After moving unreachable weak global handles only process harmony collections

test/cctest/test-api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4365 matching lines @@
     iso->SetReferenceFromGroup(id4, g1s1.handle);
   }
 
   heap->CollectAllGarbage(i::Heap::kAbortIncrementalMarkingMask);
 
   // All objects should be gone. 9 global handles in total.
   CHECK_EQ(9, counter.NumberOfWeakCalls());
 }
 
 
+THREADED_TEST(WeakRootsSurviveTwoRoundsOfGC) {
+  LocalContext env;
+  v8::Isolate* iso = env->GetIsolate();
+  HandleScope scope(iso);
+
+  WeakCallCounter counter(1234);
+
+  WeakCallCounterAndPersistent<Value> weak_obj(&counter);
+
+  // Create a weak object that references a internalized string.
+  {
+    HandleScope scope(iso);
+    weak_obj.handle.Reset(iso, Object::New(iso));
+    weak_obj.handle.SetWeak(&weak_obj, &WeakPointerCallback);
+    CHECK(weak_obj.handle.IsWeak());
+    Local<Object>::New(iso, weak_obj.handle.As<Object>())->Set(
+        v8_str("x"),
+        String::NewFromUtf8(iso, "magic cookie", String::kInternalizedString));
+  }
+  // Do a single full GC
+  i::Isolate* i_iso = reinterpret_cast<v8::internal::Isolate*>(iso);
+  i::Heap* heap = i_iso->heap();
+  heap->CollectAllGarbage(i::Heap::kAbortIncrementalMarkingMask);
+
+  // We should have received the weak callback.
+  CHECK_EQ(1, counter.NumberOfWeakCalls());
+
+  // Check that the string is still alive.
+  {
+    HandleScope scope(iso);
+    i::MaybeHandle<i::String> magic_string =
+        i::StringTable::LookupStringIfExists(
+            i_iso,
+            v8::Utils::OpenHandle(*String::NewFromUtf8(iso, "magic cookie")));
+    magic_string.Check();
+  }
+}
+
+
 // TODO(mstarzinger): This should be a THREADED_TEST but causes failures
 // on the buildbots, so was made non-threaded for the time being.
 TEST(ApiObjectGroupsCycleForScavenger) {
   i::FLAG_stress_compaction = false;
   i::FLAG_gc_global = false;
   LocalContext env;
   v8::Isolate* iso = env->GetIsolate();
   HandleScope scope(iso);
 
   WeakCallCounter counter(1234);
@@ skipping 19986 matching lines @@
   v8::HandleScope scope(CcTest::isolate());
   RandomLengthOneByteResource* r =
       new RandomLengthOneByteResource(i::String::kMaxLength);
   v8::Local<v8::String> str = v8::String::NewExternal(CcTest::isolate(), r);
   CHECK(!str.IsEmpty());
   v8::TryCatch try_catch;
   v8::Local<v8::String> result = v8::String::Concat(str, str);
   CHECK(result.IsEmpty());
   CHECK(!try_catch.HasCaught());
 }