[Tracing] Fix inaccurate timer calculation in runtime statistics.

src/counters.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/counters.h"
 
 #include <iomanip>
 
 #include "src/base/platform/platform.h"
 #include "src/isolate.h"
@@ skipping 350 matching lines @@
 #undef RESET_COUNTER
 
 #define RESET_COUNTER(name) this->Handler_##name.Reset();
   FOR_EACH_HANDLER_COUNTER(RESET_COUNTER)
 #undef RESET_COUNTER
 
   in_use_ = true;
 }
 
 void RuntimeCallStats::Dump(v8::tracing::TracedValue* value) {
+  if (current_timer_ != NULL) {
+    current_timer_->Elapsed();
+  }

[Camillo Bruni, 2016/10/27 09:00:58]

Can you add the same call to RuntimeCallStats::Print() which suffers from the
same issue. 

This probably didn't matter so much since we only miss on some marginal values
from the few timers that are active once we actually print the runtime stats.

[lpy, 2016/10/27 16:59:21]

Done.

 #define DUMP_COUNTER(name) \
   if (this->name.count > 0) this->name.Dump(value);
   FOR_EACH_MANUAL_COUNTER(DUMP_COUNTER)
 #undef DUMP_COUNTER
 
 #define DUMP_COUNTER(name, nargs, result_size) \
   if (this->Runtime_##name.count > 0) this->Runtime_##name.Dump(value);
   FOR_EACH_INTRINSIC(DUMP_COUNTER)
 #undef DUMP_COUNTER
 
@@ skipping 10 matching lines @@
 #define DUMP_COUNTER(name) \
   if (this->Handler_##name.count > 0) this->Handler_##name.Dump(value);
   FOR_EACH_HANDLER_COUNTER(DUMP_COUNTER)
 #undef DUMP_COUNTER
 
   in_use_ = false;
 }
 
 }  // namespace internal
 }  // namespace v8