Re: Phase 1 of gcc-in-cxx now complete

[Richard Guenther <richard dot guenther at gmail dot com>]

On Thu, Jun 25, 2009 at 10:32 PM, Ian Lance Taylor<iant@google.com> wrote:
> I am pleased to report that if you configure gcc with
> --enable-build-with-cxx, which causes the core compiler to be built
> using a C++ compiler, a bootstrap on x86_64-unknown-linux-gnu now
> completes.
>
> I would like to encourage people to try using --enable-build-with-cxx in
> other configuration--other bootstraps, cross-compilers--to see how well
> it works. ?Please let me know if you run into problems that you don't
> know how, or don't have time, to fix.
>
> This completes the first phase of the gcc-in-cxx project, which I
> started about one year ago at the 2008 GCC Summit.
>
> At this point I personally will probably not work on this project for
> some weeks, other than bug fixing. ?Further steps on the overall project
> of converting gcc to C++ are:
>
> * Write a coding standards document for gcc in C++.
>
> * Convert more code to be compiled as C++ when using
> ?--enable-build-with-cxx. ?Currently the generator programs
> ?(genattrtab, etc.) and libcpp are still compiled as C.
>
> * Develop some trial patches which require C++, e.g., convert VEC to
> ?std::vector.
>
> * Test starting the bootstrap with earlier versions of the compiler to
> ?see which C++ compiler version is required, and document that.
>
> * Petition the steering committee for formal approval to switch to C++.
>
> I do not expect to convert the compiler to require C++ in the 4.5
> timeframe.

I think it would be a good thing to try forcing the C++ host compiler
requirement for GCC 4.5 with just building stage1 with C++ and stage2/3
with the stage1 C compiler.  --disable-build-with-cxx would be a
workaround for a missing C++ host compiler.

That should give us an idea on what problems we are going to face
when switching to actual C++ code.

Richard.

> I encourage anybody who is interested to experiment with these further
> steps.
>
> Ian
>