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

include/v8.h

Index: include/v8.h
===================================================================
--- include/v8.h	(revision 13276)
+++ include/v8.h	(working copy)
@@ -3030,7 +3030,10 @@
   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.
@@ -3039,6 +3042,9 @@
   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.
@@ -3049,6 +3055,18 @@
       // 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;
   };