This patch is the propagation version of https://codereview.chromium.org/10824032 patch

include/v8.h

 // Copyright 2012 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 3012 matching lines @@
 
 /**
  * A JIT code event is issued each time code is added, moved or removed.
  *
  * \note removal events are not currently issued.
  */
 struct JitCodeEvent {
   enum EventType {
     CODE_ADDED,
     CODE_MOVED,
-    CODE_REMOVED
+    CODE_REMOVED,
+    CODE_ADD_LINE_POS_INFO,
+    CODE_START_LINE_INFO_RECORDING,
+    CODE_END_LINE_INFO_RECORDING
   };
 
   // Type of event.
   EventType type;
   // Start of the instructions.
   void* code_start;
   // Size of the instructions.
   size_t code_len;
+  // Script info for CODE_ADDED event or line_info_struct
+  // for CODE_ADD_LINE_POS_INFO and CODE_END_LINE_INFO_RECORDING event
+  void* user_data;

[danno, 2013/01/10 16:47:33]

I don't think you saw my original comment completely: please strongly type where
possible, adding a "Handle<Script> script;" here as the script parameter. That's
the only thing that makes sense

In general, I think you have confused who should define/own JITCodeLineInfo. V8
should't define and manage that struct, instead, it should just call the client
providing information about the code events and let the event_handler decide
what to do with them. 

So here's how it should work.

1) The JITCodeLineInfo is defined *only* in your VTune/test code. 
2) V8 issues a CODE_START_LINE_INFO_RECORDING event to the event handler, which
creates a new JITCodeLineInfo and stores it's address in the user_data field of
the even.
3) V8 remembers the user_data field passed back from the event handler and
stores it in the PositionRecord
4) V8 issues CODE_ADD_LINE_POS_INFO events for each position record, passing the
user_data field back into the handler that it got with the
CODE_START_LINE_INFO_RECORDING event. The event handler casts this to a
JITCodeLineInfo and calls AddCodeLineInfo method on it.
5) When the code is done, V8 calls the event handler with the
CODE_END_LINE_INFO_RECORDING event, passing in user_data that it got from the
CODE_START_LINE_INFO_RECORDING event. The event handler casts this to a
JITCodeLineInfo and deletes it after processing the aggregate line info as it
sees fit.

[chunyang.dai, 2013/01/18 10:22:44]

Done.

 
   union {
     // Only valid for CODE_ADDED.
     struct {
       // Name of the object associated with the code, note that the string is
       // not zero-terminated.
       const char* str;
       // Number of chars in str.
       size_t len;
     } name;
+
+    // Only valid for CODE_ADD_LINE_POS_INFO
+    struct {
+      // PC offset
+      size_t offset;
+      // Code postion
+      size_t pos;
+      // Indicates whether this position is a "statement position". (as opposed
+      // to the "postion". See comment for RelocInfo::kNoPosition field.)
+      bool is_statement;

[danno, 2013/01/10 16:47:33]

please create an enum PositionType that can be either STATEMENT_POSITION or
POSITION.

[chunyang.dai, 2013/01/18 10:22:44]

Done.

+    } line_info;
+
     // New location of instructions. Only valid for CODE_MOVED.
     void* new_code_start;
   };
 };
 
 /**
  * Option flags passed to the SetJitCodeEventHandler function.
  */
 enum JitCodeEventOptions {
   kJitCodeEventDefault = 0,
@@ skipping 1800 matching lines @@
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_