From 184bc480d753610efbcb0731f7f4c2ba2bdce256 Mon Sep 17 00:00:00 2001
From: Song Liu <songliubraving@fb.com>
Date: Wed, 13 Oct 2021 01:03:55 -0700
Subject: [PATCH] kpatch-build: add support for clang pgo
For clang with Profile-Guided Optimization (PGO), profile data is needed
to compile the livepatch properly. Add option -p|--profile-data, which
specifies the profile data file. This option is only valid with
CONFIG_CC_IS_CLANG and CONFIG_PGO_CLANG.
Signed-off-by: Song Liu <songliubraving@fb.com>
---
kpatch-build/kpatch-build | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/kpatch-build/kpatch-build b/kpatch-build/kpatch-build
index 634095d5..1f3fc99b 100755
--- a/kpatch-build/kpatch-build
+++ b/kpatch-build/kpatch-build
@@ -535,9 +535,10 @@ usage() {
echo " --skip-cleanup Skip post-build cleanup" >&2
echo " --skip-compiler-check Skip compiler version matching check" >&2
echo " (not recommended)" >&2
+ echo " -p, --profile-data specify profile data for PGO (clang only)" >&2
}
-options="$(getopt -o ha:r:s:c:v:j:t:n:o:dR -l "help,archversion:,sourcerpm:,sourcedir:,config:,vmlinux:,jobs:,target:,name:,output:,oot-module:,oot-module-src:,debug,skip-gcc-check,skip-compiler-check,skip-cleanup,non-replace" -- "$@")" || die "getopt failed"
+options="$(getopt -o ha:r:s:c:v:j:t:n:o:dRp: -l "help,archversion:,sourcerpm:,sourcedir:,config:,vmlinux:,jobs:,target:,name:,output:,oot-module:,oot-module-src:,debug,skip-gcc-check,skip-compiler-check,skip-cleanup,non-replace,profile-data" -- "$@")" || die "getopt failed"
eval set -- "$options"
@@ -619,6 +620,10 @@ while [[ $# -gt 0 ]]; do
echo "WARNING: Skipping compiler version matching check (not recommended)"
SKIPCOMPILERCHECK=1
;;
+ -p|--profile-data)
+ PROFILE_DATA="$(readlink -f "$2")"
+ shift
+ ;;
*)
[[ "$1" = "--" ]] && shift && continue
[[ ! -f "$1" ]] && die "patch file '$1' not found"
@@ -896,6 +901,16 @@ fi
if [[ -n "$CONFIG_CC_IS_CLANG" ]]; then
echo "WARNING: Clang support is experimental"
+ if [[ -z "$PROFILE_DATA" ]] && [[ -n "$CONFIG_PGO_CLANG" ]]; then
+ die "Please specify profile-data for CONFIG_PGO_CLANG"
+ fi
+ if [[ -n "$PROFILE_DATA" ]] && [[ -z "$CONFIG_PGO_CLANG" ]]; then
+ echo "WARNING profile-data specified w/o CONFIG_PGO_CLANG, ignore it"
+ fi
+else
+ if [[ -n "$PROFILE_DATA" ]]; then
+ die "Only supports profile-data with Clang"
+ fi
fi
if [[ "$SKIPCOMPILERCHECK" -eq 0 ]]; then
@@ -943,6 +958,9 @@ declare -a MAKEVARS
if [[ -n "$CONFIG_CC_IS_CLANG" ]]; then
MAKEVARS+=("CC=${KPATCH_CC_PREFIX}${CLANG}")
MAKEVARS+=("HOSTCC=clang")
+ if [[ -n "$CONFIG_PGO_CLANG" ]]; then
+ MAKEVARS+=("CFLAGS_PGO_CLANG=-fprofile-use=$PROFILE_DATA")
+ fi
else
MAKEVARS+=("CC=${KPATCH_CC_PREFIX}${GCC}")
fi