gh-89536: Use ThinLTO policy if possible (gh-96766)

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Dong-hee Na 2022-09-16 19:40:05 +09:00 committed by GitHub
parent 16c33a9676
commit e47b96c44f
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5 changed files with 99 additions and 6 deletions

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@ -232,6 +232,9 @@ also be used to improve performance.
.. versionadded:: 3.11
To use ThinLTO feature, use ``--with-lto=thin`` on Clang.
.. versionchanged:: 3.12
Use ThinLTO as the default optimization policy on Clang if the compiler accepts the flag.
.. cmdoption:: --enable-bolt
Enable usage of the `BOLT post-link binary optimizer

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@ -453,6 +453,10 @@ Build Changes
``va_start()`` is no longer called with a single parameter.
(Contributed by Kumar Aditya in :gh:`93207`.)
* CPython now uses the ThinLTO option as the default link time optimization policy
if the Clang compiler accepts the flag.
(Contributed by Dong-hee Na in :gh:`89536`.)
C API Changes
=============

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@ -0,0 +1,2 @@
CPython now uses the ThinLTO option as the default policy if the Clang
compiler accepts the flag. Patch by Dong-hee Na.

82
configure generated vendored
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@ -7837,8 +7837,49 @@ $as_echo "$as_me: llvm-ar found via xcrun: ${LLVM_AR}" >&6;}
# Any changes made here should be reflected in the GCC+Darwin case below
if test $Py_LTO_POLICY = default
then
LTOFLAGS="-flto -Wl,-export_dynamic -Wl,-object_path_lto,\"\$@\".lto"
LTOCFLAGS="-flto"
# Check that ThinLTO is accepted.
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether C compiler accepts -flto=thin" >&5
$as_echo_n "checking whether C compiler accepts -flto=thin... " >&6; }
if ${ax_cv_check_cflags___flto_thin+:} false; then :
$as_echo_n "(cached) " >&6
else
ax_check_save_flags=$CFLAGS
CFLAGS="$CFLAGS -flto=thin"
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int
main ()
{
;
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
ax_cv_check_cflags___flto_thin=yes
else
ax_cv_check_cflags___flto_thin=no
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
CFLAGS=$ax_check_save_flags
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_check_cflags___flto_thin" >&5
$as_echo "$ax_cv_check_cflags___flto_thin" >&6; }
if test "x$ax_cv_check_cflags___flto_thin" = xyes; then :
LTOFLAGS="-flto=thin -Wl,-export_dynamic -Wl,-object_path_lto,\"\$@\".lto"
LTOCFLAGS="-flto=thin"
else
LTOFLAGS="-flto -Wl,-export_dynamic -Wl,-object_path_lto,\"\$@\".lto"
LTOCFLAGS="-flto"
fi
else
LTOFLAGS="-flto=${Py_LTO_POLICY} -Wl,-export_dynamic -Wl,-object_path_lto,\"\$@\".lto"
LTOCFLAGS="-flto=${Py_LTO_POLICY}"
@ -7847,7 +7888,42 @@ $as_echo "$as_me: llvm-ar found via xcrun: ${LLVM_AR}" >&6;}
*)
if test $Py_LTO_POLICY = default
then
LTOFLAGS="-flto"
# Check that ThinLTO is accepted
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether C compiler accepts -flto=thin" >&5
$as_echo_n "checking whether C compiler accepts -flto=thin... " >&6; }
if ${ax_cv_check_cflags___flto_thin+:} false; then :
$as_echo_n "(cached) " >&6
else
ax_check_save_flags=$CFLAGS
CFLAGS="$CFLAGS -flto=thin"
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int
main ()
{
;
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
ax_cv_check_cflags___flto_thin=yes
else
ax_cv_check_cflags___flto_thin=no
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
CFLAGS=$ax_check_save_flags
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_check_cflags___flto_thin" >&5
$as_echo "$ax_cv_check_cflags___flto_thin" >&6; }
if test "x$ax_cv_check_cflags___flto_thin" = xyes; then :
LTOFLAGS="-flto=thin"
else
LTOFLAGS="-flto"
fi
else
LTOFLAGS="-flto=${Py_LTO_POLICY}"
fi

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@ -1863,8 +1863,15 @@ if test "$Py_LTO" = 'true' ; then
# Any changes made here should be reflected in the GCC+Darwin case below
if test $Py_LTO_POLICY = default
then
LTOFLAGS="-flto -Wl,-export_dynamic -Wl,-object_path_lto,\"\$@\".lto"
LTOCFLAGS="-flto"
# Check that ThinLTO is accepted.
AX_CHECK_COMPILE_FLAG([-flto=thin],[
LTOFLAGS="-flto=thin -Wl,-export_dynamic -Wl,-object_path_lto,\"\$@\".lto"
LTOCFLAGS="-flto=thin"
],[
LTOFLAGS="-flto -Wl,-export_dynamic -Wl,-object_path_lto,\"\$@\".lto"
LTOCFLAGS="-flto"
]
)
else
LTOFLAGS="-flto=${Py_LTO_POLICY} -Wl,-export_dynamic -Wl,-object_path_lto,\"\$@\".lto"
LTOCFLAGS="-flto=${Py_LTO_POLICY}"
@ -1873,7 +1880,8 @@ if test "$Py_LTO" = 'true' ; then
*)
if test $Py_LTO_POLICY = default
then
LTOFLAGS="-flto"
# Check that ThinLTO is accepted
AX_CHECK_COMPILE_FLAG([-flto=thin],[LTOFLAGS="-flto=thin"],[LTOFLAGS="-flto"])
else
LTOFLAGS="-flto=${Py_LTO_POLICY}"
fi