fc8dc48020
git-subtree-dir: third_party/abseil_cpp git-subtree-mainline:ffb2ae54begit-subtree-split:768eb2ca28
158 lines
4.8 KiB
C++
158 lines
4.8 KiB
C++
//
|
|
// Copyright 2017 The Abseil Authors.
|
|
//
|
|
// 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
|
|
//
|
|
// https://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.
|
|
//
|
|
|
|
#ifndef ABSL_BASE_INTERNAL_UNALIGNED_ACCESS_H_
|
|
#define ABSL_BASE_INTERNAL_UNALIGNED_ACCESS_H_
|
|
|
|
#include <string.h>
|
|
|
|
#include <cstdint>
|
|
|
|
#include "absl/base/attributes.h"
|
|
#include "absl/base/config.h"
|
|
|
|
// unaligned APIs
|
|
|
|
// Portable handling of unaligned loads, stores, and copies.
|
|
|
|
// The unaligned API is C++ only. The declarations use C++ features
|
|
// (namespaces, inline) which are absent or incompatible in C.
|
|
#if defined(__cplusplus)
|
|
|
|
#if defined(ADDRESS_SANITIZER) || defined(THREAD_SANITIZER) ||\
|
|
defined(MEMORY_SANITIZER)
|
|
// Consider we have an unaligned load/store of 4 bytes from address 0x...05.
|
|
// AddressSanitizer will treat it as a 3-byte access to the range 05:07 and
|
|
// will miss a bug if 08 is the first unaddressable byte.
|
|
// ThreadSanitizer will also treat this as a 3-byte access to 05:07 and will
|
|
// miss a race between this access and some other accesses to 08.
|
|
// MemorySanitizer will correctly propagate the shadow on unaligned stores
|
|
// and correctly report bugs on unaligned loads, but it may not properly
|
|
// update and report the origin of the uninitialized memory.
|
|
// For all three tools, replacing an unaligned access with a tool-specific
|
|
// callback solves the problem.
|
|
|
|
// Make sure uint16_t/uint32_t/uint64_t are defined.
|
|
#include <stdint.h>
|
|
|
|
extern "C" {
|
|
uint16_t __sanitizer_unaligned_load16(const void *p);
|
|
uint32_t __sanitizer_unaligned_load32(const void *p);
|
|
uint64_t __sanitizer_unaligned_load64(const void *p);
|
|
void __sanitizer_unaligned_store16(void *p, uint16_t v);
|
|
void __sanitizer_unaligned_store32(void *p, uint32_t v);
|
|
void __sanitizer_unaligned_store64(void *p, uint64_t v);
|
|
} // extern "C"
|
|
|
|
namespace absl {
|
|
ABSL_NAMESPACE_BEGIN
|
|
namespace base_internal {
|
|
|
|
inline uint16_t UnalignedLoad16(const void *p) {
|
|
return __sanitizer_unaligned_load16(p);
|
|
}
|
|
|
|
inline uint32_t UnalignedLoad32(const void *p) {
|
|
return __sanitizer_unaligned_load32(p);
|
|
}
|
|
|
|
inline uint64_t UnalignedLoad64(const void *p) {
|
|
return __sanitizer_unaligned_load64(p);
|
|
}
|
|
|
|
inline void UnalignedStore16(void *p, uint16_t v) {
|
|
__sanitizer_unaligned_store16(p, v);
|
|
}
|
|
|
|
inline void UnalignedStore32(void *p, uint32_t v) {
|
|
__sanitizer_unaligned_store32(p, v);
|
|
}
|
|
|
|
inline void UnalignedStore64(void *p, uint64_t v) {
|
|
__sanitizer_unaligned_store64(p, v);
|
|
}
|
|
|
|
} // namespace base_internal
|
|
ABSL_NAMESPACE_END
|
|
} // namespace absl
|
|
|
|
#define ABSL_INTERNAL_UNALIGNED_LOAD16(_p) \
|
|
(absl::base_internal::UnalignedLoad16(_p))
|
|
#define ABSL_INTERNAL_UNALIGNED_LOAD32(_p) \
|
|
(absl::base_internal::UnalignedLoad32(_p))
|
|
#define ABSL_INTERNAL_UNALIGNED_LOAD64(_p) \
|
|
(absl::base_internal::UnalignedLoad64(_p))
|
|
|
|
#define ABSL_INTERNAL_UNALIGNED_STORE16(_p, _val) \
|
|
(absl::base_internal::UnalignedStore16(_p, _val))
|
|
#define ABSL_INTERNAL_UNALIGNED_STORE32(_p, _val) \
|
|
(absl::base_internal::UnalignedStore32(_p, _val))
|
|
#define ABSL_INTERNAL_UNALIGNED_STORE64(_p, _val) \
|
|
(absl::base_internal::UnalignedStore64(_p, _val))
|
|
|
|
#else
|
|
|
|
namespace absl {
|
|
ABSL_NAMESPACE_BEGIN
|
|
namespace base_internal {
|
|
|
|
inline uint16_t UnalignedLoad16(const void *p) {
|
|
uint16_t t;
|
|
memcpy(&t, p, sizeof t);
|
|
return t;
|
|
}
|
|
|
|
inline uint32_t UnalignedLoad32(const void *p) {
|
|
uint32_t t;
|
|
memcpy(&t, p, sizeof t);
|
|
return t;
|
|
}
|
|
|
|
inline uint64_t UnalignedLoad64(const void *p) {
|
|
uint64_t t;
|
|
memcpy(&t, p, sizeof t);
|
|
return t;
|
|
}
|
|
|
|
inline void UnalignedStore16(void *p, uint16_t v) { memcpy(p, &v, sizeof v); }
|
|
|
|
inline void UnalignedStore32(void *p, uint32_t v) { memcpy(p, &v, sizeof v); }
|
|
|
|
inline void UnalignedStore64(void *p, uint64_t v) { memcpy(p, &v, sizeof v); }
|
|
|
|
} // namespace base_internal
|
|
ABSL_NAMESPACE_END
|
|
} // namespace absl
|
|
|
|
#define ABSL_INTERNAL_UNALIGNED_LOAD16(_p) \
|
|
(absl::base_internal::UnalignedLoad16(_p))
|
|
#define ABSL_INTERNAL_UNALIGNED_LOAD32(_p) \
|
|
(absl::base_internal::UnalignedLoad32(_p))
|
|
#define ABSL_INTERNAL_UNALIGNED_LOAD64(_p) \
|
|
(absl::base_internal::UnalignedLoad64(_p))
|
|
|
|
#define ABSL_INTERNAL_UNALIGNED_STORE16(_p, _val) \
|
|
(absl::base_internal::UnalignedStore16(_p, _val))
|
|
#define ABSL_INTERNAL_UNALIGNED_STORE32(_p, _val) \
|
|
(absl::base_internal::UnalignedStore32(_p, _val))
|
|
#define ABSL_INTERNAL_UNALIGNED_STORE64(_p, _val) \
|
|
(absl::base_internal::UnalignedStore64(_p, _val))
|
|
|
|
#endif
|
|
|
|
#endif // defined(__cplusplus), end of unaligned API
|
|
|
|
#endif // ABSL_BASE_INTERNAL_UNALIGNED_ACCESS_H_
|