Iterative graph traversal in FlowGraph::DiscoverBlocks()

runtime/vm/flow_graph.h

Index: runtime/vm/flow_graph.h
diff --git a/runtime/vm/flow_graph.h b/runtime/vm/flow_graph.h
index 45d64a7f8e41b1be53e2418c4eb6ddca97780b8f..134cc5ac48b1ab20e2880f644afc5983284420e8 100644
--- a/runtime/vm/flow_graph.h
+++ b/runtime/vm/flow_graph.h
@@ -42,6 +42,17 @@ class BlockIterator : public ValueObject {
 };
 
 
+struct BlockEntryEdge {
+  BlockEntryEdge(BlockEntryInstr* parent, BlockEntryInstr* child)
+    : parent(parent),
+      child(child) { }
+  BlockEntryInstr* parent;
+  BlockEntryInstr* child;
+
+  DISALLOW_ALLOCATION();
+};
+
+
 struct ConstantPoolTrait {
   typedef ConstantInstr* Value;
   typedef const Object& Key;