base/memory/aligned_memory.cc

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/memory/aligned_memory.h"

#include <bit>

#include "base/check.h"
#include "base/check_op.h"
#include "base/logging.h"
#include "build/build_config.h"

#if BUILDFLAG(IS_ANDROID)
#include <malloc.h>
#endif

namespace base {

void* AlignedAlloc(size_t size, size_t alignment) {
  DCHECK_GT(size, 0U);
  DCHECK(std::has_single_bit(alignment));
  DCHECK_EQ(alignment % sizeof(void*), 0U);
  void* ptr = nullptr;
#if defined(COMPILER_MSVC)
  ptr = _aligned_malloc(size, alignment);
#elif BUILDFLAG(IS_ANDROID)
  // Android technically supports posix_memalign(), but does not expose it in
  // the current version of the library headers used by Chromium.  Luckily,
  // memalign() on Android returns pointers which can safely be used with
  // free(), so we can use it instead.  Issue filed to document this:
  // http://code.google.com/p/android/issues/detail?id=35391
  ptr = memalign(alignment, size);
#else
  int ret = posix_memalign(&ptr, alignment, size);
  if (ret != 0) {
    DLOG(ERROR) << "posix_memalign() returned with error " << ret;
    ptr = nullptr;
  }
#endif

  // Since aligned allocations may fail for non-memory related reasons, force a
  // crash if we encounter a failed allocation; maintaining consistent behavior
  // with a normal allocation failure in Chrome.
  CHECK(ptr) << "If you crashed here, your aligned allocation is incorrect: "
             << "size=" << size << ", alignment=" << alignment;

  // Sanity check alignment just to be safe.
  DCHECK(IsAligned(ptr, alignment));
  return ptr;
}

}  // namespace base