Store Object.observe state per-isolate rather than per-context

src/runtime.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 13204 matching lines @@
 #undef ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_HaveSameMap) {
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSObject, obj1, 0);
   CONVERT_ARG_CHECKED(JSObject, obj2, 1);
   return isolate->heap()->ToBoolean(obj1->map() == obj2->map());
 }
 
+
+RUNTIME_FUNCTION(MaybeObject*, Runtime_GetObjectObservationState) {
+  ASSERT(args.length() == 0);
+  return isolate->heap()->object_observation_state();
+}
+
+
+RUNTIME_FUNCTION(MaybeObject*, Runtime_CreateObjectHashTable) {
+  ASSERT(args.length() == 0);
+  return ObjectHashTable::Allocate(0);

[Michael Starzinger, 2012/11/06 14:17:44]

As discussed offline, having this non-JS object escape into JavaScript (even
though we fully control the code) seems fishy. The clean solution would be to
wrap it into a JSValue, which is a full-fledged JSObject with one internal
field. That would add an additional indirection though.

But that would require quite some additional boilerplate and I am fine with
landing this as it is. Just wanted to leave this comment so that we can remember
there is a battle-plan if it ever hits us. I could very well imagine our fuzzer
generating tests that trigger this.

[adamk, 2012/11/06 14:54:21]

Noted. I'd also be fine with wrapping this in a JSValue right now, since the
indirection is likely going to be in the noise compared to the hash lookups, but
either way works for me.

+}
+
+
+RUNTIME_FUNCTION(MaybeObject*, Runtime_ObjectHashTableGet) {
+  NoHandleAllocation ha;
+  ASSERT(args.length() == 2);
+  ObjectHashTable* table = ObjectHashTable::cast(args[0]);

[Michael Starzinger, 2012/11/06 14:17:44]

Use the CONVERT_ARG_CHECKED macro here which will throw a proper exception upon
type mismatch. Otherwise our fuzzer might spot crashes when it fuzzes this
runtime function.

[adamk, 2012/11/06 14:54:21]

Done.

+  Object* key = args[1];
+  Object* lookup = table->Lookup(key);
+  return lookup->IsTheHole() ? isolate->heap()->undefined_value() : lookup;
+}
+
+
+RUNTIME_FUNCTION(MaybeObject*, Runtime_ObjectHashTableSet) {
+  HandleScope scope(isolate);
+  ASSERT(args.length() == 3);
+  Handle<ObjectHashTable> table = args.at<ObjectHashTable>(0);

[Michael Starzinger, 2012/11/06 14:17:44]

Likewise.

[adamk, 2012/11/06 14:54:21]

Done.

+  Handle<Object> key = args.at<Object>(1);
+  Handle<Object> value = args.at<Object>(2);
+  PutIntoObjectHashTable(table, key, value);
+  return isolate->heap()->undefined_value();
+}
+
+
+RUNTIME_FUNCTION(MaybeObject*, Runtime_ObjectHashTableHas) {
+  NoHandleAllocation ha;
+  ASSERT(args.length() == 2);
+  ObjectHashTable* table = ObjectHashTable::cast(args[0]);

[Michael Starzinger, 2012/11/06 14:17:44]

Likewise.

[adamk, 2012/11/06 14:54:21]

Done.

+  Object* key = args[1];
+  Object* lookup = table->Lookup(key);
+  return isolate->heap()->ToBoolean(!lookup->IsTheHole());
+}
+
+
 // ----------------------------------------------------------------------------
 // Implementation of Runtime
 
 #define F(name, number_of_args, result_size)                             \
   { Runtime::k##name, Runtime::RUNTIME, #name,   \
     FUNCTION_ADDR(Runtime_##name), number_of_args, result_size },
 
 
 #define I(name, number_of_args, result_size)                             \
   { Runtime::kInline##name, Runtime::INLINE,     \
@@ skipping 66 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal