diff --git a/crates/fayalite/src/build.rs b/crates/fayalite/src/build.rs
new file mode 100644
index 00000000..7b7165d5
--- /dev/null
+++ b/crates/fayalite/src/build.rs
@@ -0,0 +1,817 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+use crate::{
+    bundle::Bundle,
+    intern::Interned,
+    module::Module,
+    util::{HashMap, HashSet, job_server::AcquiredJob},
+};
+use hashbrown::hash_map::Entry;
+use petgraph::{
+    algo::{DfsSpace, kosaraju_scc, toposort},
+    graph::DiGraph,
+    visit::{GraphBase, Visitable},
+};
+use serde::{Deserialize, Deserializer, Serialize, Serializer, de::Error, ser::SerializeSeq};
+use std::{
+    any::{Any, TypeId},
+    collections::BTreeSet,
+    fmt::{self, Write},
+    hash::{Hash, Hasher},
+    iter, mem,
+    sync::Arc,
+};
+
+#[derive(Clone, Hash, PartialEq, Eq, Debug)]
+pub enum JobItem {
+    Module { value: Module<Bundle> },
+    File { path: Interned<str> },
+}
+
+impl JobItem {
+    pub fn name(&self) -> JobItemName {
+        match self {
+            JobItem::Module { value } => JobItemName::Module { name: value.name() },
+            &JobItem::File { path } => JobItemName::File { path },
+        }
+    }
+}
+
+#[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
+pub enum JobItemName {
+    Module { name: Interned<str> },
+    File { path: Interned<str> },
+}
+
+pub struct CommandLine {}
+
+pub trait JobKind: 'static + Send + Sync + Hash + Eq + fmt::Debug {
+    type Job: 'static + Send + Sync + Hash + Eq + fmt::Debug;
+    fn inputs(&self, job: &Self::Job) -> Interned<[JobItemName]>;
+    fn outputs(&self, job: &Self::Job) -> Interned<[JobItemName]>;
+    fn to_command_line(&self, job: &Self::Job) -> Interned<[Interned<str>]>;
+    fn parse_command_line(
+        &self,
+        command_line: Interned<[Interned<str>]>,
+    ) -> clap::error::Result<Self::Job>;
+    fn run(
+        &self,
+        job: &Self::Job,
+        inputs: &[JobItem],
+        acquired_job: &mut AcquiredJob,
+    ) -> eyre::Result<Vec<JobItem>>;
+}
+
+trait DynJobKindTrait: 'static + Send + Sync + fmt::Debug {
+    fn as_any(&self) -> &dyn Any;
+    fn as_arc_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync>;
+    fn eq_dyn(&self, other: &dyn DynJobKindTrait) -> bool;
+    fn hash_dyn(&self, state: &mut dyn Hasher);
+    fn parse_command_line_dyn(
+        self: Arc<Self>,
+        command_line: Interned<[Interned<str>]>,
+    ) -> clap::error::Result<DynJob>;
+}
+
+impl<T: JobKind> DynJobKindTrait for T {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn as_arc_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync> {
+        self
+    }
+
+    fn eq_dyn(&self, other: &dyn DynJobKindTrait) -> bool {
+        other
+            .as_any()
+            .downcast_ref::<T>()
+            .is_some_and(|other| self == other)
+    }
+
+    fn hash_dyn(&self, mut state: &mut dyn Hasher) {
+        self.hash(&mut state)
+    }
+
+    fn parse_command_line_dyn(
+        self: std::sync::Arc<T>,
+        command_line: Interned<[Interned<str>]>,
+    ) -> clap::error::Result<DynJob> {
+        let job = self.parse_command_line(command_line)?;
+        let inputs = self.inputs(&job);
+        let outputs = self.outputs(&job);
+        Ok(DynJob(Arc::new(inner::DynJob {
+            kind: self,
+            job,
+            inputs,
+            outputs,
+        })))
+    }
+}
+
+#[derive(Clone)]
+pub struct DynJobKind(Arc<dyn DynJobKindTrait>);
+
+impl DynJobKind {
+    pub fn from_arc<T: JobKind>(job_kind: Arc<T>) -> Self {
+        if TypeId::of::<T>() == TypeId::of::<Self>() {
+            Self::clone(
+                &Arc::downcast::<Self>(job_kind.as_arc_any())
+                    .ok()
+                    .expect("already checked type"),
+            )
+        } else {
+            Self(job_kind)
+        }
+    }
+    pub fn new<T: JobKind>(job_kind: T) -> Self {
+        if let Some(job_kind) = DynJobKindTrait::as_any(&job_kind).downcast_ref::<Self>() {
+            job_kind.clone()
+        } else {
+            Self(Arc::new(job_kind))
+        }
+    }
+    pub fn type_id(&self) -> TypeId {
+        DynJobKindTrait::as_any(&*self.0).type_id()
+    }
+    pub fn downcast_ref<T: JobKind>(&self) -> Option<&T> {
+        DynJobKindTrait::as_any(&*self.0).downcast_ref()
+    }
+    pub fn downcast_arc<T: JobKind>(self) -> Result<Arc<T>, Self> {
+        if self.downcast_ref::<T>().is_some() {
+            Ok(Arc::downcast::<T>(self.0.as_arc_any())
+                .ok()
+                .expect("already checked type"))
+        } else {
+            Err(self)
+        }
+    }
+    pub fn parse_command_line(
+        &self,
+        command_line: Interned<[Interned<str>]>,
+    ) -> clap::error::Result<DynJob> {
+        self.0.clone().parse_command_line_dyn(command_line)
+    }
+}
+
+impl Hash for DynJobKind {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        DynJobKindTrait::as_any(&*self.0).type_id().hash(state);
+        DynJobKindTrait::hash_dyn(&*self.0, state);
+    }
+}
+
+impl PartialEq for DynJobKind {
+    fn eq(&self, other: &Self) -> bool {
+        DynJobKindTrait::eq_dyn(&*self.0, &*other.0)
+    }
+}
+
+impl Eq for DynJobKind {}
+
+impl fmt::Debug for DynJobKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+trait DynJobTrait: 'static + Send + Sync + fmt::Debug {
+    fn as_any(&self) -> &dyn Any;
+    fn eq_dyn(&self, other: &dyn DynJobTrait) -> bool;
+    fn hash_dyn(&self, state: &mut dyn Hasher);
+    fn kind_type_id(&self) -> TypeId;
+    fn kind(&self) -> DynJobKind;
+    fn inputs(&self) -> Interned<[JobItemName]>;
+    fn outputs(&self) -> Interned<[JobItemName]>;
+    fn to_command_line(&self) -> Interned<[Interned<str>]>;
+    fn run(&self, inputs: &[JobItem], acquired_job: &mut AcquiredJob)
+    -> eyre::Result<Vec<JobItem>>;
+}
+
+mod inner {
+    use super::*;
+
+    #[derive(Debug, PartialEq, Eq, Hash)]
+    pub(crate) struct DynJob<T: JobKind> {
+        pub(crate) kind: Arc<T>,
+        pub(crate) job: T::Job,
+        pub(crate) inputs: Interned<[JobItemName]>,
+        pub(crate) outputs: Interned<[JobItemName]>,
+    }
+}
+
+impl<T: JobKind> DynJobTrait for inner::DynJob<T> {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn eq_dyn(&self, other: &dyn DynJobTrait) -> bool {
+        other
+            .as_any()
+            .downcast_ref::<inner::DynJob<T>>()
+            .is_some_and(|other| self == other)
+    }
+
+    fn hash_dyn(&self, mut state: &mut dyn Hasher) {
+        self.hash(&mut state);
+    }
+
+    fn kind_type_id(&self) -> TypeId {
+        TypeId::of::<T>()
+    }
+
+    fn kind(&self) -> DynJobKind {
+        DynJobKind(self.kind.clone())
+    }
+
+    fn inputs(&self) -> Interned<[JobItemName]> {
+        self.inputs
+    }
+
+    fn outputs(&self) -> Interned<[JobItemName]> {
+        self.outputs
+    }
+
+    fn to_command_line(&self) -> Interned<[Interned<str>]> {
+        self.kind.to_command_line(&self.job)
+    }
+
+    fn run(
+        &self,
+        inputs: &[JobItem],
+        acquired_job: &mut AcquiredJob,
+    ) -> eyre::Result<Vec<JobItem>> {
+        self.kind.run(&self.job, inputs, acquired_job)
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct DynJob(Arc<dyn DynJobTrait>);
+
+impl DynJob {
+    pub fn kind_type_id(&self) -> TypeId {
+        self.0.kind_type_id()
+    }
+    pub fn downcast<T: JobKind>(&self) -> Option<(&T, &T::Job)> {
+        let inner::DynJob { kind, job, .. } = self.0.as_any().downcast_ref()?;
+        Some((kind, job))
+    }
+    pub fn kind(&self) -> DynJobKind {
+        DynJobTrait::kind(&*self.0)
+    }
+    pub fn inputs(&self) -> Interned<[JobItemName]> {
+        DynJobTrait::inputs(&*self.0)
+    }
+    pub fn outputs(&self) -> Interned<[JobItemName]> {
+        DynJobTrait::outputs(&*self.0)
+    }
+    pub fn to_command_line(&self) -> Interned<[Interned<str>]> {
+        DynJobTrait::to_command_line(&*self.0)
+    }
+    pub fn run(
+        &self,
+        inputs: &[JobItem],
+        acquired_job: &mut AcquiredJob,
+    ) -> eyre::Result<Vec<JobItem>> {
+        DynJobTrait::run(&*self.0, inputs, acquired_job)
+    }
+}
+
+impl Eq for DynJob {}
+
+impl PartialEq for DynJob {
+    fn eq(&self, other: &Self) -> bool {
+        DynJobTrait::eq_dyn(&*self.0, &*other.0)
+    }
+}
+
+impl Hash for DynJob {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        DynJobTrait::hash_dyn(&*self.0, state);
+    }
+}
+
+#[derive(Serialize, Deserialize)]
+#[serde(rename = "DynJob")]
+struct DynJobSerde {
+    kind: DynJobKind,
+    command_line: Interned<[Interned<str>]>,
+}
+
+impl Serialize for DynJob {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        DynJobSerde {
+            kind: self.kind(),
+            command_line: self.to_command_line(),
+        }
+        .serialize(serializer)
+    }
+}
+
+impl<'de> Deserialize<'de> for DynJob {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let DynJobSerde { kind, command_line } = Deserialize::deserialize(deserializer)?;
+        kind.parse_command_line(command_line)
+            .map_err(D::Error::custom)
+    }
+}
+
+#[derive(Clone, Debug)]
+enum JobGraphNode {
+    Job(DynJob),
+    Item(#[allow(dead_code, reason = "used for Debug")] JobItemName),
+}
+
+type JobGraphInner = DiGraph<JobGraphNode, ()>;
+
+#[derive(Clone, Default)]
+pub struct JobGraph {
+    jobs: HashMap<DynJob, <JobGraphInner as GraphBase>::NodeId>,
+    items: HashMap<JobItemName, <JobGraphInner as GraphBase>::NodeId>,
+    graph: JobGraphInner,
+    topological_order: Vec<<JobGraphInner as GraphBase>::NodeId>,
+    space: DfsSpace<<JobGraphInner as GraphBase>::NodeId, <JobGraphInner as Visitable>::Map>,
+}
+
+impl fmt::Debug for JobGraph {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self {
+            jobs: _,
+            items: _,
+            graph,
+            topological_order,
+            space: _,
+        } = self;
+        f.debug_struct("JobGraph")
+            .field("graph", graph)
+            .field("topological_order", topological_order)
+            .finish_non_exhaustive()
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct CycleError {
+    pub job: DynJob,
+    pub output: JobItemName,
+}
+
+impl std::error::Error for CycleError {}
+
+impl fmt::Display for CycleError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self { job, output } = self;
+        write!(
+            f,
+            "adding job to job graph would introduce a cyclic dependency through job output:\n\
+            {output:?}\n\
+            job:\n{job:?}",
+        )
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+enum EscapeForUnixShellState {
+    DollarSingleQuote,
+    SingleQuote,
+    Unquoted,
+}
+
+#[derive(Clone)]
+pub struct EscapeForUnixShell<'a> {
+    state: EscapeForUnixShellState,
+    prefix: [u8; 3],
+    bytes: &'a [u8],
+}
+
+impl<'a> fmt::Debug for EscapeForUnixShell<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl<'a> fmt::Display for EscapeForUnixShell<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for c in self.clone() {
+            f.write_char(c)?;
+        }
+        Ok(())
+    }
+}
+
+impl<'a> EscapeForUnixShell<'a> {
+    pub fn new(s: &'a str) -> Self {
+        Self::from_bytes(s.as_bytes())
+    }
+    fn make_prefix(bytes: &[u8]) -> [u8; 3] {
+        let mut prefix = [0; 3];
+        prefix[..bytes.len()].copy_from_slice(bytes);
+        prefix
+    }
+    pub fn from_bytes(bytes: &'a [u8]) -> Self {
+        let mut needs_single_quote = bytes.is_empty();
+        for &b in bytes {
+            match b {
+                b'!' | b'\'' | b'\"' | b' ' => needs_single_quote = true,
+                0..0x20 | 0x7F.. => {
+                    return Self {
+                        state: EscapeForUnixShellState::DollarSingleQuote,
+                        prefix: Self::make_prefix(b"$'"),
+                        bytes,
+                    };
+                }
+                _ => {}
+            }
+        }
+        if needs_single_quote {
+            Self {
+                state: EscapeForUnixShellState::SingleQuote,
+                prefix: Self::make_prefix(b"'"),
+                bytes,
+            }
+        } else {
+            Self {
+                state: EscapeForUnixShellState::Unquoted,
+                prefix: Self::make_prefix(b""),
+                bytes,
+            }
+        }
+    }
+}
+
+impl Iterator for EscapeForUnixShell<'_> {
+    type Item = char;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match &mut self.prefix {
+            [0, 0, 0] => {}
+            [0, 0, v] | // find first
+            [0, v, _] | // non-zero byte
+            [v, _, _] => {
+                let retval = *v as char;
+                *v = 0;
+                return Some(retval);
+            }
+        }
+        let Some(&next_byte) = self.bytes.split_off_first() else {
+            return match self.state {
+                EscapeForUnixShellState::DollarSingleQuote
+                | EscapeForUnixShellState::SingleQuote => {
+                    self.state = EscapeForUnixShellState::Unquoted;
+                    Some('\'')
+                }
+                EscapeForUnixShellState::Unquoted => None,
+            };
+        };
+        match self.state {
+            EscapeForUnixShellState::DollarSingleQuote => match next_byte {
+                b'\'' | b'\\' => {
+                    self.prefix = Self::make_prefix(&[next_byte]);
+                    Some('\\')
+                }
+                b'\t' => {
+                    self.prefix = Self::make_prefix(b"t");
+                    Some('\\')
+                }
+                b'\n' => {
+                    self.prefix = Self::make_prefix(b"n");
+                    Some('\\')
+                }
+                b'\r' => {
+                    self.prefix = Self::make_prefix(b"r");
+                    Some('\\')
+                }
+                0x20..=0x7E => Some(next_byte as char),
+                _ => {
+                    self.prefix = [
+                        b'x',
+                        char::from_digit(next_byte as u32 >> 4, 0x10).expect("known to be in range")
+                            as u8,
+                        char::from_digit(next_byte as u32 & 0xF, 0x10)
+                            .expect("known to be in range") as u8,
+                    ];
+                    Some('\\')
+                }
+            },
+            EscapeForUnixShellState::SingleQuote => {
+                if next_byte == b'\'' {
+                    self.prefix = Self::make_prefix(b"\\''");
+                    Some('\'')
+                } else {
+                    Some(next_byte as char)
+                }
+            }
+            EscapeForUnixShellState::Unquoted => match next_byte {
+                b' ' | b'!' | b'"' | b'#' | b'$' | b'&' | b'\'' | b'(' | b')' | b'*' | b','
+                | b';' | b'<' | b'>' | b'?' | b'[' | b'\\' | b']' | b'^' | b'`' | b'{' | b'|'
+                | b'}' | b'~' => {
+                    self.prefix = Self::make_prefix(&[next_byte]);
+                    Some('\\')
+                }
+                _ => Some(next_byte as char),
+            },
+        }
+    }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[non_exhaustive]
+pub enum UnixMakefileEscapeKind {
+    NonRecipe,
+    RecipeWithoutShellEscaping,
+    RecipeWithShellEscaping,
+}
+
+#[derive(Copy, Clone)]
+pub struct EscapeForUnixMakefile<'a> {
+    s: &'a str,
+    kind: UnixMakefileEscapeKind,
+}
+
+impl<'a> fmt::Debug for EscapeForUnixMakefile<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl<'a> fmt::Display for EscapeForUnixMakefile<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.do_write(f, fmt::Write::write_str, fmt::Write::write_char, |_, _| {
+            Ok(())
+        })
+    }
+}
+
+impl<'a> EscapeForUnixMakefile<'a> {
+    fn do_write<S: ?Sized, E>(
+        &self,
+        state: &mut S,
+        write_str: impl Fn(&mut S, &str) -> Result<(), E>,
+        write_char: impl Fn(&mut S, char) -> Result<(), E>,
+        add_variable: impl Fn(&mut S, &'static str) -> Result<(), E>,
+    ) -> Result<(), E> {
+        let escape_recipe_char = |c| match c {
+            '$' => write_str(state, "$$"),
+            '\0'..='\x1F' | '\x7F' => {
+                panic!("can't escape a control character for Unix Makefile: {c:?}");
+            }
+            _ => write_char(state, c),
+        };
+        match self.kind {
+            UnixMakefileEscapeKind::NonRecipe => self.s.chars().try_for_each(|c| match c {
+                '=' => {
+                    add_variable(state, "EQUALS = =")?;
+                    write_str(state, "$(EQUALS)")
+                }
+                ';' => panic!("can't escape a semicolon (;) for Unix Makefile"),
+                '$' => write_str(state, "$$"),
+                '\\' | ' ' | '#' | ':' | '%' | '*' | '?' | '[' | ']' | '~' => {
+                    write_char(state, '\\')?;
+                    write_char(state, c)
+                }
+                '\0'..='\x1F' | '\x7F' => {
+                    panic!("can't escape a control character for Unix Makefile: {c:?}");
+                }
+                _ => write_char(state, c),
+            }),
+            UnixMakefileEscapeKind::RecipeWithoutShellEscaping => {
+                self.s.chars().try_for_each(escape_recipe_char)
+            }
+            UnixMakefileEscapeKind::RecipeWithShellEscaping => {
+                EscapeForUnixShell::new(self.s).try_for_each(escape_recipe_char)
+            }
+        }
+    }
+    pub fn new(
+        s: &'a str,
+        kind: UnixMakefileEscapeKind,
+        needed_variables: &mut BTreeSet<&'static str>,
+    ) -> Self {
+        let retval = Self { s, kind };
+        let Ok(()) = retval.do_write(
+            needed_variables,
+            |_, _| Ok(()),
+            |_, _| Ok(()),
+            |needed_variables, variable| -> Result<(), std::convert::Infallible> {
+                needed_variables.insert(variable);
+                Ok(())
+            },
+        );
+        retval
+    }
+}
+
+impl JobGraph {
+    pub fn new() -> Self {
+        Self::default()
+    }
+    pub fn try_add_jobs<I: IntoIterator<Item = DynJob>>(
+        &mut self,
+        jobs: I,
+    ) -> Result<(), CycleError> {
+        let jobs = jobs.into_iter();
+        let mut new_nodes =
+            HashSet::with_capacity_and_hasher(jobs.size_hint().0, Default::default());
+        for job in jobs {
+            let Entry::Vacant(entry) = self.jobs.entry(job) else {
+                continue;
+            };
+            let job_node_id = self.graph.add_node(JobGraphNode::Job(entry.key().clone()));
+            new_nodes.insert(job_node_id);
+            let entry = entry.insert_entry(job_node_id);
+            for (item, is_input) in entry
+                .key()
+                .inputs()
+                .iter()
+                .zip(iter::repeat(true))
+                .chain(entry.key().outputs().iter().zip(iter::repeat(false)))
+            {
+                let item_node_id;
+                match self.items.entry(*item) {
+                    Entry::Occupied(entry) => item_node_id = *entry.get(),
+                    Entry::Vacant(entry) => {
+                        item_node_id = self.graph.add_node(JobGraphNode::Item(*item));
+                        new_nodes.insert(item_node_id);
+                        entry.insert(item_node_id);
+                    }
+                }
+                let mut source = job_node_id;
+                let mut dest = item_node_id;
+                if is_input {
+                    mem::swap(&mut source, &mut dest);
+                }
+                self.graph.add_edge(source, dest, ());
+            }
+        }
+        match toposort(&self.graph, Some(&mut self.space)) {
+            Ok(v) => {
+                self.topological_order = v;
+                Ok(())
+            }
+            Err(_) => {
+                // there's at least one cycle, find one!
+                let cycle = kosaraju_scc(&self.graph)
+                    .into_iter()
+                    .find_map(|scc| {
+                        if scc.len() <= 1 {
+                            // can't be a cycle since our graph is bipartite --
+                            // jobs only connect to items, never jobs to jobs or items to items
+                            None
+                        } else {
+                            Some(scc)
+                        }
+                    })
+                    .expect("we know there's a cycle");
+                let cycle_set = HashSet::from_iter(cycle.iter().copied());
+                let job = cycle
+                    .into_iter()
+                    .find_map(|node_id| {
+                        if let JobGraphNode::Job(job) = &self.graph[node_id] {
+                            Some(job.clone())
+                        } else {
+                            None
+                        }
+                    })
+                    .expect("a job must be part of the cycle");
+                let output = job
+                    .outputs()
+                    .into_iter()
+                    .find(|output| cycle_set.contains(&self.items[output]))
+                    .expect("an output must be part of the cycle");
+                for node in new_nodes {
+                    self.graph.remove_node(node);
+                }
+                Err(CycleError { job, output })
+            }
+        }
+    }
+    #[track_caller]
+    pub fn add_jobs<I: IntoIterator<Item = DynJob>>(&mut self, jobs: I) {
+        match self.try_add_jobs(jobs) {
+            Ok(()) => {}
+            Err(e) => panic!("error: {e}"),
+        }
+    }
+    pub fn to_unix_makefile(&self) -> String {
+        macro_rules! write_str {
+            ($s:expr, $($rest:tt)*) => {
+                String::write_fmt(&mut $s, format_args!($($rest)*)).expect("String::write_fmt can't fail")
+            };
+        }
+        let mut retval = String::new();
+        let mut needed_variables = BTreeSet::new();
+        for &node_id in &self.topological_order {
+            let JobGraphNode::Job(job) = &self.graph[node_id] else {
+                continue;
+            };
+            for (index, output) in job.outputs().into_iter().enumerate() {
+                match output {
+                    JobItemName::Module { .. } => continue,
+                    JobItemName::File { path } => {
+                        if index != 0 {
+                            retval.push_str(" ");
+                        }
+                        write_str!(
+                            retval,
+                            "{}",
+                            EscapeForUnixMakefile::new(
+                                &path,
+                                UnixMakefileEscapeKind::NonRecipe,
+                                &mut needed_variables
+                            )
+                        );
+                    }
+                }
+            }
+            retval.push_str(":");
+            for input in job.inputs() {
+                match input {
+                    JobItemName::Module { .. } => continue,
+                    JobItemName::File { path } => {
+                        write_str!(
+                            retval,
+                            " {}",
+                            EscapeForUnixMakefile::new(
+                                &path,
+                                UnixMakefileEscapeKind::NonRecipe,
+                                &mut needed_variables
+                            )
+                        );
+                    }
+                }
+            }
+            retval.push_str("\n\t");
+            for (index, arg) in job.to_command_line().into_iter().enumerate() {
+                if index != 0 {
+                    retval.push_str(" ");
+                }
+                write_str!(
+                    retval,
+                    "{}",
+                    EscapeForUnixMakefile::new(
+                        &arg,
+                        UnixMakefileEscapeKind::RecipeWithShellEscaping,
+                        &mut needed_variables
+                    )
+                );
+            }
+        }
+        if !needed_variables.is_empty() {
+            retval.insert_str(
+                0,
+                &String::from_iter(needed_variables.into_iter().map(|v| format!("{v}\n"))),
+            );
+        }
+        retval
+    }
+}
+
+impl Extend<DynJob> for JobGraph {
+    #[track_caller]
+    fn extend<T: IntoIterator<Item = DynJob>>(&mut self, iter: T) {
+        self.add_jobs(iter);
+    }
+}
+
+impl FromIterator<DynJob> for JobGraph {
+    #[track_caller]
+    fn from_iter<T: IntoIterator<Item = DynJob>>(iter: T) -> Self {
+        let mut retval = Self::new();
+        retval.add_jobs(iter);
+        retval
+    }
+}
+
+impl Serialize for JobGraph {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let mut serializer = serializer.serialize_seq(Some(self.jobs.len()))?;
+        for &node_id in &self.topological_order {
+            let JobGraphNode::Job(job) = &self.graph[node_id] else {
+                continue;
+            };
+            serializer.serialize_element(job)?;
+        }
+        serializer.end()
+    }
+}
+
+impl<'de> Deserialize<'de> for JobGraph {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let jobs = Vec::<DynJob>::deserialize(deserializer)?;
+        let mut retval = JobGraph::new();
+        retval.try_add_jobs(jobs).map_err(D::Error::custom)?;
+        Ok(retval)
+    }
+}
diff --git a/crates/fayalite/src/lib.rs b/crates/fayalite/src/lib.rs
index 932464ba..3a67c5c9 100644
--- a/crates/fayalite/src/lib.rs
+++ b/crates/fayalite/src/lib.rs
@@ -87,6 +87,7 @@ pub mod _docs;
 
 pub mod annotations;
 pub mod array;
+pub mod build;
 pub mod bundle;
 pub mod cli;
 pub mod clock;
@@ -104,6 +105,7 @@ pub mod reg;
 pub mod reset;
 pub mod sim;
 pub mod source_location;
+pub mod target;
 pub mod testing;
 pub mod ty;
 pub mod util;
diff --git a/crates/fayalite/src/target.rs b/crates/fayalite/src/target.rs
new file mode 100644
index 00000000..33ffee9a
--- /dev/null
+++ b/crates/fayalite/src/target.rs
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+use crate::{intern::Interned, util::job_server::AcquiredJob};
+use std::{
+    any::Any,
+    fmt,
+    iter::FusedIterator,
+    sync::{Arc, Mutex},
+};
+
+pub trait Peripheral: Any + Send + Sync + fmt::Debug {}
+
+pub trait Tool: Any + Send + Sync + fmt::Debug {
+    fn name(&self) -> Interned<str>;
+    fn run(&self, acquired_job: &mut AcquiredJob);
+}
+
+pub trait Target: Any + Send + Sync + fmt::Debug {
+    fn name(&self) -> Interned<str>;
+    fn peripherals(&self) -> Interned<[Interned<dyn Peripheral>]>;
+}
+
+#[derive(Clone)]
+struct TargetsMap(Vec<(Interned<str>, Interned<dyn Target>)>);
+
+impl TargetsMap {
+    fn sort(&mut self) {
+        self.0.sort_by(|(k1, _), (k2, _)| str::cmp(k1, k2));
+        self.0.dedup_by_key(|(k, _)| *k);
+    }
+    fn from_unsorted_vec(unsorted_vec: Vec<(Interned<str>, Interned<dyn Target>)>) -> Self {
+        let mut retval = Self(unsorted_vec);
+        retval.sort();
+        retval
+    }
+    fn extend_from_unsorted_slice(&mut self, additional: &[(Interned<str>, Interned<dyn Target>)]) {
+        self.0.extend_from_slice(additional);
+        self.sort();
+    }
+}
+
+impl Default for TargetsMap {
+    fn default() -> Self {
+        Self::from_unsorted_vec(vec![
+            // TODO: add default targets here
+        ])
+    }
+}
+
+fn access_targets<F: FnOnce(&mut Option<Arc<TargetsMap>>) -> R, R>(f: F) -> R {
+    static TARGETS: Mutex<Option<Arc<TargetsMap>>> = Mutex::new(None);
+    let mut targets_lock = TARGETS.lock().expect("shouldn't be poisoned");
+    f(&mut targets_lock)
+}
+
+pub fn add_targets<I: IntoIterator<Item = Interned<dyn Target>>>(additional: I) {
+    // run iterator and target methods outside of lock
+    let additional = Vec::from_iter(additional.into_iter().map(|v| (v.name(), v)));
+    access_targets(|targets| {
+        Arc::make_mut(targets.get_or_insert_default()).extend_from_unsorted_slice(&additional);
+    });
+}
+
+pub fn targets() -> TargetsSnapshot {
+    access_targets(|targets| match targets {
+        Some(targets) => TargetsSnapshot {
+            targets: targets.clone(),
+        },
+        None => {
+            let new_targets = Arc::<TargetsMap>::default();
+            *targets = Some(new_targets.clone());
+            TargetsSnapshot {
+                targets: new_targets,
+            }
+        }
+    })
+}
+
+#[derive(Clone)]
+pub struct TargetsSnapshot {
+    targets: Arc<TargetsMap>,
+}
+
+impl TargetsSnapshot {
+    pub fn get(&self, key: &str) -> Option<Interned<dyn Target>> {
+        let index = self
+            .targets
+            .0
+            .binary_search_by_key(&key, |(k, _v)| k)
+            .ok()?;
+        Some(self.targets.0[index].1)
+    }
+    pub fn iter(&self) -> TargetsIter {
+        self.into_iter()
+    }
+    pub fn len(&self) -> usize {
+        self.targets.0.len()
+    }
+}
+
+impl fmt::Debug for TargetsSnapshot {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("TargetsSnapshot ")?;
+        f.debug_map().entries(self).finish()
+    }
+}
+
+impl IntoIterator for &'_ mut TargetsSnapshot {
+    type Item = (Interned<str>, Interned<dyn Target>);
+    type IntoIter = TargetsIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.clone().into_iter()
+    }
+}
+
+impl IntoIterator for &'_ TargetsSnapshot {
+    type Item = (Interned<str>, Interned<dyn Target>);
+    type IntoIter = TargetsIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.clone().into_iter()
+    }
+}
+
+impl IntoIterator for TargetsSnapshot {
+    type Item = (Interned<str>, Interned<dyn Target>);
+    type IntoIter = TargetsIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        TargetsIter {
+            indexes: 0..self.targets.0.len(),
+            targets: self.targets,
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct TargetsIter {
+    targets: Arc<TargetsMap>,
+    indexes: std::ops::Range<usize>,
+}
+
+impl fmt::Debug for TargetsIter {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("TargetsIter ")?;
+        f.debug_map().entries(self.clone()).finish()
+    }
+}
+
+impl Iterator for TargetsIter {
+    type Item = (Interned<str>, Interned<dyn Target>);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        Some(self.targets.0[self.indexes.next()?])
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.indexes.size_hint()
+    }
+
+    fn count(self) -> usize {
+        self.indexes.len()
+    }
+
+    fn last(mut self) -> Option<Self::Item> {
+        self.next_back()
+    }
+
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        Some(self.targets.0[self.indexes.nth(n)?])
+    }
+
+    fn fold<B, F: FnMut(B, Self::Item) -> B>(self, init: B, mut f: F) -> B {
+        self.indexes
+            .fold(init, move |retval, index| f(retval, self.targets.0[index]))
+    }
+}
+
+impl FusedIterator for TargetsIter {}
+
+impl DoubleEndedIterator for TargetsIter {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        Some(self.targets.0[self.indexes.next_back()?])
+    }
+
+    fn nth_back(&mut self, n: usize) -> Option<Self::Item> {
+        Some(self.targets.0[self.indexes.nth_back(n)?])
+    }
+
+    fn rfold<B, F: FnMut(B, Self::Item) -> B>(self, init: B, mut f: F) -> B {
+        self.indexes
+            .rfold(init, move |retval, index| f(retval, self.targets.0[index]))
+    }
+}
+
+impl ExactSizeIterator for TargetsIter {
+    fn len(&self) -> usize {
+        self.indexes.len()
+    }
+}