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bpo-36618: Don't add -fmax-type-align=8 flag for clang (GH-13320) 

Python 3.8 now respects the x86-64 ABI: memory allocations are
aligned on 16 bytes. The clang flag was only used as a temporary
workaround.
This commit is contained in:
Victor Stinner 2019-05-14 19:29:53 +02:00 committed by GitHub
parent c1f5667be1
commit d97adfb409
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2 changed files with 0 additions and 40 deletions
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20
configure vendored
View File

@ -6905,26 +6905,6 @@ then
esac esac
fi fi
if test -n "${cc_is_clang}"
then
# bpo-36618: Add -fmax-type-align=8 to CFLAGS when clang compiler is
# detected. The pymalloc memory allocator aligns memory on 8 bytes. On
# x86-64, clang expects alignment on 16 bytes by default and so uses MOVAPS
# instruction which can lead to segmentation fault. Instruct clang that
# Python is limited to alignemnt on 8 bytes to use MOVUPS instruction
# instead: slower but don't trigger a SIGSEGV if the memory is not aligned
# on 16 bytes.
#
# Sadly, the flag must be added to CFLAGS and not just CFLAGS_NODIST,
# since third party C extensions can have the same issue.
#
# Check if -fmax-type-align flag is supported (it's not supported by old
# clang versions):
if "$CC" -v --help 2>/dev/null |grep -- -fmax-type-align > /dev/null; then
CFLAGS="$CFLAGS -fmax-type-align=8"
fi
fi

20
configure.ac
View File

@ -1543,26 +1543,6 @@ then
esac esac
fi fi
if test -n "${cc_is_clang}"
then
# bpo-36618: Add -fmax-type-align=8 to CFLAGS when clang compiler is
# detected. The pymalloc memory allocator aligns memory on 8 bytes. On
# x86-64, clang expects alignment on 16 bytes by default and so uses MOVAPS
# instruction which can lead to segmentation fault. Instruct clang that
# Python is limited to alignemnt on 8 bytes to use MOVUPS instruction
# instead: slower but don't trigger a SIGSEGV if the memory is not aligned
# on 16 bytes.
#
# Sadly, the flag must be added to CFLAGS and not just CFLAGS_NODIST,
# since third party C extensions can have the same issue.
#
# Check if -fmax-type-align flag is supported (it's not supported by old
# clang versions):
if "$CC" -v --help 2>/dev/null |grep -- -fmax-type-align > /dev/null; then
CFLAGS="$CFLAGS -fmax-type-align=8"
fi
fi
AC_SUBST(BASECFLAGS) AC_SUBST(BASECFLAGS)
AC_SUBST(CFLAGS_NODIST) AC_SUBST(CFLAGS_NODIST)
AC_SUBST(LDFLAGS_NODIST) AC_SUBST(LDFLAGS_NODIST)