aboutsummaryrefslogtreecommitdiff
path: root/mesalib/src/glsl/link_uniforms.cpp
blob: 400e13479330195eec954e85e63834039196cba4 (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
/*
 * Copyright © 2011 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.
 */

#include "main/core.h"
#include "ir.h"
#include "linker.h"
#include "ir_uniform.h"
#include "glsl_symbol_table.h"
#include "program/hash_table.h"
#include "program.h"

/**
 * \file link_uniforms.cpp
 * Assign locations for GLSL uniforms.
 *
 * \author Ian Romanick <ian.d.romanick@intel.com>
 */

/**
 * Used by linker to indicate uniforms that have no location set.
 */
#define UNMAPPED_UNIFORM_LOC ~0u

/**
 * Count the backing storage requirements for a type
 */
static unsigned
values_for_type(const glsl_type *type)
{
   if (type->is_sampler()) {
      return 1;
   } else if (type->is_array() && type->fields.array->is_sampler()) {
      return type->array_size();
   } else {
      return type->component_slots();
   }
}

void
program_resource_visitor::process(const glsl_type *type, const char *name)
{
   assert(type->without_array()->is_record()
          || type->without_array()->is_interface());

   char *name_copy = ralloc_strdup(NULL, name);
   recursion(type, &name_copy, strlen(name), false, NULL, false);
   ralloc_free(name_copy);
}

void
program_resource_visitor::process(ir_variable *var)
{
   const glsl_type *t = var->type;
   const bool row_major =
      var->data.matrix_layout == GLSL_MATRIX_LAYOUT_ROW_MAJOR;

   /* false is always passed for the row_major parameter to the other
    * processing functions because no information is available to do
    * otherwise.  See the warning in linker.h.
    */

   /* Only strdup the name if we actually will need to modify it. */
   if (var->data.from_named_ifc_block_array) {
      /* lower_named_interface_blocks created this variable by lowering an
       * interface block array to an array variable.  For example if the
       * original source code was:
       *
       *     out Blk { vec4 bar } foo[3];
       *
       * Then the variable is now:
       *
       *     out vec4 bar[3];
       *
       * We need to visit each array element using the names constructed like
       * so:
       *
       *     Blk[0].bar
       *     Blk[1].bar
       *     Blk[2].bar
       */
      assert(t->is_array());
      const glsl_type *ifc_type = var->get_interface_type();
      char *name = ralloc_strdup(NULL, ifc_type->name);
      size_t name_length = strlen(name);
      for (unsigned i = 0; i < t->length; i++) {
         size_t new_length = name_length;
         ralloc_asprintf_rewrite_tail(&name, &new_length, "[%u].%s", i,
                                      var->name);
         /* Note: row_major is only meaningful for uniform blocks, and
          * lowering is only applied to non-uniform interface blocks, so we
          * can safely pass false for row_major.
          */
         recursion(var->type, &name, new_length, row_major, NULL, false);
      }
      ralloc_free(name);
   } else if (var->data.from_named_ifc_block_nonarray) {
      /* lower_named_interface_blocks created this variable by lowering a
       * named interface block (non-array) to an ordinary variable.  For
       * example if the original source code was:
       *
       *     out Blk { vec4 bar } foo;
       *
       * Then the variable is now:
       *
       *     out vec4 bar;
       *
       * We need to visit this variable using the name:
       *
       *     Blk.bar
       */
      const glsl_type *ifc_type = var->get_interface_type();
      char *name = ralloc_asprintf(NULL, "%s.%s", ifc_type->name, var->name);
      /* Note: row_major is only meaningful for uniform blocks, and lowering
       * is only applied to non-uniform interface blocks, so we can safely
       * pass false for row_major.
       */
      recursion(var->type, &name, strlen(name), row_major, NULL, false);
      ralloc_free(name);
   } else if (t->without_array()->is_record()) {
      char *name = ralloc_strdup(NULL, var->name);
      recursion(var->type, &name, strlen(name), row_major, NULL, false);
      ralloc_free(name);
   } else if (t->is_interface()) {
      char *name = ralloc_strdup(NULL, var->type->name);
      recursion(var->type, &name, strlen(name), row_major, NULL, false);
      ralloc_free(name);
   } else if (t->is_array() && t->fields.array->is_interface()) {
      char *name = ralloc_strdup(NULL, var->type->fields.array->name);
      recursion(var->type, &name, strlen(name), row_major, NULL, false);
      ralloc_free(name);
   } else {
      this->visit_field(t, var->name, row_major, NULL, false);
   }
}

void
program_resource_visitor::recursion(const glsl_type *t, char **name,
                                    size_t name_length, bool row_major,
                                    const glsl_type *record_type,
                                    bool last_field)
{
   /* Records need to have each field processed individually.
    *
    * Arrays of records need to have each array element processed
    * individually, then each field of the resulting array elements processed
    * individually.
    */
   if (t->is_record() || t->is_interface()) {
      if (record_type == NULL && t->is_record())
         record_type = t;

      for (unsigned i = 0; i < t->length; i++) {
	 const char *field = t->fields.structure[i].name;
	 size_t new_length = name_length;

         if (t->fields.structure[i].type->is_record())
            this->visit_field(&t->fields.structure[i]);

         /* Append '.field' to the current variable name. */
         if (name_length == 0) {
            ralloc_asprintf_rewrite_tail(name, &new_length, "%s", field);
         } else {
            ralloc_asprintf_rewrite_tail(name, &new_length, ".%s", field);
         }

         /* The layout of structures at the top level of the block is set
          * during parsing.  For matrices contained in multiple levels of
          * structures in the block, the inner structures have no layout.
          * These cases must potentially inherit the layout from the outer
          * levels.
          */
         bool field_row_major = row_major;
         const enum glsl_matrix_layout matrix_layout =
            glsl_matrix_layout(t->fields.structure[i].matrix_layout);
         if (matrix_layout == GLSL_MATRIX_LAYOUT_ROW_MAJOR) {
            field_row_major = true;
         } else if (matrix_layout == GLSL_MATRIX_LAYOUT_COLUMN_MAJOR) {
            field_row_major = false;
         }

         recursion(t->fields.structure[i].type, name, new_length,
                   field_row_major,
                   record_type,
                   (i + 1) == t->length);

         /* Only the first leaf-field of the record gets called with the
          * record type pointer.
          */
         record_type = NULL;
      }
   } else if (t->is_array() && (t->fields.array->is_record()
                                || t->fields.array->is_interface())) {
      if (record_type == NULL && t->fields.array->is_record())
         record_type = t->fields.array;

      for (unsigned i = 0; i < t->length; i++) {
	 size_t new_length = name_length;

	 /* Append the subscript to the current variable name */
	 ralloc_asprintf_rewrite_tail(name, &new_length, "[%u]", i);

         recursion(t->fields.array, name, new_length, row_major,
                   record_type,
                   (i + 1) == t->length);

         /* Only the first leaf-field of the record gets called with the
          * record type pointer.
          */
         record_type = NULL;
      }
   } else {
      this->visit_field(t, *name, row_major, record_type, last_field);
   }
}

void
program_resource_visitor::visit_field(const glsl_type *type, const char *name,
                                      bool row_major,
                                      const glsl_type *,
                                      bool /* last_field */)
{
   visit_field(type, name, row_major);
}

void
program_resource_visitor::visit_field(const glsl_struct_field *field)
{
   (void) field;
   /* empty */
}

namespace {

/**
 * Class to help calculate the storage requirements for a set of uniforms
 *
 * As uniforms are added to the active set the number of active uniforms and
 * the storage requirements for those uniforms are accumulated.  The active
 * uniforms are added the the hash table supplied to the constructor.
 *
 * If the same uniform is added multiple times (i.e., once for each shader
 * target), it will only be accounted once.
 */
class count_uniform_size : public program_resource_visitor {
public:
   count_uniform_size(struct string_to_uint_map *map)
      : num_active_uniforms(0), num_values(0), num_shader_samplers(0),
        num_shader_images(0), num_shader_uniform_components(0),
        is_ubo_var(false), map(map)
   {
      /* empty */
   }

   void start_shader()
   {
      this->num_shader_samplers = 0;
      this->num_shader_images = 0;
      this->num_shader_uniform_components = 0;
   }

   void process(ir_variable *var)
   {
      this->is_ubo_var = var->is_in_uniform_block();
      if (var->is_interface_instance())
         program_resource_visitor::process(var->get_interface_type(),
                                           var->get_interface_type()->name);
      else
         program_resource_visitor::process(var);
   }

   /**
    * Total number of active uniforms counted
    */
   unsigned num_active_uniforms;

   /**
    * Number of data values required to back the storage for the active uniforms
    */
   unsigned num_values;

   /**
    * Number of samplers used
    */
   unsigned num_shader_samplers;

   /**
    * Number of images used
    */
   unsigned num_shader_images;

   /**
    * Number of uniforms used in the current shader
    */
   unsigned num_shader_uniform_components;

   bool is_ubo_var;

private:
   virtual void visit_field(const glsl_type *type, const char *name,
                            bool row_major)
   {
      assert(!type->without_array()->is_record());
      assert(!type->without_array()->is_interface());

      (void) row_major;

      /* Count the number of samplers regardless of whether the uniform is
       * already in the hash table.  The hash table prevents adding the same
       * uniform for multiple shader targets, but in this case we want to
       * count it for each shader target.
       */
      const unsigned values = values_for_type(type);
      if (type->contains_sampler()) {
         this->num_shader_samplers += values;
      } else if (type->contains_image()) {
         this->num_shader_images += values;

         /* As drivers are likely to represent image uniforms as
          * scalar indices, count them against the limit of uniform
          * components in the default block.  The spec allows image
          * uniforms to use up no more than one scalar slot.
          */
         this->num_shader_uniform_components += values;
      } else {
	 /* Accumulate the total number of uniform slots used by this shader.
	  * Note that samplers do not count against this limit because they
	  * don't use any storage on current hardware.
	  */
	 if (!is_ubo_var)
	    this->num_shader_uniform_components += values;
      }

      /* If the uniform is already in the map, there's nothing more to do.
       */
      unsigned id;
      if (this->map->get(id, name))
	 return;

      this->map->put(this->num_active_uniforms, name);

      /* Each leaf uniform occupies one entry in the list of active
       * uniforms.
       */
      this->num_active_uniforms++;
      this->num_values += values;
   }

   struct string_to_uint_map *map;
};

} /* anonymous namespace */

/**
 * Class to help parcel out pieces of backing storage to uniforms
 *
 * Each uniform processed has some range of the \c gl_constant_value
 * structures associated with it.  The association is done by finding
 * the uniform in the \c string_to_uint_map and using the value from
 * the map to connect that slot in the \c gl_uniform_storage table
 * with the next available slot in the \c gl_constant_value array.
 *
 * \warning
 * This class assumes that every uniform that will be processed is
 * already in the \c string_to_uint_map.  In addition, it assumes that
 * the \c gl_uniform_storage and \c gl_constant_value arrays are "big
 * enough."
 */
class parcel_out_uniform_storage : public program_resource_visitor {
public:
   parcel_out_uniform_storage(struct string_to_uint_map *map,
			      struct gl_uniform_storage *uniforms,
			      union gl_constant_value *values)
      : map(map), uniforms(uniforms), values(values)
   {
   }

   void start_shader(gl_shader_stage shader_type)
   {
      assert(shader_type < MESA_SHADER_STAGES);
      this->shader_type = shader_type;

      this->shader_samplers_used = 0;
      this->shader_shadow_samplers = 0;
      this->next_sampler = 0;
      this->next_image = 0;
      memset(this->targets, 0, sizeof(this->targets));
   }

   void set_and_process(struct gl_shader_program *prog,
			ir_variable *var)
   {
      current_var = var;
      field_counter = 0;

      ubo_block_index = -1;
      if (var->is_in_uniform_block()) {
         if (var->is_interface_instance() && var->type->is_array()) {
            unsigned l = strlen(var->get_interface_type()->name);

            for (unsigned i = 0; i < prog->NumUniformBlocks; i++) {
               if (strncmp(var->get_interface_type()->name,
                           prog->UniformBlocks[i].Name,
                           l) == 0
                   && prog->UniformBlocks[i].Name[l] == '[') {
                  ubo_block_index = i;
                  break;
               }
            }
         } else {
            for (unsigned i = 0; i < prog->NumUniformBlocks; i++) {
               if (strcmp(var->get_interface_type()->name,
                          prog->UniformBlocks[i].Name) == 0) {
                  ubo_block_index = i;
                  break;
               }
	    }
	 }
	 assert(ubo_block_index != -1);

         /* Uniform blocks that were specified with an instance name must be
          * handled a little bit differently.  The name of the variable is the
          * name used to reference the uniform block instead of being the name
          * of a variable within the block.  Therefore, searching for the name
          * within the block will fail.
          */
         if (var->is_interface_instance()) {
            ubo_byte_offset = 0;
         } else {
            const struct gl_uniform_block *const block =
               &prog->UniformBlocks[ubo_block_index];

            assert(var->data.location != -1);

            const struct gl_uniform_buffer_variable *const ubo_var =
               &block->Uniforms[var->data.location];

            ubo_byte_offset = ubo_var->Offset;
         }

         if (var->is_interface_instance())
            process(var->get_interface_type(),
                    var->get_interface_type()->name);
         else
            process(var);
      } else
         process(var);
   }

   int ubo_block_index;
   int ubo_byte_offset;
   gl_shader_stage shader_type;

private:
   void handle_samplers(const glsl_type *base_type,
                        struct gl_uniform_storage *uniform)
   {
      if (base_type->is_sampler()) {
         uniform->sampler[shader_type].index = this->next_sampler;
         uniform->sampler[shader_type].active = true;

         /* Increment the sampler by 1 for non-arrays and by the number of
          * array elements for arrays.
          */
         this->next_sampler +=
               MAX2(1, uniform->array_elements);

         const gl_texture_index target = base_type->sampler_index();
         const unsigned shadow = base_type->sampler_shadow;
         for (unsigned i = uniform->sampler[shader_type].index;
              i < MIN2(this->next_sampler, MAX_SAMPLERS);
              i++) {
            this->targets[i] = target;
            this->shader_samplers_used |= 1U << i;
            this->shader_shadow_samplers |= shadow << i;
         }
      } else {
         uniform->sampler[shader_type].index = ~0;
         uniform->sampler[shader_type].active = false;
      }
   }

   void handle_images(const glsl_type *base_type,
                      struct gl_uniform_storage *uniform)
   {
      if (base_type->is_image()) {
         uniform->image[shader_type].index = this->next_image;
         uniform->image[shader_type].active = true;

         /* Increment the image index by 1 for non-arrays and by the
          * number of array elements for arrays.
          */
         this->next_image += MAX2(1, uniform->array_elements);

      } else {
         uniform->image[shader_type].index = ~0;
         uniform->image[shader_type].active = false;
      }
   }

   virtual void visit_field(const glsl_type *type, const char *name,
                            bool row_major)
   {
      (void) type;
      (void) name;
      (void) row_major;
      assert(!"Should not get here.");
   }

   virtual void visit_field(const glsl_type *type, const char *name,
                            bool row_major, const glsl_type *record_type,
                            bool last_field)
   {
      assert(!type->without_array()->is_record());
      assert(!type->without_array()->is_interface());

      unsigned id;
      bool found = this->map->get(id, name);
      assert(found);

      if (!found)
	 return;

      const glsl_type *base_type;
      if (type->is_array()) {
	 this->uniforms[id].array_elements = type->length;
	 base_type = type->fields.array;
      } else {
	 this->uniforms[id].array_elements = 0;
	 base_type = type;
      }

      /* This assigns uniform indices to sampler and image uniforms. */
      handle_samplers(base_type, &this->uniforms[id]);
      handle_images(base_type, &this->uniforms[id]);

      /* If there is already storage associated with this uniform, it means
       * that it was set while processing an earlier shader stage.  For
       * example, we may be processing the uniform in the fragment shader, but
       * the uniform was already processed in the vertex shader.
       */
      if (this->uniforms[id].storage != NULL) {
         return;
      }

      /* Assign explicit locations. */
      if (current_var->data.explicit_location) {
         /* Set sequential locations for struct fields. */
         if (record_type != NULL) {
            const unsigned entries = MAX2(1, this->uniforms[id].array_elements);
            this->uniforms[id].remap_location =
               current_var->data.location + field_counter;
            field_counter += entries;
         } else {
            this->uniforms[id].remap_location = current_var->data.location;
         }
      } else {
         /* Initialize to to indicate that no location is set */
         this->uniforms[id].remap_location = UNMAPPED_UNIFORM_LOC;
      }

      this->uniforms[id].name = ralloc_strdup(this->uniforms, name);
      this->uniforms[id].type = base_type;
      this->uniforms[id].initialized = 0;
      this->uniforms[id].num_driver_storage = 0;
      this->uniforms[id].driver_storage = NULL;
      this->uniforms[id].storage = this->values;
      this->uniforms[id].atomic_buffer_index = -1;
      if (this->ubo_block_index != -1) {
	 this->uniforms[id].block_index = this->ubo_block_index;

	 const unsigned alignment = record_type
	    ? record_type->std140_base_alignment(row_major)
	    : type->std140_base_alignment(row_major);
	 this->ubo_byte_offset = glsl_align(this->ubo_byte_offset, alignment);
	 this->uniforms[id].offset = this->ubo_byte_offset;
	 this->ubo_byte_offset += type->std140_size(row_major);

         if (last_field)
            this->ubo_byte_offset = glsl_align(this->ubo_byte_offset, 16);

	 if (type->is_array()) {
	    this->uniforms[id].array_stride =
	       glsl_align(type->fields.array->std140_size(row_major), 16);
	 } else {
	    this->uniforms[id].array_stride = 0;
	 }

	 if (type->without_array()->is_matrix()) {
	    this->uniforms[id].matrix_stride = 16;
	    this->uniforms[id].row_major = row_major;
	 } else {
	    this->uniforms[id].matrix_stride = 0;
	    this->uniforms[id].row_major = false;
	 }
      } else {
	 this->uniforms[id].block_index = -1;
	 this->uniforms[id].offset = -1;
	 this->uniforms[id].array_stride = -1;
	 this->uniforms[id].matrix_stride = -1;
	 this->uniforms[id].row_major = false;
      }

      this->values += values_for_type(type);
   }

   struct string_to_uint_map *map;

   struct gl_uniform_storage *uniforms;
   unsigned next_sampler;
   unsigned next_image;

public:
   union gl_constant_value *values;

   gl_texture_index targets[MAX_SAMPLERS];

   /**
    * Current variable being processed.
    */
   ir_variable *current_var;

   /**
    * Field counter is used to take care that uniform structures
    * with explicit locations get sequential locations.
    */
   unsigned field_counter;

   /**
    * Mask of samplers used by the current shader stage.
    */
   unsigned shader_samplers_used;

   /**
    * Mask of samplers used by the current shader stage for shadows.
    */
   unsigned shader_shadow_samplers;
};

/**
 * Merges a uniform block into an array of uniform blocks that may or
 * may not already contain a copy of it.
 *
 * Returns the index of the new block in the array.
 */
int
link_cross_validate_uniform_block(void *mem_ctx,
				  struct gl_uniform_block **linked_blocks,
				  unsigned int *num_linked_blocks,
				  struct gl_uniform_block *new_block)
{
   for (unsigned int i = 0; i < *num_linked_blocks; i++) {
      struct gl_uniform_block *old_block = &(*linked_blocks)[i];

      if (strcmp(old_block->Name, new_block->Name) == 0)
	 return link_uniform_blocks_are_compatible(old_block, new_block)
	    ? i : -1;
   }

   *linked_blocks = reralloc(mem_ctx, *linked_blocks,
			     struct gl_uniform_block,
			     *num_linked_blocks + 1);
   int linked_block_index = (*num_linked_blocks)++;
   struct gl_uniform_block *linked_block = &(*linked_blocks)[linked_block_index];

   memcpy(linked_block, new_block, sizeof(*new_block));
   linked_block->Uniforms = ralloc_array(*linked_blocks,
					 struct gl_uniform_buffer_variable,
					 linked_block->NumUniforms);

   memcpy(linked_block->Uniforms,
	  new_block->Uniforms,
	  sizeof(*linked_block->Uniforms) * linked_block->NumUniforms);

   for (unsigned int i = 0; i < linked_block->NumUniforms; i++) {
      struct gl_uniform_buffer_variable *ubo_var =
	 &linked_block->Uniforms[i];

      if (ubo_var->Name == ubo_var->IndexName) {
         ubo_var->Name = ralloc_strdup(*linked_blocks, ubo_var->Name);
         ubo_var->IndexName = ubo_var->Name;
      } else {
         ubo_var->Name = ralloc_strdup(*linked_blocks, ubo_var->Name);
         ubo_var->IndexName = ralloc_strdup(*linked_blocks, ubo_var->IndexName);
      }
   }

   return linked_block_index;
}

/**
 * Walks the IR and update the references to uniform blocks in the
 * ir_variables to point at linked shader's list (previously, they
 * would point at the uniform block list in one of the pre-linked
 * shaders).
 */
static void
link_update_uniform_buffer_variables(struct gl_shader *shader)
{
   foreach_in_list(ir_instruction, node, shader->ir) {
      ir_variable *const var = node->as_variable();

      if ((var == NULL) || !var->is_in_uniform_block())
	 continue;

      assert(var->data.mode == ir_var_uniform);

      if (var->is_interface_instance()) {
         var->data.location = 0;
         continue;
      }

      bool found = false;
      char sentinel = '\0';

      if (var->type->is_record()) {
         sentinel = '.';
      } else if (var->type->is_array()
                 && var->type->fields.array->is_record()) {
         sentinel = '[';
      }

      const unsigned l = strlen(var->name);
      for (unsigned i = 0; i < shader->NumUniformBlocks; i++) {
	 for (unsigned j = 0; j < shader->UniformBlocks[i].NumUniforms; j++) {
            if (sentinel) {
               const char *begin = shader->UniformBlocks[i].Uniforms[j].Name;
               const char *end = strchr(begin, sentinel);

               if (end == NULL)
                  continue;

               if ((ptrdiff_t) l != (end - begin))
                  continue;

               if (strncmp(var->name, begin, l) == 0) {
                  found = true;
                  var->data.location = j;
                  break;
               }
            } else if (!strcmp(var->name,
                               shader->UniformBlocks[i].Uniforms[j].Name)) {
	       found = true;
	       var->data.location = j;
	       break;
	    }
	 }
	 if (found)
	    break;
      }
      assert(found);
   }
}

/**
 * Scan the program for image uniforms and store image unit access
 * information into the gl_shader data structure.
 */
static void
link_set_image_access_qualifiers(struct gl_shader_program *prog)
{
   for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
      gl_shader *sh = prog->_LinkedShaders[i];

      if (sh == NULL)
	 continue;

      foreach_in_list(ir_instruction, node, sh->ir) {
	 ir_variable *var = node->as_variable();

         if (var && var->data.mode == ir_var_uniform &&
             var->type->contains_image()) {
            unsigned id = 0;
            bool found = prog->UniformHash->get(id, var->name);
            assert(found);
            (void) found;
            const gl_uniform_storage *storage = &prog->UniformStorage[id];
            const unsigned index = storage->image[i].index;
            const GLenum access = (var->data.image_read_only ? GL_READ_ONLY :
                                   var->data.image_write_only ? GL_WRITE_ONLY :
                                   GL_READ_WRITE);

            for (unsigned j = 0; j < MAX2(1, storage->array_elements); ++j)
               sh->ImageAccess[index + j] = access;
         }
      }
   }
}

void
link_assign_uniform_locations(struct gl_shader_program *prog,
                              unsigned int boolean_true)
{
   ralloc_free(prog->UniformStorage);
   prog->UniformStorage = NULL;
   prog->NumUserUniformStorage = 0;

   if (prog->UniformHash != NULL) {
      prog->UniformHash->clear();
   } else {
      prog->UniformHash = new string_to_uint_map;
   }

   /* First pass: Count the uniform resources used by the user-defined
    * uniforms.  While this happens, each active uniform will have an index
    * assigned to it.
    *
    * Note: this is *NOT* the index that is returned to the application by
    * glGetUniformLocation.
    */
   count_uniform_size uniform_size(prog->UniformHash);
   for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
      struct gl_shader *sh = prog->_LinkedShaders[i];

      if (sh == NULL)
	 continue;

      /* Uniforms that lack an initializer in the shader code have an initial
       * value of zero.  This includes sampler uniforms.
       *
       * Page 24 (page 30 of the PDF) of the GLSL 1.20 spec says:
       *
       *     "The link time initial value is either the value of the variable's
       *     initializer, if present, or 0 if no initializer is present. Sampler
       *     types cannot have initializers."
       */
      memset(sh->SamplerUnits, 0, sizeof(sh->SamplerUnits));
      memset(sh->ImageUnits, 0, sizeof(sh->ImageUnits));

      link_update_uniform_buffer_variables(sh);

      /* Reset various per-shader target counts.
       */
      uniform_size.start_shader();

      foreach_in_list(ir_instruction, node, sh->ir) {
	 ir_variable *const var = node->as_variable();

	 if ((var == NULL) || (var->data.mode != ir_var_uniform))
	    continue;

	 /* FINISHME: Update code to process built-in uniforms!
	  */
	 if (is_gl_identifier(var->name)) {
	    uniform_size.num_shader_uniform_components +=
	       var->type->component_slots();
	    continue;
	 }

	 uniform_size.process(var);
      }

      sh->num_samplers = uniform_size.num_shader_samplers;
      sh->NumImages = uniform_size.num_shader_images;
      sh->num_uniform_components = uniform_size.num_shader_uniform_components;

      sh->num_combined_uniform_components = sh->num_uniform_components;
      for (unsigned i = 0; i < sh->NumUniformBlocks; i++) {
	 sh->num_combined_uniform_components +=
	    sh->UniformBlocks[i].UniformBufferSize / 4;
      }
   }

   const unsigned num_user_uniforms = uniform_size.num_active_uniforms;
   const unsigned num_data_slots = uniform_size.num_values;

   /* On the outside chance that there were no uniforms, bail out.
    */
   if (num_user_uniforms == 0)
      return;

   struct gl_uniform_storage *uniforms =
      rzalloc_array(prog, struct gl_uniform_storage, num_user_uniforms);
   union gl_constant_value *data =
      rzalloc_array(uniforms, union gl_constant_value, num_data_slots);
#ifndef NDEBUG
   union gl_constant_value *data_end = &data[num_data_slots];
#endif

   parcel_out_uniform_storage parcel(prog->UniformHash, uniforms, data);

   for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
      if (prog->_LinkedShaders[i] == NULL)
	 continue;

      parcel.start_shader((gl_shader_stage)i);

      foreach_in_list(ir_instruction, node, prog->_LinkedShaders[i]->ir) {
	 ir_variable *const var = node->as_variable();

	 if ((var == NULL) || (var->data.mode != ir_var_uniform))
	    continue;

	 /* FINISHME: Update code to process built-in uniforms!
	  */
	 if (is_gl_identifier(var->name))
	    continue;

	 parcel.set_and_process(prog, var);
      }

      prog->_LinkedShaders[i]->active_samplers = parcel.shader_samplers_used;
      prog->_LinkedShaders[i]->shadow_samplers = parcel.shader_shadow_samplers;

      STATIC_ASSERT(sizeof(prog->_LinkedShaders[i]->SamplerTargets) == sizeof(parcel.targets));
      memcpy(prog->_LinkedShaders[i]->SamplerTargets, parcel.targets,
             sizeof(prog->_LinkedShaders[i]->SamplerTargets));
   }

   /* Reserve all the explicit locations of the active uniforms. */
   for (unsigned i = 0; i < num_user_uniforms; i++) {
      if (uniforms[i].remap_location != UNMAPPED_UNIFORM_LOC) {
         /* How many new entries for this uniform? */
         const unsigned entries = MAX2(1, uniforms[i].array_elements);

         /* Set remap table entries point to correct gl_uniform_storage. */
         for (unsigned j = 0; j < entries; j++) {
            unsigned element_loc = uniforms[i].remap_location + j;
            assert(prog->UniformRemapTable[element_loc] ==
                   INACTIVE_UNIFORM_EXPLICIT_LOCATION);
            prog->UniformRemapTable[element_loc] = &uniforms[i];
         }
      }
   }

   /* Reserve locations for rest of the uniforms. */
   for (unsigned i = 0; i < num_user_uniforms; i++) {

      /* Explicit ones have been set already. */
      if (uniforms[i].remap_location != UNMAPPED_UNIFORM_LOC)
         continue;

      /* how many new entries for this uniform? */
      const unsigned entries = MAX2(1, uniforms[i].array_elements);

      /* resize remap table to fit new entries */
      prog->UniformRemapTable =
         reralloc(prog,
                  prog->UniformRemapTable,
                  gl_uniform_storage *,
                  prog->NumUniformRemapTable + entries);

      /* set pointers for this uniform */
      for (unsigned j = 0; j < entries; j++)
         prog->UniformRemapTable[prog->NumUniformRemapTable+j] = &uniforms[i];

      /* set the base location in remap table for the uniform */
      uniforms[i].remap_location = prog->NumUniformRemapTable;

      prog->NumUniformRemapTable += entries;
   }

#ifndef NDEBUG
   for (unsigned i = 0; i < num_user_uniforms; i++) {
      assert(uniforms[i].storage != NULL);
   }

   assert(parcel.values == data_end);
#endif

   prog->NumUserUniformStorage = num_user_uniforms;
   prog->UniformStorage = uniforms;

   link_set_image_access_qualifiers(prog);
   link_set_uniform_initializers(prog, boolean_true);

   return;
}