WIP: Add PGO for apple darwin targets

Author: osiewicz

src/bootstrap/src/core/build_steps/compile.rs

@@ -1388,12 +1388,19 @@ fn rustc_llvm_env(builder: &Builder<'_>, cargo: &mut Cargo, target: TargetSelect
     // found. This is to avoid the linker errors about undefined references to
     // `__llvm_profile_instrument_memop` when linking `rustc_driver`.
     let mut llvm_linker_flags = String::new();
-    if builder.config.llvm_profile_generate && target.is_msvc() {
-        if let Some(ref clang_cl_path) = builder.config.llvm_clang_cl {
-            // Add clang's runtime library directory to the search path
-            let clang_rt_dir = get_clang_cl_resource_dir(builder, clang_cl_path);
-            llvm_linker_flags.push_str(&format!("-L{}", clang_rt_dir.display()));
+    if builder.config.llvm_profile_generate {
+        if target.is_msvc() {
+            if let Some(ref clang_cl_path) = builder.config.llvm_clang_cl {
+                // Add clang's runtime library directory to the search path
+                let clang_rt_dir = get_clang_cl_resource_dir(builder, clang_cl_path);
+                llvm_linker_flags.push_str(&format!("-L{}", clang_rt_dir.display()));
+            }
+        } else  {
+
+            llvm_linker_flags.push_str("-L/opt/homebrew/Cellar/llvm/20.1.2/lib/clang/20/lib/darwin/lib -lclang_rt.profile_osx");
+
         }
+
     }
 
     // The config can also specify its own llvm linker flags.

src/ci/github-actions/jobs.yml

@@ -425,7 +425,7 @@ auto:
 
   - name: dist-aarch64-apple
     env:
-      SCRIPT: ./x.py dist bootstrap --include-default-paths --host=aarch64-apple-darwin --target=aarch64-apple-darwin
+      SCRIPT: ./x.py build --set rust.debug=true opt-dist && PGO_HOST=aarch64-apple-darwin ./build/aarch64-apple-darwin/stage0-tools-bin/opt-dist mac-ci -- python3 x.py dist bootstrap --include-default-paths
       RUST_CONFIGURE_ARGS: >-
         --enable-full-tools
         --enable-sanitizers

src/tools/opt-dist/src/main.rs

@@ -109,6 +109,10 @@ enum EnvironmentCmd {
         #[clap(flatten)]
         shared: SharedArgs,
     },
+    MacCi {
+        #[clap(flatten)]
+        shared: SharedArgs,
+    }
 }
 
 fn is_try_build() -> bool {
@@ -191,6 +195,26 @@ fn create_environment(args: Args) -> anyhow::Result<(Environment, Vec<String>)>
 
             (env, shared.build_args)
         }
+        EnvironmentCmd::MacCi { shared } => {
+            let target_triple =
+                std::env::var("PGO_HOST").expect("PGO_HOST environment variable missing");
+
+            let checkout_dir: Utf8PathBuf = std::env::current_dir()?.try_into()?;
+            let env = EnvironmentBuilder::default()
+                .host_tuple(target_triple)
+                .python_binary("python3".to_string())
+                .checkout_dir(checkout_dir.clone())
+                .host_llvm_dir("/opt/homebrew/Cellar/llvm/20.1.2".into())
+                .artifact_dir(checkout_dir.join("opt-artifacts"))
+                .build_dir(checkout_dir)
+                .shared_llvm(false)
+                .use_bolt(false)
+                .run_tests(false)
+                .skipped_tests(vec![])
+                .build()?;
+
+            (env, shared.build_args)
+        }
     };
     Ok((env, args))
 }
@@ -250,6 +274,9 @@ fn execute_pipeline(
     // Here we build a PGO instrumented LLVM, reusing the previously PGO optimized rustc.
     // Then we use the instrumented LLVM to gather LLVM PGO profiles.
     let llvm_pgo_profile = timer.section("Stage 2 (LLVM PGO)", |stage| {
+        if 1 + 1 == 2 {
+            return Err(anyhow::anyhow!("disabled"));
+        }
         // Remove the previous, uninstrumented build of LLVM.
         clear_llvm_files(env)?;
 
@@ -272,7 +299,7 @@ fn execute_pipeline(
         clear_llvm_files(env)?;
 
         Ok(profile)
-    })?;
+    });
 
     let bolt_profiles = if env.use_bolt() {
         // Stage 3: Build BOLT instrumented LLVM
@@ -284,7 +311,7 @@ fn execute_pipeline(
             stage.section("Build PGO optimized LLVM", |stage| {
                 Bootstrap::build(env)
                     .with_llvm_bolt_ldflags()
-                    .llvm_pgo_optimize(&llvm_pgo_profile)
+                    .llvm_pgo_optimize(&llvm_pgo_profile?)
                     .avoid_rustc_rebuild()
                     .run(stage)
             })?;
@@ -336,7 +363,6 @@ fn execute_pipeline(
     };
 
     let mut dist = Bootstrap::dist(env, &dist_args)
-        .llvm_pgo_optimize(&llvm_pgo_profile)
         .rustc_pgo_optimize(&rustc_pgo_profile)
         .avoid_rustc_rebuild();