Bootstrap should skip preparing a linker for targets when checking std · Issue #128180 · rust-lang/rust (original) (raw)

Currently ./x check std --stage 0 --target <target> will attempt to configure the target linker and other tools even though they're unused. For the most part this just results in needless cc spam (and presumably slower checks). E.g.:

cargo:warning=Compiler family detection failed due to error: ToolNotFound: Failed to find tool. Is `arm-kmc-eabi-gcc` installed? (see https://github.com/rust-lang/cc-rs#compile-time-requirements for help)
cargo:warning=Compiler family detection failed due to error: ToolNotFound: Failed to find tool. Is `arm-kmc-eabi-g++` installed? (see https://github.com/rust-lang/cc-rs#compile-time-requirements for help)
cargo:warning=Compiler family detection failed due to error: ToolNotFound: Failed to find tool. Is `arm-kmc-eabi-g++` installed? (see https://github.com/rust-lang/cc-rs#compile-time-requirements for help)

But for apple targets this is often a hard failure unless you have the relevant tools. E.g.:

> ./x check std --target aarch64-apple-ios --stage 0
Building bootstrap
    Finished `dev` profile [unoptimized] target(s) in 0.07s


error occurred: Failed to find tool. Is `xcrun` installed? (see https://github.com/rust-lang/cc-rs#compile-time-requirements for help)


Build completed unsuccessfully in 0:00:00

I managed to hack around this issue but I don't know bootstrap code very well so a proper fix would be appreciated.

Hack

diff --git a/src/bootstrap/src/core/builder.rs b/src/bootstrap/src/core/builder.rs index 78fbea2e810..9d3c606aa01 100644 --- a/src/bootstrap/src/core/builder.rs +++ b/src/bootstrap/src/core/builder.rs @@ -2433,7 +2433,9 @@ pub fn new( cmd: &str, // FIXME make this properly typed ) -> Cargo { let mut cargo = builder.cargo(compiler, mode, source_type, target, cmd);

```
   cargo.configure_linker(builder);
```

```
   if cmd != "check" {
```
```
       cargo.configure_linker(builder);
```
```
   }
   cargo
```
}

diff --git a/src/bootstrap/src/utils/cc_detect.rs b/src/bootstrap/src/utils/cc_detect.rs index 20d79e490ec..dcc56de121f 100644 --- a/src/bootstrap/src/utils/cc_detect.rs +++ b/src/bootstrap/src/utils/cc_detect.rs @@ -89,13 +89,11 @@ fn new_cc_build(build: &Build, target: TargetSelection) -> cc::Build { pub fn find(build: &Build) { // For all targets we're going to need a C compiler for building some shims // and such as well as for being a linker for Rust code.

let targets = build
```
   .targets
```
```
   .iter()
```
```
   .chain(&build.hosts)
```
```
   .cloned()
```
```
   .chain(iter::once(build.build))
```
```
   .collect::<HashSet<_>>();
```

let targets: HashSet<_> = if matches!(build.config.cmd, crate::Subcommand::Check { .. }) {

   build.hosts.iter().cloned().chain(iter::once(build.build)).collect()

} else {

   build.targets.iter().chain(&build.hosts).cloned().chain(iter::once(build.build)).collect()

}; for target in targets.into_iter() { find_target(build, target); }