Postpone counters triggered during GC, and use a HandleScope when calling back.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 54a8915788237436b72762d6cb303ed9f189725b..d5c8360c06e1cd3f4231970603ca16ef11bcb47a 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -395,6 +395,20 @@ void Heap::ReportStatisticsAfterGC() {
 #else
   if (FLAG_log_gc) new_space_.ReportStatistics();
 #endif  // DEBUG
+  for (int i = 0; i < static_cast<int>(v8::Isolate::kUseCounterFeatureCount);
+       ++i) {
+    int count = deferred_counters_[i];
+    deferred_counters_[i] = 0;
+    while (count != 0) {

[Jakob Kummerow, 2015/05/11 08:27:37]

nit: I'd suggest s/!=/>/ here, as it's slightly more accurate.

[Erik Corry, 2015/05/11 09:56:12]

Done.

+      count--;
+      isolate()->CountUsage(static_cast<v8::Isolate::UseCounterFeature>(i));
+    }
+  }
+}
+
+
+void Heap::IncrementDeferredCount(v8::Isolate::UseCounterFeature feature) {
+  deferred_counters_[feature]++;
 }
 
 
@@ -925,6 +939,11 @@ bool Heap::CollectGarbage(GarbageCollector collector, const char* gc_reason,
     tracer()->Stop(collector);
   }
 
+  if (collector == MARK_COMPACTOR &&
+      (gc_callback_flags & kGCCallbackFlagForced) != 0) {
+    isolate()->CountUsage(v8::Isolate::kForcedGC);
+  }
+
   // Start incremental marking for the next cycle. The heap snapshot
   // generator needs incremental marking to stay off after it aborted.
   if (!mark_compact_collector()->abort_incremental_marking() &&
@@ -5422,6 +5441,12 @@ bool Heap::SetUp() {
     }
   }
 
+  for (int i = 0; i < static_cast<int>(v8::Isolate::kUseCounterFeatureCount);
+       i++) {
+    deferred_counters_[i] = 0;
+  }
+
+
   LOG(isolate_, IntPtrTEvent("heap-capacity", Capacity()));
   LOG(isolate_, IntPtrTEvent("heap-available", Available()));