> De: "Paul Sandoz" <paul.san...@oracle.com> > À: "John Rose" <john.r.r...@oracle.com> > Cc: "Rémi Forax" <fo...@univ-mlv.fr>, valhalla-spec-experts@openjdk.java.net > Envoyé: Mercredi 21 Juin 2017 20:24:52 > Objet: Re: notes from Valhalla meeting 5/24/17
>> On 21 Jun 2017, at 09:03, John Rose < john.r.r...@oracle.com > wrote: >> On Jun 21, 2017, at 8:46 AM, Remi Forax < fo...@univ-mlv.fr > wrote: >>> but i do not like with this proposal as is, i will explain why and how to >>> fix >>> it: >>> - condy is linked to a static final field but unlike invokedynamic which is >>> a >>> link from an invokedynamic instruction to a CONSTANT_InvokeDynamic_info, >>> there is no link from the static final field to the >>> CONSTANT_ConstantDynamic_info. >>> Why not reuse the ConstantValue attribute [1] to reference the >>> CONSTANT_ConstantDynamic_info instead (the constantvalue_index can be >>> extended >>> to allow a CONSTANT_ConstantDynamic). >>> - condy if a 'dy' like indy, so it should do late late binding, i.e. being >>> initialized (run the bootstrap method) only the first time someone access to >>> the static field exactly like with indy the bsm is called the first time you >>> try to access the instruction. >>> In term of semantics, my proposal does not introduce an item in the constant >>> pool which is resolved only by the virtue of being in the constant pool >>> unlike >>> any other items. If condy is linked to the ConstantValue of a field, the >>> condy >>> item is resolved when necessary as usual. With my ASM hat, i see how to >>> implement it easily without having to surface the constant pool itself (at >>> least until the items are pointed by the j.l.i.BootstrapCallInfo). >> Indeed, repurposing ConstantValue in the way you describe is an add-on to >> this >> proposal. > Can we get away with changing all static final fields to be lazily initialized > without some explicit opt-in? I think it's too late for Java (the language). As far as i remember, this is by default in Dart. > It would be nice but it might induce subtle changes in behaviour and > expectations (especially for where exceptions may occur). Also, the order of the side effects will be different and how you see non initialized field (when you have recursion) but introducing a new keyword like lazy or stable is possible. > Paul. Rémi >> I almost threw it in, but didn't want to muddy the basic proposal. >> In the basic proposal, condy is *not* linked to static finals. >> It only repurposes the concept of field names and field types >> (as if from Fieldref but not using Fieldref) but does not actually link to >> fields. >> — John
