llvm-ar: Clean up memory management with OwningPtr.

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

diff --git a/unittests/Support/AllocatorTest.cpp b/unittests/Support/AllocatorTest.cpp
index 139270b185f71c644c5c9bbaab2077aa1068f515..cb9fa430369b7231dde61507b31dff6da9314a8f 100644 (file)
--- a/unittests/Support/AllocatorTest.cpp
+++ b/unittests/Support/AllocatorTest.cpp
@@ -8,8 +8,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/Allocator.h"
-
 #include "gtest/gtest.h"
+#include <cstdlib>
 
 using namespace llvm;
 
@@ -58,4 +58,93 @@ TEST(AllocatorTest, TestReset) {
   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());
+}
+
+// Test allocating with a size larger than the initial slab size.
+TEST(AllocatorTest, TestSmallSlabSize) {
+  BumpPtrAllocator Alloc(128);
+
+  Alloc.Allocate(200, 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