Re: Progress on GCC plugins ?

[Taras Glek <taras.judge@shaw.ca>]

Tom Tromey wrote:
>>>>>> "Alexandre" == Alexandre Oliva <aoliva@redhat.com> writes:
>>>>>>             
>
> Alexandre> And then, once the underlying problem is addressed and we
> Alexandre> have an API that is usable by regular users, maybe we will
> Alexandre> find out that we don't need plugins, after all.
>
> Plugins are about deployment, not development.
>
> Plugins make it possible to redistribute useful things which are not
> in GCC.  They don't -- and as you rightly point out, can't -- make it
> simpler to actually develop these things.
>   
> The canonical example, which has been covered many times, is a pass
> that does extra checking for a large program (e.g., Mozilla).
>   
There are a lot of checks that could be implemented as plugins to 
benefit Mozilla and other projects. For future Mozilla development 
certain features that we are looking at are not feasible in C++ until 
the compiler can help with enforcing correct API usage. It would be 
extremely awesome to be able to utilize GCC internals for static 
analysis and source refactoring. Currently that isn't realistic as these 
features do not belong in the GCC mainline and distributing a gcc fork 
would be very burdensome.
Plugins would also encourage projects such as Mozilla to contribute to 
gcc to implement various backend improvements to make various plugins 
possible. I think GCC could gain some "accidental" contributors this way.
i believe that this would also have an additional effect of making GCC 
the strongly suggested compiler for development as it would be able to 
provide development benefits not (yet?) available in most compilers.
>
> LD_PRELOAD would work just as well as having gcc directly support
> plugins, provided that certain internal things are never made
> file-local.  Someone could write a helper library to make it
> relatively simple to hook in.  But... I looked at this recently, and
> since gcc is not linked with -rdynamic, it is a non-starter.
>   
Tom, I don't know much about linkers and LD_PRELOAD. Would making 
LD_PRELOAD work be easier than making an unstable plugin API?

Taras