summaryrefslogtreecommitdiff
path: root/eval.c
blob: 0bf83371755b83860f1103929ce215a1a86056c2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
/**********************************************************************

  eval.c -

  $Author$
  created at: Thu Jun 10 14:22:17 JST 1993

  Copyright (C) 1993-2007 Yukihiro Matsumoto
  Copyright (C) 2000  Network Applied Communication Laboratory, Inc.
  Copyright (C) 2000  Information-technology Promotion Agency, Japan

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

#include "eval_intern.h"
#include "iseq.h"
#include "gc.h"
#include "ruby/vm.h"
#include "ruby/encoding.h"
#include "internal.h"
#include "vm_core.h"
#include "probes_helper.h"

NORETURN(void rb_raise_jump(VALUE));

NODE *rb_vm_get_cref(const rb_iseq_t *, const VALUE *);

VALUE rb_eLocalJumpError;
VALUE rb_eSysStackError;

#define exception_error GET_VM()->special_exceptions[ruby_error_reenter]

#include "eval_error.c"
#include "eval_jump.c"

#define CLASS_OR_MODULE_P(obj) \
    (!SPECIAL_CONST_P(obj) && \
     (BUILTIN_TYPE(obj) == T_CLASS || BUILTIN_TYPE(obj) == T_MODULE))

/* Initializes the Ruby VM and builtin libraries.
 * @retval 0 if succeeded.
 * @retval non-zero an error occurred.
 */
int
ruby_setup(void)
{
    static int initialized = 0;
    int state;

    if (initialized)
	return 0;
    initialized = 1;

    ruby_init_stack((void *)&state);
    Init_BareVM();
    Init_heap();

    PUSH_TAG();
    if ((state = EXEC_TAG()) == 0) {
	rb_call_inits();
	ruby_prog_init();
	GET_VM()->running = 1;
    }
    POP_TAG();

    return state;
}

/* Calls ruby_setup() and check error.
 *
 * Prints errors and calls exit(3) if an error occurred.
 */
void
ruby_init(void)
{
    int state = ruby_setup();
    if (state) {
	error_print();
	exit(EXIT_FAILURE);
    }
}

/*! Processes command line arguments and compiles the Ruby source to execute.
 *
 * This function does:
 * \li  Processes the given command line flags and arguments for ruby(1)
 * \li compiles the source code from the given argument, -e or stdin, and
 * \li returns the compiled source as an opaque pointer to an internal data structure
 *
 * @return an opaque pointer to the compiled source or an internal special value.
 * @sa ruby_executable_node().
 */
void *
ruby_options(int argc, char **argv)
{
    int state;
    void *volatile iseq = 0;

    ruby_init_stack((void *)&iseq);
    PUSH_TAG();
    if ((state = EXEC_TAG()) == 0) {
	SAVE_ROOT_JMPBUF(GET_THREAD(), iseq = ruby_process_options(argc, argv));
    }
    else {
	rb_clear_trace_func();
	state = error_handle(state);
	iseq = (void *)INT2FIX(state);
    }
    POP_TAG();
    return iseq;
}

static void
ruby_finalize_0(void)
{
    PUSH_TAG();
    if (EXEC_TAG() == 0) {
	rb_trap_exit();
    }
    POP_TAG();
    rb_exec_end_proc();
    rb_clear_trace_func();
}

static void
ruby_finalize_1(void)
{
    ruby_sig_finalize();
    GET_THREAD()->errinfo = Qnil;
    rb_gc_call_finalizer_at_exit();
}

/** Runs the VM finalization processes.
 *
 * <code>END{}</code> and procs registered by <code>Kernel.#at_exit</code> are
 * executed here. See the Ruby language spec for more details.
 *
 * @note This function is allowed to raise an exception if an error occurred.
 */
void
ruby_finalize(void)
{
    ruby_finalize_0();
    ruby_finalize_1();
}

/** Destructs the VM.
 *
 * Runs the VM finalization processes as well as ruby_finalize(), and frees
 * resources used by the VM.
 *
 * @param ex Default value to the return value.
 * @return If an error occurred returns a non-zero. If otherwise, returns the
 *         given ex.
 * @note This function does not raise any exception.
 */
int
ruby_cleanup(volatile int ex)
{
    int state;
    volatile VALUE errs[2];
    rb_thread_t *th = GET_THREAD();
    int nerr;

    rb_threadptr_interrupt(th);
    rb_threadptr_check_signal(th);
    PUSH_TAG();
    if ((state = EXEC_TAG()) == 0) {
	SAVE_ROOT_JMPBUF(th, { RUBY_VM_CHECK_INTS(th); });
    }
    POP_TAG();

    errs[1] = th->errinfo;
    th->safe_level = 0;
    ruby_init_stack(&errs[STACK_UPPER(errs, 0, 1)]);

    PUSH_TAG();
    if ((state = EXEC_TAG()) == 0) {
	SAVE_ROOT_JMPBUF(th, ruby_finalize_0());
    }
    POP_TAG();

    /* protect from Thread#raise */
    th->status = THREAD_KILLED;

    errs[0] = th->errinfo;
    PUSH_TAG();
    if ((state = EXEC_TAG()) == 0) {
	SAVE_ROOT_JMPBUF(th, rb_thread_terminate_all());
    }
    else if (ex == 0) {
	ex = state;
    }
    th->errinfo = errs[1];
    ex = error_handle(ex);
    ruby_finalize_1();

    /* unlock again if finalizer took mutexes. */
    rb_threadptr_unlock_all_locking_mutexes(GET_THREAD());
    POP_TAG();
    rb_thread_stop_timer_thread(1);

#if EXIT_SUCCESS != 0 || EXIT_FAILURE != 1
    switch (ex) {
#if EXIT_SUCCESS != 0
      case 0: ex = EXIT_SUCCESS; break;
#endif
#if EXIT_FAILURE != 1
      case 1: ex = EXIT_FAILURE; break;
#endif
    }
#endif

    state = 0;
    for (nerr = 0; nerr < numberof(errs); ++nerr) {
	VALUE err = errs[nerr];

	if (!RTEST(err)) continue;

	/* th->errinfo contains a NODE while break'ing */
	if (RB_TYPE_P(err, T_NODE)) continue;

	if (rb_obj_is_kind_of(err, rb_eSystemExit)) {
	    ex = sysexit_status(err);
	    break;
	}
	else if (rb_obj_is_kind_of(err, rb_eSignal)) {
	    VALUE sig = rb_iv_get(err, "signo");
	    state = NUM2INT(sig);
	    break;
	}
	else if (ex == EXIT_SUCCESS) {
	    ex = EXIT_FAILURE;
	}
    }
    ruby_vm_destruct(GET_VM());
    if (state) ruby_default_signal(state);

    return ex;
}

static int
ruby_exec_internal(void *n)
{
    volatile int state;
    VALUE iseq = (VALUE)n;
    rb_thread_t *th = GET_THREAD();

    if (!n) return 0;

    PUSH_TAG();
    if ((state = EXEC_TAG()) == 0) {
	SAVE_ROOT_JMPBUF(th, {
	    th->base_block = 0;
	    rb_iseq_eval_main(iseq);
	});
    }
    POP_TAG();
    return state;
}

/*! Calls ruby_cleanup() and exits the process */
void
ruby_stop(int ex)
{
    exit(ruby_cleanup(ex));
}

/*! Checks the return value of ruby_options().
 * @param n return value of ruby_options().
 * @param status pointer to the exit status of this process.
 *
 * ruby_options() sometimes returns a special value to indicate this process
 * should immediately exit. This function checks if the case. Also stores the
 * exit status that the caller have to pass to exit(3) into
 * <code>*status</code>.
 *
 * @retval non-zero if the given opaque pointer is actually a compiled source.
 * @retval 0 if the given value is such a special value.
 */
int
ruby_executable_node(void *n, int *status)
{
    VALUE v = (VALUE)n;
    int s;

    switch (v) {
      case Qtrue:  s = EXIT_SUCCESS; break;
      case Qfalse: s = EXIT_FAILURE; break;
      default:
	if (!FIXNUM_P(v)) return TRUE;
	s = FIX2INT(v);
    }
    if (status) *status = s;
    return FALSE;
}

/*! Runs the given compiled source and exits this process.
 * @retval 0 if successfully run the source
 * @retval non-zero if an error occurred.
*/
int
ruby_run_node(void *n)
{
    int status;
    if (!ruby_executable_node(n, &status)) {
	ruby_cleanup(0);
	return status;
    }
    return ruby_cleanup(ruby_exec_node(n));
}

/*! Runs the given compiled source */
int
ruby_exec_node(void *n)
{
    ruby_init_stack((void *)&n);
    return ruby_exec_internal(n);
}

/*
 *  call-seq:
 *     Module.nesting    -> array
 *
 *  Returns the list of +Modules+ nested at the point of call.
 *
 *     module M1
 *       module M2
 *         $a = Module.nesting
 *       end
 *     end
 *     $a           #=> [M1::M2, M1]
 *     $a[0].name   #=> "M1::M2"
 */

static VALUE
rb_mod_nesting(void)
{
    VALUE ary = rb_ary_new();
    const NODE *cref = rb_vm_cref();

    while (cref && cref->nd_next) {
	VALUE klass = cref->nd_clss;
	if (!(cref->flags & NODE_FL_CREF_PUSHED_BY_EVAL) &&
	    !NIL_P(klass)) {
	    rb_ary_push(ary, klass);
	}
	cref = cref->nd_next;
    }
    return ary;
}

/*
 *  call-seq:
 *     Module.constants   -> array
 *     Module.constants(inherited)   -> array
 *
 *  In the first form, returns an array of the names of all
 *  constants accessible from the point of call.
 *  This list includes the names of all modules and classes
 *  defined in the global scope.
 *
 *     Module.constants.first(4)
 *        # => [:ARGF, :ARGV, :ArgumentError, :Array]
 *
 *     Module.constants.include?(:SEEK_SET)   # => false
 *
 *     class IO
 *       Module.constants.include?(:SEEK_SET) # => true
 *     end
 *
 *  The second form calls the instance method +constants+.
 */

static VALUE
rb_mod_s_constants(int argc, VALUE *argv, VALUE mod)
{
    const NODE *cref = rb_vm_cref();
    VALUE klass;
    VALUE cbase = 0;
    void *data = 0;

    if (argc > 0) {
	return rb_mod_constants(argc, argv, rb_cModule);
    }

    while (cref) {
	klass = cref->nd_clss;
	if (!(cref->flags & NODE_FL_CREF_PUSHED_BY_EVAL) &&
	    !NIL_P(klass)) {
	    data = rb_mod_const_at(cref->nd_clss, data);
	    if (!cbase) {
		cbase = klass;
	    }
	}
	cref = cref->nd_next;
    }

    if (cbase) {
	data = rb_mod_const_of(cbase, data);
    }
    return rb_const_list(data);
}

void
rb_frozen_class_p(VALUE klass)
{
    if (SPECIAL_CONST_P(klass)) {
      noclass:
	Check_Type(klass, T_CLASS);
    }
    if (OBJ_FROZEN(klass)) {
	const char *desc;

	if (FL_TEST(klass, FL_SINGLETON))
	    desc = "object";
	else {
	    switch (BUILTIN_TYPE(klass)) {
	      case T_MODULE:
	      case T_ICLASS:
		desc = "module";
		break;
	      case T_CLASS:
		desc = "class";
		break;
	      default:
		goto noclass;
	    }
	}
	rb_error_frozen(desc);
    }
}

NORETURN(static void rb_longjmp(int, volatile VALUE));

static void
setup_exception(rb_thread_t *th, int tag, volatile VALUE mesg)
{
    VALUE at;
    VALUE e;
    const char *file;
    volatile int line = 0;

    if (NIL_P(mesg)) {
	mesg = th->errinfo;
	if (INTERNAL_EXCEPTION_P(mesg)) JUMP_TAG(TAG_FATAL);
    }
    if (NIL_P(mesg)) {
	mesg = rb_exc_new(rb_eRuntimeError, 0, 0);
    }

    file = rb_sourcefile();
    if (file) line = rb_sourceline();
    if (file && !NIL_P(mesg)) {
	if (mesg == sysstack_error) {
	    at = rb_enc_sprintf(rb_usascii_encoding(), "%s:%d", file, line);
	    at = rb_ary_new3(1, at);
	    rb_iv_set(mesg, "bt", at);
	}
	else {
	    at = get_backtrace(mesg);
	    if (NIL_P(at)) {
		at = rb_vm_backtrace_object();
		if (OBJ_FROZEN(mesg)) {
		    mesg = rb_obj_dup(mesg);
		}
		set_backtrace(mesg, at);
	    }
	}
    }
    if (!NIL_P(mesg)) {
	th->errinfo = mesg;
    }

    if (RTEST(ruby_debug) && !NIL_P(e = th->errinfo) &&
	!rb_obj_is_kind_of(e, rb_eSystemExit)) {
	int status;

	PUSH_TAG();
	if ((status = EXEC_TAG()) == 0) {
	    RB_GC_GUARD(e) = rb_obj_as_string(e);
	    if (file && line) {
		warn_printf("Exception `%s' at %s:%d - %"PRIsVALUE"\n",
			    rb_obj_classname(th->errinfo), file, line, e);
	    }
	    else if (file) {
		warn_printf("Exception `%s' at %s - %"PRIsVALUE"\n",
			    rb_obj_classname(th->errinfo), file, e);
	    }
	    else {
		warn_printf("Exception `%s' - %"PRIsVALUE"\n",
			    rb_obj_classname(th->errinfo), e);
	    }
	}
	POP_TAG();
	if (status == TAG_FATAL && th->errinfo == exception_error) {
	    th->errinfo = mesg;
	}
	else if (status) {
	    rb_threadptr_reset_raised(th);
	    JUMP_TAG(status);
	}
    }

    if (rb_threadptr_set_raised(th)) {
	th->errinfo = exception_error;
	rb_threadptr_reset_raised(th);
	JUMP_TAG(TAG_FATAL);
    }

    if (tag != TAG_FATAL) {
	if (RUBY_DTRACE_RAISE_ENABLED()) {
	    RUBY_DTRACE_RAISE(rb_obj_classname(th->errinfo),
			      rb_sourcefile(),
			      rb_sourceline());
	}
	EXEC_EVENT_HOOK(th, RUBY_EVENT_RAISE, th->cfp->self, 0, 0, mesg);
    }
}

static void
rb_longjmp(int tag, volatile VALUE mesg)
{
    rb_thread_t *th = GET_THREAD();
    setup_exception(th, tag, mesg);
    rb_thread_raised_clear(th);
    JUMP_TAG(tag);
}

static VALUE make_exception(int argc, VALUE *argv, int isstr);

void
rb_exc_raise(VALUE mesg)
{
    if (!NIL_P(mesg)) {
	mesg = make_exception(1, &mesg, FALSE);
    }
    rb_longjmp(TAG_RAISE, mesg);
}

void
rb_exc_fatal(VALUE mesg)
{
    if (!NIL_P(mesg)) {
	mesg = make_exception(1, &mesg, FALSE);
    }
    rb_longjmp(TAG_FATAL, mesg);
}

void
rb_interrupt(void)
{
    rb_raise(rb_eInterrupt, "%s", "");
}

static VALUE get_errinfo(void);

/*
 *  call-seq:
 *     raise
 *     raise(string)
 *     raise(exception [, string [, array]])
 *     fail
 *     fail(string)
 *     fail(exception [, string [, array]])
 *
 *  With no arguments, raises the exception in <code>$!</code> or raises
 *  a <code>RuntimeError</code> if <code>$!</code> is +nil+.
 *  With a single +String+ argument, raises a
 *  +RuntimeError+ with the string as a message. Otherwise,
 *  the first parameter should be the name of an +Exception+
 *  class (or an object that returns an +Exception+ object when sent
 *  an +exception+ message). The optional second parameter sets the
 *  message associated with the exception, and the third parameter is an
 *  array of callback information. Exceptions are caught by the
 *  +rescue+ clause of <code>begin...end</code> blocks.
 *
 *     raise "Failed to create socket"
 *     raise ArgumentError, "No parameters", caller
 */

static VALUE
rb_f_raise(int argc, VALUE *argv)
{
    VALUE err;
    if (argc == 0) {
	err = get_errinfo();
	if (!NIL_P(err)) {
	    argc = 1;
	    argv = &err;
	}
    }
    rb_raise_jump(rb_make_exception(argc, argv));

    UNREACHABLE;
}

static VALUE
make_exception(int argc, VALUE *argv, int isstr)
{
    VALUE mesg, exc;
    ID exception;
    int n;

    mesg = Qnil;
    switch (argc) {
      case 0:
	break;
      case 1:
	exc = argv[0];
	if (NIL_P(exc))
	    break;
	if (isstr) {
	    mesg = rb_check_string_type(exc);
	    if (!NIL_P(mesg)) {
		mesg = rb_exc_new3(rb_eRuntimeError, mesg);
		break;
	    }
	}
	n = 0;
	goto exception_call;

      case 2:
      case 3:
	exc = argv[0];
	n = 1;
      exception_call:
	if (exc == sysstack_error) return exc;
	CONST_ID(exception, "exception");
	mesg = rb_check_funcall(exc, exception, n, argv+1);
	if (mesg == Qundef) {
	    rb_raise(rb_eTypeError, "exception class/object expected");
	}
	break;
      default:
	rb_check_arity(argc, 0, 3);
	break;
    }
    if (argc > 0) {
	if (!rb_obj_is_kind_of(mesg, rb_eException))
	    rb_raise(rb_eTypeError, "exception object expected");
	if (argc > 2)
	    set_backtrace(mesg, argv[2]);
    }

    return mesg;
}

VALUE
rb_make_exception(int argc, VALUE *argv)
{
    return make_exception(argc, argv, TRUE);
}

void
rb_raise_jump(VALUE mesg)
{
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = th->cfp;
    VALUE klass = cfp->me->klass;
    VALUE self = cfp->self;
    ID mid = cfp->me->called_id;

    th->cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(th->cfp);

    setup_exception(th, TAG_RAISE, mesg);

    EXEC_EVENT_HOOK(th, RUBY_EVENT_C_RETURN, self, mid, klass, Qnil);
    rb_thread_raised_clear(th);
    JUMP_TAG(TAG_RAISE);
}

void
rb_jump_tag(int tag)
{
    JUMP_TAG(tag);
}

int
rb_block_given_p(void)
{
    rb_thread_t *th = GET_THREAD();

    if (rb_vm_control_frame_block_ptr(th->cfp)) {
	return TRUE;
    }
    else {
	return FALSE;
    }
}

int
rb_iterator_p(void)
{
    return rb_block_given_p();
}

VALUE rb_eThreadError;

void
rb_need_block(void)
{
    if (!rb_block_given_p()) {
	rb_vm_localjump_error("no block given", Qnil, 0);
    }
}

VALUE
rb_rescue2(VALUE (* b_proc) (ANYARGS), VALUE data1,
	   VALUE (* r_proc) (ANYARGS), VALUE data2, ...)
{
    int state;
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = th->cfp;
    volatile VALUE result;
    volatile VALUE e_info = th->errinfo;
    va_list args;

    TH_PUSH_TAG(th);
    if ((state = TH_EXEC_TAG()) == 0) {
      retry_entry:
	result = (*b_proc) (data1);
    }
    else {
	th->cfp = cfp; /* restore */

	if (state == TAG_RAISE) {
	    int handle = FALSE;
	    VALUE eclass;

	    va_init_list(args, data2);
	    while ((eclass = va_arg(args, VALUE)) != 0) {
		if (rb_obj_is_kind_of(th->errinfo, eclass)) {
		    handle = TRUE;
		    break;
		}
	    }
	    va_end(args);

	    if (handle) {
		if (r_proc) {
		    PUSH_TAG();
		    if ((state = EXEC_TAG()) == 0) {
			result = (*r_proc) (data2, th->errinfo);
		    }
		    POP_TAG();
		    if (state == TAG_RETRY) {
			state = 0;
			th->errinfo = Qnil;
			goto retry_entry;
		    }
		}
		else {
		    result = Qnil;
		    state = 0;
		}
		if (state == 0) {
		    th->errinfo = e_info;
		}
	    }
	}
    }
    TH_POP_TAG();
    if (state)
	JUMP_TAG(state);

    return result;
}

VALUE
rb_rescue(VALUE (* b_proc)(ANYARGS), VALUE data1,
	  VALUE (* r_proc)(ANYARGS), VALUE data2)
{
    return rb_rescue2(b_proc, data1, r_proc, data2, rb_eStandardError,
		      (VALUE)0);
}

VALUE
rb_protect(VALUE (* proc) (VALUE), VALUE data, int * state)
{
    volatile VALUE result = Qnil;
    int status;
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = th->cfp;
    struct rb_vm_protect_tag protect_tag;
    rb_jmpbuf_t org_jmpbuf;

    protect_tag.prev = th->protect_tag;

    TH_PUSH_TAG(th);
    th->protect_tag = &protect_tag;
    MEMCPY(&org_jmpbuf, &(th)->root_jmpbuf, rb_jmpbuf_t, 1);
    if ((status = TH_EXEC_TAG()) == 0) {
	SAVE_ROOT_JMPBUF(th, result = (*proc) (data));
    }
    MEMCPY(&(th)->root_jmpbuf, &org_jmpbuf, rb_jmpbuf_t, 1);
    th->protect_tag = protect_tag.prev;
    TH_POP_TAG();

    if (state) {
	*state = status;
    }
    if (status != 0) {
	th->cfp = cfp;
	return Qnil;
    }

    return result;
}

VALUE
rb_ensure(VALUE (*b_proc)(ANYARGS), VALUE data1, VALUE (*e_proc)(ANYARGS), VALUE data2)
{
    int state;
    volatile VALUE result = Qnil;
    volatile VALUE errinfo;
    rb_thread_t *const th = GET_THREAD();

    PUSH_TAG();
    if ((state = EXEC_TAG()) == 0) {
	result = (*b_proc) (data1);
    }
    POP_TAG();
    /* TODO: fix me */
    /* retval = prot_tag ? prot_tag->retval : Qnil; */     /* save retval */
    errinfo = th->errinfo;
    (*e_proc) (data2);
    th->errinfo = errinfo;
    if (state)
	JUMP_TAG(state);
    return result;
}

static const rb_method_entry_t *
method_entry_of_iseq(rb_control_frame_t *cfp, rb_iseq_t *iseq)
{
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp_limit;

    cfp_limit = (rb_control_frame_t *)(th->stack + th->stack_size);
    while (cfp_limit > cfp) {
	if (cfp->iseq == iseq)
	    return cfp->me;
	cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
    }
    return 0;
}

static ID
frame_func_id(rb_control_frame_t *cfp)
{
    const rb_method_entry_t *me_local;
    rb_iseq_t *iseq = cfp->iseq;
    if (cfp->me) {
	return cfp->me->def->original_id;
    }
    while (iseq) {
	if (RUBY_VM_IFUNC_P(iseq)) {
	    NODE *ifunc = (NODE *)iseq;
	    if (ifunc->nd_aid) return ifunc->nd_aid;
	    return idIFUNC;
	}
	me_local = method_entry_of_iseq(cfp, iseq);
	if (me_local) {
	    cfp->me = me_local;
	    return me_local->def->original_id;
	}
	if (iseq->defined_method_id) {
	    return iseq->defined_method_id;
	}
	if (iseq->local_iseq == iseq) {
	    break;
	}
	iseq = iseq->parent_iseq;
    }
    return 0;
}

static ID
frame_called_id(rb_control_frame_t *cfp)
{
    const rb_method_entry_t *me_local;
    rb_iseq_t *iseq = cfp->iseq;
    if (cfp->me) {
	return cfp->me->called_id;
    }
    while (iseq) {
	if (RUBY_VM_IFUNC_P(iseq)) {
	    NODE *ifunc = (NODE *)iseq;
	    if (ifunc->nd_aid) return ifunc->nd_aid;
	    return idIFUNC;
	}
	me_local = method_entry_of_iseq(cfp, iseq);
	if (me_local) {
	    cfp->me = me_local;
	    return me_local->called_id;
	}
	if (iseq->defined_method_id) {
	    return iseq->defined_method_id;
	}
	if (iseq->local_iseq == iseq) {
	    break;
	}
	iseq = iseq->parent_iseq;
    }
    return 0;
}

ID
rb_frame_this_func(void)
{
    return frame_func_id(GET_THREAD()->cfp);
}

ID
rb_frame_callee(void)
{
    return frame_called_id(GET_THREAD()->cfp);
}

static rb_control_frame_t *
previous_frame(rb_thread_t *th)
{
    rb_control_frame_t *prev_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(th->cfp);
    /* check if prev_cfp can be accessible */
    if ((void *)(th->stack + th->stack_size) == (void *)(prev_cfp)) {
        return 0;
    }
    return prev_cfp;
}

static ID
prev_frame_callee(void)
{
    rb_control_frame_t *prev_cfp = previous_frame(GET_THREAD());
    if (!prev_cfp) return 0;
    return frame_called_id(prev_cfp);
}

static ID
prev_frame_func(void)
{
    rb_control_frame_t *prev_cfp = previous_frame(GET_THREAD());
    if (!prev_cfp) return 0;
    return frame_func_id(prev_cfp);
}

void
rb_frame_pop(void)
{
    rb_thread_t *th = GET_THREAD();
    th->cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(th->cfp);
}

/*
 *  call-seq:
 *     append_features(mod)   -> mod
 *
 *  When this module is included in another, Ruby calls
 *  <code>append_features</code> in this module, passing it the
 *  receiving module in _mod_. Ruby's default implementation is
 *  to add the constants, methods, and module variables of this module
 *  to _mod_ if this module has not already been added to
 *  _mod_ or one of its ancestors. See also <code>Module#include</code>.
 */

static VALUE
rb_mod_append_features(VALUE module, VALUE include)
{
    if (!CLASS_OR_MODULE_P(include)) {
	Check_Type(include, T_CLASS);
    }
    rb_include_module(include, module);

    return module;
}

/*
 *  call-seq:
 *     include(module, ...)    -> self
 *
 *  Invokes <code>Module.append_features</code> on each parameter in reverse order.
 */

static VALUE
rb_mod_include(int argc, VALUE *argv, VALUE module)
{
    int i;
    ID id_append_features, id_included;

    CONST_ID(id_append_features, "append_features");
    CONST_ID(id_included, "included");

    for (i = 0; i < argc; i++)
	Check_Type(argv[i], T_MODULE);
    while (argc--) {
	rb_funcall(argv[argc], id_append_features, 1, module);
	rb_funcall(argv[argc], id_included, 1, module);
    }
    return module;
}

/*
 *  call-seq:
 *     prepend_features(mod)   -> mod
 *
 *  When this module is prepended in another, Ruby calls
 *  <code>prepend_features</code> in this module, passing it the
 *  receiving module in _mod_. Ruby's default implementation is
 *  to overlay the constants, methods, and module variables of this module
 *  to _mod_ if this module has not already been added to
 *  _mod_ or one of its ancestors. See also <code>Module#prepend</code>.
 */

static VALUE
rb_mod_prepend_features(VALUE module, VALUE prepend)
{
    if (!CLASS_OR_MODULE_P(prepend)) {
	Check_Type(prepend, T_CLASS);
    }
    rb_prepend_module(prepend, module);

    return module;
}

/*
 *  call-seq:
 *     prepend(module, ...)    -> self
 *
 *  Invokes <code>Module.prepend_features</code> on each parameter in reverse order.
 */

static VALUE
rb_mod_prepend(int argc, VALUE *argv, VALUE module)
{
    int i;
    ID id_prepend_features, id_prepended;

    CONST_ID(id_prepend_features, "prepend_features");
    CONST_ID(id_prepended, "prepended");
    for (i = 0; i < argc; i++)
	Check_Type(argv[i], T_MODULE);
    while (argc--) {
	rb_funcall(argv[argc], id_prepend_features, 1, module);
	rb_funcall(argv[argc], id_prepended, 1, module);
    }
    return module;
}

static void
warn_refinements_once()
{
    static int warned = 0;

    if (warned)
	return;
    rb_warn("Refinements are experimental, and the behavior may change in future versions of Ruby!");
    warned = 1;
}

static VALUE
hidden_identity_hash_new()
{
    VALUE hash = rb_hash_new();

    rb_funcall(hash, rb_intern("compare_by_identity"), 0);
    RBASIC_CLEAR_CLASS(hash); /* hide from ObjectSpace */
    return hash;
}

void
rb_using_refinement(NODE *cref, VALUE klass, VALUE module)
{
    VALUE iclass, c, superclass = klass;

    Check_Type(klass, T_CLASS);
    Check_Type(module, T_MODULE);
    if (NIL_P(cref->nd_refinements)) {
	cref->nd_refinements = hidden_identity_hash_new();
    }
    else {
	if (cref->flags & NODE_FL_CREF_OMOD_SHARED) {
	    cref->nd_refinements = rb_hash_dup(cref->nd_refinements);
	    cref->flags &= ~NODE_FL_CREF_OMOD_SHARED;
	}
	if (!NIL_P(c = rb_hash_lookup(cref->nd_refinements, klass))) {
	    superclass = c;
	    while (c && RB_TYPE_P(c, T_ICLASS)) {
		if (RBASIC(c)->klass == module) {
		    /* already used refinement */
		    return;
		}
		c = RCLASS_SUPER(c);
	    }
	}
    }
    FL_SET(module, RMODULE_IS_OVERLAID);
    c = iclass = rb_include_class_new(module, superclass);
    RCLASS_REFINED_CLASS(c) = klass;

    RCLASS_M_TBL(OBJ_WB_UNPROTECT(c)) = RCLASS_M_TBL(OBJ_WB_UNPROTECT(module));

    module = RCLASS_SUPER(module);
    while (module && module != klass) {
	FL_SET(module, RMODULE_IS_OVERLAID);
	c = RCLASS_SET_SUPER(c, rb_include_class_new(module, RCLASS_SUPER(c)));
	RCLASS_REFINED_CLASS(c) = klass;
	module = RCLASS_SUPER(module);
    }
    rb_hash_aset(cref->nd_refinements, klass, iclass);
}

static int
using_refinement(VALUE klass, VALUE module, VALUE arg)
{
    NODE *cref = (NODE *) arg;

    rb_using_refinement(cref, klass, module);
    return ST_CONTINUE;
}

static void
using_module_recursive(NODE *cref, VALUE klass)
{
    ID id_refinements;
    VALUE super, module, refinements;

    super = RCLASS_SUPER(klass);
    if (super) {
	using_module_recursive(cref, super);
    }
    switch (BUILTIN_TYPE(klass)) {
    case T_MODULE:
	module = klass;
	break;

    case T_ICLASS:
	module = RBASIC(klass)->klass;
	break;

    default:
	rb_raise(rb_eTypeError, "wrong argument type %s (expected Module)",
		 rb_obj_classname(klass));
	break;
    }
    CONST_ID(id_refinements, "__refinements__");
    refinements = rb_attr_get(module, id_refinements);
    if (NIL_P(refinements)) return;
    rb_hash_foreach(refinements, using_refinement, (VALUE) cref);
}

void
rb_using_module(NODE *cref, VALUE module)
{
    Check_Type(module, T_MODULE);
    using_module_recursive(cref, module);
}

VALUE rb_refinement_module_get_refined_class(VALUE module)
{
    ID id_refined_class;

    CONST_ID(id_refined_class, "__refined_class__");
    return rb_attr_get(module, id_refined_class);
}

static void
add_activated_refinement(VALUE activated_refinements,
			 VALUE klass, VALUE refinement)
{
    VALUE iclass, c, superclass = klass;

    if (!NIL_P(c = rb_hash_lookup(activated_refinements, klass))) {
	superclass = c;
	while (c && RB_TYPE_P(c, T_ICLASS)) {
	    if (RBASIC(c)->klass == refinement) {
		/* already used refinement */
		return;
	    }
	    c = RCLASS_SUPER(c);
	}
    }
    FL_SET(refinement, RMODULE_IS_OVERLAID);
    c = iclass = rb_include_class_new(refinement, superclass);
    RCLASS_REFINED_CLASS(c) = klass;
    refinement = RCLASS_SUPER(refinement);
    while (refinement) {
	FL_SET(refinement, RMODULE_IS_OVERLAID);
	c = RCLASS_SET_SUPER(c, rb_include_class_new(refinement, RCLASS_SUPER(c)));
	RCLASS_REFINED_CLASS(c) = klass;
	refinement = RCLASS_SUPER(refinement);
    }
    rb_hash_aset(activated_refinements, klass, iclass);
}

VALUE rb_yield_refine_block(VALUE refinement, VALUE refinements);

/*
 *  call-seq:
 *     refine(klass) { block }   -> module
 *
 *  Refine <i>klass</i> in the receiver.
 *
 *  Returns an overlaid module.
 */

static VALUE
rb_mod_refine(VALUE module, VALUE klass)
{
    VALUE refinement;
    ID id_refinements, id_activated_refinements,
       id_refined_class, id_defined_at;
    VALUE refinements, activated_refinements;
    rb_thread_t *th = GET_THREAD();
    rb_block_t *block = rb_vm_control_frame_block_ptr(th->cfp);

    warn_refinements_once();
    if (!block) {
        rb_raise(rb_eArgError, "no block given");
    }
    if (block->proc) {
        rb_raise(rb_eArgError,
		 "can't pass a Proc as a block to Module#refine");
    }
    Check_Type(klass, T_CLASS);
    CONST_ID(id_refinements, "__refinements__");
    refinements = rb_attr_get(module, id_refinements);
    if (NIL_P(refinements)) {
	refinements = hidden_identity_hash_new();
	rb_ivar_set(module, id_refinements, refinements);
    }
    CONST_ID(id_activated_refinements, "__activated_refinements__");
    activated_refinements = rb_attr_get(module, id_activated_refinements);
    if (NIL_P(activated_refinements)) {
	activated_refinements = hidden_identity_hash_new();
	rb_ivar_set(module, id_activated_refinements,
		    activated_refinements);
    }
    refinement = rb_hash_lookup(refinements, klass);
    if (NIL_P(refinement)) {
	refinement = rb_module_new();
	RCLASS_SET_SUPER(refinement, klass);
	FL_SET(refinement, RMODULE_IS_REFINEMENT);
	CONST_ID(id_refined_class, "__refined_class__");
	rb_ivar_set(refinement, id_refined_class, klass);
	CONST_ID(id_defined_at, "__defined_at__");
	rb_ivar_set(refinement, id_defined_at, module);
	rb_hash_aset(refinements, klass, refinement);
	add_activated_refinement(activated_refinements, klass, refinement);
    }
    rb_yield_refine_block(refinement, activated_refinements);
    return refinement;
}

/*
 *  call-seq:
 *     using(module)    -> self
 *
 *  Import class refinements from <i>module</i> into the current class or
 *  module definition.
 */

static VALUE
mod_using(VALUE self, VALUE module)
{
    NODE *cref = rb_vm_cref();
    rb_control_frame_t *prev_cfp = previous_frame(GET_THREAD());

    warn_refinements_once();
    if (prev_frame_func()) {
	rb_raise(rb_eRuntimeError,
		 "Module#using is not permitted in methods");
    }
    if (prev_cfp && prev_cfp->self != self) {
	rb_raise(rb_eRuntimeError, "Module#using is not called on self");
    }
    Check_Type(module, T_MODULE);
    rb_using_module(cref, module);
    rb_clear_cache();
    return self;
}

void
rb_obj_call_init(VALUE obj, int argc, VALUE *argv)
{
    PASS_PASSED_BLOCK();
    rb_funcall2(obj, idInitialize, argc, argv);
}

void
rb_extend_object(VALUE obj, VALUE module)
{
    rb_include_module(rb_singleton_class(obj), module);
}

/*
 *  call-seq:
 *     extend_object(obj)    -> obj
 *
 *  Extends the specified object by adding this module's constants and
 *  methods (which are added as singleton methods). This is the callback
 *  method used by <code>Object#extend</code>.
 *
 *     module Picky
 *       def Picky.extend_object(o)
 *         if String === o
 *           puts "Can't add Picky to a String"
 *         else
 *           puts "Picky added to #{o.class}"
 *           super
 *         end
 *       end
 *     end
 *     (s = Array.new).extend Picky  # Call Object.extend
 *     (s = "quick brown fox").extend Picky
 *
 *  <em>produces:</em>
 *
 *     Picky added to Array
 *     Can't add Picky to a String
 */

static VALUE
rb_mod_extend_object(VALUE mod, VALUE obj)
{
    rb_extend_object(obj, mod);
    return obj;
}

/*
 *  call-seq:
 *     obj.extend(module, ...)    -> obj
 *
 *  Adds to _obj_ the instance methods from each module given as a
 *  parameter.
 *
 *     module Mod
 *       def hello
 *         "Hello from Mod.\n"
 *       end
 *     end
 *
 *     class Klass
 *       def hello
 *         "Hello from Klass.\n"
 *       end
 *     end
 *
 *     k = Klass.new
 *     k.hello         #=> "Hello from Klass.\n"
 *     k.extend(Mod)   #=> #<Klass:0x401b3bc8>
 *     k.hello         #=> "Hello from Mod.\n"
 */

static VALUE
rb_obj_extend(int argc, VALUE *argv, VALUE obj)
{
    int i;
    ID id_extend_object, id_extended;

    CONST_ID(id_extend_object, "extend_object");
    CONST_ID(id_extended, "extended");

    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
    for (i = 0; i < argc; i++)
	Check_Type(argv[i], T_MODULE);
    while (argc--) {
	rb_funcall(argv[argc], id_extend_object, 1, obj);
	rb_funcall(argv[argc], id_extended, 1, obj);
    }
    return obj;
}

/*
 *  call-seq:
 *     include(module, ...)   -> self
 *
 *  Invokes <code>Module.append_features</code>
 *  on each parameter in turn. Effectively adds the methods and constants
 *  in each module to the receiver.
 */

static VALUE
top_include(int argc, VALUE *argv, VALUE self)
{
    rb_thread_t *th = GET_THREAD();

    if (th->top_wrapper) {
	rb_warning("main.include in the wrapped load is effective only in wrapper module");
	return rb_mod_include(argc, argv, th->top_wrapper);
    }
    return rb_mod_include(argc, argv, rb_cObject);
}

/*
 *  call-seq:
 *     using(module)    -> self
 *
 *  Import class refinements from <i>module</i> into the scope where
 *  <code>using</code> is called.
 */

static VALUE
top_using(VALUE self, VALUE module)
{
    NODE *cref = rb_vm_cref();
    rb_control_frame_t *prev_cfp = previous_frame(GET_THREAD());

    warn_refinements_once();
    if (cref->nd_next || (prev_cfp && prev_cfp->me)) {
	rb_raise(rb_eRuntimeError,
		 "main.using is permitted only at toplevel");
    }
    Check_Type(module, T_MODULE);
    rb_using_module(cref, module);
    rb_clear_cache();
    return self;
}

static VALUE *
errinfo_place(rb_thread_t *th)
{
    rb_control_frame_t *cfp = th->cfp;
    rb_control_frame_t *end_cfp = RUBY_VM_END_CONTROL_FRAME(th);

    while (RUBY_VM_VALID_CONTROL_FRAME_P(cfp, end_cfp)) {
	if (RUBY_VM_NORMAL_ISEQ_P(cfp->iseq)) {
	    if (cfp->iseq->type == ISEQ_TYPE_RESCUE) {
		return &cfp->ep[-2];
	    }
	    else if (cfp->iseq->type == ISEQ_TYPE_ENSURE &&
		     !RB_TYPE_P(cfp->ep[-2], T_NODE) &&
		     !FIXNUM_P(cfp->ep[-2])) {
		return &cfp->ep[-2];
	    }
	}
	cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
    }
    return 0;
}

static VALUE
get_thread_errinfo(rb_thread_t *th)
{
    VALUE *ptr = errinfo_place(th);
    if (ptr) {
	return *ptr;
    }
    else {
	return th->errinfo;
    }
}

static VALUE
get_errinfo(void)
{
    return get_thread_errinfo(GET_THREAD());
}

static VALUE
errinfo_getter(ID id)
{
    return get_errinfo();
}

#if 0
static void
errinfo_setter(VALUE val, ID id, VALUE *var)
{
    if (!NIL_P(val) && !rb_obj_is_kind_of(val, rb_eException)) {
	rb_raise(rb_eTypeError, "assigning non-exception to $!");
    }
    else {
	VALUE *ptr = errinfo_place(GET_THREAD());
	if (ptr) {
	    *ptr = val;
	}
	else {
	    rb_raise(rb_eRuntimeError, "errinfo_setter: not in rescue clause.");
	}
    }
}
#endif

VALUE
rb_errinfo(void)
{
    rb_thread_t *th = GET_THREAD();
    return th->errinfo;
}

void
rb_set_errinfo(VALUE err)
{
    if (!NIL_P(err) && !rb_obj_is_kind_of(err, rb_eException)) {
	rb_raise(rb_eTypeError, "assigning non-exception to $!");
    }
    GET_THREAD()->errinfo = err;
}

VALUE
rb_rubylevel_errinfo(void)
{
    return get_errinfo();
}

static VALUE
errat_getter(ID id)
{
    VALUE err = get_errinfo();
    if (!NIL_P(err)) {
	return get_backtrace(err);
    }
    else {
	return Qnil;
    }
}

static void
errat_setter(VALUE val, ID id, VALUE *var)
{
    VALUE err = get_errinfo();
    if (NIL_P(err)) {
	rb_raise(rb_eArgError, "$! not set");
    }
    set_backtrace(err, val);
}

/*
 *  call-seq:
 *     __method__         -> symbol
 *
 *  Returns the name at the definition of the current method as a
 *  Symbol.
 *  If called outside of a method, it returns <code>nil</code>.
 *
 */

static VALUE
rb_f_method_name(void)
{
    ID fname = prev_frame_func(); /* need *method* ID */

    if (fname) {
	return ID2SYM(fname);
    }
    else {
	return Qnil;
    }
}

/*
 *  call-seq:
 *     __callee__         -> symbol
 *
 *  Returns the called name of the current method as a Symbol.
 *  If called outside of a method, it returns <code>nil</code>.
 *
 */

static VALUE
rb_f_callee_name(void)
{
    ID fname = prev_frame_callee(); /* need *callee* ID */

    if (fname) {
	return ID2SYM(fname);
    }
    else {
	return Qnil;
    }
}

/*
 *  call-seq:
 *     __dir__         -> string
 *
 *  Returns the canonicalized absolute path of the directory of the file from
 *  which this method is called. It means symlinks in the path is resolved.
 *  If <code>__FILE__</code> is <code>nil</code>, it returns <code>nil</code>.
 *  The return value equals to <code>File.dirname(File.realpath(__FILE__))</code>.
 *
 */
static VALUE
f_current_dirname(void)
{
    VALUE base = rb_current_realfilepath();
    if (NIL_P(base)) {
	return Qnil;
    }
    base = rb_file_dirname(base);
    return base;
}

void
Init_eval(void)
{
    rb_define_virtual_variable("$@", errat_getter, errat_setter);
    rb_define_virtual_variable("$!", errinfo_getter, 0);

    rb_define_global_function("raise", rb_f_raise, -1);
    rb_define_global_function("fail", rb_f_raise, -1);

    rb_define_global_function("global_variables", rb_f_global_variables, 0);	/* in variable.c */

    rb_define_global_function("__method__", rb_f_method_name, 0);
    rb_define_global_function("__callee__", rb_f_callee_name, 0);
    rb_define_global_function("__dir__", f_current_dirname, 0);

    rb_define_private_method(rb_cModule, "append_features", rb_mod_append_features, 1);
    rb_define_private_method(rb_cModule, "extend_object", rb_mod_extend_object, 1);
    rb_define_private_method(rb_cModule, "include", rb_mod_include, -1);
    rb_define_private_method(rb_cModule, "prepend_features", rb_mod_prepend_features, 1);
    rb_define_private_method(rb_cModule, "prepend", rb_mod_prepend, -1);
    rb_define_private_method(rb_cModule, "refine", rb_mod_refine, 1);
    rb_define_private_method(rb_cModule, "using", mod_using, 1);
    rb_undef_method(rb_cClass, "refine");

    rb_undef_method(rb_cClass, "module_function");

    Init_vm_eval();
    Init_eval_method();

    rb_define_singleton_method(rb_cModule, "nesting", rb_mod_nesting, 0);
    rb_define_singleton_method(rb_cModule, "constants", rb_mod_s_constants, -1);

    rb_define_private_method(rb_singleton_class(rb_vm_top_self()),
			     "include", top_include, -1);
    rb_define_private_method(rb_singleton_class(rb_vm_top_self()),
			     "using", top_using, 1);

    rb_define_method(rb_mKernel, "extend", rb_obj_extend, -1);

    rb_define_global_function("trace_var", rb_f_trace_var, -1);	/* in variable.c */
    rb_define_global_function("untrace_var", rb_f_untrace_var, -1);	/* in variable.c */

    exception_error = rb_exc_new3(rb_eFatal,
				  rb_obj_freeze(rb_str_new2("exception reentered")));
    OBJ_TAINT(exception_error);
    OBJ_FREEZE(exception_error);
}