Re: dependency tee from c parser entities downto token

[Christopher Li <sparse@chrisli.org>]

On Fri, May 4, 2012 at 1:53 PM, Konrad Eisele <eiselekd@gmail.com> wrote:
> make C=2:
>
> original sparse:
> real    17m54.997s
> user    15m25.181s
> sys     2m11.281s
>
> decpp-sparse from "git clone git://git.code.sf.net/p/decpp/code decpp "
> real    18m29.748s
> user    16m18.155s
> sys     2m13.221s
>
> But decpp is not written with performance in common cases in mind.
> The 2 runs probably also depend on other factors too.
> I cant think that 4 bytes extra for each token can have a big impact,
> if I would implement it that way (it is not in decpp).

The deal breaker is not able to free token list if other program using
sparse don't need it. I believe that I have an alternative approach
allow you do want you want while keeping the impact to sparse
internal small. In my mind, that is straightly better than your
current patch. I can share more details if you found a missing link.

> I understand. Actually the code to demonstrate is
> git://git.code.sf.net/p/decpp/code , then do a
> $make
> $./shrinkc t1.c
> That is kind of the goal.
> And - it does require some  internal structure
> change. You dont get this kind of functionality
> for free. You have to be invasive, isnt this
> something that is obvious?. And in my view, it
> can come with penalty. The preprocessing stage

That doesn't mean that we should pay any penalty
for it. Especially I believe there is better alternative
approach to allow you do what you want and keep
the API clean. You need to be a little patient here
to understand my alternative suggestions. I did spend
some time here to come up with the approach to make
it works for you and keep myself happy about the internals.

You dismiss the my suggestion too eagerly without
considering how to make it work. You are pretty much saying,
"Nah, this is not going to work, I am calling in the big hammers."
You should at least consider it, point out where you think
it doesn't work, so that I can provide addition details how
to make it work. I did notice that I have some detail left out in
my suggestions, mostly due to time constrain to write it up.

Chris
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