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 "ir_reader.h"
  25 #include "glsl_parser_extras.h"
  26 #include "glsl_types.h"
  27 #include "s_expression.h"
  28
  29 const static bool debug = false;
  30
  31 class ir_reader {
  32 public:
  33    ir_reader(_mesa_glsl_parse_state *);
  34
  35    void read(exec_list *instructions, const char *src, bool scan_for_protos);
  36
  37 private:
  38    void *mem_ctx;
  39    _mesa_glsl_parse_state *state;
  40
  41    void ir_read_error(s_expression *, const char *fmt, ...);
  42
  43    const glsl_type *read_type(s_expression *);
  44
  45    void scan_for_prototypes(exec_list *, s_expression *);
  46    ir_function *read_function(s_expression *, bool skip_body);
  47    void read_function_sig(ir_function *, s_expression *, bool skip_body);
  48
  49    void read_instructions(exec_list *, s_expression *, ir_loop *);
  50    ir_instruction *read_instruction(s_expression *, ir_loop *);
  51    ir_variable *read_declaration(s_expression *);
  52    ir_if *read_if(s_expression *, ir_loop *);
  53    ir_loop *read_loop(s_expression *);
  54    ir_return *read_return(s_expression *);
  55    ir_rvalue *read_rvalue(s_expression *);
  56    ir_assignment *read_assignment(s_expression *);
  57    ir_expression *read_expression(s_expression *);
  58    ir_call *read_call(s_expression *);
  59    ir_swizzle *read_swizzle(s_expression *);
  60    ir_constant *read_constant(s_expression *);
  61    ir_texture *read_texture(s_expression *);
  62
  63    ir_dereference *read_dereference(s_expression *);
  64 };
  65
  66 ir_reader::ir_reader(_mesa_glsl_parse_state *state) : state(state)
  67 {
  68    this->mem_ctx = state;
  69 }
  70
  71 void
  72 _mesa_glsl_read_ir(_mesa_glsl_parse_state *state, exec_list *instructions,
  73                    const char *src, bool scan_for_protos)
  74 {
  75    ir_reader r(state);
  76    r.read(instructions, src, scan_for_protos);
  77 }
  78
  79 void
  80 ir_reader::read(exec_list *instructions, const char *src, bool scan_for_protos)
  81 {
  82    s_expression *expr = s_expression::read_expression(mem_ctx, src);
  83    if (expr == NULL) {
  84       ir_read_error(NULL, "couldn't parse S-Expression.");
  85       return;
  86    }
  87
  88    if (scan_for_protos) {
  89       scan_for_prototypes(instructions, expr);
  90       if (state->error)
  91          return;
  92    }
  93
  94    read_instructions(instructions, expr, NULL);
  95    ralloc_free(expr);
  96
  97    if (debug)
  98       validate_ir_tree(instructions);
  99 }
 100
 101 void
 102 ir_reader::ir_read_error(s_expression *expr, const char *fmt, ...)
 103 {
 104    va_list ap;
 105
 106    state->error = true;
 107
 108    if (state->current_function != NULL)
 109       ralloc_asprintf_append(&state->info_log, "In function %s:\n",
 110                              state->current_function->function_name());
 111    ralloc_strcat(&state->info_log, "error: ");
 112
 113    va_start(ap, fmt);
 114    ralloc_vasprintf_append(&state->info_log, fmt, ap);
 115    va_end(ap);
 116    ralloc_strcat(&state->info_log, "\n");
 117
 118    if (expr != NULL) {
 119       ralloc_strcat(&state->info_log, "...in this context:\n   ");
 120       expr->print();
 121       ralloc_strcat(&state->info_log, "\n\n");
 122    }
 123 }
 124
 125 const glsl_type *
 126 ir_reader::read_type(s_expression *expr)
 127 {
 128    s_expression *s_base_type;
 129    s_int *s_size;
 130
 131    s_pattern pat[] = { "array", s_base_type, s_size };
 132    if (MATCH(expr, pat)) {
 133       const glsl_type *base_type = read_type(s_base_type);
 134       if (base_type == NULL) {
 135          ir_read_error(NULL, "when reading base type of array type");
 136          return NULL;
 137       }
 138
 139       return glsl_type::get_array_instance(base_type, s_size->value());
 140    }
 141
 142    s_symbol *type_sym = SX_AS_SYMBOL(expr);
 143    if (type_sym == NULL) {
 144       ir_read_error(expr, "expected <type>");
 145       return NULL;
 146    }
 147
 148    const glsl_type *type = state->symbols->get_type(type_sym->value());
 149    if (type == NULL)
 150       ir_read_error(expr, "invalid type: %s", type_sym->value());
 151
 152    return type;
 153 }
 154
 155
 156 void
 157 ir_reader::scan_for_prototypes(exec_list *instructions, s_expression *expr)
 158 {
 159    s_list *list = SX_AS_LIST(expr);
 160    if (list == NULL) {
 161       ir_read_error(expr, "Expected (<instruction> ...); found an atom.");
 162       return;
 163    }
 164
 165    foreach_iter(exec_list_iterator, it, list->subexpressions) {
 166       s_list *sub = SX_AS_LIST(it.get());
 167       if (sub == NULL)
 168          continue; // not a (function ...); ignore it.
 169
 170       s_symbol *tag = SX_AS_SYMBOL(sub->subexpressions.get_head());
 171       if (tag == NULL || strcmp(tag->value(), "function") != 0)
 172          continue; // not a (function ...); ignore it.
 173
 174       ir_function *f = read_function(sub, true);
 175       if (f == NULL)
 176          return;
 177       instructions->push_tail(f);
 178    }
 179 }
 180
 181 ir_function *
 182 ir_reader::read_function(s_expression *expr, bool skip_body)
 183 {
 184    bool added = false;
 185    s_symbol *name;
 186
 187    s_pattern pat[] = { "function", name };
 188    if (!PARTIAL_MATCH(expr, pat)) {
 189       ir_read_error(expr, "Expected (function <name> (signature ...) ...)");
 190       return NULL;
 191    }
 192
 193    ir_function *f = state->symbols->get_function(name->value());
 194    if (f == NULL) {
 195       f = new(mem_ctx) ir_function(name->value());
 196       added = state->symbols->add_function(f);
 197       assert(added);
 198    }
 199
 200    exec_list_iterator it = ((s_list *) expr)->subexpressions.iterator();
 201    it.next(); // skip "function" tag
 202    it.next(); // skip function name
 203    for (/* nothing */; it.has_next(); it.next()) {
 204       s_expression *s_sig = (s_expression *) it.get();
 205       read_function_sig(f, s_sig, skip_body);
 206    }
 207    return added ? f : NULL;
 208 }
 209
 210 void
 211 ir_reader::read_function_sig(ir_function *f, s_expression *expr, bool skip_body)
 212 {
 213    s_expression *type_expr;
 214    s_list *paramlist;
 215    s_list *body_list;
 216
 217    s_pattern pat[] = { "signature", type_expr, paramlist, body_list };
 218    if (!MATCH(expr, pat)) {
 219       ir_read_error(expr, "Expected (signature <type> (parameters ...) "
 220                           "(<instruction> ...))");
 221       return;
 222    }
 223
 224    const glsl_type *return_type = read_type(type_expr);
 225    if (return_type == NULL)
 226       return;
 227
 228    s_symbol *paramtag = SX_AS_SYMBOL(paramlist->subexpressions.get_head());
 229    if (paramtag == NULL || strcmp(paramtag->value(), "parameters") != 0) {
 230       ir_read_error(paramlist, "Expected (parameters ...)");
 231       return;
 232    }
 233
 234    // Read the parameters list into a temporary place.
 235    exec_list hir_parameters;
 236    state->symbols->push_scope();
 237
 238    exec_list_iterator it = paramlist->subexpressions.iterator();
 239    for (it.next() /* skip "parameters" */; it.has_next(); it.next()) {
 240       ir_variable *var = read_declaration((s_expression *) it.get());
 241       if (var == NULL)
 242          return;
 243
 244       hir_parameters.push_tail(var);
 245    }
 246
 247    ir_function_signature *sig = f->exact_matching_signature(&hir_parameters);
 248    if (sig == NULL && skip_body) {
 249       /* If scanning for prototypes, generate a new signature. */
 250       sig = new(mem_ctx) ir_function_signature(return_type);
 251       sig->is_builtin = true;
 252       f->add_signature(sig);
 253    } else if (sig != NULL) {
 254       const char *badvar = sig->qualifiers_match(&hir_parameters);
 255       if (badvar != NULL) {
 256          ir_read_error(expr, "function `%s' parameter `%s' qualifiers "
 257                        "don't match prototype", f->name, badvar);
 258          return;
 259       }
 260
 261       if (sig->return_type != return_type) {
 262          ir_read_error(expr, "function `%s' return type doesn't "
 263                        "match prototype", f->name);
 264          return;
 265       }
 266    } else {
 267       /* No prototype for this body exists - skip it. */
 268       state->symbols->pop_scope();
 269       return;
 270    }
 271    assert(sig != NULL);
 272
 273    sig->replace_parameters(&hir_parameters);
 274
 275    if (!skip_body && !body_list->subexpressions.is_empty()) {
 276       if (sig->is_defined) {
 277          ir_read_error(expr, "function %s redefined", f->name);
 278          return;
 279       }
 280       state->current_function = sig;
 281       read_instructions(&sig->body, body_list, NULL);
 282       state->current_function = NULL;
 283       sig->is_defined = true;
 284    }
 285
 286    state->symbols->pop_scope();
 287 }
 288
 289 void
 290 ir_reader::read_instructions(exec_list *instructions, s_expression *expr,
 291                              ir_loop *loop_ctx)
 292 {
 293    // Read in a list of instructions
 294    s_list *list = SX_AS_LIST(expr);
 295    if (list == NULL) {
 296       ir_read_error(expr, "Expected (<instruction> ...); found an atom.");
 297       return;
 298    }
 299
 300    foreach_iter(exec_list_iterator, it, list->subexpressions) {
 301       s_expression *sub = (s_expression*) it.get();
 302       ir_instruction *ir = read_instruction(sub, loop_ctx);
 303       if (ir != NULL) {
 304          /* Global variable declarations should be moved to the top, before
 305           * any functions that might use them.  Functions are added to the
 306           * instruction stream when scanning for prototypes, so without this
 307           * hack, they always appear before variable declarations.
 308           */
 309          if (state->current_function == NULL && ir->as_variable() != NULL)
 310             instructions->push_head(ir);
 311          else
 312             instructions->push_tail(ir);
 313       }
 314    }
 315 }
 316
 317
 318 ir_instruction *
 319 ir_reader::read_instruction(s_expression *expr, ir_loop *loop_ctx)
 320 {
 321    s_symbol *symbol = SX_AS_SYMBOL(expr);
 322    if (symbol != NULL) {
 323       if (strcmp(symbol->value(), "break") == 0 && loop_ctx != NULL)
 324          return new(mem_ctx) ir_loop_jump(ir_loop_jump::jump_break);
 325       if (strcmp(symbol->value(), "continue") == 0 && loop_ctx != NULL)
 326          return new(mem_ctx) ir_loop_jump(ir_loop_jump::jump_continue);
 327    }
 328
 329    s_list *list = SX_AS_LIST(expr);
 330    if (list == NULL || list->subexpressions.is_empty()) {
 331       ir_read_error(expr, "Invalid instruction.\n");
 332       return NULL;
 333    }
 334
 335    s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());
 336    if (tag == NULL) {
 337       ir_read_error(expr, "expected instruction tag");
 338       return NULL;
 339    }
 340
 341    ir_instruction *inst = NULL;
 342    if (strcmp(tag->value(), "declare") == 0) {
 343       inst = read_declaration(list);
 344    } else if (strcmp(tag->value(), "assign") == 0) {
 345       inst = read_assignment(list);
 346    } else if (strcmp(tag->value(), "if") == 0) {
 347       inst = read_if(list, loop_ctx);
 348    } else if (strcmp(tag->value(), "loop") == 0) {
 349       inst = read_loop(list);
 350    } else if (strcmp(tag->value(), "return") == 0) {
 351       inst = read_return(list);
 352    } else if (strcmp(tag->value(), "function") == 0) {
 353       inst = read_function(list, false);
 354    } else {
 355       inst = read_rvalue(list);
 356       if (inst == NULL)
 357          ir_read_error(NULL, "when reading instruction");
 358    }
 359    return inst;
 360 }
 361
 362 ir_variable *
 363 ir_reader::read_declaration(s_expression *expr)
 364 {
 365    s_list *s_quals;
 366    s_expression *s_type;
 367    s_symbol *s_name;
 368
 369    s_pattern pat[] = { "declare", s_quals, s_type, s_name };
 370    if (!MATCH(expr, pat)) {
 371       ir_read_error(expr, "expected (declare (<qualifiers>) <type> <name>)");
 372       return NULL;
 373    }
 374
 375    const glsl_type *type = read_type(s_type);
 376    if (type == NULL)
 377       return NULL;
 378
 379    ir_variable *var = new(mem_ctx) ir_variable(type, s_name->value(),
 380                                                ir_var_auto);
 381
 382    foreach_iter(exec_list_iterator, it, s_quals->subexpressions) {
 383       s_symbol *qualifier = SX_AS_SYMBOL(it.get());
 384       if (qualifier == NULL) {
 385          ir_read_error(expr, "qualifier list must contain only symbols");
 386          return NULL;
 387       }
 388
 389       // FINISHME: Check for duplicate/conflicting qualifiers.
 390       if (strcmp(qualifier->value(), "centroid") == 0) {
 391          var->centroid = 1;
 392       } else if (strcmp(qualifier->value(), "invariant") == 0) {
 393          var->invariant = 1;
 394       } else if (strcmp(qualifier->value(), "uniform") == 0) {
 395          var->mode = ir_var_uniform;
 396       } else if (strcmp(qualifier->value(), "auto") == 0) {
 397          var->mode = ir_var_auto;
 398       } else if (strcmp(qualifier->value(), "in") == 0) {
 399          var->mode = ir_var_in;
 400       } else if (strcmp(qualifier->value(), "out") == 0) {
 401          var->mode = ir_var_out;
 402       } else if (strcmp(qualifier->value(), "inout") == 0) {
 403          var->mode = ir_var_inout;
 404       } else if (strcmp(qualifier->value(), "smooth") == 0) {
 405          var->interpolation = ir_var_smooth;
 406       } else if (strcmp(qualifier->value(), "flat") == 0) {
 407          var->interpolation = ir_var_flat;
 408       } else if (strcmp(qualifier->value(), "noperspective") == 0) {
 409          var->interpolation = ir_var_noperspective;
 410       } else {
 411          ir_read_error(expr, "unknown qualifier: %s", qualifier->value());
 412          return NULL;
 413       }
 414    }
 415
 416    // Add the variable to the symbol table
 417    state->symbols->add_variable(var);
 418
 419    return var;
 420 }
 421
 422
 423 ir_if *
 424 ir_reader::read_if(s_expression *expr, ir_loop *loop_ctx)
 425 {
 426    s_expression *s_cond;
 427    s_expression *s_then;
 428    s_expression *s_else;
 429
 430    s_pattern pat[] = { "if", s_cond, s_then, s_else };
 431    if (!MATCH(expr, pat)) {
 432       ir_read_error(expr, "expected (if <condition> (<then>...) (<else>...))");
 433       return NULL;
 434    }
 435
 436    ir_rvalue *condition = read_rvalue(s_cond);
 437    if (condition == NULL) {
 438       ir_read_error(NULL, "when reading condition of (if ...)");
 439       return NULL;
 440    }
 441
 442    ir_if *iff = new(mem_ctx) ir_if(condition);
 443
 444    read_instructions(&iff->then_instructions, s_then, loop_ctx);
 445    read_instructions(&iff->else_instructions, s_else, loop_ctx);
 446    if (state->error) {
 447       delete iff;
 448       iff = NULL;
 449    }
 450    return iff;
 451 }
 452
 453
 454 ir_loop *
 455 ir_reader::read_loop(s_expression *expr)
 456 {
 457    s_expression *s_counter, *s_from, *s_to, *s_inc, *s_body;
 458
 459    s_pattern pat[] = { "loop", s_counter, s_from, s_to, s_inc, s_body };
 460    if (!MATCH(expr, pat)) {
 461       ir_read_error(expr, "expected (loop <counter> <from> <to> "
 462                           "<increment> <body>)");
 463       return NULL;
 464    }
 465
 466    // FINISHME: actually read the count/from/to fields.
 467
 468    ir_loop *loop = new(mem_ctx) ir_loop;
 469    read_instructions(&loop->body_instructions, s_body, loop);
 470    if (state->error) {
 471       delete loop;
 472       loop = NULL;
 473    }
 474    return loop;
 475 }
 476
 477
 478 ir_return *
 479 ir_reader::read_return(s_expression *expr)
 480 {
 481    s_expression *s_retval;
 482
 483    s_pattern pat[] = { "return", s_retval};
 484    if (!MATCH(expr, pat)) {
 485       ir_read_error(expr, "expected (return <rvalue>)");
 486       return NULL;
 487    }
 488
 489    ir_rvalue *retval = read_rvalue(s_retval);
 490    if (retval == NULL) {
 491       ir_read_error(NULL, "when reading return value");
 492       return NULL;
 493    }
 494
 495    return new(mem_ctx) ir_return(retval);
 496 }
 497
 498
 499 ir_rvalue *
 500 ir_reader::read_rvalue(s_expression *expr)
 501 {
 502    s_list *list = SX_AS_LIST(expr);
 503    if (list == NULL || list->subexpressions.is_empty())
 504       return NULL;
 505
 506    s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());
 507    if (tag == NULL) {
 508       ir_read_error(expr, "expected rvalue tag");
 509       return NULL;
 510    }
 511
 512    ir_rvalue *rvalue = read_dereference(list);
 513    if (rvalue != NULL || state->error)
 514       return rvalue;
 515    else if (strcmp(tag->value(), "swiz") == 0) {
 516       rvalue = read_swizzle(list);
 517    } else if (strcmp(tag->value(), "expression") == 0) {
 518       rvalue = read_expression(list);
 519    } else if (strcmp(tag->value(), "call") == 0) {
 520       rvalue = read_call(list);
 521    } else if (strcmp(tag->value(), "constant") == 0) {
 522       rvalue = read_constant(list);
 523    } else {
 524       rvalue = read_texture(list);
 525       if (rvalue == NULL && !state->error)
 526          ir_read_error(expr, "unrecognized rvalue tag: %s", tag->value());
 527    }
 528
 529    return rvalue;
 530 }
 531
 532 ir_assignment *
 533 ir_reader::read_assignment(s_expression *expr)
 534 {
 535    s_expression *cond_expr = NULL;
 536    s_expression *lhs_expr, *rhs_expr;
 537    s_list       *mask_list;
 538
 539    s_pattern pat4[] = { "assign",            mask_list, lhs_expr, rhs_expr };
 540    s_pattern pat5[] = { "assign", cond_expr, mask_list, lhs_expr, rhs_expr };
 541    if (!MATCH(expr, pat4) && !MATCH(expr, pat5)) {
 542       ir_read_error(expr, "expected (assign [<condition>] (<write mask>) "
 543                           "<lhs> <rhs>)");
 544       return NULL;
 545    }
 546
 547    ir_rvalue *condition = NULL;
 548    if (cond_expr != NULL) {
 549       condition = read_rvalue(cond_expr);
 550       if (condition == NULL) {
 551          ir_read_error(NULL, "when reading condition of assignment");
 552          return NULL;
 553       }
 554    }
 555
 556    unsigned mask = 0;
 557
 558    s_symbol *mask_symbol;
 559    s_pattern mask_pat[] = { mask_symbol };
 560    if (MATCH(mask_list, mask_pat)) {
 561       const char *mask_str = mask_symbol->value();
 562       unsigned mask_length = strlen(mask_str);
 563       if (mask_length > 4) {
 564          ir_read_error(expr, "invalid write mask: %s", mask_str);
 565          return NULL;
 566       }
 567
 568       const unsigned idx_map[] = { 3, 0, 1, 2 }; /* w=bit 3, x=0, y=1, z=2 */
 569
 570       for (unsigned i = 0; i < mask_length; i++) {
 571          if (mask_str[i] < 'w' || mask_str[i] > 'z') {
 572             ir_read_error(expr, "write mask contains invalid character: %c",
 573                           mask_str[i]);
 574             return NULL;
 575          }
 576          mask |= 1 << idx_map[mask_str[i] - 'w'];
 577       }
 578    } else if (!mask_list->subexpressions.is_empty()) {
 579       ir_read_error(mask_list, "expected () or (<write mask>)");
 580       return NULL;
 581    }
 582
 583    ir_dereference *lhs = read_dereference(lhs_expr);
 584    if (lhs == NULL) {
 585       ir_read_error(NULL, "when reading left-hand side of assignment");
 586       return NULL;
 587    }
 588
 589    ir_rvalue *rhs = read_rvalue(rhs_expr);
 590    if (rhs == NULL) {
 591       ir_read_error(NULL, "when reading right-hand side of assignment");
 592       return NULL;
 593    }
 594
 595    if (mask == 0 && (lhs->type->is_vector() || lhs->type->is_scalar())) {
 596       ir_read_error(expr, "non-zero write mask required.");
 597       return NULL;
 598    }
 599
 600    return new(mem_ctx) ir_assignment(lhs, rhs, condition, mask);
 601 }
 602
 603 ir_call *
 604 ir_reader::read_call(s_expression *expr)
 605 {
 606    s_symbol *name;
 607    s_list *params;
 608
 609    s_pattern pat[] = { "call", name, params };
 610    if (!MATCH(expr, pat)) {
 611       ir_read_error(expr, "expected (call <name> (<param> ...))");
 612       return NULL;
 613    }
 614
 615    exec_list parameters;
 616
 617    foreach_iter(exec_list_iterator, it, params->subexpressions) {
 618       s_expression *expr = (s_expression*) it.get();
 619       ir_rvalue *param = read_rvalue(expr);
 620       if (param == NULL) {
 621          ir_read_error(expr, "when reading parameter to function call");
 622          return NULL;
 623       }
 624       parameters.push_tail(param);
 625    }
 626
 627    ir_function *f = state->symbols->get_function(name->value());
 628    if (f == NULL) {
 629       ir_read_error(expr, "found call to undefined function %s",
 630                     name->value());
 631       return NULL;
 632    }
 633
 634    ir_function_signature *callee = f->matching_signature(&parameters);
 635    if (callee == NULL) {
 636       ir_read_error(expr, "couldn't find matching signature for function "
 637                     "%s", name->value());
 638       return NULL;
 639    }
 640
 641    return new(mem_ctx) ir_call(callee, &parameters);
 642 }
 643
 644 ir_expression *
 645 ir_reader::read_expression(s_expression *expr)
 646 {
 647    s_expression *s_type;
 648    s_symbol *s_op;
 649    s_expression *s_arg1;
 650
 651    s_pattern pat[] = { "expression", s_type, s_op, s_arg1 };
 652    if (!PARTIAL_MATCH(expr, pat)) {
 653       ir_read_error(expr, "expected (expression <type> <operator> "
 654                           "<operand> [<operand>])");
 655       return NULL;
 656    }
 657    s_expression *s_arg2 = (s_expression *) s_arg1->next; // may be tail sentinel
 658
 659    const glsl_type *type = read_type(s_type);
 660    if (type == NULL)
 661       return NULL;
 662
 663    /* Read the operator */
 664    ir_expression_operation op = ir_expression::get_operator(s_op->value());
 665    if (op == (ir_expression_operation) -1) {
 666       ir_read_error(expr, "invalid operator: %s", s_op->value());
 667       return NULL;
 668    }
 669
 670    unsigned num_operands = ir_expression::get_num_operands(op);
 671    if (num_operands == 1 && !s_arg1->next->is_tail_sentinel()) {
 672       ir_read_error(expr, "expected (expression <type> %s <operand>)",
 673                     s_op->value());
 674       return NULL;
 675    }
 676
 677    ir_rvalue *arg1 = read_rvalue(s_arg1);
 678    ir_rvalue *arg2 = NULL;
 679    if (arg1 == NULL) {
 680       ir_read_error(NULL, "when reading first operand of %s", s_op->value());
 681       return NULL;
 682    }
 683
 684    if (num_operands == 2) {
 685       if (s_arg2->is_tail_sentinel() || !s_arg2->next->is_tail_sentinel()) {
 686          ir_read_error(expr, "expected (expression <type> %s <operand> "
 687                              "<operand>)", s_op->value());
 688          return NULL;
 689       }
 690       arg2 = read_rvalue(s_arg2);
 691       if (arg2 == NULL) {
 692          ir_read_error(NULL, "when reading second operand of %s",
 693                        s_op->value());
 694          return NULL;
 695       }
 696    }
 697
 698    return new(mem_ctx) ir_expression(op, type, arg1, arg2);
 699 }
 700
 701 ir_swizzle *
 702 ir_reader::read_swizzle(s_expression *expr)
 703 {
 704    s_symbol *swiz;
 705    s_expression *sub;
 706
 707    s_pattern pat[] = { "swiz", swiz, sub };
 708    if (!MATCH(expr, pat)) {
 709       ir_read_error(expr, "expected (swiz <swizzle> <rvalue>)");
 710       return NULL;
 711    }
 712
 713    if (strlen(swiz->value()) > 4) {
 714       ir_read_error(expr, "expected a valid swizzle; found %s", swiz->value());
 715       return NULL;
 716    }
 717
 718    ir_rvalue *rvalue = read_rvalue(sub);
 719    if (rvalue == NULL)
 720       return NULL;
 721
 722    ir_swizzle *ir = ir_swizzle::create(rvalue, swiz->value(),
 723                                        rvalue->type->vector_elements);
 724    if (ir == NULL)
 725       ir_read_error(expr, "invalid swizzle");
 726
 727    return ir;
 728 }
 729
 730 ir_constant *
 731 ir_reader::read_constant(s_expression *expr)
 732 {
 733    s_expression *type_expr;
 734    s_list *values;
 735
 736    s_pattern pat[] = { "constant", type_expr, values };
 737    if (!MATCH(expr, pat)) {
 738       ir_read_error(expr, "expected (constant <type> (...))");
 739       return NULL;
 740    }
 741
 742    const glsl_type *type = read_type(type_expr);
 743    if (type == NULL)
 744       return NULL;
 745
 746    if (values == NULL) {
 747       ir_read_error(expr, "expected (constant <type> (...))");
 748       return NULL;
 749    }
 750
 751    if (type->is_array()) {
 752       unsigned elements_supplied = 0;
 753       exec_list elements;
 754       foreach_iter(exec_list_iterator, it, values->subexpressions) {
 755          s_expression *elt = (s_expression *) it.get();
 756          ir_constant *ir_elt = read_constant(elt);
 757          if (ir_elt == NULL)
 758             return NULL;
 759          elements.push_tail(ir_elt);
 760          elements_supplied++;
 761       }
 762
 763       if (elements_supplied != type->length) {
 764          ir_read_error(values, "expected exactly %u array elements, "
 765                        "given %u", type->length, elements_supplied);
 766          return NULL;
 767       }
 768       return new(mem_ctx) ir_constant(type, &elements);
 769    }
 770
 771    const glsl_type *const base_type = type->get_base_type();
 772
 773    ir_constant_data data = { { 0 } };
 774
 775    // Read in list of values (at most 16).
 776    int k = 0;
 777    foreach_iter(exec_list_iterator, it, values->subexpressions) {
 778       if (k >= 16) {
 779          ir_read_error(values, "expected at most 16 numbers");
 780          return NULL;
 781       }
 782
 783       s_expression *expr = (s_expression*) it.get();
 784
 785       if (base_type->base_type == GLSL_TYPE_FLOAT) {
 786          s_number *value = SX_AS_NUMBER(expr);
 787          if (value == NULL) {
 788             ir_read_error(values, "expected numbers");
 789             return NULL;
 790          }
 791          data.f[k] = value->fvalue();
 792       } else {
 793          s_int *value = SX_AS_INT(expr);
 794          if (value == NULL) {
 795             ir_read_error(values, "expected integers");
 796             return NULL;
 797          }
 798
 799          switch (base_type->base_type) {
 800          case GLSL_TYPE_UINT: {
 801             data.u[k] = value->value();
 802             break;
 803          }
 804          case GLSL_TYPE_INT: {
 805             data.i[k] = value->value();
 806             break;
 807          }
 808          case GLSL_TYPE_BOOL: {
 809             data.b[k] = value->value();
 810             break;
 811          }
 812          default:
 813             ir_read_error(values, "unsupported constant type");
 814             return NULL;
 815          }
 816       }
 817       ++k;
 818    }
 819
 820    return new(mem_ctx) ir_constant(type, &data);
 821 }
 822
 823 ir_dereference *
 824 ir_reader::read_dereference(s_expression *expr)
 825 {
 826    s_symbol *s_var;
 827    s_expression *s_subject;
 828    s_expression *s_index;
 829    s_symbol *s_field;
 830
 831    s_pattern var_pat[] = { "var_ref", s_var };
 832    s_pattern array_pat[] = { "array_ref", s_subject, s_index };
 833    s_pattern record_pat[] = { "record_ref", s_subject, s_field };
 834
 835    if (MATCH(expr, var_pat)) {
 836       ir_variable *var = state->symbols->get_variable(s_var->value());
 837       if (var == NULL) {
 838          ir_read_error(expr, "undeclared variable: %s", s_var->value());
 839          return NULL;
 840       }
 841       return new(mem_ctx) ir_dereference_variable(var);
 842    } else if (MATCH(expr, array_pat)) {
 843       ir_rvalue *subject = read_rvalue(s_subject);
 844       if (subject == NULL) {
 845          ir_read_error(NULL, "when reading the subject of an array_ref");
 846          return NULL;
 847       }
 848
 849       ir_rvalue *idx = read_rvalue(s_index);
 850       if (subject == NULL) {
 851          ir_read_error(NULL, "when reading the index of an array_ref");
 852          return NULL;
 853       }
 854       return new(mem_ctx) ir_dereference_array(subject, idx);
 855    } else if (MATCH(expr, record_pat)) {
 856       ir_rvalue *subject = read_rvalue(s_subject);
 857       if (subject == NULL) {
 858          ir_read_error(NULL, "when reading the subject of a record_ref");
 859          return NULL;
 860       }
 861       return new(mem_ctx) ir_dereference_record(subject, s_field->value());
 862    }
 863    return NULL;
 864 }
 865
 866 ir_texture *
 867 ir_reader::read_texture(s_expression *expr)
 868 {
 869    s_symbol *tag = NULL;
 870    s_expression *s_sampler = NULL;
 871    s_expression *s_coord = NULL;
 872    s_list *s_offset = NULL;
 873    s_expression *s_proj = NULL;
 874    s_list *s_shadow = NULL;
 875    s_expression *s_lod = NULL;
 876
 877    ir_texture_opcode op = ir_tex; /* silence warning */
 878
 879    s_pattern tex_pattern[] =
 880       { "tex", s_sampler, s_coord, s_offset, s_proj, s_shadow };
 881    s_pattern txf_pattern[] =
 882       { "txf", s_sampler, s_coord, s_offset, s_lod };
 883    s_pattern other_pattern[] =
 884       { tag, s_sampler, s_coord, s_offset, s_proj, s_shadow, s_lod };
 885
 886    if (MATCH(expr, tex_pattern)) {
 887       op = ir_tex;
 888    } else if (MATCH(expr, txf_pattern)) {
 889       op = ir_txf;
 890    } else if (MATCH(expr, other_pattern)) {
 891       op = ir_texture::get_opcode(tag->value());
 892       if (op == -1)
 893          return NULL;
 894    } else {
 895       ir_read_error(NULL, "unexpected texture pattern");
 896       return NULL;
 897    }
 898
 899    ir_texture *tex = new(mem_ctx) ir_texture(op);
 900
 901    // Read sampler (must be a deref)
 902    ir_dereference *sampler = read_dereference(s_sampler);
 903    if (sampler == NULL) {
 904       ir_read_error(NULL, "when reading sampler in (%s ...)",
 905                     tex->opcode_string());
 906       return NULL;
 907    }
 908    tex->set_sampler(sampler);
 909
 910    // Read coordinate (any rvalue)
 911    tex->coordinate = read_rvalue(s_coord);
 912    if (tex->coordinate == NULL) {
 913       ir_read_error(NULL, "when reading coordinate in (%s ...)",
 914                     tex->opcode_string());
 915       return NULL;
 916    }
 917
 918    // Read texel offset, i.e. (0 0 0)
 919    s_int *offset_x;
 920    s_int *offset_y;
 921    s_int *offset_z;
 922    s_pattern offset_pat[] = { offset_x, offset_y, offset_z };
 923    if (!MATCH(s_offset, offset_pat)) {
 924       ir_read_error(s_offset, "expected (<int> <int> <int>)");
 925       return NULL;
 926    }
 927    tex->offsets[0] = offset_x->value();
 928    tex->offsets[1] = offset_y->value();
 929    tex->offsets[2] = offset_z->value();
 930
 931    if (op != ir_txf) {
 932       s_int *proj_as_int = SX_AS_INT(s_proj);
 933       if (proj_as_int && proj_as_int->value() == 1) {
 934          tex->projector = NULL;
 935       } else {
 936          tex->projector = read_rvalue(s_proj);
 937          if (tex->projector == NULL) {
 938             ir_read_error(NULL, "when reading projective divide in (%s ..)",
 939                           tex->opcode_string());
 940             return NULL;
 941          }
 942       }
 943
 944       if (s_shadow->subexpressions.is_empty()) {
 945          tex->shadow_comparitor = NULL;
 946       } else {
 947          tex->shadow_comparitor = read_rvalue(s_shadow);
 948          if (tex->shadow_comparitor == NULL) {
 949             ir_read_error(NULL, "when reading shadow comparitor in (%s ..)",
 950                           tex->opcode_string());
 951             return NULL;
 952          }
 953       }
 954    }
 955
 956    switch (op) {
 957    case ir_txb:
 958       tex->lod_info.bias = read_rvalue(s_lod);
 959       if (tex->lod_info.bias == NULL) {
 960          ir_read_error(NULL, "when reading LOD bias in (txb ...)");
 961          return NULL;
 962       }
 963       break;
 964    case ir_txl:
 965    case ir_txf:
 966       tex->lod_info.lod = read_rvalue(s_lod);
 967       if (tex->lod_info.lod == NULL) {
 968          ir_read_error(NULL, "when reading LOD in (%s ...)",
 969                        tex->opcode_string());
 970          return NULL;
 971       }
 972       break;
 973    case ir_txd: {
 974       s_expression *s_dx, *s_dy;
 975       s_pattern dxdy_pat[] = { s_dx, s_dy };
 976       if (!MATCH(s_lod, dxdy_pat)) {
 977          ir_read_error(s_lod, "expected (dPdx dPdy) in (txd ...)");
 978          return NULL;
 979       }
 980       tex->lod_info.grad.dPdx = read_rvalue(s_dx);
 981       if (tex->lod_info.grad.dPdx == NULL) {
 982          ir_read_error(NULL, "when reading dPdx in (txd ...)");
 983          return NULL;
 984       }
 985       tex->lod_info.grad.dPdy = read_rvalue(s_dy);
 986       if (tex->lod_info.grad.dPdy == NULL) {
 987          ir_read_error(NULL, "when reading dPdy in (txd ...)");
 988          return NULL;
 989       }
 990       break;
 991    }
 992    default:
 993       // tex doesn't have any extra parameters.
 994       break;
 995    };
 996    return tex;
 997 }