JavaScript ActionMonkey
ActionMonkey is the code-name for the project to integrate Tamarin and SpiderMonkey as part of Mozilla 2.
Want to help? Write to jason dot orendorff at gmail dot com. Or visit [1] and say hi.
Goals
The goals are:
- Preservation (with necessary additions and as few deletions as possible) of jsapi.h.
- SpiderMonkey's thread safety and property tree integrated/reimplemented in Tamarin.
- Replacement of SpiderMonkey's decompiler with a better decompiler that can work with ABC.
- Replacement of SpiderMonkey's GC with Tamarin:MMgc, evolved as needed.
- Replacement of SpiderMonkey's interpreter by an evolved version of Tamarin's.
- Advanced JIT optimization for hot paths and untyped code, inspired by Trace Trees.
- Information flow VM support for better security models.
Stage 0
Replace SpiderMonkey's GC with Tamarin's GC (MMgc). See JavaScript:ActionMonkey:Stage 0 Whiteboard.
Work is underway in the http://hg.mozilla.org/actionmonkey and http://hg.mozilla.org/actionmonkey-tamarin Mercurial repositories. (The actionmonkey repo is a hard hat area, one step removed from the primary mozilla-central repository. This is because we expect things will break intermittently. Also because some of the people working on this aren't CVS committers yet, myself included. -jorendorff)
Stage 1
Integrate SpiderMonkey more closely with MMgc.
- Make MMgc::Mark() call SpiderMonkey trace() methods. The plan is to add a per-page type tag to MMgc; this takes over the job of the type bits in SpiderMonkey's GCThingFlags.
- Get rid of js_GetGCThingFlags.
- The type bits: move to an MMgc page-level type tag. (Note: The cycle collector sneakily uses these, in nsXPConnect.cpp; it will be changed.)
- The GCF_LOCK bit: mainly replaced by allowing MMgc to scan rt->gcLocksHash. There is also a string optimization that uses this bit. It's yet to be determined what to do about that.
- The GCF_MUTABLE bit: move into JSString.
- The GCF_SYSTEM bit: To be determined.
- Drop weak roots, newborns, and local root scopes (if they're not already gone in stage 0). These will be replaced by MMgc's conservative stack scanning.