From f70232f81ac164d87195e31a157f52d0681f967c Mon Sep 17 00:00:00 2001
From: Mark Rousskov <mark.simulacrum@gmail.com>
Date: Thu, 14 Oct 2021 10:19:03 -0400
Subject: [PATCH 1/2] Move LLVM profiling to a separate phase of compilation
---
src/ci/pgo.sh | 38 ++++++++++++++++++++++++++++++--------
1 file changed, 30 insertions(+), 8 deletions(-)
diff --git a/src/ci/pgo.sh b/src/ci/pgo.sh
index e35e3e670cc64..29ef13a60fbc4 100755
--- a/src/ci/pgo.sh
+++ b/src/ci/pgo.sh
@@ -4,9 +4,13 @@ set -euxo pipefail
rm -rf /tmp/rustc-pgo
+# We collect LLVM profiling information and rustc profiling information in
+# separate phases. This increases build time -- though not by a huge amount --
+# but prevents any problems from arising due to different profiling runtimes
+# being simultaneously linked in.
+
python3 ../x.py build --target=$PGO_HOST --host=$PGO_HOST \
--stage 2 library/std \
- --rust-profile-generate=/tmp/rustc-pgo \
--llvm-profile-generate
# Profile libcore compilation in opt-level=0 and opt-level=3
@@ -15,6 +19,29 @@ RUSTC_BOOTSTRAP=1 ./build/$PGO_HOST/stage2/bin/rustc --edition=2018 \
RUSTC_BOOTSTRAP=1 ./build/$PGO_HOST/stage2/bin/rustc --edition=2018 \
--crate-type=lib -Copt-level=3 ../library/core/src/lib.rs
+# Merge the profile data we gathered for LLVM
+# Note that this uses the profdata from the clang we used to build LLVM,
+# which likely has a different version than our in-tree clang.
+/rustroot/bin/llvm-profdata \
+ merge -o /tmp/llvm-pgo.profdata ./build/$PGO_HOST/llvm/build/profiles
+
+# Rustbuild currently doesn't support rebuilding LLVM when PGO options
+# change (or any other llvm-related options); so just clear out the relevant
+# directories ourselves.
+rm -r ./build/$PGO_HOST/llvm ./build/$PGO_HOST/lld
+
+# Okay, LLVM profiling is done, switch to rustc PGO.
+
+python3 ../x.py build --target=$PGO_HOST --host=$PGO_HOST \
+ --stage 2 library/std \
+ --rust-profile-generate=/tmp/rustc-pgo
+
+# Profile libcore compilation in opt-level=0 and opt-level=3
+RUSTC_BOOTSTRAP=1 ./build/$PGO_HOST/stage2/bin/rustc --edition=2018 \
+ --crate-type=lib ../library/core/src/lib.rs
+RUSTC_BOOTSTRAP=1 ./build/$PGO_HOST/stage2/bin/rustc --edition=2018 \
+ --crate-type=lib -Copt-level=3 ../library/core/src/lib.rs
+
cp -r /tmp/rustc-perf ./
chown -R $(whoami): ./rustc-perf
cd rustc-perf
@@ -46,18 +73,13 @@ cd /checkout/obj
./build/$PGO_HOST/llvm/bin/llvm-profdata \
merge -o /tmp/rustc-pgo.profdata /tmp/rustc-pgo
-# Merge the profile data we gathered for LLVM
-# Note that this uses the profdata from the clang we used to build LLVM,
-# which likely has a different version than our in-tree clang.
-/rustroot/bin/llvm-profdata \
- merge -o /tmp/llvm-pgo.profdata ./build/$PGO_HOST/llvm/build/profiles
-
# Rustbuild currently doesn't support rebuilding LLVM when PGO options
# change (or any other llvm-related options); so just clear out the relevant
# directories ourselves.
rm -r ./build/$PGO_HOST/llvm ./build/$PGO_HOST/lld
-# This produces the actual final set of artifacts.
+# This produces the actual final set of artifacts, using both the LLVM and rustc
+# collected profiling data.
$@ \
--rust-profile-use=/tmp/rustc-pgo.profdata \
--llvm-profile-use=/tmp/llvm-pgo.profdata
From 86608f1796c9335b103b596df53bef03f7fcc303 Mon Sep 17 00:00:00 2001
From: Mark Rousskov <mark.simulacrum@gmail.com>
Date: Thu, 14 Oct 2021 15:20:52 -0400
Subject: [PATCH 2/2] Switch to clang v13 as the C/C++ compiler used for
bootstrap
---
src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh b/src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh
index ed5edfec4e1a6..562be752f846d 100755
--- a/src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh
+++ b/src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh
@@ -4,7 +4,7 @@ set -ex
source shared.sh
-LLVM=llvmorg-12.0.1
+LLVM=llvmorg-13.0.0
mkdir llvm-project
cd llvm-project