[M3devel] main in C or not?

[Tony Hosking]

Antony Hosking | Associate Professor | Computer Science | Purdue University
305 N. University Street | West Lafayette | IN 47907 | USA
Office +1 765 494 6001 | Mobile +1 765 427 5484




On 23 Aug 2010, at 17:51, Jay K wrote:

> Hm. Interesting subtle angle you point out.
> I have seen very few systems with ld but not cc. e.g. OLPC default install.
> My HP-UX/hppa machine came with only a K&R cc.
> Irix might have come with no official cc, but hunting around I found one that worked well enough to build gcc.
> AIX maybe also.
> We could potentially call ld directly.
>   But in general I don't write the configuration files that way, they run cc for linking.
> *.c is used a bunch in m3core but not much else.
> 
> 
> On the other hand:
>   cc is fairly ubiquitous.
>   We have a "plan" for a "new distribution format" that will require cc -- users will build more of the
>    system. Though we'll still provide binaries for some systems.
> 
> 
> I'm *really* interested in a C-generating backend, which will subsume this.

How will source-level debugging work in this instance?

> Except perhaps systems like NT386, and maybe we'll expand that set.
> I'm becoming increasingly frustrated with the gcc backend.
> 
> 
> I can compromise and leave the code in m3linker, but I still like the change in cm3 where the configuration
> is ignored.
> 
> 
> I'll still go ahead and make the C code typesafe via ANSI prototypes.
>   (potentially breaking HP-UX/hppa, but when I get back to that system I'll probably #ifdef
> all the breakage, or require an ANSI compiler such as gcc; I assume nobody really
> cares about K&R).
> 
> 
>  Generating main in C seems to help some platforms, e.g. SOLgnu, SOLsun, SPARC32_LINUX,
> but I admit I didn't fully debug these. And then, removing variations among configurations, I like.
> But that can be achieved via the small change for now and leaving the support in.
> 
> 
>  - Jay
> 
> > Date: Mon, 23 Aug 2010 13:57:01 +0200
> > From: wagner at elegosoft.com
> > To: m3devel at elegosoft.com
> > Subject: Re: [M3devel] main in C or not?
> > 
> > Quoting Jay K <jay.krell at cornell.edu>:
> > 
> > > There has long been a configuration variable: MAIN_IN_C.
> > >
> > > I propose that main always be in C. I made that so already, a small change.
> > >
> > > I further propose that the support for main to not be in C be removed.
> > >
> > > "Not in C" is "generating it via the backend", directly an .obj for NT386, or
> > > going through the gcc backend for Posix.
> > >
> > > Furthermore, I'll cleanup the C to be more typesafe by using ANSI C.
> > >
> > > I have this change about ready.
> > >
> > > I don't think avoiding C is valuable and I'd rather have fewer 
> > > configuration variables.
> > > Pick one approach that works reasonably always.
> > 
> > This requires that every user must have a C compiler in addition to
> > cm3. I thought the default was not to generate C, and just require
> > a C compiler for special runtime support.
> > 
> > I'm not sure if this really a valid argument for the systems we support
> > though, as we also need a system linker, and that is probably bundled with
> > the C compiler in a development package.
> > 
> > Olaf
> > -- 
> > Olaf Wagner -- elego Software Solutions GmbH
> > Gustav-Meyer-Allee 25 / Gebäude 12, 13355 Berlin, Germany
> > phone: +49 30 23 45 86 96 mobile: +49 177 2345 869 fax: +49 30 23 45 86 95
> > http://www.elegosoft.com | Geschäftsführer: Olaf Wagner | Sitz: Berlin
> > Handelregister: Amtsgericht Charlottenburg HRB 77719 | USt-IdNr: DE163214194
> > 

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