crashpad/util/stdlib/aligned_allocator.cc
Mark Mentovai f55d18ade6 Add AlignedVector and use it for vector<MEMORY_BASIC_INFORMATION64>
MEMORY_BASIC_INFORMATION64 specifies an alignment of 16, but the
standard allocator used by containers doesn't honor this. Although 16
is the default alignment size used on Windows for x86_64, it's not for
32-bit x86. clang assumed that the alignment of the structure was as
declared, and used an SSE load sequence that required this alignment.

AlignedAllocator is a replacement for std::allocator that allows the
alignment to be specified. AlignedVector is an std::vector<> that uses
AlignedAllocator instead of std::allocator.

BUG=chromium:564691
R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/1498133002 .
2015-12-08 15:38:17 -05:00

79 lines
2.1 KiB
C++

// Copyright 2015 The Crashpad Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "util/stdlib/aligned_allocator.h"
#include <algorithm>
#include "build/build_config.h"
#if defined(OS_POSIX)
#include <stdlib.h>
#elif defined(OS_WIN)
#include <malloc.h>
#include <xutility>
#endif // OS_POSIX
namespace {
// Throws std::bad_alloc() by calling an internal function provided by the C++
// library to do so. This works even if C++ exceptions are disabled, causing
// program termination if uncaught.
void ThrowBadAlloc() {
#if defined(OS_POSIX)
// This works with both libc++ and libstdc++.
std::__throw_bad_alloc();
#elif defined(OS_WIN)
std::_Xbad_alloc();
#endif // OS_POSIX
}
} // namespace
namespace crashpad {
namespace internal {
void* AlignedAllocate(size_t alignment, size_t size) {
#if defined(OS_POSIX)
// posix_memalign() requires that alignment be at least sizeof(void*), so the
// power-of-2 check needs to happen before potentially changing the alignment.
if (alignment == 0 || alignment & (alignment - 1)) {
ThrowBadAlloc();
}
void* pointer;
if (posix_memalign(&pointer, std::max(alignment, sizeof(void*)), size) != 0) {
ThrowBadAlloc();
}
#elif defined(OS_WIN)
void* pointer = _aligned_malloc(size, alignment);
if (pointer == nullptr) {
ThrowBadAlloc();
}
#endif // OS_POSIX
return pointer;
}
void AlignedFree(void* pointer) {
#if defined(OS_POSIX)
free(pointer);
#elif defined(OS_WIN)
_aligned_free(pointer);
#endif // OS_POSIX
}
} // namespace internal
} // namespace crashpad