Parameterize the BumpPtrAllocator over a slab allocator. It defaults to using

malloc, so there should be no functional changes to other code.

These changes are necessary since I have plans to use this allocator in the JIT
memory manager, and it needs a special allocator.

I also added some tests which helped me pinpoint some bugs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76825 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/Support/AllocatorTest.cpp

@@ -0,0 +1,61 @@
+//===- 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"
+
+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());
+}
+
+}  // anonymous namespace