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
26extern "C" {
27#include <hieralloc.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
35const static bool debug = false;
36
37static void ir_read_error(_mesa_glsl_parse_state *, s_expression *,
38			  const char *fmt, ...);
39static const glsl_type *read_type(_mesa_glsl_parse_state *, s_expression *);
40
41static void scan_for_prototypes(_mesa_glsl_parse_state *, exec_list *,
42			        s_expression *);
43static ir_function *read_function(_mesa_glsl_parse_state *, s_list *,
44				  bool skip_body);
45static void read_function_sig(_mesa_glsl_parse_state *, ir_function *,
46			      s_list *, bool skip_body);
47
48static void read_instructions(_mesa_glsl_parse_state *, exec_list *,
49			      s_expression *, ir_loop *);
50static ir_instruction *read_instruction(_mesa_glsl_parse_state *,
51				        s_expression *, ir_loop *);
52static ir_variable *read_declaration(_mesa_glsl_parse_state *, s_list *);
53static ir_if *read_if(_mesa_glsl_parse_state *, s_list *, ir_loop *);
54static ir_loop *read_loop(_mesa_glsl_parse_state *st, s_list *list);
55static ir_return *read_return(_mesa_glsl_parse_state *, s_list *);
56
57static ir_rvalue *read_rvalue(_mesa_glsl_parse_state *, s_expression *);
58static ir_assignment *read_assignment(_mesa_glsl_parse_state *, s_list *);
59static ir_expression *read_expression(_mesa_glsl_parse_state *, s_list *);
60static ir_call *read_call(_mesa_glsl_parse_state *, s_list *);
61static ir_swizzle *read_swizzle(_mesa_glsl_parse_state *, s_list *);
62static ir_constant *read_constant(_mesa_glsl_parse_state *, s_list *);
63static ir_texture *read_texture(_mesa_glsl_parse_state *, s_list *);
64
65static ir_dereference *read_dereference(_mesa_glsl_parse_state *,
66				        s_expression *);
67static ir_dereference_variable *
68read_var_ref(_mesa_glsl_parse_state *, s_list *);
69static ir_dereference_array *
70read_array_ref(_mesa_glsl_parse_state *, s_list *);
71static ir_dereference_record *
72read_record_ref(_mesa_glsl_parse_state *, s_list *);
73
74void
75_mesa_glsl_read_ir(_mesa_glsl_parse_state *state, exec_list *instructions,
76		   const char *src, bool scan_for_protos)
77{
78   s_expression *expr = s_expression::read_expression(state, src);
79   if (expr == NULL) {
80      ir_read_error(state, NULL, "couldn't parse S-Expression.");
81      return;
82   }
83
84   if (scan_for_protos) {
85      scan_for_prototypes(state, instructions, expr);
86      if (state->error)
87	 return;
88   }
89
90   read_instructions(state, instructions, expr, NULL);
91   hieralloc_free(expr);
92
93   if (debug)
94      validate_ir_tree(instructions);
95}
96
97static void
98ir_read_error(_mesa_glsl_parse_state *state, s_expression *expr,
99	      const char *fmt, ...)
100{
101   va_list ap;
102
103   state->error = true;
104
105   if (state->current_function != NULL)
106      state->info_log = hieralloc_asprintf_append(state->info_log,
107			   "In function %s:\n",
108			   state->current_function->function_name());
109   state->info_log = hieralloc_strdup_append(state->info_log, "error: ");
110
111   va_start(ap, fmt);
112   state->info_log = hieralloc_vasprintf_append(state->info_log, fmt, ap);
113   va_end(ap);
114   state->info_log = hieralloc_strdup_append(state->info_log, "\n");
115
116   if (expr != NULL) {
117      state->info_log = hieralloc_strdup_append(state->info_log,
118					     "...in this context:\n   ");
119      expr->print();
120      state->info_log = hieralloc_strdup_append(state->info_log, "\n\n");
121   }
122}
123
124static const glsl_type *
125read_type(_mesa_glsl_parse_state *st, s_expression *expr)
126{
127   s_list *list = SX_AS_LIST(expr);
128   if (list != NULL) {
129      s_symbol *type_sym = SX_AS_SYMBOL(list->subexpressions.get_head());
130      if (type_sym == NULL) {
131	 ir_read_error(st, expr, "expected type (array ...) or (struct ...)");
132	 return NULL;
133      }
134      if (strcmp(type_sym->value(), "array") == 0) {
135	 if (list->length() != 3) {
136	    ir_read_error(st, expr, "expected type (array <type> <int>)");
137	    return NULL;
138	 }
139
140	 // Read base type
141	 s_expression *base_expr = (s_expression*) type_sym->next;
142	 const glsl_type *base_type = read_type(st, base_expr);
143	 if (base_type == NULL) {
144	    ir_read_error(st, NULL, "when reading base type of array");
145	    return NULL;
146	 }
147
148	 // Read array size
149	 s_int *size = SX_AS_INT(base_expr->next);
150	 if (size == NULL) {
151	    ir_read_error(st, expr, "found non-integer array size");
152	    return NULL;
153	 }
154
155	 return glsl_type::get_array_instance(base_type, size->value());
156      } else if (strcmp(type_sym->value(), "struct") == 0) {
157	 assert(false); // FINISHME
158      } else {
159	 ir_read_error(st, expr, "expected (array ...) or (struct ...); "
160				 "found (%s ...)", type_sym->value());
161	 return NULL;
162      }
163   }
164
165   s_symbol *type_sym = SX_AS_SYMBOL(expr);
166   if (type_sym == NULL) {
167      ir_read_error(st, expr, "expected <type> (symbol or list)");
168      return NULL;
169   }
170
171   const glsl_type *type = st->symbols->get_type(type_sym->value());
172   if (type == NULL)
173      ir_read_error(st, expr, "invalid type: %s", type_sym->value());
174
175   return type;
176}
177
178
179static void
180scan_for_prototypes(_mesa_glsl_parse_state *st, exec_list *instructions,
181		    s_expression *expr)
182{
183   s_list *list = SX_AS_LIST(expr);
184   if (list == NULL) {
185      ir_read_error(st, expr, "Expected (<instruction> ...); found an atom.");
186      return;
187   }
188
189   foreach_iter(exec_list_iterator, it, list->subexpressions) {
190      s_list *sub = SX_AS_LIST(it.get());
191      if (sub == NULL)
192	 continue; // not a (function ...); ignore it.
193
194      s_symbol *tag = SX_AS_SYMBOL(sub->subexpressions.get_head());
195      if (tag == NULL || strcmp(tag->value(), "function") != 0)
196	 continue; // not a (function ...); ignore it.
197
198      ir_function *f = read_function(st, sub, true);
199      if (f == NULL)
200	 return;
201      instructions->push_tail(f);
202   }
203}
204
205static ir_function *
206read_function(_mesa_glsl_parse_state *st, s_list *list, bool skip_body)
207{
208   void *ctx = st;
209   bool added = false;
210   if (list->length() < 3) {
211      ir_read_error(st, list, "Expected (function <name> (signature ...) ...)");
212      return NULL;
213   }
214
215   s_symbol *name = SX_AS_SYMBOL(list->subexpressions.head->next);
216   if (name == NULL) {
217      ir_read_error(st, list, "Expected (function <name> ...)");
218      return NULL;
219   }
220
221   ir_function *f = st->symbols->get_function(name->value());
222   if (f == NULL) {
223      f = new(ctx) ir_function(name->value());
224      added = st->symbols->add_function(f);
225      assert(added);
226   }
227
228   exec_list_iterator it = list->subexpressions.iterator();
229   it.next(); // skip "function" tag
230   it.next(); // skip function name
231   for (/* nothing */; it.has_next(); it.next()) {
232      s_list *siglist = SX_AS_LIST(it.get());
233      if (siglist == NULL) {
234	 ir_read_error(st, list, "Expected (function (signature ...) ...)");
235	 return NULL;
236      }
237
238      s_symbol *tag = SX_AS_SYMBOL(siglist->subexpressions.get_head());
239      if (tag == NULL || strcmp(tag->value(), "signature") != 0) {
240	 ir_read_error(st, siglist, "Expected (signature ...)");
241	 return NULL;
242      }
243
244      read_function_sig(st, f, siglist, skip_body);
245   }
246   return added ? f : NULL;
247}
248
249static void
250read_function_sig(_mesa_glsl_parse_state *st, ir_function *f, s_list *list,
251		  bool skip_body)
252{
253   void *ctx = st;
254   if (list->length() != 4) {
255      ir_read_error(st, list, "Expected (signature <type> (parameters ...) "
256			      "(<instruction> ...))");
257      return;
258   }
259
260   s_expression *type_expr = (s_expression*) list->subexpressions.head->next;
261   const glsl_type *return_type = read_type(st, type_expr);
262   if (return_type == NULL)
263      return;
264
265   s_list *paramlist = SX_AS_LIST(type_expr->next);
266   s_list *body_list = SX_AS_LIST(type_expr->next->next);
267   if (paramlist == NULL || body_list == NULL) {
268      ir_read_error(st, list, "Expected (signature <type> (parameters ...) "
269			      "(<instruction> ...))");
270      return;
271   }
272   s_symbol *paramtag = SX_AS_SYMBOL(paramlist->subexpressions.get_head());
273   if (paramtag == NULL || strcmp(paramtag->value(), "parameters") != 0) {
274      ir_read_error(st, paramlist, "Expected (parameters ...)");
275      return;
276   }
277
278   // Read the parameters list into a temporary place.
279   exec_list hir_parameters;
280   st->symbols->push_scope();
281
282   exec_list_iterator it = paramlist->subexpressions.iterator();
283   for (it.next() /* skip "parameters" */; it.has_next(); it.next()) {
284      s_list *decl = SX_AS_LIST(it.get());
285      ir_variable *var = read_declaration(st, decl);
286      if (var == NULL)
287	 return;
288
289      hir_parameters.push_tail(var);
290   }
291
292   ir_function_signature *sig = f->exact_matching_signature(&hir_parameters);
293   if (sig == NULL && skip_body) {
294      /* If scanning for prototypes, generate a new signature. */
295      sig = new(ctx) ir_function_signature(return_type);
296      sig->is_builtin = true;
297      f->add_signature(sig);
298   } else if (sig != NULL) {
299      const char *badvar = sig->qualifiers_match(&hir_parameters);
300      if (badvar != NULL) {
301	 ir_read_error(st, list, "function `%s' parameter `%s' qualifiers "
302		       "don't match prototype", f->name, badvar);
303	 return;
304      }
305
306      if (sig->return_type != return_type) {
307	 ir_read_error(st, list, "function `%s' return type doesn't "
308		       "match prototype", f->name);
309	 return;
310      }
311   } else {
312      /* No prototype for this body exists - skip it. */
313      st->symbols->pop_scope();
314      return;
315   }
316   assert(sig != NULL);
317
318   sig->replace_parameters(&hir_parameters);
319
320   if (!skip_body && !body_list->subexpressions.is_empty()) {
321      if (sig->is_defined) {
322	 ir_read_error(st, list, "function %s redefined", f->name);
323	 return;
324      }
325      st->current_function = sig;
326      read_instructions(st, &sig->body, body_list, NULL);
327      st->current_function = NULL;
328      sig->is_defined = true;
329   }
330
331   st->symbols->pop_scope();
332}
333
334static void
335read_instructions(_mesa_glsl_parse_state *st, exec_list *instructions,
336		  s_expression *expr, ir_loop *loop_ctx)
337{
338   // Read in a list of instructions
339   s_list *list = SX_AS_LIST(expr);
340   if (list == NULL) {
341      ir_read_error(st, expr, "Expected (<instruction> ...); found an atom.");
342      return;
343   }
344
345   foreach_iter(exec_list_iterator, it, list->subexpressions) {
346      s_expression *sub = (s_expression*) it.get();
347      ir_instruction *ir = read_instruction(st, sub, loop_ctx);
348      if (ir != NULL) {
349	 /* Global variable declarations should be moved to the top, before
350	  * any functions that might use them.  Functions are added to the
351	  * instruction stream when scanning for prototypes, so without this
352	  * hack, they always appear before variable declarations.
353	  */
354	 if (st->current_function == NULL && ir->as_variable() != NULL)
355	    instructions->push_head(ir);
356	 else
357	    instructions->push_tail(ir);
358      }
359   }
360}
361
362
363static ir_instruction *
364read_instruction(_mesa_glsl_parse_state *st, s_expression *expr,
365	         ir_loop *loop_ctx)
366{
367   void *ctx = st;
368   s_symbol *symbol = SX_AS_SYMBOL(expr);
369   if (symbol != NULL) {
370      if (strcmp(symbol->value(), "break") == 0 && loop_ctx != NULL)
371	 return new(ctx) ir_loop_jump(ir_loop_jump::jump_break);
372      if (strcmp(symbol->value(), "continue") == 0 && loop_ctx != NULL)
373	 return new(ctx) ir_loop_jump(ir_loop_jump::jump_continue);
374   }
375
376   s_list *list = SX_AS_LIST(expr);
377   if (list == NULL || list->subexpressions.is_empty()) {
378      ir_read_error(st, expr, "Invalid instruction.\n");
379      return NULL;
380   }
381
382   s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());
383   if (tag == NULL) {
384      ir_read_error(st, expr, "expected instruction tag");
385      return NULL;
386   }
387
388   ir_instruction *inst = NULL;
389   if (strcmp(tag->value(), "declare") == 0) {
390      inst = read_declaration(st, list);
391   } else if (strcmp(tag->value(), "assign") == 0) {
392      inst = read_assignment(st, list);
393   } else if (strcmp(tag->value(), "if") == 0) {
394      inst = read_if(st, list, loop_ctx);
395   } else if (strcmp(tag->value(), "loop") == 0) {
396      inst = read_loop(st, list);
397   } else if (strcmp(tag->value(), "return") == 0) {
398      inst = read_return(st, list);
399   } else if (strcmp(tag->value(), "function") == 0) {
400      inst = read_function(st, list, false);
401   } else {
402      inst = read_rvalue(st, list);
403      if (inst == NULL)
404	 ir_read_error(st, NULL, "when reading instruction");
405   }
406   return inst;
407}
408
409
410static ir_variable *
411read_declaration(_mesa_glsl_parse_state *st, s_list *list)
412{
413   void *ctx = st;
414   if (list->length() != 4) {
415      ir_read_error(st, list, "expected (declare (<qualifiers>) <type> "
416			      "<name>)");
417      return NULL;
418   }
419
420   s_list *quals = SX_AS_LIST(list->subexpressions.head->next);
421   if (quals == NULL) {
422      ir_read_error(st, list, "expected a list of variable qualifiers");
423      return NULL;
424   }
425
426   s_expression *type_expr = (s_expression*) quals->next;
427   const glsl_type *type = read_type(st, type_expr);
428   if (type == NULL)
429      return NULL;
430
431   s_symbol *var_name = SX_AS_SYMBOL(type_expr->next);
432   if (var_name == NULL) {
433      ir_read_error(st, list, "expected variable name, found non-symbol");
434      return NULL;
435   }
436
437   ir_variable *var = new(ctx) ir_variable(type, var_name->value(),
438					   ir_var_auto);
439
440   foreach_iter(exec_list_iterator, it, quals->subexpressions) {
441      s_symbol *qualifier = SX_AS_SYMBOL(it.get());
442      if (qualifier == NULL) {
443	 ir_read_error(st, list, "qualifier list must contain only symbols");
444	 delete var;
445	 return NULL;
446      }
447
448      // FINISHME: Check for duplicate/conflicting qualifiers.
449      if (strcmp(qualifier->value(), "centroid") == 0) {
450	 var->centroid = 1;
451      } else if (strcmp(qualifier->value(), "invariant") == 0) {
452	 var->invariant = 1;
453      } else if (strcmp(qualifier->value(), "uniform") == 0) {
454	 var->mode = ir_var_uniform;
455      } else if (strcmp(qualifier->value(), "auto") == 0) {
456	 var->mode = ir_var_auto;
457      } else if (strcmp(qualifier->value(), "in") == 0) {
458	 var->mode = ir_var_in;
459      } else if (strcmp(qualifier->value(), "out") == 0) {
460	 var->mode = ir_var_out;
461      } else if (strcmp(qualifier->value(), "inout") == 0) {
462	 var->mode = ir_var_inout;
463      } else if (strcmp(qualifier->value(), "smooth") == 0) {
464	 var->interpolation = ir_var_smooth;
465      } else if (strcmp(qualifier->value(), "flat") == 0) {
466	 var->interpolation = ir_var_flat;
467      } else if (strcmp(qualifier->value(), "noperspective") == 0) {
468	 var->interpolation = ir_var_noperspective;
469      } else {
470	 ir_read_error(st, list, "unknown qualifier: %s", qualifier->value());
471	 delete var;
472	 return NULL;
473      }
474   }
475
476   // Add the variable to the symbol table
477   st->symbols->add_variable(var);
478
479   return var;
480}
481
482
483static ir_if *
484read_if(_mesa_glsl_parse_state *st, s_list *list, ir_loop *loop_ctx)
485{
486   void *ctx = st;
487   if (list->length() != 4) {
488      ir_read_error(st, list, "expected (if <condition> (<then> ...) "
489                          "(<else> ...))");
490      return NULL;
491   }
492
493   s_expression *cond_expr = (s_expression*) list->subexpressions.head->next;
494   ir_rvalue *condition = read_rvalue(st, cond_expr);
495   if (condition == NULL) {
496      ir_read_error(st, NULL, "when reading condition of (if ...)");
497      return NULL;
498   }
499
500   s_expression *then_expr = (s_expression*) cond_expr->next;
501   s_expression *else_expr = (s_expression*) then_expr->next;
502
503   ir_if *iff = new(ctx) ir_if(condition);
504
505   read_instructions(st, &iff->then_instructions, then_expr, loop_ctx);
506   read_instructions(st, &iff->else_instructions, else_expr, loop_ctx);
507   if (st->error) {
508      delete iff;
509      iff = NULL;
510   }
511   return iff;
512}
513
514
515static ir_loop *
516read_loop(_mesa_glsl_parse_state *st, s_list *list)
517{
518   void *ctx = st;
519   if (list->length() != 6) {
520      ir_read_error(st, list, "expected (loop <counter> <from> <to> "
521			      "<increment> <body>)");
522      return NULL;
523   }
524
525   s_expression *count_expr = (s_expression*) list->subexpressions.head->next;
526   s_expression *from_expr  = (s_expression*) count_expr->next;
527   s_expression *to_expr    = (s_expression*) from_expr->next;
528   s_expression *inc_expr   = (s_expression*) to_expr->next;
529   s_expression *body_expr  = (s_expression*) inc_expr->next;
530
531   // FINISHME: actually read the count/from/to fields.
532
533   ir_loop *loop = new(ctx) ir_loop;
534   read_instructions(st, &loop->body_instructions, body_expr, loop);
535   if (st->error) {
536      delete loop;
537      loop = NULL;
538   }
539   return loop;
540}
541
542
543static ir_return *
544read_return(_mesa_glsl_parse_state *st, s_list *list)
545{
546   void *ctx = st;
547   if (list->length() != 2) {
548      ir_read_error(st, list, "expected (return <rvalue>)");
549      return NULL;
550   }
551
552   s_expression *expr = (s_expression*) list->subexpressions.head->next;
553
554   ir_rvalue *retval = read_rvalue(st, expr);
555   if (retval == NULL) {
556      ir_read_error(st, NULL, "when reading return value");
557      return NULL;
558   }
559
560   return new(ctx) ir_return(retval);
561}
562
563
564static ir_rvalue *
565read_rvalue(_mesa_glsl_parse_state *st, s_expression *expr)
566{
567   s_list *list = SX_AS_LIST(expr);
568   if (list == NULL || list->subexpressions.is_empty())
569      return NULL;
570
571   s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());
572   if (tag == NULL) {
573      ir_read_error(st, expr, "expected rvalue tag");
574      return NULL;
575   }
576
577   ir_rvalue *rvalue = read_dereference(st, list);
578   if (rvalue != NULL || st->error)
579      return rvalue;
580   else if (strcmp(tag->value(), "swiz") == 0) {
581      rvalue = read_swizzle(st, list);
582   } else if (strcmp(tag->value(), "expression") == 0) {
583      rvalue = read_expression(st, list);
584   } else if (strcmp(tag->value(), "call") == 0) {
585      rvalue = read_call(st, list);
586   } else if (strcmp(tag->value(), "constant") == 0) {
587      rvalue = read_constant(st, list);
588   } else {
589      rvalue = read_texture(st, list);
590      if (rvalue == NULL && !st->error)
591	 ir_read_error(st, expr, "unrecognized rvalue tag: %s", tag->value());
592   }
593
594   return rvalue;
595}
596
597static ir_assignment *
598read_assignment(_mesa_glsl_parse_state *st, s_list *list)
599{
600   void *ctx = st;
601   if (list->length() != 5) {
602      ir_read_error(st, list, "expected (assign <condition> (<write mask>) "
603			      "<lhs> <rhs>)");
604      return NULL;
605   }
606
607   s_expression *cond_expr = (s_expression*) list->subexpressions.head->next;
608   s_list       *mask_list = SX_AS_LIST(cond_expr->next);
609   s_expression *lhs_expr  = (s_expression*) cond_expr->next->next;
610   s_expression *rhs_expr  = (s_expression*) lhs_expr->next;
611
612   ir_rvalue *condition = read_rvalue(st, cond_expr);
613   if (condition == NULL) {
614      ir_read_error(st, NULL, "when reading condition of assignment");
615      return NULL;
616   }
617
618   if (mask_list == NULL || mask_list->length() > 1) {
619      ir_read_error(st, mask_list, "expected () or (<write mask>)");
620      return NULL;
621   }
622
623   unsigned mask = 0;
624   if (mask_list->length() == 1) {
625      s_symbol *mask_symbol = SX_AS_SYMBOL(mask_list->subexpressions.head);
626      if (mask_symbol == NULL) {
627	 ir_read_error(st, list, "expected a write mask; found non-symbol");
628	 return NULL;
629      }
630
631      const char *mask_str = mask_symbol->value();
632      unsigned mask_length = strlen(mask_str);
633      if (mask_length > 4) {
634	 ir_read_error(st, list, "invalid write mask: %s", mask_str);
635	 return NULL;
636      }
637
638      const unsigned idx_map[] = { 3, 0, 1, 2 }; /* w=bit 3, x=0, y=1, z=2 */
639
640      for (unsigned i = 0; i < mask_length; i++) {
641	 if (mask_str[i] < 'w' || mask_str[i] > 'z') {
642	    ir_read_error(st, list, "write mask contains invalid character: %c",
643			  mask_str[i]);
644	    return NULL;
645	 }
646	 mask |= 1 << idx_map[mask_str[i] - 'w'];
647      }
648   }
649
650   ir_dereference *lhs = read_dereference(st, lhs_expr);
651   if (lhs == NULL) {
652      ir_read_error(st, NULL, "when reading left-hand side of assignment");
653      return NULL;
654   }
655
656   ir_rvalue *rhs = read_rvalue(st, rhs_expr);
657   if (rhs == NULL) {
658      ir_read_error(st, NULL, "when reading right-hand side of assignment");
659      return NULL;
660   }
661
662   if (mask == 0 && (lhs->type->is_vector() || lhs->type->is_scalar())) {
663      ir_read_error(st, list, "non-zero write mask required.");
664      return NULL;
665   }
666
667   return new(ctx) ir_assignment(lhs, rhs, condition, mask);
668}
669
670static ir_call *
671read_call(_mesa_glsl_parse_state *st, s_list *list)
672{
673   void *ctx = st;
674   if (list->length() != 3) {
675      ir_read_error(st, list, "expected (call <name> (<param> ...))");
676      return NULL;
677   }
678
679   s_symbol *name = SX_AS_SYMBOL(list->subexpressions.head->next);
680   s_list *params = SX_AS_LIST(list->subexpressions.head->next->next);
681   if (name == NULL || params == NULL) {
682      ir_read_error(st, list, "expected (call <name> (<param> ...))");
683      return NULL;
684   }
685
686   exec_list parameters;
687
688   foreach_iter(exec_list_iterator, it, params->subexpressions) {
689      s_expression *expr = (s_expression*) it.get();
690      ir_rvalue *param = read_rvalue(st, expr);
691      if (param == NULL) {
692	 ir_read_error(st, list, "when reading parameter to function call");
693	 return NULL;
694      }
695      parameters.push_tail(param);
696   }
697
698   ir_function *f = st->symbols->get_function(name->value());
699   if (f == NULL) {
700      ir_read_error(st, list, "found call to undefined function %s",
701		    name->value());
702      return NULL;
703   }
704
705   ir_function_signature *callee = f->matching_signature(&parameters);
706   if (callee == NULL) {
707      ir_read_error(st, list, "couldn't find matching signature for function "
708                    "%s", name->value());
709      return NULL;
710   }
711
712   return new(ctx) ir_call(callee, &parameters);
713}
714
715static ir_expression *
716read_expression(_mesa_glsl_parse_state *st, s_list *list)
717{
718   void *ctx = st;
719   const unsigned list_length = list->length();
720   if (list_length < 4) {
721      ir_read_error(st, list, "expected (expression <type> <operator> "
722			      "<operand> [<operand>])");
723      return NULL;
724   }
725
726   s_expression *type_expr = (s_expression*) list->subexpressions.head->next;
727   const glsl_type *type = read_type(st, type_expr);
728   if (type == NULL)
729      return NULL;
730
731   /* Read the operator */
732   s_symbol *op_sym = SX_AS_SYMBOL(type_expr->next);
733   if (op_sym == NULL) {
734      ir_read_error(st, list, "expected operator, found non-symbol");
735      return NULL;
736   }
737
738   ir_expression_operation op = ir_expression::get_operator(op_sym->value());
739   if (op == (ir_expression_operation) -1) {
740      ir_read_error(st, list, "invalid operator: %s", op_sym->value());
741      return NULL;
742   }
743
744   /* Now that we know the operator, check for the right number of operands */
745   if (ir_expression::get_num_operands(op) == 2) {
746      if (list_length != 5) {
747	 ir_read_error(st, list, "expected (expression <type> %s <operand> "
748				 " <operand>)", op_sym->value());
749	 return NULL;
750      }
751   } else {
752      if (list_length != 4) {
753	 ir_read_error(st, list, "expected (expression <type> %s <operand>)",
754		       op_sym->value());
755	 return NULL;
756      }
757   }
758
759   s_expression *exp1 = (s_expression*) (op_sym->next);
760   ir_rvalue *arg1 = read_rvalue(st, exp1);
761   if (arg1 == NULL) {
762      ir_read_error(st, NULL, "when reading first operand of %s",
763		    op_sym->value());
764      return NULL;
765   }
766
767   ir_rvalue *arg2 = NULL;
768   if (ir_expression::get_num_operands(op) == 2) {
769      s_expression *exp2 = (s_expression*) (exp1->next);
770      arg2 = read_rvalue(st, exp2);
771      if (arg2 == NULL) {
772	 ir_read_error(st, NULL, "when reading second operand of %s",
773		       op_sym->value());
774	 return NULL;
775      }
776   }
777
778   return new(ctx) ir_expression(op, type, arg1, arg2);
779}
780
781static ir_swizzle *
782read_swizzle(_mesa_glsl_parse_state *st, s_list *list)
783{
784   if (list->length() != 3) {
785      ir_read_error(st, list, "expected (swiz <swizzle> <rvalue>)");
786      return NULL;
787   }
788
789   s_symbol *swiz = SX_AS_SYMBOL(list->subexpressions.head->next);
790   if (swiz == NULL) {
791      ir_read_error(st, list, "expected a valid swizzle; found non-symbol");
792      return NULL;
793   }
794
795   if (strlen(swiz->value()) > 4) {
796      ir_read_error(st, list, "expected a valid swizzle; found %s",
797		    swiz->value());
798      return NULL;
799   }
800
801   s_expression *sub = (s_expression*) swiz->next;
802   ir_rvalue *rvalue = read_rvalue(st, sub);
803   if (rvalue == NULL)
804      return NULL;
805
806   ir_swizzle *ir = ir_swizzle::create(rvalue, swiz->value(),
807				       rvalue->type->vector_elements);
808   if (ir == NULL)
809      ir_read_error(st, list, "invalid swizzle");
810
811   return ir;
812}
813
814static ir_constant *
815read_constant(_mesa_glsl_parse_state *st, s_list *list)
816{
817   void *ctx = st;
818   if (list->length() != 3) {
819      ir_read_error(st, list, "expected (constant <type> (...))");
820      return NULL;
821   }
822
823   s_expression *type_expr = (s_expression*) list->subexpressions.head->next;
824   const glsl_type *type = read_type(st, type_expr);
825   if (type == NULL)
826      return NULL;
827
828   s_list *values = SX_AS_LIST(type_expr->next);
829   if (values == NULL) {
830      ir_read_error(st, list, "expected (constant <type> (...))");
831      return NULL;
832   }
833
834   if (type->is_array()) {
835      const unsigned elements_supplied = values->length();
836      if (elements_supplied != type->length) {
837	 ir_read_error(st, values, "expected exactly %u array elements, "
838		       "given %u", type->length, elements_supplied);
839	 return NULL;
840      }
841
842      exec_list elements;
843      foreach_iter(exec_list_iterator, it, values->subexpressions) {
844	 s_expression *expr = (s_expression *) it.get();
845	 s_list *elt = SX_AS_LIST(expr);
846	 if (elt == NULL) {
847	    ir_read_error(st, expr, "expected (constant ...) array element");
848	    return NULL;
849	 }
850
851	 ir_constant *ir_elt = read_constant(st, elt);
852	 if (ir_elt == NULL)
853	    return NULL;
854	 elements.push_tail(ir_elt);
855      }
856      return new(ctx) ir_constant(type, &elements);
857   }
858
859   const glsl_type *const base_type = type->get_base_type();
860
861   ir_constant_data data = { { 0 } };
862
863   // Read in list of values (at most 16).
864   int k = 0;
865   foreach_iter(exec_list_iterator, it, values->subexpressions) {
866      if (k >= 16) {
867	 ir_read_error(st, values, "expected at most 16 numbers");
868	 return NULL;
869      }
870
871      s_expression *expr = (s_expression*) it.get();
872
873      if (base_type->base_type == GLSL_TYPE_FLOAT) {
874	 s_number *value = SX_AS_NUMBER(expr);
875	 if (value == NULL) {
876	    ir_read_error(st, values, "expected numbers");
877	    return NULL;
878	 }
879	 data.f[k] = value->fvalue();
880      } else {
881	 s_int *value = SX_AS_INT(expr);
882	 if (value == NULL) {
883	    ir_read_error(st, values, "expected integers");
884	    return NULL;
885	 }
886
887	 switch (base_type->base_type) {
888	 case GLSL_TYPE_UINT: {
889	    data.u[k] = value->value();
890	    break;
891	 }
892	 case GLSL_TYPE_INT: {
893	    data.i[k] = value->value();
894	    break;
895	 }
896	 case GLSL_TYPE_BOOL: {
897	    data.b[k] = value->value();
898	    break;
899	 }
900	 default:
901	    ir_read_error(st, values, "unsupported constant type");
902	    return NULL;
903	 }
904      }
905      ++k;
906   }
907
908   return new(ctx) ir_constant(type, &data);
909}
910
911static ir_dereference *
912read_dereference(_mesa_glsl_parse_state *st, s_expression *expr)
913{
914   s_list *list = SX_AS_LIST(expr);
915   if (list == NULL || list->subexpressions.is_empty())
916      return NULL;
917
918   s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.head);
919   assert(tag != NULL);
920
921   if (strcmp(tag->value(), "var_ref") == 0)
922      return read_var_ref(st, list);
923   if (strcmp(tag->value(), "array_ref") == 0)
924      return read_array_ref(st, list);
925   if (strcmp(tag->value(), "record_ref") == 0)
926      return read_record_ref(st, list);
927   return NULL;
928}
929
930static ir_dereference_variable *
931read_var_ref(_mesa_glsl_parse_state *st, s_list *list)
932{
933   void *ctx = st;
934   if (list->length() != 2) {
935      ir_read_error(st, list, "expected (var_ref <variable name>)");
936      return NULL;
937   }
938   s_symbol *var_name = SX_AS_SYMBOL(list->subexpressions.head->next);
939   if (var_name == NULL) {
940      ir_read_error(st, list, "expected (var_ref <variable name>)");
941      return NULL;
942   }
943
944   ir_variable *var = st->symbols->get_variable(var_name->value());
945   if (var == NULL) {
946      ir_read_error(st, list, "undeclared variable: %s", var_name->value());
947      return NULL;
948   }
949
950   return new(ctx) ir_dereference_variable(var);
951}
952
953static ir_dereference_array *
954read_array_ref(_mesa_glsl_parse_state *st, s_list *list)
955{
956   void *ctx = st;
957   if (list->length() != 3) {
958      ir_read_error(st, list, "expected (array_ref <rvalue> <index>)");
959      return NULL;
960   }
961
962   s_expression *subj_expr = (s_expression*) list->subexpressions.head->next;
963   ir_rvalue *subject = read_rvalue(st, subj_expr);
964   if (subject == NULL) {
965      ir_read_error(st, NULL, "when reading the subject of an array_ref");
966      return NULL;
967   }
968
969   s_expression *idx_expr = (s_expression*) subj_expr->next;
970   ir_rvalue *idx = read_rvalue(st, idx_expr);
971   return new(ctx) ir_dereference_array(subject, idx);
972}
973
974static ir_dereference_record *
975read_record_ref(_mesa_glsl_parse_state *st, s_list *list)
976{
977   void *ctx = st;
978   if (list->length() != 3) {
979      ir_read_error(st, list, "expected (record_ref <rvalue> <field>)");
980      return NULL;
981   }
982
983   s_expression *subj_expr = (s_expression*) list->subexpressions.head->next;
984   ir_rvalue *subject = read_rvalue(st, subj_expr);
985   if (subject == NULL) {
986      ir_read_error(st, NULL, "when reading the subject of a record_ref");
987      return NULL;
988   }
989
990   s_symbol *field = SX_AS_SYMBOL(subj_expr->next);
991   if (field == NULL) {
992      ir_read_error(st, list, "expected (record_ref ... <field name>)");
993      return NULL;
994   }
995   return new(ctx) ir_dereference_record(subject, field->value());
996}
997
998static bool
999valid_texture_list_length(ir_texture_opcode op, s_list *list)
1000{
1001   unsigned required_length = 7;
1002   if (op == ir_txf)
1003      required_length = 5;
1004   else if (op == ir_tex)
1005      required_length = 6;
1006
1007   return list->length() == required_length;
1008}
1009
1010static ir_texture *
1011read_texture(_mesa_glsl_parse_state *st, s_list *list)
1012{
1013   void *ctx = st;
1014   s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.head);
1015   assert(tag != NULL);
1016
1017   ir_texture_opcode op = ir_texture::get_opcode(tag->value());
1018   if (op == (ir_texture_opcode) -1)
1019      return NULL;
1020
1021   if (!valid_texture_list_length(op, list)) {
1022      ir_read_error(st, NULL, "invalid list size in (%s ...)", tag->value());
1023      return NULL;
1024   }
1025
1026   ir_texture *tex = new(ctx) ir_texture(op);
1027
1028   // Read sampler (must be a deref)
1029   s_expression *sampler_expr = (s_expression *) tag->next;
1030   ir_dereference *sampler = read_dereference(st, sampler_expr);
1031   if (sampler == NULL) {
1032      ir_read_error(st, NULL, "when reading sampler in (%s ...)", tag->value());
1033      return NULL;
1034   }
1035   tex->set_sampler(sampler);
1036
1037   // Read coordinate (any rvalue)
1038   s_expression *coordinate_expr = (s_expression *) sampler_expr->next;
1039   tex->coordinate = read_rvalue(st, coordinate_expr);
1040   if (tex->coordinate == NULL) {
1041      ir_read_error(st, NULL, "when reading coordinate in (%s ...)",
1042		    tag->value());
1043      return NULL;
1044   }
1045
1046   // Read texel offset, i.e. (0 0 0)
1047   s_list *offset_list = SX_AS_LIST(coordinate_expr->next);
1048   if (offset_list == NULL || offset_list->length() != 3) {
1049      ir_read_error(st, offset_list, "expected (<int> <int> <int>)");
1050      return NULL;
1051   }
1052   s_int *offset_x = SX_AS_INT(offset_list->subexpressions.head);
1053   s_int *offset_y = SX_AS_INT(offset_list->subexpressions.head->next);
1054   s_int *offset_z = SX_AS_INT(offset_list->subexpressions.head->next->next);
1055   if (offset_x == NULL || offset_y == NULL || offset_z == NULL) {
1056      ir_read_error(st, offset_list, "expected (<int> <int> <int>)");
1057      return NULL;
1058   }
1059   tex->offsets[0] = offset_x->value();
1060   tex->offsets[1] = offset_y->value();
1061   tex->offsets[2] = offset_z->value();
1062
1063   if (op == ir_txf) {
1064      s_expression *lod_expr = (s_expression *) offset_list->next;
1065      tex->lod_info.lod = read_rvalue(st, lod_expr);
1066      if (tex->lod_info.lod == NULL) {
1067	 ir_read_error(st, NULL, "when reading LOD in (txf ...)");
1068	 return NULL;
1069      }
1070   } else {
1071      s_expression *proj_expr = (s_expression *) offset_list->next;
1072      s_int *proj_as_int = SX_AS_INT(proj_expr);
1073      if (proj_as_int && proj_as_int->value() == 1) {
1074	 tex->projector = NULL;
1075      } else {
1076	 tex->projector = read_rvalue(st, proj_expr);
1077	 if (tex->projector == NULL) {
1078	    ir_read_error(st, NULL, "when reading projective divide in (%s ..)",
1079	                  tag->value());
1080	    return NULL;
1081	 }
1082      }
1083
1084      s_list *shadow_list = SX_AS_LIST(proj_expr->next);
1085      if (shadow_list == NULL) {
1086	 ir_read_error(st, NULL, "shadow comparitor must be a list");
1087	 return NULL;
1088      }
1089      if (shadow_list->subexpressions.is_empty()) {
1090	 tex->shadow_comparitor= NULL;
1091      } else {
1092	 tex->shadow_comparitor = read_rvalue(st, shadow_list);
1093	 if (tex->shadow_comparitor == NULL) {
1094	    ir_read_error(st, NULL, "when reading shadow comparitor in (%s ..)",
1095			  tag->value());
1096	    return NULL;
1097	 }
1098      }
1099      s_expression *lod_expr = (s_expression *) shadow_list->next;
1100
1101      switch (op) {
1102      case ir_txb:
1103	 tex->lod_info.bias = read_rvalue(st, lod_expr);
1104	 if (tex->lod_info.bias == NULL) {
1105	    ir_read_error(st, NULL, "when reading LOD bias in (txb ...)");
1106	    return NULL;
1107	 }
1108	 break;
1109      case ir_txl:
1110	 tex->lod_info.lod = read_rvalue(st, lod_expr);
1111	 if (tex->lod_info.lod == NULL) {
1112	    ir_read_error(st, NULL, "when reading LOD in (txl ...)");
1113	    return NULL;
1114	 }
1115	 break;
1116      case ir_txd: {
1117	 s_list *lod_list = SX_AS_LIST(lod_expr);
1118	 if (lod_list->length() != 2) {
1119	    ir_read_error(st, lod_expr, "expected (dPdx dPdy) in (txd ...)");
1120	    return NULL;
1121	 }
1122	 s_expression *dx_expr = (s_expression *) lod_list->subexpressions.head;
1123	 s_expression *dy_expr = (s_expression *) dx_expr->next;
1124
1125	 tex->lod_info.grad.dPdx = read_rvalue(st, dx_expr);
1126	 if (tex->lod_info.grad.dPdx == NULL) {
1127	    ir_read_error(st, NULL, "when reading dPdx in (txd ...)");
1128	    return NULL;
1129	 }
1130	 tex->lod_info.grad.dPdy = read_rvalue(st, dy_expr);
1131	 if (tex->lod_info.grad.dPdy == NULL) {
1132	    ir_read_error(st, NULL, "when reading dPdy in (txd ...)");
1133	    return NULL;
1134	 }
1135	 break;
1136      }
1137      default:
1138	 // tex doesn't have any extra parameters and txf was handled earlier.
1139	 break;
1140      };
1141   }
1142   return tex;
1143}
1144