/// \brief Allocate memory in an ever growing pool, as if by bump-pointer.
///
/// This isn't strictly a bump-pointer allocator as it uses backing slabs of
-/// memory rather than relying on boundless contiguous heap. However, it has
-/// bump-pointer semantics in that is a monotonically growing pool of memory
+/// memory rather than relying on a boundless contiguous heap. However, it has
+/// bump-pointer semantics in that it is a monotonically growing pool of memory
/// where every allocation is found by merely allocating the next N bytes in
/// the slab, or the next N bytes in the next slab.
///
: CurPtr(nullptr), End(nullptr), BytesAllocated(0),
Allocator(std::forward<T &&>(Allocator)) {}
- // Manually implement a move constructor as we must clear the old allocators
+ // Manually implement a move constructor as we must clear the old allocator's
// slabs as a matter of correctness.
BumpPtrAllocatorImpl(BumpPtrAllocatorImpl &&Old)
: CurPtr(Old.CurPtr), End(Old.End), Slabs(std::move(Old.Slabs)),
/// \brief Deallocate all but the current slab and reset the current pointer
/// to the beginning of it, freeing all memory allocated so far.
void Reset() {
+ DeallocateCustomSizedSlabs();
+ CustomSizedSlabs.clear();
+
if (Slabs.empty())
return;
CurPtr = (char *)Slabs.front();
End = CurPtr + SlabSize;
- // Deallocate all but the first slab, and all custome sized slabs.
+ // Deallocate all but the first slab, and deallocate all custom-sized slabs.
DeallocateSlabs(std::next(Slabs.begin()), Slabs.end());
Slabs.erase(std::next(Slabs.begin()), Slabs.end());
- DeallocateCustomSizedSlabs();
- CustomSizedSlabs.clear();
}
/// \brief Allocate space at the specified alignment.
- LLVM_ATTRIBUTE_RETURNS_NONNULL void *Allocate(size_t Size, size_t Alignment) {
+ LLVM_ATTRIBUTE_RETURNS_NONNULL LLVM_ATTRIBUTE_RETURNS_NOALIAS 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;
- // Allocate the aligned space, going forwards from CurPtr.
- char *Ptr = alignPtr(CurPtr, Alignment);
+ size_t Adjustment = alignmentAdjustment(CurPtr, Alignment);
+ assert(Adjustment + Size >= Size && "Adjustment + Size must not overflow");
- // Check if we can hold it.
- if (Ptr + Size <= End) {
- CurPtr = Ptr + Size;
+ // 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(Ptr, Size);
- return Ptr;
+ __msan_allocated_memory(AlignedPtr, Size);
+ return AlignedPtr;
}
// If Size is really big, allocate a separate slab for it.
void *NewSlab = Allocator.Allocate(PaddedSize, 0);
CustomSizedSlabs.push_back(std::make_pair(NewSlab, PaddedSize));
- Ptr = alignPtr((char *)NewSlab, Alignment);
- assert((uintptr_t)Ptr + Size <= (uintptr_t)NewSlab + PaddedSize);
- __msan_allocated_memory(Ptr, Size);
- return Ptr;
+ 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();
- Ptr = alignPtr(CurPtr, Alignment);
- CurPtr = Ptr + Size;
- assert(CurPtr <= End && "Unable to allocate memory!");
- __msan_allocated_memory(Ptr, Size);
- return Ptr;
+ 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;
}
// Pull in base class overloads.
for (; I != E; ++I) {
size_t AllocatedSlabSize =
computeSlabSize(std::distance(Slabs.begin(), I));
-#ifndef NDEBUG
- // Poison the memory so stale pointers crash sooner. Note we must
- // preserve the Size and NextPtr fields at the beginning.
- sys::Memory::setRangeWritable(*I, AllocatedSlabSize);
- memset(*I, 0xCD, AllocatedSlabSize);
-#endif
Allocator.Deallocate(*I, AllocatedSlabSize);
}
}
for (auto &PtrAndSize : CustomSizedSlabs) {
void *Ptr = PtrAndSize.first;
size_t Size = PtrAndSize.second;
-#ifndef NDEBUG
- // Poison the memory so stale pointers crash sooner. Note we must
- // preserve the Size and NextPtr fields at the beginning.
- sys::Memory::setRangeWritable(Ptr, Size);
- memset(Ptr, 0xCD, Size);
-#endif
Allocator.Deallocate(Ptr, Size);
}
}
/// all memory allocated so far.
void DestroyAll() {
auto DestroyElements = [](char *Begin, char *End) {
- assert(Begin == alignPtr(Begin, alignOf<T>()));
+ assert(Begin == (char*)alignAddr(Begin, alignOf<T>()));
for (char *Ptr = Begin; Ptr + sizeof(T) <= End; Ptr += sizeof(T))
reinterpret_cast<T *>(Ptr)->~T();
};
++I) {
size_t AllocatedSlabSize = BumpPtrAllocator::computeSlabSize(
std::distance(Allocator.Slabs.begin(), I));
- char *Begin = alignPtr((char *)*I, alignOf<T>());
+ char *Begin = (char*)alignAddr(*I, alignOf<T>());
char *End = *I == Allocator.Slabs.back() ? Allocator.CurPtr
: (char *)*I + AllocatedSlabSize;
for (auto &PtrAndSize : Allocator.CustomSizedSlabs) {
void *Ptr = PtrAndSize.first;
size_t Size = PtrAndSize.second;
- DestroyElements(alignPtr((char *)Ptr, alignOf<T>()), (char *)Ptr + Size);
+ DestroyElements((char*)alignAddr(Ptr, alignOf<T>()), (char *)Ptr + Size);
}
Allocator.Reset();