src/glsl/link_interface_blocks.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 /**
  25  * \file link_interface_blocks.cpp
  26  * Linker support for GLSL's interface blocks.
  27  */
  28
  29 #include "ir.h"
  30 #include "glsl_symbol_table.h"
  31 #include "linker.h"
  32 #include "main/macros.h"
  33 #include "program/hash_table.h"
  34
  35
  36 namespace {
  37
  38 /**
  39  * Information about a single interface block definition that we need to keep
  40  * track of in order to check linkage rules.
  41  *
  42  * Note: this class is expected to be short lived, so it doesn't make copies
  43  * of the strings it references; it simply borrows the pointers from the
  44  * ir_variable class.
  45  */
  46 struct interface_block_definition
  47 {
  48    /**
  49     * Extract an interface block definition from an ir_variable that
  50     * represents either the interface instance (for named interfaces), or a
  51     * member of the interface (for unnamed interfaces).
  52     */
  53    explicit interface_block_definition(ir_variable *var)
  54       : var(var),
  55         type(var->get_interface_type()),
  56         instance_name(NULL)
  57    {
  58       if (var->is_interface_instance()) {
  59          instance_name = var->name;
  60       }
  61       explicitly_declared = (var->data.how_declared != ir_var_declared_implicitly);
  62    }
  63    /**
  64     * Interface block ir_variable
  65     */
  66    ir_variable *var;
  67
  68    /**
  69     * Interface block type
  70     */
  71    const glsl_type *type;
  72
  73    /**
  74     * For a named interface block, the instance name.  Otherwise NULL.
  75     */
  76    const char *instance_name;
  77
  78    /**
  79     * True if this interface block was explicitly declared in the shader;
  80     * false if it was an implicitly declared built-in interface block.
  81     */
  82    bool explicitly_declared;
  83 };
  84
  85
  86 /**
  87  * Check if two interfaces match, according to intrastage interface matching
  88  * rules.  If they do, and the first interface uses an unsized array, it will
  89  * be updated to reflect the array size declared in the second interface.
  90  */
  91 bool
  92 intrastage_match(interface_block_definition *a,
  93                  const interface_block_definition *b,
  94                  ir_variable_mode mode,
  95                  struct gl_shader_program *prog)
  96 {
  97    /* Types must match. */
  98    if (a->type != b->type) {
  99       /* Exception: if both the interface blocks are implicitly declared,
 100        * don't force their types to match.  They might mismatch due to the two
 101        * shaders using different GLSL versions, and that's ok.
 102        */
 103       if (a->explicitly_declared || b->explicitly_declared)
 104          return false;
 105    }
 106
 107    /* Presence/absence of interface names must match. */
 108    if ((a->instance_name == NULL) != (b->instance_name == NULL))
 109       return false;
 110
 111    /* For uniforms, instance names need not match.  For shader ins/outs,
 112     * it's not clear from the spec whether they need to match, but
 113     * Mesa's implementation relies on them matching.
 114     */
 115    if (a->instance_name != NULL &&
 116        mode != ir_var_uniform && mode != ir_var_shader_storage &&
 117        strcmp(a->instance_name, b->instance_name) != 0) {
 118       return false;
 119    }
 120
 121    /* If a block is an array then it must match across the shader.
 122     * Unsized arrays are also processed and matched agaist sized arrays.
 123     */
 124    if (b->var->type != a->var->type &&
 125        (b->instance_name != NULL || a->instance_name != NULL) &&
 126        !validate_intrastage_arrays(prog, b->var, a->var))
 127       return false;
 128
 129    return true;
 130 }
 131
 132
 133 /**
 134  * Check if two interfaces match, according to interstage (in/out) interface
 135  * matching rules.
 136  *
 137  * If \c extra_array_level is true, then vertex-to-geometry shader matching
 138  * rules are enforced (i.e. a successful match requires the consumer interface
 139  * to be an array and the producer interface to be a non-array).
 140  */
 141 bool
 142 interstage_match(const interface_block_definition *producer,
 143                  const interface_block_definition *consumer,
 144                  bool extra_array_level)
 145 {
 146    /* Unsized arrays should not occur during interstage linking.  They
 147     * should have all been assigned a size by link_intrastage_shaders.
 148     */
 149    assert(!consumer->var->type->is_unsized_array());
 150    assert(!producer->var->type->is_unsized_array());
 151
 152    /* Types must match. */
 153    if (consumer->type != producer->type) {
 154       /* Exception: if both the interface blocks are implicitly declared,
 155        * don't force their types to match.  They might mismatch due to the two
 156        * shaders using different GLSL versions, and that's ok.
 157        */
 158       if (consumer->explicitly_declared || producer->explicitly_declared)
 159          return false;
 160    }
 161
 162    /* Ignore outermost array if geom shader */
 163    const glsl_type *consumer_instance_type;
 164    if (extra_array_level) {
 165       consumer_instance_type = consumer->var->type->fields.array;
 166    } else {
 167       consumer_instance_type = consumer->var->type;
 168    }
 169
 170    /* If a block is an array then it must match across shaders.
 171     * Since unsized arrays have been ruled out, we can check this by just
 172     * making sure the types are equal.
 173     */
 174    if ((consumer->instance_name != NULL &&
 175         consumer_instance_type->is_array()) ||
 176        (producer->instance_name != NULL &&
 177         producer->var->type->is_array())) {
 178       if (consumer_instance_type != producer->var->type)
 179          return false;
 180    }
 181
 182    return true;
 183 }
 184
 185
 186 /**
 187  * This class keeps track of a mapping from an interface block name to the
 188  * necessary information about that interface block to determine whether to
 189  * generate a link error.
 190  *
 191  * Note: this class is expected to be short lived, so it doesn't make copies
 192  * of the strings it references; it simply borrows the pointers from the
 193  * ir_variable class.
 194  */
 195 class interface_block_definitions
 196 {
 197 public:
 198    interface_block_definitions()
 199       : mem_ctx(ralloc_context(NULL)),
 200         ht(hash_table_ctor(0, hash_table_string_hash,
 201                            hash_table_string_compare))
 202    {
 203    }
 204
 205    ~interface_block_definitions()
 206    {
 207       hash_table_dtor(ht);
 208       ralloc_free(mem_ctx);
 209    }
 210
 211    /**
 212     * Lookup the interface definition having the given block name.  Return
 213     * NULL if none is found.
 214     */
 215    interface_block_definition *lookup(const char *block_name)
 216    {
 217       return (interface_block_definition *) hash_table_find(ht, block_name);
 218    }
 219
 220    /**
 221     * Add a new interface definition.
 222     */
 223    void store(const interface_block_definition &def)
 224    {
 225       interface_block_definition *hash_entry =
 226          rzalloc(mem_ctx, interface_block_definition);
 227       *hash_entry = def;
 228       hash_table_insert(ht, hash_entry, def.type->name);
 229    }
 230
 231 private:
 232    /**
 233     * Ralloc context for data structures allocated by this class.
 234     */
 235    void *mem_ctx;
 236
 237    /**
 238     * Hash table mapping interface block name to an \c
 239     * interface_block_definition struct.  interface_block_definition structs
 240     * are allocated using \c mem_ctx.
 241     */
 242    hash_table *ht;
 243 };
 244
 245
 246 }; /* anonymous namespace */
 247
 248
 249 void
 250 validate_intrastage_interface_blocks(struct gl_shader_program *prog,
 251                                      const gl_shader **shader_list,
 252                                      unsigned num_shaders)
 253 {
 254    interface_block_definitions in_interfaces;
 255    interface_block_definitions out_interfaces;
 256    interface_block_definitions uniform_interfaces;
 257    interface_block_definitions buffer_interfaces;
 258
 259    for (unsigned int i = 0; i < num_shaders; i++) {
 260       if (shader_list[i] == NULL)
 261          continue;
 262
 263       foreach_in_list(ir_instruction, node, shader_list[i]->ir) {
 264          ir_variable *var = node->as_variable();
 265          if (!var)
 266             continue;
 267
 268          const glsl_type *iface_type = var->get_interface_type();
 269
 270          if (iface_type == NULL)
 271             continue;
 272
 273          interface_block_definitions *definitions;
 274          switch (var->data.mode) {
 275          case ir_var_shader_in:
 276             definitions = &in_interfaces;
 277             break;
 278          case ir_var_shader_out:
 279             definitions = &out_interfaces;
 280             break;
 281          case ir_var_uniform:
 282             definitions = &uniform_interfaces;
 283             break;
 284          case ir_var_shader_storage:
 285             definitions = &buffer_interfaces;
 286             break;
 287          default:
 288             /* Only in, out, and uniform interfaces are legal, so we should
 289              * never get here.
 290              */
 291             assert(!"illegal interface type");
 292             continue;
 293          }
 294
 295          const interface_block_definition def(var);
 296          interface_block_definition *prev_def =
 297             definitions->lookup(iface_type->name);
 298
 299          if (prev_def == NULL) {
 300             /* This is the first time we've seen the interface, so save
 301              * it into the appropriate data structure.
 302              */
 303             definitions->store(def);
 304          } else if (!intrastage_match(prev_def, &def,
 305                                       (ir_variable_mode) var->data.mode,
 306                                       prog)) {
 307             linker_error(prog, "definitions of interface block `%s' do not"
 308                          " match\n", iface_type->name);
 309             return;
 310          }
 311       }
 312    }
 313 }
 314
 315 void
 316 validate_interstage_inout_blocks(struct gl_shader_program *prog,
 317                                  const gl_shader *producer,
 318                                  const gl_shader *consumer)
 319 {
 320    interface_block_definitions definitions;
 321    const bool extra_array_level = consumer->Stage == MESA_SHADER_GEOMETRY;
 322
 323    /* Add input interfaces from the consumer to the symbol table. */
 324    foreach_in_list(ir_instruction, node, consumer->ir) {
 325       ir_variable *var = node->as_variable();
 326       if (!var || !var->get_interface_type() || var->data.mode != ir_var_shader_in)
 327          continue;
 328
 329       definitions.store(interface_block_definition(var));
 330    }
 331
 332    /* Verify that the producer's output interfaces match. */
 333    foreach_in_list(ir_instruction, node, producer->ir) {
 334       ir_variable *var = node->as_variable();
 335       if (!var || !var->get_interface_type() || var->data.mode != ir_var_shader_out)
 336          continue;
 337
 338       interface_block_definition *consumer_def =
 339          definitions.lookup(var->get_interface_type()->name);
 340
 341       /* The consumer doesn't use this output block.  Ignore it. */
 342       if (consumer_def == NULL)
 343          continue;
 344
 345       const interface_block_definition producer_def(var);
 346
 347       if (!interstage_match(&producer_def, consumer_def, extra_array_level)) {
 348          linker_error(prog, "definitions of interface block `%s' do not "
 349                       "match\n", var->get_interface_type()->name);
 350          return;
 351       }
 352    }
 353 }
 354
 355
 356 void
 357 validate_interstage_uniform_blocks(struct gl_shader_program *prog,
 358                                    gl_shader **stages, int num_stages)
 359 {
 360    interface_block_definitions definitions;
 361
 362    for (int i = 0; i < num_stages; i++) {
 363       if (stages[i] == NULL)
 364          continue;
 365
 366       const gl_shader *stage = stages[i];
 367       foreach_in_list(ir_instruction, node, stage->ir) {
 368          ir_variable *var = node->as_variable();
 369          if (!var || !var->get_interface_type() ||
 370              (var->data.mode != ir_var_uniform &&
 371               var->data.mode != ir_var_shader_storage))
 372             continue;
 373
 374          interface_block_definition *old_def =
 375             definitions.lookup(var->get_interface_type()->name);
 376          const interface_block_definition new_def(var);
 377          if (old_def == NULL) {
 378             definitions.store(new_def);
 379          } else {
 380             /* Interstage uniform matching rules are the same as intrastage
 381              * uniform matchin rules (for uniforms, it is as though all
 382              * shaders are in the same shader stage).
 383              */
 384             if (!intrastage_match(old_def, &new_def,
 385                                   (ir_variable_mode) var->data.mode,
 386                                   prog)) {
 387                linker_error(prog, "definitions of interface block `%s' do not "
 388                             "match\n", var->get_interface_type()->name);
 389                return;
 390             }
 391          }
 392       }
 393    }
 394 }