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//! Constructs the dependency graph for compilation.
//!
//! Rust code is typically organized as a set of Cargo packages. The
//! dependencies between the packages themselves are stored in the
//! [`Resolve`] struct. However, we can't use that information as is for
//! compilation! A package typically contains several targets, or crates,
//! and these targets has inter-dependencies. For example, you need to
//! compile the `lib` target before the `bin` one, and you need to compile
//! `build.rs` before either of those.
//!
//! So, we need to lower the `Resolve`, which specifies dependencies between
//! *packages*, to a graph of dependencies between their *targets*, and this
//! is exactly what this module is doing! Well, almost exactly: another
//! complication is that we might want to compile the same target several times
//! (for example, with and without tests), so we actually build a dependency
//! graph of [`Unit`]s, which capture these properties.
use std::collections::{HashMap, HashSet};
use tracing::trace;
use crate::core::compiler::artifact::match_artifacts_kind_with_targets;
use crate::core::compiler::unit_graph::{UnitDep, UnitGraph};
use crate::core::compiler::{
CompileKind, CompileMode, CrateType, RustcTargetData, Unit, UnitInterner,
};
use crate::core::dependency::{Artifact, ArtifactTarget, DepKind};
use crate::core::profiles::{Profile, Profiles, UnitFor};
use crate::core::resolver::features::{FeaturesFor, ResolvedFeatures};
use crate::core::resolver::Resolve;
use crate::core::{Dependency, Package, PackageId, PackageSet, Target, TargetKind, Workspace};
use crate::ops::resolve_all_features;
use crate::util::interning::InternedString;
use crate::util::Config;
use crate::CargoResult;
const IS_NO_ARTIFACT_DEP: Option<&'static Artifact> = None;
/// Collection of stuff used while creating the [`UnitGraph`].
struct State<'a, 'cfg> {
ws: &'a Workspace<'cfg>,
config: &'cfg Config,
/// Stores the result of building the [`UnitGraph`].
unit_dependencies: UnitGraph,
package_set: &'a PackageSet<'cfg>,
usr_resolve: &'a Resolve,
usr_features: &'a ResolvedFeatures,
/// Like `usr_resolve` but for building standard library (`-Zbuild-std`).
std_resolve: Option<&'a Resolve>,
/// Like `usr_features` but for building standard library (`-Zbuild-std`).
std_features: Option<&'a ResolvedFeatures>,
/// `true` while generating the dependencies for the standard library.
is_std: bool,
/// The mode we are compiling in. Used for preventing from building lib thrice.
global_mode: CompileMode,
target_data: &'a RustcTargetData<'cfg>,
profiles: &'a Profiles,
interner: &'a UnitInterner,
// Units for `-Zrustdoc-scrape-examples`.
scrape_units: &'a [Unit],
/// A set of edges in `unit_dependencies` where (a, b) means that the
/// dependency from a to b was added purely because it was a dev-dependency.
/// This is used during `connect_run_custom_build_deps`.
dev_dependency_edges: HashSet<(Unit, Unit)>,
}
/// A boolean-like to indicate if a `Unit` is an artifact or not.
#[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
pub enum IsArtifact {
Yes,
No,
}
impl IsArtifact {
pub fn is_true(&self) -> bool {
matches!(self, IsArtifact::Yes)
}
}
/// Then entry point for building a dependency graph of compilation units.
///
/// You can find some information for arguments from doc of [`State`].
pub fn build_unit_dependencies<'a, 'cfg>(
ws: &'a Workspace<'cfg>,
package_set: &'a PackageSet<'cfg>,
resolve: &'a Resolve,
features: &'a ResolvedFeatures,
std_resolve: Option<&'a (Resolve, ResolvedFeatures)>,
roots: &[Unit],
scrape_units: &[Unit],
std_roots: &HashMap<CompileKind, Vec<Unit>>,
global_mode: CompileMode,
target_data: &'a RustcTargetData<'cfg>,
profiles: &'a Profiles,
interner: &'a UnitInterner,
) -> CargoResult<UnitGraph> {
if roots.is_empty() {
// If -Zbuild-std, don't attach units if there is nothing to build.
// Otherwise, other parts of the code may be confused by seeing units
// in the dep graph without a root.
return Ok(HashMap::new());
}
let (std_resolve, std_features) = match std_resolve {
Some((r, f)) => (Some(r), Some(f)),
None => (None, None),
};
let mut state = State {
ws,
config: ws.config(),
unit_dependencies: HashMap::new(),
package_set,
usr_resolve: resolve,
usr_features: features,
std_resolve,
std_features,
is_std: false,
global_mode,
target_data,
profiles,
interner,
scrape_units,
dev_dependency_edges: HashSet::new(),
};
let std_unit_deps = calc_deps_of_std(&mut state, std_roots)?;
deps_of_roots(roots, &mut state)?;
super::links::validate_links(state.resolve(), &state.unit_dependencies)?;
// Hopefully there aren't any links conflicts with the standard library?
if let Some(std_unit_deps) = std_unit_deps {
attach_std_deps(&mut state, std_roots, std_unit_deps);
}
connect_run_custom_build_deps(&mut state);
// Dependencies are used in tons of places throughout the backend, many of
// which affect the determinism of the build itself. As a result be sure
// that dependency lists are always sorted to ensure we've always got a
// deterministic output.
for list in state.unit_dependencies.values_mut() {
list.sort();
}
trace!("ALL UNIT DEPENDENCIES {:#?}", state.unit_dependencies);
Ok(state.unit_dependencies)
}
/// Compute all the dependencies for the standard library.
fn calc_deps_of_std(
state: &mut State<'_, '_>,
std_roots: &HashMap<CompileKind, Vec<Unit>>,
) -> CargoResult<Option<UnitGraph>> {
if std_roots.is_empty() {
return Ok(None);
}
// Compute dependencies for the standard library.
state.is_std = true;
for roots in std_roots.values() {
deps_of_roots(roots, state)?;
}
state.is_std = false;
Ok(Some(std::mem::take(&mut state.unit_dependencies)))
}
/// Add the standard library units to the `unit_dependencies`.
fn attach_std_deps(
state: &mut State<'_, '_>,
std_roots: &HashMap<CompileKind, Vec<Unit>>,
std_unit_deps: UnitGraph,
) {
// Attach the standard library as a dependency of every target unit.
let mut found = false;
for (unit, deps) in state.unit_dependencies.iter_mut() {
if !unit.kind.is_host() && !unit.mode.is_run_custom_build() {
deps.extend(std_roots[&unit.kind].iter().map(|unit| UnitDep {
unit: unit.clone(),
unit_for: UnitFor::new_normal(unit.kind),
extern_crate_name: unit.pkg.name(),
dep_name: None,
// TODO: Does this `public` make sense?
public: true,
noprelude: true,
}));
found = true;
}
}
// And also include the dependencies of the standard library itself. Don't
// include these if no units actually needed the standard library.
if found {
for (unit, deps) in std_unit_deps.into_iter() {
if let Some(other_unit) = state.unit_dependencies.insert(unit, deps) {
panic!("std unit collision with existing unit: {:?}", other_unit);
}
}
}
}
/// Compute all the dependencies of the given root units.
/// The result is stored in state.unit_dependencies.
fn deps_of_roots(roots: &[Unit], state: &mut State<'_, '_>) -> CargoResult<()> {
for unit in roots.iter() {
// Dependencies of tests/benches should not have `panic` set.
// We check the global test mode to see if we are running in `cargo
// test` in which case we ensure all dependencies have `panic`
// cleared, and avoid building the lib thrice (once with `panic`, once
// without, once for `--test`). In particular, the lib included for
// Doc tests and examples are `Build` mode here.
let root_compile_kind = unit.kind;
let unit_for = if unit.mode.is_any_test() || state.global_mode.is_rustc_test() {
if unit.target.proc_macro() {
// Special-case for proc-macros, which are forced to for-host
// since they need to link with the proc_macro crate.
UnitFor::new_host_test(state.config, root_compile_kind)
} else {
UnitFor::new_test(state.config, root_compile_kind)
}
} else if unit.target.is_custom_build() {
// This normally doesn't happen, except `clean` aggressively
// generates all units.
UnitFor::new_host(false, root_compile_kind)
} else if unit.target.proc_macro() {
UnitFor::new_host(true, root_compile_kind)
} else if unit.target.for_host() {
// Plugin should never have panic set.
UnitFor::new_compiler(root_compile_kind)
} else {
UnitFor::new_normal(root_compile_kind)
};
deps_of(unit, state, unit_for)?;
}
Ok(())
}
/// Compute the dependencies of a single unit, recursively computing all
/// transitive dependencies.
///
/// The result is stored in `state.unit_dependencies`.
fn deps_of(unit: &Unit, state: &mut State<'_, '_>, unit_for: UnitFor) -> CargoResult<()> {
// Currently the `unit_dependencies` map does not include `unit_for`. This should
// be safe for now. `TestDependency` only exists to clear the `panic`
// flag, and you'll never ask for a `unit` with `panic` set as a
// `TestDependency`. `CustomBuild` should also be fine since if the
// requested unit's settings are the same as `Any`, `CustomBuild` can't
// affect anything else in the hierarchy.
if !state.unit_dependencies.contains_key(unit) {
let unit_deps = compute_deps(unit, state, unit_for)?;
state
.unit_dependencies
.insert(unit.clone(), unit_deps.clone());
for unit_dep in unit_deps {
deps_of(&unit_dep.unit, state, unit_dep.unit_for)?;
}
}
Ok(())
}
/// Returns the direct unit dependencies for the given `Unit`.
fn compute_deps(
unit: &Unit,
state: &mut State<'_, '_>,
unit_for: UnitFor,
) -> CargoResult<Vec<UnitDep>> {
if unit.mode.is_run_custom_build() {
return compute_deps_custom_build(unit, unit_for, state);
} else if unit.mode.is_doc() {
// Note: this does not include doc test.
return compute_deps_doc(unit, state, unit_for);
}
let mut ret = Vec::new();
let mut dev_deps = Vec::new();
for (dep_pkg_id, deps) in state.deps(unit, unit_for) {
let Some(dep_lib) = calc_artifact_deps(unit, unit_for, dep_pkg_id, &deps, state, &mut ret)?
else {
continue;
};
let dep_pkg = state.get(dep_pkg_id);
let mode = check_or_build_mode(unit.mode, dep_lib);
let dep_unit_for = unit_for.with_dependency(unit, dep_lib, unit_for.root_compile_kind());
let start = ret.len();
if state.config.cli_unstable().dual_proc_macros
&& dep_lib.proc_macro()
&& !unit.kind.is_host()
{
let unit_dep = new_unit_dep(
state,
unit,
dep_pkg,
dep_lib,
dep_unit_for,
unit.kind,
mode,
IS_NO_ARTIFACT_DEP,
)?;
ret.push(unit_dep);
let unit_dep = new_unit_dep(
state,
unit,
dep_pkg,
dep_lib,
dep_unit_for,
CompileKind::Host,
mode,
IS_NO_ARTIFACT_DEP,
)?;
ret.push(unit_dep);
} else {
let unit_dep = new_unit_dep(
state,
unit,
dep_pkg,
dep_lib,
dep_unit_for,
unit.kind.for_target(dep_lib),
mode,
IS_NO_ARTIFACT_DEP,
)?;
ret.push(unit_dep);
}
// If the unit added was a dev-dependency unit, then record that in the
// dev-dependencies array. We'll add this to
// `state.dev_dependency_edges` at the end and process it later in
// `connect_run_custom_build_deps`.
if deps.iter().all(|d| !d.is_transitive()) {
for dep in ret[start..].iter() {
dev_deps.push((unit.clone(), dep.unit.clone()));
}
}
}
state.dev_dependency_edges.extend(dev_deps);
// If this target is a build script, then what we've collected so far is
// all we need. If this isn't a build script, then it depends on the
// build script if there is one.
if unit.target.is_custom_build() {
return Ok(ret);
}
ret.extend(dep_build_script(unit, unit_for, state)?);
// If this target is a binary, test, example, etc, then it depends on
// the library of the same package. The call to `resolve.deps` above
// didn't include `pkg` in the return values, so we need to special case
// it here and see if we need to push `(pkg, pkg_lib_target)`.
if unit.target.is_lib() && unit.mode != CompileMode::Doctest {
return Ok(ret);
}
ret.extend(maybe_lib(unit, state, unit_for)?);
// If any integration tests/benches are being run, make sure that
// binaries are built as well.
if !unit.mode.is_check()
&& unit.mode.is_any_test()
&& (unit.target.is_test() || unit.target.is_bench())
{
let id = unit.pkg.package_id();
ret.extend(
unit.pkg
.targets()
.iter()
.filter(|t| {
// Skip binaries with required features that have not been selected.
match t.required_features() {
Some(rf) if t.is_bin() => {
let features = resolve_all_features(
state.resolve(),
state.features(),
state.package_set,
id,
);
rf.iter().all(|f| features.contains(f))
}
None if t.is_bin() => true,
_ => false,
}
})
.map(|t| {
new_unit_dep(
state,
unit,
&unit.pkg,
t,
UnitFor::new_normal(unit_for.root_compile_kind()),
unit.kind.for_target(t),
CompileMode::Build,
IS_NO_ARTIFACT_DEP,
)
})
.collect::<CargoResult<Vec<UnitDep>>>()?,
);
}
Ok(ret)
}
/// Find artifacts for all `deps` of `unit` and add units that build these artifacts
/// to `ret`.
fn calc_artifact_deps<'a>(
unit: &Unit,
unit_for: UnitFor,
dep_id: PackageId,
deps: &[&Dependency],
state: &State<'a, '_>,
ret: &mut Vec<UnitDep>,
) -> CargoResult<Option<&'a Target>> {
let mut has_artifact_lib = false;
let mut maybe_non_artifact_lib = false;
let artifact_pkg = state.get(dep_id);
for dep in deps {
let Some(artifact) = dep.artifact() else {
maybe_non_artifact_lib = true;
continue;
};
has_artifact_lib |= artifact.is_lib();
// Custom build scripts (build/compile) never get artifact dependencies,
// but the run-build-script step does (where it is handled).
if !unit.target.is_custom_build() {
debug_assert!(
!unit.mode.is_run_custom_build(),
"BUG: This should be handled in a separate branch"
);
ret.extend(artifact_targets_to_unit_deps(
unit,
unit_for.with_artifact_features(artifact),
state,
artifact
.target()
.and_then(|t| match t {
ArtifactTarget::BuildDependencyAssumeTarget => None,
ArtifactTarget::Force(kind) => Some(CompileKind::Target(kind)),
})
.unwrap_or(unit.kind),
artifact_pkg,
dep,
)?);
}
}
if has_artifact_lib || maybe_non_artifact_lib {
Ok(artifact_pkg.targets().iter().find(|t| t.is_lib()))
} else {
Ok(None)
}
}
/// Returns the dependencies needed to run a build script.
///
/// The `unit` provided must represent an execution of a build script, and
/// the returned set of units must all be run before `unit` is run.
fn compute_deps_custom_build(
unit: &Unit,
unit_for: UnitFor,
state: &State<'_, '_>,
) -> CargoResult<Vec<UnitDep>> {
if let Some(links) = unit.pkg.manifest().links() {
if state
.target_data
.script_override(links, unit.kind)
.is_some()
{
// Overridden build scripts don't have any dependencies.
return Ok(Vec::new());
}
}
// All dependencies of this unit should use profiles for custom builds.
// If this is a build script of a proc macro, make sure it uses host
// features.
let script_unit_for = unit_for.for_custom_build();
// When not overridden, then the dependencies to run a build script are:
//
// 1. Compiling the build script itself.
// 2. For each immediate dependency of our package which has a `links`
// key, the execution of that build script.
//
// We don't have a great way of handling (2) here right now so this is
// deferred until after the graph of all unit dependencies has been
// constructed.
let compile_script_unit = new_unit_dep(
state,
unit,
&unit.pkg,
&unit.target,
script_unit_for,
// Build scripts always compiled for the host.
CompileKind::Host,
CompileMode::Build,
IS_NO_ARTIFACT_DEP,
)?;
let mut result = vec![compile_script_unit];
// Include any artifact dependencies.
//
// This is essentially the same as `calc_artifact_deps`, but there are some
// subtle differences that require this to be implemented differently.
//
// Produce units that build all required artifact kinds (like binaries,
// static libraries, etc) with the correct compile target.
//
// Computing the compile target for artifact units is more involved as it has to handle
// various target configurations specific to artifacts, like `target = "target"` and
// `target = "<triple>"`, which makes knowing the root units compile target
// `root_unit_compile_target` necessary.
let root_unit_compile_target = unit_for.root_compile_kind();
let unit_for = UnitFor::new_host(/*host_features*/ true, root_unit_compile_target);
for (dep_pkg_id, deps) in state.deps(unit, script_unit_for) {
for dep in deps {
if dep.kind() != DepKind::Build || dep.artifact().is_none() {
continue;
}
let artifact_pkg = state.get(dep_pkg_id);
let artifact = dep.artifact().expect("artifact dep");
let resolved_artifact_compile_kind = artifact
.target()
.map(|target| target.to_resolved_compile_kind(root_unit_compile_target));
result.extend(artifact_targets_to_unit_deps(
unit,
unit_for.with_artifact_features_from_resolved_compile_kind(
resolved_artifact_compile_kind,
),
state,
resolved_artifact_compile_kind.unwrap_or(CompileKind::Host),
artifact_pkg,
dep,
)?);
}
}
Ok(result)
}
/// Given a `parent` unit containing a dependency `dep` whose package is `artifact_pkg`,
/// find all targets in `artifact_pkg` which refer to the `dep`s artifact declaration
/// and turn them into units.
/// Due to the nature of artifact dependencies, a single dependency in a manifest can
/// cause one or more targets to be build, for instance with
/// `artifact = ["bin:a", "bin:b", "staticlib"]`, which is very different from normal
/// dependencies which cause only a single unit to be created.
///
/// `compile_kind` is the computed kind for the future artifact unit
/// dependency, only the caller can pick the correct one.
fn artifact_targets_to_unit_deps(
parent: &Unit,
parent_unit_for: UnitFor,
state: &State<'_, '_>,
compile_kind: CompileKind,
artifact_pkg: &Package,
dep: &Dependency,
) -> CargoResult<Vec<UnitDep>> {
let ret =
match_artifacts_kind_with_targets(dep, artifact_pkg.targets(), parent.pkg.name().as_str())?
.into_iter()
.map(|(_artifact_kind, target)| target)
.flat_map(|target| {
// We split target libraries into individual units, even though rustc is able
// to produce multiple kinds in an single invocation for the sole reason that
// each artifact kind has its own output directory, something we can't easily
// teach rustc for now.
match target.kind() {
TargetKind::Lib(kinds) => Box::new(
kinds
.iter()
.filter(|tk| matches!(tk, CrateType::Cdylib | CrateType::Staticlib))
.map(|target_kind| {
new_unit_dep(
state,
parent,
artifact_pkg,
target
.clone()
.set_kind(TargetKind::Lib(vec![target_kind.clone()])),
parent_unit_for,
compile_kind,
CompileMode::Build,
dep.artifact(),
)
}),
) as Box<dyn Iterator<Item = _>>,
_ => Box::new(std::iter::once(new_unit_dep(
state,
parent,
artifact_pkg,
target,
parent_unit_for,
compile_kind,
CompileMode::Build,
dep.artifact(),
))),
}
})
.collect::<Result<Vec<_>, _>>()?;
Ok(ret)
}
/// Returns the dependencies necessary to document a package.
fn compute_deps_doc(
unit: &Unit,
state: &mut State<'_, '_>,
unit_for: UnitFor,
) -> CargoResult<Vec<UnitDep>> {
// To document a library, we depend on dependencies actually being
// built. If we're documenting *all* libraries, then we also depend on
// the documentation of the library being built.
let mut ret = Vec::new();
for (id, deps) in state.deps(unit, unit_for) {
let Some(dep_lib) = calc_artifact_deps(unit, unit_for, id, &deps, state, &mut ret)? else {
continue;
};
let dep_pkg = state.get(id);
// Rustdoc only needs rmeta files for regular dependencies.
// However, for plugins/proc macros, deps should be built like normal.
let mode = check_or_build_mode(unit.mode, dep_lib);
let dep_unit_for = unit_for.with_dependency(unit, dep_lib, unit_for.root_compile_kind());
let lib_unit_dep = new_unit_dep(
state,
unit,
dep_pkg,
dep_lib,
dep_unit_for,
unit.kind.for_target(dep_lib),
mode,
IS_NO_ARTIFACT_DEP,
)?;
ret.push(lib_unit_dep);
if dep_lib.documented() {
if let CompileMode::Doc { deps: true } = unit.mode {
// Document this lib as well.
let doc_unit_dep = new_unit_dep(
state,
unit,
dep_pkg,
dep_lib,
dep_unit_for,
unit.kind.for_target(dep_lib),
unit.mode,
IS_NO_ARTIFACT_DEP,
)?;
ret.push(doc_unit_dep);
}
}
}
// Be sure to build/run the build script for documented libraries.
ret.extend(dep_build_script(unit, unit_for, state)?);
// If we document a binary/example, we need the library available.
if unit.target.is_bin() || unit.target.is_example() {
// build the lib
ret.extend(maybe_lib(unit, state, unit_for)?);
// and also the lib docs for intra-doc links
if let Some(lib) = unit
.pkg
.targets()
.iter()
.find(|t| t.is_linkable() && t.documented())
{
let dep_unit_for = unit_for.with_dependency(unit, lib, unit_for.root_compile_kind());
let lib_doc_unit = new_unit_dep(
state,
unit,
&unit.pkg,
lib,
dep_unit_for,
unit.kind.for_target(lib),
unit.mode,
IS_NO_ARTIFACT_DEP,
)?;
ret.push(lib_doc_unit);
}
}
// Add all units being scraped for examples as a dependency of top-level Doc units.
if state.ws.unit_needs_doc_scrape(unit) {
for scrape_unit in state.scrape_units.iter() {
let scrape_unit_for = UnitFor::new_normal(scrape_unit.kind);
deps_of(scrape_unit, state, scrape_unit_for)?;
ret.push(new_unit_dep(
state,
scrape_unit,
&scrape_unit.pkg,
&scrape_unit.target,
scrape_unit_for,
scrape_unit.kind,
scrape_unit.mode,
IS_NO_ARTIFACT_DEP,
)?);
}
}
Ok(ret)
}
fn maybe_lib(
unit: &Unit,
state: &mut State<'_, '_>,
unit_for: UnitFor,
) -> CargoResult<Option<UnitDep>> {
unit.pkg
.targets()
.iter()
.find(|t| t.is_linkable())
.map(|t| {
let mode = check_or_build_mode(unit.mode, t);
let dep_unit_for = unit_for.with_dependency(unit, t, unit_for.root_compile_kind());
new_unit_dep(
state,
unit,
&unit.pkg,
t,
dep_unit_for,
unit.kind.for_target(t),
mode,
IS_NO_ARTIFACT_DEP,
)
})
.transpose()
}
/// If a build script is scheduled to be run for the package specified by
/// `unit`, this function will return the unit to run that build script.
///
/// Overriding a build script simply means that the running of the build
/// script itself doesn't have any dependencies, so even in that case a unit
/// of work is still returned. `None` is only returned if the package has no
/// build script.
fn dep_build_script(
unit: &Unit,
unit_for: UnitFor,
state: &State<'_, '_>,
) -> CargoResult<Option<UnitDep>> {
unit.pkg
.targets()
.iter()
.find(|t| t.is_custom_build())
.map(|t| {
// The profile stored in the Unit is the profile for the thing
// the custom build script is running for.
let profile = state.profiles.get_profile_run_custom_build(&unit.profile);
// UnitFor::for_custom_build is used because we want the `host` flag set
// for all of our build dependencies (so they all get
// build-override profiles), including compiling the build.rs
// script itself.
//
// If `is_for_host_features` here is `false`, that means we are a
// build.rs script for a normal dependency and we want to set the
// CARGO_FEATURE_* environment variables to the features as a
// normal dep.
//
// If `is_for_host_features` here is `true`, that means that this
// package is being used as a build dependency or proc-macro, and
// so we only want to set CARGO_FEATURE_* variables for the host
// side of the graph.
//
// Keep in mind that the RunCustomBuild unit and the Compile
// build.rs unit use the same features. This is because some
// people use `cfg!` and `#[cfg]` expressions to check for enabled
// features instead of just checking `CARGO_FEATURE_*` at runtime.
// In the case with the new feature resolver (decoupled host
// deps), and a shared dependency has different features enabled
// for normal vs. build, then the build.rs script will get
// compiled twice. I believe it is not feasible to only build it
// once because it would break a large number of scripts (they
// would think they have the wrong set of features enabled).
let script_unit_for = unit_for.for_custom_build();
new_unit_dep_with_profile(
state,
unit,
&unit.pkg,
t,
script_unit_for,
unit.kind,
CompileMode::RunCustomBuild,
profile,
IS_NO_ARTIFACT_DEP,
)
})
.transpose()
}
/// Choose the correct mode for dependencies.
fn check_or_build_mode(mode: CompileMode, target: &Target) -> CompileMode {
match mode {
CompileMode::Check { .. } | CompileMode::Doc { .. } | CompileMode::Docscrape => {
if target.for_host() {
// Plugin and proc macro targets should be compiled like
// normal.
CompileMode::Build
} else {
// Regular dependencies should not be checked with --test.
// Regular dependencies of doc targets should emit rmeta only.
CompileMode::Check { test: false }
}
}
_ => CompileMode::Build,
}
}
/// Create a new Unit for a dependency from `parent` to `pkg` and `target`.
fn new_unit_dep(
state: &State<'_, '_>,
parent: &Unit,
pkg: &Package,
target: &Target,
unit_for: UnitFor,
kind: CompileKind,
mode: CompileMode,
artifact: Option<&Artifact>,
) -> CargoResult<UnitDep> {
let is_local = pkg.package_id().source_id().is_path() && !state.is_std;
let profile = state.profiles.get_profile(
pkg.package_id(),
state.ws.is_member(pkg),
is_local,
unit_for,
kind,
);
new_unit_dep_with_profile(
state, parent, pkg, target, unit_for, kind, mode, profile, artifact,
)
}
fn new_unit_dep_with_profile(
state: &State<'_, '_>,
parent: &Unit,
pkg: &Package,
target: &Target,
unit_for: UnitFor,
kind: CompileKind,
mode: CompileMode,
profile: Profile,
artifact: Option<&Artifact>,
) -> CargoResult<UnitDep> {
let (extern_crate_name, dep_name) = state.resolve().extern_crate_name_and_dep_name(
parent.pkg.package_id(),
pkg.package_id(),
target,
)?;
let public = state
.resolve()
.is_public_dep(parent.pkg.package_id(), pkg.package_id());
let features_for = unit_for.map_to_features_for(artifact);
let artifact_target = match features_for {
FeaturesFor::ArtifactDep(target) => Some(target),
_ => None,
};
let features = state.activated_features(pkg.package_id(), features_for);
let unit = state.interner.intern(
pkg,
target,
profile,
kind,
mode,
features,
state.is_std,
/*dep_hash*/ 0,
artifact.map_or(IsArtifact::No, |_| IsArtifact::Yes),
artifact_target,
);
Ok(UnitDep {
unit,
unit_for,
extern_crate_name,
dep_name,
public,
noprelude: false,
})
}
/// Fill in missing dependencies for units of the `RunCustomBuild`
///
/// As mentioned above in `compute_deps_custom_build` each build script
/// execution has two dependencies. The first is compiling the build script
/// itself (already added) and the second is that all crates the package of the
/// build script depends on with `links` keys, their build script execution. (a
/// bit confusing eh?)
///
/// Here we take the entire `deps` map and add more dependencies from execution
/// of one build script to execution of another build script.
fn connect_run_custom_build_deps(state: &mut State<'_, '_>) {
let mut new_deps = Vec::new();
{
let state = &*state;
// First up build a reverse dependency map. This is a mapping of all
// `RunCustomBuild` known steps to the unit which depends on them. For
// example a library might depend on a build script, so this map will
// have the build script as the key and the library would be in the
// value's set.
let mut reverse_deps_map = HashMap::new();
for (unit, deps) in state.unit_dependencies.iter() {
for dep in deps {
if dep.unit.mode == CompileMode::RunCustomBuild {
reverse_deps_map
.entry(dep.unit.clone())
.or_insert_with(HashSet::new)
.insert(unit);
}
}
}
// Next, we take a look at all build scripts executions listed in the
// dependency map. Our job here is to take everything that depends on
// this build script (from our reverse map above) and look at the other
// package dependencies of these parents.
//
// If we depend on a linkable target and the build script mentions
// `links`, then we depend on that package's build script! Here we use
// `dep_build_script` to manufacture an appropriate build script unit to
// depend on.
for unit in state
.unit_dependencies
.keys()
.filter(|k| k.mode == CompileMode::RunCustomBuild)
{
// This list of dependencies all depend on `unit`, an execution of
// the build script.
let Some(reverse_deps) = reverse_deps_map.get(unit) else {
continue;
};
let to_add = reverse_deps
.iter()
// Get all sibling dependencies of `unit`
.flat_map(|reverse_dep| {
state.unit_dependencies[reverse_dep]
.iter()
.map(move |a| (reverse_dep, a))
})
// Only deps with `links`.
.filter(|(_parent, other)| {
other.unit.pkg != unit.pkg
&& other.unit.target.is_linkable()
&& other.unit.pkg.manifest().links().is_some()
})
// Avoid cycles when using the doc --scrape-examples feature:
// Say a workspace has crates A and B where A has a build-dependency on B.
// The Doc units for A and B will have a dependency on the Docscrape for both A and B.
// So this would add a dependency from B-build to A-build, causing a cycle:
// B (build) -> A (build) -> B(build)
// See the test scrape_examples_avoid_build_script_cycle for a concrete example.
// To avoid this cycle, we filter out the B -> A (docscrape) dependency.
.filter(|(_parent, other)| !other.unit.mode.is_doc_scrape())
// Skip dependencies induced via dev-dependencies since
// connections between `links` and build scripts only happens
// via normal dependencies. Otherwise since dev-dependencies can
// be cyclic we could have cyclic build-script executions.
.filter_map(move |(parent, other)| {
if state
.dev_dependency_edges
.contains(&((*parent).clone(), other.unit.clone()))
{
None
} else {
Some(other)
}
})
// Get the RunCustomBuild for other lib.
.filter_map(|other| {
state.unit_dependencies[&other.unit]
.iter()
.find(|other_dep| other_dep.unit.mode == CompileMode::RunCustomBuild)
.cloned()
})
.collect::<HashSet<_>>();
if !to_add.is_empty() {
// (RunCustomBuild, set(other RunCustomBuild))
new_deps.push((unit.clone(), to_add));
}
}
}
// And finally, add in all the missing dependencies!
for (unit, new_deps) in new_deps {
state
.unit_dependencies
.get_mut(&unit)
.unwrap()
.extend(new_deps);
}
}
impl<'a, 'cfg> State<'a, 'cfg> {
/// Gets `std_resolve` during building std, otherwise `usr_resolve`.
fn resolve(&self) -> &'a Resolve {
if self.is_std {
self.std_resolve.unwrap()
} else {
self.usr_resolve
}
}
/// Gets `std_features` during building std, otherwise `usr_features`.
fn features(&self) -> &'a ResolvedFeatures {
if self.is_std {
self.std_features.unwrap()
} else {
self.usr_features
}
}
fn activated_features(
&self,
pkg_id: PackageId,
features_for: FeaturesFor,
) -> Vec<InternedString> {
let features = self.features();
features.activated_features(pkg_id, features_for)
}
fn is_dep_activated(
&self,
pkg_id: PackageId,
features_for: FeaturesFor,
dep_name: InternedString,
) -> bool {
self.features()
.is_dep_activated(pkg_id, features_for, dep_name)
}
fn get(&self, id: PackageId) -> &'a Package {
self.package_set
.get_one(id)
.unwrap_or_else(|_| panic!("expected {} to be downloaded", id))
}
/// Returns a filtered set of dependencies for the given unit.
fn deps(&self, unit: &Unit, unit_for: UnitFor) -> Vec<(PackageId, Vec<&Dependency>)> {
let pkg_id = unit.pkg.package_id();
let kind = unit.kind;
self.resolve()
.deps(pkg_id)
.filter_map(|(id, deps)| {
assert!(!deps.is_empty());
let deps: Vec<_> = deps
.iter()
.filter(|dep| {
// If this target is a build command, then we only want build
// dependencies, otherwise we want everything *other than* build
// dependencies.
if unit.target.is_custom_build() != dep.is_build() {
return false;
}
// If this dependency is **not** a transitive dependency, then it
// only applies to test/example targets.
if !dep.is_transitive()
&& !unit.target.is_test()
&& !unit.target.is_example()
&& !unit.mode.is_any_test()
{
return false;
}
// If this dependency is only available for certain platforms,
// make sure we're only enabling it for that platform.
if !self.target_data.dep_platform_activated(dep, kind) {
return false;
}
// If this is an optional dependency, and the new feature resolver
// did not enable it, don't include it.
if dep.is_optional() {
// This `unit_for` is from parent dep and *SHOULD* contains its own
// artifact dep information inside `artifact_target_for_features`.
// So, no need to map any artifact info from an incorrect `dep.artifact()`.
let features_for = unit_for.map_to_features_for(IS_NO_ARTIFACT_DEP);
if !self.is_dep_activated(pkg_id, features_for, dep.name_in_toml()) {
return false;
}
}
// If we've gotten past all that, then this dependency is
// actually used!
true
})
.collect();
if deps.is_empty() {
None
} else {
Some((id, deps))
}
})
.collect()
}
}