GCC internal re-architecture proposal

[Andrew MacLeod <amacleod@redhat.com>]

[ I foolishly sent this with the document as an attachment... hopefully 
it gets rejected and anyone interested can simply download the document 
from the wiki..]

Over the past couple of months, I've slowly been putting together an 
action plan to help modernize GCC's source base.  We've had various 
ideas put forth over the years, and a few of the more meritorious ones 
have been incorporated.  My primary goal is to disentangle the front end 
from the middle/back ends, giving us better control over their data 
structures.

The biggest challenge is having an executable plan which allows the 
source to be updated incrementally.   Ie, we need a way to get from 
'Here' to 'There' that does not impact ongoing normal activities, nor 
noticeably affect the performance of the compiler.  This is a huge 
effort and it will require a large time commitment on my part to see it 
through.

I've attached a link to a document which outlines my proposal. Since 
putting it together, I've performed a couple of actual file conversions 
(albeit minor ones) beyond the simple examples I used in the document 
from the original proof of concept.  I've been refining some of the 
actual implementation details and logged the various design decisions 
that I encounter for later discussions  This document is a work in 
progress, and should be considered a strategic guide rather than an 
implementation bible.

There will be a BOF at Cauldron for anyone interested in discussing 
aspects of this.  I should also have a list of the interesting issues 
I've encountered for discussion there.

Im on vacation for about half the time between now and Cauldron, so I 
wanted to get this out now.  As for a time line, I wont be able to get 
seriously started on it for a couple of months since I have the C11 
_Atomic and gimple-atomic implementations to get delivered. That gives 
us a reasonable amount of time to address concerns and sort out the 
overall approach as well other nitty gritty before any serious work 
commences.    Once underway, I expect there would be plenty to do for 
anyone else interesting in volunteering some time.

Here's the proposal document... happy reading! Feedback is welcome.

I hope this link will work  :-)...
http://gcc.gnu.org/wiki/AndrewMacLeod?action=AttachFile&do=view&target=gccrestructureplan2.1.odt

Highlander