[13] RFR (S): 8217404: --with-jvm-features doesn't work when multiple features are explicitly disabled

[Vladimir Ivanov]

Thanks, Igor.

> overall your fix looks reasonable, but w/ it we can get unintentionally disabled features (b/c grep doesn't do full word match). although this problem wasn't really introduced by your fix, I think it's be better to fix it as a part of your patch. I see two possible solutions:

I was aware of such drawback, but decided to leave it as is, since it 
doesn't affect existing features.

>   -  add "-w" to grep, but I am not sure if "-w" is supported by all grep implementations
>   - use $XARGS instead of $ECHO when we get DISABLE_X. in this case you will need to revert your changes in 'if test ...' lines

I'm in favor of using "-w" and I see different grep flags being used 
already, but would like somebody from Build team confirm they are OK 
with such solution.

Best regards,
Vladimir Ivanov

>> On Jan 18, 2019, at 3:33 PM, Vladimir Ivanov <vladimir.x.ivanov at oracle.com> wrote:
>>
>> http://cr.openjdk.java.net/~vlivanov/8217404/webrev.00/
>> https://bugs.openjdk.java.net/browse/JDK-8217404
>>
>> --with-jvm-features doesn't work properly when multiple features are explicitly disabled:
>>
>> $ bash configure --with-jvm-features="-aot -jvmci -graal"
>> ...
>> checking if jvmci module jdk.internal.vm.ci should be built... yes
>> checking if graal module jdk.internal.vm.compiler should be built... yes
>> checking if aot should be enabled... yes
>> ...
>>
>> The problem in the following code:
>>
>>   DISABLE_AOT=`$ECHO $DISABLED_JVM_FEATURES | $GREP aot`
>>   if test "x$DISABLE_AOT" = "xaot"; then
>>     ENABLE_AOT="false"
>>   fi
>>
>> Since DISABLED_JVM_FEATURES ("aot jvmci graal") contains the list of explicitly disabled features, grep over it returns the whole list when there's a match. The subsequent check fails because there's no exact match, though DISABLE_AOT contains "aot" .
>>
>> Proposed fix is to check there's no match instead.
>>
>> After the fix it works as expected:
>>
>> $ bash configure --with-jvm-features="-aot -jvmci -graal"
>> ...
>> checking if jvmci module jdk.internal.vm.ci should be built... no, forced
>> checking if graal module jdk.internal.vm.compiler should be built... no, forced
>> checking if aot should be enabled... no, forced
>> ...
>>
>> (The fix doesn't address the case when one feature has a name which is a proper substring of another feature, but there are no such cases at the moment.)
>>
>> Best regards,
>> Vladimir Ivanov
>