Re: Progress on GCC plugins ?

[Basile STARYNKEVITCH <basile at starynkevitch dot net>]

Tom Tromey wrote:
> > > > > > "Taras" == Taras Glek <taras.judge@shaw.ca> writes:
>
> Tom> LD_PRELOAD would work just as well as having gcc directly support
> Tom> plugins, provided that certain internal things are never made
> Tom> file-local.  Someone could write a helper library to make it
> Tom> relatively simple to hook in.  But... I looked at this recently, and
> Tom> since gcc is not linked with -rdynamic, it is a non-starter.
>
> Taras> Tom, I don't know much about linkers and LD_PRELOAD. Would making
> Taras> LD_PRELOAD work be easier than making an unstable plugin API?
>
> Not really.
>
> The difference would be that with LD_PRELOAD the gcc change would be
> very small -- just linking with -rdynamic.  Maybe you could lobby a
> Linux distro for this :-)


I'm not fully convinced that just LD_PRELOAD is enough to add poor man's 
plugin into GCC.

Plugins into GCC are expected to add optimisation passes (see file 
gcc/passes.c function init_optimization_passes and I don't understand 
what exactly LD_PRELOAD trick (unless you also redefine this very 
function init_optimization_passes in your ld_preload-ed plugin) would 
enable this.

So Tom or Taras, could you please elaborate on this? What tricks are you 
thinking of?

However, you are right in the sense that implementing naive plugins is 
technically easy; apparently the issue is political, not technical (i.e. 
let RMS accept or bless it).

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