vm_insnhelper.c

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/**********************************************************************

  vm_insnhelper.c - instruction helper functions.

  $Author: nagachika $

  Copyright (C) 2007 Koichi Sasada

**********************************************************************/

/* finish iseq array */
#include "insns.inc"
#include <math.h>
#include "constant.h"
#include "internal.h"
#include "probes.h"
#include "probes_helper.h"

/* control stack frame */

#ifndef INLINE
#define INLINE inline
#endif

static rb_control_frame_t *vm_get_ruby_level_caller_cfp(rb_thread_t *th, rb_control_frame_t *cfp);

static void
vm_stackoverflow(void)
{
    rb_exc_raise(sysstack_error);
}

static inline rb_control_frame_t *
vm_push_frame(rb_thread_t *th,
              const rb_iseq_t *iseq,
              VALUE type,
              VALUE self,
              VALUE klass,
              VALUE specval,
              const VALUE *pc,
              VALUE *sp,
              int local_size,
              const rb_method_entry_t *me,
              size_t stack_max)
{
    rb_control_frame_t *const cfp = th->cfp - 1;
    int i;

    /* check stack overflow */
    CHECK_VM_STACK_OVERFLOW0(cfp, sp, local_size + (int)stack_max);

    th->cfp = cfp;

    /* setup vm value stack */

    /* initialize local variables */
    for (i=0; i < local_size; i++) {
        *sp++ = Qnil;
    }

    /* set special val */
    *sp = specval;

    /* setup vm control frame stack */

    cfp->pc = (VALUE *)pc;
    cfp->sp = sp + 1;
#if VM_DEBUG_BP_CHECK
    cfp->bp_check = sp + 1;
#endif
    cfp->ep = sp;
    cfp->iseq = (rb_iseq_t *) iseq;
    cfp->flag = type;
    cfp->self = self;
    cfp->block_iseq = 0;
    cfp->proc = 0;
    cfp->me = me;
    if (klass) {
        cfp->klass = klass;
    }
    else {
        rb_control_frame_t *prev_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
        if (RUBY_VM_CONTROL_FRAME_STACK_OVERFLOW_P(th, prev_cfp)) {
            cfp->klass = Qnil;
        }
        else {
            cfp->klass = prev_cfp->klass;
        }
    }

    if (VMDEBUG == 2) {
        SDR();
    }

    return cfp;
}

static inline void
vm_pop_frame(rb_thread_t *th)
{
    th->cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(th->cfp);

    if (VMDEBUG == 2) {
        SDR();
    }
}

/* method dispatch */
static inline VALUE
rb_arg_error_new(int argc, int min, int max)
{
    VALUE err_mess = 0;
    if (min == max) {
        err_mess = rb_sprintf("wrong number of arguments (%d for %d)", argc, min);
    }
    else if (max == UNLIMITED_ARGUMENTS) {
        err_mess = rb_sprintf("wrong number of arguments (%d for %d+)", argc, min);
    }
    else {
        err_mess = rb_sprintf("wrong number of arguments (%d for %d..%d)", argc, min, max);
    }
    return rb_exc_new3(rb_eArgError, err_mess);
}

NORETURN(static void argument_error(const rb_iseq_t *iseq, int miss_argc, int min_argc, int max_argc));
static void
argument_error(const rb_iseq_t *iseq, int miss_argc, int min_argc, int max_argc)
{
    rb_thread_t *th = GET_THREAD();
    VALUE exc = rb_arg_error_new(miss_argc, min_argc, max_argc);
    VALUE at;

    if (iseq) {
        vm_push_frame(th, iseq, VM_FRAME_MAGIC_METHOD, Qnil /* self */, Qnil /* klass */, Qnil /* specval*/,
                      iseq->iseq_encoded, th->cfp->sp, 0 /* local_size */, 0 /* me */, 0 /* stack_max */);
        at = rb_vm_backtrace_object();
        vm_pop_frame(th);
    }
    else {
        at = rb_vm_backtrace_object();
    }

    rb_iv_set(exc, "bt_locations", at);
    rb_funcall(exc, rb_intern("set_backtrace"), 1, at);
    rb_exc_raise(exc);
}

void
rb_error_arity(int argc, int min, int max)
{
    rb_exc_raise(rb_arg_error_new(argc, min, max));
}

/* svar */

static inline NODE *
lep_svar_place(rb_thread_t *th, VALUE *lep)
{
    VALUE *svar;

    if (lep && th->root_lep != lep) {
        svar = &lep[-1];
    }
    else {
        svar = &th->root_svar;
    }
    if (NIL_P(*svar)) {
        *svar = (VALUE)NEW_IF(Qnil, Qnil, Qnil);
    }
    return (NODE *)*svar;
}

static VALUE
lep_svar_get(rb_thread_t *th, VALUE *lep, rb_num_t key)
{
    NODE *svar = lep_svar_place(th, lep);

    switch (key) {
      case 0:
        return svar->u1.value;
      case 1:
        return svar->u2.value;
      default: {
        const VALUE ary = svar->u3.value;

        if (NIL_P(ary)) {
            return Qnil;
        }
        else {
            return rb_ary_entry(ary, key - DEFAULT_SPECIAL_VAR_COUNT);
        }
      }
    }
}

static void
lep_svar_set(rb_thread_t *th, VALUE *lep, rb_num_t key, VALUE val)
{
    NODE *svar = lep_svar_place(th, lep);

    switch (key) {
      case 0:
        svar->u1.value = val;
        return;
      case 1:
        svar->u2.value = val;
        return;
      default: {
        VALUE ary = svar->u3.value;

        if (NIL_P(ary)) {
            svar->u3.value = ary = rb_ary_new();
        }
        rb_ary_store(ary, key - DEFAULT_SPECIAL_VAR_COUNT, val);
      }
    }
}

static inline VALUE
vm_getspecial(rb_thread_t *th, VALUE *lep, rb_num_t key, rb_num_t type)
{
    VALUE val;

    if (type == 0) {
        val = lep_svar_get(th, lep, key);
    }
    else {
        VALUE backref = lep_svar_get(th, lep, 1);

        if (type & 0x01) {
            switch (type >> 1) {
              case '&':
                val = rb_reg_last_match(backref);
                break;
              case '`':
                val = rb_reg_match_pre(backref);
                break;
              case '\'':
                val = rb_reg_match_post(backref);
                break;
              case '+':
                val = rb_reg_match_last(backref);
                break;
              default:
                rb_bug("unexpected back-ref");
            }
        }
        else {
            val = rb_reg_nth_match((int)(type >> 1), backref);
        }
    }
    return val;
}

static NODE *
vm_get_cref0(const rb_iseq_t *iseq, const VALUE *ep)
{
    while (1) {
        if (VM_EP_LEP_P(ep)) {
            if (!RUBY_VM_NORMAL_ISEQ_P(iseq)) return NULL;
            return iseq->cref_stack;
        }
        else if (ep[-1] != Qnil) {
            return (NODE *)ep[-1];
        }
        ep = VM_EP_PREV_EP(ep);
    }
}

NODE *
rb_vm_get_cref(const rb_iseq_t *iseq, const VALUE *ep)
{
    NODE *cref = vm_get_cref0(iseq, ep);

    if (cref == 0) {
        rb_bug("rb_vm_get_cref: unreachable");
    }
    return cref;
}

static NODE *
vm_cref_push(rb_thread_t *th, VALUE klass, int noex, rb_block_t *blockptr)
{
    rb_control_frame_t *cfp = vm_get_ruby_level_caller_cfp(th, th->cfp);
    NODE *cref = NEW_CREF(klass);
    cref->nd_refinements = Qnil;
    cref->nd_visi = noex;

    if (blockptr) {
        RB_OBJ_WRITE(cref, &cref->nd_next, vm_get_cref0(blockptr->iseq, blockptr->ep));
    }
    else if (cfp) {
        RB_OBJ_WRITE(cref, &cref->nd_next, vm_get_cref0(cfp->iseq, cfp->ep));
    }
    /* TODO: why cref->nd_next is 1? */
    if (cref->nd_next && cref->nd_next != (void *) 1 &&
        !NIL_P(cref->nd_next->nd_refinements)) {
        COPY_CREF_OMOD(cref, cref->nd_next);
    }

    return cref;
}

static inline VALUE
vm_get_cbase(const rb_iseq_t *iseq, const VALUE *ep)
{
    NODE *cref = rb_vm_get_cref(iseq, ep);
    VALUE klass = Qundef;

    while (cref) {
        if ((klass = cref->nd_clss) != 0) {
            break;
        }
        cref = cref->nd_next;
    }

    return klass;
}

static inline VALUE
vm_get_const_base(const rb_iseq_t *iseq, const VALUE *ep)
{
    NODE *cref = rb_vm_get_cref(iseq, ep);
    VALUE klass = Qundef;

    while (cref) {
        if (!(cref->flags & NODE_FL_CREF_PUSHED_BY_EVAL) &&
            (klass = cref->nd_clss) != 0) {
            break;
        }
        cref = cref->nd_next;
    }

    return klass;
}

static inline void
vm_check_if_namespace(VALUE klass)
{
    VALUE str;
    if (!RB_TYPE_P(klass, T_CLASS) && !RB_TYPE_P(klass, T_MODULE)) {
        str = rb_inspect(klass);
        rb_raise(rb_eTypeError, "%s is not a class/module",
                 StringValuePtr(str));
    }
}

static inline VALUE
vm_get_iclass(rb_control_frame_t *cfp, VALUE klass)
{
    if (RB_TYPE_P(klass, T_MODULE) &&
        FL_TEST(klass, RMODULE_IS_OVERLAID) &&
        RB_TYPE_P(cfp->klass, T_ICLASS) &&
        RBASIC(cfp->klass)->klass == klass) {
        return cfp->klass;
    }
    else {
        return klass;
    }
}

static inline VALUE
vm_get_ev_const(rb_thread_t *th, const rb_iseq_t *iseq,
                VALUE orig_klass, ID id, int is_defined)
{
    VALUE val;

    if (orig_klass == Qnil) {
        /* in current lexical scope */
        const NODE *root_cref = rb_vm_get_cref(iseq, th->cfp->ep);
        const NODE *cref;
        VALUE klass = orig_klass;

        while (root_cref && root_cref->flags & NODE_FL_CREF_PUSHED_BY_EVAL) {
            root_cref = root_cref->nd_next;
        }
        cref = root_cref;
        while (cref && cref->nd_next) {
            if (cref->flags & NODE_FL_CREF_PUSHED_BY_EVAL) {
                klass = Qnil;
            }
            else {
                klass = cref->nd_clss;
            }
            cref = cref->nd_next;

            if (!NIL_P(klass)) {
                VALUE av, am = 0;
                st_data_t data;
              search_continue:
                if (RCLASS_CONST_TBL(klass) &&
                    st_lookup(RCLASS_CONST_TBL(klass), id, &data)) {
                    val = ((rb_const_entry_t*)data)->value;
                    if (val == Qundef) {
                        if (am == klass) break;
                        am = klass;
                        if (is_defined) return 1;
                        if (rb_autoloading_value(klass, id, &av)) return av;
                        rb_autoload_load(klass, id);
                        goto search_continue;
                    }
                    else {
                        if (is_defined) {
                            return 1;
                        }
                        else {
                            return val;
                        }
                    }
                }
            }
        }

        /* search self */
        if (root_cref && !NIL_P(root_cref->nd_clss)) {
            klass = vm_get_iclass(th->cfp, root_cref->nd_clss);
        }
        else {
            klass = CLASS_OF(th->cfp->self);
        }

        if (is_defined) {
            return rb_const_defined(klass, id);
        }
        else {
            return rb_const_get(klass, id);
        }
    }
    else {
        vm_check_if_namespace(orig_klass);
        if (is_defined) {
            return rb_public_const_defined_from(orig_klass, id);
        }
        else {
            return rb_public_const_get_from(orig_klass, id);
        }
    }
}

static inline VALUE
vm_get_cvar_base(NODE *cref, rb_control_frame_t *cfp)
{
    VALUE klass;

    if (!cref) {
        rb_bug("vm_get_cvar_base: no cref");
    }

    while (cref->nd_next &&
           (NIL_P(cref->nd_clss) || FL_TEST(cref->nd_clss, FL_SINGLETON) ||
            (cref->flags & NODE_FL_CREF_PUSHED_BY_EVAL))) {
        cref = cref->nd_next;
    }
    if (!cref->nd_next) {
        rb_warn("class variable access from toplevel");
    }

    klass = vm_get_iclass(cfp, cref->nd_clss);

    if (NIL_P(klass)) {
        rb_raise(rb_eTypeError, "no class variables available");
    }
    return klass;
}

static VALUE
vm_search_const_defined_class(const VALUE cbase, ID id)
{
    if (rb_const_defined_at(cbase, id)) return cbase;
    if (cbase == rb_cObject) {
        VALUE tmp = RCLASS_SUPER(cbase);
        while (tmp) {
            if (rb_const_defined_at(tmp, id)) return tmp;
            tmp = RCLASS_SUPER(tmp);
        }
    }
    return 0;
}

#ifndef USE_IC_FOR_IVAR
#define USE_IC_FOR_IVAR 1
#endif

static inline VALUE
vm_getivar(VALUE obj, ID id, IC ic, rb_call_info_t *ci, int is_attr)
{
#if USE_IC_FOR_IVAR
    if (RB_TYPE_P(obj, T_OBJECT)) {
        VALUE val = Qundef;
        VALUE klass = RBASIC(obj)->klass;

        if (LIKELY((!is_attr && ic->ic_serial == RCLASS_SERIAL(klass)) ||
                   (is_attr && ci->aux.index > 0))) {
            long index = !is_attr ? (long)ic->ic_value.index : ci->aux.index - 1;
            long len = ROBJECT_NUMIV(obj);
            VALUE *ptr = ROBJECT_IVPTR(obj);

            if (index < len) {
                val = ptr[index];
            }
        }
        else {
            st_data_t index;
            long len = ROBJECT_NUMIV(obj);
            VALUE *ptr = ROBJECT_IVPTR(obj);
            struct st_table *iv_index_tbl = ROBJECT_IV_INDEX_TBL(obj);

            if (iv_index_tbl) {
                if (st_lookup(iv_index_tbl, id, &index)) {
                    if ((long)index < len) {
                        val = ptr[index];
                    }
                    if (!is_attr) {
                        ic->ic_value.index = index;
                        ic->ic_serial = RCLASS_SERIAL(klass);
                    }
                    else { /* call_info */
                        ci->aux.index = index + 1;
                    }
                }
            }
        }

        if (UNLIKELY(val == Qundef)) {
            if (!is_attr) rb_warning("instance variable %s not initialized", rb_id2name(id));
            val = Qnil;
        }
        return val;
    }
#endif  /* USE_IC_FOR_IVAR */
    if (is_attr)
        return rb_attr_get(obj, id);
    return rb_ivar_get(obj, id);
}

static inline VALUE
vm_setivar(VALUE obj, ID id, VALUE val, IC ic, rb_call_info_t *ci, int is_attr)
{
#if USE_IC_FOR_IVAR
    rb_check_frozen(obj);

    if (RB_TYPE_P(obj, T_OBJECT)) {
        VALUE klass = RBASIC(obj)->klass;
        st_data_t index;

        if (LIKELY(
            (!is_attr && ic->ic_serial == RCLASS_SERIAL(klass)) ||
            (is_attr && ci->aux.index > 0))) {
            long index = !is_attr ? (long)ic->ic_value.index : ci->aux.index-1;
            long len = ROBJECT_NUMIV(obj);
            VALUE *ptr = ROBJECT_IVPTR(obj);

            if (index < len) {
                RB_OBJ_WRITE(obj, &ptr[index], val);
                return val; /* inline cache hit */
            }
        }
        else {
            struct st_table *iv_index_tbl = ROBJECT_IV_INDEX_TBL(obj);

            if (iv_index_tbl && st_lookup(iv_index_tbl, (st_data_t)id, &index)) {
                if (!is_attr) {
                    ic->ic_value.index = index;
                    ic->ic_serial = RCLASS_SERIAL(klass);
                }
                else {
                    ci->aux.index = index + 1;
                }
            }
            /* fall through */
        }
    }
#endif  /* USE_IC_FOR_IVAR */
    return rb_ivar_set(obj, id, val);
}

static VALUE
vm_getinstancevariable(VALUE obj, ID id, IC ic)
{
    return vm_getivar(obj, id, ic, 0, 0);
}

static void
vm_setinstancevariable(VALUE obj, ID id, VALUE val, IC ic)
{
    vm_setivar(obj, id, val, ic, 0, 0);
}

static VALUE
vm_throw(rb_thread_t *th, rb_control_frame_t *reg_cfp,
         rb_num_t throw_state, VALUE throwobj)
{
    int state = (int)(throw_state & 0xff);
    int flag = (int)(throw_state & 0x8000);
    rb_num_t level = throw_state >> 16;

    if (state != 0) {
        VALUE *pt = 0;
        if (flag != 0) {
            pt = (void *) 1;
        }
        else {
            if (state == TAG_BREAK) {
                rb_control_frame_t *cfp = GET_CFP();
                VALUE *ep = GET_EP();
                int is_orphan = 1;
                rb_iseq_t *base_iseq = GET_ISEQ();

              search_parent:
                if (cfp->iseq->type != ISEQ_TYPE_BLOCK) {
                    if (cfp->iseq->type == ISEQ_TYPE_CLASS) {
                        cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
                        ep = cfp->ep;
                        goto search_parent;
                    }
                    ep = VM_EP_PREV_EP(ep);
                    base_iseq = base_iseq->parent_iseq;

                    while ((VALUE *) cfp < th->stack + th->stack_size) {
                        if (cfp->ep == ep) {
                            goto search_parent;
                        }
                        cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
                    }
                    rb_bug("VM (throw): can't find break base.");
                }

                if (VM_FRAME_TYPE(cfp) == VM_FRAME_MAGIC_LAMBDA) {
                    /* lambda{... break ...} */
                    is_orphan = 0;
                    pt = cfp->ep;
                    state = TAG_RETURN;
                }
                else {
                    ep = VM_EP_PREV_EP(ep);

                    while ((VALUE *)cfp < th->stack + th->stack_size) {
                        if (cfp->ep == ep) {
                            VALUE epc = cfp->pc - cfp->iseq->iseq_encoded;
                            rb_iseq_t *iseq = cfp->iseq;
                            int i;

                            for (i=0; i<iseq->catch_table_size; i++) {
                                struct iseq_catch_table_entry *entry = &iseq->catch_table[i];

                                if (entry->type == CATCH_TYPE_BREAK &&
                                    entry->start < epc && entry->end >= epc) {
                                    if (entry->cont == epc) {
                                        goto found;
                                    }
                                    else {
                                        break;
                                    }
                                }
                            }
                            break;

                          found:
                            pt = ep;
                            is_orphan = 0;
                            break;
                        }
                        cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
                    }
                }

                if (is_orphan) {
                    rb_vm_localjump_error("break from proc-closure", throwobj, TAG_BREAK);
                }
            }
            else if (state == TAG_RETRY) {
                rb_num_t i;
                pt = VM_EP_PREV_EP(GET_EP());
                for (i = 0; i < level; i++) {
                    pt = GC_GUARDED_PTR_REF((VALUE *) * pt);
                }
            }
            else if (state == TAG_RETURN) {
                rb_control_frame_t *cfp = GET_CFP();
                VALUE *ep = GET_EP();
                VALUE *target_lep = VM_CF_LEP(cfp);
                int in_class_frame = 0;

                /* check orphan and get dfp */
                while ((VALUE *) cfp < th->stack + th->stack_size) {
                    VALUE *lep = VM_CF_LEP(cfp);

                    if (!target_lep) {
                        target_lep = lep;
                    }

                    if (lep == target_lep && cfp->iseq->type == ISEQ_TYPE_CLASS) {
                        in_class_frame = 1;
                        target_lep = 0;
                    }

                    if (lep == target_lep) {
                        if (VM_FRAME_TYPE(cfp) == VM_FRAME_MAGIC_LAMBDA) {
                            VALUE *tep = ep;

                            if (in_class_frame) {
                                /* lambda {class A; ... return ...; end} */
                                ep = cfp->ep;
                                goto valid_return;
                            }

                            while (target_lep != tep) {
                                if (cfp->ep == tep) {
                                    /* in lambda */
                                    ep = cfp->ep;
                                    goto valid_return;
                                }
                                tep = VM_EP_PREV_EP(tep);
                            }
                        }
                    }

                    if (cfp->ep == target_lep && cfp->iseq->type == ISEQ_TYPE_METHOD) {
                        ep = target_lep;
                        goto valid_return;
                    }

                    cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
                }

                rb_vm_localjump_error("unexpected return", throwobj, TAG_RETURN);

              valid_return:
                pt = ep;
            }
            else {
                rb_bug("isns(throw): unsupport throw type");
            }
        }
        th->state = state;
        return (VALUE)NEW_THROW_OBJECT(throwobj, (VALUE) pt, state);
    }
    else {
        /* continue throw */
        VALUE err = throwobj;

        if (FIXNUM_P(err)) {
            th->state = FIX2INT(err);
        }
        else if (SYMBOL_P(err)) {
            th->state = TAG_THROW;
        }
        else if (BUILTIN_TYPE(err) == T_NODE) {
            th->state = GET_THROWOBJ_STATE(err);
        }
        else {
            th->state = TAG_RAISE;
            /*th->state = FIX2INT(rb_ivar_get(err, idThrowState));*/
        }
        return err;
    }
}

static inline void
vm_expandarray(rb_control_frame_t *cfp, VALUE ary, rb_num_t num, int flag)
{
    int is_splat = flag & 0x01;
    rb_num_t space_size = num + is_splat;
    VALUE *base = cfp->sp;
    const VALUE *ptr;
    rb_num_t len;

    if (!RB_TYPE_P(ary, T_ARRAY)) {
        ary = rb_ary_to_ary(ary);
    }

    cfp->sp += space_size;

    ptr = RARRAY_CONST_PTR(ary);
    len = (rb_num_t)RARRAY_LEN(ary);

    if (flag & 0x02) {
        /* post: ..., nil ,ary[-1], ..., ary[0..-num] # top */
        rb_num_t i = 0, j;

        if (len < num) {
            for (i=0; i<num-len; i++) {
                *base++ = Qnil;
            }
        }
        for (j=0; i<num; i++, j++) {
            VALUE v = ptr[len - j - 1];
            *base++ = v;
        }
        if (is_splat) {
            *base = rb_ary_new4(len - j, ptr);
        }
    }
    else {
        /* normal: ary[num..-1], ary[num-2], ary[num-3], ..., ary[0] # top */
        rb_num_t i;
        VALUE *bptr = &base[space_size - 1];

        for (i=0; i<num; i++) {
            if (len <= i) {
                for (; i<num; i++) {
                    *bptr-- = Qnil;
                }
                break;
            }
            *bptr-- = ptr[i];
        }
        if (is_splat) {
            if (num > len) {
                *bptr = rb_ary_new();
            }
            else {
                *bptr = rb_ary_new4(len - num, ptr + num);
            }
        }
    }
    RB_GC_GUARD(ary);
}

static VALUE vm_call_general(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci);

static void
vm_search_method(rb_call_info_t *ci, VALUE recv)
{
    VALUE klass = CLASS_OF(recv);

#if OPT_INLINE_METHOD_CACHE
    if (LIKELY(GET_GLOBAL_METHOD_STATE() == ci->method_state && RCLASS_SERIAL(klass) == ci->class_serial)) {
        /* cache hit! */
        return;
    }
#endif

    ci->me = rb_method_entry(klass, ci->mid, &ci->defined_class);
    ci->klass = klass;
    ci->call = vm_call_general;
#if OPT_INLINE_METHOD_CACHE
    ci->method_state = GET_GLOBAL_METHOD_STATE();
    ci->class_serial = RCLASS_SERIAL(klass);
#endif
}

static inline int
check_cfunc(const rb_method_entry_t *me, VALUE (*func)())
{
    if (me && me->def->type == VM_METHOD_TYPE_CFUNC &&
        me->def->body.cfunc.func == func) {
        return 1;
    }
    else {
        return 0;
    }
}

static
#ifndef NO_BIG_INLINE
inline
#endif
VALUE
opt_eq_func(VALUE recv, VALUE obj, CALL_INFO ci)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_EQ, FIXNUM_REDEFINED_OP_FLAG)) {
        return (recv == obj) ? Qtrue : Qfalse;
    }
    else if (FLONUM_2_P(recv, obj) &&
             BASIC_OP_UNREDEFINED_P(BOP_EQ, FLOAT_REDEFINED_OP_FLAG)) {
        return (recv == obj) ? Qtrue : Qfalse;
    }
    else if (!SPECIAL_CONST_P(recv) && !SPECIAL_CONST_P(obj)) {
        if (RBASIC_CLASS(recv) == rb_cFloat &&
            RBASIC_CLASS(obj) == rb_cFloat &&
            BASIC_OP_UNREDEFINED_P(BOP_EQ, FLOAT_REDEFINED_OP_FLAG)) {
            double a = RFLOAT_VALUE(recv);
            double b = RFLOAT_VALUE(obj);

            if (isnan(a) || isnan(b)) {
                return Qfalse;
            }
            return  (a == b) ? Qtrue : Qfalse;
        }
        else if (RBASIC_CLASS(recv) == rb_cString &&
                 RBASIC_CLASS(obj) == rb_cString &&
                 BASIC_OP_UNREDEFINED_P(BOP_EQ, STRING_REDEFINED_OP_FLAG)) {
            return rb_str_equal(recv, obj);
        }
    }

    {
        vm_search_method(ci, recv);

        if (check_cfunc(ci->me, rb_obj_equal)) {
            return recv == obj ? Qtrue : Qfalse;
        }
    }

    return Qundef;
}

VALUE
rb_equal_opt(VALUE obj1, VALUE obj2)
{
    rb_call_info_t ci;
    ci.mid = idEq;
    ci.klass = 0;
    ci.method_state = 0;
    ci.me = NULL;
    ci.defined_class = 0;
    return opt_eq_func(obj1, obj2, &ci);
}

static VALUE
vm_call0(rb_thread_t*, VALUE, ID, int, const VALUE*, const rb_method_entry_t*, VALUE);

static VALUE
check_match(VALUE pattern, VALUE target, enum vm_check_match_type type)
{
    switch (type) {
      case VM_CHECKMATCH_TYPE_WHEN:
        return pattern;
      case VM_CHECKMATCH_TYPE_RESCUE:
        if (!rb_obj_is_kind_of(pattern, rb_cModule)) {
            rb_raise(rb_eTypeError, "class or module required for rescue clause");
        }
        /* fall through */
      case VM_CHECKMATCH_TYPE_CASE: {
        VALUE defined_class;
        rb_method_entry_t *me = rb_method_entry_with_refinements(CLASS_OF(pattern), idEqq, &defined_class);
        if (me) {
          return vm_call0(GET_THREAD(), pattern, idEqq, 1, &target, me, defined_class);
        }
        else {
          /* fallback to funcall (e.g. method_missing) */
          return rb_funcall2(pattern, idEqq, 1, &target);
        }
      }
      default:
        rb_bug("check_match: unreachable");
    }
}


#if defined(_MSC_VER) && _MSC_VER < 1300
#define CHECK_CMP_NAN(a, b) if (isnan(a) || isnan(b)) return Qfalse;
#else
#define CHECK_CMP_NAN(a, b) /* do nothing */
#endif

static inline VALUE
double_cmp_lt(double a, double b)
{
    CHECK_CMP_NAN(a, b);
    return a < b ? Qtrue : Qfalse;
}

static inline VALUE
double_cmp_le(double a, double b)
{
    CHECK_CMP_NAN(a, b);
    return a <= b ? Qtrue : Qfalse;
}

static inline VALUE
double_cmp_gt(double a, double b)
{
    CHECK_CMP_NAN(a, b);
    return a > b ? Qtrue : Qfalse;
}

static inline VALUE
double_cmp_ge(double a, double b)
{
    CHECK_CMP_NAN(a, b);
    return a >= b ? Qtrue : Qfalse;
}

static VALUE *
vm_base_ptr(rb_control_frame_t *cfp)
{
    rb_control_frame_t *prev_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
    VALUE *bp = prev_cfp->sp + cfp->iseq->local_size + 1;

    if (cfp->iseq->type == ISEQ_TYPE_METHOD) {
        /* adjust `self' */
        bp += 1;
    }

#if VM_DEBUG_BP_CHECK
    if (bp != cfp->bp_check) {
        fprintf(stderr, "bp_check: %ld, bp: %ld\n",
                (long)(cfp->bp_check - GET_THREAD()->stack),
                (long)(bp - GET_THREAD()->stack));
        rb_bug("vm_base_ptr: unreachable");
    }
#endif

    return bp;
}

/* method call processes with call_info */

static void
vm_caller_setup_args(const rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
{
#define SAVE_RESTORE_CI(expr, ci) do { \
    int saved_argc = (ci)->argc; rb_block_t *saved_blockptr = (ci)->blockptr; /* save */ \
    expr; \
    (ci)->argc = saved_argc; (ci)->blockptr = saved_blockptr; /* restore */ \
} while (0)

    if (UNLIKELY(ci->flag & VM_CALL_ARGS_BLOCKARG)) {
        rb_proc_t *po;
        VALUE proc;

        proc = *(--cfp->sp);

        if (proc != Qnil) {
            if (!rb_obj_is_proc(proc)) {
                VALUE b;

                SAVE_RESTORE_CI(b = rb_check_convert_type(proc, T_DATA, "Proc", "to_proc"), ci);

                if (NIL_P(b) || !rb_obj_is_proc(b)) {
                    rb_raise(rb_eTypeError,
                             "wrong argument type %s (expected Proc)",
                             rb_obj_classname(proc));
                }
                proc = b;
            }
            GetProcPtr(proc, po);
            ci->blockptr = &po->block;
            RUBY_VM_GET_BLOCK_PTR_IN_CFP(cfp)->proc = proc;
        }
    }
    else if (ci->blockiseq != 0) { /* likely */
        ci->blockptr = RUBY_VM_GET_BLOCK_PTR_IN_CFP(cfp);
        ci->blockptr->iseq = ci->blockiseq;
        ci->blockptr->proc = 0;
    }

    /* expand top of stack? */

    if (UNLIKELY(ci->flag & VM_CALL_ARGS_SPLAT)) {
        VALUE ary = *(cfp->sp - 1);
        const VALUE *ptr;
        int i;
        VALUE tmp;

        SAVE_RESTORE_CI(tmp = rb_check_convert_type(ary, T_ARRAY, "Array", "to_a"), ci);

        if (NIL_P(tmp)) {
            /* do nothing */
        }
        else {
            long len = RARRAY_LEN(tmp);
            ptr = RARRAY_CONST_PTR(tmp);
            cfp->sp -= 1;

            CHECK_VM_STACK_OVERFLOW(cfp, len);

            for (i = 0; i < len; i++) {
                *cfp->sp++ = ptr[i];
            }
            ci->argc += i-1;
        }
    }
}

static inline int
vm_callee_setup_keyword_arg(rb_thread_t *th, const rb_iseq_t *iseq, int argc, int m, VALUE *orig_argv, VALUE *kwd)
{
    VALUE keyword_hash = 0, orig_hash;
    int optional = iseq->arg_keywords - iseq->arg_keyword_required;
    VALUE *const sp = th->cfp->sp;
    const int mark_stack_len = th->mark_stack_len;

    th->cfp->sp += argc;
    th->mark_stack_len -= argc;

    if (argc > m &&
        !NIL_P(orig_hash = rb_check_hash_type(orig_argv[argc-1])) &&
        (keyword_hash = rb_extract_keywords(&orig_hash)) != 0) {
        if (!orig_hash) {
            argc--;
        }
        else {
            orig_argv[argc-1] = orig_hash;
        }
    }
    rb_get_kwargs(keyword_hash, iseq->arg_keyword_table, iseq->arg_keyword_required,
                  (iseq->arg_keyword_check ? optional : -1-optional),
                  NULL);

    if (!keyword_hash) {
        keyword_hash = rb_hash_new();
    }

    th->cfp->sp = sp;
    th->mark_stack_len = mark_stack_len;

    *kwd = keyword_hash;

    return argc;
}

static inline int
vm_callee_setup_arg_complex(rb_thread_t *th, rb_call_info_t *ci, const rb_iseq_t *iseq, VALUE *orig_argv)
{
    const int m = iseq->argc;
    const int opts = iseq->arg_opts - (iseq->arg_opts > 0);
    const int min = m + iseq->arg_post_len;
    const int max = (iseq->arg_rest == -1) ? m + opts + iseq->arg_post_len : UNLIMITED_ARGUMENTS;
    const int orig_argc = ci->argc;
    int argc = orig_argc;
    VALUE *argv = orig_argv;
    VALUE keyword_hash = Qnil;
    rb_num_t opt_pc = 0;

    th->mark_stack_len = argc + iseq->arg_size;

    /* keyword argument */
    if (iseq->arg_keyword != -1) {
        argc = vm_callee_setup_keyword_arg(th, iseq, argc, min, orig_argv, &keyword_hash);
    }

    /* mandatory */
    if ((argc < min) || (argc > max && max != UNLIMITED_ARGUMENTS)) {
        argument_error(iseq, argc, min, max);
    }

    argv += m;
    argc -= m;

    /* post arguments */
    if (iseq->arg_post_len) {
        if (!(orig_argc < iseq->arg_post_start)) {
            VALUE *new_argv = ALLOCA_N(VALUE, argc);
            MEMCPY(new_argv, argv, VALUE, argc);
            argv = new_argv;
        }

        MEMCPY(&orig_argv[iseq->arg_post_start], &argv[argc -= iseq->arg_post_len],
               VALUE, iseq->arg_post_len);
    }

    /* opt arguments */
    if (iseq->arg_opts) {
        if (argc > opts) {
            argc -= opts;
            argv += opts;
            opt_pc = iseq->arg_opt_table[opts]; /* no opt */
        }
        else {
            int i;
            for (i = argc; i<opts; i++) {
                orig_argv[i + m] = Qnil;
            }
            opt_pc = iseq->arg_opt_table[argc];
            argc = 0;
        }
    }

    /* rest arguments */
    if (iseq->arg_rest != -1) {
        orig_argv[iseq->arg_rest] = rb_ary_new4(argc, argv);
        argc = 0;
    }

    /* keyword argument */
    if (iseq->arg_keyword != -1) {
        int i;
        int arg_keywords_end = iseq->arg_keyword - (iseq->arg_block != -1);
        for (i = iseq->arg_keywords; 0 < i; i--) {
            orig_argv[arg_keywords_end - i] = Qnil;
        }
        orig_argv[iseq->arg_keyword] = keyword_hash;
    }

    /* block arguments */
    if (iseq->arg_block != -1) {
        VALUE blockval = Qnil;
        const rb_block_t *blockptr = ci->blockptr;

        if (blockptr) {
            /* make Proc object */
            if (blockptr->proc == 0) {
                rb_proc_t *proc;
                blockval = rb_vm_make_proc(th, blockptr, rb_cProc);
                GetProcPtr(blockval, proc);
                ci->blockptr = &proc->block;
            }
            else {
                blockval = blockptr->proc;
            }
        }

        orig_argv[iseq->arg_block] = blockval; /* Proc or nil */
    }

    th->mark_stack_len = 0;
    return (int)opt_pc;
}

static VALUE vm_call_iseq_setup_2(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);
static inline VALUE vm_call_iseq_setup_normal(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);
static inline VALUE vm_call_iseq_setup_tailcall(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);

static inline void
vm_callee_setup_arg(rb_thread_t *th, rb_call_info_t *ci, const rb_iseq_t *iseq,
                    VALUE *argv, int is_lambda)
{
    if (LIKELY(iseq->arg_simple & 0x01)) {
        /* simple check */
        if (ci->argc != iseq->argc) {
            argument_error(iseq, ci->argc, iseq->argc, iseq->argc);
        }
        ci->aux.opt_pc = 0;
        CI_SET_FASTPATH(ci,
                        (UNLIKELY(ci->flag & VM_CALL_TAILCALL) ?
                         vm_call_iseq_setup_tailcall :
                         vm_call_iseq_setup_normal),
                        (!is_lambda &&
                         !(ci->flag & VM_CALL_ARGS_SPLAT) && /* argc may differ for each calls */
                         !(ci->me->flag & NOEX_PROTECTED)));
    }
    else {
        ci->aux.opt_pc = vm_callee_setup_arg_complex(th, ci, iseq, argv);
    }
}

static VALUE
vm_call_iseq_setup(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
{
    vm_callee_setup_arg(th, ci, ci->me->def->body.iseq, cfp->sp - ci->argc, 0);
    return vm_call_iseq_setup_2(th, cfp, ci);
}

static VALUE
vm_call_iseq_setup_2(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
{
    if (LIKELY(!(ci->flag & VM_CALL_TAILCALL))) {
        return vm_call_iseq_setup_normal(th, cfp, ci);
    }
    else {
        return vm_call_iseq_setup_tailcall(th, cfp, ci);
    }
}

static inline VALUE
vm_call_iseq_setup_normal(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
{
    int i, local_size;
    VALUE *argv = cfp->sp - ci->argc;
    rb_iseq_t *iseq = ci->me->def->body.iseq;
    VALUE *sp = argv + iseq->arg_size;

    /* clear local variables (arg_size...local_size) */
    for (i = iseq->arg_size, local_size = iseq->local_size; i < local_size; i++) {
        *sp++ = Qnil;
    }

    vm_push_frame(th, iseq, VM_FRAME_MAGIC_METHOD, ci->recv, ci->defined_class,
                  VM_ENVVAL_BLOCK_PTR(ci->blockptr),
                  iseq->iseq_encoded + ci->aux.opt_pc, sp, 0, ci->me, iseq->stack_max);

    cfp->sp = argv - 1 /* recv */;
    return Qundef;
}

static inline VALUE
vm_call_iseq_setup_tailcall(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
{
    int i;
    VALUE *argv = cfp->sp - ci->argc;
    rb_iseq_t *iseq = ci->me->def->body.iseq;
    VALUE *src_argv = argv;
    VALUE *sp_orig, *sp;
    VALUE finish_flag = VM_FRAME_TYPE_FINISH_P(cfp) ? VM_FRAME_FLAG_FINISH : 0;

    cfp = th->cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(th->cfp); /* pop cf */

    RUBY_VM_CHECK_INTS(th);

    sp_orig = sp = cfp->sp;

    /* push self */
    sp[0] = ci->recv;
    sp++;

    /* copy arguments */
    for (i=0; i < iseq->arg_size; i++) {
        *sp++ = src_argv[i];
    }

    /* clear local variables */
    for (i = 0; i < iseq->local_size - iseq->arg_size; i++) {
        *sp++ = Qnil;
    }

    vm_push_frame(th, iseq, VM_FRAME_MAGIC_METHOD | finish_flag,
                  ci->recv, ci->defined_class, VM_ENVVAL_BLOCK_PTR(ci->blockptr),
                  iseq->iseq_encoded + ci->aux.opt_pc, sp, 0, ci->me, iseq->stack_max);

    cfp->sp = sp_orig;
    return Qundef;
}

static VALUE
call_cfunc_m2(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, rb_ary_new4(argc, argv));
}

static VALUE
call_cfunc_m1(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(argc, argv, recv);
}

static VALUE
call_cfunc_0(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv);
}

static VALUE
call_cfunc_1(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0]);
}

static VALUE
call_cfunc_2(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1]);
}

static VALUE
call_cfunc_3(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2]);
}

static VALUE
call_cfunc_4(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3]);
}

static VALUE
call_cfunc_5(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4]);
}

static VALUE
call_cfunc_6(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5]);
}

static VALUE
call_cfunc_7(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6]);
}

static VALUE
call_cfunc_8(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7]);
}

static VALUE
call_cfunc_9(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8]);
}

static VALUE
call_cfunc_10(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8], argv[9]);
}

static VALUE
call_cfunc_11(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8], argv[9], argv[10]);
}

static VALUE
call_cfunc_12(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8], argv[9], argv[10], argv[11]);
}

static VALUE
call_cfunc_13(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8], argv[9], argv[10], argv[11], argv[12]);
}

static VALUE
call_cfunc_14(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8], argv[9], argv[10], argv[11], argv[12], argv[13]);
}

static VALUE
call_cfunc_15(VALUE (*func)(ANYARGS), VALUE recv, int argc, const VALUE *argv)
{
    return (*func)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8], argv[9], argv[10], argv[11], argv[12], argv[13], argv[14]);
}

#ifndef VM_PROFILE
#define VM_PROFILE 0
#endif

#if VM_PROFILE
static int vm_profile_counter[4];
#define VM_PROFILE_UP(x) (vm_profile_counter[x]++)
#define VM_PROFILE_ATEXIT() atexit(vm_profile_show_result)
static void
vm_profile_show_result(void)
{
    fprintf(stderr, "VM Profile results: \n");
    fprintf(stderr, "r->c call: %d\n", vm_profile_counter[0]);
    fprintf(stderr, "r->c popf: %d\n", vm_profile_counter[1]);
    fprintf(stderr, "c->c call: %d\n", vm_profile_counter[2]);
    fprintf(stderr, "r->c popf: %d\n", vm_profile_counter[3]);
}
#else
#define VM_PROFILE_UP(x)
#define VM_PROFILE_ATEXIT()
#endif

static inline
const rb_method_cfunc_t *
vm_method_cfunc_entry(const rb_method_entry_t *me)
{
#if VM_DEBUG_VERIFY_METHOD_CACHE
    switch (me->def->type) {
      case VM_METHOD_TYPE_CFUNC:
      case VM_METHOD_TYPE_NOTIMPLEMENTED:
        break;
# define METHOD_BUG(t) case VM_METHOD_TYPE_##t: rb_bug("wrong method type: " #t)
        METHOD_BUG(ISEQ);
        METHOD_BUG(ATTRSET);
        METHOD_BUG(IVAR);
        METHOD_BUG(BMETHOD);
        METHOD_BUG(ZSUPER);
        METHOD_BUG(UNDEF);
        METHOD_BUG(OPTIMIZED);
        METHOD_BUG(MISSING);
        METHOD_BUG(REFINED);
# undef METHOD_BUG
      default:
        rb_bug("wrong method type: %d", me->def->type);
    }
#endif
    return &me->def->body.cfunc;
}

static VALUE
vm_call_cfunc_with_frame(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci)
{
    VALUE val;
    const rb_method_entry_t *me = ci->me;
    const rb_method_cfunc_t *cfunc = vm_method_cfunc_entry(me);
    int len = cfunc->argc;

    /* don't use `ci' after EXEC_EVENT_HOOK because ci can be override */
    VALUE recv = ci->recv;
    VALUE defined_class = ci->defined_class;
    rb_block_t *blockptr = ci->blockptr;
    int argc = ci->argc;

    RUBY_DTRACE_CMETHOD_ENTRY_HOOK(th, me->klass, me->called_id);
    EXEC_EVENT_HOOK(th, RUBY_EVENT_C_CALL, recv, me->called_id, me->klass, Qundef);

    vm_push_frame(th, 0, VM_FRAME_MAGIC_CFUNC, recv, defined_class,
                  VM_ENVVAL_BLOCK_PTR(blockptr), 0, th->cfp->sp, 1, me, 0);

    if (len >= 0) rb_check_arity(argc, len, len);

    reg_cfp->sp -= argc + 1;
    VM_PROFILE_UP(0);
    val = (*cfunc->invoker)(cfunc->func, recv, argc, reg_cfp->sp + 1);

    if (reg_cfp != th->cfp + 1) {
        rb_bug("vm_call_cfunc - cfp consistency error");
    }

    vm_pop_frame(th);

    EXEC_EVENT_HOOK(th, RUBY_EVENT_C_RETURN, recv, me->called_id, me->klass, val);
    RUBY_DTRACE_CMETHOD_RETURN_HOOK(th, me->klass, me->called_id);

    return val;
}

#if OPT_CALL_CFUNC_WITHOUT_FRAME
static VALUE
vm_call_cfunc_latter(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci)
{
    VALUE val;
    int argc = ci->argc;
    VALUE *argv = STACK_ADDR_FROM_TOP(argc);
    const rb_method_cfunc_t *cfunc = vm_method_cfunc_entry(ci->me);

    th->passed_ci = ci;
    reg_cfp->sp -= argc + 1;
    ci->aux.inc_sp = argc + 1;
    VM_PROFILE_UP(0);
    val = (*cfunc->invoker)(cfunc->func, ci, argv);

    /* check */
    if (reg_cfp == th->cfp) { /* no frame push */
        if (UNLIKELY(th->passed_ci != ci)) {
            rb_bug("vm_call_cfunc_latter: passed_ci error (ci: %p, passed_ci: %p)", ci, th->passed_ci);
        }
        th->passed_ci = 0;
    }
    else {
        if (UNLIKELY(reg_cfp != RUBY_VM_PREVIOUS_CONTROL_FRAME(th->cfp))) {
            rb_bug("vm_call_cfunc_latter: cfp consistency error (%p, %p)", reg_cfp, th->cfp+1);
        }
        vm_pop_frame(th);
        VM_PROFILE_UP(1);
    }

    return val;
}

static VALUE
vm_call_cfunc(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci)
{
    VALUE val;
    const rb_method_entry_t *me = ci->me;
    int len = vm_method_cfunc_entry(me)->argc;
    VALUE recv = ci->recv;

    if (len >= 0) rb_check_arity(ci->argc, len, len);

    RUBY_DTRACE_CMETHOD_ENTRY_HOOK(th, me->klass, me->called_id);
    EXEC_EVENT_HOOK(th, RUBY_EVENT_C_CALL, recv, me->called_id, me->klass, Qnil);

    if (!(ci->me->flag & NOEX_PROTECTED) &&
        !(ci->flag & VM_CALL_ARGS_SPLAT)) {
        CI_SET_FASTPATH(ci, vm_call_cfunc_latter, 1);
    }
    val = vm_call_cfunc_latter(th, reg_cfp, ci);

    EXEC_EVENT_HOOK(th, RUBY_EVENT_C_RETURN, recv, me->called_id, me->klass, val);
    RUBY_DTRACE_CMETHOD_RETURN_HOOK(th, me->klass, me->called_id);

    return val;
}

void
vm_call_cfunc_push_frame(rb_thread_t *th)
{
    rb_call_info_t *ci = th->passed_ci;
    const rb_method_entry_t *me = ci->me;
    th->passed_ci = 0;

    vm_push_frame(th, 0, VM_FRAME_MAGIC_CFUNC, ci->recv, ci->defined_class,
                  VM_ENVVAL_BLOCK_PTR(ci->blockptr), 0, th->cfp->sp + ci->aux.inc_sp, 1, me);

    if (ci->call != vm_call_general) {
        ci->call = vm_call_cfunc_with_frame;
    }
}
#else /* OPT_CALL_CFUNC_WITHOUT_FRAME */
static VALUE
vm_call_cfunc(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci)
{
    return vm_call_cfunc_with_frame(th, reg_cfp, ci);
}
#endif

static VALUE
vm_call_ivar(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
{
    VALUE val = vm_getivar(ci->recv, ci->me->def->body.attr.id, 0, ci, 1);
    cfp->sp -= 1;
    return val;
}

static VALUE
vm_call_attrset(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
{
    VALUE val = vm_setivar(ci->recv, ci->me->def->body.attr.id, *(cfp->sp - 1), 0, ci, 1);
    cfp->sp -= 2;
    return val;
}

static inline VALUE
vm_call_bmethod_body(rb_thread_t *th, rb_call_info_t *ci, const VALUE *argv)
{
    rb_proc_t *proc;
    VALUE val;

    /* control block frame */
    th->passed_bmethod_me = ci->me;
    GetProcPtr(ci->me->def->body.proc, proc);
    val = vm_invoke_proc(th, proc, ci->recv, ci->defined_class, ci->argc, argv, ci->blockptr);

    return val;
}

static VALUE
vm_call_bmethod(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
{
    VALUE *argv = ALLOCA_N(VALUE, ci->argc);
    MEMCPY(argv, cfp->sp - ci->argc, VALUE, ci->argc);
    cfp->sp += - ci->argc - 1;

    return vm_call_bmethod_body(th, ci, argv);
}

static
#ifdef _MSC_VER
__forceinline
#else
inline
#endif
VALUE vm_call_method(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci);

static VALUE
vm_call_opt_send(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci)
{
    int i = ci->argc - 1;
    VALUE sym;
    rb_call_info_t ci_entry;

    if (ci->argc == 0) {
        rb_raise(rb_eArgError, "no method name given");
    }

    ci_entry = *ci; /* copy ci entry */
    ci = &ci_entry;

    sym = TOPN(i);

    if (SYMBOL_P(sym)) {
        ci->mid = SYM2ID(sym);
    }
    else if (!(ci->mid = rb_check_id(&sym))) {
        if (rb_method_basic_definition_p(CLASS_OF(ci->recv), idMethodMissing)) {
            VALUE exc = make_no_method_exception(rb_eNoMethodError, NULL, ci->recv, rb_long2int(ci->argc), &TOPN(i));
            rb_exc_raise(exc);
        }
        ci->mid = rb_to_id(sym);
    }

    /* shift arguments */
    if (i > 0) {
        MEMMOVE(&TOPN(i), &TOPN(i-1), VALUE, i);
    }
    ci->me =
        rb_method_entry_without_refinements(CLASS_OF(ci->recv),
                                            ci->mid, &ci->defined_class);
    ci->argc -= 1;
    DEC_SP(1);

    ci->flag = VM_CALL_FCALL | VM_CALL_OPT_SEND;

    return vm_call_method(th, reg_cfp, ci);
}

static VALUE
vm_call_opt_call(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
{
    rb_proc_t *proc;
    int argc = ci->argc;
    VALUE *argv = ALLOCA_N(VALUE, argc);
    GetProcPtr(ci->recv, proc);
    MEMCPY(argv, cfp->sp - argc, VALUE, argc);
    cfp->sp -= argc + 1;

    return rb_vm_invoke_proc(th, proc, argc, argv, ci->blockptr);
}

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);
    rb_call_info_t ci_entry;

    ci_entry.flag = VM_CALL_FCALL | VM_CALL_OPT_SEND;
    ci_entry.argc = ci->argc+1;
    ci_entry.mid = idMethodMissing;
    ci_entry.blockptr = ci->blockptr;
    ci_entry.recv = ci->recv;
    ci_entry.me = rb_method_entry(CLASS_OF(ci_entry.recv), idMethodMissing, &ci_entry.defined_class);

    /* shift arguments: m(a, b, c) #=> method_missing(:m, a, b, c) */
    CHECK_VM_STACK_OVERFLOW(reg_cfp, 1);
    if (ci->argc > 0) {
        MEMMOVE(argv+1, argv, VALUE, ci->argc);
    }
    argv[0] = ID2SYM(ci->mid);
    INC_SP(1);

    th->method_missing_reason = ci->aux.missing_reason;
    return vm_call_method(th, reg_cfp, &ci_entry);
}

static inline VALUE
find_refinement(VALUE refinements, VALUE klass)
{
    if (NIL_P(refinements)) {
        return Qnil;
    }
    return rb_hash_lookup(refinements, klass);
}

static int rb_method_definition_eq(const rb_method_definition_t *d1, const rb_method_definition_t *d2);
static VALUE vm_call_super_method(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci);

static rb_control_frame_t *
current_method_entry(rb_thread_t *th, rb_control_frame_t *cfp)
{
    rb_control_frame_t *top_cfp = cfp;

    if (cfp->iseq && cfp->iseq->type == ISEQ_TYPE_BLOCK) {
        rb_iseq_t *local_iseq = cfp->iseq->local_iseq;
        do {
            cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
            if (RUBY_VM_CONTROL_FRAME_STACK_OVERFLOW_P(th, cfp)) {
                /* TODO: orphan block */
                return top_cfp;
            }
        } while (cfp->iseq != local_iseq);
    }
    return cfp;
}

static
#ifdef _MSC_VER
__forceinline
#else
inline
#endif
VALUE
vm_call_method(rb_thread_t *th, rb_control_frame_t *cfp, rb_call_info_t *ci)
{
    int enable_fastpath = 1;
    rb_call_info_t ci_temp;

  start_method_dispatch:
    if (ci->me != 0) {
        if ((ci->me->flag == 0)) {
            VALUE klass;

          normal_method_dispatch:
            switch (ci->me->def->type) {
              case VM_METHOD_TYPE_ISEQ:{
                CI_SET_FASTPATH(ci, vm_call_iseq_setup, enable_fastpath);
                return vm_call_iseq_setup(th, cfp, ci);
              }
              case VM_METHOD_TYPE_NOTIMPLEMENTED:
              case VM_METHOD_TYPE_CFUNC:
                CI_SET_FASTPATH(ci, vm_call_cfunc, enable_fastpath);
                return vm_call_cfunc(th, cfp, ci);
              case VM_METHOD_TYPE_ATTRSET:{
                rb_check_arity(ci->argc, 1, 1);
                ci->aux.index = 0;
                CI_SET_FASTPATH(ci, vm_call_attrset, enable_fastpath && !(ci->flag & VM_CALL_ARGS_SPLAT));
                return vm_call_attrset(th, cfp, ci);
              }
              case VM_METHOD_TYPE_IVAR:{
                rb_check_arity(ci->argc, 0, 0);
                ci->aux.index = 0;
                CI_SET_FASTPATH(ci, vm_call_ivar, enable_fastpath && !(ci->flag & VM_CALL_ARGS_SPLAT));
                return vm_call_ivar(th, cfp, ci);
              }
              case VM_METHOD_TYPE_MISSING:{
                ci->aux.missing_reason = 0;
                CI_SET_FASTPATH(ci, vm_call_method_missing, enable_fastpath);
                return vm_call_method_missing(th, cfp, ci);
              }
              case VM_METHOD_TYPE_BMETHOD:{
                CI_SET_FASTPATH(ci, vm_call_bmethod, enable_fastpath);
                return vm_call_bmethod(th, cfp, ci);
              }
              case VM_METHOD_TYPE_ZSUPER:{
                klass = ci->me->klass;
                klass = RCLASS_ORIGIN(klass);
              zsuper_method_dispatch:
                klass = RCLASS_SUPER(klass);
                if (!klass) {
                    ci->me = 0;
                    goto start_method_dispatch;
                }
                ci_temp = *ci;
                ci = &ci_temp;

                ci->me = rb_method_entry(klass, ci->mid, &ci->defined_class);

                if (ci->me != 0) {
                    goto normal_method_dispatch;
                }
                else {
                    goto start_method_dispatch;
                }
              }
              case VM_METHOD_TYPE_OPTIMIZED:{
                switch (ci->me->def->body.optimize_type) {
                  case OPTIMIZED_METHOD_TYPE_SEND:
                    CI_SET_FASTPATH(ci, vm_call_opt_send, enable_fastpath);
                    return vm_call_opt_send(th, cfp, ci);
                  case OPTIMIZED_METHOD_TYPE_CALL:
                    CI_SET_FASTPATH(ci, vm_call_opt_call, enable_fastpath);
                    return vm_call_opt_call(th, cfp, ci);
                  default:
                    rb_bug("vm_call_method: unsupported optimized method type (%d)",
                           ci->me->def->body.optimize_type);
                }
                break;
              }
              case VM_METHOD_TYPE_UNDEF:
                break;
              case VM_METHOD_TYPE_REFINED:{
                NODE *cref = rb_vm_get_cref(cfp->iseq, cfp->ep);
                VALUE refinements = cref ? cref->nd_refinements : Qnil;
                VALUE refinement, defined_class;
                rb_method_entry_t *me;

                refinement = find_refinement(refinements,
                                             ci->defined_class);
                if (NIL_P(refinement)) {
                    goto no_refinement_dispatch;
                }
                me = rb_method_entry(refinement, ci->mid, &defined_class);
                if (me) {
                    if (ci->call == vm_call_super_method) {
                        rb_control_frame_t *top_cfp = current_method_entry(th, cfp);
                        if (top_cfp->me &&
                            rb_method_definition_eq(me->def, top_cfp->me->def)) {
                            goto no_refinement_dispatch;
                        }
                    }
                    ci->me = me;
                    ci->defined_class = defined_class;
                    if (me->def->type != VM_METHOD_TYPE_REFINED) {
                        goto start_method_dispatch;
                    }
                }

              no_refinement_dispatch:
                if (ci->me->def->body.orig_me) {
                    ci->me = ci->me->def->body.orig_me;
                    if (UNDEFINED_METHOD_ENTRY_P(ci->me)) {
                        ci->me = 0;
                    }
                    goto start_method_dispatch;
                }
                else {
                    klass = ci->me->klass;
                    goto zsuper_method_dispatch;
                }
              }
            }
            rb_bug("vm_call_method: unsupported method type (%d)", ci->me->def->type);
        }
        else {
            int noex_safe;
            if (!(ci->flag & VM_CALL_FCALL) && (ci->me->flag & NOEX_MASK) & NOEX_PRIVATE) {
                int stat = NOEX_PRIVATE;

                if (ci->flag & VM_CALL_VCALL) {
                    stat |= NOEX_VCALL;
                }
                ci->aux.missing_reason = stat;
                CI_SET_FASTPATH(ci, vm_call_method_missing, 1);
                return vm_call_method_missing(th, cfp, ci);
            }
            else if (!(ci->flag & VM_CALL_OPT_SEND) && (ci->me->flag & NOEX_MASK) & NOEX_PROTECTED) {
                enable_fastpath = 0;
                if (!rb_obj_is_kind_of(cfp->self, ci->defined_class)) {
                    ci->aux.missing_reason = NOEX_PROTECTED;
                    return vm_call_method_missing(th, cfp, ci);
                }
                else {
                    goto normal_method_dispatch;
                }
            }
            else if ((noex_safe = NOEX_SAFE(ci->me->flag)) > th->safe_level && (noex_safe > 2)) {
                rb_raise(rb_eSecurityError, "calling insecure method: %s", rb_id2name(ci->mid));
            }
            else {
                goto normal_method_dispatch;
            }
        }
    }
    else {
        /* method missing */
        int stat = 0;
        if (ci->flag & VM_CALL_VCALL) {
            stat |= NOEX_VCALL;
        }
        if (ci->flag & VM_CALL_SUPER) {
            stat |= NOEX_SUPER;
        }
        if (ci->mid == idMethodMissing) {
            rb_control_frame_t *reg_cfp = cfp;
            VALUE *argv = STACK_ADDR_FROM_TOP(ci->argc);
            rb_raise_method_missing(th, ci->argc, argv, ci->recv, stat);
        }
        else {
            ci->aux.missing_reason = stat;
            CI_SET_FASTPATH(ci, vm_call_method_missing, 1);
            return vm_call_method_missing(th, cfp, ci);
        }
    }

    rb_bug("vm_call_method: unreachable");
}

static VALUE
vm_call_general(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci)
{
    return vm_call_method(th, reg_cfp, ci);
}

static VALUE
vm_call_super_method(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci)
{
    return vm_call_method(th, reg_cfp, ci);
}

/* super */

static inline VALUE
vm_search_normal_superclass(VALUE klass)
{
    if (BUILTIN_TYPE(klass) == T_ICLASS &&
        FL_TEST(RBASIC(klass)->klass, RMODULE_IS_REFINEMENT)) {
        klass = RBASIC(klass)->klass;
    }
    klass = RCLASS_ORIGIN(klass);
    return RCLASS_SUPER(klass);
}

static void
vm_super_outside(void)
{
    rb_raise(rb_eNoMethodError, "super called outside of method");
}

static int
vm_search_superclass(rb_control_frame_t *reg_cfp, rb_iseq_t *iseq, VALUE sigval, rb_call_info_t *ci)
{
    while (iseq && !iseq->klass) {
        iseq = iseq->parent_iseq;
    }

    if (iseq == 0) {
        return -1;
    }

    ci->mid = iseq->defined_method_id;

    if (iseq != iseq->local_iseq) {
        /* defined by Module#define_method() */
        rb_control_frame_t *lcfp = GET_CFP();

        if (!sigval) {
            /* zsuper */
            return -2;
        }

        while (lcfp->iseq != iseq) {
            rb_thread_t *th = GET_THREAD();
            VALUE *tep = VM_EP_PREV_EP(lcfp->ep);
            while (1) {
                lcfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(lcfp);
                if (RUBY_VM_CONTROL_FRAME_STACK_OVERFLOW_P(th, lcfp)) {
                    return -1;
                }
                if (lcfp->ep == tep) {
                    break;
                }
            }
        }

        /* temporary measure for [Bug #2420] [Bug #3136] */
        if (!lcfp->me) {
            return -1;
        }

        ci->mid = lcfp->me->def->original_id;
        ci->klass = vm_search_normal_superclass(lcfp->klass);
    }
    else {
        ci->klass = vm_search_normal_superclass(reg_cfp->klass);
    }

    return 0;
}

static void
vm_search_super_method(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci)
{
    VALUE current_defined_class;
    rb_iseq_t *iseq = GET_ISEQ();
    VALUE sigval = TOPN(ci->argc);

    current_defined_class = GET_CFP()->klass;
    if (NIL_P(current_defined_class)) {
        vm_super_outside();
    }

    if (!NIL_P(RCLASS_REFINED_CLASS(current_defined_class))) {
        current_defined_class = RCLASS_REFINED_CLASS(current_defined_class);
    }

    if (BUILTIN_TYPE(current_defined_class) != T_MODULE &&
        BUILTIN_TYPE(current_defined_class) != T_ICLASS && /* bound UnboundMethod */
        !FL_TEST(current_defined_class, RMODULE_INCLUDED_INTO_REFINEMENT) &&
        !rb_obj_is_kind_of(ci->recv, current_defined_class)) {
        VALUE m = RB_TYPE_P(current_defined_class, T_ICLASS) ?
            RBASIC(current_defined_class)->klass : current_defined_class;

        rb_raise(rb_eTypeError,
                 "self has wrong type to call super in this context: "
                 "%"PRIsVALUE" (expected %"PRIsVALUE")",
                 rb_obj_class(ci->recv), m);
    }

    switch (vm_search_superclass(GET_CFP(), iseq, sigval, ci)) {
      case -1:
        vm_super_outside();
      case -2:
        rb_raise(rb_eRuntimeError,
                 "implicit argument passing of super from method defined"
                 " by define_method() is not supported."
                 " Specify all arguments explicitly.");
    }
    if (!ci->klass) {
        /* bound instance method of module */
        ci->aux.missing_reason = NOEX_SUPER;
        CI_SET_FASTPATH(ci, vm_call_method_missing, 1);
        return;
    }

    /* TODO: use inline cache */
    ci->me = rb_method_entry(ci->klass, ci->mid, &ci->defined_class);
    ci->call = vm_call_super_method;

    while (iseq && !iseq->klass) {
        iseq = iseq->parent_iseq;
    }

    if (ci->me && ci->me->def->type == VM_METHOD_TYPE_ISEQ && ci->me->def->body.iseq == iseq) {
        ci->klass = RCLASS_SUPER(ci->defined_class);
        ci->me = rb_method_entry(ci->klass, ci->mid, &ci->defined_class);
    }
}

/* yield */

static inline int
block_proc_is_lambda(const VALUE procval)
{
    rb_proc_t *proc;

    if (procval) {
        GetProcPtr(procval, proc);
        return proc->is_lambda;
    }
    else {
        return 0;
    }
}

static inline VALUE
vm_yield_with_cfunc(rb_thread_t *th, const rb_block_t *block,
                    VALUE self, int argc, const VALUE *argv,
                    const rb_block_t *blockargptr)
{
    NODE *ifunc = (NODE *) block->iseq;
    VALUE val, arg, blockarg;
    int lambda = block_proc_is_lambda(block->proc);

    if (lambda) {
        arg = rb_ary_new4(argc, argv);
    }
    else if (argc == 0) {
        arg = Qnil;
    }
    else {
        arg = argv[0];
    }

    if (blockargptr) {
        if (blockargptr->proc) {
            blockarg = blockargptr->proc;
        }
        else {
            blockarg = rb_vm_make_proc(th, blockargptr, rb_cProc);
        }
    }
    else {
        blockarg = Qnil;
    }

    vm_push_frame(th, (rb_iseq_t *)ifunc, VM_FRAME_MAGIC_IFUNC, self,
                  0, VM_ENVVAL_PREV_EP_PTR(block->ep), 0,
                  th->cfp->sp, 1, 0, 0);

    val = (*ifunc->nd_cfnc) (arg, ifunc->nd_tval, argc, argv, blockarg);

    th->cfp++;
    return val;
}


/*--
 * @brief on supplied all of optional, rest and post parameters.
 * @pre iseq is block style (not lambda style)
 */
static inline int
vm_yield_setup_block_args_complex(rb_thread_t *th, const rb_iseq_t *iseq,
                                  int argc, VALUE *argv)
{
    rb_num_t opt_pc = 0;
    int i;
    const int m = iseq->argc;
    const int r = iseq->arg_rest;
    int len = iseq->arg_post_len;
    int start = iseq->arg_post_start;
    int rsize = argc > m ? argc - m : 0;    /* # of arguments which did not consumed yet */
    int psize = rsize > len ? len : rsize;  /* # of post arguments */
    int osize = 0;  /* # of opt arguments */
    VALUE ary;

    /* reserves arguments for post parameters */
    rsize -= psize;

    if (iseq->arg_opts) {
        const int opts = iseq->arg_opts - 1;
        if (rsize > opts) {
            osize = opts;
            opt_pc = iseq->arg_opt_table[opts];
        }
        else {
            osize = rsize;
            opt_pc = iseq->arg_opt_table[rsize];
        }
    }
    rsize -= osize;

    if (0) {
        printf(" argc: %d\n", argc);
        printf("  len: %d\n", len);
        printf("start: %d\n", start);
        printf("rsize: %d\n", rsize);
    }

    if (r == -1) {
        /* copy post argument */
        MEMMOVE(&argv[start], &argv[m+osize], VALUE, psize);
    }
    else {
        ary = rb_ary_new4(rsize, &argv[r]);

        /* copy post argument */
        MEMMOVE(&argv[start], &argv[m+rsize+osize], VALUE, psize);
        argv[r] = ary;
    }

    for (i=psize; i<len; i++) {
        argv[start + i] = Qnil;
    }

    return (int)opt_pc;
}

static inline int
vm_yield_setup_block_args(rb_thread_t *th, const rb_iseq_t * iseq,
                          int orig_argc, VALUE *argv,
                          const rb_block_t *blockptr)
{
    int i;
    int argc = orig_argc;
    const int m = iseq->argc;
    const int min = m + iseq->arg_post_len;
    VALUE ary, arg0;
    VALUE keyword_hash = Qnil;
    int opt_pc = 0;

    th->mark_stack_len = argc;

    /*
     * yield [1, 2]
     *  => {|a|} => a = [1, 2]
     *  => {|a, b|} => a, b = [1, 2]
     */
    arg0 = argv[0];
    if (!(iseq->arg_simple & 0x02) &&                           /* exclude {|a|} */
        (min > 0 ||                                             /* positional arguments exist */
         iseq->arg_opts > 2 ||                                  /* multiple optional arguments exist */
         iseq->arg_keyword != -1 ||                             /* any keyword arguments */
         0) &&
        argc == 1 && !NIL_P(ary = rb_check_array_type(arg0))) { /* rhs is only an array */
        th->mark_stack_len = argc = RARRAY_LENINT(ary);

        CHECK_VM_STACK_OVERFLOW(th->cfp, argc);

        MEMCPY(argv, RARRAY_CONST_PTR(ary), VALUE, argc);
    }
    else {
        /* vm_push_frame current argv is at the top of sp because vm_invoke_block
         * set sp at the first element of argv.
         * Therefore when rb_check_array_type(arg0) called to_ary and called to_ary
         * or method_missing run vm_push_frame, it initializes local variables.
         * see also https://bugs.ruby-lang.org/issues/8484
         */
        argv[0] = arg0;
    }

    /* keyword argument */
    if (iseq->arg_keyword != -1) {
        argc = vm_callee_setup_keyword_arg(th, iseq, argc, min, argv, &keyword_hash);
    }

    for (i=argc; i<m; i++) {
        argv[i] = Qnil;
    }

    if (iseq->arg_rest == -1 && iseq->arg_opts == 0) {
        const int arg_size = iseq->arg_size;
        if (arg_size < argc) {
            /*
             * yield 1, 2
             * => {|a|} # truncate
             */
            th->mark_stack_len = argc = arg_size;
        }
    }
    else {
        int r = iseq->arg_rest;

        if (iseq->arg_post_len ||
            iseq->arg_opts) { /* TODO: implement simple version for (iseq->arg_post_len==0 && iseq->arg_opts > 0) */
            opt_pc = vm_yield_setup_block_args_complex(th, iseq, argc, argv);
        }
        else {
            if (argc < r) {
                /* yield 1
                 * => {|a, b, *r|}
                 */
                for (i=argc; i<r; i++) {
                    argv[i] = Qnil;
                }
                argv[r] = rb_ary_new();
            }
            else {
                argv[r] = rb_ary_new4(argc-r, &argv[r]);
            }
        }

        th->mark_stack_len = iseq->arg_size;
    }

    /* keyword argument */
    if (iseq->arg_keyword != -1) {
        int arg_keywords_end = iseq->arg_keyword - (iseq->arg_block != -1);
        for (i = iseq->arg_keywords; 0 < i; i--) {
            argv[arg_keywords_end - i] = Qnil;
        }
        argv[iseq->arg_keyword] = keyword_hash;
    }

    /* {|&b|} */
    if (iseq->arg_block != -1) {
        VALUE procval = Qnil;

        if (blockptr) {
            if (blockptr->proc == 0) {
                procval = rb_vm_make_proc(th, blockptr, rb_cProc);
            }
            else {
                procval = blockptr->proc;
            }
        }

        argv[iseq->arg_block] = procval;
    }

    th->mark_stack_len = 0;
    return opt_pc;
}

static inline int
vm_yield_setup_args(rb_thread_t * const th, const rb_iseq_t *iseq,
                    int argc, VALUE *argv, const rb_block_t *blockptr, int lambda)
{
    if (0) { /* for debug */
        printf("     argc: %d\n", argc);
        printf("iseq argc: %d\n", iseq->argc);
        printf("iseq opts: %d\n", iseq->arg_opts);
        printf("iseq rest: %d\n", iseq->arg_rest);
        printf("iseq post: %d\n", iseq->arg_post_len);
        printf("iseq blck: %d\n", iseq->arg_block);
        printf("iseq smpl: %d\n", iseq->arg_simple);
        printf("   lambda: %s\n", lambda ? "true" : "false");
    }

    if (lambda) {
        /* call as method */
        rb_call_info_t ci_entry;
        ci_entry.flag = 0;
        ci_entry.argc = argc;
        ci_entry.blockptr = (rb_block_t *)blockptr;
        vm_callee_setup_arg(th, &ci_entry, iseq, argv, 1);
        return ci_entry.aux.opt_pc;
    }
    else {
        return vm_yield_setup_block_args(th, iseq, argc, argv, blockptr);
    }
}

static VALUE
vm_invoke_block(rb_thread_t *th, rb_control_frame_t *reg_cfp, rb_call_info_t *ci)
{
    const rb_block_t *block = VM_CF_BLOCK_PTR(reg_cfp);
    rb_iseq_t *iseq;
    VALUE type = GET_ISEQ()->local_iseq->type;

    if ((type != ISEQ_TYPE_METHOD && type != ISEQ_TYPE_CLASS) || block == 0) {
        rb_vm_localjump_error("no block given (yield)", Qnil, 0);
    }
    iseq = block->iseq;

    if (UNLIKELY(ci->flag & VM_CALL_ARGS_SPLAT)) {
        vm_caller_setup_args(th, GET_CFP(), ci);
    }

    if (BUILTIN_TYPE(iseq) != T_NODE) {
        int opt_pc;
        const int arg_size = iseq->arg_size;
        int is_lambda = block_proc_is_lambda(block->proc);
        VALUE * const rsp = GET_SP() - ci->argc;
        SET_SP(rsp);

        opt_pc = vm_yield_setup_args(th, iseq, ci->argc, rsp, 0, is_lambda);

        vm_push_frame(th, iseq,
                      is_lambda ? VM_FRAME_MAGIC_LAMBDA : VM_FRAME_MAGIC_BLOCK,
                      block->self,
                      block->klass,
                      VM_ENVVAL_PREV_EP_PTR(block->ep),
                      iseq->iseq_encoded + opt_pc,
                      rsp + arg_size,
                      iseq->local_size - arg_size, 0, iseq->stack_max);

        return Qundef;
    }
    else {
        VALUE val = vm_yield_with_cfunc(th, block, block->self, ci->argc, STACK_ADDR_FROM_TOP(ci->argc), 0);
        POPN(ci->argc); /* TODO: should put before C/yield? */
        return val;
    }
}

static VALUE
vm_make_proc_with_iseq(rb_iseq_t *blockiseq)
{
    rb_block_t *blockptr;
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);

    if (cfp == 0) {
        rb_bug("vm_make_proc_with_iseq: unreachable");
    }

    blockptr = RUBY_VM_GET_BLOCK_PTR_IN_CFP(cfp);
    blockptr->iseq = blockiseq;
    blockptr->proc = 0;

    return rb_vm_make_proc(th, blockptr, rb_cProc);
}

static VALUE
vm_once_exec(rb_iseq_t *iseq)
{
    VALUE proc = vm_make_proc_with_iseq(iseq);
    return rb_proc_call_with_block(proc, 0, 0, Qnil);
}

static VALUE
vm_once_clear(VALUE data)
{
    union iseq_inline_storage_entry *is = (union iseq_inline_storage_entry *)data;
    is->once.running_thread = NULL;
    return Qnil;
}