[foreign] RFR 8222765: Implement foreign memory access through VarHandle

[Maurizio Cimadamore]

Here's a new revision based on some comments from Jorn:

* revised VarHandle templating logic - now there's a single 
VarHandleMemoryAddressBase declared in j.l.i package

* added more carrier checks to VarHandles::makeMemoryAddressViewHandle 
(and test)

* made layout lookup logic uniform between values and group (before, 
group lookup would not check if the group itself matched the condition)

http://cr.openjdk.java.net/~mcimadamore/panama/8222765_v3/webrev/

Maurizio


On 19/04/2019 21:48, Maurizio Cimadamore wrote:
> Fixed the template:
>
> http://cr.openjdk.java.net/~mcimadamore/panama/8222765_v2/
>
> I'd prefer to address the API issues in follow up issues, as we keep 
> going through the API (also with Brian and others).
>
> Cheers
> Maurizio
>
> On 19/04/2019 20:07, Jorn Vernee wrote:
>> AFAIK it ensures that there is a unique name for the variables used 
>> in the macro.
>>
>> e.g. if t = Byte then $1_Type expands to 
>> VAR_HANDLE_BYTE_ARRAY_Byte_Type, as variable name. But, this 
>> currently conflicts with the GenerateVarHandleByteArray macro for 
>> some types.
>>
>> Jorn
>>
>> Maurizio Cimadamore schreef op 2019-04-19 19:55:
>>> After a closer look, it seems like the first parameter to the macro is
>>> not used. The macro GenerateVarHandleXYZ does, as its first thing:
>>>
>>> $1_Type := $2
>>>
>>> And then keeps using $1_Type after that.
>>>
>>> Maybe the $1 parameter is some remains of older code.
>>>
>>> Maurizio
>>> On 19/04/2019 17:42, Maurizio Cimadamore wrote:
>>>
>>>> On 19/04/2019 16:46, Jorn Vernee wrote:
>>>>
>>>>> - In GensrcVarHandles.gmk you seem to have a mistake in the
>>>>> generation command:
>>>>>
>>>>> 274 # List the types to generate source for, with capitalized
>>>>> first letter
>>>>> 275 VARHANDLES_MEMORY_ADDRESS_TYPES := Byte Short Char Int Long
>>>>> Float Double
>>>>> 276 $(foreach t, $(VARHANDLES_MEMORY_ADDRESS_TYPES), \
>>>>> 277   $(eval $(call
>>>>> GenerateVarHandleMemoryAddress,VAR_HANDLE_BYTE_ARRAY_$t,$t)))
>>>>>
>>>>> You still have to change the name VAR_HANDLE_BYTE_ARRAY_ to
>>>>> something else (probably forgotten when copy pasting?)
>>>> Good point, I wonder why it  still works??? I'll take another look.
>>>> The right classes are definitively generated.