ruby/vm_insnhelper.c

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

  vm_insnhelper.c - instruction helper functions.

  $Author$

  Copyright (C) 2007 Koichi Sasada

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

#include "ruby/internal/config.h"

#include <math.h>

#include "constant.h"
#include "debug_counter.h"
#include "internal.h"
#include "internal/class.h"
#include "internal/compar.h"
#include "internal/hash.h"
#include "internal/numeric.h"
#include "internal/proc.h"
#include "internal/random.h"
#include "internal/variable.h"
#include "internal/struct.h"
#include "variable.h"

/* finish iseq array */
#include "insns.inc"
#ifndef MJIT_HEADER
#include "insns_info.inc"
#endif

extern rb_method_definition_t *rb_method_definition_create(rb_method_type_t type, ID mid);
extern void rb_method_definition_set(const rb_method_entry_t *me, rb_method_definition_t *def, void *opts);
extern int rb_method_definition_eq(const rb_method_definition_t *d1, const rb_method_definition_t *d2);
extern VALUE rb_make_no_method_exception(VALUE exc, VALUE format, VALUE obj,
                                         int argc, const VALUE *argv, int priv);

#ifndef MJIT_HEADER
static const struct rb_callcache vm_empty_cc;
static const struct rb_callcache vm_empty_cc_for_super;
#endif

/* control stack frame */

static rb_control_frame_t *vm_get_ruby_level_caller_cfp(const rb_execution_context_t *ec, const rb_control_frame_t *cfp);

MJIT_STATIC VALUE
ruby_vm_special_exception_copy(VALUE exc)
{
    VALUE e = rb_obj_alloc(rb_class_real(RBASIC_CLASS(exc)));
    rb_obj_copy_ivar(e, exc);
    return e;
}

NORETURN(static void ec_stack_overflow(rb_execution_context_t *ec, int));
static void
ec_stack_overflow(rb_execution_context_t *ec, int setup)
{
    VALUE mesg = rb_ec_vm_ptr(ec)->special_exceptions[ruby_error_sysstack];
    ec->raised_flag = RAISED_STACKOVERFLOW;
    if (setup) {
        VALUE at = rb_ec_backtrace_object(ec);
        mesg = ruby_vm_special_exception_copy(mesg);
        rb_ivar_set(mesg, idBt, at);
        rb_ivar_set(mesg, idBt_locations, at);
    }
    ec->errinfo = mesg;
    EC_JUMP_TAG(ec, TAG_RAISE);
}

NORETURN(static void vm_stackoverflow(void));
#ifdef MJIT_HEADER
NOINLINE(static COLDFUNC void vm_stackoverflow(void));
#endif

static void
vm_stackoverflow(void)
{
    ec_stack_overflow(GET_EC(), TRUE);
}

NORETURN(MJIT_STATIC void rb_ec_stack_overflow(rb_execution_context_t *ec, int crit));
MJIT_STATIC void
rb_ec_stack_overflow(rb_execution_context_t *ec, int crit)
{
    if (rb_during_gc()) {
        rb_bug("system stack overflow during GC. Faulty native extension?");
    }
    if (crit) {
        ec->raised_flag = RAISED_STACKOVERFLOW;
        ec->errinfo = rb_ec_vm_ptr(ec)->special_exceptions[ruby_error_stackfatal];
        EC_JUMP_TAG(ec, TAG_RAISE);
    }
#ifdef USE_SIGALTSTACK
    ec_stack_overflow(ec, TRUE);
#else
    ec_stack_overflow(ec, FALSE);
#endif
}


#if VM_CHECK_MODE > 0
static int
callable_class_p(VALUE klass)
{
#if VM_CHECK_MODE >= 2
    if (!klass) return FALSE;
    switch (RB_BUILTIN_TYPE(klass)) {
      default:
        break;
      case T_ICLASS:
        if (!RB_TYPE_P(RCLASS_SUPER(klass), T_MODULE)) break;
      case T_MODULE:
        return TRUE;
    }
    while (klass) {
        if (klass == rb_cBasicObject) {
            return TRUE;
        }
        klass = RCLASS_SUPER(klass);
    }
    return FALSE;
#else
    return klass != 0;
#endif
}

static int
callable_method_entry_p(const rb_callable_method_entry_t *cme)
{
    if (cme == NULL) {
        return TRUE;
    }
    else {
        VM_ASSERT(IMEMO_TYPE_P((VALUE)cme, imemo_ment));

        if (callable_class_p(cme->defined_class)) {
            return TRUE;
        }
        else {
            return FALSE;
        }
    }
}

static void
vm_check_frame_detail(VALUE type, int req_block, int req_me, int req_cref, VALUE specval, VALUE cref_or_me, int is_cframe, const rb_iseq_t *iseq)
{
    unsigned int magic = (unsigned int)(type & VM_FRAME_MAGIC_MASK);
    enum imemo_type cref_or_me_type = imemo_env; /* impossible value */

    if (RB_TYPE_P(cref_or_me, T_IMEMO)) {
        cref_or_me_type = imemo_type(cref_or_me);
    }
    if (type & VM_FRAME_FLAG_BMETHOD) {
        req_me = TRUE;
    }

    if (req_block && (type & VM_ENV_FLAG_LOCAL) == 0) {
        rb_bug("vm_push_frame: specval (%p) should be a block_ptr on %x frame", (void *)specval, magic);
    }
    if (!req_block && (type & VM_ENV_FLAG_LOCAL) != 0) {
        rb_bug("vm_push_frame: specval (%p) should not be a block_ptr on %x frame", (void *)specval, magic);
    }

    if (req_me) {
        if (cref_or_me_type != imemo_ment) {
            rb_bug("vm_push_frame: (%s) should be method entry on %x frame", rb_obj_info(cref_or_me), magic);
        }
    }
    else {
        if (req_cref && cref_or_me_type != imemo_cref) {
            rb_bug("vm_push_frame: (%s) should be CREF on %x frame", rb_obj_info(cref_or_me), magic);
        }
        else { /* cref or Qfalse */
            if (cref_or_me != Qfalse && cref_or_me_type != imemo_cref) {
                if (((type & VM_FRAME_FLAG_LAMBDA) || magic == VM_FRAME_MAGIC_IFUNC) && (cref_or_me_type == imemo_ment)) {
                    /* ignore */
                }
                else {
                    rb_bug("vm_push_frame: (%s) should be false or cref on %x frame", rb_obj_info(cref_or_me), magic);
                }
            }
        }
    }

    if (cref_or_me_type == imemo_ment) {
        const rb_callable_method_entry_t *me = (const rb_callable_method_entry_t *)cref_or_me;

        if (!callable_method_entry_p(me)) {
            rb_bug("vm_push_frame: ment (%s) should be callable on %x frame.", rb_obj_info(cref_or_me), magic);
        }
    }

    if ((type & VM_FRAME_MAGIC_MASK) == VM_FRAME_MAGIC_DUMMY) {
        VM_ASSERT(iseq == NULL ||
                  RUBY_VM_NORMAL_ISEQ_P(iseq) /* argument error. it should be fixed */);
    }
    else {
        VM_ASSERT(is_cframe == !RUBY_VM_NORMAL_ISEQ_P(iseq));
    }
}

static void
vm_check_frame(VALUE type,
               VALUE specval,
               VALUE cref_or_me,
               const rb_iseq_t *iseq)
{
    VALUE given_magic = type & VM_FRAME_MAGIC_MASK;
    VM_ASSERT(FIXNUM_P(type));

#define CHECK(magic, req_block, req_me, req_cref, is_cframe) \
    case magic: \
      vm_check_frame_detail(type, req_block, req_me, req_cref, \
                            specval, cref_or_me, is_cframe, iseq); \
      break
    switch (given_magic) {
        /*                           BLK    ME     CREF   CFRAME */
        CHECK(VM_FRAME_MAGIC_METHOD, TRUE,  TRUE,  FALSE, FALSE);
        CHECK(VM_FRAME_MAGIC_CLASS,  TRUE,  FALSE, TRUE,  FALSE);
        CHECK(VM_FRAME_MAGIC_TOP,    TRUE,  FALSE, TRUE,  FALSE);
        CHECK(VM_FRAME_MAGIC_CFUNC,  TRUE,  TRUE,  FALSE, TRUE);
        CHECK(VM_FRAME_MAGIC_BLOCK,  FALSE, FALSE, FALSE, FALSE);
        CHECK(VM_FRAME_MAGIC_IFUNC,  FALSE, FALSE, FALSE, TRUE);
        CHECK(VM_FRAME_MAGIC_EVAL,   FALSE, FALSE, FALSE, FALSE);
        CHECK(VM_FRAME_MAGIC_RESCUE, FALSE, FALSE, FALSE, FALSE);
        CHECK(VM_FRAME_MAGIC_DUMMY,  TRUE,  FALSE, FALSE, FALSE);
      default:
        rb_bug("vm_push_frame: unknown type (%x)", (unsigned int)given_magic);
    }
#undef CHECK
}

static VALUE vm_stack_canary; /* Initialized later */
static bool vm_stack_canary_was_born = false;

#ifndef MJIT_HEADER
MJIT_FUNC_EXPORTED void
rb_vm_check_canary(const rb_execution_context_t *ec, VALUE *sp)
{
    const struct rb_control_frame_struct *reg_cfp = ec->cfp;
    const struct rb_iseq_struct *iseq;

    if (! LIKELY(vm_stack_canary_was_born)) {
        return; /* :FIXME: isn't it rather fatal to enter this branch?  */
    }
    else if ((VALUE *)reg_cfp == ec->vm_stack + ec->vm_stack_size) {
        /* This is at the very beginning of a thread. cfp does not exist. */
        return;
    }
    else if (! (iseq = GET_ISEQ())) {
        return;
    }
    else if (LIKELY(sp[0] != vm_stack_canary)) {
        return;
    }
    else {
        /* we are going to call methods below; squash the canary to
         * prevent infinite loop. */
        sp[0] = Qundef;
    }

    const VALUE *orig = rb_iseq_original_iseq(iseq);
    const VALUE *encoded = ISEQ_BODY(iseq)->iseq_encoded;
    const ptrdiff_t pos = GET_PC() - encoded;
    const enum ruby_vminsn_type insn = (enum ruby_vminsn_type)orig[pos];
    const char *name = insn_name(insn);
    const VALUE iseqw = rb_iseqw_new(iseq);
    const VALUE inspection = rb_inspect(iseqw);
    const char *stri = rb_str_to_cstr(inspection);
    const VALUE disasm = rb_iseq_disasm(iseq);
    const char *strd = rb_str_to_cstr(disasm);

    /* rb_bug() is not capable of outputting this large contents.  It
       is designed to run form a SIGSEGV handler, which tends to be
       very restricted. */
    ruby_debug_printf(
        "We are killing the stack canary set by %s, "
        "at %s@pc=%"PRIdPTR"\n"
        "watch out the C stack trace.\n"
        "%s",
        name, stri, pos, strd);
    rb_bug("see above.");
}
#endif
#define vm_check_canary(ec, sp) rb_vm_check_canary(ec, sp)

#else
#define vm_check_canary(ec, sp)
#define vm_check_frame(a, b, c, d)
#endif /* VM_CHECK_MODE > 0 */

#if USE_DEBUG_COUNTER
static void
vm_push_frame_debug_counter_inc(
    const struct rb_execution_context_struct *ec,
    const struct rb_control_frame_struct *reg_cfp,
    VALUE type)
{
    const struct rb_control_frame_struct *prev_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(reg_cfp);

    RB_DEBUG_COUNTER_INC(frame_push);

    if (RUBY_VM_END_CONTROL_FRAME(ec) != prev_cfp) {
        const bool curr = VM_FRAME_RUBYFRAME_P(reg_cfp);
        const bool prev = VM_FRAME_RUBYFRAME_P(prev_cfp);
        if (prev) {
            if (curr) {
                RB_DEBUG_COUNTER_INC(frame_R2R);
            }
            else {
                RB_DEBUG_COUNTER_INC(frame_R2C);
            }
        }
        else {
            if (curr) {
                RB_DEBUG_COUNTER_INC(frame_C2R);
            }
            else {
                RB_DEBUG_COUNTER_INC(frame_C2C);
            }
        }
    }

    switch (type & VM_FRAME_MAGIC_MASK) {
      case VM_FRAME_MAGIC_METHOD: RB_DEBUG_COUNTER_INC(frame_push_method); return;
      case VM_FRAME_MAGIC_BLOCK:  RB_DEBUG_COUNTER_INC(frame_push_block);  return;
      case VM_FRAME_MAGIC_CLASS:  RB_DEBUG_COUNTER_INC(frame_push_class);  return;
      case VM_FRAME_MAGIC_TOP:    RB_DEBUG_COUNTER_INC(frame_push_top);    return;
      case VM_FRAME_MAGIC_CFUNC:  RB_DEBUG_COUNTER_INC(frame_push_cfunc);  return;
      case VM_FRAME_MAGIC_IFUNC:  RB_DEBUG_COUNTER_INC(frame_push_ifunc);  return;
      case VM_FRAME_MAGIC_EVAL:   RB_DEBUG_COUNTER_INC(frame_push_eval);   return;
      case VM_FRAME_MAGIC_RESCUE: RB_DEBUG_COUNTER_INC(frame_push_rescue); return;
      case VM_FRAME_MAGIC_DUMMY:  RB_DEBUG_COUNTER_INC(frame_push_dummy);  return;
    }

    rb_bug("unreachable");
}
#else
#define vm_push_frame_debug_counter_inc(ec, cfp, t) /* void */
#endif

STATIC_ASSERT(VM_ENV_DATA_INDEX_ME_CREF, VM_ENV_DATA_INDEX_ME_CREF == -2);
STATIC_ASSERT(VM_ENV_DATA_INDEX_SPECVAL, VM_ENV_DATA_INDEX_SPECVAL == -1);
STATIC_ASSERT(VM_ENV_DATA_INDEX_FLAGS,   VM_ENV_DATA_INDEX_FLAGS   == -0);

static void
vm_push_frame(rb_execution_context_t *ec,
              const rb_iseq_t *iseq,
              VALUE type,
              VALUE self,
              VALUE specval,
              VALUE cref_or_me,
              const VALUE *pc,
              VALUE *sp,
              int local_size,
              int stack_max)
{
    rb_control_frame_t *const cfp = RUBY_VM_NEXT_CONTROL_FRAME(ec->cfp);

    vm_check_frame(type, specval, cref_or_me, iseq);
    VM_ASSERT(local_size >= 0);

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

    /* setup vm value stack */

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

    /* setup ep with managing data */
    *sp++ = cref_or_me; /* ep[-2] / Qnil or T_IMEMO(cref) or T_IMEMO(ment) */
    *sp++ = specval     /* ep[-1] / block handler or prev env ptr */;
    *sp++ = type;       /* ep[-0] / ENV_FLAGS */

    /* setup new frame */
    *cfp = (const struct rb_control_frame_struct) {
        .pc         = pc,
        .sp         = sp,
        .iseq       = iseq,
        .self       = self,
        .ep         = sp - 1,
        .block_code = NULL,
        .__bp__     = sp, /* Store initial value of ep as bp to skip calculation cost of bp on JIT cancellation. */
#if VM_DEBUG_BP_CHECK
        .bp_check   = sp,
#endif
        .jit_return = NULL
    };

    ec->cfp = cfp;

    if (VMDEBUG == 2) {
        SDR();
    }
    vm_push_frame_debug_counter_inc(ec, cfp, type);
}

/* return TRUE if the frame is finished */
static inline int
vm_pop_frame(rb_execution_context_t *ec, rb_control_frame_t *cfp, const VALUE *ep)
{
    VALUE flags = ep[VM_ENV_DATA_INDEX_FLAGS];

    if (VM_CHECK_MODE >= 4) rb_gc_verify_internal_consistency();
    if (VMDEBUG == 2)       SDR();

    RUBY_VM_CHECK_INTS(ec);
    ec->cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);

    return flags & VM_FRAME_FLAG_FINISH;
}

MJIT_STATIC void
rb_vm_pop_frame(rb_execution_context_t *ec)
{
    vm_pop_frame(ec, ec->cfp, ec->cfp->ep);
}

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

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

/* lvar */

NOINLINE(static void vm_env_write_slowpath(const VALUE *ep, int index, VALUE v));

static void
vm_env_write_slowpath(const VALUE *ep, int index, VALUE v)
{
    /* remember env value forcely */
    rb_gc_writebarrier_remember(VM_ENV_ENVVAL(ep));
    VM_FORCE_WRITE(&ep[index], v);
    VM_ENV_FLAGS_UNSET(ep, VM_ENV_FLAG_WB_REQUIRED);
    RB_DEBUG_COUNTER_INC(lvar_set_slowpath);
}

static inline void
vm_env_write(const VALUE *ep, int index, VALUE v)
{
    VALUE flags = ep[VM_ENV_DATA_INDEX_FLAGS];
    if (LIKELY((flags & VM_ENV_FLAG_WB_REQUIRED) == 0)) {
        VM_STACK_ENV_WRITE(ep, index, v);
    }
    else {
        vm_env_write_slowpath(ep, index, v);
    }
}

MJIT_STATIC VALUE
rb_vm_bh_to_procval(const rb_execution_context_t *ec, VALUE block_handler)
{
    if (block_handler == VM_BLOCK_HANDLER_NONE) {
        return Qnil;
    }
    else {
        switch (vm_block_handler_type(block_handler)) {
          case block_handler_type_iseq:
          case block_handler_type_ifunc:
            return rb_vm_make_proc(ec, VM_BH_TO_CAPT_BLOCK(block_handler), rb_cProc);
          case block_handler_type_symbol:
            return rb_sym_to_proc(VM_BH_TO_SYMBOL(block_handler));
          case block_handler_type_proc:
            return VM_BH_TO_PROC(block_handler);
          default:
            VM_UNREACHABLE(rb_vm_bh_to_procval);
        }
    }
}

/* svar */

#if VM_CHECK_MODE > 0
static int
vm_svar_valid_p(VALUE svar)
{
    if (RB_TYPE_P((VALUE)svar, T_IMEMO)) {
        switch (imemo_type(svar)) {
          case imemo_svar:
          case imemo_cref:
          case imemo_ment:
            return TRUE;
          default:
            break;
        }
    }
    rb_bug("vm_svar_valid_p: unknown type: %s", rb_obj_info(svar));
    return FALSE;
}
#endif

static inline struct vm_svar *
lep_svar(const rb_execution_context_t *ec, const VALUE *lep)
{
    VALUE svar;

    if (lep && (ec == NULL || ec->root_lep != lep)) {
        svar = lep[VM_ENV_DATA_INDEX_ME_CREF];
    }
    else {
        svar = ec->root_svar;
    }

    VM_ASSERT(svar == Qfalse || vm_svar_valid_p(svar));

    return (struct vm_svar *)svar;
}

static inline void
lep_svar_write(const rb_execution_context_t *ec, const VALUE *lep, const struct vm_svar *svar)
{
    VM_ASSERT(vm_svar_valid_p((VALUE)svar));

    if (lep && (ec == NULL || ec->root_lep != lep)) {
        vm_env_write(lep, VM_ENV_DATA_INDEX_ME_CREF, (VALUE)svar);
    }
    else {
        RB_OBJ_WRITE(rb_ec_thread_ptr(ec)->self, &ec->root_svar, svar);
    }
}

static VALUE
lep_svar_get(const rb_execution_context_t *ec, const VALUE *lep, rb_num_t key)
{
    const struct vm_svar *svar = lep_svar(ec, lep);

    if ((VALUE)svar == Qfalse || imemo_type((VALUE)svar) != imemo_svar) return Qnil;

    switch (key) {
      case VM_SVAR_LASTLINE:
        return svar->lastline;
      case VM_SVAR_BACKREF:
        return svar->backref;
      default: {
        const VALUE ary = svar->others;

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

static struct vm_svar *
svar_new(VALUE obj)
{
    return (struct vm_svar *)rb_imemo_new(imemo_svar, Qnil, Qnil, Qnil, obj);
}

static void
lep_svar_set(const rb_execution_context_t *ec, const VALUE *lep, rb_num_t key, VALUE val)
{
    struct vm_svar *svar = lep_svar(ec, lep);

    if ((VALUE)svar == Qfalse || imemo_type((VALUE)svar) != imemo_svar) {
        lep_svar_write(ec, lep, svar = svar_new((VALUE)svar));
    }

    switch (key) {
      case VM_SVAR_LASTLINE:
        RB_OBJ_WRITE(svar, &svar->lastline, val);
        return;
      case VM_SVAR_BACKREF:
        RB_OBJ_WRITE(svar, &svar->backref, val);
        return;
      default: {
        VALUE ary = svar->others;

        if (NIL_P(ary)) {
            RB_OBJ_WRITE(svar, &svar->others, ary = rb_ary_new());
        }
        rb_ary_store(ary, key - VM_SVAR_EXTRA_START, val);
      }
    }
}

static inline VALUE
vm_getspecial(const rb_execution_context_t *ec, const VALUE *lep, rb_num_t key, rb_num_t type)
{
    VALUE val;

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

        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;
}

PUREFUNC(static rb_callable_method_entry_t *check_method_entry(VALUE obj, int can_be_svar));
static rb_callable_method_entry_t *
check_method_entry(VALUE obj, int can_be_svar)
{
    if (obj == Qfalse) return NULL;

#if VM_CHECK_MODE > 0
    if (!RB_TYPE_P(obj, T_IMEMO)) rb_bug("check_method_entry: unknown type: %s", rb_obj_info(obj));
#endif

    switch (imemo_type(obj)) {
      case imemo_ment:
        return (rb_callable_method_entry_t *)obj;
      case imemo_cref:
        return NULL;
      case imemo_svar:
        if (can_be_svar) {
            return check_method_entry(((struct vm_svar *)obj)->cref_or_me, FALSE);
        }
      default:
#if VM_CHECK_MODE > 0
        rb_bug("check_method_entry: svar should not be there:");
#endif
        return NULL;
    }
}

MJIT_STATIC const rb_callable_method_entry_t *
rb_vm_frame_method_entry(const rb_control_frame_t *cfp)
{
    const VALUE *ep = cfp->ep;
    rb_callable_method_entry_t *me;

    while (!VM_ENV_LOCAL_P(ep)) {
        if ((me = check_method_entry(ep[VM_ENV_DATA_INDEX_ME_CREF], FALSE)) != NULL) return me;
        ep = VM_ENV_PREV_EP(ep);
    }

    return check_method_entry(ep[VM_ENV_DATA_INDEX_ME_CREF], TRUE);
}

static const rb_iseq_t *
method_entry_iseqptr(const rb_callable_method_entry_t *me)
{
    switch (me->def->type) {
      case VM_METHOD_TYPE_ISEQ:
        return me->def->body.iseq.iseqptr;
      default:
        return NULL;
    }
}

static rb_cref_t *
method_entry_cref(const rb_callable_method_entry_t *me)
{
    switch (me->def->type) {
      case VM_METHOD_TYPE_ISEQ:
        return me->def->body.iseq.cref;
      default:
        return NULL;
    }
}

#if VM_CHECK_MODE == 0
PUREFUNC(static rb_cref_t *check_cref(VALUE, int));
#endif
static rb_cref_t *
check_cref(VALUE obj, int can_be_svar)
{
    if (obj == Qfalse) return NULL;

#if VM_CHECK_MODE > 0
    if (!RB_TYPE_P(obj, T_IMEMO)) rb_bug("check_cref: unknown type: %s", rb_obj_info(obj));
#endif

    switch (imemo_type(obj)) {
      case imemo_ment:
        return method_entry_cref((rb_callable_method_entry_t *)obj);
      case imemo_cref:
        return (rb_cref_t *)obj;
      case imemo_svar:
        if (can_be_svar) {
            return check_cref(((struct vm_svar *)obj)->cref_or_me, FALSE);
        }
      default:
#if VM_CHECK_MODE > 0
        rb_bug("check_method_entry: svar should not be there:");
#endif
        return NULL;
    }
}

static inline rb_cref_t *
vm_env_cref(const VALUE *ep)
{
    rb_cref_t *cref;

    while (!VM_ENV_LOCAL_P(ep)) {
        if ((cref = check_cref(ep[VM_ENV_DATA_INDEX_ME_CREF], FALSE)) != NULL) return cref;
        ep = VM_ENV_PREV_EP(ep);
    }

    return check_cref(ep[VM_ENV_DATA_INDEX_ME_CREF], TRUE);
}

static int
is_cref(const VALUE v, int can_be_svar)
{
    if (RB_TYPE_P(v, T_IMEMO)) {
        switch (imemo_type(v)) {
          case imemo_cref:
            return TRUE;
          case imemo_svar:
            if (can_be_svar) return is_cref(((struct vm_svar *)v)->cref_or_me, FALSE);
          default:
            break;
        }
    }
    return FALSE;
}

static int
vm_env_cref_by_cref(const VALUE *ep)
{
    while (!VM_ENV_LOCAL_P(ep)) {
        if (is_cref(ep[VM_ENV_DATA_INDEX_ME_CREF], FALSE)) return TRUE;
        ep = VM_ENV_PREV_EP(ep);
    }
    return is_cref(ep[VM_ENV_DATA_INDEX_ME_CREF], TRUE);
}

static rb_cref_t *
cref_replace_with_duplicated_cref_each_frame(const VALUE *vptr, int can_be_svar, VALUE parent)
{
    const VALUE v = *vptr;
    rb_cref_t *cref, *new_cref;

    if (RB_TYPE_P(v, T_IMEMO)) {
        switch (imemo_type(v)) {
          case imemo_cref:
            cref = (rb_cref_t *)v;
            new_cref = vm_cref_dup(cref);
            if (parent) {
                RB_OBJ_WRITE(parent, vptr, new_cref);
            }
            else {
                VM_FORCE_WRITE(vptr, (VALUE)new_cref);
            }
            return (rb_cref_t *)new_cref;
          case imemo_svar:
            if (can_be_svar) {
                return cref_replace_with_duplicated_cref_each_frame(&((struct vm_svar *)v)->cref_or_me, FALSE, v);
            }
            /* fall through */
          case imemo_ment:
            rb_bug("cref_replace_with_duplicated_cref_each_frame: unreachable");
          default:
            break;
        }
    }
    return FALSE;
}

static rb_cref_t *
vm_cref_replace_with_duplicated_cref(const VALUE *ep)
{
    if (vm_env_cref_by_cref(ep)) {
        rb_cref_t *cref;
        VALUE envval;

        while (!VM_ENV_LOCAL_P(ep)) {
            envval = VM_ENV_ESCAPED_P(ep) ? VM_ENV_ENVVAL(ep) : Qfalse;
            if ((cref = cref_replace_with_duplicated_cref_each_frame(&ep[VM_ENV_DATA_INDEX_ME_CREF], FALSE, envval)) != NULL) {
                return cref;
            }
            ep = VM_ENV_PREV_EP(ep);
        }
        envval = VM_ENV_ESCAPED_P(ep) ? VM_ENV_ENVVAL(ep) : Qfalse;
        return cref_replace_with_duplicated_cref_each_frame(&ep[VM_ENV_DATA_INDEX_ME_CREF], TRUE, envval);
    }
    else {
        rb_bug("vm_cref_dup: unreachable");
    }
}

static rb_cref_t *
vm_get_cref(const VALUE *ep)
{
    rb_cref_t *cref = vm_env_cref(ep);

    if (cref != NULL) {
        return cref;
    }
    else {
        rb_bug("vm_get_cref: unreachable");
    }
}

rb_cref_t *
rb_vm_get_cref(const VALUE *ep)
{
    return vm_get_cref(ep);
}

static rb_cref_t *
vm_ec_cref(const rb_execution_context_t *ec)
{
    const rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(ec, ec->cfp);

    if (cfp == NULL) {
        return NULL;
    }
    return vm_get_cref(cfp->ep);
}

static const rb_cref_t *
vm_get_const_key_cref(const VALUE *ep)
{
    const rb_cref_t *cref = vm_get_cref(ep);
    const rb_cref_t *key_cref = cref;

    while (cref) {
        if (FL_TEST(CREF_CLASS(cref), FL_SINGLETON) ||
            FL_TEST(CREF_CLASS(cref), RCLASS_CLONED)) {
            return key_cref;
        }
        cref = CREF_NEXT(cref);
    }

    /* does not include singleton class */
    return NULL;
}

void
rb_vm_rewrite_cref(rb_cref_t *cref, VALUE old_klass, VALUE new_klass, rb_cref_t **new_cref_ptr)
{
    rb_cref_t *new_cref;

    while (cref) {
        if (CREF_CLASS(cref) == old_klass) {
            new_cref = vm_cref_new_use_prev(new_klass, METHOD_VISI_UNDEF, FALSE, cref, FALSE);
            *new_cref_ptr = new_cref;
            return;
        }
        new_cref = vm_cref_new_use_prev(CREF_CLASS(cref), METHOD_VISI_UNDEF, FALSE, cref, FALSE);
        cref = CREF_NEXT(cref);
        *new_cref_ptr = new_cref;
        new_cref_ptr = &new_cref->next;
    }
    *new_cref_ptr = NULL;
}

static rb_cref_t *
vm_cref_push(const rb_execution_context_t *ec, VALUE klass, const VALUE *ep, int pushed_by_eval, int singleton)
{
    rb_cref_t *prev_cref = NULL;

    if (ep) {
        prev_cref = vm_env_cref(ep);
    }
    else {
        rb_control_frame_t *cfp = vm_get_ruby_level_caller_cfp(ec, ec->cfp);

        if (cfp) {
            prev_cref = vm_env_cref(cfp->ep);
        }
    }

    return vm_cref_new(klass, METHOD_VISI_PUBLIC, FALSE, prev_cref, pushed_by_eval, singleton);
}

static inline VALUE
vm_get_cbase(const VALUE *ep)
{
    const rb_cref_t *cref = vm_get_cref(ep);

    return CREF_CLASS_FOR_DEFINITION(cref);
}

static inline VALUE
vm_get_const_base(const VALUE *ep)
{
    const rb_cref_t *cref = vm_get_cref(ep);

    while (cref) {
        if (!CREF_PUSHED_BY_EVAL(cref)) {
            return CREF_CLASS_FOR_DEFINITION(cref);
        }
        cref = CREF_NEXT(cref);
    }

    return Qundef;
}

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

static inline void
vm_ensure_not_refinement_module(VALUE self)
{
    if (RB_TYPE_P(self, T_MODULE) && FL_TEST(self, RMODULE_IS_REFINEMENT)) {
        rb_warn("not defined at the refinement, but at the outer class/module");
    }
}

static inline VALUE
vm_get_iclass(const rb_control_frame_t *cfp, VALUE klass)
{
    return klass;
}

static inline VALUE
vm_get_ev_const(rb_execution_context_t *ec, VALUE orig_klass, ID id, bool allow_nil, int is_defined)
{
    void rb_const_warn_if_deprecated(const rb_const_entry_t *ce, VALUE klass, ID id);
    VALUE val;

    if (NIL_P(orig_klass) && allow_nil) {
        /* in current lexical scope */
        const rb_cref_t *root_cref = vm_get_cref(ec->cfp->ep);
        const rb_cref_t *cref;
        VALUE klass = Qnil;

        while (root_cref && CREF_PUSHED_BY_EVAL(root_cref)) {
            root_cref = CREF_NEXT(root_cref);
        }
        cref = root_cref;
        while (cref && CREF_NEXT(cref)) {
            if (CREF_PUSHED_BY_EVAL(cref)) {
                klass = Qnil;
            }
            else {
                klass = CREF_CLASS(cref);
            }
            cref = CREF_NEXT(cref);

            if (!NIL_P(klass)) {
                VALUE av, am = 0;
                rb_const_entry_t *ce;
              search_continue:
                if ((ce = rb_const_lookup(klass, id))) {
                    rb_const_warn_if_deprecated(ce, klass, id);
                    val = ce->value;
                    if (val == Qundef) {
                        if (am == klass) break;
                        am = klass;
                        if (is_defined) return 1;
                        if (rb_autoloading_value(klass, id, &av, NULL)) return av;
                        rb_autoload_load(klass, id);
                        goto search_continue;
                    }
                    else {
                        if (is_defined) {
                            return 1;
                        }
                        else {
                            if (UNLIKELY(!rb_ractor_main_p())) {
                                if (!rb_ractor_shareable_p(val)) {
                                    rb_raise(rb_eRactorIsolationError,
                                             "can not access non-shareable objects in constant %"PRIsVALUE"::%s by non-main ractor.", rb_class_path(klass), rb_id2name(id));
                                }
                            }
                            return val;
                        }
                    }
                }
            }
        }

        /* search self */
        if (root_cref && !NIL_P(CREF_CLASS(root_cref))) {
            klass = vm_get_iclass(ec->cfp, CREF_CLASS(root_cref));
        }
        else {
            klass = CLASS_OF(ec->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_ev_const_chain(rb_execution_context_t *ec, const ID *segments)
{
    VALUE val = Qnil;
    int idx = 0;
    int allow_nil = TRUE;
    if (segments[0] == idNULL) {
        val = rb_cObject;
        idx++;
        allow_nil = FALSE;
    }
    while (segments[idx]) {
        ID id = segments[idx++];
        val = vm_get_ev_const(ec, val, id, allow_nil, 0);
        allow_nil = FALSE;
    }
    return val;
}


static inline VALUE
vm_get_cvar_base(const rb_cref_t *cref, const rb_control_frame_t *cfp, int top_level_raise)
{
    VALUE klass;

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

    while (CREF_NEXT(cref) &&
           (NIL_P(CREF_CLASS(cref)) || FL_TEST(CREF_CLASS(cref), FL_SINGLETON) ||
            CREF_PUSHED_BY_EVAL(cref) || CREF_SINGLETON(cref))) {
        cref = CREF_NEXT(cref);
    }
    if (top_level_raise && !CREF_NEXT(cref)) {
        rb_raise(rb_eRuntimeError, "class variable access from toplevel");
    }

    klass = vm_get_iclass(cfp, CREF_CLASS(cref));

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

static bool
iv_index_tbl_lookup(struct st_table *iv_index_tbl, ID id, struct rb_iv_index_tbl_entry **ent)
{
    int found;
    st_data_t ent_data;

    if (iv_index_tbl == NULL) return false;

    RB_VM_LOCK_ENTER();
    {
        found = st_lookup(iv_index_tbl, (st_data_t)id, &ent_data);
    }
    RB_VM_LOCK_LEAVE();
    if (found) *ent = (struct rb_iv_index_tbl_entry *)ent_data;

    return found ? true : false;
}

ALWAYS_INLINE(static void fill_ivar_cache(const rb_iseq_t *iseq, IVC ic, const struct rb_callcache *cc, int is_attr, struct rb_iv_index_tbl_entry *ent));

static inline void
fill_ivar_cache(const rb_iseq_t *iseq, IVC ic, const struct rb_callcache *cc, int is_attr, struct rb_iv_index_tbl_entry *ent)
{
    // fill cache
    if (!is_attr) {
        vm_ic_entry_set(ic, ent, iseq);
    }
    else {
        vm_cc_attr_index_set(cc, ent->index);
    }
}

ALWAYS_INLINE(static VALUE vm_getivar(VALUE, ID, const rb_iseq_t *, IVC, const struct rb_callcache *, int));
static inline VALUE
vm_getivar(VALUE obj, ID id, const rb_iseq_t *iseq, IVC ic, const struct rb_callcache *cc, int is_attr)
{
#if OPT_IC_FOR_IVAR
    VALUE val = Qundef;

    if (SPECIAL_CONST_P(obj)) {
        // frozen?
    }
    else if (LIKELY(is_attr ?
                    RB_DEBUG_COUNTER_INC_UNLESS(ivar_get_ic_miss_unset, vm_cc_attr_index_p(cc)) :
                    RB_DEBUG_COUNTER_INC_UNLESS(ivar_get_ic_miss_serial, vm_ic_entry_p(ic) && ic->entry->class_serial == RCLASS_SERIAL(RBASIC(obj)->klass)))) {
        uint32_t index = !is_attr ? vm_ic_entry_index(ic): (vm_cc_attr_index(cc));

        RB_DEBUG_COUNTER_INC(ivar_get_ic_hit);

        if (LIKELY(BUILTIN_TYPE(obj) == T_OBJECT) &&
            LIKELY(index < ROBJECT_NUMIV(obj))) {
            val = ROBJECT_IVPTR(obj)[index];

            VM_ASSERT(rb_ractor_shareable_p(obj) ? rb_ractor_shareable_p(val) : true);
        }
        else if (FL_TEST_RAW(obj, FL_EXIVAR)) {
            val = rb_ivar_generic_lookup_with_index(obj, id, index);
        }

        goto ret;
    }
    else {
        struct rb_iv_index_tbl_entry *ent;

        if (BUILTIN_TYPE(obj) == T_OBJECT) {
            struct st_table *iv_index_tbl = ROBJECT_IV_INDEX_TBL(obj);

            if (iv_index_tbl && iv_index_tbl_lookup(iv_index_tbl, id, &ent)) {
                fill_ivar_cache(iseq, ic, cc, is_attr, ent);

                // get value
                if (ent->index < ROBJECT_NUMIV(obj)) {
                    val = ROBJECT_IVPTR(obj)[ent->index];

                    VM_ASSERT(rb_ractor_shareable_p(obj) ? rb_ractor_shareable_p(val) : true);
                }
            }
        }
        else if (FL_TEST_RAW(obj, FL_EXIVAR)) {
            struct st_table *iv_index_tbl = RCLASS_IV_INDEX_TBL(rb_obj_class(obj));

            if (iv_index_tbl && iv_index_tbl_lookup(iv_index_tbl, id, &ent)) {
                fill_ivar_cache(iseq, ic, cc, is_attr, ent);
                val = rb_ivar_generic_lookup_with_index(obj, id, ent->index);
            }
        }
        else {
            // T_CLASS / T_MODULE
            goto general_path;
        }

      ret:
        if (LIKELY(val != Qundef)) {
            return val;
        }
        else {
            return Qnil;
        }
    }
  general_path:
#endif /* OPT_IC_FOR_IVAR */
    RB_DEBUG_COUNTER_INC(ivar_get_ic_miss);

    if (is_attr) {
        return rb_attr_get(obj, id);
    }
    else {
        return rb_ivar_get(obj, id);
    }
}

ALWAYS_INLINE(static VALUE vm_setivar_slowpath(VALUE obj, ID id, VALUE val, const rb_iseq_t *iseq, IVC ic, const struct rb_callcache *cc, int is_attr));
NOINLINE(static VALUE vm_setivar_slowpath_ivar(VALUE obj, ID id, VALUE val, const rb_iseq_t *iseq, IVC ic));
NOINLINE(static VALUE vm_setivar_slowpath_attr(VALUE obj, ID id, VALUE val, const struct rb_callcache *cc));

static VALUE
vm_setivar_slowpath(VALUE obj, ID id, VALUE val, const rb_iseq_t *iseq, IVC ic, const struct rb_callcache *cc, int is_attr)
{
    rb_check_frozen_internal(obj);

#if OPT_IC_FOR_IVAR
    if (RB_TYPE_P(obj, T_OBJECT)) {
        struct st_table *iv_index_tbl = ROBJECT_IV_INDEX_TBL(obj);
        struct rb_iv_index_tbl_entry *ent;

        if (iv_index_tbl_lookup(iv_index_tbl, id, &ent)) {
            if (!is_attr) {
                vm_ic_entry_set(ic, ent, iseq);
            }
            else if (ent->index >= INT_MAX) {
                rb_raise(rb_eArgError, "too many instance variables");
            }
            else {
                vm_cc_attr_index_set(cc, (int)(ent->index));
            }

            uint32_t index = ent->index;

            if (UNLIKELY(index >= ROBJECT_NUMIV(obj))) {
                rb_init_iv_list(obj);
            }
            VALUE *ptr = ROBJECT_IVPTR(obj);
            RB_OBJ_WRITE(obj, &ptr[index], val);
            RB_DEBUG_COUNTER_INC(ivar_set_ic_miss_iv_hit);

            return val;
        }
    }
#endif
    RB_DEBUG_COUNTER_INC(ivar_set_ic_miss);
    return rb_ivar_set(obj, id, val);
}

static VALUE
vm_setivar_slowpath_ivar(VALUE obj, ID id, VALUE val, const rb_iseq_t *iseq, IVC ic)
{
    return vm_setivar_slowpath(obj, id, val, iseq, ic, NULL, false);
}

static VALUE
vm_setivar_slowpath_attr(VALUE obj, ID id, VALUE val, const struct rb_callcache *cc)
{
    return vm_setivar_slowpath(obj, id, val, NULL, NULL, cc, true);
}

static inline VALUE
vm_setivar(VALUE obj, ID id, VALUE val, const rb_iseq_t *iseq, IVC ic, const struct rb_callcache *cc, int is_attr)
{
#if OPT_IC_FOR_IVAR
    if (LIKELY(RB_TYPE_P(obj, T_OBJECT)) &&
        LIKELY(!RB_OBJ_FROZEN_RAW(obj))) {

        VM_ASSERT(!rb_ractor_shareable_p(obj));

        if (LIKELY(
            (!is_attr && RB_DEBUG_COUNTER_INC_UNLESS(ivar_set_ic_miss_serial, vm_ic_entry_p(ic) && ic->entry->class_serial == RCLASS_SERIAL(RBASIC(obj)->klass))) ||
            ( is_attr && RB_DEBUG_COUNTER_INC_UNLESS(ivar_set_ic_miss_unset, vm_cc_attr_index_p(cc))))) {
            uint32_t index = !is_attr ? vm_ic_entry_index(ic) : vm_cc_attr_index(cc);

            if (UNLIKELY(index >= ROBJECT_NUMIV(obj))) {
                rb_init_iv_list(obj);
            }
            VALUE *ptr = ROBJECT_IVPTR(obj);
            RB_OBJ_WRITE(obj, &ptr[index], val);
            RB_DEBUG_COUNTER_INC(ivar_set_ic_hit);
            return val; /* inline cache hit */
        }
    }
    else {
        RB_DEBUG_COUNTER_INC(ivar_set_ic_miss_noobject);
    }
#endif /* OPT_IC_FOR_IVAR */
    if (is_attr) {
        return vm_setivar_slowpath_attr(obj, id, val, cc);
    }
    else {
        return vm_setivar_slowpath_ivar(obj, id, val, iseq, ic);
    }
}

static VALUE
update_classvariable_cache(const rb_iseq_t *iseq, VALUE klass, ID id, ICVARC ic)
{
    VALUE defined_class = 0;
    VALUE cvar_value = rb_cvar_find(klass, id, &defined_class);

    if (RB_TYPE_P(defined_class, T_ICLASS)) {
        defined_class = RBASIC(defined_class)->klass;
    }

    struct rb_id_table *rb_cvc_tbl = RCLASS_CVC_TBL(defined_class);
    if (!rb_cvc_tbl) {
        rb_bug("the cvc table should be set");
    }

    VALUE ent_data;
    if (!rb_id_table_lookup(rb_cvc_tbl, id, &ent_data)) {
        rb_bug("should have cvar cache entry");
    }

    struct rb_cvar_class_tbl_entry *ent = (void *)ent_data;
    ent->global_cvar_state = GET_GLOBAL_CVAR_STATE();

    ic->entry = ent;
    RB_OBJ_WRITTEN(iseq, Qundef, ent->class_value);

    return cvar_value;
}

static inline VALUE
vm_getclassvariable(const rb_iseq_t *iseq, const rb_control_frame_t *reg_cfp, ID id, ICVARC ic)
{
    const rb_cref_t *cref;

    if (ic->entry && ic->entry->global_cvar_state == GET_GLOBAL_CVAR_STATE()) {
        VALUE v = Qundef;
        RB_DEBUG_COUNTER_INC(cvar_read_inline_hit);

        if (st_lookup(RCLASS_IV_TBL(ic->entry->class_value), (st_data_t)id, &v) &&
            LIKELY(rb_ractor_main_p())) {

            return v;
        }
    }

    cref = vm_get_cref(GET_EP());
    VALUE klass = vm_get_cvar_base(cref, reg_cfp, 1);

    return update_classvariable_cache(iseq, klass, id, ic);
}

VALUE
rb_vm_getclassvariable(const rb_iseq_t *iseq, const rb_control_frame_t *cfp, ID id, ICVARC ic)
{
    return vm_getclassvariable(iseq, cfp, id, ic);
}

static inline void
vm_setclassvariable(const rb_iseq_t *iseq, const rb_control_frame_t *reg_cfp, ID id, VALUE val, ICVARC ic)
{
    const rb_cref_t *cref;

    if (ic->entry && ic->entry->global_cvar_state == GET_GLOBAL_CVAR_STATE()) {
        RB_DEBUG_COUNTER_INC(cvar_write_inline_hit);

        rb_class_ivar_set(ic->entry->class_value, id, val);
        return;
    }

    cref = vm_get_cref(GET_EP());
    VALUE klass = vm_get_cvar_base(cref, reg_cfp, 1);

    rb_cvar_set(klass, id, val);

    update_classvariable_cache(iseq, klass, id, ic);
}

void
rb_vm_setclassvariable(const rb_iseq_t *iseq, const rb_control_frame_t *cfp, ID id, VALUE val, ICVARC ic)
{
    vm_setclassvariable(iseq, cfp, id, val, ic);
}

static inline VALUE
vm_getinstancevariable(const rb_iseq_t *iseq, VALUE obj, ID id, IVC ic)
{
    return vm_getivar(obj, id, iseq, ic, NULL, FALSE);
}

static inline void
vm_setinstancevariable(const rb_iseq_t *iseq, VALUE obj, ID id, VALUE val, IVC ic)
{
    vm_setivar(obj, id, val, iseq, ic, 0, 0);
}

void
rb_vm_setinstancevariable(const rb_iseq_t *iseq, VALUE obj, ID id, VALUE val, IVC ic)
{
    vm_setinstancevariable(iseq, obj, id, val, ic);
}

/* Set the instance variable +val+ on object +obj+ at the +index+.
 * This function only works with T_OBJECT objects, so make sure
 * +obj+ is of type T_OBJECT before using this function.
 */
VALUE
rb_vm_set_ivar_idx(VALUE obj, uint32_t index, VALUE val)
{
    RUBY_ASSERT(RB_TYPE_P(obj, T_OBJECT));

    rb_check_frozen_internal(obj);

    VM_ASSERT(!rb_ractor_shareable_p(obj));

    if (UNLIKELY(index >= ROBJECT_NUMIV(obj))) {
        rb_init_iv_list(obj);
    }
    VALUE *ptr = ROBJECT_IVPTR(obj);
    RB_OBJ_WRITE(obj, &ptr[index], val);

    return val;
}

static VALUE
vm_throw_continue(const rb_execution_context_t *ec, VALUE err)
{
    /* continue throw */

    if (FIXNUM_P(err)) {
        ec->tag->state = FIX2INT(err);
    }
    else if (SYMBOL_P(err)) {
        ec->tag->state = TAG_THROW;
    }
    else if (THROW_DATA_P(err)) {
        ec->tag->state = THROW_DATA_STATE((struct vm_throw_data *)err);
    }
    else {
        ec->tag->state = TAG_RAISE;
    }
    return err;
}

static VALUE
vm_throw_start(const rb_execution_context_t *ec, rb_control_frame_t *const reg_cfp, enum ruby_tag_type state,
               const int flag, const VALUE throwobj)
{
    const rb_control_frame_t *escape_cfp = NULL;
    const rb_control_frame_t * const eocfp = RUBY_VM_END_CONTROL_FRAME(ec); /* end of control frame pointer */

    if (flag != 0) {
        /* do nothing */
    }
    else if (state == TAG_BREAK) {
        int is_orphan = 1;
        const VALUE *ep = GET_EP();
        const rb_iseq_t *base_iseq = GET_ISEQ();
        escape_cfp = reg_cfp;

        while (ISEQ_BODY(base_iseq)->type != ISEQ_TYPE_BLOCK) {
            if (ISEQ_BODY(escape_cfp->iseq)->type == ISEQ_TYPE_CLASS) {
                escape_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(escape_cfp);
                ep = escape_cfp->ep;
                base_iseq = escape_cfp->iseq;
            }
            else {
                ep = VM_ENV_PREV_EP(ep);
                base_iseq = ISEQ_BODY(base_iseq)->parent_iseq;
                escape_cfp = rb_vm_search_cf_from_ep(ec, escape_cfp, ep);
                VM_ASSERT(escape_cfp->iseq == base_iseq);
            }
        }

        if (VM_FRAME_LAMBDA_P(escape_cfp)) {
            /* lambda{... break ...} */
            is_orphan = 0;
            state = TAG_RETURN;
        }
        else {
            ep = VM_ENV_PREV_EP(ep);

            while (escape_cfp < eocfp) {
                if (escape_cfp->ep == ep) {
                    const rb_iseq_t *const iseq = escape_cfp->iseq;
                    const VALUE epc = escape_cfp->pc - ISEQ_BODY(iseq)->iseq_encoded;
                    const struct iseq_catch_table *const ct = ISEQ_BODY(iseq)->catch_table;
                    unsigned int i;

                    if (!ct) break;
                    for (i=0; i < ct->size; i++) {
                        const struct iseq_catch_table_entry *const entry =
                            UNALIGNED_MEMBER_PTR(ct, entries[i]);

                        if (entry->type == CATCH_TYPE_BREAK &&
                            entry->iseq == base_iseq &&
                            entry->start < epc && entry->end >= epc) {
                            if (entry->cont == epc) { /* found! */
                                is_orphan = 0;
                            }
                            break;
                        }
                    }
                    break;
                }

                escape_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(escape_cfp);
            }
        }

        if (is_orphan) {
            rb_vm_localjump_error("break from proc-closure", throwobj, TAG_BREAK);
        }
    }
    else if (state == TAG_RETRY) {
        const VALUE *ep = VM_ENV_PREV_EP(GET_EP());

        escape_cfp = rb_vm_search_cf_from_ep(ec, reg_cfp, ep);
    }
    else if (state == TAG_RETURN) {
        const VALUE *current_ep = GET_EP();
        const VALUE *target_ep = NULL, *target_lep, *ep = current_ep;
        int in_class_frame = 0;
        int toplevel = 1;
        escape_cfp = reg_cfp;

        // find target_lep, target_ep
        while (!VM_ENV_LOCAL_P(ep)) {
            if (VM_ENV_FLAGS(ep, VM_FRAME_FLAG_LAMBDA) && target_ep == NULL) {
                target_ep = ep;
            }
            ep = VM_ENV_PREV_EP(ep);
        }
        target_lep = ep;

        while (escape_cfp < eocfp) {
            const VALUE *lep = VM_CF_LEP(escape_cfp);

            if (!target_lep) {
                target_lep = lep;
            }

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

            if (lep == target_lep) {
                if (VM_FRAME_LAMBDA_P(escape_cfp)) {
                    toplevel = 0;
                    if (in_class_frame) {
                        /* lambda {class A; ... return ...; end} */
                        goto valid_return;
                    }
                    else {
                        const VALUE *tep = current_ep;

                        while (target_lep != tep) {
                            if (escape_cfp->ep == tep) {
                                /* in lambda */
                                if (tep == target_ep) {
                                    goto valid_return;
                                }
                                else {
                                    goto unexpected_return;
                                }
                            }
                            tep = VM_ENV_PREV_EP(tep);
                        }
                    }
                }
                else if (VM_FRAME_RUBYFRAME_P(escape_cfp)) {
                    switch (ISEQ_BODY(escape_cfp->iseq)->type) {
                      case ISEQ_TYPE_TOP:
                      case ISEQ_TYPE_MAIN:
                        if (toplevel) {
                            if (in_class_frame) goto unexpected_return;
                            if (target_ep == NULL) {
                                goto valid_return;
                            }
                            else {
                                goto unexpected_return;
                            }
                        }
                        break;
                      case ISEQ_TYPE_EVAL:
                      case ISEQ_TYPE_CLASS:
                        toplevel = 0;
                        break;
                      default:
                        break;
                    }
                }
            }

            if (escape_cfp->ep == target_lep && ISEQ_BODY(escape_cfp->iseq)->type == ISEQ_TYPE_METHOD) {
                if (target_ep == NULL) {
                    goto valid_return;
                }
                else {
                    goto unexpected_return;
                }
            }

            escape_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(escape_cfp);
        }
      unexpected_return:;
        rb_vm_localjump_error("unexpected return", throwobj, TAG_RETURN);

      valid_return:;
        /* do nothing */
    }
    else {
        rb_bug("isns(throw): unsupported throw type");
    }

    ec->tag->state = state;
    return (VALUE)THROW_DATA_NEW(throwobj, escape_cfp, state);
}

static VALUE
vm_throw(const rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
         rb_num_t throw_state, VALUE throwobj)
{
    const int state = (int)(throw_state & VM_THROW_STATE_MASK);
    const int flag = (int)(throw_state & VM_THROW_NO_ESCAPE_FLAG);

    if (state != 0) {
        return vm_throw_start(ec, reg_cfp, state, flag, throwobj);
    }
    else {
        return vm_throw_continue(ec, throwobj);
    }
}

static inline void
vm_expandarray(VALUE *sp, VALUE ary, rb_num_t num, int flag)
{
    int is_splat = flag & 0x01;
    rb_num_t space_size = num + is_splat;
    VALUE *base = sp - 1;
    const VALUE *ptr;
    rb_num_t len;
    const VALUE obj = ary;

    if (!RB_TYPE_P(ary, T_ARRAY) && NIL_P(ary = rb_check_array_type(ary))) {
        ary = obj;
        ptr = &ary;
        len = 1;
    }
    else {
        ptr = RARRAY_CONST_PTR_TRANSIENT(ary);
        len = (rb_num_t)RARRAY_LEN(ary);
    }

    if (space_size == 0) {
        /* no space left on stack */
    }
    else 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_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling);

static VALUE vm_mtbl_dump(VALUE klass, ID target_mid);

static struct rb_class_cc_entries *
vm_ccs_create(VALUE klass, const rb_callable_method_entry_t *cme)
{
    struct rb_class_cc_entries *ccs = ALLOC(struct rb_class_cc_entries);
#if VM_CHECK_MODE > 0
    ccs->debug_sig = ~(VALUE)ccs;
#endif
    ccs->capa = 0;
    ccs->len = 0;
    RB_OBJ_WRITE(klass, &ccs->cme, cme);
    METHOD_ENTRY_CACHED_SET((rb_callable_method_entry_t *)cme);
    ccs->entries = NULL;
    return ccs;
}

static void
vm_ccs_push(VALUE klass, struct rb_class_cc_entries *ccs, const struct rb_callinfo *ci, const struct rb_callcache *cc)
{
    if (! vm_cc_markable(cc)) {
        return;
    }
    else if (! vm_ci_markable(ci)) {
        return;
    }

    if (UNLIKELY(ccs->len == ccs->capa)) {
        if (ccs->capa == 0) {
            ccs->capa = 1;
            ccs->entries = ALLOC_N(struct rb_class_cc_entries_entry, ccs->capa);
        }
        else {
            ccs->capa *= 2;
            REALLOC_N(ccs->entries, struct rb_class_cc_entries_entry, ccs->capa);
        }
    }
    VM_ASSERT(ccs->len < ccs->capa);

    const int pos = ccs->len++;
    RB_OBJ_WRITE(klass, &ccs->entries[pos].ci, ci);
    RB_OBJ_WRITE(klass, &ccs->entries[pos].cc, cc);

    if (RB_DEBUG_COUNTER_SETMAX(ccs_maxlen, ccs->len)) {
        // for tuning
        // vm_mtbl_dump(klass, 0);
    }
}

#if VM_CHECK_MODE > 0
void
rb_vm_ccs_dump(struct rb_class_cc_entries *ccs)
{
    ruby_debug_printf("ccs:%p (%d,%d)\n", (void *)ccs, ccs->len, ccs->capa);
    for (int i=0; i<ccs->len; i++) {
        vm_ci_dump(ccs->entries[i].ci);
        rp(ccs->entries[i].cc);
    }
}

static int
vm_ccs_verify(struct rb_class_cc_entries *ccs, ID mid, VALUE klass)
{
    VM_ASSERT(vm_ccs_p(ccs));
    VM_ASSERT(ccs->len <= ccs->capa);

    for (int i=0; i<ccs->len; i++) {
        const struct rb_callinfo  *ci = ccs->entries[i].ci;
        const struct rb_callcache *cc = ccs->entries[i].cc;

        VM_ASSERT(vm_ci_p(ci));
        VM_ASSERT(vm_ci_mid(ci) == mid);
        VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
        VM_ASSERT(vm_cc_class_check(cc, klass));
        VM_ASSERT(vm_cc_check_cme(cc, ccs->cme));
    }
    return TRUE;
}
#endif

#ifndef MJIT_HEADER

static const rb_callable_method_entry_t *check_overloaded_cme(const rb_callable_method_entry_t *cme, const struct rb_callinfo * const ci);

static const struct rb_callcache *
vm_search_cc(const VALUE klass, const struct rb_callinfo * const ci)
{
    const ID mid = vm_ci_mid(ci);
    struct rb_id_table *cc_tbl = RCLASS_CC_TBL(klass);
    struct rb_class_cc_entries *ccs = NULL;
    VALUE ccs_data;

    if (cc_tbl) {
        if (rb_id_table_lookup(cc_tbl, mid, &ccs_data)) {
            ccs = (struct rb_class_cc_entries *)ccs_data;
            const int ccs_len = ccs->len;

            if (UNLIKELY(METHOD_ENTRY_INVALIDATED(ccs->cme))) {
                rb_vm_ccs_free(ccs);
                rb_id_table_delete(cc_tbl, mid);
                ccs = NULL;
            }
            else {
                VM_ASSERT(vm_ccs_verify(ccs, mid, klass));

                for (int i=0; i<ccs_len; i++) {
                    const struct rb_callinfo  *ccs_ci = ccs->entries[i].ci;
                    const struct rb_callcache *ccs_cc = ccs->entries[i].cc;

                    VM_ASSERT(vm_ci_p(ccs_ci));
                    VM_ASSERT(IMEMO_TYPE_P(ccs_cc, imemo_callcache));

                    if (ccs_ci == ci) { // TODO: equality
                        RB_DEBUG_COUNTER_INC(cc_found_in_ccs);

                        VM_ASSERT(vm_cc_cme(ccs_cc)->called_id == mid);
                        VM_ASSERT(ccs_cc->klass == klass);
                        VM_ASSERT(!METHOD_ENTRY_INVALIDATED(vm_cc_cme(ccs_cc)));

                        return ccs_cc;
                    }
                }
            }
        }
    }
    else {
        cc_tbl = RCLASS_CC_TBL(klass) = rb_id_table_create(2);
    }

    RB_DEBUG_COUNTER_INC(cc_not_found_in_ccs);

    const rb_callable_method_entry_t *cme;

    if (ccs) {
        cme = ccs->cme;
        cme = UNDEFINED_METHOD_ENTRY_P(cme) ? NULL : cme;

        VM_ASSERT(cme == rb_callable_method_entry(klass, mid));
    }
    else {
        cme = rb_callable_method_entry(klass, mid);
    }

    VM_ASSERT(cme == NULL || IMEMO_TYPE_P(cme, imemo_ment));

    if (cme == NULL) {
        // undef or not found: can't cache the information
        VM_ASSERT(vm_cc_cme(&vm_empty_cc) == NULL);
        return &vm_empty_cc;
    }

    VM_ASSERT(cme == rb_callable_method_entry(klass, mid));

    METHOD_ENTRY_CACHED_SET((struct rb_callable_method_entry_struct *)cme);

    if (ccs == NULL) {
        VM_ASSERT(cc_tbl != NULL);

        if (LIKELY(rb_id_table_lookup(cc_tbl, mid, &ccs_data))) {
            // rb_callable_method_entry() prepares ccs.
            ccs = (struct rb_class_cc_entries *)ccs_data;
        }
        else {
            // TODO: required?
            ccs = vm_ccs_create(klass, cme);
            rb_id_table_insert(cc_tbl, mid, (VALUE)ccs);
        }
    }

    cme = check_overloaded_cme(cme, ci);

    const struct rb_callcache *cc = vm_cc_new(klass, cme, vm_call_general);
    vm_ccs_push(klass, ccs, ci, cc);

    VM_ASSERT(vm_cc_cme(cc) != NULL);
    VM_ASSERT(cme->called_id == mid);
    VM_ASSERT(vm_cc_cme(cc)->called_id == mid);

    return cc;
}

MJIT_FUNC_EXPORTED const struct rb_callcache *
rb_vm_search_method_slowpath(const struct rb_callinfo *ci, VALUE klass)
{
    const struct rb_callcache *cc;

    VM_ASSERT(RB_TYPE_P(klass, T_CLASS) || RB_TYPE_P(klass, T_ICLASS));

    RB_VM_LOCK_ENTER();
    {
        cc = vm_search_cc(klass, ci);

        VM_ASSERT(cc);
        VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
        VM_ASSERT(cc == vm_cc_empty() || cc->klass == klass);
        VM_ASSERT(cc == vm_cc_empty() || callable_method_entry_p(vm_cc_cme(cc)));
        VM_ASSERT(cc == vm_cc_empty() || !METHOD_ENTRY_INVALIDATED(vm_cc_cme(cc)));
        VM_ASSERT(cc == vm_cc_empty() || vm_cc_cme(cc)->called_id == vm_ci_mid(ci));
    }
    RB_VM_LOCK_LEAVE();

    return cc;
}
#endif

static const struct rb_callcache *
vm_search_method_slowpath0(VALUE cd_owner, struct rb_call_data *cd, VALUE klass)
{
#if USE_DEBUG_COUNTER
    const struct rb_callcache *old_cc = cd->cc;
#endif

    const struct rb_callcache *cc = rb_vm_search_method_slowpath(cd->ci, klass);

#if OPT_INLINE_METHOD_CACHE
    cd->cc = cc;

    const struct rb_callcache *empty_cc =
#ifdef MJIT_HEADER
      rb_vm_empty_cc();
#else
      &vm_empty_cc;
#endif
    if (cd_owner && cc != empty_cc) RB_OBJ_WRITTEN(cd_owner, Qundef, cc);

#if USE_DEBUG_COUNTER
    if (old_cc == empty_cc) {
        // empty
        RB_DEBUG_COUNTER_INC(mc_inline_miss_empty);
    }
    else if (old_cc == cc) {
        RB_DEBUG_COUNTER_INC(mc_inline_miss_same_cc);
    }
    else if (vm_cc_cme(old_cc) == vm_cc_cme(cc)) {
        RB_DEBUG_COUNTER_INC(mc_inline_miss_same_cme);
    }
    else if (vm_cc_cme(old_cc) && vm_cc_cme(cc) &&
             vm_cc_cme(old_cc)->def == vm_cc_cme(cc)->def) {
        RB_DEBUG_COUNTER_INC(mc_inline_miss_same_def);
    }
    else {
        RB_DEBUG_COUNTER_INC(mc_inline_miss_diff);
    }
#endif
#endif // OPT_INLINE_METHOD_CACHE

    VM_ASSERT(vm_cc_cme(cc) == NULL ||
              vm_cc_cme(cc)->called_id == vm_ci_mid(cd->ci));

    return cc;
}

#ifndef MJIT_HEADER
ALWAYS_INLINE(static const struct rb_callcache *vm_search_method_fastpath(VALUE cd_owner, struct rb_call_data *cd, VALUE klass));
#endif
static const struct rb_callcache *
vm_search_method_fastpath(VALUE cd_owner, struct rb_call_data *cd, VALUE klass)
{
    const struct rb_callcache *cc = cd->cc;

#if OPT_INLINE_METHOD_CACHE
    if (LIKELY(vm_cc_class_check(cc, klass))) {
        if (LIKELY(!METHOD_ENTRY_INVALIDATED(vm_cc_cme(cc)))) {
            VM_ASSERT(callable_method_entry_p(vm_cc_cme(cc)));
            RB_DEBUG_COUNTER_INC(mc_inline_hit);
            VM_ASSERT(vm_cc_cme(cc) == NULL ||                        // not found
                      (vm_ci_flag(cd->ci) & VM_CALL_SUPER) ||         // search_super w/ define_method
                      vm_cc_cme(cc)->called_id == vm_ci_mid(cd->ci)); // cme->called_id == ci->mid

            return cc;
        }
        RB_DEBUG_COUNTER_INC(mc_inline_miss_invalidated);
    }
    else {
        RB_DEBUG_COUNTER_INC(mc_inline_miss_klass);
    }
#endif

    return vm_search_method_slowpath0(cd_owner, cd, klass);
}

static const struct rb_callcache *
vm_search_method(VALUE cd_owner, struct rb_call_data *cd, VALUE recv)
{
    VALUE klass = CLASS_OF(recv);
    VM_ASSERT(klass != Qfalse);
    VM_ASSERT(RBASIC_CLASS(klass) == 0 || rb_obj_is_kind_of(klass, rb_cClass));

    return vm_search_method_fastpath(cd_owner, cd, klass);
}

static inline int
check_cfunc(const rb_callable_method_entry_t *me, VALUE (*func)(ANYARGS))
{
    if (! me) {
        return false;
    }
    else {
        VM_ASSERT(IMEMO_TYPE_P(me, imemo_ment));
        VM_ASSERT(callable_method_entry_p(me));
        VM_ASSERT(me->def);
        if (me->def->type != VM_METHOD_TYPE_CFUNC) {
            return false;
        }
        else {
            return me->def->body.cfunc.func == func;
        }
    }
}

static inline int
vm_method_cfunc_is(const rb_iseq_t *iseq, CALL_DATA cd, VALUE recv, VALUE (*func)(ANYARGS))
{
    VM_ASSERT(iseq != NULL);
    const struct rb_callcache *cc = vm_search_method((VALUE)iseq, cd, recv);
    return check_cfunc(vm_cc_cme(cc), func);
}

#define EQ_UNREDEFINED_P(t) BASIC_OP_UNREDEFINED_P(BOP_EQ, t##_REDEFINED_OP_FLAG)

static inline bool
FIXNUM_2_P(VALUE a, VALUE b)
{
    /* FIXNUM_P(a) && FIXNUM_P(b)
     * == ((a & 1) && (b & 1))
     * == a & b & 1 */
    SIGNED_VALUE x = a;
    SIGNED_VALUE y = b;
    SIGNED_VALUE z = x & y & 1;
    return z == 1;
}

static inline bool
FLONUM_2_P(VALUE a, VALUE b)
{
#if USE_FLONUM
    /* FLONUM_P(a) && FLONUM_P(b)
     * == ((a & 3) == 2) && ((b & 3) == 2)
     * == ! ((a ^ 2) | (b ^ 2) & 3)
     */
    SIGNED_VALUE x = a;
    SIGNED_VALUE y = b;
    SIGNED_VALUE z = ((x ^ 2) | (y ^ 2)) & 3;
    return !z;
#else
    return false;
#endif
}

static VALUE
opt_equality_specialized(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) && EQ_UNREDEFINED_P(INTEGER)) {
        goto compare_by_identity;
    }
    else if (FLONUM_2_P(recv, obj) && EQ_UNREDEFINED_P(FLOAT)) {
        goto compare_by_identity;
    }
    else if (STATIC_SYM_P(recv) && STATIC_SYM_P(obj) && EQ_UNREDEFINED_P(SYMBOL)) {
        goto compare_by_identity;
    }
    else if (SPECIAL_CONST_P(recv)) {
        //
    }
    else if (RBASIC_CLASS(recv) == rb_cFloat && RB_FLOAT_TYPE_P(obj) && EQ_UNREDEFINED_P(FLOAT)) {
        double a = RFLOAT_VALUE(recv);
        double b = RFLOAT_VALUE(obj);

#if MSC_VERSION_BEFORE(1300)
        if (isnan(a)) {
            return Qfalse;
        }
        else if (isnan(b)) {
            return Qfalse;
        }
        else
#endif
        return RBOOL(a == b);
    }
    else if (RBASIC_CLASS(recv) == rb_cString && EQ_UNREDEFINED_P(STRING)) {
        if (recv == obj) {
            return Qtrue;
        }
        else if (RB_TYPE_P(obj, T_STRING)) {
            return rb_str_eql_internal(obj, recv);
        }
    }
    return Qundef;

  compare_by_identity:
    return RBOOL(recv == obj);
}

static VALUE
opt_equality(const rb_iseq_t *cd_owner, VALUE recv, VALUE obj, CALL_DATA cd)
{
    VM_ASSERT(cd_owner != NULL);

    VALUE val = opt_equality_specialized(recv, obj);
    if (val != Qundef) return val;

    if (!vm_method_cfunc_is(cd_owner, cd, recv, rb_obj_equal)) {
        return Qundef;
    }
    else {
        return RBOOL(recv == obj);
    }
}

#undef EQ_UNREDEFINED_P

#ifndef MJIT_HEADER

static inline const struct rb_callcache *gccct_method_search(rb_execution_context_t *ec, VALUE recv, ID mid, int argc); // vm_eval.c
NOINLINE(static VALUE opt_equality_by_mid_slowpath(VALUE recv, VALUE obj, ID mid));

static VALUE
opt_equality_by_mid_slowpath(VALUE recv, VALUE obj, ID mid)
{
    const struct rb_callcache *cc = gccct_method_search(GET_EC(), recv, mid, 1);

    if (cc && check_cfunc(vm_cc_cme(cc), rb_obj_equal)) {
        return RBOOL(recv == obj);
    }
    else {
        return Qundef;
    }
}

static VALUE
opt_equality_by_mid(VALUE recv, VALUE obj, ID mid)
{
    VALUE val = opt_equality_specialized(recv, obj);
    if (val != Qundef) {
        return val;
    }
    else {
        return opt_equality_by_mid_slowpath(recv, obj, mid);
    }
}

VALUE
rb_equal_opt(VALUE obj1, VALUE obj2)
{
    return opt_equality_by_mid(obj1, obj2, idEq);
}

VALUE
rb_eql_opt(VALUE obj1, VALUE obj2)
{
    return opt_equality_by_mid(obj1, obj2, idEqlP);
}

#endif // MJIT_HEADER

extern VALUE rb_vm_call0(rb_execution_context_t *ec, VALUE, ID, int, const VALUE*, const rb_callable_method_entry_t *, int kw_splat);
extern VALUE rb_vm_call_with_refinements(rb_execution_context_t *, VALUE, ID, int, const VALUE *, int);

static VALUE
check_match(rb_execution_context_t *ec, 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: {
        return rb_vm_call_with_refinements(ec, pattern, idEqq, 1, &target, RB_NO_KEYWORDS);
      }
      default:
        rb_bug("check_match: unreachable");
    }
}


#if MSC_VERSION_BEFORE(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 RBOOL(a < b);
}

static inline VALUE
double_cmp_le(double a, double b)
{
    CHECK_CMP_NAN(a, b);
    return RBOOL(a <= b);
}

static inline VALUE
double_cmp_gt(double a, double b)
{
    CHECK_CMP_NAN(a, b);
    return RBOOL(a > b);
}

static inline VALUE
double_cmp_ge(double a, double b)
{
    CHECK_CMP_NAN(a, b);
    return RBOOL(a >= b);
}

static inline VALUE *
vm_base_ptr(const rb_control_frame_t *cfp)
{
#if 0 // we may optimize and use this once we confirm it does not spoil performance on JIT.
    const rb_control_frame_t *prev_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);

    if (cfp->iseq && VM_FRAME_RUBYFRAME_P(cfp)) {
        VALUE *bp = prev_cfp->sp + ISEQ_BODY(cfp->iseq)->local_table_size + VM_ENV_DATA_SIZE;
        if (ISEQ_BODY(cfp->iseq)->type == ISEQ_TYPE_METHOD) {
            /* adjust `self' */
            bp += 1;
        }
#if VM_DEBUG_BP_CHECK
        if (bp != cfp->bp_check) {
            ruby_debug_printf("bp_check: %ld, bp: %ld\n",
                    (long)(cfp->bp_check - GET_EC()->vm_stack),
                    (long)(bp - GET_EC()->vm_stack));
            rb_bug("vm_base_ptr: unreachable");
        }
#endif
        return bp;
    }
    else {
        return NULL;
    }
#else
    return cfp->__bp__;
#endif
}

/* method call processes with call_info */

#include "vm_args.c"

static inline VALUE vm_call_iseq_setup_2(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling, int opt_pc, int param_size, int local_size);
ALWAYS_INLINE(static VALUE vm_call_iseq_setup_normal(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling, const rb_callable_method_entry_t *me, int opt_pc, int param_size, int local_size));
static inline VALUE vm_call_iseq_setup_tailcall(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling, int opt_pc);
static VALUE vm_call_super_method(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling);
static VALUE vm_call_method_nome(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling);
static VALUE vm_call_method_each_type(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling);
static inline VALUE vm_call_method(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling);

static vm_call_handler vm_call_iseq_setup_func(const struct rb_callinfo *ci, const int param_size, const int local_size);

static VALUE
vm_call_iseq_setup_tailcall_0start(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_iseq_setup_tailcall_0start);

    return vm_call_iseq_setup_tailcall(ec, cfp, calling, 0);
}

static VALUE
vm_call_iseq_setup_normal_0start(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_iseq_setup_0start);

    const struct rb_callcache *cc = calling->cc;
    const rb_iseq_t *iseq = def_iseq_ptr(vm_cc_cme(cc)->def);
    int param = ISEQ_BODY(iseq)->param.size;
    int local = ISEQ_BODY(iseq)->local_table_size;
    return vm_call_iseq_setup_normal(ec, cfp, calling, vm_cc_cme(cc), 0, param, local);
}

MJIT_STATIC bool
rb_simple_iseq_p(const rb_iseq_t *iseq)
{
    return ISEQ_BODY(iseq)->param.flags.has_opt == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_rest == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_post == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_kw == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_kwrest == FALSE &&
           ISEQ_BODY(iseq)->param.flags.accepts_no_kwarg == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_block == FALSE;
}

MJIT_FUNC_EXPORTED bool
rb_iseq_only_optparam_p(const rb_iseq_t *iseq)
{
    return ISEQ_BODY(iseq)->param.flags.has_opt == TRUE &&
           ISEQ_BODY(iseq)->param.flags.has_rest == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_post == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_kw == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_kwrest == FALSE &&
           ISEQ_BODY(iseq)->param.flags.accepts_no_kwarg == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_block == FALSE;
}

MJIT_FUNC_EXPORTED bool
rb_iseq_only_kwparam_p(const rb_iseq_t *iseq)
{
    return ISEQ_BODY(iseq)->param.flags.has_opt == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_rest == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_post == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_kw == TRUE &&
           ISEQ_BODY(iseq)->param.flags.has_kwrest == FALSE &&
           ISEQ_BODY(iseq)->param.flags.has_block == FALSE;
}

// If true, cc->call needs to include `CALLER_SETUP_ARG` (i.e. can't be skipped in fastpath)
MJIT_STATIC bool
rb_splat_or_kwargs_p(const struct rb_callinfo *restrict ci)
{
    return IS_ARGS_SPLAT(ci) || IS_ARGS_KW_OR_KW_SPLAT(ci);
}


static inline void
CALLER_SETUP_ARG(struct rb_control_frame_struct *restrict cfp,
                 struct rb_calling_info *restrict calling,
                 const struct rb_callinfo *restrict ci)
{
    if (UNLIKELY(IS_ARGS_SPLAT(ci))) {
        VALUE final_hash;
        /* This expands the rest argument to the stack.
         * So, vm_ci_flag(ci) & VM_CALL_ARGS_SPLAT is now inconsistent.
         */
        vm_caller_setup_arg_splat(cfp, calling);
        if (!IS_ARGS_KW_OR_KW_SPLAT(ci) &&
                calling->argc > 0 &&
                RB_TYPE_P((final_hash = *(cfp->sp - 1)), T_HASH) &&
                (((struct RHash *)final_hash)->basic.flags & RHASH_PASS_AS_KEYWORDS)) {
            *(cfp->sp - 1) = rb_hash_dup(final_hash);
            calling->kw_splat = 1;
        }
    }
    if (UNLIKELY(IS_ARGS_KW_OR_KW_SPLAT(ci))) {
        if (IS_ARGS_KEYWORD(ci)) {
            /* This converts VM_CALL_KWARG style to VM_CALL_KW_SPLAT style
             * by creating a keyword hash.
             * So, vm_ci_flag(ci) & VM_CALL_KWARG is now inconsistent.
             */
            vm_caller_setup_arg_kw(cfp, calling, ci);
        }
        else {
            VALUE keyword_hash = cfp->sp[-1];
            if (!RB_TYPE_P(keyword_hash, T_HASH)) {
                /* Convert a non-hash keyword splat to a new hash */
                cfp->sp[-1] = rb_hash_dup(rb_to_hash_type(keyword_hash));
            }
            else if (!IS_ARGS_KW_SPLAT_MUT(ci)) {
                /* Convert a hash keyword splat to a new hash unless
                 * a mutable keyword splat was passed.
                 */
                cfp->sp[-1] = rb_hash_dup(keyword_hash);
            }
        }
    }
}

static inline void
CALLER_REMOVE_EMPTY_KW_SPLAT(struct rb_control_frame_struct *restrict cfp,
                             struct rb_calling_info *restrict calling,
                             const struct rb_callinfo *restrict ci)
{
    if (UNLIKELY(calling->kw_splat)) {
        /* This removes the last Hash object if it is empty.
         * So, vm_ci_flag(ci) & VM_CALL_KW_SPLAT is now inconsistent.
         */
        if (RHASH_EMPTY_P(cfp->sp[-1])) {
            cfp->sp--;
            calling->argc--;
            calling->kw_splat = 0;
        }
    }
}

#define USE_OPT_HIST 0

#if USE_OPT_HIST
#define OPT_HIST_MAX 64
static int opt_hist[OPT_HIST_MAX+1];

__attribute__((destructor))
static void
opt_hist_show_results_at_exit(void)
{
    for (int i=0; i<OPT_HIST_MAX; i++) {
        ruby_debug_printf("opt_hist\t%d\t%d\n", i, opt_hist[i]);
    }
}
#endif

static VALUE
vm_call_iseq_setup_normal_opt_start(rb_execution_context_t *ec, rb_control_frame_t *cfp,
                                    struct rb_calling_info *calling)
{
    const struct rb_callcache *cc = calling->cc;
    const rb_iseq_t *iseq = def_iseq_ptr(vm_cc_cme(cc)->def);
    const int lead_num = ISEQ_BODY(iseq)->param.lead_num;
    const int opt = calling->argc - lead_num;
    const int opt_num = ISEQ_BODY(iseq)->param.opt_num;
    const int opt_pc = (int)ISEQ_BODY(iseq)->param.opt_table[opt];
    const int param = ISEQ_BODY(iseq)->param.size;
    const int local = ISEQ_BODY(iseq)->local_table_size;
    const int delta = opt_num - opt;

    RB_DEBUG_COUNTER_INC(ccf_iseq_opt);

#if USE_OPT_HIST
    if (opt_pc < OPT_HIST_MAX) {
        opt_hist[opt]++;
    }
    else {
        opt_hist[OPT_HIST_MAX]++;
    }
#endif

    return vm_call_iseq_setup_normal(ec, cfp, calling, vm_cc_cme(cc), opt_pc, param - delta, local);
}

static VALUE
vm_call_iseq_setup_tailcall_opt_start(rb_execution_context_t *ec, rb_control_frame_t *cfp,
                                      struct rb_calling_info *calling)
{
    const struct rb_callcache *cc = calling->cc;
    const rb_iseq_t *iseq = def_iseq_ptr(vm_cc_cme(cc)->def);
    const int lead_num = ISEQ_BODY(iseq)->param.lead_num;
    const int opt = calling->argc - lead_num;
    const int opt_pc = (int)ISEQ_BODY(iseq)->param.opt_table[opt];

    RB_DEBUG_COUNTER_INC(ccf_iseq_opt);

#if USE_OPT_HIST
    if (opt_pc < OPT_HIST_MAX) {
        opt_hist[opt]++;
    }
    else {
        opt_hist[OPT_HIST_MAX]++;
    }
#endif

    return vm_call_iseq_setup_tailcall(ec, cfp, calling, opt_pc);
}

static void
args_setup_kw_parameters(rb_execution_context_t *const ec, const rb_iseq_t *const iseq,
                         VALUE *const passed_values, const int passed_keyword_len, const VALUE *const passed_keywords,
                         VALUE *const locals);

static VALUE
vm_call_iseq_setup_kwparm_kwarg(rb_execution_context_t *ec, rb_control_frame_t *cfp,
                                struct rb_calling_info *calling)
{
    const struct rb_callinfo *ci = calling->ci;
    const struct rb_callcache *cc = calling->cc;

    VM_ASSERT(vm_ci_flag(ci) & VM_CALL_KWARG);
    RB_DEBUG_COUNTER_INC(ccf_iseq_kw1);

    const rb_iseq_t *iseq = def_iseq_ptr(vm_cc_cme(cc)->def);
    const struct rb_iseq_param_keyword *kw_param = ISEQ_BODY(iseq)->param.keyword;
    const struct rb_callinfo_kwarg *kw_arg = vm_ci_kwarg(ci);
    const int ci_kw_len = kw_arg->keyword_len;
    const VALUE * const ci_keywords = kw_arg->keywords;
    VALUE *argv = cfp->sp - calling->argc;
    VALUE *const klocals = argv + kw_param->bits_start - kw_param->num;
    const int lead_num = ISEQ_BODY(iseq)->param.lead_num;
    VALUE * const ci_kws = ALLOCA_N(VALUE, ci_kw_len);
    MEMCPY(ci_kws, argv + lead_num, VALUE, ci_kw_len);
    args_setup_kw_parameters(ec, iseq, ci_kws, ci_kw_len, ci_keywords, klocals);

    int param = ISEQ_BODY(iseq)->param.size;
    int local = ISEQ_BODY(iseq)->local_table_size;
    return vm_call_iseq_setup_normal(ec, cfp, calling, vm_cc_cme(cc), 0, param, local);
}

static VALUE
vm_call_iseq_setup_kwparm_nokwarg(rb_execution_context_t *ec, rb_control_frame_t *cfp,
                                  struct rb_calling_info *calling)
{
    const struct rb_callinfo *MAYBE_UNUSED(ci) = calling->ci;
    const struct rb_callcache *cc = calling->cc;

    VM_ASSERT((vm_ci_flag(ci) & VM_CALL_KWARG) == 0);
    RB_DEBUG_COUNTER_INC(ccf_iseq_kw2);

    const rb_iseq_t *iseq = def_iseq_ptr(vm_cc_cme(cc)->def);
    const struct rb_iseq_param_keyword *kw_param = ISEQ_BODY(iseq)->param.keyword;
    VALUE * const argv = cfp->sp - calling->argc;
    VALUE * const klocals = argv + kw_param->bits_start - kw_param->num;

    int i;
    for (i=0; i<kw_param->num; i++) {
        klocals[i] = kw_param->default_values[i];
    }
    klocals[i] = INT2FIX(0); // kw specify flag
    // NOTE:
    //   nobody check this value, but it should be cleared because it can
    //   points invalid VALUE (T_NONE objects, raw pointer and so on).

    int param = ISEQ_BODY(iseq)->param.size;
    int local = ISEQ_BODY(iseq)->local_table_size;
    return vm_call_iseq_setup_normal(ec, cfp, calling, vm_cc_cme(cc), 0, param, local);
}

static inline int
vm_callee_setup_arg(rb_execution_context_t *ec, struct rb_calling_info *calling,
                    const rb_iseq_t *iseq, VALUE *argv, int param_size, int local_size)
{
    const struct rb_callinfo *ci = calling->ci;
    const struct rb_callcache *cc = calling->cc;
    bool cacheable_ci = vm_ci_markable(ci);

    if (LIKELY(!(vm_ci_flag(ci) & VM_CALL_KW_SPLAT))) {
        if (LIKELY(rb_simple_iseq_p(iseq))) {
            rb_control_frame_t *cfp = ec->cfp;
            CALLER_SETUP_ARG(cfp, calling, ci);
            CALLER_REMOVE_EMPTY_KW_SPLAT(cfp, calling, ci);

            if (calling->argc != ISEQ_BODY(iseq)->param.lead_num) {
                argument_arity_error(ec, iseq, calling->argc, ISEQ_BODY(iseq)->param.lead_num, ISEQ_BODY(iseq)->param.lead_num);
            }

            VM_ASSERT(ci == calling->ci);
            VM_ASSERT(cc == calling->cc);
            CC_SET_FASTPATH(cc, vm_call_iseq_setup_func(ci, param_size, local_size), cacheable_ci && vm_call_iseq_optimizable_p(ci, cc));
            return 0;
        }
        else if (rb_iseq_only_optparam_p(iseq)) {
            rb_control_frame_t *cfp = ec->cfp;
            CALLER_SETUP_ARG(cfp, calling, ci);
            CALLER_REMOVE_EMPTY_KW_SPLAT(cfp, calling, ci);

            const int lead_num = ISEQ_BODY(iseq)->param.lead_num;
            const int opt_num = ISEQ_BODY(iseq)->param.opt_num;
            const int argc = calling->argc;
            const int opt = argc - lead_num;

            if (opt < 0 || opt > opt_num) {
                argument_arity_error(ec, iseq, argc, lead_num, lead_num + opt_num);
            }

            if (LIKELY(!(vm_ci_flag(ci) & VM_CALL_TAILCALL))) {
                CC_SET_FASTPATH(cc, vm_call_iseq_setup_normal_opt_start,
                                !IS_ARGS_SPLAT(ci) && !IS_ARGS_KEYWORD(ci) &&
                                cacheable_ci && vm_call_cacheable(ci, cc));
            }
            else {
                CC_SET_FASTPATH(cc, vm_call_iseq_setup_tailcall_opt_start,
                                !IS_ARGS_SPLAT(ci) && !IS_ARGS_KEYWORD(ci) &&
                                cacheable_ci && vm_call_cacheable(ci, cc));
            }

            /* initialize opt vars for self-references */
            VM_ASSERT((int)ISEQ_BODY(iseq)->param.size == lead_num + opt_num);
            for (int i=argc; i<lead_num + opt_num; i++) {
                argv[i] = Qnil;
            }
            return (int)ISEQ_BODY(iseq)->param.opt_table[opt];
        }
        else if (rb_iseq_only_kwparam_p(iseq) && !IS_ARGS_SPLAT(ci)) {
            const int lead_num = ISEQ_BODY(iseq)->param.lead_num;
            const int argc = calling->argc;
            const struct rb_iseq_param_keyword *kw_param = ISEQ_BODY(iseq)->param.keyword;

            if (vm_ci_flag(ci) & VM_CALL_KWARG) {
                const struct rb_callinfo_kwarg *kw_arg = vm_ci_kwarg(ci);

                if (argc - kw_arg->keyword_len == lead_num) {
                    const int ci_kw_len = kw_arg->keyword_len;
                    const VALUE * const ci_keywords = kw_arg->keywords;
                    VALUE * const ci_kws = ALLOCA_N(VALUE, ci_kw_len);
                    MEMCPY(ci_kws, argv + lead_num, VALUE, ci_kw_len);

                    VALUE *const klocals = argv + kw_param->bits_start - kw_param->num;
                    args_setup_kw_parameters(ec, iseq, ci_kws, ci_kw_len, ci_keywords, klocals);

                    CC_SET_FASTPATH(cc, vm_call_iseq_setup_kwparm_kwarg,
                                    cacheable_ci && vm_call_cacheable(ci, cc));

                    return 0;
                }
            }
            else if (argc == lead_num) {
                /* no kwarg */
                VALUE *const klocals = argv + kw_param->bits_start - kw_param->num;
                args_setup_kw_parameters(ec, iseq, NULL, 0, NULL, klocals);

                if (klocals[kw_param->num] == INT2FIX(0)) {
                    /* copy from default_values */
                    CC_SET_FASTPATH(cc, vm_call_iseq_setup_kwparm_nokwarg,
                                    cacheable_ci && vm_call_cacheable(ci, cc));
                }

                return 0;
            }
        }
    }

    return setup_parameters_complex(ec, iseq, calling, ci, argv, arg_setup_method);
}

static VALUE
vm_call_iseq_setup(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_iseq_setup);

    const struct rb_callcache *cc = calling->cc;
    const rb_iseq_t *iseq = def_iseq_ptr(vm_cc_cme(cc)->def);
    const int param_size = ISEQ_BODY(iseq)->param.size;
    const int local_size = ISEQ_BODY(iseq)->local_table_size;
    const int opt_pc = vm_callee_setup_arg(ec, calling, def_iseq_ptr(vm_cc_cme(cc)->def), cfp->sp - calling->argc, param_size, local_size);
    return vm_call_iseq_setup_2(ec, cfp, calling, opt_pc, param_size, local_size);
}

static inline VALUE
vm_call_iseq_setup_2(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling,
                     int opt_pc, int param_size, int local_size)
{
    const struct rb_callinfo *ci = calling->ci;
    const struct rb_callcache *cc = calling->cc;

    if (LIKELY(!(vm_ci_flag(ci) & VM_CALL_TAILCALL))) {
        return vm_call_iseq_setup_normal(ec, cfp, calling, vm_cc_cme(cc), opt_pc, param_size, local_size);
    }
    else {
        return vm_call_iseq_setup_tailcall(ec, cfp, calling, opt_pc);
    }
}

static inline VALUE
vm_call_iseq_setup_normal(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling, const rb_callable_method_entry_t *me,
                          int opt_pc, int param_size, int local_size)
{
    const rb_iseq_t *iseq = def_iseq_ptr(me->def);
    VALUE *argv = cfp->sp - calling->argc;
    VALUE *sp = argv + param_size;
    cfp->sp = argv - 1 /* recv */;

    vm_push_frame(ec, iseq, VM_FRAME_MAGIC_METHOD | VM_ENV_FLAG_LOCAL, calling->recv,
                  calling->block_handler, (VALUE)me,
                  ISEQ_BODY(iseq)->iseq_encoded + opt_pc, sp,
                  local_size - param_size,
                  ISEQ_BODY(iseq)->stack_max);
    return Qundef;
}

static inline VALUE
vm_call_iseq_setup_tailcall(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling, int opt_pc)
{
    const struct rb_callcache *cc = calling->cc;
    unsigned int i;
    VALUE *argv = cfp->sp - calling->argc;
    const rb_callable_method_entry_t *me = vm_cc_cme(cc);
    const rb_iseq_t *iseq = def_iseq_ptr(me->def);
    VALUE *src_argv = argv;
    VALUE *sp_orig, *sp;
    VALUE finish_flag = VM_FRAME_FINISHED_P(cfp) ? VM_FRAME_FLAG_FINISH : 0;

    if (VM_BH_FROM_CFP_P(calling->block_handler, cfp)) {
        struct rb_captured_block *dst_captured = VM_CFP_TO_CAPTURED_BLOCK(RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp));
        const struct rb_captured_block *src_captured = VM_BH_TO_CAPT_BLOCK(calling->block_handler);
        dst_captured->code.val = src_captured->code.val;
        if (VM_BH_ISEQ_BLOCK_P(calling->block_handler)) {
            calling->block_handler = VM_BH_FROM_ISEQ_BLOCK(dst_captured);
        }
        else {
            calling->block_handler = VM_BH_FROM_IFUNC_BLOCK(dst_captured);
        }
    }

    vm_pop_frame(ec, cfp, cfp->ep);
    cfp = ec->cfp;

    sp_orig = sp = cfp->sp;

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

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

    vm_push_frame(ec, iseq, VM_FRAME_MAGIC_METHOD | VM_ENV_FLAG_LOCAL | finish_flag,
                  calling->recv, calling->block_handler, (VALUE)me,
                  ISEQ_BODY(iseq)->iseq_encoded + opt_pc, sp,
                  ISEQ_BODY(iseq)->local_table_size - ISEQ_BODY(iseq)->param.size,
                  ISEQ_BODY(iseq)->stack_max);

    cfp->sp = sp_orig;

    return Qundef;
}

static void
ractor_unsafe_check(void)
{
    if (!rb_ractor_main_p()) {
        rb_raise(rb_eRactorUnsafeError, "ractor unsafe method called from not main ractor");
    }
}

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

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

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

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

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

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

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

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

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

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

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

static VALUE
call_cfunc_9(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    ractor_unsafe_check();
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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 recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    ractor_unsafe_check();
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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 recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    ractor_unsafe_check();
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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 recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    ractor_unsafe_check();
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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 recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    ractor_unsafe_check();
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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 recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    ractor_unsafe_check();
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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 recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    ractor_unsafe_check();
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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]);
}

static VALUE
ractor_safe_call_cfunc_m2(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    return (*func)(recv, rb_ary_new4(argc, argv));
}

static VALUE
ractor_safe_call_cfunc_m1(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    return (*func)(argc, argv, recv);
}

static VALUE
ractor_safe_call_cfunc_0(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE) = (VALUE(*)(VALUE))func;
    return (*f)(recv);
}

static VALUE
ractor_safe_call_cfunc_1(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE) = (VALUE(*)(VALUE, VALUE))func;
    return (*f)(recv, argv[0]);
}

static VALUE
ractor_safe_call_cfunc_2(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE))func;
    return (*f)(recv, argv[0], argv[1]);
}

static VALUE
ractor_safe_call_cfunc_3(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(recv, argv[0], argv[1], argv[2]);
}

static VALUE
ractor_safe_call_cfunc_4(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(recv, argv[0], argv[1], argv[2], argv[3]);
}

static VALUE
ractor_safe_call_cfunc_5(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(recv, argv[0], argv[1], argv[2], argv[3], argv[4]);
}

static VALUE
ractor_safe_call_cfunc_6(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5]);
}

static VALUE
ractor_safe_call_cfunc_7(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6]);
}

static VALUE
ractor_safe_call_cfunc_8(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7]);
}

static VALUE
ractor_safe_call_cfunc_9(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8]);
}

static VALUE
ractor_safe_call_cfunc_10(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(recv, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8], argv[9]);
}

static VALUE
ractor_safe_call_cfunc_11(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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
ractor_safe_call_cfunc_12(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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
ractor_safe_call_cfunc_13(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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
ractor_safe_call_cfunc_14(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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
ractor_safe_call_cfunc_15(VALUE recv, int argc, const VALUE *argv, VALUE (*func)(ANYARGS))
{
    VALUE(*f)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE) = (VALUE(*)(VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE))func;
    return (*f)(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]);
}

static inline int
vm_cfp_consistent_p(rb_execution_context_t *ec, const rb_control_frame_t *reg_cfp)
{
    const int ov_flags = RAISED_STACKOVERFLOW;
    if (LIKELY(reg_cfp == ec->cfp + 1)) return TRUE;
    if (rb_ec_raised_p(ec, ov_flags)) {
        rb_ec_raised_reset(ec, ov_flags);
        return TRUE;
    }
    return FALSE;
}

#define CHECK_CFP_CONSISTENCY(func) \
    (LIKELY(vm_cfp_consistent_p(ec, reg_cfp)) ? (void)0 : \
     rb_bug(func ": cfp consistency error (%p, %p)", (void *)reg_cfp, (void *)(ec->cfp+1)))

static inline
const rb_method_cfunc_t *
vm_method_cfunc_entry(const rb_callable_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);
        METHOD_BUG(ALIAS);
# undef METHOD_BUG
      default:
        rb_bug("wrong method type: %d", me->def->type);
    }
#endif
    return UNALIGNED_MEMBER_PTR(me->def, body.cfunc);
}

static VALUE
vm_call_cfunc_with_frame(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_cfunc_with_frame);
    const struct rb_callinfo *ci = calling->ci;
    const struct rb_callcache *cc = calling->cc;
    VALUE val;
    const rb_callable_method_entry_t *me = vm_cc_cme(cc);
    const rb_method_cfunc_t *cfunc = vm_method_cfunc_entry(me);
    int len = cfunc->argc;

    VALUE recv = calling->recv;
    VALUE block_handler = calling->block_handler;
    VALUE frame_type = VM_FRAME_MAGIC_CFUNC | VM_FRAME_FLAG_CFRAME | VM_ENV_FLAG_LOCAL;
    int argc = calling->argc;
    int orig_argc = argc;

    if (UNLIKELY(calling->kw_splat)) {
        frame_type |= VM_FRAME_FLAG_CFRAME_KW;
    }

    RUBY_DTRACE_CMETHOD_ENTRY_HOOK(ec, me->owner, me->def->original_id);
    EXEC_EVENT_HOOK(ec, RUBY_EVENT_C_CALL, recv, me->def->original_id, vm_ci_mid(ci), me->owner, Qundef);

    vm_push_frame(ec, NULL, frame_type, recv,
                  block_handler, (VALUE)me,
                  0, ec->cfp->sp, 0, 0);

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

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

    CHECK_CFP_CONSISTENCY("vm_call_cfunc");

    rb_vm_pop_frame(ec);

    EXEC_EVENT_HOOK(ec, RUBY_EVENT_C_RETURN, recv, me->def->original_id, vm_ci_mid(ci), me->owner, val);
    RUBY_DTRACE_CMETHOD_RETURN_HOOK(ec, me->owner, me->def->original_id);

    return val;
}

static VALUE
vm_call_cfunc(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling)
{
    const struct rb_callinfo *ci = calling->ci;
    RB_DEBUG_COUNTER_INC(ccf_cfunc);

    CALLER_SETUP_ARG(reg_cfp, calling, ci);
    CALLER_REMOVE_EMPTY_KW_SPLAT(reg_cfp, calling, ci);
    CC_SET_FASTPATH(calling->cc, vm_call_cfunc_with_frame, !rb_splat_or_kwargs_p(ci) && !calling->kw_splat);
    return vm_call_cfunc_with_frame(ec, reg_cfp, calling);
}

static VALUE
vm_call_ivar(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    const struct rb_callcache *cc = calling->cc;
    RB_DEBUG_COUNTER_INC(ccf_ivar);
    cfp->sp -= 1;
    return vm_getivar(calling->recv, vm_cc_cme(cc)->def->body.attr.id, NULL, NULL, cc, TRUE);
}

static VALUE
vm_call_attrset(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    const struct rb_callcache *cc = calling->cc;
    RB_DEBUG_COUNTER_INC(ccf_attrset);
    VALUE val = *(cfp->sp - 1);
    cfp->sp -= 2;
    return vm_setivar(calling->recv, vm_cc_cme(cc)->def->body.attr.id, val, NULL, NULL, cc, 1);
}

bool
rb_vm_call_ivar_attrset_p(const vm_call_handler ch)
{
    return (ch == vm_call_ivar || ch == vm_call_attrset);
}

static inline VALUE
vm_call_bmethod_body(rb_execution_context_t *ec, struct rb_calling_info *calling, const VALUE *argv)
{
    rb_proc_t *proc;
    VALUE val;
    const struct rb_callcache *cc = calling->cc;
    const rb_callable_method_entry_t *cme = vm_cc_cme(cc);
    VALUE procv = cme->def->body.bmethod.proc;

    if (!RB_OBJ_SHAREABLE_P(procv) &&
        cme->def->body.bmethod.defined_ractor != rb_ractor_self(rb_ec_ractor_ptr(ec))) {
        rb_raise(rb_eRuntimeError, "defined with an un-shareable Proc in a different Ractor");
    }

    /* control block frame */
    GetProcPtr(procv, proc);
    val = rb_vm_invoke_bmethod(ec, proc, calling->recv, calling->argc, argv, calling->kw_splat, calling->block_handler, vm_cc_cme(cc));

    return val;
}

static VALUE
vm_call_bmethod(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_bmethod);

    VALUE *argv;
    int argc;
    const struct rb_callinfo *ci = calling->ci;

    CALLER_SETUP_ARG(cfp, calling, ci);
    argc = calling->argc;
    argv = ALLOCA_N(VALUE, argc);
    MEMCPY(argv, cfp->sp - argc, VALUE, argc);
    cfp->sp += - argc - 1;

    return vm_call_bmethod_body(ec, calling, argv);
}

MJIT_FUNC_EXPORTED VALUE
rb_find_defined_class_by_owner(VALUE current_class, VALUE target_owner)
{
    VALUE klass = current_class;

    /* for prepended Module, then start from cover class */
    if (RB_TYPE_P(klass, T_ICLASS) && FL_TEST(klass, RICLASS_IS_ORIGIN) &&
            RB_TYPE_P(RBASIC_CLASS(klass), T_CLASS)) {
        klass = RBASIC_CLASS(klass);
    }

    while (RTEST(klass)) {
        VALUE owner = RB_TYPE_P(klass, T_ICLASS) ? RBASIC_CLASS(klass) : klass;
        if (owner == target_owner) {
            return klass;
        }
        klass = RCLASS_SUPER(klass);
    }

    return current_class; /* maybe module function */
}

static const rb_callable_method_entry_t *
aliased_callable_method_entry(const rb_callable_method_entry_t *me)
{
    const rb_method_entry_t *orig_me = me->def->body.alias.original_me;
    const rb_callable_method_entry_t *cme;

    if (orig_me->defined_class == 0) {
        VALUE defined_class = rb_find_defined_class_by_owner(me->defined_class, orig_me->owner);
        VM_ASSERT(RB_TYPE_P(orig_me->owner, T_MODULE));
        cme = rb_method_entry_complement_defined_class(orig_me, me->called_id, defined_class);

        if (me->def->alias_count + me->def->complemented_count == 0) {
            RB_OBJ_WRITE(me, &me->def->body.alias.original_me, cme);
        }
        else {
            rb_method_definition_t *def =
                rb_method_definition_create(VM_METHOD_TYPE_ALIAS, me->def->original_id);
            rb_method_definition_set((rb_method_entry_t *)me, def, (void *)cme);
        }
    }
    else {
        cme = (const rb_callable_method_entry_t *)orig_me;
    }

    VM_ASSERT(callable_method_entry_p(cme));
    return cme;
}

const rb_callable_method_entry_t *
rb_aliased_callable_method_entry(const rb_callable_method_entry_t *me)
{
    return aliased_callable_method_entry(me);
}

static VALUE
vm_call_alias(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    calling->cc = &VM_CC_ON_STACK(Qundef,
                                  vm_call_general,
                                  { 0 },
                                  aliased_callable_method_entry(vm_cc_cme(calling->cc)));

    return vm_call_method_each_type(ec, cfp, calling);
}

static enum method_missing_reason
ci_missing_reason(const struct rb_callinfo *ci)
{
    enum method_missing_reason stat = MISSING_NOENTRY;
    if (vm_ci_flag(ci) & VM_CALL_VCALL) stat |= MISSING_VCALL;
    if (vm_ci_flag(ci) & VM_CALL_FCALL) stat |= MISSING_FCALL;
    if (vm_ci_flag(ci) & VM_CALL_SUPER) stat |= MISSING_SUPER;
    return stat;
}

static VALUE vm_call_method_missing(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling);

static VALUE
vm_call_symbol(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
               struct rb_calling_info *calling, const struct rb_callinfo *ci, VALUE symbol, int flags)
{
    ASSUME(calling->argc >= 0);
    /* Also assumes CALLER_SETUP_ARG is already done. */

    enum method_missing_reason missing_reason = MISSING_NOENTRY;
    int argc = calling->argc;
    VALUE recv = calling->recv;
    VALUE klass = CLASS_OF(recv);
    ID mid = rb_check_id(&symbol);
    flags |= VM_CALL_OPT_SEND | (calling->kw_splat ? VM_CALL_KW_SPLAT : 0);

    if (UNLIKELY(! mid)) {
        mid = idMethodMissing;
        missing_reason = ci_missing_reason(ci);
        ec->method_missing_reason = missing_reason;

        /* E.g. when argc == 2
         *
         *   |      |        |      |  TOPN
         *   |      |        +------+
         *   |      |  +---> | arg1 |    0
         *   +------+  |     +------+
         *   | arg1 | -+ +-> | arg0 |    1
         *   +------+    |   +------+
         *   | arg0 | ---+   | sym  |    2
         *   +------+        +------+
         *   | recv |        | recv |    3
         * --+------+--------+------+------
         */
        int i = argc;
        CHECK_VM_STACK_OVERFLOW(reg_cfp, 1);
        INC_SP(1);
        MEMMOVE(&TOPN(i - 1), &TOPN(i), VALUE, i);
        argc = ++calling->argc;

        if (rb_method_basic_definition_p(klass, idMethodMissing)) {
            /* Inadvertent symbol creation shall be forbidden, see [Feature #5112] */
            TOPN(i) = symbol;
            int priv = vm_ci_flag(ci) & (VM_CALL_FCALL | VM_CALL_VCALL);
            const VALUE *argv = STACK_ADDR_FROM_TOP(argc);
            VALUE exc = rb_make_no_method_exception(
                rb_eNoMethodError, 0, recv, argc, argv, priv);

            rb_exc_raise(exc);
        }
        else {
            TOPN(i) = rb_str_intern(symbol);
        }
    }

    calling->ci = &VM_CI_ON_STACK(mid, flags, argc, vm_ci_kwarg(ci));
    calling->cc = &VM_CC_ON_STACK(klass,
                                  vm_call_general,
                                  { .method_missing_reason = missing_reason },
                                  rb_callable_method_entry_with_refinements(klass, mid, NULL));

    if (flags & VM_CALL_FCALL) {
        return vm_call_method(ec, reg_cfp, calling);
    }

    const struct rb_callcache *cc = calling->cc;
    VM_ASSERT(callable_method_entry_p(vm_cc_cme(cc)));

    if (vm_cc_cme(cc) != NULL) {
        switch (METHOD_ENTRY_VISI(vm_cc_cme(cc))) {
          case METHOD_VISI_PUBLIC: /* likely */
            return vm_call_method_each_type(ec, reg_cfp, calling);
          case METHOD_VISI_PRIVATE:
            vm_cc_method_missing_reason_set(cc, MISSING_PRIVATE);
            break;
          case METHOD_VISI_PROTECTED:
            vm_cc_method_missing_reason_set(cc, MISSING_PROTECTED);
            break;
          default:
            VM_UNREACHABLE(vm_call_method);
        }
        return vm_call_method_missing(ec, reg_cfp, calling);
    }

    return vm_call_method_nome(ec, reg_cfp, calling);
}

static VALUE
vm_call_opt_send(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_opt_send);

    int i;
    VALUE sym;

    CALLER_SETUP_ARG(reg_cfp, calling, calling->ci);

    i = calling->argc - 1;

    if (calling->argc == 0) {
        rb_raise(rb_eArgError, "no method name given");
    }
    else {
        sym = TOPN(i);
        /* E.g. when i == 2
         *
         *   |      |        |      |  TOPN
         *   +------+        |      |
         *   | arg1 | ---+   |      |    0
         *   +------+    |   +------+
         *   | arg0 | -+ +-> | arg1 |    1
         *   +------+  |     +------+
         *   | sym  |  +---> | arg0 |    2
         *   +------+        +------+
         *   | recv |        | recv |    3
         * --+------+--------+------+------
         */
        /* shift arguments */
        if (i > 0) {
            MEMMOVE(&TOPN(i), &TOPN(i-1), VALUE, i);
        }
        calling->argc -= 1;
        DEC_SP(1);

        return vm_call_symbol(ec, reg_cfp, calling, calling->ci, sym, VM_CALL_FCALL);
    }
}

static VALUE
vm_call_method_missing_body(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling,
                            const struct rb_callinfo *orig_ci, enum method_missing_reason reason)
{
    RB_DEBUG_COUNTER_INC(ccf_method_missing);

    VALUE *argv = STACK_ADDR_FROM_TOP(calling->argc);
    unsigned int argc;

    CALLER_SETUP_ARG(reg_cfp, calling, orig_ci);
    argc = calling->argc + 1;

    unsigned int flag = VM_CALL_FCALL | VM_CALL_OPT_SEND | (calling->kw_splat ? VM_CALL_KW_SPLAT : 0);
    calling->argc = argc;

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

    ec->method_missing_reason = reason;
    calling->ci = &VM_CI_ON_STACK(idMethodMissing, flag, argc, vm_ci_kwarg(orig_ci));
    calling->cc = &VM_CC_ON_STACK(Qundef, vm_call_general, { 0 },
                                  rb_callable_method_entry_without_refinements(CLASS_OF(calling->recv), idMethodMissing, NULL));
    return vm_call_method(ec, reg_cfp, calling);
}

static VALUE
vm_call_method_missing(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling)
{
    return vm_call_method_missing_body(ec, reg_cfp, calling, calling->ci, vm_cc_cmethod_missing_reason(calling->cc));
}

static const rb_callable_method_entry_t *refined_method_callable_without_refinement(const rb_callable_method_entry_t *me);
static VALUE
vm_call_zsuper(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling, VALUE klass)
{
    klass = RCLASS_SUPER(klass);

    const rb_callable_method_entry_t *cme = klass ? rb_callable_method_entry(klass, vm_ci_mid(calling->ci)) : NULL;
    if (cme == NULL) {
        return vm_call_method_nome(ec, cfp, calling);
    }
    if (cme->def->type == VM_METHOD_TYPE_REFINED &&
        cme->def->body.refined.orig_me) {
        cme = refined_method_callable_without_refinement(cme);
    }

    calling->cc = &VM_CC_ON_STACK(Qundef, vm_call_general, { 0 }, cme);

    return vm_call_method_each_type(ec, cfp, calling);
}

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

PUREFUNC(static rb_control_frame_t * current_method_entry(const rb_execution_context_t *ec, rb_control_frame_t *cfp));
static rb_control_frame_t *
current_method_entry(const rb_execution_context_t *ec, rb_control_frame_t *cfp)
{
    rb_control_frame_t *top_cfp = cfp;

    if (cfp->iseq && ISEQ_BODY(cfp->iseq)->type == ISEQ_TYPE_BLOCK) {
        const rb_iseq_t *local_iseq = ISEQ_BODY(cfp->iseq)->local_iseq;

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

static const rb_callable_method_entry_t *
refined_method_callable_without_refinement(const rb_callable_method_entry_t *me)
{
    const rb_method_entry_t *orig_me = me->def->body.refined.orig_me;
    const rb_callable_method_entry_t *cme;

    if (orig_me->defined_class == 0) {
        cme = NULL;
        rb_notimplement();
    }
    else {
        cme = (const rb_callable_method_entry_t *)orig_me;
    }

    VM_ASSERT(callable_method_entry_p(cme));

    if (UNDEFINED_METHOD_ENTRY_P(cme)) {
        cme = NULL;
    }

    return cme;
}

static const rb_callable_method_entry_t *
search_refined_method(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    ID mid = vm_ci_mid(calling->ci);
    const rb_cref_t *cref = vm_get_cref(cfp->ep);
    const struct rb_callcache * const cc = calling->cc;
    const rb_callable_method_entry_t *cme = vm_cc_cme(cc);

    for (; cref; cref = CREF_NEXT(cref)) {
        const VALUE refinement = find_refinement(CREF_REFINEMENTS(cref), vm_cc_cme(cc)->owner);
        if (NIL_P(refinement)) continue;

        const rb_callable_method_entry_t *const ref_me =
            rb_callable_method_entry(refinement, mid);

        if (ref_me) {
            if (vm_cc_call(cc) == vm_call_super_method) {
                const rb_control_frame_t *top_cfp = current_method_entry(ec, cfp);
                const rb_callable_method_entry_t *top_me = rb_vm_frame_method_entry(top_cfp);
                if (top_me && rb_method_definition_eq(ref_me->def, top_me->def)) {
                    continue;
                }
            }

            if (cme->def->type != VM_METHOD_TYPE_REFINED ||
                cme->def != ref_me->def) {
                cme = ref_me;
            }
            if (ref_me->def->type != VM_METHOD_TYPE_REFINED) {
                return cme;
            }
        }
        else {
            return NULL;
        }
    }

    if (vm_cc_cme(cc)->def->body.refined.orig_me) {
        return refined_method_callable_without_refinement(vm_cc_cme(cc));
    }
    else {
        VALUE klass = RCLASS_SUPER(vm_cc_cme(cc)->defined_class);
        const rb_callable_method_entry_t *cme = klass ? rb_callable_method_entry(klass, mid) : NULL;
        return cme;
    }
}

static VALUE
vm_call_refined(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    struct rb_callcache *ref_cc =  &VM_CC_ON_STACK(Qundef, vm_call_general, { 0 },
                                                   search_refined_method(ec, cfp, calling));

    if (vm_cc_cme(ref_cc)) {
        calling->cc= ref_cc;
        return vm_call_method(ec, cfp, calling);
    }
    else {
        return vm_call_method_nome(ec, cfp, calling);
    }
}

static inline VALUE vm_invoke_block(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling, const struct rb_callinfo *ci, bool is_lambda, VALUE block_handler);

NOINLINE(static VALUE
         vm_invoke_block_opt_call(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
                                  struct rb_calling_info *calling, const struct rb_callinfo *ci, VALUE block_handler));

static VALUE
vm_invoke_block_opt_call(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
                         struct rb_calling_info *calling, const struct rb_callinfo *ci, VALUE block_handler)
{
    int argc = calling->argc;

    /* remove self */
    if (argc > 0) MEMMOVE(&TOPN(argc), &TOPN(argc-1), VALUE, argc);
    DEC_SP(1);

    return vm_invoke_block(ec, reg_cfp, calling, ci, false, block_handler);
}

static VALUE
vm_call_opt_call(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_opt_call);

    const struct rb_callinfo *ci = calling->ci;
    VALUE procval = calling->recv;
    return vm_invoke_block_opt_call(ec, reg_cfp, calling, ci, VM_BH_FROM_PROC(procval));
}

static VALUE
vm_call_opt_block_call(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_opt_block_call);

    VALUE block_handler = VM_ENV_BLOCK_HANDLER(VM_CF_LEP(reg_cfp));
    const struct rb_callinfo *ci = calling->ci;

    if (BASIC_OP_UNREDEFINED_P(BOP_CALL, PROC_REDEFINED_OP_FLAG)) {
        return vm_invoke_block_opt_call(ec, reg_cfp, calling, ci, block_handler);
    }
    else {
        calling->recv = rb_vm_bh_to_procval(ec, block_handler);
        calling->cc = rb_vm_search_method_slowpath(ci, CLASS_OF(calling->recv));
        return vm_call_general(ec, reg_cfp, calling);
    }
}

static VALUE
vm_call_opt_struct_aref0(rb_execution_context_t *ec, struct rb_calling_info *calling)
{
    VALUE recv = calling->recv;

    VM_ASSERT(RB_TYPE_P(recv, T_STRUCT));
    VM_ASSERT(vm_cc_cme(calling->cc)->def->type == VM_METHOD_TYPE_OPTIMIZED);
    VM_ASSERT(vm_cc_cme(calling->cc)->def->body.optimized.type == OPTIMIZED_METHOD_TYPE_STRUCT_AREF);

    const unsigned int off = vm_cc_cme(calling->cc)->def->body.optimized.index;
    return internal_RSTRUCT_GET(recv, off);
}

static VALUE
vm_call_opt_struct_aref(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_opt_struct_aref);

    VALUE ret = vm_call_opt_struct_aref0(ec, calling);
    reg_cfp->sp -= 1;
    return ret;
}

static VALUE
vm_call_opt_struct_aset0(rb_execution_context_t *ec, struct rb_calling_info *calling, VALUE val)
{
    VALUE recv = calling->recv;

    VM_ASSERT(RB_TYPE_P(recv, T_STRUCT));
    VM_ASSERT(vm_cc_cme(calling->cc)->def->type == VM_METHOD_TYPE_OPTIMIZED);
    VM_ASSERT(vm_cc_cme(calling->cc)->def->body.optimized.type == OPTIMIZED_METHOD_TYPE_STRUCT_ASET);

    rb_check_frozen(recv);

    const unsigned int off = vm_cc_cme(calling->cc)->def->body.optimized.index;
    internal_RSTRUCT_SET(recv, off, val);

    return val;
}

static VALUE
vm_call_opt_struct_aset(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_opt_struct_aset);

    VALUE ret = vm_call_opt_struct_aset0(ec, calling, *(reg_cfp->sp - 1));
    reg_cfp->sp -= 2;
    return ret;
}

NOINLINE(static VALUE vm_call_optimized(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling,
                                        const struct rb_callinfo *ci, const struct rb_callcache *cc));

static VALUE
vm_call_optimized(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling,
                  const struct rb_callinfo *ci, const struct rb_callcache *cc)
{
    switch (vm_cc_cme(cc)->def->body.optimized.type) {
      case OPTIMIZED_METHOD_TYPE_SEND:
        CC_SET_FASTPATH(cc, vm_call_opt_send, TRUE);
        return vm_call_opt_send(ec, cfp, calling);
      case OPTIMIZED_METHOD_TYPE_CALL:
        CC_SET_FASTPATH(cc, vm_call_opt_call, TRUE);
        return vm_call_opt_call(ec, cfp, calling);
      case OPTIMIZED_METHOD_TYPE_BLOCK_CALL:
        CC_SET_FASTPATH(cc, vm_call_opt_block_call, TRUE);
        return vm_call_opt_block_call(ec, cfp, calling);
      case OPTIMIZED_METHOD_TYPE_STRUCT_AREF:
        CALLER_SETUP_ARG(cfp, calling, ci);
        CALLER_REMOVE_EMPTY_KW_SPLAT(cfp, calling, ci);
        rb_check_arity(calling->argc, 0, 0);
        CC_SET_FASTPATH(cc, vm_call_opt_struct_aref, (vm_ci_flag(ci) & VM_CALL_ARGS_SIMPLE));
        return vm_call_opt_struct_aref(ec, cfp, calling);

      case OPTIMIZED_METHOD_TYPE_STRUCT_ASET:
        CALLER_SETUP_ARG(cfp, calling, ci);
        CALLER_REMOVE_EMPTY_KW_SPLAT(cfp, calling, ci);
        rb_check_arity(calling->argc, 1, 1);
        CC_SET_FASTPATH(cc, vm_call_opt_struct_aset, (vm_ci_flag(ci) & VM_CALL_ARGS_SIMPLE));
        return vm_call_opt_struct_aset(ec, cfp, calling);
      default:
        rb_bug("vm_call_method: unsupported optimized method type (%d)", vm_cc_cme(cc)->def->body.optimized.type);
    }
}

#define VM_CALL_METHOD_ATTR(var, func, nohook) \
    if (UNLIKELY(ruby_vm_event_flags & (RUBY_EVENT_C_CALL | RUBY_EVENT_C_RETURN))) { \
        EXEC_EVENT_HOOK(ec, RUBY_EVENT_C_CALL, calling->recv, vm_cc_cme(cc)->def->original_id, \
                        vm_ci_mid(ci), vm_cc_cme(cc)->owner, Qundef); \
        var = func; \
        EXEC_EVENT_HOOK(ec, RUBY_EVENT_C_RETURN, calling->recv, vm_cc_cme(cc)->def->original_id, \
                        vm_ci_mid(ci), vm_cc_cme(cc)->owner, (var)); \
    } \
    else { \
        nohook; \
        var = func; \
    }

static VALUE
vm_call_method_each_type(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    const struct rb_callinfo *ci = calling->ci;
    const struct rb_callcache *cc = calling->cc;
    const rb_callable_method_entry_t *cme = vm_cc_cme(cc);
    VALUE v;

    switch (cme->def->type) {
      case VM_METHOD_TYPE_ISEQ:
        CC_SET_FASTPATH(cc, vm_call_iseq_setup, TRUE);
        return vm_call_iseq_setup(ec, cfp, calling);

      case VM_METHOD_TYPE_NOTIMPLEMENTED:
      case VM_METHOD_TYPE_CFUNC:
        CC_SET_FASTPATH(cc, vm_call_cfunc, TRUE);
        return vm_call_cfunc(ec, cfp, calling);

      case VM_METHOD_TYPE_ATTRSET:
        CALLER_SETUP_ARG(cfp, calling, ci);
        CALLER_REMOVE_EMPTY_KW_SPLAT(cfp, calling, ci);

        rb_check_arity(calling->argc, 1, 1);
        vm_cc_attr_index_initialize(cc);
        const unsigned int aset_mask = (VM_CALL_ARGS_SPLAT | VM_CALL_KW_SPLAT | VM_CALL_KWARG);
        VM_CALL_METHOD_ATTR(v,
                            vm_call_attrset(ec, cfp, calling),
                            CC_SET_FASTPATH(cc, vm_call_attrset, !(vm_ci_flag(ci) & aset_mask)));
        return v;

      case VM_METHOD_TYPE_IVAR:
        CALLER_SETUP_ARG(cfp, calling, ci);
        CALLER_REMOVE_EMPTY_KW_SPLAT(cfp, calling, ci);
        rb_check_arity(calling->argc, 0, 0);
        vm_cc_attr_index_initialize(cc);
        const unsigned int ivar_mask = (VM_CALL_ARGS_SPLAT | VM_CALL_KW_SPLAT);
        VM_CALL_METHOD_ATTR(v,
                            vm_call_ivar(ec, cfp, calling),
                            CC_SET_FASTPATH(cc, vm_call_ivar, !(vm_ci_flag(ci) & ivar_mask)));
        return v;

      case VM_METHOD_TYPE_MISSING:
        vm_cc_method_missing_reason_set(cc, 0);
        CC_SET_FASTPATH(cc, vm_call_method_missing, TRUE);
        return vm_call_method_missing(ec, cfp, calling);

      case VM_METHOD_TYPE_BMETHOD:
        CC_SET_FASTPATH(cc, vm_call_bmethod, TRUE);
        return vm_call_bmethod(ec, cfp, calling);

      case VM_METHOD_TYPE_ALIAS:
        CC_SET_FASTPATH(cc, vm_call_alias, TRUE);
        return vm_call_alias(ec, cfp, calling);

      case VM_METHOD_TYPE_OPTIMIZED:
        return vm_call_optimized(ec, cfp, calling, ci, cc);

      case VM_METHOD_TYPE_UNDEF:
        break;

      case VM_METHOD_TYPE_ZSUPER:
        return vm_call_zsuper(ec, cfp, calling, RCLASS_ORIGIN(vm_cc_cme(cc)->defined_class));

      case VM_METHOD_TYPE_REFINED:
        // CC_SET_FASTPATH(cc, vm_call_refined, TRUE);
        // should not set FASTPATH since vm_call_refined assumes cc->call is vm_call_super_method on invokesuper.
        return vm_call_refined(ec, cfp, calling);
    }

    rb_bug("vm_call_method: unsupported method type (%d)", vm_cc_cme(cc)->def->type);
}

NORETURN(static void vm_raise_method_missing(rb_execution_context_t *ec, int argc, const VALUE *argv, VALUE obj, int call_status));

static VALUE
vm_call_method_nome(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    /* method missing */
    const struct rb_callinfo *ci = calling->ci;
    const int stat = ci_missing_reason(ci);

    if (vm_ci_mid(ci) == idMethodMissing) {
        rb_control_frame_t *reg_cfp = cfp;
        VALUE *argv = STACK_ADDR_FROM_TOP(calling->argc);
        vm_raise_method_missing(ec, calling->argc, argv, calling->recv, stat);
    }
    else {
        return vm_call_method_missing_body(ec, cfp, calling, ci, stat);
    }
}

/* Protected method calls and super invocations need to check that the receiver
 * (self for super) inherits the module on which the method is defined.
 * In the case of refinements, it should consider the original class not the
 * refinement.
 */
static VALUE
vm_defined_class_for_protected_call(const rb_callable_method_entry_t *me)
{
    VALUE defined_class = me->defined_class;
    VALUE refined_class = RCLASS_REFINED_CLASS(defined_class);
    return NIL_P(refined_class) ? defined_class : refined_class;
}

static inline VALUE
vm_call_method(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_calling_info *calling)
{
    const struct rb_callinfo *ci = calling->ci;
    const struct rb_callcache *cc = calling->cc;

    VM_ASSERT(callable_method_entry_p(vm_cc_cme(cc)));

    if (vm_cc_cme(cc) != NULL) {
        switch (METHOD_ENTRY_VISI(vm_cc_cme(cc))) {
          case METHOD_VISI_PUBLIC: /* likely */
            return vm_call_method_each_type(ec, cfp, calling);

          case METHOD_VISI_PRIVATE:
            if (!(vm_ci_flag(ci) & VM_CALL_FCALL)) {
                enum method_missing_reason stat = MISSING_PRIVATE;
                if (vm_ci_flag(ci) & VM_CALL_VCALL) stat |= MISSING_VCALL;

                vm_cc_method_missing_reason_set(cc, stat);
                CC_SET_FASTPATH(cc, vm_call_method_missing, TRUE);
                return vm_call_method_missing(ec, cfp, calling);
            }
            return vm_call_method_each_type(ec, cfp, calling);

          case METHOD_VISI_PROTECTED:
            if (!(vm_ci_flag(ci) & (VM_CALL_OPT_SEND | VM_CALL_FCALL))) {
                VALUE defined_class = vm_defined_class_for_protected_call(vm_cc_cme(cc));
                if (!rb_obj_is_kind_of(cfp->self, defined_class)) {
                    vm_cc_method_missing_reason_set(cc, MISSING_PROTECTED);
                    return vm_call_method_missing(ec, cfp, calling);
                }
                else {
                    /* caching method info to dummy cc */
                    VM_ASSERT(vm_cc_cme(cc) != NULL);
                    struct rb_callcache cc_on_stack = *cc;
                    FL_SET_RAW((VALUE)&cc_on_stack, VM_CALLCACHE_UNMARKABLE);
                    calling->cc = &cc_on_stack;
                    return vm_call_method_each_type(ec, cfp, calling);
                }
            }
            return vm_call_method_each_type(ec, cfp, calling);

          default:
            rb_bug("unreachable");
        }
    }
    else {
        return vm_call_method_nome(ec, cfp, calling);
    }
}

static VALUE
vm_call_general(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_general);
    return vm_call_method(ec, reg_cfp, calling);
}

void
rb_vm_cc_general(const struct rb_callcache *cc)
{
    VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
    VM_ASSERT(cc != vm_cc_empty());

    *(vm_call_handler *)&cc->call_ = vm_call_general;
}

static VALUE
vm_call_super_method(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, struct rb_calling_info *calling)
{
    RB_DEBUG_COUNTER_INC(ccf_super_method);

    // This line is introduced to make different from `vm_call_general` because some compilers (VC we found)
    // can merge the function and the address of the function becomes same.
    // The address of `vm_call_super_method` is used in `search_refined_method`, so it should be different.
    if (ec == NULL) rb_bug("unreachable");

    /* this check is required to distinguish with other functions. */
    VM_ASSERT(vm_cc_call(calling->cc) == vm_call_super_method);
    return vm_call_method(ec, reg_cfp, calling);
}

/* super */

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

NORETURN(static void vm_super_outside(void));

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

static const struct rb_callcache *
empty_cc_for_super(void)
{
#ifdef MJIT_HEADER
    return rb_vm_empty_cc_for_super();
#else
    return &vm_empty_cc_for_super;
#endif
}

static const struct rb_callcache *
vm_search_super_method(const rb_control_frame_t *reg_cfp, struct rb_call_data *cd, VALUE recv)
{
    VALUE current_defined_class;
    const rb_callable_method_entry_t *me = rb_vm_frame_method_entry(reg_cfp);

    if (!me) {
        vm_super_outside();
    }

    current_defined_class = vm_defined_class_for_protected_call(me);

    if (BUILTIN_TYPE(current_defined_class) != T_MODULE &&
        reg_cfp->iseq != method_entry_iseqptr(me) &&
        !rb_obj_is_kind_of(recv, current_defined_class)) {
        VALUE m = RB_TYPE_P(current_defined_class, T_ICLASS) ?
            RCLASS_INCLUDER(current_defined_class) : current_defined_class;

        if (m) { /* not bound UnboundMethod */
            rb_raise(rb_eTypeError,
                     "self has wrong type to call super in this context: "
                     "%"PRIsVALUE" (expected %"PRIsVALUE")",
                     rb_obj_class(recv), m);
        }
    }

    if (me->def->type == VM_METHOD_TYPE_BMETHOD && (vm_ci_flag(cd->ci) & VM_CALL_ZSUPER)) {
        rb_raise(rb_eRuntimeError,
                 "implicit argument passing of super from method defined"
                 " by define_method() is not supported."
                 " Specify all arguments explicitly.");
    }

    ID mid = me->def->original_id;

    // update iseq. really? (TODO)
    cd->ci = vm_ci_new_runtime(mid,
                               vm_ci_flag(cd->ci),
                               vm_ci_argc(cd->ci),
                               vm_ci_kwarg(cd->ci));

    RB_OBJ_WRITTEN(reg_cfp->iseq, Qundef, cd->ci);

    const struct rb_callcache *cc;

    VALUE klass = vm_search_normal_superclass(me->defined_class);

    if (!klass) {
        /* bound instance method of module */
        cc = vm_cc_new(klass, NULL, vm_call_method_missing);
        RB_OBJ_WRITE(reg_cfp->iseq, &cd->cc, cc);
    }
    else {
        cc = vm_search_method_fastpath((VALUE)reg_cfp->iseq, cd, klass);
        const rb_callable_method_entry_t *cached_cme = vm_cc_cme(cc);

        // define_method can cache for different method id
        if (cached_cme == NULL) {
            // empty_cc_for_super is not markable object
            cd->cc = empty_cc_for_super();
        }
        else if (cached_cme->called_id != mid) {
            const rb_callable_method_entry_t *cme = rb_callable_method_entry(klass, mid);
            if (cme) {
                cc = vm_cc_new(klass, cme, vm_call_super_method);
                RB_OBJ_WRITE(reg_cfp->iseq, &cd->cc, cc);
            }
            else {
                cd->cc = cc = empty_cc_for_super();
            }
        }
        else {
            switch (cached_cme->def->type) {
              // vm_call_refined (search_refined_method) assumes cc->call is vm_call_super_method on invokesuper
              case VM_METHOD_TYPE_REFINED:
              // cc->klass is superclass of receiver class. Checking cc->klass is not enough to invalidate IVC for the receiver class.
              case VM_METHOD_TYPE_ATTRSET:
              case VM_METHOD_TYPE_IVAR:
                vm_cc_call_set(cc, vm_call_super_method); // invalidate fastpath
                break;
              default:
                break; // use fastpath
            }
        }
    }

    VM_ASSERT((vm_cc_cme(cc), true));

    return cc;
}

/* 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 VALUE
vm_yield_with_cfunc(rb_execution_context_t *ec,
                    const struct rb_captured_block *captured,
                    VALUE self, int argc, const VALUE *argv, int kw_splat, VALUE block_handler,
                    const rb_callable_method_entry_t *me)
{
    int is_lambda = FALSE; /* TODO */
    VALUE val, arg, blockarg;
    int frame_flag;
    const struct vm_ifunc *ifunc = captured->code.ifunc;

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

    blockarg = rb_vm_bh_to_procval(ec, block_handler);

    frame_flag = VM_FRAME_MAGIC_IFUNC | VM_FRAME_FLAG_CFRAME | (me ? VM_FRAME_FLAG_BMETHOD : 0);
    if (kw_splat) {
        frame_flag |= VM_FRAME_FLAG_CFRAME_KW;
    }

    vm_push_frame(ec, (const rb_iseq_t *)captured->code.ifunc,
                  frame_flag,
                  self,
                  VM_GUARDED_PREV_EP(captured->ep),
                  (VALUE)me,
                  0, ec->cfp->sp, 0, 0);
    val = (*ifunc->func)(arg, (VALUE)ifunc->data, argc, argv, blockarg);
    rb_vm_pop_frame(ec);

    return val;
}

static VALUE
vm_yield_with_symbol(rb_execution_context_t *ec,  VALUE symbol, int argc, const VALUE *argv, int kw_splat, VALUE block_handler)
{
    return rb_sym_proc_call(SYM2ID(symbol), argc, argv, kw_splat, rb_vm_bh_to_procval(ec, block_handler));
}

static inline int
vm_callee_setup_block_arg_arg0_splat(rb_control_frame_t *cfp, const rb_iseq_t *iseq, VALUE *argv, VALUE ary)
{
    int i;
    long len = RARRAY_LEN(ary);

    CHECK_VM_STACK_OVERFLOW(cfp, ISEQ_BODY(iseq)->param.lead_num);

    for (i=0; i<len && i<ISEQ_BODY(iseq)->param.lead_num; i++) {
        argv[i] = RARRAY_AREF(ary, i);
    }

    return i;
}

static inline VALUE
vm_callee_setup_block_arg_arg0_check(VALUE *argv)
{
    VALUE ary, arg0 = argv[0];
    ary = rb_check_array_type(arg0);
#if 0
    argv[0] = arg0;
#else
    VM_ASSERT(argv[0] == arg0);
#endif
    return ary;
}

static int
vm_callee_setup_block_arg(rb_execution_context_t *ec, struct rb_calling_info *calling, const struct rb_callinfo *ci, const rb_iseq_t *iseq, VALUE *argv, const enum arg_setup_type arg_setup_type)
{
    if (rb_simple_iseq_p(iseq)) {
        rb_control_frame_t *cfp = ec->cfp;
        VALUE arg0;

        CALLER_SETUP_ARG(cfp, calling, ci);
        CALLER_REMOVE_EMPTY_KW_SPLAT(cfp, calling, ci);

        if (arg_setup_type == arg_setup_block &&
            calling->argc == 1 &&
            ISEQ_BODY(iseq)->param.flags.has_lead &&
            !ISEQ_BODY(iseq)->param.flags.ambiguous_param0 &&
            !NIL_P(arg0 = vm_callee_setup_block_arg_arg0_check(argv))) {
            calling->argc = vm_callee_setup_block_arg_arg0_splat(cfp, iseq, argv, arg0);
        }

        if (calling->argc != ISEQ_BODY(iseq)->param.lead_num) {
            if (arg_setup_type == arg_setup_block) {
                if (calling->argc < ISEQ_BODY(iseq)->param.lead_num) {
                    int i;
                    CHECK_VM_STACK_OVERFLOW(cfp, ISEQ_BODY(iseq)->param.lead_num);
                    for (i=calling->argc; i<ISEQ_BODY(iseq)->param.lead_num; i++) argv[i] = Qnil;
                    calling->argc = ISEQ_BODY(iseq)->param.lead_num; /* fill rest parameters */
                }
                else if (calling->argc > ISEQ_BODY(iseq)->param.lead_num) {
                    calling->argc = ISEQ_BODY(iseq)->param.lead_num; /* simply truncate arguments */
                }
            }
            else {
                argument_arity_error(ec, iseq, calling->argc, ISEQ_BODY(iseq)->param.lead_num, ISEQ_BODY(iseq)->param.lead_num);
            }
        }

        return 0;
    }
    else {
        return setup_parameters_complex(ec, iseq, calling, ci, argv, arg_setup_type);
    }
}

static int
vm_yield_setup_args(rb_execution_context_t *ec, const rb_iseq_t *iseq, const int argc, VALUE *argv, int kw_splat, VALUE block_handler, enum arg_setup_type arg_setup_type)
{
    struct rb_calling_info calling_entry, *calling;

    calling = &calling_entry;
    calling->argc = argc;
    calling->block_handler = block_handler;
    calling->kw_splat = kw_splat;
    calling->recv = Qundef;
    struct rb_callinfo dummy_ci = VM_CI_ON_STACK(0, (kw_splat ? VM_CALL_KW_SPLAT : 0), 0, 0);

    return vm_callee_setup_block_arg(ec, calling, &dummy_ci, iseq, argv, arg_setup_type);
}

/* ruby iseq -> ruby block */

static VALUE
vm_invoke_iseq_block(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
                     struct rb_calling_info *calling, const struct rb_callinfo *ci,
                     bool is_lambda, VALUE block_handler)
{
    const struct rb_captured_block *captured = VM_BH_TO_ISEQ_BLOCK(block_handler);
    const rb_iseq_t *iseq = rb_iseq_check(captured->code.iseq);
    const int arg_size = ISEQ_BODY(iseq)->param.size;
    VALUE * const rsp = GET_SP() - calling->argc;
    int opt_pc = vm_callee_setup_block_arg(ec, calling, ci, iseq, rsp, is_lambda ? arg_setup_method : arg_setup_block);

    SET_SP(rsp);

    vm_push_frame(ec, iseq,
                  VM_FRAME_MAGIC_BLOCK | (is_lambda ? VM_FRAME_FLAG_LAMBDA : 0),
                  captured->self,
                  VM_GUARDED_PREV_EP(captured->ep), 0,
                  ISEQ_BODY(iseq)->iseq_encoded + opt_pc,
                  rsp + arg_size,
                  ISEQ_BODY(iseq)->local_table_size - arg_size, ISEQ_BODY(iseq)->stack_max);

    return Qundef;
}

static VALUE
vm_invoke_symbol_block(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
                       struct rb_calling_info *calling, const struct rb_callinfo *ci,
                       MAYBE_UNUSED(bool is_lambda), VALUE block_handler)
{
    if (calling->argc < 1) {
        rb_raise(rb_eArgError, "no receiver given");
    }
    else {
        VALUE symbol = VM_BH_TO_SYMBOL(block_handler);
        CALLER_SETUP_ARG(reg_cfp, calling, ci);
        calling->recv = TOPN(--calling->argc);
        return vm_call_symbol(ec, reg_cfp, calling, ci, symbol, 0);
    }
}

static VALUE
vm_invoke_ifunc_block(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
                      struct rb_calling_info *calling, const struct rb_callinfo *ci,
                      MAYBE_UNUSED(bool is_lambda), VALUE block_handler)
{
    VALUE val;
    int argc;
    const struct rb_captured_block *captured = VM_BH_TO_IFUNC_BLOCK(block_handler);
    CALLER_SETUP_ARG(ec->cfp, calling, ci);
    CALLER_REMOVE_EMPTY_KW_SPLAT(ec->cfp, calling, ci);
    argc = calling->argc;
    val = vm_yield_with_cfunc(ec, captured, captured->self, argc, STACK_ADDR_FROM_TOP(argc), calling->kw_splat, calling->block_handler, NULL);
    POPN(argc); /* TODO: should put before C/yield? */
    return val;
}

static VALUE
vm_proc_to_block_handler(VALUE procval)
{
    const struct rb_block *block = vm_proc_block(procval);

    switch (vm_block_type(block)) {
      case block_type_iseq:
        return VM_BH_FROM_ISEQ_BLOCK(&block->as.captured);
      case block_type_ifunc:
        return VM_BH_FROM_IFUNC_BLOCK(&block->as.captured);
      case block_type_symbol:
        return VM_BH_FROM_SYMBOL(block->as.symbol);
      case block_type_proc:
        return VM_BH_FROM_PROC(block->as.proc);
    }
    VM_UNREACHABLE(vm_yield_with_proc);
    return Qundef;
}

static VALUE
vm_invoke_proc_block(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
                     struct rb_calling_info *calling, const struct rb_callinfo *ci,
                     bool is_lambda, VALUE block_handler)
{
    while (vm_block_handler_type(block_handler) == block_handler_type_proc) {
        VALUE proc = VM_BH_TO_PROC(block_handler);
        is_lambda = block_proc_is_lambda(proc);
        block_handler = vm_proc_to_block_handler(proc);
    }

    return vm_invoke_block(ec, reg_cfp, calling, ci, is_lambda, block_handler);
}

static inline VALUE
vm_invoke_block(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
                struct rb_calling_info *calling, const struct rb_callinfo *ci,
                bool is_lambda, VALUE block_handler)
{
    VALUE (*func)(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
                  struct rb_calling_info *calling, const struct rb_callinfo *ci,
                  bool is_lambda, VALUE block_handler);

    switch (vm_block_handler_type(block_handler)) {
      case block_handler_type_iseq:   func = vm_invoke_iseq_block;   break;
      case block_handler_type_ifunc:  func = vm_invoke_ifunc_block;  break;
      case block_handler_type_proc:   func = vm_invoke_proc_block;   break;
      case block_handler_type_symbol: func = vm_invoke_symbol_block; break;
      default: rb_bug("vm_invoke_block: unreachable");
    }

    return func(ec, reg_cfp, calling, ci, is_lambda, block_handler);
}

static VALUE
vm_make_proc_with_iseq(const rb_iseq_t *blockiseq)
{
    const rb_execution_context_t *ec = GET_EC();
    const rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(ec, ec->cfp);
    struct rb_captured_block *captured;

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

    captured = VM_CFP_TO_CAPTURED_BLOCK(cfp);
    captured->code.iseq = blockiseq;

    return rb_vm_make_proc(ec, captured, rb_cProc);
}

static VALUE
vm_once_exec(VALUE iseq)
{
    VALUE proc = vm_make_proc_with_iseq((rb_iseq_t *)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;
}

/* defined insn */

static bool
check_respond_to_missing(VALUE obj, VALUE v)
{
    VALUE args[2];
    VALUE r;

    args[0] = obj; args[1] = Qfalse;
    r = rb_check_funcall(v, idRespond_to_missing, 2, args);
    if (r != Qundef && RTEST(r)) {
        return true;
    }
    else {
        return false;
    }
}

static bool
vm_defined(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, rb_num_t op_type, VALUE obj, VALUE v)
{
    VALUE klass;
    enum defined_type type = (enum defined_type)op_type;

    switch (type) {
      case DEFINED_IVAR:
        return rb_ivar_defined(GET_SELF(), SYM2ID(obj));
        break;
      case DEFINED_GVAR:
        return rb_gvar_defined(SYM2ID(obj));
        break;
      case DEFINED_CVAR: {
        const rb_cref_t *cref = vm_get_cref(GET_EP());
        klass = vm_get_cvar_base(cref, GET_CFP(), 0);
        return rb_cvar_defined(klass, SYM2ID(obj));
        break;
      }
      case DEFINED_CONST:
      case DEFINED_CONST_FROM: {
        bool allow_nil = type == DEFINED_CONST;
        klass = v;
        return vm_get_ev_const(ec, klass, SYM2ID(obj), allow_nil, true);
        break;
      }
      case DEFINED_FUNC:
        klass = CLASS_OF(v);
        return rb_ec_obj_respond_to(ec, v, SYM2ID(obj), TRUE);
        break;
      case DEFINED_METHOD:{
        VALUE klass = CLASS_OF(v);
        const rb_method_entry_t *me = rb_method_entry_with_refinements(klass, SYM2ID(obj), NULL);

        if (me) {
            switch (METHOD_ENTRY_VISI(me)) {
              case METHOD_VISI_PRIVATE:
                break;
              case METHOD_VISI_PROTECTED:
                if (!rb_obj_is_kind_of(GET_SELF(), rb_class_real(me->defined_class))) {
                    break;
                }
              case METHOD_VISI_PUBLIC:
                return true;
                break;
              default:
                rb_bug("vm_defined: unreachable: %u", (unsigned int)METHOD_ENTRY_VISI(me));
            }
        }
        else {
            return check_respond_to_missing(obj, v);
        }
        break;
      }
      case DEFINED_YIELD:
        if (GET_BLOCK_HANDLER() != VM_BLOCK_HANDLER_NONE) {
            return true;
        }
        break;
      case DEFINED_ZSUPER:
        {
            const rb_callable_method_entry_t *me = rb_vm_frame_method_entry(GET_CFP());

            if (me) {
                VALUE klass = vm_search_normal_superclass(me->defined_class);
                ID id = me->def->original_id;

                return rb_method_boundp(klass, id, 0);
            }
        }
        break;
      case DEFINED_REF:{
        return vm_getspecial(ec, GET_LEP(), Qfalse, FIX2INT(obj)) != Qnil;
        break;
      }
      default:
        rb_bug("unimplemented defined? type (VM)");
        break;
    }

    return false;
}

bool
rb_vm_defined(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, rb_num_t op_type, VALUE obj, VALUE v)
{
    return vm_defined(ec, reg_cfp, op_type, obj, v);
}

static const VALUE *
vm_get_ep(const VALUE *const reg_ep, rb_num_t lv)
{
    rb_num_t i;
    const VALUE *ep = reg_ep;
    for (i = 0; i < lv; i++) {
        ep = GET_PREV_EP(ep);
    }
    return ep;
}

static VALUE
vm_get_special_object(const VALUE *const reg_ep,
                      enum vm_special_object_type type)
{
    switch (type) {
      case VM_SPECIAL_OBJECT_VMCORE:
        return rb_mRubyVMFrozenCore;
      case VM_SPECIAL_OBJECT_CBASE:
        return vm_get_cbase(reg_ep);
      case VM_SPECIAL_OBJECT_CONST_BASE:
        return vm_get_const_base(reg_ep);
      default:
        rb_bug("putspecialobject insn: unknown value_type %d", type);
    }
}

static VALUE
vm_concat_array(VALUE ary1, VALUE ary2st)
{
    const VALUE ary2 = ary2st;
    VALUE tmp1 = rb_check_to_array(ary1);
    VALUE tmp2 = rb_check_to_array(ary2);

    if (NIL_P(tmp1)) {
        tmp1 = rb_ary_new3(1, ary1);
    }

    if (NIL_P(tmp2)) {
        tmp2 = rb_ary_new3(1, ary2);
    }

    if (tmp1 == ary1) {
        tmp1 = rb_ary_dup(ary1);
    }
    return rb_ary_concat(tmp1, tmp2);
}

// YJIT implementation is using the C function
// and needs to call a non-static function
VALUE
rb_vm_concat_array(VALUE ary1, VALUE ary2st)
{
    return vm_concat_array(ary1, ary2st);
}

static VALUE
vm_splat_array(VALUE flag, VALUE ary)
{
    VALUE tmp = rb_check_to_array(ary);
    if (NIL_P(tmp)) {
        return rb_ary_new3(1, ary);
    }
    else if (RTEST(flag)) {
        return rb_ary_dup(tmp);
    }
    else {
        return tmp;
    }
}

// YJIT implementation is using the C function
// and needs to call a non-static function
VALUE
rb_vm_splat_array(VALUE flag, VALUE ary)
{
    return vm_splat_array(flag, ary);
}

static VALUE
vm_check_match(rb_execution_context_t *ec, VALUE target, VALUE pattern, rb_num_t flag)
{
    enum vm_check_match_type type = ((int)flag) & VM_CHECKMATCH_TYPE_MASK;

    if (flag & VM_CHECKMATCH_ARRAY) {
        long i;
        const long n = RARRAY_LEN(pattern);

        for (i = 0; i < n; i++) {
            VALUE v = RARRAY_AREF(pattern, i);
            VALUE c = check_match(ec, v, target, type);

            if (RTEST(c)) {
                return c;
            }
        }
        return Qfalse;
    }
    else {
        return check_match(ec, pattern, target, type);
    }
}

static VALUE
vm_check_keyword(lindex_t bits, lindex_t idx, const VALUE *ep)
{
    const VALUE kw_bits = *(ep - bits);

    if (FIXNUM_P(kw_bits)) {
        unsigned int b = (unsigned int)FIX2ULONG(kw_bits);
        if ((idx < KW_SPECIFIED_BITS_MAX) && (b & (0x01 << idx)))
            return Qfalse;
    }
    else {
        VM_ASSERT(RB_TYPE_P(kw_bits, T_HASH));
        if (rb_hash_has_key(kw_bits, INT2FIX(idx))) return Qfalse;
    }
    return Qtrue;
}

static void
vm_dtrace(rb_event_flag_t flag, rb_execution_context_t *ec)
{
    if (RUBY_DTRACE_METHOD_ENTRY_ENABLED() ||
        RUBY_DTRACE_METHOD_RETURN_ENABLED() ||
        RUBY_DTRACE_CMETHOD_ENTRY_ENABLED() ||
        RUBY_DTRACE_CMETHOD_RETURN_ENABLED()) {

        switch (flag) {
          case RUBY_EVENT_CALL:
            RUBY_DTRACE_METHOD_ENTRY_HOOK(ec, 0, 0);
            return;
          case RUBY_EVENT_C_CALL:
            RUBY_DTRACE_CMETHOD_ENTRY_HOOK(ec, 0, 0);
            return;
          case RUBY_EVENT_RETURN:
            RUBY_DTRACE_METHOD_RETURN_HOOK(ec, 0, 0);
            return;
          case RUBY_EVENT_C_RETURN:
            RUBY_DTRACE_CMETHOD_RETURN_HOOK(ec, 0, 0);
            return;
        }
    }
}

static VALUE
vm_const_get_under(ID id, rb_num_t flags, VALUE cbase)
{
    if (!rb_const_defined_at(cbase, id)) {
        return 0;
    }
    else if (VM_DEFINECLASS_SCOPED_P(flags)) {
        return rb_public_const_get_at(cbase, id);
    }
    else {
        return rb_const_get_at(cbase, id);
    }
}

static VALUE
vm_check_if_class(ID id, rb_num_t flags, VALUE super, VALUE klass)
{
    if (!RB_TYPE_P(klass, T_CLASS)) {
        return 0;
    }
    else if (VM_DEFINECLASS_HAS_SUPERCLASS_P(flags)) {
        VALUE tmp = rb_class_real(RCLASS_SUPER(klass));

        if (tmp != super) {
            rb_raise(rb_eTypeError,
                     "superclass mismatch for class %"PRIsVALUE"",
                     rb_id2str(id));
        }
        else {
            return klass;
        }
    }
    else {
        return klass;
    }
}

static VALUE
vm_check_if_module(ID id, VALUE mod)
{
    if (!RB_TYPE_P(mod, T_MODULE)) {
        return 0;
    }
    else {
        return mod;
    }
}

static VALUE
declare_under(ID id, VALUE cbase, VALUE c)
{
    rb_set_class_path_string(c, cbase, rb_id2str(id));
    rb_const_set(cbase, id, c);
    return c;
}

static VALUE
vm_declare_class(ID id, rb_num_t flags, VALUE cbase, VALUE super)
{
    /* new class declaration */
    VALUE s = VM_DEFINECLASS_HAS_SUPERCLASS_P(flags) ? super : rb_cObject;
    VALUE c = declare_under(id, cbase, rb_define_class_id(id, s));
    rb_define_alloc_func(c, rb_get_alloc_func(c));
    rb_class_inherited(s, c);
    return c;
}

static VALUE
vm_declare_module(ID id, VALUE cbase)
{
    /* new module declaration */
    return declare_under(id, cbase, rb_module_new());
}

NORETURN(static void unmatched_redefinition(const char *type, VALUE cbase, ID id, VALUE old));
static void
unmatched_redefinition(const char *type, VALUE cbase, ID id, VALUE old)
{
    VALUE name = rb_id2str(id);
    VALUE message = rb_sprintf("%"PRIsVALUE" is not a %s",
                               name, type);
    VALUE location = rb_const_source_location_at(cbase, id);
    if (!NIL_P(location)) {
        rb_str_catf(message, "\n%"PRIsVALUE":%"PRIsVALUE":"
                    " previous definition of %"PRIsVALUE" was here",
                    rb_ary_entry(location, 0), rb_ary_entry(location, 1), name);
    }
    rb_exc_raise(rb_exc_new_str(rb_eTypeError, message));
}

static VALUE
vm_define_class(ID id, rb_num_t flags, VALUE cbase, VALUE super)
{
    VALUE klass;

    if (VM_DEFINECLASS_HAS_SUPERCLASS_P(flags) && !RB_TYPE_P(super, T_CLASS)) {
        rb_raise(rb_eTypeError,
                 "superclass must be an instance of Class (given an instance of %"PRIsVALUE")",
                 rb_obj_class(super));
    }

    vm_check_if_namespace(cbase);

    /* find klass */
    rb_autoload_load(cbase, id);
    if ((klass = vm_const_get_under(id, flags, cbase)) != 0) {
        if (!vm_check_if_class(id, flags, super, klass))
            unmatched_redefinition("class", cbase, id, klass);
        return klass;
    }
    else {
        return vm_declare_class(id, flags, cbase, super);
    }
}

static VALUE
vm_define_module(ID id, rb_num_t flags, VALUE cbase)
{
    VALUE mod;

    vm_check_if_namespace(cbase);
    if ((mod = vm_const_get_under(id, flags, cbase)) != 0) {
        if (!vm_check_if_module(id, mod))
            unmatched_redefinition("module", cbase, id, mod);
        return mod;
    }
    else {
        return vm_declare_module(id, cbase);
    }
}

static VALUE
vm_find_or_create_class_by_id(ID id,
                              rb_num_t flags,
                              VALUE cbase,
                              VALUE super)
{
    rb_vm_defineclass_type_t type = VM_DEFINECLASS_TYPE(flags);

    switch (type) {
      case VM_DEFINECLASS_TYPE_CLASS:
        /* classdef returns class scope value */
        return vm_define_class(id, flags, cbase, super);

      case VM_DEFINECLASS_TYPE_SINGLETON_CLASS:
        /* classdef returns class scope value */
        return rb_singleton_class(cbase);

      case VM_DEFINECLASS_TYPE_MODULE:
        /* classdef returns class scope value */
        return vm_define_module(id, flags, cbase);

      default:
        rb_bug("unknown defineclass type: %d", (int)type);
    }
}

static rb_method_visibility_t
vm_scope_visibility_get(const rb_execution_context_t *ec)
{
    const rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(ec, ec->cfp);

    if (!vm_env_cref_by_cref(cfp->ep)) {
        return METHOD_VISI_PUBLIC;
    }
    else {
        return CREF_SCOPE_VISI(vm_ec_cref(ec))->method_visi;
    }
}

static int
vm_scope_module_func_check(const rb_execution_context_t *ec)
{
    const rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(ec, ec->cfp);

    if (!vm_env_cref_by_cref(cfp->ep)) {
        return FALSE;
    }
    else {
        return CREF_SCOPE_VISI(vm_ec_cref(ec))->module_func;
    }
}

static void
vm_define_method(const rb_execution_context_t *ec, VALUE obj, ID id, VALUE iseqval, int is_singleton)
{
    VALUE klass;
    rb_method_visibility_t visi;
    rb_cref_t *cref = vm_ec_cref(ec);

    if (is_singleton) {
        klass = rb_singleton_class(obj); /* class and frozen checked in this API */
        visi = METHOD_VISI_PUBLIC;
    }
    else {
        klass = CREF_CLASS_FOR_DEFINITION(cref);
        visi = vm_scope_visibility_get(ec);
    }

    if (NIL_P(klass)) {
        rb_raise(rb_eTypeError, "no class/module to add method");
    }

    rb_add_method_iseq(klass, id, (const rb_iseq_t *)iseqval, cref, visi);

    if (!is_singleton && vm_scope_module_func_check(ec)) {
        klass = rb_singleton_class(klass);
        rb_add_method_iseq(klass, id, (const rb_iseq_t *)iseqval, cref, METHOD_VISI_PUBLIC);
    }
}

static VALUE
vm_invokeblock_i(struct rb_execution_context_struct *ec,
                 struct rb_control_frame_struct *reg_cfp,
                 struct rb_calling_info *calling)
{
    const struct rb_callinfo *ci = calling->ci;
    VALUE block_handler = VM_CF_BLOCK_HANDLER(GET_CFP());

    if (block_handler == VM_BLOCK_HANDLER_NONE) {
        rb_vm_localjump_error("no block given (yield)", Qnil, 0);
    }
    else {
        return vm_invoke_block(ec, GET_CFP(), calling, ci, false, block_handler);
    }
}

#ifdef MJIT_HEADER
static const struct rb_callcache *
vm_search_method_wrap(const struct rb_control_frame_struct *reg_cfp, struct rb_call_data *cd, VALUE recv)
{
    return vm_search_method((VALUE)reg_cfp->iseq, cd, recv);
}

static const struct rb_callcache *
vm_search_invokeblock(const struct rb_control_frame_struct *reg_cfp, struct rb_call_data *cd, VALUE recv)
{
    static const struct rb_callcache cc = {
        .flags = T_IMEMO | (imemo_callcache << FL_USHIFT) | VM_CALLCACHE_UNMARKABLE,
        .klass = 0,
        .cme_  = 0,
        .call_ = vm_invokeblock_i,
        .aux_  = {0},
    };
    return &cc;
}

# define mexp_search_method vm_search_method_wrap
# define mexp_search_super vm_search_super_method
# define mexp_search_invokeblock vm_search_invokeblock
#else
enum method_explorer_type {
    mexp_search_method,
    mexp_search_invokeblock,
    mexp_search_super,
};
#endif

static
#ifndef MJIT_HEADER
inline
#endif
VALUE
vm_sendish(
    struct rb_execution_context_struct *ec,
    struct rb_control_frame_struct *reg_cfp,
    struct rb_call_data *cd,
    VALUE block_handler,
#ifdef MJIT_HEADER
    const struct rb_callcache *(*method_explorer)(const struct rb_control_frame_struct *cfp, struct rb_call_data *cd, VALUE recv)
#else
    enum method_explorer_type method_explorer
#endif
) {
    VALUE val = Qundef;
    const struct rb_callinfo *ci = cd->ci;
    const struct rb_callcache *cc;
    int argc = vm_ci_argc(ci);
    VALUE recv = TOPN(argc);
    struct rb_calling_info calling = {
        .block_handler = block_handler,
        .kw_splat = IS_ARGS_KW_SPLAT(ci) > 0,
        .recv = recv,
        .argc = argc,
        .ci = ci,
    };

// The enum-based branch and inlining are faster in VM, but function pointers without inlining are faster in JIT.
#ifdef MJIT_HEADER
    calling.cc = cc = method_explorer(GET_CFP(), cd, recv);
    val = vm_cc_call(cc)(ec, GET_CFP(), &calling);
#else
    switch (method_explorer) {
      case mexp_search_method:
        calling.cc = cc = vm_search_method_fastpath((VALUE)reg_cfp->iseq, cd, CLASS_OF(recv));
        val = vm_cc_call(cc)(ec, GET_CFP(), &calling);
        break;
      case mexp_search_super:
        calling.cc = cc = vm_search_super_method(reg_cfp, cd, recv);
        calling.ci = cd->ci;  // TODO: does it safe?
        val = vm_cc_call(cc)(ec, GET_CFP(), &calling);
        break;
      case mexp_search_invokeblock:
        val = vm_invokeblock_i(ec, GET_CFP(), &calling);
        break;
    }
#endif

    if (val != Qundef) {
        return val;             /* CFUNC normal return */
    }
    else {
        RESTORE_REGS();         /* CFP pushed in cc->call() */
    }

#ifdef MJIT_HEADER
    /* When calling ISeq which may catch an exception from JIT-ed
       code, we should not call jit_exec directly to prevent the
       caller frame from being canceled. That's because the caller
       frame may have stack values in the local variables and the
       cancelling the caller frame will purge them. But directly
       calling jit_exec is faster... */
    if (ISEQ_BODY(GET_ISEQ())->catch_except_p) {
        VM_ENV_FLAGS_SET(GET_EP(), VM_FRAME_FLAG_FINISH);
        return vm_exec(ec, true);
    }
    else if ((val = jit_exec(ec)) == Qundef) {
        VM_ENV_FLAGS_SET(GET_EP(), VM_FRAME_FLAG_FINISH);
        return vm_exec(ec, false);
    }
    else {
        return val;
    }
#else
    /* When calling from VM, longjmp in the callee won't purge any
       JIT-ed caller frames. So it's safe to directly call jit_exec. */
    return jit_exec(ec);
#endif
}

/* object.c */
VALUE rb_nil_to_s(VALUE);
VALUE rb_true_to_s(VALUE);
VALUE rb_false_to_s(VALUE);
/* numeric.c */
VALUE rb_int_to_s(int argc, VALUE *argv, VALUE x);
VALUE rb_fix_to_s(VALUE);
/* variable.c */
VALUE rb_mod_to_s(VALUE);
VALUE rb_mod_name(VALUE);

static VALUE
vm_objtostring(const rb_iseq_t *iseq, VALUE recv, CALL_DATA cd)
{
    int type = TYPE(recv);
    if (type == T_STRING) {
        return recv;
    }

    const struct rb_callcache *cc = vm_search_method((VALUE)iseq, cd, recv);

    switch (type) {
      case T_SYMBOL:
        if (check_cfunc(vm_cc_cme(cc), rb_sym_to_s)) {
            // rb_sym_to_s() allocates a mutable string, but since we are only
            // going to use this string for interpolation, it's fine to use the
            // frozen string.
            return rb_sym2str(recv);
        }
        break;
      case T_MODULE:
      case T_CLASS:
        if (check_cfunc(vm_cc_cme(cc), rb_mod_to_s)) {
            // rb_mod_to_s() allocates a mutable string, but since we are only
            // going to use this string for interpolation, it's fine to use the
            // frozen string.
            VALUE val = rb_mod_name(recv);
            if (NIL_P(val)) {
                val = rb_mod_to_s(recv);
            }
            return val;
        }
        break;
      case T_NIL:
        if (check_cfunc(vm_cc_cme(cc), rb_nil_to_s)) {
            return rb_nil_to_s(recv);
        }
        break;
      case T_TRUE:
        if (check_cfunc(vm_cc_cme(cc), rb_true_to_s)) {
            return rb_true_to_s(recv);
        }
        break;
      case T_FALSE:
        if (check_cfunc(vm_cc_cme(cc), rb_false_to_s)) {
            return rb_false_to_s(recv);
        }
        break;
      case T_FIXNUM:
        if (check_cfunc(vm_cc_cme(cc), rb_int_to_s)) {
            return rb_fix_to_s(recv);
        }
        break;
    }
    return Qundef;
}

static VALUE
vm_opt_str_freeze(VALUE str, int bop, ID id)
{
    if (BASIC_OP_UNREDEFINED_P(bop, STRING_REDEFINED_OP_FLAG)) {
        return str;
    }
    else {
        return Qundef;
    }
}

/* this macro is mandatory to use OPTIMIZED_CMP. What a design! */
#define id_cmp idCmp

static VALUE
vm_opt_newarray_max(rb_execution_context_t *ec, rb_num_t num, const VALUE *ptr)
{
    if (BASIC_OP_UNREDEFINED_P(BOP_MAX, ARRAY_REDEFINED_OP_FLAG)) {
        if (num == 0) {
            return Qnil;
        }
        else {
            struct cmp_opt_data cmp_opt = { 0, 0 };
            VALUE result = *ptr;
            rb_snum_t i = num - 1;
            while (i-- > 0) {
                const VALUE v = *++ptr;
                if (OPTIMIZED_CMP(v, result, cmp_opt) > 0) {
                    result = v;
                }
            }
            return result;
        }
    }
    else {
        return rb_vm_call_with_refinements(ec, rb_ary_new4(num, ptr), idMax, 0, NULL, RB_NO_KEYWORDS);
    }
}

static VALUE
vm_opt_newarray_min(rb_execution_context_t *ec, rb_num_t num, const VALUE *ptr)
{
    if (BASIC_OP_UNREDEFINED_P(BOP_MIN, ARRAY_REDEFINED_OP_FLAG)) {
        if (num == 0) {
            return Qnil;
        }
        else {
            struct cmp_opt_data cmp_opt = { 0, 0 };
            VALUE result = *ptr;
            rb_snum_t i = num - 1;
            while (i-- > 0) {
                const VALUE v = *++ptr;
                if (OPTIMIZED_CMP(v, result, cmp_opt) < 0) {
                    result = v;
                }
            }
            return result;
        }
    }
    else {
        return rb_vm_call_with_refinements(ec, rb_ary_new4(num, ptr), idMin, 0, NULL, RB_NO_KEYWORDS);
    }
}

#undef id_cmp

#define IMEMO_CONST_CACHE_SHAREABLE IMEMO_FL_USER0

static void
vm_track_constant_cache(ID id, void *ic)
{
    struct rb_id_table *const_cache = GET_VM()->constant_cache;
    VALUE lookup_result;
    st_table *ics;

    if (rb_id_table_lookup(const_cache, id, &lookup_result)) {
        ics = (st_table *)lookup_result;
    }
    else {
        ics = st_init_numtable();
        rb_id_table_insert(const_cache, id, (VALUE)ics);
    }

    st_insert(ics, (st_data_t) ic, (st_data_t) Qtrue);
}

static void
vm_ic_track_const_chain(rb_control_frame_t *cfp, IC ic, const ID *segments)
{
    RB_VM_LOCK_ENTER();

    for (int i = 0; segments[i]; i++) {
        ID id = segments[i];
        if (id == idNULL) continue;
        vm_track_constant_cache(id, ic);
    }

    RB_VM_LOCK_LEAVE();
}

// For MJIT inlining
static inline bool
vm_inlined_ic_hit_p(VALUE flags, VALUE value, const rb_cref_t *ic_cref, const VALUE *reg_ep)
{
    if ((flags & IMEMO_CONST_CACHE_SHAREABLE) || rb_ractor_main_p()) {
        VM_ASSERT((flags & IMEMO_CONST_CACHE_SHAREABLE) ? rb_ractor_shareable_p(value) : true);

        return (ic_cref == NULL || // no need to check CREF
                ic_cref == vm_get_cref(reg_ep));
    }
    return false;
}

static bool
vm_ic_hit_p(const struct iseq_inline_constant_cache_entry *ice, const VALUE *reg_ep)
{
    VM_ASSERT(IMEMO_TYPE_P(ice, imemo_constcache));
    return vm_inlined_ic_hit_p(ice->flags, ice->value, ice->ic_cref, reg_ep);
}

// YJIT needs this function to never allocate and never raise
bool
rb_vm_ic_hit_p(IC ic, const VALUE *reg_ep)
{
    return ic->entry && vm_ic_hit_p(ic->entry, reg_ep);
}

static void
vm_ic_update(const rb_iseq_t *iseq, IC ic, VALUE val, const VALUE *reg_ep, const VALUE *pc)
{
    if (ruby_vm_const_missing_count > 0) {
        ruby_vm_const_missing_count = 0;
        ic->entry = NULL;
        return;
    }

    struct iseq_inline_constant_cache_entry *ice = (struct iseq_inline_constant_cache_entry *)rb_imemo_new(imemo_constcache, 0, 0, 0, 0);
    RB_OBJ_WRITE(ice, &ice->value, val);
    ice->ic_cref = vm_get_const_key_cref(reg_ep);
    if (rb_ractor_shareable_p(val)) ice->flags |= IMEMO_CONST_CACHE_SHAREABLE;
    RB_OBJ_WRITE(iseq, &ic->entry, ice);
#ifndef MJIT_HEADER
    // MJIT and YJIT can't be on at the same time, so there is no need to
    // notify YJIT about changes to the IC when running inside MJIT code.
    RUBY_ASSERT(pc >= ISEQ_BODY(iseq)->iseq_encoded);
    unsigned pos = (unsigned)(pc - ISEQ_BODY(iseq)->iseq_encoded);
    rb_yjit_constant_ic_update(iseq, ic, pos);
#endif
}

static VALUE
vm_once_dispatch(rb_execution_context_t *ec, ISEQ iseq, ISE is)
{
    rb_thread_t *th = rb_ec_thread_ptr(ec);
    rb_thread_t *const RUNNING_THREAD_ONCE_DONE = (rb_thread_t *)(0x1);

  again:
    if (is->once.running_thread == RUNNING_THREAD_ONCE_DONE) {
        return is->once.value;
    }
    else if (is->once.running_thread == NULL) {
        VALUE val;
        is->once.running_thread = th;
        val = rb_ensure(vm_once_exec, (VALUE)iseq, vm_once_clear, (VALUE)is);
        RB_OBJ_WRITE(ec->cfp->iseq, &is->once.value, val);
        /* is->once.running_thread is cleared by vm_once_clear() */
        is->once.running_thread = RUNNING_THREAD_ONCE_DONE; /* success */
        return val;
    }
    else if (is->once.running_thread == th) {
        /* recursive once */
        return vm_once_exec((VALUE)iseq);
    }
    else {
        /* waiting for finish */
        RUBY_VM_CHECK_INTS(ec);
        rb_thread_schedule();
        goto again;
    }
}

static OFFSET
vm_case_dispatch(CDHASH hash, OFFSET else_offset, VALUE key)
{
    switch (OBJ_BUILTIN_TYPE(key)) {
      case -1:
      case T_FLOAT:
      case T_SYMBOL:
      case T_BIGNUM:
      case T_STRING:
        if (BASIC_OP_UNREDEFINED_P(BOP_EQQ,
                                   SYMBOL_REDEFINED_OP_FLAG |
                                   INTEGER_REDEFINED_OP_FLAG |
                                   FLOAT_REDEFINED_OP_FLAG |
                                   NIL_REDEFINED_OP_FLAG    |
                                   TRUE_REDEFINED_OP_FLAG   |
                                   FALSE_REDEFINED_OP_FLAG  |
                                   STRING_REDEFINED_OP_FLAG)) {
            st_data_t val;
            if (RB_FLOAT_TYPE_P(key)) {
                double kval = RFLOAT_VALUE(key);
                if (!isinf(kval) && modf(kval, &kval) == 0.0) {
                    key = FIXABLE(kval) ? LONG2FIX((long)kval) : rb_dbl2big(kval);
                }
            }
            if (rb_hash_stlike_lookup(hash, key, &val)) {
                return FIX2LONG((VALUE)val);
            }
            else {
                return else_offset;
            }
        }
    }
    return 0;
}

NORETURN(static void
         vm_stack_consistency_error(const rb_execution_context_t *ec,
                                    const rb_control_frame_t *,
                                    const VALUE *));
static void
vm_stack_consistency_error(const rb_execution_context_t *ec,
                           const rb_control_frame_t *cfp,
                           const VALUE *bp)
{
    const ptrdiff_t nsp = VM_SP_CNT(ec, cfp->sp);
    const ptrdiff_t nbp = VM_SP_CNT(ec, bp);
    static const char stack_consistency_error[] =
        "Stack consistency error (sp: %"PRIdPTRDIFF", bp: %"PRIdPTRDIFF")";
#if defined RUBY_DEVEL
    VALUE mesg = rb_sprintf(stack_consistency_error, nsp, nbp);
    rb_str_cat_cstr(mesg, "\n");
    rb_str_append(mesg, rb_iseq_disasm(cfp->iseq));
    rb_exc_fatal(rb_exc_new3(rb_eFatal, mesg));
#else
    rb_bug(stack_consistency_error, nsp, nbp);
#endif
}

static VALUE
vm_opt_plus(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_PLUS, INTEGER_REDEFINED_OP_FLAG)) {
        return rb_fix_plus_fix(recv, obj);
    }
    else if (FLONUM_2_P(recv, obj) &&
             BASIC_OP_UNREDEFINED_P(BOP_PLUS, FLOAT_REDEFINED_OP_FLAG)) {
        return DBL2NUM(RFLOAT_VALUE(recv) + RFLOAT_VALUE(obj));
    }
    else if (SPECIAL_CONST_P(recv) || SPECIAL_CONST_P(obj)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cFloat &&
             RBASIC_CLASS(obj)  == rb_cFloat &&
             BASIC_OP_UNREDEFINED_P(BOP_PLUS, FLOAT_REDEFINED_OP_FLAG)) {
        return DBL2NUM(RFLOAT_VALUE(recv) + RFLOAT_VALUE(obj));
    }
    else if (RBASIC_CLASS(recv) == rb_cString &&
             RBASIC_CLASS(obj) == rb_cString &&
             BASIC_OP_UNREDEFINED_P(BOP_PLUS, STRING_REDEFINED_OP_FLAG)) {
        return rb_str_opt_plus(recv, obj);
    }
    else if (RBASIC_CLASS(recv) == rb_cArray &&
             RBASIC_CLASS(obj) == rb_cArray &&
             BASIC_OP_UNREDEFINED_P(BOP_PLUS, ARRAY_REDEFINED_OP_FLAG)) {
        return rb_ary_plus(recv, obj);
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_minus(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_MINUS, INTEGER_REDEFINED_OP_FLAG)) {
        return rb_fix_minus_fix(recv, obj);
    }
    else if (FLONUM_2_P(recv, obj) &&
             BASIC_OP_UNREDEFINED_P(BOP_MINUS, FLOAT_REDEFINED_OP_FLAG)) {
        return DBL2NUM(RFLOAT_VALUE(recv) - RFLOAT_VALUE(obj));
    }
    else if (SPECIAL_CONST_P(recv) || SPECIAL_CONST_P(obj)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cFloat &&
             RBASIC_CLASS(obj)  == rb_cFloat &&
             BASIC_OP_UNREDEFINED_P(BOP_MINUS, FLOAT_REDEFINED_OP_FLAG)) {
        return DBL2NUM(RFLOAT_VALUE(recv) - RFLOAT_VALUE(obj));
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_mult(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_MULT, INTEGER_REDEFINED_OP_FLAG)) {
        return rb_fix_mul_fix(recv, obj);
    }
    else if (FLONUM_2_P(recv, obj) &&
             BASIC_OP_UNREDEFINED_P(BOP_MULT, FLOAT_REDEFINED_OP_FLAG)) {
        return DBL2NUM(RFLOAT_VALUE(recv) * RFLOAT_VALUE(obj));
    }
    else if (SPECIAL_CONST_P(recv) || SPECIAL_CONST_P(obj)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cFloat &&
             RBASIC_CLASS(obj)  == rb_cFloat &&
             BASIC_OP_UNREDEFINED_P(BOP_MULT, FLOAT_REDEFINED_OP_FLAG)) {
        return DBL2NUM(RFLOAT_VALUE(recv) * RFLOAT_VALUE(obj));
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_div(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_DIV, INTEGER_REDEFINED_OP_FLAG)) {
        return (FIX2LONG(obj) == 0) ? Qundef : rb_fix_div_fix(recv, obj);
    }
    else if (FLONUM_2_P(recv, obj) &&
             BASIC_OP_UNREDEFINED_P(BOP_DIV, FLOAT_REDEFINED_OP_FLAG)) {
        return rb_flo_div_flo(recv, obj);
    }
    else if (SPECIAL_CONST_P(recv) || SPECIAL_CONST_P(obj)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cFloat &&
             RBASIC_CLASS(obj)  == rb_cFloat &&
             BASIC_OP_UNREDEFINED_P(BOP_DIV, FLOAT_REDEFINED_OP_FLAG)) {
        return rb_flo_div_flo(recv, obj);
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_mod(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_MOD, INTEGER_REDEFINED_OP_FLAG)) {
        return (FIX2LONG(obj) == 0) ? Qundef : rb_fix_mod_fix(recv, obj);
    }
    else if (FLONUM_2_P(recv, obj) &&
             BASIC_OP_UNREDEFINED_P(BOP_MOD, FLOAT_REDEFINED_OP_FLAG)) {
        return DBL2NUM(ruby_float_mod(RFLOAT_VALUE(recv), RFLOAT_VALUE(obj)));
    }
    else if (SPECIAL_CONST_P(recv) || SPECIAL_CONST_P(obj)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cFloat &&
             RBASIC_CLASS(obj)  == rb_cFloat &&
             BASIC_OP_UNREDEFINED_P(BOP_MOD, FLOAT_REDEFINED_OP_FLAG)) {
        return DBL2NUM(ruby_float_mod(RFLOAT_VALUE(recv), RFLOAT_VALUE(obj)));
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_neq(const rb_iseq_t *iseq, CALL_DATA cd, CALL_DATA cd_eq, VALUE recv, VALUE obj)
{
    if (vm_method_cfunc_is(iseq, cd, recv, rb_obj_not_equal)) {
        VALUE val = opt_equality(iseq, recv, obj, cd_eq);

        if (val != Qundef) {
            return RBOOL(!RTEST(val));
        }
    }

    return Qundef;
}

static VALUE
vm_opt_lt(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_LT, INTEGER_REDEFINED_OP_FLAG)) {
        return RBOOL((SIGNED_VALUE)recv < (SIGNED_VALUE)obj);
    }
    else if (FLONUM_2_P(recv, obj) &&
             BASIC_OP_UNREDEFINED_P(BOP_LT, FLOAT_REDEFINED_OP_FLAG)) {
        return RBOOL(RFLOAT_VALUE(recv) < RFLOAT_VALUE(obj));
    }
    else if (SPECIAL_CONST_P(recv) || SPECIAL_CONST_P(obj)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cFloat &&
             RBASIC_CLASS(obj)  == rb_cFloat &&
             BASIC_OP_UNREDEFINED_P(BOP_LT, FLOAT_REDEFINED_OP_FLAG)) {
        CHECK_CMP_NAN(RFLOAT_VALUE(recv), RFLOAT_VALUE(obj));
        return RBOOL(RFLOAT_VALUE(recv) < RFLOAT_VALUE(obj));
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_le(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_LE, INTEGER_REDEFINED_OP_FLAG)) {
        return RBOOL((SIGNED_VALUE)recv <= (SIGNED_VALUE)obj);
    }
    else if (FLONUM_2_P(recv, obj) &&
             BASIC_OP_UNREDEFINED_P(BOP_LE, FLOAT_REDEFINED_OP_FLAG)) {
        return RBOOL(RFLOAT_VALUE(recv) <= RFLOAT_VALUE(obj));
    }
    else if (SPECIAL_CONST_P(recv) || SPECIAL_CONST_P(obj)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cFloat &&
             RBASIC_CLASS(obj)  == rb_cFloat &&
             BASIC_OP_UNREDEFINED_P(BOP_LE, FLOAT_REDEFINED_OP_FLAG)) {
        CHECK_CMP_NAN(RFLOAT_VALUE(recv), RFLOAT_VALUE(obj));
        return RBOOL(RFLOAT_VALUE(recv) <= RFLOAT_VALUE(obj));
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_gt(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_GT, INTEGER_REDEFINED_OP_FLAG)) {
        return RBOOL((SIGNED_VALUE)recv > (SIGNED_VALUE)obj);
    }
    else if (FLONUM_2_P(recv, obj) &&
             BASIC_OP_UNREDEFINED_P(BOP_GT, FLOAT_REDEFINED_OP_FLAG)) {
        return RBOOL(RFLOAT_VALUE(recv) > RFLOAT_VALUE(obj));
    }
    else if (SPECIAL_CONST_P(recv) || SPECIAL_CONST_P(obj)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cFloat &&
             RBASIC_CLASS(obj)  == rb_cFloat &&
             BASIC_OP_UNREDEFINED_P(BOP_GT, FLOAT_REDEFINED_OP_FLAG)) {
        CHECK_CMP_NAN(RFLOAT_VALUE(recv), RFLOAT_VALUE(obj));
        return RBOOL(RFLOAT_VALUE(recv) > RFLOAT_VALUE(obj));
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_ge(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_GE, INTEGER_REDEFINED_OP_FLAG)) {
        return RBOOL((SIGNED_VALUE)recv >= (SIGNED_VALUE)obj);
    }
    else if (FLONUM_2_P(recv, obj) &&
             BASIC_OP_UNREDEFINED_P(BOP_GE, FLOAT_REDEFINED_OP_FLAG)) {
        return RBOOL(RFLOAT_VALUE(recv) >= RFLOAT_VALUE(obj));
    }
    else if (SPECIAL_CONST_P(recv) || SPECIAL_CONST_P(obj)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cFloat &&
             RBASIC_CLASS(obj)  == rb_cFloat &&
             BASIC_OP_UNREDEFINED_P(BOP_GE, FLOAT_REDEFINED_OP_FLAG)) {
        CHECK_CMP_NAN(RFLOAT_VALUE(recv), RFLOAT_VALUE(obj));
        return RBOOL(RFLOAT_VALUE(recv) >= RFLOAT_VALUE(obj));
    }
    else {
        return Qundef;
    }
}


static VALUE
vm_opt_ltlt(VALUE recv, VALUE obj)
{
    if (SPECIAL_CONST_P(recv)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cString &&
             BASIC_OP_UNREDEFINED_P(BOP_LTLT, STRING_REDEFINED_OP_FLAG)) {
        if (LIKELY(RB_TYPE_P(obj, T_STRING))) {
            return rb_str_buf_append(recv, obj);
        }
        else {
            return rb_str_concat(recv, obj);
        }
    }
    else if (RBASIC_CLASS(recv) == rb_cArray &&
             BASIC_OP_UNREDEFINED_P(BOP_LTLT, ARRAY_REDEFINED_OP_FLAG)) {
        return rb_ary_push(recv, obj);
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_and(VALUE recv, VALUE obj)
{
    // If recv and obj are both fixnums, then the bottom tag bit
    // will be 1 on both.  1 & 1 == 1, so the result value will also
    // be a fixnum.  If either side is *not* a fixnum, then the tag bit
    // will be 0, and we return Qundef.
    VALUE ret = ((SIGNED_VALUE) recv) & ((SIGNED_VALUE) obj);

    if (FIXNUM_P(ret) &&
        BASIC_OP_UNREDEFINED_P(BOP_AND, INTEGER_REDEFINED_OP_FLAG)) {
        return ret;
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_or(VALUE recv, VALUE obj)
{
    if (FIXNUM_2_P(recv, obj) &&
        BASIC_OP_UNREDEFINED_P(BOP_OR, INTEGER_REDEFINED_OP_FLAG)) {
        return recv | obj;
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_aref(VALUE recv, VALUE obj)
{
    if (SPECIAL_CONST_P(recv)) {
        if (FIXNUM_2_P(recv, obj) &&
                BASIC_OP_UNREDEFINED_P(BOP_AREF, INTEGER_REDEFINED_OP_FLAG)) {
            return rb_fix_aref(recv, obj);
        }
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cArray &&
             BASIC_OP_UNREDEFINED_P(BOP_AREF, ARRAY_REDEFINED_OP_FLAG)) {
        if (FIXNUM_P(obj)) {
            return rb_ary_entry_internal(recv, FIX2LONG(obj));
        }
        else {
            return rb_ary_aref1(recv, obj);
        }
    }
    else if (RBASIC_CLASS(recv) == rb_cHash &&
             BASIC_OP_UNREDEFINED_P(BOP_AREF, HASH_REDEFINED_OP_FLAG)) {
        return rb_hash_aref(recv, obj);
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_aset(VALUE recv, VALUE obj, VALUE set)
{
    if (SPECIAL_CONST_P(recv)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cArray &&
             BASIC_OP_UNREDEFINED_P(BOP_ASET, ARRAY_REDEFINED_OP_FLAG) &&
             FIXNUM_P(obj)) {
        rb_ary_store(recv, FIX2LONG(obj), set);
        return set;
    }
    else if (RBASIC_CLASS(recv) == rb_cHash &&
             BASIC_OP_UNREDEFINED_P(BOP_ASET, HASH_REDEFINED_OP_FLAG)) {
        rb_hash_aset(recv, obj, set);
        return set;
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_aref_with(VALUE recv, VALUE key)
{
    if (!SPECIAL_CONST_P(recv) && RBASIC_CLASS(recv) == rb_cHash &&
        BASIC_OP_UNREDEFINED_P(BOP_AREF, HASH_REDEFINED_OP_FLAG) &&
        rb_hash_compare_by_id_p(recv) == Qfalse &&
        !FL_TEST(recv, RHASH_PROC_DEFAULT)) {
        return rb_hash_aref(recv, key);
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_aset_with(VALUE recv, VALUE key, VALUE val)
{
    if (!SPECIAL_CONST_P(recv) && RBASIC_CLASS(recv) == rb_cHash &&
        BASIC_OP_UNREDEFINED_P(BOP_ASET, HASH_REDEFINED_OP_FLAG) &&
        rb_hash_compare_by_id_p(recv) == Qfalse) {
        return rb_hash_aset(recv, key, val);
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_length(VALUE recv, int bop)
{
    if (SPECIAL_CONST_P(recv)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cString &&
             BASIC_OP_UNREDEFINED_P(bop, STRING_REDEFINED_OP_FLAG)) {
        if (bop == BOP_EMPTY_P) {
            return LONG2NUM(RSTRING_LEN(recv));
        }
        else {
            return rb_str_length(recv);
        }
    }
    else if (RBASIC_CLASS(recv) == rb_cArray &&
             BASIC_OP_UNREDEFINED_P(bop, ARRAY_REDEFINED_OP_FLAG)) {
        return LONG2NUM(RARRAY_LEN(recv));
    }
    else if (RBASIC_CLASS(recv) == rb_cHash &&
             BASIC_OP_UNREDEFINED_P(bop, HASH_REDEFINED_OP_FLAG)) {
        return INT2FIX(RHASH_SIZE(recv));
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_empty_p(VALUE recv)
{
    switch (vm_opt_length(recv, BOP_EMPTY_P)) {
      case Qundef: return Qundef;
      case INT2FIX(0): return Qtrue;
      default: return Qfalse;
    }
}

VALUE rb_false(VALUE obj);

static VALUE
vm_opt_nil_p(const rb_iseq_t *iseq, CALL_DATA cd, VALUE recv)
{
    if (NIL_P(recv) &&
        BASIC_OP_UNREDEFINED_P(BOP_NIL_P, NIL_REDEFINED_OP_FLAG)) {
        return Qtrue;
    }
    else if (vm_method_cfunc_is(iseq, cd, recv, rb_false)) {
        return Qfalse;
    }
    else {
        return Qundef;
    }
}

static VALUE
fix_succ(VALUE x)
{
    switch (x) {
      case ~0UL:
        /* 0xFFFF_FFFF == INT2FIX(-1)
         * `-1.succ` is of course 0. */
        return INT2FIX(0);
      case RSHIFT(~0UL, 1):
        /* 0x7FFF_FFFF == LONG2FIX(0x3FFF_FFFF)
         * 0x3FFF_FFFF + 1 == 0x4000_0000, which is a Bignum. */
        return rb_uint2big(1UL << (SIZEOF_LONG * CHAR_BIT - 2));
      default:
        /*    LONG2FIX(FIX2LONG(x)+FIX2LONG(y))
         * == ((lx*2+1)/2 + (ly*2+1)/2)*2+1
         * == lx*2 + ly*2 + 1
         * == (lx*2+1) + (ly*2+1) - 1
         * == x + y - 1
         *
         * Here, if we put y := INT2FIX(1):
         *
         * == x + INT2FIX(1) - 1
         * == x + 2 .
         */
        return x + 2;
    }
}

static VALUE
vm_opt_succ(VALUE recv)
{
    if (FIXNUM_P(recv) &&
        BASIC_OP_UNREDEFINED_P(BOP_SUCC, INTEGER_REDEFINED_OP_FLAG)) {
        return fix_succ(recv);
    }
    else if (SPECIAL_CONST_P(recv)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cString &&
             BASIC_OP_UNREDEFINED_P(BOP_SUCC, STRING_REDEFINED_OP_FLAG)) {
        return rb_str_succ(recv);
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_not(const rb_iseq_t *iseq, CALL_DATA cd, VALUE recv)
{
    if (vm_method_cfunc_is(iseq, cd, recv, rb_obj_not)) {
        return RBOOL(!RTEST(recv));
    }
    else {
        return Qundef;
    }
}

static VALUE
vm_opt_regexpmatch2(VALUE recv, VALUE obj)
{
    if (SPECIAL_CONST_P(recv)) {
        return Qundef;
    }
    else if (RBASIC_CLASS(recv) == rb_cString &&
        CLASS_OF(obj) == rb_cRegexp &&
        BASIC_OP_UNREDEFINED_P(BOP_MATCH, STRING_REDEFINED_OP_FLAG)) {
        return rb_reg_match(obj, recv);
    }
    else if (RBASIC_CLASS(recv) == rb_cRegexp &&
        BASIC_OP_UNREDEFINED_P(BOP_MATCH, REGEXP_REDEFINED_OP_FLAG)) {
        return rb_reg_match(recv, obj);
    }
    else {
        return Qundef;
    }
}

rb_event_flag_t rb_iseq_event_flags(const rb_iseq_t *iseq, size_t pos);

NOINLINE(static void vm_trace(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp));

static inline void
vm_trace_hook(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, const VALUE *pc,
              rb_event_flag_t pc_events, rb_event_flag_t target_event,
              rb_hook_list_t *global_hooks, rb_hook_list_t *const *local_hooks_ptr, VALUE val)
{
    rb_event_flag_t event = pc_events & target_event;
    VALUE self = GET_SELF();

    VM_ASSERT(rb_popcount64((uint64_t)event) == 1);

    if (event & global_hooks->events) {
        /* increment PC because source line is calculated with PC-1 */
        reg_cfp->pc++;
        vm_dtrace(event, ec);
        rb_exec_event_hook_orig(ec, global_hooks, event, self, 0, 0, 0 , val, 0);
        reg_cfp->pc--;
    }

    // Load here since global hook above can add and free local hooks
    rb_hook_list_t *local_hooks = *local_hooks_ptr;
    if (local_hooks != NULL) {
        if (event & local_hooks->events) {
            /* increment PC because source line is calculated with PC-1 */
            reg_cfp->pc++;
            rb_exec_event_hook_orig(ec, local_hooks, event, self, 0, 0, 0 , val, 0);
            reg_cfp->pc--;
        }
    }
}

// Return true if given cc has cfunc which is NOT handled by opt_send_without_block.
bool
rb_vm_opt_cfunc_p(CALL_CACHE cc, int insn)
{
    switch (insn) {
      case BIN(opt_eq):
        return check_cfunc(vm_cc_cme(cc), rb_obj_equal);
      case BIN(opt_nil_p):
        return check_cfunc(vm_cc_cme(cc), rb_false);
      case BIN(opt_not):
        return check_cfunc(vm_cc_cme(cc), rb_obj_not);
      default:
        return false;
    }
}

#define VM_TRACE_HOOK(target_event, val) do { \
    if ((pc_events & (target_event)) & enabled_flags) { \
        vm_trace_hook(ec, reg_cfp, pc, pc_events, (target_event), global_hooks, local_hooks_ptr, (val)); \
    } \
} while (0)

static void
vm_trace(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp)
{
    const VALUE *pc = reg_cfp->pc;
    rb_event_flag_t enabled_flags = ruby_vm_event_flags & ISEQ_TRACE_EVENTS;
    rb_event_flag_t global_events = enabled_flags;

    if (enabled_flags == 0 && ruby_vm_event_local_num == 0) {
        return;
    }
    else {
        const rb_iseq_t *iseq = reg_cfp->iseq;
        VALUE iseq_val = (VALUE)iseq;
        size_t pos = pc - ISEQ_BODY(iseq)->iseq_encoded;
        rb_event_flag_t pc_events = rb_iseq_event_flags(iseq, pos);
        rb_hook_list_t *local_hooks = iseq->aux.exec.local_hooks;
        rb_hook_list_t *const *local_hooks_ptr = &iseq->aux.exec.local_hooks;
        rb_event_flag_t iseq_local_events = local_hooks != NULL ? local_hooks->events : 0;
        rb_hook_list_t *bmethod_local_hooks = NULL;
        rb_hook_list_t **bmethod_local_hooks_ptr = NULL;
        rb_event_flag_t bmethod_local_events = 0;
        const bool bmethod_frame = VM_FRAME_BMETHOD_P(reg_cfp);
        enabled_flags |= iseq_local_events;

        VM_ASSERT((iseq_local_events & ~ISEQ_TRACE_EVENTS) == 0);

        if (bmethod_frame) {
            const rb_callable_method_entry_t *me = rb_vm_frame_method_entry(reg_cfp);
            VM_ASSERT(me->def->type == VM_METHOD_TYPE_BMETHOD);
            bmethod_local_hooks = me->def->body.bmethod.hooks;
            bmethod_local_hooks_ptr = &me->def->body.bmethod.hooks;
            if (bmethod_local_hooks) {
                bmethod_local_events = bmethod_local_hooks->events;
            }
        }


        if ((pc_events & enabled_flags) == 0 && !bmethod_frame) {
#if 0
            /* disable trace */
            /* TODO: incomplete */
            rb_iseq_trace_set(iseq, vm_event_flags & ISEQ_TRACE_EVENTS);
#else
            /* do not disable trace because of performance problem
             * (re-enable overhead)
             */
#endif
            return;
        }
        else if (ec->trace_arg != NULL) {
            /* already tracing */
            return;
        }
        else {
            rb_hook_list_t *global_hooks = rb_ec_ractor_hooks(ec);
            /* Note, not considering iseq local events here since the same
             * iseq could be used in multiple bmethods. */
            rb_event_flag_t bmethod_events = global_events | bmethod_local_events;

            if (0) {
                ruby_debug_printf("vm_trace>>%4d (%4x) - %s:%d %s\n",
                                  (int)pos,
                                  (int)pc_events,
                                  RSTRING_PTR(rb_iseq_path(iseq)),
                                  (int)rb_iseq_line_no(iseq, pos),
                                  RSTRING_PTR(rb_iseq_label(iseq)));
            }
            VM_ASSERT(reg_cfp->pc == pc);
            VM_ASSERT(pc_events != 0);

            /* check traces */
            if ((pc_events & RUBY_EVENT_B_CALL) && bmethod_frame && (bmethod_events & RUBY_EVENT_CALL)) {
                /* b_call instruction running as a method. Fire call event. */
                vm_trace_hook(ec, reg_cfp, pc, RUBY_EVENT_CALL, RUBY_EVENT_CALL, global_hooks, bmethod_local_hooks_ptr, Qundef);
            }
            VM_TRACE_HOOK(RUBY_EVENT_CLASS | RUBY_EVENT_CALL | RUBY_EVENT_B_CALL,   Qundef);
            VM_TRACE_HOOK(RUBY_EVENT_LINE,                                          Qundef);
            VM_TRACE_HOOK(RUBY_EVENT_COVERAGE_LINE,                                 Qundef);
            VM_TRACE_HOOK(RUBY_EVENT_COVERAGE_BRANCH,                               Qundef);
            VM_TRACE_HOOK(RUBY_EVENT_END | RUBY_EVENT_RETURN | RUBY_EVENT_B_RETURN, TOPN(0));
            if ((pc_events & RUBY_EVENT_B_RETURN) && bmethod_frame && (bmethod_events & RUBY_EVENT_RETURN)) {
                /* b_return instruction running as a method. Fire return event. */
                vm_trace_hook(ec, reg_cfp, pc, RUBY_EVENT_RETURN, RUBY_EVENT_RETURN, global_hooks, bmethod_local_hooks_ptr, TOPN(0));
            }

            // Pin the iseq since `local_hooks_ptr` points inside the iseq's slot on the GC heap.
            // We need the pointer to stay valid in case compaction happens in a trace hook.
            //
            // Similar treatment is unnecessary for `bmethod_local_hooks_ptr` since
            // storage for `rb_method_definition_t` is not on the GC heap.
            RB_GC_GUARD(iseq_val);
        }
    }
}
#undef VM_TRACE_HOOK

#if VM_CHECK_MODE > 0
NORETURN( NOINLINE( COLDFUNC
void rb_vm_canary_is_found_dead(enum ruby_vminsn_type i, VALUE c)));

void
Init_vm_stack_canary(void)
{
    /* This has to be called _after_ our PRNG is properly set up. */
    int n = ruby_fill_random_bytes(&vm_stack_canary, sizeof vm_stack_canary, false);
    vm_stack_canary |= 0x01; // valid VALUE (Fixnum)

    vm_stack_canary_was_born = true;
    VM_ASSERT(n == 0);
}

#ifndef MJIT_HEADER
MJIT_FUNC_EXPORTED void
rb_vm_canary_is_found_dead(enum ruby_vminsn_type i, VALUE c)
{
    /* Because a method has already been called, why not call
     * another one. */
    const char *insn = rb_insns_name(i);
    VALUE inspection = rb_inspect(c);
    const char *str  = StringValueCStr(inspection);

    rb_bug("dead canary found at %s: %s", insn, str);
}
#endif

#else
void Init_vm_stack_canary(void) { /* nothing to do */ }
#endif


/* a part of the following code is generated by this ruby script:

16.times{|i|
  typedef_args = (0...i).map{|j| "VALUE v#{j+1}"}.join(", ")
  typedef_args.prepend(", ") if i != 0
  call_args = (0...i).map{|j| "argv[#{j}]"}.join(", ")
  call_args.prepend(", ") if i != 0
  puts %Q{
static VALUE
builtin_invoker#{i}(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr#{i}_t)(rb_execution_context_t *ec, VALUE self#{typedef_args});
    return (*(rb_invoke_funcptr#{i}_t)funcptr)(ec, self#{call_args});
}}
}

puts
puts "static VALUE (* const cfunc_invokers[])(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr) = {"
16.times{|i|
  puts "    builtin_invoker#{i},"
}
puts "};"
*/

static VALUE
builtin_invoker0(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr0_t)(rb_execution_context_t *ec, VALUE self);
    return (*(rb_invoke_funcptr0_t)funcptr)(ec, self);
}

static VALUE
builtin_invoker1(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr1_t)(rb_execution_context_t *ec, VALUE self, VALUE v1);
    return (*(rb_invoke_funcptr1_t)funcptr)(ec, self, argv[0]);
}

static VALUE
builtin_invoker2(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr2_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2);
    return (*(rb_invoke_funcptr2_t)funcptr)(ec, self, argv[0], argv[1]);
}

static VALUE
builtin_invoker3(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr3_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3);
    return (*(rb_invoke_funcptr3_t)funcptr)(ec, self, argv[0], argv[1], argv[2]);
}

static VALUE
builtin_invoker4(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr4_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4);
    return (*(rb_invoke_funcptr4_t)funcptr)(ec, self, argv[0], argv[1], argv[2], argv[3]);
}

static VALUE
builtin_invoker5(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr5_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5);
    return (*(rb_invoke_funcptr5_t)funcptr)(ec, self, argv[0], argv[1], argv[2], argv[3], argv[4]);
}

static VALUE
builtin_invoker6(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr6_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5, VALUE v6);
    return (*(rb_invoke_funcptr6_t)funcptr)(ec, self, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5]);
}

static VALUE
builtin_invoker7(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr7_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5, VALUE v6, VALUE v7);
    return (*(rb_invoke_funcptr7_t)funcptr)(ec, self, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6]);
}

static VALUE
builtin_invoker8(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr8_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5, VALUE v6, VALUE v7, VALUE v8);
    return (*(rb_invoke_funcptr8_t)funcptr)(ec, self, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7]);
}

static VALUE
builtin_invoker9(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr9_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5, VALUE v6, VALUE v7, VALUE v8, VALUE v9);
    return (*(rb_invoke_funcptr9_t)funcptr)(ec, self, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8]);
}

static VALUE
builtin_invoker10(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr10_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5, VALUE v6, VALUE v7, VALUE v8, VALUE v9, VALUE v10);
    return (*(rb_invoke_funcptr10_t)funcptr)(ec, self, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8], argv[9]);
}

static VALUE
builtin_invoker11(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr11_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5, VALUE v6, VALUE v7, VALUE v8, VALUE v9, VALUE v10, VALUE v11);
    return (*(rb_invoke_funcptr11_t)funcptr)(ec, self, argv[0], argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], argv[7], argv[8], argv[9], argv[10]);
}

static VALUE
builtin_invoker12(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr12_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5, VALUE v6, VALUE v7, VALUE v8, VALUE v9, VALUE v10, VALUE v11, VALUE v12);
    return (*(rb_invoke_funcptr12_t)funcptr)(ec, self, 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
builtin_invoker13(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr13_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5, VALUE v6, VALUE v7, VALUE v8, VALUE v9, VALUE v10, VALUE v11, VALUE v12, VALUE v13);
    return (*(rb_invoke_funcptr13_t)funcptr)(ec, self, 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
builtin_invoker14(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr14_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5, VALUE v6, VALUE v7, VALUE v8, VALUE v9, VALUE v10, VALUE v11, VALUE v12, VALUE v13, VALUE v14);
    return (*(rb_invoke_funcptr14_t)funcptr)(ec, self, 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
builtin_invoker15(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr)
{
    typedef VALUE (*rb_invoke_funcptr15_t)(rb_execution_context_t *ec, VALUE self, VALUE v1, VALUE v2, VALUE v3, VALUE v4, VALUE v5, VALUE v6, VALUE v7, VALUE v8, VALUE v9, VALUE v10, VALUE v11, VALUE v12, VALUE v13, VALUE v14, VALUE v15);
    return (*(rb_invoke_funcptr15_t)funcptr)(ec, self, 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]);
}

typedef VALUE (*builtin_invoker)(rb_execution_context_t *ec, VALUE self, const VALUE *argv, rb_insn_func_t funcptr);

static builtin_invoker
lookup_builtin_invoker(int argc)
{
    static const builtin_invoker invokers[] = {
        builtin_invoker0,
        builtin_invoker1,
        builtin_invoker2,
        builtin_invoker3,
        builtin_invoker4,
        builtin_invoker5,
        builtin_invoker6,
        builtin_invoker7,
        builtin_invoker8,
        builtin_invoker9,
        builtin_invoker10,
        builtin_invoker11,
        builtin_invoker12,
        builtin_invoker13,
        builtin_invoker14,
        builtin_invoker15,
    };

    return invokers[argc];
}

static inline VALUE
invoke_bf(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, const struct rb_builtin_function* bf, const VALUE *argv)
{
    const bool canary_p = ISEQ_BODY(reg_cfp->iseq)->builtin_inline_p; // Verify an assumption of `Primitive.attr! 'inline'`
    SETUP_CANARY(canary_p);
    VALUE ret = (*lookup_builtin_invoker(bf->argc))(ec, reg_cfp->self, argv, (rb_insn_func_t)bf->func_ptr);
    CHECK_CANARY(canary_p, BIN(invokebuiltin));
    return ret;
}

static VALUE
vm_invoke_builtin(rb_execution_context_t *ec, rb_control_frame_t *cfp, const struct rb_builtin_function* bf, const VALUE *argv)
{
    return invoke_bf(ec, cfp, bf, argv);
}

static VALUE
vm_invoke_builtin_delegate(rb_execution_context_t *ec, rb_control_frame_t *cfp, const struct rb_builtin_function *bf, unsigned int start_index)
{
    if (0) { // debug print
        fputs("vm_invoke_builtin_delegate: passing -> ", stderr);
        for (int i=0; i<bf->argc; i++) {
            ruby_debug_printf(":%s ", rb_id2name(ISEQ_BODY(cfp->iseq)->local_table[i+start_index]));
        }
        ruby_debug_printf("\n" "%s %s(%d):%p\n", RUBY_FUNCTION_NAME_STRING, bf->name, bf->argc, bf->func_ptr);
    }

    if (bf->argc == 0) {
        return invoke_bf(ec, cfp, bf, NULL);
    }
    else {
        const VALUE *argv = cfp->ep - ISEQ_BODY(cfp->iseq)->local_table_size - VM_ENV_DATA_SIZE + 1 + start_index;
        return invoke_bf(ec, cfp, bf, argv);
    }
}

// for __builtin_inline!()

VALUE
rb_vm_lvar_exposed(rb_execution_context_t *ec, int index)
{
    const rb_control_frame_t *cfp = ec->cfp;
    return cfp->ep[index];
}