Introduce await

runtime/vm/parser.h

Index: runtime/vm/parser.h
diff --git a/runtime/vm/parser.h b/runtime/vm/parser.h
index b2fbfe64f738404fcdd7f834e1e90183c2e39638..c5b1b22da8c5ca449053fca2efeda55b9fbd203a 100644
--- a/runtime/vm/parser.h
+++ b/runtime/vm/parser.h
@@ -47,11 +47,14 @@ class ParsedFunction : public ZoneAllocated {
         saved_current_context_var_(NULL),
         saved_entry_context_var_(NULL),
         expression_temp_var_(NULL),
+        await_temps_scope_(NULL),
         deferred_prefixes_(new ZoneGrowableArray<const LibraryPrefix*>()),
         first_parameter_index_(0),
         first_stack_local_index_(0),
         num_copied_params_(0),
         num_stack_locals_(0),
+        num_awaits_(0),
+        seen_await_expr_(false),
         isolate_(isolate) {
     ASSERT(function.IsZoneHandle());
   }
@@ -123,6 +126,23 @@ class ParsedFunction : public ZoneAllocated {
 
   void AllocateVariables();
 
+  void set_await_temps_scope(LocalScope* scope) {
+    ASSERT(await_temps_scope_ == NULL);
+    await_temps_scope_ = scope;
+  }
+  LocalScope* await_temps_scope() const {
+    ASSERT(await_temps_scope_ != NULL);
+    return await_temps_scope_;
+  }
+
+  int num_awaits() const { return num_awaits_; }
+  void record_await() {
+    num_awaits_++;
+    seen_await_expr_ = true;
+  }
+  void reset_seen_await() { seen_await_expr_ = false; }
+  bool seen_await() const { return seen_await_expr_; }
+
   Isolate* isolate() const { return isolate_; }
 
  private:
@@ -134,12 +154,15 @@ class ParsedFunction : public ZoneAllocated {
   LocalVariable* saved_current_context_var_;
   LocalVariable* saved_entry_context_var_;
   LocalVariable* expression_temp_var_;
+  LocalScope* await_temps_scope_;
   ZoneGrowableArray<const LibraryPrefix*>* deferred_prefixes_;
 
   int first_parameter_index_;
   int first_stack_local_index_;
   int num_copied_params_;
   int num_stack_locals_;
+  int num_awaits_;
+  bool seen_await_expr_;
 
   Isolate* isolate_;
 
@@ -486,6 +509,7 @@ class Parser : public ValueObject {
   void OpenBlock();
   void OpenLoopBlock();
   void OpenFunctionBlock(const Function& func);
+  void OpenAsyncClosure();
   RawFunction* OpenAsyncFunction(intptr_t formal_param_pos);
   SequenceNode* CloseBlock();
   SequenceNode* CloseAsyncFunction(const Function& closure,
@@ -570,6 +594,9 @@ class Parser : public ValueObject {
   static const bool kAllowConst = false;
   static const bool kConsumeCascades = true;
   static const bool kNoCascades = false;
+  AstNode* ParseAwaitableExpr(bool require_compiletime_const,
+                              bool consume_cascades);
+  AstNode* ParseAwaitExpr();
   AstNode* ParseExpr(bool require_compiletime_const, bool consume_cascades);
   AstNode* ParseExprList();
   AstNode* ParseConditionalExpr();