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Add debug sentinel to GrMemoryPool to check for memory stomping

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GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1553233006

Review URL: https://codereview.chromium.org/1553233006
This commit is contained in:
robertphillips 2016-01-06 07:04:46 -08:00 committed by Commit bot
parent bc348f41a7
commit 19c6250cad
2 changed files with 24 additions and 5 deletions
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17
src/gpu/GrMemoryPool.cpp
View File

@ -40,8 +40,8 @@ GrMemoryPool::~GrMemoryPool() {
void* GrMemoryPool::allocate(size_t size) {
VALIDATE;
size = GrSizeAlignUp(size, kAlignment);
size += kPerAllocPad;
size = GrSizeAlignUp(size, kAlignment);
if (fTail->fFreeSize < size) {
size_t blockSize = size;
blockSize = SkTMax<size_t>(blockSize, fMinAllocSize);
@ -59,7 +59,9 @@ void* GrMemoryPool::allocate(size_t size) {
intptr_t ptr = fTail->fCurrPtr;
// We stash a pointer to the block header, just before the allocated space,
// so that we can decrement the live count on delete in constant time.
*reinterpret_cast<BlockHeader**>(ptr) = fTail;
AllocHeader* allocData = reinterpret_cast<AllocHeader*>(ptr);
SkDEBUGCODE(allocData->fSentinal = kAssignedMarker);
allocData->fHeader = fTail;
ptr += kPerAllocPad;
fTail->fPrevPtr = fTail->fCurrPtr;
fTail->fCurrPtr += size;
@ -74,7 +76,10 @@ void* GrMemoryPool::allocate(size_t size) {
void GrMemoryPool::release(void* p) {
VALIDATE;
intptr_t ptr = reinterpret_cast<intptr_t>(p) - kPerAllocPad;
BlockHeader* block = *reinterpret_cast<BlockHeader**>(ptr);
AllocHeader* allocData = reinterpret_cast<AllocHeader*>(ptr);
SkASSERT(kAssignedMarker == allocData->fSentinal);
SkDEBUGCODE(allocData->fSentinal = kFreedMarker);
BlockHeader* block = allocData->fHeader;
if (1 == block->fLiveCount) {
// the head block is special, it is reset rather than deleted
if (fHead == block) {
@ -159,8 +164,12 @@ void GrMemoryPool::validate() {
SkASSERT(ptrOffset == kHeaderSize);
SkASSERT(userStart == block->fCurrPtr);
} else {
SkASSERT(block == *reinterpret_cast<BlockHeader**>(userStart));
AllocHeader* allocData = reinterpret_cast<AllocHeader*>(userStart);
SkASSERT(allocData->fSentinal == kAssignedMarker ||
allocData->fSentinal == kFreedMarker);
SkASSERT(block == allocData->fHeader);
}
prev = block;
} while ((block = block->fNext));
SkASSERT(allocCount == fAllocationCnt);

12
src/gpu/GrMemoryPool.h
View File

@ -68,11 +68,21 @@ private:
size_t fSize; ///< total allocated size of the block
};
static const uint32_t kAssignedMarker = 0xCDCDCDCD;
static const uint32_t kFreedMarker = 0xEFEFEFEF;
struct AllocHeader {
#ifdef SK_DEBUG
uint32_t fSentinal; ///< known value to check for memory stomping (e.g., (CD)*)
#endif
BlockHeader* fHeader; ///< pointer back to the block header in which an alloc resides
};
enum {
// We assume this alignment is good enough for everybody.
kAlignment = 8,
kHeaderSize = GR_CT_ALIGN_UP(sizeof(BlockHeader), kAlignment),
kPerAllocPad = GR_CT_ALIGN_UP(sizeof(BlockHeader*), kAlignment),
kPerAllocPad = GR_CT_ALIGN_UP(sizeof(AllocHeader), kAlignment),
};
size_t fSize;
size_t fPreallocSize;