Fix MSAN warning on simulator during cpu profiling.

src/frames.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/frames.h"
 
 #include <sstream>
 
 #include "src/ast/ast.h"
 #include "src/ast/scopeinfo.h"
@@ skipping 396 matching lines @@
 StackFrame::Type StackFrame::ComputeType(const StackFrameIteratorBase* iterator,
                                          State* state) {
   DCHECK(state->fp != NULL);
 
   if (!iterator->can_access_heap_objects_) {
     // TODO(titzer): "can_access_heap_objects" is kind of bogus. It really
     // means that we are being called from the profiler, which can interrupt
     // the VM with a signal at any arbitrary instruction, with essentially
     // anything on the stack. So basically none of these checks are 100%
     // reliable.
+#if defined(USE_SIMULATOR)
+    MSAN_MEMORY_IS_INITIALIZED(
+        state->fp + StandardFrameConstants::kContextOffset, kPointerSize);
+    MSAN_MEMORY_IS_INITIALIZED(
+        state->fp + StandardFrameConstants::kMarkerOffset, kPointerSize);
+#endif
     if (StandardFrame::IsArgumentsAdaptorFrame(state->fp)) {
       // An adapter frame has a special SMI constant for the context and
       // is not distinguished through the marker.
       return ARGUMENTS_ADAPTOR;
     }
     Object* marker =
         Memory::Object_at(state->fp + StandardFrameConstants::kMarkerOffset);
     if (marker->IsSmi()) {
       return static_cast<StackFrame::Type>(Smi::cast(marker)->value());
     } else {
@@ skipping 1230 matching lines @@
   for (StackFrameIterator it(isolate); !it.done(); it.Advance()) {
     StackFrame* frame = AllocateFrameCopy(it.frame(), zone);
     list.Add(frame, zone);
   }
   return list.ToVector();
 }
 
 
 }  // namespace internal
 }  // namespace v8