Rework flow graph construction.

src/compiler.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 120 matching lines @@
       return script_;
     } else {
       ASSERT(shared_info()->script()->IsScript());
       return Handle<Script>(Script::cast(shared_info()->script()));
     }
   }
 
   // There should always be a function literal, but it may be set after
   // construction (for lazy compilation).
   FunctionLiteral* function() { return function_; }
-  void set_function(FunctionLiteral* literal) {
-    ASSERT(function_ == NULL);
-    function_ = literal;
-  }
+  void set_function(FunctionLiteral* literal) { function_ = literal; }
 
   // Simple accessors.
   bool is_eval() { return is_eval_; }
   int loop_nesting() { return loop_nesting_; }
   bool has_receiver() { return !receiver_.is_null(); }
   Handle<Object> receiver() { return receiver_; }
   List<Bailout*>* bailouts() { return &bailouts_; }
 
   // Accessors for mutable fields (possibly set by analysis passes) with
   // default values given by Initialize.
@@ skipping 138 matching lines @@
       FrameElement::ClearConstantList();
       Result::ClearConstantList();
     }
   }
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_COMPILER_H_