* eval_method.c: renamed from vm_method.c. "vm_method.c" is included

  by "vm.c".
* vm_eval.c: added.  Some codes are moved from "eval.c"
* common.mk: fix for above changes.
* compile.c: make a vm_eval(0)
* eval.c, eval_error.c, eval_intern.h, eval_jump.c, proc.c, vm.c,
  id.c, id.h, vm_core.h, vm_dump.c, vm_evalbody.c, vm_insnhelper.c,
  blockinlining.c: fix for above changes.  and do some refactoring.
  this changes improve rb_yield() performance.



git-svn-id: http://svn.ruby-lang.org/repos/ruby/trunk@16576 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1145 insertions, 0 deletions

diff --git a/vm_method.c b/vm_method.c
new file mode 100644
index 000000000..8c3f7f0a6
--- /dev/null
+++ b/vm_method.c
@@ -0,0 +1,1145 @@
+/* -*-c-*- */
+/*
+ * This file is included by vm_eval.c
+ */
+
+#define CACHE_SIZE 0x800
+#define CACHE_MASK 0x7ff
+#define EXPR1(c,m) ((((c)>>3)^(m))&CACHE_MASK)
+
+static void rb_vm_check_redefinition_opt_method(const NODE *node);
+
+static ID __send__, object_id;
+static ID removed, singleton_removed, undefined, singleton_undefined;
+static ID eqq, each, aref, aset, match, missing;
+static ID added, singleton_added;
+
+struct cache_entry {		/* method hash table. */
+    ID mid;			/* method's id */
+    ID mid0;			/* method's original id */
+    VALUE klass;		/* receiver's class */
+    VALUE oklass;		/* original's class */
+    NODE *method;
+};
+
+static struct cache_entry cache[CACHE_SIZE];
+#define ruby_running (GET_VM()->running)
+/* int ruby_running = 0; */
+
+void
+rb_clear_cache(void)
+{
+    struct cache_entry *ent, *end;
+
+    rb_vm_change_state();
+
+    if (!ruby_running)
+	return;
+    ent = cache;
+    end = ent + CACHE_SIZE;
+    while (ent < end) {
+	ent->mid = 0;
+	ent++;
+    }
+}
+
+static void
+rb_clear_cache_for_undef(VALUE klass, ID id)
+{
+    struct cache_entry *ent, *end;
+
+    rb_vm_change_state();
+
+    if (!ruby_running)
+	return;
+    ent = cache;
+    end = ent + CACHE_SIZE;
+    while (ent < end) {
+	if (ent->oklass == klass && ent->mid == id) {
+	    ent->mid = 0;
+	}
+	ent++;
+    }
+}
+
+static void
+rb_clear_cache_by_id(ID id)
+{
+    struct cache_entry *ent, *end;
+
+    rb_vm_change_state();
+
+    if (!ruby_running)
+	return;
+    ent = cache;
+    end = ent + CACHE_SIZE;
+    while (ent < end) {
+	if (ent->mid == id) {
+	    ent->mid = 0;
+	}
+	ent++;
+    }
+}
+
+void
+rb_clear_cache_by_class(VALUE klass)
+{
+    struct cache_entry *ent, *end;
+
+    rb_vm_change_state();
+
+    if (!ruby_running)
+	return;
+    ent = cache;
+    end = ent + CACHE_SIZE;
+    while (ent < end) {
+	if (ent->klass == klass || ent->oklass == klass) {
+	    ent->mid = 0;
+	}
+	ent++;
+    }
+}
+
+void
+rb_add_method(VALUE klass, ID mid, NODE * node, int noex)
+{
+    NODE *body;
+
+    if (NIL_P(klass)) {
+	klass = rb_cObject;
+    }
+    if (rb_safe_level() >= 4 && (klass == rb_cObject || !OBJ_TAINTED(klass))) {
+	rb_raise(rb_eSecurityError, "Insecure: can't define method");
+    }
+    if (!FL_TEST(klass, FL_SINGLETON) &&
+	node && nd_type(node) != NODE_ZSUPER &&
+	(mid == rb_intern("initialize") || mid == rb_intern("initialize_copy"))) {
+	noex = NOEX_PRIVATE | noex;
+    }
+    else if (FL_TEST(klass, FL_SINGLETON) && node
+	     && nd_type(node) == NODE_CFUNC && mid == rb_intern("allocate")) {
+	rb_warn
+	    ("defining %s.allocate is deprecated; use rb_define_alloc_func()",
+	     rb_class2name(rb_iv_get(klass, "__attached__")));
+	mid = ID_ALLOCATOR;
+    }
+    if (OBJ_FROZEN(klass)) {
+	rb_error_frozen("class/module");
+    }
+    rb_clear_cache_by_id(mid);
+
+    /*
+     * NODE_METHOD (NEW_METHOD(body, klass, vis)):
+     *   nd_body : method body   // (2) // mark
+     *   nd_clss : klass         // (1) // mark
+     *   nd_noex : visibility    // (3)
+     *
+     * NODE_FBODY (NEW_FBODY(method, alias)):
+     *   nd_body : method (NODE_METHOD)  // (2) // mark
+     *   nd_oid  : original id           // (1)
+     *   nd_cnt  : alias count           // (3)
+     */
+    if (node) {
+	body = NEW_FBODY(NEW_METHOD(node, klass, NOEX_WITH_SAFE(noex)), 0);
+    }
+    else {
+	body = 0;
+    }
+
+    {
+	/* check re-definition */
+	st_data_t data;
+	NODE *old_node;
+
+	if (st_lookup(RCLASS_M_TBL(klass), mid, &data)) {
+	    old_node = (NODE *)data;
+	    if (old_node) {
+		if (nd_type(old_node->nd_body->nd_body) == NODE_CFUNC) {
+		    rb_vm_check_redefinition_opt_method(old_node);
+		}
+		if (RTEST(ruby_verbose) && node && old_node->nd_cnt == 0 && old_node->nd_body) {
+		    rb_warning("method redefined; discarding old %s", rb_id2name(mid));
+		}
+	    }
+	}
+	if (klass == rb_cObject && node && mid == idInitialize) {
+	    rb_warn("redefining Object#initialize may cause infinite loop");
+	}
+
+	if (mid == object_id || mid == __send__) {
+	    if (node && nd_type(node) == RUBY_VM_METHOD_NODE) {
+		rb_warn("redefining `%s' may cause serious problem",
+			rb_id2name(mid));
+	    }
+	}
+    }
+
+    st_insert(RCLASS_M_TBL(klass), mid, (st_data_t) body);
+
+    if (node && mid != ID_ALLOCATOR && ruby_running) {
+	if (FL_TEST(klass, FL_SINGLETON)) {
+	    rb_funcall(rb_iv_get(klass, "__attached__"), singleton_added, 1,
+		       ID2SYM(mid));
+	}
+	else {
+	    rb_funcall(klass, added, 1, ID2SYM(mid));
+	}
+    }
+}
+
+void
+rb_define_alloc_func(VALUE klass, VALUE (*func)(VALUE))
+{
+    Check_Type(klass, T_CLASS);
+    rb_add_method(rb_singleton_class(klass), ID_ALLOCATOR, NEW_CFUNC(func, 0),
+		  NOEX_PRIVATE);
+}
+
+void
+rb_undef_alloc_func(VALUE klass)
+{
+    Check_Type(klass, T_CLASS);
+    rb_add_method(rb_singleton_class(klass), ID_ALLOCATOR, 0, NOEX_UNDEF);
+}
+
+rb_alloc_func_t
+rb_get_alloc_func(VALUE klass)
+{
+    NODE *n;
+    Check_Type(klass, T_CLASS);
+    n = rb_method_node(CLASS_OF(klass), ID_ALLOCATOR);
+    if (!n) return 0;
+    if (nd_type(n) != NODE_METHOD) return 0;
+    n = n->nd_body;
+    if (nd_type(n) != NODE_CFUNC) return 0;
+    return (rb_alloc_func_t)n->nd_cfnc;
+}
+
+static NODE *
+search_method(VALUE klass, ID id, VALUE *klassp)
+{
+    st_data_t body;
+
+    if (!klass) {
+	return 0;
+    }
+
+    while (!st_lookup(RCLASS_M_TBL(klass), id, &body)) {
+	klass = RCLASS_SUPER(klass);
+	if (!klass)
+	    return 0;
+    }
+
+    if (klassp) {
+	*klassp = klass;
+    }
+
+    return (NODE *)body;
+}
+
+/*
+ * search method body (NODE_METHOD)
+ *   with    : klass and id
+ *   without : method cache
+ *
+ * if you need method node with method cache, use
+ * rb_method_node()
+ */
+NODE *
+rb_get_method_body(VALUE klass, ID id, ID *idp)
+{
+    NODE *volatile fbody, *body;
+    NODE *method;
+
+    if ((fbody = search_method(klass, id, 0)) == 0 || !fbody->nd_body) {
+	/* store empty info in cache */
+	struct cache_entry *ent;
+	ent = cache + EXPR1(klass, id);
+	ent->klass = klass;
+	ent->mid = ent->mid0 = id;
+	ent->method = 0;
+	ent->oklass = 0;
+	return 0;
+    }
+
+    method = fbody->nd_body;
+
+    if (ruby_running) {
+	/* store in cache */
+	struct cache_entry *ent;
+	ent = cache + EXPR1(klass, id);
+	ent->klass = klass;
+	ent->mid = id;
+	ent->mid0 = fbody->nd_oid;
+	ent->method = body = method;
+	ent->oklass = method->nd_clss;
+    }
+    else {
+	body = method;
+    }
+
+    if (idp) {
+	*idp = fbody->nd_oid;
+    }
+
+    return body;
+}
+
+NODE *
+rb_method_node(VALUE klass, ID id)
+{
+    struct cache_entry *ent;
+
+    ent = cache + EXPR1(klass, id);
+    if (ent->mid == id && ent->klass == klass && ent->method) {
+	return ent->method;
+    }
+
+    return rb_get_method_body(klass, id, 0);
+}
+
+static void
+remove_method(VALUE klass, ID mid)
+{
+    st_data_t data;
+    NODE *body = 0;
+
+    if (klass == rb_cObject) {
+	rb_secure(4);
+    }
+    if (rb_safe_level() >= 4 && !OBJ_TAINTED(klass)) {
+	rb_raise(rb_eSecurityError, "Insecure: can't remove method");
+    }
+    if (OBJ_FROZEN(klass))
+	rb_error_frozen("class/module");
+    if (mid == object_id || mid == __send__ || mid == idInitialize) {
+	rb_warn("removing `%s' may cause serious problem", rb_id2name(mid));
+    }
+    if (st_lookup(RCLASS_M_TBL(klass), mid, &data)) {
+	body = (NODE *)data;
+	if (!body || !body->nd_body) body = 0;
+	else {
+	    st_delete(RCLASS_M_TBL(klass), &mid, &data);
+	}
+    }
+    if (!body) {
+	rb_name_error(mid, "method `%s' not defined in %s",
+		      rb_id2name(mid), rb_class2name(klass));
+    }
+
+    if (nd_type(body->nd_body->nd_body) == NODE_CFUNC) {
+	rb_vm_check_redefinition_opt_method(body);
+    }
+
+    rb_clear_cache_for_undef(klass, mid);
+    if (FL_TEST(klass, FL_SINGLETON)) {
+	rb_funcall(rb_iv_get(klass, "__attached__"), singleton_removed, 1,
+		   ID2SYM(mid));
+    }
+    else {
+	rb_funcall(klass, removed, 1, ID2SYM(mid));
+    }
+}
+
+void
+rb_remove_method(VALUE klass, const char *name)
+{
+    remove_method(klass, rb_intern(name));
+}
+
+/*
+ *  call-seq:
+ *     remove_method(symbol)   => self
+ *
+ *  Removes the method identified by _symbol_ from the current
+ *  class. For an example, see <code>Module.undef_method</code>.
+ */
+
+static VALUE
+rb_mod_remove_method(int argc, VALUE *argv, VALUE mod)
+{
+    int i;
+
+    for (i = 0; i < argc; i++) {
+	remove_method(mod, rb_to_id(argv[i]));
+    }
+    return mod;
+}
+
+#undef rb_disable_super
+#undef rb_enable_super
+
+void
+rb_disable_super(VALUE klass, const char *name)
+{
+    /* obsolete - no use */
+}
+
+void
+rb_enable_super(VALUE klass, const char *name)
+{
+    rb_warning("rb_enable_super() is obsolete");
+}
+
+static void
+rb_export_method(VALUE klass, ID name, ID noex)
+{
+    NODE *fbody;
+    VALUE origin;
+
+    if (klass == rb_cObject) {
+	rb_secure(4);
+    }
+    fbody = search_method(klass, name, &origin);
+    if (!fbody && TYPE(klass) == T_MODULE) {
+	fbody = search_method(rb_cObject, name, &origin);
+    }
+    if (!fbody || !fbody->nd_body) {
+	rb_print_undef(klass, name, 0);
+    }
+    if (fbody->nd_body->nd_noex != noex) {
+	if (nd_type(fbody->nd_body->nd_body) == NODE_CFUNC) {
+	    rb_vm_check_redefinition_opt_method(fbody);
+	}
+	if (klass == origin) {
+	    fbody->nd_body->nd_noex = noex;
+	}
+	else {
+	    rb_add_method(klass, name, NEW_ZSUPER(), noex);
+	}
+    }
+}
+
+int
+rb_method_boundp(VALUE klass, ID id, int ex)
+{
+    NODE *method;
+
+    if ((method = rb_method_node(klass, id)) != 0) {
+	if (ex && (method->nd_noex & NOEX_PRIVATE)) {
+	    return Qfalse;
+	}
+	return Qtrue;
+    }
+    return Qfalse;
+}
+
+void
+rb_attr(VALUE klass, ID id, int read, int write, int ex)
+{
+    const char *name;
+    ID attriv;
+    int noex;
+
+    if (!ex) {
+	noex = NOEX_PUBLIC;
+    }
+    else {
+	if (SCOPE_TEST(NOEX_PRIVATE)) {
+	    noex = NOEX_PRIVATE;
+	    rb_warning((SCOPE_CHECK(NOEX_MODFUNC)) ?
+		       "attribute accessor as module_function" :
+		       "private attribute?");
+	}
+	else if (SCOPE_TEST(NOEX_PROTECTED)) {
+	    noex = NOEX_PROTECTED;
+	}
+	else {
+	    noex = NOEX_PUBLIC;
+	}
+    }
+
+    if (!rb_is_local_id(id) && !rb_is_const_id(id)) {
+	rb_name_error(id, "invalid attribute name `%s'", rb_id2name(id));
+    }
+    name = rb_id2name(id);
+    if (!name) {
+	rb_raise(rb_eArgError, "argument needs to be symbol or string");
+    }
+    attriv = rb_intern_str(rb_sprintf("@%s", name));
+    if (read) {
+	rb_add_method(klass, id, NEW_IVAR(attriv), noex);
+    }
+    if (write) {
+	rb_add_method(klass, rb_id_attrset(id), NEW_ATTRSET(attriv), noex);
+    }
+}
+
+void
+rb_undef(VALUE klass, ID id)
+{
+    VALUE origin;
+    NODE *body;
+
+    if (rb_vm_cbase() == rb_cObject && klass == rb_cObject) {
+	rb_secure(4);
+    }
+    if (rb_safe_level() >= 4 && !OBJ_TAINTED(klass)) {
+	rb_raise(rb_eSecurityError, "Insecure: can't undef `%s'",
+		 rb_id2name(id));
+    }
+    rb_frozen_class_p(klass);
+    if (id == object_id || id == __send__ || id == idInitialize) {
+	rb_warn("undefining `%s' may cause serious problem", rb_id2name(id));
+    }
+    body = search_method(klass, id, &origin);
+    if (!body || !body->nd_body) {
+	char *s0 = " class";
+	VALUE c = klass;
+
+	if (FL_TEST(c, FL_SINGLETON)) {
+	    VALUE obj = rb_iv_get(klass, "__attached__");
+
+	    switch (TYPE(obj)) {
+	      case T_MODULE:
+	      case T_CLASS:
+		c = obj;
+		s0 = "";
+	    }
+	}
+	else if (TYPE(c) == T_MODULE) {
+	    s0 = " module";
+	}
+	rb_name_error(id, "undefined method `%s' for%s `%s'",
+		      rb_id2name(id), s0, rb_class2name(c));
+    }
+
+    rb_add_method(klass, id, 0, NOEX_PUBLIC);
+
+    if (FL_TEST(klass, FL_SINGLETON)) {
+	rb_funcall(rb_iv_get(klass, "__attached__"),
+		   singleton_undefined, 1, ID2SYM(id));
+    }
+    else {
+	rb_funcall(klass, undefined, 1, ID2SYM(id));
+    }
+}
+
+/*
+ *  call-seq:
+ *     undef_method(symbol)    => self
+ *
+ *  Prevents the current class from responding to calls to the named
+ *  method. Contrast this with <code>remove_method</code>, which deletes
+ *  the method from the particular class; Ruby will still search
+ *  superclasses and mixed-in modules for a possible receiver.
+ *
+ *     class Parent
+ *       def hello
+ *         puts "In parent"
+ *       end
+ *     end
+ *     class Child < Parent
+ *       def hello
+ *         puts "In child"
+ *       end
+ *     end
+ *
+ *
+ *     c = Child.new
+ *     c.hello
+ *
+ *
+ *     class Child
+ *       remove_method :hello  # remove from child, still in parent
+ *     end
+ *     c.hello
+ *
+ *
+ *     class Child
+ *       undef_method :hello   # prevent any calls to 'hello'
+ *     end
+ *     c.hello
+ *
+ *  <em>produces:</em>
+ *
+ *     In child
+ *     In parent
+ *     prog.rb:23: undefined method `hello' for #<Child:0x401b3bb4> (NoMethodError)
+ */
+
+static VALUE
+rb_mod_undef_method(int argc, VALUE *argv, VALUE mod)
+{
+    int i;
+    for (i = 0; i < argc; i++) {
+	rb_undef(mod, rb_to_id(argv[i]));
+    }
+    return mod;
+}
+
+/*
+ *  call-seq:
+ *     mod.method_defined?(symbol)    => true or false
+ *
+ *  Returns +true+ if the named method is defined by
+ *  _mod_ (or its included modules and, if _mod_ is a class,
+ *  its ancestors). Public and protected methods are matched.
+ *
+ *     module A
+ *       def method1()  end
+ *     end
+ *     class B
+ *       def method2()  end
+ *     end
+ *     class C < B
+ *       include A
+ *       def method3()  end
+ *     end
+ *
+ *     A.method_defined? :method1    #=> true
+ *     C.method_defined? "method1"   #=> true
+ *     C.method_defined? "method2"   #=> true
+ *     C.method_defined? "method3"   #=> true
+ *     C.method_defined? "method4"   #=> false
+ */
+
+static VALUE
+rb_mod_method_defined(VALUE mod, VALUE mid)
+{
+    return rb_method_boundp(mod, rb_to_id(mid), 1);
+}
+
+#define VISI_CHECK(x,f) (((x)&NOEX_MASK) == (f))
+
+/*
+ *  call-seq:
+ *     mod.public_method_defined?(symbol)   => true or false
+ *
+ *  Returns +true+ if the named public method is defined by
+ *  _mod_ (or its included modules and, if _mod_ is a class,
+ *  its ancestors).
+ *
+ *     module A
+ *       def method1()  end
+ *     end
+ *     class B
+ *       protected
+ *       def method2()  end
+ *     end
+ *     class C < B
+ *       include A
+ *       def method3()  end
+ *     end
+ *
+ *     A.method_defined? :method1           #=> true
+ *     C.public_method_defined? "method1"   #=> true
+ *     C.public_method_defined? "method2"   #=> false
+ *     C.method_defined? "method2"          #=> true
+ */
+
+static VALUE
+rb_mod_public_method_defined(VALUE mod, VALUE mid)
+{
+    ID id = rb_to_id(mid);
+    NODE *method;
+
+    method = rb_method_node(mod, id);
+    if (method) {
+	if (VISI_CHECK(method->nd_noex, NOEX_PUBLIC))
+	    return Qtrue;
+    }
+    return Qfalse;
+}
+
+/*
+ *  call-seq:
+ *     mod.private_method_defined?(symbol)    => true or false
+ *
+ *  Returns +true+ if the named private method is defined by
+ *  _ mod_ (or its included modules and, if _mod_ is a class,
+ *  its ancestors).
+ *
+ *     module A
+ *       def method1()  end
+ *     end
+ *     class B
+ *       private
+ *       def method2()  end
+ *     end
+ *     class C < B
+ *       include A
+ *       def method3()  end
+ *     end
+ *
+ *     A.method_defined? :method1            #=> true
+ *     C.private_method_defined? "method1"   #=> false
+ *     C.private_method_defined? "method2"   #=> true
+ *     C.method_defined? "method2"           #=> false
+ */
+
+static VALUE
+rb_mod_private_method_defined(VALUE mod, VALUE mid)
+{
+    ID id = rb_to_id(mid);
+    NODE *method;
+
+    method = rb_method_node(mod, id);
+    if (method) {
+	if (VISI_CHECK(method->nd_noex, NOEX_PRIVATE))
+	    return Qtrue;
+    }
+    return Qfalse;
+}
+
+/*
+ *  call-seq:
+ *     mod.protected_method_defined?(symbol)   => true or false
+ *
+ *  Returns +true+ if the named protected method is defined
+ *  by _mod_ (or its included modules and, if _mod_ is a
+ *  class, its ancestors).
+ *
+ *     module A
+ *       def method1()  end
+ *     end
+ *     class B
+ *       protected
+ *       def method2()  end
+ *     end
+ *     class C < B
+ *       include A
+ *       def method3()  end
+ *     end
+ *
+ *     A.method_defined? :method1              #=> true
+ *     C.protected_method_defined? "method1"   #=> false
+ *     C.protected_method_defined? "method2"   #=> true
+ *     C.method_defined? "method2"             #=> true
+ */
+
+static VALUE
+rb_mod_protected_method_defined(VALUE mod, VALUE mid)
+{
+    ID id = rb_to_id(mid);
+    NODE *method;
+
+    method = rb_method_node(mod, id);
+    if (method) {
+	if (VISI_CHECK(method->nd_noex, NOEX_PROTECTED))
+	    return Qtrue;
+    }
+    return Qfalse;
+}
+
+void
+rb_alias(VALUE klass, ID name, ID def)
+{
+    NODE *orig_fbody, *node;
+    VALUE singleton = 0;
+    st_data_t data;
+
+    rb_frozen_class_p(klass);
+    if (klass == rb_cObject) {
+	rb_secure(4);
+    }
+    orig_fbody = search_method(klass, def, 0);
+    if (!orig_fbody || !orig_fbody->nd_body) {
+	if (TYPE(klass) == T_MODULE) {
+	    orig_fbody = search_method(rb_cObject, def, 0);
+	}
+    }
+    if (!orig_fbody || !orig_fbody->nd_body) {
+	rb_print_undef(klass, def, 0);
+    }
+    if (FL_TEST(klass, FL_SINGLETON)) {
+	singleton = rb_iv_get(klass, "__attached__");
+    }
+
+    orig_fbody->nd_cnt++;
+
+    if (st_lookup(RCLASS_M_TBL(klass), name, &data)) {
+	node = (NODE *)data;
+	if (node) {
+	    if (RTEST(ruby_verbose) && node->nd_cnt == 0 && node->nd_body) {
+		rb_warning("discarding old %s", rb_id2name(name));
+	    }
+	    if (nd_type(node->nd_body->nd_body) == NODE_CFUNC) {
+		rb_vm_check_redefinition_opt_method(node);
+	    }
+	}
+    }
+
+    st_insert(RCLASS_M_TBL(klass), name,
+	      (st_data_t) NEW_FBODY(
+		  NEW_METHOD(orig_fbody->nd_body->nd_body,
+			     orig_fbody->nd_body->nd_clss,
+			     NOEX_WITH_SAFE(orig_fbody->nd_body->nd_noex)), def));
+
+    rb_clear_cache_by_id(name);
+
+    if (!ruby_running) return;
+
+    if (singleton) {
+	rb_funcall(singleton, singleton_added, 1, ID2SYM(name));
+    }
+    else {
+	rb_funcall(klass, added, 1, ID2SYM(name));
+    }
+}
+
+/*
+ *  call-seq:
+ *     alias_method(new_name, old_name)   => self
+ *
+ *  Makes <i>new_name</i> a new copy of the method <i>old_name</i>. This can
+ *  be used to retain access to methods that are overridden.
+ *
+ *     module Mod
+ *       alias_method :orig_exit, :exit
+ *       def exit(code=0)
+ *         puts "Exiting with code #{code}"
+ *         orig_exit(code)
+ *       end
+ *     end
+ *     include Mod
+ *     exit(99)
+ *
+ *  <em>produces:</em>
+ *
+ *     Exiting with code 99
+ */
+
+static VALUE
+rb_mod_alias_method(VALUE mod, VALUE newname, VALUE oldname)
+{
+    rb_alias(mod, rb_to_id(newname), rb_to_id(oldname));
+    return mod;
+}
+
+static void
+secure_visibility(VALUE self)
+{
+    if (rb_safe_level() >= 4 && !OBJ_TAINTED(self)) {
+	rb_raise(rb_eSecurityError,
+		 "Insecure: can't change method visibility");
+    }
+}
+
+static void
+set_method_visibility(VALUE self, int argc, VALUE *argv, ID ex)
+{
+    int i;
+    secure_visibility(self);
+    for (i = 0; i < argc; i++) {
+	rb_export_method(self, rb_to_id(argv[i]), ex);
+    }
+    rb_clear_cache_by_class(self);
+}
+
+/*
+ *  call-seq:
+ *     public                 => self
+ *     public(symbol, ...)    => self
+ *
+ *  With no arguments, sets the default visibility for subsequently
+ *  defined methods to public. With arguments, sets the named methods to
+ *  have public visibility.
+ */
+
+static VALUE
+rb_mod_public(int argc, VALUE *argv, VALUE module)
+{
+    secure_visibility(module);
+    if (argc == 0) {
+	SCOPE_SET(NOEX_PUBLIC);
+    }
+    else {
+	set_method_visibility(module, argc, argv, NOEX_PUBLIC);
+    }
+    return module;
+}
+
+/*
+ *  call-seq:
+ *     protected                => self
+ *     protected(symbol, ...)   => self
+ *
+ *  With no arguments, sets the default visibility for subsequently
+ *  defined methods to protected. With arguments, sets the named methods
+ *  to have protected visibility.
+ */
+
+static VALUE
+rb_mod_protected(int argc, VALUE *argv, VALUE module)
+{
+    secure_visibility(module);
+    if (argc == 0) {
+	SCOPE_SET(NOEX_PROTECTED);
+    }
+    else {
+	set_method_visibility(module, argc, argv, NOEX_PROTECTED);
+    }
+    return module;
+}
+
+/*
+ *  call-seq:
+ *     private                 => self
+ *     private(symbol, ...)    => self
+ *
+ *  With no arguments, sets the default visibility for subsequently
+ *  defined methods to private. With arguments, sets the named methods
+ *  to have private visibility.
+ *
+ *     module Mod
+ *       def a()  end
+ *       def b()  end
+ *       private
+ *       def c()  end
+ *       private :a
+ *     end
+ *     Mod.private_instance_methods   #=> [:a, :c]
+ */
+
+static VALUE
+rb_mod_private(int argc, VALUE *argv, VALUE module)
+{
+    secure_visibility(module);
+    if (argc == 0) {
+	SCOPE_SET(NOEX_PRIVATE);
+    }
+    else {
+	set_method_visibility(module, argc, argv, NOEX_PRIVATE);
+    }
+    return module;
+}
+
+/*
+ *  call-seq:
+ *     mod.public_class_method(symbol, ...)    => mod
+ *
+ *  Makes a list of existing class methods public.
+ */
+
+static VALUE
+rb_mod_public_method(int argc, VALUE *argv, VALUE obj)
+{
+    set_method_visibility(CLASS_OF(obj), argc, argv, NOEX_PUBLIC);
+    return obj;
+}
+
+/*
+ *  call-seq:
+ *     mod.private_class_method(symbol, ...)   => mod
+ *
+ *  Makes existing class methods private. Often used to hide the default
+ *  constructor <code>new</code>.
+ *
+ *     class SimpleSingleton  # Not thread safe
+ *       private_class_method :new
+ *       def SimpleSingleton.create(*args, &block)
+ *         @me = new(*args, &block) if ! @me
+ *         @me
+ *       end
+ *     end
+ */
+
+static VALUE
+rb_mod_private_method(int argc, VALUE *argv, VALUE obj)
+{
+    set_method_visibility(CLASS_OF(obj), argc, argv, NOEX_PRIVATE);
+    return obj;
+}
+
+/*
+ *  call-seq:
+ *     public
+ *     public(symbol, ...)
+ *
+ *  With no arguments, sets the default visibility for subsequently
+ *  defined methods to public. With arguments, sets the named methods to
+ *  have public visibility.
+ */
+
+static VALUE
+top_public(int argc, VALUE *argv)
+{
+    return rb_mod_public(argc, argv, rb_cObject);
+}
+
+static VALUE
+top_private(int argc, VALUE *argv)
+{
+    return rb_mod_private(argc, argv, rb_cObject);
+}
+
+/*
+ *  call-seq:
+ *     module_function(symbol, ...)    => self
+ *
+ *  Creates module functions for the named methods. These functions may
+ *  be called with the module as a receiver, and also become available
+ *  as instance methods to classes that mix in the module. Module
+ *  functions are copies of the original, and so may be changed
+ *  independently. The instance-method versions are made private. If
+ *  used with no arguments, subsequently defined methods become module
+ *  functions.
+ *
+ *     module Mod
+ *       def one
+ *         "This is one"
+ *       end
+ *       module_function :one
+ *     end
+ *     class Cls
+ *       include Mod
+ *       def callOne
+ *         one
+ *       end
+ *     end
+ *     Mod.one     #=> "This is one"
+ *     c = Cls.new
+ *     c.callOne   #=> "This is one"
+ *     module Mod
+ *       def one
+ *         "This is the new one"
+ *       end
+ *     end
+ *     Mod.one     #=> "This is one"
+ *     c.callOne   #=> "This is the new one"
+ */
+
+static VALUE
+rb_mod_modfunc(int argc, VALUE *argv, VALUE module)
+{
+    int i;
+    ID id;
+    NODE *fbody;
+
+    if (TYPE(module) != T_MODULE) {
+	rb_raise(rb_eTypeError, "module_function must be called for modules");
+    }
+
+    secure_visibility(module);
+    if (argc == 0) {
+	SCOPE_SET(NOEX_MODFUNC);
+	return module;
+    }
+
+    set_method_visibility(module, argc, argv, NOEX_PRIVATE);
+
+    for (i = 0; i < argc; i++) {
+	VALUE m = module;
+
+	id = rb_to_id(argv[i]);
+	for (;;) {
+	    fbody = search_method(m, id, &m);
+	    if (fbody == 0) {
+		fbody = search_method(rb_cObject, id, &m);
+	    }
+	    if (fbody == 0 || fbody->nd_body == 0) {
+		rb_bug("undefined method `%s'; can't happen", rb_id2name(id));
+	    }
+	    if (nd_type(fbody->nd_body->nd_body) != NODE_ZSUPER) {
+		break;		/* normal case: need not to follow 'super' link */
+	    }
+	    m = RCLASS_SUPER(m);
+	    if (!m)
+		break;
+	}
+	rb_add_method(rb_singleton_class(module), id, fbody->nd_body->nd_body,
+		      NOEX_PUBLIC);
+    }
+    return module;
+}
+
+/*
+ *  call-seq:
+ *     obj.respond_to?(symbol, include_private=false) => true or false
+ *
+ *  Returns +true+> if _obj_ responds to the given
+ *  method. Private methods are included in the search only if the
+ *  optional second parameter evaluates to +true+.
+ */
+
+static NODE *basic_respond_to = 0;
+
+int
+rb_obj_respond_to(VALUE obj, ID id, int priv)
+{
+    VALUE klass = CLASS_OF(obj);
+
+    if (rb_method_node(klass, idRespond_to) == basic_respond_to) {
+	return rb_method_boundp(klass, id, !priv);
+    }
+    else {
+	VALUE args[2];
+	int n = 0;
+	args[n++] = ID2SYM(id);
+	if (priv)
+	    args[n++] = Qtrue;
+	return RTEST(rb_funcall2(obj, idRespond_to, n, args));
+    }
+}
+
+int
+rb_respond_to(VALUE obj, ID id)
+{
+    return rb_obj_respond_to(obj, id, Qfalse);
+}
+
+/*
+ *  call-seq:
+ *     obj.respond_to?(symbol, include_private=false) => true or false
+ *
+ *  Returns +true+> if _obj_ responds to the given
+ *  method. Private methods are included in the search only if the
+ *  optional second parameter evaluates to +true+.
+ */
+
+static VALUE
+obj_respond_to(int argc, VALUE *argv, VALUE obj)
+{
+    VALUE mid, priv;
+    ID id;
+
+    rb_scan_args(argc, argv, "11", &mid, &priv);
+    id = rb_to_id(mid);
+    if (rb_method_boundp(CLASS_OF(obj), id, !RTEST(priv))) {
+	return Qtrue;
+    }
+    return Qfalse;
+}
+
+void
+Init_eval_method(void)
+{
+    rb_define_method(rb_mKernel, "respond_to?", obj_respond_to, -1);
+    basic_respond_to = rb_method_node(rb_cObject, idRespond_to);
+    rb_register_mark_object((VALUE)basic_respond_to);
+
+    rb_define_private_method(rb_cModule, "remove_method", rb_mod_remove_method, -1);
+    rb_define_private_method(rb_cModule, "undef_method", rb_mod_undef_method, -1);
+    rb_define_private_method(rb_cModule, "alias_method", rb_mod_alias_method, 2);
+    rb_define_private_method(rb_cModule, "public", rb_mod_public, -1);
+    rb_define_private_method(rb_cModule, "protected", rb_mod_protected, -1);
+    rb_define_private_method(rb_cModule, "private", rb_mod_private, -1);
+    rb_define_private_method(rb_cModule, "module_function", rb_mod_modfunc, -1);
+
+    rb_define_method(rb_cModule, "method_defined?", rb_mod_method_defined, 1);
+    rb_define_method(rb_cModule, "public_method_defined?", rb_mod_public_method_defined, 1);
+    rb_define_method(rb_cModule, "private_method_defined?", rb_mod_private_method_defined, 1);
+    rb_define_method(rb_cModule, "protected_method_defined?", rb_mod_protected_method_defined, 1);
+    rb_define_method(rb_cModule, "public_class_method", rb_mod_public_method, -1);
+    rb_define_method(rb_cModule, "private_class_method", rb_mod_private_method, -1);
+
+    rb_define_singleton_method(rb_vm_top_self(), "public", top_public, -1);
+    rb_define_singleton_method(rb_vm_top_self(), "private", top_private, -1);
+
+    object_id = rb_intern("object_id");
+    __send__ = rb_intern("__send__");
+    eqq = rb_intern("===");
+    each = rb_intern("each");
+    aref = rb_intern("[]");
+    aset = rb_intern("[]=");
+    match = rb_intern("=~");
+    missing = rb_intern("method_missing");
+    added = rb_intern("method_added");
+    singleton_added = rb_intern("singleton_method_added");
+    removed = rb_intern("method_removed");
+    singleton_removed = rb_intern("singleton_method_removed");
+    undefined = rb_intern("method_undefined");
+    singleton_undefined = rb_intern("singleton_method_undefined");
+}
+