RFR: 8232592: <Unknown compiled code> is shown in jstack mixed mode

[Chris Plummer]

Hi Yasumasa,

Looks good.

thanks,

Chris

On 10/21/19 7:02 PM, Yasumasa Suenaga wrote:
> Hi Chris,
>
> Thanks for your comment! I uploaded new webrev:
>
>   http://cr.openjdk.java.net/~ysuenaga/JDK-8232592/webrev.01/
>
>
>> So what does it mean if it is an NMethod but is not native and names 
>> != null. Should this ever happen? It seems odd that we don't print 
>> out the frame type in this case, and also don't call printUnknown().
>
> I guess it might happen when call nmethod from JNI.
> It would be handled as valid compiled code.
>
> ```
>  166                       // print java frames, if any
>  167                       if (names != null && names.length != 0) {
>  168                          // print java frame(s)
>  169                          for (int i = 0; i < names.length; i++) {
>  170                              out.println(names[i]);
>  171                          }
>  172                       }
>  ```
>
>
> Thanks,
>
> Yasumasa
>
>
> On 2019/10/22 2:25, Chris Plummer wrote:
>> Hi Yasumasa,
>>
>> The call to getJavaNames() is not needed if the method is native. It 
>> should be moved into the else block:
>>
>>                              if (cb.isNMethod()) {
>>                                 if (cb.isNativeMethod()) {
>> out.print(((CompiledMethod)cb).getMethod().externalNameAndSignature());
>>                                    long diff = pc.minus(cb.codeBegin());
>>                                    if (diff != 0L) {
>>                                      out.print(" + 0x" + 
>> Long.toHexString(diff));
>>                                    }
>>                                    out.println(" (Native method)");
>>                                 } else {
>>                                     names = getJavaNames(th, 
>> f.localVariableBase());
>>                                     if (names == null || names.length 
>> == 0) {
>>                                         // just print compiled code, 
>> if can't determine method
>> out.println("<Unknown compiled code>");
>>                                     }
>>                                 }
>>                              } else if (cb.isBufferBlob()) {
>>
>> So what does it mean if it is an NMethod but is not native and names 
>> != null. Should this ever happen? It seems odd that we don't print 
>> out the frame type in this case, and also don't call printUnknown().
>>
>> thanks,
>>
>> Chris
>>
>> On 10/18/19 1:38 AM, Yasumasa Suenaga wrote:
>>> Hi all,
>>>
>>> Please review this change.
>>>
>>>   JBS: https://bugs.openjdk.java.net/browse/JDK-8232592
>>>   webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8232592/webrev.00/
>>>
>>> I run `jhsdb jstack --mixed` to JShellToolProvider process, then I 
>>> saw <Unknown compiled code>
>>> in the stack as below:
>>>
>>> ```
>>> "process reaper" #13 daemon prio=10 tid=0x00007f959c328000 
>>> nid=0x1285 runnable [0x00007f9578025000]
>>>    java.lang.Thread.State: RUNNABLE
>>>    JavaThread state: _thread_in_native
>>> 0x00007f95a27c5596 __waitpid + 0x56
>>> 0x00007f958c601d79 <Unknown compiled code>
>>> 0x00007f9585c5b4ac * java.lang.ProcessHandleImpl$1.run() bci:8 
>>> line:138 (Compiled frame)
>>> ```
>>>
>>> 0x7f958c601d79 is native method. jstack mixed mode should handle it.
>>> This patch passed all tests on submit repo 
>>> (mach5-one-ysuenaga-JDK-8232592-20191018-0600-6011163).
>>>
>>>
>>> Thanks,
>>>
>>> Yasumasa
>>