https://github.com/python/cpython/commit/b012f6817f80b646ec95b212b23e6a785200f862
commit: b012f6817f80b646ec95b212b23e6a785200f862
branch: 3.13
author: Victor Stinner <[email protected]>
committer: vstinner <[email protected]>
date: 2026-03-12T23:17:00Z
summary:
[3.13] gh-145801: Use gcc -fprofile-update=atomic for PGO builds (#145802)
(#145893)
gh-145801: Use gcc -fprofile-update=atomic for PGO builds (#145802)
When Python build is optimized with GCC using PGO, use
-fprofile-update=atomic option to use atomic operations when updating
profile information. This option reduces the risk of gcov Data Files
(.gcda) corruption which can cause random GCC crashes.
(cherry picked from commit 08a018ebe0d673e9c352f790d2e4604d69604188)
files:
A Misc/NEWS.d/next/Build/2026-03-11-11-58-42.gh-issue-145801.iCXa3v.rst
M configure
M configure.ac
diff --git
a/Misc/NEWS.d/next/Build/2026-03-11-11-58-42.gh-issue-145801.iCXa3v.rst
b/Misc/NEWS.d/next/Build/2026-03-11-11-58-42.gh-issue-145801.iCXa3v.rst
new file mode 100644
index 00000000000000..c5f3982cc5416c
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2026-03-11-11-58-42.gh-issue-145801.iCXa3v.rst
@@ -0,0 +1,4 @@
+When Python build is optimized with GCC using PGO, use
+``-fprofile-update=atomic`` option to use atomic operations when updating
+profile information. This option reduces the risk of gcov Data Files (.gcda)
+corruption which can cause random GCC crashes. Patch by Victor Stinner.
diff --git a/configure b/configure
index 49b6795703ac68..9ddb712b5344d4 100755
--- a/configure
+++ b/configure
@@ -8990,7 +8990,44 @@ case "$CC_BASENAME" in
fi
;;
*)
- PGO_PROF_GEN_FLAG="-fprofile-generate"
+ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether C
compiler accepts -fprofile-update=atomic" >&5
+printf %s "checking whether C compiler accepts -fprofile-update=atomic... "
>&6; }
+if test ${ax_cv_check_cflags___fprofile_update_atomic+y}
+then :
+ printf %s "(cached) " >&6
+else $as_nop
+
+ ax_check_save_flags=$CFLAGS
+ CFLAGS="$CFLAGS -fprofile-update=atomic"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+int
+main (void)
+{
+
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+ ax_cv_check_cflags___fprofile_update_atomic=yes
+else $as_nop
+ ax_cv_check_cflags___fprofile_update_atomic=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+ CFLAGS=$ax_check_save_flags
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result:
$ax_cv_check_cflags___fprofile_update_atomic" >&5
+printf "%s\n" "$ax_cv_check_cflags___fprofile_update_atomic" >&6; }
+if test "x$ax_cv_check_cflags___fprofile_update_atomic" = xyes
+then :
+ PGO_PROF_GEN_FLAG="-fprofile-generate -fprofile-update=atomic"
+else $as_nop
+ PGO_PROF_GEN_FLAG="-fprofile-generate"
+fi
+
PGO_PROF_USE_FLAG="-fprofile-use -fprofile-correction"
LLVM_PROF_MERGER="true"
LLVM_PROF_FILE=""
diff --git a/configure.ac b/configure.ac
index 94776540d1b373..d9acfce793e533 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2137,7 +2137,10 @@ case "$CC_BASENAME" in
fi
;;
*)
- PGO_PROF_GEN_FLAG="-fprofile-generate"
+ AX_CHECK_COMPILE_FLAG(
+ [-fprofile-update=atomic],
+ [PGO_PROF_GEN_FLAG="-fprofile-generate -fprofile-update=atomic"],
+ [PGO_PROF_GEN_FLAG="-fprofile-generate"])
PGO_PROF_USE_FLAG="-fprofile-use -fprofile-correction"
LLVM_PROF_MERGER="true"
LLVM_PROF_FILE=""
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