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Diffstat (limited to 'ChangeLog')
| -rw-r--r-- | ChangeLog | 44 |
1 files changed, 44 insertions, 0 deletions
@@ -1,3 +1,47 @@ +Tue Dec 18 06:36:12 2012 Koichi Sasada <ko1@atdot.net> + + * 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. + Tue Dec 18 04:58:22 2012 Koichi Sasada <ko1@atdot.net> * vm_trace.c (fill_id_and_klass): TracePoint#defined_class returns |