src/bootstrap/config.rs

   1 //! Serialized configuration of a build.
   2 //!
   3 //! This module implements parsing `config.toml` configuration files to tweak
   4 //! how the build runs.
   5
   6 use std::cell::{Cell, RefCell};
   7 use std::cmp;
   8 use std::collections::{HashMap, HashSet};
   9 use std::env;
  10 use std::ffi::OsStr;
  11 use std::fmt;
  12 use std::fs;
  13 use std::path::{Path, PathBuf};
  14 use std::process::Command;
  15 use std::str::FromStr;
  16
  17 use crate::builder::{Builder, TaskPath};
  18 use crate::cache::{Interned, INTERNER};
  19 use crate::channel::GitInfo;
  20 pub use crate::flags::Subcommand;
  21 use crate::flags::{Color, Flags};
  22 use crate::util::{exe, output, program_out_of_date, t};
  23 use once_cell::sync::OnceCell;
  24 use serde::{Deserialize, Deserializer};
  25
  26 macro_rules! check_ci_llvm {
  27     ($name:expr) => {
  28         assert!(
  29             $name.is_none(),
  30             "setting {} is incompatible with download-ci-llvm.",
  31             stringify!($name)
  32         );
  33     };
  34 }
  35
  36 /// Global configuration for the entire build and/or bootstrap.
  37 ///
  38 /// This structure is derived from a combination of both `config.toml` and
  39 /// `config.mk`. As of the time of this writing it's unlikely that `config.toml`
  40 /// is used all that much, so this is primarily filled out by `config.mk` which
  41 /// is generated from `./configure`.
  42 ///
  43 /// Note that this structure is not decoded directly into, but rather it is
  44 /// filled out from the decoded forms of the structs below. For documentation
  45 /// each field, see the corresponding fields in
  46 /// `config.toml.example`.
  47 #[derive(Default)]
  48 #[cfg_attr(test, derive(Clone))]
  49 pub struct Config {
  50     pub changelog_seen: Option<usize>,
  51     pub ccache: Option<String>,
  52     /// Call Build::ninja() instead of this.
  53     pub ninja_in_file: bool,
  54     pub verbose: usize,
  55     pub submodules: Option<bool>,
  56     pub compiler_docs: bool,
  57     pub docs_minification: bool,
  58     pub docs: bool,
  59     pub locked_deps: bool,
  60     pub vendor: bool,
  61     pub target_config: HashMap<TargetSelection, Target>,
  62     pub full_bootstrap: bool,
  63     pub extended: bool,
  64     pub tools: Option<HashSet<String>>,
  65     pub sanitizers: bool,
  66     pub profiler: bool,
  67     pub ignore_git: bool,
  68     pub exclude: Vec<TaskPath>,
  69     pub include_default_paths: bool,
  70     pub rustc_error_format: Option<String>,
  71     pub json_output: bool,
  72     pub test_compare_mode: bool,
  73     pub color: Color,
  74     pub patch_binaries_for_nix: bool,
  75     pub stage0_metadata: Stage0Metadata,
  76     /// Whether to use the `c` feature of the `compiler_builtins` crate.
  77     pub optimized_compiler_builtins: bool,
  78
  79     pub on_fail: Option<String>,
  80     pub stage: u32,
  81     pub keep_stage: Vec<u32>,
  82     pub keep_stage_std: Vec<u32>,
  83     pub src: PathBuf,
  84     /// defaults to `config.toml`
  85     pub config: PathBuf,
  86     pub jobs: Option<u32>,
  87     pub cmd: Subcommand,
  88     pub incremental: bool,
  89     pub dry_run: bool,
  90     /// `None` if we shouldn't download CI compiler artifacts, or the commit to download if we should.
  91     #[cfg(not(test))]
  92     download_rustc_commit: Option<String>,
  93     #[cfg(test)]
  94     pub download_rustc_commit: Option<String>,
  95
  96     pub deny_warnings: bool,
  97     pub backtrace_on_ice: bool,
  98
  99     // llvm codegen options
 100     pub llvm_skip_rebuild: bool,
 101     pub llvm_assertions: bool,
 102     pub llvm_tests: bool,
 103     pub llvm_plugins: bool,
 104     pub llvm_optimize: bool,
 105     pub llvm_thin_lto: bool,
 106     pub llvm_release_debuginfo: bool,
 107     pub llvm_version_check: bool,
 108     pub llvm_static_stdcpp: bool,
 109     /// `None` if `llvm_from_ci` is true and we haven't yet downloaded llvm.
 110     #[cfg(not(test))]
 111     llvm_link_shared: Cell<Option<bool>>,
 112     #[cfg(test)]
 113     pub llvm_link_shared: Cell<Option<bool>>,
 114     pub llvm_clang_cl: Option<String>,
 115     pub llvm_targets: Option<String>,
 116     pub llvm_experimental_targets: Option<String>,
 117     pub llvm_link_jobs: Option<u32>,
 118     pub llvm_version_suffix: Option<String>,
 119     pub llvm_use_linker: Option<String>,
 120     pub llvm_allow_old_toolchain: bool,
 121     pub llvm_polly: bool,
 122     pub llvm_clang: bool,
 123     pub llvm_from_ci: bool,
 124     pub llvm_build_config: HashMap<String, String>,
 125
 126     pub use_lld: bool,
 127     pub lld_enabled: bool,
 128     pub llvm_tools_enabled: bool,
 129
 130     pub llvm_cflags: Option<String>,
 131     pub llvm_cxxflags: Option<String>,
 132     pub llvm_ldflags: Option<String>,
 133     pub llvm_use_libcxx: bool,
 134
 135     // rust codegen options
 136     pub rust_optimize: bool,
 137     pub rust_codegen_units: Option<u32>,
 138     pub rust_codegen_units_std: Option<u32>,
 139     pub rust_debug_assertions: bool,
 140     pub rust_debug_assertions_std: bool,
 141     pub rust_overflow_checks: bool,
 142     pub rust_overflow_checks_std: bool,
 143     pub rust_debug_logging: bool,
 144     pub rust_debuginfo_level_rustc: u32,
 145     pub rust_debuginfo_level_std: u32,
 146     pub rust_debuginfo_level_tools: u32,
 147     pub rust_debuginfo_level_tests: u32,
 148     pub rust_split_debuginfo: SplitDebuginfo,
 149     pub rust_rpath: bool,
 150     pub rustc_parallel: bool,
 151     pub rustc_default_linker: Option<String>,
 152     pub rust_optimize_tests: bool,
 153     pub rust_dist_src: bool,
 154     pub rust_codegen_backends: Vec<Interned<String>>,
 155     pub rust_verify_llvm_ir: bool,
 156     pub rust_thin_lto_import_instr_limit: Option<u32>,
 157     pub rust_remap_debuginfo: bool,
 158     pub rust_new_symbol_mangling: Option<bool>,
 159     pub rust_profile_use: Option<String>,
 160     pub rust_profile_generate: Option<String>,
 161     pub llvm_profile_use: Option<String>,
 162     pub llvm_profile_generate: bool,
 163     pub llvm_libunwind_default: Option<LlvmLibunwind>,
 164     pub llvm_bolt_profile_generate: bool,
 165     pub llvm_bolt_profile_use: Option<String>,
 166
 167     pub build: TargetSelection,
 168     pub hosts: Vec<TargetSelection>,
 169     pub targets: Vec<TargetSelection>,
 170     pub local_rebuild: bool,
 171     pub jemalloc: bool,
 172     pub control_flow_guard: bool,
 173
 174     // dist misc
 175     pub dist_sign_folder: Option<PathBuf>,
 176     pub dist_upload_addr: Option<String>,
 177     pub dist_compression_formats: Option<Vec<String>>,
 178
 179     // libstd features
 180     pub backtrace: bool, // support for RUST_BACKTRACE
 181
 182     // misc
 183     pub low_priority: bool,
 184     pub channel: String,
 185     pub description: Option<String>,
 186     pub verbose_tests: bool,
 187     pub save_toolstates: Option<PathBuf>,
 188     pub print_step_timings: bool,
 189     pub print_step_rusage: bool,
 190     pub missing_tools: bool,
 191
 192     // Fallback musl-root for all targets
 193     pub musl_root: Option<PathBuf>,
 194     pub prefix: Option<PathBuf>,
 195     pub sysconfdir: Option<PathBuf>,
 196     pub datadir: Option<PathBuf>,
 197     pub docdir: Option<PathBuf>,
 198     pub bindir: PathBuf,
 199     pub libdir: Option<PathBuf>,
 200     pub mandir: Option<PathBuf>,
 201     pub codegen_tests: bool,
 202     pub nodejs: Option<PathBuf>,
 203     pub npm: Option<PathBuf>,
 204     pub gdb: Option<PathBuf>,
 205     pub python: Option<PathBuf>,
 206     pub cargo_native_static: bool,
 207     pub configure_args: Vec<String>,
 208
 209     // These are either the stage0 downloaded binaries or the locally installed ones.
 210     pub initial_cargo: PathBuf,
 211     pub initial_rustc: PathBuf,
 212     #[cfg(not(test))]
 213     initial_rustfmt: RefCell<RustfmtState>,
 214     #[cfg(test)]
 215     pub initial_rustfmt: RefCell<RustfmtState>,
 216     pub out: PathBuf,
 217 }
 218
 219 #[derive(Default, Deserialize)]
 220 #[cfg_attr(test, derive(Clone))]
 221 pub struct Stage0Metadata {
 222     pub config: Stage0Config,
 223     pub checksums_sha256: HashMap<String, String>,
 224     pub rustfmt: Option<RustfmtMetadata>,
 225 }
 226 #[derive(Default, Deserialize)]
 227 #[cfg_attr(test, derive(Clone))]
 228 pub struct Stage0Config {
 229     pub dist_server: String,
 230     pub artifacts_server: String,
 231     pub artifacts_with_llvm_assertions_server: String,
 232     pub git_merge_commit_email: String,
 233     pub nightly_branch: String,
 234 }
 235 #[derive(Default, Deserialize)]
 236 #[cfg_attr(test, derive(Clone))]
 237 pub struct RustfmtMetadata {
 238     pub date: String,
 239     pub version: String,
 240 }
 241
 242 #[derive(Clone, Debug)]
 243 pub enum RustfmtState {
 244     SystemToolchain(PathBuf),
 245     Downloaded(PathBuf),
 246     Unavailable,
 247     LazyEvaluated,
 248 }
 249
 250 impl Default for RustfmtState {
 251     fn default() -> Self {
 252         RustfmtState::LazyEvaluated
 253     }
 254 }
 255
 256 #[derive(Debug, Clone, Copy, PartialEq)]
 257 pub enum LlvmLibunwind {
 258     No,
 259     InTree,
 260     System,
 261 }
 262
 263 impl Default for LlvmLibunwind {
 264     fn default() -> Self {
 265         Self::No
 266     }
 267 }
 268
 269 impl FromStr for LlvmLibunwind {
 270     type Err = String;
 271
 272     fn from_str(value: &str) -> Result<Self, Self::Err> {
 273         match value {
 274             "no" => Ok(Self::No),
 275             "in-tree" => Ok(Self::InTree),
 276             "system" => Ok(Self::System),
 277             invalid => Err(format!("Invalid value '{}' for rust.llvm-libunwind config.", invalid)),
 278         }
 279     }
 280 }
 281
 282 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 283 pub enum SplitDebuginfo {
 284     Packed,
 285     Unpacked,
 286     Off,
 287 }
 288
 289 impl Default for SplitDebuginfo {
 290     fn default() -> Self {
 291         SplitDebuginfo::Off
 292     }
 293 }
 294
 295 impl std::str::FromStr for SplitDebuginfo {
 296     type Err = ();
 297
 298     fn from_str(s: &str) -> Result<Self, Self::Err> {
 299         match s {
 300             "packed" => Ok(SplitDebuginfo::Packed),
 301             "unpacked" => Ok(SplitDebuginfo::Unpacked),
 302             "off" => Ok(SplitDebuginfo::Off),
 303             _ => Err(()),
 304         }
 305     }
 306 }
 307
 308 impl SplitDebuginfo {
 309     /// Returns the default `-Csplit-debuginfo` value for the current target. See the comment for
 310     /// `rust.split-debuginfo` in `config.toml.example`.
 311     fn default_for_platform(target: &str) -> Self {
 312         if target.contains("apple") {
 313             SplitDebuginfo::Unpacked
 314         } else if target.contains("windows") {
 315             SplitDebuginfo::Packed
 316         } else {
 317             SplitDebuginfo::Off
 318         }
 319     }
 320 }
 321
 322 #[derive(Copy, Clone, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
 323 pub struct TargetSelection {
 324     pub triple: Interned<String>,
 325     file: Option<Interned<String>>,
 326 }
 327
 328 impl TargetSelection {
 329     pub fn from_user(selection: &str) -> Self {
 330         let path = Path::new(selection);
 331
 332         let (triple, file) = if path.exists() {
 333             let triple = path
 334                 .file_stem()
 335                 .expect("Target specification file has no file stem")
 336                 .to_str()
 337                 .expect("Target specification file stem is not UTF-8");
 338
 339             (triple, Some(selection))
 340         } else {
 341             (selection, None)
 342         };
 343
 344         let triple = INTERNER.intern_str(triple);
 345         let file = file.map(|f| INTERNER.intern_str(f));
 346
 347         Self { triple, file }
 348     }
 349
 350     pub fn rustc_target_arg(&self) -> &str {
 351         self.file.as_ref().unwrap_or(&self.triple)
 352     }
 353
 354     pub fn contains(&self, needle: &str) -> bool {
 355         self.triple.contains(needle)
 356     }
 357
 358     pub fn starts_with(&self, needle: &str) -> bool {
 359         self.triple.starts_with(needle)
 360     }
 361
 362     pub fn ends_with(&self, needle: &str) -> bool {
 363         self.triple.ends_with(needle)
 364     }
 365 }
 366
 367 impl fmt::Display for TargetSelection {
 368     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 369         write!(f, "{}", self.triple)?;
 370         if let Some(file) = self.file {
 371             write!(f, "({})", file)?;
 372         }
 373         Ok(())
 374     }
 375 }
 376
 377 impl fmt::Debug for TargetSelection {
 378     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 379         write!(f, "{}", self)
 380     }
 381 }
 382
 383 impl PartialEq<&str> for TargetSelection {
 384     fn eq(&self, other: &&str) -> bool {
 385         self.triple == *other
 386     }
 387 }
 388
 389 /// Per-target configuration stored in the global configuration structure.
 390 #[derive(Default)]
 391 #[cfg_attr(test, derive(Clone))]
 392 pub struct Target {
 393     /// Some(path to llvm-config) if using an external LLVM.
 394     pub llvm_config: Option<PathBuf>,
 395     pub llvm_has_rust_patches: Option<bool>,
 396     /// Some(path to FileCheck) if one was specified.
 397     pub llvm_filecheck: Option<PathBuf>,
 398     pub llvm_libunwind: Option<LlvmLibunwind>,
 399     pub cc: Option<PathBuf>,
 400     pub cxx: Option<PathBuf>,
 401     pub ar: Option<PathBuf>,
 402     pub ranlib: Option<PathBuf>,
 403     pub default_linker: Option<PathBuf>,
 404     pub linker: Option<PathBuf>,
 405     pub ndk: Option<PathBuf>,
 406     pub sanitizers: Option<bool>,
 407     pub profiler: Option<bool>,
 408     pub crt_static: Option<bool>,
 409     pub musl_root: Option<PathBuf>,
 410     pub musl_libdir: Option<PathBuf>,
 411     pub wasi_root: Option<PathBuf>,
 412     pub qemu_rootfs: Option<PathBuf>,
 413     pub no_std: bool,
 414 }
 415
 416 impl Target {
 417     pub fn from_triple(triple: &str) -> Self {
 418         let mut target: Self = Default::default();
 419         if triple.contains("-none")
 420             || triple.contains("nvptx")
 421             || triple.contains("switch")
 422             || triple.contains("-uefi")
 423         {
 424             target.no_std = true;
 425         }
 426         target
 427     }
 428 }
 429 /// Structure of the `config.toml` file that configuration is read from.
 430 ///
 431 /// This structure uses `Decodable` to automatically decode a TOML configuration
 432 /// file into this format, and then this is traversed and written into the above
 433 /// `Config` structure.
 434 #[derive(Deserialize, Default)]
 435 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 436 struct TomlConfig {
 437     changelog_seen: Option<usize>,
 438     build: Option<Build>,
 439     install: Option<Install>,
 440     llvm: Option<Llvm>,
 441     rust: Option<Rust>,
 442     target: Option<HashMap<String, TomlTarget>>,
 443     dist: Option<Dist>,
 444     profile: Option<String>,
 445 }
 446
 447 trait Merge {
 448     fn merge(&mut self, other: Self);
 449 }
 450
 451 impl Merge for TomlConfig {
 452     fn merge(
 453         &mut self,
 454         TomlConfig { build, install, llvm, rust, dist, target, profile: _, changelog_seen: _ }: Self,
 455     ) {
 456         fn do_merge<T: Merge>(x: &mut Option<T>, y: Option<T>) {
 457             if let Some(new) = y {
 458                 if let Some(original) = x {
 459                     original.merge(new);
 460                 } else {
 461                     *x = Some(new);
 462                 }
 463             }
 464         }
 465         do_merge(&mut self.build, build);
 466         do_merge(&mut self.install, install);
 467         do_merge(&mut self.llvm, llvm);
 468         do_merge(&mut self.rust, rust);
 469         do_merge(&mut self.dist, dist);
 470         assert!(target.is_none(), "merging target-specific config is not currently supported");
 471     }
 472 }
 473
 474 // We are using a decl macro instead of a derive proc macro here to reduce the compile time of
 475 // rustbuild.
 476 macro_rules! define_config {
 477     ($(#[$attr:meta])* struct $name:ident {
 478         $($field:ident: Option<$field_ty:ty> = $field_key:literal,)*
 479     }) => {
 480         $(#[$attr])*
 481         struct $name {
 482             $($field: Option<$field_ty>,)*
 483         }
 484
 485         impl Merge for $name {
 486             fn merge(&mut self, other: Self) {
 487                 $(
 488                     if !self.$field.is_some() {
 489                         self.$field = other.$field;
 490                     }
 491                 )*
 492             }
 493         }
 494
 495         // The following is a trimmed version of what serde_derive generates. All parts not relevant
 496         // for toml deserialization have been removed. This reduces the binary size and improves
 497         // compile time of rustbuild.
 498         impl<'de> Deserialize<'de> for $name {
 499             fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
 500             where
 501                 D: Deserializer<'de>,
 502             {
 503                 struct Field;
 504                 impl<'de> serde::de::Visitor<'de> for Field {
 505                     type Value = $name;
 506                     fn expecting(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 507                         f.write_str(concat!("struct ", stringify!($name)))
 508                     }
 509
 510                     #[inline]
 511                     fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
 512                     where
 513                         A: serde::de::MapAccess<'de>,
 514                     {
 515                         $(let mut $field: Option<$field_ty> = None;)*
 516                         while let Some(key) =
 517                             match serde::de::MapAccess::next_key::<String>(&mut map) {
 518                                 Ok(val) => val,
 519                                 Err(err) => {
 520                                     return Err(err);
 521                                 }
 522                             }
 523                         {
 524                             match &*key {
 525                                 $($field_key => {
 526                                     if $field.is_some() {
 527                                         return Err(<A::Error as serde::de::Error>::duplicate_field(
 528                                             $field_key,
 529                                         ));
 530                                     }
 531                                     $field = match serde::de::MapAccess::next_value::<$field_ty>(
 532                                         &mut map,
 533                                     ) {
 534                                         Ok(val) => Some(val),
 535                                         Err(err) => {
 536                                             return Err(err);
 537                                         }
 538                                     };
 539                                 })*
 540                                 key => {
 541                                     return Err(serde::de::Error::unknown_field(key, FIELDS));
 542                                 }
 543                             }
 544                         }
 545                         Ok($name { $($field),* })
 546                     }
 547                 }
 548                 const FIELDS: &'static [&'static str] = &[
 549                     $($field_key,)*
 550                 ];
 551                 Deserializer::deserialize_struct(
 552                     deserializer,
 553                     stringify!($name),
 554                     FIELDS,
 555                     Field,
 556                 )
 557             }
 558         }
 559     }
 560 }
 561
 562 define_config! {
 563     /// TOML representation of various global build decisions.
 564     #[derive(Default)]
 565     struct Build {
 566         build: Option<String> = "build",
 567         host: Option<Vec<String>> = "host",
 568         target: Option<Vec<String>> = "target",
 569         build_dir: Option<String> = "build-dir",
 570         cargo: Option<String> = "cargo",
 571         rustc: Option<String> = "rustc",
 572         rustfmt: Option<PathBuf> = "rustfmt",
 573         docs: Option<bool> = "docs",
 574         compiler_docs: Option<bool> = "compiler-docs",
 575         docs_minification: Option<bool> = "docs-minification",
 576         submodules: Option<bool> = "submodules",
 577         gdb: Option<String> = "gdb",
 578         nodejs: Option<String> = "nodejs",
 579         npm: Option<String> = "npm",
 580         python: Option<String> = "python",
 581         locked_deps: Option<bool> = "locked-deps",
 582         vendor: Option<bool> = "vendor",
 583         full_bootstrap: Option<bool> = "full-bootstrap",
 584         extended: Option<bool> = "extended",
 585         tools: Option<HashSet<String>> = "tools",
 586         verbose: Option<usize> = "verbose",
 587         sanitizers: Option<bool> = "sanitizers",
 588         profiler: Option<bool> = "profiler",
 589         cargo_native_static: Option<bool> = "cargo-native-static",
 590         low_priority: Option<bool> = "low-priority",
 591         configure_args: Option<Vec<String>> = "configure-args",
 592         local_rebuild: Option<bool> = "local-rebuild",
 593         print_step_timings: Option<bool> = "print-step-timings",
 594         print_step_rusage: Option<bool> = "print-step-rusage",
 595         check_stage: Option<u32> = "check-stage",
 596         doc_stage: Option<u32> = "doc-stage",
 597         build_stage: Option<u32> = "build-stage",
 598         test_stage: Option<u32> = "test-stage",
 599         install_stage: Option<u32> = "install-stage",
 600         dist_stage: Option<u32> = "dist-stage",
 601         bench_stage: Option<u32> = "bench-stage",
 602         patch_binaries_for_nix: Option<bool> = "patch-binaries-for-nix",
 603         metrics: Option<bool> = "metrics",
 604         optimized_compiler_builtins: Option<bool> = "optimized-compiler-builtins",
 605     }
 606 }
 607
 608 define_config! {
 609     /// TOML representation of various global install decisions.
 610     struct Install {
 611         prefix: Option<String> = "prefix",
 612         sysconfdir: Option<String> = "sysconfdir",
 613         docdir: Option<String> = "docdir",
 614         bindir: Option<String> = "bindir",
 615         libdir: Option<String> = "libdir",
 616         mandir: Option<String> = "mandir",
 617         datadir: Option<String> = "datadir",
 618     }
 619 }
 620
 621 define_config! {
 622     /// TOML representation of how the LLVM build is configured.
 623     struct Llvm {
 624         skip_rebuild: Option<bool> = "skip-rebuild",
 625         optimize: Option<bool> = "optimize",
 626         thin_lto: Option<bool> = "thin-lto",
 627         release_debuginfo: Option<bool> = "release-debuginfo",
 628         assertions: Option<bool> = "assertions",
 629         tests: Option<bool> = "tests",
 630         plugins: Option<bool> = "plugins",
 631         ccache: Option<StringOrBool> = "ccache",
 632         version_check: Option<bool> = "version-check",
 633         static_libstdcpp: Option<bool> = "static-libstdcpp",
 634         ninja: Option<bool> = "ninja",
 635         targets: Option<String> = "targets",
 636         experimental_targets: Option<String> = "experimental-targets",
 637         link_jobs: Option<u32> = "link-jobs",
 638         link_shared: Option<bool> = "link-shared",
 639         version_suffix: Option<String> = "version-suffix",
 640         clang_cl: Option<String> = "clang-cl",
 641         cflags: Option<String> = "cflags",
 642         cxxflags: Option<String> = "cxxflags",
 643         ldflags: Option<String> = "ldflags",
 644         use_libcxx: Option<bool> = "use-libcxx",
 645         use_linker: Option<String> = "use-linker",
 646         allow_old_toolchain: Option<bool> = "allow-old-toolchain",
 647         polly: Option<bool> = "polly",
 648         clang: Option<bool> = "clang",
 649         download_ci_llvm: Option<StringOrBool> = "download-ci-llvm",
 650         build_config: Option<HashMap<String, String>> = "build-config",
 651     }
 652 }
 653
 654 define_config! {
 655     struct Dist {
 656         sign_folder: Option<String> = "sign-folder",
 657         gpg_password_file: Option<String> = "gpg-password-file",
 658         upload_addr: Option<String> = "upload-addr",
 659         src_tarball: Option<bool> = "src-tarball",
 660         missing_tools: Option<bool> = "missing-tools",
 661         compression_formats: Option<Vec<String>> = "compression-formats",
 662     }
 663 }
 664
 665 #[derive(Deserialize)]
 666 #[serde(untagged)]
 667 enum StringOrBool {
 668     String(String),
 669     Bool(bool),
 670 }
 671
 672 impl Default for StringOrBool {
 673     fn default() -> StringOrBool {
 674         StringOrBool::Bool(false)
 675     }
 676 }
 677
 678 define_config! {
 679     /// TOML representation of how the Rust build is configured.
 680     struct Rust {
 681         optimize: Option<bool> = "optimize",
 682         debug: Option<bool> = "debug",
 683         codegen_units: Option<u32> = "codegen-units",
 684         codegen_units_std: Option<u32> = "codegen-units-std",
 685         debug_assertions: Option<bool> = "debug-assertions",
 686         debug_assertions_std: Option<bool> = "debug-assertions-std",
 687         overflow_checks: Option<bool> = "overflow-checks",
 688         overflow_checks_std: Option<bool> = "overflow-checks-std",
 689         debug_logging: Option<bool> = "debug-logging",
 690         debuginfo_level: Option<u32> = "debuginfo-level",
 691         debuginfo_level_rustc: Option<u32> = "debuginfo-level-rustc",
 692         debuginfo_level_std: Option<u32> = "debuginfo-level-std",
 693         debuginfo_level_tools: Option<u32> = "debuginfo-level-tools",
 694         debuginfo_level_tests: Option<u32> = "debuginfo-level-tests",
 695         split_debuginfo: Option<String> = "split-debuginfo",
 696         run_dsymutil: Option<bool> = "run-dsymutil",
 697         backtrace: Option<bool> = "backtrace",
 698         incremental: Option<bool> = "incremental",
 699         parallel_compiler: Option<bool> = "parallel-compiler",
 700         default_linker: Option<String> = "default-linker",
 701         channel: Option<String> = "channel",
 702         description: Option<String> = "description",
 703         musl_root: Option<String> = "musl-root",
 704         rpath: Option<bool> = "rpath",
 705         verbose_tests: Option<bool> = "verbose-tests",
 706         optimize_tests: Option<bool> = "optimize-tests",
 707         codegen_tests: Option<bool> = "codegen-tests",
 708         ignore_git: Option<bool> = "ignore-git",
 709         dist_src: Option<bool> = "dist-src",
 710         save_toolstates: Option<String> = "save-toolstates",
 711         codegen_backends: Option<Vec<String>> = "codegen-backends",
 712         lld: Option<bool> = "lld",
 713         use_lld: Option<bool> = "use-lld",
 714         llvm_tools: Option<bool> = "llvm-tools",
 715         deny_warnings: Option<bool> = "deny-warnings",
 716         backtrace_on_ice: Option<bool> = "backtrace-on-ice",
 717         verify_llvm_ir: Option<bool> = "verify-llvm-ir",
 718         thin_lto_import_instr_limit: Option<u32> = "thin-lto-import-instr-limit",
 719         remap_debuginfo: Option<bool> = "remap-debuginfo",
 720         jemalloc: Option<bool> = "jemalloc",
 721         test_compare_mode: Option<bool> = "test-compare-mode",
 722         llvm_libunwind: Option<String> = "llvm-libunwind",
 723         control_flow_guard: Option<bool> = "control-flow-guard",
 724         new_symbol_mangling: Option<bool> = "new-symbol-mangling",
 725         profile_generate: Option<String> = "profile-generate",
 726         profile_use: Option<String> = "profile-use",
 727         // ignored; this is set from an env var set by bootstrap.py
 728         download_rustc: Option<StringOrBool> = "download-rustc",
 729     }
 730 }
 731
 732 define_config! {
 733     /// TOML representation of how each build target is configured.
 734     struct TomlTarget {
 735         cc: Option<String> = "cc",
 736         cxx: Option<String> = "cxx",
 737         ar: Option<String> = "ar",
 738         ranlib: Option<String> = "ranlib",
 739         default_linker: Option<PathBuf> = "default-linker",
 740         linker: Option<String> = "linker",
 741         llvm_config: Option<String> = "llvm-config",
 742         llvm_has_rust_patches: Option<bool> = "llvm-has-rust-patches",
 743         llvm_filecheck: Option<String> = "llvm-filecheck",
 744         llvm_libunwind: Option<String> = "llvm-libunwind",
 745         android_ndk: Option<String> = "android-ndk",
 746         sanitizers: Option<bool> = "sanitizers",
 747         profiler: Option<bool> = "profiler",
 748         crt_static: Option<bool> = "crt-static",
 749         musl_root: Option<String> = "musl-root",
 750         musl_libdir: Option<String> = "musl-libdir",
 751         wasi_root: Option<String> = "wasi-root",
 752         qemu_rootfs: Option<String> = "qemu-rootfs",
 753         no_std: Option<bool> = "no-std",
 754     }
 755 }
 756
 757 impl Config {
 758     pub fn default_opts() -> Config {
 759         let mut config = Config::default();
 760         config.llvm_optimize = true;
 761         config.ninja_in_file = true;
 762         config.llvm_version_check = true;
 763         config.llvm_static_stdcpp = true;
 764         config.backtrace = true;
 765         config.rust_optimize = true;
 766         config.rust_optimize_tests = true;
 767         config.submodules = None;
 768         config.docs = true;
 769         config.docs_minification = true;
 770         config.rust_rpath = true;
 771         config.channel = "dev".to_string();
 772         config.codegen_tests = true;
 773         config.rust_dist_src = true;
 774         config.rust_codegen_backends = vec![INTERNER.intern_str("llvm")];
 775         config.deny_warnings = true;
 776         config.bindir = "bin".into();
 777
 778         // set by build.rs
 779         config.build = TargetSelection::from_user(&env!("BUILD_TRIPLE"));
 780
 781         let manifest_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
 782         // Undo `src/bootstrap`
 783         config.src = manifest_dir.parent().unwrap().parent().unwrap().to_owned();
 784         config.out = PathBuf::from("build");
 785
 786         config
 787     }
 788
 789     pub fn parse(args: &[String]) -> Config {
 790         let flags = Flags::parse(&args);
 791         let mut config = Config::default_opts();
 792
 793         // Set flags.
 794         config.exclude = flags.exclude.into_iter().map(|path| TaskPath::parse(path)).collect();
 795         config.include_default_paths = flags.include_default_paths;
 796         config.rustc_error_format = flags.rustc_error_format;
 797         config.json_output = flags.json_output;
 798         config.on_fail = flags.on_fail;
 799         config.jobs = flags.jobs.map(threads_from_config);
 800         config.cmd = flags.cmd;
 801         config.incremental = flags.incremental;
 802         config.dry_run = flags.dry_run;
 803         config.keep_stage = flags.keep_stage;
 804         config.keep_stage_std = flags.keep_stage_std;
 805         config.color = flags.color;
 806         if let Some(value) = flags.deny_warnings {
 807             config.deny_warnings = value;
 808         }
 809         config.llvm_profile_use = flags.llvm_profile_use;
 810         config.llvm_profile_generate = flags.llvm_profile_generate;
 811         config.llvm_bolt_profile_generate = flags.llvm_bolt_profile_generate;
 812         config.llvm_bolt_profile_use = flags.llvm_bolt_profile_use;
 813
 814         if config.llvm_bolt_profile_generate && config.llvm_bolt_profile_use.is_some() {
 815             eprintln!(
 816                 "Cannot use both `llvm_bolt_profile_generate` and `llvm_bolt_profile_use` at the same time"
 817             );
 818             crate::detail_exit(1);
 819         }
 820
 821         // Infer the rest of the configuration.
 822
 823         // Infer the source directory. This is non-trivial because we want to support a downloaded bootstrap binary,
 824         // running on a completely machine from where it was compiled.
 825         let mut cmd = Command::new("git");
 826         // NOTE: we cannot support running from outside the repository because the only path we have available
 827         // is set at compile time, which can be wrong if bootstrap was downloaded from source.
 828         // We still support running outside the repository if we find we aren't in a git directory.
 829         cmd.arg("rev-parse").arg("--show-toplevel");
 830         // Discard stderr because we expect this to fail when building from a tarball.
 831         let output = cmd
 832             .stderr(std::process::Stdio::null())
 833             .output()
 834             .ok()
 835             .and_then(|output| if output.status.success() { Some(output) } else { None });
 836         if let Some(output) = output {
 837             let git_root = String::from_utf8(output.stdout).unwrap();
 838             // We need to canonicalize this path to make sure it uses backslashes instead of forward slashes.
 839             let git_root = PathBuf::from(git_root.trim()).canonicalize().unwrap();
 840             let s = git_root.to_str().unwrap();
 841
 842             // Bootstrap is quite bad at handling /? in front of paths
 843             let src = match s.strip_prefix("\\\\?\\") {
 844                 Some(p) => PathBuf::from(p),
 845                 None => PathBuf::from(git_root),
 846             };
 847             // If this doesn't have at least `stage0.json`, we guessed wrong. This can happen when,
 848             // for example, the build directory is inside of another unrelated git directory.
 849             // In that case keep the original `CARGO_MANIFEST_DIR` handling.
 850             //
 851             // NOTE: this implies that downloadable bootstrap isn't supported when the build directory is outside
 852             // the source directory. We could fix that by setting a variable from all three of python, ./x, and x.ps1.
 853             if src.join("src").join("stage0.json").exists() {
 854                 config.src = src;
 855             }
 856         } else {
 857             // We're building from a tarball, not git sources.
 858             // We don't support pre-downloaded bootstrap in this case.
 859         }
 860
 861         if cfg!(test) {
 862             // Use the build directory of the original x.py invocation, so that we can set `initial_rustc` properly.
 863             config.out = Path::new(
 864                 &env::var_os("CARGO_TARGET_DIR").expect("cargo test directly is not supported"),
 865             )
 866             .parent()
 867             .unwrap()
 868             .to_path_buf();
 869         }
 870
 871         let stage0_json = t!(std::fs::read(&config.src.join("src").join("stage0.json")));
 872
 873         config.stage0_metadata = t!(serde_json::from_slice::<Stage0Metadata>(&stage0_json));
 874
 875         #[cfg(test)]
 876         let get_toml = |_| TomlConfig::default();
 877         #[cfg(not(test))]
 878         let get_toml = |file: &Path| {
 879             let contents =
 880                 t!(fs::read_to_string(file), format!("config file {} not found", file.display()));
 881             // Deserialize to Value and then TomlConfig to prevent the Deserialize impl of
 882             // TomlConfig and sub types to be monomorphized 5x by toml.
 883             match toml::from_str(&contents)
 884                 .and_then(|table: toml::Value| TomlConfig::deserialize(table))
 885             {
 886                 Ok(table) => table,
 887                 Err(err) => {
 888                     eprintln!("failed to parse TOML configuration '{}': {}", file.display(), err);
 889                     crate::detail_exit(2);
 890                 }
 891             }
 892         };
 893
 894         // Read from `--config`, then `RUST_BOOTSTRAP_CONFIG`, then `./config.toml`, then `config.toml` in the root directory.
 895         let toml_path = flags
 896             .config
 897             .clone()
 898             .or_else(|| env::var_os("RUST_BOOTSTRAP_CONFIG").map(PathBuf::from));
 899         let using_default_path = toml_path.is_none();
 900         let mut toml_path = toml_path.unwrap_or_else(|| PathBuf::from("config.toml"));
 901         if using_default_path && !toml_path.exists() {
 902             toml_path = config.src.join(toml_path);
 903         }
 904
 905         // Give a hard error if `--config` or `RUST_BOOTSTRAP_CONFIG` are set to a missing path,
 906         // but not if `config.toml` hasn't been created.
 907         let mut toml = if !using_default_path || toml_path.exists() {
 908             get_toml(&toml_path)
 909         } else {
 910             TomlConfig::default()
 911         };
 912
 913         if let Some(include) = &toml.profile {
 914             let mut include_path = config.src.clone();
 915             include_path.push("src");
 916             include_path.push("bootstrap");
 917             include_path.push("defaults");
 918             include_path.push(format!("config.{}.toml", include));
 919             let included_toml = get_toml(&include_path);
 920             toml.merge(included_toml);
 921         }
 922
 923         config.changelog_seen = toml.changelog_seen;
 924         config.config = toml_path;
 925
 926         let build = toml.build.unwrap_or_default();
 927
 928         set(&mut config.out, flags.build_dir.or_else(|| build.build_dir.map(PathBuf::from)));
 929         // NOTE: Bootstrap spawns various commands with different working directories.
 930         // To avoid writing to random places on the file system, `config.out` needs to be an absolute path.
 931         if !config.out.is_absolute() {
 932             // `canonicalize` requires the path to already exist. Use our vendored copy of `absolute` instead.
 933             config.out = crate::util::absolute(&config.out);
 934         }
 935
 936         config.initial_rustc = build
 937             .rustc
 938             .map(PathBuf::from)
 939             .unwrap_or_else(|| config.out.join(config.build.triple).join("stage0/bin/rustc"));
 940         config.initial_cargo = build
 941             .cargo
 942             .map(PathBuf::from)
 943             .unwrap_or_else(|| config.out.join(config.build.triple).join("stage0/bin/cargo"));
 944
 945         // NOTE: it's important this comes *after* we set `initial_rustc` just above.
 946         if config.dry_run {
 947             let dir = config.out.join("tmp-dry-run");
 948             t!(fs::create_dir_all(&dir));
 949             config.out = dir;
 950         }
 951
 952         config.hosts = if let Some(arg_host) = flags.host {
 953             arg_host
 954         } else if let Some(file_host) = build.host {
 955             file_host.iter().map(|h| TargetSelection::from_user(h)).collect()
 956         } else {
 957             vec![config.build]
 958         };
 959         config.targets = if let Some(arg_target) = flags.target {
 960             arg_target
 961         } else if let Some(file_target) = build.target {
 962             file_target.iter().map(|h| TargetSelection::from_user(h)).collect()
 963         } else {
 964             // If target is *not* configured, then default to the host
 965             // toolchains.
 966             config.hosts.clone()
 967         };
 968
 969         config.nodejs = build.nodejs.map(PathBuf::from);
 970         config.npm = build.npm.map(PathBuf::from);
 971         config.gdb = build.gdb.map(PathBuf::from);
 972         config.python = build.python.map(PathBuf::from);
 973         config.submodules = build.submodules;
 974         set(&mut config.low_priority, build.low_priority);
 975         set(&mut config.compiler_docs, build.compiler_docs);
 976         set(&mut config.docs_minification, build.docs_minification);
 977         set(&mut config.docs, build.docs);
 978         set(&mut config.locked_deps, build.locked_deps);
 979         set(&mut config.vendor, build.vendor);
 980         set(&mut config.full_bootstrap, build.full_bootstrap);
 981         set(&mut config.extended, build.extended);
 982         config.tools = build.tools;
 983         set(&mut config.verbose, build.verbose);
 984         set(&mut config.sanitizers, build.sanitizers);
 985         set(&mut config.profiler, build.profiler);
 986         set(&mut config.cargo_native_static, build.cargo_native_static);
 987         set(&mut config.configure_args, build.configure_args);
 988         set(&mut config.local_rebuild, build.local_rebuild);
 989         set(&mut config.print_step_timings, build.print_step_timings);
 990         set(&mut config.print_step_rusage, build.print_step_rusage);
 991         set(&mut config.patch_binaries_for_nix, build.patch_binaries_for_nix);
 992         set(&mut config.optimized_compiler_builtins, build.optimized_compiler_builtins);
 993
 994         config.verbose = cmp::max(config.verbose, flags.verbose);
 995
 996         if let Some(install) = toml.install {
 997             config.prefix = install.prefix.map(PathBuf::from);
 998             config.sysconfdir = install.sysconfdir.map(PathBuf::from);
 999             config.datadir = install.datadir.map(PathBuf::from);
1000             config.docdir = install.docdir.map(PathBuf::from);
1001             set(&mut config.bindir, install.bindir.map(PathBuf::from));
1002             config.libdir = install.libdir.map(PathBuf::from);
1003             config.mandir = install.mandir.map(PathBuf::from);
1004         }
1005
1006         // We want the llvm-skip-rebuild flag to take precedence over the
1007         // skip-rebuild config.toml option so we store it separately
1008         // so that we can infer the right value
1009         let mut llvm_skip_rebuild = flags.llvm_skip_rebuild;
1010
1011         // Store off these values as options because if they're not provided
1012         // we'll infer default values for them later
1013         let mut llvm_assertions = None;
1014         let mut llvm_tests = None;
1015         let mut llvm_plugins = None;
1016         let mut debug = None;
1017         let mut debug_assertions = None;
1018         let mut debug_assertions_std = None;
1019         let mut overflow_checks = None;
1020         let mut overflow_checks_std = None;
1021         let mut debug_logging = None;
1022         let mut debuginfo_level = None;
1023         let mut debuginfo_level_rustc = None;
1024         let mut debuginfo_level_std = None;
1025         let mut debuginfo_level_tools = None;
1026         let mut debuginfo_level_tests = None;
1027         let mut optimize = None;
1028         let mut ignore_git = None;
1029
1030         if let Some(llvm) = toml.llvm {
1031             match llvm.ccache {
1032                 Some(StringOrBool::String(ref s)) => config.ccache = Some(s.to_string()),
1033                 Some(StringOrBool::Bool(true)) => {
1034                     config.ccache = Some("ccache".to_string());
1035                 }
1036                 Some(StringOrBool::Bool(false)) | None => {}
1037             }
1038             set(&mut config.ninja_in_file, llvm.ninja);
1039             llvm_assertions = llvm.assertions;
1040             llvm_tests = llvm.tests;
1041             llvm_plugins = llvm.plugins;
1042             llvm_skip_rebuild = llvm_skip_rebuild.or(llvm.skip_rebuild);
1043             set(&mut config.llvm_optimize, llvm.optimize);
1044             set(&mut config.llvm_thin_lto, llvm.thin_lto);
1045             set(&mut config.llvm_release_debuginfo, llvm.release_debuginfo);
1046             set(&mut config.llvm_version_check, llvm.version_check);
1047             set(&mut config.llvm_static_stdcpp, llvm.static_libstdcpp);
1048             if let Some(v) = llvm.link_shared {
1049                 config.llvm_link_shared.set(Some(v));
1050             }
1051             config.llvm_targets = llvm.targets.clone();
1052             config.llvm_experimental_targets = llvm.experimental_targets.clone();
1053             config.llvm_link_jobs = llvm.link_jobs;
1054             config.llvm_version_suffix = llvm.version_suffix.clone();
1055             config.llvm_clang_cl = llvm.clang_cl.clone();
1056
1057             config.llvm_cflags = llvm.cflags.clone();
1058             config.llvm_cxxflags = llvm.cxxflags.clone();
1059             config.llvm_ldflags = llvm.ldflags.clone();
1060             set(&mut config.llvm_use_libcxx, llvm.use_libcxx);
1061             config.llvm_use_linker = llvm.use_linker.clone();
1062             config.llvm_allow_old_toolchain = llvm.allow_old_toolchain.unwrap_or(false);
1063             config.llvm_polly = llvm.polly.unwrap_or(false);
1064             config.llvm_clang = llvm.clang.unwrap_or(false);
1065             config.llvm_build_config = llvm.build_config.clone().unwrap_or(Default::default());
1066             config.llvm_from_ci = match llvm.download_ci_llvm {
1067                 Some(StringOrBool::String(s)) => {
1068                     assert!(s == "if-available", "unknown option `{}` for download-ci-llvm", s);
1069                     crate::native::is_ci_llvm_available(&config, llvm_assertions.unwrap_or(false))
1070                 }
1071                 Some(StringOrBool::Bool(b)) => b,
1072                 None => false,
1073             };
1074
1075             if config.llvm_from_ci {
1076                 // None of the LLVM options, except assertions, are supported
1077                 // when using downloaded LLVM. We could just ignore these but
1078                 // that's potentially confusing, so force them to not be
1079                 // explicitly set. The defaults and CI defaults don't
1080                 // necessarily match but forcing people to match (somewhat
1081                 // arbitrary) CI configuration locally seems bad/hard.
1082                 check_ci_llvm!(llvm.optimize);
1083                 check_ci_llvm!(llvm.thin_lto);
1084                 check_ci_llvm!(llvm.release_debuginfo);
1085                 // CI-built LLVM can be either dynamic or static. We won't know until we download it.
1086                 check_ci_llvm!(llvm.link_shared);
1087                 check_ci_llvm!(llvm.static_libstdcpp);
1088                 check_ci_llvm!(llvm.targets);
1089                 check_ci_llvm!(llvm.experimental_targets);
1090                 check_ci_llvm!(llvm.link_jobs);
1091                 check_ci_llvm!(llvm.clang_cl);
1092                 check_ci_llvm!(llvm.version_suffix);
1093                 check_ci_llvm!(llvm.cflags);
1094                 check_ci_llvm!(llvm.cxxflags);
1095                 check_ci_llvm!(llvm.ldflags);
1096                 check_ci_llvm!(llvm.use_libcxx);
1097                 check_ci_llvm!(llvm.use_linker);
1098                 check_ci_llvm!(llvm.allow_old_toolchain);
1099                 check_ci_llvm!(llvm.polly);
1100                 check_ci_llvm!(llvm.clang);
1101                 check_ci_llvm!(llvm.build_config);
1102                 check_ci_llvm!(llvm.plugins);
1103             }
1104
1105             // NOTE: can never be hit when downloading from CI, since we call `check_ci_llvm!(thin_lto)` above.
1106             if config.llvm_thin_lto && llvm.link_shared.is_none() {
1107                 // If we're building with ThinLTO on, by default we want to link
1108                 // to LLVM shared, to avoid re-doing ThinLTO (which happens in
1109                 // the link step) with each stage.
1110                 config.llvm_link_shared.set(Some(true));
1111             }
1112         }
1113
1114         if let Some(rust) = toml.rust {
1115             debug = rust.debug;
1116             debug_assertions = rust.debug_assertions;
1117             debug_assertions_std = rust.debug_assertions_std;
1118             overflow_checks = rust.overflow_checks;
1119             overflow_checks_std = rust.overflow_checks_std;
1120             debug_logging = rust.debug_logging;
1121             debuginfo_level = rust.debuginfo_level;
1122             debuginfo_level_rustc = rust.debuginfo_level_rustc;
1123             debuginfo_level_std = rust.debuginfo_level_std;
1124             debuginfo_level_tools = rust.debuginfo_level_tools;
1125             debuginfo_level_tests = rust.debuginfo_level_tests;
1126             config.rust_split_debuginfo = rust
1127                 .split_debuginfo
1128                 .as_deref()
1129                 .map(SplitDebuginfo::from_str)
1130                 .map(|v| v.expect("invalid value for rust.split_debuginfo"))
1131                 .unwrap_or(SplitDebuginfo::default_for_platform(&config.build.triple));
1132             optimize = rust.optimize;
1133             ignore_git = rust.ignore_git;
1134             config.rust_new_symbol_mangling = rust.new_symbol_mangling;
1135             set(&mut config.rust_optimize_tests, rust.optimize_tests);
1136             set(&mut config.codegen_tests, rust.codegen_tests);
1137             set(&mut config.rust_rpath, rust.rpath);
1138             set(&mut config.jemalloc, rust.jemalloc);
1139             set(&mut config.test_compare_mode, rust.test_compare_mode);
1140             set(&mut config.backtrace, rust.backtrace);
1141             set(&mut config.channel, rust.channel);
1142             config.description = rust.description;
1143             set(&mut config.rust_dist_src, rust.dist_src);
1144             set(&mut config.verbose_tests, rust.verbose_tests);
1145             // in the case "false" is set explicitly, do not overwrite the command line args
1146             if let Some(true) = rust.incremental {
1147                 config.incremental = true;
1148             }
1149             set(&mut config.use_lld, rust.use_lld);
1150             set(&mut config.lld_enabled, rust.lld);
1151             set(&mut config.llvm_tools_enabled, rust.llvm_tools);
1152             config.rustc_parallel = rust.parallel_compiler.unwrap_or(false);
1153             config.rustc_default_linker = rust.default_linker;
1154             config.musl_root = rust.musl_root.map(PathBuf::from);
1155             config.save_toolstates = rust.save_toolstates.map(PathBuf::from);
1156             set(&mut config.deny_warnings, flags.deny_warnings.or(rust.deny_warnings));
1157             set(&mut config.backtrace_on_ice, rust.backtrace_on_ice);
1158             set(&mut config.rust_verify_llvm_ir, rust.verify_llvm_ir);
1159             config.rust_thin_lto_import_instr_limit = rust.thin_lto_import_instr_limit;
1160             set(&mut config.rust_remap_debuginfo, rust.remap_debuginfo);
1161             set(&mut config.control_flow_guard, rust.control_flow_guard);
1162             config.llvm_libunwind_default = rust
1163                 .llvm_libunwind
1164                 .map(|v| v.parse().expect("failed to parse rust.llvm-libunwind"));
1165
1166             if let Some(ref backends) = rust.codegen_backends {
1167                 config.rust_codegen_backends =
1168                     backends.iter().map(|s| INTERNER.intern_str(s)).collect();
1169             }
1170
1171             config.rust_codegen_units = rust.codegen_units.map(threads_from_config);
1172             config.rust_codegen_units_std = rust.codegen_units_std.map(threads_from_config);
1173             config.rust_profile_use = flags.rust_profile_use.or(rust.profile_use);
1174             config.rust_profile_generate = flags.rust_profile_generate.or(rust.profile_generate);
1175             config.download_rustc_commit = download_ci_rustc_commit(&config, rust.download_rustc);
1176         } else {
1177             config.rust_profile_use = flags.rust_profile_use;
1178             config.rust_profile_generate = flags.rust_profile_generate;
1179         }
1180
1181         if let Some(t) = toml.target {
1182             for (triple, cfg) in t {
1183                 let mut target = Target::from_triple(&triple);
1184
1185                 if let Some(ref s) = cfg.llvm_config {
1186                     target.llvm_config = Some(config.src.join(s));
1187                 }
1188                 target.llvm_has_rust_patches = cfg.llvm_has_rust_patches;
1189                 if let Some(ref s) = cfg.llvm_filecheck {
1190                     target.llvm_filecheck = Some(config.src.join(s));
1191                 }
1192                 target.llvm_libunwind = cfg
1193                     .llvm_libunwind
1194                     .as_ref()
1195                     .map(|v| v.parse().expect("failed to parse rust.llvm-libunwind"));
1196                 if let Some(ref s) = cfg.android_ndk {
1197                     target.ndk = Some(config.src.join(s));
1198                 }
1199                 if let Some(s) = cfg.no_std {
1200                     target.no_std = s;
1201                 }
1202                 target.cc = cfg.cc.map(PathBuf::from);
1203                 target.cxx = cfg.cxx.map(PathBuf::from);
1204                 target.ar = cfg.ar.map(PathBuf::from);
1205                 target.ranlib = cfg.ranlib.map(PathBuf::from);
1206                 target.linker = cfg.linker.map(PathBuf::from);
1207                 target.crt_static = cfg.crt_static;
1208                 target.musl_root = cfg.musl_root.map(PathBuf::from);
1209                 target.musl_libdir = cfg.musl_libdir.map(PathBuf::from);
1210                 target.wasi_root = cfg.wasi_root.map(PathBuf::from);
1211                 target.qemu_rootfs = cfg.qemu_rootfs.map(PathBuf::from);
1212                 target.sanitizers = cfg.sanitizers;
1213                 target.profiler = cfg.profiler;
1214
1215                 config.target_config.insert(TargetSelection::from_user(&triple), target);
1216             }
1217         }
1218
1219         if config.llvm_from_ci {
1220             let triple = &config.build.triple;
1221             let ci_llvm_bin = config.ci_llvm_root().join("bin");
1222             let mut build_target = config
1223                 .target_config
1224                 .entry(config.build)
1225                 .or_insert_with(|| Target::from_triple(&triple));
1226
1227             check_ci_llvm!(build_target.llvm_config);
1228             check_ci_llvm!(build_target.llvm_filecheck);
1229             build_target.llvm_config = Some(ci_llvm_bin.join(exe("llvm-config", config.build)));
1230             build_target.llvm_filecheck = Some(ci_llvm_bin.join(exe("FileCheck", config.build)));
1231         }
1232
1233         if let Some(t) = toml.dist {
1234             config.dist_sign_folder = t.sign_folder.map(PathBuf::from);
1235             config.dist_upload_addr = t.upload_addr;
1236             config.dist_compression_formats = t.compression_formats;
1237             set(&mut config.rust_dist_src, t.src_tarball);
1238             set(&mut config.missing_tools, t.missing_tools);
1239         }
1240
1241         if let Some(r) = build.rustfmt {
1242             *config.initial_rustfmt.borrow_mut() = if r.exists() {
1243                 RustfmtState::SystemToolchain(r)
1244             } else {
1245                 RustfmtState::Unavailable
1246             };
1247         } else {
1248             // If using a system toolchain for bootstrapping, see if that has rustfmt available.
1249             let host = config.build;
1250             let rustfmt_path = config.initial_rustc.with_file_name(exe("rustfmt", host));
1251             let bin_root = config.out.join(host.triple).join("stage0");
1252             if !rustfmt_path.starts_with(&bin_root) {
1253                 // Using a system-provided toolchain; we shouldn't download rustfmt.
1254                 *config.initial_rustfmt.borrow_mut() = RustfmtState::SystemToolchain(rustfmt_path);
1255             }
1256         }
1257
1258         // Now that we've reached the end of our configuration, infer the
1259         // default values for all options that we haven't otherwise stored yet.
1260
1261         config.llvm_skip_rebuild = llvm_skip_rebuild.unwrap_or(false);
1262         config.llvm_assertions = llvm_assertions.unwrap_or(false);
1263         config.llvm_tests = llvm_tests.unwrap_or(false);
1264         config.llvm_plugins = llvm_plugins.unwrap_or(false);
1265         config.rust_optimize = optimize.unwrap_or(true);
1266
1267         let default = debug == Some(true);
1268         config.rust_debug_assertions = debug_assertions.unwrap_or(default);
1269         config.rust_debug_assertions_std =
1270             debug_assertions_std.unwrap_or(config.rust_debug_assertions);
1271         config.rust_overflow_checks = overflow_checks.unwrap_or(default);
1272         config.rust_overflow_checks_std =
1273             overflow_checks_std.unwrap_or(config.rust_overflow_checks);
1274
1275         config.rust_debug_logging = debug_logging.unwrap_or(config.rust_debug_assertions);
1276
1277         let with_defaults = |debuginfo_level_specific: Option<u32>| {
1278             debuginfo_level_specific.or(debuginfo_level).unwrap_or(if debug == Some(true) {
1279                 1
1280             } else {
1281                 0
1282             })
1283         };
1284         config.rust_debuginfo_level_rustc = with_defaults(debuginfo_level_rustc);
1285         config.rust_debuginfo_level_std = with_defaults(debuginfo_level_std);
1286         config.rust_debuginfo_level_tools = with_defaults(debuginfo_level_tools);
1287         config.rust_debuginfo_level_tests = debuginfo_level_tests.unwrap_or(0);
1288
1289         let default = config.channel == "dev";
1290         config.ignore_git = ignore_git.unwrap_or(default);
1291
1292         let download_rustc = config.download_rustc_commit.is_some();
1293         // See https://github.com/rust-lang/compiler-team/issues/326
1294         config.stage = match config.cmd {
1295             Subcommand::Check { .. } => flags.stage.or(build.check_stage).unwrap_or(0),
1296             // `download-rustc` only has a speed-up for stage2 builds. Default to stage2 unless explicitly overridden.
1297             Subcommand::Doc { .. } => {
1298                 flags.stage.or(build.doc_stage).unwrap_or(if download_rustc { 2 } else { 0 })
1299             }
1300             Subcommand::Build { .. } => {
1301                 flags.stage.or(build.build_stage).unwrap_or(if download_rustc { 2 } else { 1 })
1302             }
1303             Subcommand::Test { .. } => {
1304                 flags.stage.or(build.test_stage).unwrap_or(if download_rustc { 2 } else { 1 })
1305             }
1306             Subcommand::Bench { .. } => flags.stage.or(build.bench_stage).unwrap_or(2),
1307             Subcommand::Dist { .. } => flags.stage.or(build.dist_stage).unwrap_or(2),
1308             Subcommand::Install { .. } => flags.stage.or(build.install_stage).unwrap_or(2),
1309             // These are all bootstrap tools, which don't depend on the compiler.
1310             // The stage we pass shouldn't matter, but use 0 just in case.
1311             Subcommand::Clean { .. }
1312             | Subcommand::Clippy { .. }
1313             | Subcommand::Fix { .. }
1314             | Subcommand::Run { .. }
1315             | Subcommand::Setup { .. }
1316             | Subcommand::Format { .. } => flags.stage.unwrap_or(0),
1317         };
1318
1319         // CI should always run stage 2 builds, unless it specifically states otherwise
1320         #[cfg(not(test))]
1321         if flags.stage.is_none() && crate::CiEnv::current() != crate::CiEnv::None {
1322             match config.cmd {
1323                 Subcommand::Test { .. }
1324                 | Subcommand::Doc { .. }
1325                 | Subcommand::Build { .. }
1326                 | Subcommand::Bench { .. }
1327                 | Subcommand::Dist { .. }
1328                 | Subcommand::Install { .. } => {
1329                     assert_eq!(
1330                         config.stage, 2,
1331                         "x.py should be run with `--stage 2` on CI, but was run with `--stage {}`",
1332                         config.stage,
1333                     );
1334                 }
1335                 Subcommand::Clean { .. }
1336                 | Subcommand::Check { .. }
1337                 | Subcommand::Clippy { .. }
1338                 | Subcommand::Fix { .. }
1339                 | Subcommand::Run { .. }
1340                 | Subcommand::Setup { .. }
1341                 | Subcommand::Format { .. } => {}
1342             }
1343         }
1344
1345         config
1346     }
1347
1348     /// A git invocation which runs inside the source directory.
1349     ///
1350     /// Use this rather than `Command::new("git")` in order to support out-of-tree builds.
1351     pub(crate) fn git(&self) -> Command {
1352         let mut git = Command::new("git");
1353         git.current_dir(&self.src);
1354         git
1355     }
1356
1357     pub(crate) fn artifact_channel(&self, builder: &Builder<'_>, commit: &str) -> String {
1358         if builder.rust_info.is_managed_git_subrepository() {
1359             let mut channel = self.git();
1360             channel.arg("show").arg(format!("{}:src/ci/channel", commit));
1361             let channel = output(&mut channel);
1362             channel.trim().to_owned()
1363         } else if let Ok(channel) = fs::read_to_string(builder.src.join("src/ci/channel")) {
1364             channel.trim().to_owned()
1365         } else {
1366             let src = builder.src.display();
1367             eprintln!("error: failed to determine artifact channel");
1368             eprintln!(
1369                 "help: either use git or ensure that {src}/src/ci/channel contains the name of the channel to use"
1370             );
1371             panic!();
1372         }
1373     }
1374
1375     /// Try to find the relative path of `bindir`, otherwise return it in full.
1376     pub fn bindir_relative(&self) -> &Path {
1377         let bindir = &self.bindir;
1378         if bindir.is_absolute() {
1379             // Try to make it relative to the prefix.
1380             if let Some(prefix) = &self.prefix {
1381                 if let Ok(stripped) = bindir.strip_prefix(prefix) {
1382                     return stripped;
1383                 }
1384             }
1385         }
1386         bindir
1387     }
1388
1389     /// Try to find the relative path of `libdir`.
1390     pub fn libdir_relative(&self) -> Option<&Path> {
1391         let libdir = self.libdir.as_ref()?;
1392         if libdir.is_relative() {
1393             Some(libdir)
1394         } else {
1395             // Try to make it relative to the prefix.
1396             libdir.strip_prefix(self.prefix.as_ref()?).ok()
1397         }
1398     }
1399
1400     /// The absolute path to the downloaded LLVM artifacts.
1401     pub(crate) fn ci_llvm_root(&self) -> PathBuf {
1402         assert!(self.llvm_from_ci);
1403         self.out.join(&*self.build.triple).join("ci-llvm")
1404     }
1405
1406     /// Determine whether llvm should be linked dynamically.
1407     ///
1408     /// If `false`, llvm should be linked statically.
1409     /// This is computed on demand since LLVM might have to first be downloaded from CI.
1410     pub(crate) fn llvm_link_shared(builder: &Builder<'_>) -> bool {
1411         let mut opt = builder.config.llvm_link_shared.get();
1412         if opt.is_none() && builder.config.dry_run {
1413             // just assume static for now - dynamic linking isn't supported on all platforms
1414             return false;
1415         }
1416
1417         let llvm_link_shared = *opt.get_or_insert_with(|| {
1418             if builder.config.llvm_from_ci {
1419                 crate::native::maybe_download_ci_llvm(builder);
1420                 let ci_llvm = builder.config.ci_llvm_root();
1421                 let link_type = t!(
1422                     std::fs::read_to_string(ci_llvm.join("link-type.txt")),
1423                     format!("CI llvm missing: {}", ci_llvm.display())
1424                 );
1425                 link_type == "dynamic"
1426             } else {
1427                 // unclear how thought-through this default is, but it maintains compatibility with
1428                 // previous behavior
1429                 false
1430             }
1431         });
1432         builder.config.llvm_link_shared.set(opt);
1433         llvm_link_shared
1434     }
1435
1436     /// Return whether we will use a downloaded, pre-compiled version of rustc, or just build from source.
1437     pub(crate) fn download_rustc(builder: &Builder<'_>) -> bool {
1438         static DOWNLOAD_RUSTC: OnceCell<bool> = OnceCell::new();
1439         if builder.config.dry_run && DOWNLOAD_RUSTC.get().is_none() {
1440             // avoid trying to actually download the commit
1441             return false;
1442         }
1443
1444         *DOWNLOAD_RUSTC.get_or_init(|| match &builder.config.download_rustc_commit {
1445             None => false,
1446             Some(commit) => {
1447                 download_ci_rustc(builder, commit);
1448                 true
1449             }
1450         })
1451     }
1452
1453     pub(crate) fn initial_rustfmt(builder: &Builder<'_>) -> Option<PathBuf> {
1454         match &mut *builder.config.initial_rustfmt.borrow_mut() {
1455             RustfmtState::SystemToolchain(p) | RustfmtState::Downloaded(p) => Some(p.clone()),
1456             RustfmtState::Unavailable => None,
1457             r @ RustfmtState::LazyEvaluated => {
1458                 if builder.config.dry_run {
1459                     return Some(PathBuf::new());
1460                 }
1461                 let path = maybe_download_rustfmt(builder);
1462                 *r = if let Some(p) = &path {
1463                     RustfmtState::Downloaded(p.clone())
1464                 } else {
1465                     RustfmtState::Unavailable
1466                 };
1467                 path
1468             }
1469         }
1470     }
1471
1472     pub fn verbose(&self) -> bool {
1473         self.verbose > 0
1474     }
1475
1476     pub fn sanitizers_enabled(&self, target: TargetSelection) -> bool {
1477         self.target_config.get(&target).map(|t| t.sanitizers).flatten().unwrap_or(self.sanitizers)
1478     }
1479
1480     pub fn any_sanitizers_enabled(&self) -> bool {
1481         self.target_config.values().any(|t| t.sanitizers == Some(true)) || self.sanitizers
1482     }
1483
1484     pub fn profiler_enabled(&self, target: TargetSelection) -> bool {
1485         self.target_config.get(&target).map(|t| t.profiler).flatten().unwrap_or(self.profiler)
1486     }
1487
1488     pub fn any_profiler_enabled(&self) -> bool {
1489         self.target_config.values().any(|t| t.profiler == Some(true)) || self.profiler
1490     }
1491
1492     pub fn llvm_enabled(&self) -> bool {
1493         self.rust_codegen_backends.contains(&INTERNER.intern_str("llvm"))
1494     }
1495
1496     pub fn llvm_libunwind(&self, target: TargetSelection) -> LlvmLibunwind {
1497         self.target_config
1498             .get(&target)
1499             .and_then(|t| t.llvm_libunwind)
1500             .or(self.llvm_libunwind_default)
1501             .unwrap_or(if target.contains("fuchsia") {
1502                 LlvmLibunwind::InTree
1503             } else {
1504                 LlvmLibunwind::No
1505             })
1506     }
1507
1508     pub fn submodules(&self, rust_info: &GitInfo) -> bool {
1509         self.submodules.unwrap_or(rust_info.is_managed_git_subrepository())
1510     }
1511 }
1512
1513 fn set<T>(field: &mut T, val: Option<T>) {
1514     if let Some(v) = val {
1515         *field = v;
1516     }
1517 }
1518
1519 fn threads_from_config(v: u32) -> u32 {
1520     match v {
1521         0 => std::thread::available_parallelism().map_or(1, std::num::NonZeroUsize::get) as u32,
1522         n => n,
1523     }
1524 }
1525
1526 /// Returns the commit to download, or `None` if we shouldn't download CI artifacts.
1527 fn download_ci_rustc_commit(
1528     config: &Config,
1529     download_rustc: Option<StringOrBool>,
1530 ) -> Option<String> {
1531     // If `download-rustc` is not set, default to rebuilding.
1532     let if_unchanged = match download_rustc {
1533         None | Some(StringOrBool::Bool(false)) => return None,
1534         Some(StringOrBool::Bool(true)) => false,
1535         Some(StringOrBool::String(s)) if s == "if-unchanged" => true,
1536         Some(StringOrBool::String(other)) => {
1537             panic!("unrecognized option for download-rustc: {}", other)
1538         }
1539     };
1540
1541     // Handle running from a directory other than the top level
1542     let top_level = output(config.git().args(&["rev-parse", "--show-toplevel"]));
1543     let top_level = top_level.trim_end();
1544     let compiler = format!("{top_level}/compiler/");
1545     let library = format!("{top_level}/library/");
1546
1547     // Look for a version to compare to based on the current commit.
1548     // Only commits merged by bors will have CI artifacts.
1549     let merge_base = output(
1550         config
1551             .git()
1552             .arg("rev-list")
1553             .arg(format!("--author={}", config.stage0_metadata.config.git_merge_commit_email))
1554             .args(&["-n1", "--first-parent", "HEAD"]),
1555     );
1556     let commit = merge_base.trim_end();
1557     if commit.is_empty() {
1558         println!("error: could not find commit hash for downloading rustc");
1559         println!("help: maybe your repository history is too shallow?");
1560         println!("help: consider disabling `download-rustc`");
1561         println!("help: or fetch enough history to include one upstream commit");
1562         crate::detail_exit(1);
1563     }
1564
1565     // Warn if there were changes to the compiler or standard library since the ancestor commit.
1566     let has_changes = !t!(config
1567         .git()
1568         .args(&["diff-index", "--quiet", &commit, "--", &compiler, &library])
1569         .status())
1570     .success();
1571     if has_changes {
1572         if if_unchanged {
1573             if config.verbose > 0 {
1574                 println!(
1575                     "warning: saw changes to compiler/ or library/ since {commit}; \
1576                           ignoring `download-rustc`"
1577                 );
1578             }
1579             return None;
1580         }
1581         println!(
1582             "warning: `download-rustc` is enabled, but there are changes to \
1583                   compiler/ or library/"
1584         );
1585     }
1586
1587     Some(commit.to_string())
1588 }
1589
1590 fn maybe_download_rustfmt(builder: &Builder<'_>) -> Option<PathBuf> {
1591     let RustfmtMetadata { date, version } = builder.config.stage0_metadata.rustfmt.as_ref()?;
1592     let channel = format!("{version}-{date}");
1593
1594     let host = builder.config.build;
1595     let rustfmt_path = builder.config.initial_rustc.with_file_name(exe("rustfmt", host));
1596     let bin_root = builder.config.out.join(host.triple).join("stage0");
1597     let rustfmt_stamp = bin_root.join(".rustfmt-stamp");
1598     if rustfmt_path.exists() && !program_out_of_date(&rustfmt_stamp, &channel) {
1599         return Some(rustfmt_path);
1600     }
1601
1602     let filename = format!("rustfmt-{version}-{build}.tar.xz", build = host.triple);
1603     download_component(builder, DownloadSource::Dist, filename, "rustfmt-preview", &date, "stage0");
1604
1605     builder.fix_bin_or_dylib(&bin_root.join("bin").join("rustfmt"));
1606     builder.fix_bin_or_dylib(&bin_root.join("bin").join("cargo-fmt"));
1607
1608     builder.create(&rustfmt_stamp, &channel);
1609     Some(rustfmt_path)
1610 }
1611
1612 fn download_ci_rustc(builder: &Builder<'_>, commit: &str) {
1613     builder.verbose(&format!("using downloaded stage2 artifacts from CI (commit {commit})"));
1614     let channel = builder.config.artifact_channel(builder, commit);
1615     let host = builder.config.build.triple;
1616     let bin_root = builder.out.join(host).join("ci-rustc");
1617     let rustc_stamp = bin_root.join(".rustc-stamp");
1618
1619     if !bin_root.join("bin").join("rustc").exists() || program_out_of_date(&rustc_stamp, commit) {
1620         if bin_root.exists() {
1621             t!(fs::remove_dir_all(&bin_root));
1622         }
1623         let filename = format!("rust-std-{channel}-{host}.tar.xz");
1624         let pattern = format!("rust-std-{host}");
1625         download_ci_component(builder, filename, &pattern, commit);
1626         let filename = format!("rustc-{channel}-{host}.tar.xz");
1627         download_ci_component(builder, filename, "rustc", commit);
1628         // download-rustc doesn't need its own cargo, it can just use beta's.
1629         let filename = format!("rustc-dev-{channel}-{host}.tar.xz");
1630         download_ci_component(builder, filename, "rustc-dev", commit);
1631
1632         builder.fix_bin_or_dylib(&bin_root.join("bin").join("rustc"));
1633         builder.fix_bin_or_dylib(&bin_root.join("bin").join("rustdoc"));
1634         let lib_dir = bin_root.join("lib");
1635         for lib in t!(fs::read_dir(&lib_dir), lib_dir.display().to_string()) {
1636             let lib = t!(lib);
1637             if lib.path().extension() == Some(OsStr::new("so")) {
1638                 builder.fix_bin_or_dylib(&lib.path());
1639             }
1640         }
1641         t!(fs::write(rustc_stamp, commit));
1642     }
1643 }
1644
1645 pub(crate) enum DownloadSource {
1646     CI,
1647     Dist,
1648 }
1649
1650 /// Download a single component of a CI-built toolchain (not necessarily a published nightly).
1651 // NOTE: intentionally takes an owned string to avoid downloading multiple times by accident
1652 fn download_ci_component(builder: &Builder<'_>, filename: String, prefix: &str, commit: &str) {
1653     download_component(builder, DownloadSource::CI, filename, prefix, commit, "ci-rustc")
1654 }
1655
1656 fn download_component(
1657     builder: &Builder<'_>,
1658     mode: DownloadSource,
1659     filename: String,
1660     prefix: &str,
1661     key: &str,
1662     destination: &str,
1663 ) {
1664     let cache_dst = builder.out.join("cache");
1665     let cache_dir = cache_dst.join(key);
1666     if !cache_dir.exists() {
1667         t!(fs::create_dir_all(&cache_dir));
1668     }
1669
1670     let bin_root = builder.out.join(builder.config.build.triple).join(destination);
1671     let tarball = cache_dir.join(&filename);
1672     let (base_url, url, should_verify) = match mode {
1673         DownloadSource::CI => (
1674             builder.config.stage0_metadata.config.artifacts_server.clone(),
1675             format!("{key}/{filename}"),
1676             false,
1677         ),
1678         DownloadSource::Dist => {
1679             let dist_server = env::var("RUSTUP_DIST_SERVER")
1680                 .unwrap_or(builder.config.stage0_metadata.config.dist_server.to_string());
1681             // NOTE: make `dist` part of the URL because that's how it's stored in src/stage0.json
1682             (dist_server, format!("dist/{key}/{filename}"), true)
1683         }
1684     };
1685
1686     // For the beta compiler, put special effort into ensuring the checksums are valid.
1687     // FIXME: maybe we should do this for download-rustc as well? but it would be a pain to update
1688     // this on each and every nightly ...
1689     let checksum = if should_verify {
1690         let error = format!(
1691             "src/stage0.json doesn't contain a checksum for {url}. \
1692             Pre-built artifacts might not be available for this \
1693             target at this time, see https://doc.rust-lang.org/nightly\
1694             /rustc/platform-support.html for more information."
1695         );
1696         let sha256 = builder.config.stage0_metadata.checksums_sha256.get(&url).expect(&error);
1697         if tarball.exists() {
1698             if builder.verify(&tarball, sha256) {
1699                 builder.unpack(&tarball, &bin_root, prefix);
1700                 return;
1701             } else {
1702                 builder.verbose(&format!(
1703                     "ignoring cached file {} due to failed verification",
1704                     tarball.display()
1705                 ));
1706                 builder.remove(&tarball);
1707             }
1708         }
1709         Some(sha256)
1710     } else if tarball.exists() {
1711         builder.unpack(&tarball, &bin_root, prefix);
1712         return;
1713     } else {
1714         None
1715     };
1716
1717     builder.download_component(&format!("{base_url}/{url}"), &tarball, "");
1718     if let Some(sha256) = checksum {
1719         if !builder.verify(&tarball, sha256) {
1720             panic!("failed to verify {}", tarball.display());
1721         }
1722     }
1723
1724     builder.unpack(&tarball, &bin_root, prefix);
1725 }