Rollup merge of #127002 - Kobzol:bootstrap-perf-tool, r=onur-ozkan

Implement `x perf` as a separate tool

Continues work from https://github.com/rust-lang/rust/pull/126318, adds a CLI for running `rustc-perf` profiling commands through a new `rustc-perf-wrapper` tool. The CLI is in a separate tool to enable experimentation outside of `bootstrap`.

This is probably most of what we can do so far, I'll add support for benchmarking once `rustc-perf` gets a terminal output for comparing benchmark results.

r? ``@onur-ozkan``

3 files changed, 15 insertions, 22 deletions

diff --git a/src/bootstrap/src/core/build_steps/perf.rs b/src/bootstrap/src/core/build_steps/perf.rs
index 9d70ca6bd71..f41b5fe10f1 100644
--- a/src/bootstrap/src/core/build_steps/perf.rs
+++ b/src/bootstrap/src/core/build_steps/perf.rs
@@ -1,7 +1,5 @@
-use std::process::Command;
-
 use crate::core::build_steps::compile::{Std, Sysroot};
-use crate::core::build_steps::tool::RustcPerf;
+use crate::core::build_steps::tool::{RustcPerf, Tool};
 use crate::core::builder::Builder;
 use crate::core::config::DebuginfoLevel;
 
@@ -22,24 +20,16 @@ Consider setting `rust.debuginfo-level = 1` in `config.toml`."#);
     let sysroot = builder.ensure(Sysroot::new(compiler));
     let rustc = sysroot.join("bin/rustc");
 
-    let results_dir = builder.build.tempdir().join("rustc-perf");
-
-    let mut cmd = Command::new(collector);
-    let cmd = cmd
-        .arg("profile_local")
-        .arg("eprintln")
-        .arg("--out-dir")
-        .arg(&results_dir)
-        .arg("--include")
-        .arg("helloworld")
-        .arg(&rustc);
-
-    builder.info(&format!("Running `rustc-perf` using `{}`", rustc.display()));
+    let rustc_perf_dir = builder.build.tempdir().join("rustc-perf");
+    let profile_results_dir = rustc_perf_dir.join("results");
 
-    // We need to set the working directory to `src/tools/perf`, so that it can find the directory
-    // with compile-time benchmarks.
-    let cmd = cmd.current_dir(builder.src.join("src/tools/rustc-perf"));
-    builder.build.run(cmd);
+    // We need to take args passed after `--` and pass them to `rustc-perf-wrapper`
+    let args = std::env::args().skip_while(|a| a != "--").skip(1);
 
-    builder.info(&format!("You can find the results at `{}`", results_dir.display()));
+    let mut cmd = builder.tool_cmd(Tool::RustcPerfWrapper);
+    cmd.env("RUSTC_REAL", rustc)
+        .env("PERF_COLLECTOR", collector)
+        .env("PERF_RESULT_DIR", profile_results_dir)
+        .args(args);
+    builder.run(&mut cmd);
 }
diff --git a/src/bootstrap/src/core/build_steps/tool.rs b/src/bootstrap/src/core/build_steps/tool.rs
index f6258121c50..b3464043912 100644
--- a/src/bootstrap/src/core/build_steps/tool.rs
+++ b/src/bootstrap/src/core/build_steps/tool.rs
@@ -337,6 +337,7 @@ bootstrap_tool!(
     GenerateWindowsSys, "src/tools/generate-windows-sys", "generate-windows-sys";
     RustdocGUITest, "src/tools/rustdoc-gui-test", "rustdoc-gui-test", is_unstable_tool = true, allow_features = "test";
     CoverageDump, "src/tools/coverage-dump", "coverage-dump";
+    RustcPerfWrapper, "src/tools/rustc-perf-wrapper", "rustc-perf-wrapper";
 );
 
 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
diff --git a/src/bootstrap/src/core/config/flags.rs b/src/bootstrap/src/core/config/flags.rs
index eb5152a3831..aeb608a9ea2 100644
--- a/src/bootstrap/src/core/config/flags.rs
+++ b/src/bootstrap/src/core/config/flags.rs
@@ -470,7 +470,9 @@ Arguments:
         versioned_dirs: bool,
     },
     /// Perform profiling and benchmarking of the compiler using the
-    /// `rustc-perf` benchmark suite.
+    /// `rustc-perf-wrapper` tool.
+    ///
+    /// You need to pass arguments after `--`, e.g.`x perf -- cachegrind`.
     Perf {},
 }