XPCOMGC

XPCOMGC is the Mozilla 2 project to convert the XPCOM object model from reference counting to use MMgc garbage collection.

General Info

TODO: collect/format information from the newsgroup discussion.

Add the request model threadsafety to MMgc bug 395962
Give MMgc the ability to recognize "inner" pointers to objects as typically used by C++ multiple inheritance bug 388070
Make the world depend on a common MMgc
Rewrite XPCOM addref/release handling
- Remove the cycle collector
- Use textual search/replace to remove most calls to NS_ADDREF/NS_RELEASE
- Use automatic finding to identify remaining references for manual cleanup
- Make all COM objects inherit from GCObject
- Rewrite nsCOMPtr+friends to be a lightweight wrapper for GC writebarriers
- Make stack pointers raw pointers
- Fix some COM-holding utility classes:
  - nsCOMArray
  - hashtables: nsInterfaceHashtable and nsInterfaceHashKey
- Rewrite XPCOM weakrefs to be GCWeakRefs
  - And remove those that can be regular GC references
Identify and deal with multi-threading, especially
- Initialize and suspend requests around blocking activity
- Analyze code for deadlock possibilities.
Set up a static checker based on GCC to enforce common invariants

The XPCOMGC work is currently taking place in mercurial patch queues on top of the ActionMonkey repositories: