Re-committing changes from r76825 to BumpPtrAllocator with a fix and tests for
an off-by-one error.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76891 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Support/AllocatorTest.cpp b/unittests/Support/AllocatorTest.cpp
index e69de29..cc3296a 100644
--- a/unittests/Support/AllocatorTest.cpp
+++ b/unittests/Support/AllocatorTest.cpp
@@ -0,0 +1,95 @@
+//===- 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());
+}
+
+// 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 dont't allocate a new slab, then we will have overflowed.
+ Alloc.Allocate(1, 0);
+ EXPECT_EQ(2U, Alloc.GetNumSlabs());
+}
+
+} // anonymous namespace