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          (*ub_array_ptr)->aoa_size =
 107                       ir->array->type->arrays_of_arrays_size();
 108       }
 109
 110       struct uniform_block_array_elements *ub_array = *ub_array_ptr;
 111       ir_constant *c = ir->array_index->as_constant();
 112       if (c) {
 113          /* Index is a constant, so mark just that element used, if not
 114           * already.
 115           */
 116          const unsigned idx = c->get_uint_component(0);
 117
 118          unsigned i;
 119          for (i = 0; i < ub_array->num_array_elements; i++) {
 120             if (ub_array->array_elements[i] == idx)
 121                break;
 122          }
 123
 124          assert(i <= ub_array->num_array_elements);
 125
 126          if (i == ub_array->num_array_elements) {
 127             ub_array->array_elements = reralloc(mem_ctx,
 128                                                 ub_array->array_elements,
 129                                                 unsigned,
 130                                                 ub_array->num_array_elements + 1);
 131
 132             ub_array->array_elements[ub_array->num_array_elements] = idx;
 133
 134             ub_array->num_array_elements++;
 135          }
 136       } else {
 137          /* The array index is not a constant, so mark the entire array used. */
 138          assert(ir->array->type->is_array());
 139          if (ub_array->num_array_elements < ir->array->type->length) {
 140             ub_array->num_array_elements = ir->array->type->length;
 141             ub_array->array_elements = reralloc(mem_ctx,
 142                                                 ub_array->array_elements,
 143                                                 unsigned,
 144                                                 ub_array->num_array_elements);
 145
 146             for (unsigned i = 0; i < ub_array->num_array_elements; i++) {
 147                ub_array->array_elements[i] = i;
 148             }
 149          }
 150       }
 151
 152       return &ub_array->array;
 153    } else {
 154       return &block->array;
 155    }
 156 }
 157
 158 ir_visitor_status
 159 link_uniform_block_active_visitor::visit(ir_variable *var)
 160 {
 161    if (!var->is_in_buffer_block())
 162       return visit_continue;
 163
 164    /* Section 2.11.6 (Uniform Variables) of the OpenGL ES 3.0.3 spec says:
 165     *
 166     *     "All members of a named uniform block declared with a shared or
 167     *     std140 layout qualifier are considered active, even if they are not
 168     *     referenced in any shader in the program. The uniform block itself is
 169     *     also considered active, even if no member of the block is
 170     *     referenced."
 171     */
 172    if (var->get_interface_type_packing() == GLSL_INTERFACE_PACKING_PACKED)
 173       return visit_continue;
 174
 175    /* Process the block.  Bail if there was an error. */
 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       (*ub_array)->aoa_size = type->arrays_of_arrays_size();
 205
 206       for (unsigned i = 0; i < (*ub_array)->num_array_elements; i++) {
 207          (*ub_array)->array_elements[i] = i;
 208       }
 209       ub_array = &(*ub_array)->array;
 210       type = type->fields.array;
 211    }
 212
 213    return visit_continue;
 214 }
 215
 216 ir_visitor_status
 217 link_uniform_block_active_visitor::visit_enter(ir_dereference_array *ir)
 218 {
 219    /* cycle through arrays of arrays */
 220    ir_dereference_array *base_ir = ir;
 221    while (base_ir->array->ir_type == ir_type_dereference_array)
 222       base_ir = base_ir->array->as_dereference_array();
 223
 224    ir_dereference_variable *const d =
 225       base_ir->array->as_dereference_variable();
 226    ir_variable *const var = (d == NULL) ? NULL : d->var;
 227
 228    /* If the r-value being dereferenced is not a variable (e.g., a field of a
 229     * structure) or is not a uniform block instance, continue.
 230     *
 231     * WARNING: It is not enough for the variable to be part of uniform block.
 232     * It must represent the entire block.  Arrays (or matrices) inside blocks
 233     * that lack an instance name are handled by the ir_dereference_variable
 234     * function.
 235     */
 236    if (var == NULL
 237        || !var->is_in_buffer_block()
 238        || !var->is_interface_instance())
 239       return visit_continue;
 240
 241    /* Process the block.  Bail if there was an error. */
 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 std140 layout
 258     * qualifier, all its instances have been already marked as used in
 259     * link_uniform_block_active_visitor::visit(ir_variable *).
 260     */
 261    if (var->get_interface_type_packing() == GLSL_INTERFACE_PACKING_PACKED) {
 262       b->var = var;
 263       process_arrays(this->mem_ctx, ir, b);
 264    }
 265
 266    return visit_continue_with_parent;
 267 }
 268
 269 ir_visitor_status
 270 link_uniform_block_active_visitor::visit(ir_dereference_variable *ir)
 271 {
 272    ir_variable *var = ir->var;
 273
 274    if (!var->is_in_buffer_block())
 275       return visit_continue;
 276
 277    assert(!var->is_interface_instance() || !var->type->is_array());
 278
 279    /* Process the block.  Bail if there was an error. */
 280    link_uniform_block_active *const b =
 281       process_block(this->mem_ctx, this->ht, var);
 282    if (b == NULL) {
 283       linker_error(this->prog,
 284                    "uniform block `%s' has mismatching definitions",
 285                    var->get_interface_type()->name);
 286       this->success = false;
 287       return visit_stop;
 288    }
 289
 290    assert(b->array == NULL);
 291    assert(b->type != NULL);
 292
 293    return visit_continue;
 294 }