Re: [PATCH 5/5] add libcc1

[Jeff Law <law@redhat.com>]

On 06/20/14 09:33, Tom Tromey wrote:
>>>>>> "Trevor" == Trevor Saunders <tsaunders@mozilla.com> writes:
>
> Trevor> I'm curious, what is the reason you choose not to write this in C++11 or
> Trevor> later?  Its distributed with gcc, so the only case where you aren't
> Trevor> building with the in tree compiler and libraries is when your cross
> Trevor> compiling gcc, and it doesn't seem particularly important to support
> Trevor> building the plugin or library in that configuration.  So istm you could
> Trevor> go all the way and assume you are being built with trunk gcc and
> Trevor> libraries.
>
> The plugin has to be ABI compatible with GCC itself, and my
> understanding was that C++11 and "however GCC is built" are not
> necessarily compatible.
Presumably you're referring to the upcoming abi breakage for C++ pair & 
list.

There's ways around that with the ABI tagging we're using, but at least 
for now, the safe thing to do for something that must be ABI compatibile 
with GCC itself is to stick with C++03 mode.

>
> Switching to C++11 would be an improvement -- variadic templates would
> simplify the RPC code (with a complicated caveat).  So if it is possible
> I am interested.
There'll probably be a day when we can bless C++11 for building GCC 
itself and any associated plugins, but we're not at that point right now.

> Trevor> So can we add C++ stuff to libiberty and allow building
> Trevor> libiberty without it for binutils / gdb, or can we do something
> Trevor> else to avoid this kind of stuff?
>
> One way would be to just make a new top-level directory for a new
> library.
Seems like the easiest solution, at least for now.

>
> Thanks.  I changed it to do a NULL check.  It's nothrow because nothing
> in libcc1 or gdb is prepared for a C++ exception.  While I like
> exceptions (gdb uses its own longjmp-based exception system
> extensively), my understanding is that they aren't currently used in
> gcc.
Right.  Or if we're using them in GCC, any such use is well buried in 
non-critical , not widely known & marginally, if at all, tested code.

Jeff