- Zap the allocated object when allocating uninitialized memory in debug.

runtime/vm/snapshot.cc

Index: runtime/vm/snapshot.cc
===================================================================
--- runtime/vm/snapshot.cc	(revision 32504)
+++ runtime/vm/snapshot.cc	(working copy)
@@ -723,6 +723,15 @@
     ErrorHandle()->set_exception(exception);
     Isolate::Current()->long_jump_base()->Jump(1, *ErrorHandle());
   }
+#if defined(DEBUG)
+  // Zap the uninitialized memory area.
+  uword current = address;
+  uword end = address + size;

[regis, 2014/02/10 17:49:05]

You could end at address + size - kWordSize, since the last word is initialized
to null.

+  while (current < end) {
+    *reinterpret_cast<intptr_t*>(current) = kZapUninitializedWord;
+    current += kWordSize;
+  }
+#endif  // defined(DBEUG)
   // Make sure to initialize the last word, as this can be left untouched in
   // case the object deserialized has an alignment tail.
   *reinterpret_cast<RawObject**>(address + size - kWordSize) = Object::null();