RFR(M): optional flattening - interpreter/runtime part

[Frederic Parain]

Here’s an updated webrev:

http://cr.openjdk.java.net/~fparain/optional-flattening-push/webrev.02/index.html

Changes:
  - code has been updated according to the recent interpreter changes
  - the issue with oop_map generation in layout_fields() has now a correct fix
  - A test in ValueOops has been commented because it has to be revisited
    with the introduction of optional flattening, but I’d like to discuss this topic
    with David Simms on a different CR.

Thank you,

Fred


> On Sep 14, 2017, at 11:03, Tobias Hartmann <tobias.hartmann at oracle.com> wrote:
> 
> Hi Fred,
> 
> I've just verified that the problem is solved with your latest webrev!
> 
> Thanks,
> Tobias
> 
> On 14.09.2017 16:50, Frederic Parain wrote:
>> Tobias,
>> Thank you for catching that.
>> There’s a bug in the layout computation, optional flattening code moves non-flattened
>> values from the value types section of the layout to the nonstatic_oop section, but the size
>> of the later was not updated accordingly.
>> Here’s an updated webrev fixing this issue:
>> http://cr.openjdk.java.net/~fparain/optional-flattening-interp/webrev.01/index.html
>> Regards,
>> Fred
>>> On Sep 14, 2017, at 03:46, Tobias Hartmann <tobias.hartmann at oracle.com> wrote:
>>> 
>>> Hi Fred,
>>> 
>>> there seems to be a problem with the field layout:
>>> 
>>> compiler.valhalla.valuetypes.MyValue1: field layout
>>>  @ 16 --- instance fields start ---
>>>  @ 24 "x" I
>>>  @ 16 "y" J
>>>  @ 32 "z" S
>>>  @ 40 "o" Ljava.lang.Integer;
>>>  @ 48 "oa" [I
>>>  @ 56 "v1" Qcompiler.valhalla.valuetypes.MyValue2;
>>>  @ 64 "v2" Qcompiler.valhalla.valuetypes.MyValue2;
>>>  @ 28 "c" I
>>>  @ 56 --- instance fields end ---
>>>  @ 56 --- instance ends ---
>>>  @176 --- static fields start ---
>>>  @192 "s" I
>>>  @184 "sf" J
>>>  @176 "v3" Qcompiler.valhalla.valuetypes.MyValue2;
>>>  @200 --- static fields end ---
>>> 
>>>  OopMapBlocks:   1  /  4
>>>    Offset:  40  - 64 Count:   4
>>> 
>>> "instance fields end" points to offset 56 which is not correct because the non-flattened field v2 is at offset 64.
>>> 
>>> Thanks,
>>> Tobias
>>> 
>>> On 13.09.2017 21:41, Frederic Parain wrote:
>>>> Greetings,
>>>> Please review this changeset implementing optional field flattening
>>>> in the interpreter and the runtime. The support for C2 is provided by
>>>> Tobias in a separate changeset.
>>>> http://cr.openjdk.java.net/~fparain/optional-flattening-interp/webrev.00/index.html
>>>> Note that trying to run some programs/tests with this changeset and
>>>> not Tobias’ changeset is likely to cause crashes unless interpreted mode
>>>> is forced and passing/returning values in registers is disabled.
>>>> Thank you,
>>>> Fred