Skip to content

Commit

Permalink
Browse files Browse the repository at this point in the history
Move LLVM profiling to a separate phase of compilation
  • Loading branch information
Mark-Simulacrum committed Oct 14, 2021
1 parent c34ac87 commit f70232f
Showing 1 changed file with 30 additions and 8 deletions.
38 changes: 30 additions & 8 deletions src/ci/pgo.sh
Expand Up @@ -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
Expand All @@ -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 $(whoami): ./rustc-perf
cd rustc-perf
Expand Down Expand Up @@ -46,18 +73,13 @@ cd /checkout/obj
./build/$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

0 comments on commit f70232f

Please sign in to comment.