WIP: Add initial support for running Miri flamegraph (no flamegraph options yet)

Author: Patrick-6

Cargo.toml

@@ -17,6 +17,9 @@ name = "miri"
 test = false    # we have no unit tests
 doctest = false # and no doc tests
 
+[profile.bench]
+debug = true
+
 [dependencies]
 getrandom = { version = "0.3", features = ["std"] }
 rand = "0.9"

miri-script/src/commands.rs

@@ -112,8 +112,8 @@ impl Command {
             Command::Check { features, flags } => Self::check(features, flags),
             Command::Test { bless, target, coverage, features, flags } =>
                 Self::test(bless, target, coverage, features, flags),
-            Command::Run { dep, verbose, target, edition, features, flags } =>
-                Self::run(dep, verbose, target, edition, features, flags),
+            Command::Run { dep, verbose, target, edition, features, flags, flamegraph } =>
+                Self::run(dep, verbose, target, edition, features, flags, flamegraph),
             Command::Doc { features, flags } => Self::doc(features, flags),
             Command::Fmt { flags } => Self::fmt(flags),
             Command::Clippy { features, flags } => Self::clippy(features, flags),
@@ -463,6 +463,7 @@ impl Command {
         edition: Option<String>,
         features: Vec<String>,
         flags: Vec<String>,
+        flamegraph: bool,
     ) -> Result<()> {
         let mut e = MiriEnv::new()?;
 
@@ -498,11 +499,14 @@ impl Command {
         // The basic command that executes the Miri driver.
         let mut cmd = if dep {
             // We invoke the test suite as that has all the logic for running with dependencies.
-            e.cargo_cmd(".", "test", &features)
-                .args(&["--test", "ui"])
-                .args(quiet_flag)
-                .arg("--")
-                .args(&["--miri-run-dep-mode"])
+            let cmd = e.cargo_cmd(".", "test", &features).args(&["--test", "ui"]).args(quiet_flag).arg("--");
+            if flamegraph {
+                cmd.args(&["--miri-run-dep-mode-flamegraph"])
+            } else {
+                cmd.args(&["--miri-run-dep-mode"])
+            }
+        } else if flamegraph {
+            cmd!(e.sh, "flamegraph -- {miri_bin}")
         } else {
             cmd!(e.sh, "{miri_bin}")
         };

miri-script/src/main.rs

@@ -96,6 +96,9 @@ pub enum Command {
         /// The flags set in `MIRIFLAGS` are added in front of these flags.
         #[arg(trailing_var_arg = true, allow_hyphen_values = true)]
         flags: Vec<String>,
+        /// Run with flamegraph (requires cargo-flamegraph to be installed)
+        #[arg(long)]
+        flamegraph: bool,
     },
     /// Build documentation.
     Doc {

tests/ui.rs

@@ -322,10 +322,12 @@ fn main() -> Result<()> {
     let mut args = std::env::args_os();
 
     // Skip the program name and check whether this is a `./miri run-dep` invocation
-    if let Some(first) = args.nth(1)
-        && first == "--miri-run-dep-mode"
-    {
-        return run_dep_mode(target, args);
+    if let Some(first) = args.nth(1) {
+        if first == "--miri-run-dep-mode" {
+            return run_dep_mode(target, args, /* flamegraph */ false);
+        } else if first == "--miri-run-dep-mode-flamegraph" {
+            return run_dep_mode(target, args, /* flamegraph */ true);
+        }
     }
 
     ui(Mode::Pass, "tests/pass", &target, WithoutDependencies, tmpdir.path())?;
@@ -355,7 +357,11 @@ fn main() -> Result<()> {
     Ok(())
 }
 
-fn run_dep_mode(target: String, args: impl Iterator<Item = OsString>) -> Result<()> {
+fn run_dep_mode(
+    target: String,
+    args: impl Iterator<Item = OsString>,
+    flamegraph: bool,
+) -> Result<()> {
     let mut config =
         miri_config(&target, "", Mode::RunDep, Some(WithDependencies { bless: false }));
     config.comment_defaults.base().custom.remove("edition"); // `./miri` adds an `--edition` in `args`, so don't set it twice
@@ -370,5 +376,11 @@ fn run_dep_mode(target: String, args: impl Iterator<Item = OsString>) -> Result<
     // Build dependencies
     test_config.apply_custom(&mut cmd, &build_manager).unwrap();
 
+    if flamegraph {
+        let mut flamegraph_cmd = Command::new("flamegraph");
+        flamegraph_cmd.arg("--").arg(cmd.get_program()).args(cmd.get_args());
+        cmd = flamegraph_cmd;
+    }
+
     if cmd.spawn()?.wait()?.success() { Ok(()) } else { std::process::exit(1) }
 }