1 //===- llvm/unittest/Support/AllocatorTest.cpp - BumpPtrAllocator tests ---===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/Support/Allocator.h"
11 #include "gtest/gtest.h"
18 TEST(AllocatorTest, Basics) {
19 BumpPtrAllocator Alloc;
20 int *a = (int*)Alloc.Allocate(sizeof(int), 1);
21 int *b = (int*)Alloc.Allocate(sizeof(int) * 10, 1);
22 int *c = (int*)Alloc.Allocate(sizeof(int), 1);
31 EXPECT_EQ(1U, Alloc.GetNumSlabs());
33 BumpPtrAllocator Alloc2 = std::move(Alloc);
34 EXPECT_EQ(0U, Alloc.GetNumSlabs());
35 EXPECT_EQ(1U, Alloc2.GetNumSlabs());
37 // Make sure the old pointers still work. These are especially interesting
38 // under ASan or Valgrind.
44 Alloc = std::move(Alloc2);
45 EXPECT_EQ(0U, Alloc2.GetNumSlabs());
46 EXPECT_EQ(1U, Alloc.GetNumSlabs());
49 // Allocate enough bytes to create three slabs.
50 TEST(AllocatorTest, ThreeSlabs) {
51 BumpPtrAllocator Alloc;
52 Alloc.Allocate(3000, 1);
53 EXPECT_EQ(1U, Alloc.GetNumSlabs());
54 Alloc.Allocate(3000, 1);
55 EXPECT_EQ(2U, Alloc.GetNumSlabs());
56 Alloc.Allocate(3000, 1);
57 EXPECT_EQ(3U, Alloc.GetNumSlabs());
60 // Allocate enough bytes to create two slabs, reset the allocator, and do it
62 TEST(AllocatorTest, TestReset) {
63 BumpPtrAllocator Alloc;
65 // Allocate something larger than the SizeThreshold=4096.
66 (void)Alloc.Allocate(5000, 1);
68 // Calling Reset should free all CustomSizedSlabs.
69 EXPECT_EQ(0u, Alloc.GetNumSlabs());
71 Alloc.Allocate(3000, 1);
72 EXPECT_EQ(1U, Alloc.GetNumSlabs());
73 Alloc.Allocate(3000, 1);
74 EXPECT_EQ(2U, Alloc.GetNumSlabs());
76 EXPECT_EQ(1U, Alloc.GetNumSlabs());
77 Alloc.Allocate(3000, 1);
78 EXPECT_EQ(1U, Alloc.GetNumSlabs());
79 Alloc.Allocate(3000, 1);
80 EXPECT_EQ(2U, Alloc.GetNumSlabs());
83 // Test some allocations at varying alignments.
84 TEST(AllocatorTest, TestAlignment) {
85 BumpPtrAllocator Alloc;
87 a = (uintptr_t)Alloc.Allocate(1, 2);
89 a = (uintptr_t)Alloc.Allocate(1, 4);
91 a = (uintptr_t)Alloc.Allocate(1, 8);
93 a = (uintptr_t)Alloc.Allocate(1, 16);
94 EXPECT_EQ(0U, a & 15);
95 a = (uintptr_t)Alloc.Allocate(1, 32);
96 EXPECT_EQ(0U, a & 31);
97 a = (uintptr_t)Alloc.Allocate(1, 64);
98 EXPECT_EQ(0U, a & 63);
99 a = (uintptr_t)Alloc.Allocate(1, 128);
100 EXPECT_EQ(0U, a & 127);
103 // Test allocating just over the slab size. This tests a bug where before the
104 // allocator incorrectly calculated the buffer end pointer.
105 TEST(AllocatorTest, TestOverflow) {
106 BumpPtrAllocator Alloc;
108 // Fill the slab right up until the end pointer.
109 Alloc.Allocate(4096, 1);
110 EXPECT_EQ(1U, Alloc.GetNumSlabs());
112 // If we don't allocate a new slab, then we will have overflowed.
113 Alloc.Allocate(1, 1);
114 EXPECT_EQ(2U, Alloc.GetNumSlabs());
117 // Test allocating with a size larger than the initial slab size.
118 TEST(AllocatorTest, TestSmallSlabSize) {
119 BumpPtrAllocator Alloc;
121 Alloc.Allocate(8000, 1);
122 EXPECT_EQ(1U, Alloc.GetNumSlabs());
125 // Test requesting alignment that goes past the end of the current slab.
126 TEST(AllocatorTest, TestAlignmentPastSlab) {
127 BumpPtrAllocator Alloc;
128 Alloc.Allocate(4095, 1);
130 // Aligning the current slab pointer is likely to move it past the end of the
131 // slab, which would confuse any unsigned comparisons with the difference of
132 // the the end pointer and the aligned pointer.
133 Alloc.Allocate(1024, 8192);
135 EXPECT_EQ(2U, Alloc.GetNumSlabs());
138 // Mock slab allocator that returns slabs aligned on 4096 bytes. There is no
139 // easy portable way to do this, so this is kind of a hack.
140 class MockSlabAllocator {
141 static size_t LastSlabSize;
144 ~MockSlabAllocator() { }
146 void *Allocate(size_t Size, size_t /*Alignment*/) {
147 // Allocate space for the alignment, the slab, and a void* that goes right
149 size_t Alignment = 4096;
150 void *MemBase = malloc(Size + Alignment - 1 + sizeof(void*));
152 // Find the slab start.
153 void *Slab = (void *)alignAddr((char*)MemBase + sizeof(void *), Alignment);
155 // Hold a pointer to the base so we can free the whole malloced block.
156 ((void**)Slab)[-1] = MemBase;
162 void Deallocate(void *Slab, size_t Size) {
163 free(((void**)Slab)[-1]);
166 static size_t GetLastSlabSize() { return LastSlabSize; }
169 size_t MockSlabAllocator::LastSlabSize = 0;
171 // Allocate a large-ish block with a really large alignment so that the
172 // allocator will think that it has space, but after it does the alignment it
174 TEST(AllocatorTest, TestBigAlignment) {
175 BumpPtrAllocatorImpl<MockSlabAllocator> Alloc;
177 // First allocate a tiny bit to ensure we have to re-align things.
178 (void)Alloc.Allocate(1, 1);
180 // Now the big chunk with a big alignment.
181 (void)Alloc.Allocate(3000, 2048);
183 // We test that the last slab size is not the default 4096 byte slab, but
184 // rather a custom sized slab that is larger.
185 EXPECT_GT(MockSlabAllocator::GetLastSlabSize(), 4096u);
188 } // anonymous namespace