Fix OCaml bindings crash, PR8847.

[oota-llvm.git] / unittests / Support / AllocatorTest.cpp

diff --git a/unittests/Support/AllocatorTest.cpp b/unittests/Support/AllocatorTest.cpp
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..6c0fca90456e706ed7d2001d65a78845e9be3cb5 100644 (file)
--- a/unittests/Support/AllocatorTest.cpp
+++ b/unittests/Support/AllocatorTest.cpp
@@ -0,0 +1,143 @@
+//===- 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