src/compiler/glsl/link_uniform_block_active_visitor.cpp

   1 /*
   2  * Copyright © 2013 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #include "link_uniform_block_active_visitor.h"
  25 #include "program.h"
  26 #include "linker_util.h"
  27
  28 static link_uniform_block_active *
  29 process_block(void *mem_ctx, struct hash_table *ht, ir_variable *var)
  30 {
  31    const hash_entry *const existing_block =
  32       _mesa_hash_table_search(ht, var->get_interface_type()->name);
  33
  34    const glsl_type *const block_type = var->is_interface_instance()
  35       ? var->type : var->get_interface_type();
  36
  37
  38    /* If a block with this block-name has not previously been seen, add it.
  39     * If a block with this block-name has been seen, it must be identical to
  40     * the block currently being examined.
  41     */
  42    if (existing_block == NULL) {
  43       link_uniform_block_active *const b =
  44          rzalloc(mem_ctx, struct link_uniform_block_active);
  45
  46       b->type = block_type;
  47       b->has_instance_name = var->is_interface_instance();
  48       b->is_shader_storage = var->data.mode == ir_var_shader_storage;
  49
  50       if (var->data.explicit_binding) {
  51          b->has_binding = true;
  52          b->binding = var->data.binding;
  53       } else {
  54          b->has_binding = false;
  55          b->binding = 0;
  56       }
  57
  58       _mesa_hash_table_insert(ht, var->get_interface_type()->name, (void *) b);
  59       return b;
  60    } else {
  61       link_uniform_block_active *const b =
  62          (link_uniform_block_active *) existing_block->data;
  63
  64       if (b->type != block_type
  65           || b->has_instance_name != var->is_interface_instance())
  66          return NULL;
  67       else
  68          return b;
  69    }
  70
  71    assert(!"Should not get here.");
  72    return NULL;
  73 }
  74
  75 /* For arrays of arrays this function will give us a middle ground between
  76  * detecting inactive uniform blocks and structuring them in a way that makes
  77  * it easy to calculate the offset for indirect indexing.
  78  *
  79  * For example given the shader:
  80  *
  81  *   uniform ArraysOfArraysBlock
  82  *   {
  83  *      vec4 a;
  84  *   } i[3][4][5];
  85  *
  86  *   void main()
  87  *   {
  88  *      vec4 b = i[0][1][1].a;
  89  *      gl_Position = i[2][2][3].a + b;
  90  *   }
  91  *
  92  * There are only 2 active blocks above but for the sake of indirect indexing
  93  * and not over complicating the code we will end up with a count of 8.  Here
  94  * each dimension has 2 different indices counted so we end up with 2*2*2
  95  */
  96 static struct uniform_block_array_elements **
  97 process_arrays(void *mem_ctx, ir_dereference_array *ir,
  98                struct link_uniform_block_active *block)
  99 {
 100    if (ir) {
 101       struct uniform_block_array_elements **ub_array_ptr =
 102          process_arrays(mem_ctx, ir->array->as_dereference_array(), block);
 103       if (*ub_array_ptr == NULL) {
 104          *ub_array_ptr = rzalloc(mem_ctx, struct uniform_block_array_elements);
 105          (*ub_array_ptr)->ir = ir;
 106       }
 107
 108       struct uniform_block_array_elements *ub_array = *ub_array_ptr;
 109       ir_constant *c = ir->array_index->as_constant();
 110       if (c) {
 111          /* Index is a constant, so mark just that element used, if not
 112           * already.
 113           */
 114          const unsigned idx = c->get_uint_component(0);
 115
 116          unsigned i;
 117          for (i = 0; i < ub_array->num_array_elements; i++) {
 118             if (ub_array->array_elements[i] == idx)
 119                break;
 120          }
 121
 122          assert(i <= ub_array->num_array_elements);
 123
 124          if (i == ub_array->num_array_elements) {
 125             ub_array->array_elements = reralloc(mem_ctx,
 126                                                 ub_array->array_elements,
 127                                                 unsigned,
 128                                                 ub_array->num_array_elements + 1);
 129
 130             ub_array->array_elements[ub_array->num_array_elements] = idx;
 131
 132             ub_array->num_array_elements++;
 133          }
 134       } else {
 135          /* The array index is not a constant, so mark the entire array used. */
 136          assert(ir->array->type->is_array());
 137          if (ub_array->num_array_elements < ir->array->type->length) {
 138             ub_array->num_array_elements = ir->array->type->length;
 139             ub_array->array_elements = reralloc(mem_ctx,
 140                                                 ub_array->array_elements,
 141                                                 unsigned,
 142                                                 ub_array->num_array_elements);
 143
 144             for (unsigned i = 0; i < ub_array->num_array_elements; i++) {
 145                ub_array->array_elements[i] = i;
 146             }
 147          }
 148       }
 149
 150       return &ub_array->array;
 151    } else {
 152       return &block->array;
 153    }
 154 }
 155
 156 ir_visitor_status
 157 link_uniform_block_active_visitor::visit(ir_variable *var)
 158 {
 159    if (!var->is_in_buffer_block())
 160       return visit_continue;
 161
 162    /* Section 2.11.6 (Uniform Variables) of the OpenGL ES 3.0.3 spec says:
 163     *
 164     *     "All members of a named uniform block declared with a shared or
 165     *     std140 layout qualifier are considered active, even if they are not
 166     *     referenced in any shader in the program. The uniform block itself is
 167     *     also considered active, even if no member of the block is
 168     *     referenced."
 169     */
 170    if (var->get_interface_type_packing() == GLSL_INTERFACE_PACKING_PACKED)
 171       return visit_continue;
 172
 173    /* Process the block.  Bail if there was an error. */
 174    link_uniform_block_active *const b =
 175       process_block(this->mem_ctx, this->ht, var);
 176    if (b == NULL) {
 177       linker_error(this->prog,
 178                    "uniform block `%s' has mismatching definitions",
 179                    var->get_interface_type()->name);
 180       this->success = false;
 181       return visit_stop;
 182    }
 183
 184    assert(b->array == NULL);
 185    assert(b->type != NULL);
 186    assert(!b->type->is_array() || b->has_instance_name);
 187
 188    /* For uniform block arrays declared with a shared or std140 layout
 189     * qualifier, mark all its instances as used.
 190     */
 191    const glsl_type *type = b->type;
 192    struct uniform_block_array_elements **ub_array = &b->array;
 193    while (type->is_array()) {
 194       assert(b->type->length > 0);
 195
 196       *ub_array = rzalloc(this->mem_ctx, struct uniform_block_array_elements);
 197       (*ub_array)->num_array_elements = type->length;
 198       (*ub_array)->array_elements = reralloc(this->mem_ctx,
 199                                              (*ub_array)->array_elements,
 200                                              unsigned,
 201                                              (*ub_array)->num_array_elements);
 202
 203       for (unsigned i = 0; i < (*ub_array)->num_array_elements; i++) {
 204          (*ub_array)->array_elements[i] = i;
 205       }
 206       ub_array = &(*ub_array)->array;
 207       type = type->fields.array;
 208    }
 209
 210    return visit_continue;
 211 }
 212
 213 ir_visitor_status
 214 link_uniform_block_active_visitor::visit_enter(ir_dereference_array *ir)
 215 {
 216    /* cycle through arrays of arrays */
 217    ir_dereference_array *base_ir = ir;
 218    while (base_ir->array->ir_type == ir_type_dereference_array)
 219       base_ir = base_ir->array->as_dereference_array();
 220
 221    ir_dereference_variable *const d =
 222       base_ir->array->as_dereference_variable();
 223    ir_variable *const var = (d == NULL) ? NULL : d->var;
 224
 225    /* If the r-value being dereferenced is not a variable (e.g., a field of a
 226     * structure) or is not a uniform block instance, continue.
 227     *
 228     * WARNING: It is not enough for the variable to be part of uniform block.
 229     * It must represent the entire block.  Arrays (or matrices) inside blocks
 230     * that lack an instance name are handled by the ir_dereference_variable
 231     * function.
 232     */
 233    if (var == NULL
 234        || !var->is_in_buffer_block()
 235        || !var->is_interface_instance())
 236       return visit_continue;
 237
 238    /* Process the block.  Bail if there was an error. */
 239    link_uniform_block_active *const b =
 240       process_block(this->mem_ctx, this->ht, var);
 241    if (b == NULL) {
 242       linker_error(prog,
 243                    "uniform block `%s' has mismatching definitions",
 244                    var->get_interface_type()->name);
 245       this->success = false;
 246       return visit_stop;
 247    }
 248
 249    /* Block arrays must be declared with an instance name.
 250     */
 251    assert(b->has_instance_name);
 252    assert(b->type != NULL);
 253
 254    /* If the block array was declared with a shared or std140 layout
 255     * qualifier, all its instances have been already marked as used in
 256     * link_uniform_block_active_visitor::visit(ir_variable *).
 257     */
 258    if (var->get_interface_type_packing() == GLSL_INTERFACE_PACKING_PACKED) {
 259       b->var = var;
 260       process_arrays(this->mem_ctx, ir, b);
 261    }
 262
 263    return visit_continue_with_parent;
 264 }
 265
 266 ir_visitor_status
 267 link_uniform_block_active_visitor::visit(ir_dereference_variable *ir)
 268 {
 269    ir_variable *var = ir->var;
 270
 271    if (!var->is_in_buffer_block())
 272       return visit_continue;
 273
 274    assert(!var->is_interface_instance() || !var->type->is_array());
 275
 276    /* Process the block.  Bail if there was an error. */
 277    link_uniform_block_active *const b =
 278       process_block(this->mem_ctx, this->ht, var);
 279    if (b == NULL) {
 280       linker_error(this->prog,
 281                    "uniform block `%s' has mismatching definitions",
 282                    var->get_interface_type()->name);
 283       this->success = false;
 284       return visit_stop;
 285    }
 286
 287    assert(b->array == NULL);
 288    assert(b->type != NULL);
 289
 290    return visit_continue;
 291 }