plugin hooks

[Richard Guenther]

On Wed, Oct 28, 2009 at 8:34 PM, Basile STARYNKEVITCH
<basile@starynkevitch.net> wrote:
> Hello All
>
> Rafael Espindola wrote:
>>>
>>> I have a concrete example here: plugin-specific pragmas (see
>>> PLUGIN_REGISTER_PRAGMA on http://gcc.gnu.org/wiki/plugin%20hook for
>>> details)
>>>
>>> I have two imaginary use cases here.
>>
>
> There are not so imaginary. I am sure I will need plugin specific pragmas in
> 2010. I explained why. But I also told that it is more than one man-year
> effort to exhibit a realistic plugin needing PLUGIN_REGISTER_PRAGMA
>
>
>>> People won't even bother to make plugins if they
>>> > feel the set of hooks is blantly unsufficient. [They will either
>>> > experiment on their own GCC branch, or avoid GCC entirely, for instance
>>> > using LLVM instead]. But working on one's branch is much more painful
>>> > than coding a plugin!
>>
>> I don't see a chicken and egg problem. Your work on making the GC
>> accessible to plugins is a good example why it is not  :-)
>
> Honestly, the [enormous in my view] effort I did make to push that GGC
> related features into the trunk have been disproportionately important
> w.r.t. the result. My work on GGC plugin events is precisely a good example
> of why I need to anticipate my plugin needs.
>
>
>> Sorry, the point is precisely that they should be concrete :-)
>>
>> If you are actually coding a plugin and get to the stage "ok, now I
>> need a new hook", please send a patch adding the hook and a
>> description of what the plugin is trying to do.
>
>
> You are forgetting an important point in GCC.
>
> The majority of GCC users won't compile GCC. Actually, I have concrete
> experience that most GCC users are not even able (that is willing to make
> the effort) to compile it. They will use a GCC in some distributed *binary*
> form (e.g. the gcc-4.5 package of some future Ubuntu, Debian, ...
> distribution, released in mid 2010).
>
> So in christmas 2010, a recently released Ubuntu contains the gcc-4.5
> package (the compiler) and the gcc-dev-4.5 package (enough to compile a gcc
> 4.5 plugin).
>
> Now I (Basile) have developed a plugin by that time which will use a
> PLUGIN_REGISTER_PRAGMA. If I requires its users to compile a gcc-trunk
> (since only after mid 2010 will I be able to really demonstrate a valid use
> of PLUGIN_REGISTER_PRAGMA), nobody -I really think not a single person- will
> use my plugin. If my plugin runs on a standard 4.5 binary distribution of
> gcc, I might have a few users!
>
>
> I really think we should add more plugin hooks *now* for gcc-4.5. They
> really cannot wait the future 4.6 release (in 2011, 2012?), especially since

I don't agree at all.  Also I have the feeling that plugins will in
the end result
in less developers on the core GCC infrastructure and thus plugins are bad
for GCC.

Richard.