Wrong instance_size?

[hyj1991]

https://github.com/nodejs/llnode/blob/master/src/printer.cc#L489

If the map here is JS_MAP_TYPE, I think maybe the instance_size should be:

int64_t instance_size;
if (map.IsJSObjectMap(err)) {
  v8::HeapObject map_object = map.GetMap(err);
  v8::Map map(map_object);
  instance_size = map.InstanceSize(err);
} else {
  instance_size = map.InstanceSize(err);
}
if (err.Fail()) return std::string();

[mmarchini]

When the code gets here it should already be a v8::Map, but maybe we're missing some corner case here. JS_MAP_TYPE should fall under https://github.com/nodejs/llnode/blob/master/src/printer.cc#L655. Did you hit an issue with it? If so, can you share a small snippet with a reproducible (or more info)?

(JS_MAP_TYPE is https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map, right? If so, it's probably worth having a class dedicated for it)

[hyj1991]

@mmarchini Thanks for your reply :)

When the code gets here it should already be a v8::Map, but maybe we're missing some corner case here. JS_MAP_TYPE should fall under https://github.com/nodejs/llnode/blob/master/src/printer.cc#L655.

Indeed so. But if it already is a v8::Map, why should we judge here whether it is a js object map: https://github.com/nodejs/llnode/blob/master/src/printer.cc#L478

inline bool Map::IsJSObjectMap(Error& err) {
  return InstanceType(err) >= v8()->types()->kFirstJSObjectType;
}

kFirstJSObjectType is v8dbg_type_JSGlobalObject__JS_GLOBAL_OBJECT_TYPE (in reality JS_GLOBAL_OBJECT_TYPE), and I see JS_MAP_TYPE (src/objects/instance-type.h) is larger than JS_GLOBAL_OBJECT_TYPE, that's why I confused here.

(JS_MAP_TYPE is https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map, right? If so, it's probably worth having a class dedicated for it)

Indeed so.

[mmarchini]

I'll have to take a closer look to answer your questions (I'm going on vacation today, so I'll try to answer it when I'm back around late-Feb)

[hyj1991]

Thanks a lot :)