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  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 <stdarg.h>
  25.  
  26. #include "ir_reader.h"
  27. #include "glsl_parser_extras.h"
  28. #include "glsl_types.h"
  29. #include "s_expression.h"
  30.  
  31. const static bool debug = false;
  32.  
  33. static void ir_read_error(_mesa_glsl_parse_state *, s_expression *,
  34.                           const char *fmt, ...);
  35. static const glsl_type *read_type(_mesa_glsl_parse_state *, s_expression *);
  36.  
  37. static void scan_for_prototypes(_mesa_glsl_parse_state *, exec_list *,
  38.                                 s_expression *);
  39. static ir_function *read_function(_mesa_glsl_parse_state *, s_list *,
  40.                                   bool skip_body);
  41. static void read_function_sig(_mesa_glsl_parse_state *, ir_function *,
  42.                               s_list *, bool skip_body);
  43.  
  44. static void read_instructions(_mesa_glsl_parse_state *, exec_list *,
  45.                               s_expression *, ir_loop *);
  46. static ir_instruction *read_instruction(_mesa_glsl_parse_state *,
  47.                                         s_expression *, ir_loop *);
  48. static ir_variable *read_declaration(_mesa_glsl_parse_state *, s_list *);
  49. static ir_if *read_if(_mesa_glsl_parse_state *, s_list *, ir_loop *);
  50. static ir_loop *read_loop(_mesa_glsl_parse_state *st, s_list *list);
  51. static ir_return *read_return(_mesa_glsl_parse_state *, s_list *);
  52.  
  53. static ir_rvalue *read_rvalue(_mesa_glsl_parse_state *, s_expression *);
  54. static ir_assignment *read_assignment(_mesa_glsl_parse_state *, s_list *);
  55. static ir_expression *read_expression(_mesa_glsl_parse_state *, s_list *);
  56. static ir_call *read_call(_mesa_glsl_parse_state *, s_list *);
  57. static ir_swizzle *read_swizzle(_mesa_glsl_parse_state *, s_list *);
  58. static ir_constant *read_constant(_mesa_glsl_parse_state *, s_list *);
  59. static ir_texture *read_texture(_mesa_glsl_parse_state *, s_list *);
  60.  
  61. static ir_dereference *read_dereference(_mesa_glsl_parse_state *,
  62.                                         s_expression *);
  63. static ir_dereference_variable *
  64. read_var_ref(_mesa_glsl_parse_state *, s_list *);
  65. static ir_dereference_array *
  66. read_array_ref(_mesa_glsl_parse_state *, s_list *);
  67. static ir_dereference_record *
  68. read_record_ref(_mesa_glsl_parse_state *, s_list *);
  69.  
  70. void
  71. _mesa_glsl_read_ir(_mesa_glsl_parse_state *state, exec_list *instructions,
  72.                    const char *src, bool scan_for_protos)
  73. {
  74.    s_expression *expr = s_expression::read_expression(state, src);
  75.    if (expr == NULL) {
  76.       ir_read_error(state, NULL, "couldn't parse S-Expression.");
  77.       return;
  78.    }
  79.    
  80.    if (scan_for_protos) {
  81.       scan_for_prototypes(state, instructions, expr);
  82.       if (state->error)
  83.          return;
  84.    }
  85.  
  86.    read_instructions(state, instructions, expr, NULL);
  87.    ralloc_free(expr);
  88.  
  89.    if (debug)
  90.       validate_ir_tree(instructions);
  91. }
  92.  
  93. static void
  94. ir_read_error(_mesa_glsl_parse_state *state, s_expression *expr,
  95.               const char *fmt, ...)
  96. {
  97.    va_list ap;
  98.  
  99.    state->error = true;
  100.  
  101.    if (state->current_function != NULL)
  102.       ralloc_asprintf_append(&state->info_log, "In function %s:\n",
  103.                              state->current_function->function_name());
  104.    ralloc_strcat(&state->info_log, "error: ");
  105.  
  106.    va_start(ap, fmt);
  107.    ralloc_vasprintf_append(&state->info_log, fmt, ap);
  108.    va_end(ap);
  109.    ralloc_strcat(&state->info_log, "\n");
  110.  
  111.    if (expr != NULL) {
  112.       ralloc_strcat(&state->info_log, "...in this context:\n   ");
  113.       expr->print();
  114.       ralloc_strcat(&state->info_log, "\n\n");
  115.    }
  116. }
  117.  
  118. static const glsl_type *
  119. read_type(_mesa_glsl_parse_state *st, s_expression *expr)
  120. {
  121.    s_list *list = SX_AS_LIST(expr);
  122.    if (list != NULL) {
  123.       s_symbol *type_sym = SX_AS_SYMBOL(list->subexpressions.get_head());
  124.       if (type_sym == NULL) {
  125.          ir_read_error(st, expr, "expected type (array ...) or (struct ...)");
  126.          return NULL;
  127.       }
  128.       if (strcmp(type_sym->value(), "array") == 0) {
  129.          if (list->length() != 3) {
  130.             ir_read_error(st, expr, "expected type (array <type> <int>)");
  131.             return NULL;
  132.          }
  133.  
  134.          // Read base type
  135.          s_expression *base_expr = (s_expression*) type_sym->next;
  136.          const glsl_type *base_type = read_type(st, base_expr);
  137.          if (base_type == NULL) {
  138.             ir_read_error(st, NULL, "when reading base type of array");
  139.             return NULL;
  140.          }
  141.  
  142.          // Read array size
  143.          s_int *size = SX_AS_INT(base_expr->next);
  144.          if (size == NULL) {
  145.             ir_read_error(st, expr, "found non-integer array size");
  146.             return NULL;
  147.          }
  148.  
  149.          return glsl_type::get_array_instance(base_type, size->value());
  150.       } else if (strcmp(type_sym->value(), "struct") == 0) {
  151.          assert(false); // FINISHME
  152.       } else {
  153.          ir_read_error(st, expr, "expected (array ...) or (struct ...); "
  154.                                  "found (%s ...)", type_sym->value());
  155.          return NULL;
  156.       }
  157.    }
  158.    
  159.    s_symbol *type_sym = SX_AS_SYMBOL(expr);
  160.    if (type_sym == NULL) {
  161.       ir_read_error(st, expr, "expected <type> (symbol or list)");
  162.       return NULL;
  163.    }
  164.  
  165.    const glsl_type *type = st->symbols->get_type(type_sym->value());
  166.    if (type == NULL)
  167.       ir_read_error(st, expr, "invalid type: %s", type_sym->value());
  168.  
  169.    return type;
  170. }
  171.  
  172.  
  173. static void
  174. scan_for_prototypes(_mesa_glsl_parse_state *st, exec_list *instructions,
  175.                     s_expression *expr)
  176. {
  177.    s_list *list = SX_AS_LIST(expr);
  178.    if (list == NULL) {
  179.       ir_read_error(st, expr, "Expected (<instruction> ...); found an atom.");
  180.       return;
  181.    }
  182.  
  183.    foreach_iter(exec_list_iterator, it, list->subexpressions) {
  184.       s_list *sub = SX_AS_LIST(it.get());
  185.       if (sub == NULL)
  186.          continue; // not a (function ...); ignore it.
  187.  
  188.       s_symbol *tag = SX_AS_SYMBOL(sub->subexpressions.get_head());
  189.       if (tag == NULL || strcmp(tag->value(), "function") != 0)
  190.          continue; // not a (function ...); ignore it.
  191.  
  192.       ir_function *f = read_function(st, sub, true);
  193.       if (f == NULL)
  194.          return;
  195.       instructions->push_tail(f);
  196.    }
  197. }
  198.  
  199. static ir_function *
  200. read_function(_mesa_glsl_parse_state *st, s_list *list, bool skip_body)
  201. {
  202.    void *ctx = st;
  203.    bool added = false;
  204.    if (list->length() < 3) {
  205.       ir_read_error(st, list, "Expected (function <name> (signature ...) ...)");
  206.       return NULL;
  207.    }
  208.  
  209.    s_symbol *name = SX_AS_SYMBOL(list->subexpressions.head->next);
  210.    if (name == NULL) {
  211.       ir_read_error(st, list, "Expected (function <name> ...)");
  212.       return NULL;
  213.    }
  214.  
  215.    ir_function *f = st->symbols->get_function(name->value());
  216.    if (f == NULL) {
  217.       f = new(ctx) ir_function(name->value());
  218.       added = st->symbols->add_function(f);
  219.       assert(added);
  220.    }
  221.  
  222.    exec_list_iterator it = list->subexpressions.iterator();
  223.    it.next(); // skip "function" tag
  224.    it.next(); // skip function name
  225.    for (/* nothing */; it.has_next(); it.next()) {
  226.       s_list *siglist = SX_AS_LIST(it.get());
  227.       if (siglist == NULL) {
  228.          ir_read_error(st, list, "Expected (function (signature ...) ...)");
  229.          return NULL;
  230.       }
  231.  
  232.       s_symbol *tag = SX_AS_SYMBOL(siglist->subexpressions.get_head());
  233.       if (tag == NULL || strcmp(tag->value(), "signature") != 0) {
  234.          ir_read_error(st, siglist, "Expected (signature ...)");
  235.          return NULL;
  236.       }
  237.  
  238.       read_function_sig(st, f, siglist, skip_body);
  239.    }
  240.    return added ? f : NULL;
  241. }
  242.  
  243. static void
  244. read_function_sig(_mesa_glsl_parse_state *st, ir_function *f, s_list *list,
  245.                   bool skip_body)
  246. {
  247.    void *ctx = st;
  248.    if (list->length() != 4) {
  249.       ir_read_error(st, list, "Expected (signature <type> (parameters ...) "
  250.                               "(<instruction> ...))");
  251.       return;
  252.    }
  253.  
  254.    s_expression *type_expr = (s_expression*) list->subexpressions.head->next;
  255.    const glsl_type *return_type = read_type(st, type_expr);
  256.    if (return_type == NULL)
  257.       return;
  258.  
  259.    s_list *paramlist = SX_AS_LIST(type_expr->next);
  260.    s_list *body_list = SX_AS_LIST(type_expr->next->next);
  261.    if (paramlist == NULL || body_list == NULL) {
  262.       ir_read_error(st, list, "Expected (signature <type> (parameters ...) "
  263.                               "(<instruction> ...))");
  264.       return;
  265.    }
  266.    s_symbol *paramtag = SX_AS_SYMBOL(paramlist->subexpressions.get_head());
  267.    if (paramtag == NULL || strcmp(paramtag->value(), "parameters") != 0) {
  268.       ir_read_error(st, paramlist, "Expected (parameters ...)");
  269.       return;
  270.    }
  271.  
  272.    // Read the parameters list into a temporary place.
  273.    exec_list hir_parameters;
  274.    st->symbols->push_scope();
  275.  
  276.    exec_list_iterator it = paramlist->subexpressions.iterator();
  277.    for (it.next() /* skip "parameters" */; it.has_next(); it.next()) {
  278.       s_list *decl = SX_AS_LIST(it.get());
  279.       ir_variable *var = read_declaration(st, decl);
  280.       if (var == NULL)
  281.          return;
  282.  
  283.       hir_parameters.push_tail(var);
  284.    }
  285.  
  286.    ir_function_signature *sig = f->exact_matching_signature(&hir_parameters);
  287.    if (sig == NULL && skip_body) {
  288.       /* If scanning for prototypes, generate a new signature. */
  289.       sig = new(ctx) ir_function_signature(return_type);
  290.       sig->is_builtin = true;
  291.       f->add_signature(sig);
  292.    } else if (sig != NULL) {
  293.       const char *badvar = sig->qualifiers_match(&hir_parameters);
  294.       if (badvar != NULL) {
  295.          ir_read_error(st, list, "function `%s' parameter `%s' qualifiers "
  296.                        "don't match prototype", f->name, badvar);
  297.          return;
  298.       }
  299.  
  300.       if (sig->return_type != return_type) {
  301.          ir_read_error(st, list, "function `%s' return type doesn't "
  302.                        "match prototype", f->name);
  303.          return;
  304.       }
  305.    } else {
  306.       /* No prototype for this body exists - skip it. */
  307.       st->symbols->pop_scope();
  308.       return;
  309.    }
  310.    assert(sig != NULL);
  311.  
  312.    sig->replace_parameters(&hir_parameters);
  313.  
  314.    if (!skip_body && !body_list->subexpressions.is_empty()) {
  315.       if (sig->is_defined) {
  316.          ir_read_error(st, list, "function %s redefined", f->name);
  317.          return;
  318.       }
  319.       st->current_function = sig;
  320.       read_instructions(st, &sig->body, body_list, NULL);
  321.       st->current_function = NULL;
  322.       sig->is_defined = true;
  323.    }
  324.  
  325.    st->symbols->pop_scope();
  326. }
  327.  
  328. static void
  329. read_instructions(_mesa_glsl_parse_state *st, exec_list *instructions,
  330.                   s_expression *expr, ir_loop *loop_ctx)
  331. {
  332.    // Read in a list of instructions
  333.    s_list *list = SX_AS_LIST(expr);
  334.    if (list == NULL) {
  335.       ir_read_error(st, expr, "Expected (<instruction> ...); found an atom.");
  336.       return;
  337.    }
  338.  
  339.    foreach_iter(exec_list_iterator, it, list->subexpressions) {
  340.       s_expression *sub = (s_expression*) it.get();
  341.       ir_instruction *ir = read_instruction(st, sub, loop_ctx);
  342.       if (ir != NULL) {
  343.          /* Global variable declarations should be moved to the top, before
  344.           * any functions that might use them.  Functions are added to the
  345.           * instruction stream when scanning for prototypes, so without this
  346.           * hack, they always appear before variable declarations.
  347.           */
  348.          if (st->current_function == NULL && ir->as_variable() != NULL)
  349.             instructions->push_head(ir);
  350.          else
  351.             instructions->push_tail(ir);
  352.       }
  353.    }
  354. }
  355.  
  356.  
  357. static ir_instruction *
  358. read_instruction(_mesa_glsl_parse_state *st, s_expression *expr,
  359.                  ir_loop *loop_ctx)
  360. {
  361.    void *ctx = st;
  362.    s_symbol *symbol = SX_AS_SYMBOL(expr);
  363.    if (symbol != NULL) {
  364.       if (strcmp(symbol->value(), "break") == 0 && loop_ctx != NULL)
  365.          return new(ctx) ir_loop_jump(ir_loop_jump::jump_break);
  366.       if (strcmp(symbol->value(), "continue") == 0 && loop_ctx != NULL)
  367.          return new(ctx) ir_loop_jump(ir_loop_jump::jump_continue);
  368.    }
  369.  
  370.    s_list *list = SX_AS_LIST(expr);
  371.    if (list == NULL || list->subexpressions.is_empty()) {
  372.       ir_read_error(st, expr, "Invalid instruction.\n");
  373.       return NULL;
  374.    }
  375.  
  376.    s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());
  377.    if (tag == NULL) {
  378.       ir_read_error(st, expr, "expected instruction tag");
  379.       return NULL;
  380.    }
  381.  
  382.    ir_instruction *inst = NULL;
  383.    if (strcmp(tag->value(), "declare") == 0) {
  384.       inst = read_declaration(st, list);
  385.    } else if (strcmp(tag->value(), "assign") == 0) {
  386.       inst = read_assignment(st, list);
  387.    } else if (strcmp(tag->value(), "if") == 0) {
  388.       inst = read_if(st, list, loop_ctx);
  389.    } else if (strcmp(tag->value(), "loop") == 0) {
  390.       inst = read_loop(st, list);
  391.    } else if (strcmp(tag->value(), "return") == 0) {
  392.       inst = read_return(st, list);
  393.    } else if (strcmp(tag->value(), "function") == 0) {
  394.       inst = read_function(st, list, false);
  395.    } else {
  396.       inst = read_rvalue(st, list);
  397.       if (inst == NULL)
  398.          ir_read_error(st, NULL, "when reading instruction");
  399.    }
  400.    return inst;
  401. }
  402.  
  403.  
  404. static ir_variable *
  405. read_declaration(_mesa_glsl_parse_state *st, s_list *list)
  406. {
  407.    void *ctx = st;
  408.    if (list->length() != 4) {
  409.       ir_read_error(st, list, "expected (declare (<qualifiers>) <type> "
  410.                               "<name>)");
  411.       return NULL;
  412.    }
  413.  
  414.    s_list *quals = SX_AS_LIST(list->subexpressions.head->next);
  415.    if (quals == NULL) {
  416.       ir_read_error(st, list, "expected a list of variable qualifiers");
  417.       return NULL;
  418.    }
  419.  
  420.    s_expression *type_expr = (s_expression*) quals->next;
  421.    const glsl_type *type = read_type(st, type_expr);
  422.    if (type == NULL)
  423.       return NULL;
  424.  
  425.    s_symbol *var_name = SX_AS_SYMBOL(type_expr->next);
  426.    if (var_name == NULL) {
  427.       ir_read_error(st, list, "expected variable name, found non-symbol");
  428.       return NULL;
  429.    }
  430.  
  431.    ir_variable *var = new(ctx) ir_variable(type, var_name->value(),
  432.                                            ir_var_auto);
  433.  
  434.    foreach_iter(exec_list_iterator, it, quals->subexpressions) {
  435.       s_symbol *qualifier = SX_AS_SYMBOL(it.get());
  436.       if (qualifier == NULL) {
  437.          ir_read_error(st, list, "qualifier list must contain only symbols");
  438.          delete var;
  439.          return NULL;
  440.       }
  441.  
  442.       // FINISHME: Check for duplicate/conflicting qualifiers.
  443.       if (strcmp(qualifier->value(), "centroid") == 0) {
  444.          var->centroid = 1;
  445.       } else if (strcmp(qualifier->value(), "invariant") == 0) {
  446.          var->invariant = 1;
  447.       } else if (strcmp(qualifier->value(), "uniform") == 0) {
  448.          var->mode = ir_var_uniform;
  449.       } else if (strcmp(qualifier->value(), "auto") == 0) {
  450.          var->mode = ir_var_auto;
  451.       } else if (strcmp(qualifier->value(), "in") == 0) {
  452.          var->mode = ir_var_in;
  453.       } else if (strcmp(qualifier->value(), "out") == 0) {
  454.          var->mode = ir_var_out;
  455.       } else if (strcmp(qualifier->value(), "inout") == 0) {
  456.          var->mode = ir_var_inout;
  457.       } else if (strcmp(qualifier->value(), "smooth") == 0) {
  458.          var->interpolation = ir_var_smooth;
  459.       } else if (strcmp(qualifier->value(), "flat") == 0) {
  460.          var->interpolation = ir_var_flat;
  461.       } else if (strcmp(qualifier->value(), "noperspective") == 0) {
  462.          var->interpolation = ir_var_noperspective;
  463.       } else {
  464.          ir_read_error(st, list, "unknown qualifier: %s", qualifier->value());
  465.          delete var;
  466.          return NULL;
  467.       }
  468.    }
  469.  
  470.    // Add the variable to the symbol table
  471.    st->symbols->add_variable(var);
  472.  
  473.    return var;
  474. }
  475.  
  476.  
  477. static ir_if *
  478. read_if(_mesa_glsl_parse_state *st, s_list *list, ir_loop *loop_ctx)
  479. {
  480.    void *ctx = st;
  481.    if (list->length() != 4) {
  482.       ir_read_error(st, list, "expected (if <condition> (<then> ...) "
  483.                           "(<else> ...))");
  484.       return NULL;
  485.    }
  486.  
  487.    s_expression *cond_expr = (s_expression*) list->subexpressions.head->next;
  488.    ir_rvalue *condition = read_rvalue(st, cond_expr);
  489.    if (condition == NULL) {
  490.       ir_read_error(st, NULL, "when reading condition of (if ...)");
  491.       return NULL;
  492.    }
  493.  
  494.    s_expression *then_expr = (s_expression*) cond_expr->next;
  495.    s_expression *else_expr = (s_expression*) then_expr->next;
  496.  
  497.    ir_if *iff = new(ctx) ir_if(condition);
  498.  
  499.    read_instructions(st, &iff->then_instructions, then_expr, loop_ctx);
  500.    read_instructions(st, &iff->else_instructions, else_expr, loop_ctx);
  501.    if (st->error) {
  502.       delete iff;
  503.       iff = NULL;
  504.    }
  505.    return iff;
  506. }
  507.  
  508.  
  509. static ir_loop *
  510. read_loop(_mesa_glsl_parse_state *st, s_list *list)
  511. {
  512.    void *ctx = st;
  513.    if (list->length() != 6) {
  514.       ir_read_error(st, list, "expected (loop <counter> <from> <to> "
  515.                               "<increment> <body>)");
  516.       return NULL;
  517.    }
  518.  
  519.    s_expression *count_expr = (s_expression*) list->subexpressions.head->next;
  520.    s_expression *from_expr  = (s_expression*) count_expr->next;
  521.    s_expression *to_expr    = (s_expression*) from_expr->next;
  522.    s_expression *inc_expr   = (s_expression*) to_expr->next;
  523.    s_expression *body_expr  = (s_expression*) inc_expr->next;
  524.  
  525.    // FINISHME: actually read the count/from/to fields.
  526.  
  527.    ir_loop *loop = new(ctx) ir_loop;
  528.    read_instructions(st, &loop->body_instructions, body_expr, loop);
  529.    if (st->error) {
  530.       delete loop;
  531.       loop = NULL;
  532.    }
  533.    return loop;
  534. }
  535.  
  536.  
  537. static ir_return *
  538. read_return(_mesa_glsl_parse_state *st, s_list *list)
  539. {
  540.    void *ctx = st;
  541.    if (list->length() != 2) {
  542.       ir_read_error(st, list, "expected (return <rvalue>)");
  543.       return NULL;
  544.    }
  545.  
  546.    s_expression *expr = (s_expression*) list->subexpressions.head->next;
  547.  
  548.    ir_rvalue *retval = read_rvalue(st, expr);
  549.    if (retval == NULL) {
  550.       ir_read_error(st, NULL, "when reading return value");
  551.       return NULL;
  552.    }
  553.  
  554.    return new(ctx) ir_return(retval);
  555. }
  556.  
  557.  
  558. static ir_rvalue *
  559. read_rvalue(_mesa_glsl_parse_state *st, s_expression *expr)
  560. {
  561.    s_list *list = SX_AS_LIST(expr);
  562.    if (list == NULL || list->subexpressions.is_empty())
  563.       return NULL;
  564.  
  565.    s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());
  566.    if (tag == NULL) {
  567.       ir_read_error(st, expr, "expected rvalue tag");
  568.       return NULL;
  569.    }
  570.  
  571.    ir_rvalue *rvalue = read_dereference(st, list);
  572.    if (rvalue != NULL || st->error)
  573.       return rvalue;
  574.    else if (strcmp(tag->value(), "swiz") == 0) {
  575.       rvalue = read_swizzle(st, list);
  576.    } else if (strcmp(tag->value(), "expression") == 0) {
  577.       rvalue = read_expression(st, list);
  578.    } else if (strcmp(tag->value(), "call") == 0) {
  579.       rvalue = read_call(st, list);
  580.    } else if (strcmp(tag->value(), "constant") == 0) {
  581.       rvalue = read_constant(st, list);
  582.    } else {
  583.       rvalue = read_texture(st, list);
  584.       if (rvalue == NULL && !st->error)
  585.          ir_read_error(st, expr, "unrecognized rvalue tag: %s", tag->value());
  586.    }
  587.  
  588.    return rvalue;
  589. }
  590.  
  591. static ir_assignment *
  592. read_assignment(_mesa_glsl_parse_state *st, s_list *list)
  593. {
  594.    void *ctx = st;
  595.    if (list->length() != 5) {
  596.       ir_read_error(st, list, "expected (assign <condition> (<write mask>) "
  597.                               "<lhs> <rhs>)");
  598.       return NULL;
  599.    }
  600.  
  601.    s_expression *cond_expr = (s_expression*) list->subexpressions.head->next;
  602.    s_list       *mask_list = SX_AS_LIST(cond_expr->next);
  603.    s_expression *lhs_expr  = (s_expression*) cond_expr->next->next;
  604.    s_expression *rhs_expr  = (s_expression*) lhs_expr->next;
  605.  
  606.    ir_rvalue *condition = read_rvalue(st, cond_expr);
  607.    if (condition == NULL) {
  608.       ir_read_error(st, NULL, "when reading condition of assignment");
  609.       return NULL;
  610.    }
  611.  
  612.    if (mask_list == NULL || mask_list->length() > 1) {
  613.       ir_read_error(st, mask_list, "expected () or (<write mask>)");
  614.       return NULL;
  615.    }
  616.  
  617.    unsigned mask = 0;
  618.    if (mask_list->length() == 1) {
  619.       s_symbol *mask_symbol = SX_AS_SYMBOL(mask_list->subexpressions.head);
  620.       if (mask_symbol == NULL) {
  621.          ir_read_error(st, list, "expected a write mask; found non-symbol");
  622.          return NULL;
  623.       }
  624.  
  625.       const char *mask_str = mask_symbol->value();
  626.       unsigned mask_length = strlen(mask_str);
  627.       if (mask_length > 4) {
  628.          ir_read_error(st, list, "invalid write mask: %s", mask_str);
  629.          return NULL;
  630.       }
  631.  
  632.       const unsigned idx_map[] = { 3, 0, 1, 2 }; /* w=bit 3, x=0, y=1, z=2 */
  633.  
  634.       for (unsigned i = 0; i < mask_length; i++) {
  635.          if (mask_str[i] < 'w' || mask_str[i] > 'z') {
  636.             ir_read_error(st, list, "write mask contains invalid character: %c",
  637.                           mask_str[i]);
  638.             return NULL;
  639.          }
  640.          mask |= 1 << idx_map[mask_str[i] - 'w'];
  641.       }
  642.    }
  643.  
  644.    ir_dereference *lhs = read_dereference(st, lhs_expr);
  645.    if (lhs == NULL) {
  646.       ir_read_error(st, NULL, "when reading left-hand side of assignment");
  647.       return NULL;
  648.    }
  649.  
  650.    ir_rvalue *rhs = read_rvalue(st, rhs_expr);
  651.    if (rhs == NULL) {
  652.       ir_read_error(st, NULL, "when reading right-hand side of assignment");
  653.       return NULL;
  654.    }
  655.  
  656.    if (mask == 0 && (lhs->type->is_vector() || lhs->type->is_scalar())) {
  657.       ir_read_error(st, list, "non-zero write mask required.");
  658.       return NULL;
  659.    }
  660.  
  661.    return new(ctx) ir_assignment(lhs, rhs, condition, mask);
  662. }
  663.  
  664. static ir_call *
  665. read_call(_mesa_glsl_parse_state *st, s_list *list)
  666. {
  667.    void *ctx = st;
  668.    if (list->length() != 3) {
  669.       ir_read_error(st, list, "expected (call <name> (<param> ...))");
  670.       return NULL;
  671.    }
  672.  
  673.    s_symbol *name = SX_AS_SYMBOL(list->subexpressions.head->next);
  674.    s_list *params = SX_AS_LIST(list->subexpressions.head->next->next);
  675.    if (name == NULL || params == NULL) {
  676.       ir_read_error(st, list, "expected (call <name> (<param> ...))");
  677.       return NULL;
  678.    }
  679.  
  680.    exec_list parameters;
  681.  
  682.    foreach_iter(exec_list_iterator, it, params->subexpressions) {
  683.       s_expression *expr = (s_expression*) it.get();
  684.       ir_rvalue *param = read_rvalue(st, expr);
  685.       if (param == NULL) {
  686.          ir_read_error(st, list, "when reading parameter to function call");
  687.          return NULL;
  688.       }
  689.       parameters.push_tail(param);
  690.    }
  691.  
  692.    ir_function *f = st->symbols->get_function(name->value());
  693.    if (f == NULL) {
  694.       ir_read_error(st, list, "found call to undefined function %s",
  695.                     name->value());
  696.       return NULL;
  697.    }
  698.  
  699.    ir_function_signature *callee = f->matching_signature(&parameters);
  700.    if (callee == NULL) {
  701.       ir_read_error(st, list, "couldn't find matching signature for function "
  702.                     "%s", name->value());
  703.       return NULL;
  704.    }
  705.  
  706.    return new(ctx) ir_call(callee, &parameters);
  707. }
  708.  
  709. static ir_expression *
  710. read_expression(_mesa_glsl_parse_state *st, s_list *list)
  711. {
  712.    void *ctx = st;
  713.    const unsigned list_length = list->length();
  714.    if (list_length < 4) {
  715.       ir_read_error(st, list, "expected (expression <type> <operator> "
  716.                               "<operand> [<operand>])");
  717.       return NULL;
  718.    }
  719.  
  720.    s_expression *type_expr = (s_expression*) list->subexpressions.head->next;
  721.    const glsl_type *type = read_type(st, type_expr);
  722.    if (type == NULL)
  723.       return NULL;
  724.  
  725.    /* Read the operator */
  726.    s_symbol *op_sym = SX_AS_SYMBOL(type_expr->next);
  727.    if (op_sym == NULL) {
  728.       ir_read_error(st, list, "expected operator, found non-symbol");
  729.       return NULL;
  730.    }
  731.  
  732.    ir_expression_operation op = ir_expression::get_operator(op_sym->value());
  733.    if (op == (ir_expression_operation) -1) {
  734.       ir_read_error(st, list, "invalid operator: %s", op_sym->value());
  735.       return NULL;
  736.    }
  737.    
  738.    /* Now that we know the operator, check for the right number of operands */
  739.    if (ir_expression::get_num_operands(op) == 2) {
  740.       if (list_length != 5) {
  741.          ir_read_error(st, list, "expected (expression <type> %s <operand> "
  742.                                  " <operand>)", op_sym->value());
  743.          return NULL;
  744.       }
  745.    } else {
  746.       if (list_length != 4) {
  747.          ir_read_error(st, list, "expected (expression <type> %s <operand>)",
  748.                        op_sym->value());
  749.          return NULL;
  750.       }
  751.    }
  752.  
  753.    s_expression *exp1 = (s_expression*) (op_sym->next);
  754.    ir_rvalue *arg1 = read_rvalue(st, exp1);
  755.    if (arg1 == NULL) {
  756.       ir_read_error(st, NULL, "when reading first operand of %s",
  757.                     op_sym->value());
  758.       return NULL;
  759.    }
  760.  
  761.    ir_rvalue *arg2 = NULL;
  762.    if (ir_expression::get_num_operands(op) == 2) {
  763.       s_expression *exp2 = (s_expression*) (exp1->next);
  764.       arg2 = read_rvalue(st, exp2);
  765.       if (arg2 == NULL) {
  766.          ir_read_error(st, NULL, "when reading second operand of %s",
  767.                        op_sym->value());
  768.          return NULL;
  769.       }
  770.    }
  771.  
  772.    return new(ctx) ir_expression(op, type, arg1, arg2);
  773. }
  774.  
  775. static ir_swizzle *
  776. read_swizzle(_mesa_glsl_parse_state *st, s_list *list)
  777. {
  778.    if (list->length() != 3) {
  779.       ir_read_error(st, list, "expected (swiz <swizzle> <rvalue>)");
  780.       return NULL;
  781.    }
  782.  
  783.    s_symbol *swiz = SX_AS_SYMBOL(list->subexpressions.head->next);
  784.    if (swiz == NULL) {
  785.       ir_read_error(st, list, "expected a valid swizzle; found non-symbol");
  786.       return NULL;
  787.    }
  788.  
  789.    if (strlen(swiz->value()) > 4) {
  790.       ir_read_error(st, list, "expected a valid swizzle; found %s",
  791.                     swiz->value());
  792.       return NULL;
  793.    }
  794.  
  795.    s_expression *sub = (s_expression*) swiz->next;
  796.    ir_rvalue *rvalue = read_rvalue(st, sub);
  797.    if (rvalue == NULL)
  798.       return NULL;
  799.  
  800.    ir_swizzle *ir = ir_swizzle::create(rvalue, swiz->value(),
  801.                                        rvalue->type->vector_elements);
  802.    if (ir == NULL)
  803.       ir_read_error(st, list, "invalid swizzle");
  804.  
  805.    return ir;
  806. }
  807.  
  808. static ir_constant *
  809. read_constant(_mesa_glsl_parse_state *st, s_list *list)
  810. {
  811.    void *ctx = st;
  812.    if (list->length() != 3) {
  813.       ir_read_error(st, list, "expected (constant <type> (...))");
  814.       return NULL;
  815.    }
  816.  
  817.    s_expression *type_expr = (s_expression*) list->subexpressions.head->next;
  818.    const glsl_type *type = read_type(st, type_expr);
  819.    if (type == NULL)
  820.       return NULL;
  821.  
  822.    s_list *values = SX_AS_LIST(type_expr->next);
  823.    if (values == NULL) {
  824.       ir_read_error(st, list, "expected (constant <type> (...))");
  825.       return NULL;
  826.    }
  827.  
  828.    if (type->is_array()) {
  829.       const unsigned elements_supplied = values->length();
  830.       if (elements_supplied != type->length) {
  831.          ir_read_error(st, values, "expected exactly %u array elements, "
  832.                        "given %u", type->length, elements_supplied);
  833.          return NULL;
  834.       }
  835.  
  836.       exec_list elements;
  837.       foreach_iter(exec_list_iterator, it, values->subexpressions) {
  838.          s_expression *expr = (s_expression *) it.get();
  839.          s_list *elt = SX_AS_LIST(expr);
  840.          if (elt == NULL) {
  841.             ir_read_error(st, expr, "expected (constant ...) array element");
  842.             return NULL;
  843.          }
  844.  
  845.          ir_constant *ir_elt = read_constant(st, elt);
  846.          if (ir_elt == NULL)
  847.             return NULL;
  848.          elements.push_tail(ir_elt);
  849.       }
  850.       return new(ctx) ir_constant(type, &elements);
  851.    }
  852.  
  853.    const glsl_type *const base_type = type->get_base_type();
  854.  
  855.    ir_constant_data data = { { 0 } };
  856.  
  857.    // Read in list of values (at most 16).
  858.    int k = 0;
  859.    foreach_iter(exec_list_iterator, it, values->subexpressions) {
  860.       if (k >= 16) {
  861.          ir_read_error(st, values, "expected at most 16 numbers");
  862.          return NULL;
  863.       }
  864.  
  865.       s_expression *expr = (s_expression*) it.get();
  866.  
  867.       if (base_type->base_type == GLSL_TYPE_FLOAT) {
  868.          s_number *value = SX_AS_NUMBER(expr);
  869.          if (value == NULL) {
  870.             ir_read_error(st, values, "expected numbers");
  871.             return NULL;
  872.          }
  873.          data.f[k] = value->fvalue();
  874.       } else {
  875.          s_int *value = SX_AS_INT(expr);
  876.          if (value == NULL) {
  877.             ir_read_error(st, values, "expected integers");
  878.             return NULL;
  879.          }
  880.  
  881.          switch (base_type->base_type) {
  882.          case GLSL_TYPE_UINT: {
  883.             data.u[k] = value->value();
  884.             break;
  885.          }
  886.          case GLSL_TYPE_INT: {
  887.             data.i[k] = value->value();
  888.             break;
  889.          }
  890.          case GLSL_TYPE_BOOL: {
  891.             data.b[k] = value->value();
  892.             break;
  893.          }
  894.          default:
  895.             ir_read_error(st, values, "unsupported constant type");
  896.             return NULL;
  897.          }
  898.       }
  899.       ++k;
  900.    }
  901.  
  902.    return new(ctx) ir_constant(type, &data);
  903. }
  904.  
  905. static ir_dereference *
  906. read_dereference(_mesa_glsl_parse_state *st, s_expression *expr)
  907. {
  908.    s_list *list = SX_AS_LIST(expr);
  909.    if (list == NULL || list->subexpressions.is_empty())
  910.       return NULL;
  911.  
  912.    s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.head);
  913.    assert(tag != NULL);
  914.  
  915.    if (strcmp(tag->value(), "var_ref") == 0)
  916.       return read_var_ref(st, list);
  917.    if (strcmp(tag->value(), "array_ref") == 0)
  918.       return read_array_ref(st, list);
  919.    if (strcmp(tag->value(), "record_ref") == 0)
  920.       return read_record_ref(st, list);
  921.    return NULL;
  922. }
  923.  
  924. static ir_dereference_variable *
  925. read_var_ref(_mesa_glsl_parse_state *st, s_list *list)
  926. {
  927.    void *ctx = st;
  928.    if (list->length() != 2) {
  929.       ir_read_error(st, list, "expected (var_ref <variable name>)");
  930.       return NULL;
  931.    }
  932.    s_symbol *var_name = SX_AS_SYMBOL(list->subexpressions.head->next);
  933.    if (var_name == NULL) {
  934.       ir_read_error(st, list, "expected (var_ref <variable name>)");
  935.       return NULL;
  936.    }
  937.  
  938.    ir_variable *var = st->symbols->get_variable(var_name->value());
  939.    if (var == NULL) {
  940.       ir_read_error(st, list, "undeclared variable: %s", var_name->value());
  941.       return NULL;
  942.    }
  943.  
  944.    return new(ctx) ir_dereference_variable(var);
  945. }
  946.  
  947. static ir_dereference_array *
  948. read_array_ref(_mesa_glsl_parse_state *st, s_list *list)
  949. {
  950.    void *ctx = st;
  951.    if (list->length() != 3) {
  952.       ir_read_error(st, list, "expected (array_ref <rvalue> <index>)");
  953.       return NULL;
  954.    }
  955.  
  956.    s_expression *subj_expr = (s_expression*) list->subexpressions.head->next;
  957.    ir_rvalue *subject = read_rvalue(st, subj_expr);
  958.    if (subject == NULL) {
  959.       ir_read_error(st, NULL, "when reading the subject of an array_ref");
  960.       return NULL;
  961.    }
  962.  
  963.    s_expression *idx_expr = (s_expression*) subj_expr->next;
  964.    ir_rvalue *idx = read_rvalue(st, idx_expr);
  965.    return new(ctx) ir_dereference_array(subject, idx);
  966. }
  967.  
  968. static ir_dereference_record *
  969. read_record_ref(_mesa_glsl_parse_state *st, s_list *list)
  970. {
  971.    void *ctx = st;
  972.    if (list->length() != 3) {
  973.       ir_read_error(st, list, "expected (record_ref <rvalue> <field>)");
  974.       return NULL;
  975.    }
  976.  
  977.    s_expression *subj_expr = (s_expression*) list->subexpressions.head->next;
  978.    ir_rvalue *subject = read_rvalue(st, subj_expr);
  979.    if (subject == NULL) {
  980.       ir_read_error(st, NULL, "when reading the subject of a record_ref");
  981.       return NULL;
  982.    }
  983.  
  984.    s_symbol *field = SX_AS_SYMBOL(subj_expr->next);
  985.    if (field == NULL) {
  986.       ir_read_error(st, list, "expected (record_ref ... <field name>)");
  987.       return NULL;
  988.    }
  989.    return new(ctx) ir_dereference_record(subject, field->value());
  990. }
  991.  
  992. static bool
  993. valid_texture_list_length(ir_texture_opcode op, s_list *list)
  994. {
  995.    unsigned required_length = 7;
  996.    if (op == ir_txf)
  997.       required_length = 5;
  998.    else if (op == ir_tex)
  999.       required_length = 6;
  1000.  
  1001.    return list->length() == required_length;
  1002. }
  1003.  
  1004. static ir_texture *
  1005. read_texture(_mesa_glsl_parse_state *st, s_list *list)
  1006. {
  1007.    void *ctx = st;
  1008.    s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.head);
  1009.    assert(tag != NULL);
  1010.  
  1011.    ir_texture_opcode op = ir_texture::get_opcode(tag->value());
  1012.    if (op == (ir_texture_opcode) -1)
  1013.       return NULL;
  1014.  
  1015.    if (!valid_texture_list_length(op, list)) {
  1016.       ir_read_error(st, NULL, "invalid list size in (%s ...)", tag->value());
  1017.       return NULL;
  1018.    }
  1019.  
  1020.    ir_texture *tex = new(ctx) ir_texture(op);
  1021.  
  1022.    // Read sampler (must be a deref)
  1023.    s_expression *sampler_expr = (s_expression *) tag->next;
  1024.    ir_dereference *sampler = read_dereference(st, sampler_expr);
  1025.    if (sampler == NULL) {
  1026.       ir_read_error(st, NULL, "when reading sampler in (%s ...)", tag->value());
  1027.       return NULL;
  1028.    }
  1029.    tex->set_sampler(sampler);
  1030.  
  1031.    // Read coordinate (any rvalue)
  1032.    s_expression *coordinate_expr = (s_expression *) sampler_expr->next;
  1033.    tex->coordinate = read_rvalue(st, coordinate_expr);
  1034.    if (tex->coordinate == NULL) {
  1035.       ir_read_error(st, NULL, "when reading coordinate in (%s ...)",
  1036.                     tag->value());
  1037.       return NULL;
  1038.    }
  1039.  
  1040.    // Read texel offset, i.e. (0 0 0)
  1041.    s_list *offset_list = SX_AS_LIST(coordinate_expr->next);
  1042.    if (offset_list == NULL || offset_list->length() != 3) {
  1043.       ir_read_error(st, offset_list, "expected (<int> <int> <int>)");
  1044.       return NULL;
  1045.    }
  1046.    s_int *offset_x = SX_AS_INT(offset_list->subexpressions.head);
  1047.    s_int *offset_y = SX_AS_INT(offset_list->subexpressions.head->next);
  1048.    s_int *offset_z = SX_AS_INT(offset_list->subexpressions.head->next->next);
  1049.    if (offset_x == NULL || offset_y == NULL || offset_z == NULL) {
  1050.       ir_read_error(st, offset_list, "expected (<int> <int> <int>)");
  1051.       return NULL;
  1052.    }
  1053.    tex->offsets[0] = offset_x->value();
  1054.    tex->offsets[1] = offset_y->value();
  1055.    tex->offsets[2] = offset_z->value();
  1056.  
  1057.    if (op == ir_txf) {
  1058.       s_expression *lod_expr = (s_expression *) offset_list->next;
  1059.       tex->lod_info.lod = read_rvalue(st, lod_expr);
  1060.       if (tex->lod_info.lod == NULL) {
  1061.          ir_read_error(st, NULL, "when reading LOD in (txf ...)");
  1062.          return NULL;
  1063.       }
  1064.    } else {
  1065.       s_expression *proj_expr = (s_expression *) offset_list->next;
  1066.       s_int *proj_as_int = SX_AS_INT(proj_expr);
  1067.       if (proj_as_int && proj_as_int->value() == 1) {
  1068.          tex->projector = NULL;
  1069.       } else {
  1070.          tex->projector = read_rvalue(st, proj_expr);
  1071.          if (tex->projector == NULL) {
  1072.             ir_read_error(st, NULL, "when reading projective divide in (%s ..)",
  1073.                           tag->value());
  1074.             return NULL;
  1075.          }
  1076.       }
  1077.  
  1078.       s_list *shadow_list = SX_AS_LIST(proj_expr->next);
  1079.       if (shadow_list == NULL) {
  1080.          ir_read_error(st, NULL, "shadow comparitor must be a list");
  1081.          return NULL;
  1082.       }
  1083.       if (shadow_list->subexpressions.is_empty()) {
  1084.          tex->shadow_comparitor= NULL;
  1085.       } else {
  1086.          tex->shadow_comparitor = read_rvalue(st, shadow_list);
  1087.          if (tex->shadow_comparitor == NULL) {
  1088.             ir_read_error(st, NULL, "when reading shadow comparitor in (%s ..)",
  1089.                           tag->value());
  1090.             return NULL;
  1091.          }
  1092.       }
  1093.       s_expression *lod_expr = (s_expression *) shadow_list->next;
  1094.  
  1095.       switch (op) {
  1096.       case ir_txb:
  1097.          tex->lod_info.bias = read_rvalue(st, lod_expr);
  1098.          if (tex->lod_info.bias == NULL) {
  1099.             ir_read_error(st, NULL, "when reading LOD bias in (txb ...)");
  1100.             return NULL;
  1101.          }
  1102.          break;
  1103.       case ir_txl:
  1104.          tex->lod_info.lod = read_rvalue(st, lod_expr);
  1105.          if (tex->lod_info.lod == NULL) {
  1106.             ir_read_error(st, NULL, "when reading LOD in (txl ...)");
  1107.             return NULL;
  1108.          }
  1109.          break;
  1110.       case ir_txd: {
  1111.          s_list *lod_list = SX_AS_LIST(lod_expr);
  1112.          if (lod_list->length() != 2) {
  1113.             ir_read_error(st, lod_expr, "expected (dPdx dPdy) in (txd ...)");
  1114.             return NULL;
  1115.          }
  1116.          s_expression *dx_expr = (s_expression *) lod_list->subexpressions.head;
  1117.          s_expression *dy_expr = (s_expression *) dx_expr->next;
  1118.  
  1119.          tex->lod_info.grad.dPdx = read_rvalue(st, dx_expr);
  1120.          if (tex->lod_info.grad.dPdx == NULL) {
  1121.             ir_read_error(st, NULL, "when reading dPdx in (txd ...)");
  1122.             return NULL;
  1123.          }
  1124.          tex->lod_info.grad.dPdy = read_rvalue(st, dy_expr);
  1125.          if (tex->lod_info.grad.dPdy == NULL) {
  1126.             ir_read_error(st, NULL, "when reading dPdy in (txd ...)");
  1127.             return NULL;
  1128.          }
  1129.          break;
  1130.       }
  1131.       default:
  1132.          // tex doesn't have any extra parameters and txf was handled earlier.
  1133.          break;
  1134.       };
  1135.    }
  1136.    return tex;
  1137. }
  1138.