Verify/document assumption about stack resource addresses.

runtime/vm/allocation.cc

Index: runtime/vm/allocation.cc
===================================================================
--- runtime/vm/allocation.cc	(revision 43776)
+++ runtime/vm/allocation.cc	(working copy)
@@ -35,4 +35,20 @@
   return Allocate(size, zone);
 }
 
+
+void StackResource::Unwind(Isolate* isolate, uword stack_pointer) {
+  while (isolate->top_resource() != NULL &&
+         (reinterpret_cast<uword>(isolate->top_resource()) < stack_pointer)) {

[zra, 2015/02/17 19:45:24]

Should this be <= ?

[koda, 2015/02/17 20:01:15]

No, made it exclusive and documented that.

+    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 19:45:24]

Or should this be >= ?

Or is current == stack_pointer not possible?

If not possible please add a comment explaining why.

[koda, 2015/02/17 20:01:15]

With out current usage, it's not possible, since we pass in a stack pointer
that's between two C++ frames. However, for completeness, I've made this a ">="
and documented that it's exclusive (that's also consistent with the added
overloaded version of this method).

+    current = current->previous_;
+  }
+#endif  // DEBUG
+}
+
 }  // namespace dart