RFR(xxs): 8172579: 8168503 broke AIX build

[Thomas Stüfe]

Hi Volker,

thanks for the hint. GNU grep works, so I close this as wontfix.

..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
>>
>>