RFR: 8062247: Allow WhiteBox test to access JVM offsets

[Mikhailo Seledtsov]

Looks good to me.

Misha

On 11/3/2014 4:11 PM, Yumin Qi wrote:
> I have made change to the function name in WhiteBox.
> New webrev at
>
> http://cr.openjdk.java.net/~minqi/8062247/webrev01/
>
> The function getOffsetForName(String name), takes a form of 
> "FileMapHead::_magic" as in vm, if there is no name present in vm for 
> search its offset, a RuntimeExcetion with message "<offsetname> not 
> found" will be thrown.
>
> tests: JPRT, jtreg
>
> Thanks
> Yumin
>
>
> On 11/3/2014 1:34 PM, Mikhailo Seledtsov wrote:
>> Yumin,
>>
>>  OK, I see you chose to pass the name of the struct implicitly 
>> instead of using an explicit parameter. I have no strong objection to 
>> that.
>> Please make sure to clarify this in the comments.
>>
>> Thank you,
>> Misha
>>
>> On 11/3/2014 1:15 PM, Yumin Qi wrote:
>>> If you check the name passed to this function, it already told (I 
>>> just changed to getOffsetForName and in testing):
>>>
>>> wb.getOffsetForName("FileMapHeader::_crc")
>>>
>>> Do not need to give type info(that will need build a list for type 
>>> info like in vmStructs). This is a simple code fore testing purpose, 
>>> I think we should keep it simple. I added that if the offsetname not 
>>> supported, throw exception instead. Will post webrev today after 
>>> jprt finished.
>>>
>>> Thanks
>>> Yumin
>>>
>>> On 11/3/2014 12:05 PM, Mikhailo Seledtsov wrote:
>>>> Hi Yumin,
>>>>
>>>>  If this API is intended to get offsets for various data 
>>>> structures, I would expect a data  structure type identified to be 
>>>> passed as a parameter. For instance,
>>>>
>>>> public native int getOffset(String dataStructureId, String fieldName)
>>>>     where
>>>>         dataStructureId would be some kind of ID for data 
>>>> structure, either data structure name or internal alias
>>>>         fieldName - the name of the field for which the offset 
>>>> value is returned
>>>>       A specific error code could be returned for unsupported 
>>>> dataStructureId
>>>>
>>>> Alternatively, this could be an API specific to a given 
>>>> data-structure. E.g. getMySpecifiedDatastructOffset(String fieldName)
>>>>
>>>> Thank you,
>>>> Misha
>>>>
>>>>
>>>> On 11/2/2014 9:52 PM, Yumin Qi wrote:
>>>>> Misha,
>>>>>
>>>>>   It is a generic name, now it only targets on FileMapHeader, it 
>>>>> can add other data structure of vm if needed in future. Maybe a 
>>>>> name like getOffsetForName(String name) is better?
>>>>>
>>>>> Thanks
>>>>> Yumin
>>>>>
>>>>> On 10/31/2014 11:56 AM, Mikhailo Seledtsov wrote:
>>>>>> Hi Yumin,
>>>>>>
>>>>>>  The name getOffsets() seems too generic. Perhaps, we could 
>>>>>> rename it to be more specific to the task.
>>>>>>
>>>>>> Thank you,
>>>>>> Misha
>>>>>>
>>>>>> On 10/29/2014 5:46 PM, Yumin Qi wrote:
>>>>>>> Please review the new changeset at same location.
>>>>>>> New API supply an interface to get data member offset by it's name.
>>>>>>> http://cr.openjdk.java.net/~minqi/8062247/webrev00/
>>>>>>>
>>>>>>> Thanks
>>>>>>> Yumin
>>>>>>>
>>>>>>> On 10/27/2014 9:01 PM, Yumin Qi wrote:
>>>>>>>> Please review
>>>>>>>>
>>>>>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8062247
>>>>>>>> webrev: http://cr.openjdk.java.net/~minqi/8062247/webrev00/
>>>>>>>>
>>>>>>>> Summary: Internal test failed since the variable offsets 
>>>>>>>> changed in hotspot. The way to get offset in the test is 
>>>>>>>> hard-coded. To reduce the risk of future changes of hotspot 
>>>>>>>> offsets, the fix add a WhiteBox API function to get a map for 
>>>>>>>> FileMapHeaderInfo, which return the members' offsets in a 
>>>>>>>> Hashtable.
>>>>>>>>
>>>>>>>> Tests: JPRT, jtreg.
>>>>>>>>
>>>>>>>> Thanks
>>>>>>>> Yumin
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>