Partially annotate V8 for MemorySanitizer.

This is a part of https://codereview.chromium.org/26006004/.
These changes are enough to run most apps that embed V8 (by additionally
ignoring all memory accesses from V8), but don't help testing V8 itself in any
way.

R=danno@chromium.org

Review URL: https://codereview.chromium.org/27471003

Patch from Evgeniy Stepanov <eugenis@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17331 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/msan.h

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// MemorySanitizer support.
+
+#ifndef V8_MSAN_H_
+#define V8_MSAN_H_
+
+#ifndef __has_feature
+# define __has_feature(x) 0
+#endif
+
+#if __has_feature(memory_sanitizer)
+# define MEMORY_SANITIZER
+#endif
+
+#ifdef MEMORY_SANITIZER
+# include <sanitizer/msan_interface.h>
+// Marks a memory range as fully initialized.
+# define MSAN_MEMORY_IS_INITIALIZED(p, s) __msan_unpoison((p), (s))
+#else
+# define MSAN_MEMORY_IS_INITIALIZED(p, s)
+#endif
+
+#endif  // V8_MSAN_H_

src/spaces.cc

@@ -29,6 +29,7 @@
 
 #include "macro-assembler.h"
 #include "mark-compact.h"
+#include "msan.h"
 #include "platform.h"
 
 namespace v8 {
@@ -717,6 +718,7 @@ MemoryChunk* MemoryAllocator::AllocateChunk(intptr_t reserve_area_size,
                                                 executable,
                                                 owner);
   result->set_reserved_memory(&reservation);
+  MSAN_MEMORY_IS_INITIALIZED(base, chunk_size);
   return result;
 }