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

Jonathan Gibbons jonathan.gibbons at oracle.com
Tue Aug 7 15:35:31 UTC 2018

cc: asmtools-dev

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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