[rfc] Avoid failure when compiler is wrapped.

[Jiri Vanek]

On 01/27/2016 11:09 AM, Magnus Ihse Bursie wrote:
> On 2016-01-25 21:38, Andrew Hughes wrote:
>> ----- Original Message -----
>>> Hello!
>>>
>>> When compiler is wrapped, the configure phase of build fails:
>>>
>>> [...]
>>> checking for gcc... /usr/lib64/cscppc/gcc
>>> configure: Resolving CC (as /usr/lib64/cscppc/gcc) failed, using
>>> /usr/lib64/cscppc/gcc directly.
>>> checking resolved symbolic links for CC... /usr/bin/cscppc
>>> checking if CC is disguised ccache... no, keeping CC
>>> configure: The C compiler (located as /usr/bin/cscppc) does not seem to be
>>> the required GCC compiler.
>>> configure: The result from running with --version was: "Usage:"
>>> configure: error: GCC compiler is required. Try setting --with-tools-dir.
>>> configure exiting with result code 1
>>>
>>>
>>>   From time to time I'm building RPMS for fedora  with wrapped compiler to be
>>>   able to investigate C
>>> code changes. Added is patch, which is allowing to walk around the issue.
>>>
>>> I'm wondering if this is still desired behaviour. or if it can be better
>>> iff-ed out to be by default
>>> on, but eg only disablef on AIX.
>>>
>>> CCed is Andrew, who is facing similar issue on Gentoo.
>>>
>>>
>>>     Thanx!
>>>     J.
>>>
>> The Gentoo issue was different; it's related to distcc failing the version
>> test, rather than symlink issues.
>>
>> I think this block should be removed, not just comment out, if not needed.
>> But first, I think we need to know why the dereferencing is there.
>> Can someone at Oracle shed some light on this?
>
> Maybe a glow of twilight. :) This check was added quite early in the new build system and was
> included in the original integration of the new build system into mainline. I remember vaguely that
> we had issues with some machines with strange setups which turned out to have unexpected symlinks.
> So we thought it was better to clearly show in the configure log which compiler *really* was used.
>
>  From the hg history, I also see that about a year ago, I added this comment in JDK-8034788:
>   # FIXME: This test should not be needed anymore; we don't do that for any platform.
>
> So maybe we should live up to that fixme, and remove the check. :-)
>
> I just realized that we can still keep ability to debug broken systems by resolving the symlink, but
> just printing the result and not modifying the path to the CC we will use. I opened
> https://bugs.openjdk.java.net/browse/JDK-8148351 for this.
>
Thank you for this Magnus.  I will try to prepare regualr webrev based on your suggestion. If you 
fix it in meantime, just let us know :)


Thanx!

   J