RFR: 8010278 SA: provide mechanism for using an alternative SA debugger back-end.

[Staffan Larsen]

On 24 jun 2013, at 11:20, Staffan Larsen <staffan.larsen at oracle.com> wrote:

> 
> On 19 jun 2013, at 14:40, Kevin Walls <kevin.walls at oracle.com> wrote:
> 
>> 
>> Hi Staffan --
>> 
>> And apologies from me for the slow turnaround. 8-)
>> 
>> Thanks for the suggestions, implementing them all.
> 
> Thanks.
> 
>> 
>> http://cr.openjdk.java.net/~kevinw/8010278/webrev.02/
>> 
>> Also adding the same kind of change to the HSDB tool, a few changes there to get the gui closing without using System.exit.
> 
> So how do I now exit the HSDB tool? Closing the window won't exit. File->Exit won't exit. Or did I miss something?

I did miss that the workerThread is also terminated in closeUI() and that causes the app to exit.

This looks good. Reviewed.

/Staffan

> 
> /Staffan
> 
>> 
>> Additional feedback gratefully received...
>> 
>> Thanks
>> Kevin
>> 
>> 
>> On 05/06/13 12:00, Staffan Larsen wrote:
>>> Some comments (sorry it took so long):
>>> 
>>> CLHSDB.java
>>> - Can you move the jvmDebugger field to where the other fields are in the class? Make it private, too.
>>> - Remove start() and make run() public?
>>> - Perhaps improve on the comment in run() saying that either jvmDebugger OR pidText OR {execPath, coreFileName} should be set.
>>> 
>>> HotspotAgent.java
>>> - Should sa.altHotSpotAgent be called sa.altDebugger ?
>>> 
>>> Tool.java
>>> - Make jvmDebugger private.
>>> 
>>> 
>>> Regards,
>>> /Staffan
>>> 
>>> 
>>> 
>>> 
>>> On 23 maj 2013, at 15:23, Kevin Walls<kevin.walls at oracle.com>  wrote:
>>> 
>>>> Forgot to mention:
>>>> 
>>>> I moved the ClassDump Tool around a little so it was usable via a route other than calling main(), and added the constructor that takes a String for the pkgList, which saves using the system property to communicate what classes you want to dump (sun.jvm.hotspot.tools.jcore.PackageNameFilter has that constructor already).
>>>> 
>>>> Actually, considering the package filter name is always going to be sun.jvm.hotspot.tools.jcore.PackageNameFilter, let's have that as a default value when we call getProperty.  Similarly the getProperty for outputDir, and at that point I stop tweaking.
>>>> 
>>>> A little indenting was off also and I added a comment, so I redid the webrev:
>>>> 
>>>> http://cr.openjdk.java.net/~kevinw/8010278/webrev.01/
>>>> 
>>>> Thanks
>>>> Kevin
>>>> 
>>>> 
>>>> 
>>>> On 23/05/13 11:00, Kevin Walls wrote:
>>>>> Hi,
>>>>> 
>>>>> As the Serviceability Agent has been _the_ new and interesting way to find things post-mortem in the JVM [1], I'd like to propose an update which continues that tradition.
>>>>> 
>>>>> 8010278 SA: provide mechanism for using an alternative SA debugger back-end.
>>>>> https://jbs.oracle.com/bugs/browse/JDK-8010278
>>>>> http://cr.openjdk.java.net/~kevinw/8010278/webrev.00/
>>>>> 
>>>>> This is about making the SA more flexible, so we aren't tied to the given native libraries to open cores/memory dumps.  Given this change, a 3rd party debugger or tool can interact freely with the SA tools (StackTrace, ObjectHistogram, etc...) and provide its own backend implementation to actually open a core/memory dump.
>>>>> 
>>>>> Primarily for platform-independent core file debugging.  If you ever had to open a "foreign" core, find the right hardware, etc... this is relevant.   I'm thinking of https://java.net/projects/kjdb which can serve as a proof of concept.
>>>>> 
>>>>> The changes are:
>>>>> 
>>>>> The main redirection is in HotSpotAgent.java, where we respect a property (i.e. -Dsa.altHotSpotAgent=...) to name an alternate debugger.
>>>>> 
>>>>> Remove calls to System.exit.
>>>>> 
>>>>> Tool classes (and CLHSDB) should have a constructor that takes a JVMDebugger, to remove the assumption that a Tool's JVM will only ever contain one debugee.  It doesn't address that VM is a singleton and if a tool opens multiple sessions then they would need to be from the same JVM version.
>>>>> 
>>>>> 
>>>>> Thanks
>>>>> Kevin
>>>>> 
>>>>> [1]  If you weren't in a circa 1.4.2 demo of the SA when all you had previously was a few fragile dbx macros, that got you a few very specific details, the night vs. day comparison of no SA vs. SA could be missed. 8-)
>>>>> 
>>>>> 
>> 
>