Re: Variables allocated on stack

From	"BartC" <bc@freeuk.com>
Newsgroups	comp.lang.c
Subject	Re: Variables allocated on stack
Date	2011-11-26 23:00 +0000
Organization	A noiseless patient Spider
Message-ID	<jarr5c$vv0$1@dont-email.me> (permalink)
References	(3 earlier) <jant5d$lji$1@speranza.aioe.org> <janutd$50o$1@dont-email.me> <slrnjd12fr.1q65.usenet-nospam@guild.seebs.net> <jaqh9b$ght$1@dont-email.me> <l2u7q8-m8a.ln1@voyager.wichi.de.vu>

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"Markus Wichmann" <nullplan@gmx.net> wrote in message
news:l2u7q8-m8a.ln1@voyager.wichi.de.vu...
> On 26.11.2011 12:07, BartC wrote:
>
>> Surely compiler writers can do what they like - within their own
>> implementation? Calling conventions are only important when calling
>> foreign
>> and OS functions, and being called from outside.
>>
>
> Yeah, that's right!
>
> Only... every function not defined "static" may be called "from the
> outside". Every call to a function only declared (and not qualified
> "static") but not defined may be to a foreign function.

If no special attributes are defined, then it is just the private calling 
convention used by this compiler. Although it might have a few other 
conventions up it's sleeve, for example when creating exported functions 
accessed via dynamic library by other languages, or calling the OS.

I'm used anyway to declaring in my non-C language:

clang function puts (istring)
windows function Sleep(int)

That is, specify the calling conventions used by these imported functions 
(in this case, also imported via DLL files). Although I believe Windows was 
originally written in C, it uses a different call convention from actual C 
programs.

Fortunately the only C functions I've had to import so far all use a 
consistent call convention. So for functions shared across applications, 
this would be a good idea. But should this be defined by the ABI? I 
understood an ABI was mainly for interfacing to the OS; it was not 
necessarily a standard for C language compilers. Or, since other languages 
are available, for *every* implementation of *every* language for that 
platform.

> Plus, when you ask a compiler writer whether he want's to include
> _two_different_ calling conventions in his compiler with the added
> maintenance and stuff, guess what he'll say.

Isn't that what happens anyway, when calling a function in a different
language? (pascal, stdcall and so on.) (And I'm working right now on a 
project with I think 4 different conventions to take care of. It's not that 
big a deal. More difficult is matching and converting datatypes across 
languages.)

> Writing a register
> allocator is hard enough without having to differentiate internal and
> external functions and function calls.

Most code generation should be for functions following the chosen
call-convention of the compiler. This may well have been chosen to be easier
to compile for. Only actual calls to other conventions, or 'callback'
functions, might need some work.

-- 
Bartc

Thread

Variables allocated on stack Bogdan <cristeab@gmail.com> - 2011-11-24 13:28 -0800
  Re: Variables allocated on stack Ian Collins <ian-news@hotmail.com> - 2011-11-25 10:40 +1300
  Re: Variables allocated on stack jacob navia <jacob@spamsink.net> - 2011-11-24 23:30 +0100
    Re: Variables allocated on stack Quentin Pope <qp19433@hotmail.NOSPAM.com> - 2011-12-02 22:33 +0000
      Re: Variables allocated on stack jacob navia <jacob@spamsink.net> - 2011-12-03 00:54 +0100
      Re: Variables allocated on stack Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-12-02 23:33 -0800
        Re: Variables allocated on stack Keith Thompson <kst-u@mib.org> - 2011-12-03 02:25 -0800
  Re: Variables allocated on stack jt@toerring.de (Jens Thoms Toerring) - 2011-11-24 23:37 +0000
  Re: Variables allocated on stack Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-25 01:53 -0800
    Re: Variables allocated on stack "BartC" <bc@freeuk.com> - 2011-11-25 11:05 +0000
      Re: Variables allocated on stack jacob navia <jacob@spamsink.net> - 2011-11-25 12:11 +0100
        Re: Variables allocated on stack "BartC" <bc@freeuk.com> - 2011-11-25 11:40 +0000
          Re: Variables allocated on stack jacob navia <jacob@spamsink.net> - 2011-11-25 12:52 +0100
            Re: Variables allocated on stack Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-27 02:31 -0800
              Re: Variables allocated on stack jacob navia <jacob@spamsink.net> - 2011-11-27 13:28 +0100
              Re: Variables allocated on stack André Gillibert <MetaEntropy.removeThis@gmail.com> - 2011-11-27 13:44 +0100
                Re: Variables allocated on stack jacob navia <jacob@spamsink.net> - 2011-11-27 15:44 +0100
                Re: Variables allocated on stack André Gillibert <MetaEntropy.removeThis@gmail.com> - 2011-11-27 17:34 +0100
                Re: Variables allocated on stack jacob navia <jacob@spamsink.net> - 2011-11-27 18:28 +0100
                Re: Variables allocated on stack Ian Collins <ian-news@hotmail.com> - 2011-11-28 07:48 +1300
                Re: Variables allocated on stack gwowen <gwowen@gmail.com> - 2011-11-29 01:11 -0800
                Re: Variables allocated on stack jacob navia <jacob@spamsink.net> - 2011-11-29 17:02 +0100
          Re: Variables allocated on stack Seebs <usenet-nospam@seebs.net> - 2011-11-26 07:21 +0000
            Re: Variables allocated on stack "BartC" <bc@freeuk.com> - 2011-11-26 11:07 +0000
              Re: Variables allocated on stack Markus Wichmann <nullplan@gmx.net> - 2011-11-26 21:16 +0100
                Re: Variables allocated on stack "BartC" <bc@freeuk.com> - 2011-11-26 23:00 +0000
                Re: Variables allocated on stack Ian Collins <ian-news@hotmail.com> - 2011-11-27 12:12 +1300
                Re: Variables allocated on stack "BartC" <bc@freeuk.com> - 2011-11-26 23:35 +0000
                Re: Variables allocated on stack Ian Collins <ian-news@hotmail.com> - 2011-11-27 12:48 +1300
                Re: Variables allocated on stack Markus Wichmann <nullplan@gmx.net> - 2011-11-27 10:56 +0100
                Re: Variables allocated on stack Keith Thompson <kst-u@mib.org> - 2011-11-28 16:17 -0800
                Re: Variables allocated on stack Markus Wichmann <nullplan@gmx.net> - 2011-11-30 17:04 +0100
                Re: Variables allocated on stack Keith Thompson <kst-u@mib.org> - 2011-11-30 09:36 -0800
                Re: Variables allocated on stack Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-25 05:11 -0800
                Re: Variables allocated on stack Keith Thompson <kst-u@mib.org> - 2012-01-25 12:23 -0800
                Re: Variables allocated on stack Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-31 19:11 -0800
                Re: Variables allocated on stack Ian Collins <ian-news@hotmail.com> - 2011-11-27 13:06 +1300
                Re: Variables allocated on stack André Gillibert <MetaEntropy.removeThis@gmail.com> - 2011-11-27 11:20 +0100
                Re: Variables allocated on stack David Thompson <dave.thompson2@verizon.net> - 2012-01-19 02:43 -0500
              Re: Variables allocated on stack Seebs <usenet-nospam@seebs.net> - 2011-11-28 08:32 +0000
    Re: Variables allocated on stack Bogdan <cristeab@gmail.com> - 2011-11-26 01:18 -0800
      Re: Variables allocated on stack Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-26 08:36 -0500
  Re: Variables allocated on stack Seebs <usenet-nospam@seebs.net> - 2011-11-26 07:21 +0000
  Re: Variables allocated on stack Noob <root@127.0.0.1> - 2011-11-29 11:51 +0100

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