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

[Karen Kinnear]

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
>