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

src/isolate.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 <stdlib.h>
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
 
 #include "src/v8.h"
@@ skipping 2651 matching lines @@
 }
 
 
 void Isolate::SetUseCounterCallback(v8::Isolate::UseCounterCallback callback) {
   DCHECK(!use_counter_callback_);
   use_counter_callback_ = callback;
 }
 
 
 void Isolate::CountUsage(v8::Isolate::UseCounterFeature feature) {
-  if (use_counter_callback_) {
-    use_counter_callback_(reinterpret_cast<v8::Isolate*>(this), feature);
+  // The counter callback may cause the embedder to call into V8, which is not
+  // generally possible during GC.
+  if (heap_.gc_state() == Heap::NOT_IN_GC) {
+    if (use_counter_callback_) {
+      HandleScope handle_scope(this);
+      use_counter_callback_(reinterpret_cast<v8::Isolate*>(this), feature);
+    }
+  } else {
+    heap_.IncrementDeferredCount(feature);
   }
 }
 
 
 BasicBlockProfiler* Isolate::GetOrCreateBasicBlockProfiler() {
   if (basic_block_profiler_ == NULL) {
     basic_block_profiler_ = new BasicBlockProfiler();
   }
   return basic_block_profiler_;
 }
@@ skipping 91 matching lines @@
   if (prev_ && prev_->Intercept(flag)) return true;
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 } }  // namespace v8::internal