> On Dec 2, 2020, at 3:53 AM, Remi Forax <fo...@univ-mlv.fr> wrote: > > Using a condy that returns a String instead of a method descriptor in the > bytecode ? > I'm currently trying to remove the uses of Unsafe.defineAnonymousClass to use > Lookup.defineHiddenClass instead. > There is one case where i dynamically patch a method descriptor so I can > select how many arguments will be sent to a closure, > i.e. in the bytecode i put all arguments on the stack but because i've > patched the callee descriptor, only some of them will be used. > > I see defineAnonymousClass has a way to push data to a template class file > and defineHiddenClass has a way to pull the data from the template class file. > But i can not currently pull data that will be used by a NameAndType info > because the descriptor_index has to be a Constant_Utf8 index and can not be a > condy with a String as descriptor.
The trouble I see with changing NameAndType is that verification needs a static string. At that stage, it's too early to be resolving condys. > This is related to Lazy static final field [1] and also to class templating > in general because it equivalent to seeing all the template holes as condy > even if it"s less efficient because you need to duplicate the whole constant > pool. Lazy static fields, if I understand the proposal correctly, use a condy to determine the _value_ of the field, but not its _type_. Linkage behavior is unchanged. Similarly, our preferred story for templating right now is to use normal Utf8 strings for descriptors, and give each species different side-channel type information, computed via condy. This side information is needed fairly early, but verification is entirely descriptor-string-based.
