summaryrefslogtreecommitdiffstats
path: root/src/glsl/ast_to_hir.cpp
blob: 3de754fa818064b8096b896a5ae1e8883cf7070a (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
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
/*
 * Copyright © 2010 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

/**
 * \file ast_to_hir.c
 * Convert abstract syntax to to high-level intermediate reprensentation (HIR).
 *
 * During the conversion to HIR, the majority of the symantic checking is
 * preformed on the program.  This includes:
 *
 *    * Symbol table management
 *    * Type checking
 *    * Function binding
 *
 * The majority of this work could be done during parsing, and the parser could
 * probably generate HIR directly.  However, this results in frequent changes
 * to the parser code.  Since we do not assume that every system this complier
 * is built on will have Flex and Bison installed, we have to store the code
 * generated by these tools in our version control system.  In other parts of
 * the system we've seen problems where a parser was changed but the generated
 * code was not committed, merge conflicts where created because two developers
 * had slightly different versions of Bison installed, etc.
 *
 * I have also noticed that running Bison generated parsers in GDB is very
 * irritating.  When you get a segfault on '$$ = $1->foo', you can't very
 * well 'print $1' in GDB.
 *
 * As a result, my preference is to put as little C code as possible in the
 * parser (and lexer) sources.
 */

#include "main/imports.h"
#include "glsl_symbol_table.h"
#include "glsl_parser_extras.h"
#include "ast.h"
#include "glsl_types.h"
#include "ir.h"

void
_mesa_ast_to_hir(exec_list *instructions, struct _mesa_glsl_parse_state *state)
{
   _mesa_glsl_initialize_variables(instructions, state);
   _mesa_glsl_initialize_functions(instructions, state);

   state->current_function = NULL;

   foreach_list_typed (ast_node, ast, link, & state->translation_unit)
      ast->hir(instructions, state);
}


/**
 * If a conversion is available, convert one operand to a different type
 *
 * The \c from \c ir_rvalue is converted "in place".
 *
 * \param to     Type that the operand it to be converted to
 * \param from   Operand that is being converted
 * \param state  GLSL compiler state
 *
 * \return
 * If a conversion is possible (or unnecessary), \c true is returned.
 * Otherwise \c false is returned.
 */
static bool
apply_implicit_conversion(const glsl_type *to, ir_rvalue * &from,
			  struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;
   if (to->base_type == from->type->base_type)
      return true;

   /* This conversion was added in GLSL 1.20.  If the compilation mode is
    * GLSL 1.10, the conversion is skipped.
    */
   if (state->language_version < 120)
      return false;

   /* From page 27 (page 33 of the PDF) of the GLSL 1.50 spec:
    *
    *    "There are no implicit array or structure conversions. For
    *    example, an array of int cannot be implicitly converted to an
    *    array of float. There are no implicit conversions between
    *    signed and unsigned integers."
    */
   /* FINISHME: The above comment is partially a lie.  There is int/uint
    * FINISHME: conversion for immediate constants.
    */
   if (!to->is_float() || !from->type->is_numeric())
      return false;

   /* Convert to a floating point type with the same number of components
    * as the original type - i.e. int to float, not int to vec4.
    */
   to = glsl_type::get_instance(GLSL_TYPE_FLOAT, from->type->vector_elements,
			        from->type->matrix_columns);

   switch (from->type->base_type) {
   case GLSL_TYPE_INT:
      from = new(ctx) ir_expression(ir_unop_i2f, to, from, NULL);
      break;
   case GLSL_TYPE_UINT:
      from = new(ctx) ir_expression(ir_unop_u2f, to, from, NULL);
      break;
   case GLSL_TYPE_BOOL:
      from = new(ctx) ir_expression(ir_unop_b2f, to, from, NULL);
      break;
   default:
      assert(0);
   }

   return true;
}


static const struct glsl_type *
arithmetic_result_type(ir_rvalue * &value_a, ir_rvalue * &value_b,
		       bool multiply,
		       struct _mesa_glsl_parse_state *state, YYLTYPE *loc)
{
   const glsl_type *type_a = value_a->type;
   const glsl_type *type_b = value_b->type;

   /* From GLSL 1.50 spec, page 56:
    *
    *    "The arithmetic binary operators add (+), subtract (-),
    *    multiply (*), and divide (/) operate on integer and
    *    floating-point scalars, vectors, and matrices."
    */
   if (!type_a->is_numeric() || !type_b->is_numeric()) {
      _mesa_glsl_error(loc, state,
		       "Operands to arithmetic operators must be numeric");
      return glsl_type::error_type;
   }


   /*    "If one operand is floating-point based and the other is
    *    not, then the conversions from Section 4.1.10 "Implicit
    *    Conversions" are applied to the non-floating-point-based operand."
    */
   if (!apply_implicit_conversion(type_a, value_b, state)
       && !apply_implicit_conversion(type_b, value_a, state)) {
      _mesa_glsl_error(loc, state,
		       "Could not implicitly convert operands to "
		       "arithmetic operator");
      return glsl_type::error_type;
   }
   type_a = value_a->type;
   type_b = value_b->type;

   /*    "If the operands are integer types, they must both be signed or
    *    both be unsigned."
    *
    * From this rule and the preceeding conversion it can be inferred that
    * both types must be GLSL_TYPE_FLOAT, or GLSL_TYPE_UINT, or GLSL_TYPE_INT.
    * The is_numeric check above already filtered out the case where either
    * type is not one of these, so now the base types need only be tested for
    * equality.
    */
   if (type_a->base_type != type_b->base_type) {
      _mesa_glsl_error(loc, state,
		       "base type mismatch for arithmetic operator");
      return glsl_type::error_type;
   }

   /*    "All arithmetic binary operators result in the same fundamental type
    *    (signed integer, unsigned integer, or floating-point) as the
    *    operands they operate on, after operand type conversion. After
    *    conversion, the following cases are valid
    *
    *    * The two operands are scalars. In this case the operation is
    *      applied, resulting in a scalar."
    */
   if (type_a->is_scalar() && type_b->is_scalar())
      return type_a;

   /*   "* One operand is a scalar, and the other is a vector or matrix.
    *      In this case, the scalar operation is applied independently to each
    *      component of the vector or matrix, resulting in the same size
    *      vector or matrix."
    */
   if (type_a->is_scalar()) {
      if (!type_b->is_scalar())
	 return type_b;
   } else if (type_b->is_scalar()) {
      return type_a;
   }

   /* All of the combinations of <scalar, scalar>, <vector, scalar>,
    * <scalar, vector>, <scalar, matrix>, and <matrix, scalar> have been
    * handled.
    */
   assert(!type_a->is_scalar());
   assert(!type_b->is_scalar());

   /*   "* The two operands are vectors of the same size. In this case, the
    *      operation is done component-wise resulting in the same size
    *      vector."
    */
   if (type_a->is_vector() && type_b->is_vector()) {
      if (type_a == type_b) {
	 return type_a;
      } else {
	 _mesa_glsl_error(loc, state,
			  "vector size mismatch for arithmetic operator");
	 return glsl_type::error_type;
      }
   }

   /* All of the combinations of <scalar, scalar>, <vector, scalar>,
    * <scalar, vector>, <scalar, matrix>, <matrix, scalar>, and
    * <vector, vector> have been handled.  At least one of the operands must
    * be matrix.  Further, since there are no integer matrix types, the base
    * type of both operands must be float.
    */
   assert(type_a->is_matrix() || type_b->is_matrix());
   assert(type_a->base_type == GLSL_TYPE_FLOAT);
   assert(type_b->base_type == GLSL_TYPE_FLOAT);

   /*   "* The operator is add (+), subtract (-), or divide (/), and the
    *      operands are matrices with the same number of rows and the same
    *      number of columns. In this case, the operation is done component-
    *      wise resulting in the same size matrix."
    *    * The operator is multiply (*), where both operands are matrices or
    *      one operand is a vector and the other a matrix. A right vector
    *      operand is treated as a column vector and a left vector operand as a
    *      row vector. In all these cases, it is required that the number of
    *      columns of the left operand is equal to the number of rows of the
    *      right operand. Then, the multiply (*) operation does a linear
    *      algebraic multiply, yielding an object that has the same number of
    *      rows as the left operand and the same number of columns as the right
    *      operand. Section 5.10 "Vector and Matrix Operations" explains in
    *      more detail how vectors and matrices are operated on."
    */
   if (! multiply) {
      if (type_a == type_b)
	 return type_a;
   } else {
      if (type_a->is_matrix() && type_b->is_matrix()) {
	 /* Matrix multiply.  The columns of A must match the rows of B.  Given
	  * the other previously tested constraints, this means the vector type
	  * of a row from A must be the same as the vector type of a column from
	  * B.
	  */
	 if (type_a->row_type() == type_b->column_type()) {
	    /* The resulting matrix has the number of columns of matrix B and
	     * the number of rows of matrix A.  We get the row count of A by
	     * looking at the size of a vector that makes up a column.  The
	     * transpose (size of a row) is done for B.
	     */
	    const glsl_type *const type =
	       glsl_type::get_instance(type_a->base_type,
				       type_a->column_type()->vector_elements,
				       type_b->row_type()->vector_elements);
	    assert(type != glsl_type::error_type);

	    return type;
	 }
      } else if (type_a->is_matrix()) {
	 /* A is a matrix and B is a column vector.  Columns of A must match
	  * rows of B.  Given the other previously tested constraints, this
	  * means the vector type of a row from A must be the same as the
	  * vector the type of B.
	  */
	 if (type_a->row_type() == type_b)
	    return type_b;
      } else {
	 assert(type_b->is_matrix());

	 /* A is a row vector and B is a matrix.  Columns of A must match rows
	  * of B.  Given the other previously tested constraints, this means
	  * the type of A must be the same as the vector type of a column from
	  * B.
	  */
	 if (type_a == type_b->column_type())
	    return type_a;
      }

      _mesa_glsl_error(loc, state, "size mismatch for matrix multiplication");
      return glsl_type::error_type;
   }


   /*    "All other cases are illegal."
    */
   _mesa_glsl_error(loc, state, "type mismatch");
   return glsl_type::error_type;
}


static const struct glsl_type *
unary_arithmetic_result_type(const struct glsl_type *type,
			     struct _mesa_glsl_parse_state *state, YYLTYPE *loc)
{
   /* From GLSL 1.50 spec, page 57:
    *
    *    "The arithmetic unary operators negate (-), post- and pre-increment
    *     and decrement (-- and ++) operate on integer or floating-point
    *     values (including vectors and matrices). All unary operators work
    *     component-wise on their operands. These result with the same type
    *     they operated on."
    */
   if (!type->is_numeric()) {
      _mesa_glsl_error(loc, state,
		       "Operands to arithmetic operators must be numeric");
      return glsl_type::error_type;
   }

   return type;
}


static const struct glsl_type *
modulus_result_type(const struct glsl_type *type_a,
		    const struct glsl_type *type_b,
		    struct _mesa_glsl_parse_state *state, YYLTYPE *loc)
{
   /* From GLSL 1.50 spec, page 56:
    *    "The operator modulus (%) operates on signed or unsigned integers or
    *    integer vectors. The operand types must both be signed or both be
    *    unsigned."
    */
   if (!type_a->is_integer() || !type_b->is_integer()
       || (type_a->base_type != type_b->base_type)) {
      _mesa_glsl_error(loc, state, "type mismatch");
      return glsl_type::error_type;
   }

   /*    "The operands cannot be vectors of differing size. If one operand is
    *    a scalar and the other vector, then the scalar is applied component-
    *    wise to the vector, resulting in the same type as the vector. If both
    *    are vectors of the same size, the result is computed component-wise."
    */
   if (type_a->is_vector()) {
      if (!type_b->is_vector()
	  || (type_a->vector_elements == type_b->vector_elements))
	 return type_a;
   } else
      return type_b;

   /*    "The operator modulus (%) is not defined for any other data types
    *    (non-integer types)."
    */
   _mesa_glsl_error(loc, state, "type mismatch");
   return glsl_type::error_type;
}


static const struct glsl_type *
relational_result_type(ir_rvalue * &value_a, ir_rvalue * &value_b,
		       struct _mesa_glsl_parse_state *state, YYLTYPE *loc)
{
   const glsl_type *type_a = value_a->type;
   const glsl_type *type_b = value_b->type;

   /* From GLSL 1.50 spec, page 56:
    *    "The relational operators greater than (>), less than (<), greater
    *    than or equal (>=), and less than or equal (<=) operate only on
    *    scalar integer and scalar floating-point expressions."
    */
   if (!type_a->is_numeric()
       || !type_b->is_numeric()
       || !type_a->is_scalar()
       || !type_b->is_scalar()) {
      _mesa_glsl_error(loc, state,
		       "Operands to relational operators must be scalar and "
		       "numeric");
      return glsl_type::error_type;
   }

   /*    "Either the operands' types must match, or the conversions from
    *    Section 4.1.10 "Implicit Conversions" will be applied to the integer
    *    operand, after which the types must match."
    */
   if (!apply_implicit_conversion(type_a, value_b, state)
       && !apply_implicit_conversion(type_b, value_a, state)) {
      _mesa_glsl_error(loc, state,
		       "Could not implicitly convert operands to "
		       "relational operator");
      return glsl_type::error_type;
   }
   type_a = value_a->type;
   type_b = value_b->type;

   if (type_a->base_type != type_b->base_type) {
      _mesa_glsl_error(loc, state, "base type mismatch");
      return glsl_type::error_type;
   }

   /*    "The result is scalar Boolean."
    */
   return glsl_type::bool_type;
}


/**
 * Validates that a value can be assigned to a location with a specified type
 *
 * Validates that \c rhs can be assigned to some location.  If the types are
 * not an exact match but an automatic conversion is possible, \c rhs will be
 * converted.
 *
 * \return
 * \c NULL if \c rhs cannot be assigned to a location with type \c lhs_type.
 * Otherwise the actual RHS to be assigned will be returned.  This may be
 * \c rhs, or it may be \c rhs after some type conversion.
 *
 * \note
 * In addition to being used for assignments, this function is used to
 * type-check return values.
 */
ir_rvalue *
validate_assignment(struct _mesa_glsl_parse_state *state,
		    const glsl_type *lhs_type, ir_rvalue *rhs)
{
   const glsl_type *rhs_type = rhs->type;

   /* If there is already some error in the RHS, just return it.  Anything
    * else will lead to an avalanche of error message back to the user.
    */
   if (rhs_type->is_error())
      return rhs;

   /* If the types are identical, the assignment can trivially proceed.
    */
   if (rhs_type == lhs_type)
      return rhs;

   /* If the array element types are the same and the size of the LHS is zero,
    * the assignment is okay.
    *
    * Note: Whole-array assignments are not permitted in GLSL 1.10, but this
    * is handled by ir_dereference::is_lvalue.
    */
   if (lhs_type->is_array() && rhs->type->is_array()
       && (lhs_type->element_type() == rhs->type->element_type())
       && (lhs_type->array_size() == 0)) {
      return rhs;
   }

   /* Check for implicit conversion in GLSL 1.20 */
   if (apply_implicit_conversion(lhs_type, rhs, state)) {
      rhs_type = rhs->type;
      if (rhs_type == lhs_type)
	 return rhs;
   }

   return NULL;
}

ir_rvalue *
do_assignment(exec_list *instructions, struct _mesa_glsl_parse_state *state,
	      ir_rvalue *lhs, ir_rvalue *rhs,
	      YYLTYPE lhs_loc)
{
   void *ctx = state;
   bool error_emitted = (lhs->type->is_error() || rhs->type->is_error());

   if (!error_emitted) {
      /* FINISHME: This does not handle 'foo.bar.a.b.c[5].d = 5' */
      if (!lhs->is_lvalue()) {
	 _mesa_glsl_error(& lhs_loc, state, "non-lvalue in assignment");
	 error_emitted = true;
      }
   }

   ir_rvalue *new_rhs = validate_assignment(state, lhs->type, rhs);
   if (new_rhs == NULL) {
      _mesa_glsl_error(& lhs_loc, state, "type mismatch");
   } else {
      rhs = new_rhs;

      /* If the LHS array was not declared with a size, it takes it size from
       * the RHS.  If the LHS is an l-value and a whole array, it must be a
       * dereference of a variable.  Any other case would require that the LHS
       * is either not an l-value or not a whole array.
       */
      if (lhs->type->array_size() == 0) {
	 ir_dereference *const d = lhs->as_dereference();

	 assert(d != NULL);

	 ir_variable *const var = d->variable_referenced();

	 assert(var != NULL);

	 if (var->max_array_access >= unsigned(rhs->type->array_size())) {
	    /* FINISHME: This should actually log the location of the RHS. */
	    _mesa_glsl_error(& lhs_loc, state, "array size must be > %u due to "
			     "previous access",
			     var->max_array_access);
	 }

	 var->type = glsl_type::get_array_instance(state,
						   lhs->type->element_type(),
						   rhs->type->array_size());
      }
   }

   /* Most callers of do_assignment (assign, add_assign, pre_inc/dec,
    * but not post_inc) need the converted assigned value as an rvalue
    * to handle things like:
    *
    * i = j += 1;
    *
    * So we always just store the computed value being assigned to a
    * temporary and return a deref of that temporary.  If the rvalue
    * ends up not being used, the temp will get copy-propagated out.
    */
   ir_variable *var = new(ctx) ir_variable(rhs->type, "assignment_tmp");
   ir_dereference_variable *deref_var = new(ctx) ir_dereference_variable(var);
   instructions->push_tail(var);
   instructions->push_tail(new(ctx) ir_assignment(deref_var,
						  rhs,
						  NULL));
   deref_var = new(ctx) ir_dereference_variable(var);

   instructions->push_tail(new(ctx) ir_assignment(lhs,
						  deref_var,
						  NULL));

   return new(ctx) ir_dereference_variable(var);
}


/**
 * Generate a new temporary and add its declaration to the instruction stream
 */
static ir_variable *
generate_temporary(const glsl_type *type, exec_list *instructions,
		   struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;
   char *name = (char *) malloc(sizeof(char) * 13);

   snprintf(name, 13, "tmp_%08X", state->temp_index);
   state->temp_index++;

   ir_variable *const var = new(ctx) ir_variable(type, name);
   instructions->push_tail(var);

   return var;
}


static ir_rvalue *
get_lvalue_copy(exec_list *instructions, ir_rvalue *lvalue)
{
   void *ctx = talloc_parent(lvalue);
   ir_variable *var;

   /* FINISHME: Give unique names to the temporaries. */
   var = new(ctx) ir_variable(lvalue->type, "_post_incdec_tmp");
   var->mode = ir_var_auto;

   instructions->push_tail(new(ctx) ir_assignment(new(ctx) ir_dereference_variable(var),
						  lvalue, NULL));

   /* Once we've created this temporary, mark it read only so it's no
    * longer considered an lvalue.
    */
   var->read_only = true;

   return new(ctx) ir_dereference_variable(var);
}


ir_rvalue *
ast_node::hir(exec_list *instructions,
	      struct _mesa_glsl_parse_state *state)
{
   (void) instructions;
   (void) state;

   return NULL;
}


ir_rvalue *
ast_expression::hir(exec_list *instructions,
		    struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;
   static const int operations[AST_NUM_OPERATORS] = {
      -1,               /* ast_assign doesn't convert to ir_expression. */
      -1,               /* ast_plus doesn't convert to ir_expression. */
      ir_unop_neg,
      ir_binop_add,
      ir_binop_sub,
      ir_binop_mul,
      ir_binop_div,
      ir_binop_mod,
      ir_binop_lshift,
      ir_binop_rshift,
      ir_binop_less,
      ir_binop_greater,
      ir_binop_lequal,
      ir_binop_gequal,
      ir_binop_equal,
      ir_binop_nequal,
      ir_binop_bit_and,
      ir_binop_bit_xor,
      ir_binop_bit_or,
      ir_unop_bit_not,
      ir_binop_logic_and,
      ir_binop_logic_xor,
      ir_binop_logic_or,
      ir_unop_logic_not,

      /* Note: The following block of expression types actually convert
       * to multiple IR instructions.
       */
      ir_binop_mul,     /* ast_mul_assign */
      ir_binop_div,     /* ast_div_assign */
      ir_binop_mod,     /* ast_mod_assign */
      ir_binop_add,     /* ast_add_assign */
      ir_binop_sub,     /* ast_sub_assign */
      ir_binop_lshift,  /* ast_ls_assign */
      ir_binop_rshift,  /* ast_rs_assign */
      ir_binop_bit_and, /* ast_and_assign */
      ir_binop_bit_xor, /* ast_xor_assign */
      ir_binop_bit_or,  /* ast_or_assign */

      -1,               /* ast_conditional doesn't convert to ir_expression. */
      ir_binop_add,     /* ast_pre_inc. */
      ir_binop_sub,     /* ast_pre_dec. */
      ir_binop_add,     /* ast_post_inc. */
      ir_binop_sub,     /* ast_post_dec. */
      -1,               /* ast_field_selection doesn't conv to ir_expression. */
      -1,               /* ast_array_index doesn't convert to ir_expression. */
      -1,               /* ast_function_call doesn't conv to ir_expression. */
      -1,               /* ast_identifier doesn't convert to ir_expression. */
      -1,               /* ast_int_constant doesn't convert to ir_expression. */
      -1,               /* ast_uint_constant doesn't conv to ir_expression. */
      -1,               /* ast_float_constant doesn't conv to ir_expression. */
      -1,               /* ast_bool_constant doesn't conv to ir_expression. */
      -1,               /* ast_sequence doesn't convert to ir_expression. */
   };
   ir_rvalue *result = NULL;
   ir_rvalue *op[2];
   const struct glsl_type *type = glsl_type::error_type;
   bool error_emitted = false;
   YYLTYPE loc;

   loc = this->get_location();

   switch (this->oper) {
   case ast_assign: {
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);

      result = do_assignment(instructions, state, op[0], op[1],
			     this->subexpressions[0]->get_location());
      error_emitted = result->type->is_error();
      type = result->type;
      break;
   }

   case ast_plus:
      op[0] = this->subexpressions[0]->hir(instructions, state);

      error_emitted = op[0]->type->is_error();
      if (type->is_error())
	 op[0]->type = type;

      result = op[0];
      break;

   case ast_neg:
      op[0] = this->subexpressions[0]->hir(instructions, state);

      type = unary_arithmetic_result_type(op[0]->type, state, & loc);

      error_emitted = type->is_error();

      result = new(ctx) ir_expression(operations[this->oper], type,
				      op[0], NULL);
      break;

   case ast_add:
   case ast_sub:
   case ast_mul:
   case ast_div:
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);

      type = arithmetic_result_type(op[0], op[1],
				    (this->oper == ast_mul),
				    state, & loc);
      error_emitted = type->is_error();

      result = new(ctx) ir_expression(operations[this->oper], type,
				      op[0], op[1]);
      break;

   case ast_mod:
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);

      type = modulus_result_type(op[0]->type, op[1]->type, state, & loc);

      assert(operations[this->oper] == ir_binop_mod);

      result = new(ctx) ir_expression(operations[this->oper], type,
				      op[0], op[1]);
      error_emitted = type->is_error();
      break;

   case ast_lshift:
   case ast_rshift:
      _mesa_glsl_error(& loc, state, "FINISHME: implement bit-shift operators");
      error_emitted = true;
      break;

   case ast_less:
   case ast_greater:
   case ast_lequal:
   case ast_gequal:
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);

      type = relational_result_type(op[0], op[1], state, & loc);

      /* The relational operators must either generate an error or result
       * in a scalar boolean.  See page 57 of the GLSL 1.50 spec.
       */
      assert(type->is_error()
	     || ((type->base_type == GLSL_TYPE_BOOL)
		 && type->is_scalar()));

      result = new(ctx) ir_expression(operations[this->oper], type,
				      op[0], op[1]);
      error_emitted = type->is_error();
      break;

   case ast_nequal:
   case ast_equal:
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);

      /* From page 58 (page 64 of the PDF) of the GLSL 1.50 spec:
       *
       *    "The equality operators equal (==), and not equal (!=)
       *    operate on all types. They result in a scalar Boolean. If
       *    the operand types do not match, then there must be a
       *    conversion from Section 4.1.10 "Implicit Conversions"
       *    applied to one operand that can make them match, in which
       *    case this conversion is done."
       */
      if ((!apply_implicit_conversion(op[0]->type, op[1], state)
	   && !apply_implicit_conversion(op[1]->type, op[0], state))
	  || (op[0]->type != op[1]->type)) {
	 _mesa_glsl_error(& loc, state, "operands of `%s' must have the same "
			  "type", (this->oper == ast_equal) ? "==" : "!=");
	 error_emitted = true;
      } else if ((state->language_version <= 110)
		 && (op[0]->type->is_array() || op[1]->type->is_array())) {
	 _mesa_glsl_error(& loc, state, "array comparisons forbidden in "
			  "GLSL 1.10");
	 error_emitted = true;
      }

      result = new(ctx) ir_expression(operations[this->oper], glsl_type::bool_type,
				      op[0], op[1]);
      type = glsl_type::bool_type;

      assert(result->type == glsl_type::bool_type);
      break;

   case ast_bit_and:
   case ast_bit_xor:
   case ast_bit_or:
   case ast_bit_not:
      _mesa_glsl_error(& loc, state, "FINISHME: implement bit-wise operators");
      error_emitted = true;
      break;

   case ast_logic_and: {
      op[0] = this->subexpressions[0]->hir(instructions, state);

      if (!op[0]->type->is_boolean() || !op[0]->type->is_scalar()) {
	 YYLTYPE loc = this->subexpressions[0]->get_location();

	 _mesa_glsl_error(& loc, state, "LHS of `%s' must be scalar boolean",
			  operator_string(this->oper));
	 error_emitted = true;
      }

      ir_constant *op0_const = op[0]->constant_expression_value();
      if (op0_const) {
	 if (op0_const->value.b[0]) {
	    op[1] = this->subexpressions[1]->hir(instructions, state);

	    if (!op[1]->type->is_boolean() || !op[1]->type->is_scalar()) {
	       YYLTYPE loc = this->subexpressions[1]->get_location();

	       _mesa_glsl_error(& loc, state,
				"RHS of `%s' must be scalar boolean",
				operator_string(this->oper));
	       error_emitted = true;
	    }
	    result = op[1];
	 } else {
	    result = op0_const;
	 }
	 type = glsl_type::bool_type;
      } else {
	 ir_if *const stmt = new(ctx) ir_if(op[0]);
	 instructions->push_tail(stmt);

	 op[1] = this->subexpressions[1]->hir(&stmt->then_instructions, state);

	 if (!op[1]->type->is_boolean() || !op[1]->type->is_scalar()) {
	    YYLTYPE loc = this->subexpressions[1]->get_location();

	    _mesa_glsl_error(& loc, state,
			     "RHS of `%s' must be scalar boolean",
			     operator_string(this->oper));
	    error_emitted = true;
	 }

	 ir_variable *const tmp = generate_temporary(glsl_type::bool_type,
						     instructions, state);

	 ir_dereference *const then_deref = new(ctx) ir_dereference_variable(tmp);
	 ir_assignment *const then_assign =
	    new(ctx) ir_assignment(then_deref, op[1], NULL);
	 stmt->then_instructions.push_tail(then_assign);

	 ir_dereference *const else_deref = new(ctx) ir_dereference_variable(tmp);
	 ir_assignment *const else_assign =
	    new(ctx) ir_assignment(else_deref, new(ctx) ir_constant(false), NULL);
	 stmt->else_instructions.push_tail(else_assign);

	 result = new(ctx) ir_dereference_variable(tmp);
	 type = tmp->type;
      }
      break;
   }

   case ast_logic_or: {
      op[0] = this->subexpressions[0]->hir(instructions, state);

      if (!op[0]->type->is_boolean() || !op[0]->type->is_scalar()) {
	 YYLTYPE loc = this->subexpressions[0]->get_location();

	 _mesa_glsl_error(& loc, state, "LHS of `%s' must be scalar boolean",
			  operator_string(this->oper));
	 error_emitted = true;
      }

      ir_constant *op0_const = op[0]->constant_expression_value();
      if (op0_const) {
	 if (op0_const->value.b[0]) {
	    result = op0_const;
	 } else {
	    op[1] = this->subexpressions[1]->hir(instructions, state);

	    if (!op[1]->type->is_boolean() || !op[1]->type->is_scalar()) {
	       YYLTYPE loc = this->subexpressions[1]->get_location();

	       _mesa_glsl_error(& loc, state,
				"RHS of `%s' must be scalar boolean",
				operator_string(this->oper));
	       error_emitted = true;
	    }
	    result = op[1];
	 }
	 type = glsl_type::bool_type;
      } else {
	 ir_if *const stmt = new(ctx) ir_if(op[0]);
	 instructions->push_tail(stmt);

	 ir_variable *const tmp = generate_temporary(glsl_type::bool_type,
						     instructions, state);

	 op[1] = this->subexpressions[1]->hir(&stmt->then_instructions, state);

	 if (!op[1]->type->is_boolean() || !op[1]->type->is_scalar()) {
	    YYLTYPE loc = this->subexpressions[1]->get_location();

	    _mesa_glsl_error(& loc, state, "RHS of `%s' must be scalar boolean",
			     operator_string(this->oper));
	    error_emitted = true;
	 }

	 ir_dereference *const then_deref = new(ctx) ir_dereference_variable(tmp);
	 ir_assignment *const then_assign =
	    new(ctx) ir_assignment(then_deref, new(ctx) ir_constant(true), NULL);
	 stmt->then_instructions.push_tail(then_assign);

	 ir_dereference *const else_deref = new(ctx) ir_dereference_variable(tmp);
	 ir_assignment *const else_assign =
	    new(ctx) ir_assignment(else_deref, op[1], NULL);
	 stmt->else_instructions.push_tail(else_assign);

	 result = new(ctx) ir_dereference_variable(tmp);
	 type = tmp->type;
      }
      break;
   }

   case ast_logic_xor:
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);


      result = new(ctx) ir_expression(operations[this->oper], glsl_type::bool_type,
				      op[0], op[1]);
      type = glsl_type::bool_type;
      break;

   case ast_logic_not:
      op[0] = this->subexpressions[0]->hir(instructions, state);

      if (!op[0]->type->is_boolean() || !op[0]->type->is_scalar()) {
	 YYLTYPE loc = this->subexpressions[0]->get_location();

	 _mesa_glsl_error(& loc, state,
			  "operand of `!' must be scalar boolean");
	 error_emitted = true;
      }

      result = new(ctx) ir_expression(operations[this->oper], glsl_type::bool_type,
				      op[0], NULL);
      type = glsl_type::bool_type;
      break;

   case ast_mul_assign:
   case ast_div_assign:
   case ast_add_assign:
   case ast_sub_assign: {
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);

      type = arithmetic_result_type(op[0], op[1],
				    (this->oper == ast_mul_assign),
				    state, & loc);

      ir_rvalue *temp_rhs = new(ctx) ir_expression(operations[this->oper], type,
						   op[0], op[1]);

      result = do_assignment(instructions, state,
			     op[0]->clone(NULL), temp_rhs,
			     this->subexpressions[0]->get_location());
      type = result->type;
      error_emitted = (op[0]->type->is_error());

      /* GLSL 1.10 does not allow array assignment.  However, we don't have to
       * explicitly test for this because none of the binary expression
       * operators allow array operands either.
       */

      break;
   }

   case ast_mod_assign: {
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);

      type = modulus_result_type(op[0]->type, op[1]->type, state, & loc);

      assert(operations[this->oper] == ir_binop_mod);

      struct ir_rvalue *temp_rhs;
      temp_rhs = new(ctx) ir_expression(operations[this->oper], type,
					op[0], op[1]);

      result = do_assignment(instructions, state,
			     op[0]->clone(NULL), temp_rhs,
			     this->subexpressions[0]->get_location());
      type = result->type;
      error_emitted = type->is_error();
      break;
   }

   case ast_ls_assign:
   case ast_rs_assign:
      _mesa_glsl_error(& loc, state,
		       "FINISHME: implement bit-shift assignment operators");
      error_emitted = true;
      break;

   case ast_and_assign:
   case ast_xor_assign:
   case ast_or_assign:
      _mesa_glsl_error(& loc, state,
		       "FINISHME: implement logic assignment operators");
      error_emitted = true;
      break;

   case ast_conditional: {
      op[0] = this->subexpressions[0]->hir(instructions, state);

      /* From page 59 (page 65 of the PDF) of the GLSL 1.50 spec:
       *
       *    "The ternary selection operator (?:). It operates on three
       *    expressions (exp1 ? exp2 : exp3). This operator evaluates the
       *    first expression, which must result in a scalar Boolean."
       */
      if (!op[0]->type->is_boolean() || !op[0]->type->is_scalar()) {
	 YYLTYPE loc = this->subexpressions[0]->get_location();

	 _mesa_glsl_error(& loc, state, "?: condition must be scalar boolean");
	 error_emitted = true;
      }

      /* The :? operator is implemented by generating an anonymous temporary
       * followed by an if-statement.  The last instruction in each branch of
       * the if-statement assigns a value to the anonymous temporary.  This
       * temporary is the r-value of the expression.
       */
      exec_list then_instructions;
      exec_list else_instructions;

      op[1] = this->subexpressions[1]->hir(&then_instructions, state);
      op[2] = this->subexpressions[2]->hir(&else_instructions, state);

      /* From page 59 (page 65 of the PDF) of the GLSL 1.50 spec:
       *
       *     "The second and third expressions can be any type, as
       *     long their types match, or there is a conversion in
       *     Section 4.1.10 "Implicit Conversions" that can be applied
       *     to one of the expressions to make their types match. This
       *     resulting matching type is the type of the entire
       *     expression."
       */
      if ((!apply_implicit_conversion(op[1]->type, op[2], state)
	   && !apply_implicit_conversion(op[2]->type, op[1], state))
	  || (op[1]->type != op[2]->type)) {
	 YYLTYPE loc = this->subexpressions[1]->get_location();

	 _mesa_glsl_error(& loc, state, "Second and third operands of ?: "
			  "operator must have matching types.");
	 error_emitted = true;
	 type = glsl_type::error_type;
      } else {
	 type = op[1]->type;
      }

      ir_constant *cond_val = op[0]->constant_expression_value();
      ir_constant *then_val = op[1]->constant_expression_value();
      ir_constant *else_val = op[2]->constant_expression_value();

      if (then_instructions.is_empty()
	  && else_instructions.is_empty()
	  && (cond_val != NULL) && (then_val != NULL) && (else_val != NULL)) {
	 result = (cond_val->value.b[0]) ? then_val : else_val;
      } else {
	 ir_variable *const tmp = generate_temporary(type,
						     instructions, state);

	 ir_if *const stmt = new(ctx) ir_if(op[0]);
	 instructions->push_tail(stmt);

	 then_instructions.move_nodes_to(& stmt->then_instructions);
	 ir_dereference *const then_deref =
	    new(ctx) ir_dereference_variable(tmp);
	 ir_assignment *const then_assign =
	    new(ctx) ir_assignment(then_deref, op[1], NULL);
	 stmt->then_instructions.push_tail(then_assign);

	 else_instructions.move_nodes_to(& stmt->else_instructions);
	 ir_dereference *const else_deref =
	    new(ctx) ir_dereference_variable(tmp);
	 ir_assignment *const else_assign =
	    new(ctx) ir_assignment(else_deref, op[2], NULL);
	 stmt->else_instructions.push_tail(else_assign);

	 result = new(ctx) ir_dereference_variable(tmp);
      }
      break;
   }

   case ast_pre_inc:
   case ast_pre_dec: {
      op[0] = this->subexpressions[0]->hir(instructions, state);
      if (op[0]->type->base_type == GLSL_TYPE_FLOAT)
	 op[1] = new(ctx) ir_constant(1.0f);
      else
	 op[1] = new(ctx) ir_constant(1);

      type = arithmetic_result_type(op[0], op[1], false, state, & loc);

      struct ir_rvalue *temp_rhs;
      temp_rhs = new(ctx) ir_expression(operations[this->oper], type,
					op[0], op[1]);

      result = do_assignment(instructions, state,
			     op[0]->clone(NULL), temp_rhs,
			     this->subexpressions[0]->get_location());
      type = result->type;
      error_emitted = op[0]->type->is_error();
      break;
   }

   case ast_post_inc:
   case ast_post_dec: {
      op[0] = this->subexpressions[0]->hir(instructions, state);
      if (op[0]->type->base_type == GLSL_TYPE_FLOAT)
	 op[1] = new(ctx) ir_constant(1.0f);
      else
	 op[1] = new(ctx) ir_constant(1);

      error_emitted = op[0]->type->is_error() || op[1]->type->is_error();

      type = arithmetic_result_type(op[0], op[1], false, state, & loc);

      struct ir_rvalue *temp_rhs;
      temp_rhs = new(ctx) ir_expression(operations[this->oper], type,
					op[0], op[1]);

      /* Get a temporary of a copy of the lvalue before it's modified.
       * This may get thrown away later.
       */
      result = get_lvalue_copy(instructions, op[0]->clone(NULL));

      (void)do_assignment(instructions, state,
			  op[0]->clone(NULL), temp_rhs,
			  this->subexpressions[0]->get_location());

      type = result->type;
      error_emitted = op[0]->type->is_error();
      break;
   }

   case ast_field_selection:
      result = _mesa_ast_field_selection_to_hir(this, instructions, state);
      type = result->type;
      break;

   case ast_array_index: {
      YYLTYPE index_loc = subexpressions[1]->get_location();

      op[0] = subexpressions[0]->hir(instructions, state);
      op[1] = subexpressions[1]->hir(instructions, state);

      error_emitted = op[0]->type->is_error() || op[1]->type->is_error();

      ir_rvalue *const array = op[0];

      result = new(ctx) ir_dereference_array(op[0], op[1]);

      /* Do not use op[0] after this point.  Use array.
       */
      op[0] = NULL;


      if (error_emitted)
	 break;

      if (!array->type->is_array()
	  && !array->type->is_matrix()
	  && !array->type->is_vector()) {
	 _mesa_glsl_error(& index_loc, state,
			  "cannot dereference non-array / non-matrix / "
			  "non-vector");
	 error_emitted = true;
      }

      if (!op[1]->type->is_integer()) {
	 _mesa_glsl_error(& index_loc, state,
			  "array index must be integer type");
	 error_emitted = true;
      } else if (!op[1]->type->is_scalar()) {
	 _mesa_glsl_error(& index_loc, state,
			  "array index must be scalar");
	 error_emitted = true;
      }

      /* If the array index is a constant expression and the array has a
       * declared size, ensure that the access is in-bounds.  If the array
       * index is not a constant expression, ensure that the array has a
       * declared size.
       */
      ir_constant *const const_index = op[1]->constant_expression_value();
      if (const_index != NULL) {
	 const int idx = const_index->value.i[0];
	 const char *type_name;
	 unsigned bound = 0;

	 if (array->type->is_matrix()) {
	    type_name = "matrix";
	 } else if (array->type->is_vector()) {
	    type_name = "vector";
	 } else {
	    type_name = "array";
	 }

	 /* From page 24 (page 30 of the PDF) of the GLSL 1.50 spec:
	  *
	  *    "It is illegal to declare an array with a size, and then
	  *    later (in the same shader) index the same array with an
	  *    integral constant expression greater than or equal to the
	  *    declared size. It is also illegal to index an array with a
	  *    negative constant expression."
	  */
	 if (array->type->is_matrix()) {
	    if (array->type->row_type()->vector_elements <= idx) {
	       bound = array->type->row_type()->vector_elements;
	    }
	 } else if (array->type->is_vector()) {
	    if (array->type->vector_elements <= idx) {
	       bound = array->type->vector_elements;
	    }
	 } else {
	    if ((array->type->array_size() > 0)
		&& (array->type->array_size() <= idx)) {
	       bound = array->type->array_size();
	    }
	 }

	 if (bound > 0) {
	    _mesa_glsl_error(& loc, state, "%s index must be < %u",
			     type_name, bound);
	    error_emitted = true;
	 } else if (idx < 0) {
	    _mesa_glsl_error(& loc, state, "%s index must be >= 0",
			     type_name);
	    error_emitted = true;
	 }

	 if (array->type->is_array()) {
	    /* If the array is a variable dereference, it dereferences the
	     * whole array, by definition.  Use this to get the variable.
	     *
	     * FINISHME: Should some methods for getting / setting / testing
	     * FINISHME: array access limits be added to ir_dereference?
	     */
	    ir_variable *const v = array->whole_variable_referenced();
	    if ((v != NULL) && (unsigned(idx) > v->max_array_access))
	       v->max_array_access = idx;
	 }
      }

      if (error_emitted)
	 result->type = glsl_type::error_type;

      type = result->type;
      break;
   }

   case ast_function_call:
      /* Should *NEVER* get here.  ast_function_call should always be handled
       * by ast_function_expression::hir.
       */
      assert(0);
      break;

   case ast_identifier: {
      /* ast_identifier can appear several places in a full abstract syntax
       * tree.  This particular use must be at location specified in the grammar
       * as 'variable_identifier'.
       */
      ir_variable *var = 
	 state->symbols->get_variable(this->primary_expression.identifier);

      result = new(ctx) ir_dereference_variable(var);

      if (var != NULL) {
	 type = result->type;
      } else {
	 _mesa_glsl_error(& loc, state, "`%s' undeclared",
			  this->primary_expression.identifier);

	 error_emitted = true;
      }
      break;
   }

   case ast_int_constant:
      type = glsl_type::int_type;
      result = new(ctx) ir_constant(this->primary_expression.int_constant);
      break;

   case ast_uint_constant:
      type = glsl_type::uint_type;
      result = new(ctx) ir_constant(this->primary_expression.uint_constant);
      break;

   case ast_float_constant:
      type = glsl_type::float_type;
      result = new(ctx) ir_constant(this->primary_expression.float_constant);
      break;

   case ast_bool_constant:
      type = glsl_type::bool_type;
      result = new(ctx) ir_constant(bool(this->primary_expression.bool_constant));
      break;

   case ast_sequence: {
      /* It should not be possible to generate a sequence in the AST without
       * any expressions in it.
       */
      assert(!this->expressions.is_empty());

      /* The r-value of a sequence is the last expression in the sequence.  If
       * the other expressions in the sequence do not have side-effects (and
       * therefore add instructions to the instruction list), they get dropped
       * on the floor.
       */
      foreach_list_typed (ast_node, ast, link, &this->expressions)
	 result = ast->hir(instructions, state);

      type = result->type;

      /* Any errors should have already been emitted in the loop above.
       */
      error_emitted = true;
      break;
   }
   }

   if (type->is_error() && !error_emitted)
      _mesa_glsl_error(& loc, state, "type mismatch");

   return result;
}


ir_rvalue *
ast_expression_statement::hir(exec_list *instructions,
			      struct _mesa_glsl_parse_state *state)
{
   /* It is possible to have expression statements that don't have an
    * expression.  This is the solitary semicolon:
    *
    * for (i = 0; i < 5; i++)
    *     ;
    *
    * In this case the expression will be NULL.  Test for NULL and don't do
    * anything in that case.
    */
   if (expression != NULL)
      expression->hir(instructions, state);

   /* Statements do not have r-values.
    */
   return NULL;
}


ir_rvalue *
ast_compound_statement::hir(exec_list *instructions,
			    struct _mesa_glsl_parse_state *state)
{
   if (new_scope)
      state->symbols->push_scope();

   foreach_list_typed (ast_node, ast, link, &this->statements)
      ast->hir(instructions, state);

   if (new_scope)
      state->symbols->pop_scope();

   /* Compound statements do not have r-values.
    */
   return NULL;
}


static const glsl_type *
process_array_type(const glsl_type *base, ast_node *array_size,
		   struct _mesa_glsl_parse_state *state)
{
   unsigned length = 0;

   /* FINISHME: Reject delcarations of multidimensional arrays. */

   if (array_size != NULL) {
      exec_list dummy_instructions;
      ir_rvalue *const ir = array_size->hir(& dummy_instructions, state);
      YYLTYPE loc = array_size->get_location();

      /* FINISHME: Verify that the grammar forbids side-effects in array
       * FINISHME: sizes.   i.e., 'vec4 [x = 12] data'
       */
      assert(dummy_instructions.is_empty());

      if (ir != NULL) {
	 if (!ir->type->is_integer()) {
	    _mesa_glsl_error(& loc, state, "array size must be integer type");
	 } else if (!ir->type->is_scalar()) {
	    _mesa_glsl_error(& loc, state, "array size must be scalar type");
	 } else {
	    ir_constant *const size = ir->constant_expression_value();

	    if (size == NULL) {
	       _mesa_glsl_error(& loc, state, "array size must be a "
				"constant valued expression");
	    } else if (size->value.i[0] <= 0) {
	       _mesa_glsl_error(& loc, state, "array size must be > 0");
	    } else {
	       assert(size->type == ir->type);
	       length = size->value.u[0];
	    }
	 }
      }
   }

   return glsl_type::get_array_instance(state, base, length);
}


const glsl_type *
ast_type_specifier::glsl_type(const char **name,
			      struct _mesa_glsl_parse_state *state) const
{
   const struct glsl_type *type;

   if ((this->type_specifier == ast_struct) && (this->type_name == NULL)) {
      /* FINISHME: Handle annonymous structures. */
      type = NULL;
   } else {
      type = state->symbols->get_type(this->type_name);
      *name = this->type_name;

      if (this->is_array) {
	 type = process_array_type(type, this->array_size, state);
      }
   }

   return type;
}


static void
apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
				 struct ir_variable *var,
				 struct _mesa_glsl_parse_state *state,
				 YYLTYPE *loc)
{
   if (qual->invariant)
      var->invariant = 1;

   /* FINISHME: Mark 'in' variables at global scope as read-only. */
   if (qual->constant || qual->attribute || qual->uniform
       || (qual->varying && (state->target == fragment_shader)))
      var->read_only = 1;

   if (qual->centroid)
      var->centroid = 1;

   if (qual->attribute && state->target != vertex_shader) {
      var->type = glsl_type::error_type;
      _mesa_glsl_error(loc, state,
		       "`attribute' variables may not be declared in the "
		       "%s shader",
		       _mesa_glsl_shader_target_name(state->target));
   }

   /* From page 25 (page 31 of the PDF) of the GLSL 1.10 spec:
    *
    *     "The varying qualifier can be used only with the data types
    *     float, vec2, vec3, vec4, mat2, mat3, and mat4, or arrays of
    *     these."
    */
   if (qual->varying) {
      const glsl_type *non_array_type;

      if (var->type && var->type->is_array())
	 non_array_type = var->type->fields.array;
      else
	 non_array_type = var->type;

      if (non_array_type && non_array_type->base_type != GLSL_TYPE_FLOAT) {
	 var->type = glsl_type::error_type;
	 _mesa_glsl_error(loc, state,
			  "varying variables must be of base type float");
      }
   }

   if (qual->in && qual->out)
      var->mode = ir_var_inout;
   else if (qual->attribute || qual->in
	    || (qual->varying && (state->target == fragment_shader)))
      var->mode = ir_var_in;
   else if (qual->out || (qual->varying && (state->target == vertex_shader)))
      var->mode = ir_var_out;
   else if (qual->uniform)
      var->mode = ir_var_uniform;
   else
      var->mode = ir_var_auto;

   if (qual->uniform)
      var->shader_in = true;

   /* Any 'in' or 'inout' variables at global scope must be marked as being
    * shader inputs.  Likewise, any 'out' or 'inout' variables at global scope
    * must be marked as being shader outputs.
    */
   if (state->current_function == NULL) {
      switch (var->mode) {
      case ir_var_in:
      case ir_var_uniform:
	 var->shader_in = true;
	 break;
      case ir_var_out:
	 var->shader_out = true;
	 break;
      case ir_var_inout:
	 var->shader_in = true;
	 var->shader_out = true;
	 break;
      default:
	 break;
      }
   }

   if (qual->flat)
      var->interpolation = ir_var_flat;
   else if (qual->noperspective)
      var->interpolation = ir_var_noperspective;
   else
      var->interpolation = ir_var_smooth;

   if (var->type->is_array() && (state->language_version >= 120)) {
      var->array_lvalue = true;
   }
}


ir_rvalue *
ast_declarator_list::hir(exec_list *instructions,
			 struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;
   const struct glsl_type *decl_type;
   const char *type_name = NULL;
   ir_rvalue *result = NULL;
   YYLTYPE loc = this->get_location();

   /* From page 46 (page 52 of the PDF) of the GLSL 1.50 spec:
    *
    *     "To ensure that a particular output variable is invariant, it is
    *     necessary to use the invariant qualifier. It can either be used to
    *     qualify a previously declared variable as being invariant
    *
    *         invariant gl_Position; // make existing gl_Position be invariant"
    *
    * In these cases the parser will set the 'invariant' flag in the declarator
    * list, and the type will be NULL.
    */
   if (this->invariant) {
      assert(this->type == NULL);

      if (state->current_function != NULL) {
	 _mesa_glsl_error(& loc, state,
			  "All uses of `invariant' keyword must be at global "
			  "scope\n");
      }

      foreach_list_typed (ast_declaration, decl, link, &this->declarations) {
	 assert(!decl->is_array);
	 assert(decl->array_size == NULL);
	 assert(decl->initializer == NULL);

	 ir_variable *const earlier =
	    state->symbols->get_variable(decl->identifier);
	 if (earlier == NULL) {
	    _mesa_glsl_error(& loc, state,
			     "Undeclared variable `%s' cannot be marked "
			     "invariant\n", decl->identifier);
	 } else if ((state->target == vertex_shader)
	       && (earlier->mode != ir_var_out)) {
	    _mesa_glsl_error(& loc, state,
			     "`%s' cannot be marked invariant, vertex shader "
			     "outputs only\n", decl->identifier);
	 } else if ((state->target == fragment_shader)
	       && (earlier->mode != ir_var_in)) {
	    _mesa_glsl_error(& loc, state,
			     "`%s' cannot be marked invariant, fragment shader "
			     "inputs only\n", decl->identifier);
	 } else {
	    earlier->invariant = true;
	 }
      }

      /* Invariant redeclarations do not have r-values.
       */
      return NULL;
   }

   assert(this->type != NULL);
   assert(!this->invariant);

   /* The type specifier may contain a structure definition.  Process that
    * before any of the variable declarations.
    */
   (void) this->type->specifier->hir(instructions, state);

   decl_type = this->type->specifier->glsl_type(& type_name, state);
   if (this->declarations.is_empty()) {
      /* The only valid case where the declaration list can be empty is when
       * the declaration is setting the default precision of a built-in type
       * (e.g., 'precision highp vec4;').
       */

      if (decl_type != NULL) {
      } else {
	    _mesa_glsl_error(& loc, state, "incomplete declaration");
      }
   }

   foreach_list_typed (ast_declaration, decl, link, &this->declarations) {
      const struct glsl_type *var_type;
      struct ir_variable *var;

      /* FINISHME: Emit a warning if a variable declaration shadows a
       * FINISHME: declaration at a higher scope.
       */

      if ((decl_type == NULL) || decl_type->is_void()) {
	 if (type_name != NULL) {
	    _mesa_glsl_error(& loc, state,
			     "invalid type `%s' in declaration of `%s'",
			     type_name, decl->identifier);
	 } else {
	    _mesa_glsl_error(& loc, state,
			     "invalid type in declaration of `%s'",
			     decl->identifier);
	 }
	 continue;
      }

      if (decl->is_array) {
	 var_type = process_array_type(decl_type, decl->array_size, state);
      } else {
	 var_type = decl_type;
      }

      var = new(ctx) ir_variable(var_type, decl->identifier);

      /* From page 22 (page 28 of the PDF) of the GLSL 1.10 specification;
       *
       *     "Global variables can only use the qualifiers const,
       *     attribute, uni form, or varying. Only one may be
       *     specified.
       *
       *     Local variables can only use the qualifier const."
       *
       * This is relaxed in GLSL 1.30.
       */
      if (state->language_version < 120) {
	 if (this->type->qualifier.out) {
	    _mesa_glsl_error(& loc, state,
			     "`out' qualifier in declaration of `%s' "
			     "only valid for function parameters in GLSL 1.10.",
			     decl->identifier);
	 }
	 if (this->type->qualifier.in) {
	    _mesa_glsl_error(& loc, state,
			     "`in' qualifier in declaration of `%s' "
			     "only valid for function parameters in GLSL 1.10.",
			     decl->identifier);
	 }
	 /* FINISHME: Test for other invalid qualifiers. */
      }

      apply_type_qualifier_to_variable(& this->type->qualifier, var, state,
				       & loc);

      if (this->type->qualifier.invariant) {
	 if ((state->target == vertex_shader) && !var->shader_out) {
	    _mesa_glsl_error(& loc, state,
			     "`%s' cannot be marked invariant, vertex shader "
			     "outputs only\n", var->name);
	 } else if ((state->target == fragment_shader) && !var->shader_in) {
	    _mesa_glsl_error(& loc, state,
			     "`%s' cannot be marked invariant, fragment shader "
			     "inputs only\n", var->name);
	 }
      }

      if (state->current_function != NULL) {
	 const char *mode = NULL;
	 const char *extra = "";

	 /* There is no need to check for 'inout' here because the parser will
	  * only allow that in function parameter lists.
	  */
	 if (this->type->qualifier.attribute) {
	    mode = "attribute";
	 } else if (this->type->qualifier.uniform) {
	    mode = "uniform";
	 } else if (this->type->qualifier.varying) {
	    mode = "varying";
	 } else if (this->type->qualifier.in) {
	    mode = "in";
	    extra = " or in function parameter list";
	 } else if (this->type->qualifier.out) {
	    mode = "out";
	    extra = " or in function parameter list";
	 }

	 if (mode) {
	    _mesa_glsl_error(& loc, state,
			     "%s variable `%s' must be declared at "
			     "global scope%s",
			     mode, var->name, extra);
	 }
      } else if (var->mode == ir_var_in) {
	 if (state->target == vertex_shader) {
	    bool error_emitted = false;

	    /* From page 31 (page 37 of the PDF) of the GLSL 1.50 spec:
	     *
	     *    "Vertex shader inputs can only be float, floating-point
	     *    vectors, matrices, signed and unsigned integers and integer
	     *    vectors. Vertex shader inputs can also form arrays of these
	     *    types, but not structures."
	     *
	     * From page 31 (page 27 of the PDF) of the GLSL 1.30 spec:
	     *
	     *    "Vertex shader inputs can only be float, floating-point
	     *    vectors, matrices, signed and unsigned integers and integer
	     *    vectors. They cannot be arrays or structures."
	     *
	     * From page 23 (page 29 of the PDF) of the GLSL 1.20 spec:
	     *
	     *    "The attribute qualifier can be used only with float,
	     *    floating-point vectors, and matrices. Attribute variables
	     *    cannot be declared as arrays or structures."
	     */
	    const glsl_type *check_type = var->type->is_array()
	       ? var->type->fields.array : var->type;

	    switch (check_type->base_type) {
	    case GLSL_TYPE_FLOAT:
	       break;
	    case GLSL_TYPE_UINT:
	    case GLSL_TYPE_INT:
	       if (state->language_version > 120)
		  break;
	       /* FALLTHROUGH */
	    default:
	       _mesa_glsl_error(& loc, state,
				"vertex shader input / attribute cannot have "
				"type %s`%s'",
				var->type->is_array() ? "array of " : "",
				check_type->name);
	       error_emitted = true;
	    }

	    if (!error_emitted && (state->language_version <= 130)
		&& var->type->is_array()) {
	       _mesa_glsl_error(& loc, state,
				"vertex shader input / attribute cannot have "
				"array type");
	       error_emitted = true;
	    }
	 }
      }

      instructions->push_tail(var);

      if (decl->initializer != NULL) {
	 YYLTYPE initializer_loc = decl->initializer->get_location();

	 /* From page 24 (page 30 of the PDF) of the GLSL 1.10 spec:
	  *
	  *    "All uniform variables are read-only and are initialized either
	  *    directly by an application via API commands, or indirectly by
	  *    OpenGL."
	  */
	 if ((state->language_version <= 110)
	     && (var->mode == ir_var_uniform)) {
	    _mesa_glsl_error(& initializer_loc, state,
			     "cannot initialize uniforms in GLSL 1.10");
	 }

	 if (var->type->is_sampler()) {
	    _mesa_glsl_error(& initializer_loc, state,
			     "cannot initialize samplers");
	 }

	 if ((var->mode == ir_var_in) && (state->current_function == NULL)) {
	    _mesa_glsl_error(& initializer_loc, state,
			     "cannot initialize %s shader input / %s",
			     _mesa_glsl_shader_target_name(state->target),
			     (state->target == vertex_shader)
			     ? "attribute" : "varying");
	 }

	 ir_dereference *const lhs = new(ctx) ir_dereference_variable(var);
	 ir_rvalue *rhs = decl->initializer->hir(instructions, state);

	 /* Calculate the constant value if this is a const or uniform
	  * declaration.
	  */
	 if (this->type->qualifier.constant || this->type->qualifier.uniform) {
	    ir_constant *constant_value = rhs->constant_expression_value();
	    if (!constant_value) {
	       _mesa_glsl_error(& initializer_loc, state,
				"initializer of %s variable `%s' must be a "
				"constant expression",
				(this->type->qualifier.constant)
				? "const" : "uniform",
				decl->identifier);
	    } else {
	       rhs = constant_value;
	       var->constant_value = constant_value;
	    }
	 }

	 if (rhs && !rhs->type->is_error()) {
	    bool temp = var->read_only;
	    if (this->type->qualifier.constant)
	       var->read_only = false;

	    /* Never emit code to initialize a uniform.
	     */
	    if (!this->type->qualifier.uniform)
	       result = do_assignment(instructions, state, lhs, rhs,
				      this->get_location());
	    var->read_only = temp;
	 }
      }

      /* From page 23 (page 29 of the PDF) of the GLSL 1.10 spec:
       *
       *     "It is an error to write to a const variable outside of
       *      its declaration, so they must be initialized when
       *      declared."
       */
      if (this->type->qualifier.constant && decl->initializer == NULL) {
	 _mesa_glsl_error(& loc, state,
			  "const declaration of `%s' must be initialized");
      }

      /* Attempt to add the variable to the symbol table.  If this fails, it
       * means the variable has already been declared at this scope.  Arrays
       * fudge this rule a little bit.
       *
       * From page 24 (page 30 of the PDF) of the GLSL 1.50 spec,
       *
       *    "It is legal to declare an array without a size and then
       *    later re-declare the same name as an array of the same
       *    type and specify a size."
       */
      if (state->symbols->name_declared_this_scope(decl->identifier)) {
	 ir_variable *const earlier =
	    state->symbols->get_variable(decl->identifier);

	 if ((earlier != NULL)
	     && (earlier->type->array_size() == 0)
	     && var->type->is_array()
	     && (var->type->element_type() == earlier->type->element_type())) {
	    /* FINISHME: This doesn't match the qualifiers on the two
	     * FINISHME: declarations.  It's not 100% clear whether this is
	     * FINISHME: required or not.
	     */

	    /* From page 54 (page 60 of the PDF) of the GLSL 1.20 spec:
	     *
	     *     "The size [of gl_TexCoord] can be at most
	     *     gl_MaxTextureCoords."
	     */
	    const unsigned size = unsigned(var->type->array_size());
	    if ((strcmp("gl_TexCoord", var->name) == 0)
		&& (size > state->Const.MaxTextureCoords)) {
	       YYLTYPE loc = this->get_location();

	       _mesa_glsl_error(& loc, state, "`gl_TexCoord' array size cannot "
				"be larger than gl_MaxTextureCoords (%u)\n",
				state->Const.MaxTextureCoords);
	    } else if ((size > 0) && (size <= earlier->max_array_access)) {
	       YYLTYPE loc = this->get_location();

	       _mesa_glsl_error(& loc, state, "array size must be > %u due to "
				"previous access",
				earlier->max_array_access);
	    }

	    earlier->type = var->type;
	    delete var;
	    var = NULL;
	 } else {
	    YYLTYPE loc = this->get_location();

	    _mesa_glsl_error(& loc, state, "`%s' redeclared",
			     decl->identifier);
	 }

	 continue;
      }

      /* From page 15 (page 21 of the PDF) of the GLSL 1.10 spec,
       *
       *   "Identifiers starting with "gl_" are reserved for use by
       *   OpenGL, and may not be declared in a shader as either a
       *   variable or a function."
       */
      if (strncmp(decl->identifier, "gl_", 3) == 0) {
	 /* FINISHME: This should only trigger if we're not redefining
	  * FINISHME: a builtin (to add a qualifier, for example).
	  */
	 _mesa_glsl_error(& loc, state,
			  "identifier `%s' uses reserved `gl_' prefix",
			  decl->identifier);
      }

      /* Add the variable to the symbol table after processing the initializer.
       * This differs from most C-like languages, but it follows the GLSL
       * specification.  From page 28 (page 34 of the PDF) of the GLSL 1.50
       * spec:
       *
       *     "Within a declaration, the scope of a name starts immediately
       *     after the initializer if present or immediately after the name
       *     being declared if not."
       */
      const bool added_variable =
	 state->symbols->add_variable(var->name, var);
      assert(added_variable);
   }


   /* Generally, variable declarations do not have r-values.  However,
    * one is used for the declaration in
    *
    * while (bool b = some_condition()) {
    *   ...
    * }
    *
    * so we return the rvalue from the last seen declaration here.
    */
   return result;
}


ir_rvalue *
ast_parameter_declarator::hir(exec_list *instructions,
			      struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;
   const struct glsl_type *type;
   const char *name = NULL;
   YYLTYPE loc = this->get_location();

   type = this->type->specifier->glsl_type(& name, state);

   if (type == NULL) {
      if (name != NULL) {
	 _mesa_glsl_error(& loc, state,
			  "invalid type `%s' in declaration of `%s'",
			  name, this->identifier);
      } else {
	 _mesa_glsl_error(& loc, state,
			  "invalid type in declaration of `%s'",
			  this->identifier);
      }

      type = glsl_type::error_type;
   }

   /* From page 62 (page 68 of the PDF) of the GLSL 1.50 spec:
    *
    *    "Functions that accept no input arguments need not use void in the
    *    argument list because prototypes (or definitions) are required and
    *    therefore there is no ambiguity when an empty argument list "( )" is
    *    declared. The idiom "(void)" as a parameter list is provided for
    *    convenience."
    *
    * Placing this check here prevents a void parameter being set up
    * for a function, which avoids tripping up checks for main taking
    * parameters and lookups of an unnamed symbol.
    */
   if (type->is_void()) {
      if (this->identifier != NULL)
	 _mesa_glsl_error(& loc, state,
			  "named parameter cannot have type `void'");

      is_void = true;
      return NULL;
   }

   if (formal_parameter && (this->identifier == NULL)) {
      _mesa_glsl_error(& loc, state, "formal parameter lacks a name");
      return NULL;
   }

   is_void = false;
   ir_variable *var = new(ctx) ir_variable(type, this->identifier);

   /* FINISHME: Handle array declarations.  Note that this requires
    * FINISHME: complete handling of constant expressions.
    */

   /* Apply any specified qualifiers to the parameter declaration.  Note that
    * for function parameters the default mode is 'in'.
    */
   apply_type_qualifier_to_variable(& this->type->qualifier, var, state, & loc);
   if (var->mode == ir_var_auto)
      var->mode = ir_var_in;

   instructions->push_tail(var);

   /* Parameter declarations do not have r-values.
    */
   return NULL;
}


void
ast_parameter_declarator::parameters_to_hir(exec_list *ast_parameters,
					    bool formal,
					    exec_list *ir_parameters,
					    _mesa_glsl_parse_state *state)
{
   ast_parameter_declarator *void_param = NULL;
   unsigned count = 0;

   foreach_list_typed (ast_parameter_declarator, param, link, ast_parameters) {
      param->formal_parameter = formal;
      param->hir(ir_parameters, state);

      if (param->is_void)
	 void_param = param;

      count++;
   }

   if ((void_param != NULL) && (count > 1)) {
      YYLTYPE loc = void_param->get_location();

      _mesa_glsl_error(& loc, state,
		       "`void' parameter must be only parameter");
   }
}


ir_rvalue *
ast_function::hir(exec_list *instructions,
		  struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;
   ir_function *f = NULL;
   ir_function_signature *sig = NULL;
   exec_list hir_parameters;

   const char *const name = identifier;

   /* Convert the list of function parameters to HIR now so that they can be
    * used below to compare this function's signature with previously seen
    * signatures for functions with the same name.
    */
   ast_parameter_declarator::parameters_to_hir(& this->parameters,
					       is_definition,
					       & hir_parameters, state);

   const char *return_type_name;
   const glsl_type *return_type =
      this->return_type->specifier->glsl_type(& return_type_name, state);

   assert(return_type != NULL);

   /* From page 56 (page 62 of the PDF) of the GLSL 1.30 spec:
    * "No qualifier is allowed on the return type of a function."
    */
   if (this->return_type->has_qualifiers()) {
      YYLTYPE loc = this->get_location();
      _mesa_glsl_error(& loc, state,
		       "function `%s' return type has qualifiers", name);
   }

   /* Verify that this function's signature either doesn't match a previously
    * seen signature for a function with the same name, or, if a match is found,
    * that the previously seen signature does not have an associated definition.
    */
   f = state->symbols->get_function(name);
   if (f != NULL) {
      ir_function_signature *sig = f->exact_matching_signature(&hir_parameters);
      if (sig != NULL) {
	 const char *badvar = sig->qualifiers_match(&hir_parameters);
	 if (badvar != NULL) {
	    YYLTYPE loc = this->get_location();

	    _mesa_glsl_error(&loc, state, "function `%s' parameter `%s' "
			     "qualifiers don't match prototype", name, badvar);
	 }

	 if (sig->return_type != return_type) {
	    YYLTYPE loc = this->get_location();

	    _mesa_glsl_error(&loc, state, "function `%s' return type doesn't "
			     "match prototype", name);
	 }

	 if (is_definition && sig->is_defined) {
	    YYLTYPE loc = this->get_location();

	    _mesa_glsl_error(& loc, state, "function `%s' redefined", name);
	    sig = NULL;
	 }
      }
   } else if (state->symbols->name_declared_this_scope(name)) {
      /* This function name shadows a non-function use of the same name.
       */
      YYLTYPE loc = this->get_location();

      _mesa_glsl_error(& loc, state, "function name `%s' conflicts with "
		       "non-function", name);
      sig = NULL;
   } else {
      f = new(ctx) ir_function(name);
      state->symbols->add_function(f->name, f);

      /* Emit the new function header */
      instructions->push_tail(f);
   }

   /* Verify the return type of main() */
   if (strcmp(name, "main") == 0) {
      if (! return_type->is_void()) {
	 YYLTYPE loc = this->get_location();

	 _mesa_glsl_error(& loc, state, "main() must return void");
      }

      if (!hir_parameters.is_empty()) {
	 YYLTYPE loc = this->get_location();

	 _mesa_glsl_error(& loc, state, "main() must not take any parameters");
      }
   }

   /* Finish storing the information about this new function in its signature.
    */
   if (sig == NULL) {
      sig = new(ctx) ir_function_signature(return_type);
      f->add_signature(sig);
   }

   sig->replace_parameters(&hir_parameters);
   signature = sig;

   /* Function declarations (prototypes) do not have r-values.
    */
   return NULL;
}


ir_rvalue *
ast_function_definition::hir(exec_list *instructions,
			     struct _mesa_glsl_parse_state *state)
{
   prototype->is_definition = true;
   prototype->hir(instructions, state);

   ir_function_signature *signature = prototype->signature;

   assert(state->current_function == NULL);
   state->current_function = signature;
   state->found_return = false;

   /* Duplicate parameters declared in the prototype as concrete variables.
    * Add these to the symbol table.
    */
   state->symbols->push_scope();
   foreach_iter(exec_list_iterator, iter, signature->parameters) {
      ir_variable *const var = ((ir_instruction *) iter.get())->as_variable();

      assert(var != NULL);

      /* The only way a parameter would "exist" is if two parameters have
       * the same name.
       */
      if (state->symbols->name_declared_this_scope(var->name)) {
	 YYLTYPE loc = this->get_location();

	 _mesa_glsl_error(& loc, state, "parameter `%s' redeclared", var->name);
      } else {
	 state->symbols->add_variable(var->name, var);
      }
   }

   /* Convert the body of the function to HIR. */
   this->body->hir(&signature->body, state);
   signature->is_defined = true;

   state->symbols->pop_scope();

   assert(state->current_function == signature);
   state->current_function = NULL;

   if (!signature->return_type->is_void() && !state->found_return) {
      YYLTYPE loc = this->get_location();
      _mesa_glsl_error(& loc, state, "function `%s' has non-void return type "
		       "%s, but no return statement",
		       signature->function_name(),
		       signature->return_type->name);
   }

   /* Function definitions do not have r-values.
    */
   return NULL;
}


ir_rvalue *
ast_jump_statement::hir(exec_list *instructions,
			struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;

   switch (mode) {
   case ast_return: {
      ir_return *inst;
      assert(state->current_function);

      if (opt_return_value) {
	 if (state->current_function->return_type->base_type ==
	     GLSL_TYPE_VOID) {
	    YYLTYPE loc = this->get_location();

	    _mesa_glsl_error(& loc, state,
			     "`return` with a value, in function `%s' "
			     "returning void",
			     state->current_function->function_name());
	 }

	 ir_expression *const ret = (ir_expression *)
	    opt_return_value->hir(instructions, state);
	 assert(ret != NULL);

	 /* Implicit conversions are not allowed for return values. */
	 if (state->current_function->return_type != ret->type) {
	    YYLTYPE loc = this->get_location();

	    _mesa_glsl_error(& loc, state,
			     "`return' with wrong type %s, in function `%s' "
			     "returning %s",
			     ret->type->name,
			     state->current_function->function_name(),
			     state->current_function->return_type->name);
	 }

	 inst = new(ctx) ir_return(ret);
      } else {
	 if (state->current_function->return_type->base_type !=
	     GLSL_TYPE_VOID) {
	    YYLTYPE loc = this->get_location();

	    _mesa_glsl_error(& loc, state,
			     "`return' with no value, in function %s returning "
			     "non-void",
			     state->current_function->function_name());
	 }
	 inst = new(ctx) ir_return;
      }

      state->found_return = true;
      instructions->push_tail(inst);
      break;
   }

   case ast_discard:
      if (state->target != fragment_shader) {
	 YYLTYPE loc = this->get_location();

	 _mesa_glsl_error(& loc, state,
			  "`discard' may only appear in a fragment shader");
      }
      instructions->push_tail(new(ctx) ir_discard);
      break;

   case ast_break:
   case ast_continue:
      /* FINISHME: Handle switch-statements.  They cannot contain 'continue',
       * FINISHME: and they use a different IR instruction for 'break'.
       */
      /* FINISHME: Correctly handle the nesting.  If a switch-statement is
       * FINISHME: inside a loop, a 'continue' is valid and will bind to the
       * FINISHME: loop.
       */
      if (state->loop_or_switch_nesting == NULL) {
	 YYLTYPE loc = this->get_location();

	 _mesa_glsl_error(& loc, state,
			  "`%s' may only appear in a loop",
			  (mode == ast_break) ? "break" : "continue");
      } else {
	 ir_loop *const loop = state->loop_or_switch_nesting->as_loop();

	 if (loop != NULL) {
	    ir_loop_jump *const jump =
	       new(ctx) ir_loop_jump((mode == ast_break)
				     ? ir_loop_jump::jump_break
				     : ir_loop_jump::jump_continue);
	    instructions->push_tail(jump);
	 }
      }

      break;
   }

   /* Jump instructions do not have r-values.
    */
   return NULL;
}


ir_rvalue *
ast_selection_statement::hir(exec_list *instructions,
			     struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;

   ir_rvalue *const condition = this->condition->hir(instructions, state);

   /* From page 66 (page 72 of the PDF) of the GLSL 1.50 spec:
    *
    *    "Any expression whose type evaluates to a Boolean can be used as the
    *    conditional expression bool-expression. Vector types are not accepted
    *    as the expression to if."
    *
    * The checks are separated so that higher quality diagnostics can be
    * generated for cases where both rules are violated.
    */
   if (!condition->type->is_boolean() || !condition->type->is_scalar()) {
      YYLTYPE loc = this->condition->get_location();

      _mesa_glsl_error(& loc, state, "if-statement condition must be scalar "
		       "boolean");
   }

   ir_if *const stmt = new(ctx) ir_if(condition);

   if (then_statement != NULL)
      then_statement->hir(& stmt->then_instructions, state);

   if (else_statement != NULL)
      else_statement->hir(& stmt->else_instructions, state);

   instructions->push_tail(stmt);

   /* if-statements do not have r-values.
    */
   return NULL;
}


void
ast_iteration_statement::condition_to_hir(ir_loop *stmt,
					  struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;

   if (condition != NULL) {
      ir_rvalue *const cond =
	 condition->hir(& stmt->body_instructions, state);

      if ((cond == NULL)
	  || !cond->type->is_boolean() || !cond->type->is_scalar()) {
	 YYLTYPE loc = condition->get_location();

	 _mesa_glsl_error(& loc, state,
			  "loop condition must be scalar boolean");
      } else {
	 /* As the first code in the loop body, generate a block that looks
	  * like 'if (!condition) break;' as the loop termination condition.
	  */
	 ir_rvalue *const not_cond =
	    new(ctx) ir_expression(ir_unop_logic_not, glsl_type::bool_type, cond,
				   NULL);

	 ir_if *const if_stmt = new(ctx) ir_if(not_cond);

	 ir_jump *const break_stmt =
	    new(ctx) ir_loop_jump(ir_loop_jump::jump_break);

	 if_stmt->then_instructions.push_tail(break_stmt);
	 stmt->body_instructions.push_tail(if_stmt);
      }
   }
}


ir_rvalue *
ast_iteration_statement::hir(exec_list *instructions,
			     struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;

   /* For-loops and while-loops start a new scope, but do-while loops do not.
    */
   if (mode != ast_do_while)
      state->symbols->push_scope();

   if (init_statement != NULL)
      init_statement->hir(instructions, state);

   ir_loop *const stmt = new(ctx) ir_loop();
   instructions->push_tail(stmt);

   /* Track the current loop and / or switch-statement nesting.
    */
   ir_instruction *const nesting = state->loop_or_switch_nesting;
   state->loop_or_switch_nesting = stmt;

   if (mode != ast_do_while)
      condition_to_hir(stmt, state);

   if (body != NULL)
      body->hir(& stmt->body_instructions, state);

   if (rest_expression != NULL)
      rest_expression->hir(& stmt->body_instructions, state);

   if (mode == ast_do_while)
      condition_to_hir(stmt, state);

   if (mode != ast_do_while)
      state->symbols->pop_scope();

   /* Restore previous nesting before returning.
    */
   state->loop_or_switch_nesting = nesting;

   /* Loops do not have r-values.
    */
   return NULL;
}


ir_rvalue *
ast_type_specifier::hir(exec_list *instructions,
			  struct _mesa_glsl_parse_state *state)
{
   if (this->structure != NULL)
      return this->structure->hir(instructions, state);

   return NULL;
}


ir_rvalue *
ast_struct_specifier::hir(exec_list *instructions,
			  struct _mesa_glsl_parse_state *state)
{
   unsigned decl_count = 0;

   /* Make an initial pass over the list of structure fields to determine how
    * many there are.  Each element in this list is an ast_declarator_list.
    * This means that we actually need to count the number of elements in the
    * 'declarations' list in each of the elements.
    */
   foreach_list_typed (ast_declarator_list, decl_list, link,
		       &this->declarations) {
      foreach_list_const (decl_ptr, & decl_list->declarations) {
	 decl_count++;
      }
   }


   /* Allocate storage for the structure fields and process the field
    * declarations.  As the declarations are processed, try to also convert
    * the types to HIR.  This ensures that structure definitions embedded in
    * other structure definitions are processed.
    */
   glsl_struct_field *const fields = (glsl_struct_field *)
      malloc(sizeof(*fields) * decl_count);

   unsigned i = 0;
   foreach_list_typed (ast_declarator_list, decl_list, link,
		       &this->declarations) {
      const char *type_name;

      decl_list->type->specifier->hir(instructions, state);

      const glsl_type *decl_type =
	 decl_list->type->specifier->glsl_type(& type_name, state);

      foreach_list_typed (ast_declaration, decl, link,
			  &decl_list->declarations) {
	 const struct glsl_type *const field_type =
	    (decl->is_array)
	    ? process_array_type(decl_type, decl->array_size, state)
	    : decl_type;

	 fields[i].type = (field_type != NULL)
	    ? field_type : glsl_type::error_type;
	 fields[i].name = decl->identifier;
	 i++;
      }
   }

   assert(i == decl_count);

   const char *name;
   if (this->name == NULL) {
      static unsigned anon_count = 1;
      char buf[32];

      snprintf(buf, sizeof(buf), "#anon_struct_%04x", anon_count);
      anon_count++;

      name = strdup(buf);
   } else {
      name = this->name;
   }

   const glsl_type *t =
      glsl_type::get_record_instance(fields, decl_count, name);

   YYLTYPE loc = this->get_location();
   if (!state->symbols->add_type(name, t)) {
      _mesa_glsl_error(& loc, state, "struct `%s' previously defined", name);
   } else {
      /* This logic is a bit tricky.  It is an error to declare a structure at
       * global scope if there is also a function with the same name.
       */
      if ((state->current_function == NULL)
	  && (state->symbols->get_function(name) != NULL)) {
	 _mesa_glsl_error(& loc, state, "name `%s' previously defined", name);
      } else {
	 t->generate_constructor(state->symbols);
      }

      const glsl_type **s = (const glsl_type **)
	 realloc(state->user_structures,
		 sizeof(state->user_structures[0]) *
		 (state->num_user_structures + 1));
      if (s != NULL) {
	 s[state->num_user_structures] = t;
	 state->user_structures = s;
	 state->num_user_structures++;
      }
   }

   /* Structure type definitions do not have r-values.
    */
   return NULL;
}