src/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
  27 static link_uniform_block_active *
  28 process_block(void *mem_ctx, struct hash_table *ht, ir_variable *var)
  29 {
  30    const hash_entry *const existing_block =
  31       _mesa_hash_table_search(ht, var->get_interface_type()->name);
  32
  33    const glsl_type *const block_type = var->is_interface_instance()
  34       ? var->type : var->get_interface_type();
  35
  36
  37    /* If a block with this block-name has not previously been seen, add it.
  38     * If a block with this block-name has been seen, it must be identical to
  39     * the block currently being examined.
  40     */
  41    if (existing_block == NULL) {
  42       link_uniform_block_active *const b =
  43          rzalloc(mem_ctx, struct link_uniform_block_active);
  44
  45       b->type = block_type;
  46       b->has_instance_name = var->is_interface_instance();
  47       b->is_shader_storage = var->data.mode == ir_var_shader_storage;
  48
  49       if (var->data.explicit_binding) {
  50          b->has_binding = true;
  51          b->binding = var->data.binding;
  52       } else {
  53          b->has_binding = false;
  54          b->binding = 0;
  55       }
  56
  57       _mesa_hash_table_insert(ht, var->get_interface_type()->name, (void *) b);
  58       return b;
  59    } else {
  60       link_uniform_block_active *const b =
  61          (link_uniform_block_active *) existing_block->data;
  62
  63       if (b->type != block_type
  64           || b->has_instance_name != var->is_interface_instance())
  65          return NULL;
  66       else
  67          return b;
  68    }
  69
  70    assert(!"Should not get here.");
  71    return NULL;
  72 }
  73
  74 /* For arrays of arrays this function will give us a middle ground between
  75  * detecting inactive uniform blocks and structuring them in a way that makes
  76  * it easy to calculate the offset for indirect indexing.
  77  *
  78  * For example given the shader:
  79  *
  80  *   uniform ArraysOfArraysBlock
  81  *   {
  82  *      vec4 a;
  83  *   } i[3][4][5];
  84  *
  85  *   void main()
  86  *   {
  87  *      vec4 b = i[0][1][1].a;
  88  *      gl_Position = i[2][2][3].a + b;
  89  *   }
  90  *
  91  * There are only 2 active blocks above but for the sake of indirect indexing
  92  * and not over complicating the code we will end up with a count of 8.
  93  * Here each dimension has 2 different indices counted so we end up with 2*2*2
  94  */
  95 static struct uniform_block_array_elements **
  96 process_arrays(void *mem_ctx, ir_dereference_array *ir,
  97                struct link_uniform_block_active *block)
  98 {
  99    if (ir) {
 100       struct uniform_block_array_elements **ub_array_ptr =
 101          process_arrays(mem_ctx, ir->array->as_dereference_array(), block);
 102       if (*ub_array_ptr == NULL) {
 103          *ub_array_ptr = rzalloc(mem_ctx, struct uniform_block_array_elements);
 104          (*ub_array_ptr)->ir = ir;
 105       }
 106
 107       struct uniform_block_array_elements *ub_array = *ub_array_ptr;
 108       ir_constant *c = ir->array_index->as_constant();
 109       if (c) {
 110          /* Index is a constant, so mark just that element used,
 111           * if not already.
 112           */
 113          const unsigned idx = c->get_uint_component(0);
 114
 115          unsigned i;
 116          for (i = 0; i < ub_array->num_array_elements; i++) {
 117             if (ub_array->array_elements[i] == idx)
 118                break;
 119          }
 120
 121          assert(i <= ub_array->num_array_elements);
 122
 123          if (i == ub_array->num_array_elements) {
 124             ub_array->array_elements = reralloc(mem_ctx,
 125                                                 ub_array->array_elements,
 126                                                 unsigned,
 127                                                 ub_array->num_array_elements + 1);
 128
 129             ub_array->array_elements[ub_array->num_array_elements] = idx;
 130
 131             ub_array->num_array_elements++;
 132          }
 133       } else {
 134          /* The array index is not a constant,
 135           * so mark the entire array used.
 136           */
 137          assert(ir->array->type->is_array());
 138          if (ub_array->num_array_elements < ir->array->type->length) {
 139             ub_array->num_array_elements = ir->array->type->length;
 140             ub_array->array_elements = reralloc(mem_ctx,
 141                                                 ub_array->array_elements,
 142                                                 unsigned,
 143                                                 ub_array->num_array_elements);
 144
 145             for (unsigned i = 0; i < ub_array->num_array_elements; i++) {
 146                ub_array->array_elements[i] = i;
 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()->interface_packing ==
 171        GLSL_INTERFACE_PACKING_PACKED)
 172       return visit_continue;
 173
 174    /* Process the block.  Bail if there was an error.
 175     */
 176    link_uniform_block_active *const b =
 177       process_block(this->mem_ctx, this->ht, var);
 178    if (b == NULL) {
 179       linker_error(this->prog,
 180                    "uniform block `%s' has mismatching definitions",
 181                    var->get_interface_type()->name);
 182       this->success = false;
 183       return visit_stop;
 184    }
 185
 186    assert(b->array == NULL);
 187    assert(b->type != NULL);
 188    assert(!b->type->is_array() || b->has_instance_name);
 189
 190    /* For uniform block arrays declared with a shared or std140 layout
 191     * qualifier, mark all its instances as used.
 192     */
 193    const glsl_type *type = b->type;
 194    struct uniform_block_array_elements **ub_array = &b->array;
 195    while (type->is_array()) {
 196       assert(b->type->length > 0);
 197
 198       *ub_array = rzalloc(this->mem_ctx, struct uniform_block_array_elements);
 199       (*ub_array)->num_array_elements = type->length;
 200       (*ub_array)->array_elements = reralloc(this->mem_ctx,
 201                                              (*ub_array)->array_elements,
 202                                              unsigned,
 203                                              (*ub_array)->num_array_elements);
 204
 205       for (unsigned i = 0; i < (*ub_array)->num_array_elements; i++) {
 206          (*ub_array)->array_elements[i] = i;
 207       }
 208       ub_array = &(*ub_array)->array;
 209       type = type->fields.array;
 210    }
 211
 212    return visit_continue;
 213 }
 214
 215 ir_visitor_status
 216 link_uniform_block_active_visitor::visit_enter(ir_dereference_array *ir)
 217 {
 218    /* cycle through arrays of arrays */
 219    ir_dereference_array *base_ir = ir;
 220    while (base_ir->array->ir_type == ir_type_dereference_array)
 221       base_ir = base_ir->array->as_dereference_array();
 222
 223    ir_dereference_variable *const d =
 224       base_ir->array->as_dereference_variable();
 225    ir_variable *const var = (d == NULL) ? NULL : d->var;
 226
 227    /* If the r-value being dereferenced is not a variable (e.g., a field of a
 228     * structure) or is not a uniform block instance, continue.
 229     *
 230     * WARNING: It is not enough for the variable to be part of uniform block.
 231     * It must represent the entire block.  Arrays (or matrices) inside blocks
 232     * that lack an instance name are handled by the ir_dereference_variable
 233     * function.
 234     */
 235    if (var == NULL
 236        || !var->is_in_buffer_block()
 237        || !var->is_interface_instance())
 238       return visit_continue;
 239
 240    /* Process the block.  Bail if there was an error.
 241     */
 242    link_uniform_block_active *const b =
 243       process_block(this->mem_ctx, this->ht, var);
 244    if (b == NULL) {
 245       linker_error(prog,
 246                    "uniform block `%s' has mismatching definitions",
 247                    var->get_interface_type()->name);
 248       this->success = false;
 249       return visit_stop;
 250    }
 251
 252    /* Block arrays must be declared with an instance name.
 253     */
 254    assert(b->has_instance_name);
 255    assert(b->type != NULL);
 256
 257    /* If the block array was declared with a shared or
 258     * std140 layout qualifier, all its instances have been already marked
 259     * as used in link_uniform_block_active_visitor::visit(ir_variable *).
 260     */
 261    if (var->get_interface_type()->interface_packing ==
 262        GLSL_INTERFACE_PACKING_PACKED) {
 263       b->var = var;
 264       process_arrays(this->mem_ctx, ir, b);
 265    }
 266
 267    return visit_continue_with_parent;
 268 }
 269
 270 ir_visitor_status
 271 link_uniform_block_active_visitor::visit(ir_dereference_variable *ir)
 272 {
 273    ir_variable *var = ir->var;
 274
 275    if (!var->is_in_buffer_block())
 276       return visit_continue;
 277
 278    assert(!var->is_interface_instance() || !var->type->is_array());
 279
 280    /* Process the block.  Bail if there was an error.
 281     */
 282    link_uniform_block_active *const b =
 283       process_block(this->mem_ctx, this->ht, var);
 284    if (b == NULL) {
 285       linker_error(this->prog,
 286                    "uniform block `%s' has mismatching definitions",
 287                    var->get_interface_type()->name);
 288       this->success = false;
 289       return visit_stop;
 290    }
 291
 292    assert(b->array == NULL);
 293    assert(b->type != NULL);
 294
 295    return visit_continue;
 296 }