Imported Upstream version 5.18.0.246

Former-commit-id: 0c7ce5b1a7851e13f22acfd379b7f9fb304e4833

external/llvm/unittests/Support/AllocatorTest.cpp

@@ -0,0 +1,188 @@
+//===- 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), alignof(int));
+  int *b = (int*)Alloc.Allocate(sizeof(int) * 10, alignof(int));
+  int *c = (int*)Alloc.Allocate(sizeof(int), alignof(int));
+  *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());
+
+  BumpPtrAllocator Alloc2 = std::move(Alloc);
+  EXPECT_EQ(0U, Alloc.GetNumSlabs());
+  EXPECT_EQ(1U, Alloc2.GetNumSlabs());
+
+  // Make sure the old pointers still work. These are especially interesting
+  // under ASan or Valgrind.
+  EXPECT_EQ(1, *a);
+  EXPECT_EQ(2, b[0]);
+  EXPECT_EQ(2, b[9]);
+  EXPECT_EQ(3, *c);
+
+  Alloc = std::move(Alloc2);
+  EXPECT_EQ(0U, Alloc2.GetNumSlabs());
+  EXPECT_EQ(1U, Alloc.GetNumSlabs());
+}
+
+// Allocate enough bytes to create three slabs.
+TEST(AllocatorTest, ThreeSlabs) {
+  BumpPtrAllocator Alloc;
+  Alloc.Allocate(3000, 1);
+  EXPECT_EQ(1U, Alloc.GetNumSlabs());
+  Alloc.Allocate(3000, 1);
+  EXPECT_EQ(2U, Alloc.GetNumSlabs());
+  Alloc.Allocate(3000, 1);
+  EXPECT_EQ(3U, Alloc.GetNumSlabs());
+}
+
+// Allocate enough bytes to create two slabs, reset the allocator, and do it
+// again.
+TEST(AllocatorTest, TestReset) {
+  BumpPtrAllocator Alloc;
+
+  // Allocate something larger than the SizeThreshold=4096.
+  (void)Alloc.Allocate(5000, 1);
+  Alloc.Reset();
+  // Calling Reset should free all CustomSizedSlabs.
+  EXPECT_EQ(0u, Alloc.GetNumSlabs());
+
+  Alloc.Allocate(3000, 1);
+  EXPECT_EQ(1U, Alloc.GetNumSlabs());
+  Alloc.Allocate(3000, 1);
+  EXPECT_EQ(2U, Alloc.GetNumSlabs());
+  Alloc.Reset();
+  EXPECT_EQ(1U, Alloc.GetNumSlabs());
+  Alloc.Allocate(3000, 1);
+  EXPECT_EQ(1U, Alloc.GetNumSlabs());
+  Alloc.Allocate(3000, 1);
+  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;
+
+  // Fill the slab right up until the end pointer.
+  Alloc.Allocate(4096, 1);
+  EXPECT_EQ(1U, Alloc.GetNumSlabs());
+
+  // If we don't allocate a new slab, then we will have overflowed.
+  Alloc.Allocate(1, 1);
+  EXPECT_EQ(2U, Alloc.GetNumSlabs());
+}
+
+// Test allocating with a size larger than the initial slab size.
+TEST(AllocatorTest, TestSmallSlabSize) {
+  BumpPtrAllocator Alloc;
+
+  Alloc.Allocate(8000, 1);
+  EXPECT_EQ(1U, Alloc.GetNumSlabs());
+}
+
+// Test requesting alignment that goes past the end of the current slab.
+TEST(AllocatorTest, TestAlignmentPastSlab) {
+  BumpPtrAllocator Alloc;
+  Alloc.Allocate(4095, 1);
+
+  // Aligning the current slab pointer is likely to move it past the end of the
+  // slab, which would confuse any unsigned comparisons with the difference of
+  // the end pointer and the aligned pointer.
+  Alloc.Allocate(1024, 8192);
+
+  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 {
+  static size_t LastSlabSize;
+
+public:
+  ~MockSlabAllocator() { }
+
+  void *Allocate(size_t Size, size_t /*Alignment*/) {
+    // 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*));
+
+    // Find the slab start.
+    void *Slab = (void *)alignAddr((char*)MemBase + sizeof(void *), Alignment);
+
+    // Hold a pointer to the base so we can free the whole malloced block.
+    ((void**)Slab)[-1] = MemBase;
+
+    LastSlabSize = Size;
+    return Slab;
+  }
+
+  void Deallocate(void *Slab, size_t Size) {
+    free(((void**)Slab)[-1]);
+  }
+
+  static size_t GetLastSlabSize() { return LastSlabSize; }
+};
+
+size_t MockSlabAllocator::LastSlabSize = 0;
+
+// 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) {
+  BumpPtrAllocatorImpl<MockSlabAllocator> Alloc;
+
+  // First allocate a tiny bit to ensure we have to re-align things.
+  (void)Alloc.Allocate(1, 1);
+
+  // Now the big chunk with a big alignment.
+  (void)Alloc.Allocate(3000, 2048);
+
+  // We test that the last slab size is not the default 4096 byte slab, but
+  // rather a custom sized slab that is larger.
+  EXPECT_GT(MockSlabAllocator::GetLastSlabSize(), 4096u);
+}
+
+}  // anonymous namespace