ruby-changes:26380
From: ko1 <ko1@a...>
Date: Tue, 18 Dec 2012 07:07:04 +0900 (JST)
Subject: [ruby-changes:26380] ko1:r38431 (trunk): * method.h: remove `VM_METHOD_TYPE_CFUNC_FRAMELESS' method type.
ko1 2012-12-18 07:04:12 +0900 (Tue, 18 Dec 2012) New Revision: 38431 http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=rev&revision=38431 Log: * 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. Modified files: trunk/ChangeLog trunk/method.h trunk/proc.c trunk/vm_eval.c trunk/vm_insnhelper.c trunk/vm_method.c Index: method.h =================================================================== --- method.h (revision 38430) +++ method.h (revision 38431) @@ -53,7 +53,6 @@ typedef enum { https://github.com/ruby/ruby/blob/trunk/method.h#L53 VM_METHOD_TYPE_NOTIMPLEMENTED, VM_METHOD_TYPE_OPTIMIZED, /* Kernel#send, Proc#call, etc */ VM_METHOD_TYPE_MISSING, /* wrapper for method_missing(id) */ - VM_METHOD_TYPE_CFUNC_FRAMELESS, VM_METHOD_TYPE_REFINED, END_OF_ENUMERATION(VM_METHOD_TYPE) Index: ChangeLog =================================================================== --- ChangeLog (revision 38430) +++ ChangeLog (revision 38431) @@ -1,3 +1,47 @@ https://github.com/ruby/ruby/blob/trunk/ChangeLog#L1 +Tue Dec 18 06:36:12 2012 Koichi Sasada <ko1@a...> + + * 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@a...> * vm_trace.c (fill_id_and_klass): TracePoint#defined_class returns Index: vm_eval.c =================================================================== --- vm_eval.c (revision 38430) +++ vm_eval.c (revision 38431) @@ -219,12 +219,6 @@ vm_call0_body(rb_thread_t* th, rb_call_i https://github.com/ruby/ruby/blob/trunk/vm_eval.c#L219 rb_bug("vm_call0: unsupported optimized method type (%d)", ci->me->def->body.optimize_type); } break; - case VM_METHOD_TYPE_CFUNC_FRAMELESS: - { - /* TODO: can optimize it */ - const rb_method_cfunc_t *cfunc = &ci->me->def->body.cfunc; - return cfunc->invoker(cfunc->func, ci->recv, ci->argc, argv); - } case VM_METHOD_TYPE_UNDEF: break; } Index: proc.c =================================================================== --- proc.c (revision 38430) +++ proc.c (revision 38431) @@ -1651,7 +1651,6 @@ rb_method_entry_arity(const rb_method_en https://github.com/ruby/ruby/blob/trunk/proc.c#L1651 const rb_method_definition_t *def = me->def; if (!def) return 0; switch (def->type) { - case VM_METHOD_TYPE_CFUNC_FRAMELESS: case VM_METHOD_TYPE_CFUNC: if (def->body.cfunc.argc < 0) return -1; Index: vm_method.c =================================================================== --- vm_method.c (revision 38430) +++ vm_method.c (revision 38431) @@ -420,7 +420,6 @@ rb_add_method(VALUE klass, ID mid, rb_me https://github.com/ruby/ruby/blob/trunk/vm_method.c#L420 def->body.iseq = (rb_iseq_t *)opts; break; case VM_METHOD_TYPE_CFUNC: - case VM_METHOD_TYPE_CFUNC_FRAMELESS: { rb_method_cfunc_t *cfunc = (rb_method_cfunc_t *)opts; setup_method_cfunc_struct(&def->body.cfunc, cfunc->func, cfunc->argc); Index: vm_insnhelper.c =================================================================== --- vm_insnhelper.c (revision 38430) +++ vm_insnhelper.c (revision 38431) @@ -1620,21 +1620,6 @@ vm_call_opt_call(rb_thread_t *th, rb_con https://github.com/ruby/ruby/blob/trunk/vm_insnhelper.c#L1620 } static VALUE -vm_call_cfunc_frameless_unary(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci) -{ - cfp->sp -= 1; - return (*ci->me->def->body.cfunc.func)(ci->recv); -} - -static VALUE -vm_call_cfunc_frameless_binary(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci) -{ - VALUE obj = *cfp->sp; - cfp->sp -= 2; - return (*ci->me->def->body.cfunc.func)(ci->recv, obj); -} - -static VALUE vm_call_method_missing(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci) { VALUE *argv = STACK_ADDR_FROM_TOP(ci->argc); @@ -1748,20 +1733,6 @@ vm_call_method(rb_thread_t *th, rb_contr https://github.com/ruby/ruby/blob/trunk/vm_insnhelper.c#L1733 } break; } - case VM_METHOD_TYPE_CFUNC_FRAMELESS: - switch (ci->me->def->body.cfunc.argc) { - case 0: - rb_check_arity(ci->argc, 0, 0); - CI_SET_FASTPATH(ci, vm_call_cfunc_frameless_unary, enable_fastpath && !(ci->flag & VM_CALL_ARGS_SPLAT)); - return vm_call_cfunc_frameless_unary(th, cfp, ci); - case 1: - rb_check_arity(ci->argc, 0, 1); - CI_SET_FASTPATH(ci, vm_call_cfunc_frameless_binary, enable_fastpath && !(ci->flag & VM_CALL_ARGS_SPLAT)); - return vm_call_cfunc_frameless_binary(th, cfp, ci); - default: - rb_bug("vm_call_method: unsupported cfunc_fast argc (%d)", ci->me->def->body.cfunc.argc); - } - break; case VM_METHOD_TYPE_UNDEF: break; case VM_METHOD_TYPE_REFINED:{ -- ML: ruby-changes@q... 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