testsuite, failures galore

[Simon Marlow]

On 31/05/2011 13:24, Daniel Fischer wrote:
> On Tuesday 31 May 2011 12:31:36, Simon Marlow wrote:
>>> The ticket has low priority, but if anybody has an idea how to check
>>> whether libbfd depends on libz in the configure script, I'd appreciate
>>> it.
>>
>> Could you install a shared version of libbfd?
>
> I have one,
>
> $ locate libbfd
> /home/dafis/.deps/libbfd.Plo
> /usr/lib/libbfd-2.20.0.20100122-6.so
> /usr/lib/libbfd.a
> /usr/lib/libbfd.la
>
> The problem is, as far as I can tell, that a) libbfd.a is picked up instead
> of the .so in the first place, and b) that both depend on libz:
>
> $ ldd /usr/lib/libbfd-2.20.0.20100122-6.so
>          linux-gate.so.1 =>   (0xffffe000)
>          libz.so.1 =>  /lib/libz.so.1 (0xb743e000)
>          libc.so.6 =>  /lib/libc.so.6 (0xb72d3000)
>          /lib/ld-linux.so.2 (0xb76fd000)

What you need is libbfd.so, which is a symbolic link to the versioned 
library (libbfd-2.20.0.20100122-6.so).  This is normally installed by 
the development version of the library (e.g. libbfd-dev on 
Debian-derived distros).

The shared version has the dependency built-in, so the GHC build system 
wouldn't have to do anything (that's how it works here).

> I'm far from an expert, but as far as I can see, there is already such a
> test, in configure.ac:
>
> AC_CHECK_LIB(bfd,    bfd_init)

I think that only tests for the presence of the symbol in the library, 
it doesn't test that compiling an executable against that library 
actually works.

> with a test using bfd_init in configure. Unfortunately, that doesn't detect
> if libz is needed without using some functions depending on it.
> If I had the slightest idea how to make it detect the dependency on libz, I
> happily would, but I've not yet found any introduction to shell scripting
> or using autotools accessible to a complete beginner.

Yes, I'm afraid the learning curve is a bit steep.  It's so hard to get 
right that I wouldn't even attempt to try to fix it without a machine to 
test on!  A good place to start would be tests that do similar things - 
a quick look at the code suggests AC_COMPILE_IFFELSE and AC_LINK_IFFELSE 
might be useful, also FP_CHECK_FUNC looks like it might do what you want.

Cheers,
	Simon