[9] RFR (M) 8054386: Allow Java debugging when CDS is enabled

Chris Plummer chris.plummer at oracle.com
Tue Jun 2 07:36:29 UTC 2015

[Adding core-libs-dev at openjdk.java.net since this update includes 
changes to jdk/test library code]

Please review the updated webrev:

Webrev: http://cr.openjdk.java.net/~cjplummer/8054386/webrev.02/
Bug: https://bugs.openjdk.java.net/browse/JDK-8054386

There were concerns about the new hotspot tests referencing jdk tests. 
One concern was that if the jdk tests change, they could break the 
hotspot tests, and this might initially go undetected. The other concern 
is that if the jdk and hotspot tests are placed in separate test 
bundles, then it would not be possible to run the hotspot tests.

Because of these concerns, I moved the tests that were in 
hotspot/test/runtime/CDSJDITests to instead be in 
jdk/test/com/sun/jdi/CDSJDITests. There was a slight renaming of the 
tests in the process. Also, I had to update the jdk version of 
ProcessTool.java to include the createJavaProcessBuilder() variant that 
is in the hotspot version of ProcessTool.java.

Lastly, in CDSJITTest.java I changed:

     OutputAnalyzer output = new OutputAnalyzer(pb.start());

to instead be:

     OutputAnalyzer output = ProcessTools.executeProcess(pb);

I had to do this since the jdk version of the OutputAnalyzer constructor 
is not public. The 1st version is what is commonly used in hostspot 
tests, and the 2nd version is what is commonly used in jdk tests. I 
decided to adopt the jdk way rather than make the OutputAnalyzer 
constructors public, although this will probably happen eventually when 
the two versions are unified.



On 5/19/15 7:25 AM, Chris Plummer wrote:
> Hi,
> Please review the following changes for allowing java debugging when 
> CDS is enabled.
> Webrev:http://cr.openjdk.java.net/~cjplummer/8054386/webrev.01/
> Bug:https://bugs.openjdk.java.net/browse/JDK-8054386
> The VM changes are simple. I removed the check that prevents debugging 
> with CDS enabled, and added logic that will map the CDS archive RW 
> when debugging is enabled.
> The tests are a bit more complex. There are a bunch of existing JDI 
> tests for testing debugging support. Rather than start from scratch or 
> clone them, I instead just wrote wrapper tests that put the relevant 
> JDI test classes in the archive, and then invoke the JDI test. I did 
> this for 3 of the JDI tests. If you feel there are others that would 
> be good candidates, I'd be happy to add them. I'm looking for ones 
> that would result in modification of the RO class metadata, such as 
> setting a breakpoint (for which I already added two tests).
> Testing done:
> -Using JPRT to run the new jtreg tests on all platforms.
> -Using JPRT to run all jtreg runtime tests on linux x86 and x_64.
> -Regular JPRT "-testset hotspot" run
> -Putting the JCK JVMTI tests in the archive and then running them.
> -Putting the nsk jdb, jdwp, jvmti, and jdi tests in the archive and 
> then running them.
> -Putting a simple test class in the archive and then setting a 
> breakpoint on it using jdb
> Some of the above testing resulted in the discovery of bugs that still 
> need to be addressed: JDK-8078644, JDK-8078730, and JDK-8079181.
> I also verified that without the change to map the archive RW, the 
> above testing resulted in a SEGV, which is what you would expect (and 
> actually want to see to prove that the testing is effective).
> thanks,
> Chris

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