RFR (XS) 8205702: assert(UseCompressedClassPointers) failed in universe.hpp

[coleen.phillimore at oracle.com]

Hi Calvin, thank you for reporting the bug and the code review and test 
code.

On 6/26/18 5:42 PM, Calvin Cheung wrote:
> Hi Coleen,
>
> The code changes look good.
>
> Since there's a new error message, I'd suggest adding a test to 
> runtime/SharedArchiveFile/SharedArchiveFile.java as follows:
>
> diff --git 
> a/test/hotspot/jtreg/runtime/SharedArchiveFile/SharedArchiveFile.java 
> b/test/hotspot/jtreg/runtime/SharedArchiveFile/SharedArchiveFile.java
> --- a/test/hotspot/jtreg/runtime/SharedArchiveFile/SharedArchiveFile.java
> +++ b/test/hotspot/jtreg/runtime/SharedArchiveFile/SharedArchiveFile.java
> @@ -52,5 +52,13 @@
>                                "-Xshare:on", "-version");
>          out = CDSTestUtils.executeAndLog(pb, "SharedArchiveFile");
>          CDSTestUtils.checkExec(out);
> +
> +        // CDS dumping doesn't work with ZGC
> +        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(true,
> + "-XX:SharedArchiveFile=./SharedArchiveFile.jsa",
> +                                "-XX:+UseZGC",
> +                                "-Xshare:dump");
> +        out = CDSTestUtils.executeAndLog(pb, "SharedArchiveFile");
> +        CDSTestUtils.checkExecExpectError(out, 1, "DumpSharedSpaces 
> (-Xshare:dump) is not supported with ZGC.");
>      }
>  }
>
> (I haven't tested the above)

It needed an -XX:+UnlockExperimentalVMOptions as well, and not reclare pb.

open webrev at http://cr.openjdk.java.net/~coleenp/8205702.02/webrev

>
> Also, I think the new error message should be included in the release 
> notes.
>

I added the test case and it passes.  I don't think having a release 
note for something that nobody would ever do for an experimental option 
is worth having.   But I can look into the ZGC release notes and see if 
there's something that says CDS is not supported.

Thanks,
Coleen
> thanks,
> Calvin
>
> On 6/26/18, 2:13 PM, coleen.phillimore at oracle.com wrote:
>> Summary: Disable CDS with ZGC
>>
>> Tested with:
>> java -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xshare:dump
>> java -XX:+UnlockExperimentalOptions -XX:+UseZGC -Xshare:on -version
>>
>> open webrev at http://cr.openjdk.java.net/~coleenp/8205702.01/webrev
>> bug link https://bugs.openjdk.java.net/browse/JDK-8205702
>>
>> Thanks,
>> Coleen