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gh-148284: Block inlining of gigantic functions in ceval.c for clang 22 #148334

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Merged
Fidget-Spinner merged 6 commits into from
Apr 10, 2026
Merged

gh-148284: Block inlining of gigantic functions in ceval.c for clang 22 #148334

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1a85b01
Block inlining of gigantic functions
Fidget-Spinner Apr 10, 2026
291f142
📜🤖 Added by blurb_it.
blurb-it[bot] Apr 10, 2026
4b79670
remove unused function
Fidget-Spinner Apr 10, 2026
a95c401
Address Victor review
Fidget-Spinner Apr 10, 2026
91352a9
Delete 2026-04-10-09-21-40.gh-issue-148284.6xMH49.rst
Fidget-Spinner Apr 10, 2026
0ddb3ec
📜🤖 Added by blurb_it.
blurb-it[bot] Apr 10, 2026
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Address Victor review 
Co-Authored-By: Victor Stinner <vstinner@python.org>
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@Fidget-Spinner @vstinner
Fidget-Spinner and vstinner committed Apr 10, 2026
commit a95c401df5b884633b9f1ebbf344cc1778b099fe
6 changes: 6 additions & 0 deletions Doc/using/configure.rst
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Expand Up @@ -1574,6 +1574,12 @@ Compiler flags

.. versionadded:: 3.7

.. envvar:: CFLAGS_CEVAL

Flags used to compile ``Python/ceval.c``.

.. versionadded:: 3.14.5
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.. envvar:: CCSHARED

Compiler flags used to build a shared library.
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18 changes: 9 additions & 9 deletions configure
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18 changes: 9 additions & 9 deletions configure.ac
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Expand Up @@ -7374,10 +7374,10 @@ fi
AC_MSG_CHECKING([if we need to manually block large inlining in ceval.c])
AC_RUN_IFELSE([AC_LANG_SOURCE([[
int main(void) {
// See gh-148284:
// Clang 22 seems to have interactions with inlining and the stackref buffer
// which cause 40kB of stack usage on x86-64 in buggy versions of _PyEval_EvalFrameDefault
// in computed goto interpreter. The normal usage seen is normally 1-2kB.
// See gh-148284: Clang 22 seems to have interactions with inlining
// and the stackref buffer which cause 40 kB of stack usage on x86-64
// in buggy versions of _PyEval_EvalFrameDefault() in computed goto
// interpreter. The normal usage seen is normally 1-2 kB.
#if defined(__clang__) && (__clang_major__ == 22)
return 1;
#else
Expand All @@ -7391,11 +7391,11 @@ int main(void) {
AC_MSG_RESULT([$block_huge_inlining_in_ceval])

if test "$block_huge_inlining_in_ceval" = yes && test "$ac_cv_computed_gotos" = yes; then
// This number should be tuned to follow the C stack consumption
// in _PyEval_EvalFrameDefault on computed goto interpreter.
CFLAGS_CEVAL="-finline-max-stacksize=512"
else
CFLAGS_CEVAL=""
# gh-148284: Suppress inlining of functions whose stack size exceeds
# 512 bytes. This number should be tuned to follow the C stack
# consumption in _PyEval_EvalFrameDefault() on computed goto
# interpreter.
CFLAGS_CEVAL="$CFLAGS_CEVAL -finline-max-stacksize=512"
fi
AC_SUBST([CFLAGS_CEVAL])

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