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Revision 38431

  • method.h: remove VM_METHOD_TYPE_CFUNC_FRAMELESS' method type. This method type is for optimized CFUNC such as Fixnum#+ and so on. This feature is half-baked and no way to use them. [Background] Now, VM has opt_plus instructions to optimize+' methods for some Classes (such as Fixnum, Float (flonum)). We call this type of instructions as `specialized instructions'. This simple technique improve simple program dramatically. However, we can make specialized instructions for only several types (classes) and selectors (method names) because a large instruction will be slow. In other words, this technique has no extensibility. To overcome this problem, VM_METHOD_TYPE_CFUNC_FRAMELESS was introduced (r37198). This type is a variant of CFUNC, but called their functiions directly without building a method frame. Any CFUNC method can be defined as frameless methods if a method is not needed to make method frame. Frameless methods are faster as specialized instructions (a bit slower, but no need to care). No problem described at http://charlie.bz/blog/why-do-singleton-methods-make-ruby-slow because this technique doesn't see class, but see method body itself. Alias is also no problem. [Problem] However, we can't set frameless method type for polymorphic methods such as Array#[]. Necessity for method frame depends on which parameter type. For example, Fixnum#+ needs method frame if coerce is needed. Current VM_METHOD_TYPE_CFUNC_FRAMELESS is not flexible and need more tuning to introduce it. Expected behavior of frameless method type may be: result = optimized_cfunc(params); /* call optimized cfunc */ if (result == Qundef) { result = normal_cfunc(); } This is why I say this feature is half-baked. We need to learn primitive method in Smalltalk more. (I heard this name at RubyConf Taiwan this month. Thanks!) [Conclusion] Nobody may use this feature and there is no compatibility issue. This feature goes to next minor (2.1?).
  • proc.c (rb_method_entry_arity): ditto.
  • vm_eval.c, vm_insnhelper.c, vm_method.c: ditto.