bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'xtask/src/pgo.rs')
-rw-r--r--xtask/src/pgo.rs105
1 files changed, 105 insertions, 0 deletions
diff --git a/xtask/src/pgo.rs b/xtask/src/pgo.rs
new file mode 100644
index 0000000000..7f7b3311d9
--- /dev/null
+++ b/xtask/src/pgo.rs
@@ -0,0 +1,105 @@
+//! PGO (Profile-Guided Optimization) utilities.
+
+use anyhow::Context;
+use std::env::consts::EXE_EXTENSION;
+use std::ffi::OsStr;
+use std::path::{Path, PathBuf};
+use xshell::{Cmd, Shell, cmd};
+
+use crate::flags::PgoTrainingCrate;
+
+/// Decorates `ra_build_cmd` to add PGO instrumentation, and then runs the PGO instrumented
+/// Rust Analyzer on itself to gather a PGO profile.
+pub(crate) fn gather_pgo_profile<'a>(
+ sh: &'a Shell,
+ ra_build_cmd: Cmd<'a>,
+ target: &str,
+ train_crate: PgoTrainingCrate,
+) -> anyhow::Result<PathBuf> {
+ let pgo_dir = std::path::absolute("rust-analyzer-pgo")?;
+ // Clear out any stale profiles
+ if pgo_dir.is_dir() {
+ std::fs::remove_dir_all(&pgo_dir)?;
+ }
+ std::fs::create_dir_all(&pgo_dir)?;
+
+ // Figure out a path to `llvm-profdata`
+ let target_libdir = cmd!(sh, "rustc --print=target-libdir")
+ .read()
+ .context("cannot resolve target-libdir from rustc")?;
+ let target_bindir = PathBuf::from(target_libdir).parent().unwrap().join("bin");
+ let llvm_profdata = target_bindir.join("llvm-profdata").with_extension(EXE_EXTENSION);
+
+ // Build RA with PGO instrumentation
+ let cmd_gather =
+ ra_build_cmd.env("RUSTFLAGS", format!("-Cprofile-generate={}", pgo_dir.to_str().unwrap()));
+ cmd_gather.run().context("cannot build rust-analyzer with PGO instrumentation")?;
+
+ let (train_path, label) = match &train_crate {
+ PgoTrainingCrate::RustAnalyzer => (PathBuf::from("."), "itself"),
+ PgoTrainingCrate::GitHub(repo) => {
+ (download_crate_for_training(sh, &pgo_dir, repo)?, repo.as_str())
+ }
+ };
+
+ // Run RA either on itself or on a downloaded crate
+ eprintln!("Training RA on {label}...");
+ cmd!(
+ sh,
+ "target/{target}/release/rust-analyzer analysis-stats -q --run-all-ide-things {train_path}"
+ )
+ .run()
+ .context("cannot generate PGO profiles")?;
+
+ // Merge profiles into a single file
+ let merged_profile = pgo_dir.join("merged.profdata");
+ let profile_files = std::fs::read_dir(pgo_dir)?.filter_map(|entry| {
+ let entry = entry.ok()?;
+ if entry.path().extension() == Some(OsStr::new("profraw")) {
+ Some(entry.path().to_str().unwrap().to_owned())
+ } else {
+ None
+ }
+ });
+ cmd!(sh, "{llvm_profdata} merge {profile_files...} -o {merged_profile}").run().context(
+ "cannot merge PGO profiles. Do you have the rustup `llvm-tools` component installed?",
+ )?;
+
+ Ok(merged_profile)
+}
+
+/// Downloads a crate from GitHub, stores it into `pgo_dir` and returns a path to it.
+fn download_crate_for_training(sh: &Shell, pgo_dir: &Path, repo: &str) -> anyhow::Result<PathBuf> {
+ let mut it = repo.splitn(2, '@');
+ let repo = it.next().unwrap();
+ let revision = it.next();
+
+ // FIXME: switch to `--revision` here around 2035 or so
+ let revision =
+ if let Some(revision) = revision { &["--branch", revision] as &[&str] } else { &[] };
+
+ let normalized_path = repo.replace("/", "-");
+ let target_path = pgo_dir.join(normalized_path);
+ cmd!(sh, "git clone --depth 1 https://github.com/{repo} {revision...} {target_path}")
+ .run()
+ .with_context(|| "cannot download PGO training crate from {repo}")?;
+
+ Ok(target_path)
+}
+
+/// Helper function to create a build command for rust-analyzer
+pub(crate) fn build_command<'a>(
+ sh: &'a Shell,
+ command: &str,
+ target_name: &str,
+ features: &[&str],
+) -> Cmd<'a> {
+ cmd!(
+ sh,
+ "cargo {command} --manifest-path ./crates/rust-analyzer/Cargo.toml --bin rust-analyzer --target {target_name} {features...} --release"
+ )
+}
+
+pub(crate) fn apply_pgo_to_cmd<'a>(cmd: Cmd<'a>, profile_path: &Path) -> Cmd<'a> {
+ cmd.env("RUSTFLAGS", format!("-Cprofile-use={}", profile_path.to_str().unwrap()))
+}