Add support for allowing an embedder to get the V8 profile timer event logs.

src/log.h

Index: src/log.h
diff --git a/src/log.h b/src/log.h
index d4dc76a21cc5222139e209646505caf90534d16a..e5ba111de64bca624eafd9a348120b48532ee7b4 100644
--- a/src/log.h
+++ b/src/log.h
@@ -99,6 +99,13 @@ struct TickSample;
       logger->Call;                                 \
   } while (false)
 
+#define LOG_EVENT_BEGIN(isolate, name)              \
+  if ((isolate)->event_logger())                    \
+    (isolate)->event_logger()(name, 0)

[Sven Panne, 2014/03/05 07:47:29]

Parenthesize "name" and never ever use unbalanced "if"s in macros.
Alternatively: Why don't we just use an inline function instead of the macro?
This would be nicer...

[Yang, 2014/03/05 08:18:31]

Agree.

[fmeawad, 2014/03/06 00:24:46]

Moved to an inlined function in Patch 5, and totally removed in Patch 6.

+
+#define LOG_EVENT_END(isolate, name)                \
+  if ((isolate)->event_logger())                    \
+    (isolate)->event_logger()(name, 1)
 
 #define LOG_EVENTS_AND_TAGS_LIST(V)                                     \
   V(CODE_CREATION_EVENT,            "code-creation")                    \
@@ -320,11 +327,11 @@ class Logger {
    public:
     TimerEventScope(Isolate* isolate, const char* name)
         : isolate_(isolate), name_(name) {
-      if (FLAG_log_internal_timer_events) LogTimerEvent(START);
+      LogTimerEvent(START);

[Yang, 2014/03/05 08:18:31]

I'm concerned that this may regress performance since we call LogTimerEvent
(which is not inlined) even if the flag is off.

[fmeawad, 2014/03/06 00:24:46]

As you mentioned, I am only including those for the
Flag_log_internal_timer_events, which should not have a measurable overhead (I
am also excluding it from External).

     }
 
     ~TimerEventScope() {
-      if (FLAG_log_internal_timer_events) LogTimerEvent(END);
+      LogTimerEvent(END);
     }
 
     void LogTimerEvent(StartEnd se);