-/// BumpPtrAllocator - This allocator is useful for containers that need
-/// very simple memory allocation strategies. In particular, this just keeps
-/// allocating memory, and never deletes it until the entire block is dead. This
-/// makes allocation speedy, but must only be used when the trade-off is ok.
-class BumpPtrAllocator {
- BumpPtrAllocator(const BumpPtrAllocator &); // do not implement
- void operator=(const BumpPtrAllocator &); // do not implement
+ /// \brief Allocate space at the specified alignment.
+ LLVM_ATTRIBUTE_RETURNS_NONNULL void *Allocate(size_t Size, size_t Alignment) {
+ assert(Alignment > 0 && "0-byte alignnment is not allowed. Use 1 instead.");
+
+ // Keep track of how many bytes we've allocated.
+ BytesAllocated += Size;
+
+ size_t Adjustment = alignmentAdjustment(CurPtr, Alignment);
+ assert(Adjustment + Size >= Size && "Adjustment + Size must not overflow");
+
+ // Check if we have enough space.
+ if (Adjustment + Size <= size_t(End - CurPtr)) {
+ char *AlignedPtr = CurPtr + Adjustment;
+ CurPtr = AlignedPtr + Size;
+ // Update the allocation point of this memory block in MemorySanitizer.
+ // Without this, MemorySanitizer messages for values originated from here
+ // will point to the allocation of the entire slab.
+ __msan_allocated_memory(AlignedPtr, Size);
+ return AlignedPtr;
+ }
+
+ // If Size is really big, allocate a separate slab for it.
+ size_t PaddedSize = Size + Alignment - 1;
+ if (PaddedSize > SizeThreshold) {
+ void *NewSlab = Allocator.Allocate(PaddedSize, 0);
+ CustomSizedSlabs.push_back(std::make_pair(NewSlab, PaddedSize));
+
+ uintptr_t AlignedAddr = alignAddr(NewSlab, Alignment);
+ assert(AlignedAddr + Size <= (uintptr_t)NewSlab + PaddedSize);
+ char *AlignedPtr = (char*)AlignedAddr;
+ __msan_allocated_memory(AlignedPtr, Size);
+ return AlignedPtr;
+ }
+
+ // Otherwise, start a new slab and try again.
+ StartNewSlab();
+ uintptr_t AlignedAddr = alignAddr(CurPtr, Alignment);
+ assert(AlignedAddr + Size <= (uintptr_t)End &&
+ "Unable to allocate memory!");
+ char *AlignedPtr = (char*)AlignedAddr;
+ CurPtr = AlignedPtr + Size;
+ __msan_allocated_memory(AlignedPtr, Size);
+ return AlignedPtr;
+ }