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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 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.