Re: [plugin] Directory for plugins distributed with gcc

[Basile STARYNKEVITCH <basile at starynkevitch dot net>]

Joseph S. Myers wrote:
> On Wed, 15 Jul 2009, Paolo Bonzini wrote:
>
>   
> > On 07/15/2009 09:36 PM, Joseph S. Myers wrote:
> >     
> > > Before moving something out to a plugin (if we think that is technically
> > > appropriate for the particular code in question) we should have a way to
> > > build code, set up to be built as a plugin, into the compiler so that the
> > > -fplugin options find the built-in code, in a way that does not depend on
> > > plugins otherwise being supported on the host system; maybe somewhere in
> > > the source tree to put sources for plugins that get built into the
> > > compiler, or a configure option to point to such sources.
>
> Unless libltdl can be statically linked in, using it is a bad idea for 
> other reasons as previously discussed at length.
>
>   
I am aware of these reasons (but I am not sure to agree with them; 
however, that is not my point here) against libltdl.

A possible trick would be to decide a convention, such as a plugin whose 
name starts with a dot, or contains a slash, is in fact a "builtin" 
plugin, always available (and its code is part of GCC core). Actually, 
there is a reason to do so, if some GCC code wants to use some plugin 
facility. For instance, the MELT branch, even when compiled as a branch 
(i.e. without being compiled as a plugin), does call register_callback 
internally. And currently, code can call register_callback without any 
plugin being actually loaded in. There is no check on the plugin name 
argument to register_callback.
Such a convention (on builtin plugins) does not need to be implemented 
by code. It could be just agreed upon and suitably documented.

A side effect of this would be perhaps to limit extra GCC -f... program 
flags, since we could make them as plugin flags to builtin plugins.


Regards.

--
Basile STARYNKEVITCH         http://starynkevitch.net/Basile/
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