mirror of
https://sourceware.org/git/glibc.git
synced 2025-11-03 20:53:13 +03:00
4e61a6be44
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>.
95 lines
3.6 KiB
C
95 lines
3.6 KiB
C
/* Internal declarations for malloc, for use within libc.
|
|
Copyright (C) 2016-2017 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; see the file COPYING.LIB. If
|
|
not, see <http://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef _MALLOC_INTERNAL_H
|
|
#define _MALLOC_INTERNAL_H
|
|
|
|
#include <malloc-machine.h>
|
|
#include <malloc-sysdep.h>
|
|
|
|
/* INTERNAL_SIZE_T is the word-size used for internal bookkeeping of
|
|
chunk sizes.
|
|
|
|
The default version is the same as size_t.
|
|
|
|
While not strictly necessary, it is best to define this as an
|
|
unsigned type, even if size_t is a signed type. This may avoid some
|
|
artificial size limitations on some systems.
|
|
|
|
On a 64-bit machine, you may be able to reduce malloc overhead by
|
|
defining INTERNAL_SIZE_T to be a 32 bit `unsigned int' at the
|
|
expense of not being able to handle more than 2^32 of malloced
|
|
space. If this limitation is acceptable, you are encouraged to set
|
|
this unless you are on a platform requiring 16byte alignments. In
|
|
this case the alignment requirements turn out to negate any
|
|
potential advantages of decreasing size_t word size.
|
|
|
|
Implementors: Beware of the possible combinations of:
|
|
- INTERNAL_SIZE_T might be signed or unsigned, might be 32 or 64 bits,
|
|
and might be the same width as int or as long
|
|
- size_t might have different width and signedness as INTERNAL_SIZE_T
|
|
- int and long might be 32 or 64 bits, and might be the same width
|
|
|
|
To deal with this, most comparisons and difference computations
|
|
among INTERNAL_SIZE_Ts should cast them to unsigned long, being
|
|
aware of the fact that casting an unsigned int to a wider long does
|
|
not sign-extend. (This also makes checking for negative numbers
|
|
awkward.) Some of these casts result in harmless compiler warnings
|
|
on some systems. */
|
|
#ifndef INTERNAL_SIZE_T
|
|
# define INTERNAL_SIZE_T size_t
|
|
#endif
|
|
|
|
/* The corresponding word size. */
|
|
#define SIZE_SZ (sizeof (INTERNAL_SIZE_T))
|
|
|
|
/* The corresponding bit mask value. */
|
|
#define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1)
|
|
|
|
|
|
/* Called in the parent process before a fork. */
|
|
void __malloc_fork_lock_parent (void) internal_function attribute_hidden;
|
|
|
|
/* Called in the parent process after a fork. */
|
|
void __malloc_fork_unlock_parent (void) internal_function attribute_hidden;
|
|
|
|
/* Called in the child process after a fork. */
|
|
void __malloc_fork_unlock_child (void) internal_function attribute_hidden;
|
|
|
|
/* Set *RESULT to LEFT * RIGHT. Return true if the multiplication
|
|
overflowed. */
|
|
static inline bool
|
|
check_mul_overflow_size_t (size_t left, size_t right, size_t *result)
|
|
{
|
|
#if __GNUC__ >= 5
|
|
return __builtin_mul_overflow (left, right, result);
|
|
#else
|
|
/* size_t is unsigned so the behavior on overflow is defined. */
|
|
*result = left * right;
|
|
size_t half_size_t = ((size_t) 1) << (8 * sizeof (size_t) / 2);
|
|
if (__glibc_unlikely ((left | right) >= half_size_t))
|
|
{
|
|
if (__glibc_unlikely (right != 0 && *result / right != left))
|
|
return true;
|
|
}
|
|
return false;
|
|
#endif
|
|
}
|
|
|
|
#endif /* _MALLOC_INTERNAL_H */
|