WIP working on implementing deduce_resets pass

crates/fayalite/src/module.rs

@@ -180,7 +180,7 @@ impl Block {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
 pub struct StmtConnect {
     pub lhs: Expr<CanonicalType>,
     pub rhs: Expr<CanonicalType>,
@@ -235,7 +235,7 @@ impl fmt::Debug for StmtConnect {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
 pub struct StmtFormal {
     pub kind: FormalKind,
     pub clk: Expr<Clock>,
@@ -284,6 +284,8 @@ pub struct StmtIf<S: ModuleBuildingStatus = ModuleBuilt> {
     pub blocks: [S::Block; 2],
 }
 
+impl Copy for StmtIf {}
+
 impl<S: ModuleBuildingStatus> StmtIf<S> {
     pub fn then_block(&self) -> S::Block {
         self.blocks[0]
@@ -315,6 +317,8 @@ pub struct StmtMatch<S: ModuleBuildingStatus = ModuleBuilt> {
     pub blocks: Interned<[S::Block]>,
 }
 
+impl Copy for StmtMatch {}
+
 impl StmtMatch {
     #[track_caller]
     fn assert_validity(&self) {
@@ -459,6 +463,8 @@ pub struct StmtWire<S: ModuleBuildingStatus = ModuleBuilt> {
     pub wire: Wire<CanonicalType>,
 }
 
+impl Copy for StmtWire {}
+
 #[derive(Hash, Clone, PartialEq, Eq, Debug)]
 pub struct StmtReg<S: ModuleBuildingStatus = ModuleBuilt> {
     pub annotations: S::StmtAnnotations,
@@ -473,6 +479,8 @@ pub struct StmtInstance<S: ModuleBuildingStatus = ModuleBuilt> {
     pub instance: Instance<Bundle>,
 }
 
+impl Copy for StmtInstance {}
+
 wrapper_enum! {
     #[impl(
         (<S: ModuleBuildingStatus>) self: StmtDeclaration<S> = self,
@@ -490,6 +498,8 @@ wrapper_enum! {
     }
 }
 
+impl Copy for StmtDeclaration {}
+
 impl<S: ModuleBuildingStatus> StmtDeclaration<S> {
     pub fn annotations(&self) -> S::StmtAnnotations {
         match self {
@@ -546,6 +556,8 @@ wrapper_enum! {
     }
 }
 
+impl Copy for Stmt {}
+
 impl<S: ModuleBuildingStatus> Stmt<S> {
     pub fn sub_stmt_blocks(&self) -> &[S::Block] {
         match self {

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

@@ -2,20 +2,28 @@
 // See Notices.txt for copyright information
 
 use hashbrown::{hash_map::Entry, HashMap};
-use petgraph::graph::{NodeIndex, UnGraph};
+use petgraph::{
+    graph::{NodeIndex, UnGraph},
+    unionfind::UnionFind,
+};
 
 use crate::{
     bundle::{BundleField, BundleType},
     enum_::{EnumType, EnumVariant},
-    expr::target::{TargetPathArrayElement, TargetPathBundleField, TargetPathElement},
+    expr::{
+        ops,
+        target::{TargetBase, TargetPathArrayElement, TargetPathBundleField, TargetPathElement},
+        Flow,
+    },
     intern::{Intern, Interned, Memoize},
     module::{
-        AnnotatedModuleIO, ExprInInstantiatedModule, ExternModuleBody, InstantiatedModule,
-        ModuleBody, NormalModuleBody, TargetInInstantiatedModule,
+        AnnotatedModuleIO, Block, ExprInInstantiatedModule, ExternModuleBody, InstantiatedModule,
+        ModuleBody, ModuleIO, NormalModuleBody, Stmt, StmtConnect, StmtDeclaration, StmtFormal,
+        StmtIf, StmtInstance, StmtMatch, StmtReg, StmtWire, TargetInInstantiatedModule,
     },
     prelude::*,
 };
-use std::fmt;
+use std::{convert::Infallible, fmt};
 
 #[derive(Debug)]
 pub enum DeduceResetsError {
@@ -40,18 +48,132 @@ impl From<DeduceResetsError> for std::io::Error {
     }
 }
 
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+enum ResetTarget {
+    Base {
+        base: Interned<TargetBase>,
+    },
+    BundleField {
+        parent: Interned<ResetTarget>,
+        field_ty: CanonicalType,
+        field_index: usize,
+    },
+    EnumVariant {
+        parent: Interned<ResetTarget>,
+        variant_ty: CanonicalType,
+        variant_index: usize,
+    },
+    /// Array's Elements:
+    /// deduce_resets requires all array elements to deduce to the same pattern of async/sync resets,
+    /// so we don't track individual array elements but instead track all of an array's elements together.
+    ArraysElements {
+        parent: Interned<ResetTarget>,
+        element_ty: CanonicalType,
+    },
+}
+
+impl ResetTarget {
+    fn canonical_ty(self) -> CanonicalType {
+        match self {
+            ResetTarget::Base { base } => base.canonical_ty(),
+            ResetTarget::BundleField { field_ty, .. } => field_ty,
+            ResetTarget::EnumVariant { variant_ty, .. } => variant_ty,
+            ResetTarget::ArraysElements { element_ty, .. } => element_ty,
+        }
+    }
+    fn parent(self) -> Option<Interned<ResetTarget>> {
+        match self {
+            ResetTarget::Base { .. } => None,
+            ResetTarget::BundleField { parent, .. }
+            | ResetTarget::EnumVariant { parent, .. }
+            | ResetTarget::ArraysElements { parent, .. } => Some(parent),
+        }
+    }
+    fn base(mut self) -> Interned<TargetBase> {
+        loop {
+            match self {
+                ResetTarget::Base { base } => break base,
+                ResetTarget::BundleField { parent, .. }
+                | ResetTarget::EnumVariant { parent, .. }
+                | ResetTarget::ArraysElements { parent, .. } => self = *parent,
+            }
+        }
+    }
+    fn bundle_field(self, field_index: usize) -> Self {
+        let field_ty = Bundle::from_canonical(self.canonical_ty()).fields()[field_index].ty;
+        Self::BundleField {
+            parent: self.intern_sized(),
+            field_ty,
+            field_index,
+        }
+    }
+    fn enum_variant(self, variant_index: usize) -> Self {
+        let variant_ty = Enum::from_canonical(self.canonical_ty()).variants()[variant_index]
+            .ty
+            .expect("known to have a variant field");
+        Self::EnumVariant {
+            parent: self.intern_sized(),
+            variant_ty,
+            variant_index,
+        }
+    }
+    fn arrays_elements(self) -> Self {
+        let element_ty = <Array>::from_canonical(self.canonical_ty()).element();
+        Self::ArraysElements {
+            parent: self.intern_sized(),
+            element_ty,
+        }
+    }
+    fn for_each_child<E>(self, mut f: impl FnMut(ResetTarget) -> Result<(), E>) -> Result<(), E> {
+        match self.canonical_ty() {
+            CanonicalType::UInt(_)
+            | CanonicalType::SInt(_)
+            | CanonicalType::Bool(_)
+            | CanonicalType::AsyncReset(_)
+            | CanonicalType::SyncReset(_)
+            | CanonicalType::Reset(_)
+            | CanonicalType::Clock(_) => Ok(()),
+            CanonicalType::Array(_) => f(self.arrays_elements()),
+            CanonicalType::Enum(ty) => {
+                for variant_index in 0..ty.variants().len() {
+                    f(self.enum_variant(variant_index))?;
+                }
+                Ok(())
+            }
+            CanonicalType::Bundle(ty) => {
+                for field_index in 0..ty.fields().len() {
+                    f(self.bundle_field(field_index))?;
+                }
+                Ok(())
+            }
+        }
+    }
+}
+
+impl<T: Into<TargetBase>> From<T> for ResetTarget {
+    fn from(base: T) -> Self {
+        ResetTarget::Base {
+            base: TargetBase::intern_sized(base.into()),
+        }
+    }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+struct ResetTargetInInstantiatedModule {
+    instantiated_module: InstantiatedModule,
+    target: ResetTarget,
+}
+
 #[derive(Debug)]
 struct Node {
-    target: TargetInInstantiatedModule,
+    target: ResetTargetInInstantiatedModule,
     deduced_type: Option<CanonicalType>,
 }
 
 #[derive(Debug)]
 struct State {
     base_module: Interned<Module<Bundle>>,
-    transformed_exprs:
-        HashMap<ExprInInstantiatedModule<CanonicalType>, ExprInInstantiatedModule<CanonicalType>>,
-    node_ids: HashMap<TargetInInstantiatedModule, NodeIndex<u32>>,
+    node_ids: HashMap<ResetTargetInInstantiatedModule, NodeIndex<u32>>,
     graph: UnGraph<Node, ()>,
     fallback_to_sync_reset: bool,
 }
@@ -89,88 +211,499 @@ fn type_contains_any_undeduced_resets(ty: CanonicalType) -> bool {
     MyMemoize.get_owned(ty)
 }
 
-impl State {
-    fn add_target_to_graph_recursive(
-        &mut self,
-        target: TargetInInstantiatedModule,
-    ) -> NodeIndex<u32> {
-        let entry = match self.node_ids.entry(target) {
-            Entry::Vacant(entry) => entry,
-            Entry::Occupied(entry) => {
-                return *entry.get();
-            }
+trait ProcessStep {
+    type Error;
+    type Processed<T>;
+    fn processed_as_ref<T>(v: &Self::Processed<T>) -> Self::Processed<&T>;
+    fn processed_as_mut<T>(v: &mut Self::Processed<T>) -> Self::Processed<&mut T>;
+    fn processed_zip<T, U>(t: Self::Processed<T>, u: Self::Processed<U>)
+        -> Self::Processed<(T, U)>;
+    fn processed_map<T, U>(v: Self::Processed<T>, f: impl FnOnce(T) -> U) -> Self::Processed<U>;
+    fn processed_make<T>(t: T) -> Self::Processed<T>;
+    fn processed_from_iter<T, O: FromIterator<T>>(
+        iter: impl IntoIterator<Item = Self::Processed<T>>,
+    ) -> Self::Processed<O>;
+}
+
+macro_rules! impl_process_step_with_empty_processed {
+    () => {
+        type Processed<T> = ();
+        fn processed_as_ref<T>(v: &Self::Processed<T>) -> Self::Processed<&T> {
+            *v
+        }
+        fn processed_as_mut<T>(v: &mut Self::Processed<T>) -> Self::Processed<&mut T> {
+            *v
+        }
+        fn processed_zip<T, U>(
+            t: Self::Processed<T>,
+            u: Self::Processed<U>,
+        ) -> Self::Processed<(T, U)> {
+            let _ = t;
+            let _ = u;
+            ()
+        }
+        fn processed_map<T, U>(
+            v: Self::Processed<T>,
+            f: impl FnOnce(T) -> U,
+        ) -> Self::Processed<U> {
+            let _ = f;
+            v
+        }
+        fn processed_make<T>(t: T) -> Self::Processed<T> {
+            let _ = t;
+            ()
+        }
+        fn processed_from_iter<T, O: FromIterator<T>>(
+            iter: impl IntoIterator<Item = Self::Processed<T>>,
+        ) -> Self::Processed<O> {
+            FromIterator::from_iter(iter)
+        }
+    };
+}
+
+struct Processed<T, Step: ProcessStep>(Step::Processed<T>);
+
+impl<T, Step: ProcessStep> Processed<T, Step> {
+    fn as_ref(&self) -> Processed<&T, Step> {
+        Processed(Step::processed_as_ref(&self.0))
+    }
+    fn as_mut(&mut self) -> Processed<&mut T, Step> {
+        Processed(Step::processed_as_mut(&mut self.0))
+    }
+    fn zip<U>(self, u: Processed<U, Step>) -> Processed<(T, U), Step> {
+        Processed(Step::processed_zip(self.0, u.0))
+    }
+    fn new(v: T) -> Self {
+        Processed(Step::processed_make(v))
+    }
+    fn map<U>(self, f: impl FnOnce(T) -> U) -> Processed<U, Step> {
+        Processed(Step::processed_map(self.0, f))
+    }
+}
+
+impl<C: FromIterator<A>, A, Step: ProcessStep> FromIterator<Processed<A, Step>>
+    for Processed<C, Step>
+{
+    fn from_iter<T: IntoIterator<Item = Processed<A, Step>>>(iter: T) -> Self {
+        Processed(Step::processed_from_iter(iter.into_iter().map(|v| v.0)))
+    }
+}
+
+struct AddNodesToGraphStep;
+
+impl ProcessStep for AddNodesToGraphStep {
+    type Error = Infallible;
+    impl_process_step_with_empty_processed!();
+}
+
+struct AddEdgesToGraphStep {
+    union_find: UnionFind<u32>,
+}
+
+impl ProcessStep for AddEdgesToGraphStep {
+    type Error = Infallible;
+    impl_process_step_with_empty_processed!();
+}
+
+trait RunProcessStep<Step: ProcessStep>: Sized {
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error>;
+}
+
+impl RunProcessStep<AddNodesToGraphStep> for ResetTarget {
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut AddNodesToGraphStep,
+    ) -> Result<Processed<Self, AddNodesToGraphStep>, Infallible> {
+        let target = ResetTargetInInstantiatedModule {
+            instantiated_module,
+            target: self,
         };
-        let ty = target.target.canonical_ty();
-        let node_id = self.graph.add_node(Node {
+        let Entry::Vacant(entry) = state.node_ids.entry(target) else {
+            return Ok(Processed(()));
+        };
+        let ty = self.canonical_ty();
+        let node_id = state.graph.add_node(Node {
             target,
             deduced_type: type_contains_any_undeduced_resets(ty).then_some(ty),
         });
         entry.insert(node_id);
-        match target.target.canonical_ty() {
-            CanonicalType::UInt(_)
-            | CanonicalType::SInt(_)
-            | CanonicalType::Bool(_)
-            | CanonicalType::AsyncReset(_)
-            | CanonicalType::SyncReset(_)
-            | CanonicalType::Clock(_) => {}
-            CanonicalType::Array(ty) => {
-                for index in 0..ty.len() {
-                    self.add_target_to_graph_recursive(TargetInInstantiatedModule {
-                        instantiated_module: target.instantiated_module,
-                        target: target.target.join(
-                            TargetPathElement::from(TargetPathArrayElement { index })
-                                .intern_sized(),
-                        ),
-                    });
-                }
-            }
-            CanonicalType::Enum(_) => {}
-            CanonicalType::Bundle(ty) => {
-                for BundleField { name, .. } in ty.fields() {
-                    self.add_target_to_graph_recursive(TargetInInstantiatedModule {
-                        instantiated_module: target.instantiated_module,
-                        target: target.target.join(
-                            TargetPathElement::from(TargetPathBundleField { name }).intern_sized(),
-                        ),
-                    });
-                }
-            }
-            CanonicalType::Reset(_) => {}
-        }
-        node_id
+        self.for_each_child(|target| -> Result<(), Infallible> {
+            target.run_process_step(instantiated_module, state, step)?;
+            Ok(())
+        })?;
+        Ok(Processed(()))
     }
-    fn build_graph_for_module(&mut self, instantiated_module: Interned<InstantiatedModule>) {
-        let Module {
-            name: _,
-            source_location: _,
-            body,
-            io_ty: _,
-            module_io,
-            module_annotations: _,
-        } = *instantiated_module.leaf_module();
-        for AnnotatedModuleIO {
-            annotations: _,
-            module_io,
-        } in module_io
-        {
-            self.add_target_to_graph_recursive(TargetInInstantiatedModule {
-                instantiated_module: *instantiated_module,
-                target: module_io.into(),
-            });
+}
+
+struct ConnectAndLhsInstantiatedModule {
+    lhs_instantiated_module: InstantiatedModule,
+    lhs: Expr<CanonicalType>,
+    rhs: Expr<CanonicalType>,
+    source_location: SourceLocation,
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for ConnectAndLhsInstantiatedModule {
+    fn run_process_step(
+        self,
+        rhs_instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        let Self {
+            lhs_instantiated_module,
+            lhs,
+            rhs,
+            source_location,
+        } = self;
+        todo!();
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for StmtConnect {
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        let StmtConnect {
+            lhs,
+            rhs,
+            source_location,
+        } = self;
+        Ok(ConnectAndLhsInstantiatedModule {
+            lhs_instantiated_module: instantiated_module,
+            lhs,
+            rhs,
+            source_location,
         }
-        match body {
-            ModuleBody::Normal(NormalModuleBody { body }) => todo!(),
-            ModuleBody::Extern(ExternModuleBody {
+        .run_process_step(instantiated_module, state, step)?
+        .map(
+            |ConnectAndLhsInstantiatedModule {
+                 lhs_instantiated_module: _,
+                 lhs,
+                 rhs,
+                 source_location,
+             }| StmtConnect {
+                lhs,
+                rhs,
+                source_location,
+            },
+        ))
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for StmtFormal {
+    fn run_process_step(
+        self,
+        _instantiated_module: InstantiatedModule,
+        _state: &mut State,
+        _step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        // no inputs are Reset
+        Ok(Processed::new(self))
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for StmtIf {
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        todo!()
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for StmtMatch {
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        todo!()
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for ModuleIO<CanonicalType>
+where
+    ResetTarget: RunProcessStep<Step>,
+{
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        Ok(ResetTarget::from(self)
+            .run_process_step(instantiated_module, state, step)?
+            .map(|target| {
+                let ResetTarget::Base { base } = target else {
+                    unreachable!();
+                };
+                let TargetBase::ModuleIO(module_io) = *base else {
+                    unreachable!();
+                };
+                module_io
+            }))
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for StmtWire
+where
+    ResetTarget: RunProcessStep<Step>,
+{
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        let Self { annotations, wire } = self;
+        Ok(ResetTarget::from(wire)
+            .run_process_step(instantiated_module, state, step)?
+            .map(|target| {
+                let ResetTarget::Base { base } = target else {
+                    unreachable!();
+                };
+                let TargetBase::Wire(wire) = *base else {
+                    unreachable!();
+                };
+                Self { annotations, wire }
+            }))
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for StmtReg
+where
+    ResetTarget: RunProcessStep<Step>,
+{
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        let Self { annotations, reg } = self;
+        Ok(ResetTarget::from(reg)
+            .run_process_step(instantiated_module, state, step)?
+            .map(|target| {
+                let ResetTarget::Base { base } = target else {
+                    unreachable!();
+                };
+                let TargetBase::Reg(reg) = *base else {
+                    unreachable!();
+                };
+                Self { annotations, reg }
+            }))
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for StmtInstance
+where
+    ResetTarget: RunProcessStep<Step>,
+{
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        let Self {
+            annotations,
+            instance,
+        } = self;
+        let child_instantiated_module = InstantiatedModule::Child {
+            parent: instantiated_module.intern_sized(),
+            instance: instance.intern_sized(),
+        };
+        instance
+            .instantiated()
+            .run_process_step(child_instantiated_module, state, step)?;
+        for (field_index, AnnotatedModuleIO { module_io, .. }) in
+            instance.instantiated().module_io().into_iter().enumerate()
+        {
+            let (lhs_instantiated_module, lhs, rhs_instantiated_module, rhs) = match module_io
+                .flow()
+            {
+                Flow::Source => {
+                    // connect to submodule's input from instance input
+                    (
+                        child_instantiated_module,
+                        module_io.to_expr(),
+                        instantiated_module,
+                        ops::FieldAccess::new_by_index(instance.to_expr(), field_index).to_expr(),
+                    )
+                }
+                Flow::Sink => {
+                    // connect to instance output from submodule's output
+                    (
+                        instantiated_module,
+                        ops::FieldAccess::new_by_index(instance.to_expr(), field_index).to_expr(),
+                        child_instantiated_module,
+                        module_io.to_expr(),
+                    )
+                }
+                Flow::Duplex => unreachable!(),
+            };
+            ConnectAndLhsInstantiatedModule {
+                lhs_instantiated_module,
+                lhs,
+                rhs,
+                source_location: instance.source_location(),
+            }
+            .run_process_step(rhs_instantiated_module, state, step)?;
+        }
+        Ok(ResetTarget::from(instance)
+            .run_process_step(instantiated_module, state, step)?
+            .map(|target| {
+                let ResetTarget::Base { base } = target else {
+                    unreachable!();
+                };
+                let TargetBase::Instance(instance) = *base else {
+                    unreachable!();
+                };
+                Self {
+                    annotations,
+                    instance,
+                }
+            }))
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for StmtDeclaration
+where
+    ResetTarget: RunProcessStep<Step>,
+{
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        Ok(match self {
+            StmtDeclaration::Wire(decl) => decl
+                .run_process_step(instantiated_module, state, step)?
+                .map(StmtDeclaration::from),
+            StmtDeclaration::Reg(decl) => decl
+                .run_process_step(instantiated_module, state, step)?
+                .map(StmtDeclaration::from),
+            StmtDeclaration::Instance(decl) => decl
+                .run_process_step(instantiated_module, state, step)?
+                .map(StmtDeclaration::from),
+        })
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for Stmt
+where
+    ResetTarget: RunProcessStep<Step>,
+{
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        Ok(match self {
+            Stmt::Connect(stmt) => stmt
+                .run_process_step(instantiated_module, state, step)?
+                .map(Stmt::from),
+            Stmt::Formal(stmt) => stmt
+                .run_process_step(instantiated_module, state, step)?
+                .map(Stmt::from),
+            Stmt::If(stmt) => stmt
+                .run_process_step(instantiated_module, state, step)?
+                .map(Stmt::from),
+            Stmt::Match(stmt) => stmt
+                .run_process_step(instantiated_module, state, step)?
+                .map(Stmt::from),
+            Stmt::Declaration(stmt) => stmt
+                .run_process_step(instantiated_module, state, step)?
+                .map(Stmt::from),
+        })
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for Block
+where
+    ResetTarget: RunProcessStep<Step>,
+{
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        let Block { memories, stmts } = self;
+        // memories and memory ports won't ever contain any Reset values,
+        // so always just use the old `memories` value. we add the ports to the graph anyway to make the other logic easier.
+        for memory in memories {
+            for port in memory.ports() {
+                ResetTarget::from(port).run_process_step(instantiated_module, state, step)?;
+            }
+        }
+        let stmts = Result::<Processed<_, _>, _>::from_iter(
+            stmts
+                .iter()
+                .map(|stmt| stmt.run_process_step(instantiated_module, state, step)),
+        )?;
+        Ok(stmts.map(|stmts| Block { memories, stmts }))
+    }
+}
+
+impl<Step: ProcessStep> RunProcessStep<Step> for Module<Bundle>
+where
+    ResetTarget: RunProcessStep<Step>,
+{
+    fn run_process_step(
+        self,
+        instantiated_module: InstantiatedModule,
+        state: &mut State,
+        step: &mut Step,
+    ) -> Result<Processed<Self, Step>, Step::Error> {
+        let module = *instantiated_module.leaf_module();
+        let module_io =
+            Result::<Processed<Interned<[_]>, _>, _>::from_iter(module.module_io().iter().map(
+                |&AnnotatedModuleIO {
+                     annotations,
+                     module_io,
+                 }| {
+                    Ok(module_io
+                        .run_process_step(instantiated_module, state, step)?
+                        .map(|module_io| AnnotatedModuleIO {
+                            annotations,
+                            module_io,
+                        }))
+                },
+            ))?;
+        let body = match module.body() {
+            ModuleBody::Normal(NormalModuleBody { body }) => body
+                .run_process_step(instantiated_module, state, step)?
+                .map(|body| ModuleBody::Normal(NormalModuleBody { body })),
+            body @ ModuleBody::Extern(ExternModuleBody {
                 verilog_name: _,
                 parameters: _,
-            }) => {}
-        }
-    }
-    fn deduce_types(&mut self) -> Result<(), DeduceResetsError> {
-        todo!()
-    }
-    fn transform_module(&mut self, module: Interned<Module<Bundle>>) -> Interned<Module<Bundle>> {
-        todo!()
+            }) => Processed::new(body),
+        };
+        Ok(module_io.zip(body).map(|(module_io, body)| {
+            Module::new_unchecked(
+                module.name_id(),
+                module.source_location(),
+                body,
+                module_io,
+                module.module_annotations(),
+            )
+        }))
     }
 }
 
@@ -180,12 +713,16 @@ pub fn deduce_resets(
 ) -> Result<Interned<Module<Bundle>>, DeduceResetsError> {
     let mut state = State {
         base_module: module,
-        transformed_exprs: HashMap::new(),
         node_ids: HashMap::new(),
         graph: UnGraph::new_undirected(),
         fallback_to_sync_reset,
     };
-    state.build_graph_for_module(InstantiatedModule::Base(module).intern_sized());
-    state.deduce_types()?;
-    Ok(state.transform_module(module))
+    let Ok(Processed(())) = module.run_process_step(
+        InstantiatedModule::Base(module),
+        &mut state,
+        &mut AddNodesToGraphStep,
+    );
+    todo!("add edges");
+    todo!("deduce types");
+    Ok(todo!("transform module"))
 }