+/// Allocate - Allocate space at the specified alignment.
+///
+void *BumpPtrAllocator::Allocate(size_t Size, size_t Alignment) {
+ if (!CurSlab) // Start a new slab if we haven't allocated one already.
+ StartNewSlab();
+
+ // Keep track of how many bytes we've allocated.
+ BytesAllocated += Size;
+
+ // 0-byte alignment means 1-byte alignment.
+ if (Alignment == 0) Alignment = 1;
+
+ // Allocate the aligned space, going forwards from CurPtr.
+ char *Ptr = AlignPtr(CurPtr, Alignment);
+
+ // Check if we can hold it.
+ if (Ptr + Size <= End) {
+ CurPtr = Ptr + 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(Ptr, Size);
+ return Ptr;
+ }
+
+ // If Size is really big, allocate a separate slab for it.
+ size_t PaddedSize = Size + sizeof(MemSlab) + Alignment - 1;
+ if (PaddedSize > SizeThreshold) {
+ MemSlab *NewSlab = Allocator.Allocate(PaddedSize);
+
+ // Put the new slab after the current slab, since we are not allocating
+ // into it.
+ NewSlab->NextPtr = CurSlab->NextPtr;
+ CurSlab->NextPtr = NewSlab;
+
+ Ptr = AlignPtr((char*)(NewSlab + 1), Alignment);
+ assert((uintptr_t)Ptr + Size <= (uintptr_t)NewSlab + NewSlab->Size);
+ __msan_allocated_memory(Ptr, Size);
+ return Ptr;
+ }
+
+ // Otherwise, start a new slab and try again.
+ StartNewSlab();
+ Ptr = AlignPtr(CurPtr, Alignment);
+ CurPtr = Ptr + Size;
+ assert(CurPtr <= End && "Unable to allocate memory!");
+ __msan_allocated_memory(Ptr, Size);