LiveEdit: implement frame dropping

src/debug.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 359 matching lines @@
   static void AfterGarbageCollection();
 
   // Code generator routines.
   static void GenerateLoadICDebugBreak(MacroAssembler* masm);
   static void GenerateStoreICDebugBreak(MacroAssembler* masm);
   static void GenerateKeyedLoadICDebugBreak(MacroAssembler* masm);
   static void GenerateKeyedStoreICDebugBreak(MacroAssembler* masm);
   static void GenerateConstructCallDebugBreak(MacroAssembler* masm);
   static void GenerateReturnDebugBreak(MacroAssembler* masm);
   static void GenerateStubNoRegistersDebugBreak(MacroAssembler* masm);
+  static void GeneratePlainReturnLiveEdit(MacroAssembler* masm);
+  static void GenerateFrameDropperLiveEdit(MacroAssembler* masm);
 
   // Called from stub-cache.cc.
   static void GenerateCallICDebugBreak(MacroAssembler* masm);
 
+  static void FramesHaveBeenDropped(StackFrame::Id new_break_frame_id);
+
+  static void SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
+                                     Handle<Code> code);
+  static const int kFrameDropperFrameSize;
+
  private:
   static bool CompileDebuggerScript(int index);
   static void ClearOneShot();
   static void ActivateStepIn(StackFrame* frame);
   static void ClearStepIn();
   static void ActivateStepOut(StackFrame* frame);
   static void ClearStepOut();
   static void ClearStepNext();
   // Returns whether the compile succeeded.
   static void RemoveDebugInfo(Handle<DebugInfo> debug_info);
@@ skipping 45 matching lines @@
     // Frame pointer for frame from which step in was performed.
     Address step_into_fp_;
 
     // Frame pointer for the frame where debugger should be called when current
     // step out action is completed.
     Address step_out_fp_;
 
     // Storage location for jump when exiting debug break calls.
     Address after_break_target_;
 
+    // Indicates that LiveEdit has patched the stack.
+    bool frames_are_dropped_;
+
     // Top debugger entry.
     EnterDebugger* debugger_entry_;
 
     // Pending interrupts scheduled while debugging.
     int pending_interrupts_;
   };
 
   // Storage location for registers when handling debug break calls
   static JSCallerSavedBuffer registers_;
   static ThreadLocal thread_local_;
@@ skipping 432 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(MessageDispatchHelperThread);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 #endif  // V8_DEBUG_H_