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    }
  64
  65    /**
  66     * Interface block type
  67     */
  68    const glsl_type *type;
  69
  70    /**
  71     * For a named interface block, the instance name.  Otherwise NULL.
  72     */
  73    const char *instance_name;
  74
  75    /**
  76     * For an interface block array, the array size (or 0 if unsized).
  77     * Otherwise -1.
  78     */
  79    int array_size;
  80 };
  81
  82
  83 /**
  84  * Check if two interfaces match, according to intrastage interface matching
  85  * rules.  If they do, and the first interface uses an unsized array, it will
  86  * be updated to reflect the array size declared in the second interface.
  87  */
  88 bool
  89 intrastage_match(interface_block_definition *a,
  90                  const interface_block_definition *b,
  91                  ir_variable_mode mode)
  92 {
  93    /* Types must match. */
  94    if (a->type != b->type)
  95       return false;
  96
  97    /* Presence/absence of interface names must match. */
  98    if ((a->instance_name == NULL) != (b->instance_name == NULL))
  99       return false;
 100
 101    /* For uniforms, instance names need not match.  For shader ins/outs,
 102     * it's not clear from the spec whether they need to match, but
 103     * Mesa's implementation relies on them matching.
 104     */
 105    if (a->instance_name != NULL && mode != ir_var_uniform &&
 106        strcmp(a->instance_name, b->instance_name) != 0) {
 107       return false;
 108    }
 109
 110    /* Array vs. nonarray must be consistent, and sizes must be
 111     * consistent, with the exception that unsized arrays match sized
 112     * arrays.
 113     */
 114    if ((a->array_size == -1) != (b->array_size == -1))
 115       return false;
 116    if (b->array_size != 0) {
 117       if (a->array_size == 0)
 118          a->array_size = b->array_size;
 119       else if (a->array_size != b->array_size)
 120          return false;
 121    }
 122
 123    return true;
 124 }
 125
 126
 127 /**
 128  * Check if two interfaces match, according to interstage (in/out) interface
 129  * matching rules.
 130  *
 131  * If \c extra_array_level is true, then vertex-to-geometry shader matching
 132  * rules are enforced (i.e. a successful match requires the consumer interface
 133  * to be an array and the producer interface to be a non-array).
 134  */
 135 bool
 136 interstage_match(const interface_block_definition *producer,
 137                  const interface_block_definition *consumer,
 138                  bool extra_array_level)
 139 {
 140    /* Unsized arrays should not occur during interstage linking.  They
 141     * should have all been assigned a size by link_intrastage_shaders.
 142     */
 143    assert(consumer->array_size != 0);
 144    assert(producer->array_size != 0);
 145
 146    /* Types must match. */
 147    if (consumer->type != producer->type)
 148       return false;
 149    if (extra_array_level) {
 150       /* Consumer must be an array, and producer must not. */
 151       if (consumer->array_size == -1)
 152          return false;
 153       if (producer->array_size != -1)
 154          return false;
 155    } else {
 156       /* Array vs. nonarray must be consistent, and sizes must be consistent.
 157        * Since unsized arrays have been ruled out, we can check this by just
 158        * making sure the sizes are equal.
 159        */
 160       if (consumer->array_size != producer->array_size)
 161          return false;
 162    }
 163    return true;
 164 }
 165
 166
 167 /**
 168  * This class keeps track of a mapping from an interface block name to the
 169  * necessary information about that interface block to determine whether to
 170  * generate a link error.
 171  *
 172  * Note: this class is expected to be short lived, so it doesn't make copies
 173  * of the strings it references; it simply borrows the pointers from the
 174  * ir_variable class.
 175  */
 176 class interface_block_definitions
 177 {
 178 public:
 179    interface_block_definitions()
 180       : mem_ctx(ralloc_context(NULL)),
 181         ht(hash_table_ctor(0, hash_table_string_hash,
 182                            hash_table_string_compare))
 183    {
 184    }
 185
 186    ~interface_block_definitions()
 187    {
 188       hash_table_dtor(ht);
 189       ralloc_free(mem_ctx);
 190    }
 191
 192    /**
 193     * Lookup the interface definition having the given block name.  Return
 194     * NULL if none is found.
 195     */
 196    interface_block_definition *lookup(const char *block_name)
 197    {
 198       return (interface_block_definition *) hash_table_find(ht, block_name);
 199    }
 200
 201    /**
 202     * Add a new interface definition.
 203     */
 204    void store(const interface_block_definition &def)
 205    {
 206       interface_block_definition *hash_entry =
 207          rzalloc(mem_ctx, interface_block_definition);
 208       *hash_entry = def;
 209       hash_table_insert(ht, hash_entry, def.type->name);
 210    }
 211
 212 private:
 213    /**
 214     * Ralloc context for data structures allocated by this class.
 215     */
 216    void *mem_ctx;
 217
 218    /**
 219     * Hash table mapping interface block name to an \c
 220     * interface_block_definition struct.  interface_block_definition structs
 221     * are allocated using \c mem_ctx.
 222     */
 223    hash_table *ht;
 224 };
 225
 226
 227 }; /* anonymous namespace */
 228
 229
 230 void
 231 validate_intrastage_interface_blocks(struct gl_shader_program *prog,
 232                                      const gl_shader **shader_list,
 233                                      unsigned num_shaders)
 234 {
 235    interface_block_definitions in_interfaces;
 236    interface_block_definitions out_interfaces;
 237    interface_block_definitions uniform_interfaces;
 238
 239    for (unsigned int i = 0; i < num_shaders; i++) {
 240       if (shader_list[i] == NULL)
 241          continue;
 242
 243       foreach_list(node, shader_list[i]->ir) {
 244          ir_variable *var = ((ir_instruction *) node)->as_variable();
 245          if (!var)
 246             continue;
 247
 248          const glsl_type *iface_type = var->get_interface_type();
 249
 250          if (iface_type == NULL)
 251             continue;
 252
 253          interface_block_definitions *definitions;
 254          switch (var->mode) {
 255          case ir_var_shader_in:
 256             definitions = &in_interfaces;
 257             break;
 258          case ir_var_shader_out:
 259             definitions = &out_interfaces;
 260             break;
 261          case ir_var_uniform:
 262             definitions = &uniform_interfaces;
 263             break;
 264          default:
 265             /* Only in, out, and uniform interfaces are legal, so we should
 266              * never get here.
 267              */
 268             assert(!"illegal interface type");
 269             continue;
 270          }
 271
 272          const interface_block_definition def(var);
 273          interface_block_definition *prev_def =
 274             definitions->lookup(iface_type->name);
 275
 276          if (prev_def == NULL) {
 277             /* This is the first time we've seen the interface, so save
 278              * it into the appropriate data structure.
 279              */
 280             definitions->store(def);
 281          } else if (!intrastage_match(prev_def, &def,
 282                                       (ir_variable_mode) var->mode)) {
 283             linker_error(prog, "definitions of interface block `%s' do not"
 284                          " match\n", iface_type->name);
 285             return;
 286          }
 287       }
 288    }
 289 }
 290
 291 void
 292 validate_interstage_interface_blocks(struct gl_shader_program *prog,
 293                                      const gl_shader *producer,
 294                                      const gl_shader *consumer)
 295 {
 296    interface_block_definitions inout_interfaces;
 297    interface_block_definitions uniform_interfaces;
 298    const bool extra_array_level = consumer->Type == GL_GEOMETRY_SHADER;
 299
 300    /* Add non-output interfaces from the consumer to the symbol table. */
 301    foreach_list(node, consumer->ir) {
 302       ir_variable *var = ((ir_instruction *) node)->as_variable();
 303       if (!var || !var->get_interface_type() || var->mode == ir_var_shader_out)
 304          continue;
 305
 306       interface_block_definitions *definitions = var->mode == ir_var_uniform ?
 307          &uniform_interfaces : &inout_interfaces;
 308       definitions->store(interface_block_definition(var));
 309    }
 310
 311    /* Verify that the producer's interfaces match. */
 312    foreach_list(node, producer->ir) {
 313       ir_variable *var = ((ir_instruction *) node)->as_variable();
 314       if (!var || !var->get_interface_type() || var->mode == ir_var_shader_in)
 315          continue;
 316
 317       interface_block_definitions *definitions = var->mode == ir_var_uniform ?
 318          &uniform_interfaces : &inout_interfaces;
 319       interface_block_definition *consumer_def =
 320          definitions->lookup(var->get_interface_type()->name);
 321
 322       /* The consumer doesn't use this output block.  Ignore it. */
 323       if (consumer_def == NULL)
 324          continue;
 325
 326       const interface_block_definition producer_def(var);
 327       bool match;
 328       if (var->mode == ir_var_uniform) {
 329          /* Uniform matching rules are the same for interstage and intrastage
 330           * linking.
 331           */
 332          match = intrastage_match(consumer_def, &producer_def,
 333                                   (ir_variable_mode) var->mode);
 334       } else {
 335          match = interstage_match(&producer_def, consumer_def,
 336                                   extra_array_level);
 337       }
 338
 339       if (!match) {
 340          linker_error(prog, "definitions of interface block `%s' do not "
 341                       "match\n", var->get_interface_type()->name);
 342          return;
 343       }
 344    }
 345 }