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ea900239 | 1 | /* Type based alias analysis. |
fa10beec RW |
2 | Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, |
3 | Inc. | |
ea900239 DB |
4 | Contributed by Kenneth Zadeck <zadeck@naturalbridge.com> |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify it under | |
9 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 10 | Software Foundation; either version 3, or (at your option) any later |
ea900239 DB |
11 | version. |
12 | ||
13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
ea900239 DB |
21 | |
22 | /* This pass determines which types in the program contain only | |
23 | instances that are completely encapsulated by the compilation unit. | |
24 | Those types that are encapsulated must also pass the further | |
25 | requirement that there be no bad operations on any instances of | |
26 | those types. | |
27 | ||
28 | A great deal of freedom in compilation is allowed for the instances | |
29 | of those types that pass these conditions. | |
30 | */ | |
31 | ||
32 | /* The code in this module is called by the ipa pass manager. It | |
33 | should be one of the later passes since its information is used by | |
34 | the rest of the compilation. */ | |
35 | ||
36 | #include "config.h" | |
37 | #include "system.h" | |
38 | #include "coretypes.h" | |
39 | #include "tm.h" | |
40 | #include "tree.h" | |
41 | #include "tree-flow.h" | |
42 | #include "tree-inline.h" | |
43 | #include "tree-pass.h" | |
44 | #include "langhooks.h" | |
45 | #include "pointer-set.h" | |
ea264ca5 | 46 | #include "splay-tree.h" |
ea900239 DB |
47 | #include "ggc.h" |
48 | #include "ipa-utils.h" | |
49 | #include "ipa-type-escape.h" | |
726a989a | 50 | #include "gimple.h" |
ea900239 DB |
51 | #include "cgraph.h" |
52 | #include "output.h" | |
53 | #include "flags.h" | |
54 | #include "timevar.h" | |
55 | #include "diagnostic.h" | |
56 | #include "langhooks.h" | |
57 | ||
58 | /* Some of the aliasing is called very early, before this phase is | |
59 | called. To assure that this is not a problem, we keep track of if | |
60 | this phase has been run. */ | |
61 | static bool initialized = false; | |
62 | ||
ea900239 DB |
63 | /* Scratch bitmap for avoiding work. */ |
64 | static bitmap been_there_done_that; | |
65 | static bitmap bitmap_tmp; | |
66 | ||
67 | /* There are two levels of escape that types can undergo. | |
68 | ||
69 | EXPOSED_PARAMETER - some instance of the variable is | |
70 | passed by value into an externally visible function or some | |
71 | instance of the variable is passed out of an externally visible | |
72 | function as a return value. In this case any of the fields of the | |
73 | variable that are pointer types end up having their types marked as | |
74 | FULL_ESCAPE. | |
75 | ||
76 | FULL_ESCAPE - when bad things happen to good types. One of the | |
77 | following things happens to the type: (a) either an instance of the | |
78 | variable has its address passed to an externally visible function, | |
79 | (b) the address is taken and some bad cast happens to the address | |
80 | or (c) explicit arithmetic is done to the address. | |
81 | */ | |
82 | ||
83 | enum escape_t | |
84 | { | |
85 | EXPOSED_PARAMETER, | |
86 | FULL_ESCAPE | |
87 | }; | |
88 | ||
89 | /* The following two bit vectors global_types_* correspond to | |
90 | previous cases above. During the analysis phase, a bit is set in | |
91 | one of these vectors if an operation of the offending class is | |
92 | discovered to happen on the associated type. */ | |
93 | ||
94 | static bitmap global_types_exposed_parameter; | |
95 | static bitmap global_types_full_escape; | |
96 | ||
97 | /* All of the types seen in this compilation unit. */ | |
98 | static bitmap global_types_seen; | |
99 | /* Reverse map to take a canon uid and map it to a canon type. Uid's | |
100 | are never manipulated unless they are associated with a canon | |
101 | type. */ | |
102 | static splay_tree uid_to_canon_type; | |
103 | ||
104 | /* Internal structure of type mapping code. This maps a canon type | |
105 | name to its canon type. */ | |
106 | static splay_tree all_canon_types; | |
107 | ||
108 | /* Map from type clones to the single canon type. */ | |
109 | static splay_tree type_to_canon_type; | |
110 | ||
111 | /* A splay tree of bitmaps. An element X in the splay tree has a bit | |
112 | set in its bitmap at TYPE_UID (TYPE_MAIN_VARIANT (Y)) if there was | |
113 | an operation in the program of the form "&X.Y". */ | |
114 | static splay_tree uid_to_addressof_down_map; | |
115 | ||
116 | /* A splay tree of bitmaps. An element Y in the splay tree has a bit | |
117 | set in its bitmap at TYPE_UID (TYPE_MAIN_VARIANT (X)) if there was | |
118 | an operation in the program of the form "&X.Y". */ | |
119 | static splay_tree uid_to_addressof_up_map; | |
120 | ||
121 | /* Tree to hold the subtype maps used to mark subtypes of escaped | |
122 | types. */ | |
123 | static splay_tree uid_to_subtype_map; | |
124 | ||
125 | /* Records tree nodes seen in cgraph_create_edges. Simply using | |
126 | walk_tree_without_duplicates doesn't guarantee each node is visited | |
127 | once because it gets a new htab upon each recursive call from | |
128 | scan_for_refs. */ | |
129 | static struct pointer_set_t *visited_nodes; | |
130 | ||
d4e70294 OG |
131 | /* Visited stmts by walk_use_def_chains function because it's called |
132 | recursively. */ | |
133 | static struct pointer_set_t *visited_stmts; | |
134 | ||
ea900239 DB |
135 | static bitmap_obstack ipa_obstack; |
136 | ||
d4e70294 OG |
137 | /* Static functions from this file that are used |
138 | before being defined. */ | |
726a989a RB |
139 | static unsigned int look_for_casts (tree); |
140 | static bool is_cast_from_non_pointer (tree, gimple, void *); | |
d4e70294 | 141 | |
ea900239 | 142 | /* Get the name of TYPE or return the string "<UNNAMED>". */ |
741ac903 | 143 | static const char* |
ea900239 DB |
144 | get_name_of_type (tree type) |
145 | { | |
146 | tree name = TYPE_NAME (type); | |
147 | ||
148 | if (!name) | |
149 | /* Unnamed type, do what you like here. */ | |
741ac903 | 150 | return "<UNNAMED>"; |
ea900239 DB |
151 | |
152 | /* It will be a TYPE_DECL in the case of a typedef, otherwise, an | |
153 | identifier_node */ | |
154 | if (TREE_CODE (name) == TYPE_DECL) | |
155 | { | |
156 | /* Each DECL has a DECL_NAME field which contains an | |
157 | IDENTIFIER_NODE. (Some decls, most often labels, may have | |
158 | zero as the DECL_NAME). */ | |
159 | if (DECL_NAME (name)) | |
741ac903 | 160 | return IDENTIFIER_POINTER (DECL_NAME (name)); |
ea900239 DB |
161 | else |
162 | /* Unnamed type, do what you like here. */ | |
741ac903 | 163 | return "<UNNAMED>"; |
ea900239 DB |
164 | } |
165 | else if (TREE_CODE (name) == IDENTIFIER_NODE) | |
741ac903 | 166 | return IDENTIFIER_POINTER (name); |
ea900239 | 167 | else |
741ac903 | 168 | return "<UNNAMED>"; |
ea900239 DB |
169 | } |
170 | ||
171 | struct type_brand_s | |
172 | { | |
741ac903 | 173 | const char* name; |
ea900239 DB |
174 | int seq; |
175 | }; | |
176 | ||
177 | /* Splay tree comparison function on type_brand_s structures. */ | |
178 | ||
179 | static int | |
180 | compare_type_brand (splay_tree_key sk1, splay_tree_key sk2) | |
181 | { | |
182 | struct type_brand_s * k1 = (struct type_brand_s *) sk1; | |
183 | struct type_brand_s * k2 = (struct type_brand_s *) sk2; | |
184 | ||
185 | int value = strcmp(k1->name, k2->name); | |
186 | if (value == 0) | |
187 | return k2->seq - k1->seq; | |
188 | else | |
189 | return value; | |
190 | } | |
191 | ||
192 | /* All of the "unique_type" code is a hack to get around the sleazy | |
193 | implementation used to compile more than file. Currently gcc does | |
194 | not get rid of multiple instances of the same type that have been | |
195 | collected from different compilation units. */ | |
196 | /* This is a trivial algorithm for removing duplicate types. This | |
197 | would not work for any language that used structural equivalence as | |
198 | the basis of its type system. */ | |
40790141 MS |
199 | /* Return TYPE if no type compatible with TYPE has been seen so far, |
200 | otherwise return a type compatible with TYPE that has already been | |
201 | processed. */ | |
ea900239 DB |
202 | |
203 | static tree | |
204 | discover_unique_type (tree type) | |
205 | { | |
5ed6ace5 | 206 | struct type_brand_s * brand = XNEW (struct type_brand_s); |
ea900239 DB |
207 | int i = 0; |
208 | splay_tree_node result; | |
2eca7d15 RH |
209 | |
210 | brand->name = get_name_of_type (type); | |
211 | ||
ea900239 | 212 | while (1) |
2eca7d15 RH |
213 | { |
214 | brand->seq = i++; | |
215 | result = splay_tree_lookup (all_canon_types, (splay_tree_key) brand); | |
216 | ||
217 | if (result) | |
218 | { | |
219 | /* Create an alias since this is just the same as | |
220 | other_type. */ | |
221 | tree other_type = (tree) result->value; | |
f4088621 | 222 | if (types_compatible_p (type, other_type)) |
2eca7d15 RH |
223 | { |
224 | free (brand); | |
225 | /* Insert this new type as an alias for other_type. */ | |
226 | splay_tree_insert (type_to_canon_type, | |
227 | (splay_tree_key) type, | |
228 | (splay_tree_value) other_type); | |
229 | return other_type; | |
230 | } | |
231 | /* Not compatible, look for next instance with same name. */ | |
232 | } | |
233 | else | |
234 | { | |
235 | /* No more instances, create new one since this is the first | |
236 | time we saw this type. */ | |
237 | brand->seq = i++; | |
238 | /* Insert the new brand. */ | |
239 | splay_tree_insert (all_canon_types, | |
240 | (splay_tree_key) brand, | |
241 | (splay_tree_value) type); | |
242 | ||
243 | /* Insert this new type as an alias for itself. */ | |
244 | splay_tree_insert (type_to_canon_type, | |
245 | (splay_tree_key) type, | |
246 | (splay_tree_value) type); | |
247 | ||
248 | /* Insert the uid for reverse lookup; */ | |
249 | splay_tree_insert (uid_to_canon_type, | |
250 | (splay_tree_key) TYPE_UID (type), | |
251 | (splay_tree_value) type); | |
252 | ||
253 | bitmap_set_bit (global_types_seen, TYPE_UID (type)); | |
254 | return type; | |
255 | } | |
256 | } | |
ea900239 DB |
257 | } |
258 | ||
259 | /* Return true if TYPE is one of the type classes that we are willing | |
260 | to analyze. This skips the goofy types like arrays of pointers to | |
261 | methods. */ | |
262 | static bool | |
263 | type_to_consider (tree type) | |
264 | { | |
265 | /* Strip the *'s off. */ | |
266 | type = TYPE_MAIN_VARIANT (type); | |
267 | while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE) | |
268 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
269 | ||
270 | switch (TREE_CODE (type)) | |
271 | { | |
272 | case BOOLEAN_TYPE: | |
ea900239 DB |
273 | case COMPLEX_TYPE: |
274 | case ENUMERAL_TYPE: | |
275 | case INTEGER_TYPE: | |
276 | case QUAL_UNION_TYPE: | |
277 | case REAL_TYPE: | |
325217ed | 278 | case FIXED_POINT_TYPE: |
ea900239 DB |
279 | case RECORD_TYPE: |
280 | case UNION_TYPE: | |
281 | case VECTOR_TYPE: | |
282 | case VOID_TYPE: | |
283 | return true; | |
284 | ||
285 | default: | |
286 | return false; | |
287 | } | |
288 | } | |
289 | ||
290 | /* Get the canon type of TYPE. If SEE_THRU_PTRS is true, remove all | |
291 | the POINTER_TOs and if SEE_THRU_ARRAYS is true, remove all of the | |
292 | ARRAY_OFs and POINTER_TOs. */ | |
293 | ||
294 | static tree | |
295 | get_canon_type (tree type, bool see_thru_ptrs, bool see_thru_arrays) | |
296 | { | |
297 | splay_tree_node result; | |
298 | /* Strip the *'s off. */ | |
299 | if (!type || !type_to_consider (type)) | |
300 | return NULL; | |
301 | ||
302 | type = TYPE_MAIN_VARIANT (type); | |
303 | if (see_thru_arrays) | |
304 | while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE) | |
305 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
306 | ||
307 | else if (see_thru_ptrs) | |
308 | while (POINTER_TYPE_P (type)) | |
309 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
310 | ||
726a989a | 311 | result = splay_tree_lookup (type_to_canon_type, (splay_tree_key) type); |
ea900239 DB |
312 | |
313 | if (result == NULL) | |
314 | return discover_unique_type (type); | |
315 | else return (tree) result->value; | |
316 | } | |
317 | ||
318 | /* Same as GET_CANON_TYPE, except return the TYPE_ID rather than the | |
319 | TYPE. */ | |
320 | ||
321 | static int | |
322 | get_canon_type_uid (tree type, bool see_thru_ptrs, bool see_thru_arrays) | |
323 | { | |
324 | type = get_canon_type (type, see_thru_ptrs, see_thru_arrays); | |
325 | if (type) | |
326 | return TYPE_UID(type); | |
327 | else return 0; | |
328 | } | |
329 | ||
330 | /* Return 0 if TYPE is a record or union type. Return a positive | |
331 | number if TYPE is a pointer to a record or union. The number is | |
332 | the number of pointer types stripped to get to the record or union | |
333 | type. Return -1 if TYPE is none of the above. */ | |
334 | ||
335 | int | |
336 | ipa_type_escape_star_count_of_interesting_type (tree type) | |
337 | { | |
338 | int count = 0; | |
339 | /* Strip the *'s off. */ | |
340 | if (!type) | |
341 | return -1; | |
342 | type = TYPE_MAIN_VARIANT (type); | |
343 | while (POINTER_TYPE_P (type)) | |
344 | { | |
345 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
346 | count++; | |
347 | } | |
348 | ||
349 | /* We are interested in records, and unions only. */ | |
350 | if (TREE_CODE (type) == RECORD_TYPE | |
351 | || TREE_CODE (type) == QUAL_UNION_TYPE | |
352 | || TREE_CODE (type) == UNION_TYPE) | |
353 | return count; | |
354 | else | |
355 | return -1; | |
356 | } | |
357 | ||
358 | ||
359 | /* Return 0 if TYPE is a record or union type. Return a positive | |
360 | number if TYPE is a pointer to a record or union. The number is | |
361 | the number of pointer types stripped to get to the record or union | |
362 | type. Return -1 if TYPE is none of the above. */ | |
363 | ||
364 | int | |
365 | ipa_type_escape_star_count_of_interesting_or_array_type (tree type) | |
366 | { | |
367 | int count = 0; | |
368 | /* Strip the *'s off. */ | |
369 | if (!type) | |
370 | return -1; | |
371 | type = TYPE_MAIN_VARIANT (type); | |
372 | while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE) | |
373 | { | |
374 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
375 | count++; | |
376 | } | |
377 | ||
378 | /* We are interested in records, and unions only. */ | |
379 | if (TREE_CODE (type) == RECORD_TYPE | |
380 | || TREE_CODE (type) == QUAL_UNION_TYPE | |
381 | || TREE_CODE (type) == UNION_TYPE) | |
382 | return count; | |
383 | else | |
384 | return -1; | |
385 | } | |
386 | ||
387 | ||
388 | /* Return true if the record, or union TYPE passed in escapes this | |
389 | compilation unit. Note that all of the pointer-to's are removed | |
390 | before testing since these may not be correct. */ | |
391 | ||
392 | bool | |
393 | ipa_type_escape_type_contained_p (tree type) | |
394 | { | |
395 | if (!initialized) | |
396 | return false; | |
397 | return !bitmap_bit_p (global_types_full_escape, | |
398 | get_canon_type_uid (type, true, false)); | |
399 | } | |
400 | ||
643519b7 | 401 | /* Return true if a modification to a field of type FIELD_TYPE cannot |
ea900239 DB |
402 | clobber a record of RECORD_TYPE. */ |
403 | ||
404 | bool | |
405 | ipa_type_escape_field_does_not_clobber_p (tree record_type, tree field_type) | |
406 | { | |
407 | splay_tree_node result; | |
408 | int uid; | |
409 | ||
410 | if (!initialized) | |
411 | return false; | |
412 | ||
413 | /* Strip off all of the pointer tos on the record type. Strip the | |
414 | same number of pointer tos from the field type. If the field | |
415 | type has fewer, it could not have been aliased. */ | |
416 | record_type = TYPE_MAIN_VARIANT (record_type); | |
417 | field_type = TYPE_MAIN_VARIANT (field_type); | |
418 | while (POINTER_TYPE_P (record_type)) | |
419 | { | |
420 | record_type = TYPE_MAIN_VARIANT (TREE_TYPE (record_type)); | |
421 | if (POINTER_TYPE_P (field_type)) | |
422 | field_type = TYPE_MAIN_VARIANT (TREE_TYPE (field_type)); | |
423 | else | |
424 | /* However, if field_type is a union, this quick test is not | |
425 | correct since one of the variants of the union may be a | |
426 | pointer to type and we cannot see across that here. So we | |
427 | just strip the remaining pointer tos off the record type | |
428 | and fall thru to the more precise code. */ | |
429 | if (TREE_CODE (field_type) == QUAL_UNION_TYPE | |
430 | || TREE_CODE (field_type) == UNION_TYPE) | |
431 | { | |
432 | while (POINTER_TYPE_P (record_type)) | |
433 | record_type = TYPE_MAIN_VARIANT (TREE_TYPE (record_type)); | |
434 | break; | |
435 | } | |
436 | else | |
437 | return true; | |
438 | } | |
439 | ||
440 | record_type = get_canon_type (record_type, true, true); | |
441 | /* The record type must be contained. The field type may | |
442 | escape. */ | |
443 | if (!ipa_type_escape_type_contained_p (record_type)) | |
444 | return false; | |
445 | ||
446 | uid = TYPE_UID (record_type); | |
447 | result = splay_tree_lookup (uid_to_addressof_down_map, (splay_tree_key) uid); | |
448 | ||
449 | if (result) | |
450 | { | |
451 | bitmap field_type_map = (bitmap) result->value; | |
452 | uid = get_canon_type_uid (field_type, true, true); | |
453 | /* If the bit is there, the address was taken. If not, it | |
454 | wasn't. */ | |
455 | return !bitmap_bit_p (field_type_map, uid); | |
456 | } | |
457 | else | |
458 | /* No bitmap means no addresses were taken. */ | |
459 | return true; | |
460 | } | |
461 | ||
462 | ||
463 | /* Add TYPE to the suspect type set. Return true if the bit needed to | |
464 | be marked. */ | |
465 | ||
466 | static tree | |
467 | mark_type (tree type, enum escape_t escape_status) | |
468 | { | |
469 | bitmap map = NULL; | |
470 | int uid; | |
471 | ||
472 | type = get_canon_type (type, true, true); | |
473 | if (!type) | |
474 | return NULL; | |
475 | ||
476 | switch (escape_status) | |
477 | { | |
478 | case EXPOSED_PARAMETER: | |
479 | map = global_types_exposed_parameter; | |
480 | break; | |
481 | case FULL_ESCAPE: | |
482 | map = global_types_full_escape; | |
483 | break; | |
484 | } | |
485 | ||
486 | uid = TYPE_UID (type); | |
487 | if (bitmap_bit_p (map, uid)) | |
488 | return type; | |
489 | else | |
490 | { | |
491 | bitmap_set_bit (map, uid); | |
492 | if (escape_status == FULL_ESCAPE) | |
493 | { | |
a4174ebf | 494 | /* Efficiency hack. When things are bad, do not mess around |
ea900239 DB |
495 | with this type anymore. */ |
496 | bitmap_set_bit (global_types_exposed_parameter, uid); | |
497 | } | |
498 | } | |
499 | return type; | |
500 | } | |
501 | ||
502 | /* Add interesting TYPE to the suspect type set. If the set is | |
503 | EXPOSED_PARAMETER and the TYPE is a pointer type, the set is | |
504 | changed to FULL_ESCAPE. */ | |
505 | ||
506 | static void | |
507 | mark_interesting_type (tree type, enum escape_t escape_status) | |
508 | { | |
509 | if (!type) return; | |
510 | if (ipa_type_escape_star_count_of_interesting_type (type) >= 0) | |
511 | { | |
512 | if ((escape_status == EXPOSED_PARAMETER) | |
513 | && POINTER_TYPE_P (type)) | |
514 | /* EXPOSED_PARAMETERs are only structs or unions are passed by | |
515 | value. Anything passed by reference to an external | |
516 | function fully exposes the type. */ | |
517 | mark_type (type, FULL_ESCAPE); | |
518 | else | |
519 | mark_type (type, escape_status); | |
520 | } | |
521 | } | |
522 | ||
523 | /* Return true if PARENT is supertype of CHILD. Both types must be | |
524 | known to be structures or unions. */ | |
525 | ||
526 | static bool | |
527 | parent_type_p (tree parent, tree child) | |
528 | { | |
529 | int i; | |
530 | tree binfo, base_binfo; | |
531 | if (TYPE_BINFO (parent)) | |
532 | for (binfo = TYPE_BINFO (parent), i = 0; | |
533 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
534 | { | |
535 | tree binfotype = BINFO_TYPE (base_binfo); | |
536 | if (binfotype == child) | |
537 | return true; | |
538 | else if (parent_type_p (binfotype, child)) | |
539 | return true; | |
540 | } | |
541 | if (TREE_CODE (parent) == UNION_TYPE | |
542 | || TREE_CODE (parent) == QUAL_UNION_TYPE) | |
543 | { | |
544 | tree field; | |
545 | /* Search all of the variants in the union to see if one of them | |
546 | is the child. */ | |
547 | for (field = TYPE_FIELDS (parent); | |
548 | field; | |
549 | field = TREE_CHAIN (field)) | |
550 | { | |
551 | tree field_type; | |
552 | if (TREE_CODE (field) != FIELD_DECL) | |
553 | continue; | |
554 | ||
555 | field_type = TREE_TYPE (field); | |
556 | if (field_type == child) | |
557 | return true; | |
558 | } | |
559 | ||
560 | /* If we did not find it, recursively ask the variants if one of | |
561 | their children is the child type. */ | |
562 | for (field = TYPE_FIELDS (parent); | |
563 | field; | |
564 | field = TREE_CHAIN (field)) | |
565 | { | |
566 | tree field_type; | |
567 | if (TREE_CODE (field) != FIELD_DECL) | |
568 | continue; | |
569 | ||
570 | field_type = TREE_TYPE (field); | |
571 | if (TREE_CODE (field_type) == RECORD_TYPE | |
572 | || TREE_CODE (field_type) == QUAL_UNION_TYPE | |
573 | || TREE_CODE (field_type) == UNION_TYPE) | |
574 | if (parent_type_p (field_type, child)) | |
575 | return true; | |
576 | } | |
577 | } | |
578 | ||
579 | if (TREE_CODE (parent) == RECORD_TYPE) | |
580 | { | |
581 | tree field; | |
582 | for (field = TYPE_FIELDS (parent); | |
583 | field; | |
584 | field = TREE_CHAIN (field)) | |
585 | { | |
586 | tree field_type; | |
587 | if (TREE_CODE (field) != FIELD_DECL) | |
588 | continue; | |
589 | ||
590 | field_type = TREE_TYPE (field); | |
591 | if (field_type == child) | |
592 | return true; | |
593 | /* You can only cast to the first field so if it does not | |
594 | match, quit. */ | |
595 | if (TREE_CODE (field_type) == RECORD_TYPE | |
596 | || TREE_CODE (field_type) == QUAL_UNION_TYPE | |
597 | || TREE_CODE (field_type) == UNION_TYPE) | |
598 | { | |
599 | if (parent_type_p (field_type, child)) | |
600 | return true; | |
601 | else | |
602 | break; | |
603 | } | |
604 | } | |
605 | } | |
606 | return false; | |
607 | } | |
608 | ||
609 | /* Return the number of pointer tos for TYPE and return TYPE with all | |
610 | of these stripped off. */ | |
611 | ||
612 | static int | |
613 | count_stars (tree* type_ptr) | |
614 | { | |
615 | tree type = *type_ptr; | |
616 | int i = 0; | |
617 | type = TYPE_MAIN_VARIANT (type); | |
618 | while (POINTER_TYPE_P (type)) | |
619 | { | |
620 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
621 | i++; | |
622 | } | |
623 | ||
624 | *type_ptr = type; | |
625 | return i; | |
626 | } | |
627 | ||
628 | enum cast_type { | |
d4e70294 OG |
629 | CT_UP = 0x1, |
630 | CT_DOWN = 0x2, | |
631 | CT_SIDEWAYS = 0x4, | |
632 | CT_USELESS = 0x8, | |
633 | CT_FROM_P_BAD = 0x10, | |
634 | CT_FROM_NON_P = 0x20, | |
635 | CT_TO_NON_INTER = 0x40, | |
636 | CT_FROM_MALLOC = 0x80, | |
637 | CT_NO_CAST = 0x100 | |
ea900239 DB |
638 | }; |
639 | ||
640 | /* Check the cast FROM_TYPE to TO_TYPE. This function requires that | |
641 | the two types have already passed the | |
642 | ipa_type_escape_star_count_of_interesting_type test. */ | |
643 | ||
644 | static enum cast_type | |
645 | check_cast_type (tree to_type, tree from_type) | |
646 | { | |
647 | int to_stars = count_stars (&to_type); | |
648 | int from_stars = count_stars (&from_type); | |
649 | if (to_stars != from_stars) | |
650 | return CT_SIDEWAYS; | |
651 | ||
652 | if (to_type == from_type) | |
653 | return CT_USELESS; | |
654 | ||
655 | if (parent_type_p (to_type, from_type)) return CT_UP; | |
656 | if (parent_type_p (from_type, to_type)) return CT_DOWN; | |
657 | return CT_SIDEWAYS; | |
658 | } | |
659 | ||
110abdbc | 660 | /* This function returns nonzero if VAR is result of call |
d4e70294 OG |
661 | to malloc function. */ |
662 | ||
663 | static bool | |
664 | is_malloc_result (tree var) | |
665 | { | |
726a989a | 666 | gimple def_stmt; |
d4e70294 OG |
667 | |
668 | if (!var) | |
669 | return false; | |
670 | ||
671 | if (SSA_NAME_IS_DEFAULT_DEF (var)) | |
672 | return false; | |
673 | ||
674 | def_stmt = SSA_NAME_DEF_STMT (var); | |
675 | ||
726a989a | 676 | if (!is_gimple_call (def_stmt)) |
d4e70294 OG |
677 | return false; |
678 | ||
726a989a | 679 | if (var != gimple_call_lhs (def_stmt)) |
d4e70294 OG |
680 | return false; |
681 | ||
726a989a | 682 | return ((gimple_call_flags (def_stmt) & ECF_MALLOC) != 0); |
d4e70294 OG |
683 | |
684 | } | |
685 | ||
ea900239 | 686 | /* Check a cast FROM this variable, TO_TYPE. Mark the escaping types |
d4e70294 OG |
687 | if appropriate. Returns cast_type as detected. */ |
688 | ||
689 | static enum cast_type | |
ea900239 DB |
690 | check_cast (tree to_type, tree from) |
691 | { | |
692 | tree from_type = get_canon_type (TREE_TYPE (from), false, false); | |
693 | bool to_interesting_type, from_interesting_type; | |
d4e70294 | 694 | enum cast_type cast = CT_NO_CAST; |
ea900239 DB |
695 | |
696 | to_type = get_canon_type (to_type, false, false); | |
697 | if (!from_type || !to_type || from_type == to_type) | |
d4e70294 | 698 | return cast; |
ea900239 DB |
699 | |
700 | to_interesting_type = | |
701 | ipa_type_escape_star_count_of_interesting_type (to_type) >= 0; | |
702 | from_interesting_type = | |
703 | ipa_type_escape_star_count_of_interesting_type (from_type) >= 0; | |
704 | ||
705 | if (to_interesting_type) | |
706 | if (from_interesting_type) | |
707 | { | |
708 | /* Both types are interesting. This can be one of four types | |
709 | of cast: useless, up, down, or sideways. We do not care | |
710 | about up or useless. Sideways casts are always bad and | |
711 | both sides get marked as escaping. Downcasts are not | |
712 | interesting here because if type is marked as escaping, all | |
713 | of its subtypes escape. */ | |
d4e70294 OG |
714 | cast = check_cast_type (to_type, from_type); |
715 | switch (cast) | |
ea900239 DB |
716 | { |
717 | case CT_UP: | |
718 | case CT_USELESS: | |
719 | case CT_DOWN: | |
720 | break; | |
721 | ||
722 | case CT_SIDEWAYS: | |
723 | mark_type (to_type, FULL_ESCAPE); | |
724 | mark_type (from_type, FULL_ESCAPE); | |
725 | break; | |
d4e70294 OG |
726 | |
727 | default: | |
728 | break; | |
ea900239 DB |
729 | } |
730 | } | |
731 | else | |
732 | { | |
d4e70294 OG |
733 | /* This code excludes two cases from marking as escaped: |
734 | ||
735 | 1. if this is a cast of index of array of structures/unions | |
736 | that happens before accessing array element, we should not | |
737 | mark it as escaped. | |
738 | 2. if this is a cast from the local that is a result from a | |
739 | call to malloc, do not mark the cast as bad. | |
740 | ||
741 | */ | |
742 | ||
743 | if (POINTER_TYPE_P (to_type) && !POINTER_TYPE_P (from_type)) | |
744 | cast = CT_FROM_NON_P; | |
745 | else if (TREE_CODE (from) == SSA_NAME | |
746 | && is_malloc_result (from)) | |
747 | cast = CT_FROM_MALLOC; | |
748 | else | |
749 | { | |
750 | cast = CT_FROM_P_BAD; | |
751 | mark_type (to_type, FULL_ESCAPE); | |
752 | } | |
ea900239 DB |
753 | } |
754 | else if (from_interesting_type) | |
d4e70294 OG |
755 | { |
756 | mark_type (from_type, FULL_ESCAPE); | |
757 | cast = CT_TO_NON_INTER; | |
758 | } | |
759 | ||
760 | return cast; | |
761 | } | |
762 | ||
d4e70294 | 763 | |
726a989a | 764 | /* Scan assignment statement S to see if there are any casts within it. */ |
d4e70294 | 765 | |
726a989a RB |
766 | static unsigned int |
767 | look_for_casts_stmt (gimple s) | |
d4e70294 | 768 | { |
726a989a | 769 | unsigned int cast = 0; |
d4e70294 | 770 | |
726a989a | 771 | gcc_assert (is_gimple_assign (s)); |
d4e70294 | 772 | |
726a989a | 773 | if (gimple_assign_cast_p (s)) |
d4e70294 | 774 | { |
726a989a RB |
775 | tree castfromvar = gimple_assign_rhs1 (s); |
776 | cast |= check_cast (TREE_TYPE (gimple_assign_lhs (s)), castfromvar); | |
d4e70294 | 777 | } |
726a989a | 778 | else |
d4e70294 | 779 | { |
726a989a RB |
780 | size_t i; |
781 | for (i = 0; i < gimple_num_ops (s); i++) | |
782 | cast |= look_for_casts (gimple_op (s, i)); | |
783 | } | |
d4e70294 | 784 | |
726a989a RB |
785 | if (!cast) |
786 | cast = CT_NO_CAST; | |
d4e70294 | 787 | |
726a989a RB |
788 | return cast; |
789 | } | |
d4e70294 | 790 | |
d4e70294 | 791 | |
726a989a RB |
792 | typedef struct cast |
793 | { | |
794 | int type; | |
795 | gimple stmt; | |
796 | } cast_t; | |
d4e70294 OG |
797 | |
798 | /* This function is a callback for walk_use_def_chains function called | |
799 | from is_array_access_through_pointer_and_index. */ | |
800 | ||
801 | static bool | |
726a989a | 802 | is_cast_from_non_pointer (tree var, gimple def_stmt, void *data) |
d4e70294 | 803 | { |
d4e70294 OG |
804 | if (!def_stmt || !var) |
805 | return false; | |
806 | ||
726a989a | 807 | if (gimple_code (def_stmt) == GIMPLE_PHI) |
d4e70294 OG |
808 | return false; |
809 | ||
810 | if (SSA_NAME_IS_DEFAULT_DEF (var)) | |
811 | return false; | |
812 | ||
726a989a RB |
813 | if (is_gimple_assign (def_stmt)) |
814 | { | |
815 | use_operand_p use_p; | |
816 | ssa_op_iter iter; | |
817 | unsigned int cast = look_for_casts_stmt (def_stmt); | |
818 | ||
819 | /* Check that only one cast happened, and it's of non-pointer | |
820 | type. */ | |
821 | if ((cast & CT_FROM_NON_P) == (CT_FROM_NON_P) | |
822 | && (cast & ~(CT_FROM_NON_P)) == 0) | |
823 | { | |
824 | ((cast_t *)data)->stmt = def_stmt; | |
825 | ((cast_t *)data)->type++; | |
826 | ||
827 | FOR_EACH_SSA_USE_OPERAND (use_p, def_stmt, iter, SSA_OP_ALL_USES) | |
828 | { | |
829 | walk_use_def_chains (USE_FROM_PTR (use_p), | |
830 | is_cast_from_non_pointer, data, false); | |
831 | if (((cast_t*)data)->type == -1) | |
832 | break; | |
833 | } | |
834 | } | |
835 | /* Check that there is no cast, or cast is not harmful. */ | |
836 | else if ((cast & CT_NO_CAST) == (CT_NO_CAST) | |
837 | || (cast & CT_DOWN) == (CT_DOWN) | |
838 | || (cast & CT_UP) == (CT_UP) | |
839 | || (cast & CT_USELESS) == (CT_USELESS) | |
840 | || (cast & CT_FROM_MALLOC) == (CT_FROM_MALLOC)) | |
841 | { | |
842 | FOR_EACH_SSA_USE_OPERAND (use_p, def_stmt, iter, SSA_OP_ALL_USES) | |
843 | { | |
844 | walk_use_def_chains (USE_FROM_PTR (use_p), | |
845 | is_cast_from_non_pointer, data, false); | |
846 | if (((cast_t*)data)->type == -1) | |
847 | break; | |
848 | } | |
849 | } | |
850 | /* The cast is harmful. */ | |
851 | else | |
852 | ((cast_t *)data)->type = -1; | |
853 | } | |
854 | ||
d4e70294 OG |
855 | if (((cast_t*)data)->type == -1) |
856 | return true; | |
857 | ||
858 | return false; | |
859 | } | |
860 | ||
861 | /* When array element a_p[i] is accessed through the pointer a_p | |
862 | and index i, it's translated into the following sequence | |
863 | in gimple: | |
864 | ||
865 | i.1_5 = (unsigned int) i_1; | |
866 | D.1605_6 = i.1_5 * 16; | |
867 | D.1606_7 = (struct str_t *) D.1605_6; | |
868 | a_p.2_8 = a_p; | |
869 | D.1608_9 = D.1606_7 + a_p.2_8; | |
870 | ||
871 | OP0 and OP1 are of the same pointer types and stand for | |
872 | D.1606_7 and a_p.2_8 or vise versa. | |
873 | ||
874 | This function checks that: | |
875 | ||
876 | 1. one of OP0 and OP1 (D.1606_7) has passed only one cast from | |
877 | non-pointer type (D.1606_7 = (struct str_t *) D.1605_6;). | |
878 | ||
879 | 2. one of OP0 and OP1 which has passed the cast from | |
880 | non-pointer type (D.1606_7), is actually generated by multiplication of | |
881 | index by size of type to which both OP0 and OP1 point to | |
882 | (in this case D.1605_6 = i.1_5 * 16; ). | |
883 | ||
884 | 3. an address of def of the var to which was made cast (D.1605_6) | |
885 | was not taken.(How can it happen?) | |
886 | ||
887 | The following items are checked implicitly by the end of algorithm: | |
888 | ||
889 | 4. one of OP0 and OP1 (a_p.2_8) have never been cast | |
890 | (because if it was cast to pointer type, its type, that is also | |
891 | the type of OP0 and OP1, will be marked as escaped during | |
892 | analysis of casting stmt (when check_cast() is called | |
893 | from scan_for_refs for this stmt)). | |
894 | ||
895 | 5. defs of OP0 and OP1 are not passed into externally visible function | |
896 | (because if they are passed then their type, that is also the type of OP0 | |
897 | and OP1, will be marked and escaped during check_call function called from | |
898 | scan_for_refs with call stmt). | |
899 | ||
900 | In total, 1-5 guaranty that it's an access to array by pointer and index. | |
901 | ||
902 | */ | |
903 | ||
e1dc98b2 OG |
904 | bool |
905 | is_array_access_through_pointer_and_index (enum tree_code code, tree op0, | |
906 | tree op1, tree *base, tree *offset, | |
726a989a | 907 | gimple *offset_cast_stmt) |
d4e70294 | 908 | { |
726a989a RB |
909 | tree before_cast; |
910 | gimple before_cast_def_stmt; | |
d4e70294 OG |
911 | cast_t op0_cast, op1_cast; |
912 | ||
e1dc98b2 OG |
913 | *base = NULL; |
914 | *offset = NULL; | |
915 | *offset_cast_stmt = NULL; | |
916 | ||
d4e70294 | 917 | /* Check 1. */ |
e1dc98b2 OG |
918 | if (code == POINTER_PLUS_EXPR) |
919 | { | |
920 | tree op0type = TYPE_MAIN_VARIANT (TREE_TYPE (op0)); | |
921 | tree op1type = TYPE_MAIN_VARIANT (TREE_TYPE (op1)); | |
d4e70294 | 922 | |
e1dc98b2 OG |
923 | /* One of op0 and op1 is of pointer type and the other is numerical. */ |
924 | if (POINTER_TYPE_P (op0type) && NUMERICAL_TYPE_CHECK (op1type)) | |
925 | { | |
926 | *base = op0; | |
927 | *offset = op1; | |
928 | } | |
929 | else if (POINTER_TYPE_P (op1type) && NUMERICAL_TYPE_CHECK (op0type)) | |
930 | { | |
931 | *base = op1; | |
932 | *offset = op0; | |
933 | } | |
934 | else | |
935 | return false; | |
936 | } | |
937 | else | |
938 | { | |
939 | /* Init data for walk_use_def_chains function. */ | |
940 | op0_cast.type = op1_cast.type = 0; | |
941 | op0_cast.stmt = op1_cast.stmt = NULL; | |
d4e70294 | 942 | |
e1dc98b2 OG |
943 | visited_stmts = pointer_set_create (); |
944 | walk_use_def_chains (op0, is_cast_from_non_pointer,(void *)(&op0_cast), | |
945 | false); | |
946 | pointer_set_destroy (visited_stmts); | |
d4e70294 | 947 | |
e1dc98b2 OG |
948 | visited_stmts = pointer_set_create (); |
949 | walk_use_def_chains (op1, is_cast_from_non_pointer,(void *)(&op1_cast), | |
950 | false); | |
951 | pointer_set_destroy (visited_stmts); | |
d4e70294 | 952 | |
e1dc98b2 OG |
953 | if (op0_cast.type == 1 && op1_cast.type == 0) |
954 | { | |
955 | *base = op1; | |
956 | *offset = op0; | |
957 | *offset_cast_stmt = op0_cast.stmt; | |
958 | } | |
959 | else if (op0_cast.type == 0 && op1_cast.type == 1) | |
960 | { | |
961 | *base = op0; | |
962 | *offset = op1; | |
963 | *offset_cast_stmt = op1_cast.stmt; | |
964 | } | |
965 | else | |
966 | return false; | |
d4e70294 | 967 | } |
e1dc98b2 | 968 | |
d4e70294 OG |
969 | /* Check 2. |
970 | offset_cast_stmt is of the form: | |
971 | D.1606_7 = (struct str_t *) D.1605_6; */ | |
972 | ||
e1dc98b2 OG |
973 | if (*offset_cast_stmt) |
974 | { | |
975 | before_cast = SINGLE_SSA_TREE_OPERAND (*offset_cast_stmt, SSA_OP_USE); | |
976 | if (!before_cast) | |
977 | return false; | |
d4e70294 | 978 | |
e1dc98b2 OG |
979 | if (SSA_NAME_IS_DEFAULT_DEF (before_cast)) |
980 | return false; | |
d4e70294 | 981 | |
e1dc98b2 OG |
982 | before_cast_def_stmt = SSA_NAME_DEF_STMT (before_cast); |
983 | if (!before_cast_def_stmt) | |
984 | return false; | |
985 | } | |
986 | else | |
987 | before_cast_def_stmt = SSA_NAME_DEF_STMT (*offset); | |
d4e70294 OG |
988 | |
989 | /* before_cast_def_stmt should be of the form: | |
990 | D.1605_6 = i.1_5 * 16; */ | |
991 | ||
726a989a | 992 | if (is_gimple_assign (before_cast_def_stmt)) |
d4e70294 | 993 | { |
d4e70294 | 994 | /* We expect temporary here. */ |
726a989a | 995 | if (!is_gimple_reg (gimple_assign_lhs (before_cast_def_stmt))) |
d4e70294 OG |
996 | return false; |
997 | ||
726a989a | 998 | if (gimple_assign_rhs_code (before_cast_def_stmt) == MULT_EXPR) |
d4e70294 | 999 | { |
726a989a RB |
1000 | tree arg0 = gimple_assign_rhs1 (before_cast_def_stmt); |
1001 | tree arg1 = gimple_assign_rhs2 (before_cast_def_stmt); | |
d4e70294 OG |
1002 | tree unit_size = |
1003 | TYPE_SIZE_UNIT (TREE_TYPE (TYPE_MAIN_VARIANT (TREE_TYPE (op0)))); | |
1004 | ||
1005 | if (!(CONSTANT_CLASS_P (arg0) | |
726a989a | 1006 | && simple_cst_equal (arg0, unit_size)) |
d4e70294 | 1007 | && !(CONSTANT_CLASS_P (arg1) |
726a989a | 1008 | && simple_cst_equal (arg1, unit_size))) |
d4e70294 OG |
1009 | return false; |
1010 | } | |
1011 | else | |
1012 | return false; | |
1013 | } | |
1014 | else | |
1015 | return false; | |
1016 | ||
1017 | /* Check 3. | |
1018 | check that address of D.1605_6 was not taken. | |
1019 | FIXME: if D.1605_6 is gimple reg than it cannot be addressable. */ | |
1020 | ||
1021 | return true; | |
ea900239 DB |
1022 | } |
1023 | ||
1024 | /* Register the parameter and return types of function FN. The type | |
1025 | ESCAPES if the function is visible outside of the compilation | |
1026 | unit. */ | |
1027 | static void | |
1028 | check_function_parameter_and_return_types (tree fn, bool escapes) | |
1029 | { | |
1030 | tree arg; | |
1031 | ||
1032 | if (TYPE_ARG_TYPES (TREE_TYPE (fn))) | |
1033 | { | |
1034 | for (arg = TYPE_ARG_TYPES (TREE_TYPE (fn)); | |
1035 | arg && TREE_VALUE (arg) != void_type_node; | |
1036 | arg = TREE_CHAIN (arg)) | |
1037 | { | |
1038 | tree type = get_canon_type (TREE_VALUE (arg), false, false); | |
1039 | if (escapes) | |
1040 | mark_interesting_type (type, EXPOSED_PARAMETER); | |
1041 | } | |
1042 | } | |
1043 | else | |
1044 | { | |
1045 | /* FIXME - According to Geoff Keating, we should never have to | |
1046 | do this; the front ends should always process the arg list | |
1047 | from the TYPE_ARG_LIST. However, Geoff is wrong, this code | |
1048 | does seem to be live. */ | |
1049 | ||
1050 | for (arg = DECL_ARGUMENTS (fn); arg; arg = TREE_CHAIN (arg)) | |
1051 | { | |
1052 | tree type = get_canon_type (TREE_TYPE (arg), false, false); | |
1053 | if (escapes) | |
1054 | mark_interesting_type (type, EXPOSED_PARAMETER); | |
1055 | } | |
1056 | } | |
1057 | if (escapes) | |
1058 | { | |
1059 | tree type = get_canon_type (TREE_TYPE (TREE_TYPE (fn)), false, false); | |
1060 | mark_interesting_type (type, EXPOSED_PARAMETER); | |
1061 | } | |
1062 | } | |
1063 | ||
1064 | /* Return true if the variable T is the right kind of static variable to | |
1065 | perform compilation unit scope escape analysis. */ | |
1066 | ||
1067 | static inline void | |
1068 | has_proper_scope_for_analysis (tree t) | |
1069 | { | |
1070 | /* If the variable has the "used" attribute, treat it as if it had a | |
1071 | been touched by the devil. */ | |
1072 | tree type = get_canon_type (TREE_TYPE (t), false, false); | |
1073 | if (!type) return; | |
1074 | ||
1075 | if (lookup_attribute ("used", DECL_ATTRIBUTES (t))) | |
1076 | { | |
1077 | mark_interesting_type (type, FULL_ESCAPE); | |
1078 | return; | |
1079 | } | |
1080 | ||
1081 | /* Do not want to do anything with volatile except mark any | |
1082 | function that uses one to be not const or pure. */ | |
1083 | if (TREE_THIS_VOLATILE (t)) | |
1084 | return; | |
1085 | ||
1086 | /* Do not care about a local automatic that is not static. */ | |
1087 | if (!TREE_STATIC (t) && !DECL_EXTERNAL (t)) | |
1088 | return; | |
1089 | ||
1090 | if (DECL_EXTERNAL (t) || TREE_PUBLIC (t)) | |
1091 | { | |
1092 | /* If the front end set the variable to be READONLY and | |
1093 | constant, we can allow this variable in pure or const | |
1094 | functions but the scope is too large for our analysis to set | |
1095 | these bits ourselves. */ | |
1096 | ||
1097 | if (TREE_READONLY (t) | |
1098 | && DECL_INITIAL (t) | |
1099 | && is_gimple_min_invariant (DECL_INITIAL (t))) | |
1100 | ; /* Read of a constant, do not change the function state. */ | |
1101 | else | |
1102 | { | |
1103 | /* The type escapes for all public and externs. */ | |
1104 | mark_interesting_type (type, FULL_ESCAPE); | |
1105 | } | |
1106 | } | |
1107 | } | |
1108 | ||
1109 | /* If T is a VAR_DECL for a static that we are interested in, add the | |
1110 | uid to the bitmap. */ | |
1111 | ||
1112 | static void | |
1113 | check_operand (tree t) | |
1114 | { | |
1115 | if (!t) return; | |
1116 | ||
1117 | /* This is an assignment from a function, register the types as | |
1118 | escaping. */ | |
1119 | if (TREE_CODE (t) == FUNCTION_DECL) | |
1120 | check_function_parameter_and_return_types (t, true); | |
1121 | ||
1122 | else if (TREE_CODE (t) == VAR_DECL) | |
1123 | has_proper_scope_for_analysis (t); | |
1124 | } | |
1125 | ||
1126 | /* Examine tree T for references. */ | |
1127 | ||
1128 | static void | |
1129 | check_tree (tree t) | |
1130 | { | |
1131 | if ((TREE_CODE (t) == EXC_PTR_EXPR) || (TREE_CODE (t) == FILTER_EXPR)) | |
1132 | return; | |
1133 | ||
d4e70294 OG |
1134 | /* We want to catch here also REALPART_EXPR and IMAGEPART_EXPR, |
1135 | but they already included in handled_component_p. */ | |
1136 | while (handled_component_p (t)) | |
ea900239 DB |
1137 | { |
1138 | if (TREE_CODE (t) == ARRAY_REF) | |
1139 | check_operand (TREE_OPERAND (t, 1)); | |
1140 | t = TREE_OPERAND (t, 0); | |
1141 | } | |
1142 | ||
1143 | if (INDIRECT_REF_P (t)) | |
1144 | /* || TREE_CODE (t) == MEM_REF) */ | |
1145 | check_tree (TREE_OPERAND (t, 0)); | |
1146 | ||
1147 | if (SSA_VAR_P (t) || (TREE_CODE (t) == FUNCTION_DECL)) | |
726a989a RB |
1148 | { |
1149 | check_operand (t); | |
1150 | if (DECL_P (t) && DECL_INITIAL (t)) | |
1151 | check_tree (DECL_INITIAL (t)); | |
1152 | } | |
ea900239 DB |
1153 | } |
1154 | ||
1155 | /* Create an address_of edge FROM_TYPE.TO_TYPE. */ | |
1156 | static void | |
1157 | mark_interesting_addressof (tree to_type, tree from_type) | |
1158 | { | |
1159 | int from_uid; | |
1160 | int to_uid; | |
1161 | bitmap type_map; | |
1162 | splay_tree_node result; | |
1163 | ||
1164 | from_type = get_canon_type (from_type, false, false); | |
1165 | to_type = get_canon_type (to_type, false, false); | |
1166 | ||
1167 | if (!from_type || !to_type) | |
1168 | return; | |
1169 | ||
1170 | from_uid = TYPE_UID (from_type); | |
1171 | to_uid = TYPE_UID (to_type); | |
1172 | ||
1173 | gcc_assert (ipa_type_escape_star_count_of_interesting_type (from_type) == 0); | |
1174 | ||
1175 | /* Process the Y into X map pointer. */ | |
1176 | result = splay_tree_lookup (uid_to_addressof_down_map, | |
1177 | (splay_tree_key) from_uid); | |
1178 | ||
1179 | if (result) | |
1180 | type_map = (bitmap) result->value; | |
1181 | else | |
1182 | { | |
1183 | type_map = BITMAP_ALLOC (&ipa_obstack); | |
1184 | splay_tree_insert (uid_to_addressof_down_map, | |
1185 | from_uid, | |
1186 | (splay_tree_value)type_map); | |
1187 | } | |
1188 | bitmap_set_bit (type_map, TYPE_UID (to_type)); | |
1189 | ||
1190 | /* Process the X into Y reverse map pointer. */ | |
1191 | result = | |
1192 | splay_tree_lookup (uid_to_addressof_up_map, (splay_tree_key) to_uid); | |
1193 | ||
1194 | if (result) | |
1195 | type_map = (bitmap) result->value; | |
1196 | else | |
1197 | { | |
1198 | type_map = BITMAP_ALLOC (&ipa_obstack); | |
1199 | splay_tree_insert (uid_to_addressof_up_map, | |
1200 | to_uid, | |
1201 | (splay_tree_value)type_map); | |
1202 | } | |
d4e70294 | 1203 | bitmap_set_bit (type_map, TYPE_UID (from_type)); |
ea900239 DB |
1204 | } |
1205 | ||
1206 | /* Scan tree T to see if there are any addresses taken in within T. */ | |
1207 | ||
1208 | static void | |
1209 | look_for_address_of (tree t) | |
1210 | { | |
1211 | if (TREE_CODE (t) == ADDR_EXPR) | |
1212 | { | |
1213 | tree x = get_base_var (t); | |
1214 | tree cref = TREE_OPERAND (t, 0); | |
1215 | ||
1216 | /* If we have an expression of the form "&a.b.c.d", mark a.b, | |
1217 | b.c and c.d. as having its address taken. */ | |
1218 | tree fielddecl = NULL_TREE; | |
1219 | while (cref!= x) | |
1220 | { | |
1221 | if (TREE_CODE (cref) == COMPONENT_REF) | |
1222 | { | |
1223 | fielddecl = TREE_OPERAND (cref, 1); | |
1224 | mark_interesting_addressof (TREE_TYPE (fielddecl), | |
1225 | DECL_FIELD_CONTEXT (fielddecl)); | |
1226 | } | |
1227 | else if (TREE_CODE (cref) == ARRAY_REF) | |
1228 | get_canon_type (TREE_TYPE (cref), false, false); | |
1229 | ||
1230 | cref = TREE_OPERAND (cref, 0); | |
1231 | } | |
1232 | ||
1233 | if (TREE_CODE (x) == VAR_DECL) | |
1234 | has_proper_scope_for_analysis (x); | |
1235 | } | |
1236 | } | |
1237 | ||
1238 | ||
726a989a | 1239 | /* Scan tree T to see if there are any casts within it. */ |
ea900239 | 1240 | |
d4e70294 | 1241 | static unsigned int |
726a989a | 1242 | look_for_casts (tree t) |
ea900239 | 1243 | { |
d4e70294 OG |
1244 | unsigned int cast = 0; |
1245 | ||
ea900239 DB |
1246 | if (is_gimple_cast (t) || TREE_CODE (t) == VIEW_CONVERT_EXPR) |
1247 | { | |
1248 | tree castfromvar = TREE_OPERAND (t, 0); | |
d4e70294 | 1249 | cast = cast | check_cast (TREE_TYPE (t), castfromvar); |
ea900239 | 1250 | } |
44d974b5 OG |
1251 | else |
1252 | while (handled_component_p (t)) | |
1253 | { | |
1254 | t = TREE_OPERAND (t, 0); | |
1255 | if (TREE_CODE (t) == VIEW_CONVERT_EXPR) | |
1256 | { | |
1257 | /* This may be some part of a component ref. | |
1258 | IE it may be a.b.VIEW_CONVERT_EXPR<weird_type>(c).d, AFAIK. | |
1259 | castfromref will give you a.b.c, not a. */ | |
1260 | tree castfromref = TREE_OPERAND (t, 0); | |
1261 | cast = cast | check_cast (TREE_TYPE (t), castfromref); | |
1262 | } | |
1263 | else if (TREE_CODE (t) == COMPONENT_REF) | |
1264 | get_canon_type (TREE_TYPE (TREE_OPERAND (t, 1)), false, false); | |
1265 | } | |
d4e70294 OG |
1266 | |
1267 | if (!cast) | |
1268 | cast = CT_NO_CAST; | |
1269 | return cast; | |
ea900239 DB |
1270 | } |
1271 | ||
1272 | /* Check to see if T is a read or address of operation on a static var | |
1273 | we are interested in analyzing. */ | |
1274 | ||
1275 | static void | |
1276 | check_rhs_var (tree t) | |
1277 | { | |
1278 | look_for_address_of (t); | |
726a989a | 1279 | check_tree (t); |
ea900239 DB |
1280 | } |
1281 | ||
1282 | /* Check to see if T is an assignment to a static var we are | |
1283 | interested in analyzing. */ | |
1284 | ||
1285 | static void | |
1286 | check_lhs_var (tree t) | |
1287 | { | |
726a989a | 1288 | check_tree (t); |
ea900239 DB |
1289 | } |
1290 | ||
1291 | /* This is a scaled down version of get_asm_expr_operands from | |
1292 | tree_ssa_operands.c. The version there runs much later and assumes | |
1293 | that aliasing information is already available. Here we are just | |
1294 | trying to find if the set of inputs and outputs contain references | |
1295 | or address of operations to local. FN is the function being | |
1296 | analyzed and STMT is the actual asm statement. */ | |
1297 | ||
1298 | static void | |
726a989a | 1299 | check_asm (gimple stmt) |
ea900239 | 1300 | { |
726a989a | 1301 | size_t i; |
ea900239 | 1302 | |
726a989a RB |
1303 | for (i = 0; i < gimple_asm_noutputs (stmt); i++) |
1304 | check_lhs_var (gimple_asm_output_op (stmt, i)); | |
1305 | ||
1306 | for (i = 0; i < gimple_asm_ninputs (stmt); i++) | |
1307 | check_rhs_var (gimple_asm_input_op (stmt, i)); | |
ea900239 DB |
1308 | |
1309 | /* There is no code here to check for asm memory clobbers. The | |
1310 | casual maintainer might think that such code would be necessary, | |
1311 | but that appears to be wrong. In other parts of the compiler, | |
1312 | the asm memory clobbers are assumed to only clobber variables | |
1313 | that are addressable. All types with addressable instances are | |
1314 | assumed to already escape. So, we are protected here. */ | |
1315 | } | |
1316 | ||
726a989a RB |
1317 | |
1318 | /* Check the parameters of function call to CALL to mark the | |
ea900239 DB |
1319 | types that pass across the function boundary. Also check to see if |
1320 | this is either an indirect call, a call outside the compilation | |
1321 | unit. */ | |
1322 | ||
d4e70294 | 1323 | static void |
726a989a | 1324 | check_call (gimple call) |
ea900239 | 1325 | { |
726a989a | 1326 | tree callee_t = gimple_call_fndecl (call); |
ea900239 DB |
1327 | struct cgraph_node* callee; |
1328 | enum availability avail = AVAIL_NOT_AVAILABLE; | |
726a989a | 1329 | size_t i; |
ea900239 | 1330 | |
726a989a RB |
1331 | for (i = 0; i < gimple_call_num_args (call); i++) |
1332 | check_rhs_var (gimple_call_arg (call, i)); | |
ea900239 DB |
1333 | |
1334 | if (callee_t) | |
1335 | { | |
1336 | tree arg_type; | |
1337 | tree last_arg_type = NULL; | |
1338 | callee = cgraph_node(callee_t); | |
1339 | avail = cgraph_function_body_availability (callee); | |
1340 | ||
1341 | /* Check that there are no implicit casts in the passing of | |
1342 | parameters. */ | |
1343 | if (TYPE_ARG_TYPES (TREE_TYPE (callee_t))) | |
1344 | { | |
726a989a | 1345 | for (arg_type = TYPE_ARG_TYPES (TREE_TYPE (callee_t)), i = 0; |
ea900239 | 1346 | arg_type && TREE_VALUE (arg_type) != void_type_node; |
726a989a | 1347 | arg_type = TREE_CHAIN (arg_type), i++) |
ea900239 | 1348 | { |
726a989a | 1349 | tree operand = gimple_call_arg (call, i); |
ea900239 DB |
1350 | if (operand) |
1351 | { | |
ea900239 | 1352 | last_arg_type = TREE_VALUE(arg_type); |
5039610b | 1353 | check_cast (last_arg_type, operand); |
ea900239 DB |
1354 | } |
1355 | else | |
1356 | /* The code reaches here for some unfortunate | |
1357 | builtin functions that do not have a list of | |
1358 | argument types. */ | |
1359 | break; | |
1360 | } | |
1361 | } | |
1362 | else | |
1363 | { | |
1364 | /* FIXME - According to Geoff Keating, we should never | |
1365 | have to do this; the front ends should always process | |
1366 | the arg list from the TYPE_ARG_LIST. */ | |
726a989a | 1367 | for (arg_type = DECL_ARGUMENTS (callee_t), i = 0; |
ea900239 | 1368 | arg_type; |
726a989a | 1369 | arg_type = TREE_CHAIN (arg_type), i++) |
ea900239 | 1370 | { |
726a989a | 1371 | tree operand = gimple_call_arg (call, i); |
ea900239 DB |
1372 | if (operand) |
1373 | { | |
726a989a | 1374 | last_arg_type = TREE_TYPE (arg_type); |
5039610b | 1375 | check_cast (last_arg_type, operand); |
ea900239 DB |
1376 | } |
1377 | else | |
1378 | /* The code reaches here for some unfortunate | |
1379 | builtin functions that do not have a list of | |
1380 | argument types. */ | |
1381 | break; | |
1382 | } | |
1383 | } | |
1384 | ||
1385 | /* In the case where we have a var_args function, we need to | |
1386 | check the remaining parameters against the last argument. */ | |
1387 | arg_type = last_arg_type; | |
726a989a | 1388 | for ( ; i < gimple_call_num_args (call); i++) |
ea900239 | 1389 | { |
726a989a | 1390 | tree operand = gimple_call_arg (call, i); |
ea900239 | 1391 | if (arg_type) |
5039610b | 1392 | check_cast (arg_type, operand); |
ea900239 DB |
1393 | else |
1394 | { | |
1395 | /* The code reaches here for some unfortunate | |
1396 | builtin functions that do not have a list of | |
1397 | argument types. Most of these functions have | |
1398 | been marked as having their parameters not | |
1399 | escape, but for the rest, the type is doomed. */ | |
5039610b | 1400 | tree type = get_canon_type (TREE_TYPE (operand), false, false); |
ea900239 DB |
1401 | mark_interesting_type (type, FULL_ESCAPE); |
1402 | } | |
1403 | } | |
1404 | } | |
1405 | ||
1406 | /* The callee is either unknown (indirect call) or there is just no | |
1407 | scannable code for it (external call) . We look to see if there | |
1408 | are any bits available for the callee (such as by declaration or | |
1409 | because it is builtin) and process solely on the basis of those | |
1410 | bits. */ | |
ea900239 DB |
1411 | if (avail == AVAIL_NOT_AVAILABLE || avail == AVAIL_OVERWRITABLE) |
1412 | { | |
1413 | /* If this is a direct call to an external function, mark all of | |
1414 | the parameter and return types. */ | |
726a989a | 1415 | for (i = 0; i < gimple_call_num_args (call); i++) |
ea900239 | 1416 | { |
726a989a | 1417 | tree operand = gimple_call_arg (call, i); |
5039610b | 1418 | tree type = get_canon_type (TREE_TYPE (operand), false, false); |
ea900239 | 1419 | mark_interesting_type (type, EXPOSED_PARAMETER); |
726a989a | 1420 | } |
ea900239 DB |
1421 | |
1422 | if (callee_t) | |
1423 | { | |
1424 | tree type = | |
1425 | get_canon_type (TREE_TYPE (TREE_TYPE (callee_t)), false, false); | |
1426 | mark_interesting_type (type, EXPOSED_PARAMETER); | |
1427 | } | |
1428 | } | |
ea900239 DB |
1429 | } |
1430 | ||
1431 | /* CODE is the operation on OP0 and OP1. OP0 is the operand that we | |
1432 | *know* is a pointer type. OP1 may be a pointer type. */ | |
1433 | static bool | |
1434 | okay_pointer_operation (enum tree_code code, tree op0, tree op1) | |
1435 | { | |
1436 | tree op0type = TYPE_MAIN_VARIANT (TREE_TYPE (op0)); | |
d4e70294 | 1437 | |
ea900239 DB |
1438 | switch (code) |
1439 | { | |
1440 | case MULT_EXPR: | |
d4e70294 OG |
1441 | /* Multiplication does not change alignment. */ |
1442 | return true; | |
1443 | break; | |
ea900239 | 1444 | case MINUS_EXPR: |
d4e70294 | 1445 | case PLUS_EXPR: |
e1dc98b2 | 1446 | case POINTER_PLUS_EXPR: |
d4e70294 | 1447 | { |
726a989a RB |
1448 | tree base, offset; |
1449 | gimple offset_cast_stmt; | |
e1dc98b2 OG |
1450 | |
1451 | if (POINTER_TYPE_P (op0type) | |
d4e70294 OG |
1452 | && TREE_CODE (op0) == SSA_NAME |
1453 | && TREE_CODE (op1) == SSA_NAME | |
e1dc98b2 OG |
1454 | && is_array_access_through_pointer_and_index (code, op0, op1, |
1455 | &base, | |
1456 | &offset, | |
1457 | &offset_cast_stmt)) | |
d4e70294 OG |
1458 | return true; |
1459 | else | |
1460 | { | |
1461 | tree size_of_op0_points_to = TYPE_SIZE_UNIT (TREE_TYPE (op0type)); | |
1462 | ||
1463 | if (CONSTANT_CLASS_P (op1) | |
1464 | && size_of_op0_points_to | |
1465 | && multiple_of_p (TREE_TYPE (size_of_op0_points_to), | |
1466 | op1, size_of_op0_points_to)) | |
1467 | return true; | |
ea900239 | 1468 | |
d4e70294 OG |
1469 | if (CONSTANT_CLASS_P (op0) |
1470 | && size_of_op0_points_to | |
1471 | && multiple_of_p (TREE_TYPE (size_of_op0_points_to), | |
1472 | op0, size_of_op0_points_to)) | |
1473 | return true; | |
1474 | } | |
1475 | } | |
1476 | break; | |
ea900239 DB |
1477 | default: |
1478 | return false; | |
1479 | } | |
1480 | return false; | |
1481 | } | |
1482 | ||
ea900239 | 1483 | |
ea900239 | 1484 | |
726a989a RB |
1485 | /* Helper for scan_for_refs. Check the operands of an assignment to |
1486 | mark types that may escape. */ | |
1487 | ||
1488 | static void | |
1489 | check_assign (gimple t) | |
ea900239 | 1490 | { |
726a989a RB |
1491 | /* First look on the lhs and see what variable is stored to */ |
1492 | check_lhs_var (gimple_assign_lhs (t)); | |
1493 | ||
1494 | /* For the purposes of figuring out what the cast affects */ | |
ea900239 | 1495 | |
726a989a RB |
1496 | /* Next check the operands on the rhs to see if they are ok. */ |
1497 | switch (TREE_CODE_CLASS (gimple_assign_rhs_code (t))) | |
ea900239 | 1498 | { |
726a989a RB |
1499 | case tcc_binary: |
1500 | { | |
1501 | tree op0 = gimple_assign_rhs1 (t); | |
1502 | tree type0 = get_canon_type (TREE_TYPE (op0), false, false); | |
1503 | tree op1 = gimple_assign_rhs2 (t); | |
1504 | tree type1 = get_canon_type (TREE_TYPE (op1), false, false); | |
1505 | ||
1506 | /* If this is pointer arithmetic of any bad sort, then | |
1507 | we need to mark the types as bad. For binary | |
1508 | operations, no binary operator we currently support | |
1509 | is always "safe" in regard to what it would do to | |
1510 | pointers for purposes of determining which types | |
1511 | escape, except operations of the size of the type. | |
1512 | It is possible that min and max under the right set | |
1513 | of circumstances and if the moon is in the correct | |
1514 | place could be safe, but it is hard to see how this | |
1515 | is worth the effort. */ | |
1516 | if (type0 && POINTER_TYPE_P (type0) | |
1517 | && !okay_pointer_operation (gimple_assign_rhs_code (t), op0, op1)) | |
1518 | mark_interesting_type (type0, FULL_ESCAPE); | |
1519 | ||
1520 | if (type1 && POINTER_TYPE_P (type1) | |
1521 | && !okay_pointer_operation (gimple_assign_rhs_code (t), op1, op0)) | |
1522 | mark_interesting_type (type1, FULL_ESCAPE); | |
1523 | ||
1524 | look_for_casts (op0); | |
1525 | look_for_casts (op1); | |
1526 | check_rhs_var (op0); | |
1527 | check_rhs_var (op1); | |
1528 | } | |
ea900239 DB |
1529 | break; |
1530 | ||
726a989a | 1531 | case tcc_unary: |
ea900239 | 1532 | { |
726a989a RB |
1533 | tree op0 = gimple_assign_rhs1 (t); |
1534 | tree type0 = get_canon_type (TREE_TYPE (op0), false, false); | |
1535 | ||
1536 | /* For unary operations, if the operation is NEGATE or ABS on | |
1537 | a pointer, this is also considered pointer arithmetic and | |
1538 | thus, bad for business. */ | |
1539 | if (type0 | |
1540 | && POINTER_TYPE_P (type0) | |
1541 | && (TREE_CODE (op0) == NEGATE_EXPR | |
1542 | || TREE_CODE (op0) == ABS_EXPR)) | |
1543 | mark_interesting_type (type0, FULL_ESCAPE); | |
1544 | ||
1545 | check_rhs_var (op0); | |
1546 | look_for_casts (op0); | |
1547 | } | |
1548 | break; | |
ea900239 | 1549 | |
726a989a RB |
1550 | case tcc_reference: |
1551 | look_for_casts (gimple_assign_rhs1 (t)); | |
1552 | check_rhs_var (gimple_assign_rhs1 (t)); | |
1553 | break; | |
ea900239 | 1554 | |
726a989a RB |
1555 | case tcc_declaration: |
1556 | check_rhs_var (gimple_assign_rhs1 (t)); | |
1557 | break; | |
ea900239 | 1558 | |
726a989a RB |
1559 | case tcc_expression: |
1560 | if (gimple_assign_rhs_code (t) == ADDR_EXPR) | |
1561 | { | |
1562 | tree rhs = gimple_assign_rhs1 (t); | |
1563 | look_for_casts (TREE_OPERAND (rhs, 0)); | |
1564 | check_rhs_var (rhs); | |
1565 | } | |
1566 | break; | |
ea900239 | 1567 | |
726a989a | 1568 | default: |
ea900239 | 1569 | break; |
726a989a RB |
1570 | } |
1571 | } | |
1572 | ||
ea900239 | 1573 | |
726a989a RB |
1574 | /* Scan statement T for references to types and mark anything |
1575 | interesting. */ | |
1576 | ||
1577 | static void | |
1578 | scan_for_refs (gimple t) | |
1579 | { | |
1580 | switch (gimple_code (t)) | |
1581 | { | |
1582 | case GIMPLE_ASSIGN: | |
1583 | check_assign (t); | |
ea900239 DB |
1584 | break; |
1585 | ||
726a989a RB |
1586 | case GIMPLE_CALL: |
1587 | /* If this is a call to malloc, squirrel away the result so we | |
1588 | do mark the resulting cast as being bad. */ | |
ea900239 | 1589 | check_call (t); |
ea900239 DB |
1590 | break; |
1591 | ||
726a989a RB |
1592 | case GIMPLE_ASM: |
1593 | check_asm (t); | |
ea900239 DB |
1594 | break; |
1595 | ||
1596 | default: | |
1597 | break; | |
1598 | } | |
726a989a RB |
1599 | |
1600 | return; | |
ea900239 DB |
1601 | } |
1602 | ||
1603 | ||
1604 | /* The init routine for analyzing global static variable usage. See | |
1605 | comments at top for description. */ | |
1606 | static void | |
1607 | ipa_init (void) | |
1608 | { | |
1609 | bitmap_obstack_initialize (&ipa_obstack); | |
1610 | global_types_exposed_parameter = BITMAP_ALLOC (&ipa_obstack); | |
1611 | global_types_full_escape = BITMAP_ALLOC (&ipa_obstack); | |
1612 | global_types_seen = BITMAP_ALLOC (&ipa_obstack); | |
ea900239 DB |
1613 | |
1614 | uid_to_canon_type = splay_tree_new (splay_tree_compare_ints, 0, 0); | |
1615 | all_canon_types = splay_tree_new (compare_type_brand, 0, 0); | |
1616 | type_to_canon_type = splay_tree_new (splay_tree_compare_pointers, 0, 0); | |
1617 | uid_to_subtype_map = splay_tree_new (splay_tree_compare_ints, 0, 0); | |
1618 | uid_to_addressof_down_map = splay_tree_new (splay_tree_compare_ints, 0, 0); | |
1619 | uid_to_addressof_up_map = splay_tree_new (splay_tree_compare_ints, 0, 0); | |
1620 | ||
1621 | /* There are some shared nodes, in particular the initializers on | |
1622 | static declarations. We do not need to scan them more than once | |
1623 | since all we would be interested in are the addressof | |
1624 | operations. */ | |
1625 | visited_nodes = pointer_set_create (); | |
1626 | initialized = true; | |
1627 | } | |
1628 | ||
1629 | /* Check out the rhs of a static or global initialization VNODE to see | |
1630 | if any of them contain addressof operations. Note that some of | |
6738920f | 1631 | these variables may not even be referenced in the code in this |
ea900239 DB |
1632 | compilation unit but their right hand sides may contain references |
1633 | to variables defined within this unit. */ | |
1634 | ||
1635 | static void | |
8a4a83ed | 1636 | analyze_variable (struct varpool_node *vnode) |
ea900239 DB |
1637 | { |
1638 | tree global = vnode->decl; | |
1639 | tree type = get_canon_type (TREE_TYPE (global), false, false); | |
1640 | ||
1641 | /* If this variable has exposure beyond the compilation unit, add | |
1642 | its type to the global types. */ | |
1643 | ||
1644 | if (vnode->externally_visible) | |
1645 | mark_interesting_type (type, FULL_ESCAPE); | |
1646 | ||
dd2c9f74 VR |
1647 | gcc_assert (TREE_CODE (global) == VAR_DECL); |
1648 | ||
1649 | if (DECL_INITIAL (global)) | |
726a989a | 1650 | check_tree (DECL_INITIAL (global)); |
ea900239 DB |
1651 | } |
1652 | ||
1653 | /* This is the main routine for finding the reference patterns for | |
1654 | global variables within a function FN. */ | |
1655 | ||
1656 | static void | |
1657 | analyze_function (struct cgraph_node *fn) | |
1658 | { | |
1659 | tree decl = fn->decl; | |
1660 | check_function_parameter_and_return_types (decl, | |
1661 | fn->local.externally_visible); | |
1662 | if (dump_file) | |
1663 | fprintf (dump_file, "\n local analysis of %s", cgraph_node_name (fn)); | |
1664 | ||
1665 | { | |
1666 | struct function *this_cfun = DECL_STRUCT_FUNCTION (decl); | |
1667 | basic_block this_block; | |
1668 | ||
1669 | FOR_EACH_BB_FN (this_block, this_cfun) | |
1670 | { | |
726a989a RB |
1671 | gimple_stmt_iterator gsi; |
1672 | for (gsi = gsi_start_bb (this_block); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1673 | scan_for_refs (gsi_stmt (gsi)); | |
ea900239 DB |
1674 | } |
1675 | } | |
1676 | ||
1677 | /* There may be const decls with interesting right hand sides. */ | |
1678 | if (DECL_STRUCT_FUNCTION (decl)) | |
1679 | { | |
1680 | tree step; | |
cb91fab0 | 1681 | for (step = DECL_STRUCT_FUNCTION (decl)->local_decls; |
ea900239 DB |
1682 | step; |
1683 | step = TREE_CHAIN (step)) | |
1684 | { | |
1685 | tree var = TREE_VALUE (step); | |
1686 | if (TREE_CODE (var) == VAR_DECL | |
1687 | && DECL_INITIAL (var) | |
1688 | && !TREE_STATIC (var)) | |
726a989a | 1689 | check_tree (DECL_INITIAL (var)); |
ea900239 DB |
1690 | get_canon_type (TREE_TYPE (var), false, false); |
1691 | } | |
1692 | } | |
1693 | } | |
1694 | ||
1695 | \f | |
1696 | ||
1697 | /* Convert a type_UID into a type. */ | |
1698 | static tree | |
1699 | type_for_uid (int uid) | |
1700 | { | |
1701 | splay_tree_node result = | |
1702 | splay_tree_lookup (uid_to_canon_type, (splay_tree_key) uid); | |
1703 | ||
1704 | if (result) | |
1705 | return (tree) result->value; | |
1706 | else return NULL; | |
1707 | } | |
1708 | ||
fa10beec | 1709 | /* Return a bitmap with the subtypes of the type for UID. If it |
ea900239 DB |
1710 | does not exist, return either NULL or a new bitmap depending on the |
1711 | value of CREATE. */ | |
1712 | ||
1713 | static bitmap | |
1714 | subtype_map_for_uid (int uid, bool create) | |
1715 | { | |
1716 | splay_tree_node result = splay_tree_lookup (uid_to_subtype_map, | |
1717 | (splay_tree_key) uid); | |
1718 | ||
1719 | if (result) | |
1720 | return (bitmap) result->value; | |
1721 | else if (create) | |
1722 | { | |
1723 | bitmap subtype_map = BITMAP_ALLOC (&ipa_obstack); | |
1724 | splay_tree_insert (uid_to_subtype_map, | |
1725 | uid, | |
1726 | (splay_tree_value)subtype_map); | |
1727 | return subtype_map; | |
1728 | } | |
1729 | else return NULL; | |
1730 | } | |
1731 | ||
1732 | /* Mark all of the supertypes and field types of TYPE as being seen. | |
1733 | Also accumulate the subtypes for each type so that | |
1734 | close_types_full_escape can mark a subtype as escaping if the | |
1735 | supertype escapes. */ | |
1736 | ||
1737 | static void | |
1738 | close_type_seen (tree type) | |
1739 | { | |
1740 | tree field; | |
1741 | int i, uid; | |
1742 | tree binfo, base_binfo; | |
1743 | ||
1744 | /* See thru all pointer tos and array ofs. */ | |
1745 | type = get_canon_type (type, true, true); | |
1746 | if (!type) | |
1747 | return; | |
1748 | ||
1749 | uid = TYPE_UID (type); | |
1750 | ||
1751 | if (bitmap_bit_p (been_there_done_that, uid)) | |
1752 | return; | |
1753 | bitmap_set_bit (been_there_done_that, uid); | |
1754 | ||
a4174ebf | 1755 | /* If we are doing a language with a type hierarchy, mark all of |
ea900239 DB |
1756 | the superclasses. */ |
1757 | if (TYPE_BINFO (type)) | |
1758 | for (binfo = TYPE_BINFO (type), i = 0; | |
1759 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
1760 | { | |
1761 | tree binfo_type = BINFO_TYPE (base_binfo); | |
1762 | bitmap subtype_map = subtype_map_for_uid | |
1763 | (TYPE_UID (TYPE_MAIN_VARIANT (binfo_type)), true); | |
1764 | bitmap_set_bit (subtype_map, uid); | |
1765 | close_type_seen (get_canon_type (binfo_type, true, true)); | |
1766 | } | |
1767 | ||
1768 | /* If the field is a struct or union type, mark all of the | |
1769 | subfields. */ | |
1770 | for (field = TYPE_FIELDS (type); | |
1771 | field; | |
1772 | field = TREE_CHAIN (field)) | |
1773 | { | |
1774 | tree field_type; | |
1775 | if (TREE_CODE (field) != FIELD_DECL) | |
1776 | continue; | |
1777 | ||
1778 | field_type = TREE_TYPE (field); | |
1779 | if (ipa_type_escape_star_count_of_interesting_or_array_type (field_type) >= 0) | |
1780 | close_type_seen (get_canon_type (field_type, true, true)); | |
1781 | } | |
1782 | } | |
1783 | ||
1784 | /* Take a TYPE that has been passed by value to an external function | |
1785 | and mark all of the fields that have pointer types as escaping. For | |
1786 | any of the non pointer types that are structures or unions, | |
1787 | recurse. TYPE is never a pointer type. */ | |
1788 | ||
1789 | static void | |
1790 | close_type_exposed_parameter (tree type) | |
1791 | { | |
1792 | tree field; | |
1793 | int uid; | |
1794 | ||
1795 | type = get_canon_type (type, false, false); | |
1796 | if (!type) | |
1797 | return; | |
1798 | uid = TYPE_UID (type); | |
1799 | gcc_assert (!POINTER_TYPE_P (type)); | |
1800 | ||
1801 | if (bitmap_bit_p (been_there_done_that, uid)) | |
1802 | return; | |
1803 | bitmap_set_bit (been_there_done_that, uid); | |
1804 | ||
1805 | /* If the field is a struct or union type, mark all of the | |
1806 | subfields. */ | |
1807 | for (field = TYPE_FIELDS (type); | |
1808 | field; | |
1809 | field = TREE_CHAIN (field)) | |
1810 | { | |
1811 | tree field_type; | |
1812 | ||
1813 | if (TREE_CODE (field) != FIELD_DECL) | |
1814 | continue; | |
1815 | ||
1816 | field_type = get_canon_type (TREE_TYPE (field), false, false); | |
1817 | mark_interesting_type (field_type, EXPOSED_PARAMETER); | |
1818 | ||
1819 | /* Only recurse for non pointer types of structures and unions. */ | |
1820 | if (ipa_type_escape_star_count_of_interesting_type (field_type) == 0) | |
1821 | close_type_exposed_parameter (field_type); | |
1822 | } | |
1823 | } | |
1824 | ||
1825 | /* The next function handles the case where a type fully escapes. | |
1826 | This means that not only does the type itself escape, | |
1827 | ||
1828 | a) the type of every field recursively escapes | |
1829 | b) the type of every subtype escapes as well as the super as well | |
1830 | as all of the pointer to types for each field. | |
1831 | ||
1832 | Note that pointer to types are not marked as escaping. If the | |
1833 | pointed to type escapes, the pointer to type also escapes. | |
1834 | ||
1835 | Take a TYPE that has had the address taken for an instance of it | |
1836 | and mark all of the types for its fields as having their addresses | |
1837 | taken. */ | |
1838 | ||
1839 | static void | |
1840 | close_type_full_escape (tree type) | |
1841 | { | |
1842 | tree field; | |
1843 | unsigned int i; | |
1844 | int uid; | |
1845 | tree binfo, base_binfo; | |
1846 | bitmap_iterator bi; | |
1847 | bitmap subtype_map; | |
1848 | splay_tree_node address_result; | |
1849 | ||
1850 | /* Strip off any pointer or array types. */ | |
1851 | type = get_canon_type (type, true, true); | |
1852 | if (!type) | |
1853 | return; | |
1854 | uid = TYPE_UID (type); | |
1855 | ||
1856 | if (bitmap_bit_p (been_there_done_that, uid)) | |
1857 | return; | |
1858 | bitmap_set_bit (been_there_done_that, uid); | |
1859 | ||
1860 | subtype_map = subtype_map_for_uid (uid, false); | |
1861 | ||
a4174ebf | 1862 | /* If we are doing a language with a type hierarchy, mark all of |
ea900239 DB |
1863 | the superclasses. */ |
1864 | if (TYPE_BINFO (type)) | |
1865 | for (binfo = TYPE_BINFO (type), i = 0; | |
1866 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
1867 | { | |
1868 | tree binfotype = BINFO_TYPE (base_binfo); | |
1869 | binfotype = mark_type (binfotype, FULL_ESCAPE); | |
1870 | close_type_full_escape (binfotype); | |
1871 | } | |
1872 | ||
1873 | /* Mark as escaped any types that have been down casted to | |
1874 | this type. */ | |
1875 | if (subtype_map) | |
1876 | EXECUTE_IF_SET_IN_BITMAP (subtype_map, 0, i, bi) | |
1877 | { | |
1878 | tree subtype = type_for_uid (i); | |
1879 | subtype = mark_type (subtype, FULL_ESCAPE); | |
1880 | close_type_full_escape (subtype); | |
1881 | } | |
1882 | ||
1883 | /* If the field is a struct or union type, mark all of the | |
1884 | subfields. */ | |
1885 | for (field = TYPE_FIELDS (type); | |
1886 | field; | |
1887 | field = TREE_CHAIN (field)) | |
1888 | { | |
1889 | tree field_type; | |
1890 | if (TREE_CODE (field) != FIELD_DECL) | |
1891 | continue; | |
1892 | ||
1893 | field_type = TREE_TYPE (field); | |
1894 | if (ipa_type_escape_star_count_of_interesting_or_array_type (field_type) >= 0) | |
1895 | { | |
1896 | field_type = mark_type (field_type, FULL_ESCAPE); | |
1897 | close_type_full_escape (field_type); | |
1898 | } | |
1899 | } | |
1900 | ||
1901 | /* For all of the types A that contain this type B and were part of | |
1902 | an expression like "&...A.B...", mark the A's as escaping. */ | |
1903 | address_result = splay_tree_lookup (uid_to_addressof_up_map, | |
1904 | (splay_tree_key) uid); | |
1905 | if (address_result) | |
1906 | { | |
1907 | bitmap containing_classes = (bitmap) address_result->value; | |
1908 | EXECUTE_IF_SET_IN_BITMAP (containing_classes, 0, i, bi) | |
1909 | { | |
1910 | close_type_full_escape (type_for_uid (i)); | |
1911 | } | |
1912 | } | |
1913 | } | |
1914 | ||
1915 | /* Transitively close the addressof bitmap for the type with UID. | |
569b7f6a | 1916 | This means that if we had a.b and b.c, a would have both b and c in |
ea900239 DB |
1917 | its maps. */ |
1918 | ||
1919 | static bitmap | |
1920 | close_addressof_down (int uid) | |
1921 | { | |
1922 | bitmap_iterator bi; | |
1923 | splay_tree_node result = | |
1924 | splay_tree_lookup (uid_to_addressof_down_map, (splay_tree_key) uid); | |
1925 | bitmap map = NULL; | |
1926 | bitmap new_map; | |
1927 | unsigned int i; | |
1928 | ||
1929 | if (result) | |
1930 | map = (bitmap) result->value; | |
1931 | else | |
1932 | return NULL; | |
1933 | ||
1934 | if (bitmap_bit_p (been_there_done_that, uid)) | |
1935 | return map; | |
1936 | bitmap_set_bit (been_there_done_that, uid); | |
1937 | ||
1938 | /* If the type escapes, get rid of the addressof map, it will not be | |
1939 | needed. */ | |
1940 | if (bitmap_bit_p (global_types_full_escape, uid)) | |
1941 | { | |
1942 | BITMAP_FREE (map); | |
1943 | splay_tree_remove (uid_to_addressof_down_map, (splay_tree_key) uid); | |
1944 | return NULL; | |
1945 | } | |
1946 | ||
1947 | /* The new_map will have all of the bits for the enclosed fields and | |
1948 | will have the unique id version of the old map. */ | |
1949 | new_map = BITMAP_ALLOC (&ipa_obstack); | |
1950 | ||
1951 | EXECUTE_IF_SET_IN_BITMAP (map, 0, i, bi) | |
1952 | { | |
1953 | bitmap submap = close_addressof_down (i); | |
1954 | bitmap_set_bit (new_map, i); | |
1955 | if (submap) | |
1956 | bitmap_ior_into (new_map, submap); | |
1957 | } | |
1958 | result->value = (splay_tree_value) new_map; | |
1959 | ||
1960 | BITMAP_FREE (map); | |
1961 | return new_map; | |
1962 | } | |
1963 | ||
1964 | \f | |
1965 | /* The main entry point for type escape analysis. */ | |
1966 | ||
c2924966 | 1967 | static unsigned int |
ea900239 DB |
1968 | type_escape_execute (void) |
1969 | { | |
1970 | struct cgraph_node *node; | |
8a4a83ed | 1971 | struct varpool_node *vnode; |
ea900239 DB |
1972 | unsigned int i; |
1973 | bitmap_iterator bi; | |
1974 | splay_tree_node result; | |
1975 | ||
1976 | ipa_init (); | |
1977 | ||
1978 | /* Process all of the variables first. */ | |
68e56cc4 | 1979 | FOR_EACH_STATIC_VARIABLE (vnode) |
ea900239 DB |
1980 | analyze_variable (vnode); |
1981 | ||
fa10beec | 1982 | /* Process all of the functions next. |
ea900239 DB |
1983 | |
1984 | We do not want to process any of the clones so we check that this | |
1985 | is a master clone. However, we do need to process any | |
1986 | AVAIL_OVERWRITABLE functions (these are never clones) because | |
1987 | they may cause a type variable to escape. | |
1988 | */ | |
1989 | for (node = cgraph_nodes; node; node = node->next) | |
144e8aac | 1990 | if (node->analyzed) |
ea900239 DB |
1991 | analyze_function (node); |
1992 | ||
1993 | ||
1994 | pointer_set_destroy (visited_nodes); | |
1995 | visited_nodes = NULL; | |
1996 | ||
1997 | /* Do all of the closures to discover which types escape the | |
1998 | compilation unit. */ | |
1999 | ||
2000 | been_there_done_that = BITMAP_ALLOC (&ipa_obstack); | |
2001 | bitmap_tmp = BITMAP_ALLOC (&ipa_obstack); | |
2002 | ||
2003 | /* Examine the types that we have directly seen in scanning the code | |
2004 | and add to that any contained types or superclasses. */ | |
2005 | ||
2006 | bitmap_copy (bitmap_tmp, global_types_seen); | |
2007 | EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi) | |
2008 | { | |
2009 | tree type = type_for_uid (i); | |
2010 | /* Only look at records and unions and pointer tos. */ | |
2011 | if (ipa_type_escape_star_count_of_interesting_or_array_type (type) >= 0) | |
2012 | close_type_seen (type); | |
2013 | } | |
2014 | bitmap_clear (been_there_done_that); | |
2015 | ||
2016 | /* Examine all of the types passed by value and mark any enclosed | |
2017 | pointer types as escaping. */ | |
2018 | bitmap_copy (bitmap_tmp, global_types_exposed_parameter); | |
2019 | EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi) | |
2020 | { | |
2021 | close_type_exposed_parameter (type_for_uid (i)); | |
2022 | } | |
2023 | bitmap_clear (been_there_done_that); | |
2024 | ||
2025 | /* Close the types for escape. If something escapes, then any | |
2026 | enclosed types escape as well as any subtypes. */ | |
2027 | bitmap_copy (bitmap_tmp, global_types_full_escape); | |
2028 | EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi) | |
2029 | { | |
2030 | close_type_full_escape (type_for_uid (i)); | |
2031 | } | |
2032 | bitmap_clear (been_there_done_that); | |
2033 | ||
2034 | /* Before this pass, the uid_to_addressof_down_map for type X | |
2035 | contained an entry for Y if there had been an operation of the | |
2036 | form &X.Y. This step adds all of the fields contained within Y | |
2037 | (recursively) to X's map. */ | |
2038 | ||
2039 | result = splay_tree_min (uid_to_addressof_down_map); | |
2040 | while (result) | |
2041 | { | |
2042 | int uid = result->key; | |
2043 | /* Close the addressof map, i.e. copy all of the transitive | |
2044 | substructures up to this level. */ | |
2045 | close_addressof_down (uid); | |
2046 | result = splay_tree_successor (uid_to_addressof_down_map, uid); | |
2047 | } | |
2048 | ||
2049 | /* Do not need the array types and pointer types in the persistent | |
2050 | data structures. */ | |
2051 | result = splay_tree_min (all_canon_types); | |
2052 | while (result) | |
2053 | { | |
2054 | tree type = (tree) result->value; | |
2055 | tree key = (tree) result->key; | |
2056 | if (POINTER_TYPE_P (type) | |
2057 | || TREE_CODE (type) == ARRAY_TYPE) | |
2058 | { | |
2059 | splay_tree_remove (all_canon_types, (splay_tree_key) result->key); | |
2060 | splay_tree_remove (type_to_canon_type, (splay_tree_key) type); | |
2061 | splay_tree_remove (uid_to_canon_type, (splay_tree_key) TYPE_UID (type)); | |
2062 | bitmap_clear_bit (global_types_seen, TYPE_UID (type)); | |
2063 | } | |
2064 | result = splay_tree_successor (all_canon_types, (splay_tree_key) key); | |
2065 | } | |
2066 | ||
ea900239 DB |
2067 | if (dump_file) |
2068 | { | |
2069 | EXECUTE_IF_SET_IN_BITMAP (global_types_seen, 0, i, bi) | |
2070 | { | |
2071 | /* The pointer types are in the global_types_full_escape | |
2072 | bitmap but not in the backwards map. They also contain | |
2073 | no useful information since they are not marked. */ | |
2074 | tree type = type_for_uid (i); | |
2075 | fprintf(dump_file, "type %d ", i); | |
2076 | print_generic_expr (dump_file, type, 0); | |
2077 | if (bitmap_bit_p (global_types_full_escape, i)) | |
2078 | fprintf(dump_file, " escaped\n"); | |
2079 | else | |
2080 | fprintf(dump_file, " contained\n"); | |
2081 | } | |
2082 | } | |
ea900239 DB |
2083 | |
2084 | /* Get rid of uid_to_addressof_up_map and its bitmaps. */ | |
2085 | result = splay_tree_min (uid_to_addressof_up_map); | |
2086 | while (result) | |
2087 | { | |
2088 | int uid = (int)result->key; | |
2089 | bitmap bm = (bitmap)result->value; | |
2090 | ||
2091 | BITMAP_FREE (bm); | |
2092 | splay_tree_remove (uid_to_addressof_up_map, (splay_tree_key) uid); | |
2093 | result = splay_tree_successor (uid_to_addressof_up_map, uid); | |
2094 | } | |
2095 | ||
2096 | /* Get rid of the subtype map. */ | |
2097 | result = splay_tree_min (uid_to_subtype_map); | |
2098 | while (result) | |
2099 | { | |
2100 | bitmap b = (bitmap)result->value; | |
2101 | BITMAP_FREE(b); | |
2102 | splay_tree_remove (uid_to_subtype_map, result->key); | |
2103 | result = splay_tree_min (uid_to_subtype_map); | |
2104 | } | |
2105 | splay_tree_delete (uid_to_subtype_map); | |
2106 | uid_to_subtype_map = NULL; | |
2107 | ||
2108 | BITMAP_FREE (global_types_exposed_parameter); | |
2109 | BITMAP_FREE (been_there_done_that); | |
2110 | BITMAP_FREE (bitmap_tmp); | |
c2924966 | 2111 | return 0; |
ea900239 DB |
2112 | } |
2113 | ||
2114 | static bool | |
2115 | gate_type_escape_vars (void) | |
2116 | { | |
7e8b322a | 2117 | return (flag_ipa_type_escape |
ea900239 DB |
2118 | /* Don't bother doing anything if the program has errors. */ |
2119 | && !(errorcount || sorrycount)); | |
2120 | } | |
2121 | ||
8ddbbcae | 2122 | struct simple_ipa_opt_pass pass_ipa_type_escape = |
ea900239 | 2123 | { |
8ddbbcae JH |
2124 | { |
2125 | SIMPLE_IPA_PASS, | |
ea900239 DB |
2126 | "type-escape-var", /* name */ |
2127 | gate_type_escape_vars, /* gate */ | |
2128 | type_escape_execute, /* execute */ | |
2129 | NULL, /* sub */ | |
2130 | NULL, /* next */ | |
2131 | 0, /* static_pass_number */ | |
2132 | TV_IPA_TYPE_ESCAPE, /* tv_id */ | |
2133 | 0, /* properties_required */ | |
2134 | 0, /* properties_provided */ | |
2135 | 0, /* properties_destroyed */ | |
2136 | 0, /* todo_flags_start */ | |
8ddbbcae JH |
2137 | 0 /* todo_flags_finish */ |
2138 | } | |
ea900239 | 2139 | }; |