Simplify restoring of saved try contexts in async code by passing around the

runtime/vm/parser.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_PARSER_H_
 #define VM_PARSER_H_
 
 #include "include/dart_api.h"
 
 #include "platform/assert.h"
@@ skipping 610 matching lines @@
   // Parse finally block and create an AST for it.
   SequenceNode* ParseFinallyBlock(bool is_async,
                                   LocalVariable* exception_var,
                                   LocalVariable* stack_trace_var,
                                   LocalVariable* rethrow_exception_var,
                                   LocalVariable* rethrow_stack_trace_var);
   // Push try block onto the stack of try blocks in scope.
   void PushTry(Block* try_block);
   // Pop the inner most try block from the stack.
   TryStack* PopTry();
-  // Collect try block scopes and indices if await or yield is in try block.
-  void CheckAsyncOpInTryBlock(LocalScope** try_scope,
-                              int16_t* try_index,
-                              LocalScope** outer_try_scope,
-                              int16_t* outer_try_index) const;
+  // Collect saved try context variables if await or yield is in try block.
+  void CheckAsyncOpInTryBlock(
+      LocalVariable** saved_try_ctx,
+      LocalVariable** async_saved_try_ctx,
+      LocalVariable** outer_saved_try_ctx,
+      LocalVariable** outer_async_saved_try_ctx) const;
   // Add specified node to try block list so that it can be patched with
   // inlined finally code if needed.
   void AddNodeForFinallyInlining(AstNode* node);
   // Add the inlined finally block to the specified node.
   void AddFinallyBlockToNode(bool is_async,
                              AstNode* node,
                              InlinedFinallyNode* finally_node);
   AstNode* ParseTryStatement(String* label_name);
   RawAbstractType* ParseConstFinalVarOrType(
       ClassFinalizer::FinalizationKind finalization);
@@ skipping 216 matching lines @@
 
   // Indentation of parser trace.
   intptr_t trace_indent_;
 
   DISALLOW_COPY_AND_ASSIGN(Parser);
 };
 
 }  // namespace dart
 
 #endif  // VM_PARSER_H_