Re: [Mesa3d-dev] libtool (was CVS and SSE)

[Sven M. H. <pe...@gm...>]

On Tue, May 22, 2001 at 01:12:39PM +0200, Marcelo E. Magallon wrote:
> >> "Sven M. Hallberg" <pe...@gm...> writes:
> 
>  > Then, if we don't know the correct filename (except in special cases
>  > where there is something like an ABI) we can let libtool decide.
>  > After all it's its job! If we stumble across a system with an ABI we
>  > might be violating, we can still incorporate a special-case
>  > treatment.
> 
>  Yes.  My guess is that each (Unix-like) vendor has (an|their own) ABI
>  for OpenGL.  Linux just happens to have one that's used by more than
>  one group.  A quick look arround here indicates that HP-UX's libGL is
>  called libGL.2, IRIX's seems to be called libGL.so with a "MIPS
>  version" of "sgi1.0" (I have never understood SGI's policy regarding
>  SONAMEs, but I've never seen it break, so I guess it's ok).  The other
>  Unix flavors I have access to don't have the vendor's libGL installed
>  on them. 

OK. So we let libtool do its work and (constructively) interfere with it only
where the necessity pops up, right?


>  > Here's the pseudo-code for the install-hook, do you think this would
>  > be OK to do on systems identified as Linux?
> 
>  Hmmm...  the whole ABI bussiness is about the soname *in* the library
>  file.  libtool happyly ignores any -Wl,-soname,libfoo.so.1 you pass to
>  it (because it's not portable).

Oh, I'll try it, too.


>  >         if test `find .libs/ -name libGL.so.1 | grep -c libGL.so.1` != 1; then
>  if there's exactly one file named libGL.so.1 ...
If there's not exactly one.
>  >           libfile=`find .libs/* -not -type l -not -name '*.lai'`
>  look for the library files ... (note there are likely two of these, one
>  libGL.so.x.y.z and one libGL.a -- you *want* the libGL.a, too)
Oh, right. Maybe we should just scrap this whole thing, assuming libtool does
it right.
>  >           if test 'echo $libfile | grep -c $libfile` = 1; then
>  I got lost here.  If there's exactly one shared library?
Oh, this is of course bull. echo $libfile | grep -c '*' = 1 would be correct.
Basically meant as a line count (Is wc -l portable?).
>  >             ln -s @libdir@/$libfile @libdir@/libGL.so.1
>  link libGL.so.1 to this
>  >           else
>  else there's a problem.


>  Like I said, what's important is the SONAME contained in the library,
>  what this file is called is not important.  Like this:

Really?? I thought it was like this:
 SONAME of library X = Y.
 compile executable Z with -lX
  -> linker puts SONAME(X)=Y to NEEDED(Z)
 execute Z
  -> linker looks up library of _name_ Y.
     If lib Y doesn't exist, linker fails.

Is it different?


>  soname=`readelf -d $libfile | sed -ne '/SONAME/ s/.*\[\(.*\)\]/\1/p'`
>  if test $soname != libGL.so.1
>      echo There's a problem ...
>      exit 1
>  else
>      # Asuming libfile is something like libGL.so.1.2.350 (and not
>      # /some/dir/.libs/libGL.so.1.2.350)
>      ln -s $libfile @libdir@/libGL.so.1
>  fi
> 
>  (objdump and readelf are both part of binutils, so on Linux it's safe
>  to asume they are present.  I just happen to like readelf better)

OK.


>  > So you mean, we should include the library depedencies in our library
>  > objects?
> 
>  If possible, yes.  It makes life much simpler.  :-)

Hm. look at this:
--- 8< ---
pesco@crest:~/cvswork/Mesa/src/.libs$ ldd libGL.so
        libvga.so.1 => /usr/lib/libvga.so.1 (0x401de000)
        libSM.so.6 => /usr/X11R6/lib/libSM.so.6 (0x40235000)
        libICE.so.6 => /usr/X11R6/lib/libICE.so.6 (0x4023e000)
        libXmu.so.6 => /usr/X11R6/lib/libXmu.so.6 (0x40254000)
        libXext.so.6 => /usr/X11R6/lib/libXext.so.6 (0x40269000)
        libXi.so.6 => /usr/X11R6/lib/libXi.so.6 (0x40278000)
        libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x40280000)
        libpthread.so.0 => /lib/libpthread.so.0 (0x4035b000)
        libc.so.6 => /lib/libc.so.6 (0x40371000)
        libm.so.6 => /lib/libm.so.6 (0x40483000)
        libXt.so.6 => /usr/X11R6/lib/libXt.so.6 (0x404a5000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x2aaaa000)
pesco@crest:~/cvswork/Mesa/si-glu/.libs$ ldd libGLU.so
        libc.so.6 => /lib/libc.so.6 (0x400b5000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x2aaaa000)
--- >8 ---

libGL already gets these dependencies from the various convenience libs.
Can anyone see whether there are any missing? Since I built the si-glu
Makefile.am's I'll just add -lGL there, right?


>  BTW, I tried -version-info 3:350:2 on IRIX...  not good... the linker
>  exits with a bus error.  Gotta love the MIPSpro tool chain...

Ugh. Do you have any indication why that fails? Maybe it doesn't like the high
REVISION number?


Greetings,
Sven

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