669330 - Add static analysis check for the DOM Memory Reporter

Status: RESOLVED WONTFIX

Description

[Mounir Lamouri (:mounir)]

I think we could do something like:
1. Mark all classes participating to the DOM Memory Reporter;
2. Make sure these classes have a SizeOf() method;
3. Make sure this method call GetBasicSize() if the class inherits from something;
4. Mark attributes that are used to compute the size in SizeOf();
5. Make sure that all attributes that should be used in SizeOf() are marked.

Marking classes, could be done like NS_FINAL_CLASS or NS_STACK_CLASS.
I'm not sure marking attributes in the declaration is a good idea because what we want to catch is new attributes being added and very likely some people will just copy-paste the mark. In addition, marking attributes in the declaration might be a bit heavy and annoying to read. I think what could be a better idea is to put something inside SizeOf() to tell to the static analyzer which attributes are actually used in the method.

Comment 1

[Mounir Lamouri (:mounir)]

BTW, this solution isn't going to catch situations where object owning change and I don't think there is a simple way to do that.

Comment 2

[Nicholas Nethercote [:njn]]

FWIW, DMD (bug 676724) is a dynamic analysis tool that does very similar things to this bug.

Comment 3

[Andrew McCreight [:mccr8]]

DMD seems like enough of a backstop check for this.