Re: porting gcc

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

Aurélien Buhrig <Aurelien.Buhrig@tiempo-ic.com> writes:

> We are designing a 16-bit asynchronous microcontroller. I’ve already ported
> bfd, binutils (including sid simulator) using cgen, and part of gdb (for asm
> debug only) and we are now investigating the best way to have C compiler.
> So my questions are:
>
> 1- How much time do you think it will take to port gcc for this platform
> with a quite simple instruction set, with a good porting guide?

My answer the last time I answered this question:

http://gcc.gnu.org/ml/gcc-help/2008-04/msg00117.html


> 2- What about optimizations? I suppose most of them are platform-independent
> and performed at RTL level, aren't they? But, generally speaking, are there
> many platform-dependent optimizations (I would have to do)? And is it
> possible or how is it complex to have a level of optimization (code
> compactness...) as good as commercial compiler ones (such as IAR, Keil,
> ACE...)?

Most optimizations are platform independent.  The hardest platform
specific one to implement is scheduling; you will have to write a
description of your pipeline.  Some peepholes may be appropriate.
Other than that, you will only need platform specific code if your
processor is unusual in some respect.  Unfortunately, my experience is
that every processor has some unusual aspects.

gcc is a commercial compiler.  If you mean: how does gcc compare to a
proprietary compiler, the answer is that it is very competitive for
conventional processors.


> 3- Finally, some companies may port gcc for us (perhaps in this mailing
> list?). An idea of how much it could be?

I have no idea what the rates are these days, sorry.  In any case the
precise details of your processor make a big difference to the price.

Ian