GCC 4.7.0RC: Mangled names in cc1

[Ludovic Courtès]

Hi,

Ian Lance Taylor <iant@google.com> skribis:

> ludovic.courtes@inria.fr (Ludovic Courtès) writes:
>
>> Ian Lance Taylor <iant@google.com> skribis:
>>
>>> ludovic.courtes@inria.fr (Ludovic Courtès) writes:
>>>
>>>> Ian Lance Taylor <iant@google.com> skribis:
>>>>
>>>>> ludovic.courtes@inria.fr (Ludovic Courtès) writes:
>>>>>
>>>>>> However, this means that plug-ins must now be built with g++, except
>>>>>> when GCC was configured with --disable-build-poststage1-with-cxx.  This
>>>>>> seems difficult to deal with, for plug-in writers.
>>>>>
>>>>> This is an unfortunate truth during our transition to building gcc with
>>>>> C++.  There is going to be a period of time when the compiler may be
>>>>> built as either C or C++.  The end goal is for the compiler to always be
>>>>> built with C++, but until we reach that state I think plugin writers
>>>>> will have to test.
>>>>
>>>> What about wrapping the C API in extern "C"?
>>>
>>> We eventually will want the internal APIs to be C++, so this transition
>>> will inevitably happen at some point.
>>
>> I understand the goal.  However, should a C++ API be added, the C-only
>> part could still be kept extern "C".
>
> We are talking here about internal GCC functions.  We are not talking
> about an actual defined API.  The defined API is in plugin-api.h, and
> that remains extern "C".  There is no "C-only part" of the internal API.

Hmm <plugin-api.h> is for linker plug-ins; <gcc-plugin.h> provides
nothing more than the event mechanism.

Symbols declared in <tree.h> are mangled, for instance.  I’m not sure
whether <tree.h> is considered internal or not, but I can hardly see
what kind of plug-in could be written without using it.

>> For 4.7.0, as Duncan Sands writes, it would be a very helpful for the
>> ABI to be independent of configuration options–i.e., either mangled or
>> unmangled symbols.
>
> That just postpones the pain to gcc 4.8.0.

In 4.8 things will be easier: plug-ins will have to be compiled with g++.

In 4.7, finding out whether gcc or g++ should be used is left as an
exercise to the plug-in writer, which is inconvenient at best.

Thanks,
Ludo’.