RFR [jcov, unfilled]: jcov does not instrument files with NestHost/NestMembers attributes

Leonid Kuskov Leonid.Kuskov at Oracle.com
Tue Aug 7 17:42:26 UTC 2018

Hi Jan,

These fixes look good. We already use the same approach in private jcov 
build for instrumenting JDK 12.
Please apply the patch further I will add couple cosmetic fixes that I 
have for JDK 12 classfiles.


On 8/7/18 08:37, Jonathan Gibbons wrote:
> Ooops, wrong list (asmtools-dev)
> cc: jcov-dev
> -- Jon
> On 8/7/18 8:25 AM, Jan Lahoda wrote:
>> Hi,
>> It seems that jcov cannot instrument files with NestHost/NestMembers 
>> attributes (JDK 11 classfiles), and silently uses the original 
>> version. The reason appears to be that even though it uses ASM 6.2, 
>> which knows about those attributes, the visitors are using "ASM6" 
>> compatibility flag, which does not support these attributes.
>> My proposal here is to upgrade the compatibility flag to 
>> "ASM7_EXPERIMENTAL" compatibility level. It might be better to define 
>> a constant for the compatibility level constant, so that on next 
>> upgrade, we don't need to modify so many files. The proposed patch is 
>> here:
>> http://cr.openjdk.java.net/~jlahoda/jcov-nesthost/webrev.allow.nesthost.00/ 
>> Also, we could enhance the build script to allow running tests:
>> http://cr.openjdk.java.net/~jlahoda/jcov-nesthost/webrev.test.00/
>> If these would seem to go in a reasonable direction, I'll file bugs. 
>> It may be necessary to do a few more changes to support JDK 12 
>> classfiles.
>> Any feedback is welcome!
>> Thanks,
>>     Jan

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