ruby--ruby/insns.def

/* -*- C -*-
  insns.def - YARV instruction definitions

  $Author: $
  created at: 04/01/01 01:17:55 JST

  Copyright (C) 2004-2007 Koichi Sasada
  Massive rewrite by @shyouhei in 2017.
 */

/* Some comments about this file's contents:

   - The new format aims to be editable by C editor of your choice;
     your mileage might vary of course.

   - Each instructions are in following format:

     DEFINE_INSN
     instruction_name
     (type operand, type operand, ..)
     (pop_values, ..)
     (return values ..)
     // attr type name contents..
     {
       .. // insn body
     }

   - Unlike the old format which was line-oriented, you can now place
     newlines and comments at liberal positions.

   - `DEFINE_INSN` is a keyword.

   - An instruction name must be a valid C identifier.

   - Operands, pop values, return values are series of either variable
     declarations, keyword `void`, or keyword `...`.  They are much
     like C function declarations.

   - Attribute pragmas are optional, and can include arbitrary C
     expressions.  You can write anything there but as of writing,
     supported attributes are:

       * sp_inc: Used to dynamically calculate sp increase in
         `insn_stack_increase`.

       * handles_sp: If it is true, VM deals with sp in the insn.
         Default is if the instruction takes ISEQ operand or not.

       * leaf: indicates that the instruction is "leaf" i.e. it does
         not introduce new stack frame on top of it.
         If an instruction handles sp, that can never be a leaf.

   - Attributes can access operands, but not stack (push/pop) variables.

   - An instruction's body is a pure C block, copied verbatimly into
     the generated C source code.
 */

/* nop */
DEFINE_INSN
nop
()
()
()
{
    /* none */
}

/**********************************************************/
/* deal with variables                                    */
/**********************************************************/

/* Get local variable (pointed by `idx' and `level').
     'level' indicates the nesting depth from the current block.
 */
DEFINE_INSN
getlocal
(lindex_t idx, rb_num_t level)
()
(VALUE val)
{
    val = *(vm_get_ep(GET_EP(), level) - idx);
    RB_DEBUG_COUNTER_INC(lvar_get);
    (void)RB_DEBUG_COUNTER_INC_IF(lvar_get_dynamic, level > 0);
}

/* Set a local variable (pointed to by 'idx') as val.
     'level' indicates the nesting depth from the current block.
 */
DEFINE_INSN
setlocal
(lindex_t idx, rb_num_t level)
(VALUE val)
()
{
    vm_env_write(vm_get_ep(GET_EP(), level), -(int)idx, val);
    RB_DEBUG_COUNTER_INC(lvar_set);
    (void)RB_DEBUG_COUNTER_INC_IF(lvar_set_dynamic, level > 0);
}

/* Get a block parameter. */
DEFINE_INSN
getblockparam
(lindex_t idx, rb_num_t level)
()
(VALUE val)
{
    const VALUE *ep = vm_get_ep(GET_EP(), level);
    VM_ASSERT(VM_ENV_LOCAL_P(ep));

    if (!VM_ENV_FLAGS(ep, VM_FRAME_FLAG_MODIFIED_BLOCK_PARAM)) {
	val = rb_vm_bh_to_procval(ec, VM_ENV_BLOCK_HANDLER(ep));
	vm_env_write(ep, -(int)idx, val);
	VM_ENV_FLAGS_SET(ep, VM_FRAME_FLAG_MODIFIED_BLOCK_PARAM);
    }
    else {
	val = *(ep - idx);
	RB_DEBUG_COUNTER_INC(lvar_get);
	(void)RB_DEBUG_COUNTER_INC_IF(lvar_get_dynamic, level > 0);
    }
}

/* Set block parameter. */
DEFINE_INSN
setblockparam
(lindex_t idx, rb_num_t level)
(VALUE val)
()
{
    const VALUE *ep = vm_get_ep(GET_EP(), level);
    VM_ASSERT(VM_ENV_LOCAL_P(ep));

    vm_env_write(ep, -(int)idx, val);
    RB_DEBUG_COUNTER_INC(lvar_set);
    (void)RB_DEBUG_COUNTER_INC_IF(lvar_set_dynamic, level > 0);

    VM_ENV_FLAGS_SET(ep, VM_FRAME_FLAG_MODIFIED_BLOCK_PARAM);
}

/* Get special proxy object which only responds to `call` method if the block parameter
     represents a iseq/ifunc block. Otherwise, same as `getblockparam`.
 */
DEFINE_INSN
getblockparamproxy
(lindex_t idx, rb_num_t level)
()
(VALUE val)
{
    const VALUE *ep = vm_get_ep(GET_EP(), level);
    VM_ASSERT(VM_ENV_LOCAL_P(ep));

    if (!VM_ENV_FLAGS(ep, VM_FRAME_FLAG_MODIFIED_BLOCK_PARAM)) {
	VALUE block_handler = VM_ENV_BLOCK_HANDLER(ep);

	if (block_handler) {
	    switch (vm_block_handler_type(block_handler)) {
	      case block_handler_type_iseq:
	      case block_handler_type_ifunc:
		val = rb_block_param_proxy;
		break;
	      case block_handler_type_symbol:
		val = rb_sym_to_proc(VM_BH_TO_SYMBOL(block_handler));
		goto INSN_LABEL(set);
	      case block_handler_type_proc:
		val = VM_BH_TO_PROC(block_handler);
		goto INSN_LABEL(set);
	      default:
		VM_UNREACHABLE(getblockparamproxy);
	    }
	}
	else {
	    val = Qnil;
	  INSN_LABEL(set):
	    vm_env_write(ep, -(int)idx, val);
	    VM_ENV_FLAGS_SET(ep, VM_FRAME_FLAG_MODIFIED_BLOCK_PARAM);
	}
    }
    else {
	val = *(ep - idx);
	RB_DEBUG_COUNTER_INC(lvar_get);
	(void)RB_DEBUG_COUNTER_INC_IF(lvar_get_dynamic, level > 0);
    }
}

/* Get value of special local variable ($~, $_, ..). */
DEFINE_INSN
getspecial
(rb_num_t key, rb_num_t type)
()
(VALUE val)
/* `$~ = MatchData.allocate; $&` can raise. */
// attr bool leaf = (type == 0) ? true : false;
{
    val = vm_getspecial(ec, GET_LEP(), key, type);
}

/* Set value of special local variable ($~, $_, ...) to obj. */
DEFINE_INSN
setspecial
(rb_num_t key)
(VALUE obj)
()
{
    lep_svar_set(ec, GET_LEP(), key, obj);
}

/* Get value of instance variable id of self. */
DEFINE_INSN
getinstancevariable
(ID id, IVC ic)
()
(VALUE val)
/* Ractor crashes when it accesses class/module-level instances variables. */
// attr bool leaf = false; /* has IVAR_ACCESSOR_SHOULD_BE_MAIN_RACTOR() */
{
    val = vm_getinstancevariable(GET_ISEQ(), GET_SELF(), id, ic);
}

/* Set value of instance variable id of self to val. */
DEFINE_INSN
setinstancevariable
(ID id, IVC ic)
(VALUE val)
()
// attr bool leaf = false; /* has rb_check_frozen_internal() */
{
    vm_setinstancevariable(GET_ISEQ(), GET_SELF(), id, val, ic);
}

/* Get value of class variable id of klass as val. */
DEFINE_INSN
getclassvariable
(ID id)
()
(VALUE val)
/* "class variable access from toplevel" warning can be hooked. */
// attr bool leaf = false; /* has rb_warning() */
{
    val = rb_cvar_get(vm_get_cvar_base(vm_get_cref(GET_EP()), GET_CFP(), 1), id);
}

/* Set value of class variable id of klass as val. */
DEFINE_INSN
setclassvariable
(ID id)
(VALUE val)
()
/* "class variable access from toplevel" warning can be hooked. */
// attr bool leaf = false; /* has rb_warning() */
{
    vm_ensure_not_refinement_module(GET_SELF());
    rb_cvar_set(vm_get_cvar_base(vm_get_cref(GET_EP()), GET_CFP(), 1), id, val);
}

/* Get constant variable id. If klass is Qnil and allow_nil is Qtrue, constants
   are searched in the current scope. Otherwise, get constant under klass
   class or module.
 */
DEFINE_INSN
getconstant
(ID id)
(VALUE klass, VALUE allow_nil)
(VALUE val)
/* getconstant can kick autoload */
// attr bool leaf = false; /* has rb_autoload_load() */
{
    val = vm_get_ev_const(ec, klass, id, allow_nil == Qtrue, 0);
}

/* Set constant variable id under cbase class or module.
 */
DEFINE_INSN
setconstant
(ID id)
(VALUE val, VALUE cbase)
()
/* Assigning an object to a constant is basically a leaf operation.
 * The problem is, assigning a Module instance to a constant _names_
 * that module.  Naming involves string manipulations, which are
 * method calls. */
// attr bool leaf = false; /* has StringValue() */
{
    vm_check_if_namespace(cbase);
    vm_ensure_not_refinement_module(GET_SELF());
    rb_const_set(cbase, id, val);
}

/* get global variable id. */
DEFINE_INSN
getglobal
(ID gid)
()
(VALUE val)
// attr bool leaf = false;
{
    val = rb_gvar_get(gid);
}

/* set global variable id as val. */
DEFINE_INSN
setglobal
(ID gid)
(VALUE val)
()
// attr bool leaf = false;
{
    rb_gvar_set(gid, val);
}

/**********************************************************/
/* deal with values                                       */
/**********************************************************/

/* put nil to stack. */
DEFINE_INSN
putnil
()
()
(VALUE val)
{
    val = Qnil;
}

/* put self. */
DEFINE_INSN
putself
()
()
(VALUE val)
{
    val = GET_SELF();
}

/* put some object.
     i.e. Fixnum, true, false, nil, and so on.
 */
DEFINE_INSN
putobject
(VALUE val)
()
(VALUE val)
{
    /* */
}

/* put special object.  "value_type" is for expansion. */
DEFINE_INSN
putspecialobject
(rb_num_t value_type)
()
(VALUE val)
{
    enum vm_special_object_type type;

    type = (enum vm_special_object_type)value_type;
    val = vm_get_special_object(GET_EP(), type);
}

/* put string val. string will be copied. */
DEFINE_INSN
putstring
(VALUE str)
()
(VALUE val)
{
    val = rb_ec_str_resurrect(ec, str);
}

/* put concatenate strings */
DEFINE_INSN
concatstrings
(rb_num_t num)
(...)
(VALUE val)
/* This instruction can concat UTF-8 and binary strings, resulting in
 * Encoding::CompatibilityError. */
// attr bool leaf = false; /* has rb_enc_cr_str_buf_cat() */
// attr rb_snum_t sp_inc = 1 - (rb_snum_t)num;
{
    val = rb_str_concat_literals(num, STACK_ADDR_FROM_TOP(num));
}

/* push the result of to_s. */
DEFINE_INSN
tostring
()
(VALUE val, VALUE str)
(VALUE val)
{
    val = rb_obj_as_string_result(str, val);
}

/* compile str to Regexp and push it.
     opt is the option for the Regexp.
 */
DEFINE_INSN
toregexp
(rb_num_t opt, rb_num_t cnt)
(...)
(VALUE val)
/* This instruction can raise RegexpError, thus can call
 * RegexpError#initialize */
// attr bool leaf = false;
// attr rb_snum_t sp_inc = 1 - (rb_snum_t)cnt;
{
    const VALUE ary = rb_ary_tmp_new_from_values(0, cnt, STACK_ADDR_FROM_TOP(cnt));
    val = rb_reg_new_ary(ary, (int)opt);
    rb_ary_clear(ary);
}

/* intern str to Symbol and push it. */
DEFINE_INSN
intern
()
(VALUE str)
(VALUE sym)
{
    sym = rb_str_intern(str);
}

/* put new array initialized with num values on the stack. */
DEFINE_INSN
newarray
(rb_num_t num)
(...)
(VALUE val)
// attr rb_snum_t sp_inc = 1 - (rb_snum_t)num;
{
    val = rb_ec_ary_new_from_values(ec, num, STACK_ADDR_FROM_TOP(num));
}

/* put new array initialized with num values on the stack. There
   should be at least one element on the stack, and the top element
   should be a hash.  If the top element is empty, it is not
   included in the array.
 */
DEFINE_INSN
newarraykwsplat
(rb_num_t num)
(...)
(VALUE val)
// attr rb_snum_t sp_inc = 1 - (rb_snum_t)num;
{
    if (RHASH_EMPTY_P(*STACK_ADDR_FROM_TOP(1))) {
        val = rb_ary_new4(num-1, STACK_ADDR_FROM_TOP(num));
    }
    else {
        val = rb_ary_new4(num, STACK_ADDR_FROM_TOP(num));
    }
}

/* dup array */
DEFINE_INSN
duparray
(VALUE ary)
()
(VALUE val)
{
    RUBY_DTRACE_CREATE_HOOK(ARRAY, RARRAY_LEN(ary));
    val = rb_ary_resurrect(ary);
}

/* dup hash */
DEFINE_INSN
duphash
(VALUE hash)
()
(VALUE val)
{
    RUBY_DTRACE_CREATE_HOOK(HASH, RHASH_SIZE(hash) << 1);
    val = rb_hash_resurrect(hash);
}

/* if TOS is an array expand, expand it to num objects.
     if the number of the array is less than num, push nils to fill.
     if it is greater than num, exceeding elements are dropped.
     unless TOS is an array, push num - 1 nils.
     if flags is non-zero, push the array of the rest elements.
     flag: 0x01 - rest args array
     flag: 0x02 - for postarg
     flag: 0x04 - reverse?
 */
DEFINE_INSN
expandarray
(rb_num_t num, rb_num_t flag)
(..., VALUE ary)
(...)
// attr bool leaf = false; /* has rb_check_array_type() */
// attr rb_snum_t sp_inc = (rb_snum_t)num - 1 + (flag & 1 ? 1 : 0);
{
    vm_expandarray(GET_SP(), ary, num, (int)flag);
}

/* concat two arrays */
DEFINE_INSN
concatarray
()
(VALUE ary1, VALUE ary2)
(VALUE ary)
// attr bool leaf = false; /* has rb_check_array_type() */
{
    ary = vm_concat_array(ary1, ary2);
}

/* call to_a on array ary to splat */
DEFINE_INSN
splatarray
(VALUE flag)
(VALUE ary)
(VALUE obj)
// attr bool leaf = false; /* has rb_check_array_type() */
{
    obj = vm_splat_array(flag, ary);
}

/* put new Hash from n elements. n must be an even number. */
DEFINE_INSN
newhash
(rb_num_t num)
(...)
(VALUE val)
// attr bool leaf = false; /* has rb_hash_key_str() */
// attr rb_snum_t sp_inc = 1 - (rb_snum_t)num;
{
    RUBY_DTRACE_CREATE_HOOK(HASH, num);

    val = rb_hash_new_with_size(num / 2);

    if (num) {
        rb_hash_bulk_insert(num, STACK_ADDR_FROM_TOP(num), val);
    }
}

/* put new Range object.(Range.new(low, high, flag)) */
DEFINE_INSN
newrange
(rb_num_t flag)
(VALUE low, VALUE high)
(VALUE val)
/* rb_range_new() exercises "bad value for range" check. */
// attr bool leaf = false; /* see also: range.c:range_init() */
{
    val = rb_range_new(low, high, (int)flag);
}

/**********************************************************/
/* deal with stack operation                              */
/**********************************************************/

/* pop from stack. */
DEFINE_INSN
pop
()
(VALUE val)
()
{
    (void)val;
    /* none */
}

/* duplicate stack top. */
DEFINE_INSN
dup
()
(VALUE val)
(VALUE val1, VALUE val2)
{
    val1 = val2 = val;
}

/* duplicate stack top n elements */
DEFINE_INSN
dupn
(rb_num_t n)
(...)
(...)
// attr rb_snum_t sp_inc = n;
{
    void *dst = GET_SP();
    void *src = STACK_ADDR_FROM_TOP(n);

    MEMCPY(dst, src, VALUE, n);
}

/* swap top 2 vals */
DEFINE_INSN
swap
()
(VALUE val, VALUE obj)
(VALUE obj, VALUE val)
{
    /* none */
}

/* for stack caching. */
DEFINE_INSN_IF(STACK_CACHING)
reput
()
(..., VALUE val)
(VALUE val)
// attr rb_snum_t sp_inc = 0;
{
    /* none */
}

/* get nth stack value from stack top */
DEFINE_INSN
topn
(rb_num_t n)
(...)
(VALUE val)
// attr rb_snum_t sp_inc = 1;
{
    val = TOPN(n);
}

/* set Nth stack entry to stack top */
DEFINE_INSN
setn
(rb_num_t n)
(..., VALUE val)
(VALUE val)
// attr rb_snum_t sp_inc = 0;
{
    TOPN(n) = val;
}

/* empty current stack */
DEFINE_INSN
adjuststack
(rb_num_t n)
(...)
(...)
// attr rb_snum_t sp_inc = -(rb_snum_t)n;
{
    /* none */
}

/**********************************************************/
/* deal with setting                                      */
/**********************************************************/

/* defined? */
DEFINE_INSN
defined
(rb_num_t op_type, VALUE obj, VALUE pushval)
(VALUE v)
(VALUE val)
// attr bool leaf = leafness_of_defined(op_type);
{
    val = Qnil;
    if (vm_defined(ec, GET_CFP(), op_type, obj, v)) {
      val = pushval;
    }
}

/* check `target' matches `pattern'.
     `flag & VM_CHECKMATCH_TYPE_MASK' describe how to check pattern.
      VM_CHECKMATCH_TYPE_WHEN: ignore target and check pattern is truthy.
      VM_CHECKMATCH_TYPE_CASE: check `patten === target'.
      VM_CHECKMATCH_TYPE_RESCUE: check `pattern.kind_op?(Module) && pattern === target'.
     if `flag & VM_CHECKMATCH_ARRAY' is not 0, then `patten' is array of patterns.
 */
DEFINE_INSN
checkmatch
(rb_num_t flag)
(VALUE target, VALUE pattern)
(VALUE result)
// attr bool leaf = leafness_of_checkmatch(flag);
{
    result = vm_check_match(ec, target, pattern, flag);
}

/* check keywords are specified or not. */
DEFINE_INSN
checkkeyword
(lindex_t kw_bits_index, lindex_t keyword_index)
()
(VALUE ret)
{
    ret = vm_check_keyword(kw_bits_index, keyword_index, GET_EP());
}

/* check if val is type. */
DEFINE_INSN
checktype
(rb_num_t type)
(VALUE val)
(VALUE ret)
{
    ret = (TYPE(val) == (int)type) ? Qtrue : Qfalse;
}

/**********************************************************/
/* deal with control flow 1: class/module                 */
/**********************************************************/

/* enter class definition scope. if super is Qfalse, and class
   "klass" is defined, it's redefined. Otherwise, define "klass" class.
 */
DEFINE_INSN
defineclass
(ID id, ISEQ class_iseq, rb_num_t flags)
(VALUE cbase, VALUE super)
(VALUE val)
{
    VALUE klass = vm_find_or_create_class_by_id(id, flags, cbase, super);

    rb_iseq_check(class_iseq);

    /* enter scope */
    vm_push_frame(ec, class_iseq, VM_FRAME_MAGIC_CLASS | VM_ENV_FLAG_LOCAL, klass,
		  GET_BLOCK_HANDLER(),
		  (VALUE)vm_cref_push(ec, klass, NULL, FALSE),
		  class_iseq->body->iseq_encoded, GET_SP(),
		  class_iseq->body->local_table_size,
		  class_iseq->body->stack_max);
    RESTORE_REGS();
    NEXT_INSN();
}

DEFINE_INSN
definemethod
(ID id, ISEQ iseq)
()
()
{
    vm_define_method(ec, Qnil, id, (VALUE)iseq, FALSE);
}

DEFINE_INSN
definesmethod
(ID id, ISEQ iseq)
(VALUE obj)
()
{
    vm_define_method(ec, obj, id, (VALUE)iseq, TRUE);
}

/**********************************************************/
/* deal with control flow 2: method/iterator              */
/**********************************************************/

/* invoke method. */
DEFINE_INSN
send
(CALL_DATA cd, ISEQ blockiseq)
(...)
(VALUE val)
// attr rb_snum_t sp_inc = sp_inc_of_sendish(cd->ci);
// attr rb_snum_t comptime_sp_inc = sp_inc_of_sendish(ci);
{
    VALUE bh = vm_caller_setup_arg_block(ec, GET_CFP(), cd->ci, blockiseq, false);
    val = vm_sendish(ec, GET_CFP(), cd, bh, mexp_search_method);

    if (val == Qundef) {
        RESTORE_REGS();
        NEXT_INSN();
    }
}

/* Invoke method without block */
DEFINE_INSN
opt_send_without_block
(CALL_DATA cd)
(...)
(VALUE val)
// attr bool handles_sp = true;
// attr rb_snum_t sp_inc = sp_inc_of_sendish(cd->ci);
// attr rb_snum_t comptime_sp_inc = sp_inc_of_sendish(ci);
{
    VALUE bh = VM_BLOCK_HANDLER_NONE;
    val = vm_sendish(ec, GET_CFP(), cd, bh, mexp_search_method);

    if (val == Qundef) {
        RESTORE_REGS();
        NEXT_INSN();
    }
}

DEFINE_INSN
opt_str_freeze
(VALUE str, CALL_DATA cd)
()
(VALUE val)
{
    val = vm_opt_str_freeze(str, BOP_FREEZE, idFreeze);

    if (val == Qundef) {
        PUSH(rb_str_resurrect(str));
        CALL_SIMPLE_METHOD();
    }
}

/* optimized nil? */
DEFINE_INSN
opt_nil_p
(CALL_DATA cd)
(VALUE recv)
(VALUE val)
{
    val = vm_opt_nil_p(GET_ISEQ(), cd, recv);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

DEFINE_INSN
opt_str_uminus
(VALUE str, CALL_DATA cd)
()
(VALUE val)
{
    val = vm_opt_str_freeze(str, BOP_UMINUS, idUMinus);

    if (val == Qundef) {
        PUSH(rb_str_resurrect(str));
        CALL_SIMPLE_METHOD();
    }
}

DEFINE_INSN
opt_newarray_max
(rb_num_t num)
(...)
(VALUE val)
/* This instruction typically has no funcalls.  But it compares array
 * contents each other by nature.  That part could call methods when
 * necessary.  No way to detect such method calls beforehand.  We
 * cannot but mark it being not leaf. */
// attr bool leaf = false; /* has rb_funcall() */
// attr rb_snum_t sp_inc = 1 - (rb_snum_t)num;
{
    val = vm_opt_newarray_max(num, STACK_ADDR_FROM_TOP(num));
}

DEFINE_INSN
opt_newarray_min
(rb_num_t num)
(...)
(VALUE val)
/* Same discussion as opt_newarray_max. */
// attr bool leaf = false; /* has rb_funcall() */
// attr rb_snum_t sp_inc = 1 - (rb_snum_t)num;
{
    val = vm_opt_newarray_min(num, STACK_ADDR_FROM_TOP(num));
}

/* super(args) # args.size => num */
DEFINE_INSN
invokesuper
(CALL_DATA cd, ISEQ blockiseq)
(...)
(VALUE val)
// attr rb_snum_t sp_inc = sp_inc_of_sendish(cd->ci);
// attr rb_snum_t comptime_sp_inc = sp_inc_of_sendish(ci);
{
    VALUE bh = vm_caller_setup_arg_block(ec, GET_CFP(), cd->ci, blockiseq, true);
    val = vm_sendish(ec, GET_CFP(), cd, bh, mexp_search_super);

    if (val == Qundef) {
        RESTORE_REGS();
        NEXT_INSN();
    }
}

/* yield(args) */
DEFINE_INSN
invokeblock
(CALL_DATA cd)
(...)
(VALUE val)
// attr bool handles_sp = true;
// attr rb_snum_t sp_inc = sp_inc_of_invokeblock(cd->ci);
// attr rb_snum_t comptime_sp_inc = sp_inc_of_invokeblock(ci);
{
    VALUE bh = VM_BLOCK_HANDLER_NONE;
    val = vm_sendish(ec, GET_CFP(), cd, bh, mexp_search_invokeblock);

    if (val == Qundef) {
        RESTORE_REGS();
        NEXT_INSN();
    }
}

/* return from this scope. */
DEFINE_INSN
leave
()
(VALUE val)
(VALUE val)
/* This is super surprising but when leaving from a frame, we check
 * for interrupts.  If any, that should be executed on top of the
 * current execution context.  This is a method call. */
// attr bool leaf = false; /* has rb_threadptr_execute_interrupts() */
// attr bool handles_sp = true;
{
    if (OPT_CHECKED_RUN) {
        const VALUE *const bp = vm_base_ptr(GET_CFP());
        if (GET_SP() != bp) {
            vm_stack_consistency_error(ec, GET_CFP(), bp);
	}
    }

    if (vm_pop_frame(ec, GET_CFP(), GET_EP())) {
#if OPT_CALL_THREADED_CODE
	rb_ec_thread_ptr(ec)->retval = val;
	return 0;
#else
	return val;
#endif
    }
    else {
	RESTORE_REGS();
    }
}

/**********************************************************/
/* deal with control flow 3: exception                    */
/**********************************************************/

/* longjump */
DEFINE_INSN
throw
(rb_num_t throw_state)
(VALUE throwobj)
(VALUE val)
/* Same discussion as leave. */
// attr bool leaf = false; /* has rb_threadptr_execute_interrupts() */
{
    val = vm_throw(ec, GET_CFP(), throw_state, throwobj);
    THROW_EXCEPTION(val);
    /* unreachable */
}

/**********************************************************/
/* deal with control flow 4: local jump                   */
/**********************************************************/

/* set PC to (PC + dst). */
DEFINE_INSN
jump
(OFFSET dst)
()
()
/* Same discussion as leave. */
// attr bool leaf = leafness_of_check_ints; /* has rb_threadptr_execute_interrupts() */
{
    RUBY_VM_CHECK_INTS(ec);
    JUMP(dst);
}

/* if val is not false or nil, set PC to (PC + dst). */
DEFINE_INSN
branchif
(OFFSET dst)
(VALUE val)
()
/* Same discussion as jump. */
// attr bool leaf = leafness_of_check_ints; /* has rb_threadptr_execute_interrupts() */
{
    if (RTEST(val)) {
	RUBY_VM_CHECK_INTS(ec);
	JUMP(dst);
    }
}

/* if val is false or nil, set PC to (PC + dst). */
DEFINE_INSN
branchunless
(OFFSET dst)
(VALUE val)
()
/* Same discussion as jump. */
// attr bool leaf = leafness_of_check_ints; /* has rb_threadptr_execute_interrupts() */
{
    if (!RTEST(val)) {
	RUBY_VM_CHECK_INTS(ec);
	JUMP(dst);
    }
}

/* if val is nil, set PC to (PC + dst). */
DEFINE_INSN
branchnil
(OFFSET dst)
(VALUE val)
()
/* Same discussion as jump. */
// attr bool leaf = leafness_of_check_ints; /* has rb_threadptr_execute_interrupts() */
{
    if (NIL_P(val)) {
	RUBY_VM_CHECK_INTS(ec);
	JUMP(dst);
    }
}

/**********************************************************/
/* for optimize                                           */
/**********************************************************/

/* push inline-cached value and go to dst if it is valid */
DEFINE_INSN
opt_getinlinecache
(OFFSET dst, IC ic)
()
(VALUE val)
{
    struct iseq_inline_constant_cache_entry *ice = ic->entry;
    if (ice && vm_ic_hit_p(ice, GET_EP())) {
        val = ice->value;
        JUMP(dst);
    }
    else {
	val = Qnil;
    }
}

/* set inline cache */
DEFINE_INSN
opt_setinlinecache
(IC ic)
(VALUE val)
(VALUE val)
{
    vm_ic_update(GET_ISEQ(), ic, val, GET_EP());
}

/* run iseq only once */
DEFINE_INSN
once
(ISEQ iseq, ISE ise)
()
(VALUE val)
{
    val = vm_once_dispatch(ec, iseq, ise);
}

/* case dispatcher, jump by table if possible */
DEFINE_INSN
opt_case_dispatch
(CDHASH hash, OFFSET else_offset)
(..., VALUE key)
()
// attr rb_snum_t sp_inc = -1;
{
    OFFSET dst = vm_case_dispatch(hash, else_offset, key);

    if (dst) {
	JUMP(dst);
    }
}

/** simple functions */

/* optimized X+Y. */
DEFINE_INSN
opt_plus
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = vm_opt_plus(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X-Y. */
DEFINE_INSN
opt_minus
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = vm_opt_minus(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X*Y. */
DEFINE_INSN
opt_mult
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = vm_opt_mult(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X/Y. */
DEFINE_INSN
opt_div
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
/* In case of division by zero, it raises. Thus
 * ZeroDivisionError#initialize is called.  */
// attr bool leaf = false;
{
    val = vm_opt_div(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X%Y. */
DEFINE_INSN
opt_mod
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
/* Same discussion as opt_div. */
// attr bool leaf = false;
{
    val = vm_opt_mod(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X==Y. */
DEFINE_INSN
opt_eq
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = opt_equality(GET_ISEQ(), recv, obj, cd);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X!=Y. */
DEFINE_INSN
opt_neq
(CALL_DATA cd_eq, CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = vm_opt_neq(GET_ISEQ(), cd, cd_eq, recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X<Y. */
DEFINE_INSN
opt_lt
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = vm_opt_lt(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X<=Y. */
DEFINE_INSN
opt_le
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = vm_opt_le(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X>Y. */
DEFINE_INSN
opt_gt
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = vm_opt_gt(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X>=Y. */
DEFINE_INSN
opt_ge
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = vm_opt_ge(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* << */
DEFINE_INSN
opt_ltlt
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
/* This instruction can append an integer, as a codepoint, into a
 * string.  Then what happens if that codepoint does not exist in the
 * string's encoding?  Of course an exception.  That's not a leaf. */
// attr bool leaf = false; /* has "invalid codepoint" exception */
{
    val = vm_opt_ltlt(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X&Y. */
DEFINE_INSN
opt_and
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = vm_opt_and(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized X|Y. */
DEFINE_INSN
opt_or
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
{
    val = vm_opt_or(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* [] */
DEFINE_INSN
opt_aref
(CALL_DATA cd)
(VALUE recv, VALUE obj)
(VALUE val)
/* This is complicated.  In case of hash, vm_opt_aref() resorts to
 * rb_hash_aref().  If `recv` has no `obj`, this function then yields
 * default_proc.  This is a method call.  So opt_aref is
 * (surprisingly) not leaf. */
// attr bool leaf = false; /* has rb_funcall() */ /* calls #yield */
{
    val = vm_opt_aref(recv, obj);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* recv[obj] = set */
DEFINE_INSN
opt_aset
(CALL_DATA cd)
(VALUE recv, VALUE obj, VALUE set)
(VALUE val)
/* This is another story than opt_aref.  When vm_opt_aset() resorts
 * to rb_hash_aset(), which should call #hash for `obj`. */
// attr bool leaf = false; /* has rb_funcall() */ /* calls #hash */
{
    val = vm_opt_aset(recv, obj, set);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* recv[str] = set */
DEFINE_INSN
opt_aset_with
(VALUE key, CALL_DATA cd)
(VALUE recv, VALUE val)
(VALUE val)
/* Same discussion as opt_aset. */
// attr bool leaf = false; /* has rb_funcall() */ /* calls #hash */
{
    VALUE tmp = vm_opt_aset_with(recv, key, val);

    if (tmp != Qundef) {
	val = tmp;
    }
    else {
#ifndef MJIT_HEADER
	TOPN(0) = rb_str_resurrect(key);
	PUSH(val);
#endif
        CALL_SIMPLE_METHOD();
    }
}

/* recv[str] */
DEFINE_INSN
opt_aref_with
(VALUE key, CALL_DATA cd)
(VALUE recv)
(VALUE val)
/* Same discussion as opt_aref. */
// attr bool leaf = false; /* has rb_funcall() */ /* calls #yield */
{
    val = vm_opt_aref_with(recv, key);

    if (val == Qundef) {
#ifndef MJIT_HEADER
	PUSH(rb_str_resurrect(key));
#endif
        CALL_SIMPLE_METHOD();
    }
}

/* optimized length */
DEFINE_INSN
opt_length
(CALL_DATA cd)
(VALUE recv)
(VALUE val)
{
    val = vm_opt_length(recv, BOP_LENGTH);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized size */
DEFINE_INSN
opt_size
(CALL_DATA cd)
(VALUE recv)
(VALUE val)
{
    val = vm_opt_length(recv, BOP_SIZE);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized empty? */
DEFINE_INSN
opt_empty_p
(CALL_DATA cd)
(VALUE recv)
(VALUE val)
{
    val = vm_opt_empty_p(recv);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized succ */
DEFINE_INSN
opt_succ
(CALL_DATA cd)
(VALUE recv)
(VALUE val)
{
    val = vm_opt_succ(recv);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized not */
DEFINE_INSN
opt_not
(CALL_DATA cd)
(VALUE recv)
(VALUE val)
{
    val = vm_opt_not(GET_ISEQ(), cd, recv);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* optimized regexp match 2 */
DEFINE_INSN
opt_regexpmatch2
(CALL_DATA cd)
(VALUE obj2, VALUE obj1)
(VALUE val)
// attr bool leaf = false; /* match_at() has rb_thread_check_ints() */
{
    val = vm_opt_regexpmatch2(obj2, obj1);

    if (val == Qundef) {
        CALL_SIMPLE_METHOD();
    }
}

/* call native compiled method */
DEFINE_INSN_IF(SUPPORT_CALL_C_FUNCTION)
opt_call_c_function
(rb_insn_func_t funcptr)
()
()
// attr bool leaf = false; /* anything can happen inside */
// attr bool handles_sp = true;
{
    reg_cfp = (funcptr)(ec, reg_cfp);

    if (reg_cfp == 0) {
	VALUE err = ec->errinfo;
	ec->errinfo = Qnil;
	THROW_EXCEPTION(err);
    }

    RESTORE_REGS();
    NEXT_INSN();
}

/* call specific function with args */
DEFINE_INSN
invokebuiltin
(RB_BUILTIN bf)
(...)
(VALUE val)
// attr bool leaf = false; /* anything can happen inside */
// attr rb_snum_t sp_inc = 1 - bf->argc;
{
    val = vm_invoke_builtin(ec, reg_cfp, bf, STACK_ADDR_FROM_TOP(bf->argc));
}

/* call specific function with args (same parameters) */
DEFINE_INSN
opt_invokebuiltin_delegate
(RB_BUILTIN bf, rb_num_t index)
()
(VALUE val)
// attr bool leaf = false; /* anything can happen inside */
{
    val = vm_invoke_builtin_delegate(ec, reg_cfp, bf, (unsigned int)index);
}

/* call specific function with args (same parameters) and leave */
DEFINE_INSN
opt_invokebuiltin_delegate_leave
(RB_BUILTIN bf, rb_num_t index)
()
(VALUE val)
// attr bool leaf = false; /* anything can happen inside */
{
    val = vm_invoke_builtin_delegate(ec, reg_cfp, bf, (unsigned int)index);

    /* leave fastpath */
    /* TracePoint/return fallbacks this insn to opt_invokebuiltin_delegate */
    if (vm_pop_frame(ec, GET_CFP(), GET_EP())) {
#if OPT_CALL_THREADED_CODE
        rb_ec_thread_ptr(ec)->retval = val;
        return 0;
#else
        return val;
#endif
    }
    else {
        RESTORE_REGS();
    }
}

/* BLT */
DEFINE_INSN_IF(SUPPORT_JOKE)
bitblt
()
()
(VALUE ret)
{
    ret = rb_str_new2("a bit of bacon, lettuce and tomato");
}

/* The Answer to Life, the Universe, and Everything */
DEFINE_INSN_IF(SUPPORT_JOKE)
answer
()
()
(VALUE ret)
{
    ret = INT2FIX(42);
}