#
cargo/core/compiler/
mod.rs

    1//! # Interact with the compiler
    2//!
    3//! If you consider [`ops::cargo_compile::compile`] as a `rustc` driver but on
    4//! Cargo side, this module is kinda the `rustc_interface` for that merits.
    5//! It contains all the interaction between Cargo and the rustc compiler,
    6//! from preparing the context for the entire build process, to scheduling
    7//! and executing each unit of work (e.g. running `rustc`), to managing and
    8//! caching the output artifact of a build.
    9//!
    10//! However, it hasn't yet exposed a clear definition of each phase or session,
    11//! like what rustc has done[^1]. Also, no one knows if Cargo really needs that.
    12//! To be pragmatic, here we list a handful of items you may want to learn:
    13//!
    14//! * [`BuildContext`] is a static context containing all information you need
    15//!   before a build gets started.
    16//! * [`BuildRunner`] is the center of the world, coordinating a running build and
    17//!   collecting information from it.
    18//! * [`custom_build`] is the home of build script executions and output parsing.
    19//! * [`fingerprint`] not only defines but also executes a set of rules to
    20//!   determine if a re-compile is needed.
    21//! * [`job_queue`] is where the parallelism, job scheduling, and communication
    22//!   machinery happen between Cargo and the compiler.
    23//! * [`layout`] defines and manages output artifacts of a build in the filesystem.
    24//! * [`unit_dependencies`] is for building a dependency graph for compilation
    25//!   from a result of dependency resolution.
    26//! * [`Unit`] contains sufficient information to build something, usually
    27//!   turning into a compiler invocation in a later phase.
    28//!
    29//! [^1]: Maybe [`-Zbuild-plan`](https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#build-plan)
    30//!   was designed to serve that purpose but still [in flux](https://github.com/rust-lang/cargo/issues/7614).
    31//!
    32//! [`ops::cargo_compile::compile`]: crate::ops::compile
    33
    34pub mod artifact;
    35mod build_config;
    36pub(crate) mod build_context;
    37mod build_plan;
    38pub(crate) mod build_runner;
    39mod compilation;
    40mod compile_kind;
    41mod crate_type;
    42mod custom_build;
    43pub(crate) mod fingerprint;
    44pub mod future_incompat;
    45pub(crate) mod job_queue;
    46pub(crate) mod layout;
    47mod links;
    48mod lto;
    49mod output_depinfo;
    50mod output_sbom;
    51pub mod rustdoc;
    52pub mod standard_lib;
    53mod timings;
    54mod unit;
    55pub mod unit_dependencies;
    56pub mod unit_graph;
    57
    58use std::borrow::Cow;
    59use std::collections::{HashMap, HashSet};
    60use std::env;
    61use std::ffi::{OsStr, OsString};
    62use std::fmt::Display;
    63use std::fs::{self, File};
    64use std::io::{BufRead, BufWriter, Write};
    65use std::path::{Path, PathBuf};
    66use std::sync::Arc;
    67
    68use anyhow::{Context as _, Error};
    69use lazycell::LazyCell;
    70use tracing::{debug, instrument, trace};
    71
    72pub use self::build_config::UserIntent;
    73pub use self::build_config::{BuildConfig, CompileMode, MessageFormat, TimingOutput};
    74pub use self::build_context::{
    75    BuildContext, FileFlavor, FileType, RustDocFingerprint, RustcTargetData, TargetInfo,
    76};
    77use self::build_plan::BuildPlan;
    78pub use self::build_runner::{BuildRunner, Metadata, UnitHash};
    79pub use self::compilation::{Compilation, Doctest, UnitOutput};
    80pub use self::compile_kind::{CompileKind, CompileKindFallback, CompileTarget};
    81pub use self::crate_type::CrateType;
    82pub use self::custom_build::LinkArgTarget;
    83pub use self::custom_build::{BuildOutput, BuildScriptOutputs, BuildScripts, LibraryPath};
    84pub(crate) use self::fingerprint::DirtyReason;
    85pub use self::job_queue::Freshness;
    86use self::job_queue::{Job, JobQueue, JobState, Work};
    87pub(crate) use self::layout::Layout;
    88pub use self::lto::Lto;
    89use self::output_depinfo::output_depinfo;
    90use self::output_sbom::build_sbom;
    91use self::unit_graph::UnitDep;
    92use crate::core::compiler::future_incompat::FutureIncompatReport;
    93pub use crate::core::compiler::unit::{Unit, UnitInterner};
    94use crate::core::manifest::TargetSourcePath;
    95use crate::core::profiles::{PanicStrategy, Profile, StripInner};
    96use crate::core::{Feature, PackageId, Target, Verbosity};
    97use crate::util::context::WarningHandling;
    98use crate::util::errors::{CargoResult, VerboseError};
    99use crate::util::interning::InternedString;
    100use crate::util::machine_message::{self, Message};
    101use crate::util::{add_path_args, internal};
    102use cargo_util::{paths, ProcessBuilder, ProcessError};
    103use cargo_util_schemas::manifest::TomlDebugInfo;
    104use cargo_util_schemas::manifest::TomlTrimPaths;
    105use cargo_util_schemas::manifest::TomlTrimPathsValue;
    106use rustfix::diagnostics::Applicability;
    107
    108const RUSTDOC_CRATE_VERSION_FLAG: &str = "--crate-version";
    109
    110/// A glorified callback for executing calls to rustc. Rather than calling rustc
    111/// directly, we'll use an `Executor`, giving clients an opportunity to intercept
    112/// the build calls.
    113pub trait Executor: Send + Sync + 'static {
    114    /// Called after a rustc process invocation is prepared up-front for a given
    115    /// unit of work (may still be modified for runtime-known dependencies, when
    116    /// the work is actually executed).
    117    fn init(&self, _build_runner: &BuildRunner<'_, '_>, _unit: &Unit) {}
    118
    119    /// In case of an `Err`, Cargo will not continue with the build process for
    120    /// this package.
    121    fn exec(
    122        &self,
    123        cmd: &ProcessBuilder,
    124        id: PackageId,
    125        target: &Target,
    126        mode: CompileMode,
    127        on_stdout_line: &mut dyn FnMut(&str) -> CargoResult<()>,
    128        on_stderr_line: &mut dyn FnMut(&str) -> CargoResult<()>,
    129    ) -> CargoResult<()>;
    130
    131    /// Queried when queuing each unit of work. If it returns true, then the
    132    /// unit will always be rebuilt, independent of whether it needs to be.
    133    fn force_rebuild(&self, _unit: &Unit) -> bool {
    134        false
    135    }
    136}
    137
    138/// A `DefaultExecutor` calls rustc without doing anything else. It is Cargo's
    139/// default behaviour.
    140#[derive(Copy, Clone)]
    141pub struct DefaultExecutor;
    142
    143impl Executor for DefaultExecutor {
    144    #[instrument(name = "rustc", skip_all, fields(package = id.name().as_str(), process = cmd.to_string()))]
    145    fn exec(
    146        &self,
    147        cmd: &ProcessBuilder,
    148        id: PackageId,
    149        _target: &Target,
    150        _mode: CompileMode,
    151        on_stdout_line: &mut dyn FnMut(&str) -> CargoResult<()>,
    152        on_stderr_line: &mut dyn FnMut(&str) -> CargoResult<()>,
    153    ) -> CargoResult<()> {
    154        cmd.exec_with_streaming(on_stdout_line, on_stderr_line, false)
    155            .map(drop)
    156    }
    157}
    158
    159/// Builds up and enqueue a list of pending jobs onto the `job` queue.
    160///
    161/// Starting from the `unit`, this function recursively calls itself to build
    162/// all jobs for dependencies of the `unit`. Each of these jobs represents
    163/// compiling a particular package.
    164///
    165/// Note that **no actual work is executed as part of this**, that's all done
    166/// next as part of [`JobQueue::execute`] function which will run everything
    167/// in order with proper parallelism.
    168#[tracing::instrument(skip(build_runner, jobs, plan, exec))]
    169fn compile<'gctx>(
    170    build_runner: &mut BuildRunner<'_, 'gctx>,
    171    jobs: &mut JobQueue<'gctx>,
    172    plan: &mut BuildPlan,
    173    unit: &Unit,
    174    exec: &Arc<dyn Executor>,
    175    force_rebuild: bool,
    176) -> CargoResult<()> {
    177    let bcx = build_runner.bcx;
    178    let build_plan = bcx.build_config.build_plan;
    179    if !build_runner.compiled.insert(unit.clone()) {
    180        return Ok(());
    181    }
    182
    183    // If we are in `--compile-time-deps` and the given unit is not a compile time
    184    // dependency, skip compling the unit and jumps to dependencies, which still
    185    // have chances to be compile time dependencies
    186    if !unit.skip_non_compile_time_dep {
    187        // Build up the work to be done to compile this unit, enqueuing it once
    188        // we've got everything constructed.
    189        fingerprint::prepare_init(build_runner, unit)?;
    190
    191        let job = if unit.mode.is_run_custom_build() {
    192            custom_build::prepare(build_runner, unit)?
    193        } else if unit.mode.is_doc_test() {
    194            // We run these targets later, so this is just a no-op for now.
    195            Job::new_fresh()
    196        } else if build_plan {
    197            Job::new_dirty(
    198                rustc(build_runner, unit, &exec.clone())?,
    199                DirtyReason::FreshBuild,
    200            )
    201        } else {
    202            let force = exec.force_rebuild(unit) || force_rebuild;
    203            let mut job = fingerprint::prepare_target(build_runner, unit, force)?;
    204            job.before(if job.freshness().is_dirty() {
    205                let work = if unit.mode.is_doc() || unit.mode.is_doc_scrape() {
    206                    rustdoc(build_runner, unit)?
    207                } else {
    208                    rustc(build_runner, unit, exec)?
    209                };
    210                work.then(link_targets(build_runner, unit, false)?)
    211            } else {
    212                // We always replay the output cache,
    213                // since it might contain future-incompat-report messages
    214                let show_diagnostics = unit.show_warnings(bcx.gctx)
    215                    && build_runner.bcx.gctx.warning_handling()? != WarningHandling::Allow;
    216                let work = replay_output_cache(
    217                    unit.pkg.package_id(),
    218                    PathBuf::from(unit.pkg.manifest_path()),
    219                    &unit.target,
    220                    build_runner.files().message_cache_path(unit),
    221                    build_runner.bcx.build_config.message_format,
    222                    show_diagnostics,
    223                );
    224                // Need to link targets on both the dirty and fresh.
    225                work.then(link_targets(build_runner, unit, true)?)
    226            });
    227
    228            job
    229        };
    230        jobs.enqueue(build_runner, unit, job)?;
    231    }
    232
    233    // Be sure to compile all dependencies of this target as well.
    234    let deps = Vec::from(build_runner.unit_deps(unit)); // Create vec due to mutable borrow.
    235    for dep in deps {
    236        compile(build_runner, jobs, plan, &dep.unit, exec, false)?;
    237    }
    238    if build_plan {
    239        plan.add(build_runner, unit)?;
    240    }
    241
    242    Ok(())
    243}
    244
    245/// Generates the warning message used when fallible doc-scrape units fail,
    246/// either for rustdoc or rustc.
    247fn make_failed_scrape_diagnostic(
    248    build_runner: &BuildRunner<'_, '_>,
    249    unit: &Unit,
    250    top_line: impl Display,
    251) -> String {
    252    let manifest_path = unit.pkg.manifest_path();
    253    let relative_manifest_path = manifest_path
    254        .strip_prefix(build_runner.bcx.ws.root())
    255        .unwrap_or(&manifest_path);
    256
    257    format!(
    258        "\
    259{top_line}
    260    Try running with `--verbose` to see the error message.
    261    If an example should not be scanned, then consider adding `doc-scrape-examples = false` to its `[[example]]` definition in {}",
    262        relative_manifest_path.display()
    263    )
    264}
    265
    266/// Creates a unit of work invoking `rustc` for building the `unit`.
    267fn rustc(
    268    build_runner: &mut BuildRunner<'_, '_>,
    269    unit: &Unit,
    270    exec: &Arc<dyn Executor>,
    271) -> CargoResult<Work> {
    272    let mut rustc = prepare_rustc(build_runner, unit)?;
    273    let build_plan = build_runner.bcx.build_config.build_plan;
    274
    275    let name = unit.pkg.name();
    276    let buildkey = unit.buildkey();
    277
    278    let outputs = build_runner.outputs(unit)?;
    279    let root = build_runner.files().out_dir(unit);
    280
    281    // Prepare the native lib state (extra `-L` and `-l` flags).
    282    let build_script_outputs = Arc::clone(&build_runner.build_script_outputs);
    283    let current_id = unit.pkg.package_id();
    284    let manifest_path = PathBuf::from(unit.pkg.manifest_path());
    285    let build_scripts = build_runner.build_scripts.get(unit).cloned();
    286
    287    // If we are a binary and the package also contains a library, then we
    288    // don't pass the `-l` flags.
    289    let pass_l_flag = unit.target.is_lib() || !unit.pkg.targets().iter().any(|t| t.is_lib());
    290
    291    let dep_info_name =
    292        if let Some(c_extra_filename) = build_runner.files().metadata(unit).c_extra_filename() {
    293            format!("{}-{}.d", unit.target.crate_name(), c_extra_filename)
    294        } else {
    295            format!("{}.d", unit.target.crate_name())
    296        };
    297    let rustc_dep_info_loc = root.join(dep_info_name);
    298    let dep_info_loc = fingerprint::dep_info_loc(build_runner, unit);
    299
    300    let mut output_options = OutputOptions::new(build_runner, unit);
    301    let package_id = unit.pkg.package_id();
    302    let target = Target::clone(&unit.target);
    303    let mode = unit.mode;
    304
    305    exec.init(build_runner, unit);
    306    let exec = exec.clone();
    307
    308    let root_output = build_runner.files().host_dest().to_path_buf();
    309    let build_dir = build_runner.bcx.ws.build_dir().into_path_unlocked();
    310    let pkg_root = unit.pkg.root().to_path_buf();
    311    let cwd = rustc
    312        .get_cwd()
    313        .unwrap_or_else(|| build_runner.bcx.gctx.cwd())
    314        .to_path_buf();
    315    let fingerprint_dir = build_runner.files().fingerprint_dir(unit);
    316    let script_metadata = build_runner.find_build_script_metadata(unit);
    317    let is_local = unit.is_local();
    318    let artifact = unit.artifact;
    319    let sbom_files = build_runner.sbom_output_files(unit)?;
    320    let sbom = build_sbom(build_runner, unit)?;
    321
    322    let hide_diagnostics_for_scrape_unit = build_runner.bcx.unit_can_fail_for_docscraping(unit)
    323        && !matches!(
    324            build_runner.bcx.gctx.shell().verbosity(),
    325            Verbosity::Verbose
    326        );
    327    let failed_scrape_diagnostic = hide_diagnostics_for_scrape_unit.then(|| {
    328        // If this unit is needed for doc-scraping, then we generate a diagnostic that
    329        // describes the set of reverse-dependencies that cause the unit to be needed.
    330        let target_desc = unit.target.description_named();
    331        let mut for_scrape_units = build_runner
    332            .bcx
    333            .scrape_units_have_dep_on(unit)
    334            .into_iter()
    335            .map(|unit| unit.target.description_named())
    336            .collect::<Vec<_>>();
    337        for_scrape_units.sort();
    338        let for_scrape_units = for_scrape_units.join(", ");
    339        make_failed_scrape_diagnostic(build_runner, unit, format_args!("failed to check {target_desc} in package `{name}` as a prerequisite for scraping examples from: {for_scrape_units}"))
    340    });
    341    if hide_diagnostics_for_scrape_unit {
    342        output_options.show_diagnostics = false;
    343    }
    344    let env_config = Arc::clone(build_runner.bcx.gctx.env_config()?);
    345    return Ok(Work::new(move |state| {
    346        // Artifacts are in a different location than typical units,
    347        // hence we must assure the crate- and target-dependent
    348        // directory is present.
    349        if artifact.is_true() {
    350            paths::create_dir_all(&root)?;
    351        }
    352
    353        // Only at runtime have we discovered what the extra -L and -l
    354        // arguments are for native libraries, so we process those here. We
    355        // also need to be sure to add any -L paths for our plugins to the
    356        // dynamic library load path as a plugin's dynamic library may be
    357        // located somewhere in there.
    358        // Finally, if custom environment variables have been produced by
    359        // previous build scripts, we include them in the rustc invocation.
    360        if let Some(build_scripts) = build_scripts {
    361            let script_outputs = build_script_outputs.lock().unwrap();
    362            if !build_plan {
    363                add_native_deps(
    364                    &mut rustc,
    365                    &script_outputs,
    366                    &build_scripts,
    367                    pass_l_flag,
    368                    &target,
    369                    current_id,
    370                    mode,
    371                )?;
    372                add_plugin_deps(&mut rustc, &script_outputs, &build_scripts, &root_output)?;
    373            }
    374            add_custom_flags(&mut rustc, &script_outputs, script_metadata)?;
    375        }
    376
    377        for output in outputs.iter() {
    378            // If there is both an rmeta and rlib, rustc will prefer to use the
    379            // rlib, even if it is older. Therefore, we must delete the rlib to
    380            // force using the new rmeta.
    381            if output.path.extension() == Some(OsStr::new("rmeta")) {
    382                let dst = root.join(&output.path).with_extension("rlib");
    383                if dst.exists() {
    384                    paths::remove_file(&dst)?;
    385                }
    386            }
    387
    388            // Some linkers do not remove the executable, but truncate and modify it.
    389            // That results in the old hard-link being modified even after renamed.
    390            // We delete the old artifact here to prevent this behavior from confusing users.
    391            // See rust-lang/cargo#8348.
    392            if output.hardlink.is_some() && output.path.exists() {
    393                _ = paths::remove_file(&output.path).map_err(|e| {
    394                    tracing::debug!(
    395                        "failed to delete previous output file `{:?}`: {e:?}",
    396                        output.path
    397                    );
    398                });
    399            }
    400        }
    401
    402        state.running(&rustc);
    403        let timestamp = paths::set_invocation_time(&fingerprint_dir)?;
    404        if build_plan {
    405            state.build_plan(buildkey, rustc.clone(), outputs.clone());
    406        } else {
    407            for file in sbom_files {
    408                tracing::debug!("writing sbom to {}", file.display());
    409                let outfile = BufWriter::new(paths::create(&file)?);
    410                serde_json::to_writer(outfile, &sbom)?;
    411            }
    412
    413            let result = exec
    414                .exec(
    415                    &rustc,
    416                    package_id,
    417                    &target,
    418                    mode,
    419                    &mut |line| on_stdout_line(state, line, package_id, &target),
    420                    &mut |line| {
    421                        on_stderr_line(
    422                            state,
    423                            line,
    424                            package_id,
    425                            &manifest_path,
    426                            &target,
    427                            &mut output_options,
    428                        )
    429                    },
    430                )
    431                .map_err(|e| {
    432                    if output_options.errors_seen == 0 {
    433                        // If we didn't expect an error, do not require --verbose to fail.
    434                        // This is intended to debug
    435                        // https://github.com/rust-lang/crater/issues/733, where we are seeing
    436                        // Cargo exit unsuccessfully while seeming to not show any errors.
    437                        e
    438                    } else {
    439                        verbose_if_simple_exit_code(e)
    440                    }
    441                })
    442                .with_context(|| {
    443                    // adapted from rustc_errors/src/lib.rs
    444                    let warnings = match output_options.warnings_seen {
    445                        0 => String::new(),
    446                        1 => "; 1 warning emitted".to_string(),
    447                        count => format!("; {} warnings emitted", count),
    448                    };
    449                    let errors = match output_options.errors_seen {
    450                        0 => String::new(),
    451                        1 => " due to 1 previous error".to_string(),
    452                        count => format!(" due to {} previous errors", count),
    453                    };
    454                    let name = descriptive_pkg_name(&name, &target, &mode);
    455                    format!("could not compile {name}{errors}{warnings}")
    456                });
    457
    458            if let Err(e) = result {
    459                if let Some(diagnostic) = failed_scrape_diagnostic {
    460                    state.warning(diagnostic);
    461                }
    462
    463                return Err(e);
    464            }
    465
    466            // Exec should never return with success *and* generate an error.
    467            debug_assert_eq!(output_options.errors_seen, 0);
    468        }
    469
    470        if rustc_dep_info_loc.exists() {
    471            fingerprint::translate_dep_info(
    472                &rustc_dep_info_loc,
    473                &dep_info_loc,
    474                &cwd,
    475                &pkg_root,
    476                &build_dir,
    477                &rustc,
    478                // Do not track source files in the fingerprint for registry dependencies.
    479                is_local,
    480                &env_config,
    481            )
    482            .with_context(|| {
    483                internal(format!(
    484                    "could not parse/generate dep info at: {}",
    485                    rustc_dep_info_loc.display()
    486                ))
    487            })?;
    488            // This mtime shift allows Cargo to detect if a source file was
    489            // modified in the middle of the build.
    490            paths::set_file_time_no_err(dep_info_loc, timestamp);
    491        }
    492
    493        Ok(())
    494    }));
    495
    496    // Add all relevant `-L` and `-l` flags from dependencies (now calculated and
    497    // present in `state`) to the command provided.
    498    fn add_native_deps(
    499        rustc: &mut ProcessBuilder,
    500        build_script_outputs: &BuildScriptOutputs,
    501        build_scripts: &BuildScripts,
    502        pass_l_flag: bool,
    503        target: &Target,
    504        current_id: PackageId,
    505        mode: CompileMode,
    506    ) -> CargoResult<()> {
    507        let mut library_paths = vec![];
    508
    509        for key in build_scripts.to_link.iter() {
    510            let output = build_script_outputs.get(key.1).ok_or_else(|| {
    511                internal(format!(
    512                    "couldn't find build script output for {}/{}",
    513                    key.0, key.1
    514                ))
    515            })?;
    516            library_paths.extend(output.library_paths.iter());
    517        }
    518
    519        // NOTE: This very intentionally does not use the derived ord from LibraryPath because we need to
    520        // retain relative ordering within the same type (i.e. not lexicographic). The use of a stable sort
    521        // is also important here because it ensures that paths of the same type retain the same relative
    522        // ordering (for an unstable sort to work here, the list would need to retain the idx of each element
    523        // and then sort by that idx when the type is equivalent.
    524        library_paths.sort_by_key(|p| match p {
    525            LibraryPath::CargoArtifact(_) => 0,
    526            LibraryPath::External(_) => 1,
    527        });
    528
    529        for path in library_paths.iter() {
    530            rustc.arg("-L").arg(path.as_ref());
    531        }
    532
    533        for key in build_scripts.to_link.iter() {
    534            let output = build_script_outputs.get(key.1).ok_or_else(|| {
    535                internal(format!(
    536                    "couldn't find build script output for {}/{}",
    537                    key.0, key.1
    538                ))
    539            })?;
    540
    541            if key.0 == current_id {
    542                if pass_l_flag {
    543                    for name in output.library_links.iter() {
    544                        rustc.arg("-l").arg(name);
    545                    }
    546                }
    547            }
    548
    549            for (lt, arg) in &output.linker_args {
    550                // There was an unintentional change where cdylibs were
    551                // allowed to be passed via transitive dependencies. This
    552                // clause should have been kept in the `if` block above. For
    553                // now, continue allowing it for cdylib only.
    554                // See https://github.com/rust-lang/cargo/issues/9562
    555                if lt.applies_to(target, mode)
    556                    && (key.0 == current_id || *lt == LinkArgTarget::Cdylib)
    557                {
    558                    rustc.arg("-C").arg(format!("link-arg={}", arg));
    559                }
    560            }
    561        }
    562        Ok(())
    563    }
    564}
    565
    566fn verbose_if_simple_exit_code(err: Error) -> Error {
    567    // If a signal on unix (`code == None`) or an abnormal termination
    568    // on Windows (codes like `0xC0000409`), don't hide the error details.
    569    match err
    570        .downcast_ref::<ProcessError>()
    571        .as_ref()
    572        .and_then(|perr| perr.code)
    573    {
    574        Some(n) if cargo_util::is_simple_exit_code(n) => VerboseError::new(err).into(),
    575        _ => err,
    576    }
    577}
    578
    579/// Link the compiled target (often of form `foo-{metadata_hash}`) to the
    580/// final target. This must happen during both "Fresh" and "Compile".
    581fn link_targets(
    582    build_runner: &mut BuildRunner<'_, '_>,
    583    unit: &Unit,
    584    fresh: bool,
    585) -> CargoResult<Work> {
    586    let bcx = build_runner.bcx;
    587    let outputs = build_runner.outputs(unit)?;
    588    let export_dir = build_runner.files().export_dir();
    589    let package_id = unit.pkg.package_id();
    590    let manifest_path = PathBuf::from(unit.pkg.manifest_path());
    591    let profile = unit.profile.clone();
    592    let unit_mode = unit.mode;
    593    let features = unit.features.iter().map(|s| s.to_string()).collect();
    594    let json_messages = bcx.build_config.emit_json();
    595    let executable = build_runner.get_executable(unit)?;
    596    let mut target = Target::clone(&unit.target);
    597    if let TargetSourcePath::Metabuild = target.src_path() {
    598        // Give it something to serialize.
    599        let path = unit
    600            .pkg
    601            .manifest()
    602            .metabuild_path(build_runner.bcx.ws.build_dir());
    603        target.set_src_path(TargetSourcePath::Path(path));
    604    }
    605
    606    Ok(Work::new(move |state| {
    607        // If we're a "root crate", e.g., the target of this compilation, then we
    608        // hard link our outputs out of the `deps` directory into the directory
    609        // above. This means that `cargo build` will produce binaries in
    610        // `target/debug` which one probably expects.
    611        let mut destinations = vec![];
    612        for output in outputs.iter() {
    613            let src = &output.path;
    614            // This may have been a `cargo rustc` command which changes the
    615            // output, so the source may not actually exist.
    616            if !src.exists() {
    617                continue;
    618            }
    619            let Some(dst) = output.hardlink.as_ref() else {
    620                destinations.push(src.clone());
    621                continue;
    622            };
    623            destinations.push(dst.clone());
    624            paths::link_or_copy(src, dst)?;
    625            if let Some(ref path) = output.export_path {
    626                let export_dir = export_dir.as_ref().unwrap();
    627                paths::create_dir_all(export_dir)?;
    628
    629                paths::link_or_copy(src, path)?;
    630            }
    631        }
    632
    633        if json_messages {
    634            let debuginfo = match profile.debuginfo.into_inner() {
    635                TomlDebugInfo::None => machine_message::ArtifactDebuginfo::Int(0),
    636                TomlDebugInfo::Limited => machine_message::ArtifactDebuginfo::Int(1),
    637                TomlDebugInfo::Full => machine_message::ArtifactDebuginfo::Int(2),
    638                TomlDebugInfo::LineDirectivesOnly => {
    639                    machine_message::ArtifactDebuginfo::Named("line-directives-only")
    640                }
    641                TomlDebugInfo::LineTablesOnly => {
    642                    machine_message::ArtifactDebuginfo::Named("line-tables-only")
    643                }
    644            };
    645            let art_profile = machine_message::ArtifactProfile {
    646                opt_level: profile.opt_level.as_str(),
    647                debuginfo: Some(debuginfo),
    648                debug_assertions: profile.debug_assertions,
    649                overflow_checks: profile.overflow_checks,
    650                test: unit_mode.is_any_test(),
    651            };
    652
    653            let msg = machine_message::Artifact {
    654                package_id: package_id.to_spec(),
    655                manifest_path,
    656                target: &target,
    657                profile: art_profile,
    658                features,
    659                filenames: destinations,
    660                executable,
    661                fresh,
    662            }
    663            .to_json_string();
    664            state.stdout(msg)?;
    665        }
    666        Ok(())
    667    }))
    668}
    669
    670// For all plugin dependencies, add their -L paths (now calculated and present
    671// in `build_script_outputs`) to the dynamic library load path for the command
    672// to execute.
    673fn add_plugin_deps(
    674    rustc: &mut ProcessBuilder,
    675    build_script_outputs: &BuildScriptOutputs,
    676    build_scripts: &BuildScripts,
    677    root_output: &Path,
    678) -> CargoResult<()> {
    679    let var = paths::dylib_path_envvar();
    680    let search_path = rustc.get_env(var).unwrap_or_default();
    681    let mut search_path = env::split_paths(&search_path).collect::<Vec<_>>();
    682    for (pkg_id, metadata) in &build_scripts.plugins {
    683        let output = build_script_outputs
    684            .get(*metadata)
    685            .ok_or_else(|| internal(format!("couldn't find libs for plugin dep {}", pkg_id)))?;
    686        search_path.append(&mut filter_dynamic_search_path(
    687            output.library_paths.iter().map(AsRef::as_ref),
    688            root_output,
    689        ));
    690    }
    691    let search_path = paths::join_paths(&search_path, var)?;
    692    rustc.env(var, &search_path);
    693    Ok(())
    694}
    695
    696fn get_dynamic_search_path(path: &Path) -> &Path {
    697    match path.to_str().and_then(|s| s.split_once("=")) {
    698        Some(("native" | "crate" | "dependency" | "framework" | "all", path)) => Path::new(path),
    699        _ => path,
    700    }
    701}
    702
    703// Determine paths to add to the dynamic search path from -L entries
    704//
    705// Strip off prefixes like "native=" or "framework=" and filter out directories
    706// **not** inside our output directory since they are likely spurious and can cause
    707// clashes with system shared libraries (issue #3366).
    708fn filter_dynamic_search_path<'a, I>(paths: I, root_output: &Path) -> Vec<PathBuf>
    709where
    710    I: Iterator<Item = &'a PathBuf>,
    711{
    712    let mut search_path = vec![];
    713    for dir in paths {
    714        let dir = get_dynamic_search_path(dir);
    715        if dir.starts_with(&root_output) {
    716            search_path.push(dir.to_path_buf());
    717        } else {
    718            debug!(
    719                "Not including path {} in runtime library search path because it is \
    720                 outside target root {}",
    721                dir.display(),
    722                root_output.display()
    723            );
    724        }
    725    }
    726    search_path
    727}
    728
    729/// Prepares flags and environments we can compute for a `rustc` invocation
    730/// before the job queue starts compiling any unit.
    731///
    732/// This builds a static view of the invocation. Flags depending on the
    733/// completion of other units will be added later in runtime, such as flags
    734/// from build scripts.
    735fn prepare_rustc(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> CargoResult<ProcessBuilder> {
    736    let gctx = build_runner.bcx.gctx;
    737    let is_primary = build_runner.is_primary_package(unit);
    738    let is_workspace = build_runner.bcx.ws.is_member(&unit.pkg);
    739
    740    let mut base = build_runner
    741        .compilation
    742        .rustc_process(unit, is_primary, is_workspace)?;
    743    build_base_args(build_runner, &mut base, unit)?;
    744    if unit.pkg.manifest().is_embedded() {
    745        if !gctx.cli_unstable().script {
    746            anyhow::bail!(
    747                "parsing `{}` requires `-Zscript`",
    748                unit.pkg.manifest_path().display()
    749            );
    750        }
    751        base.arg("-Z").arg("crate-attr=feature(frontmatter)");
    752    }
    753
    754    base.inherit_jobserver(&build_runner.jobserver);
    755    build_deps_args(&mut base, build_runner, unit)?;
    756    add_cap_lints(build_runner.bcx, unit, &mut base);
    757    if let Some(args) = build_runner.bcx.extra_args_for(unit) {
    758        base.args(args);
    759    }
    760    base.args(&unit.rustflags);
    761    if gctx.cli_unstable().binary_dep_depinfo {
    762        base.arg("-Z").arg("binary-dep-depinfo");
    763    }
    764    if build_runner.bcx.gctx.cli_unstable().checksum_freshness {
    765        base.arg("-Z").arg("checksum-hash-algorithm=blake3");
    766    }
    767
    768    if is_primary {
    769        base.env("CARGO_PRIMARY_PACKAGE", "1");
    770        let file_list = std::env::join_paths(build_runner.sbom_output_files(unit)?)?;
    771        base.env("CARGO_SBOM_PATH", file_list);
    772    }
    773
    774    if unit.target.is_test() || unit.target.is_bench() {
    775        let tmp = build_runner.files().layout(unit.kind).prepare_tmp()?;
    776        base.env("CARGO_TARGET_TMPDIR", tmp.display().to_string());
    777    }
    778
    779    Ok(base)
    780}
    781
    782/// Prepares flags and environments we can compute for a `rustdoc` invocation
    783/// before the job queue starts compiling any unit.
    784///
    785/// This builds a static view of the invocation. Flags depending on the
    786/// completion of other units will be added later in runtime, such as flags
    787/// from build scripts.
    788fn prepare_rustdoc(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> CargoResult<ProcessBuilder> {
    789    let bcx = build_runner.bcx;
    790    // script_metadata is not needed here, it is only for tests.
    791    let mut rustdoc = build_runner.compilation.rustdoc_process(unit, None)?;
    792    if unit.pkg.manifest().is_embedded() {
    793        if !bcx.gctx.cli_unstable().script {
    794            anyhow::bail!(
    795                "parsing `{}` requires `-Zscript`",
    796                unit.pkg.manifest_path().display()
    797            );
    798        }
    799        rustdoc.arg("-Z").arg("crate-attr=feature(frontmatter)");
    800    }
    801    rustdoc.inherit_jobserver(&build_runner.jobserver);
    802    let crate_name = unit.target.crate_name();
    803    rustdoc.arg("--crate-name").arg(&crate_name);
    804    add_path_args(bcx.ws, unit, &mut rustdoc);
    805    add_cap_lints(bcx, unit, &mut rustdoc);
    806
    807    if let CompileKind::Target(target) = unit.kind {
    808        rustdoc.arg("--target").arg(target.rustc_target());
    809    }
    810    let doc_dir = build_runner.files().out_dir(unit);
    811    rustdoc.arg("-o").arg(&doc_dir);
    812    rustdoc.args(&features_args(unit));
    813    rustdoc.args(&check_cfg_args(unit));
    814
    815    add_error_format_and_color(build_runner, &mut rustdoc);
    816    add_allow_features(build_runner, &mut rustdoc);
    817
    818    if build_runner.bcx.gctx.cli_unstable().rustdoc_depinfo {
    819        // toolchain-shared-resources is required for keeping the shared styling resources
    820        // invocation-specific is required for keeping the original rustdoc emission
    821        let mut arg =
    822            OsString::from("--emit=toolchain-shared-resources,invocation-specific,dep-info=");
    823        arg.push(rustdoc_dep_info_loc(build_runner, unit));
    824        rustdoc.arg(arg);
    825
    826        if build_runner.bcx.gctx.cli_unstable().checksum_freshness {
    827            rustdoc.arg("-Z").arg("checksum-hash-algorithm=blake3");
    828        }
    829
    830        rustdoc.arg("-Zunstable-options");
    831    }
    832
    833    if let Some(trim_paths) = unit.profile.trim_paths.as_ref() {
    834        trim_paths_args_rustdoc(&mut rustdoc, build_runner, unit, trim_paths)?;
    835    }
    836
    837    rustdoc.args(unit.pkg.manifest().lint_rustflags());
    838
    839    let metadata = build_runner.metadata_for_doc_units[unit];
    840    rustdoc
    841        .arg("-C")
    842        .arg(format!("metadata={}", metadata.c_metadata()));
    843
    844    if unit.mode.is_doc_scrape() {
    845        debug_assert!(build_runner.bcx.scrape_units.contains(unit));
    846
    847        if unit.target.is_test() {
    848            rustdoc.arg("--scrape-tests");
    849        }
    850
    851        rustdoc.arg("-Zunstable-options");
    852
    853        rustdoc
    854            .arg("--scrape-examples-output-path")
    855            .arg(scrape_output_path(build_runner, unit)?);
    856
    857        // Only scrape example for items from crates in the workspace, to reduce generated file size
    858        for pkg in build_runner.bcx.packages.packages() {
    859            let names = pkg
    860                .targets()
    861                .iter()
    862                .map(|target| target.crate_name())
    863                .collect::<HashSet<_>>();
    864            for name in names {
    865                rustdoc.arg("--scrape-examples-target-crate").arg(name);
    866            }
    867        }
    868    }
    869
    870    if should_include_scrape_units(build_runner.bcx, unit) {
    871        rustdoc.arg("-Zunstable-options");
    872    }
    873
    874    build_deps_args(&mut rustdoc, build_runner, unit)?;
    875    rustdoc::add_root_urls(build_runner, unit, &mut rustdoc)?;
    876
    877    rustdoc::add_output_format(build_runner, &mut rustdoc)?;
    878
    879    if let Some(args) = build_runner.bcx.extra_args_for(unit) {
    880        rustdoc.args(args);
    881    }
    882    rustdoc.args(&unit.rustdocflags);
    883
    884    if !crate_version_flag_already_present(&rustdoc) {
    885        append_crate_version_flag(unit, &mut rustdoc);
    886    }
    887
    888    Ok(rustdoc)
    889}
    890
    891/// Creates a unit of work invoking `rustdoc` for documenting the `unit`.
    892fn rustdoc(build_runner: &mut BuildRunner<'_, '_>, unit: &Unit) -> CargoResult<Work> {
    893    let mut rustdoc = prepare_rustdoc(build_runner, unit)?;
    894
    895    let crate_name = unit.target.crate_name();
    896    let doc_dir = build_runner.files().out_dir(unit);
    897    // Create the documentation directory ahead of time as rustdoc currently has
    898    // a bug where concurrent invocations will race to create this directory if
    899    // it doesn't already exist.
    900    paths::create_dir_all(&doc_dir)?;
    901
    902    let target_desc = unit.target.description_named();
    903    let name = unit.pkg.name();
    904    let build_script_outputs = Arc::clone(&build_runner.build_script_outputs);
    905    let package_id = unit.pkg.package_id();
    906    let manifest_path = PathBuf::from(unit.pkg.manifest_path());
    907    let target = Target::clone(&unit.target);
    908
    909    let rustdoc_dep_info_loc = rustdoc_dep_info_loc(build_runner, unit);
    910    let dep_info_loc = fingerprint::dep_info_loc(build_runner, unit);
    911    let build_dir = build_runner.bcx.ws.build_dir().into_path_unlocked();
    912    let pkg_root = unit.pkg.root().to_path_buf();
    913    let cwd = rustdoc
    914        .get_cwd()
    915        .unwrap_or_else(|| build_runner.bcx.gctx.cwd())
    916        .to_path_buf();
    917    let fingerprint_dir = build_runner.files().fingerprint_dir(unit);
    918    let is_local = unit.is_local();
    919    let env_config = Arc::clone(build_runner.bcx.gctx.env_config()?);
    920    let rustdoc_depinfo_enabled = build_runner.bcx.gctx.cli_unstable().rustdoc_depinfo;
    921
    922    let mut output_options = OutputOptions::new(build_runner, unit);
    923    let script_metadata = build_runner.find_build_script_metadata(unit);
    924    let scrape_outputs = if should_include_scrape_units(build_runner.bcx, unit) {
    925        Some(
    926            build_runner
    927                .bcx
    928                .scrape_units
    929                .iter()
    930                .map(|unit| {
    931                    Ok((
    932                        build_runner.files().metadata(unit).unit_id(),
    933                        scrape_output_path(build_runner, unit)?,
    934                    ))
    935                })
    936                .collect::<CargoResult<HashMap<_, _>>>()?,
    937        )
    938    } else {
    939        None
    940    };
    941
    942    let failed_scrape_units = Arc::clone(&build_runner.failed_scrape_units);
    943    let hide_diagnostics_for_scrape_unit = build_runner.bcx.unit_can_fail_for_docscraping(unit)
    944        && !matches!(
    945            build_runner.bcx.gctx.shell().verbosity(),
    946            Verbosity::Verbose
    947        );
    948    let failed_scrape_diagnostic = hide_diagnostics_for_scrape_unit.then(|| {
    949        make_failed_scrape_diagnostic(
    950            build_runner,
    951            unit,
    952            format_args!("failed to scan {target_desc} in package `{name}` for example code usage"),
    953        )
    954    });
    955    if hide_diagnostics_for_scrape_unit {
    956        output_options.show_diagnostics = false;
    957    }
    958
    959    Ok(Work::new(move |state| {
    960        add_custom_flags(
    961            &mut rustdoc,
    962            &build_script_outputs.lock().unwrap(),
    963            script_metadata,
    964        )?;
    965
    966        // Add the output of scraped examples to the rustdoc command.
    967        // This action must happen after the unit's dependencies have finished,
    968        // because some of those deps may be Docscrape units which have failed.
    969        // So we dynamically determine which `--with-examples` flags to pass here.
    970        if let Some(scrape_outputs) = scrape_outputs {
    971            let failed_scrape_units = failed_scrape_units.lock().unwrap();
    972            for (metadata, output_path) in &scrape_outputs {
    973                if !failed_scrape_units.contains(metadata) {
    974                    rustdoc.arg("--with-examples").arg(output_path);
    975                }
    976            }
    977        }
    978
    979        let crate_dir = doc_dir.join(&crate_name);
    980        if crate_dir.exists() {
    981            // Remove output from a previous build. This ensures that stale
    982            // files for removed items are removed.
    983            debug!("removing pre-existing doc directory {:?}", crate_dir);
    984            paths::remove_dir_all(crate_dir)?;
    985        }
    986        state.running(&rustdoc);
    987        let timestamp = paths::set_invocation_time(&fingerprint_dir)?;
    988
    989        let result = rustdoc
    990            .exec_with_streaming(
    991                &mut |line| on_stdout_line(state, line, package_id, &target),
    992                &mut |line| {
    993                    on_stderr_line(
    994                        state,
    995                        line,
    996                        package_id,
    997                        &manifest_path,
    998                        &target,
    999                        &mut output_options,
    1000                    )
    1001                },
    1002                false,
    1003            )
    1004            .map_err(verbose_if_simple_exit_code)
    1005            .with_context(|| format!("could not document `{}`", name));
    1006
    1007        if let Err(e) = result {
    1008            if let Some(diagnostic) = failed_scrape_diagnostic {
    1009                state.warning(diagnostic);
    1010            }
    1011
    1012            return Err(e);
    1013        }
    1014
    1015        if rustdoc_depinfo_enabled && rustdoc_dep_info_loc.exists() {
    1016            fingerprint::translate_dep_info(
    1017                &rustdoc_dep_info_loc,
    1018                &dep_info_loc,
    1019                &cwd,
    1020                &pkg_root,
    1021                &build_dir,
    1022                &rustdoc,
    1023                // Should we track source file for doc gen?
    1024                is_local,
    1025                &env_config,
    1026            )
    1027            .with_context(|| {
    1028                internal(format_args!(
    1029                    "could not parse/generate dep info at: {}",
    1030                    rustdoc_dep_info_loc.display()
    1031                ))
    1032            })?;
    1033            // This mtime shift allows Cargo to detect if a source file was
    1034            // modified in the middle of the build.
    1035            paths::set_file_time_no_err(dep_info_loc, timestamp);
    1036        }
    1037
    1038        Ok(())
    1039    }))
    1040}
    1041
    1042// The --crate-version flag could have already been passed in RUSTDOCFLAGS
    1043// or as an extra compiler argument for rustdoc
    1044fn crate_version_flag_already_present(rustdoc: &ProcessBuilder) -> bool {
    1045    rustdoc.get_args().any(|flag| {
    1046        flag.to_str()
    1047            .map_or(false, |flag| flag.starts_with(RUSTDOC_CRATE_VERSION_FLAG))
    1048    })
    1049}
    1050
    1051fn append_crate_version_flag(unit: &Unit, rustdoc: &mut ProcessBuilder) {
    1052    rustdoc
    1053        .arg(RUSTDOC_CRATE_VERSION_FLAG)
    1054        .arg(unit.pkg.version().to_string());
    1055}
    1056
    1057/// Adds [`--cap-lints`] to the command to execute.
    1058///
    1059/// [`--cap-lints`]: https://doc.rust-lang.org/nightly/rustc/lints/levels.html#capping-lints
    1060fn add_cap_lints(bcx: &BuildContext<'_, '_>, unit: &Unit, cmd: &mut ProcessBuilder) {
    1061    // If this is an upstream dep we don't want warnings from, turn off all
    1062    // lints.
    1063    if !unit.show_warnings(bcx.gctx) {
    1064        cmd.arg("--cap-lints").arg("allow");
    1065
    1066    // If this is an upstream dep but we *do* want warnings, make sure that they
    1067    // don't fail compilation.
    1068    } else if !unit.is_local() {
    1069        cmd.arg("--cap-lints").arg("warn");
    1070    }
    1071}
    1072
    1073/// Forwards [`-Zallow-features`] if it is set for cargo.
    1074///
    1075/// [`-Zallow-features`]: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#allow-features
    1076fn add_allow_features(build_runner: &BuildRunner<'_, '_>, cmd: &mut ProcessBuilder) {
    1077    if let Some(allow) = &build_runner.bcx.gctx.cli_unstable().allow_features {
    1078        use std::fmt::Write;
    1079        let mut arg = String::from("-Zallow-features=");
    1080        for f in allow {
    1081            let _ = write!(&mut arg, "{f},");
    1082        }
    1083        cmd.arg(arg.trim_end_matches(','));
    1084    }
    1085}
    1086
    1087/// Adds [`--error-format`] to the command to execute.
    1088///
    1089/// Cargo always uses JSON output. This has several benefits, such as being
    1090/// easier to parse, handles changing formats (for replaying cached messages),
    1091/// ensures atomic output (so messages aren't interleaved), allows for
    1092/// intercepting messages like rmeta artifacts, etc. rustc includes a
    1093/// "rendered" field in the JSON message with the message properly formatted,
    1094/// which Cargo will extract and display to the user.
    1095///
    1096/// [`--error-format`]: https://doc.rust-lang.org/nightly/rustc/command-line-arguments.html#--error-format-control-how-errors-are-produced
    1097fn add_error_format_and_color(build_runner: &BuildRunner<'_, '_>, cmd: &mut ProcessBuilder) {
    1098    cmd.arg("--error-format=json");
    1099    let mut json = String::from("--json=diagnostic-rendered-ansi,artifacts,future-incompat");
    1100
    1101    match build_runner.bcx.build_config.message_format {
    1102        MessageFormat::Short | MessageFormat::Json { short: true, .. } => {
    1103            json.push_str(",diagnostic-short");
    1104        }
    1105        _ => {}
    1106    }
    1107    cmd.arg(json);
    1108
    1109    let gctx = build_runner.bcx.gctx;
    1110    if let Some(width) = gctx.shell().err_width().diagnostic_terminal_width() {
    1111        cmd.arg(format!("--diagnostic-width={width}"));
    1112    }
    1113}
    1114
    1115/// Adds essential rustc flags and environment variables to the command to execute.
    1116fn build_base_args(
    1117    build_runner: &BuildRunner<'_, '_>,
    1118    cmd: &mut ProcessBuilder,
    1119    unit: &Unit,
    1120) -> CargoResult<()> {
    1121    assert!(!unit.mode.is_run_custom_build());
    1122
    1123    let bcx = build_runner.bcx;
    1124    let Profile {
    1125        ref opt_level,
    1126        codegen_backend,
    1127        codegen_units,
    1128        debuginfo,
    1129        debug_assertions,
    1130        split_debuginfo,
    1131        overflow_checks,
    1132        rpath,
    1133        ref panic,
    1134        incremental,
    1135        strip,
    1136        rustflags: profile_rustflags,
    1137        trim_paths,
    1138        hint_mostly_unused,
    1139        ..
    1140    } = unit.profile.clone();
    1141    let test = unit.mode.is_any_test();
    1142
    1143    cmd.arg("--crate-name").arg(&unit.target.crate_name());
    1144
    1145    let edition = unit.target.edition();
    1146    edition.cmd_edition_arg(cmd);
    1147
    1148    add_path_args(bcx.ws, unit, cmd);
    1149    add_error_format_and_color(build_runner, cmd);
    1150    add_allow_features(build_runner, cmd);
    1151
    1152    let mut contains_dy_lib = false;
    1153    if !test {
    1154        for crate_type in &unit.target.rustc_crate_types() {
    1155            cmd.arg("--crate-type").arg(crate_type.as_str());
    1156            contains_dy_lib |= crate_type == &CrateType::Dylib;
    1157        }
    1158    }
    1159
    1160    if unit.mode.is_check() {
    1161        cmd.arg("--emit=dep-info,metadata");
    1162    } else if build_runner.bcx.gctx.cli_unstable().no_embed_metadata {
    1163        // Nightly rustc supports the -Zembed-metadata=no flag, which tells it to avoid including
    1164        // full metadata in rlib/dylib artifacts, to save space on disk. In this case, metadata
    1165        // will only be stored in .rmeta files.
    1166        // When we use this flag, we should also pass --emit=metadata to all artifacts that
    1167        // contain useful metadata (rlib/dylib/proc macros), so that a .rmeta file is actually
    1168        // generated. If we didn't do this, the full metadata would not get written anywhere.
    1169        // However, we do not want to pass --emit=metadata to artifacts that never produce useful
    1170        // metadata, such as binaries, because that would just unnecessarily create empty .rmeta
    1171        // files on disk.
    1172        if unit.benefits_from_no_embed_metadata() {
    1173            cmd.arg("--emit=dep-info,metadata,link");
    1174            cmd.args(&["-Z", "embed-metadata=no"]);
    1175        } else {
    1176            cmd.arg("--emit=dep-info,link");
    1177        }
    1178    } else {
    1179        // If we don't use -Zembed-metadata=no, we emit .rmeta files only for rlib outputs.
    1180        // This metadata may be used in this session for a pipelined compilation, or it may
    1181        // be used in a future Cargo session as part of a pipelined compile.
    1182        if !unit.requires_upstream_objects() {
    1183            cmd.arg("--emit=dep-info,metadata,link");
    1184        } else {
    1185            cmd.arg("--emit=dep-info,link");
    1186        }
    1187    }
    1188
    1189    let prefer_dynamic = (unit.target.for_host() && !unit.target.is_custom_build())
    1190        || (contains_dy_lib && !build_runner.is_primary_package(unit));
    1191    if prefer_dynamic {
    1192        cmd.arg("-C").arg("prefer-dynamic");
    1193    }
    1194
    1195    if opt_level.as_str() != "0" {
    1196        cmd.arg("-C").arg(&format!("opt-level={}", opt_level));
    1197    }
    1198
    1199    if *panic != PanicStrategy::Unwind {
    1200        cmd.arg("-C").arg(format!("panic={}", panic));
    1201    }
    1202
    1203    cmd.args(&lto_args(build_runner, unit));
    1204
    1205    if let Some(backend) = codegen_backend {
    1206        cmd.arg("-Z").arg(&format!("codegen-backend={}", backend));
    1207    }
    1208
    1209    if let Some(n) = codegen_units {
    1210        cmd.arg("-C").arg(&format!("codegen-units={}", n));
    1211    }
    1212
    1213    let debuginfo = debuginfo.into_inner();
    1214    // Shorten the number of arguments if possible.
    1215    if debuginfo != TomlDebugInfo::None {
    1216        cmd.arg("-C").arg(format!("debuginfo={debuginfo}"));
    1217        // This is generally just an optimization on build time so if we don't
    1218        // pass it then it's ok. The values for the flag (off, packed, unpacked)
    1219        // may be supported or not depending on the platform, so availability is
    1220        // checked per-value. For example, at the time of writing this code, on
    1221        // Windows the only stable valid value for split-debuginfo is "packed",
    1222        // while on Linux "unpacked" is also stable.
    1223        if let Some(split) = split_debuginfo {
    1224            if build_runner
    1225                .bcx
    1226                .target_data
    1227                .info(unit.kind)
    1228                .supports_debuginfo_split(split)
    1229            {
    1230                cmd.arg("-C").arg(format!("split-debuginfo={split}"));
    1231            }
    1232        }
    1233    }
    1234
    1235    if let Some(trim_paths) = trim_paths {
    1236        trim_paths_args(cmd, build_runner, unit, &trim_paths)?;
    1237    }
    1238
    1239    cmd.args(unit.pkg.manifest().lint_rustflags());
    1240    cmd.args(&profile_rustflags);
    1241
    1242    // `-C overflow-checks` is implied by the setting of `-C debug-assertions`,
    1243    // so we only need to provide `-C overflow-checks` if it differs from
    1244    // the value of `-C debug-assertions` we would provide.
    1245    if opt_level.as_str() != "0" {
    1246        if debug_assertions {
    1247            cmd.args(&["-C", "debug-assertions=on"]);
    1248            if !overflow_checks {
    1249                cmd.args(&["-C", "overflow-checks=off"]);
    1250            }
    1251        } else if overflow_checks {
    1252            cmd.args(&["-C", "overflow-checks=on"]);
    1253        }
    1254    } else if !debug_assertions {
    1255        cmd.args(&["-C", "debug-assertions=off"]);
    1256        if overflow_checks {
    1257            cmd.args(&["-C", "overflow-checks=on"]);
    1258        }
    1259    } else if !overflow_checks {
    1260        cmd.args(&["-C", "overflow-checks=off"]);
    1261    }
    1262
    1263    if test && unit.target.harness() {
    1264        cmd.arg("--test");
    1265
    1266        // Cargo has historically never compiled `--test` binaries with
    1267        // `panic=abort` because the `test` crate itself didn't support it.
    1268        // Support is now upstream, however, but requires an unstable flag to be
    1269        // passed when compiling the test. We require, in Cargo, an unstable
    1270        // flag to pass to rustc, so register that here. Eventually this flag
    1271        // will simply not be needed when the behavior is stabilized in the Rust
    1272        // compiler itself.
    1273        if *panic == PanicStrategy::Abort {
    1274            cmd.arg("-Z").arg("panic-abort-tests");
    1275        }
    1276    } else if test {
    1277        cmd.arg("--cfg").arg("test");
    1278    }
    1279
    1280    cmd.args(&features_args(unit));
    1281    cmd.args(&check_cfg_args(unit));
    1282
    1283    let meta = build_runner.files().metadata(unit);
    1284    cmd.arg("-C")
    1285        .arg(&format!("metadata={}", meta.c_metadata()));
    1286    if let Some(c_extra_filename) = meta.c_extra_filename() {
    1287        cmd.arg("-C")
    1288            .arg(&format!("extra-filename=-{c_extra_filename}"));
    1289    }
    1290
    1291    if rpath {
    1292        cmd.arg("-C").arg("rpath");
    1293    }
    1294
    1295    cmd.arg("--out-dir")
    1296        .arg(&build_runner.files().out_dir(unit));
    1297
    1298    fn opt(cmd: &mut ProcessBuilder, key: &str, prefix: &str, val: Option<&OsStr>) {
    1299        if let Some(val) = val {
    1300            let mut joined = OsString::from(prefix);
    1301            joined.push(val);
    1302            cmd.arg(key).arg(joined);
    1303        }
    1304    }
    1305
    1306    if let CompileKind::Target(n) = unit.kind {
    1307        cmd.arg("--target").arg(n.rustc_target());
    1308    }
    1309
    1310    opt(
    1311        cmd,
    1312        "-C",
    1313        "linker=",
    1314        build_runner
    1315            .compilation
    1316            .target_linker(unit.kind)
    1317            .as_ref()
    1318            .map(|s| s.as_ref()),
    1319    );
    1320    if incremental {
    1321        let dir = build_runner
    1322            .files()
    1323            .layout(unit.kind)
    1324            .incremental()
    1325            .as_os_str();
    1326        opt(cmd, "-C", "incremental=", Some(dir));
    1327    }
    1328
    1329    if hint_mostly_unused {
    1330        if bcx.gctx.cli_unstable().profile_hint_mostly_unused {
    1331            cmd.arg("-Zhint-mostly-unused");
    1332        } else {
    1333            bcx.gctx
    1334                .shell()
    1335                .warn("ignoring 'hint-mostly-unused' profile option, pass `-Zprofile-hint-mostly-unused` to enable it")?;
    1336        }
    1337    }
    1338
    1339    let strip = strip.into_inner();
    1340    if strip != StripInner::None {
    1341        cmd.arg("-C").arg(format!("strip={}", strip));
    1342    }
    1343
    1344    if unit.is_std {
    1345        // -Zforce-unstable-if-unmarked prevents the accidental use of
    1346        // unstable crates within the sysroot (such as "extern crate libc" or
    1347        // any non-public crate in the sysroot).
    1348        //
    1349        // RUSTC_BOOTSTRAP allows unstable features on stable.
    1350        cmd.arg("-Z")
    1351            .arg("force-unstable-if-unmarked")
    1352            .env("RUSTC_BOOTSTRAP", "1");
    1353    }
    1354
    1355    // Add `CARGO_BIN_EXE_` environment variables for building tests.
    1356    if unit.target.is_test() || unit.target.is_bench() {
    1357        for bin_target in unit
    1358            .pkg
    1359            .manifest()
    1360            .targets()
    1361            .iter()
    1362            .filter(|target| target.is_bin())
    1363        {
    1364            let exe_path = build_runner.files().bin_link_for_target(
    1365                bin_target,
    1366                unit.kind,
    1367                build_runner.bcx,
    1368            )?;
    1369            let name = bin_target
    1370                .binary_filename()
    1371                .unwrap_or(bin_target.name().to_string());
    1372            let key = format!("CARGO_BIN_EXE_{}", name);
    1373            cmd.env(&key, exe_path);
    1374        }
    1375    }
    1376    Ok(())
    1377}
    1378
    1379/// All active features for the unit passed as `--cfg features=<feature-name>`.
    1380fn features_args(unit: &Unit) -> Vec<OsString> {
    1381    let mut args = Vec::with_capacity(unit.features.len() * 2);
    1382
    1383    for feat in &unit.features {
    1384        args.push(OsString::from("--cfg"));
    1385        args.push(OsString::from(format!("feature=\"{}\"", feat)));
    1386    }
    1387
    1388    args
    1389}
    1390
    1391/// Like [`trim_paths_args`] but for rustdoc invocations.
    1392fn trim_paths_args_rustdoc(
    1393    cmd: &mut ProcessBuilder,
    1394    build_runner: &BuildRunner<'_, '_>,
    1395    unit: &Unit,
    1396    trim_paths: &TomlTrimPaths,
    1397) -> CargoResult<()> {
    1398    match trim_paths {
    1399        // rustdoc supports diagnostics trimming only.
    1400        TomlTrimPaths::Values(values) if !values.contains(&TomlTrimPathsValue::Diagnostics) => {
    1401            return Ok(())
    1402        }
    1403        _ => {}
    1404    }
    1405
    1406    // feature gate was checked during manifest/config parsing.
    1407    cmd.arg("-Zunstable-options");
    1408
    1409    // Order of `--remap-path-prefix` flags is important for `-Zbuild-std`.
    1410    // We want to show `/rustc/<hash>/library/std` instead of `std-0.0.0`.
    1411    cmd.arg(package_remap(build_runner, unit));
    1412    cmd.arg(build_dir_remap(build_runner));
    1413    cmd.arg(sysroot_remap(build_runner, unit));
    1414
    1415    Ok(())
    1416}
    1417
    1418/// Generates the `--remap-path-scope` and `--remap-path-prefix` for [RFC 3127].
    1419/// See also unstable feature [`-Ztrim-paths`].
    1420///
    1421/// [RFC 3127]: https://rust-lang.github.io/rfcs/3127-trim-paths.html
    1422/// [`-Ztrim-paths`]: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#profile-trim-paths-option
    1423fn trim_paths_args(
    1424    cmd: &mut ProcessBuilder,
    1425    build_runner: &BuildRunner<'_, '_>,
    1426    unit: &Unit,
    1427    trim_paths: &TomlTrimPaths,
    1428) -> CargoResult<()> {
    1429    if trim_paths.is_none() {
    1430        return Ok(());
    1431    }
    1432
    1433    // feature gate was checked during manifest/config parsing.
    1434    cmd.arg("-Zunstable-options");
    1435    cmd.arg(format!("-Zremap-path-scope={trim_paths}"));
    1436
    1437    // Order of `--remap-path-prefix` flags is important for `-Zbuild-std`.
    1438    // We want to show `/rustc/<hash>/library/std` instead of `std-0.0.0`.
    1439    cmd.arg(package_remap(build_runner, unit));
    1440    cmd.arg(build_dir_remap(build_runner));
    1441    cmd.arg(sysroot_remap(build_runner, unit));
    1442
    1443    Ok(())
    1444}
    1445
    1446/// Path prefix remap rules for sysroot.
    1447///
    1448/// This remap logic aligns with rustc:
    1449/// <https://github.com/rust-lang/rust/blob/c2ef3516/src/bootstrap/src/lib.rs#L1113-L1116>
    1450fn sysroot_remap(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> OsString {
    1451    let mut remap = OsString::from("--remap-path-prefix=");
    1452    remap.push({
    1453        // See also `detect_sysroot_src_path()`.
    1454        let mut sysroot = build_runner.bcx.target_data.info(unit.kind).sysroot.clone();
    1455        sysroot.push("lib");
    1456        sysroot.push("rustlib");
    1457        sysroot.push("src");
    1458        sysroot.push("rust");
    1459        sysroot
    1460    });
    1461    remap.push("=");
    1462    remap.push("/rustc/");
    1463    if let Some(commit_hash) = build_runner.bcx.rustc().commit_hash.as_ref() {
    1464        remap.push(commit_hash);
    1465    } else {
    1466        remap.push(build_runner.bcx.rustc().version.to_string());
    1467    }
    1468    remap
    1469}
    1470
    1471/// Path prefix remap rules for dependencies.
    1472///
    1473/// * Git dependencies: remove `~/.cargo/git/checkouts` prefix.
    1474/// * Registry dependencies: remove `~/.cargo/registry/src` prefix.
    1475/// * Others (e.g. path dependencies):
    1476///     * relative paths to workspace root if inside the workspace directory.
    1477///     * otherwise remapped to `<pkg>-<version>`.
    1478fn package_remap(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> OsString {
    1479    let pkg_root = unit.pkg.root();
    1480    let ws_root = build_runner.bcx.ws.root();
    1481    let mut remap = OsString::from("--remap-path-prefix=");
    1482    let source_id = unit.pkg.package_id().source_id();
    1483    if source_id.is_git() {
    1484        remap.push(
    1485            build_runner
    1486                .bcx
    1487                .gctx
    1488                .git_checkouts_path()
    1489                .as_path_unlocked(),
    1490        );
    1491        remap.push("=");
    1492    } else if source_id.is_registry() {
    1493        remap.push(
    1494            build_runner
    1495                .bcx
    1496                .gctx
    1497                .registry_source_path()
    1498                .as_path_unlocked(),
    1499        );
    1500        remap.push("=");
    1501    } else if pkg_root.strip_prefix(ws_root).is_ok() {
    1502        remap.push(ws_root);
    1503        remap.push("=."); // remap to relative rustc work dir explicitly
    1504    } else {
    1505        remap.push(pkg_root);
    1506        remap.push("=");
    1507        remap.push(unit.pkg.name());
    1508        remap.push("-");
    1509        remap.push(unit.pkg.version().to_string());
    1510    }
    1511    remap
    1512}
    1513
    1514/// Remap all paths pointing to `build.build-dir`,
    1515/// i.e., `[BUILD_DIR]/debug/deps/foo-[HASH].dwo` would be remapped to
    1516/// `/cargo/build-dir/debug/deps/foo-[HASH].dwo`
    1517/// (note the `/cargo/build-dir` prefix).
    1518///
    1519/// This covers scenarios like:
    1520///
    1521/// * Build script generated code. For example, a build script may call `file!`
    1522///   macros, and the associated crate uses [`include!`] to include the expanded
    1523///   [`file!`] macro in-place via the `OUT_DIR` environment.
    1524/// * On Linux, `DW_AT_GNU_dwo_name` that contains paths to split debuginfo
    1525///   files (dwp and dwo).
    1526fn build_dir_remap(build_runner: &BuildRunner<'_, '_>) -> OsString {
    1527    let build_dir = build_runner.bcx.ws.build_dir();
    1528    let mut remap = OsString::from("--remap-path-prefix=");
    1529    remap.push(build_dir.as_path_unlocked());
    1530    remap.push("=/cargo/build-dir");
    1531    remap
    1532}
    1533
    1534/// Generates the `--check-cfg` arguments for the `unit`.
    1535fn check_cfg_args(unit: &Unit) -> Vec<OsString> {
    1536    // The routine below generates the --check-cfg arguments. Our goals here are to
    1537    // enable the checking of conditionals and pass the list of declared features.
    1538    //
    1539    // In the simplified case, it would resemble something like this:
    1540    //
    1541    //   --check-cfg=cfg() --check-cfg=cfg(feature, values(...))
    1542    //
    1543    // but having `cfg()` is redundant with the second argument (as well-known names
    1544    // and values are implicitly enabled when one or more `--check-cfg` argument is
    1545    // passed) so we don't emit it and just pass:
    1546    //
    1547    //   --check-cfg=cfg(feature, values(...))
    1548    //
    1549    // This way, even if there are no declared features, the config `feature` will
    1550    // still be expected, meaning users would get "unexpected value" instead of name.
    1551    // This wasn't always the case, see rust-lang#119930 for some details.
    1552
    1553    let gross_cap_estimation = unit.pkg.summary().features().len() * 7 + 25;
    1554    let mut arg_feature = OsString::with_capacity(gross_cap_estimation);
    1555
    1556    arg_feature.push("cfg(feature, values(");
    1557    for (i, feature) in unit.pkg.summary().features().keys().enumerate() {
    1558        if i != 0 {
    1559            arg_feature.push(", ");
    1560        }
    1561        arg_feature.push("\"");
    1562        arg_feature.push(feature);
    1563        arg_feature.push("\"");
    1564    }
    1565    arg_feature.push("))");
    1566
    1567    // In addition to the package features, we also include the `test` cfg (since
    1568    // compiler-team#785, as to be able to someday apply yt conditionally), as well
    1569    // the `docsrs` cfg from the docs.rs service.
    1570    //
    1571    // We include `docsrs` here (in Cargo) instead of rustc, since there is a much closer
    1572    // relationship between Cargo and docs.rs than rustc and docs.rs. In particular, all
    1573    // users of docs.rs use Cargo, but not all users of rustc (like Rust-for-Linux) use docs.rs.
    1574
    1575    vec![
    1576        OsString::from("--check-cfg"),
    1577        OsString::from("cfg(docsrs,test)"),
    1578        OsString::from("--check-cfg"),
    1579        arg_feature,
    1580    ]
    1581}
    1582
    1583/// Adds LTO related codegen flags.
    1584fn lto_args(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> Vec<OsString> {
    1585    let mut result = Vec::new();
    1586    let mut push = |arg: &str| {
    1587        result.push(OsString::from("-C"));
    1588        result.push(OsString::from(arg));
    1589    };
    1590    match build_runner.lto[unit] {
    1591        lto::Lto::Run(None) => push("lto"),
    1592        lto::Lto::Run(Some(s)) => push(&format!("lto={}", s)),
    1593        lto::Lto::Off => {
    1594            push("lto=off");
    1595            push("embed-bitcode=no");
    1596        }
    1597        lto::Lto::ObjectAndBitcode => {} // this is rustc's default
    1598        lto::Lto::OnlyBitcode => push("linker-plugin-lto"),
    1599        lto::Lto::OnlyObject => push("embed-bitcode=no"),
    1600    }
    1601    result
    1602}
    1603
    1604/// Adds dependency-relevant rustc flags and environment variables
    1605/// to the command to execute, such as [`-L`] and [`--extern`].
    1606///
    1607/// [`-L`]: https://doc.rust-lang.org/nightly/rustc/command-line-arguments.html#-l-add-a-directory-to-the-library-search-path
    1608/// [`--extern`]: https://doc.rust-lang.org/nightly/rustc/command-line-arguments.html#--extern-specify-where-an-external-library-is-located
    1609fn build_deps_args(
    1610    cmd: &mut ProcessBuilder,
    1611    build_runner: &BuildRunner<'_, '_>,
    1612    unit: &Unit,
    1613) -> CargoResult<()> {
    1614    let bcx = build_runner.bcx;
    1615    cmd.arg("-L").arg(&{
    1616        let mut deps = OsString::from("dependency=");
    1617        deps.push(build_runner.files().deps_dir(unit));
    1618        deps
    1619    });
    1620
    1621    // Be sure that the host path is also listed. This'll ensure that proc macro
    1622    // dependencies are correctly found (for reexported macros).
    1623    if !unit.kind.is_host() {
    1624        cmd.arg("-L").arg(&{
    1625            let mut deps = OsString::from("dependency=");
    1626            deps.push(build_runner.files().host_deps());
    1627            deps
    1628        });
    1629    }
    1630
    1631    let deps = build_runner.unit_deps(unit);
    1632
    1633    // If there is not one linkable target but should, rustc fails later
    1634    // on if there is an `extern crate` for it. This may turn into a hard
    1635    // error in the future (see PR #4797).
    1636    if !deps
    1637        .iter()
    1638        .any(|dep| !dep.unit.mode.is_doc() && dep.unit.target.is_linkable())
    1639    {
    1640        if let Some(dep) = deps.iter().find(|dep| {
    1641            !dep.unit.mode.is_doc() && dep.unit.target.is_lib() && !dep.unit.artifact.is_true()
    1642        }) {
    1643            bcx.gctx.shell().warn(format!(
    1644                "The package `{}` \
    1645                 provides no linkable target. The compiler might raise an error while compiling \
    1646                 `{}`. Consider adding 'dylib' or 'rlib' to key `crate-type` in `{}`'s \
    1647                 Cargo.toml. This warning might turn into a hard error in the future.",
    1648                dep.unit.target.crate_name(),
    1649                unit.target.crate_name(),
    1650                dep.unit.target.crate_name()
    1651            ))?;
    1652        }
    1653    }
    1654
    1655    let mut unstable_opts = false;
    1656
    1657    for dep in deps {
    1658        if dep.unit.mode.is_run_custom_build() {
    1659            cmd.env(
    1660                "OUT_DIR",
    1661                &build_runner.files().build_script_out_dir(&dep.unit),
    1662            );
    1663        }
    1664    }
    1665
    1666    for arg in extern_args(build_runner, unit, &mut unstable_opts)? {
    1667        cmd.arg(arg);
    1668    }
    1669
    1670    for (var, env) in artifact::get_env(build_runner, deps)? {
    1671        cmd.env(&var, env);
    1672    }
    1673
    1674    // This will only be set if we're already using a feature
    1675    // requiring nightly rust
    1676    if unstable_opts {
    1677        cmd.arg("-Z").arg("unstable-options");
    1678    }
    1679
    1680    Ok(())
    1681}
    1682
    1683/// Adds extra rustc flags and environment variables collected from the output
    1684/// of a build-script to the command to execute, include custom environment
    1685/// variables and `cfg`.
    1686fn add_custom_flags(
    1687    cmd: &mut ProcessBuilder,
    1688    build_script_outputs: &BuildScriptOutputs,
    1689    metadata: Option<UnitHash>,
    1690) -> CargoResult<()> {
    1691    if let Some(metadata) = metadata {
    1692        if let Some(output) = build_script_outputs.get(metadata) {
    1693            for cfg in output.cfgs.iter() {
    1694                cmd.arg("--cfg").arg(cfg);
    1695            }
    1696            for check_cfg in &output.check_cfgs {
    1697                cmd.arg("--check-cfg").arg(check_cfg);
    1698            }
    1699            for (name, value) in output.env.iter() {
    1700                cmd.env(name, value);
    1701            }
    1702        }
    1703    }
    1704
    1705    Ok(())
    1706}
    1707
    1708/// Generates a list of `--extern` arguments.
    1709pub fn extern_args(
    1710    build_runner: &BuildRunner<'_, '_>,
    1711    unit: &Unit,
    1712    unstable_opts: &mut bool,
    1713) -> CargoResult<Vec<OsString>> {
    1714    let mut result = Vec::new();
    1715    let deps = build_runner.unit_deps(unit);
    1716
    1717    let no_embed_metadata = build_runner.bcx.gctx.cli_unstable().no_embed_metadata;
    1718
    1719    // Closure to add one dependency to `result`.
    1720    let mut link_to =
    1721        |dep: &UnitDep, extern_crate_name: InternedString, noprelude: bool| -> CargoResult<()> {
    1722            let mut value = OsString::new();
    1723            let mut opts = Vec::new();
    1724            let is_public_dependency_enabled = unit
    1725                .pkg
    1726                .manifest()
    1727                .unstable_features()
    1728                .require(Feature::public_dependency())
    1729                .is_ok()
    1730                || build_runner.bcx.gctx.cli_unstable().public_dependency;
    1731            if !dep.public && unit.target.is_lib() && is_public_dependency_enabled {
    1732                opts.push("priv");
    1733                *unstable_opts = true;
    1734            }
    1735            if noprelude {
    1736                opts.push("noprelude");
    1737                *unstable_opts = true;
    1738            }
    1739            if !opts.is_empty() {
    1740                value.push(opts.join(","));
    1741                value.push(":");
    1742            }
    1743            value.push(extern_crate_name.as_str());
    1744            value.push("=");
    1745
    1746            let mut pass = |file| {
    1747                let mut value = value.clone();
    1748                value.push(file);
    1749                result.push(OsString::from("--extern"));
    1750                result.push(value);
    1751            };
    1752
    1753            let outputs = build_runner.outputs(&dep.unit)?;
    1754
    1755            if build_runner.only_requires_rmeta(unit, &dep.unit) || dep.unit.mode.is_check() {
    1756                // Example: rlib dependency for an rlib, rmeta is all that is required.
    1757                let output = outputs
    1758                    .iter()
    1759                    .find(|output| output.flavor == FileFlavor::Rmeta)
    1760                    .expect("failed to find rmeta dep for pipelined dep");
    1761                pass(&output.path);
    1762            } else {
    1763                // Example: a bin needs `rlib` for dependencies, it cannot use rmeta.
    1764                for output in outputs.iter() {
    1765                    if output.flavor == FileFlavor::Linkable {
    1766                        pass(&output.path);
    1767                    }
    1768                    // If we use -Zembed-metadata=no, we also need to pass the path to the
    1769                    // corresponding .rmeta file to the linkable artifact, because the
    1770                    // normal dependency (rlib) doesn't contain the full metadata.
    1771                    else if no_embed_metadata && output.flavor == FileFlavor::Rmeta {
    1772                        pass(&output.path);
    1773                    }
    1774                }
    1775            }
    1776            Ok(())
    1777        };
    1778
    1779    for dep in deps {
    1780        if dep.unit.target.is_linkable() && !dep.unit.mode.is_doc() {
    1781            link_to(dep, dep.extern_crate_name, dep.noprelude)?;
    1782        }
    1783    }
    1784    if unit.target.proc_macro() {
    1785        // Automatically import `proc_macro`.
    1786        result.push(OsString::from("--extern"));
    1787        result.push(OsString::from("proc_macro"));
    1788    }
    1789
    1790    Ok(result)
    1791}
    1792
    1793fn envify(s: &str) -> String {
    1794    s.chars()
    1795        .flat_map(|c| c.to_uppercase())
    1796        .map(|c| if c == '-' { '_' } else { c })
    1797        .collect()
    1798}
    1799
    1800/// Configuration of the display of messages emitted by the compiler,
    1801/// e.g. diagnostics, warnings, errors, and message caching.
    1802struct OutputOptions {
    1803    /// What format we're emitting from Cargo itself.
    1804    format: MessageFormat,
    1805    /// Where to write the JSON messages to support playback later if the unit
    1806    /// is fresh. The file is created lazily so that in the normal case, lots
    1807    /// of empty files are not created. If this is None, the output will not
    1808    /// be cached (such as when replaying cached messages).
    1809    cache_cell: Option<(PathBuf, LazyCell<File>)>,
    1810    /// If `true`, display any diagnostics.
    1811    /// Other types of JSON messages are processed regardless
    1812    /// of the value of this flag.
    1813    ///
    1814    /// This is used primarily for cache replay. If you build with `-vv`, the
    1815    /// cache will be filled with diagnostics from dependencies. When the
    1816    /// cache is replayed without `-vv`, we don't want to show them.
    1817    show_diagnostics: bool,
    1818    /// Tracks the number of warnings we've seen so far.
    1819    warnings_seen: usize,
    1820    /// Tracks the number of errors we've seen so far.
    1821    errors_seen: usize,
    1822}
    1823
    1824impl OutputOptions {
    1825    fn new(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> OutputOptions {
    1826        let path = build_runner.files().message_cache_path(unit);
    1827        // Remove old cache, ignore ENOENT, which is the common case.
    1828        drop(fs::remove_file(&path));
    1829        let cache_cell = Some((path, LazyCell::new()));
    1830        let show_diagnostics =
    1831            build_runner.bcx.gctx.warning_handling().unwrap_or_default() != WarningHandling::Allow;
    1832        OutputOptions {
    1833            format: build_runner.bcx.build_config.message_format,
    1834            cache_cell,
    1835            show_diagnostics,
    1836            warnings_seen: 0,
    1837            errors_seen: 0,
    1838        }
    1839    }
    1840}
    1841
    1842fn on_stdout_line(
    1843    state: &JobState<'_, '_>,
    1844    line: &str,
    1845    _package_id: PackageId,
    1846    _target: &Target,
    1847) -> CargoResult<()> {
    1848    state.stdout(line.to_string())?;
    1849    Ok(())
    1850}
    1851
    1852fn on_stderr_line(
    1853    state: &JobState<'_, '_>,
    1854    line: &str,
    1855    package_id: PackageId,
    1856    manifest_path: &std::path::Path,
    1857    target: &Target,
    1858    options: &mut OutputOptions,
    1859) -> CargoResult<()> {
    1860    if on_stderr_line_inner(state, line, package_id, manifest_path, target, options)? {
    1861        // Check if caching is enabled.
    1862        if let Some((path, cell)) = &mut options.cache_cell {
    1863            // Cache the output, which will be replayed later when Fresh.
    1864            let f = cell.try_borrow_mut_with(|| paths::create(path))?;
    1865            debug_assert!(!line.contains('\n'));
    1866            f.write_all(line.as_bytes())?;
    1867            f.write_all(&[b'\n'])?;
    1868        }
    1869    }
    1870    Ok(())
    1871}
    1872
    1873/// Returns true if the line should be cached.
    1874fn on_stderr_line_inner(
    1875    state: &JobState<'_, '_>,
    1876    line: &str,
    1877    package_id: PackageId,
    1878    manifest_path: &std::path::Path,
    1879    target: &Target,
    1880    options: &mut OutputOptions,
    1881) -> CargoResult<bool> {
    1882    // We primarily want to use this function to process JSON messages from
    1883    // rustc. The compiler should always print one JSON message per line, and
    1884    // otherwise it may have other output intermingled (think RUST_LOG or
    1885    // something like that), so skip over everything that doesn't look like a
    1886    // JSON message.
    1887    if !line.starts_with('{') {
    1888        state.stderr(line.to_string())?;
    1889        return Ok(true);
    1890    }
    1891
    1892    let mut compiler_message: Box<serde_json::value::RawValue> = match serde_json::from_str(line) {
    1893        Ok(msg) => msg,
    1894
    1895        // If the compiler produced a line that started with `{` but it wasn't
    1896        // valid JSON, maybe it wasn't JSON in the first place! Forward it along
    1897        // to stderr.
    1898        Err(e) => {
    1899            debug!("failed to parse json: {:?}", e);
    1900            state.stderr(line.to_string())?;
    1901            return Ok(true);
    1902        }
    1903    };
    1904
    1905    let count_diagnostic = |level, options: &mut OutputOptions| {
    1906        if level == "warning" {
    1907            options.warnings_seen += 1;
    1908        } else if level == "error" {
    1909            options.errors_seen += 1;
    1910        }
    1911    };
    1912
    1913    if let Ok(report) = serde_json::from_str::<FutureIncompatReport>(compiler_message.get()) {
    1914        for item in &report.future_incompat_report {
    1915            count_diagnostic(&*item.diagnostic.level, options);
    1916        }
    1917        state.future_incompat_report(report.future_incompat_report);
    1918        return Ok(true);
    1919    }
    1920
    1921    // Depending on what we're emitting from Cargo itself, we figure out what to
    1922    // do with this JSON message.
    1923    match options.format {
    1924        // In the "human" output formats (human/short) or if diagnostic messages
    1925        // from rustc aren't being included in the output of Cargo's JSON
    1926        // messages then we extract the diagnostic (if present) here and handle
    1927        // it ourselves.
    1928        MessageFormat::Human
    1929        | MessageFormat::Short
    1930        | MessageFormat::Json {
    1931            render_diagnostics: true,
    1932            ..
    1933        } => {
    1934            #[derive(serde::Deserialize)]
    1935            struct CompilerMessage<'a> {
    1936                // `rendered` contains escape sequences, which can't be
    1937                // zero-copy deserialized by serde_json.
    1938                // See https://github.com/serde-rs/json/issues/742
    1939                rendered: String,
    1940                #[serde(borrow)]
    1941                message: Cow<'a, str>,
    1942                #[serde(borrow)]
    1943                level: Cow<'a, str>,
    1944                children: Vec<PartialDiagnostic>,
    1945            }
    1946
    1947            // A partial rustfix::diagnostics::Diagnostic. We deserialize only a
    1948            // subset of the fields because rustc's output can be extremely
    1949            // deeply nested JSON in pathological cases involving macro
    1950            // expansion. Rustfix's Diagnostic struct is recursive containing a
    1951            // field `children: Vec<Self>`, and it can cause deserialization to
    1952            // hit serde_json's default recursion limit, or overflow the stack
    1953            // if we turn that off. Cargo only cares about the 1 field listed
    1954            // here.
    1955            #[derive(serde::Deserialize)]
    1956            struct PartialDiagnostic {
    1957                spans: Vec<PartialDiagnosticSpan>,
    1958            }
    1959
    1960            // A partial rustfix::diagnostics::DiagnosticSpan.
    1961            #[derive(serde::Deserialize)]
    1962            struct PartialDiagnosticSpan {
    1963                suggestion_applicability: Option<Applicability>,
    1964            }
    1965
    1966            if let Ok(mut msg) = serde_json::from_str::<CompilerMessage<'_>>(compiler_message.get())
    1967            {
    1968                if msg.message.starts_with("aborting due to")
    1969                    || msg.message.ends_with("warning emitted")
    1970                    || msg.message.ends_with("warnings emitted")
    1971                {
    1972                    // Skip this line; we'll print our own summary at the end.
    1973                    return Ok(true);
    1974                }
    1975                // state.stderr will add a newline
    1976                if msg.rendered.ends_with('\n') {
    1977                    msg.rendered.pop();
    1978                }
    1979                let rendered = msg.rendered;
    1980                if options.show_diagnostics {
    1981                    let machine_applicable: bool = msg
    1982                        .children
    1983                        .iter()
    1984                        .map(|child| {
    1985                            child
    1986                                .spans
    1987                                .iter()
    1988                                .filter_map(|span| span.suggestion_applicability)
    1989                                .any(|app| app == Applicability::MachineApplicable)
    1990                        })
    1991                        .any(|b| b);
    1992                    count_diagnostic(&msg.level, options);
    1993                    state.emit_diag(&msg.level, rendered, machine_applicable)?;
    1994                }
    1995                return Ok(true);
    1996            }
    1997        }
    1998
    1999        // Remove color information from the rendered string if color is not
    2000        // enabled. Cargo always asks for ANSI colors from rustc. This allows
    2001        // cached replay to enable/disable colors without re-invoking rustc.
    2002        MessageFormat::Json { ansi: false, .. } => {
    2003            #[derive(serde::Deserialize, serde::Serialize)]
    2004            struct CompilerMessage<'a> {
    2005                rendered: String,
    2006                #[serde(flatten, borrow)]
    2007                other: std::collections::BTreeMap<Cow<'a, str>, serde_json::Value>,
    2008            }
    2009            if let Ok(mut error) =
    2010                serde_json::from_str::<CompilerMessage<'_>>(compiler_message.get())
    2011            {
    2012                error.rendered = anstream::adapter::strip_str(&error.rendered).to_string();
    2013                let new_line = serde_json::to_string(&error)?;
    2014                compiler_message = serde_json::value::RawValue::from_string(new_line)?;
    2015            }
    2016        }
    2017
    2018        // If ansi colors are desired then we should be good to go! We can just
    2019        // pass through this message as-is.
    2020        MessageFormat::Json { ansi: true, .. } => {}
    2021    }
    2022
    2023    // We always tell rustc to emit messages about artifacts being produced.
    2024    // These messages feed into pipelined compilation, as well as timing
    2025    // information.
    2026    //
    2027    // Look for a matching directive and inform Cargo internally that a
    2028    // metadata file has been produced.
    2029    #[derive(serde::Deserialize)]
    2030    struct ArtifactNotification<'a> {
    2031        #[serde(borrow)]
    2032        artifact: Cow<'a, str>,
    2033    }
    2034
    2035    if let Ok(artifact) = serde_json::from_str::<ArtifactNotification<'_>>(compiler_message.get()) {
    2036        trace!("found directive from rustc: `{}`", artifact.artifact);
    2037        if artifact.artifact.ends_with(".rmeta") {
    2038            debug!("looks like metadata finished early!");
    2039            state.rmeta_produced();
    2040        }
    2041        return Ok(false);
    2042    }
    2043
    2044    // And failing all that above we should have a legitimate JSON diagnostic
    2045    // from the compiler, so wrap it in an external Cargo JSON message
    2046    // indicating which package it came from and then emit it.
    2047
    2048    if !options.show_diagnostics {
    2049        return Ok(true);
    2050    }
    2051
    2052    #[derive(serde::Deserialize)]
    2053    struct CompilerMessage<'a> {
    2054        #[serde(borrow)]
    2055        message: Cow<'a, str>,
    2056        #[serde(borrow)]
    2057        level: Cow<'a, str>,
    2058    }
    2059
    2060    if let Ok(msg) = serde_json::from_str::<CompilerMessage<'_>>(compiler_message.get()) {
    2061        if msg.message.starts_with("aborting due to")
    2062            || msg.message.ends_with("warning emitted")
    2063            || msg.message.ends_with("warnings emitted")
    2064        {
    2065            // Skip this line; we'll print our own summary at the end.
    2066            return Ok(true);
    2067        }
    2068        count_diagnostic(&msg.level, options);
    2069    }
    2070
    2071    let msg = machine_message::FromCompiler {
    2072        package_id: package_id.to_spec(),
    2073        manifest_path,
    2074        target,
    2075        message: compiler_message,
    2076    }
    2077    .to_json_string();
    2078
    2079    // Switch json lines from rustc/rustdoc that appear on stderr to stdout
    2080    // instead. We want the stdout of Cargo to always be machine parseable as
    2081    // stderr has our colorized human-readable messages.
    2082    state.stdout(msg)?;
    2083    Ok(true)
    2084}
    2085
    2086/// Creates a unit of work that replays the cached compiler message.
    2087///
    2088/// Usually used when a job is fresh and doesn't need to recompile.
    2089fn replay_output_cache(
    2090    package_id: PackageId,
    2091    manifest_path: PathBuf,
    2092    target: &Target,
    2093    path: PathBuf,
    2094    format: MessageFormat,
    2095    show_diagnostics: bool,
    2096) -> Work {
    2097    let target = target.clone();
    2098    let mut options = OutputOptions {
    2099        format,
    2100        cache_cell: None,
    2101        show_diagnostics,
    2102        warnings_seen: 0,
    2103        errors_seen: 0,
    2104    };
    2105    Work::new(move |state| {
    2106        if !path.exists() {
    2107            // No cached output, probably didn't emit anything.
    2108            return Ok(());
    2109        }
    2110        // We sometimes have gigabytes of output from the compiler, so avoid
    2111        // loading it all into memory at once, as that can cause OOM where
    2112        // otherwise there would be none.
    2113        let file = paths::open(&path)?;
    2114        let mut reader = std::io::BufReader::new(file);
    2115        let mut line = String::new();
    2116        loop {
    2117            let length = reader.read_line(&mut line)?;
    2118            if length == 0 {
    2119                break;
    2120            }
    2121            let trimmed = line.trim_end_matches(&['\n', '\r'][..]);
    2122            on_stderr_line(
    2123                state,
    2124                trimmed,
    2125                package_id,
    2126                &manifest_path,
    2127                &target,
    2128                &mut options,
    2129            )?;
    2130            line.clear();
    2131        }
    2132        Ok(())
    2133    })
    2134}
    2135
    2136/// Provides a package name with descriptive target information,
    2137/// e.g., '`foo` (bin "bar" test)', '`foo` (lib doctest)'.
    2138fn descriptive_pkg_name(name: &str, target: &Target, mode: &CompileMode) -> String {
    2139    let desc_name = target.description_named();
    2140    let mode = if mode.is_rustc_test() && !(target.is_test() || target.is_bench()) {
    2141        " test"
    2142    } else if mode.is_doc_test() {
    2143        " doctest"
    2144    } else if mode.is_doc() {
    2145        " doc"
    2146    } else {
    2147        ""
    2148    };
    2149    format!("`{name}` ({desc_name}{mode})")
    2150}
    2151
    2152/// Applies environment variables from config `[env]` to [`ProcessBuilder`].
    2153pub(crate) fn apply_env_config(
    2154    gctx: &crate::GlobalContext,
    2155    cmd: &mut ProcessBuilder,
    2156) -> CargoResult<()> {
    2157    for (key, value) in gctx.env_config()?.iter() {
    2158        // never override a value that has already been set by cargo
    2159        if cmd.get_envs().contains_key(key) {
    2160            continue;
    2161        }
    2162        cmd.env(key, value);
    2163    }
    2164    Ok(())
    2165}
    2166
    2167/// Checks if there are some scrape units waiting to be processed.
    2168fn should_include_scrape_units(bcx: &BuildContext<'_, '_>, unit: &Unit) -> bool {
    2169    unit.mode.is_doc() && bcx.scrape_units.len() > 0 && bcx.ws.unit_needs_doc_scrape(unit)
    2170}
    2171
    2172/// Gets the file path of function call information output from `rustdoc`.
    2173fn scrape_output_path(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> CargoResult<PathBuf> {
    2174    assert!(unit.mode.is_doc() || unit.mode.is_doc_scrape());
    2175    build_runner
    2176        .outputs(unit)
    2177        .map(|outputs| outputs[0].path.clone())
    2178}
    2179
    2180/// Gets the dep-info file emitted by rustdoc.
    2181fn rustdoc_dep_info_loc(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> PathBuf {
    2182    let mut loc = build_runner.files().fingerprint_file_path(unit, "");
    2183    loc.set_extension("d");
    2184    loc
    2185}