gcc/libsanitizer/sanitizer_common/sanitizer_allocator.cc

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//===-- sanitizer_allocator.cc --------------------------------------------===//
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is shared between AddressSanitizer and ThreadSanitizer
// run-time libraries.
// This allocator is used inside run-times.
//===----------------------------------------------------------------------===//
#include "sanitizer_allocator.h"
#include "sanitizer_allocator_internal.h"
#include "sanitizer_atomic.h"
#include "sanitizer_common.h"
namespace __sanitizer {
// ThreadSanitizer for Go uses libc malloc/free.
#if SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
# if SANITIZER_LINUX && !SANITIZER_ANDROID
extern "C" void *__libc_malloc(uptr size);
# if !SANITIZER_GO
extern "C" void *__libc_memalign(uptr alignment, uptr size);
# endif
extern "C" void *__libc_realloc(void *ptr, uptr size);
extern "C" void __libc_free(void *ptr);
# else
# include <stdlib.h>
# define __libc_malloc malloc
# if !SANITIZER_GO
static void *__libc_memalign(uptr alignment, uptr size) {
void *p;
uptr error = posix_memalign(&p, alignment, size);
if (error) return nullptr;
return p;
}
# endif
# define __libc_realloc realloc
# define __libc_free free
# endif
static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
uptr alignment) {
(void)cache;
#if !SANITIZER_GO
if (alignment == 0)
return __libc_malloc(size);
else
return __libc_memalign(alignment, size);
#else
// Windows does not provide __libc_memalign/posix_memalign. It provides
// __aligned_malloc, but the allocated blocks can't be passed to free,
// they need to be passed to __aligned_free. InternalAlloc interface does
// not account for such requirement. Alignemnt does not seem to be used
// anywhere in runtime, so just call __libc_malloc for now.
DCHECK_EQ(alignment, 0);
return __libc_malloc(size);
#endif
}
static void *RawInternalRealloc(void *ptr, uptr size,
InternalAllocatorCache *cache) {
(void)cache;
return __libc_realloc(ptr, size);
}
static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
(void)cache;
__libc_free(ptr);
}
InternalAllocator *internal_allocator() {
return 0;
}
#else // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
static atomic_uint8_t internal_allocator_initialized;
static StaticSpinMutex internal_alloc_init_mu;
static InternalAllocatorCache internal_allocator_cache;
static StaticSpinMutex internal_allocator_cache_mu;
InternalAllocator *internal_allocator() {
InternalAllocator *internal_allocator_instance =
reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
if (atomic_load(&internal_allocator_initialized, memory_order_acquire) == 0) {
SpinMutexLock l(&internal_alloc_init_mu);
if (atomic_load(&internal_allocator_initialized, memory_order_relaxed) ==
0) {
internal_allocator_instance->Init(/* may_return_null*/ false);
atomic_store(&internal_allocator_initialized, 1, memory_order_release);
}
}
return internal_allocator_instance;
}
static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
uptr alignment) {
if (alignment == 0) alignment = 8;
if (cache == 0) {
SpinMutexLock l(&internal_allocator_cache_mu);
return internal_allocator()->Allocate(&internal_allocator_cache, size,
alignment, false);
}
return internal_allocator()->Allocate(cache, size, alignment, false);
}
static void *RawInternalRealloc(void *ptr, uptr size,
InternalAllocatorCache *cache) {
uptr alignment = 8;
if (cache == 0) {
SpinMutexLock l(&internal_allocator_cache_mu);
return internal_allocator()->Reallocate(&internal_allocator_cache, ptr,
size, alignment);
}
return internal_allocator()->Reallocate(cache, ptr, size, alignment);
}
static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
if (!cache) {
SpinMutexLock l(&internal_allocator_cache_mu);
return internal_allocator()->Deallocate(&internal_allocator_cache, ptr);
}
internal_allocator()->Deallocate(cache, ptr);
}
#endif // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
if (size + sizeof(u64) < size)
return nullptr;
void *p = RawInternalAlloc(size + sizeof(u64), cache, alignment);
if (!p)
return nullptr;
((u64*)p)[0] = kBlockMagic;
return (char*)p + sizeof(u64);
}
void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
if (!addr)
return InternalAlloc(size, cache);
if (size + sizeof(u64) < size)
return nullptr;
addr = (char*)addr - sizeof(u64);
size = size + sizeof(u64);
CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
void *p = RawInternalRealloc(addr, size, cache);
if (!p)
return nullptr;
return (char*)p + sizeof(u64);
}
void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
if (CallocShouldReturnNullDueToOverflow(count, size))
return internal_allocator()->ReturnNullOrDieOnBadRequest();
void *p = InternalAlloc(count * size, cache);
if (p) internal_memset(p, 0, count * size);
return p;
}
void InternalFree(void *addr, InternalAllocatorCache *cache) {
if (!addr)
return;
addr = (char*)addr - sizeof(u64);
CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
((u64*)addr)[0] = 0;
RawInternalFree(addr, cache);
}
// LowLevelAllocator
static LowLevelAllocateCallback low_level_alloc_callback;
void *LowLevelAllocator::Allocate(uptr size) {
// Align allocation size.
size = RoundUpTo(size, 8);
if (allocated_end_ - allocated_current_ < (sptr)size) {
uptr size_to_allocate = Max(size, GetPageSizeCached());
allocated_current_ =
(char*)MmapOrDie(size_to_allocate, __func__);
allocated_end_ = allocated_current_ + size_to_allocate;
if (low_level_alloc_callback) {
low_level_alloc_callback((uptr)allocated_current_,
size_to_allocate);
}
}
CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
void *res = allocated_current_;
allocated_current_ += size;
return res;
}
void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
low_level_alloc_callback = callback;
}
bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n) {
if (!size) return false;
uptr max = (uptr)-1L;
return (max / size) < n;
}
static atomic_uint8_t reporting_out_of_memory = {0};
bool IsReportingOOM() { return atomic_load_relaxed(&reporting_out_of_memory); }
void NORETURN ReportAllocatorCannotReturnNull(bool out_of_memory) {
if (out_of_memory) atomic_store_relaxed(&reporting_out_of_memory, 1);
Report("%s's allocator is terminating the process instead of returning 0\n",
SanitizerToolName);
Report("If you don't like this behavior set allocator_may_return_null=1\n");
CHECK(0);
Die();
}
} // namespace __sanitizer