Preparse top-level functions in discardable zones

src/ast/ast.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_AST_AST_H_
 #define V8_AST_AST_H_
 
 #include "src/ast/ast-types.h"
 #include "src/ast/ast-value-factory.h"
 #include "src/ast/modules.h"
@@ skipping 3528 matching lines @@
   // Handles use of temporary zones when parsing inner function bodies.
   class BodyScope {
    public:
     BodyScope(AstNodeFactory* factory, Zone* temp_zone, bool use_temp_zone)
         : factory_(factory), prev_zone_(factory->zone_) {
       if (use_temp_zone) {
         factory->zone_ = temp_zone;
       }
     }
 
-    ~BodyScope() { factory_->zone_ = prev_zone_; }
+    void Reset() { factory_->zone_ = prev_zone_; }
+    ~BodyScope() { Reset(); }
 
    private:
     AstNodeFactory* factory_;
     Zone* prev_zone_;
   };
 
  private:
   // This zone may be deallocated upon returning from parsing a function body
   // which we can guarantee is not going to be compiled or have its AST
   // inspected.
@@ skipping 40 matching lines @@
                                     : NULL;                                   \
   }
 AST_NODE_LIST(DECLARE_NODE_FUNCTIONS)
 #undef DECLARE_NODE_FUNCTIONS
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_AST_H_