RFR: 8013635 Lambda: vm conditionally create bridges for generic signatures

[Karen Kinnear]

Many thanks - especially since you know this code better than I do :-)
And it is much better now due to Coleen and Serguei's review comments.

thanks,
Karen

On Jun 27, 2013, at 11:34 AM, Bharadwaj Yadavalli wrote:

> 
> The updated version looks good.
> 
> Thanks,
> 
> Bharadwaj
> 
> On 6/26/2013 10:52 PM, Karen Kinnear wrote:
>> Coleen,
>> 
>> I so appreciate the detailed review - many thanks!
>> 
>> Updated webrev:
>> 
>> http://cr.openjdk.java.net/~acorn/8013635.2/webrev/
>> 
>> tested: with javac and metafactory changes:
>> defmeth tests,
>> jtreg jdk.util in progress
>> vm.quick.testlist in progress
>> 
>> On Jun 25, 2013, at 1:48 PM, Coleen Phillimore wrote:
>> 
>>> Karen,
>>> 
>>> http://cr.openjdk.java.net/~acorn/8013635.1/webrev/src/share/vm/classfile/defaultMethods.cpp.frames.html
>>> 
>>> If someone calls this version of print_on(), won't it call the one at 440 and then crash because signature is null?
>>> 
>>> 437   void print_on(outputStream* str) const {
>>> 438     print_on(str, 0);
>>> 439   }
>>> 
>> Good catch.
>> This is messier than I wanted - so I refactored and renamed some of the print_on's.
>>> Shouldn't it just be removed?
>>> 
>>> You could rename "curslotidx" to current_slot_index...
>> Done.
>>> 774     InstanceKlass* sub = current_depth() > 0 ? class_at_depth(1) : NULL;
>>> 
>>> Variable sub is not used.
>> Removed.
>>> ShadowChecker::path_has_shadow() should be pure virtual because if you don't override ShadowChecker the visit function will never find a shadow.  line 1088.
>>> 
>> Yes - thank you.
>>> 1109       InstanceKlass* sub = class_at_depth(i + 1);
>>> 
>>> Variable 'sub' is not used here (trying to understand this).
>> Removed - sorry - left over from the refactoring.
>>> 1097 // Only called if the resolved_klass is a direct superinterface of
>>> 1098 // the caller's class.
>>> 
>>> 
>>> This comment seems out of context, in that which is resolved_klass?   Should this comment be in the caller or the caller's caller.  It doesn't seem helpful here to understand what this is doing or why.   Except:
>> Removed - and clarified "...candidates which are methods in immediate superinterfaces" - which
>> the caller already checks for
>>> 1111       if (ik->is_interface()) {
>>> 
>>> And why does this only check for if an interface class shadows the method?  I thought a method of a non-interface class can also shadow a method?
>> We are walking up the superinterfaces, so once you get to an interface, the only non-superinterface is j.l.Object which shouldn't
>> be providing default methods.
>>> 1307   if (!direction->is_interface()) {
>>> 1308     // We should not be here
>>> 1309     return NULL;
>>> 1310   }
>>> 
>>> Should this be an assert instead?   The caller of find_super_default won't be happy to get a NULL back without an exception pending.
>> Good catch. Changed to assert, and renamed "direction" to super_class.
>>> I don't have any other comments.  This looks good!
>>> 
>>> Coleen
>> And thanks for the detailed discussion,
>> Karen
>>> 
>>> On 06/20/2013 04:18 PM, Karen Kinnear wrote:
>>>> Please review:
>>>> https://jbs.oracle.com/bugs/browse/JDK-8013635: BridgeMethodsLinearTest.java fails in
>>>> Lambda nightly runs
>>>> 
>>>> webrev: http://cr.openjdk.java.net/~acorn/8013635.1/webrev/
>>>> 
>>>> This particular set of changes modifies the vm to conditionally handle generic signatures
>>>> when processing default methods. Basically this code refactors the defaultMethods logic
>>>> to work either with generic signatures or only with erased signatures.
>>>> 
>>>> The flag: ParseGenericDefaults is set to "true" in this webrev to continue to work with
>>>> the current javac and lambda metafactory components.
>>>> 
>>>> The intention is to change ParseGenericDefaults to false and simultaneously change
>>>> javac to generate bridges to handle generic signatures in interface methods, and
>>>> the metafactory to no longer generate bridges.
>>>> With the flag change, the vm will no longer generate bridges for generic
>>>> signatures.
>>>> 
>>>> A subsequent fix: 8012294 will completely remove the vm generic interface handling
>>>> for jdk8.
>>>> 
>>>> Please approve this change with both flag settings, so we can coordinate making
>>>> those changes in the order that is least disruptive.
>>>> 
>>>> Testing:
>>>> 
>>>> I. hotspot-rt: ParseGenericDefaults=true:
>>>> jprt
>>>> vm.quick.testlist
>>>> jdk-jtreg - in progress
>>>> jck-lang, vm - in progress
>>>> 
>>>> II. Lambda repo: ParseGenericDefaults=false:
>>>> These two files, with other changes not currently needed - tested in lambda repository for a month
>>>>    including tl nightlies and updated BridgeMethodsLinearTest
>>>> 
>>>> III. Current hotspot-rt with these two files only and ParseGenericDefaults=false
>>>> with jdk8tl repository with 8015402: metafactory changes and 8013789: javac changes:
>>>> 
>>>> vm.quick.testlist - in progress
>>>> jdk-jtreg - in progress
>>>> jck-lang, vm - in progress
>>>> 
>>>> thanks,
>>>> Karen
>