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//! # Interact with the compiler
//!
//! If you consider [`ops::cargo_compile::compile`] as a `rustc` driver but on
//! Cargo side, this module is kinda the `rustc_interface` for that merits.
//! It contains all the interaction between Cargo and the rustc compiler,
//! from preparing the context for the entire build process, to scheduling
//! and executing each unit of work (e.g. running `rustc`), to managing and
//! caching the output artifact of a build.
//!
//! However, it hasn't yet exposed a clear definition of each phase or session,
//! like what rustc has done[^1]. Also, no one knows if Cargo really needs that.
//! To be pragmatic, here we list a handful of items you may want to learn:
//!
//! * [`BuildContext`] is a static context containing all information you need
//! before a build gets started.
//! * [`Context`] is the center of the world, coordinating a running build and
//! collecting information from it.
//! * [`custom_build`] is the home of build script executions and output parsing.
//! * [`fingerprint`] not only defines but also executes a set of rules to
//! determine if a re-compile is needed.
//! * [`job_queue`] is where the parallelism, job scheduling, and communication
//! machinery happen between Cargo and the compiler.
//! * [`layout`] defines and manages output artifacts of a build in the filesystem.
//! * [`unit_dependencies`] is for building a dependency graph for compilation
//! from a result of dependency resolution.
//! * [`Unit`] contains sufficient information to build something, usually
//! turning into a compiler invocation in a later phase.
//!
//! [^1]: Maybe [`-Zbuild-plan`](https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#build-plan)
//! was designed to serve that purpose but still [in flux](https://github.com/rust-lang/cargo/issues/7614).
//!
//! [`ops::cargo_compile::compile`]: crate::ops::compile
pub mod artifact;
mod build_config;
pub(crate) mod build_context;
mod build_plan;
mod compilation;
mod compile_kind;
pub(crate) mod context;
mod crate_type;
mod custom_build;
pub(crate) mod fingerprint;
pub mod future_incompat;
pub(crate) mod job_queue;
pub(crate) mod layout;
mod links;
mod lto;
mod output_depinfo;
pub mod rustdoc;
pub mod standard_lib;
mod timings;
mod unit;
pub mod unit_dependencies;
pub mod unit_graph;
use std::collections::{HashMap, HashSet};
use std::env;
use std::ffi::{OsStr, OsString};
use std::fmt::Display;
use std::fs::{self, File};
use std::io::{BufRead, Write};
use std::path::{Path, PathBuf};
use std::sync::Arc;
use anyhow::{Context as _, Error};
use lazycell::LazyCell;
use tracing::{debug, trace};
pub use self::build_config::{BuildConfig, CompileMode, MessageFormat, TimingOutput};
pub use self::build_context::{
BuildContext, FileFlavor, FileType, RustDocFingerprint, RustcTargetData, TargetInfo,
};
use self::build_plan::BuildPlan;
pub use self::compilation::{Compilation, Doctest, UnitOutput};
pub use self::compile_kind::{CompileKind, CompileTarget};
pub use self::context::{Context, Metadata};
pub use self::crate_type::CrateType;
pub use self::custom_build::LinkArgTarget;
pub use self::custom_build::{BuildOutput, BuildScriptOutputs, BuildScripts};
pub(crate) use self::fingerprint::DirtyReason;
pub use self::job_queue::Freshness;
use self::job_queue::{Job, JobQueue, JobState, Work};
pub(crate) use self::layout::Layout;
pub use self::lto::Lto;
use self::output_depinfo::output_depinfo;
use self::unit_graph::UnitDep;
use crate::core::compiler::future_incompat::FutureIncompatReport;
pub use crate::core::compiler::unit::{Unit, UnitInterner};
use crate::core::manifest::TargetSourcePath;
use crate::core::profiles::{PanicStrategy, Profile, Strip};
use crate::core::{Feature, PackageId, Target, Verbosity};
use crate::util::errors::{CargoResult, VerboseError};
use crate::util::interning::InternedString;
use crate::util::machine_message::{self, Message};
use crate::util::toml::TomlDebugInfo;
use crate::util::{add_path_args, internal, iter_join_onto, profile};
use cargo_util::{paths, ProcessBuilder, ProcessError};
use rustfix::diagnostics::Applicability;
const RUSTDOC_CRATE_VERSION_FLAG: &str = "--crate-version";
/// A glorified callback for executing calls to rustc. Rather than calling rustc
/// directly, we'll use an `Executor`, giving clients an opportunity to intercept
/// the build calls.
pub trait Executor: Send + Sync + 'static {
/// Called after a rustc process invocation is prepared up-front for a given
/// unit of work (may still be modified for runtime-known dependencies, when
/// the work is actually executed).
fn init(&self, _cx: &Context<'_, '_>, _unit: &Unit) {}
/// In case of an `Err`, Cargo will not continue with the build process for
/// this package.
fn exec(
&self,
cmd: &ProcessBuilder,
id: PackageId,
target: &Target,
mode: CompileMode,
on_stdout_line: &mut dyn FnMut(&str) -> CargoResult<()>,
on_stderr_line: &mut dyn FnMut(&str) -> CargoResult<()>,
) -> CargoResult<()>;
/// Queried when queuing each unit of work. If it returns true, then the
/// unit will always be rebuilt, independent of whether it needs to be.
fn force_rebuild(&self, _unit: &Unit) -> bool {
false
}
}
/// A `DefaultExecutor` calls rustc without doing anything else. It is Cargo's
/// default behaviour.
#[derive(Copy, Clone)]
pub struct DefaultExecutor;
impl Executor for DefaultExecutor {
fn exec(
&self,
cmd: &ProcessBuilder,
_id: PackageId,
_target: &Target,
_mode: CompileMode,
on_stdout_line: &mut dyn FnMut(&str) -> CargoResult<()>,
on_stderr_line: &mut dyn FnMut(&str) -> CargoResult<()>,
) -> CargoResult<()> {
cmd.exec_with_streaming(on_stdout_line, on_stderr_line, false)
.map(drop)
}
}
/// Builds up and enqueue a list of pending jobs onto the `job` queue.
///
/// Starting from the `unit`, this function recursively calls itself to build
/// all jobs for dependencies of the `unit`. Each of these jobs represents
/// compiling a particular package.
///
/// Note that **no actual work is executed as part of this**, that's all done
/// next as part of [`JobQueue::execute`] function which will run everything
/// in order with proper parallelism.
fn compile<'cfg>(
cx: &mut Context<'_, 'cfg>,
jobs: &mut JobQueue<'cfg>,
plan: &mut BuildPlan,
unit: &Unit,
exec: &Arc<dyn Executor>,
force_rebuild: bool,
) -> CargoResult<()> {
let bcx = cx.bcx;
let build_plan = bcx.build_config.build_plan;
if !cx.compiled.insert(unit.clone()) {
return Ok(());
}
// Build up the work to be done to compile this unit, enqueuing it once
// we've got everything constructed.
let p = profile::start(format!("preparing: {}/{}", unit.pkg, unit.target.name()));
fingerprint::prepare_init(cx, unit)?;
let job = if unit.mode.is_run_custom_build() {
custom_build::prepare(cx, unit)?
} else if unit.mode.is_doc_test() {
// We run these targets later, so this is just a no-op for now.
Job::new_fresh()
} else if build_plan {
Job::new_dirty(rustc(cx, unit, &exec.clone())?, None)
} else {
let force = exec.force_rebuild(unit) || force_rebuild;
let mut job = fingerprint::prepare_target(cx, unit, force)?;
job.before(if job.freshness().is_dirty() {
let work = if unit.mode.is_doc() || unit.mode.is_doc_scrape() {
rustdoc(cx, unit)?
} else {
rustc(cx, unit, exec)?
};
work.then(link_targets(cx, unit, false)?)
} else {
// We always replay the output cache,
// since it might contain future-incompat-report messages
let work = replay_output_cache(
unit.pkg.package_id(),
PathBuf::from(unit.pkg.manifest_path()),
&unit.target,
cx.files().message_cache_path(unit),
cx.bcx.build_config.message_format,
unit.show_warnings(bcx.config),
);
// Need to link targets on both the dirty and fresh.
work.then(link_targets(cx, unit, true)?)
});
job
};
jobs.enqueue(cx, unit, job)?;
drop(p);
// Be sure to compile all dependencies of this target as well.
let deps = Vec::from(cx.unit_deps(unit)); // Create vec due to mutable borrow.
for dep in deps {
compile(cx, jobs, plan, &dep.unit, exec, false)?;
}
if build_plan {
plan.add(cx, unit)?;
}
Ok(())
}
/// Generates the warning message used when fallible doc-scrape units fail,
/// either for rustdoc or rustc.
fn make_failed_scrape_diagnostic(
cx: &Context<'_, '_>,
unit: &Unit,
top_line: impl Display,
) -> String {
let manifest_path = unit.pkg.manifest_path();
let relative_manifest_path = manifest_path
.strip_prefix(cx.bcx.ws.root())
.unwrap_or(&manifest_path);
format!(
"\
{top_line}
Try running with `--verbose` to see the error message.
If an example should not be scanned, then consider adding `doc-scrape-examples = false` to its `[[example]]` definition in {}",
relative_manifest_path.display()
)
}
/// Creates a unit of work invoking `rustc` for building the `unit`.
fn rustc(cx: &mut Context<'_, '_>, unit: &Unit, exec: &Arc<dyn Executor>) -> CargoResult<Work> {
let mut rustc = prepare_rustc(cx, unit)?;
let build_plan = cx.bcx.build_config.build_plan;
let name = unit.pkg.name();
let buildkey = unit.buildkey();
let outputs = cx.outputs(unit)?;
let root = cx.files().out_dir(unit);
// Prepare the native lib state (extra `-L` and `-l` flags).
let build_script_outputs = Arc::clone(&cx.build_script_outputs);
let current_id = unit.pkg.package_id();
let manifest_path = PathBuf::from(unit.pkg.manifest_path());
let build_scripts = cx.build_scripts.get(unit).cloned();
// If we are a binary and the package also contains a library, then we
// don't pass the `-l` flags.
let pass_l_flag = unit.target.is_lib() || !unit.pkg.targets().iter().any(|t| t.is_lib());
let dep_info_name = if cx.files().use_extra_filename(unit) {
format!(
"{}-{}.d",
unit.target.crate_name(),
cx.files().metadata(unit)
)
} else {
format!("{}.d", unit.target.crate_name())
};
let rustc_dep_info_loc = root.join(dep_info_name);
let dep_info_loc = fingerprint::dep_info_loc(cx, unit);
let mut output_options = OutputOptions::new(cx, unit);
let package_id = unit.pkg.package_id();
let target = Target::clone(&unit.target);
let mode = unit.mode;
exec.init(cx, unit);
let exec = exec.clone();
let root_output = cx.files().host_dest().to_path_buf();
let target_dir = cx.bcx.ws.target_dir().into_path_unlocked();
let pkg_root = unit.pkg.root().to_path_buf();
let cwd = rustc
.get_cwd()
.unwrap_or_else(|| cx.bcx.config.cwd())
.to_path_buf();
let fingerprint_dir = cx.files().fingerprint_dir(unit);
let script_metadata = cx.find_build_script_metadata(unit);
let is_local = unit.is_local();
let artifact = unit.artifact;
let hide_diagnostics_for_scrape_unit = cx.bcx.unit_can_fail_for_docscraping(unit)
&& !matches!(cx.bcx.config.shell().verbosity(), Verbosity::Verbose);
let failed_scrape_diagnostic = hide_diagnostics_for_scrape_unit.then(|| {
// If this unit is needed for doc-scraping, then we generate a diagnostic that
// describes the set of reverse-dependencies that cause the unit to be needed.
let target_desc = unit.target.description_named();
let mut for_scrape_units = cx
.bcx
.scrape_units_have_dep_on(unit)
.into_iter()
.map(|unit| unit.target.description_named())
.collect::<Vec<_>>();
for_scrape_units.sort();
let for_scrape_units = for_scrape_units.join(", ");
make_failed_scrape_diagnostic(cx, unit, format_args!("failed to check {target_desc} in package `{name}` as a prerequisite for scraping examples from: {for_scrape_units}"))
});
if hide_diagnostics_for_scrape_unit {
output_options.show_diagnostics = false;
}
return Ok(Work::new(move |state| {
// Artifacts are in a different location than typical units,
// hence we must assure the crate- and target-dependent
// directory is present.
if artifact.is_true() {
paths::create_dir_all(&root)?;
}
// Only at runtime have we discovered what the extra -L and -l
// arguments are for native libraries, so we process those here. We
// also need to be sure to add any -L paths for our plugins to the
// dynamic library load path as a plugin's dynamic library may be
// located somewhere in there.
// Finally, if custom environment variables have been produced by
// previous build scripts, we include them in the rustc invocation.
if let Some(build_scripts) = build_scripts {
let script_outputs = build_script_outputs.lock().unwrap();
if !build_plan {
add_native_deps(
&mut rustc,
&script_outputs,
&build_scripts,
pass_l_flag,
&target,
current_id,
)?;
add_plugin_deps(&mut rustc, &script_outputs, &build_scripts, &root_output)?;
}
add_custom_flags(&mut rustc, &script_outputs, script_metadata)?;
}
for output in outputs.iter() {
// If there is both an rmeta and rlib, rustc will prefer to use the
// rlib, even if it is older. Therefore, we must delete the rlib to
// force using the new rmeta.
if output.path.extension() == Some(OsStr::new("rmeta")) {
let dst = root.join(&output.path).with_extension("rlib");
if dst.exists() {
paths::remove_file(&dst)?;
}
}
// Some linkers do not remove the executable, but truncate and modify it.
// That results in the old hard-link being modified even after renamed.
// We delete the old artifact here to prevent this behavior from confusing users.
// See rust-lang/cargo#8348.
if output.hardlink.is_some() && output.path.exists() {
_ = paths::remove_file(&output.path).map_err(|e| {
tracing::debug!(
"failed to delete previous output file `{:?}`: {e:?}",
output.path
);
});
}
}
fn verbose_if_simple_exit_code(err: Error) -> Error {
// If a signal on unix (`code == None`) or an abnormal termination
// on Windows (codes like `0xC0000409`), don't hide the error details.
match err
.downcast_ref::<ProcessError>()
.as_ref()
.and_then(|perr| perr.code)
{
Some(n) if cargo_util::is_simple_exit_code(n) => VerboseError::new(err).into(),
_ => err,
}
}
state.running(&rustc);
let timestamp = paths::set_invocation_time(&fingerprint_dir)?;
if build_plan {
state.build_plan(buildkey, rustc.clone(), outputs.clone());
} else {
let result = exec
.exec(
&rustc,
package_id,
&target,
mode,
&mut |line| on_stdout_line(state, line, package_id, &target),
&mut |line| {
on_stderr_line(
state,
line,
package_id,
&manifest_path,
&target,
&mut output_options,
)
},
)
.map_err(verbose_if_simple_exit_code)
.with_context(|| {
// adapted from rustc_errors/src/lib.rs
let warnings = match output_options.warnings_seen {
0 => String::new(),
1 => "; 1 warning emitted".to_string(),
count => format!("; {} warnings emitted", count),
};
let errors = match output_options.errors_seen {
0 => String::new(),
1 => " due to previous error".to_string(),
count => format!(" due to {} previous errors", count),
};
let name = descriptive_pkg_name(&name, &target, &mode);
format!("could not compile {name}{errors}{warnings}")
});
if let Err(e) = result {
if let Some(diagnostic) = failed_scrape_diagnostic {
state.warning(diagnostic)?;
}
return Err(e);
}
// Exec should never return with success *and* generate an error.
debug_assert_eq!(output_options.errors_seen, 0);
}
if rustc_dep_info_loc.exists() {
fingerprint::translate_dep_info(
&rustc_dep_info_loc,
&dep_info_loc,
&cwd,
&pkg_root,
&target_dir,
&rustc,
// Do not track source files in the fingerprint for registry dependencies.
is_local,
)
.with_context(|| {
internal(format!(
"could not parse/generate dep info at: {}",
rustc_dep_info_loc.display()
))
})?;
// This mtime shift allows Cargo to detect if a source file was
// modified in the middle of the build.
paths::set_file_time_no_err(dep_info_loc, timestamp);
}
Ok(())
}));
// Add all relevant `-L` and `-l` flags from dependencies (now calculated and
// present in `state`) to the command provided.
fn add_native_deps(
rustc: &mut ProcessBuilder,
build_script_outputs: &BuildScriptOutputs,
build_scripts: &BuildScripts,
pass_l_flag: bool,
target: &Target,
current_id: PackageId,
) -> CargoResult<()> {
for key in build_scripts.to_link.iter() {
let output = build_script_outputs.get(key.1).ok_or_else(|| {
internal(format!(
"couldn't find build script output for {}/{}",
key.0, key.1
))
})?;
for path in output.library_paths.iter() {
rustc.arg("-L").arg(path);
}
if key.0 == current_id {
if pass_l_flag {
for name in output.library_links.iter() {
rustc.arg("-l").arg(name);
}
}
}
for (lt, arg) in &output.linker_args {
// There was an unintentional change where cdylibs were
// allowed to be passed via transitive dependencies. This
// clause should have been kept in the `if` block above. For
// now, continue allowing it for cdylib only.
// See https://github.com/rust-lang/cargo/issues/9562
if lt.applies_to(target) && (key.0 == current_id || *lt == LinkArgTarget::Cdylib) {
rustc.arg("-C").arg(format!("link-arg={}", arg));
}
}
}
Ok(())
}
}
/// Link the compiled target (often of form `foo-{metadata_hash}`) to the
/// final target. This must happen during both "Fresh" and "Compile".
fn link_targets(cx: &mut Context<'_, '_>, unit: &Unit, fresh: bool) -> CargoResult<Work> {
let bcx = cx.bcx;
let outputs = cx.outputs(unit)?;
let export_dir = cx.files().export_dir();
let package_id = unit.pkg.package_id();
let manifest_path = PathBuf::from(unit.pkg.manifest_path());
let profile = unit.profile.clone();
let unit_mode = unit.mode;
let features = unit.features.iter().map(|s| s.to_string()).collect();
let json_messages = bcx.build_config.emit_json();
let executable = cx.get_executable(unit)?;
let mut target = Target::clone(&unit.target);
if let TargetSourcePath::Metabuild = target.src_path() {
// Give it something to serialize.
let path = unit.pkg.manifest().metabuild_path(cx.bcx.ws.target_dir());
target.set_src_path(TargetSourcePath::Path(path));
}
Ok(Work::new(move |state| {
// If we're a "root crate", e.g., the target of this compilation, then we
// hard link our outputs out of the `deps` directory into the directory
// above. This means that `cargo build` will produce binaries in
// `target/debug` which one probably expects.
let mut destinations = vec![];
for output in outputs.iter() {
let src = &output.path;
// This may have been a `cargo rustc` command which changes the
// output, so the source may not actually exist.
if !src.exists() {
continue;
}
let Some(dst) = output.hardlink.as_ref() else {
destinations.push(src.clone());
continue;
};
destinations.push(dst.clone());
paths::link_or_copy(src, dst)?;
if let Some(ref path) = output.export_path {
let export_dir = export_dir.as_ref().unwrap();
paths::create_dir_all(export_dir)?;
paths::link_or_copy(src, path)?;
}
}
if json_messages {
let debuginfo = match profile.debuginfo.into_inner() {
TomlDebugInfo::None => machine_message::ArtifactDebuginfo::Int(0),
TomlDebugInfo::Limited => machine_message::ArtifactDebuginfo::Int(1),
TomlDebugInfo::Full => machine_message::ArtifactDebuginfo::Int(2),
TomlDebugInfo::LineDirectivesOnly => {
machine_message::ArtifactDebuginfo::Named("line-directives-only")
}
TomlDebugInfo::LineTablesOnly => {
machine_message::ArtifactDebuginfo::Named("line-tables-only")
}
};
let art_profile = machine_message::ArtifactProfile {
opt_level: profile.opt_level.as_str(),
debuginfo: Some(debuginfo),
debug_assertions: profile.debug_assertions,
overflow_checks: profile.overflow_checks,
test: unit_mode.is_any_test(),
};
let msg = machine_message::Artifact {
package_id,
manifest_path,
target: &target,
profile: art_profile,
features,
filenames: destinations,
executable,
fresh,
}
.to_json_string();
state.stdout(msg)?;
}
Ok(())
}))
}
// For all plugin dependencies, add their -L paths (now calculated and present
// in `build_script_outputs`) to the dynamic library load path for the command
// to execute.
fn add_plugin_deps(
rustc: &mut ProcessBuilder,
build_script_outputs: &BuildScriptOutputs,
build_scripts: &BuildScripts,
root_output: &Path,
) -> CargoResult<()> {
let var = paths::dylib_path_envvar();
let search_path = rustc.get_env(var).unwrap_or_default();
let mut search_path = env::split_paths(&search_path).collect::<Vec<_>>();
for (pkg_id, metadata) in &build_scripts.plugins {
let output = build_script_outputs
.get(*metadata)
.ok_or_else(|| internal(format!("couldn't find libs for plugin dep {}", pkg_id)))?;
search_path.append(&mut filter_dynamic_search_path(
output.library_paths.iter(),
root_output,
));
}
let search_path = paths::join_paths(&search_path, var)?;
rustc.env(var, &search_path);
Ok(())
}
// Determine paths to add to the dynamic search path from -L entries
//
// Strip off prefixes like "native=" or "framework=" and filter out directories
// **not** inside our output directory since they are likely spurious and can cause
// clashes with system shared libraries (issue #3366).
fn filter_dynamic_search_path<'a, I>(paths: I, root_output: &Path) -> Vec<PathBuf>
where
I: Iterator<Item = &'a PathBuf>,
{
let mut search_path = vec![];
for dir in paths {
let dir = match dir.to_str().and_then(|s| s.split_once("=")) {
Some(("native" | "crate" | "dependency" | "framework" | "all", path)) => path.into(),
_ => dir.clone(),
};
if dir.starts_with(&root_output) {
search_path.push(dir);
} else {
debug!(
"Not including path {} in runtime library search path because it is \
outside target root {}",
dir.display(),
root_output.display()
);
}
}
search_path
}
/// Prepares flags and environments we can compute for a `rustc` invocation
/// before the job queue starts compiling any unit.
///
/// This builds a static view of the invocation. Flags depending on the
/// completion of other units will be added later in runtime, such as flags
/// from build scripts.
fn prepare_rustc(cx: &Context<'_, '_>, unit: &Unit) -> CargoResult<ProcessBuilder> {
let is_primary = cx.is_primary_package(unit);
let is_workspace = cx.bcx.ws.is_member(&unit.pkg);
let mut base = cx
.compilation
.rustc_process(unit, is_primary, is_workspace)?;
if is_primary {
base.env("CARGO_PRIMARY_PACKAGE", "1");
}
if unit.target.is_test() || unit.target.is_bench() {
let tmp = cx.files().layout(unit.kind).prepare_tmp()?;
base.env("CARGO_TARGET_TMPDIR", tmp.display().to_string());
}
base.inherit_jobserver(&cx.jobserver);
build_base_args(cx, &mut base, unit)?;
build_deps_args(&mut base, cx, unit)?;
add_cap_lints(cx.bcx, unit, &mut base);
base.args(cx.bcx.rustflags_args(unit));
if cx.bcx.config.cli_unstable().binary_dep_depinfo {
base.arg("-Z").arg("binary-dep-depinfo");
}
Ok(base)
}
/// Prepares flags and environments we can compute for a `rustdoc` invocation
/// before the job queue starts compiling any unit.
///
/// This builds a static view of the invocation. Flags depending on the
/// completion of other units will be added later in runtime, such as flags
/// from build scripts.
fn prepare_rustdoc(cx: &Context<'_, '_>, unit: &Unit) -> CargoResult<ProcessBuilder> {
let bcx = cx.bcx;
// script_metadata is not needed here, it is only for tests.
let mut rustdoc = cx.compilation.rustdoc_process(unit, None)?;
rustdoc.inherit_jobserver(&cx.jobserver);
let crate_name = unit.target.crate_name();
rustdoc.arg("--crate-name").arg(&crate_name);
add_path_args(bcx.ws, unit, &mut rustdoc);
add_cap_lints(bcx, unit, &mut rustdoc);
if let CompileKind::Target(target) = unit.kind {
rustdoc.arg("--target").arg(target.rustc_target());
}
let doc_dir = cx.files().out_dir(unit);
rustdoc.arg("-o").arg(&doc_dir);
rustdoc.args(&features_args(unit));
rustdoc.args(&check_cfg_args(cx, unit));
add_error_format_and_color(cx, &mut rustdoc);
add_allow_features(cx, &mut rustdoc);
rustdoc.args(unit.pkg.manifest().lint_rustflags());
if let Some(args) = cx.bcx.extra_args_for(unit) {
rustdoc.args(args);
}
let metadata = cx.metadata_for_doc_units[unit];
rustdoc.arg("-C").arg(format!("metadata={}", metadata));
if unit.mode.is_doc_scrape() {
debug_assert!(cx.bcx.scrape_units.contains(unit));
if unit.target.is_test() {
rustdoc.arg("--scrape-tests");
}
rustdoc.arg("-Zunstable-options");
rustdoc
.arg("--scrape-examples-output-path")
.arg(scrape_output_path(cx, unit)?);
// Only scrape example for items from crates in the workspace, to reduce generated file size
for pkg in cx.bcx.ws.members() {
let names = pkg
.targets()
.iter()
.map(|target| target.crate_name())
.collect::<HashSet<_>>();
for name in names {
rustdoc.arg("--scrape-examples-target-crate").arg(name);
}
}
}
if should_include_scrape_units(cx.bcx, unit) {
rustdoc.arg("-Zunstable-options");
}
build_deps_args(&mut rustdoc, cx, unit)?;
rustdoc::add_root_urls(cx, unit, &mut rustdoc)?;
rustdoc.args(bcx.rustdocflags_args(unit));
if !crate_version_flag_already_present(&rustdoc) {
append_crate_version_flag(unit, &mut rustdoc);
}
Ok(rustdoc)
}
/// Creates a unit of work invoking `rustdoc` for documenting the `unit`.
fn rustdoc(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Work> {
let mut rustdoc = prepare_rustdoc(cx, unit)?;
let crate_name = unit.target.crate_name();
let doc_dir = cx.files().out_dir(unit);
// Create the documentation directory ahead of time as rustdoc currently has
// a bug where concurrent invocations will race to create this directory if
// it doesn't already exist.
paths::create_dir_all(&doc_dir)?;
let target_desc = unit.target.description_named();
let name = unit.pkg.name();
let build_script_outputs = Arc::clone(&cx.build_script_outputs);
let package_id = unit.pkg.package_id();
let manifest_path = PathBuf::from(unit.pkg.manifest_path());
let target = Target::clone(&unit.target);
let mut output_options = OutputOptions::new(cx, unit);
let script_metadata = cx.find_build_script_metadata(unit);
let scrape_outputs = if should_include_scrape_units(cx.bcx, unit) {
Some(
cx.bcx
.scrape_units
.iter()
.map(|unit| Ok((cx.files().metadata(unit), scrape_output_path(cx, unit)?)))
.collect::<CargoResult<HashMap<_, _>>>()?,
)
} else {
None
};
let failed_scrape_units = Arc::clone(&cx.failed_scrape_units);
let hide_diagnostics_for_scrape_unit = cx.bcx.unit_can_fail_for_docscraping(unit)
&& !matches!(cx.bcx.config.shell().verbosity(), Verbosity::Verbose);
let failed_scrape_diagnostic = hide_diagnostics_for_scrape_unit.then(|| {
make_failed_scrape_diagnostic(
cx,
unit,
format_args!("failed to scan {target_desc} in package `{name}` for example code usage"),
)
});
if hide_diagnostics_for_scrape_unit {
output_options.show_diagnostics = false;
}
Ok(Work::new(move |state| {
add_custom_flags(
&mut rustdoc,
&build_script_outputs.lock().unwrap(),
script_metadata,
)?;
// Add the output of scraped examples to the rustdoc command.
// This action must happen after the unit's dependencies have finished,
// because some of those deps may be Docscrape units which have failed.
// So we dynamically determine which `--with-examples` flags to pass here.
if let Some(scrape_outputs) = scrape_outputs {
let failed_scrape_units = failed_scrape_units.lock().unwrap();
for (metadata, output_path) in &scrape_outputs {
if !failed_scrape_units.contains(metadata) {
rustdoc.arg("--with-examples").arg(output_path);
}
}
}
let crate_dir = doc_dir.join(&crate_name);
if crate_dir.exists() {
// Remove output from a previous build. This ensures that stale
// files for removed items are removed.
debug!("removing pre-existing doc directory {:?}", crate_dir);
paths::remove_dir_all(crate_dir)?;
}
state.running(&rustdoc);
let result = rustdoc
.exec_with_streaming(
&mut |line| on_stdout_line(state, line, package_id, &target),
&mut |line| {
on_stderr_line(
state,
line,
package_id,
&manifest_path,
&target,
&mut output_options,
)
},
false,
)
.with_context(|| format!("could not document `{}`", name));
if let Err(e) = result {
if let Some(diagnostic) = failed_scrape_diagnostic {
state.warning(diagnostic)?;
}
return Err(e);
}
Ok(())
}))
}
// The --crate-version flag could have already been passed in RUSTDOCFLAGS
// or as an extra compiler argument for rustdoc
fn crate_version_flag_already_present(rustdoc: &ProcessBuilder) -> bool {
rustdoc.get_args().any(|flag| {
flag.to_str()
.map_or(false, |flag| flag.starts_with(RUSTDOC_CRATE_VERSION_FLAG))
})
}
fn append_crate_version_flag(unit: &Unit, rustdoc: &mut ProcessBuilder) {
rustdoc
.arg(RUSTDOC_CRATE_VERSION_FLAG)
.arg(unit.pkg.version().to_string());
}
/// Adds [`--cap-lints`] to the command to execute.
///
/// [`--cap-lints`]: https://doc.rust-lang.org/nightly/rustc/lints/levels.html#capping-lints
fn add_cap_lints(bcx: &BuildContext<'_, '_>, unit: &Unit, cmd: &mut ProcessBuilder) {
// If this is an upstream dep we don't want warnings from, turn off all
// lints.
if !unit.show_warnings(bcx.config) {
cmd.arg("--cap-lints").arg("allow");
// If this is an upstream dep but we *do* want warnings, make sure that they
// don't fail compilation.
} else if !unit.is_local() {
cmd.arg("--cap-lints").arg("warn");
}
}
/// Forwards [`-Zallow-features`] if it is set for cargo.
///
/// [`-Zallow-features`]: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#allow-features
fn add_allow_features(cx: &Context<'_, '_>, cmd: &mut ProcessBuilder) {
if let Some(allow) = &cx.bcx.config.cli_unstable().allow_features {
let mut arg = String::from("-Zallow-features=");
let _ = iter_join_onto(&mut arg, allow, ",");
cmd.arg(&arg);
}
}
/// Adds [`--error-format`] to the command to execute.
///
/// Cargo always uses JSON output. This has several benefits, such as being
/// easier to parse, handles changing formats (for replaying cached messages),
/// ensures atomic output (so messages aren't interleaved), allows for
/// intercepting messages like rmeta artifacts, etc. rustc includes a
/// "rendered" field in the JSON message with the message properly formatted,
/// which Cargo will extract and display to the user.
///
/// [`--error-format`]: https://doc.rust-lang.org/nightly/rustc/command-line-arguments.html#--error-format-control-how-errors-are-produced
fn add_error_format_and_color(cx: &Context<'_, '_>, cmd: &mut ProcessBuilder) {
cmd.arg("--error-format=json");
let mut json = String::from("--json=diagnostic-rendered-ansi,artifacts,future-incompat");
match cx.bcx.build_config.message_format {
MessageFormat::Short | MessageFormat::Json { short: true, .. } => {
json.push_str(",diagnostic-short");
}
_ => {}
}
cmd.arg(json);
let config = cx.bcx.config;
if let Some(width) = config.shell().err_width().diagnostic_terminal_width() {
cmd.arg(format!("--diagnostic-width={width}"));
}
}
/// Adds essential rustc flags and environment variables to the command to execute.
fn build_base_args(cx: &Context<'_, '_>, cmd: &mut ProcessBuilder, unit: &Unit) -> CargoResult<()> {
assert!(!unit.mode.is_run_custom_build());
let bcx = cx.bcx;
let Profile {
ref opt_level,
codegen_backend,
codegen_units,
debuginfo,
debug_assertions,
split_debuginfo,
overflow_checks,
rpath,
ref panic,
incremental,
strip,
rustflags: profile_rustflags,
..
} = unit.profile.clone();
let test = unit.mode.is_any_test();
cmd.arg("--crate-name").arg(&unit.target.crate_name());
let edition = unit.target.edition();
edition.cmd_edition_arg(cmd);
add_path_args(bcx.ws, unit, cmd);
add_error_format_and_color(cx, cmd);
add_allow_features(cx, cmd);
let mut contains_dy_lib = false;
if !test {
for crate_type in &unit.target.rustc_crate_types() {
cmd.arg("--crate-type").arg(crate_type.as_str());
contains_dy_lib |= crate_type == &CrateType::Dylib;
}
}
if unit.mode.is_check() {
cmd.arg("--emit=dep-info,metadata");
} else if !unit.requires_upstream_objects() {
// Always produce metadata files for rlib outputs. Metadata may be used
// in this session for a pipelined compilation, or it may be used in a
// future Cargo session as part of a pipelined compile.
cmd.arg("--emit=dep-info,metadata,link");
} else {
cmd.arg("--emit=dep-info,link");
}
let prefer_dynamic = (unit.target.for_host() && !unit.target.is_custom_build())
|| (contains_dy_lib && !cx.is_primary_package(unit));
if prefer_dynamic {
cmd.arg("-C").arg("prefer-dynamic");
}
if opt_level.as_str() != "0" {
cmd.arg("-C").arg(&format!("opt-level={}", opt_level));
}
if *panic != PanicStrategy::Unwind {
cmd.arg("-C").arg(format!("panic={}", panic));
}
cmd.args(<o_args(cx, unit));
if let Some(backend) = codegen_backend {
cmd.arg("-Z").arg(&format!("codegen-backend={}", backend));
}
if let Some(n) = codegen_units {
cmd.arg("-C").arg(&format!("codegen-units={}", n));
}
let debuginfo = debuginfo.into_inner();
// Shorten the number of arguments if possible.
if debuginfo != TomlDebugInfo::None {
cmd.arg("-C").arg(format!("debuginfo={debuginfo}"));
// This is generally just an optimization on build time so if we don't
// pass it then it's ok. The values for the flag (off, packed, unpacked)
// may be supported or not depending on the platform, so availability is
// checked per-value. For example, at the time of writing this code, on
// Windows the only stable valid value for split-debuginfo is "packed",
// while on Linux "unpacked" is also stable.
if let Some(split) = split_debuginfo {
if cx
.bcx
.target_data
.info(unit.kind)
.supports_debuginfo_split(split)
{
cmd.arg("-C").arg(format!("split-debuginfo={split}"));
}
}
}
cmd.args(unit.pkg.manifest().lint_rustflags());
cmd.args(&profile_rustflags);
if let Some(args) = cx.bcx.extra_args_for(unit) {
cmd.args(args);
}
// `-C overflow-checks` is implied by the setting of `-C debug-assertions`,
// so we only need to provide `-C overflow-checks` if it differs from
// the value of `-C debug-assertions` we would provide.
if opt_level.as_str() != "0" {
if debug_assertions {
cmd.args(&["-C", "debug-assertions=on"]);
if !overflow_checks {
cmd.args(&["-C", "overflow-checks=off"]);
}
} else if overflow_checks {
cmd.args(&["-C", "overflow-checks=on"]);
}
} else if !debug_assertions {
cmd.args(&["-C", "debug-assertions=off"]);
if overflow_checks {
cmd.args(&["-C", "overflow-checks=on"]);
}
} else if !overflow_checks {
cmd.args(&["-C", "overflow-checks=off"]);
}
if test && unit.target.harness() {
cmd.arg("--test");
// Cargo has historically never compiled `--test` binaries with
// `panic=abort` because the `test` crate itself didn't support it.
// Support is now upstream, however, but requires an unstable flag to be
// passed when compiling the test. We require, in Cargo, an unstable
// flag to pass to rustc, so register that here. Eventually this flag
// will simply not be needed when the behavior is stabilized in the Rust
// compiler itself.
if *panic == PanicStrategy::Abort {
cmd.arg("-Z").arg("panic-abort-tests");
}
} else if test {
cmd.arg("--cfg").arg("test");
}
cmd.args(&features_args(unit));
cmd.args(&check_cfg_args(cx, unit));
let meta = cx.files().metadata(unit);
cmd.arg("-C").arg(&format!("metadata={}", meta));
if cx.files().use_extra_filename(unit) {
cmd.arg("-C").arg(&format!("extra-filename=-{}", meta));
}
if rpath {
cmd.arg("-C").arg("rpath");
}
cmd.arg("--out-dir").arg(&cx.files().out_dir(unit));
fn opt(cmd: &mut ProcessBuilder, key: &str, prefix: &str, val: Option<&OsStr>) {
if let Some(val) = val {
let mut joined = OsString::from(prefix);
joined.push(val);
cmd.arg(key).arg(joined);
}
}
if let CompileKind::Target(n) = unit.kind {
cmd.arg("--target").arg(n.rustc_target());
}
opt(
cmd,
"-C",
"linker=",
cx.compilation
.target_linker(unit.kind)
.as_ref()
.map(|s| s.as_ref()),
);
if incremental {
let dir = cx.files().layout(unit.kind).incremental().as_os_str();
opt(cmd, "-C", "incremental=", Some(dir));
}
if strip != Strip::None {
cmd.arg("-C").arg(format!("strip={}", strip));
}
if unit.is_std {
// -Zforce-unstable-if-unmarked prevents the accidental use of
// unstable crates within the sysroot (such as "extern crate libc" or
// any non-public crate in the sysroot).
//
// RUSTC_BOOTSTRAP allows unstable features on stable.
cmd.arg("-Z")
.arg("force-unstable-if-unmarked")
.env("RUSTC_BOOTSTRAP", "1");
}
// Add `CARGO_BIN_EXE_` environment variables for building tests.
if unit.target.is_test() || unit.target.is_bench() {
for bin_target in unit
.pkg
.manifest()
.targets()
.iter()
.filter(|target| target.is_bin())
{
let exe_path = cx
.files()
.bin_link_for_target(bin_target, unit.kind, cx.bcx)?;
let name = bin_target
.binary_filename()
.unwrap_or(bin_target.name().to_string());
let key = format!("CARGO_BIN_EXE_{}", name);
cmd.env(&key, exe_path);
}
}
Ok(())
}
/// All active features for the unit passed as `--cfg features=<feature-name>`.
fn features_args(unit: &Unit) -> Vec<OsString> {
let mut args = Vec::with_capacity(unit.features.len() * 2);
for feat in &unit.features {
args.push(OsString::from("--cfg"));
args.push(OsString::from(format!("feature=\"{}\"", feat)));
}
args
}
/// Generates the `--check-cfg` arguments for the `unit`.
/// See unstable feature [`check-cfg`].
///
/// [`check-cfg`]: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#check-cfg
fn check_cfg_args(cx: &Context<'_, '_>, unit: &Unit) -> Vec<OsString> {
if let Some((features, well_known_names, well_known_values, _output)) =
cx.bcx.config.cli_unstable().check_cfg
{
let mut args = Vec::with_capacity(unit.pkg.summary().features().len() * 2 + 4);
args.push(OsString::from("-Zunstable-options"));
if features {
// This generate something like this:
// - values(feature)
// - values(feature, "foo", "bar")
let mut arg = OsString::from("values(feature");
for (&feat, _) in unit.pkg.summary().features() {
arg.push(", \"");
arg.push(&feat);
arg.push("\"");
}
arg.push(")");
args.push(OsString::from("--check-cfg"));
args.push(arg);
}
if well_known_names {
args.push(OsString::from("--check-cfg"));
args.push(OsString::from("names()"));
}
if well_known_values {
args.push(OsString::from("--check-cfg"));
args.push(OsString::from("values()"));
}
args
} else {
Vec::new()
}
}
/// Adds LTO related codegen flags.
fn lto_args(cx: &Context<'_, '_>, unit: &Unit) -> Vec<OsString> {
let mut result = Vec::new();
let mut push = |arg: &str| {
result.push(OsString::from("-C"));
result.push(OsString::from(arg));
};
match cx.lto[unit] {
lto::Lto::Run(None) => push("lto"),
lto::Lto::Run(Some(s)) => push(&format!("lto={}", s)),
lto::Lto::Off => {
push("lto=off");
push("embed-bitcode=no");
}
lto::Lto::ObjectAndBitcode => {} // this is rustc's default
lto::Lto::OnlyBitcode => push("linker-plugin-lto"),
lto::Lto::OnlyObject => push("embed-bitcode=no"),
}
result
}
/// Adds dependency-relevant rustc flags and environment variables
/// to the command to execute, such as [`-L`] and [`--extern`].
///
/// [`-L`]: https://doc.rust-lang.org/nightly/rustc/command-line-arguments.html#-l-add-a-directory-to-the-library-search-path
/// [`--extern`]: https://doc.rust-lang.org/nightly/rustc/command-line-arguments.html#--extern-specify-where-an-external-library-is-located
fn build_deps_args(cmd: &mut ProcessBuilder, cx: &Context<'_, '_>, unit: &Unit) -> CargoResult<()> {
let bcx = cx.bcx;
cmd.arg("-L").arg(&{
let mut deps = OsString::from("dependency=");
deps.push(cx.files().deps_dir(unit));
deps
});
// Be sure that the host path is also listed. This'll ensure that proc macro
// dependencies are correctly found (for reexported macros).
if !unit.kind.is_host() {
cmd.arg("-L").arg(&{
let mut deps = OsString::from("dependency=");
deps.push(cx.files().host_deps());
deps
});
}
let deps = cx.unit_deps(unit);
// If there is not one linkable target but should, rustc fails later
// on if there is an `extern crate` for it. This may turn into a hard
// error in the future (see PR #4797).
if !deps
.iter()
.any(|dep| !dep.unit.mode.is_doc() && dep.unit.target.is_linkable())
{
if let Some(dep) = deps.iter().find(|dep| {
!dep.unit.mode.is_doc() && dep.unit.target.is_lib() && !dep.unit.artifact.is_true()
}) {
bcx.config.shell().warn(format!(
"The package `{}` \
provides no linkable target. The compiler might raise an error while compiling \
`{}`. Consider adding 'dylib' or 'rlib' to key `crate-type` in `{}`'s \
Cargo.toml. This warning might turn into a hard error in the future.",
dep.unit.target.crate_name(),
unit.target.crate_name(),
dep.unit.target.crate_name()
))?;
}
}
let mut unstable_opts = false;
for dep in deps {
if dep.unit.mode.is_run_custom_build() {
cmd.env("OUT_DIR", &cx.files().build_script_out_dir(&dep.unit));
}
}
for arg in extern_args(cx, unit, &mut unstable_opts)? {
cmd.arg(arg);
}
for (var, env) in artifact::get_env(cx, deps)? {
cmd.env(&var, env);
}
// This will only be set if we're already using a feature
// requiring nightly rust
if unstable_opts {
cmd.arg("-Z").arg("unstable-options");
}
Ok(())
}
/// Adds extra rustc flags and environment variables collected from the output
/// of a build-script to the command to execute, include custom environment
/// variables and `cfg`.
fn add_custom_flags(
cmd: &mut ProcessBuilder,
build_script_outputs: &BuildScriptOutputs,
metadata: Option<Metadata>,
) -> CargoResult<()> {
if let Some(metadata) = metadata {
if let Some(output) = build_script_outputs.get(metadata) {
for cfg in output.cfgs.iter() {
cmd.arg("--cfg").arg(cfg);
}
if !output.check_cfgs.is_empty() {
cmd.arg("-Zunstable-options");
for check_cfg in &output.check_cfgs {
cmd.arg("--check-cfg").arg(check_cfg);
}
}
for (name, value) in output.env.iter() {
cmd.env(name, value);
}
}
}
Ok(())
}
/// Generates a list of `--extern` arguments.
pub fn extern_args(
cx: &Context<'_, '_>,
unit: &Unit,
unstable_opts: &mut bool,
) -> CargoResult<Vec<OsString>> {
let mut result = Vec::new();
let deps = cx.unit_deps(unit);
// Closure to add one dependency to `result`.
let mut link_to =
|dep: &UnitDep, extern_crate_name: InternedString, noprelude: bool| -> CargoResult<()> {
let mut value = OsString::new();
let mut opts = Vec::new();
if unit
.pkg
.manifest()
.unstable_features()
.require(Feature::public_dependency())
.is_ok()
&& !dep.public
{
opts.push("priv");
*unstable_opts = true;
}
if noprelude {
opts.push("noprelude");
*unstable_opts = true;
}
if !opts.is_empty() {
value.push(opts.join(","));
value.push(":");
}
value.push(extern_crate_name.as_str());
value.push("=");
let mut pass = |file| {
let mut value = value.clone();
value.push(file);
result.push(OsString::from("--extern"));
result.push(value);
};
let outputs = cx.outputs(&dep.unit)?;
if cx.only_requires_rmeta(unit, &dep.unit) || dep.unit.mode.is_check() {
// Example: rlib dependency for an rlib, rmeta is all that is required.
let output = outputs
.iter()
.find(|output| output.flavor == FileFlavor::Rmeta)
.expect("failed to find rmeta dep for pipelined dep");
pass(&output.path);
} else {
// Example: a bin needs `rlib` for dependencies, it cannot use rmeta.
for output in outputs.iter() {
if output.flavor == FileFlavor::Linkable {
pass(&output.path);
}
}
}
Ok(())
};
for dep in deps {
if dep.unit.target.is_linkable() && !dep.unit.mode.is_doc() {
link_to(dep, dep.extern_crate_name, dep.noprelude)?;
}
}
if unit.target.proc_macro() {
// Automatically import `proc_macro`.
result.push(OsString::from("--extern"));
result.push(OsString::from("proc_macro"));
}
Ok(result)
}
fn envify(s: &str) -> String {
s.chars()
.flat_map(|c| c.to_uppercase())
.map(|c| if c == '-' { '_' } else { c })
.collect()
}
/// Configuration of the display of messages emitted by the compiler,
/// e.g. diagnostics, warnings, errors, and message caching.
struct OutputOptions {
/// What format we're emitting from Cargo itself.
format: MessageFormat,
/// Where to write the JSON messages to support playback later if the unit
/// is fresh. The file is created lazily so that in the normal case, lots
/// of empty files are not created. If this is None, the output will not
/// be cached (such as when replaying cached messages).
cache_cell: Option<(PathBuf, LazyCell<File>)>,
/// If `true`, display any diagnostics.
/// Other types of JSON messages are processed regardless
/// of the value of this flag.
///
/// This is used primarily for cache replay. If you build with `-vv`, the
/// cache will be filled with diagnostics from dependencies. When the
/// cache is replayed without `-vv`, we don't want to show them.
show_diagnostics: bool,
/// Tracks the number of warnings we've seen so far.
warnings_seen: usize,
/// Tracks the number of errors we've seen so far.
errors_seen: usize,
}
impl OutputOptions {
fn new(cx: &Context<'_, '_>, unit: &Unit) -> OutputOptions {
let path = cx.files().message_cache_path(unit);
// Remove old cache, ignore ENOENT, which is the common case.
drop(fs::remove_file(&path));
let cache_cell = Some((path, LazyCell::new()));
OutputOptions {
format: cx.bcx.build_config.message_format,
cache_cell,
show_diagnostics: true,
warnings_seen: 0,
errors_seen: 0,
}
}
}
fn on_stdout_line(
state: &JobState<'_, '_>,
line: &str,
_package_id: PackageId,
_target: &Target,
) -> CargoResult<()> {
state.stdout(line.to_string())?;
Ok(())
}
fn on_stderr_line(
state: &JobState<'_, '_>,
line: &str,
package_id: PackageId,
manifest_path: &std::path::Path,
target: &Target,
options: &mut OutputOptions,
) -> CargoResult<()> {
if on_stderr_line_inner(state, line, package_id, manifest_path, target, options)? {
// Check if caching is enabled.
if let Some((path, cell)) = &mut options.cache_cell {
// Cache the output, which will be replayed later when Fresh.
let f = cell.try_borrow_mut_with(|| paths::create(path))?;
debug_assert!(!line.contains('\n'));
f.write_all(line.as_bytes())?;
f.write_all(&[b'\n'])?;
}
}
Ok(())
}
/// Returns true if the line should be cached.
fn on_stderr_line_inner(
state: &JobState<'_, '_>,
line: &str,
package_id: PackageId,
manifest_path: &std::path::Path,
target: &Target,
options: &mut OutputOptions,
) -> CargoResult<bool> {
// We primarily want to use this function to process JSON messages from
// rustc. The compiler should always print one JSON message per line, and
// otherwise it may have other output intermingled (think RUST_LOG or
// something like that), so skip over everything that doesn't look like a
// JSON message.
if !line.starts_with('{') {
state.stderr(line.to_string())?;
return Ok(true);
}
let mut compiler_message: Box<serde_json::value::RawValue> = match serde_json::from_str(line) {
Ok(msg) => msg,
// If the compiler produced a line that started with `{` but it wasn't
// valid JSON, maybe it wasn't JSON in the first place! Forward it along
// to stderr.
Err(e) => {
debug!("failed to parse json: {:?}", e);
state.stderr(line.to_string())?;
return Ok(true);
}
};
let count_diagnostic = |level, options: &mut OutputOptions| {
if level == "warning" {
options.warnings_seen += 1;
} else if level == "error" {
options.errors_seen += 1;
}
};
if let Ok(report) = serde_json::from_str::<FutureIncompatReport>(compiler_message.get()) {
for item in &report.future_incompat_report {
count_diagnostic(&*item.diagnostic.level, options);
}
state.future_incompat_report(report.future_incompat_report);
return Ok(true);
}
// Depending on what we're emitting from Cargo itself, we figure out what to
// do with this JSON message.
match options.format {
// In the "human" output formats (human/short) or if diagnostic messages
// from rustc aren't being included in the output of Cargo's JSON
// messages then we extract the diagnostic (if present) here and handle
// it ourselves.
MessageFormat::Human
| MessageFormat::Short
| MessageFormat::Json {
render_diagnostics: true,
..
} => {
#[derive(serde::Deserialize)]
struct CompilerMessage {
rendered: String,
message: String,
level: String,
children: Vec<PartialDiagnostic>,
}
// A partial rustfix::diagnostics::Diagnostic. We deserialize only a
// subset of the fields because rustc's output can be extremely
// deeply nested JSON in pathological cases involving macro
// expansion. Rustfix's Diagnostic struct is recursive containing a
// field `children: Vec<Self>`, and it can cause deserialization to
// hit serde_json's default recursion limit, or overflow the stack
// if we turn that off. Cargo only cares about the 1 field listed
// here.
#[derive(serde::Deserialize)]
struct PartialDiagnostic {
spans: Vec<PartialDiagnosticSpan>,
}
// A partial rustfix::diagnostics::DiagnosticSpan.
#[derive(serde::Deserialize)]
struct PartialDiagnosticSpan {
suggestion_applicability: Option<Applicability>,
}
if let Ok(mut msg) = serde_json::from_str::<CompilerMessage>(compiler_message.get()) {
if msg.message.starts_with("aborting due to")
|| msg.message.ends_with("warning emitted")
|| msg.message.ends_with("warnings emitted")
{
// Skip this line; we'll print our own summary at the end.
return Ok(true);
}
// state.stderr will add a newline
if msg.rendered.ends_with('\n') {
msg.rendered.pop();
}
let rendered = msg.rendered;
if options.show_diagnostics {
let machine_applicable: bool = msg
.children
.iter()
.map(|child| {
child
.spans
.iter()
.filter_map(|span| span.suggestion_applicability)
.any(|app| app == Applicability::MachineApplicable)
})
.any(|b| b);
count_diagnostic(&msg.level, options);
state.emit_diag(msg.level, rendered, machine_applicable)?;
}
return Ok(true);
}
}
// Remove color information from the rendered string if color is not
// enabled. Cargo always asks for ANSI colors from rustc. This allows
// cached replay to enable/disable colors without re-invoking rustc.
MessageFormat::Json { ansi: false, .. } => {
#[derive(serde::Deserialize, serde::Serialize)]
struct CompilerMessage {
rendered: String,
#[serde(flatten)]
other: std::collections::BTreeMap<String, serde_json::Value>,
}
if let Ok(mut error) = serde_json::from_str::<CompilerMessage>(compiler_message.get()) {
error.rendered = anstream::adapter::strip_str(&error.rendered).to_string();
let new_line = serde_json::to_string(&error)?;
let new_msg: Box<serde_json::value::RawValue> = serde_json::from_str(&new_line)?;
compiler_message = new_msg;
}
}
// If ansi colors are desired then we should be good to go! We can just
// pass through this message as-is.
MessageFormat::Json { ansi: true, .. } => {}
}
// We always tell rustc to emit messages about artifacts being produced.
// These messages feed into pipelined compilation, as well as timing
// information.
//
// Look for a matching directive and inform Cargo internally that a
// metadata file has been produced.
#[derive(serde::Deserialize)]
struct ArtifactNotification {
artifact: String,
}
if let Ok(artifact) = serde_json::from_str::<ArtifactNotification>(compiler_message.get()) {
trace!("found directive from rustc: `{}`", artifact.artifact);
if artifact.artifact.ends_with(".rmeta") {
debug!("looks like metadata finished early!");
state.rmeta_produced();
}
return Ok(false);
}
// And failing all that above we should have a legitimate JSON diagnostic
// from the compiler, so wrap it in an external Cargo JSON message
// indicating which package it came from and then emit it.
if !options.show_diagnostics {
return Ok(true);
}
#[derive(serde::Deserialize)]
struct CompilerMessage {
level: String,
}
if let Ok(message) = serde_json::from_str::<CompilerMessage>(compiler_message.get()) {
count_diagnostic(&message.level, options);
}
let msg = machine_message::FromCompiler {
package_id,
manifest_path,
target,
message: compiler_message,
}
.to_json_string();
// Switch json lines from rustc/rustdoc that appear on stderr to stdout
// instead. We want the stdout of Cargo to always be machine parseable as
// stderr has our colorized human-readable messages.
state.stdout(msg)?;
Ok(true)
}
/// Creates a unit of work that replays the cached compiler message.
///
/// Usually used when a job is fresh and doesn't need to recompile.
fn replay_output_cache(
package_id: PackageId,
manifest_path: PathBuf,
target: &Target,
path: PathBuf,
format: MessageFormat,
show_diagnostics: bool,
) -> Work {
let target = target.clone();
let mut options = OutputOptions {
format,
cache_cell: None,
show_diagnostics,
warnings_seen: 0,
errors_seen: 0,
};
Work::new(move |state| {
if !path.exists() {
// No cached output, probably didn't emit anything.
return Ok(());
}
// We sometimes have gigabytes of output from the compiler, so avoid
// loading it all into memory at once, as that can cause OOM where
// otherwise there would be none.
let file = paths::open(&path)?;
let mut reader = std::io::BufReader::new(file);
let mut line = String::new();
loop {
let length = reader.read_line(&mut line)?;
if length == 0 {
break;
}
let trimmed = line.trim_end_matches(&['\n', '\r'][..]);
on_stderr_line(
state,
trimmed,
package_id,
&manifest_path,
&target,
&mut options,
)?;
line.clear();
}
Ok(())
})
}
/// Provides a package name with descriptive target information,
/// e.g., '`foo` (bin "bar" test)', '`foo` (lib doctest)'.
fn descriptive_pkg_name(name: &str, target: &Target, mode: &CompileMode) -> String {
let desc_name = target.description_named();
let mode = if mode.is_rustc_test() && !(target.is_test() || target.is_bench()) {
" test"
} else if mode.is_doc_test() {
" doctest"
} else if mode.is_doc() {
" doc"
} else {
""
};
format!("`{name}` ({desc_name}{mode})")
}
/// Applies environment variables from config `[env]` to [`ProcessBuilder`].
fn apply_env_config(config: &crate::Config, cmd: &mut ProcessBuilder) -> CargoResult<()> {
for (key, value) in config.env_config()?.iter() {
// never override a value that has already been set by cargo
if cmd.get_envs().contains_key(key) {
continue;
}
if value.is_force() || config.get_env_os(key).is_none() {
cmd.env(key, value.resolve(config));
}
}
Ok(())
}
/// Checks if there are some scrape units waiting to be processed.
fn should_include_scrape_units(bcx: &BuildContext<'_, '_>, unit: &Unit) -> bool {
unit.mode.is_doc() && bcx.scrape_units.len() > 0 && bcx.ws.unit_needs_doc_scrape(unit)
}
/// Gets the file path of function call information output from `rustdoc`.
fn scrape_output_path(cx: &Context<'_, '_>, unit: &Unit) -> CargoResult<PathBuf> {
assert!(unit.mode.is_doc() || unit.mode.is_doc_scrape());
cx.outputs(unit).map(|outputs| outputs[0].path.clone())
}