Verify/document assumption about stack resource addresses.

runtime/vm/exceptions.cc

Index: runtime/vm/exceptions.cc
===================================================================
--- runtime/vm/exceptions.cc	(revision 43776)
+++ runtime/vm/exceptions.cc	(working copy)
@@ -286,6 +286,14 @@
          (reinterpret_cast<uword>(isolate->top_resource()) < stack_pointer)) {
     isolate->top_resource()->~StackResource();
   }
+#if defined(DEBUG)
+  // All remaining stack resources should be below stack_pointer.
+  StackResource* current = isolate->top_resource();
+  while (current != NULL) {
+    ASSERT(reinterpret_cast<uword>(current) > stack_pointer);

[zra, 2015/02/17 19:00:23]

Is this the only place where this assertion is needed? Do we walk the stack
resources and reclaim anywhere else?

[koda, 2015/02/17 19:07:54]

Yes, we do the same thing in the simulators. We should share the code. I'll send
out an updated CL.

+    current = current->previous();
+  }
+#endif  // DEBUG
 
   // Call a stub to set up the exception object in kExceptionObjectReg,
   // to set up the stacktrace object in kStackTraceObjectReg, and to