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(const ir_variable *var)
  54       : type(var->get_interface_type()),
  55         instance_name(NULL),
  56         array_size(-1)
  57    {
  58       if (var->is_interface_instance()) {
  59          instance_name = var->name;
  60          if (var->type->is_array())
  61             array_size = var->type->length;
  62       }
  63       explicitly_declared = (var->data.how_declared != ir_var_declared_implicitly);
  64    }
  65
  66    /**
  67     * Interface block type
  68     */
  69    const glsl_type *type;
  70
  71    /**
  72     * For a named interface block, the instance name.  Otherwise NULL.
  73     */
  74    const char *instance_name;
  75
  76    /**
  77     * For an interface block array, the array size (or 0 if unsized).
  78     * Otherwise -1.
  79     */
  80    int array_size;
  81
  82    /**
  83     * True if this interface block was explicitly declared in the shader;
  84     * false if it was an implicitly declared built-in interface block.
  85     */
  86    bool explicitly_declared;
  87 };
  88
  89
  90 /**
  91  * Check if two interfaces match, according to intrastage interface matching
  92  * rules.  If they do, and the first interface uses an unsized array, it will
  93  * be updated to reflect the array size declared in the second interface.
  94  */
  95 bool
  96 intrastage_match(interface_block_definition *a,
  97                  const interface_block_definition *b,
  98                  ir_variable_mode mode)
  99 {
 100    /* Types must match. */
 101    if (a->type != b->type) {
 102       /* Exception: if both the interface blocks are implicitly declared,
 103        * don't force their types to match.  They might mismatch due to the two
 104        * shaders using different GLSL versions, and that's ok.
 105        */
 106       if (a->explicitly_declared || b->explicitly_declared)
 107          return false;
 108    }
 109
 110    /* Presence/absence of interface names must match. */
 111    if ((a->instance_name == NULL) != (b->instance_name == NULL))
 112       return false;
 113
 114    /* For uniforms, instance names need not match.  For shader ins/outs,
 115     * it's not clear from the spec whether they need to match, but
 116     * Mesa's implementation relies on them matching.
 117     */
 118    if (a->instance_name != NULL && mode != ir_var_uniform &&
 119        strcmp(a->instance_name, b->instance_name) != 0) {
 120       return false;
 121    }
 122
 123    /* Array vs. nonarray must be consistent, and sizes must be
 124     * consistent, with the exception that unsized arrays match sized
 125     * arrays.
 126     */
 127    if ((a->array_size == -1) != (b->array_size == -1))
 128       return false;
 129    if (b->array_size != 0) {
 130       if (a->array_size == 0)
 131          a->array_size = b->array_size;
 132       else if (a->array_size != b->array_size)
 133          return false;
 134    }
 135
 136    return true;
 137 }
 138
 139
 140 /**
 141  * Check if two interfaces match, according to interstage (in/out) interface
 142  * matching rules.
 143  *
 144  * If \c extra_array_level is true, then vertex-to-geometry shader matching
 145  * rules are enforced (i.e. a successful match requires the consumer interface
 146  * to be an array and the producer interface to be a non-array).
 147  */
 148 bool
 149 interstage_match(const interface_block_definition *producer,
 150                  const interface_block_definition *consumer,
 151                  bool extra_array_level)
 152 {
 153    /* Unsized arrays should not occur during interstage linking.  They
 154     * should have all been assigned a size by link_intrastage_shaders.
 155     */
 156    assert(consumer->array_size != 0);
 157    assert(producer->array_size != 0);
 158
 159    /* Types must match. */
 160    if (consumer->type != producer->type) {
 161       /* Exception: if both the interface blocks are implicitly declared,
 162        * don't force their types to match.  They might mismatch due to the two
 163        * shaders using different GLSL versions, and that's ok.
 164        */
 165       if (consumer->explicitly_declared || producer->explicitly_declared)
 166          return false;
 167    }
 168    if (extra_array_level) {
 169       /* Consumer must be an array, and producer must not. */
 170       if (consumer->array_size == -1)
 171          return false;
 172       if (producer->array_size != -1)
 173          return false;
 174    } else {
 175       /* Array vs. nonarray must be consistent, and sizes must be consistent.
 176        * Since unsized arrays have been ruled out, we can check this by just
 177        * making sure the sizes are equal.
 178        */
 179       if (consumer->array_size != producer->array_size)
 180          return false;
 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
 258    for (unsigned int i = 0; i < num_shaders; i++) {
 259       if (shader_list[i] == NULL)
 260          continue;
 261
 262       foreach_list(node, shader_list[i]->ir) {
 263          ir_variable *var = ((ir_instruction *) node)->as_variable();
 264          if (!var)
 265             continue;
 266
 267          const glsl_type *iface_type = var->get_interface_type();
 268
 269          if (iface_type == NULL)
 270             continue;
 271
 272          interface_block_definitions *definitions;
 273          switch (var->data.mode) {
 274          case ir_var_shader_in:
 275             definitions = &in_interfaces;
 276             break;
 277          case ir_var_shader_out:
 278             definitions = &out_interfaces;
 279             break;
 280          case ir_var_uniform:
 281             definitions = &uniform_interfaces;
 282             break;
 283          default:
 284             /* Only in, out, and uniform interfaces are legal, so we should
 285              * never get here.
 286              */
 287             assert(!"illegal interface type");
 288             continue;
 289          }
 290
 291          const interface_block_definition def(var);
 292          interface_block_definition *prev_def =
 293             definitions->lookup(iface_type->name);
 294
 295          if (prev_def == NULL) {
 296             /* This is the first time we've seen the interface, so save
 297              * it into the appropriate data structure.
 298              */
 299             definitions->store(def);
 300          } else if (!intrastage_match(prev_def, &def,
 301                                       (ir_variable_mode) var->data.mode)) {
 302             linker_error(prog, "definitions of interface block `%s' do not"
 303                          " match\n", iface_type->name);
 304             return;
 305          }
 306       }
 307    }
 308 }
 309
 310 void
 311 validate_interstage_inout_blocks(struct gl_shader_program *prog,
 312                                  const gl_shader *producer,
 313                                  const gl_shader *consumer)
 314 {
 315    interface_block_definitions definitions;
 316    const bool extra_array_level = consumer->Type == GL_GEOMETRY_SHADER;
 317
 318    /* Add input interfaces from the consumer to the symbol table. */
 319    foreach_list(node, consumer->ir) {
 320       ir_variable *var = ((ir_instruction *) node)->as_variable();
 321       if (!var || !var->get_interface_type() || var->data.mode != ir_var_shader_in)
 322          continue;
 323
 324       definitions.store(interface_block_definition(var));
 325    }
 326
 327    /* Verify that the producer's output interfaces match. */
 328    foreach_list(node, producer->ir) {
 329       ir_variable *var = ((ir_instruction *) node)->as_variable();
 330       if (!var || !var->get_interface_type() || var->data.mode != ir_var_shader_out)
 331          continue;
 332
 333       interface_block_definition *consumer_def =
 334          definitions.lookup(var->get_interface_type()->name);
 335
 336       /* The consumer doesn't use this output block.  Ignore it. */
 337       if (consumer_def == NULL)
 338          continue;
 339
 340       const interface_block_definition producer_def(var);
 341
 342       if (!interstage_match(&producer_def, consumer_def, extra_array_level)) {
 343          linker_error(prog, "definitions of interface block `%s' do not "
 344                       "match\n", var->get_interface_type()->name);
 345          return;
 346       }
 347    }
 348 }
 349
 350
 351 void
 352 validate_interstage_uniform_blocks(struct gl_shader_program *prog,
 353                                    gl_shader **stages, int num_stages)
 354 {
 355    interface_block_definitions definitions;
 356
 357    for (int i = 0; i < num_stages; i++) {
 358       if (stages[i] == NULL)
 359          continue;
 360
 361       const gl_shader *stage = stages[i];
 362       foreach_list(node, stage->ir) {
 363          ir_variable *var = ((ir_instruction *) node)->as_variable();
 364          if (!var || !var->get_interface_type() || var->data.mode != ir_var_uniform)
 365             continue;
 366
 367          interface_block_definition *old_def =
 368             definitions.lookup(var->get_interface_type()->name);
 369          const interface_block_definition new_def(var);
 370          if (old_def == NULL) {
 371             definitions.store(new_def);
 372          } else {
 373             /* Interstage uniform matching rules are the same as intrastage
 374              * uniform matchin rules (for uniforms, it is as though all
 375              * shaders are in the same shader stage).
 376              */
 377             if (!intrastage_match(old_def, &new_def, ir_var_uniform)) {
 378                linker_error(prog, "definitions of interface block `%s' do not "
 379                             "match\n", var->get_interface_type()->name);
 380                return;
 381             }
 382          }
 383       }
 384    }
 385 }