Reland: [modules] Properly initialize declared variables.

src/parsing/parser.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PARSING_PARSER_H_
 #define V8_PARSING_PARSER_H_
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/parsing/parser-base.h"
@@ skipping 198 matching lines @@
   enum CompletionKind {
     kNormalCompletion,
     kThrowCompletion,
     kAbruptCompletion
   };
 
   Variable* NewTemporary(const AstRawString* name) {
     return scope()->NewTemporary(name);
   }
 
+  void PrepareGeneratorVariables(FunctionState* function_state);
+
   // Limit the allowed number of local variables in a function. The hard limit
   // is that offsets computed by FullCodeGenerator::StackOperand and similar
   // functions are ints, and they should not overflow. In addition, accessing
   // local variables creates user-controlled constants in the generated code,
   // and we don't want too much user-controlled memory inside the code (this was
   // the reason why this limit was introduced in the first place; see
   // https://codereview.chromium.org/7003030/ ).
   static const int kMaxNumFunctionLocals = 4194303;  // 2^22-1
 
   // Returns NULL if parsing failed.
@@ skipping 339 matching lines @@
   // Rewrite expressions that are not used as patterns
   V8_INLINE void RewriteNonPattern(bool* ok);
 
   V8_INLINE void QueueDestructuringAssignmentForRewriting(
       Expression* assignment);
   V8_INLINE void QueueNonPatternForRewriting(Expression* expr, bool* ok);
 
   friend class InitializerRewriter;
   void RewriteParameterInitializer(Expression* expr, Scope* scope);
 
+  Expression* BuildInitialYield(int pos, FunctionKind kind);
   Expression* BuildCreateJSGeneratorObject(int pos, FunctionKind kind);
   Expression* BuildResolvePromise(Expression* value, int pos);
   Expression* BuildRejectPromise(Expression* value, int pos);
   Variable* PromiseVariable();
 
   // Generic AST generator for throwing errors from compiled code.
   Expression* NewThrowError(Runtime::FunctionId function_id,
                             MessageTemplate::Template message,
                             const AstRawString* arg, int pos);
 
@@ skipping 502 matching lines @@
   int total_preparse_skipped_;
   HistogramTimer* pre_parse_timer_;
 
   bool parsing_on_main_thread_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_PARSER_H_