root/vm.c

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DEFINITIONS

This source file includes following definitions.
  1. VM_EP_LEP
  2. rb_vm_search_cf_from_ep
  3. rb_vm_ep_local_ep
  4. VM_CF_LEP
  5. VM_CF_PREV_EP
  6. VM_CF_BLOCK_PTR
  7. rb_vm_control_frame_block_ptr
  8. vm_cref_new0
  9. vm_cref_new
  10. vm_cref_new_use_prev
  11. vm_cref_dup
  12. vm_cref_new_toplevel
  13. rb_vm_cref_new_toplevel
  14. vm_cref_dump
  15. rb_next_class_serial
  16. rb_vm_inc_const_missing_count
  17. ruby_th_dtrace_setup
  18. vm_stat
  19. vm_set_top_stack
  20. vm_set_eval_stack
  21. vm_set_main_stack
  22. rb_vm_get_binding_creatable_next_cfp
  23. rb_vm_get_ruby_level_next_cfp
  24. vm_get_ruby_level_caller_cfp
  25. rb_vm_pop_cfunc_frame
  26. rb_vm_rewind_cfp
  27. rb_frame_pop
  28. ruby_vm_at_exit
  29. ruby_vm_run_at_exit_hooks
  30. env_mark
  31. env_memsize
  32. check_env
  33. check_env_value
  34. vm_make_proc_from_block
  35. vm_make_env_each
  36. vm_make_env_object
  37. rb_vm_stack_to_heap
  38. rb_vm_env_prev_envval
  39. collect_local_variables_in_iseq
  40. collect_local_variables_in_env
  41. vm_collect_local_variables_in_heap
  42. rb_vm_env_local_variables
  43. rb_iseq_local_variables
  44. rb_proc_create
  45. rb_vm_make_proc
  46. rb_vm_make_proc_lambda
  47. rb_vm_proc_envval
  48. rb_vm_make_binding
  49. rb_binding_add_dynavars
  50. invoke_block
  51. invoke_bmethod
  52. invoke_block_from_c_0
  53. invoke_block_from_c_splattable
  54. invoke_block_from_c_unsplattable
  55. check_block
  56. vm_yield_with_cref
  57. vm_yield
  58. vm_yield_with_block
  59. vm_invoke_proc
  60. vm_invoke_bmethod
  61. rb_vm_invoke_proc
  62. vm_normal_frame
  63. vm_cfp_svar_get
  64. vm_cfp_svar_set
  65. vm_svar_get
  66. vm_svar_set
  67. rb_backref_get
  68. rb_backref_set
  69. rb_lastline_get
  70. rb_lastline_set
  71. rb_sourcefilename
  72. rb_sourcefile
  73. rb_sourceline
  74. rb_source_location
  75. rb_source_loc
  76. rb_vm_cref
  77. rb_vm_cref_replace_with_duplicated_cref
  78. rb_vm_cref_in_context
  79. debug_cref
  80. rb_vm_cbase
  81. make_localjump_error
  82. rb_vm_localjump_error
  83. rb_vm_make_jump_tag_but_local_jump
  84. rb_vm_jump_tag_but_local_jump
  85. vm_iter_break
  86. rb_iter_break
  87. rb_iter_break_value
  88. vm_redefinition_check_flag
  89. rb_vm_check_redefinition_opt_method
  90. check_redefined_method
  91. rb_vm_check_redefinition_by_prepend
  92. add_opt_method
  93. vm_init_redefined_flag
  94. vm_frametype_name
  95. hook_before_rewind
  96. vm_exec
  97. rb_iseq_eval
  98. rb_iseq_eval_main
  99. rb_vm_control_frame_id_and_class
  100. rb_thread_method_id_and_class
  101. rb_frame_method_id_and_class
  102. rb_thread_current_status
  103. rb_vm_call_cfunc
  104. rb_vm_mark
  105. rb_vm_register_special_exception
  106. rb_vm_add_root_module
  107. free_loading_table_entry
  108. ruby_vm_destruct
  109. vm_memsize
  110. vm_default_params
  111. get_param
  112. check_machine_stack_size
  113. vm_default_params_setup
  114. vm_init2
  115. thread_recycle_stack
  116. rb_thread_recycle_stack_release
  117. rb_thread_mark
  118. thread_free
  119. thread_memsize
  120. rb_obj_is_thread
  121. thread_alloc
  122. th_init
  123. ruby_thread_init
  124. rb_thread_alloc
  125. vm_define_method
  126. m_core_define_method
  127. m_core_define_singleton_method
  128. m_core_set_method_alias
  129. m_core_set_variable_alias
  130. m_core_undef_method
  131. m_core_set_postexe
  132. core_hash_merge
  133. m_core_hash_from_ary
  134. core_hash_from_ary
  135. m_core_hash_merge_ary
  136. core_hash_merge_ary
  137. m_core_hash_merge_ptr
  138. kwmerge_i
  139. kwcheck_i
  140. m_core_hash_merge_kwd
  141. core_hash_merge_kwd
  142. sdr
  143. nsdr
  144. Init_VM
  145. rb_vm_set_progname
  146. Init_BareVM
  147. Init_vm_objects
  148. main_to_s
  149. rb_vm_top_self
  150. Init_top_self
  151. ruby_vm_verbose_ptr
  152. ruby_vm_debug_ptr
  153. rb_ruby_verbose_ptr
  154. rb_ruby_debug_ptr
  155. rb_vm_fstring_table
  156. vm_analysis_insn
  157. vm_analysis_operand
  158. vm_analysis_register
  159. usage_analysis_insn_stop
  160. usage_analysis_operand_stop
  161. usage_analysis_register_stop
  162. vm_collect_usage_insn
  163. vm_collect_usage_operand
  164. vm_collect_usage_register

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

  vm.c -

  $Author: akr $

  Copyright (C) 2004-2007 Koichi Sasada

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

#ifndef VM_CHECK_MODE
#define VM_CHECK_MODE 0
#endif

#include "internal.h"
#include "ruby/vm.h"
#include "ruby/st.h"

#include "gc.h"
#include "vm_core.h"
#include "iseq.h"
#include "eval_intern.h"
#include "probes.h"
#include "probes_helper.h"

VALUE rb_str_concat_literals(size_t, const VALUE*);

PUREFUNC(static inline VALUE *VM_EP_LEP(VALUE *));
static inline VALUE *
VM_EP_LEP(VALUE *ep)
{
    while (!VM_EP_LEP_P(ep)) {
        ep = VM_EP_PREV_EP(ep);
    }
    return ep;
}

static inline rb_control_frame_t *
rb_vm_search_cf_from_ep(const rb_thread_t * const th, rb_control_frame_t *cfp, const VALUE * const ep)
{
    if (!ep) {
        return NULL;
    }
    else {
        const rb_control_frame_t * const eocfp = RUBY_VM_END_CONTROL_FRAME(th); /* end of control frame pointer */

        while (cfp < eocfp) {
            if (cfp->ep == ep) {
                return cfp;
            }
            cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
        }

        return NULL;
    }
}

VALUE *
rb_vm_ep_local_ep(VALUE *ep)
{
    return VM_EP_LEP(ep);
}

PUREFUNC(static inline VALUE *VM_CF_LEP(const rb_control_frame_t * const cfp));
static inline VALUE *
VM_CF_LEP(const rb_control_frame_t * const cfp)
{
    return VM_EP_LEP(cfp->ep);
}

static inline VALUE *
VM_CF_PREV_EP(const rb_control_frame_t * const cfp)
{
    return VM_EP_PREV_EP(cfp->ep);
}

PUREFUNC(static inline rb_block_t *VM_CF_BLOCK_PTR(const rb_control_frame_t * const cfp));
static inline rb_block_t *
VM_CF_BLOCK_PTR(const rb_control_frame_t * const cfp)
{
    VALUE *ep = VM_CF_LEP(cfp);
    return VM_EP_BLOCK_PTR(ep);
}

rb_block_t *
rb_vm_control_frame_block_ptr(const rb_control_frame_t *cfp)
{
    return VM_CF_BLOCK_PTR(cfp);
}

static rb_cref_t *
vm_cref_new0(VALUE klass, rb_method_visibility_t visi, int module_func, rb_cref_t *prev_cref, int pushed_by_eval, int use_prev_prev)
{
    VALUE refinements = Qnil;
    int omod_shared = FALSE;
    rb_cref_t *cref;

    /* scope */
    union {
        rb_scope_visibility_t visi;
        VALUE value;
    } scope_visi;

    scope_visi.visi.method_visi = visi;
    scope_visi.visi.module_func = module_func;

    /* refinements */
    if (prev_cref != NULL && prev_cref != (void *)1 /* TODO: why CREF_NEXT(cref) is 1? */) {
        refinements = CREF_REFINEMENTS(prev_cref);

        if (!NIL_P(refinements)) {
            omod_shared = TRUE;
            CREF_OMOD_SHARED_SET(prev_cref);
        }
    }

    cref = (rb_cref_t *)rb_imemo_new(imemo_cref, klass, (VALUE)(use_prev_prev ? CREF_NEXT(prev_cref) : prev_cref), scope_visi.value, refinements);

    if (pushed_by_eval) CREF_PUSHED_BY_EVAL_SET(cref);
    if (omod_shared) CREF_OMOD_SHARED_SET(cref);

    return cref;
}

static rb_cref_t *
vm_cref_new(VALUE klass, rb_method_visibility_t visi, int module_func, rb_cref_t *prev_cref, int pushed_by_eval)
{
    return vm_cref_new0(klass, visi, module_func, prev_cref, pushed_by_eval, FALSE);
}

static rb_cref_t *
vm_cref_new_use_prev(VALUE klass, rb_method_visibility_t visi, int module_func, rb_cref_t *prev_cref, int pushed_by_eval)
{
    return vm_cref_new0(klass, visi, module_func, prev_cref, pushed_by_eval, TRUE);
}

static rb_cref_t *
vm_cref_dup(const rb_cref_t *cref)
{
    VALUE klass = CREF_CLASS(cref);
    const rb_scope_visibility_t *visi = CREF_SCOPE_VISI(cref);
    rb_cref_t *next_cref = CREF_NEXT(cref), *new_cref;
    int pushed_by_eval = CREF_PUSHED_BY_EVAL(cref);

    new_cref = vm_cref_new(klass, visi->method_visi, visi->module_func, next_cref, pushed_by_eval);

    if (!NIL_P(CREF_REFINEMENTS(cref))) {
        CREF_REFINEMENTS_SET(new_cref, rb_hash_dup(CREF_REFINEMENTS(cref)));
        CREF_OMOD_SHARED_UNSET(new_cref);
    }

    return new_cref;
}

static rb_cref_t *
vm_cref_new_toplevel(rb_thread_t *th)
{
    rb_cref_t *cref = vm_cref_new(rb_cObject, METHOD_VISI_PRIVATE /* toplevel visibility is private */, FALSE, NULL, FALSE);

    if (th->top_wrapper) {
        cref = vm_cref_new(th->top_wrapper, METHOD_VISI_PRIVATE, FALSE, cref, FALSE);
    }

    return cref;
}

rb_cref_t *
rb_vm_cref_new_toplevel(void)
{
    return vm_cref_new_toplevel(GET_THREAD());
}

static void
vm_cref_dump(const char *mesg, const rb_cref_t *cref)
{
    fprintf(stderr, "vm_cref_dump: %s (%p)\n", mesg, cref);

    while (cref) {
        fprintf(stderr, "= cref| klass: %s\n", RSTRING_PTR(rb_class_path(CREF_CLASS(cref))));
        cref = CREF_NEXT(cref);
    }
}

#if VM_COLLECT_USAGE_DETAILS
static void vm_collect_usage_operand(int insn, int n, VALUE op);
static void vm_collect_usage_insn(int insn);
static void vm_collect_usage_register(int reg, int isset);
#endif

static VALUE vm_make_env_object(rb_thread_t *th, rb_control_frame_t *cfp);

static VALUE
vm_invoke_bmethod(rb_thread_t *th, rb_proc_t *proc, VALUE self,
                  int argc, const VALUE *argv, const rb_block_t *blockptr);
static VALUE
vm_invoke_proc(rb_thread_t *th, rb_proc_t *proc, VALUE self,
               int argc, const VALUE *argv, const rb_block_t *blockptr);

static rb_serial_t ruby_vm_global_method_state = 1;
static rb_serial_t ruby_vm_global_constant_state = 1;
static rb_serial_t ruby_vm_class_serial = 1;

#include "vm_insnhelper.h"
#include "vm_insnhelper.c"
#include "vm_exec.h"
#include "vm_exec.c"

#include "vm_method.c"
#include "vm_eval.c"

#define PROCDEBUG 0

rb_serial_t
rb_next_class_serial(void)
{
    return NEXT_CLASS_SERIAL();
}

VALUE rb_cRubyVM;
VALUE rb_cThread;
VALUE rb_cEnv;
VALUE rb_mRubyVMFrozenCore;

#define ruby_vm_redefined_flag GET_VM()->redefined_flag
VALUE ruby_vm_const_missing_count = 0;
rb_thread_t *ruby_current_thread = 0;
rb_vm_t *ruby_current_vm = 0;
rb_event_flag_t ruby_vm_event_flags;

static void thread_free(void *ptr);

void
rb_vm_inc_const_missing_count(void)
{
    ruby_vm_const_missing_count +=1;
}

VALUE rb_class_path_no_cache(VALUE _klass);

int
ruby_th_dtrace_setup(rb_thread_t *th, VALUE klass, ID id,
                     struct ruby_dtrace_method_hook_args *args)
{
    enum ruby_value_type type;
    if (!klass) {
        if (!th) th = GET_THREAD();
        if (!rb_thread_method_id_and_class(th, &id, &klass) || !klass)
            return FALSE;
    }
    if (RB_TYPE_P(klass, T_ICLASS)) {
        klass = RBASIC(klass)->klass;
    }
    else if (FL_TEST(klass, FL_SINGLETON)) {
        klass = rb_attr_get(klass, id__attached__);
        if (NIL_P(klass)) return FALSE;
    }
    type = BUILTIN_TYPE(klass);
    if (type == T_CLASS || type == T_ICLASS || type == T_MODULE) {
        VALUE name = rb_class_path_no_cache(klass);
        const char *classname, *filename;
        const char *methodname = rb_id2name(id);
        if (methodname && (filename = rb_source_loc(&args->line_no)) != 0) {
            if (NIL_P(name) || !(classname = StringValuePtr(name)))
                classname = "<unknown>";
            args->classname = classname;
            args->methodname = methodname;
            args->filename = filename;
            args->klass = klass;
            args->name = name;
            return TRUE;
        }
    }
    return FALSE;
}

/*
 *  call-seq:
 *    RubyVM.stat -> Hash
 *    RubyVM.stat(hsh) -> hsh
 *    RubyVM.stat(Symbol) -> Numeric
 *
 *  Returns a Hash containing implementation-dependent counters inside the VM.
 *
 *  This hash includes information about method/constant cache serials:
 *
 *    {
 *      :global_method_state=>251,
 *      :global_constant_state=>481,
 *      :class_serial=>9029
 *    }
 *
 *  The contents of the hash are implementation specific and may be changed in
 *  the future.
 *
 *  This method is only expected to work on C Ruby.
 */

static VALUE
vm_stat(int argc, VALUE *argv, VALUE self)
{
    static VALUE sym_global_method_state, sym_global_constant_state, sym_class_serial;
    VALUE arg = Qnil;
    VALUE hash = Qnil, key = Qnil;

    if (rb_scan_args(argc, argv, "01", &arg) == 1) {
        if (SYMBOL_P(arg))
            key = arg;
        else if (RB_TYPE_P(arg, T_HASH))
            hash = arg;
        else
            rb_raise(rb_eTypeError, "non-hash or symbol given");
    }
    else if (NIL_P(arg)) {
        hash = rb_hash_new();
    }

    if (sym_global_method_state == 0) {
#define S(s) sym_##s = ID2SYM(rb_intern_const(#s))
        S(global_method_state);
        S(global_constant_state);
        S(class_serial);
#undef S
    }

#define SET(name, attr) \
    if (key == sym_##name) \
        return SERIALT2NUM(attr); \
    else if (hash != Qnil) \
        rb_hash_aset(hash, sym_##name, SERIALT2NUM(attr));

    SET(global_method_state, ruby_vm_global_method_state);
    SET(global_constant_state, ruby_vm_global_constant_state);
    SET(class_serial, ruby_vm_class_serial);
#undef SET

    if (!NIL_P(key)) { /* matched key should return above */
        rb_raise(rb_eArgError, "unknown key: %"PRIsVALUE, rb_sym2str(key));
    }

    return hash;
}

/* control stack frame */

static void
vm_set_top_stack(rb_thread_t *th, const rb_iseq_t *iseq)
{
    if (iseq->body->type != ISEQ_TYPE_TOP) {
        rb_raise(rb_eTypeError, "Not a toplevel InstructionSequence");
    }

    /* for return */
    vm_push_frame(th, iseq, VM_FRAME_MAGIC_TOP | VM_FRAME_FLAG_FINISH, th->top_self,
                  VM_ENVVAL_BLOCK_PTR(0),
                  (VALUE)vm_cref_new_toplevel(th), /* cref or me */
                  iseq->body->iseq_encoded, th->cfp->sp, iseq->body->local_size, iseq->body->stack_max);
}

static void
vm_set_eval_stack(rb_thread_t * th, const rb_iseq_t *iseq, const rb_cref_t *cref, rb_block_t *base_block)
{
    vm_push_frame(th, iseq, VM_FRAME_MAGIC_EVAL | VM_FRAME_FLAG_FINISH,
                  base_block->self, VM_ENVVAL_PREV_EP_PTR(base_block->ep),
                  (VALUE)cref, /* cref or me */
                  iseq->body->iseq_encoded,
                  th->cfp->sp, iseq->body->local_size, iseq->body->stack_max);
}

static void
vm_set_main_stack(rb_thread_t *th, const rb_iseq_t *iseq)
{
    VALUE toplevel_binding = rb_const_get(rb_cObject, rb_intern("TOPLEVEL_BINDING"));
    rb_binding_t *bind;
    rb_env_t *env;

    GetBindingPtr(toplevel_binding, bind);
    GetEnvPtr(bind->env, env);

    vm_set_eval_stack(th, iseq, 0, &env->block);

    /* save binding */
    if (bind && iseq->body->local_size > 0) {
        bind->env = vm_make_env_object(th, th->cfp);
    }
}

rb_control_frame_t *
rb_vm_get_binding_creatable_next_cfp(const rb_thread_t *th, const rb_control_frame_t *cfp)
{
    while (!RUBY_VM_CONTROL_FRAME_STACK_OVERFLOW_P(th, cfp)) {
        if (cfp->iseq) {
            return (rb_control_frame_t *)cfp;
        }
        cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
    }
    return 0;
}

rb_control_frame_t *
rb_vm_get_ruby_level_next_cfp(const rb_thread_t *th, const rb_control_frame_t *cfp)
{
    while (!RUBY_VM_CONTROL_FRAME_STACK_OVERFLOW_P(th, cfp)) {
        if (RUBY_VM_NORMAL_ISEQ_P(cfp->iseq)) {
            return (rb_control_frame_t *)cfp;
        }
        cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
    }
    return 0;
}

static rb_control_frame_t *
vm_get_ruby_level_caller_cfp(const rb_thread_t *th, const rb_control_frame_t *cfp)
{
    if (RUBY_VM_NORMAL_ISEQ_P(cfp->iseq)) {
        return (rb_control_frame_t *)cfp;
    }

    cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);

    while (!RUBY_VM_CONTROL_FRAME_STACK_OVERFLOW_P(th, cfp)) {
        if (RUBY_VM_NORMAL_ISEQ_P(cfp->iseq)) {
            return (rb_control_frame_t *)cfp;
        }

        if ((cfp->flag & VM_FRAME_FLAG_PASSED) == 0) {
            break;
        }
        cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
    }
    return 0;
}

void
rb_vm_pop_cfunc_frame(void)
{
    rb_thread_t *th = GET_THREAD();
    const rb_callable_method_entry_t *me = rb_vm_frame_method_entry(th->cfp);

    EXEC_EVENT_HOOK(th, RUBY_EVENT_C_RETURN, th->cfp->self, me->called_id, me->owner, Qnil);
    RUBY_DTRACE_CMETHOD_RETURN_HOOK(th, me->owner, me->called_id);
    vm_pop_frame(th);
}

void
rb_vm_rewind_cfp(rb_thread_t *th, rb_control_frame_t *cfp)
{
    /* check skipped frame */
    while (th->cfp != cfp) {
#if VMDEBUG
        printf("skipped frame: %s\n", vm_frametype_name(th->cfp));
#endif
        if (VM_FRAME_TYPE(th->cfp) != VM_FRAME_MAGIC_CFUNC) {
            vm_pop_frame(th);
        }
        else { /* unlikely path */
            rb_vm_pop_cfunc_frame();
        }
    }
}

/* obsolete */
void
rb_frame_pop(void)
{
    ONLY_FOR_INTERNAL_USE("rb_frame_pop()");
}

/* at exit */

void
ruby_vm_at_exit(void (*func)(rb_vm_t *))
{
    rb_vm_t *vm = GET_VM();
    rb_at_exit_list *nl = ALLOC(rb_at_exit_list);
    nl->func = func;
    nl->next = vm->at_exit;
    vm->at_exit = nl;
}

static void
ruby_vm_run_at_exit_hooks(rb_vm_t *vm)
{
    rb_at_exit_list *l = vm->at_exit;

    while (l) {
        rb_at_exit_list* t = l->next;
        rb_vm_at_exit_func *func = l->func;
        free(l);
        l = t;
        (*func)(vm);
    }
}

/* Env */

/*
  env{
    env[0] // special (block or prev env)
    env[1] // env object
  };
 */

static void
env_mark(void * const ptr)
{
    const rb_env_t * const env = ptr;

    /* TODO: should mark more restricted range */
    RUBY_GC_INFO("env->env\n");
    rb_gc_mark_values((long)env->env_size, env->env);

    RUBY_MARK_UNLESS_NULL(rb_vm_env_prev_envval(env));
    RUBY_MARK_UNLESS_NULL(env->block.self);
    RUBY_MARK_UNLESS_NULL(env->block.proc);
    RUBY_MARK_UNLESS_NULL((VALUE)env->block.iseq);
    RUBY_MARK_LEAVE("env");
}

static size_t
env_memsize(const void *ptr)
{
    const rb_env_t * const env = ptr;
    size_t size = sizeof(rb_env_t);

    size += (env->env_size - 1) * sizeof(VALUE);
    return size;
}

static const rb_data_type_t env_data_type = {
    "VM/env",
    {env_mark, RUBY_TYPED_DEFAULT_FREE, env_memsize,},
    0, 0, RUBY_TYPED_FREE_IMMEDIATELY
};

#define VM_EP_IN_HEAP_P(th, ep)   (!((th)->stack <= (ep) && (ep) < ((th)->stack + (th)->stack_size)))
#define VM_ENV_EP_ENVVAL(ep)      ((ep)[1])

static VALUE check_env_value(VALUE envval);

static int
check_env(rb_env_t * const env)
{
    fprintf(stderr, "---\n");
    fprintf(stderr, "envptr: %p\n", (void *)&env->block.ep[0]);
    fprintf(stderr, "envval: %10p ", (void *)env->block.ep[1]);
    dp(env->block.ep[1]);
    fprintf(stderr, "ep:    %10p\n", (void *)env->block.ep);
    if (rb_vm_env_prev_envval(env)) {
        fprintf(stderr, ">>\n");
        check_env_value(rb_vm_env_prev_envval(env));
        fprintf(stderr, "<<\n");
    }
    return 1;
}

static VALUE
check_env_value(VALUE envval)
{
    rb_env_t *env;
    GetEnvPtr(envval, env);

    if (check_env(env)) {
        return envval;
    }
    rb_bug("invalid env");
    return Qnil;                /* unreachable */
}

/* return FALSE if proc was already created */
static int
vm_make_proc_from_block(rb_thread_t *th, rb_block_t *block, VALUE *procptr)
{
    if (!block->proc) {
        *procptr = block->proc = rb_vm_make_proc(th, block, rb_cProc);
        return TRUE;
    }
    else if (SYMBOL_P(block->proc)) {
        *procptr = rb_sym_to_proc(block->proc);
        return TRUE;
    }
    else {
        *procptr = block->proc;
        return FALSE;
    }
}

static VALUE
vm_make_env_each(rb_thread_t *const th, rb_control_frame_t *const cfp)
{
    VALUE envval, blockprocval = 0;
    VALUE * const ep = cfp->ep;
    rb_env_t *env;
    VALUE *new_ep;
    int local_size, env_size;

    if (VM_EP_IN_HEAP_P(th, ep)) {
        return VM_ENV_EP_ENVVAL(ep);
    }

    if (!VM_EP_LEP_P(ep)) {
        VALUE *prev_ep = VM_EP_PREV_EP(ep);

        if (!VM_EP_IN_HEAP_P(th, prev_ep)) {
            rb_control_frame_t *prev_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);

            while (prev_cfp->ep != prev_ep) {
                prev_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(prev_cfp);
                if (VM_CHECK_MODE > 0 && prev_cfp->ep == 0) rb_bug("invalid ep");
            }

            vm_make_env_each(th, prev_cfp);
            *ep = VM_ENVVAL_PREV_EP_PTR(prev_cfp->ep);
        }
    }
    else {
        rb_block_t *block = VM_EP_BLOCK_PTR(ep);

        if (block && vm_make_proc_from_block(th, block, &blockprocval)) {
            rb_proc_t *p;
            GetProcPtr(blockprocval, p);
            *ep = VM_ENVVAL_BLOCK_PTR(&p->block);
        }
    }

    if (!RUBY_VM_NORMAL_ISEQ_P(cfp->iseq)) {
        local_size = 1 /* cref/me */;
    }
    else {
        local_size = cfp->iseq->body->local_size;
    }

    /*
     * # local variables on a stack frame (N == local_size)
     * [lvar1, lvar2, ..., lvarN, SPECVAL]
     *                            ^
     *                            ep[0]
     *
     * # moved local variables
     * [lvar1, lvar2, ..., lvarN, SPECVAL, Envval, BlockProcval (if needed)]
     *  ^                         ^
     *  env->env[0]               ep[0]
     */

    env_size = local_size +
               1 /* specval */ +
               1 /* envval */ +
               (blockprocval ? 1 : 0) /* blockprocval */;

    envval = TypedData_Wrap_Struct(rb_cEnv, &env_data_type, 0);
    env = xmalloc(sizeof(rb_env_t) + (env_size - 1 /* rb_env_t::env[1] */) * sizeof(VALUE));
    env->env_size = env_size;

    MEMCPY(env->env, ep - local_size, VALUE, local_size + 1 /* specval */);

#if 0
    for (i = 0; i < local_size; i++) {
        if (RUBY_VM_NORMAL_ISEQ_P(cfp->iseq)) {
            /* clear value stack for GC */
            ep[-local_size + i] = 0;
        }
    }
#endif

    /* be careful not to trigger GC after this */
    RTYPEDDATA_DATA(envval) = env;

   /*
    * must happen after TypedData_Wrap_Struct to ensure penvval is markable
    * in case object allocation triggers GC and clobbers penvval.
    */
    *ep = envval;               /* GC mark */

    new_ep = &env->env[local_size];
    new_ep[1] = envval;
    if (blockprocval) new_ep[2] = blockprocval;

    /* as Binding */
    env->block.self = cfp->self;
    env->block.ep = cfp->ep = new_ep;
    env->block.iseq = cfp->iseq;
    env->block.proc = 0;

    if (!RUBY_VM_NORMAL_ISEQ_P(cfp->iseq)) {
        /* TODO */
        env->block.iseq = 0;
    }

    return envval;
}

static VALUE
vm_make_env_object(rb_thread_t *th, rb_control_frame_t *cfp)
{
    VALUE envval = vm_make_env_each(th, cfp);

    if (PROCDEBUG) {
        check_env_value(envval);
    }

    return envval;
}

void
rb_vm_stack_to_heap(rb_thread_t *th)
{
    rb_control_frame_t *cfp = th->cfp;
    while ((cfp = rb_vm_get_binding_creatable_next_cfp(th, cfp)) != 0) {
        vm_make_env_object(th, cfp);
        cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
    }
}

VALUE
rb_vm_env_prev_envval(const rb_env_t *env)
{
    const VALUE *ep = env->block.ep;

    if (VM_EP_LEP_P(ep)) {
        return Qfalse;
    }
    else {
        return VM_ENV_EP_ENVVAL(VM_EP_PREV_EP(ep));
    }
}

static int
collect_local_variables_in_iseq(const rb_iseq_t *iseq, const struct local_var_list *vars)
{
    unsigned int i;
    if (!iseq) return 0;
    for (i = 0; i < iseq->body->local_table_size; i++) {
        local_var_list_add(vars, iseq->body->local_table[i]);
    }
    return 1;
}

static void
collect_local_variables_in_env(const rb_env_t *env, const struct local_var_list *vars)
{
    VALUE prev_envval;

    while (collect_local_variables_in_iseq(env->block.iseq, vars), (prev_envval = rb_vm_env_prev_envval(env)) != Qfalse) {
        GetEnvPtr(prev_envval, env);
    }
}

static int
vm_collect_local_variables_in_heap(rb_thread_t *th, const VALUE *ep, const struct local_var_list *vars)
{
    if (VM_EP_IN_HEAP_P(th, ep)) {
        rb_env_t *env;
        GetEnvPtr(VM_ENV_EP_ENVVAL(ep), env);
        collect_local_variables_in_env(env, vars);
        return 1;
    }
    else {
        return 0;
    }
}

VALUE
rb_vm_env_local_variables(const rb_env_t *env)
{
    struct local_var_list vars;
    local_var_list_init(&vars);
    collect_local_variables_in_env(env, &vars);
    return local_var_list_finish(&vars);
}

VALUE
rb_iseq_local_variables(const rb_iseq_t *iseq)
{
    struct local_var_list vars;
    local_var_list_init(&vars);
    while (collect_local_variables_in_iseq(iseq, &vars)) {
        iseq = iseq->body->parent_iseq;
    }
    return local_var_list_finish(&vars);
}

/* Proc */

static inline VALUE
rb_proc_create(VALUE klass, const rb_block_t *block,
               int8_t safe_level, int8_t is_from_method, int8_t is_lambda)
{
    VALUE procval = rb_proc_alloc(klass);
    rb_proc_t *proc = RTYPEDDATA_DATA(procval);

    proc->block = *block;
    proc->block.proc = procval;
    proc->safe_level = safe_level;
    proc->is_from_method = is_from_method;
    proc->is_lambda = is_lambda;

    return procval;
}

VALUE
rb_vm_make_proc(rb_thread_t *th, const rb_block_t *block, VALUE klass)
{
    return rb_vm_make_proc_lambda(th, block, klass, 0);
}

VALUE
rb_vm_make_proc_lambda(rb_thread_t *th, const rb_block_t *block, VALUE klass, int8_t is_lambda)
{
    VALUE procval;
    rb_control_frame_t *cfp = RUBY_VM_GET_CFP_FROM_BLOCK_PTR(block);

    if (block->proc) {
        rb_bug("rb_vm_make_proc: Proc value is already created.");
    }

    vm_make_env_object(th, cfp);
    procval = rb_proc_create(klass, block, (int8_t)th->safe_level, 0, is_lambda);

    if (VMDEBUG) {
        if (th->stack < block->ep && block->ep < th->stack + th->stack_size) {
            rb_bug("invalid ptr: block->ep");
        }
    }

    return procval;
}

VALUE
rb_vm_proc_envval(const rb_proc_t *proc)
{
    VALUE envval = VM_ENV_EP_ENVVAL(proc->block.ep);
    return envval;
}


/* Binding */

VALUE
rb_vm_make_binding(rb_thread_t *th, const rb_control_frame_t *src_cfp)
{
    rb_control_frame_t *cfp = rb_vm_get_binding_creatable_next_cfp(th, src_cfp);
    rb_control_frame_t *ruby_level_cfp = rb_vm_get_ruby_level_next_cfp(th, src_cfp);
    VALUE bindval, envval;
    rb_binding_t *bind;

    if (cfp == 0 || ruby_level_cfp == 0) {
        rb_raise(rb_eRuntimeError, "Can't create Binding Object on top of Fiber.");
    }

    while (1) {
        envval = vm_make_env_object(th, cfp);
        if (cfp == ruby_level_cfp) {
            break;
        }
        cfp = rb_vm_get_binding_creatable_next_cfp(th, RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp));
    }

    bindval = rb_binding_alloc(rb_cBinding);
    GetBindingPtr(bindval, bind);
    bind->env = envval;
    bind->path = ruby_level_cfp->iseq->body->location.path;
    bind->first_lineno = rb_vm_get_sourceline(ruby_level_cfp);

    return bindval;
}

VALUE *
rb_binding_add_dynavars(rb_binding_t *bind, int dyncount, const ID *dynvars)
{
    VALUE envval = bind->env, path = bind->path;
    rb_env_t *env;
    rb_block_t *base_block;
    rb_thread_t *th = GET_THREAD();
    const rb_iseq_t *base_iseq, *iseq;
    NODE *node = 0;
    ID minibuf[4], *dyns = minibuf;
    VALUE idtmp = 0;

    if (dyncount < 0) return 0;

    GetEnvPtr(envval, env);

    base_block = &env->block;
    base_iseq = base_block->iseq;

    if (dyncount >= numberof(minibuf)) dyns = ALLOCV_N(ID, idtmp, dyncount + 1);

    dyns[0] = dyncount;
    MEMCPY(dyns + 1, dynvars, ID, dyncount);
    node = NEW_NODE(NODE_SCOPE, dyns, 0, 0);

    if (base_iseq) {
        iseq = rb_iseq_new(node, base_iseq->body->location.label, path, path, base_iseq, ISEQ_TYPE_EVAL);
    }
    else {
        VALUE tempstr = rb_fstring_cstr("<temp>");
        iseq = rb_iseq_new_top(node, tempstr, tempstr, tempstr, NULL);
    }
    node->u1.tbl = 0; /* reset table */
    ALLOCV_END(idtmp);

    vm_set_eval_stack(th, iseq, 0, base_block);
    bind->env = vm_make_env_object(th, th->cfp);
    vm_pop_frame(th);
    GetEnvPtr(bind->env, env);

    return env->env;
}

/* C -> Ruby: block */

static inline VALUE
invoke_block(rb_thread_t *th, const rb_iseq_t *iseq, VALUE self, const rb_block_t *block, const rb_cref_t *cref, int type, int opt_pc)
{
    int arg_size = iseq->body->param.size;

    vm_push_frame(th, iseq, type | VM_FRAME_FLAG_FINISH, self,
                  VM_ENVVAL_PREV_EP_PTR(block->ep),
                  (VALUE)cref, /* cref or method */
                  iseq->body->iseq_encoded + opt_pc,
                  th->cfp->sp + arg_size, iseq->body->local_size - arg_size,
                  iseq->body->stack_max);

    return vm_exec(th);
}

static VALUE
invoke_bmethod(rb_thread_t *th, const rb_iseq_t *iseq, VALUE self, const rb_block_t *block, int type, int opt_pc)
{
    /* bmethod */
    int arg_size = iseq->body->param.size;
    const rb_callable_method_entry_t *me = th->passed_bmethod_me;
    VALUE ret;

    th->passed_bmethod_me = NULL;

    vm_push_frame(th, iseq, type | VM_FRAME_FLAG_FINISH | VM_FRAME_FLAG_BMETHOD, self,
                  VM_ENVVAL_PREV_EP_PTR(block->ep),
                  (VALUE)me, /* cref or method (TODO: can we ignore cref?) */
                  iseq->body->iseq_encoded + opt_pc,
                  th->cfp->sp + arg_size, iseq->body->local_size - arg_size,
                  iseq->body->stack_max);

    RUBY_DTRACE_METHOD_ENTRY_HOOK(th, me->owner, me->called_id);
    EXEC_EVENT_HOOK(th, RUBY_EVENT_CALL, self, me->called_id, me->owner, Qnil);
    ret = vm_exec(th);
    EXEC_EVENT_HOOK(th, RUBY_EVENT_RETURN, self, me->called_id, me->owner, ret);
    RUBY_DTRACE_METHOD_RETURN_HOOK(th, me->owner, me->called_id);
    return ret;
}

static inline VALUE
invoke_block_from_c_0(rb_thread_t *th, const rb_block_t *block,
                      VALUE self, int argc, const VALUE *argv, const rb_block_t *blockptr,
                      const rb_cref_t *cref, const int splattable)
{
    if (UNLIKELY(!RTEST(block->iseq))) {
        return Qnil;
    }
    else if (LIKELY(RUBY_VM_NORMAL_ISEQ_P(block->iseq))) {
        const rb_iseq_t *iseq = rb_iseq_check(block->iseq);
        int i, opt_pc;
        int type = block_proc_is_lambda(block->proc) ? VM_FRAME_MAGIC_LAMBDA : VM_FRAME_MAGIC_BLOCK;
        VALUE *sp = th->cfp->sp;

        for (i=0; i<argc; i++) {
            sp[i] = argv[i];
        }

        opt_pc = vm_yield_setup_args(th, iseq, argc, sp, blockptr,
                                     (type == VM_FRAME_MAGIC_LAMBDA ? (splattable ? arg_setup_lambda : arg_setup_method) : arg_setup_block));

        if (th->passed_bmethod_me == NULL) {
            return invoke_block(th, iseq, self, block, cref, type, opt_pc);
        }
        else {
            return invoke_bmethod(th, iseq, self, block, type, opt_pc);
        }

    }
    else {
        return vm_yield_with_cfunc(th, block, self, argc, argv, blockptr);
    }
}

static VALUE
invoke_block_from_c_splattable(rb_thread_t *th, const rb_block_t *block,
                               VALUE self, int argc, const VALUE *argv,
                               const rb_block_t *blockptr, const rb_cref_t *cref)
{
    return invoke_block_from_c_0(th, block, self, argc, argv, blockptr, cref, TRUE);
}

static VALUE
invoke_block_from_c_unsplattable(rb_thread_t *th, const rb_block_t *block,
                                 VALUE self, int argc, const VALUE *argv,
                                 const rb_block_t *blockptr, const rb_cref_t *cref)
{
    return invoke_block_from_c_0(th, block, self, argc, argv, blockptr, cref, FALSE);
}


static inline const rb_block_t *
check_block(rb_thread_t *th)
{
    const rb_block_t *blockptr = VM_CF_BLOCK_PTR(th->cfp);

    if (UNLIKELY(blockptr == 0)) {
        rb_vm_localjump_error("no block given", Qnil, 0);
    }

    return blockptr;
}

static VALUE
vm_yield_with_cref(rb_thread_t *th, int argc, const VALUE *argv, const rb_cref_t *cref)
{
    const rb_block_t *blockptr = check_block(th);
    return invoke_block_from_c_splattable(th, blockptr, blockptr->self, argc, argv, NULL, cref);
}

static VALUE
vm_yield(rb_thread_t *th, int argc, const VALUE *argv)
{
    const rb_block_t *blockptr = check_block(th);
    return invoke_block_from_c_splattable(th, blockptr, blockptr->self, argc, argv, NULL, NULL);
}

static VALUE
vm_yield_with_block(rb_thread_t *th, int argc, const VALUE *argv, const rb_block_t *blockargptr)
{
    const rb_block_t *blockptr = check_block(th);
    return invoke_block_from_c_splattable(th, blockptr, blockptr->self, argc, argv, blockargptr, NULL);
}

static VALUE
vm_invoke_proc(rb_thread_t *th, rb_proc_t *proc, VALUE self,
               int argc, const VALUE *argv, const rb_block_t *blockptr)
{
    VALUE val = Qundef;
    int state;
    volatile int stored_safe = th->safe_level;

    TH_PUSH_TAG(th);
    if ((state = EXEC_TAG()) == 0) {
        th->safe_level = proc->safe_level;
        val = invoke_block_from_c_unsplattable(th, &proc->block, self, argc, argv, blockptr, NULL);
    }
    TH_POP_TAG();

    th->safe_level = stored_safe;

    if (state) {
        TH_JUMP_TAG(th, state);
    }
    return val;
}

static VALUE
vm_invoke_bmethod(rb_thread_t *th, rb_proc_t *proc, VALUE self,
                  int argc, const VALUE *argv, const rb_block_t *blockptr)
{
    return invoke_block_from_c_unsplattable(th, &proc->block, self, argc, argv, blockptr, NULL);
}

VALUE
rb_vm_invoke_proc(rb_thread_t *th, rb_proc_t *proc,
                  int argc, const VALUE *argv, const rb_block_t *blockptr)
{
    VALUE self = proc->block.self;
    if (proc->is_from_method) {
        return vm_invoke_bmethod(th, proc, self, argc, argv, blockptr);
    }
    else {
        return vm_invoke_proc(th, proc, self, argc, argv, blockptr);
    }
}

/* special variable */

static rb_control_frame_t *
vm_normal_frame(rb_thread_t *th, rb_control_frame_t *cfp)
{
    while (cfp->pc == 0) {
        cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
        if (RUBY_VM_CONTROL_FRAME_STACK_OVERFLOW_P(th, cfp)) {
            return 0;
        }
    }
    return cfp;
}

static VALUE
vm_cfp_svar_get(rb_thread_t *th, rb_control_frame_t *cfp, VALUE key)
{
    cfp = vm_normal_frame(th, cfp);
    return lep_svar_get(th, cfp ? VM_CF_LEP(cfp) : 0, key);
}

static void
vm_cfp_svar_set(rb_thread_t *th, rb_control_frame_t *cfp, VALUE key, const VALUE val)
{
    cfp = vm_normal_frame(th, cfp);
    lep_svar_set(th, cfp ? VM_CF_LEP(cfp) : 0, key, val);
}

static VALUE
vm_svar_get(VALUE key)
{
    rb_thread_t *th = GET_THREAD();
    return vm_cfp_svar_get(th, th->cfp, key);
}

static void
vm_svar_set(VALUE key, VALUE val)
{
    rb_thread_t *th = GET_THREAD();
    vm_cfp_svar_set(th, th->cfp, key, val);
}

VALUE
rb_backref_get(void)
{
    return vm_svar_get(VM_SVAR_BACKREF);
}

void
rb_backref_set(VALUE val)
{
    vm_svar_set(VM_SVAR_BACKREF, val);
}

VALUE
rb_lastline_get(void)
{
    return vm_svar_get(VM_SVAR_LASTLINE);
}

void
rb_lastline_set(VALUE val)
{
    vm_svar_set(VM_SVAR_LASTLINE, val);
}

/* misc */

VALUE
rb_sourcefilename(void)
{
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);

    if (cfp) {
        return cfp->iseq->body->location.path;
    }
    else {
        return Qnil;
    }
}

const char *
rb_sourcefile(void)
{
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);

    if (cfp) {
        return RSTRING_PTR(cfp->iseq->body->location.path);
    }
    else {
        return 0;
    }
}

int
rb_sourceline(void)
{
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);

    if (cfp) {
        return rb_vm_get_sourceline(cfp);
    }
    else {
        return 0;
    }
}

VALUE
rb_source_location(int *pline)
{
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);

    if (cfp) {
        if (pline) *pline = rb_vm_get_sourceline(cfp);
        return cfp->iseq->body->location.path;
    }
    else {
        if (pline) *pline = 0;
        return 0;
    }
}

const char *
rb_source_loc(int *pline)
{
    VALUE path = rb_source_location(pline);
    if (!path) return 0;
    return RSTRING_PTR(path);
}

rb_cref_t *
rb_vm_cref(void)
{
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);

    if (cfp == NULL) {
        return NULL;
    }

    return rb_vm_get_cref(cfp->ep);
}

rb_cref_t *
rb_vm_cref_replace_with_duplicated_cref(void)
{
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);
    rb_cref_t *cref = vm_cref_replace_with_duplicated_cref(cfp->ep);
    return cref;
}

const rb_cref_t *
rb_vm_cref_in_context(VALUE self, VALUE cbase)
{
    rb_thread_t *th = GET_THREAD();
    const rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);
    const rb_cref_t *cref;
    if (cfp->self != self) return NULL;
    if (!vm_env_cref_by_cref(cfp->ep)) return NULL;
    cref = rb_vm_get_cref(cfp->ep);
    if (CREF_CLASS(cref) != cbase) return NULL;
    return cref;
}

#if 0
void
debug_cref(rb_cref_t *cref)
{
    while (cref) {
        dp(CREF_CLASS(cref));
        printf("%ld\n", CREF_VISI(cref));
        cref = CREF_NEXT(cref);
    }
}
#endif

VALUE
rb_vm_cbase(void)
{
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);

    if (cfp == 0) {
        rb_raise(rb_eRuntimeError, "Can't call on top of Fiber or Thread");
    }
    return vm_get_cbase(cfp->ep);
}

/* jump */

static VALUE
make_localjump_error(const char *mesg, VALUE value, int reason)
{
    extern VALUE rb_eLocalJumpError;
    VALUE exc = rb_exc_new2(rb_eLocalJumpError, mesg);
    ID id;

    switch (reason) {
      case TAG_BREAK:
        CONST_ID(id, "break");
        break;
      case TAG_REDO:
        CONST_ID(id, "redo");
        break;
      case TAG_RETRY:
        CONST_ID(id, "retry");
        break;
      case TAG_NEXT:
        CONST_ID(id, "next");
        break;
      case TAG_RETURN:
        CONST_ID(id, "return");
        break;
      default:
        CONST_ID(id, "noreason");
        break;
    }
    rb_iv_set(exc, "@exit_value", value);
    rb_iv_set(exc, "@reason", ID2SYM(id));
    return exc;
}

void
rb_vm_localjump_error(const char *mesg, VALUE value, int reason)
{
    VALUE exc = make_localjump_error(mesg, value, reason);
    rb_exc_raise(exc);
}

VALUE
rb_vm_make_jump_tag_but_local_jump(int state, VALUE val)
{
    VALUE result = Qnil;

    if (val == Qundef) {
        val = GET_THREAD()->tag->retval;
    }
    switch (state) {
      case 0:
        break;
      case TAG_RETURN:
        result = make_localjump_error("unexpected return", val, state);
        break;
      case TAG_BREAK:
        result = make_localjump_error("unexpected break", val, state);
        break;
      case TAG_NEXT:
        result = make_localjump_error("unexpected next", val, state);
        break;
      case TAG_REDO:
        result = make_localjump_error("unexpected redo", Qnil, state);
        break;
      case TAG_RETRY:
        result = make_localjump_error("retry outside of rescue clause", Qnil, state);
        break;
      default:
        break;
    }
    return result;
}

void
rb_vm_jump_tag_but_local_jump(int state)
{
    VALUE exc = rb_vm_make_jump_tag_but_local_jump(state, Qundef);
    if (!NIL_P(exc)) rb_exc_raise(exc);
    JUMP_TAG(state);
}

NORETURN(static void vm_iter_break(rb_thread_t *th, VALUE val));

static void
vm_iter_break(rb_thread_t *th, VALUE val)
{
    rb_control_frame_t *cfp = th->cfp;
    VALUE *ep = VM_CF_PREV_EP(cfp);
    rb_control_frame_t *target_cfp = rb_vm_search_cf_from_ep(th, cfp, ep);

#if 0                           /* raise LocalJumpError */
    if (!target_cfp) {
        rb_vm_localjump_error("unexpected break", val, TAG_BREAK);
    }
#endif

    th->state = TAG_BREAK;
    th->errinfo = (VALUE)THROW_DATA_NEW(val, target_cfp, TAG_BREAK);
    TH_JUMP_TAG(th, TAG_BREAK);
}

void
rb_iter_break(void)
{
    vm_iter_break(GET_THREAD(), Qnil);
}

void
rb_iter_break_value(VALUE val)
{
    vm_iter_break(GET_THREAD(), val);
}

/* optimization: redefine management */

static st_table *vm_opt_method_table = 0;

static int
vm_redefinition_check_flag(VALUE klass)
{
    if (klass == rb_cInteger) return INTEGER_REDEFINED_OP_FLAG;
    if (klass == rb_cFloat)  return FLOAT_REDEFINED_OP_FLAG;
    if (klass == rb_cString) return STRING_REDEFINED_OP_FLAG;
    if (klass == rb_cArray)  return ARRAY_REDEFINED_OP_FLAG;
    if (klass == rb_cHash)   return HASH_REDEFINED_OP_FLAG;
    if (klass == rb_cSymbol) return SYMBOL_REDEFINED_OP_FLAG;
    if (klass == rb_cTime)   return TIME_REDEFINED_OP_FLAG;
    if (klass == rb_cRegexp) return REGEXP_REDEFINED_OP_FLAG;
    if (klass == rb_cNilClass) return NIL_REDEFINED_OP_FLAG;
    if (klass == rb_cTrueClass) return TRUE_REDEFINED_OP_FLAG;
    if (klass == rb_cFalseClass) return FALSE_REDEFINED_OP_FLAG;
    return 0;
}

static void
rb_vm_check_redefinition_opt_method(const rb_method_entry_t *me, VALUE klass)
{
    st_data_t bop;
    if (RB_TYPE_P(klass, T_ICLASS) && FL_TEST(klass, RICLASS_IS_ORIGIN)) {
       klass = RBASIC_CLASS(klass);
    }
    if (me->def->type == VM_METHOD_TYPE_CFUNC) {
        if (st_lookup(vm_opt_method_table, (st_data_t)me, &bop)) {
            int flag = vm_redefinition_check_flag(klass);

            ruby_vm_redefined_flag[bop] |= flag;
        }
    }
}

static enum rb_id_table_iterator_result
check_redefined_method(ID mid, VALUE value, void *data)
{
    VALUE klass = (VALUE)data;
    const rb_method_entry_t *me = (rb_method_entry_t *)value;
    const rb_method_entry_t *newme = rb_method_entry(klass, mid);

    if (newme != me) rb_vm_check_redefinition_opt_method(me, me->owner);

    return ID_TABLE_CONTINUE;
}

void
rb_vm_check_redefinition_by_prepend(VALUE klass)
{
    if (!vm_redefinition_check_flag(klass)) return;
    rb_id_table_foreach(RCLASS_M_TBL(RCLASS_ORIGIN(klass)), check_redefined_method, (void *)klass);
}

static void
add_opt_method(VALUE klass, ID mid, VALUE bop)
{
    const rb_method_entry_t *me = rb_method_entry_at(klass, mid);

    if (me && me->def->type == VM_METHOD_TYPE_CFUNC) {
        st_insert(vm_opt_method_table, (st_data_t)me, (st_data_t)bop);
    }
    else {
        rb_bug("undefined optimized method: %s", rb_id2name(mid));
    }
}

static void
vm_init_redefined_flag(void)
{
    ID mid;
    VALUE bop;

    vm_opt_method_table = st_init_numtable();

#define OP(mid_, bop_) (mid = id##mid_, bop = BOP_##bop_, ruby_vm_redefined_flag[bop] = 0)
#define C(k) add_opt_method(rb_c##k, mid, bop)
    OP(PLUS, PLUS), (C(Integer), C(Float), C(String), C(Array));
    OP(MINUS, MINUS), (C(Integer), C(Float));
    OP(MULT, MULT), (C(Integer), C(Float));
    OP(DIV, DIV), (C(Integer), C(Float));
    OP(MOD, MOD), (C(Integer), C(Float));
    OP(Eq, EQ), (C(Integer), C(Float), C(String));
    OP(Eqq, EQQ), (C(Integer), C(Float), C(Symbol), C(String),
                   C(NilClass), C(TrueClass), C(FalseClass));
    OP(LT, LT), (C(Integer), C(Float));
    OP(LE, LE), (C(Integer), C(Float));
    OP(GT, GT), (C(Integer), C(Float));
    OP(GE, GE), (C(Integer), C(Float));
    OP(LTLT, LTLT), (C(String), C(Array));
    OP(AREF, AREF), (C(Array), C(Hash));
    OP(ASET, ASET), (C(Array), C(Hash));
    OP(Length, LENGTH), (C(Array), C(String), C(Hash));
    OP(Size, SIZE), (C(Array), C(String), C(Hash));
    OP(EmptyP, EMPTY_P), (C(Array), C(String), C(Hash));
    OP(Succ, SUCC), (C(Integer), C(String), C(Time));
    OP(EqTilde, MATCH), (C(Regexp), C(String));
    OP(Freeze, FREEZE), (C(String));
    OP(Max, MAX), (C(Array));
    OP(Min, MIN), (C(Array));
#undef C
#undef OP
}

/* for vm development */

#if VMDEBUG
static const char *
vm_frametype_name(const rb_control_frame_t *cfp)
{
    switch (VM_FRAME_TYPE(cfp)) {
      case VM_FRAME_MAGIC_METHOD: return "method";
      case VM_FRAME_MAGIC_BLOCK:  return "block";
      case VM_FRAME_MAGIC_CLASS:  return "class";
      case VM_FRAME_MAGIC_TOP:    return "top";
      case VM_FRAME_MAGIC_CFUNC:  return "cfunc";
      case VM_FRAME_MAGIC_PROC:   return "proc";
      case VM_FRAME_MAGIC_IFUNC:  return "ifunc";
      case VM_FRAME_MAGIC_EVAL:   return "eval";
      case VM_FRAME_MAGIC_LAMBDA: return "lambda";
      case VM_FRAME_MAGIC_RESCUE: return "rescue";
      default:
        rb_bug("unknown frame");
    }
}
#endif

static void
hook_before_rewind(rb_thread_t *th, rb_control_frame_t *cfp, int will_finish_vm_exec)
{
    switch (VM_FRAME_TYPE(th->cfp)) {
      case VM_FRAME_MAGIC_METHOD:
        RUBY_DTRACE_METHOD_RETURN_HOOK(th, 0, 0);
        EXEC_EVENT_HOOK_AND_POP_FRAME(th, RUBY_EVENT_RETURN, th->cfp->self, 0, 0, Qnil);
        break;
      case VM_FRAME_MAGIC_BLOCK:
      case VM_FRAME_MAGIC_LAMBDA:
        if (VM_FRAME_TYPE_BMETHOD_P(th->cfp)) {
            EXEC_EVENT_HOOK(th, RUBY_EVENT_B_RETURN, th->cfp->self, 0, 0, Qnil);

            if (!will_finish_vm_exec) {
                /* kick RUBY_EVENT_RETURN at invoke_block_from_c() for bmethod */
                EXEC_EVENT_HOOK_AND_POP_FRAME(th, RUBY_EVENT_RETURN, th->cfp->self,
                                              rb_vm_frame_method_entry(th->cfp)->called_id,
                                              rb_vm_frame_method_entry(th->cfp)->owner, Qnil);
            }
        }
        else {
            EXEC_EVENT_HOOK_AND_POP_FRAME(th, RUBY_EVENT_B_RETURN, th->cfp->self, 0, 0, Qnil);
        }
        break;
      case VM_FRAME_MAGIC_CLASS:
        EXEC_EVENT_HOOK_AND_POP_FRAME(th, RUBY_EVENT_END, th->cfp->self, 0, 0, Qnil);
        break;
    }
}

/* evaluator body */

/*                  finish
  VMe (h1)          finish
    VM              finish F1 F2
      cfunc         finish F1 F2 C1
        rb_funcall  finish F1 F2 C1
          VMe       finish F1 F2 C1
            VM      finish F1 F2 C1 F3

  F1 - F3 : pushed by VM
  C1      : pushed by send insn (CFUNC)

  struct CONTROL_FRAME {
    VALUE *pc;                  // cfp[0], program counter
    VALUE *sp;                  // cfp[1], stack pointer
    VALUE *bp;                  // cfp[2], base pointer
    rb_iseq_t *iseq;            // cfp[3], iseq
    VALUE flag;                 // cfp[4], magic
    VALUE self;                 // cfp[5], self
    VALUE *ep;                  // cfp[6], env pointer
    rb_iseq_t * block_iseq;     // cfp[7], block iseq
    VALUE proc;                 // cfp[8], always 0
  };

  struct BLOCK {
    VALUE self;
    VALUE *ep;
    rb_iseq_t *block_iseq;
    VALUE proc;
  };

  struct METHOD_CONTROL_FRAME {
    rb_control_frame_t frame;
  };

  struct METHOD_FRAME {
    VALUE arg0;
    ...
    VALUE argM;
    VALUE param0;
    ...
    VALUE paramN;
    VALUE cref;
    VALUE special;                         // lep [1]
    struct block_object *block_ptr | 0x01; // lep [0]
  };

  struct BLOCK_CONTROL_FRAME {
    rb_control_frame_t frame;
  };

  struct BLOCK_FRAME {
    VALUE arg0;
    ...
    VALUE argM;
    VALUE param0;
    ...
    VALUE paramN;
    VALUE cref;
    VALUE *(prev_ptr | 0x01); // ep[0]
  };

  struct CLASS_CONTROL_FRAME {
    rb_control_frame_t frame;
  };

  struct CLASS_FRAME {
    VALUE param0;
    ...
    VALUE paramN;
    VALUE cref;
    VALUE prev_ep; // for frame jump
  };

  struct C_METHOD_CONTROL_FRAME {
    VALUE *pc;                       // 0
    VALUE *sp;                       // stack pointer
    VALUE *bp;                       // base pointer (used in exception)
    rb_iseq_t *iseq;                 // cmi
    VALUE magic;                     // C_METHOD_FRAME
    VALUE self;                      // ?
    VALUE *ep;                       // ep == lep
    rb_iseq_t * block_iseq;          //
    VALUE proc;                      // always 0
  };

  struct C_BLOCK_CONTROL_FRAME {
    VALUE *pc;                       // point only "finish" insn
    VALUE *sp;                       // sp
    rb_iseq_t *iseq;                 // ?
    VALUE magic;                     // C_METHOD_FRAME
    VALUE self;                      // needed?
    VALUE *ep;                       // ep
    rb_iseq_t * block_iseq; // 0
  };
 */

static VALUE
vm_exec(rb_thread_t *th)
{
    int state;
    VALUE result;
    VALUE initial = 0;
    struct vm_throw_data *err;

    TH_PUSH_TAG(th);
    _tag.retval = Qnil;
    if ((state = EXEC_TAG()) == 0) {
      vm_loop_start:
        result = vm_exec_core(th, initial);
        if ((state = th->state) != 0) {
            err = (struct vm_throw_data *)result;
            th->state = 0;
            goto exception_handler;
        }
    }
    else {
        unsigned int i;
        const struct iseq_catch_table_entry *entry;
        const struct iseq_catch_table *ct;
        unsigned long epc, cont_pc, cont_sp;
        const rb_iseq_t *catch_iseq;
        rb_control_frame_t *cfp;
        VALUE type;
        const rb_control_frame_t *escape_cfp;

        err = (struct vm_throw_data *)th->errinfo;

      exception_handler:
        cont_pc = cont_sp = 0;
        catch_iseq = NULL;

        while (th->cfp->pc == 0 || th->cfp->iseq == 0) {
            if (UNLIKELY(VM_FRAME_TYPE(th->cfp) == VM_FRAME_MAGIC_CFUNC)) {
                EXEC_EVENT_HOOK(th, RUBY_EVENT_C_RETURN, th->cfp->self,
                                rb_vm_frame_method_entry(th->cfp)->called_id,
                                rb_vm_frame_method_entry(th->cfp)->owner, Qnil);
                RUBY_DTRACE_CMETHOD_RETURN_HOOK(th,
                                               rb_vm_frame_method_entry(th->cfp)->owner,
                                               rb_vm_frame_method_entry(th->cfp)->called_id);
            }
            th->cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(th->cfp);
        }

        cfp = th->cfp;
        epc = cfp->pc - cfp->iseq->body->iseq_encoded;

        escape_cfp = NULL;
        if (state == TAG_BREAK || state == TAG_RETURN) {
            escape_cfp = THROW_DATA_CATCH_FRAME(err);

            if (cfp == escape_cfp) {
                if (state == TAG_RETURN) {
                    if (!VM_FRAME_TYPE_FINISH_P(cfp)) {
                        THROW_DATA_CATCH_FRAME_SET(err, cfp + 1);
                        THROW_DATA_STATE_SET(err, state = TAG_BREAK);
                    }
                    else {
                        ct = cfp->iseq->body->catch_table;
                        if (ct) for (i = 0; i < ct->size; i++) {
                            entry = &ct->entries[i];
                            if (entry->start < epc && entry->end >= epc) {
                                if (entry->type == CATCH_TYPE_ENSURE) {
                                    catch_iseq = entry->iseq;
                                    cont_pc = entry->cont;
                                    cont_sp = entry->sp;
                                    break;
                                }
                            }
                        }
                        if (!catch_iseq) {
                            th->errinfo = Qnil;
                            result = THROW_DATA_VAL(err);
                            hook_before_rewind(th, th->cfp, TRUE);
                            vm_pop_frame(th);
                            goto finish_vme;
                        }
                    }
                    /* through */
                }
                else {
                    /* TAG_BREAK */
#if OPT_STACK_CACHING
                    initial = THROW_DATA_VAL(err);
#else
                    *th->cfp->sp++ = THROW_DATA_VAL(err);
#endif
                    th->errinfo = Qnil;
                    goto vm_loop_start;
                }
            }
        }

        if (state == TAG_RAISE) {
            ct = cfp->iseq->body->catch_table;
            if (ct) for (i = 0; i < ct->size; i++) {
                entry = &ct->entries[i];
                if (entry->start < epc && entry->end >= epc) {

                    if (entry->type == CATCH_TYPE_RESCUE ||
                        entry->type == CATCH_TYPE_ENSURE) {
                        catch_iseq = entry->iseq;
                        cont_pc = entry->cont;
                        cont_sp = entry->sp;
                        break;
                    }
                }
            }
        }
        else if (state == TAG_RETRY) {
            ct = cfp->iseq->body->catch_table;
            if (ct) for (i = 0; i < ct->size; i++) {
                entry = &ct->entries[i];
                if (entry->start < epc && entry->end >= epc) {

                    if (entry->type == CATCH_TYPE_ENSURE) {
                        catch_iseq = entry->iseq;
                        cont_pc = entry->cont;
                        cont_sp = entry->sp;
                        break;
                    }
                    else if (entry->type == CATCH_TYPE_RETRY) {
                        const rb_control_frame_t *escape_cfp;
                        escape_cfp = THROW_DATA_CATCH_FRAME(err);
                        if (cfp == escape_cfp) {
                            cfp->pc = cfp->iseq->body->iseq_encoded + entry->cont;
                            th->errinfo = Qnil;
                            goto vm_loop_start;
                        }
                    }
                }
            }
        }
        else if (state == TAG_BREAK && !escape_cfp) {
            type = CATCH_TYPE_BREAK;

          search_restart_point:
            ct = cfp->iseq->body->catch_table;
            if (ct) for (i = 0; i < ct->size; i++) {
                entry = &ct->entries[i];

                if (entry->start < epc && entry->end >= epc) {
                    if (entry->type == CATCH_TYPE_ENSURE) {
                        catch_iseq = entry->iseq;
                        cont_pc = entry->cont;
                        cont_sp = entry->sp;
                        break;
                    }
                    else if (entry->type == type) {
                        cfp->pc = cfp->iseq->body->iseq_encoded + entry->cont;
                        cfp->sp = vm_base_ptr(cfp) + entry->sp;

                        if (state != TAG_REDO) {
#if OPT_STACK_CACHING
                            initial = THROW_DATA_VAL(err);
#else
                            *th->cfp->sp++ = THROW_DATA_VAL(err);
#endif
                        }
                        th->errinfo = Qnil;
                        th->state = 0;
                        goto vm_loop_start;
                    }
                }
            }
        }
        else if (state == TAG_REDO) {
            type = CATCH_TYPE_REDO;
            goto search_restart_point;
        }
        else if (state == TAG_NEXT) {
            type = CATCH_TYPE_NEXT;
            goto search_restart_point;
        }
        else {
            ct = cfp->iseq->body->catch_table;
            if (ct) for (i = 0; i < ct->size; i++) {
                entry = &ct->entries[i];
                if (entry->start < epc && entry->end >= epc) {

                    if (entry->type == CATCH_TYPE_ENSURE) {
                        catch_iseq = entry->iseq;
                        cont_pc = entry->cont;
                        cont_sp = entry->sp;
                        break;
                    }
                }
            }
        }

        if (catch_iseq != NULL) { /* found catch table */
            /* enter catch scope */
            rb_iseq_check(catch_iseq);
            cfp->sp = vm_base_ptr(cfp) + cont_sp;
            cfp->pc = cfp->iseq->body->iseq_encoded + cont_pc;

            /* push block frame */
            cfp->sp[0] = (VALUE)err;
            vm_push_frame(th, catch_iseq, VM_FRAME_MAGIC_RESCUE,
                          cfp->self,
                          VM_ENVVAL_PREV_EP_PTR(cfp->ep),
                          0, /* cref or me */
                          catch_iseq->body->iseq_encoded,
                          cfp->sp + 1 /* push value */,
                          catch_iseq->body->local_size - 1,
                          catch_iseq->body->stack_max);

            state = 0;
            th->state = 0;
            th->errinfo = Qnil;
            goto vm_loop_start;
        }
        else {
            /* skip frame */
            hook_before_rewind(th, th->cfp, FALSE);

            if (VM_FRAME_TYPE_FINISH_P(th->cfp)) {
                vm_pop_frame(th);
                th->errinfo = (VALUE)err;
                TH_TMPPOP_TAG();
                TH_JUMP_TAG(th, state);
            }
            else {
                th->cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(th->cfp);
                goto exception_handler;
            }
        }
    }
  finish_vme:
    TH_POP_TAG();
    return result;
}

/* misc */

VALUE
rb_iseq_eval(const rb_iseq_t *iseq)
{
    rb_thread_t *th = GET_THREAD();
    VALUE val;
    vm_set_top_stack(th, iseq);
    val = vm_exec(th);
    return val;
}

VALUE
rb_iseq_eval_main(const rb_iseq_t *iseq)
{
    rb_thread_t *th = GET_THREAD();
    VALUE val;

    vm_set_main_stack(th, iseq);
    val = vm_exec(th);
    return val;
}

int
rb_vm_control_frame_id_and_class(const rb_control_frame_t *cfp, ID *idp, VALUE *klassp)
{
    const rb_callable_method_entry_t *me = rb_vm_frame_method_entry(cfp);

    if (me) {
        if (idp) *idp = me->def->original_id;
        if (klassp) *klassp = me->owner;
        return TRUE;
    }
    else {
        return FALSE;
    }
}

int
rb_thread_method_id_and_class(rb_thread_t *th, ID *idp, VALUE *klassp)
{
    return rb_vm_control_frame_id_and_class(th->cfp, idp, klassp);
}

int
rb_frame_method_id_and_class(ID *idp, VALUE *klassp)
{
    return rb_thread_method_id_and_class(GET_THREAD(), idp, klassp);
}

VALUE
rb_thread_current_status(const rb_thread_t *th)
{
    const rb_control_frame_t *cfp = th->cfp;
    const rb_callable_method_entry_t *me;
    VALUE str = Qnil;

    if (cfp->iseq != 0) {
        if (cfp->pc != 0) {
            const rb_iseq_t *iseq = cfp->iseq;
            int line_no = rb_vm_get_sourceline(cfp);
            str = rb_sprintf("%"PRIsVALUE":%d:in `%"PRIsVALUE"'",
                             iseq->body->location.path, line_no, iseq->body->location.label);
        }
    }
    else if ((me = rb_vm_frame_method_entry(cfp)) && me->def->original_id) {
        str = rb_sprintf("`%"PRIsVALUE"#%"PRIsVALUE"' (cfunc)",
                         rb_class_path(me->owner),
                         rb_id2str(me->def->original_id));
    }

    return str;
}

VALUE
rb_vm_call_cfunc(VALUE recv, VALUE (*func)(VALUE), VALUE arg,
                 const rb_block_t *blockptr, VALUE filename)
{
    rb_thread_t *th = GET_THREAD();
    const rb_control_frame_t *reg_cfp = th->cfp;
    const rb_iseq_t *iseq = rb_iseq_new(0, filename, filename, Qnil, 0, ISEQ_TYPE_TOP);
    VALUE val;

    vm_push_frame(th, iseq, VM_FRAME_MAGIC_TOP | VM_FRAME_FLAG_FINISH,
                  recv, VM_ENVVAL_BLOCK_PTR(blockptr),
                  (VALUE)vm_cref_new_toplevel(th), /* cref or me */
                  0, reg_cfp->sp, 1, 0);

    val = (*func)(arg);

    vm_pop_frame(th);
    return val;
}

/* vm */

void rb_vm_trace_mark_event_hooks(rb_hook_list_t *hooks);

void
rb_vm_mark(void *ptr)
{
    int i;

    RUBY_MARK_ENTER("vm");
    RUBY_GC_INFO("-------------------------------------------------\n");
    if (ptr) {
        rb_vm_t *vm = ptr;
        rb_thread_t *th = 0;

        list_for_each(&vm->living_threads, th, vmlt_node) {
            rb_gc_mark(th->self);
        }
        rb_gc_mark(vm->thgroup_default);
        rb_gc_mark(vm->mark_object_ary);
        rb_gc_mark(vm->load_path);
        rb_gc_mark(vm->load_path_snapshot);
        RUBY_MARK_UNLESS_NULL(vm->load_path_check_cache);
        rb_gc_mark(vm->expanded_load_path);
        rb_gc_mark(vm->loaded_features);
        rb_gc_mark(vm->loaded_features_snapshot);
        rb_gc_mark(vm->top_self);
        RUBY_MARK_UNLESS_NULL(vm->coverages);
        rb_gc_mark(vm->defined_module_hash);

        if (vm->loading_table) {
            rb_mark_tbl(vm->loading_table);
        }

        rb_vm_trace_mark_event_hooks(&vm->event_hooks);

        for (i = 0; i < RUBY_NSIG; i++) {
            if (vm->trap_list[i].cmd)
                rb_gc_mark(vm->trap_list[i].cmd);
        }
    }

    RUBY_MARK_LEAVE("vm");
}

void
rb_vm_register_special_exception(enum ruby_special_exceptions sp, VALUE cls, const char *mesg)
{
    rb_vm_t *vm = GET_VM();
    VALUE exc = rb_exc_new3(cls, rb_obj_freeze(rb_str_new2(mesg)));
    OBJ_TAINT(exc);
    OBJ_FREEZE(exc);
    ((VALUE *)vm->special_exceptions)[sp] = exc;
    rb_gc_register_mark_object(exc);
}

int
rb_vm_add_root_module(ID id, VALUE module)
{
    rb_vm_t *vm = GET_VM();

    rb_hash_aset(vm->defined_module_hash, ID2SYM(id), module);

    return TRUE;
}

static int
free_loading_table_entry(st_data_t key, st_data_t value, st_data_t arg)
{
    xfree((char *)key);
    return ST_DELETE;
}

int
ruby_vm_destruct(rb_vm_t *vm)
{
    RUBY_FREE_ENTER("vm");

    if (vm) {
        rb_thread_t *th = vm->main_thread;
        struct rb_objspace *objspace = vm->objspace;
        vm->main_thread = 0;
        if (th) {
            rb_fiber_reset_root_local_storage(th->self);
            thread_free(th);
        }
        rb_vm_living_threads_init(vm);
        ruby_vm_run_at_exit_hooks(vm);
        if (vm->loading_table) {
            st_foreach(vm->loading_table, free_loading_table_entry, 0);
            st_free_table(vm->loading_table);
            vm->loading_table = 0;
        }
        if (vm->frozen_strings) {
            st_free_table(vm->frozen_strings);
            vm->frozen_strings = 0;
        }
        rb_vm_gvl_destroy(vm);
        if (objspace) {
            rb_objspace_free(objspace);
        }
        /* after freeing objspace, you *can't* use ruby_xfree() */
        ruby_mimfree(vm);
        ruby_current_vm = 0;
    }
    RUBY_FREE_LEAVE("vm");
    return 0;
}

static size_t
vm_memsize(const void *ptr)
{
    const rb_vm_t *vmobj = ptr;
    size_t size = sizeof(rb_vm_t);

    size += vmobj->living_thread_num * sizeof(rb_thread_t);

    if (vmobj->defined_strings) {
        size += DEFINED_EXPR * sizeof(VALUE);
    }
    return size;
}

static const rb_data_type_t vm_data_type = {
    "VM",
    {NULL, NULL, vm_memsize,},
    0, 0, RUBY_TYPED_FREE_IMMEDIATELY
};


static VALUE
vm_default_params(void)
{
    rb_vm_t *vm = GET_VM();
    VALUE result = rb_hash_new();
#define SET(name) rb_hash_aset(result, ID2SYM(rb_intern(#name)), SIZET2NUM(vm->default_params.name));
    SET(thread_vm_stack_size);
    SET(thread_machine_stack_size);
    SET(fiber_vm_stack_size);
    SET(fiber_machine_stack_size);
#undef SET
    rb_obj_freeze(result);
    return result;
}

static size_t
get_param(const char *name, size_t default_value, size_t min_value)
{
    const char *envval;
    size_t result = default_value;
    if ((envval = getenv(name)) != 0) {
        long val = atol(envval);
        if (val < (long)min_value) {
            val = (long)min_value;
        }
        result = (size_t)(((val -1 + RUBY_VM_SIZE_ALIGN) / RUBY_VM_SIZE_ALIGN) * RUBY_VM_SIZE_ALIGN);
    }
    if (0) fprintf(stderr, "%s: %"PRIdSIZE"\n", name, result); /* debug print */

    return result;
}

static void
check_machine_stack_size(size_t *sizep)
{
#ifdef PTHREAD_STACK_MIN
    size_t size = *sizep;
#endif

#ifdef PTHREAD_STACK_MIN
    if (size < PTHREAD_STACK_MIN) {
        *sizep = PTHREAD_STACK_MIN * 2;
    }
#endif
}

static void
vm_default_params_setup(rb_vm_t *vm)
{
    vm->default_params.thread_vm_stack_size =
      get_param("RUBY_THREAD_VM_STACK_SIZE",
                RUBY_VM_THREAD_VM_STACK_SIZE,
                RUBY_VM_THREAD_VM_STACK_SIZE_MIN);

    vm->default_params.thread_machine_stack_size =
      get_param("RUBY_THREAD_MACHINE_STACK_SIZE",
                RUBY_VM_THREAD_MACHINE_STACK_SIZE,
                RUBY_VM_THREAD_MACHINE_STACK_SIZE_MIN);

    vm->default_params.fiber_vm_stack_size =
      get_param("RUBY_FIBER_VM_STACK_SIZE",
                RUBY_VM_FIBER_VM_STACK_SIZE,
                RUBY_VM_FIBER_VM_STACK_SIZE_MIN);

    vm->default_params.fiber_machine_stack_size =
      get_param("RUBY_FIBER_MACHINE_STACK_SIZE",
                RUBY_VM_FIBER_MACHINE_STACK_SIZE,
                RUBY_VM_FIBER_MACHINE_STACK_SIZE_MIN);

    /* environment dependent check */
    check_machine_stack_size(&vm->default_params.thread_machine_stack_size);
    check_machine_stack_size(&vm->default_params.fiber_machine_stack_size);
}

static void
vm_init2(rb_vm_t *vm)
{
    MEMZERO(vm, rb_vm_t, 1);
    rb_vm_living_threads_init(vm);
    vm->src_encoding_index = -1;

    vm_default_params_setup(vm);
}

/* Thread */

#define USE_THREAD_DATA_RECYCLE 1

#if USE_THREAD_DATA_RECYCLE
#define RECYCLE_MAX 64
static VALUE *thread_recycle_stack_slot[RECYCLE_MAX];
static int thread_recycle_stack_count = 0;

static VALUE *
thread_recycle_stack(size_t size)
{
    if (thread_recycle_stack_count) {
        /* TODO: check stack size if stack sizes are variable */
        return thread_recycle_stack_slot[--thread_recycle_stack_count];
    }
    else {
        return ALLOC_N(VALUE, size);
    }
}

#else
#define thread_recycle_stack(size) ALLOC_N(VALUE, (size))
#endif

void
rb_thread_recycle_stack_release(VALUE *stack)
{
#if USE_THREAD_DATA_RECYCLE
    if (thread_recycle_stack_count < RECYCLE_MAX) {
        thread_recycle_stack_slot[thread_recycle_stack_count++] = stack;
        return;
    }
#endif
    ruby_xfree(stack);
}

void rb_fiber_mark_self(rb_fiber_t *fib);

void
rb_thread_mark(void *ptr)
{
    rb_thread_t *th = ptr;
    RUBY_MARK_ENTER("thread");

    if (th->stack) {
        VALUE *p = th->stack;
        VALUE *sp = th->cfp->sp;
        rb_control_frame_t *cfp = th->cfp;
        rb_control_frame_t *limit_cfp = (void *)(th->stack + th->stack_size);

        rb_gc_mark_values((long)(sp - p), p);

        while (cfp != limit_cfp) {
            rb_gc_mark(cfp->proc);
            rb_gc_mark(cfp->self);
            rb_gc_mark((VALUE)cfp->iseq);
            cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
        }
    }

    /* mark ruby objects */
    RUBY_MARK_UNLESS_NULL(th->first_proc);
    if (th->first_proc) RUBY_MARK_UNLESS_NULL(th->first_args);

    RUBY_MARK_UNLESS_NULL(th->thgroup);
    RUBY_MARK_UNLESS_NULL(th->value);
    RUBY_MARK_UNLESS_NULL(th->errinfo);
    RUBY_MARK_UNLESS_NULL(th->pending_interrupt_queue);
    RUBY_MARK_UNLESS_NULL(th->pending_interrupt_mask_stack);
    RUBY_MARK_UNLESS_NULL(th->root_svar);
    RUBY_MARK_UNLESS_NULL(th->top_self);
    RUBY_MARK_UNLESS_NULL(th->top_wrapper);
    rb_fiber_mark_self(th->fiber);
    rb_fiber_mark_self(th->root_fiber);
    RUBY_MARK_UNLESS_NULL(th->stat_insn_usage);
    RUBY_MARK_UNLESS_NULL(th->last_status);

    RUBY_MARK_UNLESS_NULL(th->locking_mutex);

    rb_mark_tbl(th->local_storage);
    RUBY_MARK_UNLESS_NULL(th->local_storage_recursive_hash);
    RUBY_MARK_UNLESS_NULL(th->local_storage_recursive_hash_for_trace);

    if (GET_THREAD() != th && th->machine.stack_start && th->machine.stack_end) {
        rb_gc_mark_machine_stack(th);
        rb_gc_mark_locations((VALUE *)&th->machine.regs,
                             (VALUE *)(&th->machine.regs) +
                             sizeof(th->machine.regs) / sizeof(VALUE));
    }

    RUBY_MARK_UNLESS_NULL(th->name);

    rb_vm_trace_mark_event_hooks(&th->event_hooks);

    RUBY_MARK_LEAVE("thread");
}

static void
thread_free(void *ptr)
{
    rb_thread_t *th;
    RUBY_FREE_ENTER("thread");

    if (ptr) {
        th = ptr;

        if (!th->root_fiber) {
            RUBY_FREE_UNLESS_NULL(th->stack);
        }

        if (th->locking_mutex != Qfalse) {
            rb_bug("thread_free: locking_mutex must be NULL (%p:%p)", (void *)th, (void *)th->locking_mutex);
        }
        if (th->keeping_mutexes != NULL) {
            rb_bug("thread_free: keeping_mutexes must be NULL (%p:%p)", (void *)th, (void *)th->keeping_mutexes);
        }

        if (th->local_storage) {
            st_free_table(th->local_storage);
        }

        if (th->vm && th->vm->main_thread == th) {
            RUBY_GC_INFO("main thread\n");
        }
        else {
#ifdef USE_SIGALTSTACK
            if (th->altstack) {
                free(th->altstack);
            }
#endif
            ruby_xfree(ptr);
        }
        if (ruby_current_thread == th)
            ruby_current_thread = NULL;
    }
    RUBY_FREE_LEAVE("thread");
}

static size_t
thread_memsize(const void *ptr)
{
    const rb_thread_t *th = ptr;
    size_t size = sizeof(rb_thread_t);

    if (!th->root_fiber) {
        size += th->stack_size * sizeof(VALUE);
    }
    if (th->local_storage) {
        size += st_memsize(th->local_storage);
    }
    return size;
}

#define thread_data_type ruby_threadptr_data_type
const rb_data_type_t ruby_threadptr_data_type = {
    "VM/thread",
    {
        rb_thread_mark,
        thread_free,
        thread_memsize,
    },
    0, 0, RUBY_TYPED_FREE_IMMEDIATELY
};

VALUE
rb_obj_is_thread(VALUE obj)
{
    if (rb_typeddata_is_kind_of(obj, &thread_data_type)) {
        return Qtrue;
    }
    else {
        return Qfalse;
    }
}

static VALUE
thread_alloc(VALUE klass)
{
    VALUE obj;
    rb_thread_t *th;
    obj = TypedData_Make_Struct(klass, rb_thread_t, &thread_data_type, th);

    return obj;
}

static void
th_init(rb_thread_t *th, VALUE self)
{
    th->self = self;

    /* allocate thread stack */
#ifdef USE_SIGALTSTACK
    /* altstack of main thread is reallocated in another place */
    th->altstack = malloc(rb_sigaltstack_size());
#endif
    /* th->stack_size is word number.
     * th->vm->default_params.thread_vm_stack_size is byte size.
     */
    th->stack_size = th->vm->default_params.thread_vm_stack_size / sizeof(VALUE);
    th->stack = thread_recycle_stack(th->stack_size);

    th->cfp = (void *)(th->stack + th->stack_size);

    vm_push_frame(th, 0 /* dummy iseq */, VM_FRAME_MAGIC_DUMMY | VM_FRAME_FLAG_FINISH /* dummy frame */,
                  Qnil /* dummy self */, VM_ENVVAL_BLOCK_PTR(0) /* dummy block ptr */,
                  0 /* dummy cref/me */,
                  0 /* dummy pc */, th->stack, 1, 0);

    th->status = THREAD_RUNNABLE;
    th->errinfo = Qnil;
    th->last_status = Qnil;
    th->waiting_fd = -1;
    th->root_svar = Qfalse;
    th->local_storage_recursive_hash = Qnil;
    th->local_storage_recursive_hash_for_trace = Qnil;
#ifdef NON_SCALAR_THREAD_ID
    th->thread_id_string[0] = '\0';
#endif

#if OPT_CALL_THREADED_CODE
    th->retval = Qundef;
#endif
    th->name = Qnil;
}

static VALUE
ruby_thread_init(VALUE self)
{
    rb_thread_t *th;
    rb_vm_t *vm = GET_THREAD()->vm;
    GetThreadPtr(self, th);

    th->vm = vm;
    th_init(th, self);
    rb_ivar_set(self, rb_intern("locals"), rb_hash_new());

    th->top_wrapper = 0;
    th->top_self = rb_vm_top_self();
    th->root_svar = Qfalse;
    return self;
}

VALUE
rb_thread_alloc(VALUE klass)
{
    VALUE self = thread_alloc(klass);
    ruby_thread_init(self);
    return self;
}

static void
vm_define_method(rb_thread_t *th, VALUE obj, ID id, VALUE iseqval, int is_singleton)
{
    VALUE klass;
    rb_method_visibility_t visi;
    rb_cref_t *cref = rb_vm_cref();

    if (!is_singleton) {
        klass = CREF_CLASS(cref);
        visi = rb_scope_visibility_get();
    }
    else { /* singleton */
        klass = rb_singleton_class(obj); /* class and frozen checked in this API */
        visi = METHOD_VISI_PUBLIC;
    }

    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 && rb_scope_module_func_check()) {
        klass = rb_singleton_class(klass);
        rb_add_method_iseq(klass, id, (const rb_iseq_t *)iseqval, cref, METHOD_VISI_PUBLIC);
    }
}

#define REWIND_CFP(expr) do { \
    rb_thread_t *th__ = GET_THREAD(); \
    VALUE *const curr_sp = (th__->cfp++)->sp; \
    VALUE *const saved_sp = th__->cfp->sp; \
    th__->cfp->sp = curr_sp; \
    expr; \
    (th__->cfp--)->sp = saved_sp; \
} while (0)

static VALUE
m_core_define_method(VALUE self, VALUE sym, VALUE iseqval)
{
    REWIND_CFP({
        vm_define_method(GET_THREAD(), Qnil, SYM2ID(sym), iseqval, FALSE);
    });
    return sym;
}

static VALUE
m_core_define_singleton_method(VALUE self, VALUE cbase, VALUE sym, VALUE iseqval)
{
    REWIND_CFP({
        vm_define_method(GET_THREAD(), cbase, SYM2ID(sym), iseqval, TRUE);
    });
    return sym;
}

static VALUE
m_core_set_method_alias(VALUE self, VALUE cbase, VALUE sym1, VALUE sym2)
{
    REWIND_CFP({
        rb_alias(cbase, SYM2ID(sym1), SYM2ID(sym2));
    });
    return Qnil;
}

static VALUE
m_core_set_variable_alias(VALUE self, VALUE sym1, VALUE sym2)
{
    REWIND_CFP({
        rb_alias_variable(SYM2ID(sym1), SYM2ID(sym2));
    });
    return Qnil;
}

static VALUE
m_core_undef_method(VALUE self, VALUE cbase, VALUE sym)
{
    REWIND_CFP({
        rb_undef(cbase, SYM2ID(sym));
        rb_clear_method_cache_by_class(self);
    });
    return Qnil;
}

static VALUE
m_core_set_postexe(VALUE self)
{
    rb_set_end_proc(rb_call_end_proc, rb_block_proc());
    return Qnil;
}

static VALUE core_hash_merge_ary(VALUE hash, VALUE ary);
static VALUE core_hash_from_ary(VALUE ary);
static VALUE core_hash_merge_kwd(int argc, VALUE *argv);

static VALUE
core_hash_merge(VALUE hash, long argc, const VALUE *argv)
{
    long i;

    VM_ASSERT(argc % 2 == 0);
    for (i=0; i<argc; i+=2) {
        rb_hash_aset(hash, argv[i], argv[i+1]);
    }
    return hash;
}

static VALUE
m_core_hash_from_ary(VALUE self, VALUE ary)
{
    VALUE hash;
    REWIND_CFP(hash = core_hash_from_ary(ary));
    return hash;
}

static VALUE
core_hash_from_ary(VALUE ary)
{
    VALUE hash = rb_hash_new();

    RUBY_DTRACE_CREATE_HOOK(HASH, RARRAY_LEN(ary));
    return core_hash_merge_ary(hash, ary);
}

static VALUE
m_core_hash_merge_ary(VALUE self, VALUE hash, VALUE ary)
{
    REWIND_CFP(core_hash_merge_ary(hash, ary));
    return hash;
}

static VALUE
core_hash_merge_ary(VALUE hash, VALUE ary)
{
    core_hash_merge(hash, RARRAY_LEN(ary), RARRAY_CONST_PTR(ary));
    return hash;
}

static VALUE
m_core_hash_merge_ptr(int argc, VALUE *argv, VALUE recv)
{
    VALUE hash = argv[0];

    REWIND_CFP(core_hash_merge(hash, argc-1, argv+1));

    return hash;
}

static int
kwmerge_i(VALUE key, VALUE value, VALUE hash)
{
    if (!SYMBOL_P(key)) Check_Type(key, T_SYMBOL);
    rb_hash_aset(hash, key, value);
    return ST_CONTINUE;
}

static int
kwcheck_i(VALUE key, VALUE value, VALUE hash)
{
    if (!SYMBOL_P(key)) Check_Type(key, T_SYMBOL);
    return ST_CONTINUE;
}

static VALUE
m_core_hash_merge_kwd(int argc, VALUE *argv, VALUE recv)
{
    VALUE hash;
    REWIND_CFP(hash = core_hash_merge_kwd(argc, argv));
    return hash;
}

static VALUE
core_hash_merge_kwd(int argc, VALUE *argv)
{
    VALUE hash, kw;
    rb_check_arity(argc, 1, 2);
    hash = argv[0];
    kw = argv[argc-1];
    kw = rb_convert_type(kw, T_HASH, "Hash", "to_hash");
    if (argc < 2) hash = kw;
    rb_hash_foreach(kw, argc < 2 ? kwcheck_i : kwmerge_i, hash);
    return hash;
}

extern VALUE *rb_gc_stack_start;
extern size_t rb_gc_stack_maxsize;
#ifdef __ia64
extern VALUE *rb_gc_register_stack_start;
#endif

/* debug functions */

/* :nodoc: */
static VALUE
sdr(void)
{
    rb_vm_bugreport(NULL);
    return Qnil;
}

/* :nodoc: */
static VALUE
nsdr(void)
{
    VALUE ary = rb_ary_new();
#if HAVE_BACKTRACE
#include <execinfo.h>
#define MAX_NATIVE_TRACE 1024
    static void *trace[MAX_NATIVE_TRACE];
    int n = (int)backtrace(trace, MAX_NATIVE_TRACE);
    char **syms = backtrace_symbols(trace, n);
    int i;

    if (syms == 0) {
        rb_memerror();
    }

    for (i=0; i<n; i++) {
        rb_ary_push(ary, rb_str_new2(syms[i]));
    }
    free(syms); /* OK */
#endif
    return ary;
}

#if VM_COLLECT_USAGE_DETAILS
static VALUE usage_analysis_insn_stop(VALUE self);
static VALUE usage_analysis_operand_stop(VALUE self);
static VALUE usage_analysis_register_stop(VALUE self);
#endif

void
Init_VM(void)
{
    VALUE opts;
    VALUE klass;
    VALUE fcore;

    /* ::RubyVM */
    rb_cRubyVM = rb_define_class("RubyVM", rb_cObject);
    rb_undef_alloc_func(rb_cRubyVM);
    rb_undef_method(CLASS_OF(rb_cRubyVM), "new");
    rb_define_singleton_method(rb_cRubyVM, "stat", vm_stat, -1);

    /* FrozenCore (hidden) */
    fcore = rb_class_new(rb_cBasicObject);
    RBASIC(fcore)->flags = T_ICLASS;
    klass = rb_singleton_class(fcore);
    rb_define_method_id(klass, id_core_set_method_alias, m_core_set_method_alias, 3);
    rb_define_method_id(klass, id_core_set_variable_alias, m_core_set_variable_alias, 2);
    rb_define_method_id(klass, id_core_undef_method, m_core_undef_method, 2);
    rb_define_method_id(klass, id_core_define_method, m_core_define_method, 2);
    rb_define_method_id(klass, id_core_define_singleton_method, m_core_define_singleton_method, 3);
    rb_define_method_id(klass, id_core_set_postexe, m_core_set_postexe, 0);
    rb_define_method_id(klass, id_core_hash_from_ary, m_core_hash_from_ary, 1);
    rb_define_method_id(klass, id_core_hash_merge_ary, m_core_hash_merge_ary, 2);
    rb_define_method_id(klass, id_core_hash_merge_ptr, m_core_hash_merge_ptr, -1);
    rb_define_method_id(klass, id_core_hash_merge_kwd, m_core_hash_merge_kwd, -1);
    rb_define_method_id(klass, idProc, rb_block_proc, 0);
    rb_define_method_id(klass, idLambda, rb_block_lambda, 0);
    rb_obj_freeze(fcore);
    RBASIC_CLEAR_CLASS(klass);
    rb_obj_freeze(klass);
    rb_gc_register_mark_object(fcore);
    rb_mRubyVMFrozenCore = fcore;

    /* ::RubyVM::Env */
    rb_cEnv = rb_define_class_under(rb_cRubyVM, "Env", rb_cObject);
    rb_undef_alloc_func(rb_cEnv);
    rb_undef_method(CLASS_OF(rb_cEnv), "new");

    /*
     * Document-class: Thread
     *
     *  Threads are the Ruby implementation for a concurrent programming model.
     *
     *  Programs that require multiple threads of execution are a perfect
     *  candidate for Ruby's Thread class.
     *
     *  For example, we can create a new thread separate from the main thread's
     *  execution using ::new.
     *
     *      thr = Thread.new { puts "Whats the big deal" }
     *
     *  Then we are able to pause the execution of the main thread and allow
     *  our new thread to finish, using #join:
     *
     *      thr.join #=> "Whats the big deal"
     *
     *  If we don't call +thr.join+ before the main thread terminates, then all
     *  other threads including +thr+ will be killed.
     *
     *  Alternatively, you can use an array for handling multiple threads at
     *  once, like in the following example:
     *
     *      threads = []
     *      threads << Thread.new { puts "Whats the big deal" }
     *      threads << Thread.new { 3.times { puts "Threads are fun!" } }
     *
     *  After creating a few threads we wait for them all to finish
     *  consecutively.
     *
     *      threads.each { |thr| thr.join }
     *
     *  === Thread initialization
     *
     *  In order to create new threads, Ruby provides ::new, ::start, and
     *  ::fork. A block must be provided with each of these methods, otherwise
     *  a ThreadError will be raised.
     *
     *  When subclassing the Thread class, the +initialize+ method of your
     *  subclass will be ignored by ::start and ::fork. Otherwise, be sure to
     *  call super in your +initialize+ method.
     *
     *  === Thread termination
     *
     *  For terminating threads, Ruby provides a variety of ways to do this.
     *
     *  The class method ::kill, is meant to exit a given thread:
     *
     *      thr = Thread.new { ... }
     *      Thread.kill(thr) # sends exit() to thr
     *
     *  Alternatively, you can use the instance method #exit, or any of its
     *  aliases #kill or #terminate.
     *
     *      thr.exit
     *
     *  === Thread status
     *
     *  Ruby provides a few instance methods for querying the state of a given
     *  thread. To get a string with the current thread's state use #status
     *
     *      thr = Thread.new { sleep }
     *      thr.status # => "sleep"
     *      thr.exit
     *      thr.status # => false
     *
     *  You can also use #alive? to tell if the thread is running or sleeping,
     *  and #stop? if the thread is dead or sleeping.
     *
     *  === Thread variables and scope
     *
     *  Since threads are created with blocks, the same rules apply to other
     *  Ruby blocks for variable scope. Any local variables created within this
     *  block are accessible to only this thread.
     *
     *  ==== Fiber-local vs. Thread-local
     *
     *  Each fiber has its own bucket for Thread#[] storage. When you set a
     *  new fiber-local it is only accessible within this Fiber. To illustrate:
     *
     *      Thread.new {
     *        Thread.current[:foo] = "bar"
     *        Fiber.new {
     *          p Thread.current[:foo] # => nil
     *        }.resume
     *      }.join
     *
     *  This example uses #[] for getting and #[]= for setting fiber-locals,
     *  you can also use #keys to list the fiber-locals for a given
     *  thread and #key? to check if a fiber-local exists.
     *
     *  When it comes to thread-locals, they are accessible within the entire
     *  scope of the thread. Given the following example:
     *
     *      Thread.new{
     *        Thread.current.thread_variable_set(:foo, 1)
     *        p Thread.current.thread_variable_get(:foo) # => 1
     *        Fiber.new{
     *          Thread.current.thread_variable_set(:foo, 2)
     *          p Thread.current.thread_variable_get(:foo) # => 2
     *        }.resume
     *        p Thread.current.thread_variable_get(:foo)   # => 2
     *      }.join
     *
     *  You can see that the thread-local +:foo+ carried over into the fiber
     *  and was changed to +2+ by the end of the thread.
     *
     *  This example makes use of #thread_variable_set to create new
     *  thread-locals, and #thread_variable_get to reference them.
     *
     *  There is also #thread_variables to list all thread-locals, and
     *  #thread_variable? to check if a given thread-local exists.
     *
     *  === Exception handling
     *
     *  Any thread can raise an exception using the #raise instance method,
     *  which operates similarly to Kernel#raise.
     *
     *  However, it's important to note that an exception that occurs in any
     *  thread except the main thread depends on #abort_on_exception. This
     *  option is +false+ by default, meaning that any unhandled exception will
     *  cause the thread to terminate silently when waited on by either #join
     *  or #value. You can change this default by either #abort_on_exception=
     *  +true+ or setting $DEBUG to +true+.
     *
     *  With the addition of the class method ::handle_interrupt, you can now
     *  handle exceptions asynchronously with threads.
     *
     *  === Scheduling
     *
     *  Ruby provides a few ways to support scheduling threads in your program.
     *
     *  The first way is by using the class method ::stop, to put the current
     *  running thread to sleep and schedule the execution of another thread.
     *
     *  Once a thread is asleep, you can use the instance method #wakeup to
     *  mark your thread as eligible for scheduling.
     *
     *  You can also try ::pass, which attempts to pass execution to another
     *  thread but is dependent on the OS whether a running thread will switch
     *  or not. The same goes for #priority, which lets you hint to the thread
     *  scheduler which threads you want to take precedence when passing
     *  execution. This method is also dependent on the OS and may be ignored
     *  on some platforms.
     *
     */
    rb_cThread = rb_define_class("Thread", rb_cObject);
    rb_undef_alloc_func(rb_cThread);

#if VM_COLLECT_USAGE_DETAILS
    /* ::RubyVM::USAGE_ANALYSIS_* */
#define define_usage_analysis_hash(name) /* shut up rdoc -C */ \
    rb_define_const(rb_cRubyVM, "USAGE_ANALYSIS_" #name, rb_hash_new())
    define_usage_analysis_hash(INSN);
    define_usage_analysis_hash(REGS);
    define_usage_analysis_hash(INSN_BIGRAM);

    rb_define_singleton_method(rb_cRubyVM, "USAGE_ANALYSIS_INSN_STOP", usage_analysis_insn_stop, 0);
    rb_define_singleton_method(rb_cRubyVM, "USAGE_ANALYSIS_OPERAND_STOP", usage_analysis_operand_stop, 0);
    rb_define_singleton_method(rb_cRubyVM, "USAGE_ANALYSIS_REGISTER_STOP", usage_analysis_register_stop, 0);
#endif

    /* ::RubyVM::OPTS, which shows vm build options */
    rb_define_const(rb_cRubyVM, "OPTS", opts = rb_ary_new());

#if   OPT_DIRECT_THREADED_CODE
    rb_ary_push(opts, rb_str_new2("direct threaded code"));
#elif OPT_TOKEN_THREADED_CODE
    rb_ary_push(opts, rb_str_new2("token threaded code"));
#elif OPT_CALL_THREADED_CODE
    rb_ary_push(opts, rb_str_new2("call threaded code"));
#endif

#if OPT_STACK_CACHING
    rb_ary_push(opts, rb_str_new2("stack caching"));
#endif
#if OPT_OPERANDS_UNIFICATION
    rb_ary_push(opts, rb_str_new2("operands unification"));
#endif
#if OPT_INSTRUCTIONS_UNIFICATION
    rb_ary_push(opts, rb_str_new2("instructions unification"));
#endif
#if OPT_INLINE_METHOD_CACHE
    rb_ary_push(opts, rb_str_new2("inline method cache"));
#endif
#if OPT_BLOCKINLINING
    rb_ary_push(opts, rb_str_new2("block inlining"));
#endif

    /* ::RubyVM::INSTRUCTION_NAMES */
    rb_define_const(rb_cRubyVM, "INSTRUCTION_NAMES", rb_insns_name_array());

    /* ::RubyVM::DEFAULT_PARAMS
     * This constant variable shows VM's default parameters.
     * Note that changing these values does not affect VM execution.
     * Specification is not stable and you should not depend on this value.
     * Of course, this constant is MRI specific.
     */
    rb_define_const(rb_cRubyVM, "DEFAULT_PARAMS", vm_default_params());

    /* debug functions ::RubyVM::SDR(), ::RubyVM::NSDR() */
#if VMDEBUG
    rb_define_singleton_method(rb_cRubyVM, "SDR", sdr, 0);
    rb_define_singleton_method(rb_cRubyVM, "NSDR", nsdr, 0);
#else
    (void)sdr;
    (void)nsdr;
#endif

    /* VM bootstrap: phase 2 */
    {
        rb_vm_t *vm = ruby_current_vm;
        rb_thread_t *th = GET_THREAD();
        VALUE filename = rb_fstring_cstr("<main>");
        const rb_iseq_t *iseq = rb_iseq_new(0, filename, filename, Qnil, 0, ISEQ_TYPE_TOP);
        volatile VALUE th_self;

        /* create vm object */
        vm->self = TypedData_Wrap_Struct(rb_cRubyVM, &vm_data_type, vm);

        /* create main thread */
        th_self = th->self = TypedData_Wrap_Struct(rb_cThread, &thread_data_type, th);
        rb_iv_set(th_self, "locals", rb_hash_new());
        vm->main_thread = th;
        vm->running_thread = th;
        th->vm = vm;
        th->top_wrapper = 0;
        th->top_self = rb_vm_top_self();
        rb_thread_set_current(th);

        rb_vm_living_threads_insert(vm, th);

        rb_gc_register_mark_object((VALUE)iseq);
        th->cfp->iseq = iseq;
        th->cfp->pc = iseq->body->iseq_encoded;
        th->cfp->self = th->top_self;

        th->cfp->ep[-1] = (VALUE)vm_cref_new(rb_cObject, METHOD_VISI_PRIVATE, FALSE, NULL, FALSE);

        /*
         * The Binding of the top level scope
         */
        rb_define_global_const("TOPLEVEL_BINDING", rb_binding_new());
    }
    vm_init_redefined_flag();

    /* vm_backtrace.c */
    Init_vm_backtrace();
    VM_PROFILE_ATEXIT();
}

void
rb_vm_set_progname(VALUE filename)
{
    rb_thread_t *th = GET_VM()->main_thread;
    rb_control_frame_t *cfp = (void *)(th->stack + th->stack_size);
    --cfp;
    RB_OBJ_WRITE(cfp->iseq, &cfp->iseq->body->location.path, filename);
}

extern const struct st_hash_type rb_fstring_hash_type;

void
Init_BareVM(void)
{
    /* VM bootstrap: phase 1 */
    rb_vm_t * vm = ruby_mimmalloc(sizeof(*vm));
    rb_thread_t * th = ruby_mimmalloc(sizeof(*th));
    if (!vm || !th) {
        fprintf(stderr, "[FATAL] failed to allocate memory\n");
        exit(EXIT_FAILURE);
    }
    MEMZERO(th, rb_thread_t, 1);
    rb_thread_set_current_raw(th);

    vm_init2(vm);
    vm->objspace = rb_objspace_alloc();
    ruby_current_vm = vm;

    Init_native_thread();
    th->vm = vm;
    th_init(th, 0);
    ruby_thread_init_stack(th);
}

void
Init_vm_objects(void)
{
    rb_vm_t *vm = GET_VM();

    vm->defined_module_hash = rb_hash_new();

    /* initialize mark object array, hash */
    vm->mark_object_ary = rb_ary_tmp_new(128);
    vm->loading_table = st_init_strtable();
    vm->frozen_strings = st_init_table_with_size(&rb_fstring_hash_type, 1000);
}

/* top self */

static VALUE
main_to_s(VALUE obj)
{
    return rb_str_new2("main");
}

VALUE
rb_vm_top_self(void)
{
    return GET_VM()->top_self;
}

void
Init_top_self(void)
{
    rb_vm_t *vm = GET_VM();

    vm->top_self = rb_obj_alloc(rb_cObject);
    rb_define_singleton_method(rb_vm_top_self(), "to_s", main_to_s, 0);
    rb_define_alias(rb_singleton_class(rb_vm_top_self()), "inspect", "to_s");
}

static VALUE *
ruby_vm_verbose_ptr(rb_vm_t *vm)
{
    return &vm->verbose;
}

static VALUE *
ruby_vm_debug_ptr(rb_vm_t *vm)
{
    return &vm->debug;
}

VALUE *
rb_ruby_verbose_ptr(void)
{
    return ruby_vm_verbose_ptr(GET_VM());
}

VALUE *
rb_ruby_debug_ptr(void)
{
    return ruby_vm_debug_ptr(GET_VM());
}

/* iseq.c */
VALUE rb_insn_operand_intern(const rb_iseq_t *iseq,
                             VALUE insn, int op_no, VALUE op,
                             int len, size_t pos, VALUE *pnop, VALUE child);

st_table *
rb_vm_fstring_table(void)
{
    return GET_VM()->frozen_strings;
}

#if VM_COLLECT_USAGE_DETAILS

#define HASH_ASET(h, k, v) rb_hash_aset((h), (st_data_t)(k), (st_data_t)(v))

/* uh = {
 *   insn(Fixnum) => ihash(Hash)
 * }
 * ihash = {
 *   -1(Fixnum) => count,      # insn usage
 *    0(Fixnum) => ophash,     # operand usage
 * }
 * ophash = {
 *   val(interned string) => count(Fixnum)
 * }
 */
static void
vm_analysis_insn(int insn)
{
    ID usage_hash;
    ID bigram_hash;
    static int prev_insn = -1;

    VALUE uh;
    VALUE ihash;
    VALUE cv;

    CONST_ID(usage_hash, "USAGE_ANALYSIS_INSN");
    CONST_ID(bigram_hash, "USAGE_ANALYSIS_INSN_BIGRAM");
    uh = rb_const_get(rb_cRubyVM, usage_hash);
    if ((ihash = rb_hash_aref(uh, INT2FIX(insn))) == Qnil) {
        ihash = rb_hash_new();
        HASH_ASET(uh, INT2FIX(insn), ihash);
    }
    if ((cv = rb_hash_aref(ihash, INT2FIX(-1))) == Qnil) {
        cv = INT2FIX(0);
    }
    HASH_ASET(ihash, INT2FIX(-1), INT2FIX(FIX2INT(cv) + 1));

    /* calc bigram */
    if (prev_insn != -1) {
        VALUE bi;
        VALUE ary[2];
        VALUE cv;

        ary[0] = INT2FIX(prev_insn);
        ary[1] = INT2FIX(insn);
        bi = rb_ary_new4(2, &ary[0]);

        uh = rb_const_get(rb_cRubyVM, bigram_hash);
        if ((cv = rb_hash_aref(uh, bi)) == Qnil) {
            cv = INT2FIX(0);
        }
        HASH_ASET(uh, bi, INT2FIX(FIX2INT(cv) + 1));
    }
    prev_insn = insn;
}

static void
vm_analysis_operand(int insn, int n, VALUE op)
{
    ID usage_hash;

    VALUE uh;
    VALUE ihash;
    VALUE ophash;
    VALUE valstr;
    VALUE cv;

    CONST_ID(usage_hash, "USAGE_ANALYSIS_INSN");

    uh = rb_const_get(rb_cRubyVM, usage_hash);
    if ((ihash = rb_hash_aref(uh, INT2FIX(insn))) == Qnil) {
        ihash = rb_hash_new();
        HASH_ASET(uh, INT2FIX(insn), ihash);
    }
    if ((ophash = rb_hash_aref(ihash, INT2FIX(n))) == Qnil) {
        ophash = rb_hash_new();
        HASH_ASET(ihash, INT2FIX(n), ophash);
    }
    /* intern */
    valstr = rb_insn_operand_intern(GET_THREAD()->cfp->iseq, insn, n, op, 0, 0, 0, 0);

    /* set count */
    if ((cv = rb_hash_aref(ophash, valstr)) == Qnil) {
        cv = INT2FIX(0);
    }
    HASH_ASET(ophash, valstr, INT2FIX(FIX2INT(cv) + 1));
}

static void
vm_analysis_register(int reg, int isset)
{
    ID usage_hash;
    VALUE uh;
    VALUE valstr;
    static const char regstrs[][5] = {
        "pc",                   /* 0 */
        "sp",                   /* 1 */
        "ep",                   /* 2 */
        "cfp",                  /* 3 */
        "self",                 /* 4 */
        "iseq",                 /* 5 */
    };
    static const char getsetstr[][4] = {
        "get",
        "set",
    };
    static VALUE syms[sizeof(regstrs) / sizeof(regstrs[0])][2];

    VALUE cv;

    CONST_ID(usage_hash, "USAGE_ANALYSIS_REGS");
    if (syms[0] == 0) {
        char buff[0x10];
        int i;

        for (i = 0; i < (int)(sizeof(regstrs) / sizeof(regstrs[0])); i++) {
            int j;
            for (j = 0; j < 2; j++) {
                snprintf(buff, 0x10, "%d %s %-4s", i, getsetstr[j], regstrs[i]);
                syms[i][j] = ID2SYM(rb_intern(buff));
            }
        }
    }
    valstr = syms[reg][isset];

    uh = rb_const_get(rb_cRubyVM, usage_hash);
    if ((cv = rb_hash_aref(uh, valstr)) == Qnil) {
        cv = INT2FIX(0);
    }
    HASH_ASET(uh, valstr, INT2FIX(FIX2INT(cv) + 1));
}

#undef HASH_ASET

void (*ruby_vm_collect_usage_func_insn)(int insn) = vm_analysis_insn;
void (*ruby_vm_collect_usage_func_operand)(int insn, int n, VALUE op) = vm_analysis_operand;
void (*ruby_vm_collect_usage_func_register)(int reg, int isset) = vm_analysis_register;

/* :nodoc: */
static VALUE
usage_analysis_insn_stop(VALUE self)
{
    ruby_vm_collect_usage_func_insn = 0;
    return Qnil;
}

/* :nodoc: */
static VALUE
usage_analysis_operand_stop(VALUE self)
{
    ruby_vm_collect_usage_func_operand = 0;
    return Qnil;
}

/* :nodoc: */
static VALUE
usage_analysis_register_stop(VALUE self)
{
    ruby_vm_collect_usage_func_register = 0;
    return Qnil;
}

#else

void (*ruby_vm_collect_usage_func_insn)(int insn) = NULL;
void (*ruby_vm_collect_usage_func_operand)(int insn, int n, VALUE op) = NULL;
void (*ruby_vm_collect_usage_func_register)(int reg, int isset) = NULL;

#endif

#if VM_COLLECT_USAGE_DETAILS
/* @param insn instruction number */
static void
vm_collect_usage_insn(int insn)
{
    if (RUBY_DTRACE_INSN_ENABLED()) {
        RUBY_DTRACE_INSN(rb_insns_name(insn));
    }
    if (ruby_vm_collect_usage_func_insn)
        (*ruby_vm_collect_usage_func_insn)(insn);
}

/* @param insn instruction number
 * @param n    n-th operand
 * @param op   operand value
 */
static void
vm_collect_usage_operand(int insn, int n, VALUE op)
{
    if (RUBY_DTRACE_INSN_OPERAND_ENABLED()) {
        VALUE valstr;

        valstr = rb_insn_operand_intern(GET_THREAD()->cfp->iseq, insn, n, op, 0, 0, 0, 0);

        RUBY_DTRACE_INSN_OPERAND(RSTRING_PTR(valstr), rb_insns_name(insn));
        RB_GC_GUARD(valstr);
    }
    if (ruby_vm_collect_usage_func_operand)
        (*ruby_vm_collect_usage_func_operand)(insn, n, op);
}

/* @param reg register id. see code of vm_analysis_register() */
/* @param isset 0: read, 1: write */
static void
vm_collect_usage_register(int reg, int isset)
{
    if (ruby_vm_collect_usage_func_register)
        (*ruby_vm_collect_usage_func_register)(reg, isset);
}
#endif

#include "vm_call_iseq_optimized.inc" /* required from vm_insnhelper.c */

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