[debugging] Add %Verify() helper and check verify a HeapObject has a Map.

src/objects-debug.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/objects.h"
 
 #include "src/bootstrapper.h"
 #include "src/disasm.h"
 #include "src/disassembler.h"
 #include "src/field-type.h"
@@ skipping 26 matching lines @@
 
 
 void Smi::SmiVerify() {
   CHECK(IsSmi());
   CHECK(!IsCallable());
   CHECK(!IsConstructor());
 }
 
 
 void HeapObject::HeapObjectVerify() {
+  VerifyHeapPointer(map());
+  CHECK(map()->IsMap());
   InstanceType instance_type = map()->instance_type();
 
   if (instance_type < FIRST_NONSTRING_TYPE) {
     String::cast(this)->StringVerify();
     return;
   }
 
   switch (instance_type) {
     case SYMBOL_TYPE:
       Symbol::cast(this)->SymbolVerify();
@@ skipping 1505 matching lines @@
 
   // Both are done at the same time.
   CHECK_EQ(new_it.done(), old_it.done());
 }
 
 
 #endif  // DEBUG
 
 }  // namespace internal
 }  // namespace v8