[unittest] Explicitly specify alignment when using BumpPtrAllocator.

[jordan_rose]

Summary

rL297310 began inserting red zones around allocations under ASan, which perturbs the alignment of subsequent allocations. Deliberately specify this in two places where it matters.

Fixes failures when these tests are run under ASan and UBSan together.

rdar://problem/30980047

[dexonsmith]

LGTM.

[jordan_rose]

Committed in rL297540.

unittests/Support/AllocatorTest.cpp

 #include <cstdlib>
 
 using namespace llvm;
 
 namespace {
 
 TEST(AllocatorTest, Basics) {
   BumpPtrAllocator Alloc;
-  int *a = (int*)Alloc.Allocate(sizeof(int), 1);
-  int *b = (int*)Alloc.Allocate(sizeof(int) * 10, 1);
-  int *c = (int*)Alloc.Allocate(sizeof(int), 1);
+  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);

unittests/Support/BinaryStreamTest.cpp

TEST_F(BinaryStreamTest, BinaryItemStream) {
 
   struct Foo {
     int X;
     double Y;
   };
   std::vector<Foo> Foos = {{1, 1.0}, {2, 2.0}, {3, 3.0}};
   BumpPtrAllocator Allocator;
   for (const auto &F : Foos) {
-    uint8_t *Ptr = Allocator.Allocate<uint8_t>(sizeof(Foo));
+    uint8_t *Ptr = static_cast<uint8_t *>(Allocator.Allocate(sizeof(Foo), 
+                                                             alignof(Foo)));
     MutableArrayRef<uint8_t> Buffer(Ptr, sizeof(Foo));
     MutableBinaryByteStream Stream(Buffer, llvm::support::big);
     BinaryStreamWriter Writer(Stream);
     ASSERT_NO_ERROR(Writer.writeObject(F));
     Objects.push_back(BinaryItemStreamObject(Buffer));
   }
 
   BinaryItemStream<BinaryItemStreamObject> ItemStream(big);