summaryrefslogtreecommitdiff
path: root/src/compiler/glsl/ir_function.cpp
blob: 3ee0d170fb232cf615935f98cbce295c13bbae74 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
/*
 * Copyright © 2010 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include "compiler/glsl_types.h"
#include "ir.h"
#include "glsl_parser_extras.h"
#include "main/errors.h"

typedef enum {
   PARAMETER_LIST_NO_MATCH,
   PARAMETER_LIST_EXACT_MATCH,
   PARAMETER_LIST_INEXACT_MATCH /*< Match requires implicit conversion. */
} parameter_list_match_t;

/**
 * \brief Check if two parameter lists match.
 *
 * \param list_a Parameters of the function definition.
 * \param list_b Actual parameters passed to the function.
 * \see matching_signature()
 */
static parameter_list_match_t
parameter_lists_match(_mesa_glsl_parse_state *state,
                      const exec_list *list_a, const exec_list *list_b)
{
   const exec_node *node_a = list_a->get_head_raw();
   const exec_node *node_b = list_b->get_head_raw();

   /* This is set to true if there is an inexact match requiring an implicit
    * conversion. */
   bool inexact_match = false;

   for (/* empty */
	; !node_a->is_tail_sentinel()
	; node_a = node_a->next, node_b = node_b->next) {
      /* If all of the parameters from the other parameter list have been
       * exhausted, the lists have different length and, by definition,
       * do not match.
       */
      if (node_b->is_tail_sentinel())
	 return PARAMETER_LIST_NO_MATCH;


      const ir_variable *const param = (ir_variable *) node_a;
      const ir_rvalue *const actual = (ir_rvalue *) node_b;

      if (param->type == actual->type)
	 continue;

      /* Try to find an implicit conversion from actual to param. */
      inexact_match = true;
      switch ((enum ir_variable_mode)(param->data.mode)) {
      case ir_var_auto:
      case ir_var_uniform:
      case ir_var_shader_storage:
      case ir_var_temporary:
	 /* These are all error conditions.  It is invalid for a parameter to
	  * a function to be declared as auto (not in, out, or inout) or
	  * as uniform.
	  */
	 assert(0);
	 return PARAMETER_LIST_NO_MATCH;

      case ir_var_const_in:
      case ir_var_function_in:
	 if (!actual->type->can_implicitly_convert_to(param->type, state))
	    return PARAMETER_LIST_NO_MATCH;
	 break;

      case ir_var_function_out:
	 if (!param->type->can_implicitly_convert_to(actual->type, state))
	    return PARAMETER_LIST_NO_MATCH;
	 break;

      case ir_var_function_inout:
	 /* Since there are no bi-directional automatic conversions (e.g.,
	  * there is int -> float but no float -> int), inout parameters must
	  * be exact matches.
	  */
	 return PARAMETER_LIST_NO_MATCH;

      default:
	 assert(false);
	 return PARAMETER_LIST_NO_MATCH;
      }
   }

   /* If all of the parameters from the other parameter list have been
    * exhausted, the lists have different length and, by definition, do not
    * match.
    */
   if (!node_b->is_tail_sentinel())
      return PARAMETER_LIST_NO_MATCH;

   if (inexact_match)
      return PARAMETER_LIST_INEXACT_MATCH;
   else
      return PARAMETER_LIST_EXACT_MATCH;
}


/* Classes of parameter match, sorted (mostly) best matches first.
 * See is_better_parameter_match() below for the exceptions.
 * */
typedef enum {
   PARAMETER_EXACT_MATCH,
   PARAMETER_FLOAT_TO_DOUBLE,
   PARAMETER_INT_TO_FLOAT,
   PARAMETER_INT_TO_DOUBLE,
   PARAMETER_OTHER_CONVERSION,
} parameter_match_t;


static parameter_match_t
get_parameter_match_type(const ir_variable *param,
                         const ir_rvalue *actual)
{
   const glsl_type *from_type;
   const glsl_type *to_type;

   if (param->data.mode == ir_var_function_out) {
      from_type = param->type;
      to_type = actual->type;
   } else {
      from_type = actual->type;
      to_type = param->type;
   }

   if (from_type == to_type)
      return PARAMETER_EXACT_MATCH;

   if (to_type->is_double()) {
      if (from_type->is_float())
         return PARAMETER_FLOAT_TO_DOUBLE;
      return PARAMETER_INT_TO_DOUBLE;
   }

   if (to_type->is_float())
      return PARAMETER_INT_TO_FLOAT;

   /* int -> uint and any other oddball conversions */
   return PARAMETER_OTHER_CONVERSION;
}


static bool
is_better_parameter_match(parameter_match_t a_match,
                          parameter_match_t b_match)
{
   /* From section 6.1 of the GLSL 4.00 spec (and the ARB_gpu_shader5 spec):
    *
    * 1. An exact match is better than a match involving any implicit
    * conversion.
    *
    * 2. A match involving an implicit conversion from float to double
    * is better than match involving any other implicit conversion.
    *
    * [XXX: Not in GLSL 4.0: Only in ARB_gpu_shader5:
    * 3. A match involving an implicit conversion from either int or uint
    * to float is better than a match involving an implicit conversion
    * from either int or uint to double.]
    *
    * If none of the rules above apply to a particular pair of conversions,
    * neither conversion is considered better than the other.
    *
    * --
    *
    * Notably, the int->uint conversion is *not* considered to be better
    * or worse than int/uint->float or int/uint->double.
    */

   if (a_match >= PARAMETER_INT_TO_FLOAT && b_match == PARAMETER_OTHER_CONVERSION)
      return false;

   return a_match < b_match;
}


static bool
is_best_inexact_overload(const exec_list *actual_parameters,
                         ir_function_signature **matches,
                         int num_matches,
                         ir_function_signature *sig)
{
   /* From section 6.1 of the GLSL 4.00 spec (and the ARB_gpu_shader5 spec):
    *
    * "A function definition A is considered a better
    * match than function definition B if:
    *
    *   * for at least one function argument, the conversion for that argument
    *     in A is better than the corresponding conversion in B; and
    *
    *   * there is no function argument for which the conversion in B is better
    *     than the corresponding conversion in A.
    *
    * If a single function definition is considered a better match than every
    * other matching function definition, it will be used.  Otherwise, a
    * semantic error occurs and the shader will fail to compile."
    */
   for (ir_function_signature **other = matches;
        other < matches + num_matches; other++) {
      if (*other == sig)
         continue;

      const exec_node *node_a = sig->parameters.get_head_raw();
      const exec_node *node_b = (*other)->parameters.get_head_raw();
      const exec_node *node_p = actual_parameters->get_head_raw();

      bool better_for_some_parameter = false;

      for (/* empty */
           ; !node_a->is_tail_sentinel()
           ; node_a = node_a->next,
             node_b = node_b->next,
             node_p = node_p->next) {
         parameter_match_t a_match = get_parameter_match_type(
               (const ir_variable *)node_a,
               (const ir_rvalue *)node_p);
         parameter_match_t b_match = get_parameter_match_type(
               (const ir_variable *)node_b,
               (const ir_rvalue *)node_p);

         if (is_better_parameter_match(a_match, b_match))
               better_for_some_parameter = true;

         if (is_better_parameter_match(b_match, a_match))
               return false;     /* B is better for this parameter */
      }

      if (!better_for_some_parameter)
         return false;     /* A must be better than B for some parameter */

   }

   return true;
}


static ir_function_signature *
choose_best_inexact_overload(_mesa_glsl_parse_state *state,
                             const exec_list *actual_parameters,
                             ir_function_signature **matches,
                             int num_matches)
{
   if (num_matches == 0)
      return NULL;

   if (num_matches == 1)
      return *matches;

   /* Without GLSL 4.0, ARB_gpu_shader5, or MESA_shader_integer_functions,
    * there is no overload resolution among multiple inexact matches. Note
    * that state may be NULL here if called from the linker; in that case we
    * assume everything supported in any GLSL version is available.
    */
   if (!state || state->is_version(400, 0) || state->ARB_gpu_shader5_enable ||
       state->MESA_shader_integer_functions_enable) {
      for (ir_function_signature **sig = matches; sig < matches + num_matches; sig++) {
         if (is_best_inexact_overload(actual_parameters, matches, num_matches, *sig))
            return *sig;
      }
   }

   return NULL;   /* no best candidate */
}


ir_function_signature *
ir_function::matching_signature(_mesa_glsl_parse_state *state,
                                const exec_list *actual_parameters,
                                bool allow_builtins)
{
   bool is_exact;
   return matching_signature(state, actual_parameters, allow_builtins,
                             &is_exact);
}

ir_function_signature *
ir_function::matching_signature(_mesa_glsl_parse_state *state,
                                const exec_list *actual_parameters,
                                bool allow_builtins,
                                bool *is_exact)
{
   ir_function_signature **inexact_matches = NULL;
   ir_function_signature **inexact_matches_temp;
   ir_function_signature *match = NULL;
   int num_inexact_matches = 0;

   /* From page 42 (page 49 of the PDF) of the GLSL 1.20 spec:
    *
    * "If an exact match is found, the other signatures are ignored, and
    *  the exact match is used.  Otherwise, if no exact match is found, then
    *  the implicit conversions in Section 4.1.10 "Implicit Conversions" will
    *  be applied to the calling arguments if this can make their types match
    *  a signature.  In this case, it is a semantic error if there are
    *  multiple ways to apply these conversions to the actual arguments of a
    *  call such that the call can be made to match multiple signatures."
    */
   foreach_in_list(ir_function_signature, sig, &this->signatures) {
      /* Skip over any built-ins that aren't available in this shader. */
      if (sig->is_builtin() && (!allow_builtins ||
                                !sig->is_builtin_available(state)))
         continue;

      switch (parameter_lists_match(state, & sig->parameters, actual_parameters)) {
      case PARAMETER_LIST_EXACT_MATCH:
         *is_exact = true;
         free(inexact_matches);
         return sig;
      case PARAMETER_LIST_INEXACT_MATCH:
         inexact_matches_temp = (ir_function_signature **)
               realloc(inexact_matches,
                       sizeof(*inexact_matches) *
                       (num_inexact_matches + 1));
         if (inexact_matches_temp == NULL) {
            _mesa_error_no_memory(__func__);
            free(inexact_matches);
            return NULL;
         }
         inexact_matches = inexact_matches_temp;
         inexact_matches[num_inexact_matches++] = sig;
         continue;
      case PARAMETER_LIST_NO_MATCH:
	 continue;
      default:
	 assert(false);
	 return NULL;
      }
   }

   /* There is no exact match (we would have returned it by now).  If there
    * are multiple inexact matches, the call is ambiguous, which is an error.
    *
    * FINISHME: Report a decent error.  Returning NULL will likely result in
    * FINISHME: a "no matching signature" error; it should report that the
    * FINISHME: call is ambiguous.  But reporting errors from here is hard.
    */
   *is_exact = false;

   match = choose_best_inexact_overload(state, actual_parameters,
                                        inexact_matches, num_inexact_matches);

   free(inexact_matches);
   return match;
}


static bool
parameter_lists_match_exact(const exec_list *list_a, const exec_list *list_b)
{
   const exec_node *node_a = list_a->get_head_raw();
   const exec_node *node_b = list_b->get_head_raw();

   for (/* empty */
	; !node_a->is_tail_sentinel() && !node_b->is_tail_sentinel()
	; node_a = node_a->next, node_b = node_b->next) {
      ir_variable *a = (ir_variable *) node_a;
      ir_variable *b = (ir_variable *) node_b;

      /* If the types of the parameters do not match, the parameters lists
       * are different.
       */
      if (a->type != b->type)
         return false;
   }

   /* Unless both lists are exhausted, they differ in length and, by
    * definition, do not match.
    */
   return (node_a->is_tail_sentinel() == node_b->is_tail_sentinel());
}

ir_function_signature *
ir_function::exact_matching_signature(_mesa_glsl_parse_state *state,
                                      const exec_list *actual_parameters)
{
   foreach_in_list(ir_function_signature, sig, &this->signatures) {
      /* Skip over any built-ins that aren't available in this shader. */
      if (sig->is_builtin() && !sig->is_builtin_available(state))
         continue;

      if (parameter_lists_match_exact(&sig->parameters, actual_parameters))
	 return sig;
   }
   return NULL;
}