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Re: Apple's PFE for GCC is now available
- From: Daniel Berlin <dberlin at dberlin dot org>
- To: Mike Stump <mrs at apple dot com>
- Cc: Neil Booth <neil at daikokuya dot co dot uk>, Stan Shebs <shebs at apple dot com>,gcc at gcc dot gnu dot org
- Date: Wed, 31 Jul 2002 12:19:17 -0400
- Subject: Re: Apple's PFE for GCC is now available
On Wednesday, July 31, 2002, at 12:04 PM, Mike Stump wrote:
On Tuesday, July 30, 2002, at 11:43 PM, Neil Booth wrote:
Finally, if you're wondering how this relates to the PCH branch, it's
being actively discussed. PFE has both pluses and minuses relative
to
the current PCH work, and ideally we'll be able to use both in coming
up with superior precompiled header support for FSF GCC.
Where is it being actively discussed? It's a shame this stuff isn't
out in the open; I'd like to know what the plans are as I have (had)
ideas of my own.
This is the right place. This is the place where we are discussing it.
The plan is to make gcc/g+ 6x faster. Exactly how we do that, is up
for discussion. We have an initial implementation that gets us there
that we are using in our production compiler. If it meets the various
standards for the tree, would be nice to get it into the tree. Once
in, we can then refine it further.
(A note: I've been following PFE since it's existed in apple's tree, so
I'm intimately familiar with it.)
PFE's implementation, as it stands, is somewhat invasive, with the
GGC_ALLOC macro, etc.
While I understand many of these invasions are necessary to restore the
state properly (like intercepting the debug hooks), there is one
invasion that *should* be completely unnecessary if PFE was in the
mainline.
This is the new walker functions to freeze/thaw various allocated
structures.
These should be gengtype generated. It would reduce the size of the
changes needed for PFE by a large amount.
If gengtype can't do something you need it to do in order to be able to
produce the walker code, then please, point this out.
IIRC, it was Geoff's intention to use it for generating the walkers
necessary for PCH anyway.
Also, if people that are interested would grab a copy and try it out,
say on linux or apple boxes, find/fix problems, try it out and just
give feedback on the performance enhancement they see, say for GTK+,
mozilla or pick your favorite monster, that would help. Also, let us
know if it `feels' ready for prime time. Let us know if it breaks
your builds... Are there any problems with it that should be
addressed before it goes into the tree?
I'd really like to see the freeze/thaw walkers auto-generated before it
goes into the tree.