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gh-145801: Use gcc -fprofile-update=atomic for PGO builds (#145802)

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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.
This commit is contained in:
Victor Stinner 2026-03-12 23:48:51 +01:00 • committed by GitHub
parent f105265538
commit 08a018ebe0
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3 changed files with 49 additions and 2 deletions
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4
Misc/NEWS.d/next/Build/2026-03-11-11-58-42.gh-issue-145801.iCXa3v.rst Normal file
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@ -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.

42
configure generated vendored
View file

@ -9083,7 +9083,47 @@ case "$ac_cv_cc_name" in
fi
;;
gcc)
PGO_PROF_GEN_FLAG="-fprofile-generate"
{ printf "%s\n" "$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 ${ax_cv_check_cflags___fprofile_update_atomic+y}
then :
printf %s "(cached) " >&6
else case e in #(
e)
ax_check_save_flags=$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 "$LINENO"
then :
ax_cv_check_cflags___fprofile_update_atomic=yes
else case e in #(
e) ax_cv_check_cflags___fprofile_update_atomic=no ;;
esac
fi
rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
CFLAGS=$ax_check_save_flags ;;
esac
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 case e in #(
e) PGO_PROF_GEN_FLAG="-fprofile-generate" ;;
esac
fi
PGO_PROF_USE_FLAG="-fprofile-use -fprofile-correction"
LLVM_PROF_MERGER="true"
LLVM_PROF_FILE=""

5
configure.ac
View file

@ -2084,7 +2084,10 @@ case "$ac_cv_cc_name" in
fi
;;
gcc)
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=""