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Fix cross-compiling LLD to different platforms

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Looks like the native build system isn't great a coping with this, so
try to work around that with a few workarounds.
This commit is contained in:
Alex Crichton 2020-04-24 11:18:59 -07:00
parent c7a7658c6d
commit 0546d11528
2 changed files with 28 additions and 2 deletions
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9
src/bootstrap/bin/llvm-config-wrapper.rs
View File

@ -10,7 +10,14 @@ fn main() {
let mut cmd = Command::new(real_llvm_config);
cmd.args(env::args().skip(1)).stderr(Stdio::piped());
let output = cmd.output().expect("failed to spawn llvm-config");
let stdout = String::from_utf8_lossy(&output.stdout);
let mut stdout = String::from_utf8_lossy(&output.stdout);
if let Ok(to_replace) = env::var("LLVM_CONFIG_SHIM_REPLACE") {
if let Ok(replace_with) = env::var("LLVM_CONFIG_SHIM_REPLACE_WITH") {
stdout = stdout.replace(&to_replace, &replace_with).into();
}
}
print!("{}", stdout.replace("\\", "/"));
io::stdout().flush().unwrap();
process::exit(output.status.code().unwrap_or(1));

21
src/bootstrap/native.rs
View File

@ -479,10 +479,29 @@ fn run(self, builder: &Builder<'_>) -> PathBuf {
let llvm_config_shim = env::current_exe().unwrap().with_file_name("llvm-config-wrapper");
cfg.out_dir(&out_dir)
.profile("Release")
.env("LLVM_CONFIG_REAL", llvm_config)
.env("LLVM_CONFIG_REAL", &llvm_config)
.define("LLVM_CONFIG_PATH", llvm_config_shim)
.define("LLVM_INCLUDE_TESTS", "OFF");
// While we're using this horrible workaround to shim the execution of
// llvm-config, let's just pile on more. I can't seem to figure out how
// to build LLD as a standalone project and also cross-compile it at the
// same time. It wants a natively executable `llvm-config` to learn
// about LLVM, but then it learns about all the host configuration of
// LLVM and tries to link to host LLVM libraries.
//
// To work around that we tell our shim to replace anything with the
// build target with the actual target instead. This'll break parts of
// LLD though which try to execute host tools, such as llvm-tblgen, so
// we specifically tell it where to find those. This is likely super
// brittle and will break over time. If anyone knows better how to
// cross-compile LLD it would be much appreciated to fix this!
if target != builder.config.build {
cfg.env("LLVM_CONFIG_SHIM_REPLACE", &builder.config.build)
.env("LLVM_CONFIG_SHIM_REPLACE_WITH", &target)
.define("LLVM_TABLEGEN_EXE", llvm_config.with_file_name("llvm-tblgen"));
}
cfg.build();
t!(File::create(&done_stamp));