[GSoC] Elimination of CLooG library installation dependency

[Tobias Grosser]

On 06/08/2014 17:21, Roman Gareev wrote:
> Hi Tobias,
>
> I've attached the patch, which should eliminate CLooG library
> installation dependency from GCC. The CLooG AST generator is still the
> main code generator, but the isl ast generator will be chosen in case
> of nonavailability of CLooG library.

Nice.

> However, I've found out a problem. Almost all the functions of the ISL
> cannot be used without installed CLooG. (I get errors which contain
> “undefined reference to...”). Maybe I missed something. What do you
> think about this?

This is surprising.

What is the exact error message? To which library does gcc link (Check 
with 'ldd cc1')? I wonder if gcc happens to link against the system 
CLooG/isl instead of the ones you installed?
Also, does objdump -x libisl.so show those missing symbols?

> I also have a few questions about gcc. Could you please answer them?
>
> Should Makefile.in be regenerated or manually changed? (I haven't
> found out how to regenerate.)

I think it is manually maintained.

> I've used printf to print “The CLooG code generator cannot be used
> +(CLooG is not available). The ISL code generator was chosen.\n”.
> Should another function be used for this purpose?

I have no idea. Let's leave it for now. I expect the CLooG code to 
disappear very soon.

Also, regarding this patch. It seems you mix two important changes.

1) The configure/makefile changes that make cloog optional
2) The switch from isl to cloog

Best starting with 2), followed by 1).

To commit 2), I would like you to run a wider set of tests (e.g., the 
LLVM test suite). If this passes successful, we should give a headsup on 
the GCC mailing list and ask other people to try the new isl support.
If now bugs have found, we switch.

Cheers,
Tobias