[foreign] RFR: Debug code for UniversalUpcallHandler

[Jorn Vernee]

They are pretty similar, but CallingSequence::asString doesn't actually 
print out the values of the arguments, it's more of a "which argument 
goes where" type of deal.

UpcallContext actually holds the values of the arguments, so in the case 
of UpcallContext::asString we dump the actual value of the arguments.

Does that make sense?

Jorn

Maurizio Cimadamore schreef op 2018-12-18 01:35:
> Question: why is UniversalUpcallHandler::asString duplicating the
> CallSequence::asString code (instead of delegating to it)?
> 
> Maurizio
> 
> On 18/12/2018 00:16, Jorn Vernee wrote:
>> Hi,
>> 
>> I have one more piece of debugging code from my Windows porting 
>> experience that I thought might be useful to have.
>> 
>> This adds to the debugging code already in UniversalUpcallHandler to 
>> also output the incoming and outgoing UpcallContext and Java 
>> arguments/returns. e.g. this is for a qsort comparator call:
>> 
>> ```
>> === UpcallHandler.invoke ===
>> CallingSequence: {
>>   returnsInMemory: false
>>   Classes:
>>     STACK_ARGUMENT_SLOT
>>     VECTOR_ARGUMENT_REGISTER
>>     INTEGER_ARGUMENT_REGISTER
>>       Storage { INTEGER_ARGUMENT_REGISTER[0] (size=8) } : arg0 @ 0x0
>>       Storage { INTEGER_ARGUMENT_REGISTER[1] (size=8) } : arg1 @ 0x0
>>     VECTOR_RETURN_REGISTER
>>     INTEGER_RETURN_REGISTER
>>       Storage { INTEGER_RETURN_REGISTER[0] (size=8) } : __retval @ 0x0
>>     X87_RETURN_REGISTER
>> }
>> 
>> UpcallContext:
>>   STACK_ARGUMENT_SLOT
>>   VECTOR_ARGUMENT_REGISTER
>>   INTEGER_ARGUMENT_REGISTER
>>     b0 4f 57 cb a0 02 00 00
>>     c4 4f 57 cb a0 02 00 00
>>   VECTOR_RETURN_REGISTER
>>   INTEGER_RETURN_REGISTER
>>     73 9e 21 af a0 02 00 00
>>   X87_RETURN_REGISTER
>> 
>> Java arguments:
>>   [{ BoundedPointer type: 
>> jdk.internal.foreign.memory.LayoutTypeImpl at 61064425 region: { 
>> BoundedMemoryRegion base=null, min=0x0 length=0x7fffffffffffffff 
>> mode=READ_WRITE } offset=0x2a0cb574fb0 }, { BoundedPointer type: 
>> jdk.internal.foreign.memory.LayoutTypeImpl at 61064425 region: { 
>> BoundedMemoryRegion base=null, min=0x0 length=0x7fffffffffffffff 
>> mode=READ_WRITE } offset=0x2a0cb574fc4 }]
>> 
>> Java return:
>>   1
>> 
>> Returning:
>>   UpcallContext:
>>     STACK_ARGUMENT_SLOT
>>     VECTOR_ARGUMENT_REGISTER
>>     INTEGER_ARGUMENT_REGISTER
>>       b0 4f 57 cb a0 02 00 00
>>       c4 4f 57 cb a0 02 00 00
>>     VECTOR_RETURN_REGISTER
>>     INTEGER_RETURN_REGISTER
>>       01 00 00 00 a0 02 00 00
>>     X87_RETURN_REGISTER
>> ```
>> 
>> This behaviour is guarded by the 
>> '-Djdk.internal.foreign.UpcallHandler.DEBUG=true' flag.
>> 
>> Webrev: 
>> http://cr.openjdk.java.net/~jvernee/panama/webrevs/univupcalldebug/webrev.03/
>> 
>> Let me know what you think!
>> 
>> Thanks,
>> Jorn
>> 
>> P.S. is it OK that I'm not making JIRA tickets for these?