RFR(xxs): 8172579: 8168503 broke AIX build

[Magnus Ihse Bursie]

On 2017-01-12 09:56, Thomas Stüfe wrote:
> Hi Volker,
>
> thanks for the hint. GNU grep works, so I close this as wontfix.
You might want to add a test in configure that it is picking up a 
correct grep.

/Magnus

>
> ..Thomas
>
> On Wed, Jan 11, 2017 at 6:51 PM, Volker Simonis <volker.simonis at gmail.com>
> wrote:
>
>> Hi Thomas,
>>
>> why not simply using GNU grep? We already insist for so many other tools
>> on the GNU version that this wouldn't be a big thing.
>>
>> And as far as I remember, GNU grep is already installed on most of our
>> machines anyway. You just have to place /opt/freeware/bin in front of your
>> PATH.
>>
>> Your fix is actually also fine, although it breaks the informal code
>> formatting rules, which require the indentation of wrapped strings. But it
>> is also quite sensitive and I'm sure this will break again in the future
>> (in this or in other places).
>>
>> By the way, why does it break for 'cds' if it didn't for 'jvmci'? I didn't
>> knew that we support 'cds' on AIX either?
>>
>> Regards,
>> Volker
>>
>> Thomas Stüfe <thomas.stuefe at gmail.com> schrieb am Mi., 11. Jan. 2017 um
>> 16:09:
>>
>>> Dear all,
>>>
>>>
>>>
>>> please take a look at this tiny fix:
>>>
>>>
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8172579
>>>
>>> Webrev:
>>>
>>> http://cr.openjdk.java.net/~stuefe/webrevs/8172579-colon-
>>> 8168503-broke-AIX-build/webrev/common/autoconf/hotspot.m4.udiff.html
>>>
>>>
>>>
>>> JDK-8168503 exposed a bug in AIX grep. AIX grep, when called like this:
>>>
>>> "grep -Fx <patternlist>" is unable to handle empty patterns correctly.
>>>
>>> 8168503 added a line break in the definition of a variable:
>>>
>>>
>>>
>>>   VALID_JVM_FEATURES="compiler1 compiler2 zero shark minimal dtrace jvmti
>>>
>>> jvmci \
>>>
>>> -    graal fprof vm-structs jni-check services management all-gcs nmt cds
>>>
>>> static-build aot"
>>>
>>> +    graal fprof vm-structs jni-check services management all-gcs nmt cds
>>> \
>>>
>>>
>>>
>>> +    static-build link-time-opt aot"
>>>
>>>
>>>
>>>
>>>
>>> So now, "cds" is followed by multiple spaces, which are later expanded to
>>>
>>> multiple newlines, and grep is unable to match the pattern immediately
>>>
>>> preceding these newlines (in this case, "cds"). This causes the
>>>
>>> HOTSPOT_VALIDATE_JVM_FEATURES
>>>
>>> function to fail with "Invalid JVM feature: cds".
>>>
>>>
>>>
>>> The error would also happened before when trying to match "jvmci", but so
>>>
>>> far we do not build jvmci on powerpc.
>>>
>>>
>>>
>>> The workaround for now is just to remove the superfluous spaces.
>>>
>>>
>>>
>>> I tried for some hours to find a better solution but could not find one
>>>
>>> which was small enough and worked on all platforms.
>>>
>>>
>>>
>>> I tried using sed to change multiple spaces to a single space, but did not
>>>
>>> get it to work correctly on AIX either.
>>>
>>>
>>>
>>> I thought about passing the pattern list as file to grep - which opposed
>>> to
>>>
>>> passing the pattern in the command line works as expected - but refrained
>>>
>>> from this because creating temporary files is error prone.
>>>
>>>
>>>
>>> I attempted to change the whole NEEDLE/STACK expression to a loop checking
>>>
>>> each single feature with '=~' against the list of valid features, but this
>>>
>>> felt too intrusive.
>>>
>>>
>>>
>>> The proposed fix is not the most elegant one but the risk for other
>>>
>>> platforms is minimal and it works.
>>>
>>>
>>>
>>> Kind Regards, Thomas
>>>
>>>