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i386: Increase MALLOC_ALIGNMENT to 16 [BZ #21120]

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GCC 7 changed the definition of max_align_t on i386:

https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=9b5c49ef97e63cc63f1ffa13baf771368105ebe2

As a result, glibc malloc no longer returns memory blocks which are as
aligned as max_align_t requires.

This causes malloc/tst-malloc-thread-fail to fail with an error like this
one:

error: allocation function 0, size 144 not aligned to 16

This patch moves the MALLOC_ALIGNMENT definition to <malloc-alignment.h>
and increases the malloc alignment to 16 for i386.

	[BZ #21120]
	* malloc/malloc-internal.h (MALLOC_ALIGNMENT): Moved to ...
	* sysdeps/generic/malloc-alignment.h: Here.  New file.
	* sysdeps/i386/malloc-alignment.h: Likewise.
	* sysdeps/generic/malloc-machine.h: Include <malloc-alignment.h>.
This commit is contained in:
H.J. Lu
2017-06-30 09:11:08 -07:00
parent a9270e673d
commit 4e61a6be44
5 changed files with 64 additions and 10 deletions
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31
sysdeps/generic/malloc-alignment.h Normal file
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@ -0,0 +1,31 @@
/* Define MALLOC_ALIGNMENT for malloc. Generic version.
Copyright (C) 2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _GENERIC_MALLOC_ALIGNMENT_H
#define _GENERIC_MALLOC_ALIGNMENT_H
/* MALLOC_ALIGNMENT is the minimum alignment for malloc'ed chunks. It
must be a power of two at least 2 * SIZE_SZ, even on machines for
which smaller alignments would suffice. It may be defined as larger
than this though. Note however that code and data structures are
optimized for the case of 8-byte alignment. */
#define MALLOC_ALIGNMENT (2 * SIZE_SZ < __alignof__ (long double) \
? __alignof__ (long double) : 2 * SIZE_SZ)
#endif /* !defined(_GENERIC_MALLOC_ALIGNMENT_H) */