Await it!

runtime/vm/flow_graph_builder.h

Index: runtime/vm/flow_graph_builder.h
diff --git a/runtime/vm/flow_graph_builder.h b/runtime/vm/flow_graph_builder.h
index ad595691629ddf39b438dfef904c4b1becc811d3..e4a23fa5e014ae93941ecd42ad1ae35671789671 100644
--- a/runtime/vm/flow_graph_builder.h
+++ b/runtime/vm/flow_graph_builder.h
@@ -179,6 +179,13 @@ class FlowGraphBuilder: public ValueObject {
   void set_catch_try_index(intptr_t value) { catch_try_index_ = value; }
   intptr_t catch_try_index() const { return catch_try_index_; }
 
+  int32_t next_await_counter() { return jump_cnt_++; }

[srdjan, 2014/08/20 17:50:06]

Why does it need to be 32 bits (int32_t), could it be just intptr_t?

[Michael Lippautz (Google), 2014/08/20 20:56:06]

Done.

+

[hausner, 2014/08/20 19:47:48]

@srdjan: I am fine with int32_t. This value is not expected to be more than
single digit. Let's not burn 7 bytes on 64bit platforms. In fact, I think we
could use int16_t but we'd probably not save anything due to alignment of other
fields.

[Michael Lippautz (Google), 2014/08/20 20:56:06]

intptr_t it is

+  ZoneGrowableArray<intptr_t>* await_levels() const { return await_levels_; }
+  ZoneGrowableArray<JoinEntryInstr*>* await_joins() const {
+    return await_joins_;
+  }
+
   void AddCatchEntry(CatchBlockEntryInstr* entry);
 
   intptr_t num_copied_params() const {
@@ -267,6 +274,10 @@ class FlowGraphBuilder: public ValueObject {
   // Do not generate a different graph based on this flag.
   const bool is_optimizing_;
 
+  int32_t jump_cnt_;
+  ZoneGrowableArray<JoinEntryInstr*>* await_joins_;
+  ZoneGrowableArray<intptr_t>* await_levels_;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(FlowGraphBuilder);
 };
 
@@ -457,6 +468,11 @@ class EffectGraphVisitor : public AstNodeVisitor {
 
   void BuildLetTempExpressions(LetNode* node);
 
+  void BuildAwaitJump(const LocalVariable& continuation_result,
+                      const LocalVariable& old_ctx,
+                      const intptr_t old_ctx_level,
+                      JoinEntryInstr* target);
+
   Isolate* isolate() const { return owner()->isolate(); }
 
  private: