Apple's PFE for GCC is now available

[Daniel Berlin]

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.