aboutsummaryrefslogtreecommitdiff
path: root/mesalib/src/glsl/ast_to_hir.cpp
blob: 43cf49745573a772d5d56d26ac6ac7b93fbf81a1 (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
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
/*
 * 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/core.h" /* for struct gl_extensions */
#include "glsl_symbol_table.h"
#include "glsl_parser_extras.h"
#include "ast.h"
#include "glsl_types.h"
#include "program/hash_table.h"
#include "ir.h"

static void
detect_conflicting_assignments(struct _mesa_glsl_parse_state *state,
			       exec_list *instructions);
static void
remove_per_vertex_blocks(exec_list *instructions,
                         _mesa_glsl_parse_state *state, ir_variable_mode mode);


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

   state->symbols->separate_function_namespace = state->language_version == 110;

   state->current_function = NULL;

   state->toplevel_ir = instructions;

   state->gs_input_prim_type_specified = false;

   /* Section 4.2 of the GLSL 1.20 specification states:
    * "The built-in functions are scoped in a scope outside the global scope
    *  users declare global variables in.  That is, a shader's global scope,
    *  available for user-defined functions and global variables, is nested
    *  inside the scope containing the built-in functions."
    *
    * Since built-in functions like ftransform() access built-in variables,
    * it follows that those must be in the outer scope as well.
    *
    * We push scope here to create this nesting effect...but don't pop.
    * This way, a shader's globals are still in the symbol table for use
    * by the linker.
    */
   state->symbols->push_scope();

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

   detect_recursion_unlinked(state, instructions);
   detect_conflicting_assignments(state, instructions);

   state->toplevel_ir = NULL;

   /* Move all of the variable declarations to the front of the IR list, and
    * reverse the order.  This has the (intended!) side effect that vertex
    * shader inputs and fragment shader outputs will appear in the IR in the
    * same order that they appeared in the shader code.  This results in the
    * locations being assigned in the declared order.  Many (arguably buggy)
    * applications depend on this behavior, and it matches what nearly all
    * other drivers do.
    */
   foreach_list_safe(node, instructions) {
      ir_variable *const var = ((ir_instruction *) node)->as_variable();

      if (var == NULL)
         continue;

      var->remove();
      instructions->push_head(var);
   }

   /* From section 7.1 (Built-In Language Variables) of the GLSL 4.10 spec:
    *
    *     If multiple shaders using members of a built-in block belonging to
    *     the same interface are linked together in the same program, they
    *     must all redeclare the built-in block in the same way, as described
    *     in section 4.3.7 "Interface Blocks" for interface block matching, or
    *     a link error will result.
    *
    * The phrase "using members of a built-in block" implies that if two
    * shaders are linked together and one of them *does not use* any members
    * of the built-in block, then that shader does not need to have a matching
    * redeclaration of the built-in block.
    *
    * This appears to be a clarification to the behaviour established for
    * gl_PerVertex by GLSL 1.50, therefore implement it regardless of GLSL
    * version.
    *
    * The definition of "interface" in section 4.3.7 that applies here is as
    * follows:
    *
    *     The boundary between adjacent programmable pipeline stages: This
    *     spans all the outputs in all compilation units of the first stage
    *     and all the inputs in all compilation units of the second stage.
    *
    * Therefore this rule applies to both inter- and intra-stage linking.
    *
    * The easiest way to implement this is to check whether the shader uses
    * gl_PerVertex right after ast-to-ir conversion, and if it doesn't, simply
    * remove all the relevant variable declaration from the IR, so that the
    * linker won't see them and complain about mismatches.
    */
   remove_per_vertex_blocks(instructions, state, ir_var_shader_in);
   remove_per_vertex_blocks(instructions, state, ir_var_shader_out);
}


/**
 * 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.
 */
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->is_version(120, 0))
      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) {
	    /* The resulting vector has a number of elements equal to
	     * the number of rows of matrix A. */
	    const glsl_type *const type =
	       glsl_type::get_instance(type_a->base_type,
				       type_a->column_type()->vector_elements,
				       1);
	    assert(type != glsl_type::error_type);

	    return type;
	 }
      } 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()) {
	    /* The resulting vector has a number of elements equal to
	     * the number of columns of matrix B. */
	    const glsl_type *const type =
	       glsl_type::get_instance(type_a->base_type,
				       type_b->row_type()->vector_elements,
				       1);
	    assert(type != glsl_type::error_type);

	    return type;
	 }
      }

      _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;
}

/**
 * \brief Return the result type of a bit-logic operation.
 *
 * If the given types to the bit-logic operator are invalid, return
 * glsl_type::error_type.
 *
 * \param type_a Type of LHS of bit-logic op
 * \param type_b Type of RHS of bit-logic op
 */
static const struct glsl_type *
bit_logic_result_type(const struct glsl_type *type_a,
                      const struct glsl_type *type_b,
                      ast_operators op,
                      struct _mesa_glsl_parse_state *state, YYLTYPE *loc)
{
    if (!state->check_bitwise_operations_allowed(loc)) {
       return glsl_type::error_type;
    }

    /* From page 50 (page 56 of PDF) of GLSL 1.30 spec:
     *
     *     "The bitwise operators and (&), exclusive-or (^), and inclusive-or
     *     (|). The operands must be of type signed or unsigned integers or
     *     integer vectors."
     */
    if (!type_a->is_integer()) {
       _mesa_glsl_error(loc, state, "LHS of `%s' must be an integer",
                         ast_expression::operator_string(op));
       return glsl_type::error_type;
    }
    if (!type_b->is_integer()) {
       _mesa_glsl_error(loc, state, "RHS of `%s' must be an integer",
                        ast_expression::operator_string(op));
       return glsl_type::error_type;
    }

    /*     "The fundamental types of the operands (signed or unsigned) must
     *     match,"
     */
    if (type_a->base_type != type_b->base_type) {
       _mesa_glsl_error(loc, state, "operands of `%s' must have the same "
                        "base type", ast_expression::operator_string(op));
       return glsl_type::error_type;
    }

    /*     "The operands cannot be vectors of differing size." */
    if (type_a->is_vector() &&
        type_b->is_vector() &&
        type_a->vector_elements != type_b->vector_elements) {
       _mesa_glsl_error(loc, state, "operands of `%s' cannot be vectors of "
                        "different sizes", ast_expression::operator_string(op));
       return glsl_type::error_type;
    }

    /*     "If one operand is a scalar and the other a vector, the scalar is
     *     applied component-wise to the vector, resulting in the same type as
     *     the vector. The fundamental types of the operands [...] will be the
     *     resulting fundamental type."
     */
    if (type_a->is_scalar())
        return type_b;
    else
        return type_a;
}

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)
{
   if (!state->check_version(130, 300, loc, "operator '%%' is reserved")) {
      return glsl_type::error_type;
   }

   /* 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()) {
      _mesa_glsl_error(loc, state, "LHS of operator %% must be an integer");
      return glsl_type::error_type;
   }
   if (!type_b->is_integer()) {
      _mesa_glsl_error(loc, state, "RHS of operator %% must be an integer");
      return glsl_type::error_type;
   }
   if (type_a->base_type != type_b->base_type) {
      _mesa_glsl_error(loc, state,
		       "operands of %% must have the same base type");
      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;
}

/**
 * \brief Return the result type of a bit-shift operation.
 *
 * If the given types to the bit-shift operator are invalid, return
 * glsl_type::error_type.
 *
 * \param type_a Type of LHS of bit-shift op
 * \param type_b Type of RHS of bit-shift op
 */
static const struct glsl_type *
shift_result_type(const struct glsl_type *type_a,
                  const struct glsl_type *type_b,
                  ast_operators op,
                  struct _mesa_glsl_parse_state *state, YYLTYPE *loc)
{
   if (!state->check_bitwise_operations_allowed(loc)) {
      return glsl_type::error_type;
   }

   /* From page 50 (page 56 of the PDF) of the GLSL 1.30 spec:
    *
    *     "The shift operators (<<) and (>>). For both operators, the operands
    *     must be signed or unsigned integers or integer vectors. One operand
    *     can be signed while the other is unsigned."
    */
   if (!type_a->is_integer()) {
      _mesa_glsl_error(loc, state, "LHS of operator %s must be an integer or "
              "integer vector", ast_expression::operator_string(op));
     return glsl_type::error_type;

   }
   if (!type_b->is_integer()) {
      _mesa_glsl_error(loc, state, "RHS of operator %s must be an integer or "
              "integer vector", ast_expression::operator_string(op));
     return glsl_type::error_type;
   }

   /*     "If the first operand is a scalar, the second operand has to be
    *     a scalar as well."
    */
   if (type_a->is_scalar() && !type_b->is_scalar()) {
      _mesa_glsl_error(loc, state, "if the first operand of %s is scalar, the "
              "second must be scalar as well",
              ast_expression::operator_string(op));
     return glsl_type::error_type;
   }

   /* If both operands are vectors, check that they have same number of
    * elements.
    */
   if (type_a->is_vector() &&
      type_b->is_vector() &&
      type_a->vector_elements != type_b->vector_elements) {
      _mesa_glsl_error(loc, state, "vector operands to operator %s must "
              "have same number of elements",
              ast_expression::operator_string(op));
     return glsl_type::error_type;
   }

   /*     "In all cases, the resulting type will be the same type as the left
    *     operand."
    */
   return type_a;
}

/**
 * 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,
                    YYLTYPE loc, const glsl_type *lhs_type,
                    ir_rvalue *rhs, bool is_initializer)
{
   /* 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 LHS is unsized,
    * the assignment is okay for initializers embedded in variable
    * declarations.
    *
    * Note: Whole-array assignments are not permitted in GLSL 1.10, but this
    * is handled by ir_dereference::is_lvalue.
    */
   if (lhs_type->is_unsized_array() && rhs->type->is_array()
       && (lhs_type->element_type() == rhs->type->element_type())) {
      if (is_initializer) {
         return rhs;
      } else {
         _mesa_glsl_error(&loc, state,
                          "implicitly sized arrays cannot be assigned");
         return NULL;
      }
   }

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

   _mesa_glsl_error(&loc, state,
                    "%s of type %s cannot be assigned to "
                    "variable of type %s",
                    is_initializer ? "initializer" : "value",
                    rhs->type->name, lhs_type->name);

   return NULL;
}

static void
mark_whole_array_access(ir_rvalue *access)
{
   ir_dereference_variable *deref = access->as_dereference_variable();

   if (deref && deref->var) {
      deref->var->max_array_access = deref->type->length - 1;
   }
}

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

   /* If the assignment LHS comes back as an ir_binop_vector_extract
    * expression, move it to the RHS as an ir_triop_vector_insert.
    */
   if (lhs->ir_type == ir_type_expression) {
      ir_expression *const expr = lhs->as_expression();

      if (unlikely(expr->operation == ir_binop_vector_extract)) {
         ir_rvalue *new_rhs =
            validate_assignment(state, lhs_loc, lhs->type,
                                rhs, is_initializer);

         if (new_rhs == NULL) {
            return lhs;
         } else {
            rhs = new(ctx) ir_expression(ir_triop_vector_insert,
                                         expr->operands[0]->type,
                                         expr->operands[0],
                                         new_rhs,
                                         expr->operands[1]);
            lhs = expr->operands[0]->clone(ctx, NULL);
         }
      }
   }

   ir_variable *lhs_var = lhs->variable_referenced();
   if (lhs_var)
      lhs_var->assigned = true;

   if (!error_emitted) {
      if (non_lvalue_description != NULL) {
         _mesa_glsl_error(&lhs_loc, state,
                          "assignment to %s",
			  non_lvalue_description);
	 error_emitted = true;
      } else if (lhs->variable_referenced() != NULL
		 && lhs->variable_referenced()->read_only) {
         _mesa_glsl_error(&lhs_loc, state,
                          "assignment to read-only variable '%s'",
                          lhs->variable_referenced()->name);
         error_emitted = true;

      } else if (lhs->type->is_array() &&
                 !state->check_version(120, 300, &lhs_loc,
                                       "whole array assignment forbidden")) {
	 /* From page 32 (page 38 of the PDF) of the GLSL 1.10 spec:
	  *
	  *    "Other binary or unary expressions, non-dereferenced
	  *     arrays, function names, swizzles with repeated fields,
	  *     and constants cannot be l-values."
          *
          * The restriction on arrays is lifted in GLSL 1.20 and GLSL ES 3.00.
	  */
	 error_emitted = true;
      } else 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_loc, lhs->type, rhs, is_initializer);
   if (new_rhs != NULL) {
      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->is_unsized_array()) {
	 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(lhs->type->element_type(),
						   rhs->type->array_size());
	 d->type = var->type;
      }
      mark_whole_array_access(rhs);
      mark_whole_array_access(lhs);
   }

   /* 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_var_temporary);
   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));
   deref_var = new(ctx) ir_dereference_variable(var);

   if (!error_emitted)
      instructions->push_tail(new(ctx) ir_assignment(lhs, deref_var));

   return new(ctx) ir_dereference_variable(var);
}

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

   var = new(ctx) ir_variable(lvalue->type, "_post_incdec_tmp",
			      ir_var_temporary);
   instructions->push_tail(var);
   var->mode = ir_var_auto;

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

   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;
}

static ir_rvalue *
do_comparison(void *mem_ctx, int operation, ir_rvalue *op0, ir_rvalue *op1)
{
   int join_op;
   ir_rvalue *cmp = NULL;

   if (operation == ir_binop_all_equal)
      join_op = ir_binop_logic_and;
   else
      join_op = ir_binop_logic_or;

   switch (op0->type->base_type) {
   case GLSL_TYPE_FLOAT:
   case GLSL_TYPE_UINT:
   case GLSL_TYPE_INT:
   case GLSL_TYPE_BOOL:
      return new(mem_ctx) ir_expression(operation, op0, op1);

   case GLSL_TYPE_ARRAY: {
      for (unsigned int i = 0; i < op0->type->length; i++) {
	 ir_rvalue *e0, *e1, *result;

	 e0 = new(mem_ctx) ir_dereference_array(op0->clone(mem_ctx, NULL),
						new(mem_ctx) ir_constant(i));
	 e1 = new(mem_ctx) ir_dereference_array(op1->clone(mem_ctx, NULL),
						new(mem_ctx) ir_constant(i));
	 result = do_comparison(mem_ctx, operation, e0, e1);

	 if (cmp) {
	    cmp = new(mem_ctx) ir_expression(join_op, cmp, result);
	 } else {
	    cmp = result;
	 }
      }

      mark_whole_array_access(op0);
      mark_whole_array_access(op1);
      break;
   }

   case GLSL_TYPE_STRUCT: {
      for (unsigned int i = 0; i < op0->type->length; i++) {
	 ir_rvalue *e0, *e1, *result;
	 const char *field_name = op0->type->fields.structure[i].name;

	 e0 = new(mem_ctx) ir_dereference_record(op0->clone(mem_ctx, NULL),
						 field_name);
	 e1 = new(mem_ctx) ir_dereference_record(op1->clone(mem_ctx, NULL),
						 field_name);
	 result = do_comparison(mem_ctx, operation, e0, e1);

	 if (cmp) {
	    cmp = new(mem_ctx) ir_expression(join_op, cmp, result);
	 } else {
	    cmp = result;
	 }
      }
      break;
   }

   case GLSL_TYPE_ERROR:
   case GLSL_TYPE_VOID:
   case GLSL_TYPE_SAMPLER:
   case GLSL_TYPE_INTERFACE:
   case GLSL_TYPE_ATOMIC_UINT:
      /* I assume a comparison of a struct containing a sampler just
       * ignores the sampler present in the type.
       */
      break;
   }

   if (cmp == NULL)
      cmp = new(mem_ctx) ir_constant(true);

   return cmp;
}

/* For logical operations, we want to ensure that the operands are
 * scalar booleans.  If it isn't, emit an error and return a constant
 * boolean to avoid triggering cascading error messages.
 */
ir_rvalue *
get_scalar_boolean_operand(exec_list *instructions,
			   struct _mesa_glsl_parse_state *state,
			   ast_expression *parent_expr,
			   int operand,
			   const char *operand_name,
			   bool *error_emitted)
{
   ast_expression *expr = parent_expr->subexpressions[operand];
   void *ctx = state;
   ir_rvalue *val = expr->hir(instructions, state);

   if (val->type->is_boolean() && val->type->is_scalar())
      return val;

   if (!*error_emitted) {
      YYLTYPE loc = expr->get_location();
      _mesa_glsl_error(&loc, state, "%s of `%s' must be scalar boolean",
		       operand_name,
		       parent_expr->operator_string(parent_expr->oper));
      *error_emitted = true;
   }

   return new(ctx) ir_constant(true);
}

/**
 * If name refers to a builtin array whose maximum allowed size is less than
 * size, report an error and return true.  Otherwise return false.
 */
void
check_builtin_array_max_size(const char *name, unsigned size,
                             YYLTYPE loc, struct _mesa_glsl_parse_state *state)
{
   if ((strcmp("gl_TexCoord", name) == 0)
       && (size > state->Const.MaxTextureCoords)) {
      /* 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."
       */
      _mesa_glsl_error(&loc, state, "`gl_TexCoord' array size cannot "
                       "be larger than gl_MaxTextureCoords (%u)",
                       state->Const.MaxTextureCoords);
   } else if (strcmp("gl_ClipDistance", name) == 0
              && size > state->Const.MaxClipPlanes) {
      /* From section 7.1 (Vertex Shader Special Variables) of the
       * GLSL 1.30 spec:
       *
       *   "The gl_ClipDistance array is predeclared as unsized and
       *   must be sized by the shader either redeclaring it with a
       *   size or indexing it only with integral constant
       *   expressions. ... The size can be at most
       *   gl_MaxClipDistances."
       */
      _mesa_glsl_error(&loc, state, "`gl_ClipDistance' array size cannot "
                       "be larger than gl_MaxClipDistances (%u)",
                       state->Const.MaxClipPlanes);
   }
}

/**
 * Create the constant 1, of a which is appropriate for incrementing and
 * decrementing values of the given GLSL type.  For example, if type is vec4,
 * this creates a constant value of 1.0 having type float.
 *
 * If the given type is invalid for increment and decrement operators, return
 * a floating point 1--the error will be detected later.
 */
static ir_rvalue *
constant_one_for_inc_dec(void *ctx, const glsl_type *type)
{
   switch (type->base_type) {
   case GLSL_TYPE_UINT:
      return new(ctx) ir_constant((unsigned) 1);
   case GLSL_TYPE_INT:
      return new(ctx) ir_constant(1);
   default:
   case GLSL_TYPE_FLOAT:
      return new(ctx) ir_constant(1.0f);
   }
}

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_all_equal,
      ir_binop_any_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[3];
   const struct glsl_type *type; /* a temporary variable for switch cases */
   bool error_emitted = false;
   YYLTYPE loc;

   loc = this->get_location();

   switch (this->oper) {
   case ast_aggregate:
         assert(!"ast_aggregate: Should never get here.");
         break;

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

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

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

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

      error_emitted = type->is_error();

      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:
       if (!state->check_bitwise_operations_allowed(&loc)) {
          error_emitted = true;
       }

       op[0] = this->subexpressions[0]->hir(instructions, state);
       op[1] = this->subexpressions[1]->hir(instructions, state);
       type = shift_result_type(op[0]->type, op[1]->type, this->oper, state,
                                &loc);
       result = new(ctx) ir_expression(operations[this->oper], type,
                                       op[0], op[1]);
       error_emitted = op[0]->type->is_error() || op[1]->type->is_error();
       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 ((op[0]->type->is_array() || op[1]->type->is_array()) &&
                 !state->check_version(120, 300, &loc,
                                       "array comparisons forbidden")) {
	 error_emitted = true;
      } else if ((op[0]->type->contains_opaque() ||
                  op[1]->type->contains_opaque())) {
         _mesa_glsl_error(&loc, state, "opaque type comparisons forbidden");
         error_emitted = true;
      }

      if (error_emitted) {
	 result = new(ctx) ir_constant(false);
      } else {
	 result = do_comparison(ctx, operations[this->oper], op[0], op[1]);
	 assert(result->type == glsl_type::bool_type);
      }
      break;

   case ast_bit_and:
   case ast_bit_xor:
   case ast_bit_or:
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);
      type = bit_logic_result_type(op[0]->type, op[1]->type, this->oper,
                                   state, &loc);
      result = new(ctx) ir_expression(operations[this->oper], type,
				      op[0], op[1]);
      error_emitted = op[0]->type->is_error() || op[1]->type->is_error();
      break;

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

      if (!state->check_bitwise_operations_allowed(&loc)) {
	 error_emitted = true;
      }

      if (!op[0]->type->is_integer()) {
	 _mesa_glsl_error(&loc, state, "operand of `~' must be an integer");
	 error_emitted = true;
      }

      type = error_emitted ? glsl_type::error_type : op[0]->type;
      result = new(ctx) ir_expression(ir_unop_bit_not, type, op[0], NULL);
      break;

   case ast_logic_and: {
      exec_list rhs_instructions;
      op[0] = get_scalar_boolean_operand(instructions, state, this, 0,
					 "LHS", &error_emitted);
      op[1] = get_scalar_boolean_operand(&rhs_instructions, state, this, 1,
					 "RHS", &error_emitted);

      if (rhs_instructions.is_empty()) {
	 result = new(ctx) ir_expression(ir_binop_logic_and, op[0], op[1]);
	 type = result->type;
      } else {
	 ir_variable *const tmp = new(ctx) ir_variable(glsl_type::bool_type,
						       "and_tmp",
						       ir_var_temporary);
	 instructions->push_tail(tmp);

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

	 stmt->then_instructions.append_list(&rhs_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]);
	 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));
	 stmt->else_instructions.push_tail(else_assign);

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

   case ast_logic_or: {
      exec_list rhs_instructions;
      op[0] = get_scalar_boolean_operand(instructions, state, this, 0,
					 "LHS", &error_emitted);
      op[1] = get_scalar_boolean_operand(&rhs_instructions, state, this, 1,
					 "RHS", &error_emitted);

      if (rhs_instructions.is_empty()) {
	 result = new(ctx) ir_expression(ir_binop_logic_or, op[0], op[1]);
	 type = result->type;
      } else {
	 ir_variable *const tmp = new(ctx) ir_variable(glsl_type::bool_type,
						       "or_tmp",
						       ir_var_temporary);
	 instructions->push_tail(tmp);

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

	 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));
	 stmt->then_instructions.push_tail(then_assign);

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

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

   case ast_logic_xor:
      /* From page 33 (page 39 of the PDF) of the GLSL 1.10 spec:
       *
       *    "The logical binary operators and (&&), or ( | | ), and
       *     exclusive or (^^). They operate only on two Boolean
       *     expressions and result in a Boolean expression."
       */
      op[0] = get_scalar_boolean_operand(instructions, state, this, 0, "LHS",
					 &error_emitted);
      op[1] = get_scalar_boolean_operand(instructions, state, this, 1, "RHS",
					 &error_emitted);

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

   case ast_logic_not:
      op[0] = get_scalar_boolean_operand(instructions, state, this, 0,
					 "operand", &error_emitted);

      result = new(ctx) ir_expression(operations[this->oper], glsl_type::bool_type,
				      op[0], NULL);
      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,
			     this->subexpressions[0]->non_lvalue_description,
			     op[0]->clone(ctx, NULL), temp_rhs, false,
			     this->subexpressions[0]->get_location());
      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);

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

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

   case ast_ls_assign:
   case ast_rs_assign: {
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);
      type = shift_result_type(op[0]->type, op[1]->type, this->oper, state,
                               &loc);
      ir_rvalue *temp_rhs = new(ctx) ir_expression(operations[this->oper],
                                                   type, op[0], op[1]);
      result = do_assignment(instructions, state,
			     this->subexpressions[0]->non_lvalue_description,
			     op[0]->clone(ctx, NULL), temp_rhs, false,
                             this->subexpressions[0]->get_location());
      error_emitted = op[0]->type->is_error() || op[1]->type->is_error();
      break;
   }

   case ast_and_assign:
   case ast_xor_assign:
   case ast_or_assign: {
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = this->subexpressions[1]->hir(instructions, state);
      type = bit_logic_result_type(op[0]->type, op[1]->type, this->oper,
                                   state, &loc);
      ir_rvalue *temp_rhs = new(ctx) ir_expression(operations[this->oper],
                                                   type, op[0], op[1]);
      result = do_assignment(instructions, state,
			     this->subexpressions[0]->non_lvalue_description,
			     op[0]->clone(ctx, NULL), temp_rhs, false,
                             this->subexpressions[0]->get_location());
      error_emitted = op[0]->type->is_error() || op[1]->type->is_error();
      break;
   }

   case ast_conditional: {
      /* 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."
       */
      op[0] = get_scalar_boolean_operand(instructions, state, this, 0,
					 "condition", &error_emitted);

      /* 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;
      }

      /* From page 33 (page 39 of the PDF) of the GLSL 1.10 spec:
       *
       *    "The second and third expressions must be the same type, but can
       *    be of any type other than an array."
       */
      if (type->is_array() &&
          !state->check_version(120, 300, &loc,
                                "second and third operands of ?: operator "
                                "cannot be arrays")) {
	 error_emitted = true;
      }

      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 =
	    new(ctx) ir_variable(type, "conditional_tmp", ir_var_temporary);
	 instructions->push_tail(tmp);

	 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]);
	 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]);
	 stmt->else_instructions.push_tail(else_assign);

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

   case ast_pre_inc:
   case ast_pre_dec: {
      this->non_lvalue_description = (this->oper == ast_pre_inc)
	 ? "pre-increment operation" : "pre-decrement operation";

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

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

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

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

   case ast_post_inc:
   case ast_post_dec: {
      this->non_lvalue_description = (this->oper == ast_post_inc)
	 ? "post-increment operation" : "post-decrement operation";
      op[0] = this->subexpressions[0]->hir(instructions, state);
      op[1] = constant_one_for_inc_dec(ctx, op[0]->type);

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

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

      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(ctx, NULL));

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

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

   case ast_field_selection:
      result = _mesa_ast_field_selection_to_hir(this, instructions, state);
      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);

      result = _mesa_ast_array_index_to_hir(ctx, state, op[0], op[1],
					    loc, index_loc);

      if (result->type->is_error())
	 error_emitted = true;

      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);

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

	 result = ir_rvalue::error_value(ctx);
	 error_emitted = true;
      }
      break;
   }

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

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

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

   case ast_bool_constant:
      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.
       */
      exec_node *previous_tail_pred = NULL;
      YYLTYPE previous_operand_loc = loc;

      foreach_list_typed (ast_node, ast, link, &this->expressions) {
	 /* If one of the operands of comma operator does not generate any
	  * code, we want to emit a warning.  At each pass through the loop
	  * previous_tail_pred will point to the last instruction in the
	  * stream *before* processing the previous operand.  Naturally,
	  * instructions->tail_pred will point to the last instruction in the
	  * stream *after* processing the previous operand.  If the two
	  * pointers match, then the previous operand had no effect.
	  *
	  * The warning behavior here differs slightly from GCC.  GCC will
	  * only emit a warning if none of the left-hand operands have an
	  * effect.  However, it will emit a warning for each.  I believe that
	  * there are some cases in C (especially with GCC extensions) where
	  * it is useful to have an intermediate step in a sequence have no
	  * effect, but I don't think these cases exist in GLSL.  Either way,
	  * it would be a giant hassle to replicate that behavior.
	  */
	 if (previous_tail_pred == instructions->tail_pred) {
	    _mesa_glsl_warning(&previous_operand_loc, state,
			       "left-hand operand of comma expression has "
			       "no effect");
	 }

	 /* tail_pred is directly accessed instead of using the get_tail()
	  * method for performance reasons.  get_tail() has extra code to
	  * return NULL when the list is empty.  We don't care about that
	  * here, so using tail_pred directly is fine.
	  */
	 previous_tail_pred = instructions->tail_pred;
	 previous_operand_loc = ast->get_location();

	 result = ast->hir(instructions, state);
      }

      /* Any errors should have already been emitted in the loop above.
       */
      error_emitted = true;
      break;
   }
   }
   type = NULL; /* use result->type, not type. */
   assert(result != NULL);

   if (result->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(YYLTYPE *loc, const glsl_type *base, ast_node *array_size,
		   struct _mesa_glsl_parse_state *state)
{
   unsigned length = 0;

   if (base == NULL)
      return glsl_type::error_type;

   /* From page 19 (page 25) of the GLSL 1.20 spec:
    *
    *     "Only one-dimensional arrays may be declared."
    */
   if (base->is_array()) {
      _mesa_glsl_error(loc, state,
		       "invalid array of `%s' (only one-dimensional arrays "
		       "may be declared)",
		       base->name);
      return glsl_type::error_type;
   }

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

      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];

               /* If the array size is const (and we've verified that
                * it is) then no instructions should have been emitted
                * when we converted it to HIR.  If they were emitted,
                * then either the array size isn't const after all, or
                * we are emitting unnecessary instructions.
                */
               assert(dummy_instructions.is_empty());
	    }
	 }
      }
   }

   const glsl_type *array_type = glsl_type::get_array_instance(base, length);
   return array_type != NULL ? array_type : glsl_type::error_type;
}


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

   type = state->symbols->get_type(this->type_name);
   *name = this->type_name;

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

   return type;
}

const glsl_type *
ast_fully_specified_type::glsl_type(const char **name,
                                    struct _mesa_glsl_parse_state *state) const
{
   const struct glsl_type *type = this->specifier->glsl_type(name, state);

   if (type == NULL)
      return NULL;

   if (type->base_type == GLSL_TYPE_FLOAT
       && state->es_shader
       && state->target == fragment_shader
       && this->qualifier.precision == ast_precision_none
       && state->symbols->get_variable("#default precision") == NULL) {
      YYLTYPE loc = this->get_location();
      _mesa_glsl_error(&loc, state,
                       "no precision specified this scope for type `%s'",
                       type->name);
   }

   return type;
}

/**
 * Determine whether a toplevel variable declaration declares a varying.  This
 * function operates by examining the variable's mode and the shader target,
 * so it correctly identifies linkage variables regardless of whether they are
 * declared using the deprecated "varying" syntax or the new "in/out" syntax.
 *
 * Passing a non-toplevel variable declaration (e.g. a function parameter) to
 * this function will produce undefined results.
 */
static bool
is_varying_var(ir_variable *var, _mesa_glsl_parser_targets target)
{
   switch (target) {
   case vertex_shader:
      return var->mode == ir_var_shader_out;
   case fragment_shader:
      return var->mode == ir_var_shader_in;
   default:
      return var->mode == ir_var_shader_out || var->mode == ir_var_shader_in;
   }
}


/**
 * Matrix layout qualifiers are only allowed on certain types
 */
static void
validate_matrix_layout_for_type(struct _mesa_glsl_parse_state *state,
				YYLTYPE *loc,
                                const glsl_type *type,
                                ir_variable *var)
{
   if (var && !var->is_in_uniform_block()) {
      /* Layout qualifiers may only apply to interface blocks and fields in
       * them.
       */
      _mesa_glsl_error(loc, state,
                       "uniform block layout qualifiers row_major and "
                       "column_major may not be applied to variables "
                       "outside of uniform blocks");
   } else if (!type->is_matrix()) {
      /* The OpenGL ES 3.0 conformance tests did not originally allow
       * matrix layout qualifiers on non-matrices.  However, the OpenGL
       * 4.4 and OpenGL ES 3.0 (revision TBD) specifications were
       * amended to specifically allow these layouts on all types.  Emit
       * a warning so that people know their code may not be portable.
       */
      _mesa_glsl_warning(loc, state,
                         "uniform block layout qualifiers row_major and "
                         "column_major applied to non-matrix types may "
                         "be rejected by older compilers");
   } else if (type->is_record()) {
      /* We allow 'layout(row_major)' on structure types because it's the only
       * way to get row-major layouts on matrices contained in structures.
       */
      _mesa_glsl_warning(loc, state,
                         "uniform block layout qualifiers row_major and "
                         "column_major applied to structure types is not "
                         "strictly conformant and may be rejected by other "
                         "compilers");
   }
}

static bool
validate_binding_qualifier(struct _mesa_glsl_parse_state *state,
                           YYLTYPE *loc,
                           ir_variable *var,
                           const ast_type_qualifier *qual)
{
   if (var->mode != ir_var_uniform) {
      _mesa_glsl_error(loc, state,
                       "the \"binding\" qualifier only applies to uniforms");
      return false;
   }

   if (qual->binding < 0) {
      _mesa_glsl_error(loc, state, "binding values must be >= 0");
      return false;
   }

   const struct gl_context *const ctx = state->ctx;
   unsigned elements = var->type->is_array() ? var->type->length : 1;
   unsigned max_index = qual->binding + elements - 1;

   if (var->type->is_interface()) {
      /* UBOs.  From page 60 of the GLSL 4.20 specification:
       * "If the binding point for any uniform block instance is less than zero,
       *  or greater than or equal to the implementation-dependent maximum
       *  number of uniform buffer bindings, a compilation error will occur.
       *  When the binding identifier is used with a uniform block instanced as
       *  an array of size N, all elements of the array from binding through
       *  binding + N – 1 must be within this range."
       *
       * The implementation-dependent maximum is GL_MAX_UNIFORM_BUFFER_BINDINGS.
       */
      if (max_index >= ctx->Const.MaxUniformBufferBindings) {
         _mesa_glsl_error(loc, state, "layout(binding = %d) for %d UBOs exceeds "
                          "the maximum number of UBO binding points (%d)",
                          qual->binding, elements,
                          ctx->Const.MaxUniformBufferBindings);
         return false;
      }
   } else if (var->type->is_sampler() ||
              (var->type->is_array() && var->type->fields.array->is_sampler())) {
      /* Samplers.  From page 63 of the GLSL 4.20 specification:
       * "If the binding is less than zero, or greater than or equal to the
       *  implementation-dependent maximum supported number of units, a
       *  compilation error will occur. When the binding identifier is used
       *  with an array of size N, all elements of the array from binding
       *  through binding + N - 1 must be within this range."
       */
      unsigned limit = 0;
      switch (state->target) {
      case vertex_shader:
         limit = ctx->Const.VertexProgram.MaxTextureImageUnits;
         break;
      case geometry_shader:
         limit = ctx->Const.GeometryProgram.MaxTextureImageUnits;
         break;
      case fragment_shader:
         limit = ctx->Const.FragmentProgram.MaxTextureImageUnits;
         break;
      }

      if (max_index >= limit) {
         _mesa_glsl_error(loc, state, "layout(binding = %d) for %d samplers "
                          "exceeds the maximum number of texture image units "
                          "(%d)", qual->binding, elements, limit);

         return false;
      }
   } else if (var->type->contains_atomic()) {
      assert(ctx->Const.MaxAtomicBufferBindings <= MAX_COMBINED_ATOMIC_BUFFERS);
      if (unsigned(qual->binding) >= ctx->Const.MaxAtomicBufferBindings) {
         _mesa_glsl_error(loc, state, "layout(binding = %d) exceeds the "
                          " maximum number of atomic counter buffer bindings"
                          "(%d)", qual->binding,
                          ctx->Const.MaxAtomicBufferBindings);

         return false;
      }
   } else {
      _mesa_glsl_error(loc, state,
                       "the \"binding\" qualifier only applies to uniform "
                       "blocks, samplers, atomic counters, or arrays thereof");
      return false;
   }

   return true;
}


static glsl_interp_qualifier
interpret_interpolation_qualifier(const struct ast_type_qualifier *qual,
                                  ir_variable_mode mode,
                                  struct _mesa_glsl_parse_state *state,
                                  YYLTYPE *loc)
{
   glsl_interp_qualifier interpolation;
   if (qual->flags.q.flat)
      interpolation = INTERP_QUALIFIER_FLAT;
   else if (qual->flags.q.noperspective)
      interpolation = INTERP_QUALIFIER_NOPERSPECTIVE;
   else if (qual->flags.q.smooth)
      interpolation = INTERP_QUALIFIER_SMOOTH;
   else
      interpolation = INTERP_QUALIFIER_NONE;

   if (interpolation != INTERP_QUALIFIER_NONE) {
      if (mode != ir_var_shader_in && mode != ir_var_shader_out) {
         _mesa_glsl_error(loc, state,
                          "interpolation qualifier `%s' can only be applied to "
                          "shader inputs or outputs.",
                          interpolation_string(interpolation));

      }

      if ((state->target == vertex_shader && mode == ir_var_shader_in) ||
          (state->target == fragment_shader && mode == ir_var_shader_out)) {
         _mesa_glsl_error(loc, state,
                          "interpolation qualifier `%s' cannot be applied to "
                          "vertex shader inputs or fragment shader outputs",
                          interpolation_string(interpolation));
      }
   }

   return interpolation;
}


static void
validate_explicit_location(const struct ast_type_qualifier *qual,
                           ir_variable *var,
                           struct _mesa_glsl_parse_state *state,
                           YYLTYPE *loc)
{
   bool fail = false;

   /* In the vertex shader only shader inputs can be given explicit
    * locations.
    *
    * In the fragment shader only shader outputs can be given explicit
    * locations.
    */
   switch (state->target) {
   case vertex_shader:
      if (var->mode == ir_var_shader_in) {
         if (!state->check_explicit_attrib_location_allowed(loc, var))
            return;

         break;
      }

      fail = true;
      break;

   case geometry_shader:
      _mesa_glsl_error(loc, state,
                       "geometry shader variables cannot be given "
                       "explicit locations");
      return;

   case fragment_shader:
      if (var->mode == ir_var_shader_out) {
         if (!state->check_explicit_attrib_location_allowed(loc, var))
            return;

         break;
      }

      fail = true;
      break;
   };

   if (fail) {
      _mesa_glsl_error(loc, state,
                       "%s cannot be given an explicit location in %s shader",
                       mode_string(var),
		       _mesa_glsl_shader_target_name(state->target));
   } else {
      var->explicit_location = true;

      /* This bit of silliness is needed because invalid explicit locations
       * are supposed to be flagged during linking.  Small negative values
       * biased by VERT_ATTRIB_GENERIC0 or FRAG_RESULT_DATA0 could alias
       * built-in values (e.g., -16+VERT_ATTRIB_GENERIC0 = VERT_ATTRIB_POS).
       * The linker needs to be able to differentiate these cases.  This
       * ensures that negative values stay negative.
       */
      if (qual->location >= 0) {
         var->location = (state->target == vertex_shader)
            ? (qual->location + VERT_ATTRIB_GENERIC0)
            : (qual->location + FRAG_RESULT_DATA0);
      } else {
         var->location = qual->location;
      }

      if (qual->flags.q.explicit_index) {
         /* From the GLSL 4.30 specification, section 4.4.2 (Output
          * Layout Qualifiers):
          *
          * "It is also a compile-time error if a fragment shader
          *  sets a layout index to less than 0 or greater than 1."
          *
          * Older specifications don't mandate a behavior; we take
          * this as a clarification and always generate the error.
          */
         if (qual->index < 0 || qual->index > 1) {
            _mesa_glsl_error(loc, state,
                             "explicit index may only be 0 or 1");
         } else {
            var->explicit_index = true;
            var->index = qual->index;
         }
      }
   }

   return;
}

static void
apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
				 ir_variable *var,
				 struct _mesa_glsl_parse_state *state,
				 YYLTYPE *loc,
                                 bool is_parameter)
{
   STATIC_ASSERT(sizeof(qual->flags.q) <= sizeof(qual->flags.i));

   if (qual->flags.q.invariant) {
      if (var->used) {
	 _mesa_glsl_error(loc, state,
			  "variable `%s' may not be redeclared "
			  "`invariant' after being used",
			  var->name);
      } else {
	 var->invariant = 1;
      }
   }

   if (qual->flags.q.constant || qual->flags.q.attribute
       || qual->flags.q.uniform
       || (qual->flags.q.varying && (state->target == fragment_shader)))
      var->read_only = 1;

   if (qual->flags.q.centroid)
      var->centroid = 1;

   if (qual->flags.q.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));
   }

   /* Section 6.1.1 (Function Calling Conventions) of the GLSL 1.10 spec says:
    *
    *     "However, the const qualifier cannot be used with out or inout."
    *
    * The same section of the GLSL 4.40 spec further clarifies this saying:
    *
    *     "The const qualifier cannot be used with out or inout, or a
    *     compile-time error results."
    */
   if (is_parameter && qual->flags.q.constant && qual->flags.q.out) {
      _mesa_glsl_error(loc, state,
                       "`const' may not be applied to `out' or `inout' "
                       "function parameters");
   }

   /* If there is no qualifier that changes the mode of the variable, leave
    * the setting alone.
    */
   if (qual->flags.q.in && qual->flags.q.out)
      var->mode = ir_var_function_inout;
   else if (qual->flags.q.in)
      var->mode = is_parameter ? ir_var_function_in : ir_var_shader_in;
   else if (qual->flags.q.attribute
	    || (qual->flags.q.varying && (state->target == fragment_shader)))
      var->mode = ir_var_shader_in;
   else if (qual->flags.q.out)
      var->mode = is_parameter ? ir_var_function_out : ir_var_shader_out;
   else if (qual->flags.q.varying && (state->target == vertex_shader))
      var->mode = ir_var_shader_out;
   else if (qual->flags.q.uniform)
      var->mode = ir_var_uniform;

   if (!is_parameter && is_varying_var(var, state->target)) {
      /* This variable is being used to link data between shader stages (in
       * pre-glsl-1.30 parlance, it's a "varying").  Check that it has a type
       * that is allowed for such purposes.
       *
       * 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."
       *
       * This was relaxed in GLSL version 1.30 and GLSL ES version 3.00.  From
       * page 31 (page 37 of the PDF) of the GLSL 1.30 spec:
       *
       *     "Fragment inputs can only be signed and unsigned integers and
       *     integer vectors, float, floating-point vectors, matrices, or
       *     arrays of these. Structures cannot be input.
       *
       * Similar text exists in the section on vertex shader outputs.
       *
       * Similar text exists in the GLSL ES 3.00 spec, except that the GLSL ES
       * 3.00 spec allows structs as well.  Varying structs are also allowed
       * in GLSL 1.50.
       */
      switch (var->type->get_scalar_type()->base_type) {
      case GLSL_TYPE_FLOAT:
         /* Ok in all GLSL versions */
         break;
      case GLSL_TYPE_UINT:
      case GLSL_TYPE_INT:
         if (state->is_version(130, 300))
            break;
         _mesa_glsl_error(loc, state,
                          "varying variables must be of base type float in %s",
                          state->get_version_string());
         break;
      case GLSL_TYPE_STRUCT:
         if (state->is_version(150, 300))
            break;
         _mesa_glsl_error(loc, state,
                          "varying variables may not be of type struct");
         break;
      default:
         _mesa_glsl_error(loc, state, "illegal type for a varying variable");
         break;
      }
   }

   if (state->all_invariant && (state->current_function == NULL)) {
      switch (state->target) {
      case vertex_shader:
	 if (var->mode == ir_var_shader_out)
	    var->invariant = true;
	 break;
      case geometry_shader:
	 if ((var->mode == ir_var_shader_in)
             || (var->mode == ir_var_shader_out))
	    var->invariant = true;
	 break;
      case fragment_shader:
	 if (var->mode == ir_var_shader_in)
	    var->invariant = true;
	 break;
      }
   }

   var->interpolation =
      interpret_interpolation_qualifier(qual, (ir_variable_mode) var->mode,
                                        state, loc);

   var->pixel_center_integer = qual->flags.q.pixel_center_integer;
   var->origin_upper_left = qual->flags.q.origin_upper_left;
   if ((qual->flags.q.origin_upper_left || qual->flags.q.pixel_center_integer)
       && (strcmp(var->name, "gl_FragCoord") != 0)) {
      const char *const qual_string = (qual->flags.q.origin_upper_left)
	 ? "origin_upper_left" : "pixel_center_integer";

      _mesa_glsl_error(loc, state,
		       "layout qualifier `%s' can only be applied to "
		       "fragment shader input `gl_FragCoord'",
		       qual_string);
   }

   if (qual->flags.q.explicit_location) {
      validate_explicit_location(qual, var, state, loc);
   } else if (qual->flags.q.explicit_index) {
	 _mesa_glsl_error(loc, state,
			  "explicit index requires explicit location");
   }

   if (qual->flags.q.explicit_binding &&
       validate_binding_qualifier(state, loc, var, qual)) {
      var->explicit_binding = true;
      var->binding = qual->binding;
   }

   if (var->type->contains_atomic()) {
      if (var->mode == ir_var_uniform) {
         if (var->explicit_binding) {
            unsigned *offset = &state->atomic_counter_offsets[var->binding];

            if (*offset % ATOMIC_COUNTER_SIZE)
               _mesa_glsl_error(loc, state,
                                "misaligned atomic counter offset");

            var->atomic.offset = *offset;
            *offset += var->type->atomic_size();

         } else {
            _mesa_glsl_error(loc, state,
                             "atomic counters require explicit binding point");
         }
      } else if (var->mode != ir_var_function_in) {
         _mesa_glsl_error(loc, state, "atomic counters may only be declared as "
                          "function parameters or uniform-qualified "
                          "global variables");
      }
   }

   /* Does the declaration use the deprecated 'attribute' or 'varying'
    * keywords?
    */
   const bool uses_deprecated_qualifier = qual->flags.q.attribute
      || qual->flags.q.varying;

   /* Is the 'layout' keyword used with parameters that allow relaxed checking.
    * Many implementations of GL_ARB_fragment_coord_conventions_enable and some
    * implementations (only Mesa?) GL_ARB_explicit_attrib_location_enable
    * allowed the layout qualifier to be used with 'varying' and 'attribute'.
    * These extensions and all following extensions that add the 'layout'
    * keyword have been modified to require the use of 'in' or 'out'.
    *
    * The following extension do not allow the deprecated keywords:
    *
    *    GL_AMD_conservative_depth
    *    GL_ARB_conservative_depth
    *    GL_ARB_gpu_shader5
    *    GL_ARB_separate_shader_objects
    *    GL_ARB_tesselation_shader
    *    GL_ARB_transform_feedback3
    *    GL_ARB_uniform_buffer_object
    *
    * It is unknown whether GL_EXT_shader_image_load_store or GL_NV_gpu_shader5
    * allow layout with the deprecated keywords.
    */
   const bool relaxed_layout_qualifier_checking =
      state->ARB_fragment_coord_conventions_enable;

   if (qual->has_layout() && uses_deprecated_qualifier) {
      if (relaxed_layout_qualifier_checking) {
	 _mesa_glsl_warning(loc, state,
			    "`layout' qualifier may not be used with "
			    "`attribute' or `varying'");
      } else {
	 _mesa_glsl_error(loc, state,
			  "`layout' qualifier may not be used with "
			  "`attribute' or `varying'");
      }
   }

   /* Layout qualifiers for gl_FragDepth, which are enabled by extension
    * AMD_conservative_depth.
    */
   int depth_layout_count = qual->flags.q.depth_any
      + qual->flags.q.depth_greater
      + qual->flags.q.depth_less
      + qual->flags.q.depth_unchanged;
   if (depth_layout_count > 0
       && !state->AMD_conservative_depth_enable
       && !state->ARB_conservative_depth_enable) {
       _mesa_glsl_error(loc, state,
                        "extension GL_AMD_conservative_depth or "
                        "GL_ARB_conservative_depth must be enabled "
			"to use depth layout qualifiers");
   } else if (depth_layout_count > 0
              && strcmp(var->name, "gl_FragDepth") != 0) {
       _mesa_glsl_error(loc, state,
                        "depth layout qualifiers can be applied only to "
                        "gl_FragDepth");
   } else if (depth_layout_count > 1
              && strcmp(var->name, "gl_FragDepth") == 0) {
      _mesa_glsl_error(loc, state,
                       "at most one depth layout qualifier can be applied to "
                       "gl_FragDepth");
   }
   if (qual->flags.q.depth_any)
      var->depth_layout = ir_depth_layout_any;
   else if (qual->flags.q.depth_greater)
      var->depth_layout = ir_depth_layout_greater;
   else if (qual->flags.q.depth_less)
      var->depth_layout = ir_depth_layout_less;
   else if (qual->flags.q.depth_unchanged)
       var->depth_layout = ir_depth_layout_unchanged;
   else
       var->depth_layout = ir_depth_layout_none;

   if (qual->flags.q.std140 ||
       qual->flags.q.packed ||
       qual->flags.q.shared) {
      _mesa_glsl_error(loc, state,
                       "uniform block layout qualifiers std140, packed, and "
		       "shared can only be applied to uniform blocks, not "
		       "members");
   }

   if (qual->flags.q.row_major || qual->flags.q.column_major) {
      validate_matrix_layout_for_type(state, loc, var->type, var);
   }
}

/**
 * Get the variable that is being redeclared by this declaration
 *
 * Semantic checks to verify the validity of the redeclaration are also
 * performed.  If semantic checks fail, compilation error will be emitted via
 * \c _mesa_glsl_error, but a non-\c NULL pointer will still be returned.
 *
 * \returns
 * A pointer to an existing variable in the current scope if the declaration
 * is a redeclaration, \c NULL otherwise.
 */
static ir_variable *
get_variable_being_redeclared(ir_variable *var, YYLTYPE loc,
                              struct _mesa_glsl_parse_state *state,
                              bool allow_all_redeclarations)
{
   /* Check if this declaration is actually a re-declaration, either to
    * resize an array or add qualifiers to an existing variable.
    *
    * This is allowed for variables in the current scope, or when at
    * global scope (for built-ins in the implicit outer scope).
    */
   ir_variable *earlier = state->symbols->get_variable(var->name);
   if (earlier == NULL ||
       (state->current_function != NULL &&
	!state->symbols->name_declared_this_scope(var->name))) {
      return NULL;
   }


   /* 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 (earlier->type->is_unsized_array() && 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.
       */

      const unsigned size = unsigned(var->type->array_size());
      check_builtin_array_max_size(var->name, size, loc, state);
      if ((size > 0) && (size <= earlier->max_array_access)) {
	 _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 if ((state->ARB_fragment_coord_conventions_enable ||
               state->is_version(150, 0))
	      && strcmp(var->name, "gl_FragCoord") == 0
	      && earlier->type == var->type
	      && earlier->mode == var->mode) {
      /* Allow redeclaration of gl_FragCoord for ARB_fcc layout
       * qualifiers.
       */
      earlier->origin_upper_left = var->origin_upper_left;
      earlier->pixel_center_integer = var->pixel_center_integer;

      /* According to section 4.3.7 of the GLSL 1.30 spec,
       * the following built-in varaibles can be redeclared with an
       * interpolation qualifier:
       *    * gl_FrontColor
       *    * gl_BackColor
       *    * gl_FrontSecondaryColor
       *    * gl_BackSecondaryColor
       *    * gl_Color
       *    * gl_SecondaryColor
       */
   } else if (state->is_version(130, 0)
	      && (strcmp(var->name, "gl_FrontColor") == 0
		  || strcmp(var->name, "gl_BackColor") == 0
		  || strcmp(var->name, "gl_FrontSecondaryColor") == 0
		  || strcmp(var->name, "gl_BackSecondaryColor") == 0
		  || strcmp(var->name, "gl_Color") == 0
		  || strcmp(var->name, "gl_SecondaryColor") == 0)
	      && earlier->type == var->type
	      && earlier->mode == var->mode) {
      earlier->interpolation = var->interpolation;

      /* Layout qualifiers for gl_FragDepth. */
   } else if ((state->AMD_conservative_depth_enable ||
               state->ARB_conservative_depth_enable)
	      && strcmp(var->name, "gl_FragDepth") == 0
	      && earlier->type == var->type
	      && earlier->mode == var->mode) {

      /** From the AMD_conservative_depth spec:
       *     Within any shader, the first redeclarations of gl_FragDepth
       *     must appear before any use of gl_FragDepth.
       */
      if (earlier->used) {
	 _mesa_glsl_error(&loc, state,
			  "the first redeclaration of gl_FragDepth "
			  "must appear before any use of gl_FragDepth");
      }

      /* Prevent inconsistent redeclaration of depth layout qualifier. */
      if (earlier->depth_layout != ir_depth_layout_none
	  && earlier->depth_layout != var->depth_layout) {
	 _mesa_glsl_error(&loc, state,
			  "gl_FragDepth: depth layout is declared here "
			  "as '%s, but it was previously declared as "
			  "'%s'",
			  depth_layout_string(var->depth_layout),
			  depth_layout_string(earlier->depth_layout));
      }

      earlier->depth_layout = var->depth_layout;

   } else if (allow_all_redeclarations) {
      if (earlier->mode != var->mode) {
         _mesa_glsl_error(&loc, state,
                          "redeclaration of `%s' with incorrect qualifiers",
                          var->name);
      } else if (earlier->type != var->type) {
         _mesa_glsl_error(&loc, state,
                          "redeclaration of `%s' has incorrect type",
                          var->name);
      }
   } else {
      _mesa_glsl_error(&loc, state, "`%s' redeclared", var->name);
   }

   return earlier;
}

/**
 * Generate the IR for an initializer in a variable declaration
 */
ir_rvalue *
process_initializer(ir_variable *var, ast_declaration *decl,
		    ast_fully_specified_type *type,
		    exec_list *initializer_instructions,
		    struct _mesa_glsl_parse_state *state)
{
   ir_rvalue *result = 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 (var->mode == ir_var_uniform) {
      state->check_version(120, 0, &initializer_loc,
                           "cannot initialize uniforms");
   }

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

   if ((var->mode == ir_var_shader_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(state) ir_dereference_variable(var);
   ir_rvalue *rhs = decl->initializer->hir(initializer_instructions,
					   state);

   /* Calculate the constant value if this is a const or uniform
    * declaration.
    */
   if (type->qualifier.flags.q.constant
       || type->qualifier.flags.q.uniform) {
      ir_rvalue *new_rhs = validate_assignment(state, initializer_loc,
                                               var->type, rhs, true);
      if (new_rhs != NULL) {
	 rhs = new_rhs;

	 ir_constant *constant_value = rhs->constant_expression_value();
	 if (!constant_value) {
            /* If ARB_shading_language_420pack is enabled, initializers of
             * const-qualified local variables do not have to be constant
             * expressions. Const-qualified global variables must still be
             * initialized with constant expressions.
             */
            if (!state->ARB_shading_language_420pack_enable
                || state->current_function == NULL) {
               _mesa_glsl_error(& initializer_loc, state,
                                "initializer of %s variable `%s' must be a "
                                "constant expression",
                                (type->qualifier.flags.q.constant)
                                ? "const" : "uniform",
                                decl->identifier);
               if (var->type->is_numeric()) {
                  /* Reduce cascading errors. */
                  var->constant_value = ir_constant::zero(state, var->type);
               }
            }
         } else {
	    rhs = constant_value;
	    var->constant_value = constant_value;
	 }
      } else {
	 if (var->type->is_numeric()) {
	    /* Reduce cascading errors. */
	    var->constant_value = ir_constant::zero(state, var->type);
	 }
      }
   }

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

      /* Never emit code to initialize a uniform.
       */
      const glsl_type *initializer_type;
      if (!type->qualifier.flags.q.uniform) {
	 result = do_assignment(initializer_instructions, state,
				NULL,
				lhs, rhs, true,
				type->get_location());
	 initializer_type = result->type;
      } else
	 initializer_type = rhs->type;

      var->constant_initializer = rhs->constant_expression_value();
      var->has_initializer = true;

      /* If the declared variable is an unsized array, it must inherrit
       * its full type from the initializer.  A declaration such as
       *
       *     uniform float a[] = float[](1.0, 2.0, 3.0, 3.0);
       *
       * becomes
       *
       *     uniform float a[4] = float[](1.0, 2.0, 3.0, 3.0);
       *
       * The assignment generated in the if-statement (below) will also
       * automatically handle this case for non-uniforms.
       *
       * If the declared variable is not an array, the types must
       * already match exactly.  As a result, the type assignment
       * here can be done unconditionally.  For non-uniforms the call
       * to do_assignment can change the type of the initializer (via
       * the implicit conversion rules).  For uniforms the initializer
       * must be a constant expression, and the type of that expression
       * was validated above.
       */
      var->type = initializer_type;

      var->read_only = temp;
   }

   return result;
}


/**
 * Do additional processing necessary for geometry shader input declarations
 * (this covers both interface blocks arrays and bare input variables).
 */
static void
handle_geometry_shader_input_decl(struct _mesa_glsl_parse_state *state,
                                  YYLTYPE loc, ir_variable *var)
{
   unsigned num_vertices = 0;
   if (state->gs_input_prim_type_specified) {
      num_vertices = vertices_per_prim(state->gs_input_prim_type);
   }

   /* Geometry shader input variables must be arrays.  Caller should have
    * reported an error for this.
    */
   if (!var->type->is_array()) {
      assert(state->error);

      /* To avoid cascading failures, short circuit the checks below. */
      return;
   }

   if (var->type->is_unsized_array()) {
      /* Section 4.3.8.1 (Input Layout Qualifiers) of the GLSL 1.50 spec says:
       *
       *   All geometry shader input unsized array declarations will be
       *   sized by an earlier input layout qualifier, when present, as per
       *   the following table.
       *
       * Followed by a table mapping each allowed input layout qualifier to
       * the corresponding input length.
       */
      if (num_vertices != 0)
         var->type = glsl_type::get_array_instance(var->type->fields.array,
                                                   num_vertices);
   } else {
      /* Section 4.3.8.1 (Input Layout Qualifiers) of the GLSL 1.50 spec
       * includes the following examples of compile-time errors:
       *
       *   // code sequence within one shader...
       *   in vec4 Color1[];    // size unknown
       *   ...Color1.length()...// illegal, length() unknown
       *   in vec4 Color2[2];   // size is 2
       *   ...Color1.length()...// illegal, Color1 still has no size
       *   in vec4 Color3[3];   // illegal, input sizes are inconsistent
       *   layout(lines) in;    // legal, input size is 2, matching
       *   in vec4 Color4[3];   // illegal, contradicts layout
       *   ...
       *
       * To detect the case illustrated by Color3, we verify that the size of
       * an explicitly-sized array matches the size of any previously declared
       * explicitly-sized array.  To detect the case illustrated by Color4, we
       * verify that the size of an explicitly-sized array is consistent with
       * any previously declared input layout.
       */
      if (num_vertices != 0 && var->type->length != num_vertices) {
         _mesa_glsl_error(&loc, state,
                          "geometry shader input size contradicts previously"
                          " declared layout (size is %u, but layout requires a"
                          " size of %u)", var->type->length, num_vertices);
      } else if (state->gs_input_size != 0 &&
                 var->type->length != state->gs_input_size) {
         _mesa_glsl_error(&loc, state,
                          "geometry shader input sizes are "
                          "inconsistent (size is %u, but a previous "
                          "declaration has size %u)",
                          var->type->length, state->gs_input_size);
      } else {
         state->gs_input_size = var->type->length;
      }
   }
}


void
validate_identifier(const char *identifier, YYLTYPE loc,
                    struct _mesa_glsl_parse_state *state)
{
   /* 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(identifier, "gl_", 3) == 0) {
      _mesa_glsl_error(&loc, state,
                       "identifier `%s' uses reserved `gl_' prefix",
                       identifier);
   } else if (strstr(identifier, "__")) {
      /* From page 14 (page 20 of the PDF) of the GLSL 1.10
       * spec:
       *
       *     "In addition, all identifiers containing two
       *      consecutive underscores (__) are reserved as
       *      possible future keywords."
       */
      _mesa_glsl_error(&loc, state,
                       "identifier `%s' uses reserved `__' string",
                       identifier);
   }
}


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");
      }

      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", decl->identifier);
	 } else if ((state->target == vertex_shader)
	       && (earlier->mode != ir_var_shader_out)) {
	    _mesa_glsl_error(& loc, state,
			     "`%s' cannot be marked invariant, vertex shader "
			     "outputs only", decl->identifier);
	 } else if ((state->target == fragment_shader)
	       && (earlier->mode != ir_var_shader_in)) {
	    _mesa_glsl_error(& loc, state,
			     "`%s' cannot be marked invariant, fragment shader "
			     "inputs only", decl->identifier);
	 } else if (earlier->used) {
	    _mesa_glsl_error(& loc, state,
			     "variable `%s' may not be redeclared "
			     "`invariant' after being used",
			     earlier->name);
	 } 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->glsl_type(& type_name, state);

   /* An offset-qualified atomic counter declaration sets the default
    * offset for the next declaration within the same atomic counter
    * buffer.
    */
   if (decl_type && decl_type->contains_atomic()) {
      if (type->qualifier.flags.q.explicit_binding &&
          type->qualifier.flags.q.explicit_offset)
         state->atomic_counter_offsets[type->qualifier.binding] =
            type->qualifier.offset;
   }

   if (this->declarations.is_empty()) {
      /* If there is no structure involved in the program text, there are two
       * possible scenarios:
       *
       * - The program text contained something like 'vec4;'.  This is an
       *   empty declaration.  It is valid but weird.  Emit a warning.
       *
       * - The program text contained something like 'S;' and 'S' is not the
       *   name of a known structure type.  This is both invalid and weird.
       *   Emit an error.
       *
       * - The program text contained something like 'mediump float;'
       *   when the programmer probably meant 'precision mediump
       *   float;' Emit a warning with a description of what they
       *   probably meant to do.
       *
       * Note that if decl_type is NULL and there is a structure involved,
       * there must have been some sort of error with the structure.  In this
       * case we assume that an error was already generated on this line of
       * code for the structure.  There is no need to generate an additional,
       * confusing error.
       */
      assert(this->type->specifier->structure == NULL || decl_type != NULL
	     || state->error);

      if (decl_type == NULL) {
         _mesa_glsl_error(&loc, state,
                          "invalid type `%s' in empty declaration",
                          type_name);
      } else if (decl_type->base_type == GLSL_TYPE_ATOMIC_UINT) {
         /* Empty atomic counter declarations are allowed and useful
          * to set the default offset qualifier.
          */
         return NULL;
      } else if (this->type->qualifier.precision != ast_precision_none) {
         if (this->type->specifier->structure != NULL) {
            _mesa_glsl_error(&loc, state,
                             "precision qualifiers can't be applied "
                             "to structures");
         } else {
            static const char *const precision_names[] = {
               "highp",
               "highp",
               "mediump",
               "lowp"
            };

            _mesa_glsl_warning(&loc, state,
                               "empty declaration with precision qualifier, "
                               "to set the default precision, use "
                               "`precision %s %s;'",
                               precision_names[this->type->qualifier.precision],
                               type_name);
         }
      } else {
         _mesa_glsl_warning(&loc, state, "empty declaration");
      }
   }

   foreach_list_typed (ast_declaration, decl, link, &this->declarations) {
      const struct glsl_type *var_type;
      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(&loc, decl_type, decl->array_size,
				       state);
	 if (var_type->is_error())
	    continue;
      } else {
	 var_type = decl_type;
      }

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

      /* The 'varying in' and 'varying out' qualifiers can only be used with
       * ARB_geometry_shader4 and EXT_geometry_shader4, which we don't support
       * yet.
       */
      if (this->type->qualifier.flags.q.varying) {
         if (this->type->qualifier.flags.q.in) {
            _mesa_glsl_error(& loc, state,
                             "`varying in' qualifier in declaration of "
                             "`%s' only valid for geometry shaders using "
                             "ARB_geometry_shader4 or EXT_geometry_shader4",
                             decl->identifier);
         } else if (this->type->qualifier.flags.q.out) {
            _mesa_glsl_error(& loc, state,
                             "`varying out' qualifier in declaration of "
                             "`%s' only valid for geometry shaders using "
                             "ARB_geometry_shader4 or EXT_geometry_shader4",
                             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 and GLSL ES 3.00.  It is also relaxed by
       * any extension that adds the 'layout' keyword.
       */
      if (!state->is_version(130, 300)
	  && !state->has_explicit_attrib_location()
	  && !state->ARB_fragment_coord_conventions_enable) {
	 if (this->type->qualifier.flags.q.out) {
	    _mesa_glsl_error(& loc, state,
			     "`out' qualifier in declaration of `%s' "
			     "only valid for function parameters in %s",
			     decl->identifier, state->get_version_string());
	 }
	 if (this->type->qualifier.flags.q.in) {
	    _mesa_glsl_error(& loc, state,
			     "`in' qualifier in declaration of `%s' "
			     "only valid for function parameters in %s",
			     decl->identifier, state->get_version_string());
	 }
	 /* FINISHME: Test for other invalid qualifiers. */
      }

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

      if (this->type->qualifier.flags.q.invariant) {
	 if ((state->target == vertex_shader) &&
             var->mode != ir_var_shader_out) {
	    _mesa_glsl_error(& loc, state,
			     "`%s' cannot be marked invariant, vertex shader "
			     "outputs only", var->name);
	 } else if ((state->target == fragment_shader) &&
		    var->mode != ir_var_shader_in) {
	    /* FINISHME: Note that this doesn't work for invariant on
	     * a function signature inval
	     */
	    _mesa_glsl_error(& loc, state,
			     "`%s' cannot be marked invariant, fragment shader "
			     "inputs only", 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.flags.q.attribute) {
	    mode = "attribute";
	 } else if (this->type->qualifier.flags.q.uniform) {
	    mode = "uniform";
	 } else if (this->type->qualifier.flags.q.varying) {
	    mode = "varying";
	 } else if (this->type->qualifier.flags.q.in) {
	    mode = "in";
	    extra = " or in function parameter list";
	 } else if (this->type->qualifier.flags.q.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_shader_in) {
         var->read_only = true;

	 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."
             *
             * From page 33 (page 39 of the PDF) of the GLSL ES 3.00 spec:
             *
             *    "Vertex shader inputs can only be float, floating-point
             *    vectors, matrices, signed and unsigned integers and integer
             *    vectors. Vertex shader inputs cannot be 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->is_version(120, 300))
		  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 && var->type->is_array() &&
                !state->check_version(150, 0, &loc,
                                      "vertex shader input / attribute "
                                      "cannot have array type")) {
	       error_emitted = true;
	    }
	 } else if (state->target == geometry_shader) {
            /* From section 4.3.4 (Inputs) of the GLSL 1.50 spec:
             *
             *     Geometry shader input variables get the per-vertex values
             *     written out by vertex shader output variables of the same
             *     names. Since a geometry shader operates on a set of
             *     vertices, each input varying variable (or input block, see
             *     interface blocks below) needs to be declared as an array.
             */
            if (!var->type->is_array()) {
               _mesa_glsl_error(&loc, state,
                                "geometry shader inputs must be arrays");
            }

            handle_geometry_shader_input_decl(state, loc, var);
         }
      }

      /* Integer fragment inputs must be qualified with 'flat'.  In GLSL ES,
       * so must integer vertex outputs.
       *
       * From section 4.3.4 ("Inputs") of the GLSL 1.50 spec:
       *    "Fragment shader inputs that are signed or unsigned integers or
       *    integer vectors must be qualified with the interpolation qualifier
       *    flat."
       *
       * From section 4.3.4 ("Input Variables") of the GLSL 3.00 ES spec:
       *    "Fragment shader inputs that are, or contain, signed or unsigned
       *    integers or integer vectors must be qualified with the
       *    interpolation qualifier flat."
       *
       * From section 4.3.6 ("Output Variables") of the GLSL 3.00 ES spec:
       *    "Vertex shader outputs that are, or contain, signed or unsigned
       *    integers or integer vectors must be qualified with the
       *    interpolation qualifier flat."
       *
       * Note that prior to GLSL 1.50, this requirement applied to vertex
       * outputs rather than fragment inputs.  That creates problems in the
       * presence of geometry shaders, so we adopt the GLSL 1.50 rule for all
       * desktop GL shaders.  For GLSL ES shaders, we follow the spec and
       * apply the restriction to both vertex outputs and fragment inputs.
       *
       * Note also that the desktop GLSL specs are missing the text "or
       * contain"; this is presumably an oversight, since there is no
       * reasonable way to interpolate a fragment shader input that contains
       * an integer.
       */
      if (state->is_version(130, 300) &&
          var->type->contains_integer() &&
          var->interpolation != INTERP_QUALIFIER_FLAT &&
          ((state->target == fragment_shader && var->mode == ir_var_shader_in)
           || (state->target == vertex_shader && var->mode == ir_var_shader_out
               && state->es_shader))) {
         const char *var_type = (state->target == vertex_shader) ?
            "vertex output" : "fragment input";
         _mesa_glsl_error(&loc, state, "if a %s is (or contains) "
                          "an integer, then it must be qualified with 'flat'",
                          var_type);
      }


      /* Interpolation qualifiers cannot be applied to 'centroid' and
       * 'centroid varying'.
       *
       * From page 29 (page 35 of the PDF) of the GLSL 1.30 spec:
       *    "interpolation qualifiers may only precede the qualifiers in,
       *    centroid in, out, or centroid out in a declaration. They do not apply
       *    to the deprecated storage qualifiers varying or centroid varying."
       *
       * These deprecated storage qualifiers do not exist in GLSL ES 3.00.
       */
      if (state->is_version(130, 0)
          && this->type->qualifier.has_interpolation()
          && this->type->qualifier.flags.q.varying) {

         const char *i = this->type->qualifier.interpolation_string();
         assert(i != NULL);
         const char *s;
         if (this->type->qualifier.flags.q.centroid)
            s = "centroid varying";
         else
            s = "varying";

         _mesa_glsl_error(&loc, state,
                          "qualifier '%s' cannot be applied to the "
                          "deprecated storage qualifier '%s'", i, s);
      }


      /* Interpolation qualifiers can only apply to vertex shader outputs and
       * fragment shader inputs.
       *
       * From page 29 (page 35 of the PDF) of the GLSL 1.30 spec:
       *    "Outputs from a vertex shader (out) and inputs to a fragment
       *    shader (in) can be further qualified with one or more of these
       *    interpolation qualifiers"
       *
       * From page 31 (page 37 of the PDF) of the GLSL ES 3.00 spec:
       *    "These interpolation qualifiers may only precede the qualifiers
       *    in, centroid in, out, or centroid out in a declaration. They do
       *    not apply to inputs into a vertex shader or outputs from a
       *    fragment shader."
       */
      if (state->is_version(130, 300)
          && this->type->qualifier.has_interpolation()) {

         const char *i = this->type->qualifier.interpolation_string();
         assert(i != NULL);

         switch (state->target) {
         case vertex_shader:
            if (this->type->qualifier.flags.q.in) {
               _mesa_glsl_error(&loc, state,
                                "qualifier '%s' cannot be applied to vertex "
                                "shader inputs", i);
            }
            break;
         case fragment_shader:
            if (this->type->qualifier.flags.q.out) {
               _mesa_glsl_error(&loc, state,
                                "qualifier '%s' cannot be applied to fragment "
                                "shader outputs", i);
            }
            break;
         default:
            break;
         }
      }


      /* From section 4.3.4 of the GLSL 1.30 spec:
       *    "It is an error to use centroid in in a vertex shader."
       *
       * From section 4.3.4 of the GLSL ES 3.00 spec:
       *    "It is an error to use centroid in or interpolation qualifiers in
       *    a vertex shader input."
       */
      if (state->is_version(130, 300)
          && this->type->qualifier.flags.q.centroid
          && this->type->qualifier.flags.q.in
          && state->target == vertex_shader) {

         _mesa_glsl_error(&loc, state,
                          "'centroid in' cannot be used in a vertex shader");
      }

      /* Section 4.3.6 of the GLSL 1.30 specification states:
       * "It is an error to use centroid out in a fragment shader."
       *
       * The GL_ARB_shading_language_420pack extension specification states:
       * "It is an error to use auxiliary storage qualifiers or interpolation
       *  qualifiers on an output in a fragment shader."
       */
      if (state->target == fragment_shader &&
          this->type->qualifier.flags.q.out &&
          this->type->qualifier.has_auxiliary_storage()) {
         _mesa_glsl_error(&loc, state,
                          "auxiliary storage qualifiers cannot be used on "
                          "fragment shader outputs");
      }

      /* Precision qualifiers exists only in GLSL versions 1.00 and >= 1.30.
       */
      if (this->type->qualifier.precision != ast_precision_none) {
         state->check_precision_qualifiers_allowed(&loc);
      }


      /* Precision qualifiers apply to floating point, integer and sampler
       * types.
       *
       * Section 4.5.2 (Precision Qualifiers) of the GLSL 1.30 spec says:
       *    "Any floating point or any integer declaration can have the type
       *    preceded by one of these precision qualifiers [...] Literal
       *    constants do not have precision qualifiers. Neither do Boolean
       *    variables.
       *
       * Section 4.5 (Precision and Precision Qualifiers) of the GLSL 1.30
       * spec also says:
       *
       *     "Precision qualifiers are added for code portability with OpenGL
       *     ES, not for functionality. They have the same syntax as in OpenGL
       *     ES."
       *
       * Section 8 (Built-In Functions) of the GLSL ES 1.00 spec says:
       *
       *     "uniform lowp sampler2D sampler;
       *     highp vec2 coord;
       *     ...
       *     lowp vec4 col = texture2D (sampler, coord);
       *                                            // texture2D returns lowp"
       *
       * From this, we infer that GLSL 1.30 (and later) should allow precision
       * qualifiers on sampler types just like float and integer types.
       */
      if (this->type->qualifier.precision != ast_precision_none
          && !var->type->is_float()
          && !var->type->is_integer()
          && !var->type->is_record()
          && !var->type->is_sampler()
          && !(var->type->is_array()
               && (var->type->fields.array->is_float()
                   || var->type->fields.array->is_integer()))) {

         _mesa_glsl_error(&loc, state,
                          "precision qualifiers apply only to floating point"
                          ", integer and sampler types");
      }

      /* From page 17 (page 23 of the PDF) of the GLSL 1.20 spec:
       *
       *    "[Sampler types] can only be declared as function
       *    parameters or uniform variables (see Section 4.3.5
       *    "Uniform")".
       */
      if (var_type->contains_sampler() &&
          !this->type->qualifier.flags.q.uniform) {
         _mesa_glsl_error(&loc, state, "samplers must be declared uniform");
      }

      /* Process the initializer and add its instructions to a temporary
       * list.  This list will be added to the instruction stream (below) after
       * the declaration is added.  This is done because in some cases (such as
       * redeclarations) the declaration may not actually be added to the
       * instruction stream.
       */
      exec_list initializer_instructions;
      ir_variable *earlier =
         get_variable_being_redeclared(var, decl->get_location(), state,
                                       false /* allow_all_redeclarations */);
      if (earlier != NULL) {
         if (strncmp(var->name, "gl_", 3) == 0 &&
             earlier->how_declared == ir_var_declared_in_block) {
            _mesa_glsl_error(&loc, state,
                             "`%s' has already been redeclared using "
                             "gl_PerVertex", var->name);
         }
         earlier->how_declared = ir_var_declared_normally;
      }

      if (decl->initializer != NULL) {
	 result = process_initializer((earlier == NULL) ? var : earlier,
				      decl, this->type,
				      &initializer_instructions, state);
      }

      /* 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.flags.q.constant && decl->initializer == NULL) {
	 _mesa_glsl_error(& loc, state,
			  "const declaration of `%s' must be initialized",
			  decl->identifier);
      }

      if (state->es_shader) {
	 const glsl_type *const t = (earlier == NULL)
	    ? var->type : earlier->type;

         if (t->is_unsized_array())
            /* Section 10.17 of the GLSL ES 1.00 specification states that
             * unsized array declarations have been removed from the language.
             * Arrays that are sized using an initializer are still explicitly
             * sized.  However, GLSL ES 1.00 does not allow array
             * initializers.  That is only allowed in GLSL ES 3.00.
             *
             * Section 4.1.9 (Arrays) of the GLSL ES 3.00 spec says:
             *
             *     "An array type can also be formed without specifying a size
             *     if the definition includes an initializer:
             *
             *         float x[] = float[2] (1.0, 2.0);     // declares an array of size 2
             *         float y[] = float[] (1.0, 2.0, 3.0); // declares an array of size 3
             *
             *         float a[5];
             *         float b[] = a;"
             */
            _mesa_glsl_error(& loc, state,
                             "unsized array declarations are not allowed in "
                             "GLSL ES");
      }

      /* If the declaration is not a redeclaration, there are a few additional
       * semantic checks that must be applied.  In addition, variable that was
       * created for the declaration should be added to the IR stream.
       */
      if (earlier == NULL) {
         validate_identifier(decl->identifier, loc, state);

	 /* Add the variable to the symbol table.  Note that the initializer's
	  * IR was already processed earlier (though it hasn't been emitted
	  * yet), without the variable in scope.
	  *
	  * 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."
	  */
	 if (!state->symbols->add_variable(var)) {
	    YYLTYPE loc = this->get_location();
	    _mesa_glsl_error(&loc, state, "name `%s' already taken in the "
			     "current scope", decl->identifier);
	    continue;
	 }

	 /* Push the variable declaration to the top.  It means that all the
	  * variable declarations will appear in a funny last-to-first order,
	  * but otherwise we run into trouble if a function is prototyped, a
	  * global var is decled, then the function is defined with usage of
	  * the global var.  See glslparsertest's CorrectModule.frag.
	  */
	 instructions->push_head(var);
      }

      instructions->append_list(&initializer_instructions);
   }


   /* 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->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;
   }

   /* This only handles "vec4 foo[..]".  The earlier specifier->glsl_type(...)
    * call already handled the "vec4[..] foo" case.
    */
   if (this->is_array) {
      type = process_array_type(&loc, type, this->array_size, state);
   }

   if (!type->is_error() && type->is_unsized_array()) {
      _mesa_glsl_error(&loc, state, "arrays passed as parameters must have "
		       "a declared size");
      type = glsl_type::error_type;
   }

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

   /* 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,
				    true);

   /* From page 17 (page 23 of the PDF) of the GLSL 1.20 spec:
    *
    *    "Samplers cannot be treated as l-values; hence cannot be used
    *    as out or inout function parameters, nor can they be assigned
    *    into."
    */
   if ((var->mode == ir_var_function_inout || var->mode == ir_var_function_out)
       && type->contains_sampler()) {
      _mesa_glsl_error(&loc, state, "out and inout parameters cannot contain samplers");
      type = glsl_type::error_type;
   }

   /* From page 39 (page 45 of the PDF) of the GLSL 1.10 spec:
    *
    *    "When calling a function, expressions that do not evaluate to
    *     l-values cannot be passed to parameters declared as out or inout."
    *
    * From page 32 (page 38 of the PDF) of the GLSL 1.10 spec:
    *
    *    "Other binary or unary expressions, non-dereferenced arrays,
    *     function names, swizzles with repeated fields, and constants
    *     cannot be l-values."
    *
    * So for GLSL 1.10, passing an array as an out or inout parameter is not
    * allowed.  This restriction is removed in GLSL 1.20, and in GLSL ES.
    */
   if ((var->mode == ir_var_function_inout || var->mode == ir_var_function_out)
       && type->is_array()
       && !state->check_version(120, 100, &loc,
                                "arrays cannot be out or inout parameters")) {
      type = glsl_type::error_type;
   }

   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");
   }
}


void
emit_function(_mesa_glsl_parse_state *state, ir_function *f)
{
   /* IR invariants disallow function declarations or definitions
    * nested within other function definitions.  But there is no
    * requirement about the relative order of function declarations
    * and definitions with respect to one another.  So simply insert
    * the new ir_function block at the end of the toplevel instruction
    * list.
    */
   state->toplevel_ir->push_tail(f);
}


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;

   /* New functions are always added to the top-level IR instruction stream,
    * so this instruction list pointer is ignored.  See also emit_function
    * (called below).
    */
   (void) instructions;

   /* From page 21 (page 27 of the PDF) of the GLSL 1.20 spec,
    *
    *   "Function declarations (prototypes) cannot occur inside of functions;
    *   they must be at global scope, or for the built-in functions, outside
    *   the global scope."
    *
    * From page 27 (page 33 of the PDF) of the GLSL ES 1.00.16 spec,
    *
    *   "User defined functions may only be defined within the global scope."
    *
    * Note that this language does not appear in GLSL 1.10.
    */
   if ((state->current_function != NULL) &&
       state->is_version(120, 100)) {
      YYLTYPE loc = this->get_location();
      _mesa_glsl_error(&loc, state,
		       "declaration of function `%s' not allowed within "
		       "function body", name);
   }

   validate_identifier(name, this->get_location(), state);

   /* 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->glsl_type(& return_type_name, state);

   if (!return_type) {
      YYLTYPE loc = this->get_location();
      _mesa_glsl_error(&loc, state,
		       "function `%s' has undeclared return type `%s'",
		       name, return_type_name);
      return_type = glsl_type::error_type;
   }

   /* 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);
   }

   /* Section 6.1 (Function Definitions) of the GLSL 1.20 spec says:
    *
    *     "Arrays are allowed as arguments and as the return type. In both
    *     cases, the array must be explicitly sized."
    */
   if (return_type->is_unsized_array()) {
      YYLTYPE loc = this->get_location();
      _mesa_glsl_error(& loc, state,
		       "function `%s' return type array must be explicitly "
		       "sized", name);
   }

   /* From page 17 (page 23 of the PDF) of the GLSL 1.20 spec:
    *
    *    "[Sampler types] can only be declared as function parameters
    *    or uniform variables (see Section 4.3.5 "Uniform")".
    */
   if (return_type->contains_sampler()) {
      YYLTYPE loc = this->get_location();
      _mesa_glsl_error(&loc, state,
                       "function `%s' return type can't contain a sampler",
                       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 && (state->es_shader || f->has_user_signature())) {
      sig = f->exact_matching_signature(state, &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 (sig->is_defined) {
            if (is_definition) {
               YYLTYPE loc = this->get_location();
               _mesa_glsl_error(& loc, state, "function `%s' redefined", name);
            } else {
               /* We just encountered a prototype that exactly matches a
                * function that's already been defined.  This is redundant,
                * and we should ignore it.
                */
               return NULL;
            }
	 }
      }
   } else {
      f = new(ctx) ir_function(name);
      if (!state->symbols->add_function(f)) {
	 /* 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);
	 return NULL;
      }

      emit_function(state, 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;
   if (signature == NULL)
      return NULL;

   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);
      }
   }

   /* 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) {
	 ir_rvalue *ret = opt_return_value->hir(instructions, state);

	 /* The value of the return type can be NULL if the shader says
	  * 'return foo();' and foo() is a function that returns void.
	  *
	  * NOTE: The GLSL spec doesn't say that this is an error.  The type
	  * of the return value is void.  If the return type of the function is
	  * also void, then this should compile without error.  Seriously.
	  */
	 const glsl_type *const ret_type =
	    (ret == NULL) ? glsl_type::void_type : ret->type;

         /* Implicit conversions are not allowed for return values prior to
          * ARB_shading_language_420pack.
          */
         if (state->current_function->return_type != ret_type) {
	    YYLTYPE loc = this->get_location();

            if (state->ARB_shading_language_420pack_enable) {
               if (!apply_implicit_conversion(state->current_function->return_type,
                                              ret, state)) {
                  _mesa_glsl_error(& loc, state,
                                   "could not implicitly convert return value "
                                   "to %s, in function `%s'",
                                   state->current_function->return_type->name,
                                   state->current_function->function_name());
               }
            } else {
               _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);
            }
         } else if (state->current_function->return_type->base_type ==
                    GLSL_TYPE_VOID) {
            YYLTYPE loc = this->get_location();

            /* The ARB_shading_language_420pack, GLSL ES 3.0, and GLSL 4.20
             * specs add a clarification:
             *
             *    "A void function can only use return without a return argument, even if
             *     the return argument has void type. Return statements only accept values:
             *
             *         void func1() { }
             *         void func2() { return func1(); } // illegal return statement"
             */
            _mesa_glsl_error(& loc, state,
                             "void functions can only use `return' without a "
                             "return argument");
         }

	 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:
      if (mode == ast_continue &&
	  state->loop_nesting_ast == NULL) {
	 YYLTYPE loc = this->get_location();

	 _mesa_glsl_error(& loc, state,
			  "continue may only appear in a loop");
      } else if (mode == ast_break &&
		 state->loop_nesting_ast == NULL &&
		 state->switch_state.switch_nesting_ast == NULL) {
	 YYLTYPE loc = this->get_location();

	 _mesa_glsl_error(& loc, state,
			  "break may only appear in a loop or a switch");
      } else {
	 /* For a loop, inline the for loop expression again,
	  * since we don't know where near the end of
	  * the loop body the normal copy of it
	  * is going to be placed.
	  */
	 if (state->loop_nesting_ast != NULL &&
	     mode == ast_continue &&
	     state->loop_nesting_ast->rest_expression) {
	    state->loop_nesting_ast->rest_expression->hir(instructions,
							  state);
	 }

	 if (state->switch_state.is_switch_innermost &&
	     mode == ast_break) {
	    /* Force break out of switch by setting is_break switch state.
	     */
	    ir_variable *const is_break_var = state->switch_state.is_break_var;
	    ir_dereference_variable *const deref_is_break_var =
	       new(ctx) ir_dereference_variable(is_break_var);
	    ir_constant *const true_val = new(ctx) ir_constant(true);
	    ir_assignment *const set_break_var =
	       new(ctx) ir_assignment(deref_is_break_var, true_val);
	    
	    instructions->push_tail(set_break_var);
	 }
	 else {
	    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) {
      state->symbols->push_scope();
      then_statement->hir(& stmt->then_instructions, state);
      state->symbols->pop_scope();
   }

   if (else_statement != NULL) {
      state->symbols->push_scope();
      else_statement->hir(& stmt->else_instructions, state);
      state->symbols->pop_scope();
   }

   instructions->push_tail(stmt);

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


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

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

   /* From page 66 (page 55 of the PDF) of the GLSL 1.50 spec:
    *
    *    "The type of init-expression in a switch statement must be a 
    *     scalar integer." 
    */
   if (!test_expression->type->is_scalar() ||
       !test_expression->type->is_integer()) {
      YYLTYPE loc = this->test_expression->get_location();

      _mesa_glsl_error(& loc,
		       state,
		       "switch-statement expression must be scalar "
		       "integer");
   }

   /* Track the switch-statement nesting in a stack-like manner.
    */
   struct glsl_switch_state saved = state->switch_state;

   state->switch_state.is_switch_innermost = true;
   state->switch_state.switch_nesting_ast = this;
   state->switch_state.labels_ht = hash_table_ctor(0, hash_table_pointer_hash,
						   hash_table_pointer_compare);
   state->switch_state.previous_default = NULL;

   /* Initalize is_fallthru state to false.
    */
   ir_rvalue *const is_fallthru_val = new (ctx) ir_constant(false);
   state->switch_state.is_fallthru_var =
      new(ctx) ir_variable(glsl_type::bool_type,
			   "switch_is_fallthru_tmp",
			   ir_var_temporary);
   instructions->push_tail(state->switch_state.is_fallthru_var);

   ir_dereference_variable *deref_is_fallthru_var =
      new(ctx) ir_dereference_variable(state->switch_state.is_fallthru_var);
   instructions->push_tail(new(ctx) ir_assignment(deref_is_fallthru_var,
						  is_fallthru_val));

   /* Initalize is_break state to false.
    */
   ir_rvalue *const is_break_val = new (ctx) ir_constant(false);
   state->switch_state.is_break_var = new(ctx) ir_variable(glsl_type::bool_type,
							   "switch_is_break_tmp",
							   ir_var_temporary);
   instructions->push_tail(state->switch_state.is_break_var);

   ir_dereference_variable *deref_is_break_var =
      new(ctx) ir_dereference_variable(state->switch_state.is_break_var);
   instructions->push_tail(new(ctx) ir_assignment(deref_is_break_var,
						  is_break_val));

   /* Cache test expression.
    */
   test_to_hir(instructions, state);

   /* Emit code for body of switch stmt.
    */
   body->hir(instructions, state);

   hash_table_dtor(state->switch_state.labels_ht);

   state->switch_state = saved;

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


void
ast_switch_statement::test_to_hir(exec_list *instructions,
				  struct _mesa_glsl_parse_state *state)
{
   void *ctx = state;

   /* Cache value of test expression. */
   ir_rvalue *const test_val =
      test_expression->hir(instructions,
			   state);

   state->switch_state.test_var = new(ctx) ir_variable(test_val->type,
						       "switch_test_tmp",
						       ir_var_temporary);
   ir_dereference_variable *deref_test_var =
      new(ctx) ir_dereference_variable(state->switch_state.test_var);

   instructions->push_tail(state->switch_state.test_var);
   instructions->push_tail(new(ctx) ir_assignment(deref_test_var, test_val));
}


ir_rvalue *
ast_switch_body::hir(exec_list *instructions,
		     struct _mesa_glsl_parse_state *state)
{
   if (stmts != NULL)
      stmts->hir(instructions, state);

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

ir_rvalue *
ast_case_statement_list::hir(exec_list *instructions,
			     struct _mesa_glsl_parse_state *state)
{
   foreach_list_typed (ast_case_statement, case_stmt, link, & this->cases)
      case_stmt->hir(instructions, state);

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

ir_rvalue *
ast_case_statement::hir(exec_list *instructions,
			struct _mesa_glsl_parse_state *state)
{
   labels->hir(instructions, state);

   /* Conditionally set fallthru state based on break state. */
   ir_constant *const false_val = new(state) ir_constant(false);
   ir_dereference_variable *const deref_is_fallthru_var =
      new(state) ir_dereference_variable(state->switch_state.is_fallthru_var);
   ir_dereference_variable *const deref_is_break_var =
      new(state) ir_dereference_variable(state->switch_state.is_break_var);
   ir_assignment *const reset_fallthru_on_break =
      new(state) ir_assignment(deref_is_fallthru_var,
			       false_val,
			       deref_is_break_var);
   instructions->push_tail(reset_fallthru_on_break);

   /* Guard case statements depending on fallthru state. */
   ir_dereference_variable *const deref_fallthru_guard =
      new(state) ir_dereference_variable(state->switch_state.is_fallthru_var);
   ir_if *const test_fallthru = new(state) ir_if(deref_fallthru_guard);

   foreach_list_typed (ast_node, stmt, link, & this->stmts)
      stmt->hir(& test_fallthru->then_instructions, state);

   instructions->push_tail(test_fallthru);

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


ir_rvalue *
ast_case_label_list::hir(exec_list *instructions,
			 struct _mesa_glsl_parse_state *state)
{
   foreach_list_typed (ast_case_label, label, link, & this->labels)
      label->hir(instructions, state);

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

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

   ir_dereference_variable *deref_fallthru_var =
      new(ctx) ir_dereference_variable(state->switch_state.is_fallthru_var);

   ir_rvalue *const true_val = new(ctx) ir_constant(true);

   /* If not default case, ... */
   if (this->test_value != NULL) {
      /* Conditionally set fallthru state based on
       * comparison of cached test expression value to case label.
       */
      ir_rvalue *const label_rval = this->test_value->hir(instructions, state);
      ir_constant *label_const = label_rval->constant_expression_value();

      if (!label_const) {
	 YYLTYPE loc = this->test_value->get_location();

	 _mesa_glsl_error(& loc, state,
			  "switch statement case label must be a "
			  "constant expression");

	 /* Stuff a dummy value in to allow processing to continue. */
	 label_const = new(ctx) ir_constant(0);
      } else {
	 ast_expression *previous_label = (ast_expression *)
	    hash_table_find(state->switch_state.labels_ht,
			    (void *)(uintptr_t)label_const->value.u[0]);

	 if (previous_label) {
	    YYLTYPE loc = this->test_value->get_location();
	    _mesa_glsl_error(& loc, state,
			     "duplicate case value");

	    loc = previous_label->get_location();
	    _mesa_glsl_error(& loc, state,
			     "this is the previous case label");
	 } else {
	    hash_table_insert(state->switch_state.labels_ht,
			      this->test_value,
			      (void *)(uintptr_t)label_const->value.u[0]);
	 }
      }

      ir_dereference_variable *deref_test_var =
	 new(ctx) ir_dereference_variable(state->switch_state.test_var);

      ir_rvalue *const test_cond = new(ctx) ir_expression(ir_binop_all_equal,
							  label_const,
							  deref_test_var);

      ir_assignment *set_fallthru_on_test =
	 new(ctx) ir_assignment(deref_fallthru_var,
				true_val,
				test_cond);

      instructions->push_tail(set_fallthru_on_test);
   } else { /* default case */
      if (state->switch_state.previous_default) {
	 YYLTYPE loc = this->get_location();
	 _mesa_glsl_error(& loc, state,
			  "multiple default labels in one switch");

	 loc = state->switch_state.previous_default->get_location();
	 _mesa_glsl_error(& loc, state,
			  "this is the first default label");
      }
      state->switch_state.previous_default = this;

      /* Set falltrhu state. */
      ir_assignment *set_fallthru =
	 new(ctx) ir_assignment(deref_fallthru_var, true_val);

      instructions->push_tail(set_fallthru);
   }

   /* Case 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, cond);

	 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 nesting. */
   ast_iteration_statement *nesting_ast = state->loop_nesting_ast;

   state->loop_nesting_ast = this;

   /* Likewise, indicate that following code is closest to a loop,
    * NOT closest to a switch.
    */
   bool saved_is_switch_innermost = state->switch_state.is_switch_innermost;
   state->switch_state.is_switch_innermost = false;

   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_nesting_ast = nesting_ast;
   state->switch_state.is_switch_innermost = saved_is_switch_innermost;

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


/**
 * Determine if the given type is valid for establishing a default precision
 * qualifier.
 *
 * From GLSL ES 3.00 section 4.5.4 ("Default Precision Qualifiers"):
 *
 *     "The precision statement
 *
 *         precision precision-qualifier type;
 *
 *     can be used to establish a default precision qualifier. The type field
 *     can be either int or float or any of the sampler types, and the
 *     precision-qualifier can be lowp, mediump, or highp."
 *
 * GLSL ES 1.00 has similar language.  GLSL 1.30 doesn't allow precision
 * qualifiers on sampler types, but this seems like an oversight (since the
 * intention of including these in GLSL 1.30 is to allow compatibility with ES
 * shaders).  So we allow int, float, and all sampler types regardless of GLSL
 * version.
 */
static bool
is_valid_default_precision_type(const struct glsl_type *const type)
{
   if (type == NULL)
      return false;

   switch (type->base_type) {
   case GLSL_TYPE_INT:
   case GLSL_TYPE_FLOAT:
      /* "int" and "float" are valid, but vectors and matrices are not. */
      return type->vector_elements == 1 && type->matrix_columns == 1;
   case GLSL_TYPE_SAMPLER:
      return true;
   default:
      return false;
   }
}


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

   YYLTYPE loc = this->get_location();

   /* If this is a precision statement, check that the type to which it is
    * applied is either float or int.
    *
    * From section 4.5.3 of the GLSL 1.30 spec:
    *    "The precision statement
    *       precision precision-qualifier type;
    *    can be used to establish a default precision qualifier. The type
    *    field can be either int or float [...].  Any other types or
    *    qualifiers will result in an error.
    */
   if (this->default_precision != ast_precision_none) {
      if (!state->check_precision_qualifiers_allowed(&loc))
         return NULL;

      if (this->structure != NULL) {
         _mesa_glsl_error(&loc, state,
                          "precision qualifiers do not apply to structures");
         return NULL;
      }

      if (this->is_array) {
         _mesa_glsl_error(&loc, state,
                          "default precision statements do not apply to "
                          "arrays");
         return NULL;
      }

      const struct glsl_type *const type =
         state->symbols->get_type(this->type_name);
      if (!is_valid_default_precision_type(type)) {
         _mesa_glsl_error(&loc, state,
                          "default precision statements apply only to "
                          "float, int, and sampler types");
         return NULL;
      }

      if (type->base_type == GLSL_TYPE_FLOAT
          && state->es_shader
          && state->target == fragment_shader) {
         /* Section 4.5.3 (Default Precision Qualifiers) of the GLSL ES 1.00
          * spec says:
          *
          *     "The fragment language has no default precision qualifier for
          *     floating point types."
          *
          * As a result, we have to track whether or not default precision has
          * been specified for float in GLSL ES fragment shaders.
          *
          * Earlier in that same section, the spec says:
          *
          *     "Non-precision qualified declarations will use the precision
          *     qualifier specified in the most recent precision statement
          *     that is still in scope. The precision statement has the same
          *     scoping rules as variable declarations. If it is declared
          *     inside a compound statement, its effect stops at the end of
          *     the innermost statement it was declared in. Precision
          *     statements in nested scopes override precision statements in
          *     outer scopes. Multiple precision statements for the same basic
          *     type can appear inside the same scope, with later statements
          *     overriding earlier statements within that scope."
          *
          * Default precision specifications follow the same scope rules as
          * variables.  So, we can track the state of the default float
          * precision in the symbol table, and the rules will just work.  This
          * is a slight abuse of the symbol table, but it has the semantics
          * that we want.
          */
         ir_variable *const junk =
            new(state) ir_variable(type, "#default precision",
                                   ir_var_temporary);

         state->symbols->add_variable(junk);
      }

      /* FINISHME: Translate precision statements into IR. */
      return NULL;
   }

   /* _mesa_ast_set_aggregate_type() sets the <structure> field so that
    * process_record_constructor() can do type-checking on C-style initializer
    * expressions of structs, but ast_struct_specifier should only be translated
    * to HIR if it is declaring the type of a structure.
    *
    * The ->is_declaration field is false for initializers of variables
    * declared separately from the struct's type definition.
    *
    *    struct S { ... };              (is_declaration = true)
    *    struct T { ... } t = { ... };  (is_declaration = true)
    *    S s = { ... };                 (is_declaration = false)
    */
   if (this->structure != NULL && this->structure->is_declaration)
      return this->structure->hir(instructions, state);

   return NULL;
}


/**
 * Process a structure or interface block tree into an array of structure fields
 *
 * After parsing, where there are some syntax differnces, structures and
 * interface blocks are almost identical.  They are similar enough that the
 * AST for each can be processed the same way into a set of
 * \c glsl_struct_field to describe the members.
 *
 * If we're processing an interface block, var_mode should be the type of the
 * interface block (ir_var_shader_in, ir_var_shader_out, or ir_var_uniform).
 * If we're processing a structure, var_mode should be ir_var_auto.
 *
 * \return
 * The number of fields processed.  A pointer to the array structure fields is
 * stored in \c *fields_ret.
 */
unsigned
ast_process_structure_or_interface_block(exec_list *instructions,
					 struct _mesa_glsl_parse_state *state,
					 exec_list *declarations,
					 YYLTYPE &loc,
					 glsl_struct_field **fields_ret,
                                         bool is_interface,
                                         bool block_row_major,
                                         bool allow_reserved_names,
                                         ir_variable_mode var_mode)
{
   unsigned decl_count = 0;

   /* Make an initial pass over the list of 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, declarations) {
      foreach_list_const (decl_ptr, & decl_list->declarations) {
	 decl_count++;
      }
   }

   /* Allocate storage for the 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 or in interface blocks are processed.
    */
   glsl_struct_field *const fields = ralloc_array(state, glsl_struct_field,
						  decl_count);

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

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

      /* Section 10.9 of the GLSL ES 1.00 specification states that
       * embedded structure definitions have been removed from the language.
       */
      if (state->es_shader && decl_list->type->specifier->structure != NULL) {
	 _mesa_glsl_error(&loc, state, "embedded structure definitions are "
			  "not allowed in GLSL ES 1.00");
      }

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

      foreach_list_typed (ast_declaration, decl, link,
			  &decl_list->declarations) {
         if (!allow_reserved_names)
            validate_identifier(decl->identifier, loc, state);

         /* From the GL_ARB_uniform_buffer_object spec:
          *
          *     "Sampler types are not allowed inside of uniform
          *      blocks. All other types, arrays, and structures
          *      allowed for uniforms are allowed within a uniform
          *      block."
          *
          * It should be impossible for decl_type to be NULL here.  Cases that
          * might naturally lead to decl_type being NULL, especially for the
          * is_interface case, will have resulted in compilation having
          * already halted due to a syntax error.
          */
         const struct glsl_type *field_type =
            decl_type != NULL ? decl_type : glsl_type::error_type;

         if (is_interface && field_type->contains_sampler()) {
            YYLTYPE loc = decl_list->get_location();
            _mesa_glsl_error(&loc, state,
                             "uniform in non-default uniform block contains sampler");
         }

         if (field_type->contains_atomic()) {
            /* FINISHME: Add a spec quotation here once updated spec
             * FINISHME: language is available.  See Khronos bug #10903
             * FINISHME: on whether atomic counters are allowed in
             * FINISHME: structures.
             */
            YYLTYPE loc = decl_list->get_location();
            _mesa_glsl_error(&loc, state, "atomic counter in structure or "
                             "uniform block");
         }

         const struct ast_type_qualifier *const qual =
            & decl_list->type->qualifier;
         if (qual->flags.q.std140 ||
             qual->flags.q.packed ||
             qual->flags.q.shared) {
            _mesa_glsl_error(&loc, state,
                             "uniform block layout qualifiers std140, packed, and "
                             "shared can only be applied to uniform blocks, not "
                             "members");
         }

	 if (decl->is_array) {
	    field_type = process_array_type(&loc, decl_type, decl->array_size,
					    state);
	 }
         fields[i].type = field_type;
	 fields[i].name = decl->identifier;
         fields[i].location = -1;
         fields[i].interpolation =
            interpret_interpolation_qualifier(qual, var_mode, state, &loc);
         fields[i].centroid = qual->flags.q.centroid ? 1 : 0;

         if (qual->flags.q.row_major || qual->flags.q.column_major) {
            if (!qual->flags.q.uniform) {
               _mesa_glsl_error(&loc, state,
                                "row_major and column_major can only be "
                                "applied to uniform interface blocks");
            } else
               validate_matrix_layout_for_type(state, &loc, field_type, NULL);
         }

         if (qual->flags.q.uniform && qual->has_interpolation()) {
            _mesa_glsl_error(&loc, state,
                             "interpolation qualifiers cannot be used "
                             "with uniform interface blocks");
         }

         if (field_type->is_matrix() ||
             (field_type->is_array() && field_type->fields.array->is_matrix())) {
            fields[i].row_major = block_row_major;
            if (qual->flags.q.row_major)
               fields[i].row_major = true;
            else if (qual->flags.q.column_major)
               fields[i].row_major = false;
         }

	 i++;
      }
   }

   assert(i == decl_count);

   *fields_ret = fields;
   return decl_count;
}


ir_rvalue *
ast_struct_specifier::hir(exec_list *instructions,
			  struct _mesa_glsl_parse_state *state)
{
   YYLTYPE loc = this->get_location();

   /* Section 4.1.8 (Structures) of the GLSL 1.10 spec says:
    *
    *     "Anonymous structures are not supported; so embedded structures must
    *     have a declarator. A name given to an embedded struct is scoped at
    *     the same level as the struct it is embedded in."
    *
    * The same section of the  GLSL 1.20 spec says:
    *
    *     "Anonymous structures are not supported. Embedded structures are not
    *     supported.
    *
    *         struct S { float f; };
    *         struct T {
    *             S;              // Error: anonymous structures disallowed
    *             struct { ... }; // Error: embedded structures disallowed
    *             S s;            // Okay: nested structures with name are allowed
    *         };"
    *
    * The GLSL ES 1.00 and 3.00 specs have similar langauge and examples.  So,
    * we allow embedded structures in 1.10 only.
    */
   if (state->language_version != 110 && state->struct_specifier_depth != 0)
      _mesa_glsl_error(&loc, state,
		       "embedded structure declartions are not allowed");

   state->struct_specifier_depth++;

   glsl_struct_field *fields;
   unsigned decl_count =
      ast_process_structure_or_interface_block(instructions,
					       state,
					       &this->declarations,
					       loc,
					       &fields,
                                               false,
                                               false,
                                               false /* allow_reserved_names */,
                                               ir_var_auto);

   validate_identifier(this->name, loc, state);

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

   if (!state->symbols->add_type(name, t)) {
      _mesa_glsl_error(& loc, state, "struct `%s' previously defined", name);
   } else {
      const glsl_type **s = reralloc(state, state->user_structures,
				     const glsl_type *,
				     state->num_user_structures + 1);
      if (s != NULL) {
	 s[state->num_user_structures] = t;
	 state->user_structures = s;
	 state->num_user_structures++;
      }
   }

   state->struct_specifier_depth--;

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


/**
 * Visitor class which detects whether a given interface block has been used.
 */
class interface_block_usage_visitor : public ir_hierarchical_visitor
{
public:
   interface_block_usage_visitor(ir_variable_mode mode, const glsl_type *block)
      : mode(mode), block(block), found(false)
   {
   }

   virtual ir_visitor_status visit(ir_dereference_variable *ir)
   {
      if (ir->var->mode == mode && ir->var->get_interface_type() == block) {
         found = true;
         return visit_stop;
      }
      return visit_continue;
   }

   bool usage_found() const
   {
      return this->found;
   }

private:
   ir_variable_mode mode;
   const glsl_type *block;
   bool found;
};


ir_rvalue *
ast_interface_block::hir(exec_list *instructions,
		          struct _mesa_glsl_parse_state *state)
{
   YYLTYPE loc = this->get_location();

   /* The ast_interface_block has a list of ast_declarator_lists.  We
    * need to turn those into ir_variables with an association
    * with this uniform block.
    */
   enum glsl_interface_packing packing;
   if (this->layout.flags.q.shared) {
      packing = GLSL_INTERFACE_PACKING_SHARED;
   } else if (this->layout.flags.q.packed) {
      packing = GLSL_INTERFACE_PACKING_PACKED;
   } else {
      /* The default layout is std140.
       */
      packing = GLSL_INTERFACE_PACKING_STD140;
   }

   ir_variable_mode var_mode;
   const char *iface_type_name;
   if (this->layout.flags.q.in) {
      var_mode = ir_var_shader_in;
      iface_type_name = "in";
   } else if (this->layout.flags.q.out) {
      var_mode = ir_var_shader_out;
      iface_type_name = "out";
   } else if (this->layout.flags.q.uniform) {
      var_mode = ir_var_uniform;
      iface_type_name = "uniform";
   } else {
      var_mode = ir_var_auto;
      iface_type_name = "UNKNOWN";
      assert(!"interface block layout qualifier not found!");
   }

   bool redeclaring_per_vertex = strcmp(this->block_name, "gl_PerVertex") == 0;
   bool block_row_major = this->layout.flags.q.row_major;
   exec_list declared_variables;
   glsl_struct_field *fields;
   unsigned int num_variables =
      ast_process_structure_or_interface_block(&declared_variables,
                                               state,
                                               &this->declarations,
                                               loc,
                                               &fields,
                                               true,
                                               block_row_major,
                                               redeclaring_per_vertex,
                                               var_mode);

   if (!redeclaring_per_vertex)
      validate_identifier(this->block_name, loc, state);

   const glsl_type *earlier_per_vertex = NULL;
   if (redeclaring_per_vertex) {
      /* Find the previous declaration of gl_PerVertex.  If we're redeclaring
       * the named interface block gl_in, we can find it by looking at the
       * previous declaration of gl_in.  Otherwise we can find it by looking
       * at the previous decalartion of any of the built-in outputs,
       * e.g. gl_Position.
       *
       * Also check that the instance name and array-ness of the redeclaration
       * are correct.
       */
      switch (var_mode) {
      case ir_var_shader_in:
         if (ir_variable *earlier_gl_in =
             state->symbols->get_variable("gl_in")) {
            earlier_per_vertex = earlier_gl_in->get_interface_type();
         } else {
            _mesa_glsl_error(&loc, state,
                             "redeclaration of gl_PerVertex input not allowed "
                             "in the %s shader",
                             _mesa_glsl_shader_target_name(state->target));
         }
         if (this->instance_name == NULL ||
             strcmp(this->instance_name, "gl_in") != 0 || !this->is_array) {
            _mesa_glsl_error(&loc, state,
                             "gl_PerVertex input must be redeclared as "
                             "gl_in[]");
         }
         break;
      case ir_var_shader_out:
         if (ir_variable *earlier_gl_Position =
             state->symbols->get_variable("gl_Position")) {
            earlier_per_vertex = earlier_gl_Position->get_interface_type();
         } else {
            _mesa_glsl_error(&loc, state,
                             "redeclaration of gl_PerVertex output not "
                             "allowed in the %s shader",
                             _mesa_glsl_shader_target_name(state->target));
         }
         if (this->instance_name != NULL) {
            _mesa_glsl_error(&loc, state,
                             "gl_PerVertex input may not be redeclared with "
                             "an instance name");
         }
         break;
      default:
         _mesa_glsl_error(&loc, state,
                          "gl_PerVertex must be declared as an input or an "
                          "output");
         break;
      }

      if (earlier_per_vertex == NULL) {
         /* An error has already been reported.  Bail out to avoid null
          * dereferences later in this function.
          */
         return NULL;
      }

      /* Copy locations from the old gl_PerVertex interface block. */
      for (unsigned i = 0; i < num_variables; i++) {
         int j = earlier_per_vertex->field_index(fields[i].name);
         if (j == -1) {
            _mesa_glsl_error(&loc, state,
                             "redeclaration of gl_PerVertex must be a subset "
                             "of the built-in members of gl_PerVertex");
         } else {
            fields[i].location =
               earlier_per_vertex->fields.structure[j].location;
            fields[i].interpolation =
               earlier_per_vertex->fields.structure[j].interpolation;
            fields[i].centroid =
               earlier_per_vertex->fields.structure[j].centroid;
         }
      }

      /* From section 7.1 ("Built-in Language Variables") of the GLSL 4.10
       * spec:
       *
       *     If a built-in interface block is redeclared, it must appear in
       *     the shader before any use of any member included in the built-in
       *     declaration, or a compilation error will result.
       *
       * This appears to be a clarification to the behaviour established for
       * gl_PerVertex by GLSL 1.50, therefore we implement this behaviour
       * regardless of GLSL version.
       */
      interface_block_usage_visitor v(var_mode, earlier_per_vertex);
      v.run(instructions);
      if (v.usage_found()) {
         _mesa_glsl_error(&loc, state,
                          "redeclaration of a built-in interface block must "
                          "appear before any use of any member of the "
                          "interface block");
      }
   }

   const glsl_type *block_type =
      glsl_type::get_interface_instance(fields,
                                        num_variables,
                                        packing,
                                        this->block_name);

   if (!state->symbols->add_interface(block_type->name, block_type, var_mode)) {
      YYLTYPE loc = this->get_location();
      _mesa_glsl_error(&loc, state, "interface block `%s' with type `%s' "
                       "already taken in the current scope",
                       this->block_name, iface_type_name);
   }

   /* Since interface blocks cannot contain statements, it should be
    * impossible for the block to generate any instructions.
    */
   assert(declared_variables.is_empty());

   /* From section 4.3.4 (Inputs) of the GLSL 1.50 spec:
    *
    *     Geometry shader input variables get the per-vertex values written
    *     out by vertex shader output variables of the same names. Since a
    *     geometry shader operates on a set of vertices, each input varying
    *     variable (or input block, see interface blocks below) needs to be
    *     declared as an array.
    */
   if (state->target == geometry_shader && !this->is_array &&
       var_mode == ir_var_shader_in) {
      _mesa_glsl_error(&loc, state, "geometry shader inputs must be arrays");
   }

   /* Page 39 (page 45 of the PDF) of section 4.3.7 in the GLSL ES 3.00 spec
    * says:
    *
    *     "If an instance name (instance-name) is used, then it puts all the
    *     members inside a scope within its own name space, accessed with the
    *     field selector ( . ) operator (analogously to structures)."
    */
   if (this->instance_name) {
      if (redeclaring_per_vertex) {
         /* When a built-in in an unnamed interface block is redeclared,
          * get_variable_being_redeclared() calls
          * check_builtin_array_max_size() to make sure that built-in array
          * variables aren't redeclared to illegal sizes.  But we're looking
          * at a redeclaration of a named built-in interface block.  So we
          * have to manually call check_builtin_array_max_size() for all parts
          * of the interface that are arrays.
          */
         for (unsigned i = 0; i < num_variables; i++) {
            if (fields[i].type->is_array()) {
               const unsigned size = fields[i].type->array_size();
               check_builtin_array_max_size(fields[i].name, size, loc, state);
            }
         }
      } else {
         validate_identifier(this->instance_name, loc, state);
      }

      ir_variable *var;

      if (this->is_array) {
         /* Section 4.3.7 (Interface Blocks) of the GLSL 1.50 spec says:
          *
          *     For uniform blocks declared an array, each individual array
          *     element corresponds to a separate buffer object backing one
          *     instance of the block. As the array size indicates the number
          *     of buffer objects needed, uniform block array declarations
          *     must specify an array size.
          *
          * And a few paragraphs later:
          *
          *     Geometry shader input blocks must be declared as arrays and
          *     follow the array declaration and linking rules for all
          *     geometry shader inputs. All other input and output block
          *     arrays must specify an array size.
          *
          * The upshot of this is that the only circumstance where an
          * interface array size *doesn't* need to be specified is on a
          * geometry shader input.
          */
         if (this->array_size == NULL &&
             (state->target != geometry_shader || !this->layout.flags.q.in)) {
            _mesa_glsl_error(&loc, state,
                             "only geometry shader inputs may be unsized "
                             "instance block arrays");

         }

         const glsl_type *block_array_type =
            process_array_type(&loc, block_type, this->array_size, state);

         var = new(state) ir_variable(block_array_type,
                                      this->instance_name,
                                      var_mode);
      } else {
         var = new(state) ir_variable(block_type,
                                      this->instance_name,
                                      var_mode);
      }

      if (state->target == geometry_shader && var_mode == ir_var_shader_in)
         handle_geometry_shader_input_decl(state, loc, var);

      if (ir_variable *earlier =
          state->symbols->get_variable(this->instance_name)) {
         if (!redeclaring_per_vertex) {
            _mesa_glsl_error(&loc, state, "`%s' redeclared",
                             this->instance_name);
         }
         earlier->how_declared = ir_var_declared_normally;
         earlier->type = var->type;
         earlier->reinit_interface_type(block_type);
         delete var;
      } else {
         state->symbols->add_variable(var);
         instructions->push_tail(var);
      }
   } else {
      /* In order to have an array size, the block must also be declared with
       * an instane name.
       */
      assert(!this->is_array);

      for (unsigned i = 0; i < num_variables; i++) {
         ir_variable *var =
            new(state) ir_variable(fields[i].type,
                                   ralloc_strdup(state, fields[i].name),
                                   var_mode);
         var->interpolation = fields[i].interpolation;
         var->centroid = fields[i].centroid;
         var->init_interface_type(block_type);

         if (redeclaring_per_vertex) {
            ir_variable *earlier =
               get_variable_being_redeclared(var, loc, state,
                                             true /* allow_all_redeclarations */);
            if (strncmp(var->name, "gl_", 3) != 0 || earlier == NULL) {
               _mesa_glsl_error(&loc, state,
                                "redeclaration of gl_PerVertex can only "
                                "include built-in variables");
            } else if (earlier->how_declared == ir_var_declared_normally) {
               _mesa_glsl_error(&loc, state,
                                "`%s' has already been redeclared", var->name);
            } else {
               earlier->how_declared = ir_var_declared_in_block;
               earlier->reinit_interface_type(block_type);
            }
            continue;
         }

         if (state->symbols->get_variable(var->name) != NULL)
            _mesa_glsl_error(&loc, state, "`%s' redeclared", var->name);

         /* Propagate the "binding" keyword into this UBO's fields;
          * the UBO declaration itself doesn't get an ir_variable unless it
          * has an instance name.  This is ugly.
          */
         var->explicit_binding = this->layout.flags.q.explicit_binding;
         var->binding = this->layout.binding;

         state->symbols->add_variable(var);
         instructions->push_tail(var);
      }

      if (redeclaring_per_vertex && block_type != earlier_per_vertex) {
         /* From section 7.1 ("Built-in Language Variables") of the GLSL 4.10 spec:
          *
          *     It is also a compilation error ... to redeclare a built-in
          *     block and then use a member from that built-in block that was
          *     not included in the redeclaration.
          *
          * This appears to be a clarification to the behaviour established
          * for gl_PerVertex by GLSL 1.50, therefore we implement this
          * behaviour regardless of GLSL version.
          *
          * To prevent the shader from using a member that was not included in
          * the redeclaration, we disable any ir_variables that are still
          * associated with the old declaration of gl_PerVertex (since we've
          * already updated all of the variables contained in the new
          * gl_PerVertex to point to it).
          *
          * As a side effect this will prevent
          * validate_intrastage_interface_blocks() from getting confused and
          * thinking there are conflicting definitions of gl_PerVertex in the
          * shader.
          */
         foreach_list_safe(node, instructions) {
            ir_variable *const var = ((ir_instruction *) node)->as_variable();
            if (var != NULL &&
                var->get_interface_type() == earlier_per_vertex &&
                var->mode == var_mode) {
               if (var->how_declared == ir_var_declared_normally) {
                  _mesa_glsl_error(&loc, state,
                                   "redeclaration of gl_PerVertex cannot "
                                   "follow a redeclaration of `%s'",
                                   var->name);
               }
               state->symbols->disable_variable(var->name);
               var->remove();
            }
         }
      }
   }

   return NULL;
}


ir_rvalue *
ast_gs_input_layout::hir(exec_list *instructions,
                         struct _mesa_glsl_parse_state *state)
{
   YYLTYPE loc = this->get_location();

   /* If any geometry input layout declaration preceded this one, make sure it
    * was consistent with this one.
    */
   if (state->gs_input_prim_type_specified &&
       state->gs_input_prim_type != this->prim_type) {
      _mesa_glsl_error(&loc, state,
                       "geometry shader input layout does not match"
                       " previous declaration");
      return NULL;
   }

   /* If any shader inputs occurred before this declaration and specified an
    * array size, make sure the size they specified is consistent with the
    * primitive type.
    */
   unsigned num_vertices = vertices_per_prim(this->prim_type);
   if (state->gs_input_size != 0 && state->gs_input_size != num_vertices) {
      _mesa_glsl_error(&loc, state,
                       "this geometry shader input layout implies %u vertices"
                       " per primitive, but a previous input is declared"
                       " with size %u", num_vertices, state->gs_input_size);
      return NULL;
   }

   state->gs_input_prim_type_specified = true;
   state->gs_input_prim_type = this->prim_type;

   /* If any shader inputs occurred before this declaration and did not
    * specify an array size, their size is determined now.
    */
   foreach_list (node, instructions) {
      ir_variable *var = ((ir_instruction *) node)->as_variable();
      if (var == NULL || var->mode != ir_var_shader_in)
         continue;

      /* Note: gl_PrimitiveIDIn has mode ir_var_shader_in, but it's not an
       * array; skip it.
       */

      if (var->type->is_unsized_array()) {
         if (var->max_array_access >= num_vertices) {
            _mesa_glsl_error(&loc, state,
                             "this geometry shader input layout implies %u"
                             " vertices, but an access to element %u of input"
                             " `%s' already exists", num_vertices,
                             var->max_array_access, var->name);
         } else {
            var->type = glsl_type::get_array_instance(var->type->fields.array,
                                                      num_vertices);
         }
      }
   }

   return NULL;
}


static void
detect_conflicting_assignments(struct _mesa_glsl_parse_state *state,
			       exec_list *instructions)
{
   bool gl_FragColor_assigned = false;
   bool gl_FragData_assigned = false;
   bool user_defined_fs_output_assigned = false;
   ir_variable *user_defined_fs_output = NULL;

   /* It would be nice to have proper location information. */
   YYLTYPE loc;
   memset(&loc, 0, sizeof(loc));

   foreach_list(node, instructions) {
      ir_variable *var = ((ir_instruction *)node)->as_variable();

      if (!var || !var->assigned)
	 continue;

      if (strcmp(var->name, "gl_FragColor") == 0)
	 gl_FragColor_assigned = true;
      else if (strcmp(var->name, "gl_FragData") == 0)
	 gl_FragData_assigned = true;
      else if (strncmp(var->name, "gl_", 3) != 0) {
	 if (state->target == fragment_shader &&
	     var->mode == ir_var_shader_out) {
	    user_defined_fs_output_assigned = true;
	    user_defined_fs_output = var;
	 }
      }
   }

   /* From the GLSL 1.30 spec:
    *
    *     "If a shader statically assigns a value to gl_FragColor, it
    *      may not assign a value to any element of gl_FragData. If a
    *      shader statically writes a value to any element of
    *      gl_FragData, it may not assign a value to
    *      gl_FragColor. That is, a shader may assign values to either
    *      gl_FragColor or gl_FragData, but not both. Multiple shaders
    *      linked together must also consistently write just one of
    *      these variables.  Similarly, if user declared output
    *      variables are in use (statically assigned to), then the
    *      built-in variables gl_FragColor and gl_FragData may not be
    *      assigned to. These incorrect usages all generate compile
    *      time errors."
    */
   if (gl_FragColor_assigned && gl_FragData_assigned) {
      _mesa_glsl_error(&loc, state, "fragment shader writes to both "
		       "`gl_FragColor' and `gl_FragData'");
   } else if (gl_FragColor_assigned && user_defined_fs_output_assigned) {
      _mesa_glsl_error(&loc, state, "fragment shader writes to both "
		       "`gl_FragColor' and `%s'",
		       user_defined_fs_output->name);
   } else if (gl_FragData_assigned && user_defined_fs_output_assigned) {
      _mesa_glsl_error(&loc, state, "fragment shader writes to both "
		       "`gl_FragData' and `%s'",
		       user_defined_fs_output->name);
   }
}


static void
remove_per_vertex_blocks(exec_list *instructions,
                         _mesa_glsl_parse_state *state, ir_variable_mode mode)
{
   /* Find the gl_PerVertex interface block of the appropriate (in/out) mode,
    * if it exists in this shader type.
    */
   const glsl_type *per_vertex = NULL;
   switch (mode) {
   case ir_var_shader_in:
      if (ir_variable *gl_in = state->symbols->get_variable("gl_in"))
         per_vertex = gl_in->get_interface_type();
      break;
   case ir_var_shader_out:
      if (ir_variable *gl_Position =
          state->symbols->get_variable("gl_Position")) {
         per_vertex = gl_Position->get_interface_type();
      }
      break;
   default:
      assert(!"Unexpected mode");
      break;
   }

   /* If we didn't find a built-in gl_PerVertex interface block, then we don't
    * need to do anything.
    */
   if (per_vertex == NULL)
      return;

   /* If the interface block is used by the shader, then we don't need to do
    * anything.
    */
   interface_block_usage_visitor v(mode, per_vertex);
   v.run(instructions);
   if (v.usage_found())
      return;

   /* Remove any ir_variable declarations that refer to the interface block
    * we're removing.
    */
   foreach_list_safe(node, instructions) {
      ir_variable *const var = ((ir_instruction *) node)->as_variable();
      if (var != NULL && var->get_interface_type() == per_vertex &&
          var->mode == mode) {
         state->symbols->disable_variable(var->name);
         var->remove();
      }
   }
}