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

include/v8.h

Index: include/v8.h
===================================================================
--- include/v8.h	(revision 13419)
+++ include/v8.h	(working copy)
@@ -3012,8 +3012,17 @@
   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
   };
+  // Definition of the code position type. See comment for
+  // RelocInfo::kNoPosition field.
+  enum PositionType {
+    POSITION,
+    STATEMENT_POSITION
+  };
 
   // Type of event.
   EventType type;
@@ -3021,6 +3030,11 @@
   void* code_start;
   // Size of the instructions.
   size_t code_len;
+  // Script info for CODE_ADDED event.
+  Handle<Script> script;
+  // User-defined data for other events. For example, the line_info_struct
+  // for CODE_ADD_LINE_POS_INFO and CODE_END_LINE_INFO_RECORDING event
+  void* user_data;
 
   union {
     // Only valid for CODE_ADDED.
@@ -3031,6 +3045,17 @@
       // 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;
+      // The position type.
+      PositionType position_type;
+    } line_info;
+
     // New location of instructions. Only valid for CODE_MOVED.
     void* new_code_start;
   };
@@ -3346,6 +3371,8 @@
    * \param options options for the JIT code event handler.
    * \param event_handler the JIT code event handler, which will be invoked
    *     each time code is added, moved or removed.
+   * \param support_moved_code the code move event is support or not. If it's
+   *     not enabled, the code will NOT be compacted during GC.
    * \note \p event_handler won't get notified of existent code.
    * \note since code removal notifications are not currently issued, the
    *     \p event_handler may get notifications of code that overlaps earlier
@@ -3360,7 +3387,8 @@
    *     it does not recognize to maintain future compatibility.
    */
   static void SetJitCodeEventHandler(JitCodeEventOptions options,
-                                     JitCodeEventHandler event_handler);
+                                     JitCodeEventHandler event_handler,
+                                     bool support_moved_code);

[danno, 2013/02/01 13:43:10]

Id like to avoid baking this into an API. Instead, you should make sure that you
call SetFlagsFromString in V8.h when you install your JIT code handler (or
before, for that matter, specifying the following flag: "--nocompact_code_space"
Middle-term, however, it would be very nice if you support movement in the code
space and remove this restriction.

 
   /**
    * Adjusts the amount of registered external memory.  Used to give