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//===- llvm/unittest/Support/AllocatorTest.cpp - BumpPtrAllocator tests ---===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Allocator.h"
#include "gtest/gtest.h"
#include <cstdlib>
using namespace llvm;
namespace {
TEST(AllocatorTest, Basics) {
BumpPtrAllocator Alloc;
int *a = (int*)Alloc.Allocate(sizeof(int), alignof(int));
int *b = (int*)Alloc.Allocate(sizeof(int) * 10, alignof(int));
int *c = (int*)Alloc.Allocate(sizeof(int), alignof(int));
*a = 1;
b[0] = 2;
b[9] = 2;
*c = 3;
EXPECT_EQ(1, *a);
EXPECT_EQ(2, b[0]);
EXPECT_EQ(2, b[9]);
EXPECT_EQ(3, *c);
EXPECT_EQ(1U, Alloc.GetNumSlabs());
BumpPtrAllocator Alloc2 = std::move(Alloc);
EXPECT_EQ(0U, Alloc.GetNumSlabs());
EXPECT_EQ(1U, Alloc2.GetNumSlabs());
// Make sure the old pointers still work. These are especially interesting
// under ASan or Valgrind.
EXPECT_EQ(1, *a);
EXPECT_EQ(2, b[0]);
EXPECT_EQ(2, b[9]);
EXPECT_EQ(3, *c);
Alloc = std::move(Alloc2);
EXPECT_EQ(0U, Alloc2.GetNumSlabs());
EXPECT_EQ(1U, Alloc.GetNumSlabs());
}
// Allocate enough bytes to create three slabs.
TEST(AllocatorTest, ThreeSlabs) {
BumpPtrAllocator Alloc;
Alloc.Allocate(3000, 1);
EXPECT_EQ(1U, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 1);
EXPECT_EQ(2U, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 1);
EXPECT_EQ(3U, Alloc.GetNumSlabs());
}
// Allocate enough bytes to create two slabs, reset the allocator, and do it
// again.
TEST(AllocatorTest, TestReset) {
BumpPtrAllocator Alloc;
// Allocate something larger than the SizeThreshold=4096.
(void)Alloc.Allocate(5000, 1);
Alloc.Reset();
// Calling Reset should free all CustomSizedSlabs.
EXPECT_EQ(0u, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 1);
EXPECT_EQ(1U, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 1);
EXPECT_EQ(2U, Alloc.GetNumSlabs());
Alloc.Reset();
EXPECT_EQ(1U, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 1);
EXPECT_EQ(1U, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 1);
EXPECT_EQ(2U, Alloc.GetNumSlabs());
}
// Test some allocations at varying alignments.
TEST(AllocatorTest, TestAlignment) {
BumpPtrAllocator Alloc;
uintptr_t a;
a = (uintptr_t)Alloc.Allocate(1, 2);
EXPECT_EQ(0U, a & 1);
a = (uintptr_t)Alloc.Allocate(1, 4);
EXPECT_EQ(0U, a & 3);
a = (uintptr_t)Alloc.Allocate(1, 8);
EXPECT_EQ(0U, a & 7);
a = (uintptr_t)Alloc.Allocate(1, 16);
EXPECT_EQ(0U, a & 15);
a = (uintptr_t)Alloc.Allocate(1, 32);
EXPECT_EQ(0U, a & 31);
a = (uintptr_t)Alloc.Allocate(1, 64);
EXPECT_EQ(0U, a & 63);
a = (uintptr_t)Alloc.Allocate(1, 128);
EXPECT_EQ(0U, a & 127);
}
// Test allocating just over the slab size. This tests a bug where before the
// allocator incorrectly calculated the buffer end pointer.
TEST(AllocatorTest, TestOverflow) {
BumpPtrAllocator Alloc;
// Fill the slab right up until the end pointer.
Alloc.Allocate(4096, 1);
EXPECT_EQ(1U, Alloc.GetNumSlabs());
// If we don't allocate a new slab, then we will have overflowed.
Alloc.Allocate(1, 1);
EXPECT_EQ(2U, Alloc.GetNumSlabs());
}
// Test allocating with a size larger than the initial slab size.
TEST(AllocatorTest, TestSmallSlabSize) {
BumpPtrAllocator Alloc;
Alloc.Allocate(8000, 1);
EXPECT_EQ(1U, Alloc.GetNumSlabs());
}
// Test requesting alignment that goes past the end of the current slab.
TEST(AllocatorTest, TestAlignmentPastSlab) {
BumpPtrAllocator Alloc;
Alloc.Allocate(4095, 1);
// Aligning the current slab pointer is likely to move it past the end of the
// slab, which would confuse any unsigned comparisons with the difference of
// the end pointer and the aligned pointer.
Alloc.Allocate(1024, 8192);
EXPECT_EQ(2U, Alloc.GetNumSlabs());
}
// Mock slab allocator that returns slabs aligned on 4096 bytes. There is no
// easy portable way to do this, so this is kind of a hack.
class MockSlabAllocator {
static size_t LastSlabSize;
public:
~MockSlabAllocator() { }
void *Allocate(size_t Size, size_t /*Alignment*/) {
// Allocate space for the alignment, the slab, and a void* that goes right
// before the slab.
size_t Alignment = 4096;
void *MemBase = safe_malloc(Size + Alignment - 1 + sizeof(void*));
// Find the slab start.
void *Slab = (void *)alignAddr((char*)MemBase + sizeof(void *), Alignment);
// Hold a pointer to the base so we can free the whole malloced block.
((void**)Slab)[-1] = MemBase;
LastSlabSize = Size;
return Slab;
}
void Deallocate(void *Slab, size_t Size) {
free(((void**)Slab)[-1]);
}
static size_t GetLastSlabSize() { return LastSlabSize; }
};
size_t MockSlabAllocator::LastSlabSize = 0;
// Allocate a large-ish block with a really large alignment so that the
// allocator will think that it has space, but after it does the alignment it
// will not.
TEST(AllocatorTest, TestBigAlignment) {
BumpPtrAllocatorImpl<MockSlabAllocator> Alloc;
// First allocate a tiny bit to ensure we have to re-align things.
(void)Alloc.Allocate(1, 1);
// Now the big chunk with a big alignment.
(void)Alloc.Allocate(3000, 2048);
// We test that the last slab size is not the default 4096 byte slab, but
// rather a custom sized slab that is larger.
EXPECT_GT(MockSlabAllocator::GetLastSlabSize(), 4096u);
}
} // anonymous namespace
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