RFR(M): 8236913: debug agent's jdwp command logging should include the command set name and command name

[Chris Plummer]

Hi Alex,

Are you ok with the _p arguments?

Also, can I get a second reviewer please.

thanks,

Chris

On 1/10/20 3:00 PM, Chris Plummer wrote:
> Hi Alex,
>
> I'll fix the mistakes in MethodImpl.c and ReferenceTypeImpl.c. As for 
> the "_p" suffix, it means the argument is a pointer type that a value 
> will be returned in. I've seen this used elsewhere in hotspot. For 
> example VM_RedefineClasses::merge_constant_pools() and 
> ObjectSynchronizer::deflate_monitor_list().
>
> bool VM_RedefineClasses::merge_constant_pools(const 
> constantPoolHandle& old_cp,
>        const constantPoolHandle& scratch_cp, constantPoolHandle 
> *merge_cp_p,
>        int *merge_cp_length_p, TRAPS) {
>
> int ObjectSynchronizer::deflate_monitor_list(ObjectMonitor** list_p,
>                                              ObjectMonitor** free_head_p,
>                                              ObjectMonitor** 
> free_tail_p) {
>
> thanks,
>
> Chris
>
> On 1/10/20 2:12 PM, Alex Menkov wrote:
>> Hi Chris,
>>
>> Thanks for making the code more "typed" (this "void*" arrays are 
>> error prone).
>> Looks good in general, some minor comments:
>>
>> MethodImpl.c
>> - command names starts with lower case letters
>>
>>
>> ReferenceTypeImpl.c
>> - please fix indentation for command definitions
>>
>>
>> debugDispatch.h/.c
>>
>> +debugDispatch_getHandler(int cmdSetNum, int cmdNum, const char 
>> **cmdSetName_p, const char **cmdName_p)
>>
>> What are the "_p" suffixes for? to show that this are pointers?
>> To me this doesn't make much sense.
>>
>> --alex
>>
>> On 01/10/2020 11:27, Chris Plummer wrote:
>>> Hello,
>>>
>>> Please review the following
>>>
>>> https://bugs.openjdk.java.net/browse/JDK-8236913
>>> http://cr.openjdk.java.net/~cjplummer/8236913/webrev.00/
>>>
>>> The debug agent has logging support that will trace all jdwp 
>>> commands coming in. Currently all it traces is the command set 
>>> number and the command number within that command set. So you see 
>>> something like:
>>>
>>> [#|10.01.2020 06:27:24.366 
>>> GMT|FINEST|J2SE1.5|jdwp|LOC=MISC:"debugLoop.c":240;;PID=12719;THR=t at 915490560|:Command 
>>> set 1, command 9|#]
>>>
>>> I've added support for including the name of the command set and 
>>> command, so now you see:
>>>
>>> [#|10.01.2020 06:27:24.366 
>>> GMT|FINEST|J2SE1.5|jdwp|LOC=MISC:"debugLoop.c":240;;PID=12719;THR=t at 915490560|:Command 
>>> set VirtualMachine(1), command Resume(9)|#]
>>>
>>> So in this case command set 1 represents VirtualMachine and command 
>>> 9 is the Resume command.
>>>
>>> I was initially going to leverage jdwp.spec which is already 
>>> processed by build.tools.jdwpgen.Main to produce JDWP.java and 
>>> JDWPCommands.h. However, I could see it was more of a challenge than 
>>> I initially hoped. Also, the main advantage would have been not 
>>> having to hard code arrays of command names, but we already have 
>>> harded coded arrays of function pointers to handle the various jdwp 
>>> commands, so I just replaced these with a more specialized arrays 
>>> that also include the names of the commands. As an example, we used 
>>> to have:
>>>
>>> void *ArrayReference_Cmds[] = { (void *)0x3
>>>      ,(void *)length
>>>      ,(void *)getValues
>>>      ,(void *)setValues};
>>>
>>> Now we have:
>>>
>>> CommandSet ArrayReference_Cmds = {
>>>      3, "ArrayReference",
>>>      {
>>>          {length, "Length"},
>>>          {getValues, "GetValues"},
>>>          {setValues, "SetValues"}
>>>      }
>>> };
>>>
>>> So no worse w.r.t. hard coding things that could be generated off 
>>> the spec, and it cleans up some ugly casts also. The CommandSet 
>>> typedef can be found in debugDispatch.h.
>>>
>>> All the header files except for debugDispatch.h have the same 
>>> pattern for changes, so they are pretty easy to review
>>>
>>> All .c files except debugDispatch.c and debugLoop.c also have the 
>>> same pattern. Note some command handler function names are not the 
>>> same as the command name. If you want to double check command set 
>>> names and command names, you can find the spec here:
>>>
>>> https://docs.oracle.com/javase/9/docs/specs/jdwp/jdwp-protocol.html
>>>
>>> In ReferenceTypeImpl.c I fixed a typo in the method() prototype. It 
>>> had an extra argument which I think was a very old copy-n-paste bug 
>>> from the method1() prototype. This was caught because the command 
>>> handler functions are now directly assigned to a CommandHandler type 
>>> rather than cast. The cast was hiding this bug.
>>>
>>> I tested by doing a test run where MISC logging was enabled by 
>>> default. All jdwp, jdb, and jdi tests were run in this way and passed.
>>>
>>> thanks,
>>>
>>> Chris
>>>
>
>