Re: [gobo-eiffel-develop] Problems when installing GEC

[Eric B. <er...@go...>]

Hi Wolfgang,

Wolfgang Jansen wrote:
> I tried to install the new GOBO (5.6) release and ran
> immediately into trouble: my preferred C compiler is "cc"
> but command "$GOBO/install.sh cc" stopped with the message
> 
>   Unknown C compiler: cc
> 
> It is really surprising that the native C compiler of many platforms
> is not supported.

The problem is that I only have access to Windows platform.
So I can only work and test on this platform. At some point
SourceForge made available other platforms through their
compile farm:

    http://en.wikipedia.org/wiki/Compiler_farm

But they don't provide this service anymore ;-( The reason
why only gcc was made available is because that's the only
C compiler that was available on SourceForge's compile farm
platforms as far as I know. But people are free to test gec
on other platforms and with other C compilers and give me
some feedbacks.

    http://www.gobosoft.com/eiffel/gobo/gec/platforms.html

BTW, what platform are you using?

> When trying the same with "gcc" then many warnings like the following
> were issued:
> 
>   gec.c: In function `T202f63':
>   gec.c:82734: warning: cast to pointer from integer of different size
> 
> Line 82734 in C code reads
> 
>   t2 = ((T0*)gevoid(((T202*)(C))->a20, l2));
> 
> whereas "gevoid" is declared as
> 
>   extern int gevoid(T0* C, ...);
> 
> Thus, the bad cast is from "int" to "T0*", i.e. from 4 to 8 bytes
> on a Tru64 platform (as I'm working on). I think, the solution is
> to redefine "gevoid" like "T0* gevoid(T0* C, ...)".
> Just for curiosity, what is "gevoid" good for? Its definition seems
> to indicate that it is the check for void targets, but there is no test
> (neither in the routine nor around its call), merely printing an error
> message and aborting the program. And if aborting in any case has been
> planned, why then a return value?

'gevoid' is the result of the code optimizer. It means that in the
corresponding Eiffel code, no matter what, this call will result in
a call on Void target. For example:

      local
         s: STRING
      do
         s.append_string ("gobo")

'gevoid' is then emitted instead of the call. I think that the problem
above is that I tried to use the same 'gevoid' function to replace all
kinds of calls, be them procedures or functions with expanded or
reference result. I was hoping that explicit type cast would make the
C compiler happy, which it did with the compilers I tried. Apparently
I will have to rethink about it and find a better implementation.

> After the warnings an error message follows:
> 
>   as1: Error: /usr/tmp/cciOAHCE.s, line 5: gp-relative segments together 
> exceed 64k bytes
> 
> Probably, the generated object file is too large.
> (I had the same effect also earlier when bootstrapping the SE compiler
> from a single C file instead from a split one.)

Hmmm, I asked someone to test on Linux (Ubuntu 7.04) with gcc and
everything worked OK. It was not my intention to work on C file
splitting in the near future. I will probably have to reconsider.

> Then many errors of the form
>   /usr/users13/wolfgang/eiffel/gobo/install.sh: 
> /usr/users13/wolfgang/eiffel/gobo/bin/gec: not found
>   /usr/users13/wolfgang/eiffel/gobo/install.sh: geant: not found
> 
> occurred, probably a consequence of the previous error.

Yes.

> PS:
> After adding the "cc" compiler to "install.sh" the outcome was
> as follows:
> 
>   cc: Warning: gec.c, line 479288: Non-void function "gevoid" does not 
> contain a return statement. (missingreturn)
>   int gevoid(T0* C, ...)
> 
> The bad cast is not rejected and the compilation of "gec"
> is successful. Then most of "geant", ... are compiled successfully
> where C compilation is again done by "gcc" (to be seen by
> the warnings concerning bad casts). Why "gcc"?

You will have to configure gec to use cc as C compiler. See
section "Back-end C compiler" in:

    http://www.gobosoft.com/eiffel/gobo/gec/usage.html


What this install script does is just generate the binary files
in $GOBO/bin. For those of you who don't want to have to generate
them by themselves, I made available the binaries for Windows in:

   https://sourceforge.net/project/showfiles.php?group_id=24591

Anyone is welcome to provide the binaries for his platform so
that I can make them available on SourceForge as well.

Wolfgang, thank you for your feedback, and don't hesitate to
send me a cc.cfg file if you manage to make one working on
your platform.

-- 
Eric Bezault
mailto:er...@go...
http://www.gobosoft.com