Re: PATCH RFA: Build stages 2 and 3 with C++

[Ian Lance Taylor <iant@google.com>]

Romain Geissler <romain.geissler@gmail.com> writes:

> This new build behavior broke former plugins built with gcc. Indeed,
> all cc1 function symbols are now mangled and thus with the current
> trunk, plugins should also look for mangled symbols (and so built
> with g++).
>
> What's the new GCC policy about that ? Do plugins have to be built
> using g++ only, or does the plugin developer have the choice to
> use both gcc and g++ according to it's need (at the cost of adding
> extern "C" {…} in almost every headers to forbid mangling) ?

I think that ideally we would have a well-defined plugin interface,
plugins would stick to calling that, and that interface would be a C
interface.  (I see that gcc-plugin.h does already provide a C interface
even when gcc is compiled with C++.)

However, since we currently permit plugins to call anything in gcc, I
think the answer is going to have to be that plugins which do that
should be compiled with C++.  I don't think that adding extern "C" to
all gcc header files is the right approach.  Adding extern "C" to a few
selected header files seems fine.

Ian