void*
nsPresArena::Allocate(uint32_t aCode, size_t aSize)
{
NS_ABORT_IF_FALSE(aSize > 0, "PresArena cannot allocate zero bytes");
// We only hand out aligned sizes
aSize = PL_ARENA_ALIGN(&mPool, aSize);
// If there is no free-list entry for this type already, we have
// to create one now, to record its size.
FreeList* list = mFreeLists.PutEntry(aCode);
nsTArray<void*>::index_type len = list->mEntries.Length();
if (list->mEntrySize == 0) {
NS_ABORT_IF_FALSE(len == 0, "list with entries but no recorded size");
list->mEntrySize = aSize;
} else {
NS_ABORT_IF_FALSE(list->mEntrySize == aSize,
"different sizes for same object type code");
}
void* result;
if (len > 0) {
// LIFO behavior for best cache utilization
result = list->mEntries.ElementAt(len - 1);
list->mEntries.RemoveElementAt(len - 1);
#if defined(DEBUG)
{
MOZ_MAKE_MEM_DEFINED(result, list->mEntrySize);
char* p = reinterpret_cast<char*>(result);
char* limit = p + list->mEntrySize;
for (; p < limit; p += sizeof(uintptr_t)) {
uintptr_t val = *reinterpret_cast<uintptr_t*>(p);
NS_ABORT_IF_FALSE(val == mozPoisonValue(),
nsPrintfCString("PresArena: poison overwritten; "
"wanted %.16llx "
"found %.16llx "
"errors in bits %.16llx",
uint64_t(mozPoisonValue()),
uint64_t(val),
uint64_t(mozPoisonValue() ^ val)
).get());
}
}
#endif
MOZ_MAKE_MEM_UNDEFINED(result, list->mEntrySize);
return result;
}
// Allocate a new chunk from the arena
list->mEntriesEverAllocated++;
PL_ARENA_ALLOCATE(result, &mPool, aSize);
if (!result) {
NS_ABORT_OOM(aSize);
}
return result;
}
/* static */ PLDHashOperator
nsPresArena::UnpoisonFreeList(FreeList* aEntry, void*)
{
nsTArray<void*>::index_type len;
while ((len = aEntry->mEntries.Length())) {
void* result = aEntry->mEntries.ElementAt(len - 1);
aEntry->mEntries.RemoveElementAt(len - 1);
MOZ_MAKE_MEM_UNDEFINED(result, aEntry->mEntrySize);
}
return PL_DHASH_NEXT;
}
void
BumpChunk::delete_(BumpChunk *chunk)
{
#ifdef DEBUG
// Part of the chunk may have been marked as poisoned/noaccess. Undo that
// before writing the 0xcd bytes.
size_t size = sizeof(*chunk) + chunk->bumpSpaceSize;
MOZ_MAKE_MEM_UNDEFINED(chunk, size);
memset(chunk, 0xcd, size);
#endif
js_free(chunk);
}
