From abecaaed2046e1ed9980b513aecc48a1858d8b0e Mon Sep 17 00:00:00 2001
From: Joey Riches <josephriches@gmail.com>
Date: Tue, 22 Sep 2026 19:23:37 +0100
Subject: [PATCH] boulder: Clean out PGO profiling data between runs

Before, stale profiling data would remain present in-between runs
causing potentially stale data to affect optimization in the PGO use
stage.
---
 boulder/src/build.rs           | 12 ++++++------
 boulder/src/build/job.rs       |  4 ++++
 boulder/src/build/job/phase.rs |  4 ++--
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/boulder/src/build.rs b/boulder/src/build.rs
index 9c49fd5d9..4097d1f38 100644
--- a/boulder/src/build.rs
+++ b/boulder/src/build.rs
@@ -19,7 +19,7 @@ use nix::{
 use thiserror::Error;
 use tui::Styled;
 
-use self::job::Job;
+use self::job::{Job, pgo_dir};
 use crate::{
     Env, Macros, Paths, Recipe, Timing,
     architecture::BuildTarget,
@@ -196,16 +196,16 @@ impl Builder {
         for (i, target) in self.targets.iter().enumerate() {
             println!("{}", build_target_prefix(target.build_target, i));
 
+            // Clean out any pre-existing profiling data from PGO runs
+            if let Some(job) = target.jobs.iter().find(|job| job.pgo_stage.is_some()) {
+                util::recreate_dir(&pgo_dir(&job.build_dir))?;
+            }
+
             for (i, job) in target.jobs.iter().enumerate() {
                 let is_pgo = job.pgo_stage.is_some();
 
                 // Recreate work dir for each job
                 util::recreate_dir(&job.work_dir)?;
-                // Ensure pgo dir exists
-                if is_pgo {
-                    let pgo_dir = PathBuf::from(format!("{}-pgo", job.build_dir.display()));
-                    util::ensure_dir_exists(&pgo_dir)?;
-                }
 
                 if let Some(stage) = job.pgo_stage {
                     println!("{}", pgo_stage_prefix(stage, i));
diff --git a/boulder/src/build/job.rs b/boulder/src/build/job.rs
index 808716e7a..4b732fcd1 100644
--- a/boulder/src/build/job.rs
+++ b/boulder/src/build/job.rs
@@ -95,6 +95,10 @@ fn work_dir(build_dir: &Path, upstreams: &[Upstream]) -> PathBuf {
     work_dir
 }
 
+pub fn pgo_dir(build_dir: &Path) -> PathBuf {
+    PathBuf::from(format!("{}-pgo", build_dir.display()))
+}
+
 #[derive(Debug, Error)]
 pub enum Error {
     #[error("missing arch macros: {0}")]
diff --git a/boulder/src/build/job/phase.rs b/boulder/src/build/job/phase.rs
index 9610183aa..507b268a5 100644
--- a/boulder/src/build/job/phase.rs
+++ b/boulder/src/build/job/phase.rs
@@ -13,7 +13,7 @@ use crate::build::pgo;
 use crate::build::script::ScriptBundle;
 use crate::{Macros, Paths, Recipe, architecture::BuildTarget};
 
-use super::{Error, work_dir};
+use super::{Error, pgo_dir, work_dir};
 
 pub fn list(pgo_stage: Option<pgo::Stage>) -> Vec<Phase> {
     if matches!(pgo_stage, Some(pgo::Stage::One | pgo::Stage::Two)) {
@@ -216,7 +216,7 @@ impl Phase {
             env.add_builtin_string("pgo_stage", "NONE");
         }
 
-        env.add_builtin_string("pgo_dir", format!("{}-pgo", build_dir.display()));
+        env.add_builtin_string("pgo_dir", pgo_dir(&build_dir).display());
 
         add_tuning(target, pgo_stage, recipe, macros, &mut env)?;