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 && mode != ir_var_uniform &&
 116        strcmp(a->instance_name, b->instance_name) != 0) {
 117       return false;
 118    }
 119
 120    /* If a block is an array then it must match across the shader.
 121     * Unsized arrays are also processed and matched agaist sized arrays.
 122     */
 123    if (b->var->type != a->var->type &&
 124        (b->instance_name != NULL || a->instance_name != NULL) &&
 125        !validate_intrastage_arrays(prog, b->var, a->var))
 126       return false;
 127
 128    return true;
 129 }
 130
 131
 132 /**
 133  * Check if two interfaces match, according to interstage (in/out) interface
 134  * matching rules.
 135  *
 136  * If \c extra_array_level is true, then vertex-to-geometry shader matching
 137  * rules are enforced (i.e. a successful match requires the consumer interface
 138  * to be an array and the producer interface to be a non-array).
 139  */
 140 bool
 141 interstage_match(const interface_block_definition *producer,
 142                  const interface_block_definition *consumer,
 143                  bool extra_array_level)
 144 {
 145    /* Unsized arrays should not occur during interstage linking.  They
 146     * should have all been assigned a size by link_intrastage_shaders.
 147     */
 148    assert(!consumer->var->type->is_unsized_array());
 149    assert(!producer->var->type->is_unsized_array());
 150
 151    /* Types must match. */
 152    if (consumer->type != producer->type) {
 153       /* Exception: if both the interface blocks are implicitly declared,
 154        * don't force their types to match.  They might mismatch due to the two
 155        * shaders using different GLSL versions, and that's ok.
 156        */
 157       if (consumer->explicitly_declared || producer->explicitly_declared)
 158          return false;
 159    }
 160
 161    /* Ignore outermost array if geom shader */
 162    const glsl_type *consumer_instance_type;
 163    if (extra_array_level) {
 164       consumer_instance_type = consumer->var->type->fields.array;
 165    } else {
 166       consumer_instance_type = consumer->var->type;
 167    }
 168
 169    /* If a block is an array then it must match across shaders.
 170     * Since unsized arrays have been ruled out, we can check this by just
 171     * making sure the types are equal.
 172     */
 173    if ((consumer->instance_name != NULL &&
 174         consumer_instance_type->is_array()) ||
 175        (producer->instance_name != NULL &&
 176         producer->var->type->is_array())) {
 177       if (consumer_instance_type != producer->var->type)
 178          return false;
 179    }
 180
 181    return true;
 182 }
 183
 184
 185 /**
 186  * This class keeps track of a mapping from an interface block name to the
 187  * necessary information about that interface block to determine whether to
 188  * generate a link error.
 189  *
 190  * Note: this class is expected to be short lived, so it doesn't make copies
 191  * of the strings it references; it simply borrows the pointers from the
 192  * ir_variable class.
 193  */
 194 class interface_block_definitions
 195 {
 196 public:
 197    interface_block_definitions()
 198       : mem_ctx(ralloc_context(NULL)),
 199         ht(hash_table_ctor(0, hash_table_string_hash,
 200                            hash_table_string_compare))
 201    {
 202    }
 203
 204    ~interface_block_definitions()
 205    {
 206       hash_table_dtor(ht);
 207       ralloc_free(mem_ctx);
 208    }
 209
 210    /**
 211     * Lookup the interface definition having the given block name.  Return
 212     * NULL if none is found.
 213     */
 214    interface_block_definition *lookup(const char *block_name)
 215    {
 216       return (interface_block_definition *) hash_table_find(ht, block_name);
 217    }
 218
 219    /**
 220     * Add a new interface definition.
 221     */
 222    void store(const interface_block_definition &def)
 223    {
 224       interface_block_definition *hash_entry =
 225          rzalloc(mem_ctx, interface_block_definition);
 226       *hash_entry = def;
 227       hash_table_insert(ht, hash_entry, def.type->name);
 228    }
 229
 230 private:
 231    /**
 232     * Ralloc context for data structures allocated by this class.
 233     */
 234    void *mem_ctx;
 235
 236    /**
 237     * Hash table mapping interface block name to an \c
 238     * interface_block_definition struct.  interface_block_definition structs
 239     * are allocated using \c mem_ctx.
 240     */
 241    hash_table *ht;
 242 };
 243
 244
 245 }; /* anonymous namespace */
 246
 247
 248 void
 249 validate_intrastage_interface_blocks(struct gl_shader_program *prog,
 250                                      const gl_shader **shader_list,
 251                                      unsigned num_shaders)
 252 {
 253    interface_block_definitions in_interfaces;
 254    interface_block_definitions out_interfaces;
 255    interface_block_definitions uniform_interfaces;
 256
 257    for (unsigned int i = 0; i < num_shaders; i++) {
 258       if (shader_list[i] == NULL)
 259          continue;
 260
 261       foreach_in_list(ir_instruction, node, shader_list[i]->ir) {
 262          ir_variable *var = node->as_variable();
 263          if (!var)
 264             continue;
 265
 266          const glsl_type *iface_type = var->get_interface_type();
 267
 268          if (iface_type == NULL)
 269             continue;
 270
 271          interface_block_definitions *definitions;
 272          switch (var->data.mode) {
 273          case ir_var_shader_in:
 274             definitions = &in_interfaces;
 275             break;
 276          case ir_var_shader_out:
 277             definitions = &out_interfaces;
 278             break;
 279          case ir_var_uniform:
 280             definitions = &uniform_interfaces;
 281             break;
 282          default:
 283             /* Only in, out, and uniform interfaces are legal, so we should
 284              * never get here.
 285              */
 286             assert(!"illegal interface type");
 287             continue;
 288          }
 289
 290          const interface_block_definition def(var);
 291          interface_block_definition *prev_def =
 292             definitions->lookup(iface_type->name);
 293
 294          if (prev_def == NULL) {
 295             /* This is the first time we've seen the interface, so save
 296              * it into the appropriate data structure.
 297              */
 298             definitions->store(def);
 299          } else if (!intrastage_match(prev_def, &def,
 300                                       (ir_variable_mode) var->data.mode,
 301                                       prog)) {
 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->Stage == MESA_SHADER_GEOMETRY;
 317
 318    /* Add input interfaces from the consumer to the symbol table. */
 319    foreach_in_list(ir_instruction, node, consumer->ir) {
 320       ir_variable *var = 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_in_list(ir_instruction, node, producer->ir) {
 329       ir_variable *var = 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_in_list(ir_instruction, node, stage->ir) {
 363          ir_variable *var = 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, prog)) {
 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 }