Re: Egcs 1.0.3 & Linux

Khimenko Victor (khim@sch57.msk.ru)
Sun, 17 May 1998 21:56:07 +0400 (MSD)


17-May-98 00:17 you wrote:
>
> Just curious to know if Egcs 1.0.3 (released today @
> http://egcs.cygnus.com/egcs-1.0.3.html) correctly compiles the Linux kernel.
> I'm not talking about "yes, I built it and it seems to run just fine after
> one hour". I want to know if it correctly generates code which will run the
> kernel correctly in all instances.
>
You could say that you know ANY COMPILER and any REAL PROGRAM with > 30Mb of
source code with hundreds #ifdef's (like kernel code is) for which you could
say that this compiler will generate correnct code in all instances ? You are
computer god in this case -- I am pretty sure that this task is to much for
human brain...

> I've also been wondering if the problems with Egcs & GCC 2.8.x compiling the
> Linux kernel are bad kernel code or bad compiler code. It would seem to me
> that if it was a compiler problem, then it would be listed in the cavaets or
> bugs listings somewhere, but it isn't.
>
In all known cases this is not compiler problems. There are a lot of subtle
errors (if you have <expression1>+<expression2> code then compiler could
calculate expression1 first and expression2 last or expression2 first and
expression1 last; this is only one simple example). Of course if there will
be found problems in compiler than this errors will be sended to gcc/egcs team...

> GCC 2.8.x has been out for some time, so has Egcs, it's strange that no one
> has fixed the problems that plague compilation of Linux kernel.. probably
> one of the most recompiled things on the planet.
>
There are was found (and fixed) many problems not shown by gcc 2.7.2.3 but
shown by gcc 2.8.x, egcs 1.0.x or pgcc 1.0.x. Unfortunatelly it's almost
impossible to catch all such errors in so big program with so big number of
#ifdef's ...

P.S. All talks above is ONLY about 2.1.10x. 2.0.3x is not designed to be
compiled with anything except gcc 2.7.2.3 and there are no plans to clean them...

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