "invalid PrefixSumOp! lhs_index must be less \
+                than rhs_and_dest_index: {op:?}",
+            );
+            assert!(
+                op.row >= last_row,
+                "invalid PrefixSumOp! row must \
+                not decrease (row last was: {last_row}): {op:?}",
+            );
+            let ops = if op.row > last_row || ops_by_row.is_empty() {
+                ops_by_row.push(vec![]);
+                ops_by_row.last_mut().expect("just pushed")
+            } else {
+                ops_by_row
+                    .last_mut()
+                    .expect("just checked if ops_by_row is empty")
+            };
+            if let Some(last) = ops.last() {
+                assert!(
+                    op.rhs_and_dest_index < last.rhs_and_dest_index,
+                    "invalid PrefixSumOp! rhs_and_dest_index must strictly \
+                    decrease in a row:\nthis op: {op:?}\nlast op: {last:?}",
+                );
+            }
+            ops.push(op);
+            last_row = op.row;
+        });
+        let blank_row = || {
+            vec![
+                DiagramCell {
+                    slant: false,
+                    plus: false,
+                    tee: false
+                };
+                item_count
+            ]
+        };
+        let mut cells = vec![blank_row()];
+        for ops in ops_by_row {
+            let max_distance = ops
+                .iter()
+                .map(
+                    |&PrefixSumOp {
+                         lhs_index,
+                         rhs_and_dest_index,
+                         ..
+                     }| { rhs_and_dest_index.get() - lhs_index },
+                )
+                .max()
+                .expect("ops is known to be non-empty");
+            cells.extend((0..max_distance).map(|_| blank_row()));
+            for op in ops {
+                let mut y = cells.len() - 1;
+                assert!(
+                    op.rhs_and_dest_index.get() < item_count,
+                    "invalid PrefixSumOp! rhs_and_dest_index must be \
+                    less than item_count ({item_count}): {op:?}",
+                );
+                let mut x = op.rhs_and_dest_index.get();
+                cells[y][x].plus = true;
+                x -= 1;
+                y -= 1;
+                while op.lhs_index < x {
+                    cells[y][x].slant = true;
+                    x -= 1;
+                    y -= 1;
+                }
+                cells[y][x].tee = true;
+            }
+        }
+        let mut retval = String::new();
+        let mut row_text = vec![String::new(); 2 * self.padding + 1];
+        for cells_row in cells {
+            for cell in cells_row {
+                // top padding
+                for y in 0..self.padding {
+                    // top left padding
+                    for x in 0..self.padding {
+                        row_text[y] += if x == y && (cell.plus || cell.slant) {
+                            &self.slant
+                        } else {
+                            &self.space
+                        };
+                    }
+                    // top vertical bar
+                    row_text[y] += &self.vertical_bar;
+                    // top right padding
+                    for _ in 0..self.padding {
+                        row_text[y] += &self.space;
+                    }
+                }
+                // center left padding
+                for _ in 0..self.padding {
+                    row_text[self.padding] += &self.space;
+                }
+                // center
+                row_text[self.padding] += if cell.plus {
+                    &self.plus
+                } else if cell.tee {
+                    &self.connect
+                } else if cell.slant {
+                    &self.no_connect
+                } else {
+                    &self.vertical_bar
+                };
+                // center right padding
+                for _ in 0..self.padding {
+                    row_text[self.padding] += &self.space;
+                }
+                let bottom_padding_start = self.padding + 1;
+                let bottom_padding_last = self.padding * 2;
+                // bottom padding
+                for y in bottom_padding_start..=bottom_padding_last {
+                    // bottom left padding
+                    for _ in 0..self.padding {
+                        row_text[y] += &self.space;
+                    }
+                    // bottom vertical bar
+                    row_text[y] += &self.vertical_bar;
+                    // bottom right padding
+                    for x in bottom_padding_start..=bottom_padding_last {
+                        row_text[y] += if x == y && (cell.tee || cell.slant) {
+                            &self.slant
+                        } else {
+                            &self.space
+                        };
+                    }
+                }
+            }
+            for line in &mut row_text {
+                retval += line.trim_end();
+                retval += "\n";
+                line.clear();
+            }
+        }
+        retval
+    }
+}
+
+impl Default for DiagramConfig {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl PrefixSumOp {
+    pub fn diagram(ops: impl IntoIterator<Item = Self>, item_count: usize) -> String {
+        Self::diagram_with_config(ops, item_count, DiagramConfig::new())
+    }
+    pub fn diagram_with_config(
+        ops: impl IntoIterator<Item = Self>,
+        item_count: usize,
+        config: DiagramConfig,
+    ) -> String {
+        config.draw(ops, item_count)
+    }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+pub enum PrefixSumAlgorithm {
+    /// Uses the algorithm from:
+    /// <https://en.wikipedia.org/wiki/Prefix_sum#Algorithm_1:_Shorter_span,_more_parallel>
+    LowLatency,
+    /// Uses the algorithm from:
+    /// <https://en.wikipedia.org/wiki/Prefix_sum#Algorithm_2:_Work-efficient>
+    WorkEfficient,
+}
+
+impl PrefixSumAlgorithm {
+    fn ops_impl(self, item_count: usize) -> Vec<PrefixSumOp> {
+        let mut retval = Vec::new();
+        let mut distance = 1;
+        let mut row = 0;
+        while distance < item_count {
+            let double_distance = distance
+                .checked_mul(2)
+                .expect("prefix-sum item_count is too big");
+            let (start, step) = match self {
+                Self::LowLatency => (distance, 1),
+                Self::WorkEfficient => (double_distance - 1, double_distance),
+            };
+            for rhs_and_dest_index in (start..item_count).step_by(step).rev() {
+                let Some(rhs_and_dest_index) = NonZeroUsize::new(rhs_and_dest_index) else {
+                    unreachable!();
+                };
+                let lhs_index = rhs_and_dest_index.get() - distance;
+                retval.push(PrefixSumOp {
+                    lhs_index,
+                    rhs_and_dest_index,
+                    row,
+                });
+            }
+            distance = double_distance;
+            row += 1;
+        }
+        match self {
+            Self::LowLatency => {}
+            Self::WorkEfficient => {
+                distance /= 2;
+                while distance >= 1 {
+                    let start = distance
+                        .checked_mul(3)
+                        .expect("prefix-sum item_count is too big")
+                        - 1;
+                    for rhs_and_dest_index in (start..item_count).step_by(distance * 2).rev() {
+                        let Some(rhs_and_dest_index) = NonZeroUsize::new(rhs_and_dest_index) else {
+                            unreachable!();
+                        };
+                        let lhs_index = rhs_and_dest_index.get() - distance;
+                        retval.push(PrefixSumOp {
+                            lhs_index,
+                            rhs_and_dest_index,
+                            row,
+                        });
+                    }
+                    row += 1;
+                    distance /= 2;
+                }
+            }
+        }
+        retval
+    }
+    pub fn ops(self, item_count: usize) -> Interned<[PrefixSumOp]> {
+        #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+        struct MyMemoize(PrefixSumAlgorithm);
+        impl Memoize for MyMemoize {
+            type Input = usize;
+            type InputOwned = usize;
+            type Output = Interned<[PrefixSumOp]>;
+
+            fn inner(self, item_count: &Self::Input) -> Self::Output {
+                Intern::intern_owned(self.0.ops_impl(*item_count))
+            }
+        }
+        MyMemoize(self).get_owned(item_count)
+    }
+    pub fn run<T>(self, items: impl IntoIterator<Item = T>, f: impl FnMut(&T, &T) -> T) -> Vec<T> {
+        let mut items = Vec::from_iter(items);
+        self.run_on_slice(&mut items, f);
+        items
+    }
+    pub fn run_on_slice<T>(self, items: &mut [T], mut f: impl FnMut(&T, &T) -> T) -> &mut [T] {
+        self.ops(items.len()).into_iter().for_each(
+            |PrefixSumOp {
+                 lhs_index,
+                 rhs_and_dest_index,
+                 row: _,
+             }| {
+                items[rhs_and_dest_index.get()] =
+                    f(&items[lhs_index], &items[rhs_and_dest_index.get()]);
+            },
+        );
+        items
+    }
+    pub fn filtered_ops(
+        self,
+        item_live_out_flags: impl IntoIterator<Item = bool>,
+    ) -> Vec<PrefixSumOp> {
+        let mut item_live_out_flags = Vec::from_iter(item_live_out_flags);
+        let prefix_sum_ops = self.ops(item_live_out_flags.len());
+        let mut ops_live_flags = vec![false; prefix_sum_ops.len()];
+        for (
+            op_index,
+            &PrefixSumOp {
+                lhs_index,
+                rhs_and_dest_index,
+                row: _,
+            },
+        ) in prefix_sum_ops.iter().enumerate().rev()
+        {
+            let live = item_live_out_flags[rhs_and_dest_index.get()];
+            item_live_out_flags[lhs_index] |= live;
+            ops_live_flags[op_index] = live;
+        }
+        prefix_sum_ops
+            .into_iter()
+            .zip(ops_live_flags)
+            .filter_map(|(op, live)| live.then_some(op))
+            .collect()
+    }
+    pub fn reduce_ops(self, item_count: usize) -> Interned<[PrefixSumOp]> {
+        #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+        struct MyMemoize(PrefixSumAlgorithm);
+        impl Memoize for MyMemoize {
+            type Input = usize;
+            type InputOwned = usize;
+            type Output = Interned<[PrefixSumOp]>;
+
+            fn inner(self, item_count: &Self::Input) -> Self::Output {
+                let mut item_live_out_flags = vec![false; *item_count];
+                let Some(last_item_live_out_flag) = item_live_out_flags.last_mut() else {
+                    return Interned::default();
+                };
+                *last_item_live_out_flag = true;
+                Intern::intern_owned(self.0.filtered_ops(item_live_out_flags))
+            }
+        }
+        MyMemoize(self).get_owned(item_count)
+    }
+}
+
+pub fn reduce_ops(item_count: usize) -> Interned<[PrefixSumOp]> {
+    PrefixSumAlgorithm::LowLatency.reduce_ops(item_count)
+}
+
+pub fn reduce<T>(items: impl IntoIterator<Item = T>, mut f: impl FnMut(T, T) -> T) -> Option<T> {
+    let mut items: Vec<_> = items.into_iter().map(Some).collect();
+    for op in reduce_ops(items.len()) {
+        let (Some(lhs), Some(rhs)) = (
+            items[op.lhs_index].take(),
+            items[op.rhs_and_dest_index.get()].take(),
+        ) else {
+            unreachable!();
+        };
+        items[op.rhs_and_dest_index.get()] = Some(f(lhs, rhs));
+    }
+    items.last_mut().and_then(Option::take)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn input_strings() -> [String; 9] {
+        std::array::from_fn(|i| String::from_utf8(vec![b'a' + i as u8]).unwrap())
+    }
+
+    #[test]
+    fn test_prefix_sum_strings() {
+        let input = input_strings();
+        let expected: Vec<String> = input
+            .iter()
+            .scan(String::new(), |l, r| {
+                *l += r;
+                Some(l.clone())
+            })
+            .collect();
+        println!("expected: {expected:?}");
+        assert_eq!(
+            *PrefixSumAlgorithm::WorkEfficient
+                .run_on_slice(&mut input.clone(), |l, r| l.to_string() + r),
+            *expected
+        );
+        assert_eq!(
+            *PrefixSumAlgorithm::LowLatency
+                .run_on_slice(&mut input.clone(), |l, r| l.to_string() + r),
+            *expected
+        );
+    }
+
+    #[test]
+    fn test_reduce_string() {
+        let input = input_strings();
+        let expected = input.clone().into_iter().reduce(|l, r| l + &r);
+        assert_eq!(reduce(input, |l, r| l + &r), expected);
+    }
+
+    fn op(lhs_index: usize, rhs_and_dest_index: usize, row: u32) -> PrefixSumOp {
+        PrefixSumOp {
+            lhs_index,
+            rhs_and_dest_index: NonZeroUsize::new(rhs_and_dest_index).expect("should be non-zero"),
+            row,
+        }
+    }
+
+    #[test]
+    fn test_reduce_ops_9() {
+        let expected = vec![
+            op(7, 8, 0),
+            op(5, 6, 0),
+            op(3, 4, 0),
+            op(1, 2, 0),
+            op(6, 8, 1),
+            op(2, 4, 1),
+            op(4, 8, 2),
+            op(0, 8, 3),
+        ];
+        println!("expected: {expected:#?}");
+        let ops = reduce_ops(9);
+        println!("ops: {ops:#?}");
+        assert_eq!(*ops, *expected);
+    }
+
+    #[test]
+    fn test_reduce_ops_8() {
+        let expected = vec![
+            op(6, 7, 0),
+            op(4, 5, 0),
+            op(2, 3, 0),
+            op(0, 1, 0),
+            op(5, 7, 1),
+            op(1, 3, 1),
+            op(3, 7, 2),
+        ];
+        println!("expected: {expected:#?}");
+        let ops = reduce_ops(8);
+        println!("ops: {ops:#?}");
+        assert_eq!(*ops, *expected);
+    }
+
+    #[test]
+    fn test_count_ones() {
+        for width in 0..=10u32 {
+            for v in 0..1u32 << width {
+                let expected = v.count_ones();
+                assert_eq!(
+                    reduce((0..width).map(|i| (v >> i) & 1), |l, r| l + r).unwrap_or(0),
+                    expected,
+                    "v={v:#X}"
+                );
+            }
+        }
+    }
+
+    #[track_caller]
+    fn test_diagram(ops: impl IntoIterator<Item = PrefixSumOp>, item_count: usize, expected: &str) {
+        let text = PrefixSumOp::diagram_with_config(
+            ops,
+            item_count,
+            DiagramConfig {
+                plus: Cow::Borrowed("@"),
+                ..Default::default()
+            },
+        );
+        println!("text:\n{text}\n");
+        assert_eq!(text, expected);
+    }
+
+    #[test]
+    fn test_work_efficient_diagram_16() {
+        let item_count = 16;
+        test_diagram(
+            PrefixSumAlgorithm::WorkEfficient.ops(item_count),
+            item_count,
+            &r"
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
+ ●  |  ●  |  ●  |  ●  |  ●  |  ●  |  ●  |  ●  |
+ |\ |  |\ |  |\ |  |\ |  |\ |  |\ |  |\ |  |\ |
+ | \|  | \|  | \|  | \|  | \|  | \|  | \|  | \|
+ |  @  |  @  |  @  |  @  |  @  |  @  |  @  |  @
+ |  |\ |  |  |  |\ |  |  |  |\ |  |  |  |\ |  |
+ |  | \|  |  |  | \|  |  |  | \|  |  |  | \|  |
+ |  |  X  |  |  |  X  |  |  |  X  |  |  |  X  |
+ |  |  |\ |  |  |  |\ |  |  |  |\ |  |  |  |\ |
+ |  |  | \|  |  |  | \|  |  |  | \|  |  |  | \|
+ |  |  |  @  |  |  |  @  |  |  |  @  |  |  |  @
+ |  |  |  |\ |  |  |  |  |  |  |  |\ |  |  |  |
+ |  |  |  | \|  |  |  |  |  |  |  | \|  |  |  |
+ |  |  |  |  X  |  |  |  |  |  |  |  X  |  |  |
+ |  |  |  |  |\ |  |  |  |  |  |  |  |\ |  |  |
+ |  |  |  |  | \|  |  |  |  |  |  |  | \|  |  |
+ |  |  |  |  |  X  |  |  |  |  |  |  |  X  |  |
+ |  |  |  |  |  |\ |  |  |  |  |  |  |  |\ |  |
+ |  |  |  |  |  | \|  |  |  |  |  |  |  | \|  |
+ |  |  |  |  |  |  X  |  |  |  |  |  |  |  X  |
+ |  |  |  |  |  |  |\ |  |  |  |  |  |  |  |\ |
+ |  |  |  |  |  |  | \|  |  |  |  |  |  |  | \|
+ |  |  |  |  |  |  |  @  |  |  |  |  |  |  |  @
+ |  |  |  |  |  |  |  |\ |  |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  | \|  |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  X  |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |\ |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  | \|  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  X  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |\ |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  | \|  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  X  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |\ |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  | \|  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  X  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |\ |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  | \|  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  X  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |\ |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  | \|  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  X  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |\ |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  | \|  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  X  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |\ |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  | \|
+ |  |  |  |  |  |  |  ●  |  |  |  |  |  |  |  @
+ |  |  |  |  |  |  |  |\ |  |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  | \|  |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  X  |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |\ |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  | \|  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  X  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |\ |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  | \|  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  X  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |\ |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  | \|  |  |  |  |
+ |  |  |  ●  |  |  |  ●  |  |  |  @  |  |  |  |
+ |  |  |  |\ |  |  |  |\ |  |  |  |\ |  |  |  |
+ |  |  |  | \|  |  |  | \|  |  |  | \|  |  |  |
+ |  |  |  |  X  |  |  |  X  |  |  |  X  |  |  |
+ |  |  |  |  |\ |  |  |  |\ |  |  |  |\ |  |  |
+ |  |  |  |  | \|  |  |  | \|  |  |  | \|  |  |
+ |  ●  |  ●  |  @  |  ●  |  @  |  ●  |  @  |  |
+ |  |\ |  |\ |  |\ |  |\ |  |\ |  |\ |  |\ |  |
+ |  | \|  | \|  | \|  | \|  | \|  | \|  | \|  |
+ |  |  @  |  @  |  @  |  @  |  @  |  @  |  @  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
+"[1..], // trim newline at start
+        );
+    }
+
+    #[test]
+    fn test_low_latency_diagram_16() {
+        let item_count = 16;
+        test_diagram(
+            PrefixSumAlgorithm::LowLatency.ops(item_count),
+            item_count,
+            &r"
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
+ ●  ●  ●  ●  ●  ●  ●  ●  ●  ●  ●  ●  ●  ●  ●  |
+ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |
+ | \| \| \| \| \| \| \| \| \| \| \| \| \| \| \|
+ ●  @  @  @  @  @  @  @  @  @  @  @  @  @  @  @
+ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |  |
+ | \| \| \| \| \| \| \| \| \| \| \| \| \| \|  |
+ |  X  X  X  X  X  X  X  X  X  X  X  X  X  X  |
+ |  |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |
+ |  | \| \| \| \| \| \| \| \| \| \| \| \| \| \|
+ ●  ●  @  @  @  @  @  @  @  @  @  @  @  @  @  @
+ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |  |  |  |
+ | \| \| \| \| \| \| \| \| \| \| \| \|  |  |  |
+ |  X  X  X  X  X  X  X  X  X  X  X  X  |  |  |
+ |  |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |  |  |
+ |  | \| \| \| \| \| \| \| \| \| \| \| \|  |  |
+ |  |  X  X  X  X  X  X  X  X  X  X  X  X  |  |
+ |  |  |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |  |
+ |  |  | \| \| \| \| \| \| \| \| \| \| \| \|  |
+ |  |  |  X  X  X  X  X  X  X  X  X  X  X  X  |
+ |  |  |  |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |
+ |  |  |  | \| \| \| \| \| \| \| \| \| \| \| \|
+ ●  ●  ●  ●  @  @  @  @  @  @  @  @  @  @  @  @
+ |\ |\ |\ |\ |\ |\ |\ |\ |  |  |  |  |  |  |  |
+ | \| \| \| \| \| \| \| \|  |  |  |  |  |  |  |
+ |  X  X  X  X  X  X  X  X  |  |  |  |  |  |  |
+ |  |\ |\ |\ |\ |\ |\ |\ |\ |  |  |  |  |  |  |
+ |  | \| \| \| \| \| \| \| \|  |  |  |  |  |  |
+ |  |  X  X  X  X  X  X  X  X  |  |  |  |  |  |
+ |  |  |\ |\ |\ |\ |\ |\ |\ |\ |  |  |  |  |  |
+ |  |  | \| \| \| \| \| \| \| \|  |  |  |  |  |
+ |  |  |  X  X  X  X  X  X  X  X  |  |  |  |  |
+ |  |  |  |\ |\ |\ |\ |\ |\ |\ |\ |  |  |  |  |
+ |  |  |  | \| \| \| \| \| \| \| \|  |  |  |  |
+ |  |  |  |  X  X  X  X  X  X  X  X  |  |  |  |
+ |  |  |  |  |\ |\ |\ |\ |\ |\ |\ |\ |  |  |  |
+ |  |  |  |  | \| \| \| \| \| \| \| \|  |  |  |
+ |  |  |  |  |  X  X  X  X  X  X  X  X  |  |  |
+ |  |  |  |  |  |\ |\ |\ |\ |\ |\ |\ |\ |  |  |
+ |  |  |  |  |  | \| \| \| \| \| \| \| \|  |  |
+ |  |  |  |  |  |  X  X  X  X  X  X  X  X  |  |
+ |  |  |  |  |  |  |\ |\ |\ |\ |\ |\ |\ |\ |  |
+ |  |  |  |  |  |  | \| \| \| \| \| \| \| \|  |
+ |  |  |  |  |  |  |  X  X  X  X  X  X  X  X  |
+ |  |  |  |  |  |  |  |\ |\ |\ |\ |\ |\ |\ |\ |
+ |  |  |  |  |  |  |  | \| \| \| \| \| \| \| \|
+ |  |  |  |  |  |  |  |  @  @  @  @  @  @  @  @
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
+"[1..], // trim newline at start
+        );
+    }
+
+    #[test]
+    fn test_work_efficient_diagram_9() {
+        let item_count = 9;
+        test_diagram(
+            PrefixSumAlgorithm::WorkEfficient.ops(item_count),
+            item_count,
+            &r"
+ |  |  |  |  |  |  |  |  |
+ ●  |  ●  |  ●  |  ●  |  |
+ |\ |  |\ |  |\ |  |\ |  |
+ | \|  | \|  | \|  | \|  |
+ |  @  |  @  |  @  |  @  |
+ |  |\ |  |  |  |\ |  |  |
+ |  | \|  |  |  | \|  |  |
+ |  |  X  |  |  |  X  |  |
+ |  |  |\ |  |  |  |\ |  |
+ |  |  | \|  |  |  | \|  |
+ |  |  |  @  |  |  |  @  |
+ |  |  |  |\ |  |  |  |  |
+ |  |  |  | \|  |  |  |  |
+ |  |  |  |  X  |  |  |  |
+ |  |  |  |  |\ |  |  |  |
+ |  |  |  |  | \|  |  |  |
+ |  |  |  |  |  X  |  |  |
+ |  |  |  |  |  |\ |  |  |
+ |  |  |  |  |  | \|  |  |
+ |  |  |  |  |  |  X  |  |
+ |  |  |  |  |  |  |\ |  |
+ |  |  |  |  |  |  | \|  |
+ |  |  |  ●  |  |  |  @  |
+ |  |  |  |\ |  |  |  |  |
+ |  |  |  | \|  |  |  |  |
+ |  |  |  |  X  |  |  |  |
+ |  |  |  |  |\ |  |  |  |
+ |  |  |  |  | \|  |  |  |
+ |  ●  |  ●  |  @  |  ●  |
+ |  |\ |  |\ |  |\ |  |\ |
+ |  | \|  | \|  | \|  | \|
+ |  |  @  |  @  |  @  |  @
+ |  |  |  |  |  |  |  |  |
+"[1..], // trim newline at start
+        );
+    }
+
+    #[test]
+    fn test_low_latency_diagram_9() {
+        let item_count = 9;
+        test_diagram(
+            PrefixSumAlgorithm::LowLatency.ops(item_count),
+            item_count,
+            &r"
+ |  |  |  |  |  |  |  |  |
+ ●  ●  ●  ●  ●  ●  ●  ●  |
+ |\ |\ |\ |\ |\ |\ |\ |\ |
+ | \| \| \| \| \| \| \| \|
+ ●  @  @  @  @  @  @  @  @
+ |\ |\ |\ |\ |\ |\ |\ |  |
+ | \| \| \| \| \| \| \|  |
+ |  X  X  X  X  X  X  X  |
+ |  |\ |\ |\ |\ |\ |\ |\ |
+ |  | \| \| \| \| \| \| \|
+ ●  ●  @  @  @  @  @  @  @
+ |\ |\ |\ |\ |\ |  |  |  |
+ | \| \| \| \| \|  |  |  |
+ |  X  X  X  X  X  |  |  |
+ |  |\ |\ |\ |\ |\ |  |  |
+ |  | \| \| \| \| \|  |  |
+ |  |  X  X  X  X  X  |  |
+ |  |  |\ |\ |\ |\ |\ |  |
+ |  |  | \| \| \| \| \|  |
+ |  |  |  X  X  X  X  X  |
+ |  |  |  |\ |\ |\ |\ |\ |
+ |  |  |  | \| \| \| \| \|
+ ●  |  |  |  @  @  @  @  @
+ |\ |  |  |  |  |  |  |  |
+ | \|  |  |  |  |  |  |  |
+ |  X  |  |  |  |  |  |  |
+ |  |\ |  |  |  |  |  |  |
+ |  | \|  |  |  |  |  |  |
+ |  |  X  |  |  |  |  |  |
+ |  |  |\ |  |  |  |  |  |
+ |  |  | \|  |  |  |  |  |
+ |  |  |  X  |  |  |  |  |
+ |  |  |  |\ |  |  |  |  |
+ |  |  |  | \|  |  |  |  |
+ |  |  |  |  X  |  |  |  |
+ |  |  |  |  |\ |  |  |  |
+ |  |  |  |  | \|  |  |  |
+ |  |  |  |  |  X  |  |  |
+ |  |  |  |  |  |\ |  |  |
+ |  |  |  |  |  | \|  |  |
+ |  |  |  |  |  |  X  |  |
+ |  |  |  |  |  |  |\ |  |
+ |  |  |  |  |  |  | \|  |
+ |  |  |  |  |  |  |  X  |
+ |  |  |  |  |  |  |  |\ |
+ |  |  |  |  |  |  |  | \|
+ |  |  |  |  |  |  |  |  @
+ |  |  |  |  |  |  |  |  |
+"[1..], // trim newline at start
+        );
+    }
+
+    #[test]
+    fn test_reduce_diagram_16() {
+        let item_count = 16;
+        test_diagram(
+            reduce_ops(item_count),
+            item_count,
+            &r"
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
+ ●  |  ●  |  ●  |  ●  |  ●  |  ●  |  ●  |  ●  |
+ |\ |  |\ |  |\ |  |\ |  |\ |  |\ |  |\ |  |\ |
+ | \|  | \|  | \|  | \|  | \|  | \|  | \|  | \|
+ |  @  |  @  |  @  |  @  |  @  |  @  |  @  |  @
+ |  |\ |  |  |  |\ |  |  |  |\ |  |  |  |\ |  |
+ |  | \|  |  |  | \|  |  |  | \|  |  |  | \|  |
+ |  |  X  |  |  |  X  |  |  |  X  |  |  |  X  |
+ |  |  |\ |  |  |  |\ |  |  |  |\ |  |  |  |\ |
+ |  |  | \|  |  |  | \|  |  |  | \|  |  |  | \|
+ |  |  |  @  |  |  |  @  |  |  |  @  |  |  |  @
+ |  |  |  |\ |  |  |  |  |  |  |  |\ |  |  |  |
+ |  |  |  | \|  |  |  |  |  |  |  | \|  |  |  |
+ |  |  |  |  X  |  |  |  |  |  |  |  X  |  |  |
+ |  |  |  |  |\ |  |  |  |  |  |  |  |\ |  |  |
+ |  |  |  |  | \|  |  |  |  |  |  |  | \|  |  |
+ |  |  |  |  |  X  |  |  |  |  |  |  |  X  |  |
+ |  |  |  |  |  |\ |  |  |  |  |  |  |  |\ |  |
+ |  |  |  |  |  | \|  |  |  |  |  |  |  | \|  |
+ |  |  |  |  |  |  X  |  |  |  |  |  |  |  X  |
+ |  |  |  |  |  |  |\ |  |  |  |  |  |  |  |\ |
+ |  |  |  |  |  |  | \|  |  |  |  |  |  |  | \|
+ |  |  |  |  |  |  |  @  |  |  |  |  |  |  |  @
+ |  |  |  |  |  |  |  |\ |  |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  | \|  |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  X  |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |\ |  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  | \|  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  X  |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |\ |  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  | \|  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  X  |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |\ |  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  | \|  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  X  |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |\ |  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  | \|  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  X  |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |\ |  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  | \|  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  X  |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |\ |  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  | \|  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  X  |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |\ |
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  | \|
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  @
+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
+"[1..], // trim newline at start
+        );
+    }
+
+    #[test]
+    fn test_reduce_diagram_9() {
+        let item_count = 9;
+        test_diagram(
+            reduce_ops(item_count),
+            item_count,
+            &r"
+ |  |  |  |  |  |  |  |  |
+ |  ●  |  ●  |  ●  |  ●  |
+ |  |\ |  |\ |  |\ |  |\ |
+ |  | \|  | \|  | \|  | \|
+ |  |  @  |  @  |  @  |  @
+ |  |  |\ |  |  |  |\ |  |
+ |  |  | \|  |  |  | \|  |
+ |  |  |  X  |  |  |  X  |
+ |  |  |  |\ |  |  |  |\ |
+ |  |  |  | \|  |  |  | \|
+ |  |  |  |  @  |  |  |  @
+ |  |  |  |  |\ |  |  |  |
+ |  |  |  |  | \|  |  |  |
+ |  |  |  |  |  X  |  |  |
+ |  |  |  |  |  |\ |  |  |
+ |  |  |  |  |  | \|  |  |
+ |  |  |  |  |  |  X  |  |
+ |  |  |  |  |  |  |\ |  |
+ |  |  |  |  |  |  | \|  |
+ |  |  |  |  |  |  |  X  |
+ |  |  |  |  |  |  |  |\ |
+ |  |  |  |  |  |  |  | \|
+ ●  |  |  |  |  |  |  |  @
+ |\ |  |  |  |  |  |  |  |
+ | \|  |  |  |  |  |  |  |
+ |  X  |  |  |  |  |  |  |
+ |  |\ |  |  |  |  |  |  |
+ |  | \|  |  |  |  |  |  |
+ |  |  X  |  |  |  |  |  |
+ |  |  |\ |  |  |  |  |  |
+ |  |  | \|  |  |  |  |  |
+ |  |  |  X  |  |  |  |  |
+ |  |  |  |\ |  |  |  |  |
+ |  |  |  | \|  |  |  |  |
+ |  |  |  |  X  |  |  |  |
+ |  |  |  |  |\ |  |  |  |
+ |  |  |  |  | \|  |  |  |
+ |  |  |  |  |  X  |  |  |
+ |  |  |  |  |  |\ |  |  |
+ |  |  |  |  |  | \|  |  |
+ |  |  |  |  |  |  X  |  |
+ |  |  |  |  |  |  |\ |  |
+ |  |  |  |  |  |  | \|  |
+ |  |  |  |  |  |  |  X  |
+ |  |  |  |  |  |  |  |\ |
+ |  |  |  |  |  |  |  | \|
+ |  |  |  |  |  |  |  |  @
+ |  |  |  |  |  |  |  |  |
+"[1..], // trim newline at start
+        );
+    }
+}

crates/fayalite/src/util/test_hasher.rs

@@ -0,0 +1,240 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+#![cfg(feature = "unstable-test-hasher")]
+
+use std::{
+    fmt::Write as _,
+    hash::{BuildHasher, Hash, Hasher},
+    io::Write as _,
+    marker::PhantomData,
+    sync::LazyLock,
+};
+
+type BoxDynHasher = Box<dyn Hasher + Send + Sync>;
+type BoxDynBuildHasher = Box<dyn DynBuildHasherTrait + Send + Sync>;
+type BoxDynMakeBuildHasher = Box<dyn Fn() -> BoxDynBuildHasher + Send + Sync>;
+
+trait TryGetDynBuildHasher: Copy {
+    type Type;
+    fn try_get_make_build_hasher(self) -> Option<BoxDynMakeBuildHasher>;
+}
+
+impl<T> TryGetDynBuildHasher for PhantomData<T> {
+    type Type = T;
+    fn try_get_make_build_hasher(self) -> Option<BoxDynMakeBuildHasher> {
+        None
+    }
+}
+
+impl<T: Default + BuildHasher<Hasher: Send + Sync + 'static> + Send + Sync + 'static + Clone>
+    TryGetDynBuildHasher for &'_ PhantomData<T>
+{
+    type Type = T;
+    fn try_get_make_build_hasher(self) -> Option<BoxDynMakeBuildHasher> {
+        Some(Box::new(|| Box::<DynBuildHasher<T>>::default()))
+    }
+}
+
+#[derive(Default, Clone)]
+struct DynBuildHasher<T>(T);
+
+trait DynBuildHasherTrait: BuildHasher<Hasher = BoxDynHasher> {
+    fn clone_dyn_build_hasher(&self) -> BoxDynBuildHasher;
+}
+
+impl<BH: BuildHasher<Hasher: Send + Sync + 'static>> BuildHasher for DynBuildHasher<BH> {
+    type Hasher = BoxDynHasher;
+
+    fn build_hasher(&self) -> Self::Hasher {
+        Box::new(self.0.build_hasher())
+    }
+
+    fn hash_one<T: Hash>(&self, x: T) -> u64 {
+        self.0.hash_one(x)
+    }
+}
+
+impl<BH> DynBuildHasherTrait for DynBuildHasher<BH>
+where
+    Self: Clone + BuildHasher<Hasher = BoxDynHasher> + Send + Sync + 'static,
+{
+    fn clone_dyn_build_hasher(&self) -> BoxDynBuildHasher {
+        Box::new(self.clone())
+    }
+}
+
+pub struct DefaultBuildHasher(BoxDynBuildHasher);
+
+impl Clone for DefaultBuildHasher {
+    fn clone(&self) -> Self {
+        DefaultBuildHasher(self.0.clone_dyn_build_hasher())
+    }
+}
+
+const ENV_VAR_NAME: &'static str = "FAYALITE_TEST_HASHER";
+
+struct EnvVarValue {
+    key: &'static str,
+    try_get_make_build_hasher: fn() -> Option<BoxDynMakeBuildHasher>,
+    description: &'static str,
+}
+
+macro_rules! env_var_value {
+    (
+        key: $key:literal,
+        build_hasher: $build_hasher:ty,
+        description: $description:literal,
+    ) => {
+        EnvVarValue {
+            key: $key,
+            try_get_make_build_hasher: || {
+                // use rust method resolution to detect if $build_hasher is usable
+                // (e.g. hashbrown's hasher won't be usable without the right feature enabled)
+                (&PhantomData::<DynBuildHasher<$build_hasher>>).try_get_make_build_hasher()
+            },
+            description: $description,
+        }
+    };
+}
+
+#[derive(Default)]
+struct AlwaysZeroHasher;
+
+impl Hasher for AlwaysZeroHasher {
+    fn write(&mut self, _bytes: &[u8]) {}
+    fn finish(&self) -> u64 {
+        0
+    }
+}
+
+const ENV_VAR_VALUES: &'static [EnvVarValue] = &[
+    env_var_value! {
+        key: "std",
+        build_hasher: std::hash::RandomState,
+        description: "use std::hash::RandomState",
+    },
+    env_var_value! {
+        key: "hashbrown",
+        build_hasher: hashbrown::DefaultHashBuilder,
+        description: "use hashbrown's DefaultHashBuilder",
+    },
+    env_var_value! {
+        key: "always_zero",
+        build_hasher: std::hash::BuildHasherDefault<AlwaysZeroHasher>,
+        description: "use a hasher that always returns 0 for all hashes,\n    \
+        this is useful for checking that PartialEq impls are correct",
+    },
+];
+
+fn report_bad_env_var(msg: impl std::fmt::Display) -> ! {
+    let mut msg = format!("{ENV_VAR_NAME}: {msg}\n");
+    for &EnvVarValue {
+        key,
+        try_get_make_build_hasher,
+        description,
+    } in ENV_VAR_VALUES
+    {
+        let availability = match try_get_make_build_hasher() {
+            Some(_) => "available",
+            None => "unavailable",
+        };
+        writeln!(msg, "{key}: ({availability})\n    {description}").expect("can't fail");
+    }
+    std::io::stderr()
+        .write_all(msg.as_bytes())
+        .expect("should be able to write to stderr");
+    std::process::abort();
+}
+
+impl Default for DefaultBuildHasher {
+    fn default() -> Self {
+        static DEFAULT_FN: LazyLock<BoxDynMakeBuildHasher> = LazyLock::new(|| {
+            let var = std::env::var_os(ENV_VAR_NAME);
+            let var = var.as_deref().unwrap_or("std".as_ref());
+            for &EnvVarValue {
+                key,
+                try_get_make_build_hasher,
+                description: _,
+            } in ENV_VAR_VALUES
+            {
+                if var.as_encoded_bytes().eq_ignore_ascii_case(key.as_bytes()) {
+                    return try_get_make_build_hasher().unwrap_or_else(|| {
+                        report_bad_env_var(format_args!(
+                            "unavailable hasher: {key} (is the appropriate feature enabled?)"
+                        ));
+                    });
+                }
+            }
+            report_bad_env_var(format_args!("unrecognized hasher: {var:?}"));
+        });
+        Self(DEFAULT_FN())
+    }
+}
+
+pub struct DefaultHasher(BoxDynHasher);
+
+impl BuildHasher for DefaultBuildHasher {
+    type Hasher = DefaultHasher;
+
+    fn build_hasher(&self) -> Self::Hasher {
+        DefaultHasher(self.0.build_hasher())
+    }
+}
+
+impl Hasher for DefaultHasher {
+    fn finish(&self) -> u64 {
+        self.0.finish()
+    }
+
+    fn write(&mut self, bytes: &[u8]) {
+        self.0.write(bytes)
+    }
+
+    fn write_u8(&mut self, i: u8) {
+        self.0.write_u8(i)
+    }
+
+    fn write_u16(&mut self, i: u16) {
+        self.0.write_u16(i)
+    }
+
+    fn write_u32(&mut self, i: u32) {
+        self.0.write_u32(i)
+    }
+
+    fn write_u64(&mut self, i: u64) {
+        self.0.write_u64(i)
+    }
+
+    fn write_u128(&mut self, i: u128) {
+        self.0.write_u128(i)
+    }
+
+    fn write_usize(&mut self, i: usize) {
+        self.0.write_usize(i)
+    }
+
+    fn write_i8(&mut self, i: i8) {
+        self.0.write_i8(i)
+    }
+
+    fn write_i16(&mut self, i: i16) {
+        self.0.write_i16(i)
+    }
+
+    fn write_i32(&mut self, i: i32) {
+        self.0.write_i32(i)
+    }
+
+    fn write_i64(&mut self, i: i64) {
+        self.0.write_i64(i)
+    }
+
+    fn write_i128(&mut self, i: i128) {
+        self.0.write_i128(i)
+    }
+
+    fn write_isize(&mut self, i: isize) {
+        self.0.write_isize(i)
+    }
+}

crates/fayalite/tests/hdl_types.rs

@@ -4,11 +4,17 @@ use fayalite::{
     bundle::BundleType,
     enum_::EnumType,
     int::{BoolOrIntType, IntType},
+    phantom_const::PhantomConst,
     prelude::*,
     ty::StaticType,
 };
 use std::marker::PhantomData;
 
+#[hdl(outline_generated)]
+pub struct MyConstSize<V: Size> {
+    pub size: PhantomConst<UIntType<V>>,
+}
+
 #[hdl(outline_generated)]
 pub struct S<T, Len: Size, T2> {
     pub a: T,

crates/fayalite/tests/module.rs

@@ -1,8 +1,13 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 // See Notices.txt for copyright information
 use fayalite::{
-    assert_export_firrtl, firrtl::ExportOptions, intern::Intern,
-    module::transform::simplify_enums::SimplifyEnumsKind, prelude::*, reset::ResetType,
+    assert_export_firrtl,
+    firrtl::ExportOptions,
+    int::{UIntInRange, UIntInRangeInclusive},
+    intern::Intern,
+    module::transform::simplify_enums::SimplifyEnumsKind,
+    prelude::*,
+    reset::ResetType,
     ty::StaticType,
 };
 use serde_json::json;
@@ -191,10 +196,14 @@ circuit check_array_repeat:
     };
 }
 
+pub trait UnknownTrait {}
+
+impl<T: ?Sized> UnknownTrait for T {}
+
 #[hdl_module(outline_generated)]
 pub fn check_skipped_generics<T, #[hdl(skip)] U, const N: usize, #[hdl(skip)] const M: usize>(v: U)
 where
-    T: StaticType,
+    T: StaticType + UnknownTrait,
     ConstUsize<N>: KnownSize,
     U: std::fmt::Display,
 {
@@ -376,18 +385,18 @@ circuit check_written_inside_both_if_else:
     };
 }
 
-#[hdl(outline_generated)]
+#[hdl(outline_generated, cmp_eq)]
 pub struct TestStruct<T> {
     pub a: T,
     pub b: UInt<8>,
 }
 
-#[hdl(outline_generated)]
+#[hdl(outline_generated, cmp_eq)]
 pub struct TestStruct2 {
     pub v: UInt<8>,
 }
 
-#[hdl(outline_generated)]
+#[hdl(outline_generated, cmp_eq)]
 pub struct TestStruct3 {}
 
 #[hdl_module(outline_generated)]
@@ -4421,3 +4430,204 @@ circuit check_let_patterns:
 ",
     };
 }
+
+#[hdl_module(outline_generated)]
+pub fn check_struct_cmp_eq() {
+    #[hdl]
+    let tuple_lhs: (UInt<1>, SInt<1>, Bool) = m.input();
+    #[hdl]
+    let tuple_rhs: (UInt<1>, SInt<1>, Bool) = m.input();
+    #[hdl]
+    let tuple_cmp_eq: Bool = m.output();
+    connect(tuple_cmp_eq, tuple_lhs.cmp_eq(tuple_rhs));
+    #[hdl]
+    let tuple_cmp_ne: Bool = m.output();
+    connect(tuple_cmp_ne, tuple_lhs.cmp_ne(tuple_rhs));
+
+    #[hdl]
+    let test_struct_lhs: TestStruct<SInt<8>> = m.input();
+    #[hdl]
+    let test_struct_rhs: TestStruct<SInt<8>> = m.input();
+    #[hdl]
+    let test_struct_cmp_eq: Bool = m.output();
+    connect(test_struct_cmp_eq, test_struct_lhs.cmp_eq(test_struct_rhs));
+    #[hdl]
+    let test_struct_cmp_ne: Bool = m.output();
+    connect(test_struct_cmp_ne, test_struct_lhs.cmp_ne(test_struct_rhs));
+
+    #[hdl]
+    let test_struct_2_lhs: TestStruct2 = m.input();
+    #[hdl]
+    let test_struct_2_rhs: TestStruct2 = m.input();
+    #[hdl]
+    let test_struct_2_cmp_eq: Bool = m.output();
+    connect(
+        test_struct_2_cmp_eq,
+        test_struct_2_lhs.cmp_eq(test_struct_2_rhs),
+    );
+    #[hdl]
+    let test_struct_2_cmp_ne: Bool = m.output();
+    connect(
+        test_struct_2_cmp_ne,
+        test_struct_2_lhs.cmp_ne(test_struct_2_rhs),
+    );
+
+    #[hdl]
+    let test_struct_3_lhs: TestStruct3 = m.input();
+    #[hdl]
+    let test_struct_3_rhs: TestStruct3 = m.input();
+    #[hdl]
+    let test_struct_3_cmp_eq: Bool = m.output();
+    connect(
+        test_struct_3_cmp_eq,
+        test_struct_3_lhs.cmp_eq(test_struct_3_rhs),
+    );
+    #[hdl]
+    let test_struct_3_cmp_ne: Bool = m.output();
+    connect(
+        test_struct_3_cmp_ne,
+        test_struct_3_lhs.cmp_ne(test_struct_3_rhs),
+    );
+}
+
+#[test]
+fn test_struct_cmp_eq() {
+    let _n = SourceLocation::normalize_files_for_tests();
+    let m = check_struct_cmp_eq();
+    dbg!(m);
+    #[rustfmt::skip] // work around https://github.com/rust-lang/rustfmt/issues/6161
+    assert_export_firrtl! {
+        m =>
+        "/test/check_struct_cmp_eq.fir": r"FIRRTL version 3.2.0
+circuit check_struct_cmp_eq:
+    type Ty0 = {`0`: UInt<1>, `1`: SInt<1>, `2`: UInt<1>}
+    type Ty1 = {a: SInt<8>, b: UInt<8>}
+    type Ty2 = {v: UInt<8>}
+    type Ty3 = {}
+    module check_struct_cmp_eq: @[module-XXXXXXXXXX.rs 1:1]
+        input tuple_lhs: Ty0 @[module-XXXXXXXXXX.rs 2:1]
+        input tuple_rhs: Ty0 @[module-XXXXXXXXXX.rs 3:1]
+        output tuple_cmp_eq: UInt<1> @[module-XXXXXXXXXX.rs 4:1]
+        output tuple_cmp_ne: UInt<1> @[module-XXXXXXXXXX.rs 6:1]
+        input test_struct_lhs: Ty1 @[module-XXXXXXXXXX.rs 8:1]
+        input test_struct_rhs: Ty1 @[module-XXXXXXXXXX.rs 9:1]
+        output test_struct_cmp_eq: UInt<1> @[module-XXXXXXXXXX.rs 10:1]
+        output test_struct_cmp_ne: UInt<1> @[module-XXXXXXXXXX.rs 12:1]
+        input test_struct_2_lhs: Ty2 @[module-XXXXXXXXXX.rs 14:1]
+        input test_struct_2_rhs: Ty2 @[module-XXXXXXXXXX.rs 15:1]
+        output test_struct_2_cmp_eq: UInt<1> @[module-XXXXXXXXXX.rs 16:1]
+        output test_struct_2_cmp_ne: UInt<1> @[module-XXXXXXXXXX.rs 18:1]
+        input test_struct_3_lhs: Ty3 @[module-XXXXXXXXXX.rs 20:1]
+        input test_struct_3_rhs: Ty3 @[module-XXXXXXXXXX.rs 21:1]
+        output test_struct_3_cmp_eq: UInt<1> @[module-XXXXXXXXXX.rs 22:1]
+        output test_struct_3_cmp_ne: UInt<1> @[module-XXXXXXXXXX.rs 24:1]
+        wire _array_literal_expr: UInt<1>[3]
+        connect _array_literal_expr[0], eq(tuple_lhs.`0`, tuple_rhs.`0`)
+        connect _array_literal_expr[1], eq(tuple_lhs.`1`, tuple_rhs.`1`)
+        connect _array_literal_expr[2], eq(tuple_lhs.`2`, tuple_rhs.`2`)
+        wire _cast_array_to_bits_expr: UInt<1>[3]
+        connect _cast_array_to_bits_expr[0], _array_literal_expr[0]
+        connect _cast_array_to_bits_expr[1], _array_literal_expr[1]
+        connect _cast_array_to_bits_expr[2], _array_literal_expr[2]
+        wire _cast_to_bits_expr: UInt<3>
+        connect _cast_to_bits_expr, cat(_cast_array_to_bits_expr[2], cat(_cast_array_to_bits_expr[1], _cast_array_to_bits_expr[0]))
+        connect tuple_cmp_eq, andr(_cast_to_bits_expr) @[module-XXXXXXXXXX.rs 5:1]
+        wire _array_literal_expr_1: UInt<1>[3]
+        connect _array_literal_expr_1[0], neq(tuple_lhs.`0`, tuple_rhs.`0`)
+        connect _array_literal_expr_1[1], neq(tuple_lhs.`1`, tuple_rhs.`1`)
+        connect _array_literal_expr_1[2], neq(tuple_lhs.`2`, tuple_rhs.`2`)
+        wire _cast_array_to_bits_expr_1: UInt<1>[3]
+        connect _cast_array_to_bits_expr_1[0], _array_literal_expr_1[0]
+        connect _cast_array_to_bits_expr_1[1], _array_literal_expr_1[1]
+        connect _cast_array_to_bits_expr_1[2], _array_literal_expr_1[2]
+        wire _cast_to_bits_expr_1: UInt<3>
+        connect _cast_to_bits_expr_1, cat(_cast_array_to_bits_expr_1[2], cat(_cast_array_to_bits_expr_1[1], _cast_array_to_bits_expr_1[0]))
+        connect tuple_cmp_ne, orr(_cast_to_bits_expr_1) @[module-XXXXXXXXXX.rs 7:1]
+        connect test_struct_cmp_eq, and(eq(test_struct_lhs.a, test_struct_rhs.a), eq(test_struct_lhs.b, test_struct_rhs.b)) @[module-XXXXXXXXXX.rs 11:1]
+        connect test_struct_cmp_ne, or(neq(test_struct_lhs.a, test_struct_rhs.a), neq(test_struct_lhs.b, test_struct_rhs.b)) @[module-XXXXXXXXXX.rs 13:1]
+        connect test_struct_2_cmp_eq, eq(test_struct_2_lhs.v, test_struct_2_rhs.v) @[module-XXXXXXXXXX.rs 17:1]
+        connect test_struct_2_cmp_ne, neq(test_struct_2_lhs.v, test_struct_2_rhs.v) @[module-XXXXXXXXXX.rs 19:1]
+        connect test_struct_3_cmp_eq, UInt<1>(0h1) @[module-XXXXXXXXXX.rs 23:1]
+        connect test_struct_3_cmp_ne, UInt<1>(0h0) @[module-XXXXXXXXXX.rs 25:1]
+",
+    };
+}
+
+#[hdl_module(outline_generated)]
+pub fn check_uint_in_range() {
+    #[hdl]
+    let i_0_to_1: UIntInRange<0, 1> = m.input();
+    #[hdl]
+    let i_0_to_2: UIntInRange<0, 2> = m.input();
+    #[hdl]
+    let i_0_to_3: UIntInRange<0, 3> = m.input();
+    #[hdl]
+    let i_0_to_4: UIntInRange<0, 4> = m.input();
+    #[hdl]
+    let i_0_to_7: UIntInRange<0, 7> = m.input();
+    #[hdl]
+    let i_0_to_8: UIntInRange<0, 8> = m.input();
+    #[hdl]
+    let i_0_to_9: UIntInRange<0, 9> = m.input();
+    #[hdl]
+    let i_0_through_0: UIntInRangeInclusive<0, 0> = m.input();
+    #[hdl]
+    let i_0_through_1: UIntInRangeInclusive<0, 1> = m.input();
+    #[hdl]
+    let i_0_through_2: UIntInRangeInclusive<0, 2> = m.input();
+    #[hdl]
+    let i_0_through_3: UIntInRangeInclusive<0, 3> = m.input();
+    #[hdl]
+    let i_0_through_4: UIntInRangeInclusive<0, 4> = m.input();
+    #[hdl]
+    let i_0_through_7: UIntInRangeInclusive<0, 7> = m.input();
+    #[hdl]
+    let i_0_through_8: UIntInRangeInclusive<0, 8> = m.input();
+    #[hdl]
+    let i_0_through_9: UIntInRangeInclusive<0, 9> = m.input();
+}
+
+#[test]
+fn test_uint_in_range() {
+    let _n = SourceLocation::normalize_files_for_tests();
+    let m = check_uint_in_range();
+    dbg!(m);
+    #[rustfmt::skip] // work around https://github.com/rust-lang/rustfmt/issues/6161
+    assert_export_firrtl! {
+        m =>
+        "/test/check_uint_in_range.fir": r"FIRRTL version 3.2.0
+circuit check_uint_in_range:
+    type Ty0 = {value: UInt<0>, range: {}}
+    type Ty1 = {value: UInt<1>, range: {}}
+    type Ty2 = {value: UInt<2>, range: {}}
+    type Ty3 = {value: UInt<2>, range: {}}
+    type Ty4 = {value: UInt<3>, range: {}}
+    type Ty5 = {value: UInt<3>, range: {}}
+    type Ty6 = {value: UInt<4>, range: {}}
+    type Ty7 = {value: UInt<0>, range: {}}
+    type Ty8 = {value: UInt<1>, range: {}}
+    type Ty9 = {value: UInt<2>, range: {}}
+    type Ty10 = {value: UInt<2>, range: {}}
+    type Ty11 = {value: UInt<3>, range: {}}
+    type Ty12 = {value: UInt<3>, range: {}}
+    type Ty13 = {value: UInt<4>, range: {}}
+    type Ty14 = {value: UInt<4>, range: {}}
+    module check_uint_in_range: @[module-XXXXXXXXXX.rs 1:1]
+        input i_0_to_1: Ty0 @[module-XXXXXXXXXX.rs 2:1]
+        input i_0_to_2: Ty1 @[module-XXXXXXXXXX.rs 3:1]
+        input i_0_to_3: Ty2 @[module-XXXXXXXXXX.rs 4:1]
+        input i_0_to_4: Ty3 @[module-XXXXXXXXXX.rs 5:1]
+        input i_0_to_7: Ty4 @[module-XXXXXXXXXX.rs 6:1]
+        input i_0_to_8: Ty5 @[module-XXXXXXXXXX.rs 7:1]
+        input i_0_to_9: Ty6 @[module-XXXXXXXXXX.rs 8:1]
+        input i_0_through_0: Ty7 @[module-XXXXXXXXXX.rs 9:1]
+        input i_0_through_1: Ty8 @[module-XXXXXXXXXX.rs 10:1]
+        input i_0_through_2: Ty9 @[module-XXXXXXXXXX.rs 11:1]
+        input i_0_through_3: Ty10 @[module-XXXXXXXXXX.rs 12:1]
+        input i_0_through_4: Ty11 @[module-XXXXXXXXXX.rs 13:1]
+        input i_0_through_7: Ty12 @[module-XXXXXXXXXX.rs 14:1]
+        input i_0_through_8: Ty13 @[module-XXXXXXXXXX.rs 15:1]
+        input i_0_through_9: Ty14 @[module-XXXXXXXXXX.rs 16:1]
+",
+    };
+}

crates/fayalite/tests/sim.rs

@@ -2,11 +2,11 @@
 // See Notices.txt for copyright information
 
 use fayalite::{
-    int::UIntValue,
+    memory::{ReadStruct, ReadWriteStruct, WriteStruct},
+    module::{instance_with_loc, reg_builder_with_loc},
     prelude::*,
     reset::ResetType,
-    sim::{time::SimDuration, vcd::VcdWriterDecls, Simulation, ToSimValue},
-    ty::StaticType,
+    sim::vcd::VcdWriterDecls,
     util::RcWriter,
 };
 use std::num::NonZeroUsize;
@@ -316,8 +316,13 @@ pub fn enums() {
     let which_out: UInt<2> = m.output();
     #[hdl]
     let data_out: UInt<4> = m.output();
+    let b_out_ty = HdlOption[(UInt[1], Bool)];
     #[hdl]
-    let b_out: HdlOption<(UInt<1>, Bool)> = m.output();
+    let b_out: HdlOption<(UInt, Bool)> = m.output(HdlOption[(UInt[1], Bool)]);
+    #[hdl]
+    let b2_out: HdlOption<(UInt<1>, Bool)> = m.output();
+
+    connect_any(b2_out, b_out);
 
     #[hdl]
     struct MyStruct<T> {
@@ -357,7 +362,7 @@ pub fn enums() {
         }
     }
 
-    connect(b_out, HdlNone());
+    connect(b_out, b_out_ty.HdlNone());
 
     #[hdl]
     match the_reg {
@@ -368,7 +373,7 @@ pub fn enums() {
         MyEnum::B(v) => {
             connect(which_out, 1_hdl_u2);
             connect_any(data_out, v.0 | (v.1.cast_to_static::<UInt<1>>() << 1));
-            connect(b_out, HdlSome(v));
+            connect_any(b_out, HdlSome(v));
         }
         MyEnum::C(v) => {
             connect(which_out, 2_hdl_u2);
@@ -384,132 +389,136 @@ fn test_enums() {
     let mut sim = Simulation::new(enums());
     let mut writer = RcWriter::default();
     sim.add_trace_writer(VcdWriterDecls::new(writer.clone()));
-    sim.write_clock(sim.io().cd.clk, false);
-    sim.write_reset(sim.io().cd.rst, true);
-    sim.write_bool(sim.io().en, false);
-    sim.write_bool_or_int(sim.io().which_in, 0_hdl_u2);
-    sim.write_bool_or_int(sim.io().data_in, 0_hdl_u4);
+    sim.write(sim.io().cd.clk, false);
+    sim.write(sim.io().cd.rst, true);
+    sim.write(sim.io().en, false);
+    sim.write(sim.io().which_in, 0_hdl_u2);
+    sim.write(sim.io().data_in, 0_hdl_u4);
     sim.advance_time(SimDuration::from_micros(1));
-    sim.write_clock(sim.io().cd.clk, true);
+    sim.write(sim.io().cd.clk, true);
     sim.advance_time(SimDuration::from_nanos(100));
-    sim.write_reset(sim.io().cd.rst, false);
+    sim.write(sim.io().cd.rst, false);
     sim.advance_time(SimDuration::from_nanos(900));
-    type BOutTy = HdlOption<(UInt<1>, Bool)>;
-    #[derive(Debug)]
-    struct IO {
-        en: bool,
-        which_in: u8,
-        data_in: u8,
-        which_out: u8,
-        data_out: u8,
-        b_out: Expr<BOutTy>,
-    }
-    impl PartialEq for IO {
-        fn eq(&self, other: &Self) -> bool {
-            let Self {
-                en,
-                which_in,
-                data_in,
-                which_out,
-                data_out,
-                b_out,
-            } = *self;
-            en == other.en
-                && which_in == other.which_in
-                && data_in == other.data_in
-                && which_out == other.which_out
-                && data_out == other.data_out
-                && b_out.to_sim_value(BOutTy::TYPE) == other.b_out.to_sim_value(BOutTy::TYPE)
-        }
+    #[hdl(cmp_eq)]
+    struct IO<W: Size> {
+        en: Bool,
+        which_in: UInt<2>,
+        data_in: UInt<4>,
+        which_out: UInt<2>,
+        data_out: UInt<4>,
+        b_out: HdlOption<(UIntType<W>, Bool)>,
+        b2_out: HdlOption<(UInt<1>, Bool)>,
     }
+    let io_ty = IO[1];
     let io_cycles = [
-        IO {
+        #[hdl(sim)]
+        IO::<_> {
             en: false,
-            which_in: 0,
-            data_in: 0,
-            which_out: 0,
-            data_out: 0,
-            b_out: HdlNone(),
+            which_in: 0_hdl_u2,
+            data_in: 0_hdl_u4,
+            which_out: 0_hdl_u2,
+            data_out: 0_hdl_u4,
+            b_out: #[hdl(sim)]
+            (io_ty.b_out).HdlNone(),
+            b2_out: #[hdl(sim)]
+            HdlNone(),
         },
-        IO {
+        #[hdl(sim)]
+        IO::<_> {
             en: true,
-            which_in: 1,
-            data_in: 0,
-            which_out: 0,
-            data_out: 0,
-            b_out: HdlNone(),
+            which_in: 1_hdl_u2,
+            data_in: 0_hdl_u4,
+            which_out: 0_hdl_u2,
+            data_out: 0_hdl_u4,
+            b_out: #[hdl(sim)]
+            (io_ty.b_out).HdlNone(),
+            b2_out: #[hdl(sim)]
+            HdlNone(),
         },
-        IO {
+        #[hdl(sim)]
+        IO::<_> {
             en: false,
-            which_in: 0,
-            data_in: 0,
-            which_out: 1,
-            data_out: 0,
-            b_out: HdlSome((0_hdl_u1, false)),
+            which_in: 0_hdl_u2,
+            data_in: 0_hdl_u4,
+            which_out: 1_hdl_u2,
+            data_out: 0_hdl_u4,
+            b_out: #[hdl(sim)]
+            (io_ty.b_out).HdlSome((0u8.cast_to(UInt[1]), false)),
+            b2_out: #[hdl(sim)]
+            HdlSome((0_hdl_u1, false)),
         },
-        IO {
+        #[hdl(sim)]
+        IO::<_> {
             en: true,
-            which_in: 1,
-            data_in: 0xF,
-            which_out: 1,
-            data_out: 0,
-            b_out: HdlSome((0_hdl_u1, false)),
+            which_in: 1_hdl_u2,
+            data_in: 0xF_hdl_u4,
+            which_out: 1_hdl_u2,
+            data_out: 0_hdl_u4,
+            b_out: #[hdl(sim)]
+            (io_ty.b_out).HdlSome((0u8.cast_to(UInt[1]), false)),
+            b2_out: #[hdl(sim)]
+            HdlSome((0_hdl_u1, false)),
         },
-        IO {
+        #[hdl(sim)]
+        IO::<_> {
             en: true,
-            which_in: 1,
-            data_in: 0xF,
-            which_out: 1,
-            data_out: 0x3,
-            b_out: HdlSome((1_hdl_u1, true)),
+            which_in: 1_hdl_u2,
+            data_in: 0xF_hdl_u4,
+            which_out: 1_hdl_u2,
+            data_out: 0x3_hdl_u4,
+            b_out: #[hdl(sim)]
+            (io_ty.b_out).HdlSome((1u8.cast_to(UInt[1]), true)),
+            b2_out: #[hdl(sim)]
+            HdlSome((1_hdl_u1, true)),
         },
-        IO {
+        #[hdl(sim)]
+        IO::<_> {
             en: true,
-            which_in: 2,
-            data_in: 0xF,
-            which_out: 1,
-            data_out: 0x3,
-            b_out: HdlSome((1_hdl_u1, true)),
+            which_in: 2_hdl_u2,
+            data_in: 0xF_hdl_u4,
+            which_out: 1_hdl_u2,
+            data_out: 0x3_hdl_u4,
+            b_out: #[hdl(sim)]
+            (io_ty.b_out).HdlSome((1u8.cast_to(UInt[1]), true)),
+            b2_out: #[hdl(sim)]
+            HdlSome((1_hdl_u1, true)),
         },
-        IO {
+        #[hdl(sim)]
+        IO::<_> {
             en: true,
-            which_in: 2,
-            data_in: 0xF,
-            which_out: 2,
-            data_out: 0xF,
-            b_out: HdlNone(),
+            which_in: 2_hdl_u2,
+            data_in: 0xF_hdl_u4,
+            which_out: 2_hdl_u2,
+            data_out: 0xF_hdl_u4,
+            b_out: #[hdl(sim)]
+            (io_ty.b_out).HdlNone(),
+            b2_out: #[hdl(sim)]
+            HdlNone(),
         },
     ];
-    for (
-        cycle,
-        expected @ IO {
+    for (cycle, expected) in io_cycles.into_iter().enumerate() {
+        #[hdl(sim)]
+        let IO::<_> {
             en,
             which_in,
             data_in,
             which_out: _,
             data_out: _,
             b_out: _,
-        },
-    ) in io_cycles.into_iter().enumerate()
-    {
-        sim.write_bool(sim.io().en, en);
-        sim.write_bool_or_int(sim.io().which_in, which_in.cast_to_static());
-        sim.write_bool_or_int(sim.io().data_in, data_in.cast_to_static());
-        let io = IO {
+            b2_out: _,
+        } = expected;
+        sim.write(sim.io().en, &en);
+        sim.write(sim.io().which_in, &which_in);
+        sim.write(sim.io().data_in, &data_in);
+        let io = #[hdl(sim)]
+        IO::<_> {
             en,
             which_in,
             data_in,
-            which_out: sim
-                .read_bool_or_int(sim.io().which_out)
-                .to_bigint()
-                .try_into()
-                .expect("known to be in range"),
-            data_out: sim
-                .read_bool_or_int(sim.io().data_out)
-                .to_bigint()
-                .try_into()
-                .expect("known to be in range"),
-            b_out: sim.read(sim.io().b_out).to_expr(),
+            which_out: sim.read(sim.io().which_out),
+            data_out: sim.read(sim.io().data_out),
+            b_out: sim.read(sim.io().b_out),
+            b2_out: sim.read(sim.io().b2_out),
         };
         assert_eq!(
             expected,
@@ -517,6 +526,12 @@ fn test_enums() {
             "vcd:\n{}\ncycle: {cycle}",
             String::from_utf8(writer.take()).unwrap(),
         );
+        // make sure matching on SimValue<SomeEnum> works
+        #[hdl(sim)]
+        match io.b_out {
+            HdlNone => println!("io.b_out is HdlNone"),
+            HdlSome(v) => println!("io.b_out is HdlSome(({:?}, {:?}))", *v.0, *v.1),
+        }
         sim.write_clock(sim.io().cd.clk, false);
         sim.advance_time(SimDuration::from_micros(1));
         sim.write_clock(sim.io().cd.clk, true);
@@ -538,9 +553,9 @@ fn test_enums() {
 #[hdl_module(outline_generated)]
 pub fn memories() {
     #[hdl]
-    let r: fayalite::memory::ReadStruct<(UInt<8>, SInt<8>), ConstUsize<4>> = m.input();
+    let r: ReadStruct<(UInt<8>, SInt<8>), ConstUsize<4>> = m.input();
     #[hdl]
-    let w: fayalite::memory::WriteStruct<(UInt<8>, SInt<8>), ConstUsize<4>> = m.input();
+    let w: WriteStruct<(UInt<8>, SInt<8>), ConstUsize<4>> = m.input();
     #[hdl]
     let mut mem = memory_with_init([(0x01u8, 0x23i8); 16]);
     mem.read_latency(0);
@@ -559,120 +574,131 @@ fn test_memories() {
     sim.add_trace_writer(VcdWriterDecls::new(writer.clone()));
     sim.write_clock(sim.io().r.clk, false);
     sim.write_clock(sim.io().w.clk, false);
-    #[derive(Debug, PartialEq, Eq)]
+    #[hdl(cmp_eq)]
     struct IO {
-        r_addr: u8,
-        r_en: bool,
-        r_data: (u8, i8),
-        w_addr: u8,
-        w_en: bool,
-        w_data: (u8, i8),
-        w_mask: (bool, bool),
+        r_addr: UInt<4>,
+        r_en: Bool,
+        r_data: (UInt<8>, SInt<8>),
+        w_addr: UInt<4>,
+        w_en: Bool,
+        w_data: (UInt<8>, SInt<8>),
+        w_mask: (Bool, Bool),
     }
     let io_cycles = [
+        #[hdl(sim)]
         IO {
-            r_addr: 0,
+            r_addr: 0_hdl_u4,
             r_en: false,
-            r_data: (0, 0),
-            w_addr: 0,
+            r_data: (0u8, 0i8),
+            w_addr: 0_hdl_u4,
             w_en: false,
-            w_data: (0, 0),
+            w_data: (0u8, 0i8),
             w_mask: (false, false),
         },
+        #[hdl(sim)]
         IO {
-            r_addr: 0,
+            r_addr: 0_hdl_u4,
             r_en: true,
-            r_data: (0x1, 0x23),
-            w_addr: 0,
+            r_data: (0x1u8, 0x23i8),
+            w_addr: 0_hdl_u4,
             w_en: true,
-            w_data: (0x10, 0x20),
+            w_data: (0x10u8, 0x20i8),
             w_mask: (true, true),
         },
+        #[hdl(sim)]
         IO {
-            r_addr: 0,
+            r_addr: 0_hdl_u4,
             r_en: true,
-            r_data: (0x10, 0x20),
-            w_addr: 0,
+            r_data: (0x10u8, 0x20i8),
+            w_addr: 0_hdl_u4,
             w_en: true,
-            w_data: (0x30, 0x40),
+            w_data: (0x30u8, 0x40i8),
             w_mask: (false, true),
         },
+        #[hdl(sim)]
         IO {
-            r_addr: 0,
+            r_addr: 0_hdl_u4,
             r_en: true,
-            r_data: (0x10, 0x40),
-            w_addr: 0,
+            r_data: (0x10u8, 0x40i8),
+            w_addr: 0_hdl_u4,
             w_en: true,
-            w_data: (0x50, 0x60),
+            w_data: (0x50u8, 0x60i8),
             w_mask: (true, false),
         },
+        #[hdl(sim)]
         IO {
-            r_addr: 0,
+            r_addr: 0_hdl_u4,
             r_en: true,
-            r_data: (0x50, 0x40),
-            w_addr: 0,
+            r_data: (0x50u8, 0x40i8),
+            w_addr: 0_hdl_u4,
             w_en: true,
-            w_data: (0x70, -0x80),
+            w_data: (0x70u8, -0x80i8),
             w_mask: (false, false),
         },
+        #[hdl(sim)]
         IO {
-            r_addr: 0,
+            r_addr: 0_hdl_u4,
             r_en: true,
-            r_data: (0x50, 0x40),
-            w_addr: 0,
+            r_data: (0x50u8, 0x40i8),
+            w_addr: 0_hdl_u4,
             w_en: false,
-            w_data: (0x90, 0xA0u8 as i8),
+            w_data: (0x90u8, 0xA0u8 as i8),
             w_mask: (false, false),
         },
+        #[hdl(sim)]
         IO {
-            r_addr: 0,
+            r_addr: 0_hdl_u4,
             r_en: true,
-            r_data: (0x50, 0x40),
-            w_addr: 1,
+            r_data: (0x50u8, 0x40i8),
+            w_addr: 1_hdl_u4,
             w_en: true,
-            w_data: (0x90, 0xA0u8 as i8),
+            w_data: (0x90u8, 0xA0u8 as i8),
             w_mask: (true, true),
         },
+        #[hdl(sim)]
         IO {
-            r_addr: 0,
+            r_addr: 0_hdl_u4,
             r_en: true,
-            r_data: (0x50, 0x40),
-            w_addr: 2,
+            r_data: (0x50u8, 0x40i8),
+            w_addr: 2_hdl_u4,
             w_en: true,
-            w_data: (0xB0, 0xC0u8 as i8),
+            w_data: (0xB0u8, 0xC0u8 as i8),
             w_mask: (true, true),
         },
+        #[hdl(sim)]
         IO {
-            r_addr: 0,
+            r_addr: 0_hdl_u4,
             r_en: true,
-            r_data: (0x50, 0x40),
-            w_addr: 2,
+            r_data: (0x50u8, 0x40i8),
+            w_addr: 2_hdl_u4,
             w_en: false,
-            w_data: (0xD0, 0xE0u8 as i8),
+            w_data: (0xD0u8, 0xE0u8 as i8),
             w_mask: (true, true),
         },
+        #[hdl(sim)]
         IO {
-            r_addr: 1,
+            r_addr: 1_hdl_u4,
             r_en: true,
-            r_data: (0x90, 0xA0u8 as i8),
-            w_addr: 2,
+            r_data: (0x90u8, 0xA0u8 as i8),
+            w_addr: 2_hdl_u4,
             w_en: false,
-            w_data: (0xD0, 0xE0u8 as i8),
+            w_data: (0xD0u8, 0xE0u8 as i8),
             w_mask: (true, true),
         },
+        #[hdl(sim)]
         IO {
-            r_addr: 2,
+            r_addr: 2_hdl_u4,
             r_en: true,
-            r_data: (0xB0, 0xC0u8 as i8),
-            w_addr: 2,
+            r_data: (0xB0u8, 0xC0u8 as i8),
+            w_addr: 2_hdl_u4,
             w_en: false,
-            w_data: (0xD0, 0xE0u8 as i8),
+            w_data: (0xD0u8, 0xE0u8 as i8),
             w_mask: (true, true),
         },
     ];
-    for (
-        cycle,
-        expected @ IO {
+    for (cycle, expected) in io_cycles.into_iter().enumerate() {
+        #[hdl(sim)]
+        let IO {
             r_addr,
             r_en,
             r_data: _,
@@ -680,30 +706,18 @@ fn test_memories() {
             w_en,
             w_data,
             w_mask,
-        },
-    ) in io_cycles.into_iter().enumerate()
-    {
-        sim.write_bool_or_int(sim.io().r.addr, r_addr.cast_to_static());
-        sim.write_bool(sim.io().r.en, r_en);
-        sim.write_bool_or_int(sim.io().w.addr, w_addr.cast_to_static());
-        sim.write_bool(sim.io().w.en, w_en);
-        sim.write_bool_or_int(sim.io().w.data.0, w_data.0);
-        sim.write_bool_or_int(sim.io().w.data.1, w_data.1);
-        sim.write_bool(sim.io().w.mask.0, w_mask.0);
-        sim.write_bool(sim.io().w.mask.1, w_mask.1);
-        let io = IO {
+        } = expected;
+        sim.write(sim.io().r.addr, &r_addr);
+        sim.write(sim.io().r.en, &r_en);
+        sim.write(sim.io().w.addr, &w_addr);
+        sim.write(sim.io().w.en, &w_en);
+        sim.write(sim.io().w.data, &w_data);
+        sim.write(sim.io().w.mask, &w_mask);
+        let io = #[hdl(sim)]
+        IO {
             r_addr,
             r_en,
-            r_data: (
-                sim.read_bool_or_int(sim.io().r.data.0)
-                    .to_bigint()
-                    .try_into()
-                    .expect("known to be in range"),
-                sim.read_bool_or_int(sim.io().r.data.1)
-                    .to_bigint()
-                    .try_into()
-                    .expect("known to be in range"),
-            ),
+            r_data: sim.read(sim.io().r.data),
             w_addr,
             w_en,
             w_data,
@@ -716,11 +730,11 @@ fn test_memories() {
             String::from_utf8(writer.take()).unwrap(),
         );
         sim.advance_time(SimDuration::from_micros(1));
-        sim.write_clock(sim.io().r.clk, true);
-        sim.write_clock(sim.io().w.clk, true);
+        sim.write(sim.io().r.clk, true);
+        sim.write(sim.io().w.clk, true);
         sim.advance_time(SimDuration::from_micros(1));
-        sim.write_clock(sim.io().r.clk, false);
-        sim.write_clock(sim.io().w.clk, false);
+        sim.write(sim.io().r.clk, false);
+        sim.write(sim.io().w.clk, false);
     }
     sim.flush_traces().unwrap();
     let vcd = String::from_utf8(writer.take()).unwrap();
@@ -738,7 +752,7 @@ fn test_memories() {
 #[hdl_module(outline_generated)]
 pub fn memories2() {
     #[hdl]
-    let rw: fayalite::memory::ReadWriteStruct<UInt<2>, ConstUsize<3>> = m.input();
+    let rw: ReadWriteStruct<UInt<2>, ConstUsize<3>> = m.input();
     #[hdl]
     let mut mem = memory_with_init([HdlSome(true); 5]);
     mem.read_latency(1);
@@ -1011,9 +1025,9 @@ fn test_memories2() {
 #[hdl_module(outline_generated)]
 pub fn memories3() {
     #[hdl]
-    let r: fayalite::memory::ReadStruct<Array<UInt<8>, 8>, ConstUsize<3>> = m.input();
+    let r: ReadStruct<Array<UInt<8>, 8>, ConstUsize<3>> = m.input();
     #[hdl]
-    let w: fayalite::memory::WriteStruct<Array<UInt<8>, 8>, ConstUsize<3>> = m.input();
+    let w: WriteStruct<Array<UInt<8>, 8>, ConstUsize<3>> = m.input();
     #[hdl]
     let mut mem: MemBuilder<Array<UInt<8>, 8>> = memory();
     mem.depth(8);
@@ -1443,3 +1457,172 @@ fn test_conditional_assignment_last() {
         panic!();
     }
 }
+
+#[hdl_module(outline_generated, extern)]
+pub fn extern_module() {
+    #[hdl]
+    let i: Bool = m.input();
+    #[hdl]
+    let o: Bool = m.output();
+    m.extern_module_simulation_fn((i, o), |(i, o), mut sim| async move {
+        sim.write(o, true).await;
+        sim.advance_time(SimDuration::from_nanos(500)).await;
+        let mut invert = false;
+        loop {
+            sim.advance_time(SimDuration::from_micros(1)).await;
+            let v = sim.read_bool(i).await;
+            sim.write(o, v ^ invert).await;
+            invert = !invert;
+        }
+    });
+}
+
+#[test]
+fn test_extern_module() {
+    let _n = SourceLocation::normalize_files_for_tests();
+    let mut sim = Simulation::new(extern_module());
+    let mut writer = RcWriter::default();
+    sim.add_trace_writer(VcdWriterDecls::new(writer.clone()));
+    sim.write(sim.io().i, false);
+    sim.advance_time(SimDuration::from_micros(10));
+    sim.write(sim.io().i, true);
+    sim.advance_time(SimDuration::from_micros(10));
+    sim.flush_traces().unwrap();
+    let vcd = String::from_utf8(writer.take()).unwrap();
+    println!("####### VCD:\n{vcd}\n#######");
+    if vcd != include_str!("sim/expected/extern_module.vcd") {
+        panic!();
+    }
+    let sim_debug = format!("{sim:#?}");
+    println!("#######\n{sim_debug}\n#######");
+    if sim_debug != include_str!("sim/expected/extern_module.txt") {
+        panic!();
+    }
+}
+
+#[hdl_module(outline_generated, extern)]
+pub fn extern_module2() {
+    #[hdl]
+    let en: Bool = m.input();
+    #[hdl]
+    let clk: Clock = m.input();
+    #[hdl]
+    let o: UInt<8> = m.output();
+    m.extern_module_simulation_fn((en, clk, o), |(en, clk, o), mut sim| async move {
+        for b in "Hello, World!\n".bytes().cycle() {
+            sim.write(o, b).await;
+            loop {
+                sim.wait_for_clock_edge(clk).await;
+                if sim.read_bool(en).await {
+                    break;
+                }
+            }
+        }
+    });
+}
+
+#[test]
+fn test_extern_module2() {
+    let _n = SourceLocation::normalize_files_for_tests();
+    let mut sim = Simulation::new(extern_module2());
+    let mut writer = RcWriter::default();
+    sim.add_trace_writer(VcdWriterDecls::new(writer.clone()));
+    for i in 0..30 {
+        sim.write(sim.io().en, i % 10 < 5);
+        sim.write(sim.io().clk, false);
+        sim.advance_time(SimDuration::from_micros(1));
+        sim.write(sim.io().clk, true);
+        sim.advance_time(SimDuration::from_micros(1));
+    }
+    sim.flush_traces().unwrap();
+    let vcd = String::from_utf8(writer.take()).unwrap();
+    println!("####### VCD:\n{vcd}\n#######");
+    if vcd != include_str!("sim/expected/extern_module2.vcd") {
+        panic!();
+    }
+    let sim_debug = format!("{sim:#?}");
+    println!("#######\n{sim_debug}\n#######");
+    if sim_debug != include_str!("sim/expected/extern_module2.txt") {
+        panic!();
+    }
+}
+
+// use an extern module to simulate a register to test that the
+// simulator can handle chains of alternating circuits and extern modules.
+#[hdl_module(outline_generated, extern)]
+pub fn sw_reg() {
+    #[hdl]
+    let clk: Clock = m.input();
+    #[hdl]
+    let o: Bool = m.output();
+    m.extern_module_simulation_fn((clk, o), |(clk, o), mut sim| async move {
+        let mut state = false;
+        loop {
+            sim.write(o, state).await;
+            sim.wait_for_clock_edge(clk).await;
+            state = !state;
+        }
+    });
+}
+
+#[hdl_module(outline_generated)]
+pub fn ripple_counter() {
+    #[hdl]
+    let clk: Clock = m.input();
+    #[hdl]
+    let o: UInt<6> = m.output();
+
+    #[hdl]
+    let bits: Array<Bool, 6> = wire();
+
+    connect_any(o, bits.cast_to_bits());
+
+    let mut clk_in = clk;
+    for (i, bit) in bits.into_iter().enumerate() {
+        if i % 2 == 0 {
+            let bit_reg = reg_builder_with_loc(&format!("bit_reg_{i}"), SourceLocation::caller())
+                .clock_domain(
+                    #[hdl]
+                    ClockDomain {
+                        clk: clk_in,
+                        rst: false.to_sync_reset(),
+                    },
+                )
+                .no_reset(Bool)
+                .build();
+            connect(bit, bit_reg);
+            connect(bit_reg, !bit_reg);
+        } else {
+            let bit_reg =
+                instance_with_loc(&format!("bit_reg_{i}"), sw_reg(), SourceLocation::caller());
+            connect(bit_reg.clk, clk_in);
+            connect(bit, bit_reg.o);
+        }
+        clk_in = bit.to_clock();
+    }
+}
+
+#[test]
+fn test_ripple_counter() {
+    let _n = SourceLocation::normalize_files_for_tests();
+    let mut sim = Simulation::new(ripple_counter());
+    let mut writer = RcWriter::default();
+    sim.add_trace_writer(VcdWriterDecls::new(writer.clone()));
+    for _ in 0..0x80 {
+        sim.write(sim.io().clk, false);
+        sim.advance_time(SimDuration::from_micros(1));
+        sim.write(sim.io().clk, true);
+        sim.advance_time(SimDuration::from_micros(1));
+    }
+    sim.flush_traces().unwrap();
+    let vcd = String::from_utf8(writer.take()).unwrap();
+    println!("####### VCD:\n{vcd}\n#######");
+    if vcd != include_str!("sim/expected/ripple_counter.vcd") {
+        panic!();
+    }
+    let sim_debug = format!("{sim:#?}");
+    println!("#######\n{sim_debug}\n#######");
+    if sim_debug != include_str!("sim/expected/ripple_counter.txt") {
+        panic!();
+    }
+}

crates/fayalite/tests/sim/expected/conditional_assignment_last.txt

@@ -92,7 +92,17 @@ Simulation {
             ..
         },
     },
-    uninitialized_inputs: {},
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::conditional_assignment_last,
+                instantiated: Module {
+                    name: conditional_assignment_last,
+                    ..
+                },
+            }.i,
+        ],
+        uninitialized_ios: {},
         io_targets: {
             Instance {
                 name: <simulator>::conditional_assignment_last,
@@ -100,37 +110,12 @@ Simulation {
                     name: conditional_assignment_last,
                     ..
                 },
-        }.i: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bool,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
+            }.i,
         },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(conditional_assignment_last: conditional_assignment_last).conditional_assignment_last::i",
-                                ty: Bool,
+        did_initial_settle: true,
     },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 1 },
-            },
-            write: None,
-        },
-    },
-    made_initial_step: true,
-    needs_settle: false,
+    extern_modules: [],
+    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "conditional_assignment_last",
         children: [

crates/fayalite/tests/sim/expected/connect_const.txt

@@ -68,7 +68,17 @@ Simulation {
             ..
         },
     },
-    uninitialized_inputs: {},
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::connect_const,
+                instantiated: Module {
+                    name: connect_const,
+                    ..
+                },
+            }.o,
+        ],
+        uninitialized_ios: {},
         io_targets: {
             Instance {
                 name: <simulator>::connect_const,
@@ -76,37 +86,12 @@ Simulation {
                     name: connect_const,
                     ..
                 },
-        }.o: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: UInt<8>,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
+            }.o,
         },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(connect_const: connect_const).connect_const::o",
-                                ty: UInt<8>,
+        did_initial_settle: true,
     },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 1 },
-            },
-            write: None,
-        },
-    },
-    made_initial_step: true,
-    needs_settle: false,
+    extern_modules: [],
+    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "connect_const",
         children: [

crates/fayalite/tests/sim/expected/connect_const_reset.txt

@@ -97,7 +97,24 @@ Simulation {
             ..
         },
     },
-    uninitialized_inputs: {},
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::connect_const_reset,
+                instantiated: Module {
+                    name: connect_const_reset,
+                    ..
+                },
+            }.reset_out,
+            Instance {
+                name: <simulator>::connect_const_reset,
+                instantiated: Module {
+                    name: connect_const_reset,
+                    ..
+                },
+            }.bit_out,
+        ],
+        uninitialized_ios: {},
         io_targets: {
             Instance {
                 name: <simulator>::connect_const_reset,
@@ -105,71 +122,19 @@ Simulation {
                     name: connect_const_reset,
                     ..
                 },
-        }.bit_out: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bool,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(connect_const_reset: connect_const_reset).connect_const_reset::bit_out",
-                                ty: Bool,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 1, len: 1 },
-            },
-            write: None,
-        },
+            }.bit_out,
             Instance {
                 name: <simulator>::connect_const_reset,
                 instantiated: Module {
                     name: connect_const_reset,
                     ..
                 },
-        }.reset_out: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: AsyncReset,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
+            }.reset_out,
         },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(connect_const_reset: connect_const_reset).connect_const_reset::reset_out",
-                                ty: AsyncReset,
+        did_initial_settle: true,
     },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 1 },
-            },
-            write: None,
-        },
-    },
-    made_initial_step: true,
-    needs_settle: false,
+    extern_modules: [],
+    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "connect_const_reset",
         children: [

crates/fayalite/tests/sim/expected/counter_async.txt

@@ -203,7 +203,24 @@ Simulation {
             ..
         },
     },
-    uninitialized_inputs: {},
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::counter,
+                instantiated: Module {
+                    name: counter,
+                    ..
+                },
+            }.cd,
+            Instance {
+                name: <simulator>::counter,
+                instantiated: Module {
+                    name: counter,
+                    ..
+                },
+            }.count,
+        ],
+        uninitialized_ios: {},
         io_targets: {
             Instance {
                 name: <simulator>::counter,
@@ -211,205 +228,33 @@ Simulation {
                     name: counter,
                     ..
                 },
-        }.cd: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bundle {
-                    /* offset = 0 */
-                    clk: Clock,
-                    /* offset = 1 */
-                    rst: AsyncReset,
-                },
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 2,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(counter: counter).counter::cd.clk",
-                                ty: Clock,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(counter: counter).counter::cd.rst",
-                                ty: AsyncReset,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Bundle {
-                    fields: [
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(0),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: Clock,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: Clock,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(1),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: AsyncReset,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: AsyncReset,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                    ],
-                },
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 2 },
-            },
-            write: None,
-        },
+            }.cd,
             Instance {
                 name: <simulator>::counter,
                 instantiated: Module {
                     name: counter,
                     ..
                 },
-        }.cd.clk: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Clock,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: Clock,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 1 },
-            },
-            write: None,
-        },
+            }.cd.clk,
             Instance {
                 name: <simulator>::counter,
                 instantiated: Module {
                     name: counter,
                     ..
                 },
-        }.cd.rst: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: AsyncReset,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: AsyncReset,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 1, len: 1 },
-            },
-            write: None,
-        },
+            }.cd.rst,
             Instance {
                 name: <simulator>::counter,
                 instantiated: Module {
                     name: counter,
                     ..
                 },
-        }.count: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: UInt<4>,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
+            }.count,
         },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(counter: counter).counter::count",
-                                ty: UInt<4>,
+        did_initial_settle: true,
     },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 2, len: 1 },
-            },
-            write: None,
-        },
-    },
-    made_initial_step: true,
-    needs_settle: false,
+    extern_modules: [],
+    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "counter",
         children: [

crates/fayalite/tests/sim/expected/counter_sync.txt

@@ -184,7 +184,24 @@ Simulation {
             ..
         },
     },
-    uninitialized_inputs: {},
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::counter,
+                instantiated: Module {
+                    name: counter,
+                    ..
+                },
+            }.cd,
+            Instance {
+                name: <simulator>::counter,
+                instantiated: Module {
+                    name: counter,
+                    ..
+                },
+            }.count,
+        ],
+        uninitialized_ios: {},
         io_targets: {
             Instance {
                 name: <simulator>::counter,
@@ -192,205 +209,33 @@ Simulation {
                     name: counter,
                     ..
                 },
-        }.cd: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bundle {
-                    /* offset = 0 */
-                    clk: Clock,
-                    /* offset = 1 */
-                    rst: SyncReset,
-                },
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 2,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(counter: counter).counter::cd.clk",
-                                ty: Clock,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(counter: counter).counter::cd.rst",
-                                ty: SyncReset,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Bundle {
-                    fields: [
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(0),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: Clock,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: Clock,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(1),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: SyncReset,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: SyncReset,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                    ],
-                },
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 2 },
-            },
-            write: None,
-        },
+            }.cd,
             Instance {
                 name: <simulator>::counter,
                 instantiated: Module {
                     name: counter,
                     ..
                 },
-        }.cd.clk: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Clock,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: Clock,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 1 },
-            },
-            write: None,
-        },
+            }.cd.clk,
             Instance {
                 name: <simulator>::counter,
                 instantiated: Module {
                     name: counter,
                     ..
                 },
-        }.cd.rst: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: SyncReset,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: SyncReset,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 1, len: 1 },
-            },
-            write: None,
-        },
+            }.cd.rst,
             Instance {
                 name: <simulator>::counter,
                 instantiated: Module {
                     name: counter,
                     ..
                 },
-        }.count: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: UInt<4>,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
+            }.count,
         },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(counter: counter).counter::count",
-                                ty: UInt<4>,
+        did_initial_settle: true,
     },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 2, len: 1 },
-            },
-            write: None,
-        },
-    },
-    made_initial_step: true,
-    needs_settle: false,
+    extern_modules: [],
+    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "counter",
         children: [

crates/fayalite/tests/sim/expected/duplicate_names.txt

@@ -88,10 +88,14 @@ Simulation {
             ..
         },
     },
-    uninitialized_inputs: {},
+    main_module: SimulationModuleState {
+        base_targets: [],
+        uninitialized_ios: {},
         io_targets: {},
-    made_initial_step: true,
-    needs_settle: false,
+        did_initial_settle: true,
+    },
+    extern_modules: [],
+    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "duplicate_names",
         children: [

crates/fayalite/tests/sim/expected/enums.vcd

@@ -16,18 +16,25 @@ $var wire 1 ) \0 $end
 $var wire 1 * \1 $end
 $upscope $end
 $upscope $end
-$scope struct the_reg $end
+$scope struct b2_out $end
 $var string 1 + \$tag $end
+$scope struct HdlSome $end
+$var wire 1 , \0 $end
+$var wire 1 - \1 $end
+$upscope $end
+$upscope $end
+$scope struct the_reg $end
+$var string 1 . \$tag $end
 $scope struct B $end
-$var reg 1 , \0 $end
-$var reg 1 - \1 $end
+$var reg 1 / \0 $end
+$var reg 1 0 \1 $end
 $upscope $end
 $scope struct C $end
 $scope struct a $end
-$var reg 1 . \[0] $end
-$var reg 1 / \[1] $end
+$var reg 1 1 \[0] $end
+$var reg 1 2 \[1] $end
 $upscope $end
-$var reg 2 0 b $end
+$var reg 2 3 b $end
 $upscope $end
 $upscope $end
 $upscope $end
@@ -43,12 +50,15 @@ b0 '
 sHdlNone\x20(0) (
 0)
 0*
-sA\x20(0) +
+sHdlNone\x20(0) +
 0,
 0-
-0.
+sA\x20(0) .
 0/
-b0 0
+00
+01
+02
+b0 3
 $end
 #1000000
 1!
@@ -66,7 +76,8 @@ b1 $
 1!
 b1 &
 sHdlSome\x20(1) (
-sB\x20(1) +
+sHdlSome\x20(1) +
+sB\x20(1) .
 #6000000
 0#
 b0 $
@@ -85,8 +96,10 @@ b11 '
 1*
 1,
 1-
-1.
 1/
+10
+11
+12
 #10000000
 0!
 #11000000
@@ -101,8 +114,11 @@ b1111 '
 sHdlNone\x20(0) (
 0)
 0*
-sC\x20(2) +
-b11 0
+sHdlNone\x20(0) +
+0,
+0-
+sC\x20(2) .
+b11 3
 #14000000
 0!
 #15000000

crates/fayalite/tests/sim/expected/extern_module.txt

@@ -0,0 +1,220 @@
+Simulation {
+    state: State {
+        insns: Insns {
+            state_layout: StateLayout {
+                ty: TypeLayout {
+                    small_slots: StatePartLayout<SmallSlots> {
+                        len: 0,
+                        debug_data: [],
+                        ..
+                    },
+                    big_slots: StatePartLayout<BigSlots> {
+                        len: 2,
+                        debug_data: [
+                            SlotDebugData {
+                                name: "InstantiatedModule(extern_module: extern_module).extern_module::i",
+                                ty: Bool,
+                            },
+                            SlotDebugData {
+                                name: "InstantiatedModule(extern_module: extern_module).extern_module::o",
+                                ty: Bool,
+                            },
+                        ],
+                        ..
+                    },
+                },
+                memories: StatePartLayout<Memories> {
+                    len: 0,
+                    debug_data: [],
+                    layout_data: [],
+                    ..
+                },
+            },
+            insns: [
+                // at: module-XXXXXXXXXX.rs:1:1
+                0: Return,
+            ],
+            ..
+        },
+        pc: 0,
+        memory_write_log: [],
+        memories: StatePart {
+            value: [],
+        },
+        small_slots: StatePart {
+            value: [],
+        },
+        big_slots: StatePart {
+            value: [
+                1,
+                1,
+            ],
+        },
+    },
+    io: Instance {
+        name: <simulator>::extern_module,
+        instantiated: Module {
+            name: extern_module,
+            ..
+        },
+    },
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::extern_module,
+                instantiated: Module {
+                    name: extern_module,
+                    ..
+                },
+            }.i,
+            Instance {
+                name: <simulator>::extern_module,
+                instantiated: Module {
+                    name: extern_module,
+                    ..
+                },
+            }.o,
+        ],
+        uninitialized_ios: {},
+        io_targets: {
+            Instance {
+                name: <simulator>::extern_module,
+                instantiated: Module {
+                    name: extern_module,
+                    ..
+                },
+            }.i,
+            Instance {
+                name: <simulator>::extern_module,
+                instantiated: Module {
+                    name: extern_module,
+                    ..
+                },
+            }.o,
+        },
+        did_initial_settle: true,
+    },
+    extern_modules: [
+        SimulationExternModuleState {
+            module_state: SimulationModuleState {
+                base_targets: [
+                    ModuleIO {
+                        name: extern_module::i,
+                        is_input: true,
+                        ty: Bool,
+                        ..
+                    },
+                    ModuleIO {
+                        name: extern_module::o,
+                        is_input: false,
+                        ty: Bool,
+                        ..
+                    },
+                ],
+                uninitialized_ios: {},
+                io_targets: {
+                    ModuleIO {
+                        name: extern_module::i,
+                        is_input: true,
+                        ty: Bool,
+                        ..
+                    },
+                    ModuleIO {
+                        name: extern_module::o,
+                        is_input: false,
+                        ty: Bool,
+                        ..
+                    },
+                },
+                did_initial_settle: true,
+            },
+            sim: ExternModuleSimulation {
+                generator: SimGeneratorFn {
+                    args: (
+                        ModuleIO {
+                            name: extern_module::i,
+                            is_input: true,
+                            ty: Bool,
+                            ..
+                        },
+                        ModuleIO {
+                            name: extern_module::o,
+                            is_input: false,
+                            ty: Bool,
+                            ..
+                        },
+                    ),
+                    f: ...,
+                },
+                source_location: SourceLocation(
+                    module-XXXXXXXXXX.rs:4:1,
+                ),
+            },
+            running_generator: Some(
+                ...,
+            ),
+            wait_targets: {
+                Instant(
+                    20.500000000000 μs,
+                ),
+            },
+        },
+    ],
+    state_ready_to_run: false,
+    trace_decls: TraceModule {
+        name: "extern_module",
+        children: [
+            TraceModuleIO {
+                name: "i",
+                child: TraceBool {
+                    location: TraceScalarId(0),
+                    name: "i",
+                    flow: Source,
+                },
+                ty: Bool,
+                flow: Source,
+            },
+            TraceModuleIO {
+                name: "o",
+                child: TraceBool {
+                    location: TraceScalarId(1),
+                    name: "o",
+                    flow: Sink,
+                },
+                ty: Bool,
+                flow: Sink,
+            },
+        ],
+    },
+    traces: [
+        SimTrace {
+            id: TraceScalarId(0),
+            kind: BigBool {
+                index: StatePartIndex<BigSlots>(0),
+            },
+            state: 0x1,
+            last_state: 0x1,
+        },
+        SimTrace {
+            id: TraceScalarId(1),
+            kind: BigBool {
+                index: StatePartIndex<BigSlots>(1),
+            },
+            state: 0x1,
+            last_state: 0x1,
+        },
+    ],
+    trace_memories: {},
+    trace_writers: [
+        Running(
+            VcdWriter {
+                finished_init: true,
+                timescale: 1 ps,
+                ..
+            },
+        ),
+    ],
+    instant: 20 μs,
+    clocks_triggered: [],
+    ..
+}

crates/fayalite/tests/sim/expected/extern_module.vcd

@@ -0,0 +1,51 @@
+$timescale 1 ps $end
+$scope module extern_module $end
+$var wire 1 ! i $end
+$var wire 1 " o $end
+$upscope $end
+$enddefinitions $end
+$dumpvars
+0!
+1"
+$end
+#500000
+#1500000
+0"
+#2500000
+1"
+#3500000
+0"
+#4500000
+1"
+#5500000
+0"
+#6500000
+1"
+#7500000
+0"
+#8500000
+1"
+#9500000
+0"
+#10000000
+1!
+#10500000
+#11500000
+1"
+#12500000
+0"
+#13500000
+1"
+#14500000
+0"
+#15500000
+1"
+#16500000
+0"
+#17500000
+1"
+#18500000
+0"
+#19500000
+1"
+#20000000

crates/fayalite/tests/sim/expected/extern_module2.txt

@@ -0,0 +1,310 @@
+Simulation {
+    state: State {
+        insns: Insns {
+            state_layout: StateLayout {
+                ty: TypeLayout {
+                    small_slots: StatePartLayout<SmallSlots> {
+                        len: 0,
+                        debug_data: [],
+                        ..
+                    },
+                    big_slots: StatePartLayout<BigSlots> {
+                        len: 3,
+                        debug_data: [
+                            SlotDebugData {
+                                name: "InstantiatedModule(extern_module2: extern_module2).extern_module2::en",
+                                ty: Bool,
+                            },
+                            SlotDebugData {
+                                name: "InstantiatedModule(extern_module2: extern_module2).extern_module2::clk",
+                                ty: Clock,
+                            },
+                            SlotDebugData {
+                                name: "InstantiatedModule(extern_module2: extern_module2).extern_module2::o",
+                                ty: UInt<8>,
+                            },
+                        ],
+                        ..
+                    },
+                },
+                memories: StatePartLayout<Memories> {
+                    len: 0,
+                    debug_data: [],
+                    layout_data: [],
+                    ..
+                },
+            },
+            insns: [
+                // at: module-XXXXXXXXXX.rs:1:1
+                0: Return,
+            ],
+            ..
+        },
+        pc: 0,
+        memory_write_log: [],
+        memories: StatePart {
+            value: [],
+        },
+        small_slots: StatePart {
+            value: [],
+        },
+        big_slots: StatePart {
+            value: [
+                0,
+                1,
+                101,
+            ],
+        },
+    },
+    io: Instance {
+        name: <simulator>::extern_module2,
+        instantiated: Module {
+            name: extern_module2,
+            ..
+        },
+    },
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::extern_module2,
+                instantiated: Module {
+                    name: extern_module2,
+                    ..
+                },
+            }.en,
+            Instance {
+                name: <simulator>::extern_module2,
+                instantiated: Module {
+                    name: extern_module2,
+                    ..
+                },
+            }.clk,
+            Instance {
+                name: <simulator>::extern_module2,
+                instantiated: Module {
+                    name: extern_module2,
+                    ..
+                },
+            }.o,
+        ],
+        uninitialized_ios: {},
+        io_targets: {
+            Instance {
+                name: <simulator>::extern_module2,
+                instantiated: Module {
+                    name: extern_module2,
+                    ..
+                },
+            }.clk,
+            Instance {
+                name: <simulator>::extern_module2,
+                instantiated: Module {
+                    name: extern_module2,
+                    ..
+                },
+            }.en,
+            Instance {
+                name: <simulator>::extern_module2,
+                instantiated: Module {
+                    name: extern_module2,
+                    ..
+                },
+            }.o,
+        },
+        did_initial_settle: true,
+    },
+    extern_modules: [
+        SimulationExternModuleState {
+            module_state: SimulationModuleState {
+                base_targets: [
+                    ModuleIO {
+                        name: extern_module2::en,
+                        is_input: true,
+                        ty: Bool,
+                        ..
+                    },
+                    ModuleIO {
+                        name: extern_module2::clk,
+                        is_input: true,
+                        ty: Clock,
+                        ..
+                    },
+                    ModuleIO {
+                        name: extern_module2::o,
+                        is_input: false,
+                        ty: UInt<8>,
+                        ..
+                    },
+                ],
+                uninitialized_ios: {},
+                io_targets: {
+                    ModuleIO {
+                        name: extern_module2::clk,
+                        is_input: true,
+                        ty: Clock,
+                        ..
+                    },
+                    ModuleIO {
+                        name: extern_module2::en,
+                        is_input: true,
+                        ty: Bool,
+                        ..
+                    },
+                    ModuleIO {
+                        name: extern_module2::o,
+                        is_input: false,
+                        ty: UInt<8>,
+                        ..
+                    },
+                },
+                did_initial_settle: true,
+            },
+            sim: ExternModuleSimulation {
+                generator: SimGeneratorFn {
+                    args: (
+                        ModuleIO {
+                            name: extern_module2::en,
+                            is_input: true,
+                            ty: Bool,
+                            ..
+                        },
+                        ModuleIO {
+                            name: extern_module2::clk,
+                            is_input: true,
+                            ty: Clock,
+                            ..
+                        },
+                        ModuleIO {
+                            name: extern_module2::o,
+                            is_input: false,
+                            ty: UInt<8>,
+                            ..
+                        },
+                    ),
+                    f: ...,
+                },
+                source_location: SourceLocation(
+                    module-XXXXXXXXXX.rs:5:1,
+                ),
+            },
+            running_generator: Some(
+                ...,
+            ),
+            wait_targets: {
+                Change {
+                    key: CompiledValue {
+                        layout: CompiledTypeLayout {
+                            ty: Clock,
+                            layout: TypeLayout {
+                                small_slots: StatePartLayout<SmallSlots> {
+                                    len: 0,
+                                    debug_data: [],
+                                    ..
+                                },
+                                big_slots: StatePartLayout<BigSlots> {
+                                    len: 1,
+                                    debug_data: [
+                                        SlotDebugData {
+                                            name: "InstantiatedModule(extern_module2: extern_module2).extern_module2::clk",
+                                            ty: Clock,
+                                        },
+                                    ],
+                                    ..
+                                },
+                            },
+                            body: Scalar,
+                        },
+                        range: TypeIndexRange {
+                            small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
+                            big_slots: StatePartIndexRange<BigSlots> { start: 1, len: 1 },
+                        },
+                        write: None,
+                    },
+                    value: SimValue {
+                        ty: Clock,
+                        value: OpaqueSimValue {
+                            bits: 0x1_u1,
+                        },
+                    },
+                },
+            },
+        },
+    ],
+    state_ready_to_run: false,
+    trace_decls: TraceModule {
+        name: "extern_module2",
+        children: [
+            TraceModuleIO {
+                name: "en",
+                child: TraceBool {
+                    location: TraceScalarId(0),
+                    name: "en",
+                    flow: Source,
+                },
+                ty: Bool,
+                flow: Source,
+            },
+            TraceModuleIO {
+                name: "clk",
+                child: TraceClock {
+                    location: TraceScalarId(1),
+                    name: "clk",
+                    flow: Source,
+                },
+                ty: Clock,
+                flow: Source,
+            },
+            TraceModuleIO {
+                name: "o",
+                child: TraceUInt {
+                    location: TraceScalarId(2),
+                    name: "o",
+                    ty: UInt<8>,
+                    flow: Sink,
+                },
+                ty: UInt<8>,
+                flow: Sink,
+            },
+        ],
+    },
+    traces: [
+        SimTrace {
+            id: TraceScalarId(0),
+            kind: BigBool {
+                index: StatePartIndex<BigSlots>(0),
+            },
+            state: 0x0,
+            last_state: 0x0,
+        },
+        SimTrace {
+            id: TraceScalarId(1),
+            kind: BigClock {
+                index: StatePartIndex<BigSlots>(1),
+            },
+            state: 0x1,
+            last_state: 0x1,
+        },
+        SimTrace {
+            id: TraceScalarId(2),
+            kind: BigUInt {
+                index: StatePartIndex<BigSlots>(2),
+                ty: UInt<8>,
+            },
+            state: 0x65,
+            last_state: 0x65,
+        },
+    ],
+    trace_memories: {},
+    trace_writers: [
+        Running(
+            VcdWriter {
+                finished_init: true,
+                timescale: 1 ps,
+                ..
+            },
+        ),
+    ],
+    instant: 60 μs,
+    clocks_triggered: [],
+    ..
+}

crates/fayalite/tests/sim/expected/extern_module2.vcd

@@ -0,0 +1,150 @@
+$timescale 1 ps $end
+$scope module extern_module2 $end
+$var wire 1 ! en $end
+$var wire 1 " clk $end
+$var wire 8 # o $end
+$upscope $end
+$enddefinitions $end
+$dumpvars
+1!
+0"
+b1001000 #
+$end
+#1000000
+1"
+b1100101 #
+#2000000
+0"
+#3000000
+1"
+b1101100 #
+#4000000
+0"
+#5000000
+1"
+#6000000
+0"
+#7000000
+1"
+b1101111 #
+#8000000
+0"
+#9000000
+1"
+b101100 #
+#10000000
+0!
+0"
+#11000000
+1"
+#12000000
+0"
+#13000000
+1"
+#14000000
+0"
+#15000000
+1"
+#16000000
+0"
+#17000000
+1"
+#18000000
+0"
+#19000000
+1"
+#20000000
+1!
+0"
+#21000000
+1"
+b100000 #
+#22000000
+0"
+#23000000
+1"
+b1010111 #
+#24000000
+0"
+#25000000
+1"
+b1101111 #
+#26000000
+0"
+#27000000
+1"
+b1110010 #
+#28000000
+0"
+#29000000
+1"
+b1101100 #
+#30000000
+0!
+0"
+#31000000
+1"
+#32000000
+0"
+#33000000
+1"
+#34000000
+0"
+#35000000
+1"
+#36000000
+0"
+#37000000
+1"
+#38000000
+0"
+#39000000
+1"
+#40000000
+1!
+0"
+#41000000
+1"
+b1100100 #
+#42000000
+0"
+#43000000
+1"
+b100001 #
+#44000000
+0"
+#45000000
+1"
+b1010 #
+#46000000
+0"
+#47000000
+1"
+b1001000 #
+#48000000
+0"
+#49000000
+1"
+b1100101 #
+#50000000
+0!
+0"
+#51000000
+1"
+#52000000
+0"
+#53000000
+1"
+#54000000
+0"
+#55000000
+1"
+#56000000
+0"
+#57000000
+1"
+#58000000
+0"
+#59000000
+1"
+#60000000

crates/fayalite/tests/sim/expected/memories2.txt

@@ -598,7 +598,17 @@ Simulation {
             ..
         },
     },
-    uninitialized_inputs: {},
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::memories2,
+                instantiated: Module {
+                    name: memories2,
+                    ..
+                },
+            }.rw,
+        ],
+        uninitialized_ios: {},
         io_targets: {
             Instance {
                 name: <simulator>::memories2,
@@ -606,506 +616,61 @@ Simulation {
                     name: memories2,
                     ..
                 },
-        }.rw: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bundle {
-                    /* offset = 0 */
-                    addr: UInt<3>,
-                    /* offset = 3 */
-                    en: Bool,
-                    /* offset = 4 */
-                    clk: Clock,
-                    #[hdl(flip)] /* offset = 5 */
-                    rdata: UInt<2>,
-                    /* offset = 7 */
-                    wmode: Bool,
-                    /* offset = 8 */
-                    wdata: UInt<2>,
-                    /* offset = 10 */
-                    wmask: Bool,
-                },
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 7,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(memories2: memories2).memories2::rw.addr",
-                                ty: UInt<3>,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(memories2: memories2).memories2::rw.en",
-                                ty: Bool,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(memories2: memories2).memories2::rw.clk",
-                                ty: Clock,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(memories2: memories2).memories2::rw.rdata",
-                                ty: UInt<2>,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(memories2: memories2).memories2::rw.wmode",
-                                ty: Bool,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(memories2: memories2).memories2::rw.wdata",
-                                ty: UInt<2>,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(memories2: memories2).memories2::rw.wmask",
-                                ty: Bool,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Bundle {
-                    fields: [
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(0),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: UInt<3>,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: UInt<3>,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(1),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: Bool,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: Bool,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(2),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: Clock,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: Clock,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(3),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: UInt<2>,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: UInt<2>,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(4),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: Bool,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: Bool,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(5),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: UInt<2>,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: UInt<2>,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(6),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: Bool,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: Bool,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                    ],
-                },
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 7 },
-            },
-            write: None,
-        },
+            }.rw,
             Instance {
                 name: <simulator>::memories2,
                 instantiated: Module {
                     name: memories2,
                     ..
                 },
-        }.rw.addr: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: UInt<3>,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: UInt<3>,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 1 },
-            },
-            write: None,
-        },
+            }.rw.addr,
             Instance {
                 name: <simulator>::memories2,
                 instantiated: Module {
                     name: memories2,
                     ..
                 },
-        }.rw.clk: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Clock,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: Clock,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 2, len: 1 },
-            },
-            write: None,
-        },
+            }.rw.clk,
             Instance {
                 name: <simulator>::memories2,
                 instantiated: Module {
                     name: memories2,
                     ..
                 },
-        }.rw.en: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bool,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: Bool,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 1, len: 1 },
-            },
-            write: None,
-        },
+            }.rw.en,
             Instance {
                 name: <simulator>::memories2,
                 instantiated: Module {
                     name: memories2,
                     ..
                 },
-        }.rw.rdata: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: UInt<2>,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: UInt<2>,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 3, len: 1 },
-            },
-            write: None,
-        },
+            }.rw.rdata,
             Instance {
                 name: <simulator>::memories2,
                 instantiated: Module {
                     name: memories2,
                     ..
                 },
-        }.rw.wdata: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: UInt<2>,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: UInt<2>,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 5, len: 1 },
-            },
-            write: None,
-        },
+            }.rw.wdata,
             Instance {
                 name: <simulator>::memories2,
                 instantiated: Module {
                     name: memories2,
                     ..
                 },
-        }.rw.wmask: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bool,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: Bool,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 6, len: 1 },
-            },
-            write: None,
-        },
+            }.rw.wmask,
             Instance {
                 name: <simulator>::memories2,
                 instantiated: Module {
                     name: memories2,
                     ..
                 },
-        }.rw.wmode: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bool,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
+            }.rw.wmode,
         },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: Bool,
+        did_initial_settle: true,
     },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 4, len: 1 },
-            },
-            write: None,
-        },
-    },
-    made_initial_step: true,
-    needs_settle: false,
+    extern_modules: [],
+    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "memories2",
         children: [

crates/fayalite/tests/sim/expected/mod1.txt

@@ -216,7 +216,17 @@ Simulation {
             ..
         },
     },
-    uninitialized_inputs: {},
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::mod1,
+                instantiated: Module {
+                    name: mod1,
+                    ..
+                },
+            }.o,
+        ],
+        uninitialized_ios: {},
         io_targets: {
             Instance {
                 name: <simulator>::mod1,
@@ -224,305 +234,40 @@ Simulation {
                     name: mod1,
                     ..
                 },
-        }.o: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bundle {
-                    #[hdl(flip)] /* offset = 0 */
-                    i: UInt<4>,
-                    /* offset = 4 */
-                    o: SInt<2>,
-                    #[hdl(flip)] /* offset = 6 */
-                    i2: SInt<2>,
-                    /* offset = 8 */
-                    o2: UInt<4>,
-                },
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 4,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(mod1: mod1).mod1::o.i",
-                                ty: UInt<4>,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(mod1: mod1).mod1::o.o",
-                                ty: SInt<2>,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(mod1: mod1).mod1::o.i2",
-                                ty: SInt<2>,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(mod1: mod1).mod1::o.o2",
-                                ty: UInt<4>,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Bundle {
-                    fields: [
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(0),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: UInt<4>,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: UInt<4>,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(1),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: SInt<2>,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: SInt<2>,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(2),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: SInt<2>,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: SInt<2>,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(3),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: UInt<4>,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: UInt<4>,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                    ],
-                },
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 4 },
-            },
-            write: None,
-        },
+            }.o,
             Instance {
                 name: <simulator>::mod1,
                 instantiated: Module {
                     name: mod1,
                     ..
                 },
-        }.o.i: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: UInt<4>,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: UInt<4>,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 1 },
-            },
-            write: None,
-        },
+            }.o.i,
             Instance {
                 name: <simulator>::mod1,
                 instantiated: Module {
                     name: mod1,
                     ..
                 },
-        }.o.i2: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: SInt<2>,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: SInt<2>,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 2, len: 1 },
-            },
-            write: None,
-        },
+            }.o.i2,
             Instance {
                 name: <simulator>::mod1,
                 instantiated: Module {
                     name: mod1,
                     ..
                 },
-        }.o.o: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: SInt<2>,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: SInt<2>,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 1, len: 1 },
-            },
-            write: None,
-        },
+            }.o.o,
             Instance {
                 name: <simulator>::mod1,
                 instantiated: Module {
                     name: mod1,
                     ..
                 },
-        }.o.o2: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: UInt<4>,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
+            }.o.o2,
         },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: UInt<4>,
+        did_initial_settle: true,
     },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 3, len: 1 },
-            },
-            write: None,
-        },
-    },
-    made_initial_step: true,
-    needs_settle: false,
+    extern_modules: [],
+    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "mod1",
         children: [

crates/fayalite/tests/sim/expected/shift_register.txt

@@ -265,7 +265,31 @@ Simulation {
             ..
         },
     },
-    uninitialized_inputs: {},
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::shift_register,
+                instantiated: Module {
+                    name: shift_register,
+                    ..
+                },
+            }.cd,
+            Instance {
+                name: <simulator>::shift_register,
+                instantiated: Module {
+                    name: shift_register,
+                    ..
+                },
+            }.d,
+            Instance {
+                name: <simulator>::shift_register,
+                instantiated: Module {
+                    name: shift_register,
+                    ..
+                },
+            }.q,
+        ],
+        uninitialized_ios: {},
         io_targets: {
             Instance {
                 name: <simulator>::shift_register,
@@ -273,239 +297,40 @@ Simulation {
                     name: shift_register,
                     ..
                 },
-        }.cd: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bundle {
-                    /* offset = 0 */
-                    clk: Clock,
-                    /* offset = 1 */
-                    rst: SyncReset,
-                },
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 2,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(shift_register: shift_register).shift_register::cd.clk",
-                                ty: Clock,
-                            },
-                            SlotDebugData {
-                                name: "InstantiatedModule(shift_register: shift_register).shift_register::cd.rst",
-                                ty: SyncReset,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Bundle {
-                    fields: [
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(0),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: Clock,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: Clock,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                        CompiledBundleField {
-                            offset: TypeIndex {
-                                small_slots: StatePartIndex<SmallSlots>(0),
-                                big_slots: StatePartIndex<BigSlots>(1),
-                            },
-                            ty: CompiledTypeLayout {
-                                ty: SyncReset,
-                                layout: TypeLayout {
-                                    small_slots: StatePartLayout<SmallSlots> {
-                                        len: 0,
-                                        debug_data: [],
-                                        ..
-                                    },
-                                    big_slots: StatePartLayout<BigSlots> {
-                                        len: 1,
-                                        debug_data: [
-                                            SlotDebugData {
-                                                name: "",
-                                                ty: SyncReset,
-                                            },
-                                        ],
-                                        ..
-                                    },
-                                },
-                                body: Scalar,
-                            },
-                        },
-                    ],
-                },
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 2 },
-            },
-            write: None,
-        },
+            }.cd,
             Instance {
                 name: <simulator>::shift_register,
                 instantiated: Module {
                     name: shift_register,
                     ..
                 },
-        }.cd.clk: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Clock,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: Clock,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 1 },
-            },
-            write: None,
-        },
+            }.cd.clk,
             Instance {
                 name: <simulator>::shift_register,
                 instantiated: Module {
                     name: shift_register,
                     ..
                 },
-        }.cd.rst: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: SyncReset,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "",
-                                ty: SyncReset,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 1, len: 1 },
-            },
-            write: None,
-        },
+            }.cd.rst,
             Instance {
                 name: <simulator>::shift_register,
                 instantiated: Module {
                     name: shift_register,
                     ..
                 },
-        }.d: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bool,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
-                    },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(shift_register: shift_register).shift_register::d",
-                                ty: Bool,
-                            },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 2, len: 1 },
-            },
-            write: None,
-        },
+            }.d,
             Instance {
                 name: <simulator>::shift_register,
                 instantiated: Module {
                     name: shift_register,
                     ..
                 },
-        }.q: CompiledValue {
-            layout: CompiledTypeLayout {
-                ty: Bool,
-                layout: TypeLayout {
-                    small_slots: StatePartLayout<SmallSlots> {
-                        len: 0,
-                        debug_data: [],
-                        ..
+            }.q,
         },
-                    big_slots: StatePartLayout<BigSlots> {
-                        len: 1,
-                        debug_data: [
-                            SlotDebugData {
-                                name: "InstantiatedModule(shift_register: shift_register).shift_register::q",
-                                ty: Bool,
+        did_initial_settle: true,
     },
-                        ],
-                        ..
-                    },
-                },
-                body: Scalar,
-            },
-            range: TypeIndexRange {
-                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                big_slots: StatePartIndexRange<BigSlots> { start: 3, len: 1 },
-            },
-            write: None,
-        },
-    },
-    made_initial_step: true,
-    needs_settle: false,
+    extern_modules: [],
+    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "shift_register",
         children: [

crates/fayalite/tests/ui/simvalue_is_not_internable.rs

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+//! check that SimValue can't be interned, since equality may ignore types
+
+use fayalite::{
+    intern::{Intern, Interned},
+    sim::value::SimValue,
+};
+
+fn f(v: SimValue<()>) -> Interned<SimValue<()>> {
+    Intern::intern_sized(v)
+}
+
+fn main() {}

crates/fayalite/tests/ui/simvalue_is_not_internable.stderr

@@ -0,0 +1,178 @@
+error[E0277]: `Cell<util::alternating_cell::State>` cannot be shared between threads safely
+  --> tests/ui/simvalue_is_not_internable.rs:11:26
+   |
+11 | fn f(v: SimValue<()>) -> Interned<SimValue<()>> {
+   |                          ^^^^^^^^^^^^^^^^^^^^^^ `Cell<util::alternating_cell::State>` cannot be shared between threads safely
+   |
+   = help: within `SimValue<()>`, the trait `Sync` is not implemented for `Cell<util::alternating_cell::State>`, which is required by `SimValue<()>: Sync`
+   = note: if you want to do aliasing and mutation between multiple threads, use `std::sync::RwLock`
+note: required because it appears within the type `util::alternating_cell::AlternatingCell<value::SimValueInner<()>>`
+  --> src/util/alternating_cell.rs
+   |
+   | pub(crate) struct AlternatingCell<T: ?Sized> {
+   |                   ^^^^^^^^^^^^^^^
+note: required because it appears within the type `SimValue<()>`
+  --> src/sim/value.rs
+   |
+   | pub struct SimValue<T: Type> {
+   |            ^^^^^^^^
+note: required by a bound in `fayalite::intern::Interned`
+  --> src/intern.rs
+   |
+   | pub struct Interned<T: ?Sized + 'static + Send + Sync> {
+   |                                                  ^^^^ required by this bound in `Interned`
+
+error[E0277]: `UnsafeCell<value::SimValueInner<()>>` cannot be shared between threads safely
+  --> tests/ui/simvalue_is_not_internable.rs:11:26
+   |
+11 | fn f(v: SimValue<()>) -> Interned<SimValue<()>> {
+   |                          ^^^^^^^^^^^^^^^^^^^^^^ `UnsafeCell<value::SimValueInner<()>>` cannot be shared between threads safely
+   |
+   = help: within `SimValue<()>`, the trait `Sync` is not implemented for `UnsafeCell<value::SimValueInner<()>>`, which is required by `SimValue<()>: Sync`
+note: required because it appears within the type `util::alternating_cell::AlternatingCell<value::SimValueInner<()>>`
+  --> src/util/alternating_cell.rs
+   |
+   | pub(crate) struct AlternatingCell<T: ?Sized> {
+   |                   ^^^^^^^^^^^^^^^
+note: required because it appears within the type `SimValue<()>`
+  --> src/sim/value.rs
+   |
+   | pub struct SimValue<T: Type> {
+   |            ^^^^^^^^
+note: required by a bound in `fayalite::intern::Interned`
+  --> src/intern.rs
+   |
+   | pub struct Interned<T: ?Sized + 'static + Send + Sync> {
+   |                                                  ^^^^ required by this bound in `Interned`
+
+error[E0277]: the trait bound `SimValue<()>: Intern` is not satisfied
+  --> tests/ui/simvalue_is_not_internable.rs:12:26
+   |
+12 |     Intern::intern_sized(v)
+   |     -------------------- ^ the trait `Hash` is not implemented for `SimValue<()>`, which is required by `SimValue<()>: Intern`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: the following other types implement trait `Intern`:
+             BitSlice
+             [T]
+             str
+   = note: required for `SimValue<()>` to implement `Intern`
+
+error[E0277]: the trait bound `SimValue<()>: Intern` is not satisfied
+  --> tests/ui/simvalue_is_not_internable.rs:12:26
+   |
+12 |     Intern::intern_sized(v)
+   |     -------------------- ^ the trait `std::cmp::Eq` is not implemented for `SimValue<()>`, which is required by `SimValue<()>: Intern`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: the following other types implement trait `Intern`:
+             BitSlice
+             [T]
+             str
+   = note: required for `SimValue<()>` to implement `Intern`
+
+error[E0277]: `Cell<util::alternating_cell::State>` cannot be shared between threads safely
+  --> tests/ui/simvalue_is_not_internable.rs:12:26
+   |
+12 |     Intern::intern_sized(v)
+   |     -------------------- ^ `Cell<util::alternating_cell::State>` cannot be shared between threads safely
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: within `SimValue<()>`, the trait `Sync` is not implemented for `Cell<util::alternating_cell::State>`, which is required by `SimValue<()>: Sync`
+   = note: if you want to do aliasing and mutation between multiple threads, use `std::sync::RwLock`
+note: required because it appears within the type `util::alternating_cell::AlternatingCell<value::SimValueInner<()>>`
+  --> src/util/alternating_cell.rs
+   |
+   | pub(crate) struct AlternatingCell<T: ?Sized> {
+   |                   ^^^^^^^^^^^^^^^
+note: required because it appears within the type `SimValue<()>`
+  --> src/sim/value.rs
+   |
+   | pub struct SimValue<T: Type> {
+   |            ^^^^^^^^
+note: required by a bound in `intern_sized`
+  --> src/intern.rs
+   |
+   | pub trait Intern: Any + Send + Sync {
+   |                                ^^^^ required by this bound in `Intern::intern_sized`
+   |     fn intern(&self) -> Interned<Self>;
+   |     fn intern_sized(self) -> Interned<Self>
+   |        ------------ required by a bound in this associated function
+
+error[E0277]: `UnsafeCell<value::SimValueInner<()>>` cannot be shared between threads safely
+  --> tests/ui/simvalue_is_not_internable.rs:12:26
+   |
+12 |     Intern::intern_sized(v)
+   |     -------------------- ^ `UnsafeCell<value::SimValueInner<()>>` cannot be shared between threads safely
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: within `SimValue<()>`, the trait `Sync` is not implemented for `UnsafeCell<value::SimValueInner<()>>`, which is required by `SimValue<()>: Sync`
+note: required because it appears within the type `util::alternating_cell::AlternatingCell<value::SimValueInner<()>>`
+  --> src/util/alternating_cell.rs
+   |
+   | pub(crate) struct AlternatingCell<T: ?Sized> {
+   |                   ^^^^^^^^^^^^^^^
+note: required because it appears within the type `SimValue<()>`
+  --> src/sim/value.rs
+   |
+   | pub struct SimValue<T: Type> {
+   |            ^^^^^^^^
+note: required by a bound in `intern_sized`
+  --> src/intern.rs
+   |
+   | pub trait Intern: Any + Send + Sync {
+   |                                ^^^^ required by this bound in `Intern::intern_sized`
+   |     fn intern(&self) -> Interned<Self>;
+   |     fn intern_sized(self) -> Interned<Self>
+   |        ------------ required by a bound in this associated function
+
+error[E0277]: `Cell<util::alternating_cell::State>` cannot be shared between threads safely
+  --> tests/ui/simvalue_is_not_internable.rs:12:5
+   |
+12 |     Intern::intern_sized(v)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^ `Cell<util::alternating_cell::State>` cannot be shared between threads safely
+   |
+   = help: within `SimValue<()>`, the trait `Sync` is not implemented for `Cell<util::alternating_cell::State>`, which is required by `SimValue<()>: Sync`
+   = note: if you want to do aliasing and mutation between multiple threads, use `std::sync::RwLock`
+note: required because it appears within the type `util::alternating_cell::AlternatingCell<value::SimValueInner<()>>`
+  --> src/util/alternating_cell.rs
+   |
+   | pub(crate) struct AlternatingCell<T: ?Sized> {
+   |                   ^^^^^^^^^^^^^^^
+note: required because it appears within the type `SimValue<()>`
+  --> src/sim/value.rs
+   |
+   | pub struct SimValue<T: Type> {
+   |            ^^^^^^^^
+note: required by a bound in `fayalite::intern::Interned`
+  --> src/intern.rs
+   |
+   | pub struct Interned<T: ?Sized + 'static + Send + Sync> {
+   |                                                  ^^^^ required by this bound in `Interned`
+
+error[E0277]: `UnsafeCell<value::SimValueInner<()>>` cannot be shared between threads safely
+  --> tests/ui/simvalue_is_not_internable.rs:12:5
+   |
+12 |     Intern::intern_sized(v)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^ `UnsafeCell<value::SimValueInner<()>>` cannot be shared between threads safely
+   |
+   = help: within `SimValue<()>`, the trait `Sync` is not implemented for `UnsafeCell<value::SimValueInner<()>>`, which is required by `SimValue<()>: Sync`
+note: required because it appears within the type `util::alternating_cell::AlternatingCell<value::SimValueInner<()>>`
+  --> src/util/alternating_cell.rs
+   |
+   | pub(crate) struct AlternatingCell<T: ?Sized> {
+   |                   ^^^^^^^^^^^^^^^
+note: required because it appears within the type `SimValue<()>`
+  --> src/sim/value.rs
+   |
+   | pub struct SimValue<T: Type> {
+   |            ^^^^^^^^
+note: required by a bound in `fayalite::intern::Interned`
+  --> src/intern.rs
+   |
+   | pub struct Interned<T: ?Sized + 'static + Send + Sync> {
+   |                                                  ^^^^ required by this bound in `Interned`

crates/fayalite/visit_types.json

@@ -49,7 +49,8 @@
                 "AsyncReset": "Visible",
                 "SyncReset": "Visible",
                 "Reset": "Visible",
-                "Clock": "Visible"
+                "Clock": "Visible",
+                "PhantomConst": "Visible"
             }
         },
         "Bundle": {
@@ -159,7 +160,8 @@
             "data": {
                 "$kind": "Struct",
                 "verilog_name": "Visible",
-                "parameters": "Visible"
+                "parameters": "Visible",
+                "simulation": "Visible"
             }
         },
         "ExternModuleParameter": {
@@ -1262,6 +1264,17 @@
                 "ArrayElement": "Visible",
                 "DynArrayElement": "Visible"
             }
+        },
+        "PhantomConst": {
+            "data": {
+                "$kind": "Opaque"
+            },
+            "generics": "<T: ?Sized + crate::phantom_const::PhantomConstValue>"
+        },
+        "ExternModuleSimulation": {
+            "data": {
+                "$kind": "Opaque"
+            }
         }
     }
 }