Re: [PATCH GCC]Fix broken Canadian when checking isl library support

["Bin.Cheng" <amker dot cheng at gmail dot com>]

On Thu, Aug 21, 2014 at 5:08 PM, Richard Biener
<richard.guenther@gmail.com> wrote:
> On Thu, Aug 21, 2014 at 10:28 AM, Bin Cheng <bin.cheng@arm.com> wrote:
>> Hi,
>> Canadian build of arm/aarch64 (and other targets) toolchains are broken
>> because of isl library check.  There is below code in top level gcc
>> configuration.
>>
>>     { $as_echo "$as_me:${as_lineno-$LINENO}: checking for version 0.12 of
>> ISL" >&5
>> $as_echo_n "checking for version 0.12 of ISL... " >&6; }
>>     if test "$cross_compiling" = yes; then :
>>   gcc_cv_isl=yes
>> else
>>   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
>>
>> For Canadian build, corss_compiling is set to `yes', then gcc_cv_isl is set
>> to `yes' accordingly, no matter whether isl library is available or not.
>> We also can't set it to `no' by default, because "--with-isl=xxxx" option
>> would be nullified in this way.  I think the best we can do here is add
>> AC_LINK_IFELSE when checking.
>>
>> This patch fixes the issue.
>>
>> Is it OK?
>
> I think it would be better to identify a set of features we rely on that
> are not present in earlier versions and make the test a link
> test unconditionally.
>
> Tobias, are there include files / types / functions we require
> that are not available in earlier versions?
>
> Unfortunately ISL upstream doesn't have ISL version defines in
> version.h (and no, don't go the cloog route of auto-generating
> the version.h file!).  That way we still can't do any sanity check
> of an in-tree version (which we have to check from the source,
> before compiling it).
>
> If you don't want to work on this patch further the present patch is ok.

Hi Richard, thanks for the suggestion.
Meanwhile, I need to get this in firstly since it's a build breakage.
I will put the re-factor on to-do list but can't guarantee that.

Thanks,
bin
>
> Thanks,
> Richard.
>
>> 2014-08-21  Bin Cheng  <bin.cheng@arm.com>
>>
>>         * config/isl.m4 (ISL_CHECK_VERSION): Check link of isl library
>>         for cross_compiling.
>>         * configure: Regenerated.