Make StackContainer test pass on Android.

Failure output from experimental Android builder:
[ RUN      ] StackContainer.BufferAlignment
base/stack_container_unittest.cc:126: Failure
Value of: reinterpret_cast<uintptr_t>(&aligned256[0]) & (256 - 1)
  Actual: 80
Expected: 0u
Which is: 0
[  FAILED  ] StackContainer.BufferAlignment (1 ms)

BUG=115612

Review URL: http://codereview.chromium.org/9456032

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@124126 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 14 insertions, 2 deletions

diff --git a/base/stack_container.h b/base/stack_container.h
index 06ef2a4..e2db1c2 100644
--- a/base/stack_container.h
+++ b/base/stack_container.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "base/basictypes.h"
+#include "build/build_config.h"
 #include "base/memory/aligned_memory.h"
 
 // This allocator can be used with STL containers to provide a stack buffer
@@ -53,6 +54,9 @@ class StackAllocator : public std::allocator<T> {
     // constructors and destructors to be automatically called. Define a POD
     // buffer of the right size instead.
     base::AlignedMemory<sizeof(T[stack_capacity]), ALIGNOF(T)> stack_buffer_;
+#if defined(OS_ANDROID)
+    COMPILE_ASSERT(ALIGNOF(T) <= 16, crbug_115612);
+#endif
 
     // Set when the stack buffer is used for an allocation. We do not track
     // how much of the buffer is used, only that somebody is using it.
diff --git a/base/stack_container_unittest.cc b/base/stack_container_unittest.cc
index 175df36..798add7 100644
--- a/base/stack_container_unittest.cc
+++ b/base/stack_container_unittest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -121,9 +121,17 @@ TEST(StackContainer, BufferAlignment) {
   doubles->push_back(0.0);
   EXPECT_ALIGNED(&doubles[0], ALIGNOF(double));
 
+  StackVector<AlignedData<16>, 1> aligned16;
+  aligned16->push_back(AlignedData<16>());
+  EXPECT_ALIGNED(&aligned16[0], 16);
+
+#if !defined(OS_ANDROID)
+  // It seems that android doesn't respect greater than 16 byte alignment for
+  // non-POD data on the stack, even though ALIGNOF(aligned256) == 256.
   StackVector<AlignedData<256>, 1> aligned256;
   aligned256->push_back(AlignedData<256>());
   EXPECT_ALIGNED(&aligned256[0], 256);
+#endif
 }
 
 #ifdef COMPILER_MSVC