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//===- llvm/unittest/Support/AllocatorTest.cpp - BumpPtrAllocator tests ---===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#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), 0);
int *b = (int*)Alloc.Allocate(sizeof(int) * 10, 0);
int *c = (int*)Alloc.Allocate(sizeof(int), 0);
*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());
}
// Allocate enough bytes to create three slabs.
TEST(AllocatorTest, ThreeSlabs) {
BumpPtrAllocator Alloc(4096, 4096);
Alloc.Allocate(3000, 0);
EXPECT_EQ(1U, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 0);
EXPECT_EQ(2U, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 0);
EXPECT_EQ(3U, Alloc.GetNumSlabs());
}
// Allocate enough bytes to create two slabs, reset the allocator, and do it
// again.
TEST(AllocatorTest, TestReset) {
BumpPtrAllocator Alloc(4096, 4096);
Alloc.Allocate(3000, 0);
EXPECT_EQ(1U, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 0);
EXPECT_EQ(2U, Alloc.GetNumSlabs());
Alloc.Reset();
EXPECT_EQ(1U, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 0);
EXPECT_EQ(1U, Alloc.GetNumSlabs());
Alloc.Allocate(3000, 0);
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(4096, 4096);
// Fill the slab right up until the end pointer.
Alloc.Allocate(4096 - sizeof(MemSlab), 0);
EXPECT_EQ(1U, Alloc.GetNumSlabs());
// If we don't allocate a new slab, then we will have overflowed.
Alloc.Allocate(1, 0);
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 : public SlabAllocator {
MemSlab *LastSlab;
public:
virtual ~MockSlabAllocator() { }
virtual MemSlab *Allocate(size_t Size) {
// Allocate space for the alignment, the slab, and a void* that goes right
// before the slab.
size_t Alignment = 4096;
void *MemBase = malloc(Size + Alignment - 1 + sizeof(void*));
// Make the slab.
MemSlab *Slab = (MemSlab*)(((uintptr_t)MemBase+sizeof(void*)+Alignment-1) &
~(uintptr_t)(Alignment - 1));
Slab->Size = Size;
Slab->NextPtr = 0;
// Hold a pointer to the base so we can free the whole malloced block.
((void**)Slab)[-1] = MemBase;
LastSlab = Slab;
return Slab;
}
virtual void Deallocate(MemSlab *Slab) {
free(((void**)Slab)[-1]);
}
MemSlab *GetLastSlab() {
return LastSlab;
}
};
// 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) {
MockSlabAllocator SlabAlloc;
BumpPtrAllocator Alloc(4096, 4096, SlabAlloc);
uintptr_t Ptr = (uintptr_t)Alloc.Allocate(3000, 2048);
MemSlab *Slab = SlabAlloc.GetLastSlab();
EXPECT_LE(Ptr + 3000, ((uintptr_t)Slab) + Slab->Size);
}
} // anonymous namespace
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