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Auto merge of #114344 - Kobzol:opt-dist-llvm-profdata, r=nikic

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Use the correct `llvm-profdata` binary in `opt-dist`

Turns out that we were probably using the wrong `llvm-profdata` binary in the PGO script all along. This should resolve the performance regressions of switching the host LLVM to 17 ([host `llvm-profdata`](https://github.com/rust-lang/rust/pull/114297#issuecomment-1660521361), [target `llvm-profdata`](https://github.com/rust-lang/rust/pull/114297#issuecomment-1661127032)]).

r? `@nikic`
This commit is contained in:
bors 2023-08-07 18:34:03 +00:00
commit 03a119b0b0
1 changed files with 23 additions and 11 deletions
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30
src/tools/opt-dist/src/training.rs
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@ -66,18 +66,30 @@ fn init_compiler_benchmarks(
.workdir(&env.rustc_perf_dir())
}
/// Describes which `llvm-profdata` binary should be used for merging PGO profiles.
enum LlvmProfdata {
/// Use llvm-profdata from the host toolchain (i.e. from LLVM provided externally).
Host,
/// Use llvm-profdata from the target toolchain (i.e. from LLVM built from `src/llvm-project`).
Target,
}
fn merge_llvm_profiles(
env: &dyn Environment,
merged_path: &Utf8Path,
profile_dir: &Utf8Path,
profdata: LlvmProfdata,
) -> anyhow::Result<()> {
cmd(&[
env.downloaded_llvm_dir().join("bin/llvm-profdata").as_str(),
"merge",
"-o",
merged_path.as_str(),
profile_dir.as_str(),
])
let llvm_profdata = match profdata {
LlvmProfdata::Host => env.downloaded_llvm_dir().join("bin/llvm-profdata"),
LlvmProfdata::Target => env
.build_artifacts()
.join("llvm")
.join("build")
.join(format!("bin/llvm-profdata{}", env.executable_extension())),
};
cmd(&[llvm_profdata.as_str(), "merge", "-o", merged_path.as_str(), profile_dir.as_str()])
.run()
.context("Cannot merge LLVM profiles")?;
Ok(())
@ -118,7 +130,7 @@ pub fn gather_llvm_profiles(
let merged_profile = env.opt_artifacts().join("llvm-pgo.profdata");
log::info!("Merging LLVM PGO profiles to {merged_profile}");
merge_llvm_profiles(env, &merged_profile, profile_root)?;
merge_llvm_profiles(env, &merged_profile, profile_root, LlvmProfdata::Host)?;
log_profile_stats("LLVM", &merged_profile, profile_root)?;
// We don't need the individual .profraw files now that they have been merged
@ -154,7 +166,7 @@ pub fn gather_rustc_profiles(
let merged_profile = env.opt_artifacts().join("rustc-pgo.profdata");
log::info!("Merging Rustc PGO profiles to {merged_profile}");
merge_llvm_profiles(env, &merged_profile, profile_root)?;
merge_llvm_profiles(env, &merged_profile, profile_root, LlvmProfdata::Target)?;
log_profile_stats("Rustc", &merged_profile, profile_root)?;
// We don't need the individual .profraw files now that they have been merged