Building GCC using C++

[Richard Biener]

On Tue, Jan 15, 2013 at 6:46 AM, Uday P. Khedker <uday@cse.iitb.ac.in> wrote:
> I was trying to understand the exact meaning of a loose statement
> floating around ("gcc has moved to C++ from version 4.7 onwards).
>
> I reckon from http://gcc.gnu.org/wiki/gcc-in-cxx that now gcc is
> compiled using C++. However, the very first line of the description
> confused me. It says:
>
>> GCC has been building stages 2 and 3 in C++ mode for a while.
>
>
> My understanding was that stage 2 is built using the compiler created
> in stage 1 and stage 3 is built using the compiler created in stage 2.
> (Please see slide 17/53 in
> http://www.cse.iitb.ac.in/grc/gcc-workshop-12/downloads/slides/gccw12-config-build.pdf).
>
> Can someone tell me what is the meaning of building stage 2 in C++
> mode? If I restrict my languages (using --enable-languages) to C,
> how can stage 2 be built in C++ mode? Or is it that regardless of
> the choice given using --enable-languages option, internally C and
> C++ compiler are created anyway? The build logs do not seem to bear
> out the above statement.

The C++ compiler is created anyway since 4.7 and is used to build
stage2+.  Starting with GCC 4.8 stage1 requires a C++ host compiler.

Richard.

> Thanks and regards,
>
> Uday.
> --
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> Dr. Uday Khedker
> Professor
> Department of Computer Science & Engg.
> IIT Bombay, Powai, Mumbai 400 076, India.
> Email   :       uday@cse.iitb.ac.in
> Homepage:       http://www.cse.iitb.ac.in/~uday
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>
>