src/glsl/ir_reader.cpp

   1 /*
   2  * Copyright © 2010 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 <cstdarg>
  25
  26 extern "C" {
  27 #include <talloc.h>
  28 }
  29
  30 #include "ir_reader.h"
  31 #include "glsl_parser_extras.h"
  32 #include "glsl_types.h"
  33 #include "s_expression.h"
  34
  35 static void ir_read_error(_mesa_glsl_parse_state *, s_expression *,
  36                           const char *fmt, ...);
  37 static const glsl_type *read_type(_mesa_glsl_parse_state *, s_expression *);
  38
  39 static void scan_for_prototypes(_mesa_glsl_parse_state *, exec_list *,
  40                                 s_expression *);
  41 static ir_function *read_function(_mesa_glsl_parse_state *, s_list *,
  42                                   bool skip_body);
  43 static void read_function_sig(_mesa_glsl_parse_state *, ir_function *,
  44                               s_list *, bool skip_body);
  45
  46 static void read_instructions(_mesa_glsl_parse_state *, exec_list *,
  47                               s_expression *, ir_loop *);
  48 static ir_instruction *read_instruction(_mesa_glsl_parse_state *,
  49                                         s_expression *, ir_loop *);
  50 static ir_variable *read_declaration(_mesa_glsl_parse_state *, s_list *);
  51 static ir_if *read_if(_mesa_glsl_parse_state *, s_list *, ir_loop *);
  52 static ir_loop *read_loop(_mesa_glsl_parse_state *st, s_list *list);
  53 static ir_return *read_return(_mesa_glsl_parse_state *, s_list *);
  54
  55 static ir_rvalue *read_rvalue(_mesa_glsl_parse_state *, s_expression *);
  56 static ir_assignment *read_assignment(_mesa_glsl_parse_state *, s_list *);
  57 static ir_expression *read_expression(_mesa_glsl_parse_state *, s_list *);
  58 static ir_call *read_call(_mesa_glsl_parse_state *, s_list *);
  59 static ir_swizzle *read_swizzle(_mesa_glsl_parse_state *, s_list *);
  60 static ir_constant *read_constant(_mesa_glsl_parse_state *, s_list *);
  61 static ir_texture *read_texture(_mesa_glsl_parse_state *, s_list *);
  62
  63 static ir_dereference *read_dereference(_mesa_glsl_parse_state *,
  64                                         s_expression *);
  65 static ir_dereference *read_var_ref(_mesa_glsl_parse_state *, s_list *);
  66 static ir_dereference *read_array_ref(_mesa_glsl_parse_state *, s_list *);
  67 static ir_dereference *read_record_ref(_mesa_glsl_parse_state *, s_list *);
  68
  69 void
  70 _mesa_glsl_read_ir(_mesa_glsl_parse_state *state, exec_list *instructions,
  71                    const char *src, bool scan_for_protos)
  72 {
  73    s_expression *expr = s_expression::read_expression(state, src);
  74    if (expr == NULL) {
  75       ir_read_error(state, NULL, "couldn't parse S-Expression.");
  76       return;
  77    }
  78
  79    if (scan_for_protos) {
  80       scan_for_prototypes(state, instructions, expr);
  81       if (state->error)
  82          return;
  83    }
  84
  85    read_instructions(state, instructions, expr, NULL);
  86    talloc_free(expr);
  87 }
  88
  89 static void
  90 ir_read_error(_mesa_glsl_parse_state *state, s_expression *expr,
  91               const char *fmt, ...)
  92 {
  93    va_list ap;
  94
  95    state->error = true;
  96
  97    if (state->current_function != NULL)
  98       state->info_log = talloc_asprintf_append(state->info_log,
  99                            "In function %s:\n",
 100                            state->current_function->function_name());
 101    state->info_log = talloc_strdup_append(state->info_log, "error: ");
 102
 103    va_start(ap, fmt);
 104    state->info_log = talloc_vasprintf_append(state->info_log, fmt, ap);
 105    va_end(ap);
 106    state->info_log = talloc_strdup_append(state->info_log, "\n");
 107
 108    if (expr != NULL) {
 109       state->info_log = talloc_strdup_append(state->info_log,
 110                                              "...in this context:\n   ");
 111       expr->print();
 112       state->info_log = talloc_strdup_append(state->info_log, "\n\n");
 113    }
 114 }
 115
 116 static const glsl_type *
 117 read_type(_mesa_glsl_parse_state *st, s_expression *expr)
 118 {
 119    s_list *list = SX_AS_LIST(expr);
 120    if (list != NULL) {
 121       s_symbol *type_sym = SX_AS_SYMBOL(list->subexpressions.get_head());
 122       if (type_sym == NULL) {
 123          ir_read_error(st, expr, "expected type (array ...) or (struct ...)");
 124          return NULL;
 125       }
 126       if (strcmp(type_sym->value(), "array") == 0) {
 127          if (list->length() != 3) {
 128             ir_read_error(st, expr, "expected type (array <type> <int>)");
 129             return NULL;
 130          }
 131
 132          // Read base type
 133          s_expression *base_expr = (s_expression*) type_sym->next;
 134          const glsl_type *base_type = read_type(st, base_expr);
 135          if (base_type == NULL) {
 136             ir_read_error(st, NULL, "when reading base type of array");
 137             return NULL;
 138          }
 139
 140          // Read array size
 141          s_int *size = SX_AS_INT(base_expr->next);
 142          if (size == NULL) {
 143             ir_read_error(st, expr, "found non-integer array size");
 144             return NULL;
 145          }
 146
 147          return glsl_type::get_array_instance(base_type, size->value());
 148       } else if (strcmp(type_sym->value(), "struct") == 0) {
 149          assert(false); // FINISHME
 150       } else {
 151          ir_read_error(st, expr, "expected (array ...) or (struct ...); "
 152                                  "found (%s ...)", type_sym->value());
 153          return NULL;
 154       }
 155    }
 156
 157    s_symbol *type_sym = SX_AS_SYMBOL(expr);
 158    if (type_sym == NULL) {
 159       ir_read_error(st, expr, "expected <type> (symbol or list)");
 160       return NULL;
 161    }
 162
 163    const glsl_type *type = st->symbols->get_type(type_sym->value());
 164    if (type == NULL)
 165       ir_read_error(st, expr, "invalid type: %s", type_sym->value());
 166
 167    return type;
 168 }
 169
 170
 171 static void
 172 scan_for_prototypes(_mesa_glsl_parse_state *st, exec_list *instructions,
 173                     s_expression *expr)
 174 {
 175    s_list *list = SX_AS_LIST(expr);
 176    if (list == NULL) {
 177       ir_read_error(st, expr, "Expected (<instruction> ...); found an atom.");
 178       return;
 179    }
 180
 181    foreach_iter(exec_list_iterator, it, list->subexpressions) {
 182       s_list *sub = SX_AS_LIST(it.get());
 183       if (sub == NULL)
 184          continue; // not a (function ...); ignore it.
 185
 186       s_symbol *tag = SX_AS_SYMBOL(sub->subexpressions.get_head());
 187       if (tag == NULL || strcmp(tag->value(), "function") != 0)
 188          continue; // not a (function ...); ignore it.
 189
 190       ir_function *f = read_function(st, sub, true);
 191       if (f == NULL)
 192          return;
 193       instructions->push_tail(f);
 194    }
 195 }
 196
 197 static ir_function *
 198 read_function(_mesa_glsl_parse_state *st, s_list *list, bool skip_body)
 199 {
 200    void *ctx = st;
 201    bool added = false;
 202    if (list->length() < 3) {
 203       ir_read_error(st, list, "Expected (function <name> (signature ...) ...)");
 204       return NULL;
 205    }
 206
 207    s_symbol *name = SX_AS_SYMBOL(list->subexpressions.head->next);
 208    if (name == NULL) {
 209       ir_read_error(st, list, "Expected (function <name> ...)");
 210       return NULL;
 211    }
 212
 213    ir_function *f = st->symbols->get_function(name->value());
 214    if (f == NULL) {
 215       f = new(ctx) ir_function(name->value());
 216       f->is_builtin = true;
 217       added = st->symbols->add_function(f->name, f);
 218       assert(added);
 219    }
 220
 221    exec_list_iterator it = list->subexpressions.iterator();
 222    it.next(); // skip "function" tag
 223    it.next(); // skip function name
 224    for (/* nothing */; it.has_next(); it.next()) {
 225       s_list *siglist = SX_AS_LIST(it.get());
 226       if (siglist == NULL) {
 227          ir_read_error(st, list, "Expected (function (signature ...) ...)");
 228          return NULL;
 229       }
 230
 231       s_symbol *tag = SX_AS_SYMBOL(siglist->subexpressions.get_head());
 232       if (tag == NULL || strcmp(tag->value(), "signature") != 0) {
 233          ir_read_error(st, siglist, "Expected (signature ...)");
 234          return NULL;
 235       }
 236
 237       read_function_sig(st, f, siglist, skip_body);
 238    }
 239    return added ? f : NULL;
 240 }
 241
 242 static void
 243 read_function_sig(_mesa_glsl_parse_state *st, ir_function *f, s_list *list,
 244                   bool skip_body)
 245 {
 246    void *ctx = st;
 247    if (list->length() != 4) {
 248       ir_read_error(st, list, "Expected (signature <type> (parameters ...) "
 249                               "(<instruction> ...))");
 250       return;
 251    }
 252
 253    s_expression *type_expr = (s_expression*) list->subexpressions.head->next;
 254    const glsl_type *return_type = read_type(st, type_expr);
 255    if (return_type == NULL)
 256       return;
 257
 258    s_list *paramlist = SX_AS_LIST(type_expr->next);
 259    s_list *body_list = SX_AS_LIST(paramlist->next);
 260    if (paramlist == NULL || body_list == NULL) {
 261       ir_read_error(st, list, "Expected (signature <type> (parameters ...) "
 262                               "(<instruction> ...))");
 263       return;
 264    }
 265    s_symbol *paramtag = SX_AS_SYMBOL(paramlist->subexpressions.get_head());
 266    if (paramtag == NULL || strcmp(paramtag->value(), "parameters") != 0) {
 267       ir_read_error(st, paramlist, "Expected (parameters ...)");
 268       return;
 269    }
 270
 271    // Read the parameters list into a temporary place.
 272    exec_list hir_parameters;
 273    st->symbols->push_scope();
 274
 275    exec_list_iterator it = paramlist->subexpressions.iterator();
 276    for (it.next() /* skip "parameters" */; it.has_next(); it.next()) {
 277       s_list *decl = SX_AS_LIST(it.get());
 278       ir_variable *var = read_declaration(st, decl);
 279       if (var == NULL)
 280          return;
 281
 282       hir_parameters.push_tail(var);
 283    }
 284
 285    ir_function_signature *sig = f->exact_matching_signature(&hir_parameters);
 286    if (sig == NULL && skip_body) {
 287       /* If scanning for prototypes, generate a new signature. */
 288       sig = new(ctx) ir_function_signature(return_type);
 289       f->add_signature(sig);
 290    } else if (sig != NULL) {
 291       const char *badvar = sig->qualifiers_match(&hir_parameters);
 292       if (badvar != NULL) {
 293          ir_read_error(st, list, "function `%s' parameter `%s' qualifiers "
 294                        "don't match prototype", f->name, badvar);
 295          return;
 296       }
 297
 298       if (sig->return_type != return_type) {
 299          ir_read_error(st, list, "function `%s' return type doesn't "
 300                        "match prototype", f->name);
 301          return;
 302       }
 303    } else {
 304       /* No prototype for this body exists - skip it. */
 305       st->symbols->pop_scope();
 306       return;
 307    }
 308    assert(sig != NULL);
 309
 310    sig->replace_parameters(&hir_parameters);
 311
 312    if (!skip_body && !body_list->subexpressions.is_empty()) {
 313       if (sig->is_defined) {
 314          ir_read_error(st, list, "function %s redefined", f->name);
 315          return;
 316       }
 317       st->current_function = sig;
 318       read_instructions(st, &sig->body, body_list, NULL);
 319       st->current_function = NULL;
 320       sig->is_defined = true;
 321    }
 322
 323    st->symbols->pop_scope();
 324 }
 325
 326 static void
 327 read_instructions(_mesa_glsl_parse_state *st, exec_list *instructions,
 328                   s_expression *expr, ir_loop *loop_ctx)
 329 {
 330    // Read in a list of instructions
 331    s_list *list = SX_AS_LIST(expr);
 332    if (list == NULL) {
 333       ir_read_error(st, expr, "Expected (<instruction> ...); found an atom.");
 334       return;
 335    }
 336
 337    foreach_iter(exec_list_iterator, it, list->subexpressions) {
 338       s_expression *sub = (s_expression*) it.get();
 339       ir_instruction *ir = read_instruction(st, sub, loop_ctx);
 340       if (ir != NULL)
 341          instructions->push_tail(ir);
 342    }
 343 }
 344
 345
 346 static ir_instruction *
 347 read_instruction(_mesa_glsl_parse_state *st, s_expression *expr,
 348                  ir_loop *loop_ctx)
 349 {
 350    void *ctx = st;
 351    s_symbol *symbol = SX_AS_SYMBOL(expr);
 352    if (symbol != NULL) {
 353       if (strcmp(symbol->value(), "break") == 0 && loop_ctx != NULL)
 354          return new(ctx) ir_loop_jump(ir_loop_jump::jump_break);
 355       if (strcmp(symbol->value(), "continue") == 0 && loop_ctx != NULL)
 356          return new(ctx) ir_loop_jump(ir_loop_jump::jump_continue);
 357    }
 358
 359    s_list *list = SX_AS_LIST(expr);
 360    if (list == NULL || list->subexpressions.is_empty()) {
 361       ir_read_error(st, expr, "Invalid instruction.\n");
 362       return NULL;
 363    }
 364
 365    s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());
 366    if (tag == NULL) {
 367       ir_read_error(st, expr, "expected instruction tag");
 368       return NULL;
 369    }
 370
 371    ir_instruction *inst = NULL;
 372    if (strcmp(tag->value(), "declare") == 0) {
 373       inst = read_declaration(st, list);
 374    } else if (strcmp(tag->value(), "assign") == 0) {
 375       inst = read_assignment(st, list);
 376    } else if (strcmp(tag->value(), "if") == 0) {
 377       inst = read_if(st, list, loop_ctx);
 378    } else if (strcmp(tag->value(), "loop") == 0) {
 379       inst = read_loop(st, list);
 380    } else if (strcmp(tag->value(), "return") == 0) {
 381       inst = read_return(st, list);
 382    } else if (strcmp(tag->value(), "function") == 0) {
 383       inst = read_function(st, list, false);
 384    } else {
 385       inst = read_rvalue(st, list);
 386       if (inst == NULL)
 387          ir_read_error(st, NULL, "when reading instruction");
 388    }
 389    return inst;
 390 }
 391
 392
 393 static ir_variable *
 394 read_declaration(_mesa_glsl_parse_state *st, s_list *list)
 395 {
 396    void *ctx = st;
 397    if (list->length() != 4) {
 398       ir_read_error(st, list, "expected (declare (<qualifiers>) <type> "
 399                               "<name>)");
 400       return NULL;
 401    }
 402
 403    s_list *quals = SX_AS_LIST(list->subexpressions.head->next);
 404    if (quals == NULL) {
 405       ir_read_error(st, list, "expected a list of variable qualifiers");
 406       return NULL;
 407    }
 408
 409    s_expression *type_expr = (s_expression*) quals->next;
 410    const glsl_type *type = read_type(st, type_expr);
 411    if (type == NULL)
 412       return NULL;
 413
 414    s_symbol *var_name = SX_AS_SYMBOL(type_expr->next);
 415    if (var_name == NULL) {
 416       ir_read_error(st, list, "expected variable name, found non-symbol");
 417       return NULL;
 418    }
 419
 420    ir_variable *var = new(ctx) ir_variable(type, var_name->value(),
 421                                            ir_var_auto);
 422
 423    foreach_iter(exec_list_iterator, it, quals->subexpressions) {
 424       s_symbol *qualifier = SX_AS_SYMBOL(it.get());
 425       if (qualifier == NULL) {
 426          ir_read_error(st, list, "qualifier list must contain only symbols");
 427          delete var;
 428          return NULL;
 429       }
 430
 431       // FINISHME: Check for duplicate/conflicting qualifiers.
 432       if (strcmp(qualifier->value(), "centroid") == 0) {
 433          var->centroid = 1;
 434       } else if (strcmp(qualifier->value(), "invariant") == 0) {
 435          var->invariant = 1;
 436       } else if (strcmp(qualifier->value(), "uniform") == 0) {
 437          var->mode = ir_var_uniform;
 438       } else if (strcmp(qualifier->value(), "auto") == 0) {
 439          var->mode = ir_var_auto;
 440       } else if (strcmp(qualifier->value(), "in") == 0) {
 441          var->mode = ir_var_in;
 442       } else if (strcmp(qualifier->value(), "out") == 0) {
 443          var->mode = ir_var_out;
 444       } else if (strcmp(qualifier->value(), "inout") == 0) {
 445          var->mode = ir_var_inout;
 446       } else if (strcmp(qualifier->value(), "smooth") == 0) {
 447          var->interpolation = ir_var_smooth;
 448       } else if (strcmp(qualifier->value(), "flat") == 0) {
 449          var->interpolation = ir_var_flat;
 450       } else if (strcmp(qualifier->value(), "noperspective") == 0) {
 451          var->interpolation = ir_var_noperspective;
 452       } else {
 453          ir_read_error(st, list, "unknown qualifier: %s", qualifier->value());
 454          delete var;
 455          return NULL;
 456       }
 457    }
 458
 459    // Add the variable to the symbol table
 460    st->symbols->add_variable(var->name, var);
 461
 462    return var;
 463 }
 464
 465
 466 static ir_if *
 467 read_if(_mesa_glsl_parse_state *st, s_list *list, ir_loop *loop_ctx)
 468 {
 469    void *ctx = st;
 470    if (list->length() != 4) {
 471       ir_read_error(st, list, "expected (if <condition> (<then> ...) "
 472                           "(<else> ...))");
 473       return NULL;
 474    }
 475
 476    s_expression *cond_expr = (s_expression*) list->subexpressions.head->next;
 477    ir_rvalue *condition = read_rvalue(st, cond_expr);
 478    if (condition == NULL) {
 479       ir_read_error(st, NULL, "when reading condition of (if ...)");
 480       return NULL;
 481    }
 482
 483    s_expression *then_expr = (s_expression*) cond_expr->next;
 484    s_expression *else_expr = (s_expression*) then_expr->next;
 485
 486    ir_if *iff = new(ctx) ir_if(condition);
 487
 488    read_instructions(st, &iff->then_instructions, then_expr, loop_ctx);
 489    read_instructions(st, &iff->else_instructions, else_expr, loop_ctx);
 490    if (st->error) {
 491       delete iff;
 492       iff = NULL;
 493    }
 494    return iff;
 495 }
 496
 497
 498 static ir_loop *
 499 read_loop(_mesa_glsl_parse_state *st, s_list *list)
 500 {
 501    void *ctx = st;
 502    if (list->length() != 6) {
 503       ir_read_error(st, list, "expected (loop <counter> <from> <to> "
 504                               "<increment> <body>)");
 505       return NULL;
 506    }
 507
 508    s_expression *count_expr = (s_expression*) list->subexpressions.head->next;
 509    s_expression *from_expr  = (s_expression*) count_expr->next;
 510    s_expression *to_expr    = (s_expression*) from_expr->next;
 511    s_expression *inc_expr   = (s_expression*) to_expr->next;
 512    s_expression *body_expr  = (s_expression*) inc_expr->next;
 513
 514    // FINISHME: actually read the count/from/to fields.
 515
 516    ir_loop *loop = new(ctx) ir_loop;
 517    read_instructions(st, &loop->body_instructions, body_expr, loop);
 518    if (st->error) {
 519       delete loop;
 520       loop = NULL;
 521    }
 522    return loop;
 523 }
 524
 525
 526 static ir_return *
 527 read_return(_mesa_glsl_parse_state *st, s_list *list)
 528 {
 529    void *ctx = st;
 530    if (list->length() != 2) {
 531       ir_read_error(st, list, "expected (return <rvalue>)");
 532       return NULL;
 533    }
 534
 535    s_expression *expr = (s_expression*) list->subexpressions.head->next;
 536
 537    ir_rvalue *retval = read_rvalue(st, expr);
 538    if (retval == NULL) {
 539       ir_read_error(st, NULL, "when reading return value");
 540       return NULL;
 541    }
 542
 543    return new(ctx) ir_return(retval);
 544 }
 545
 546
 547 static ir_rvalue *
 548 read_rvalue(_mesa_glsl_parse_state *st, s_expression *expr)
 549 {
 550    s_list *list = SX_AS_LIST(expr);
 551    if (list == NULL || list->subexpressions.is_empty())
 552       return NULL;
 553
 554    s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());
 555    if (tag == NULL) {
 556       ir_read_error(st, expr, "expected rvalue tag");
 557       return NULL;
 558    }
 559
 560    ir_rvalue *rvalue = read_dereference(st, list);
 561    if (rvalue != NULL || st->error)
 562       return rvalue;
 563    else if (strcmp(tag->value(), "swiz") == 0) {
 564       rvalue = read_swizzle(st, list);
 565    } else if (strcmp(tag->value(), "expression") == 0) {
 566       rvalue = read_expression(st, list);
 567    } else if (strcmp(tag->value(), "call") == 0) {
 568       rvalue = read_call(st, list);
 569    } else if (strcmp(tag->value(), "constant") == 0) {
 570       rvalue = read_constant(st, list);
 571    } else {
 572       rvalue = read_texture(st, list);
 573       if (rvalue == NULL && !st->error)
 574          ir_read_error(st, expr, "unrecognized rvalue tag: %s", tag->value());
 575    }
 576
 577    return rvalue;
 578 }
 579
 580 static ir_assignment *
 581 read_assignment(_mesa_glsl_parse_state *st, s_list *list)
 582 {
 583    void *ctx = st;
 584    const unsigned list_length = list->length();
 585    if (list_length < 4 || list_length > 5) {
 586       ir_read_error(st, list, "expected (assign <condition> (<write mask>) "
 587                               "<lhs> <rhs>)");
 588       return NULL;
 589    }
 590
 591    s_expression *cond_expr = (s_expression*) list->subexpressions.head->next;
 592    s_list       *mask_list = SX_AS_LIST(cond_expr->next);
 593    s_expression *lhs_expr  = (s_expression*)
 594       (list_length == 4 ? cond_expr->next : cond_expr->next->next);
 595    s_expression *rhs_expr  = (s_expression*) lhs_expr->next;
 596
 597    ir_rvalue *condition = read_rvalue(st, cond_expr);
 598    if (condition == NULL) {
 599       ir_read_error(st, NULL, "when reading condition of assignment");
 600       return NULL;
 601    }
 602
 603    if (list_length == 5 && mask_list == NULL || mask_list->length() > 1) {
 604       ir_read_error(st, mask_list, "expected () or (<write mask>)");
 605       return NULL;
 606    }
 607
 608    unsigned mask = 0;
 609    if (list_length == 5 && mask_list->length() == 1) {
 610       s_symbol *mask_symbol = SX_AS_SYMBOL(mask_list->subexpressions.head);
 611       if (mask_symbol == NULL) {
 612          ir_read_error(st, list, "expected a write mask; found non-symbol");
 613          return NULL;
 614       }
 615
 616       const char *mask_str = mask_symbol->value();
 617       unsigned mask_length = strlen(mask_str);
 618       if (mask_length > 4) {
 619          ir_read_error(st, list, "invalid write mask: %s", mask_str);
 620          return NULL;
 621       }
 622
 623       const unsigned idx_map[] = { 3, 0, 1, 2 }; /* w=bit 3, x=0, y=1, z=2 */
 624
 625       for (unsigned i = 0; i < mask_length; i++) {
 626          if (mask_str[i] < 'w' || mask_str[i] > 'z') {
 627             ir_read_error(st, list, "write mask contains invalid character: %c",
 628                           mask_str[i]);
 629             return NULL;
 630          }
 631          mask |= 1 << idx_map[mask_str[i] - 'w'];
 632       }
 633    }
 634
 635    ir_dereference *lhs = read_dereference(st, lhs_expr);
 636    if (lhs == NULL) {
 637       ir_read_error(st, NULL, "when reading left-hand side of assignment");
 638       return NULL;
 639    }
 640
 641    ir_rvalue *rhs = read_rvalue(st, rhs_expr);
 642    if (rhs == NULL) {
 643       ir_read_error(st, NULL, "when reading right-hand side of assignment");
 644       return NULL;
 645    }
 646
 647    if (mask == 0 && (lhs->type->is_vector() || lhs->type->is_scalar())) {
 648       ir_read_error(st, list, "non-zero write mask required.");
 649       return NULL;
 650    }
 651
 652    return new(ctx) ir_assignment(lhs, rhs, condition, mask);
 653 }
 654
 655 static ir_call *
 656 read_call(_mesa_glsl_parse_state *st, s_list *list)
 657 {
 658    void *ctx = st;
 659    if (list->length() != 3) {
 660       ir_read_error(st, list, "expected (call <name> (<param> ...))");
 661       return NULL;
 662    }
 663
 664    s_symbol *name = SX_AS_SYMBOL(list->subexpressions.head->next);
 665    s_list *params = SX_AS_LIST(name->next);
 666    if (name == NULL || params == NULL) {
 667       ir_read_error(st, list, "expected (call <name> (<param> ...))");
 668       return NULL;
 669    }
 670
 671    exec_list parameters;
 672
 673    foreach_iter(exec_list_iterator, it, params->subexpressions) {
 674       s_expression *expr = (s_expression*) it.get();
 675       ir_rvalue *param = read_rvalue(st, expr);
 676       if (param == NULL) {
 677          ir_read_error(st, list, "when reading parameter to function call");
 678          return NULL;
 679       }
 680       parameters.push_tail(param);
 681    }
 682
 683    ir_function *f = st->symbols->get_function(name->value());
 684    if (f == NULL) {
 685       ir_read_error(st, list, "found call to undefined function %s",
 686                     name->value());
 687       return NULL;
 688    }
 689
 690    ir_function_signature *callee = f->matching_signature(&parameters);
 691    if (callee == NULL) {
 692       ir_read_error(st, list, "couldn't find matching signature for function "
 693                     "%s", name->value());
 694       return NULL;
 695    }
 696
 697    return new(ctx) ir_call(callee, &parameters);
 698 }
 699
 700 static ir_expression *
 701 read_expression(_mesa_glsl_parse_state *st, s_list *list)
 702 {
 703    void *ctx = st;
 704    const unsigned list_length = list->length();
 705    if (list_length < 4) {
 706       ir_read_error(st, list, "expected (expression <type> <operator> "
 707                               "<operand> [<operand>])");
 708       return NULL;
 709    }
 710
 711    s_expression *type_expr = (s_expression*) list->subexpressions.head->next;
 712    const glsl_type *type = read_type(st, type_expr);
 713    if (type == NULL)
 714       return NULL;
 715
 716    /* Read the operator */
 717    s_symbol *op_sym = SX_AS_SYMBOL(type_expr->next);
 718    if (op_sym == NULL) {
 719       ir_read_error(st, list, "expected operator, found non-symbol");
 720       return NULL;
 721    }
 722
 723    ir_expression_operation op = ir_expression::get_operator(op_sym->value());
 724    if (op == (ir_expression_operation) -1) {
 725       ir_read_error(st, list, "invalid operator: %s", op_sym->value());
 726       return NULL;
 727    }
 728
 729    /* Now that we know the operator, check for the right number of operands */
 730    if (ir_expression::get_num_operands(op) == 2) {
 731       if (list_length != 5) {
 732          ir_read_error(st, list, "expected (expression <type> %s <operand> "
 733                                  " <operand>)", op_sym->value());
 734          return NULL;
 735       }
 736    } else {
 737       if (list_length != 4) {
 738          ir_read_error(st, list, "expected (expression <type> %s <operand>)",
 739                        op_sym->value());
 740          return NULL;
 741       }
 742    }
 743
 744    s_expression *exp1 = (s_expression*) (op_sym->next);
 745    ir_rvalue *arg1 = read_rvalue(st, exp1);
 746    if (arg1 == NULL) {
 747       ir_read_error(st, NULL, "when reading first operand of %s",
 748                     op_sym->value());
 749       return NULL;
 750    }
 751
 752    ir_rvalue *arg2 = NULL;
 753    if (ir_expression::get_num_operands(op) == 2) {
 754       s_expression *exp2 = (s_expression*) (exp1->next);
 755       arg2 = read_rvalue(st, exp2);
 756       if (arg2 == NULL) {
 757          ir_read_error(st, NULL, "when reading second operand of %s",
 758                        op_sym->value());
 759          return NULL;
 760       }
 761    }
 762
 763    return new(ctx) ir_expression(op, type, arg1, arg2);
 764 }
 765
 766 static ir_swizzle *
 767 read_swizzle(_mesa_glsl_parse_state *st, s_list *list)
 768 {
 769    if (list->length() != 3) {
 770       ir_read_error(st, list, "expected (swiz <swizzle> <rvalue>)");
 771       return NULL;
 772    }
 773
 774    s_symbol *swiz = SX_AS_SYMBOL(list->subexpressions.head->next);
 775    if (swiz == NULL) {
 776       ir_read_error(st, list, "expected a valid swizzle; found non-symbol");
 777       return NULL;
 778    }
 779
 780    if (strlen(swiz->value()) > 4) {
 781       ir_read_error(st, list, "expected a valid swizzle; found %s",
 782                     swiz->value());
 783       return NULL;
 784    }
 785
 786    s_expression *sub = (s_expression*) swiz->next;
 787    if (sub == NULL) {
 788       ir_read_error(st, list, "expected rvalue: (swizzle %s <rvalue>)",
 789                     swiz->value());
 790       return NULL;
 791    }
 792
 793    ir_rvalue *rvalue = read_rvalue(st, sub);
 794    if (rvalue == NULL)
 795       return NULL;
 796
 797    ir_swizzle *ir = ir_swizzle::create(rvalue, swiz->value(),
 798                                        rvalue->type->vector_elements);
 799    if (ir == NULL)
 800       ir_read_error(st, list, "invalid swizzle");
 801
 802    return ir;
 803 }
 804
 805 static ir_constant *
 806 read_constant(_mesa_glsl_parse_state *st, s_list *list)
 807 {
 808    void *ctx = st;
 809    if (list->length() != 3) {
 810       ir_read_error(st, list, "expected (constant <type> (...))");
 811       return NULL;
 812    }
 813
 814    s_expression *type_expr = (s_expression*) list->subexpressions.head->next;
 815    const glsl_type *type = read_type(st, type_expr);
 816    if (type == NULL)
 817       return NULL;
 818
 819    s_list *values = SX_AS_LIST(type_expr->next);
 820    if (values == NULL) {
 821       ir_read_error(st, list, "expected (constant <type> (...))");
 822       return NULL;
 823    }
 824
 825    if (type->is_array()) {
 826       const unsigned elements_supplied = values->length();
 827       if (elements_supplied != type->length) {
 828          ir_read_error(st, values, "expected exactly %u array elements, "
 829                        "given %u", type->length, elements_supplied);
 830          return NULL;
 831       }
 832
 833       exec_list elements;
 834       foreach_iter(exec_list_iterator, it, values->subexpressions) {
 835          s_expression *expr = (s_expression *) it.get();
 836          s_list *elt = SX_AS_LIST(expr);
 837          if (elt == NULL) {
 838             ir_read_error(st, expr, "expected (constant ...) array element");
 839             return NULL;
 840          }
 841
 842          ir_constant *ir_elt = read_constant(st, elt);
 843          if (ir_elt == NULL)
 844             return NULL;
 845          elements.push_tail(ir_elt);
 846       }
 847       return new(ctx) ir_constant(type, &elements);
 848    }
 849
 850    const glsl_type *const base_type = type->get_base_type();
 851
 852    ir_constant_data data = { { 0 } };
 853
 854    // Read in list of values (at most 16).
 855    int k = 0;
 856    foreach_iter(exec_list_iterator, it, values->subexpressions) {
 857       if (k >= 16) {
 858          ir_read_error(st, values, "expected at most 16 numbers");
 859          return NULL;
 860       }
 861
 862       s_expression *expr = (s_expression*) it.get();
 863
 864       if (base_type->base_type == GLSL_TYPE_FLOAT) {
 865          s_number *value = SX_AS_NUMBER(expr);
 866          if (value == NULL) {
 867             ir_read_error(st, values, "expected numbers");
 868             return NULL;
 869          }
 870          data.f[k] = value->fvalue();
 871       } else {
 872          s_int *value = SX_AS_INT(expr);
 873          if (value == NULL) {
 874             ir_read_error(st, values, "expected integers");
 875             return NULL;
 876          }
 877
 878          switch (base_type->base_type) {
 879          case GLSL_TYPE_UINT: {
 880             data.u[k] = value->value();
 881             break;
 882          }
 883          case GLSL_TYPE_INT: {
 884             data.i[k] = value->value();
 885             break;
 886          }
 887          case GLSL_TYPE_BOOL: {
 888             data.b[k] = value->value();
 889             break;
 890          }
 891          default:
 892             ir_read_error(st, values, "unsupported constant type");
 893             return NULL;
 894          }
 895       }
 896       ++k;
 897    }
 898
 899    return new(ctx) ir_constant(type, &data);
 900 }
 901
 902 static ir_dereference *
 903 read_dereference(_mesa_glsl_parse_state *st, s_expression *expr)
 904 {
 905    s_list *list = SX_AS_LIST(expr);
 906    if (list == NULL || list->subexpressions.is_empty())
 907       return NULL;
 908
 909    s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.head);
 910    assert(tag != NULL);
 911
 912    if (strcmp(tag->value(), "var_ref") == 0)
 913       return read_var_ref(st, list);
 914    if (strcmp(tag->value(), "array_ref") == 0)
 915       return read_array_ref(st, list);
 916    if (strcmp(tag->value(), "record_ref") == 0)
 917       return read_record_ref(st, list);
 918    return NULL;
 919 }
 920
 921 static ir_dereference *
 922 read_var_ref(_mesa_glsl_parse_state *st, s_list *list)
 923 {
 924    void *ctx = st;
 925    if (list->length() != 2) {
 926       ir_read_error(st, list, "expected (var_ref <variable name>)");
 927       return NULL;
 928    }
 929    s_symbol *var_name = SX_AS_SYMBOL(list->subexpressions.head->next);
 930    if (var_name == NULL) {
 931       ir_read_error(st, list, "expected (var_ref <variable name>)");
 932       return NULL;
 933    }
 934
 935    ir_variable *var = st->symbols->get_variable(var_name->value());
 936    if (var == NULL) {
 937       ir_read_error(st, list, "undeclared variable: %s", var_name->value());
 938       return NULL;
 939    }
 940
 941    return new(ctx) ir_dereference_variable(var);
 942 }
 943
 944 static ir_dereference *
 945 read_array_ref(_mesa_glsl_parse_state *st, s_list *list)
 946 {
 947    void *ctx = st;
 948    if (list->length() != 3) {
 949       ir_read_error(st, list, "expected (array_ref <rvalue> <index>)");
 950       return NULL;
 951    }
 952
 953    s_expression *subj_expr = (s_expression*) list->subexpressions.head->next;
 954    ir_rvalue *subject = read_rvalue(st, subj_expr);
 955    if (subject == NULL) {
 956       ir_read_error(st, NULL, "when reading the subject of an array_ref");
 957       return NULL;
 958    }
 959
 960    s_expression *idx_expr = (s_expression*) subj_expr->next;
 961    ir_rvalue *idx = read_rvalue(st, idx_expr);
 962    return new(ctx) ir_dereference_array(subject, idx);
 963 }
 964
 965 static ir_dereference *
 966 read_record_ref(_mesa_glsl_parse_state *st, s_list *list)
 967 {
 968    void *ctx = st;
 969    if (list->length() != 3) {
 970       ir_read_error(st, list, "expected (record_ref <rvalue> <field>)");
 971       return NULL;
 972    }
 973
 974    s_expression *subj_expr = (s_expression*) list->subexpressions.head->next;
 975    ir_rvalue *subject = read_rvalue(st, subj_expr);
 976    if (subject == NULL) {
 977       ir_read_error(st, NULL, "when reading the subject of a record_ref");
 978       return NULL;
 979    }
 980
 981    s_symbol *field = SX_AS_SYMBOL(subj_expr->next);
 982    if (field == NULL) {
 983       ir_read_error(st, list, "expected (record_ref ... <field name>)");
 984       return NULL;
 985    }
 986    return new(ctx) ir_dereference_record(subject, field->value());
 987 }
 988
 989 static bool
 990 valid_texture_list_length(ir_texture_opcode op, s_list *list)
 991 {
 992    unsigned required_length = 7;
 993    if (op == ir_txf)
 994       required_length = 5;
 995    else if (op == ir_tex)
 996       required_length = 6;
 997
 998    return list->length() == required_length;
 999 }
1000
1001 static ir_texture *
1002 read_texture(_mesa_glsl_parse_state *st, s_list *list)
1003 {
1004    void *ctx = st;
1005    s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.head);
1006    assert(tag != NULL);
1007
1008    ir_texture_opcode op = ir_texture::get_opcode(tag->value());
1009    if (op == (ir_texture_opcode) -1)
1010       return NULL;
1011
1012    if (!valid_texture_list_length(op, list)) {
1013       ir_read_error(st, NULL, "invalid list size in (%s ...)", tag->value());
1014       return NULL;
1015    }
1016
1017    ir_texture *tex = new(ctx) ir_texture(op);
1018
1019    // Read sampler (must be a deref)
1020    s_expression *sampler_expr = (s_expression *) tag->next;
1021    ir_dereference *sampler = read_dereference(st, sampler_expr);
1022    if (sampler == NULL) {
1023       ir_read_error(st, NULL, "when reading sampler in (%s ...)", tag->value());
1024       return NULL;
1025    }
1026    tex->set_sampler(sampler);
1027
1028    // Read coordinate (any rvalue)
1029    s_expression *coordinate_expr = (s_expression *) sampler_expr->next;
1030    tex->coordinate = read_rvalue(st, coordinate_expr);
1031    if (tex->coordinate == NULL) {
1032       ir_read_error(st, NULL, "when reading coordinate in (%s ...)",
1033                     tag->value());
1034       return NULL;
1035    }
1036
1037    // Read texel offset, i.e. (0 0 0)
1038    s_list *offset_list = SX_AS_LIST(coordinate_expr->next);
1039    if (offset_list == NULL || offset_list->length() != 3) {
1040       ir_read_error(st, offset_list, "expected (<int> <int> <int>)");
1041       return NULL;
1042    }
1043    s_int *offset_x = SX_AS_INT(offset_list->subexpressions.head);
1044    s_int *offset_y = SX_AS_INT(offset_x->next);
1045    s_int *offset_z = SX_AS_INT(offset_y->next);
1046    if (offset_x == NULL || offset_y == NULL || offset_z == NULL) {
1047       ir_read_error(st, offset_list, "expected (<int> <int> <int>)");
1048       return NULL;
1049    }
1050    tex->offsets[0] = offset_x->value();
1051    tex->offsets[1] = offset_y->value();
1052    tex->offsets[2] = offset_z->value();
1053
1054    if (op == ir_txf) {
1055       s_expression *lod_expr = (s_expression *) offset_list->next;
1056       tex->lod_info.lod = read_rvalue(st, lod_expr);
1057       if (tex->lod_info.lod == NULL) {
1058          ir_read_error(st, NULL, "when reading LOD in (txf ...)");
1059          return NULL;
1060       }
1061    } else {
1062       s_expression *proj_expr = (s_expression *) offset_list->next;
1063       s_int *proj_as_int = SX_AS_INT(proj_expr);
1064       if (proj_as_int && proj_as_int->value() == 1) {
1065          tex->projector = NULL;
1066       } else {
1067          tex->projector = read_rvalue(st, proj_expr);
1068          if (tex->projector == NULL) {
1069             ir_read_error(st, NULL, "when reading projective divide in (%s ..)",
1070                           tag->value());
1071             return NULL;
1072          }
1073       }
1074
1075       s_list *shadow_list = SX_AS_LIST(proj_expr->next);
1076       if (shadow_list == NULL) {
1077          ir_read_error(st, NULL, "shadow comparitor must be a list");
1078          return NULL;
1079       }
1080       if (shadow_list->subexpressions.is_empty()) {
1081          tex->shadow_comparitor= NULL;
1082       } else {
1083          tex->shadow_comparitor = read_rvalue(st, shadow_list);
1084          if (tex->shadow_comparitor == NULL) {
1085             ir_read_error(st, NULL, "when reading shadow comparitor in (%s ..)",
1086                           tag->value());
1087             return NULL;
1088          }
1089       }
1090       s_expression *lod_expr = (s_expression *) shadow_list->next;
1091
1092       switch (op) {
1093       case ir_txb:
1094          tex->lod_info.bias = read_rvalue(st, lod_expr);
1095          if (tex->lod_info.bias == NULL) {
1096             ir_read_error(st, NULL, "when reading LOD bias in (txb ...)");
1097             return NULL;
1098          }
1099          break;
1100       case ir_txl:
1101          tex->lod_info.lod = read_rvalue(st, lod_expr);
1102          if (tex->lod_info.lod == NULL) {
1103             ir_read_error(st, NULL, "when reading LOD in (txl ...)");
1104             return NULL;
1105          }
1106          break;
1107       case ir_txd: {
1108          s_list *lod_list = SX_AS_LIST(lod_expr);
1109          if (lod_list->length() != 2) {
1110             ir_read_error(st, lod_expr, "expected (dPdx dPdy) in (txd ...)");
1111             return NULL;
1112          }
1113          s_expression *dx_expr = (s_expression *) lod_list->subexpressions.head;
1114          s_expression *dy_expr = (s_expression *) dx_expr->next;
1115
1116          tex->lod_info.grad.dPdx = read_rvalue(st, dx_expr);
1117          if (tex->lod_info.grad.dPdx == NULL) {
1118             ir_read_error(st, NULL, "when reading dPdx in (txd ...)");
1119             return NULL;
1120          }
1121          tex->lod_info.grad.dPdy = read_rvalue(st, dy_expr);
1122          if (tex->lod_info.grad.dPdy == NULL) {
1123             ir_read_error(st, NULL, "when reading dPdy in (txd ...)");
1124             return NULL;
1125          }
1126          break;
1127       }
1128       default:
1129          // tex doesn't have any extra parameters and txf was handled earlier.
1130          break;
1131       };
1132    }
1133    return tex;
1134 }