1  /* aligned memory allocation
       2  
       3     Copyright 2022-2023 Free Software Foundation, Inc.
       4  
       5     This program is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU General Public License as published by
       7     the Free Software Foundation, either version 3 of the License, or
       8     (at your option) any later version.
       9  
      10     This program is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13     GNU General Public License for more details.
      14  
      15     You should have received a copy of the GNU General Public License
      16     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      17  
      18  /* Written by Paul Eggert.  */
      19  
      20  #ifndef ALIGNALLOC_H_
      21  #define ALIGNALLOC_H_
      22  
      23  /* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE, _GL_ATTRIBUTE_ALLOC_SIZE,
      24     _GL_ATTRIBUTE_MALLOC, _GL_ATTRIBUTE_RETURNS_NONNULL, HAVE_POSIX_MEMALIGN.  */
      25  #if !_GL_CONFIG_H_INCLUDED
      26   #error "Please include config.h first."
      27  #endif
      28  
      29  #include <errno.h>
      30  #include <stdlib.h>
      31  #include "idx.h"
      32  
      33  _GL_INLINE_HEADER_BEGIN
      34  #ifndef ALIGNALLOC_INLINE
      35  # define ALIGNALLOC_INLINE _GL_INLINE
      36  #endif
      37  
      38  /* Whether aligned_alloc supports any power-of-two alignment,
      39     returns a nonnull pointer for size-zero allocations,
      40     and sets errno on failure.  */
      41  #if 2 < __GLIBC__ + (16 <= __GLIBC_MINOR__)
      42  # define ALIGNALLOC_VIA_ALIGNED_ALLOC 1
      43  #else
      44  # define ALIGNALLOC_VIA_ALIGNED_ALLOC 0
      45  #endif
      46  
      47  /* Work around AddressSanitizer bug.
      48     https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104262
      49     https://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20220124/1001910.html
      50     */
      51  #ifdef __SANITIZE_ADDRESS__
      52  # undef ALIGNALLOC_VIA_ALIGNED_ALLOC
      53  # define ALIGNALLOC_VIA_ALIGNED_ALLOC 0
      54  #endif
      55  #ifdef __has_feature
      56  # if __has_feature (address_sanitizer)
      57  #  undef ALIGNALLOC_VIA_ALIGNED_ALLOC
      58  #  define ALIGNALLOC_VIA_ALIGNED_ALLOC 0
      59  # endif
      60  #endif
      61  
      62  #if ALIGNALLOC_VIA_ALIGNED_ALLOC || HAVE_POSIX_MEMALIGN
      63  
      64  /* Free storage allocated via alignalloc.  Do nothing if PTR is null.  */
      65  
      66  ALIGNALLOC_INLINE void
      67  alignfree (void *ptr)
      68  {
      69    free (ptr);
      70  }
      71  
      72  /* Return an ALIGNMENT-aligned pointer to new storage of size SIZE,
      73     or a null pointer (setting errno) if memory is exhausted.
      74     ALIGNMENT must be a power of two.
      75     If SIZE is zero, on success return a unique pointer each time.
      76     To free storage later, call alignfree.  */
      77  
      78  ALIGNALLOC_INLINE
      79  _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2))
      80  /* _GL_ATTRIBUTE_DEALLOC (alignfree, 1) */
      81  void *
      82  alignalloc (idx_t alignment, idx_t size)
      83  {
      84    if ((size_t) -1 < alignment)
      85      alignment = (size_t) -1;
      86    if ((size_t) -1 < size)
      87      size = (size_t) -1;
      88  
      89  # if ALIGNALLOC_VIA_ALIGNED_ALLOC
      90    return aligned_alloc (alignment, size);
      91  # else
      92    void *ptr = NULL;
      93    if (alignment < sizeof (void *))
      94      alignment = sizeof (void *);
      95    errno = posix_memalign (&ptr, alignment, size | !size);
      96    return ptr;
      97  # endif
      98  }
      99  
     100  #else /* ! (ALIGNALLOC_VIA_ALIGNED_ALLOC || HAVE_POSIX_MEMALIGN) */
     101  
     102  void alignfree (void *);
     103  void *alignalloc (idx_t, idx_t)
     104    _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2))
     105    _GL_ATTRIBUTE_DEALLOC (alignfree, 1);
     106  
     107  #endif
     108  
     109  /* Like alignalloc, but die instead of returning a null pointer.  */
     110  void *xalignalloc (idx_t, idx_t)
     111    _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2))
     112    _GL_ATTRIBUTE_RETURNS_NONNULL /* _GL_ATTRIBUTE_DEALLOC (alignfree, 1) */;
     113  
     114  _GL_INLINE_HEADER_END
     115  
     116  #endif /* !ALIGNALLOC_H_ */