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;
64 Alloc.Allocate(3000, 1);
65 EXPECT_EQ(1U, Alloc.GetNumSlabs());
66 Alloc.Allocate(3000, 1);
67 EXPECT_EQ(2U, Alloc.GetNumSlabs());
69 EXPECT_EQ(1U, Alloc.GetNumSlabs());
70 Alloc.Allocate(3000, 1);
71 EXPECT_EQ(1U, Alloc.GetNumSlabs());
72 Alloc.Allocate(3000, 1);
73 EXPECT_EQ(2U, Alloc.GetNumSlabs());
76 // Test some allocations at varying alignments.
77 TEST(AllocatorTest, TestAlignment) {
78 BumpPtrAllocator Alloc;
80 a = (uintptr_t)Alloc.Allocate(1, 2);
82 a = (uintptr_t)Alloc.Allocate(1, 4);
84 a = (uintptr_t)Alloc.Allocate(1, 8);
86 a = (uintptr_t)Alloc.Allocate(1, 16);
87 EXPECT_EQ(0U, a & 15);
88 a = (uintptr_t)Alloc.Allocate(1, 32);
89 EXPECT_EQ(0U, a & 31);
90 a = (uintptr_t)Alloc.Allocate(1, 64);
91 EXPECT_EQ(0U, a & 63);
92 a = (uintptr_t)Alloc.Allocate(1, 128);
93 EXPECT_EQ(0U, a & 127);
96 // Test allocating just over the slab size. This tests a bug where before the
97 // allocator incorrectly calculated the buffer end pointer.
98 TEST(AllocatorTest, TestOverflow) {
99 BumpPtrAllocator Alloc;
101 // Fill the slab right up until the end pointer.
102 Alloc.Allocate(4096, 1);
103 EXPECT_EQ(1U, Alloc.GetNumSlabs());
105 // If we don't allocate a new slab, then we will have overflowed.
106 Alloc.Allocate(1, 1);
107 EXPECT_EQ(2U, Alloc.GetNumSlabs());
110 // Test allocating with a size larger than the initial slab size.
111 TEST(AllocatorTest, TestSmallSlabSize) {
112 BumpPtrAllocator Alloc;
114 Alloc.Allocate(8000, 1);
115 EXPECT_EQ(1U, Alloc.GetNumSlabs());
118 // Test requesting alignment that goes past the end of the current slab.
119 TEST(AllocatorTest, TestAlignmentPastSlab) {
120 BumpPtrAllocator Alloc;
121 Alloc.Allocate(4095, 1);
123 // Aligning the current slab pointer is likely to move it past the end of the
124 // slab, which would confuse any unsigned comparisons with the difference of
125 // the the end pointer and the aligned pointer.
126 Alloc.Allocate(1024, 8192);
128 EXPECT_EQ(2U, Alloc.GetNumSlabs());
131 // Mock slab allocator that returns slabs aligned on 4096 bytes. There is no
132 // easy portable way to do this, so this is kind of a hack.
133 class MockSlabAllocator {
134 static size_t LastSlabSize;
137 ~MockSlabAllocator() { }
139 void *Allocate(size_t Size, size_t /*Alignment*/) {
140 // Allocate space for the alignment, the slab, and a void* that goes right
142 size_t Alignment = 4096;
143 void *MemBase = malloc(Size + Alignment - 1 + sizeof(void*));
145 // Find the slab start.
146 void *Slab = (void *)alignAddr((char*)MemBase + sizeof(void *), Alignment);
148 // Hold a pointer to the base so we can free the whole malloced block.
149 ((void**)Slab)[-1] = MemBase;
155 void Deallocate(void *Slab, size_t Size) {
156 free(((void**)Slab)[-1]);
159 static size_t GetLastSlabSize() { return LastSlabSize; }
162 size_t MockSlabAllocator::LastSlabSize = 0;
164 // Allocate a large-ish block with a really large alignment so that the
165 // allocator will think that it has space, but after it does the alignment it
167 TEST(AllocatorTest, TestBigAlignment) {
168 BumpPtrAllocatorImpl<MockSlabAllocator> Alloc;
170 // First allocate a tiny bit to ensure we have to re-align things.
171 (void)Alloc.Allocate(1, 1);
173 // Now the big chunk with a big alignment.
174 (void)Alloc.Allocate(3000, 2048);
176 // We test that the last slab size is not the default 4096 byte slab, but
177 // rather a custom sized slab that is larger.
178 EXPECT_GT(MockSlabAllocator::GetLastSlabSize(), 4096u);
181 } // anonymous namespace