diff options
Diffstat (limited to 'include/llvm/Support/Allocator.h')
-rw-r--r-- | include/llvm/Support/Allocator.h | 66 |
1 files changed, 35 insertions, 31 deletions
diff --git a/include/llvm/Support/Allocator.h b/include/llvm/Support/Allocator.h index 7a7e4c0..de31771 100644 --- a/include/llvm/Support/Allocator.h +++ b/include/llvm/Support/Allocator.h @@ -90,7 +90,10 @@ class MallocAllocator : public AllocatorBase<MallocAllocator> { public: void Reset() {} - void *Allocate(size_t Size, size_t /*Alignment*/) { return malloc(Size); } + LLVM_ATTRIBUTE_RETURNS_NONNULL void *Allocate(size_t Size, + size_t /*Alignment*/) { + return malloc(Size); + } // Pull in base class overloads. using AllocatorBase<MallocAllocator>::Allocate; @@ -116,8 +119,8 @@ void printBumpPtrAllocatorStats(unsigned NumSlabs, size_t BytesAllocated, /// \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. /// @@ -200,28 +203,24 @@ public: } /// \brief Allocate space at the specified alignment. - void *Allocate(size_t Size, size_t Alignment) { - if (!CurPtr) // Start a new slab if we haven't allocated one already. - StartNewSlab(); + 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; - // 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); + 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. @@ -230,19 +229,22 @@ public: 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. @@ -320,8 +322,10 @@ private: #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); + if (AllocatedSlabSize != 0) { + sys::Memory::setRangeWritable(*I, AllocatedSlabSize); + memset(*I, 0xCD, AllocatedSlabSize); + } #endif Allocator.Deallocate(*I, AllocatedSlabSize); } @@ -373,7 +377,7 @@ public: /// 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(); }; @@ -382,7 +386,7 @@ public: ++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; @@ -392,7 +396,7 @@ public: 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(); |