From 97e910ecff5ed8b653a07fb1d014dab772931c0b Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Thu, 1 Mar 2012 22:10:16 +0000 Subject: [PATCH] BumpPtrAllocator: Make sure threshold cannot be initialized with a value smaller than the slab size. This replaces r151834 with a simpler fix. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151842 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Support/Allocator.cpp | 17 ++++++----------- unittests/Support/AllocatorTest.cpp | 2 +- 2 files changed, 7 insertions(+), 12 deletions(-) diff --git a/lib/Support/Allocator.cpp b/lib/Support/Allocator.cpp index 8bb07405ec6..b8978302e74 100644 --- a/lib/Support/Allocator.cpp +++ b/lib/Support/Allocator.cpp @@ -22,8 +22,8 @@ namespace llvm { BumpPtrAllocator::BumpPtrAllocator(size_t size, size_t threshold, SlabAllocator &allocator) - : SlabSize(size), SizeThreshold(threshold), Allocator(allocator), - CurSlab(0), BytesAllocated(0) { } + : SlabSize(size), SizeThreshold(std::min(size, threshold)), + Allocator(allocator), CurSlab(0), BytesAllocated(0) { } BumpPtrAllocator::~BumpPtrAllocator() { DeallocateSlabs(CurSlab); @@ -87,21 +87,15 @@ void BumpPtrAllocator::Reset() { /// Allocate - Allocate space at the specified alignment. /// void *BumpPtrAllocator::Allocate(size_t Size, size_t Alignment) { - // 0-byte alignment means 1-byte alignment. - if (Alignment == 0) Alignment = 1; - - size_t PaddedSize = Size + sizeof(MemSlab) + Alignment - 1; - - // If requested size exceeds slab size, increase slab size. - while (PaddedSize > SlabSize) - SlabSize *= 2; - 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); @@ -112,6 +106,7 @@ void *BumpPtrAllocator::Allocate(size_t Size, size_t Alignment) { } // 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); diff --git a/unittests/Support/AllocatorTest.cpp b/unittests/Support/AllocatorTest.cpp index bc5bd3dc407..8b463c11dfc 100644 --- a/unittests/Support/AllocatorTest.cpp +++ b/unittests/Support/AllocatorTest.cpp @@ -98,7 +98,7 @@ TEST(AllocatorTest, TestSmallSlabSize) { BumpPtrAllocator Alloc(128); Alloc.Allocate(200, 0); - EXPECT_EQ(1U, Alloc.GetNumSlabs()); + EXPECT_EQ(2U, Alloc.GetNumSlabs()); } // Mock slab allocator that returns slabs aligned on 4096 bytes. There is no