Implemented "no heap access" mode for JSFrame which is used for stack sampling in profiler.

src/frames.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 355 matching lines @@
  private:
   friend class StackFrame;
 };
 
 
 class JavaScriptFrame: public StandardFrame {
  public:
   virtual Type type() const { return JAVA_SCRIPT; }
 
   // Accessors.
-  inline bool is_at_function() const;
   inline Object* function() const;
   inline Object* receiver() const;
   inline void set_receiver(Object* value);
 
   // Access the parameters.
   Object* GetParameter(int index) const;
   int ComputeParametersCount() const;
 
   // Temporary way of getting access to the number of parameters
   // passed on the stack by the caller. Once argument adaptor frames
@@ skipping 20 matching lines @@
   // Determine the code for the frame.
   virtual Code* code() const;
 
   static JavaScriptFrame* cast(StackFrame* frame) {
     ASSERT(frame->is_java_script());
     return static_cast<JavaScriptFrame*>(frame);
   }
 
  protected:
   explicit JavaScriptFrame(StackFrameIterator* iterator)
-      : StandardFrame(iterator) { }
+      : StandardFrame(iterator), disable_heap_access_(false) { }
 
   virtual Address GetCallerStackPointer() const;
 
+  // When this mode is enabled it is not allowed to access heap objects.
+  // This is a special mode used when gathering stack samples in profiler.
+  // A shortcoming is that caller's SP value will be calculated incorrectly

[iposva, 2009/04/13 23:16:09]

Is there a way where you can ASSERT if the caller's SP is accessed in this mode?

+  // (see GetCallerStackPointer implementation), but it is not used for stack
+  // sampling.
+  void DisableHeapAccess() { disable_heap_access_ = true; }
+
  private:
+  bool disable_heap_access_;
   inline Object* function_slot_object() const;
 
   friend class StackFrameIterator;
 };
 
 
 // Arguments adaptor frames are automatically inserted below
 // JavaScript frames when the actual number of parameters does not
 // match the formal number of parameters.
 class ArgumentsAdaptorFrame: public JavaScriptFrame {
@@ skipping 241 matching lines @@
   JavaScriptFrame* FindJavaScriptFrame(int n);
 
  private:
   StackFrameIterator iterator_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_FRAMES_H_