glibc/sysdeps/generic/tst-stack-align.h
H.J. Lu 79aec84102 Properly check stack alignment [BZ #27901]
1. Replace

if ((((uintptr_t) &_d) & (__alignof (double) - 1)) != 0)

which may be optimized out by compiler, with

int
__attribute__ ((weak, noclone, noinline))
is_aligned (void *p, int align)
{
  return (((uintptr_t) p) & (align - 1)) != 0;
}

2. Add TEST_STACK_ALIGN_INIT to TEST_STACK_ALIGN.
3. Add a common TEST_STACK_ALIGN_INIT to check 16-byte stack alignment
for both i386 and x86-64.
4. Update powerpc to use TEST_STACK_ALIGN_INIT.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-05-24 07:42:12 -07:00

47 lines
1.6 KiB
C

/* Check stack alignment. Generic version.
Copyright (C) 2003-2021 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
<https://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <stdint.h>
int
__attribute__ ((weak, noclone, noinline))
is_aligned (void *p, int align)
{
return (((uintptr_t) p) & (align - 1)) != 0;
}
#ifndef TEST_STACK_ALIGN_INIT
# define TEST_STACK_ALIGN_INIT() 0
#endif
#define TEST_STACK_ALIGN() \
({ \
double _d = 12.0; \
long double _ld = 15.0; \
int _ret = TEST_STACK_ALIGN_INIT (); \
\
printf ("double: %g %p %zu\n", _d, &_d, __alignof (double)); \
_ret += is_aligned (&_d, __alignof (double)); \
\
printf ("ldouble: %Lg %p %zu\n", _ld, &_ld, \
__alignof (long double)); \
_ret += is_aligned (&_ld, __alignof (long double)); \
_ret; \
})