void FixedAlloc::Destroy()
{
// Free all of the blocks
while (m_firstBlock) {
#ifdef MMGC_MEMORY_PROFILER
if(m_firstBlock->numAlloc > 0 && m_heap->GetStatus() != kMemAbort) {
union {
char* mem_c;
uint32_t* mem;
};
mem_c = m_firstBlock->items;
unsigned int itemNum = 0;
while(itemNum++ < m_itemsPerBlock) {
if(IsInUse(m_firstBlock, mem)) {
GCLog("Leaked %d byte item. Addr: 0x%p\n", GetItemSize(), GetUserPointer(mem));
PrintAllocStackTrace(GetUserPointer(mem));
}
mem_c += m_itemSize;
}
}
#ifdef MMGC_MEMORY_INFO
//check for writes on deleted memory
VerifyFreeBlockIntegrity(m_firstBlock->firstFree, m_firstBlock->size);
#endif
#endif
FreeChunk(m_firstBlock);
}
m_firstBlock = NULL;
}
void GCLargeAlloc::Finalize()
{
m_startedFinalize = true;
LargeBlock **prev = &m_blocks;
while (*prev) {
LargeBlock *b = *prev;
if ((b->flags & kMarkFlag) == 0) {
void *item = b+1;
if (NeedsFinalize(b)) {
GCFinalizable *obj = (GCFinalizable *) item;
obj = (GCFinalizable *) GetUserPointer(obj);
//obj->~GCFinalizable();
obj->Finalize();
#if defined(_DEBUG) && defined(MMGC_DRC)
if((b->flags & kRCObject) != 0) {
b->gc->RCObjectZeroCheck((RCObject*)obj);
}
#endif
}
if(b->flags & kHasWeakRef) {
b->gc->ClearWeakRef(GetUserPointer(item));
}
SAMPLE_DEALLOC(item, GC::Size(item));
// unlink from list
*prev = b->next;
b->gc->AddToLargeEmptyBlockList(b);
continue;
}
// clear marks
b->flags &= ~(kMarkFlag|kQueuedFlag);
prev = &b->next;
}
m_startedFinalize = false;
}
void GCLargeAlloc::Free(const void *item)
{
LargeBlock *b = GetLargeBlock(item);
#ifdef GCDEBUG
// RCObject have contract that they must clean themselves, since they
// have to scan themselves to decrement other RCObjects they might as well
// clean themselves too, better than suffering a memset later
if(b->rcobject)
m_gc->RCObjectZeroCheck((RCObject*)GetUserPointer(item));
#endif
// We can't allow free'ing something during Sweeping, otherwise alloc counters
// get decremented twice and destructors will be called twice.
GCAssert(m_gc->collecting == false || m_gc->marking == true);
if (m_gc->marking && (m_gc->collecting || IsProtectedAgainstFree(b))) {
m_gc->AbortFree(GetUserPointer(item));
return;
}
m_gc->policy.signalFreeWork(b->size);
#ifdef MMGC_HOOKS
GCHeap* heap = GCHeap::GetGCHeap();
if(heap->HooksEnabled())
{
const void* p = GetUserPointer(item);
size_t userSize = GC::Size(p);
#ifdef MMGC_MEMORY_PROFILER
if(heap->GetProfiler())
m_totalAskSize -= heap->GetProfiler()->GetAskSize(p);
#endif
heap->FinalizeHook(p, userSize);
heap->FreeHook(p, userSize, uint8_t(GCHeap::GCFreedPoison));
}
#endif
if(b->flags[0] & kHasWeakRef)
m_gc->ClearWeakRef(GetUserPointer(item));
LargeBlock **prev = &m_blocks;
while(*prev)
{
if(b == *prev)
{
*prev = Next(b);
size_t numBlocks = b->GetNumBlocks();
m_totalAllocatedBytes -= b->size;
VALGRIND_MEMPOOL_FREE(b, b);
VALGRIND_MEMPOOL_FREE(b, item);
VALGRIND_DESTROY_MEMPOOL(b);
m_gc->FreeBlock(b, (uint32_t)numBlocks, m_partitionIndex);
return;
}
prev = (LargeBlock**)(&(*prev)->next);
}
GCAssertMsg(false, "Bad free!");
}
/* static */
void GCAlloc::Free(const void *item)
{
GCBlock *b = GetBlock(item);
GCAlloc *a = b->alloc;
#ifdef MMGC_HOOKS
GCHeap* heap = GCHeap::GetGCHeap();
if(heap->HooksEnabled())
{
const void* p = GetUserPointer(item);
size_t userSize = GC::Size(p);
#ifdef MMGC_MEMORY_PROFILER
if(heap->GetProfiler())
a->m_totalAskSize -= heap->GetProfiler()->GetAskSize(p);
#endif
heap->FinalizeHook(p, userSize);
heap->FreeHook(p, userSize, 0xca);
}
#endif
#ifdef _DEBUG
// check that its not already been freed
void *free = b->firstFree;
while(free) {
GCAssert(free != item);
free = *((void**) free);
}
#endif
int index = GetIndex(b, item);
if(GetBit(b, index, kHasWeakRef)) {
b->gc->ClearWeakRef(GetUserPointer(item));
}
bool wasFull = b->IsFull();
if(b->needsSweeping) {
#ifdef _DEBUG
bool gone =
#endif
a->Sweep(b);
GCAssertMsg(!gone, "How can a page I'm about to free an item on be empty?");
wasFull = false;
}
if(wasFull) {
a->AddToFreeList(b);
}
b->FreeItem(item, index);
if(b->numItems == 0) {
a->UnlinkChunk(b);
a->FreeChunk(b);
}
}
/*static*/
const void *FixedAlloc::FindBeginning(const void *addr)
{
FixedBlock *b = GetFixedBlock(addr);
uint32_t itemNum = 0;
char *mem = b->items;
while(itemNum++ < b->alloc->m_itemsPerBlock) {
char *next = mem + b->alloc->m_itemSize;
if(addr >= mem && addr < next)
return GetUserPointer(mem);
mem = next;
}
return NULL;
}
void GCLargeAlloc::Free(const void *item)
{
LargeBlock *b = GetBlockHeader(item);
if(b->flags & kHasWeakRef)
b->gc->ClearWeakRef(GetUserPointer(item));
LargeBlock **prev = &m_blocks;
while(*prev)
{
if(b == *prev)
{
*prev = b->next;
m_gc->FreeBlock(b, b->GetNumBlocks());
return;
}
prev = &(*prev)->next;
}
GCAssertMsg(false, "Bad free!");
}
void FixedAlloc::Destroy()
{
// Free all of the blocks
while (m_firstBlock) {
#ifdef MMGC_MEMORY_PROFILER
if(m_firstBlock->numAlloc > 0 && m_heap->GetStatus() != kMemAbort) {
union {
char* mem_c;
uint32_t* mem;
};
mem_c = m_firstBlock->items;
unsigned int itemNum = 0;
while(itemNum++ < m_itemsPerBlock) {
if(IsInUse(m_firstBlock, mem)) {
// supress output in release build UNLESS the profiler is on
#ifndef GCDEBUG
if(m_heap->GetProfiler() != NULL)
#endif
{
GCLog("Leaked %d byte item. Addr: 0x%p\n", GetItemSize(), GetUserPointer(mem));
PrintAllocStackTrace(GetUserPointer(mem));
}
}
mem_c += m_itemSize;
}
}
#ifdef MMGC_MEMORY_INFO
//check for writes on deleted memory
VerifyFreeBlockIntegrity(m_firstBlock->firstFree, m_firstBlock->size);
#endif
#endif
// Note, don't cache any state across this call; FreeChunk may temporarily
// release locks held if the true type of this allocator is FixedAllocSafe.
FreeChunk(m_firstBlock);
}
m_firstBlock = NULL;
}
void *FixedMalloc::LargeAlloc(size_t size, FixedMallocOpts flags)
{
GCHeap::CheckForAllocSizeOverflow(size, GCHeap::kBlockSize+DebugSize());
size += DebugSize();
int blocksNeeded = (int)GCHeap::SizeToBlocks(size);
uint32_t gcheap_flags = GCHeap::kExpand;
if((flags & kCanFail) != 0)
gcheap_flags |= GCHeap::kCanFail;
if((flags & kZero) != 0)
gcheap_flags |= GCHeap::kZero;
void *item = m_heap->Alloc(blocksNeeded, gcheap_flags);
if(item)
{
item = GetUserPointer(item);
#ifdef MMGC_HOOKS
if(m_heap->HooksEnabled())
m_heap->AllocHook(item, size - DebugSize(), Size(item));
#endif // MMGC_HOOKS
UpdateLargeAllocStats(item, blocksNeeded);
#ifdef DEBUG
// Fresh memory poisoning
if((flags & kZero) == 0)
memset(item, uint8_t(GCHeap::FXFreshPoison), size - DebugSize());
#ifndef AVMPLUS_SAMPLER
// Enregister the large object
AddToLargeObjectTracker(item);
#endif
#endif // DEBUG
}
return item;
}
void GCAlloc::SweepGuts(GCBlock *b)
{
// TODO: MMX version for IA32
uint32_t *bits = (uint32_t*) b->GetBits();
uint32_t count = b->nextItem ? GetIndex(b, b->nextItem) : m_itemsPerBlock;
// round up to eight
uint32_t numInts = ((count+7)&~7) >> 3;
for(uint32_t i=0; i < numInts; i++)
{
uint32_t marks = bits[i];
// hmm, is it better to screw around with exact counts or just examine
// 8 items on each pass, with the later we open the door to unrolling
uint32_t subCount = i==(numInts-1) ? ((count-1)&7)+1 : 8;
for(uint32_t j=0; j<subCount;j++,marks>>=4)
{
int mq = marks & kFreelist;
if(mq == kMark || mq == kQueued) // Sweeping is lazy; don't sweep objects on the mark stack
{
// live item, clear bits
bits[i] &= ~(kFreelist<<(j*4));
continue;
}
if(mq == kFreelist)
continue; // freelist item, ignore
// garbage, freelist it
void *item = (char*)b->items + m_itemSize*(i*8+j);
#ifdef MMGC_HOOKS
if(m_gc->heap->HooksEnabled())
m_gc->heap->FreeHook(GetUserPointer(item), b->size - DebugSize(), 0xba);
#endif
b->FreeItem(item, (i*8+j));
}
}
}
GCAlloc::GCBlock* GCAlloc::CreateChunk(int flags)
{
// Too many definitions of kBlockSize, make sure they're at least in sync.
GCAssert(uint32_t(kBlockSize) == GCHeap::kBlockSize);
// Get bitmap space; this may trigger OOM handling.
gcbits_t* bits = m_bitsInPage ? NULL : (gcbits_t*)m_gc->AllocBits(m_numBitmapBytes, m_sizeClassIndex);
// Allocate a new block; this may trigger OOM handling (though that
// won't affect the bitmap space, which is not GC'd individually).
GCBlock* b = (GCBlock*) m_gc->AllocBlock(1, PageMap::kGCAllocPage, /*zero*/true, (flags&GC::kCanFail) != 0);
if (b)
{
VALGRIND_CREATE_MEMPOOL(b, 0/*redZoneSize*/, 1/*zeroed*/);
// treat block header as a separate allocation
VALGRIND_MEMPOOL_ALLOC(b, b, sizeof(GCBlock));
b->gc = m_gc;
b->alloc = this;
b->size = m_itemSize;
b->slowFlags = 0;
if(m_gc->collecting && m_finalized)
b->finalizeState = m_gc->finalizedValue;
else
b->finalizeState = !m_gc->finalizedValue;
b->bibopTag = m_bibopTag;
#ifdef MMGC_FASTBITS
b->bitsShift = (uint8_t) m_bitsShift;
#endif
b->containsPointers = ContainsPointers();
b->rcobject = ContainsRCObjects();
if (m_bitsInPage)
b->bits = (gcbits_t*)b + sizeof(GCBlock);
else
b->bits = bits;
// ditto for in page bits
if (m_bitsInPage) {
VALGRIND_MEMPOOL_ALLOC(b, b->bits, m_numBitmapBytes);
}
// Link the block at the end of the list
b->prev = m_lastBlock;
b->next = 0;
if (m_lastBlock) {
m_lastBlock->next = b;
}
if (!m_firstBlock) {
m_firstBlock = b;
}
m_lastBlock = b;
// Add our new ChunkBlock to the firstFree list (which should be empty)
if (m_firstFree)
{
GCAssert(m_firstFree->prevFree == 0);
m_firstFree->prevFree = b;
}
b->nextFree = m_firstFree;
b->prevFree = 0;
m_firstFree = b;
// calculate back from end (better alignment, no dead space at end)
b->items = (char*)b+GCHeap::kBlockSize - m_itemsPerBlock * m_itemSize;
b->numFree = (short)m_itemsPerBlock;
// explode the new block onto its free list
//
// We must make the object look free, which means poisoning it properly and setting
// the mark bits correctly.
b->firstFree = b->items;
void** p = (void**)(void*)b->items;
int limit = m_itemsPerBlock-1;
#ifdef MMGC_HOOKS
GCHeap* heap = GCHeap::GetGCHeap();
#endif
for ( int i=0 ; i < limit ; i++ ) {
#ifdef MMGC_HOOKS
#ifdef MMGC_MEMORY_INFO // DebugSize is 0 if MEMORY_INFO is off, so we get an "obviously true" warning from GCC.
GCAssert(m_itemSize >= DebugSize());
#endif
if(heap->HooksEnabled())
heap->PseudoFreeHook(GetUserPointer(p), m_itemSize - DebugSize(), uint8_t(GCHeap::GCSweptPoison));
#endif
p = FLSeed(p, (char*)p + m_itemSize);
}
#ifdef MMGC_HOOKS
if(heap->HooksEnabled())
heap->PseudoFreeHook(GetUserPointer(p), m_itemSize - DebugSize(), uint8_t(GCHeap::GCSweptPoison));
#endif
p[0] = NULL;
// Set all the mark bits to 'free'
GCAssert(sizeof(gcbits_t) == 1);
GCAssert(kFreelist == 3);
GCAssert(m_numBitmapBytes % 4 == 0);
uint32_t *pbits = (uint32_t*)(void *)b->bits;
for(int i=0, n=m_numBitmapBytes>>2; i < n; i++)
pbits[i] = 0x03030303;
#ifdef MMGC_MEMORY_INFO
VerifyFreeBlockIntegrity(b->firstFree, m_itemSize);
#endif
}
else {
if (bits)
void* GCLargeAlloc::Alloc(size_t requestSize, int flags)
#endif
{
#ifdef DEBUG
m_gc->heap->CheckForOOMAbortAllocation();
#endif
GCHeap::CheckForAllocSizeOverflow(requestSize, sizeof(LargeBlock)+GCHeap::kBlockSize);
int blocks = (int)((requestSize+sizeof(LargeBlock)+GCHeap::kBlockSize-1) / GCHeap::kBlockSize);
uint32_t computedSize = blocks*GCHeap::kBlockSize - sizeof(LargeBlock);
// Allocation must be signalled before we allocate because no GC work must be allowed to
// come between an allocation and an initialization - if it does, we may crash, as
// GCFinalizedObject subclasses may not have a valid vtable, but the GC depends on them
// having it. In principle we could signal allocation late but only set the object
// flags after signaling, but we might still cause trouble for the profiler, which also
// depends on non-interruptibility.
m_gc->SignalAllocWork(computedSize);
// Pointer containing memory is always zeroed (see bug 594533).
if((flags&GC::kContainsPointers) != 0)
flags |= GC::kZero;
LargeBlock *block = (LargeBlock*) m_gc->AllocBlock(blocks, PageMap::kGCLargeAllocPageFirst,
(flags&GC::kZero) != 0, (flags&GC::kCanFail) != 0);
void *item = NULL;
if (block)
{
// Code below uses these optimizations
GCAssert((unsigned long)GC::kFinalize == (unsigned long)kFinalizable);
GCAssert((unsigned long)GC::kInternalExact == (unsigned long)kVirtualGCTrace);
gcbits_t flagbits0 = 0;
gcbits_t flagbits1 = 0;
#if defined VMCFG_EXACT_TRACING
flagbits0 = (flags & (GC::kFinalize|GC::kInternalExact));
#elif defined VMCFG_SELECTABLE_EXACT_TRACING
flagbits0 = (flags & (GC::kFinalize|m_gc->runtimeSelectableExactnessFlag)); // 0 or GC::kInternalExact
#else
flagbits0 = (flags & GC::kFinalize);
#endif
VALGRIND_CREATE_MEMPOOL(block, /*rdzone*/0, (flags&GC::kZero) != 0);
VALGRIND_MEMPOOL_ALLOC(block, block, sizeof(LargeBlock));
block->gc = this->m_gc;
block->alloc= this;
block->next = m_blocks;
block->size = computedSize;
block->bibopTag = 0;
#ifdef MMGC_FASTBITS
block->bitsShift = 12; // Always use bits[0]
#endif
block->containsPointers = ((flags&GC::kContainsPointers) != 0) ? 1 : 0;
block->rcobject = ((flags&GC::kRCObject) != 0) ? 1 : 0;
block->bits = block->flags;
m_blocks = block;
item = block->GetObject();
if(m_gc->collecting && !m_startedFinalize)
flagbits0 |= kMark;
block->flags[0] = flagbits0;
block->flags[1] = flagbits1;
#ifdef _DEBUG
(void)originalSize;
if (flags & GC::kZero)
{
if (!RUNNING_ON_VALGRIND)
{
// AllocBlock should take care of this
for(int i=0, n=(int)(requestSize/sizeof(int)); i<n; i++) {
if(((int*)item)[i] != 0)
GCAssert(false);
}
}
}
#endif
// see comments in GCAlloc about using full size instead of ask size
VALGRIND_MEMPOOL_ALLOC(block, item, computedSize);
#ifdef MMGC_HOOKS
GCHeap* heap = GCHeap::GetGCHeap();
if(heap->HooksEnabled()) {
size_t userSize = block->size - DebugSize();
#ifdef MMGC_MEMORY_PROFILER
m_totalAskSize += originalSize;
heap->AllocHook(GetUserPointer(item), originalSize, userSize, /*managed=*/true);
#else
heap->AllocHook(GetUserPointer(item), 0, userSize, /*managed=*/true);
#endif
}
#endif
}
return item;
}
void GCLargeAlloc::Finalize()
{
m_startedFinalize = true;
LargeBlock **prev = &m_blocks;
while (*prev) {
LargeBlock *b = *prev;
if ((b->flags[0] & kMark) == 0)
{
GCAssert((b->flags[0] & kQueued) == 0);
GC* gc = b->gc;
// GC::Finalize calls GC::MarkOrClearWeakRefs before calling GCAlloc::Finalize,
// ergo there should be no unmarked objects with weak refs.
GCAssertMsg((b->flags[0] & kHasWeakRef) == 0, "No unmarked object should have a weak ref at this point");
// Large blocks may be allocated by finalizers for large blocks, creating contention
// for the block list. Yet the block list must be live, since eg GetUsageInfo may be
// called by the finalizers (or their callees).
//
// Unlink the block from the list early to avoid contention.
*prev = Next(b);
b->next = NULL;
void *item = b+1;
if (b->flags[0] & kFinalizable)
{
GCFinalizedObject *obj = (GCFinalizedObject *) item;
obj = (GCFinalizedObject *) GetUserPointer(obj);
obj->~GCFinalizedObject();
#if defined(_DEBUG)
if(b->rcobject) {
gc->RCObjectZeroCheck((RCObject*)obj);
}
#endif
}
// GC::GetWeakRef will not allow a weak reference to be created to an object that
// is ready for destruction.
GCAssertMsg((b->flags[0] & kHasWeakRef) == 0, "No unmarked object should have a weak ref at this point");
#ifdef MMGC_HOOKS
if(m_gc->heap->HooksEnabled())
{
#ifdef MMGC_MEMORY_PROFILER
if(GCHeap::GetGCHeap()->GetProfiler())
m_totalAskSize -= GCHeap::GetGCHeap()->GetProfiler()->GetAskSize(GetUserPointer(item));
#endif
m_gc->heap->FinalizeHook(GetUserPointer(item), b->size - DebugSize());
}
#endif
// The block is not empty until now, so now add it.
gc->AddToLargeEmptyBlockList(b);
continue;
}
// clear marks
b->flags[0] &= ~(kMark|kQueued);
prev = (LargeBlock**)(&b->next);
}
m_startedFinalize = false;
}
void GCAlloc::Finalize()
{
m_finalized = true;
// Go through every item of every block. Look for items
// that are in use but not marked as reachable, and delete
// them.
GCBlock *next = NULL;
for (GCBlock* b = m_firstBlock; b != NULL; b = next)
{
// we can unlink block below
next = Next(b);
GCAssert(!b->needsSweeping);
// remove from freelist to avoid mutator destructor allocations
// from using this block
bool putOnFreeList = false;
if(m_firstFree == b || b->prevFree != NULL || b->nextFree != NULL) {
putOnFreeList = true;
RemoveFromFreeList(b);
}
GCAssert(kMark == 0x1 && kFinalize == 0x4 && kHasWeakRef == 0x8);
int numMarkedItems = 0;
// TODO: MMX version for IA32
uint32_t *bits = (uint32_t*) b->GetBits();
uint32_t count = b->nextItem ? GetIndex(b, b->nextItem) : m_itemsPerBlock;
// round up to eight
uint32_t numInts = ((count+7)&~7) >> 3;
for(uint32_t i=0; i < numInts; i++)
{
uint32_t marks = bits[i];
// hmm, is it better to screw around with exact counts or just examine
// 8 items on each pass, with the later we open the door to unrolling
uint32_t subCount = i==(numInts-1) ? ((count-1)&7)+1 : 8;
for(uint32_t j=0; j<subCount;j++,marks>>=4)
{
int mq = marks & kFreelist;
if(mq == kFreelist)
continue;
if(mq == kMark) {
numMarkedItems++;
continue;
}
GCAssertMsg(mq != kQueued, "No queued objects should exist when finalizing");
void* item = (char*)b->items + m_itemSize*((i*8)+j);
#ifdef MMGC_HOOKS
if(m_gc->heap->HooksEnabled())
{
#ifdef MMGC_MEMORY_PROFILER
if(m_gc->heap->GetProfiler())
m_totalAskSize -= m_gc->heap->GetProfiler()->GetAskSize(GetUserPointer(item));
#endif
m_gc->heap->FinalizeHook(GetUserPointer(item), m_itemSize - DebugSize());
}
#endif
if(!(marks & (kFinalize|kHasWeakRef)))
continue;
if (marks & kFinalize)
{
GCFinalizedObject *obj = (GCFinalizedObject*)GetUserPointer(item);
GCAssert(*(intptr_t*)obj != 0);
bits[i] &= ~(kFinalize<<(j*4)); // Clear bits first so we won't get second finalization if finalizer longjmps out
obj->~GCFinalizedObject();
#if defined(_DEBUG)
if(b->alloc->ContainsRCObjects()) {
m_gc->RCObjectZeroCheck((RCObject*)obj);
}
#endif
}
if (marks & kHasWeakRef) {
b->gc->ClearWeakRef(GetUserPointer(item));
}
}
}
// 3 outcomes:
// 1) empty, put on list of empty pages
// 2) no freed items, partially empty or full, return to free if partially empty
// 3) some freed item add to the to be swept list
if(numMarkedItems == 0) {
// add to list of block to be returned to the Heap after finalization
// we don't do this during finalization b/c we want finalizers to be able
// to reference the memory of other objects being finalized
UnlinkChunk(b);
b->gc->AddToSmallEmptyBlockList(b);
putOnFreeList = false;
} else if(numMarkedItems == b->numItems) {
// nothing changed on this page, clear marks
// note there will be at least one free item on the page (otherwise it
// would not have been scanned) so the page just stays on the freelist
ClearMarks(b);
} else if(!b->needsSweeping) {
// free'ing some items but not all
if(b->nextFree || b->prevFree || b == m_firstFree) {
RemoveFromFreeList(b);
b->nextFree = b->prevFree = NULL;
}
AddToSweepList(b);
putOnFreeList = false;
}
b->finalizeState = m_gc->finalizedValue;
if(putOnFreeList)
AddToFreeList(b);
}
}
void* GCAlloc::Alloc(int flags)
#endif
{
GCAssertMsg(((size_t)m_itemSize >= size), "allocator itemsize too small");
// Allocation must be signalled before we allocate because no GC work must be allowed to
// come between an allocation and an initialization - if it does, we may crash, as
// GCFinalizedObject subclasses may not have a valid vtable, but the GC depends on them
// having it. In principle we could signal allocation late but only set the object
// flags after signaling, but we might still cause trouble for the profiler, which also
// depends on non-interruptibility.
m_gc->SignalAllocWork(m_itemSize);
GCBlock* b = m_firstFree;
start:
if (b == NULL) {
if (m_needsSweeping && !m_gc->collecting) {
Sweep(m_needsSweeping);
b = m_firstFree;
goto start;
}
bool canFail = (flags & GC::kCanFail) != 0;
CreateChunk(canFail);
b = m_firstFree;
if (b == NULL) {
GCAssert(canFail);
return NULL;
}
}
GCAssert(!b->needsSweeping);
GCAssert(b == m_firstFree);
GCAssert(b && !b->IsFull());
void *item;
if(b->firstFree) {
item = b->firstFree;
b->firstFree = *((void**)item);
// clear free list pointer, the rest was zero'd in free
*(intptr_t*) item = 0;
#ifdef MMGC_MEMORY_INFO
//check for writes on deleted memory
VerifyFreeBlockIntegrity(item, b->size);
#endif
} else {
item = b->nextItem;
if(((uintptr_t)((char*)item + b->size) & 0xfff) != 0) {
b->nextItem = (char*)item + b->size;
} else {
b->nextItem = NULL;
}
}
// set up bits, items start out white and whether they need finalization
// is determined by the caller
// make sure we ended up in the right place
GCAssert(((flags&GC::kContainsPointers) != 0) == ContainsPointers());
// this assumes what we assert
GCAssert((unsigned long)GC::kFinalize == (unsigned long)GCAlloc::kFinalize);
int index = GetIndex(b, item);
GCAssert(index >= 0);
Clear4BitsAndSet(b, index, flags & kFinalize);
b->numItems++;
#ifdef MMGC_MEMORY_INFO
m_numAlloc++;
#endif
// If we're out of free items, be sure to remove ourselves from the
// list of blocks with free items. TODO Minor optimization: when we
// carve an item off the end of the block, we don't need to check here
// unless we just set b->nextItem to NULL.
if (b->IsFull()) {
m_firstFree = b->nextFree;
b->nextFree = NULL;
GCAssert(b->prevFree == NULL);
if (m_firstFree)
m_firstFree->prevFree = 0;
}
// prevent mid-collection (ie destructor) allocations on un-swept pages from
// getting swept. If the page is finalized and doesn't need sweeping we don't want
// to set the mark otherwise it will be marked when we start the next marking phase
// and write barriers won't fire (since its black)
if(m_gc->collecting)
{
if((b->finalizeState != m_gc->finalizedValue) || b->needsSweeping)
SetBit(b, index, kMark);
}
GCAssert((uintptr_t(item) & ~0xfff) == (uintptr_t) b);
GCAssert((uintptr_t(item) & 7) == 0);
#ifdef MMGC_HOOKS
GCHeap* heap = GCHeap::GetGCHeap();
if(heap->HooksEnabled())
{
size_t userSize = m_itemSize - DebugSize();
#ifdef MMGC_MEMORY_PROFILER
m_totalAskSize += size;
heap->AllocHook(GetUserPointer(item), size, userSize);
#else
heap->AllocHook(GetUserPointer(item), 0, userSize);
#endif
}
#endif
return item;
}
void* FixedAlloc::Alloc(size_t size, FixedMallocOpts opts)
{
(void)size;
GCAssertMsg(m_heap->StackEnteredCheck() || (opts&kCanFail) != 0, "MMGC_ENTER must be on the stack");
GCAssertMsg(((size_t)m_itemSize >= size), "allocator itemsize too small");
if(!m_firstFree) {
bool canFail = (opts & kCanFail) != 0;
CreateChunk(canFail);
if(!m_firstFree) {
if (!canFail) {
GCAssertMsg(0, "Memory allocation failed to abort properly");
GCHeap::SignalInconsistentHeapState("Failed to abort");
/*NOTREACHED*/
}
return NULL;
}
}
FixedBlock* b = m_firstFree;
GCAssert(b && !IsFull(b));
b->numAlloc++;
// Consume the free list if available
void *item = NULL;
if (b->firstFree) {
item = b->firstFree;
b->firstFree = *((void**)item);
// assert that the freelist hasn't been tampered with (by writing to the first 4 bytes)
GCAssert(b->firstFree == NULL ||
(b->firstFree >= b->items &&
(((uintptr_t)b->firstFree - (uintptr_t)b->items) % b->size) == 0 &&
(uintptr_t) b->firstFree < ((uintptr_t)b & ~0xfff) + GCHeap::kBlockSize));
#ifdef MMGC_MEMORY_INFO
//check for writes on deleted memory
VerifyFreeBlockIntegrity(item, b->size);
#endif
} else {
// Take next item from end of block
item = b->nextItem;
GCAssert(item != 0);
if(!IsFull(b)) {
// There are more items at the end of the block
b->nextItem = (void *) ((uintptr_t)item+m_itemSize);
} else {
b->nextItem = 0;
}
}
// If we're out of free items, be sure to remove ourselves from the
// list of blocks with free items.
if (IsFull(b)) {
m_firstFree = b->nextFree;
b->nextFree = NULL;
GCAssert(b->prevFree == NULL);
if (m_firstFree)
m_firstFree->prevFree = 0;
}
item = GetUserPointer(item);
#ifdef MMGC_HOOKS
if(m_heap->HooksEnabled())
{
#ifdef MMGC_MEMORY_PROFILER
m_totalAskSize += size;
#endif
m_heap->AllocHook(item, size, b->size - DebugSize());
}
#endif
#ifdef _DEBUG
// fresh memory poisoning
if((opts & kZero) == 0)
memset(item, 0xfa, b->size - DebugSize());
#endif
if((opts & kZero) != 0)
memset(item, 0, b->size - DebugSize());
return item;
}