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ea900239 | 1 | /* Type based alias analysis. |
71d59383 | 2 | Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc. |
ea900239 DB |
3 | Contributed by Kenneth Zadeck <zadeck@naturalbridge.com> |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 2, or (at your option) any later | |
10 | version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING. If not, write to the Free | |
783455db KH |
19 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
20 | 02110-1301, USA. */ | |
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" | |
46 | #include "ggc.h" | |
47 | #include "ipa-utils.h" | |
48 | #include "ipa-type-escape.h" | |
49 | #include "c-common.h" | |
50 | #include "tree-gimple.h" | |
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. */ | |
139 | static unsigned int look_for_casts (tree lhs ATTRIBUTE_UNUSED, tree); | |
140 | static bool is_cast_from_non_pointer (tree, tree, void *); | |
141 | ||
ea900239 DB |
142 | /* Get the name of TYPE or return the string "<UNNAMED>". */ |
143 | static char* | |
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. */ | |
150 | return (char*)"<UNNAMED>"; | |
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)) | |
160 | return (char*)IDENTIFIER_POINTER (DECL_NAME (name)); | |
161 | else | |
162 | /* Unnamed type, do what you like here. */ | |
163 | return (char*)"<UNNAMED>"; | |
164 | } | |
165 | else if (TREE_CODE (name) == IDENTIFIER_NODE) | |
166 | return (char*)IDENTIFIER_POINTER (name); | |
167 | else | |
168 | return (char*)"<UNNAMED>"; | |
169 | } | |
170 | ||
171 | struct type_brand_s | |
172 | { | |
173 | char* name; | |
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; | |
222 | if (lang_hooks.types_compatible_p (type, other_type) == 1) | |
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: | |
278 | case RECORD_TYPE: | |
279 | case UNION_TYPE: | |
280 | case VECTOR_TYPE: | |
281 | case VOID_TYPE: | |
282 | return true; | |
283 | ||
284 | default: | |
285 | return false; | |
286 | } | |
287 | } | |
288 | ||
289 | /* Get the canon type of TYPE. If SEE_THRU_PTRS is true, remove all | |
290 | the POINTER_TOs and if SEE_THRU_ARRAYS is true, remove all of the | |
291 | ARRAY_OFs and POINTER_TOs. */ | |
292 | ||
293 | static tree | |
294 | get_canon_type (tree type, bool see_thru_ptrs, bool see_thru_arrays) | |
295 | { | |
296 | splay_tree_node result; | |
297 | /* Strip the *'s off. */ | |
298 | if (!type || !type_to_consider (type)) | |
299 | return NULL; | |
300 | ||
301 | type = TYPE_MAIN_VARIANT (type); | |
302 | if (see_thru_arrays) | |
303 | while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE) | |
304 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
305 | ||
306 | else if (see_thru_ptrs) | |
307 | while (POINTER_TYPE_P (type)) | |
308 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
309 | ||
310 | result = splay_tree_lookup(type_to_canon_type, (splay_tree_key) type); | |
311 | ||
312 | if (result == NULL) | |
313 | return discover_unique_type (type); | |
314 | else return (tree) result->value; | |
315 | } | |
316 | ||
317 | /* Same as GET_CANON_TYPE, except return the TYPE_ID rather than the | |
318 | TYPE. */ | |
319 | ||
320 | static int | |
321 | get_canon_type_uid (tree type, bool see_thru_ptrs, bool see_thru_arrays) | |
322 | { | |
323 | type = get_canon_type (type, see_thru_ptrs, see_thru_arrays); | |
324 | if (type) | |
325 | return TYPE_UID(type); | |
326 | else return 0; | |
327 | } | |
328 | ||
329 | /* Return 0 if TYPE is a record or union type. Return a positive | |
330 | number if TYPE is a pointer to a record or union. The number is | |
331 | the number of pointer types stripped to get to the record or union | |
332 | type. Return -1 if TYPE is none of the above. */ | |
333 | ||
334 | int | |
335 | ipa_type_escape_star_count_of_interesting_type (tree type) | |
336 | { | |
337 | int count = 0; | |
338 | /* Strip the *'s off. */ | |
339 | if (!type) | |
340 | return -1; | |
341 | type = TYPE_MAIN_VARIANT (type); | |
342 | while (POINTER_TYPE_P (type)) | |
343 | { | |
344 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
345 | count++; | |
346 | } | |
347 | ||
348 | /* We are interested in records, and unions only. */ | |
349 | if (TREE_CODE (type) == RECORD_TYPE | |
350 | || TREE_CODE (type) == QUAL_UNION_TYPE | |
351 | || TREE_CODE (type) == UNION_TYPE) | |
352 | return count; | |
353 | else | |
354 | return -1; | |
355 | } | |
356 | ||
357 | ||
358 | /* Return 0 if TYPE is a record or union type. Return a positive | |
359 | number if TYPE is a pointer to a record or union. The number is | |
360 | the number of pointer types stripped to get to the record or union | |
361 | type. Return -1 if TYPE is none of the above. */ | |
362 | ||
363 | int | |
364 | ipa_type_escape_star_count_of_interesting_or_array_type (tree type) | |
365 | { | |
366 | int count = 0; | |
367 | /* Strip the *'s off. */ | |
368 | if (!type) | |
369 | return -1; | |
370 | type = TYPE_MAIN_VARIANT (type); | |
371 | while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE) | |
372 | { | |
373 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
374 | count++; | |
375 | } | |
376 | ||
377 | /* We are interested in records, and unions only. */ | |
378 | if (TREE_CODE (type) == RECORD_TYPE | |
379 | || TREE_CODE (type) == QUAL_UNION_TYPE | |
380 | || TREE_CODE (type) == UNION_TYPE) | |
381 | return count; | |
382 | else | |
383 | return -1; | |
384 | } | |
385 | ||
386 | ||
387 | /* Return true if the record, or union TYPE passed in escapes this | |
388 | compilation unit. Note that all of the pointer-to's are removed | |
389 | before testing since these may not be correct. */ | |
390 | ||
391 | bool | |
392 | ipa_type_escape_type_contained_p (tree type) | |
393 | { | |
394 | if (!initialized) | |
395 | return false; | |
396 | return !bitmap_bit_p (global_types_full_escape, | |
397 | get_canon_type_uid (type, true, false)); | |
398 | } | |
399 | ||
643519b7 | 400 | /* Return true if a modification to a field of type FIELD_TYPE cannot |
ea900239 DB |
401 | clobber a record of RECORD_TYPE. */ |
402 | ||
403 | bool | |
404 | ipa_type_escape_field_does_not_clobber_p (tree record_type, tree field_type) | |
405 | { | |
406 | splay_tree_node result; | |
407 | int uid; | |
408 | ||
409 | if (!initialized) | |
410 | return false; | |
411 | ||
412 | /* Strip off all of the pointer tos on the record type. Strip the | |
413 | same number of pointer tos from the field type. If the field | |
414 | type has fewer, it could not have been aliased. */ | |
415 | record_type = TYPE_MAIN_VARIANT (record_type); | |
416 | field_type = TYPE_MAIN_VARIANT (field_type); | |
417 | while (POINTER_TYPE_P (record_type)) | |
418 | { | |
419 | record_type = TYPE_MAIN_VARIANT (TREE_TYPE (record_type)); | |
420 | if (POINTER_TYPE_P (field_type)) | |
421 | field_type = TYPE_MAIN_VARIANT (TREE_TYPE (field_type)); | |
422 | else | |
423 | /* However, if field_type is a union, this quick test is not | |
424 | correct since one of the variants of the union may be a | |
425 | pointer to type and we cannot see across that here. So we | |
426 | just strip the remaining pointer tos off the record type | |
427 | and fall thru to the more precise code. */ | |
428 | if (TREE_CODE (field_type) == QUAL_UNION_TYPE | |
429 | || TREE_CODE (field_type) == UNION_TYPE) | |
430 | { | |
431 | while (POINTER_TYPE_P (record_type)) | |
432 | record_type = TYPE_MAIN_VARIANT (TREE_TYPE (record_type)); | |
433 | break; | |
434 | } | |
435 | else | |
436 | return true; | |
437 | } | |
438 | ||
439 | record_type = get_canon_type (record_type, true, true); | |
440 | /* The record type must be contained. The field type may | |
441 | escape. */ | |
442 | if (!ipa_type_escape_type_contained_p (record_type)) | |
443 | return false; | |
444 | ||
445 | uid = TYPE_UID (record_type); | |
446 | result = splay_tree_lookup (uid_to_addressof_down_map, (splay_tree_key) uid); | |
447 | ||
448 | if (result) | |
449 | { | |
450 | bitmap field_type_map = (bitmap) result->value; | |
451 | uid = get_canon_type_uid (field_type, true, true); | |
452 | /* If the bit is there, the address was taken. If not, it | |
453 | wasn't. */ | |
454 | return !bitmap_bit_p (field_type_map, uid); | |
455 | } | |
456 | else | |
457 | /* No bitmap means no addresses were taken. */ | |
458 | return true; | |
459 | } | |
460 | ||
461 | ||
462 | /* Add TYPE to the suspect type set. Return true if the bit needed to | |
463 | be marked. */ | |
464 | ||
465 | static tree | |
466 | mark_type (tree type, enum escape_t escape_status) | |
467 | { | |
468 | bitmap map = NULL; | |
469 | int uid; | |
470 | ||
471 | type = get_canon_type (type, true, true); | |
472 | if (!type) | |
473 | return NULL; | |
474 | ||
475 | switch (escape_status) | |
476 | { | |
477 | case EXPOSED_PARAMETER: | |
478 | map = global_types_exposed_parameter; | |
479 | break; | |
480 | case FULL_ESCAPE: | |
481 | map = global_types_full_escape; | |
482 | break; | |
483 | } | |
484 | ||
485 | uid = TYPE_UID (type); | |
486 | if (bitmap_bit_p (map, uid)) | |
487 | return type; | |
488 | else | |
489 | { | |
490 | bitmap_set_bit (map, uid); | |
491 | if (escape_status == FULL_ESCAPE) | |
492 | { | |
a4174ebf | 493 | /* Efficiency hack. When things are bad, do not mess around |
ea900239 DB |
494 | with this type anymore. */ |
495 | bitmap_set_bit (global_types_exposed_parameter, uid); | |
496 | } | |
497 | } | |
498 | return type; | |
499 | } | |
500 | ||
501 | /* Add interesting TYPE to the suspect type set. If the set is | |
502 | EXPOSED_PARAMETER and the TYPE is a pointer type, the set is | |
503 | changed to FULL_ESCAPE. */ | |
504 | ||
505 | static void | |
506 | mark_interesting_type (tree type, enum escape_t escape_status) | |
507 | { | |
508 | if (!type) return; | |
509 | if (ipa_type_escape_star_count_of_interesting_type (type) >= 0) | |
510 | { | |
511 | if ((escape_status == EXPOSED_PARAMETER) | |
512 | && POINTER_TYPE_P (type)) | |
513 | /* EXPOSED_PARAMETERs are only structs or unions are passed by | |
514 | value. Anything passed by reference to an external | |
515 | function fully exposes the type. */ | |
516 | mark_type (type, FULL_ESCAPE); | |
517 | else | |
518 | mark_type (type, escape_status); | |
519 | } | |
520 | } | |
521 | ||
522 | /* Return true if PARENT is supertype of CHILD. Both types must be | |
523 | known to be structures or unions. */ | |
524 | ||
525 | static bool | |
526 | parent_type_p (tree parent, tree child) | |
527 | { | |
528 | int i; | |
529 | tree binfo, base_binfo; | |
530 | if (TYPE_BINFO (parent)) | |
531 | for (binfo = TYPE_BINFO (parent), i = 0; | |
532 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
533 | { | |
534 | tree binfotype = BINFO_TYPE (base_binfo); | |
535 | if (binfotype == child) | |
536 | return true; | |
537 | else if (parent_type_p (binfotype, child)) | |
538 | return true; | |
539 | } | |
540 | if (TREE_CODE (parent) == UNION_TYPE | |
541 | || TREE_CODE (parent) == QUAL_UNION_TYPE) | |
542 | { | |
543 | tree field; | |
544 | /* Search all of the variants in the union to see if one of them | |
545 | is the child. */ | |
546 | for (field = TYPE_FIELDS (parent); | |
547 | field; | |
548 | field = TREE_CHAIN (field)) | |
549 | { | |
550 | tree field_type; | |
551 | if (TREE_CODE (field) != FIELD_DECL) | |
552 | continue; | |
553 | ||
554 | field_type = TREE_TYPE (field); | |
555 | if (field_type == child) | |
556 | return true; | |
557 | } | |
558 | ||
559 | /* If we did not find it, recursively ask the variants if one of | |
560 | their children is the child type. */ | |
561 | for (field = TYPE_FIELDS (parent); | |
562 | field; | |
563 | field = TREE_CHAIN (field)) | |
564 | { | |
565 | tree field_type; | |
566 | if (TREE_CODE (field) != FIELD_DECL) | |
567 | continue; | |
568 | ||
569 | field_type = TREE_TYPE (field); | |
570 | if (TREE_CODE (field_type) == RECORD_TYPE | |
571 | || TREE_CODE (field_type) == QUAL_UNION_TYPE | |
572 | || TREE_CODE (field_type) == UNION_TYPE) | |
573 | if (parent_type_p (field_type, child)) | |
574 | return true; | |
575 | } | |
576 | } | |
577 | ||
578 | if (TREE_CODE (parent) == RECORD_TYPE) | |
579 | { | |
580 | tree field; | |
581 | for (field = TYPE_FIELDS (parent); | |
582 | field; | |
583 | field = TREE_CHAIN (field)) | |
584 | { | |
585 | tree field_type; | |
586 | if (TREE_CODE (field) != FIELD_DECL) | |
587 | continue; | |
588 | ||
589 | field_type = TREE_TYPE (field); | |
590 | if (field_type == child) | |
591 | return true; | |
592 | /* You can only cast to the first field so if it does not | |
593 | match, quit. */ | |
594 | if (TREE_CODE (field_type) == RECORD_TYPE | |
595 | || TREE_CODE (field_type) == QUAL_UNION_TYPE | |
596 | || TREE_CODE (field_type) == UNION_TYPE) | |
597 | { | |
598 | if (parent_type_p (field_type, child)) | |
599 | return true; | |
600 | else | |
601 | break; | |
602 | } | |
603 | } | |
604 | } | |
605 | return false; | |
606 | } | |
607 | ||
608 | /* Return the number of pointer tos for TYPE and return TYPE with all | |
609 | of these stripped off. */ | |
610 | ||
611 | static int | |
612 | count_stars (tree* type_ptr) | |
613 | { | |
614 | tree type = *type_ptr; | |
615 | int i = 0; | |
616 | type = TYPE_MAIN_VARIANT (type); | |
617 | while (POINTER_TYPE_P (type)) | |
618 | { | |
619 | type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); | |
620 | i++; | |
621 | } | |
622 | ||
623 | *type_ptr = type; | |
624 | return i; | |
625 | } | |
626 | ||
627 | enum cast_type { | |
d4e70294 OG |
628 | CT_UP = 0x1, |
629 | CT_DOWN = 0x2, | |
630 | CT_SIDEWAYS = 0x4, | |
631 | CT_USELESS = 0x8, | |
632 | CT_FROM_P_BAD = 0x10, | |
633 | CT_FROM_NON_P = 0x20, | |
634 | CT_TO_NON_INTER = 0x40, | |
635 | CT_FROM_MALLOC = 0x80, | |
636 | CT_NO_CAST = 0x100 | |
ea900239 DB |
637 | }; |
638 | ||
639 | /* Check the cast FROM_TYPE to TO_TYPE. This function requires that | |
640 | the two types have already passed the | |
641 | ipa_type_escape_star_count_of_interesting_type test. */ | |
642 | ||
643 | static enum cast_type | |
644 | check_cast_type (tree to_type, tree from_type) | |
645 | { | |
646 | int to_stars = count_stars (&to_type); | |
647 | int from_stars = count_stars (&from_type); | |
648 | if (to_stars != from_stars) | |
649 | return CT_SIDEWAYS; | |
650 | ||
651 | if (to_type == from_type) | |
652 | return CT_USELESS; | |
653 | ||
654 | if (parent_type_p (to_type, from_type)) return CT_UP; | |
655 | if (parent_type_p (from_type, to_type)) return CT_DOWN; | |
656 | return CT_SIDEWAYS; | |
657 | } | |
658 | ||
110abdbc | 659 | /* This function returns nonzero if VAR is result of call |
d4e70294 OG |
660 | to malloc function. */ |
661 | ||
662 | static bool | |
663 | is_malloc_result (tree var) | |
664 | { | |
665 | tree def_stmt; | |
666 | tree rhs; | |
667 | int flags; | |
668 | ||
669 | if (!var) | |
670 | return false; | |
671 | ||
672 | if (SSA_NAME_IS_DEFAULT_DEF (var)) | |
673 | return false; | |
674 | ||
675 | def_stmt = SSA_NAME_DEF_STMT (var); | |
676 | ||
677 | if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT) | |
678 | return false; | |
679 | ||
680 | if (var != GIMPLE_STMT_OPERAND (def_stmt, 0)) | |
681 | return false; | |
682 | ||
683 | rhs = get_call_expr_in (def_stmt); | |
684 | ||
685 | if (!rhs) | |
686 | return false; | |
687 | ||
688 | flags = call_expr_flags (rhs); | |
689 | ||
690 | return ((flags & ECF_MALLOC) != 0); | |
691 | ||
692 | } | |
693 | ||
ea900239 | 694 | /* Check a cast FROM this variable, TO_TYPE. Mark the escaping types |
d4e70294 OG |
695 | if appropriate. Returns cast_type as detected. */ |
696 | ||
697 | static enum cast_type | |
ea900239 DB |
698 | check_cast (tree to_type, tree from) |
699 | { | |
700 | tree from_type = get_canon_type (TREE_TYPE (from), false, false); | |
701 | bool to_interesting_type, from_interesting_type; | |
d4e70294 | 702 | enum cast_type cast = CT_NO_CAST; |
ea900239 DB |
703 | |
704 | to_type = get_canon_type (to_type, false, false); | |
705 | if (!from_type || !to_type || from_type == to_type) | |
d4e70294 | 706 | return cast; |
ea900239 DB |
707 | |
708 | to_interesting_type = | |
709 | ipa_type_escape_star_count_of_interesting_type (to_type) >= 0; | |
710 | from_interesting_type = | |
711 | ipa_type_escape_star_count_of_interesting_type (from_type) >= 0; | |
712 | ||
713 | if (to_interesting_type) | |
714 | if (from_interesting_type) | |
715 | { | |
716 | /* Both types are interesting. This can be one of four types | |
717 | of cast: useless, up, down, or sideways. We do not care | |
718 | about up or useless. Sideways casts are always bad and | |
719 | both sides get marked as escaping. Downcasts are not | |
720 | interesting here because if type is marked as escaping, all | |
721 | of its subtypes escape. */ | |
d4e70294 OG |
722 | cast = check_cast_type (to_type, from_type); |
723 | switch (cast) | |
ea900239 DB |
724 | { |
725 | case CT_UP: | |
726 | case CT_USELESS: | |
727 | case CT_DOWN: | |
728 | break; | |
729 | ||
730 | case CT_SIDEWAYS: | |
731 | mark_type (to_type, FULL_ESCAPE); | |
732 | mark_type (from_type, FULL_ESCAPE); | |
733 | break; | |
d4e70294 OG |
734 | |
735 | default: | |
736 | break; | |
ea900239 DB |
737 | } |
738 | } | |
739 | else | |
740 | { | |
d4e70294 OG |
741 | /* This code excludes two cases from marking as escaped: |
742 | ||
743 | 1. if this is a cast of index of array of structures/unions | |
744 | that happens before accessing array element, we should not | |
745 | mark it as escaped. | |
746 | 2. if this is a cast from the local that is a result from a | |
747 | call to malloc, do not mark the cast as bad. | |
748 | ||
749 | */ | |
750 | ||
751 | if (POINTER_TYPE_P (to_type) && !POINTER_TYPE_P (from_type)) | |
752 | cast = CT_FROM_NON_P; | |
753 | else if (TREE_CODE (from) == SSA_NAME | |
754 | && is_malloc_result (from)) | |
755 | cast = CT_FROM_MALLOC; | |
756 | else | |
757 | { | |
758 | cast = CT_FROM_P_BAD; | |
759 | mark_type (to_type, FULL_ESCAPE); | |
760 | } | |
ea900239 DB |
761 | } |
762 | else if (from_interesting_type) | |
d4e70294 OG |
763 | { |
764 | mark_type (from_type, FULL_ESCAPE); | |
765 | cast = CT_TO_NON_INTER; | |
766 | } | |
767 | ||
768 | return cast; | |
769 | } | |
770 | ||
771 | typedef struct cast | |
772 | { | |
773 | int type; | |
774 | tree stmt; | |
775 | }cast_t; | |
776 | ||
777 | /* This function is a callback for walk_tree called from | |
778 | is_cast_from_non_pointer. The data->type is set to be: | |
779 | ||
780 | 0 - if there is no cast | |
781 | number - the number of casts from non-pointer type | |
782 | -1 - if there is a cast that makes the type to escape | |
783 | ||
784 | If data->type = number, then data->stmt will contain the | |
785 | last casting stmt met in traversing. */ | |
786 | ||
787 | static tree | |
788 | is_cast_from_non_pointer_1 (tree *tp, int *walk_subtrees, void *data) | |
789 | { | |
790 | tree def_stmt = *tp; | |
791 | ||
792 | ||
793 | if (pointer_set_insert (visited_stmts, def_stmt)) | |
794 | { | |
795 | *walk_subtrees = 0; | |
796 | return NULL; | |
797 | } | |
798 | ||
799 | switch (TREE_CODE (def_stmt)) | |
800 | { | |
801 | case GIMPLE_MODIFY_STMT: | |
802 | { | |
803 | use_operand_p use_p; | |
804 | ssa_op_iter iter; | |
805 | tree lhs = GIMPLE_STMT_OPERAND (def_stmt, 0); | |
806 | tree rhs = GIMPLE_STMT_OPERAND (def_stmt, 1); | |
807 | ||
808 | unsigned int cast = look_for_casts (lhs, rhs); | |
809 | /* Check that only one cast happened, and it's of | |
810 | non-pointer type. */ | |
811 | if ((cast & CT_FROM_NON_P) == (CT_FROM_NON_P) | |
812 | && (cast & ~(CT_FROM_NON_P)) == 0) | |
813 | { | |
814 | ((cast_t *)data)->stmt = def_stmt; | |
815 | ((cast_t *)data)->type++; | |
816 | ||
817 | FOR_EACH_SSA_USE_OPERAND (use_p, def_stmt, iter, SSA_OP_ALL_USES) | |
818 | { | |
819 | walk_use_def_chains (USE_FROM_PTR (use_p), is_cast_from_non_pointer, | |
820 | data, false); | |
821 | if (((cast_t*)data)->type == -1) | |
822 | return def_stmt; | |
823 | } | |
824 | } | |
825 | ||
826 | /* Check that there is no cast, or cast is not harmful. */ | |
827 | else if ((cast & CT_NO_CAST) == (CT_NO_CAST) | |
828 | || (cast & CT_DOWN) == (CT_DOWN) | |
829 | || (cast & CT_UP) == (CT_UP) | |
830 | || (cast & CT_USELESS) == (CT_USELESS) | |
831 | || (cast & CT_FROM_MALLOC) == (CT_FROM_MALLOC)) | |
832 | { | |
833 | FOR_EACH_SSA_USE_OPERAND (use_p, def_stmt, iter, SSA_OP_ALL_USES) | |
834 | { | |
835 | walk_use_def_chains (USE_FROM_PTR (use_p), is_cast_from_non_pointer, | |
836 | data, false); | |
837 | if (((cast_t*)data)->type == -1) | |
838 | return def_stmt; | |
839 | } | |
840 | } | |
841 | ||
842 | /* The cast is harmful. */ | |
843 | else | |
844 | { | |
845 | ((cast_t *)data)->type = -1; | |
846 | return def_stmt; | |
847 | } | |
848 | ||
849 | *walk_subtrees = 0; | |
850 | } | |
851 | break; | |
852 | ||
853 | default: | |
854 | { | |
855 | *walk_subtrees = 0; | |
856 | break; | |
857 | } | |
858 | } | |
859 | ||
860 | return NULL; | |
861 | } | |
862 | ||
863 | /* This function is a callback for walk_use_def_chains function called | |
864 | from is_array_access_through_pointer_and_index. */ | |
865 | ||
866 | static bool | |
867 | is_cast_from_non_pointer (tree var, tree def_stmt, void *data) | |
868 | { | |
869 | ||
870 | if (!def_stmt || !var) | |
871 | return false; | |
872 | ||
873 | if (TREE_CODE (def_stmt) == PHI_NODE) | |
874 | return false; | |
875 | ||
876 | if (SSA_NAME_IS_DEFAULT_DEF (var)) | |
877 | return false; | |
878 | ||
879 | walk_tree (&def_stmt, is_cast_from_non_pointer_1, data, NULL); | |
880 | if (((cast_t*)data)->type == -1) | |
881 | return true; | |
882 | ||
883 | return false; | |
884 | } | |
885 | ||
886 | /* When array element a_p[i] is accessed through the pointer a_p | |
887 | and index i, it's translated into the following sequence | |
888 | in gimple: | |
889 | ||
890 | i.1_5 = (unsigned int) i_1; | |
891 | D.1605_6 = i.1_5 * 16; | |
892 | D.1606_7 = (struct str_t *) D.1605_6; | |
893 | a_p.2_8 = a_p; | |
894 | D.1608_9 = D.1606_7 + a_p.2_8; | |
895 | ||
896 | OP0 and OP1 are of the same pointer types and stand for | |
897 | D.1606_7 and a_p.2_8 or vise versa. | |
898 | ||
899 | This function checks that: | |
900 | ||
901 | 1. one of OP0 and OP1 (D.1606_7) has passed only one cast from | |
902 | non-pointer type (D.1606_7 = (struct str_t *) D.1605_6;). | |
903 | ||
904 | 2. one of OP0 and OP1 which has passed the cast from | |
905 | non-pointer type (D.1606_7), is actually generated by multiplication of | |
906 | index by size of type to which both OP0 and OP1 point to | |
907 | (in this case D.1605_6 = i.1_5 * 16; ). | |
908 | ||
909 | 3. an address of def of the var to which was made cast (D.1605_6) | |
910 | was not taken.(How can it happen?) | |
911 | ||
912 | The following items are checked implicitly by the end of algorithm: | |
913 | ||
914 | 4. one of OP0 and OP1 (a_p.2_8) have never been cast | |
915 | (because if it was cast to pointer type, its type, that is also | |
916 | the type of OP0 and OP1, will be marked as escaped during | |
917 | analysis of casting stmt (when check_cast() is called | |
918 | from scan_for_refs for this stmt)). | |
919 | ||
920 | 5. defs of OP0 and OP1 are not passed into externally visible function | |
921 | (because if they are passed then their type, that is also the type of OP0 | |
922 | and OP1, will be marked and escaped during check_call function called from | |
923 | scan_for_refs with call stmt). | |
924 | ||
925 | In total, 1-5 guaranty that it's an access to array by pointer and index. | |
926 | ||
927 | */ | |
928 | ||
929 | static bool | |
930 | is_array_access_through_pointer_and_index (tree op0, tree op1) | |
931 | { | |
932 | tree base, offset, offset_cast_stmt; | |
933 | tree before_cast, before_cast_def_stmt; | |
934 | cast_t op0_cast, op1_cast; | |
935 | ||
936 | /* Check 1. */ | |
937 | ||
938 | /* Init data for walk_use_def_chains function. */ | |
939 | op0_cast.type = op1_cast.type = 0; | |
940 | op0_cast.stmt = op1_cast.stmt = NULL; | |
941 | ||
942 | visited_stmts = pointer_set_create (); | |
943 | walk_use_def_chains (op0, is_cast_from_non_pointer,(void *)(&op0_cast), false); | |
944 | pointer_set_destroy (visited_stmts); | |
945 | ||
946 | visited_stmts = pointer_set_create (); | |
947 | walk_use_def_chains (op1, is_cast_from_non_pointer,(void *)(&op1_cast), false); | |
948 | pointer_set_destroy (visited_stmts); | |
949 | ||
950 | if (op0_cast.type == 1 && op1_cast.type == 0) | |
951 | { | |
952 | base = op1; | |
953 | offset = op0; | |
954 | offset_cast_stmt = op0_cast.stmt; | |
955 | } | |
956 | else if (op0_cast.type == 0 && op1_cast.type == 1) | |
957 | { | |
958 | base = op0; | |
959 | offset = op1; | |
960 | offset_cast_stmt = op1_cast.stmt; | |
961 | } | |
962 | else | |
963 | return false; | |
964 | ||
965 | /* Check 2. | |
966 | offset_cast_stmt is of the form: | |
967 | D.1606_7 = (struct str_t *) D.1605_6; */ | |
968 | ||
969 | before_cast = SINGLE_SSA_TREE_OPERAND (offset_cast_stmt, SSA_OP_USE); | |
970 | if (!before_cast) | |
971 | return false; | |
972 | ||
973 | if (SSA_NAME_IS_DEFAULT_DEF(before_cast)) | |
974 | return false; | |
975 | ||
976 | before_cast_def_stmt = SSA_NAME_DEF_STMT (before_cast); | |
977 | if (!before_cast_def_stmt) | |
978 | return false; | |
979 | ||
980 | /* before_cast_def_stmt should be of the form: | |
981 | D.1605_6 = i.1_5 * 16; */ | |
982 | ||
983 | if (TREE_CODE (before_cast_def_stmt) == GIMPLE_MODIFY_STMT) | |
984 | { | |
985 | tree lhs = GIMPLE_STMT_OPERAND (before_cast_def_stmt,0); | |
986 | tree rhs = GIMPLE_STMT_OPERAND (before_cast_def_stmt,1); | |
987 | ||
988 | /* We expect temporary here. */ | |
989 | if (!is_gimple_reg (lhs)) | |
990 | return false; | |
991 | ||
992 | if (TREE_CODE (rhs) == MULT_EXPR) | |
993 | { | |
994 | tree arg0 = TREE_OPERAND (rhs, 0); | |
995 | tree arg1 = TREE_OPERAND (rhs, 1); | |
996 | tree unit_size = | |
997 | TYPE_SIZE_UNIT (TREE_TYPE (TYPE_MAIN_VARIANT (TREE_TYPE (op0)))); | |
998 | ||
999 | if (!(CONSTANT_CLASS_P (arg0) | |
1000 | && simple_cst_equal (arg0,unit_size)) | |
1001 | && !(CONSTANT_CLASS_P (arg1) | |
1002 | && simple_cst_equal (arg1,unit_size))) | |
1003 | return false; | |
1004 | } | |
1005 | else | |
1006 | return false; | |
1007 | } | |
1008 | else | |
1009 | return false; | |
1010 | ||
1011 | /* Check 3. | |
1012 | check that address of D.1605_6 was not taken. | |
1013 | FIXME: if D.1605_6 is gimple reg than it cannot be addressable. */ | |
1014 | ||
1015 | return true; | |
ea900239 DB |
1016 | } |
1017 | ||
1018 | /* Register the parameter and return types of function FN. The type | |
1019 | ESCAPES if the function is visible outside of the compilation | |
1020 | unit. */ | |
1021 | static void | |
1022 | check_function_parameter_and_return_types (tree fn, bool escapes) | |
1023 | { | |
1024 | tree arg; | |
1025 | ||
1026 | if (TYPE_ARG_TYPES (TREE_TYPE (fn))) | |
1027 | { | |
1028 | for (arg = TYPE_ARG_TYPES (TREE_TYPE (fn)); | |
1029 | arg && TREE_VALUE (arg) != void_type_node; | |
1030 | arg = TREE_CHAIN (arg)) | |
1031 | { | |
1032 | tree type = get_canon_type (TREE_VALUE (arg), false, false); | |
1033 | if (escapes) | |
1034 | mark_interesting_type (type, EXPOSED_PARAMETER); | |
1035 | } | |
1036 | } | |
1037 | else | |
1038 | { | |
1039 | /* FIXME - According to Geoff Keating, we should never have to | |
1040 | do this; the front ends should always process the arg list | |
1041 | from the TYPE_ARG_LIST. However, Geoff is wrong, this code | |
1042 | does seem to be live. */ | |
1043 | ||
1044 | for (arg = DECL_ARGUMENTS (fn); arg; arg = TREE_CHAIN (arg)) | |
1045 | { | |
1046 | tree type = get_canon_type (TREE_TYPE (arg), false, false); | |
1047 | if (escapes) | |
1048 | mark_interesting_type (type, EXPOSED_PARAMETER); | |
1049 | } | |
1050 | } | |
1051 | if (escapes) | |
1052 | { | |
1053 | tree type = get_canon_type (TREE_TYPE (TREE_TYPE (fn)), false, false); | |
1054 | mark_interesting_type (type, EXPOSED_PARAMETER); | |
1055 | } | |
1056 | } | |
1057 | ||
1058 | /* Return true if the variable T is the right kind of static variable to | |
1059 | perform compilation unit scope escape analysis. */ | |
1060 | ||
1061 | static inline void | |
1062 | has_proper_scope_for_analysis (tree t) | |
1063 | { | |
1064 | /* If the variable has the "used" attribute, treat it as if it had a | |
1065 | been touched by the devil. */ | |
1066 | tree type = get_canon_type (TREE_TYPE (t), false, false); | |
1067 | if (!type) return; | |
1068 | ||
1069 | if (lookup_attribute ("used", DECL_ATTRIBUTES (t))) | |
1070 | { | |
1071 | mark_interesting_type (type, FULL_ESCAPE); | |
1072 | return; | |
1073 | } | |
1074 | ||
1075 | /* Do not want to do anything with volatile except mark any | |
1076 | function that uses one to be not const or pure. */ | |
1077 | if (TREE_THIS_VOLATILE (t)) | |
1078 | return; | |
1079 | ||
1080 | /* Do not care about a local automatic that is not static. */ | |
1081 | if (!TREE_STATIC (t) && !DECL_EXTERNAL (t)) | |
1082 | return; | |
1083 | ||
1084 | if (DECL_EXTERNAL (t) || TREE_PUBLIC (t)) | |
1085 | { | |
1086 | /* If the front end set the variable to be READONLY and | |
1087 | constant, we can allow this variable in pure or const | |
1088 | functions but the scope is too large for our analysis to set | |
1089 | these bits ourselves. */ | |
1090 | ||
1091 | if (TREE_READONLY (t) | |
1092 | && DECL_INITIAL (t) | |
1093 | && is_gimple_min_invariant (DECL_INITIAL (t))) | |
1094 | ; /* Read of a constant, do not change the function state. */ | |
1095 | else | |
1096 | { | |
1097 | /* The type escapes for all public and externs. */ | |
1098 | mark_interesting_type (type, FULL_ESCAPE); | |
1099 | } | |
1100 | } | |
1101 | } | |
1102 | ||
1103 | /* If T is a VAR_DECL for a static that we are interested in, add the | |
1104 | uid to the bitmap. */ | |
1105 | ||
1106 | static void | |
1107 | check_operand (tree t) | |
1108 | { | |
1109 | if (!t) return; | |
1110 | ||
1111 | /* This is an assignment from a function, register the types as | |
1112 | escaping. */ | |
1113 | if (TREE_CODE (t) == FUNCTION_DECL) | |
1114 | check_function_parameter_and_return_types (t, true); | |
1115 | ||
1116 | else if (TREE_CODE (t) == VAR_DECL) | |
1117 | has_proper_scope_for_analysis (t); | |
1118 | } | |
1119 | ||
1120 | /* Examine tree T for references. */ | |
1121 | ||
1122 | static void | |
1123 | check_tree (tree t) | |
1124 | { | |
1125 | if ((TREE_CODE (t) == EXC_PTR_EXPR) || (TREE_CODE (t) == FILTER_EXPR)) | |
1126 | return; | |
1127 | ||
d4e70294 OG |
1128 | /* We want to catch here also REALPART_EXPR and IMAGEPART_EXPR, |
1129 | but they already included in handled_component_p. */ | |
1130 | while (handled_component_p (t)) | |
ea900239 DB |
1131 | { |
1132 | if (TREE_CODE (t) == ARRAY_REF) | |
1133 | check_operand (TREE_OPERAND (t, 1)); | |
1134 | t = TREE_OPERAND (t, 0); | |
1135 | } | |
1136 | ||
1137 | if (INDIRECT_REF_P (t)) | |
1138 | /* || TREE_CODE (t) == MEM_REF) */ | |
1139 | check_tree (TREE_OPERAND (t, 0)); | |
1140 | ||
1141 | if (SSA_VAR_P (t) || (TREE_CODE (t) == FUNCTION_DECL)) | |
1142 | check_operand (t); | |
1143 | } | |
1144 | ||
1145 | /* Create an address_of edge FROM_TYPE.TO_TYPE. */ | |
1146 | static void | |
1147 | mark_interesting_addressof (tree to_type, tree from_type) | |
1148 | { | |
1149 | int from_uid; | |
1150 | int to_uid; | |
1151 | bitmap type_map; | |
1152 | splay_tree_node result; | |
1153 | ||
1154 | from_type = get_canon_type (from_type, false, false); | |
1155 | to_type = get_canon_type (to_type, false, false); | |
1156 | ||
1157 | if (!from_type || !to_type) | |
1158 | return; | |
1159 | ||
1160 | from_uid = TYPE_UID (from_type); | |
1161 | to_uid = TYPE_UID (to_type); | |
1162 | ||
1163 | gcc_assert (ipa_type_escape_star_count_of_interesting_type (from_type) == 0); | |
1164 | ||
1165 | /* Process the Y into X map pointer. */ | |
1166 | result = splay_tree_lookup (uid_to_addressof_down_map, | |
1167 | (splay_tree_key) from_uid); | |
1168 | ||
1169 | if (result) | |
1170 | type_map = (bitmap) result->value; | |
1171 | else | |
1172 | { | |
1173 | type_map = BITMAP_ALLOC (&ipa_obstack); | |
1174 | splay_tree_insert (uid_to_addressof_down_map, | |
1175 | from_uid, | |
1176 | (splay_tree_value)type_map); | |
1177 | } | |
1178 | bitmap_set_bit (type_map, TYPE_UID (to_type)); | |
1179 | ||
1180 | /* Process the X into Y reverse map pointer. */ | |
1181 | result = | |
1182 | splay_tree_lookup (uid_to_addressof_up_map, (splay_tree_key) to_uid); | |
1183 | ||
1184 | if (result) | |
1185 | type_map = (bitmap) result->value; | |
1186 | else | |
1187 | { | |
1188 | type_map = BITMAP_ALLOC (&ipa_obstack); | |
1189 | splay_tree_insert (uid_to_addressof_up_map, | |
1190 | to_uid, | |
1191 | (splay_tree_value)type_map); | |
1192 | } | |
d4e70294 | 1193 | bitmap_set_bit (type_map, TYPE_UID (from_type)); |
ea900239 DB |
1194 | } |
1195 | ||
1196 | /* Scan tree T to see if there are any addresses taken in within T. */ | |
1197 | ||
1198 | static void | |
1199 | look_for_address_of (tree t) | |
1200 | { | |
1201 | if (TREE_CODE (t) == ADDR_EXPR) | |
1202 | { | |
1203 | tree x = get_base_var (t); | |
1204 | tree cref = TREE_OPERAND (t, 0); | |
1205 | ||
1206 | /* If we have an expression of the form "&a.b.c.d", mark a.b, | |
1207 | b.c and c.d. as having its address taken. */ | |
1208 | tree fielddecl = NULL_TREE; | |
1209 | while (cref!= x) | |
1210 | { | |
1211 | if (TREE_CODE (cref) == COMPONENT_REF) | |
1212 | { | |
1213 | fielddecl = TREE_OPERAND (cref, 1); | |
1214 | mark_interesting_addressof (TREE_TYPE (fielddecl), | |
1215 | DECL_FIELD_CONTEXT (fielddecl)); | |
1216 | } | |
1217 | else if (TREE_CODE (cref) == ARRAY_REF) | |
1218 | get_canon_type (TREE_TYPE (cref), false, false); | |
1219 | ||
1220 | cref = TREE_OPERAND (cref, 0); | |
1221 | } | |
1222 | ||
1223 | if (TREE_CODE (x) == VAR_DECL) | |
1224 | has_proper_scope_for_analysis (x); | |
1225 | } | |
1226 | } | |
1227 | ||
1228 | ||
1229 | /* Scan tree T to see if there are any casts within it. | |
1230 | LHS Is the LHS of the expression involving the cast. */ | |
1231 | ||
d4e70294 OG |
1232 | static unsigned int |
1233 | look_for_casts (tree lhs ATTRIBUTE_UNUSED, tree t) | |
ea900239 | 1234 | { |
d4e70294 OG |
1235 | unsigned int cast = 0; |
1236 | ||
1237 | ||
ea900239 DB |
1238 | if (is_gimple_cast (t) || TREE_CODE (t) == VIEW_CONVERT_EXPR) |
1239 | { | |
1240 | tree castfromvar = TREE_OPERAND (t, 0); | |
d4e70294 | 1241 | cast = cast | check_cast (TREE_TYPE (t), castfromvar); |
ea900239 | 1242 | } |
44d974b5 OG |
1243 | else |
1244 | while (handled_component_p (t)) | |
1245 | { | |
1246 | t = TREE_OPERAND (t, 0); | |
1247 | if (TREE_CODE (t) == VIEW_CONVERT_EXPR) | |
1248 | { | |
1249 | /* This may be some part of a component ref. | |
1250 | IE it may be a.b.VIEW_CONVERT_EXPR<weird_type>(c).d, AFAIK. | |
1251 | castfromref will give you a.b.c, not a. */ | |
1252 | tree castfromref = TREE_OPERAND (t, 0); | |
1253 | cast = cast | check_cast (TREE_TYPE (t), castfromref); | |
1254 | } | |
1255 | else if (TREE_CODE (t) == COMPONENT_REF) | |
1256 | get_canon_type (TREE_TYPE (TREE_OPERAND (t, 1)), false, false); | |
1257 | } | |
d4e70294 OG |
1258 | |
1259 | if (!cast) | |
1260 | cast = CT_NO_CAST; | |
1261 | return cast; | |
ea900239 DB |
1262 | } |
1263 | ||
1264 | /* Check to see if T is a read or address of operation on a static var | |
1265 | we are interested in analyzing. */ | |
1266 | ||
1267 | static void | |
1268 | check_rhs_var (tree t) | |
1269 | { | |
1270 | look_for_address_of (t); | |
1271 | check_tree(t); | |
1272 | } | |
1273 | ||
1274 | /* Check to see if T is an assignment to a static var we are | |
1275 | interested in analyzing. */ | |
1276 | ||
1277 | static void | |
1278 | check_lhs_var (tree t) | |
1279 | { | |
1280 | check_tree(t); | |
1281 | } | |
1282 | ||
1283 | /* This is a scaled down version of get_asm_expr_operands from | |
1284 | tree_ssa_operands.c. The version there runs much later and assumes | |
1285 | that aliasing information is already available. Here we are just | |
1286 | trying to find if the set of inputs and outputs contain references | |
1287 | or address of operations to local. FN is the function being | |
1288 | analyzed and STMT is the actual asm statement. */ | |
1289 | ||
1290 | static void | |
1291 | get_asm_expr_operands (tree stmt) | |
1292 | { | |
1293 | int noutputs = list_length (ASM_OUTPUTS (stmt)); | |
1294 | const char **oconstraints | |
1295 | = (const char **) alloca ((noutputs) * sizeof (const char *)); | |
1296 | int i; | |
1297 | tree link; | |
1298 | const char *constraint; | |
1299 | bool allows_mem, allows_reg, is_inout; | |
1300 | ||
1301 | for (i=0, link = ASM_OUTPUTS (stmt); link; ++i, link = TREE_CHAIN (link)) | |
1302 | { | |
1303 | oconstraints[i] = constraint | |
1304 | = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link))); | |
1305 | parse_output_constraint (&constraint, i, 0, 0, | |
1306 | &allows_mem, &allows_reg, &is_inout); | |
1307 | ||
1308 | check_lhs_var (TREE_VALUE (link)); | |
1309 | } | |
1310 | ||
1311 | for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link)) | |
1312 | { | |
1313 | constraint | |
1314 | = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link))); | |
1315 | parse_input_constraint (&constraint, 0, 0, noutputs, 0, | |
1316 | oconstraints, &allows_mem, &allows_reg); | |
1317 | ||
1318 | check_rhs_var (TREE_VALUE (link)); | |
1319 | } | |
1320 | ||
1321 | /* There is no code here to check for asm memory clobbers. The | |
1322 | casual maintainer might think that such code would be necessary, | |
1323 | but that appears to be wrong. In other parts of the compiler, | |
1324 | the asm memory clobbers are assumed to only clobber variables | |
1325 | that are addressable. All types with addressable instances are | |
1326 | assumed to already escape. So, we are protected here. */ | |
1327 | } | |
1328 | ||
1329 | /* Check the parameters of a function call to CALL_EXPR to mark the | |
1330 | types that pass across the function boundary. Also check to see if | |
1331 | this is either an indirect call, a call outside the compilation | |
1332 | unit. */ | |
1333 | ||
d4e70294 | 1334 | static void |
ea900239 DB |
1335 | check_call (tree call_expr) |
1336 | { | |
ea900239 DB |
1337 | tree operand; |
1338 | tree callee_t = get_callee_fndecl (call_expr); | |
ea900239 DB |
1339 | struct cgraph_node* callee; |
1340 | enum availability avail = AVAIL_NOT_AVAILABLE; | |
5039610b | 1341 | call_expr_arg_iterator iter; |
ea900239 | 1342 | |
5039610b SL |
1343 | FOR_EACH_CALL_EXPR_ARG (operand, iter, call_expr) |
1344 | check_rhs_var (operand); | |
ea900239 DB |
1345 | |
1346 | if (callee_t) | |
1347 | { | |
1348 | tree arg_type; | |
1349 | tree last_arg_type = NULL; | |
1350 | callee = cgraph_node(callee_t); | |
1351 | avail = cgraph_function_body_availability (callee); | |
1352 | ||
1353 | /* Check that there are no implicit casts in the passing of | |
1354 | parameters. */ | |
1355 | if (TYPE_ARG_TYPES (TREE_TYPE (callee_t))) | |
1356 | { | |
5039610b SL |
1357 | for (arg_type = TYPE_ARG_TYPES (TREE_TYPE (callee_t)), |
1358 | operand = first_call_expr_arg (call_expr, &iter); | |
ea900239 | 1359 | arg_type && TREE_VALUE (arg_type) != void_type_node; |
5039610b SL |
1360 | arg_type = TREE_CHAIN (arg_type), |
1361 | operand = next_call_expr_arg (&iter)) | |
ea900239 DB |
1362 | { |
1363 | if (operand) | |
1364 | { | |
ea900239 | 1365 | last_arg_type = TREE_VALUE(arg_type); |
5039610b | 1366 | check_cast (last_arg_type, operand); |
ea900239 DB |
1367 | } |
1368 | else | |
1369 | /* The code reaches here for some unfortunate | |
1370 | builtin functions that do not have a list of | |
1371 | argument types. */ | |
1372 | break; | |
1373 | } | |
1374 | } | |
1375 | else | |
1376 | { | |
1377 | /* FIXME - According to Geoff Keating, we should never | |
1378 | have to do this; the front ends should always process | |
1379 | the arg list from the TYPE_ARG_LIST. */ | |
5039610b SL |
1380 | for (arg_type = DECL_ARGUMENTS (callee_t), |
1381 | operand = first_call_expr_arg (call_expr, &iter); | |
ea900239 | 1382 | arg_type; |
5039610b SL |
1383 | arg_type = TREE_CHAIN (arg_type), |
1384 | operand = next_call_expr_arg (&iter)) | |
ea900239 DB |
1385 | { |
1386 | if (operand) | |
1387 | { | |
ea900239 | 1388 | last_arg_type = TREE_TYPE(arg_type); |
5039610b | 1389 | check_cast (last_arg_type, operand); |
ea900239 DB |
1390 | } |
1391 | else | |
1392 | /* The code reaches here for some unfortunate | |
1393 | builtin functions that do not have a list of | |
1394 | argument types. */ | |
1395 | break; | |
1396 | } | |
1397 | } | |
1398 | ||
1399 | /* In the case where we have a var_args function, we need to | |
1400 | check the remaining parameters against the last argument. */ | |
1401 | arg_type = last_arg_type; | |
1402 | for (; | |
1403 | operand != NULL_TREE; | |
5039610b | 1404 | operand = next_call_expr_arg (&iter)) |
ea900239 | 1405 | { |
ea900239 | 1406 | if (arg_type) |
5039610b | 1407 | check_cast (arg_type, operand); |
ea900239 DB |
1408 | else |
1409 | { | |
1410 | /* The code reaches here for some unfortunate | |
1411 | builtin functions that do not have a list of | |
1412 | argument types. Most of these functions have | |
1413 | been marked as having their parameters not | |
1414 | escape, but for the rest, the type is doomed. */ | |
5039610b | 1415 | tree type = get_canon_type (TREE_TYPE (operand), false, false); |
ea900239 DB |
1416 | mark_interesting_type (type, FULL_ESCAPE); |
1417 | } | |
1418 | } | |
1419 | } | |
1420 | ||
1421 | /* The callee is either unknown (indirect call) or there is just no | |
1422 | scannable code for it (external call) . We look to see if there | |
1423 | are any bits available for the callee (such as by declaration or | |
1424 | because it is builtin) and process solely on the basis of those | |
1425 | bits. */ | |
1426 | ||
1427 | if (avail == AVAIL_NOT_AVAILABLE || avail == AVAIL_OVERWRITABLE) | |
1428 | { | |
1429 | /* If this is a direct call to an external function, mark all of | |
1430 | the parameter and return types. */ | |
5039610b | 1431 | FOR_EACH_CALL_EXPR_ARG (operand, iter, call_expr) |
ea900239 | 1432 | { |
5039610b | 1433 | tree type = get_canon_type (TREE_TYPE (operand), false, false); |
ea900239 DB |
1434 | mark_interesting_type (type, EXPOSED_PARAMETER); |
1435 | } | |
1436 | ||
1437 | if (callee_t) | |
1438 | { | |
1439 | tree type = | |
1440 | get_canon_type (TREE_TYPE (TREE_TYPE (callee_t)), false, false); | |
1441 | mark_interesting_type (type, EXPOSED_PARAMETER); | |
1442 | } | |
1443 | } | |
ea900239 DB |
1444 | } |
1445 | ||
1446 | /* CODE is the operation on OP0 and OP1. OP0 is the operand that we | |
1447 | *know* is a pointer type. OP1 may be a pointer type. */ | |
1448 | static bool | |
1449 | okay_pointer_operation (enum tree_code code, tree op0, tree op1) | |
1450 | { | |
1451 | tree op0type = TYPE_MAIN_VARIANT (TREE_TYPE (op0)); | |
1452 | tree op1type = TYPE_MAIN_VARIANT (TREE_TYPE (op1)); | |
d4e70294 | 1453 | |
ea900239 DB |
1454 | switch (code) |
1455 | { | |
1456 | case MULT_EXPR: | |
d4e70294 OG |
1457 | /* Multiplication does not change alignment. */ |
1458 | return true; | |
1459 | break; | |
ea900239 | 1460 | case MINUS_EXPR: |
d4e70294 OG |
1461 | case PLUS_EXPR: |
1462 | { | |
1463 | if (POINTER_TYPE_P (op1type) | |
1464 | && TREE_CODE (op0) == SSA_NAME | |
1465 | && TREE_CODE (op1) == SSA_NAME | |
1466 | && is_array_access_through_pointer_and_index (op0, op1)) | |
1467 | return true; | |
1468 | else | |
1469 | { | |
1470 | tree size_of_op0_points_to = TYPE_SIZE_UNIT (TREE_TYPE (op0type)); | |
1471 | ||
1472 | if (CONSTANT_CLASS_P (op1) | |
1473 | && size_of_op0_points_to | |
1474 | && multiple_of_p (TREE_TYPE (size_of_op0_points_to), | |
1475 | op1, size_of_op0_points_to)) | |
1476 | return true; | |
ea900239 | 1477 | |
d4e70294 OG |
1478 | if (CONSTANT_CLASS_P (op0) |
1479 | && size_of_op0_points_to | |
1480 | && multiple_of_p (TREE_TYPE (size_of_op0_points_to), | |
1481 | op0, size_of_op0_points_to)) | |
1482 | return true; | |
1483 | } | |
1484 | } | |
1485 | break; | |
ea900239 DB |
1486 | default: |
1487 | return false; | |
1488 | } | |
1489 | return false; | |
1490 | } | |
1491 | ||
1492 | /* TP is the part of the tree currently under the microscope. | |
1493 | WALK_SUBTREES is part of the walk_tree api but is unused here. | |
1494 | DATA is cgraph_node of the function being walked. */ | |
1495 | ||
1496 | /* FIXME: When this is converted to run over SSA form, this code | |
1497 | should be converted to use the operand scanner. */ | |
1498 | ||
1499 | static tree | |
1500 | scan_for_refs (tree *tp, int *walk_subtrees, void *data) | |
1501 | { | |
c5274326 | 1502 | struct cgraph_node *fn = (struct cgraph_node *) data; |
ea900239 DB |
1503 | tree t = *tp; |
1504 | ||
1505 | switch (TREE_CODE (t)) | |
1506 | { | |
1507 | case VAR_DECL: | |
1508 | if (DECL_INITIAL (t)) | |
1509 | walk_tree (&DECL_INITIAL (t), scan_for_refs, fn, visited_nodes); | |
1510 | *walk_subtrees = 0; | |
1511 | break; | |
1512 | ||
07beea0d | 1513 | case GIMPLE_MODIFY_STMT: |
ea900239 DB |
1514 | { |
1515 | /* First look on the lhs and see what variable is stored to */ | |
07beea0d AH |
1516 | tree lhs = GIMPLE_STMT_OPERAND (t, 0); |
1517 | tree rhs = GIMPLE_STMT_OPERAND (t, 1); | |
ea900239 DB |
1518 | |
1519 | check_lhs_var (lhs); | |
1520 | check_cast (TREE_TYPE (lhs), rhs); | |
1521 | ||
1522 | /* For the purposes of figuring out what the cast affects */ | |
1523 | ||
1524 | /* Next check the operands on the rhs to see if they are ok. */ | |
1525 | switch (TREE_CODE_CLASS (TREE_CODE (rhs))) | |
1526 | { | |
1527 | case tcc_binary: | |
1528 | { | |
1529 | tree op0 = TREE_OPERAND (rhs, 0); | |
1530 | tree type0 = get_canon_type (TREE_TYPE (op0), false, false); | |
1531 | tree op1 = TREE_OPERAND (rhs, 1); | |
1532 | tree type1 = get_canon_type (TREE_TYPE (op1), false, false); | |
1533 | ||
1534 | /* If this is pointer arithmetic of any bad sort, then | |
1535 | we need to mark the types as bad. For binary | |
1536 | operations, no binary operator we currently support | |
1537 | is always "safe" in regard to what it would do to | |
1538 | pointers for purposes of determining which types | |
1539 | escape, except operations of the size of the type. | |
1540 | It is possible that min and max under the right set | |
1541 | of circumstances and if the moon is in the correct | |
1542 | place could be safe, but it is hard to see how this | |
1543 | is worth the effort. */ | |
1544 | ||
1545 | if (type0 && POINTER_TYPE_P (type0) | |
1546 | && !okay_pointer_operation (TREE_CODE (rhs), op0, op1)) | |
1547 | mark_interesting_type (type0, FULL_ESCAPE); | |
1548 | if (type1 && POINTER_TYPE_P (type1) | |
1549 | && !okay_pointer_operation (TREE_CODE (rhs), op1, op0)) | |
1550 | mark_interesting_type (type1, FULL_ESCAPE); | |
1551 | ||
1552 | look_for_casts (lhs, op0); | |
1553 | look_for_casts (lhs, op1); | |
1554 | check_rhs_var (op0); | |
1555 | check_rhs_var (op1); | |
1556 | } | |
1557 | break; | |
1558 | case tcc_unary: | |
1559 | { | |
1560 | tree op0 = TREE_OPERAND (rhs, 0); | |
1561 | tree type0 = get_canon_type (TREE_TYPE (op0), false, false); | |
1562 | /* For unary operations, if the operation is NEGATE or | |
1563 | ABS on a pointer, this is also considered pointer | |
1564 | arithmetic and thus, bad for business. */ | |
1565 | if (type0 && (TREE_CODE (op0) == NEGATE_EXPR | |
1566 | || TREE_CODE (op0) == ABS_EXPR) | |
1567 | && POINTER_TYPE_P (type0)) | |
1568 | { | |
1569 | mark_interesting_type (type0, FULL_ESCAPE); | |
1570 | } | |
1571 | check_rhs_var (op0); | |
1572 | look_for_casts (lhs, op0); | |
1573 | look_for_casts (lhs, rhs); | |
1574 | } | |
1575 | ||
1576 | break; | |
1577 | case tcc_reference: | |
1578 | look_for_casts (lhs, rhs); | |
1579 | check_rhs_var (rhs); | |
1580 | break; | |
1581 | case tcc_declaration: | |
1582 | check_rhs_var (rhs); | |
1583 | break; | |
1584 | case tcc_expression: | |
1585 | switch (TREE_CODE (rhs)) | |
1586 | { | |
1587 | case ADDR_EXPR: | |
1588 | look_for_casts (lhs, TREE_OPERAND (rhs, 0)); | |
1589 | check_rhs_var (rhs); | |
1590 | break; | |
5039610b SL |
1591 | default: |
1592 | break; | |
1593 | } | |
1594 | break; | |
1595 | case tcc_vl_exp: | |
1596 | switch (TREE_CODE (rhs)) | |
1597 | { | |
1598 | case CALL_EXPR: | |
ea900239 DB |
1599 | /* If this is a call to malloc, squirrel away the |
1600 | result so we do mark the resulting cast as being | |
1601 | bad. */ | |
d4e70294 | 1602 | check_call (rhs); |
ea900239 DB |
1603 | break; |
1604 | default: | |
1605 | break; | |
1606 | } | |
1607 | break; | |
1608 | default: | |
1609 | break; | |
1610 | } | |
1611 | *walk_subtrees = 0; | |
1612 | } | |
1613 | break; | |
1614 | ||
1615 | case ADDR_EXPR: | |
1616 | /* This case is here to find addresses on rhs of constructors in | |
1617 | decl_initial of static variables. */ | |
1618 | check_rhs_var (t); | |
1619 | *walk_subtrees = 0; | |
1620 | break; | |
1621 | ||
1622 | case CALL_EXPR: | |
1623 | check_call (t); | |
1624 | *walk_subtrees = 0; | |
1625 | break; | |
1626 | ||
1627 | case ASM_EXPR: | |
1628 | get_asm_expr_operands (t); | |
1629 | *walk_subtrees = 0; | |
1630 | break; | |
1631 | ||
1632 | default: | |
1633 | break; | |
1634 | } | |
1635 | return NULL; | |
1636 | } | |
1637 | ||
1638 | ||
1639 | /* The init routine for analyzing global static variable usage. See | |
1640 | comments at top for description. */ | |
1641 | static void | |
1642 | ipa_init (void) | |
1643 | { | |
1644 | bitmap_obstack_initialize (&ipa_obstack); | |
1645 | global_types_exposed_parameter = BITMAP_ALLOC (&ipa_obstack); | |
1646 | global_types_full_escape = BITMAP_ALLOC (&ipa_obstack); | |
1647 | global_types_seen = BITMAP_ALLOC (&ipa_obstack); | |
ea900239 DB |
1648 | |
1649 | uid_to_canon_type = splay_tree_new (splay_tree_compare_ints, 0, 0); | |
1650 | all_canon_types = splay_tree_new (compare_type_brand, 0, 0); | |
1651 | type_to_canon_type = splay_tree_new (splay_tree_compare_pointers, 0, 0); | |
1652 | uid_to_subtype_map = splay_tree_new (splay_tree_compare_ints, 0, 0); | |
1653 | uid_to_addressof_down_map = splay_tree_new (splay_tree_compare_ints, 0, 0); | |
1654 | uid_to_addressof_up_map = splay_tree_new (splay_tree_compare_ints, 0, 0); | |
1655 | ||
1656 | /* There are some shared nodes, in particular the initializers on | |
1657 | static declarations. We do not need to scan them more than once | |
1658 | since all we would be interested in are the addressof | |
1659 | operations. */ | |
1660 | visited_nodes = pointer_set_create (); | |
1661 | initialized = true; | |
1662 | } | |
1663 | ||
1664 | /* Check out the rhs of a static or global initialization VNODE to see | |
1665 | if any of them contain addressof operations. Note that some of | |
6738920f | 1666 | these variables may not even be referenced in the code in this |
ea900239 DB |
1667 | compilation unit but their right hand sides may contain references |
1668 | to variables defined within this unit. */ | |
1669 | ||
1670 | static void | |
8a4a83ed | 1671 | analyze_variable (struct varpool_node *vnode) |
ea900239 DB |
1672 | { |
1673 | tree global = vnode->decl; | |
1674 | tree type = get_canon_type (TREE_TYPE (global), false, false); | |
1675 | ||
1676 | /* If this variable has exposure beyond the compilation unit, add | |
1677 | its type to the global types. */ | |
1678 | ||
1679 | if (vnode->externally_visible) | |
1680 | mark_interesting_type (type, FULL_ESCAPE); | |
1681 | ||
dd2c9f74 VR |
1682 | gcc_assert (TREE_CODE (global) == VAR_DECL); |
1683 | ||
1684 | if (DECL_INITIAL (global)) | |
1685 | walk_tree (&DECL_INITIAL (global), scan_for_refs, NULL, visited_nodes); | |
ea900239 DB |
1686 | } |
1687 | ||
1688 | /* This is the main routine for finding the reference patterns for | |
1689 | global variables within a function FN. */ | |
1690 | ||
1691 | static void | |
1692 | analyze_function (struct cgraph_node *fn) | |
1693 | { | |
1694 | tree decl = fn->decl; | |
1695 | check_function_parameter_and_return_types (decl, | |
1696 | fn->local.externally_visible); | |
1697 | if (dump_file) | |
1698 | fprintf (dump_file, "\n local analysis of %s", cgraph_node_name (fn)); | |
1699 | ||
1700 | { | |
1701 | struct function *this_cfun = DECL_STRUCT_FUNCTION (decl); | |
1702 | basic_block this_block; | |
1703 | ||
1704 | FOR_EACH_BB_FN (this_block, this_cfun) | |
1705 | { | |
1706 | block_stmt_iterator bsi; | |
1707 | for (bsi = bsi_start (this_block); !bsi_end_p (bsi); bsi_next (&bsi)) | |
1708 | walk_tree (bsi_stmt_ptr (bsi), scan_for_refs, | |
1709 | fn, visited_nodes); | |
1710 | } | |
1711 | } | |
1712 | ||
1713 | /* There may be const decls with interesting right hand sides. */ | |
1714 | if (DECL_STRUCT_FUNCTION (decl)) | |
1715 | { | |
1716 | tree step; | |
1717 | for (step = DECL_STRUCT_FUNCTION (decl)->unexpanded_var_list; | |
1718 | step; | |
1719 | step = TREE_CHAIN (step)) | |
1720 | { | |
1721 | tree var = TREE_VALUE (step); | |
1722 | if (TREE_CODE (var) == VAR_DECL | |
1723 | && DECL_INITIAL (var) | |
1724 | && !TREE_STATIC (var)) | |
1725 | walk_tree (&DECL_INITIAL (var), scan_for_refs, | |
1726 | fn, visited_nodes); | |
1727 | get_canon_type (TREE_TYPE (var), false, false); | |
1728 | } | |
1729 | } | |
1730 | } | |
1731 | ||
1732 | \f | |
1733 | ||
1734 | /* Convert a type_UID into a type. */ | |
1735 | static tree | |
1736 | type_for_uid (int uid) | |
1737 | { | |
1738 | splay_tree_node result = | |
1739 | splay_tree_lookup (uid_to_canon_type, (splay_tree_key) uid); | |
1740 | ||
1741 | if (result) | |
1742 | return (tree) result->value; | |
1743 | else return NULL; | |
1744 | } | |
1745 | ||
1746 | /* Return the a bitmap with the subtypes of the type for UID. If it | |
1747 | does not exist, return either NULL or a new bitmap depending on the | |
1748 | value of CREATE. */ | |
1749 | ||
1750 | static bitmap | |
1751 | subtype_map_for_uid (int uid, bool create) | |
1752 | { | |
1753 | splay_tree_node result = splay_tree_lookup (uid_to_subtype_map, | |
1754 | (splay_tree_key) uid); | |
1755 | ||
1756 | if (result) | |
1757 | return (bitmap) result->value; | |
1758 | else if (create) | |
1759 | { | |
1760 | bitmap subtype_map = BITMAP_ALLOC (&ipa_obstack); | |
1761 | splay_tree_insert (uid_to_subtype_map, | |
1762 | uid, | |
1763 | (splay_tree_value)subtype_map); | |
1764 | return subtype_map; | |
1765 | } | |
1766 | else return NULL; | |
1767 | } | |
1768 | ||
1769 | /* Mark all of the supertypes and field types of TYPE as being seen. | |
1770 | Also accumulate the subtypes for each type so that | |
1771 | close_types_full_escape can mark a subtype as escaping if the | |
1772 | supertype escapes. */ | |
1773 | ||
1774 | static void | |
1775 | close_type_seen (tree type) | |
1776 | { | |
1777 | tree field; | |
1778 | int i, uid; | |
1779 | tree binfo, base_binfo; | |
1780 | ||
1781 | /* See thru all pointer tos and array ofs. */ | |
1782 | type = get_canon_type (type, true, true); | |
1783 | if (!type) | |
1784 | return; | |
1785 | ||
1786 | uid = TYPE_UID (type); | |
1787 | ||
1788 | if (bitmap_bit_p (been_there_done_that, uid)) | |
1789 | return; | |
1790 | bitmap_set_bit (been_there_done_that, uid); | |
1791 | ||
a4174ebf | 1792 | /* If we are doing a language with a type hierarchy, mark all of |
ea900239 DB |
1793 | the superclasses. */ |
1794 | if (TYPE_BINFO (type)) | |
1795 | for (binfo = TYPE_BINFO (type), i = 0; | |
1796 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
1797 | { | |
1798 | tree binfo_type = BINFO_TYPE (base_binfo); | |
1799 | bitmap subtype_map = subtype_map_for_uid | |
1800 | (TYPE_UID (TYPE_MAIN_VARIANT (binfo_type)), true); | |
1801 | bitmap_set_bit (subtype_map, uid); | |
1802 | close_type_seen (get_canon_type (binfo_type, true, true)); | |
1803 | } | |
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 | if (TREE_CODE (field) != FIELD_DECL) | |
1813 | continue; | |
1814 | ||
1815 | field_type = TREE_TYPE (field); | |
1816 | if (ipa_type_escape_star_count_of_interesting_or_array_type (field_type) >= 0) | |
1817 | close_type_seen (get_canon_type (field_type, true, true)); | |
1818 | } | |
1819 | } | |
1820 | ||
1821 | /* Take a TYPE that has been passed by value to an external function | |
1822 | and mark all of the fields that have pointer types as escaping. For | |
1823 | any of the non pointer types that are structures or unions, | |
1824 | recurse. TYPE is never a pointer type. */ | |
1825 | ||
1826 | static void | |
1827 | close_type_exposed_parameter (tree type) | |
1828 | { | |
1829 | tree field; | |
1830 | int uid; | |
1831 | ||
1832 | type = get_canon_type (type, false, false); | |
1833 | if (!type) | |
1834 | return; | |
1835 | uid = TYPE_UID (type); | |
1836 | gcc_assert (!POINTER_TYPE_P (type)); | |
1837 | ||
1838 | if (bitmap_bit_p (been_there_done_that, uid)) | |
1839 | return; | |
1840 | bitmap_set_bit (been_there_done_that, uid); | |
1841 | ||
1842 | /* If the field is a struct or union type, mark all of the | |
1843 | subfields. */ | |
1844 | for (field = TYPE_FIELDS (type); | |
1845 | field; | |
1846 | field = TREE_CHAIN (field)) | |
1847 | { | |
1848 | tree field_type; | |
1849 | ||
1850 | if (TREE_CODE (field) != FIELD_DECL) | |
1851 | continue; | |
1852 | ||
1853 | field_type = get_canon_type (TREE_TYPE (field), false, false); | |
1854 | mark_interesting_type (field_type, EXPOSED_PARAMETER); | |
1855 | ||
1856 | /* Only recurse for non pointer types of structures and unions. */ | |
1857 | if (ipa_type_escape_star_count_of_interesting_type (field_type) == 0) | |
1858 | close_type_exposed_parameter (field_type); | |
1859 | } | |
1860 | } | |
1861 | ||
1862 | /* The next function handles the case where a type fully escapes. | |
1863 | This means that not only does the type itself escape, | |
1864 | ||
1865 | a) the type of every field recursively escapes | |
1866 | b) the type of every subtype escapes as well as the super as well | |
1867 | as all of the pointer to types for each field. | |
1868 | ||
1869 | Note that pointer to types are not marked as escaping. If the | |
1870 | pointed to type escapes, the pointer to type also escapes. | |
1871 | ||
1872 | Take a TYPE that has had the address taken for an instance of it | |
1873 | and mark all of the types for its fields as having their addresses | |
1874 | taken. */ | |
1875 | ||
1876 | static void | |
1877 | close_type_full_escape (tree type) | |
1878 | { | |
1879 | tree field; | |
1880 | unsigned int i; | |
1881 | int uid; | |
1882 | tree binfo, base_binfo; | |
1883 | bitmap_iterator bi; | |
1884 | bitmap subtype_map; | |
1885 | splay_tree_node address_result; | |
1886 | ||
1887 | /* Strip off any pointer or array types. */ | |
1888 | type = get_canon_type (type, true, true); | |
1889 | if (!type) | |
1890 | return; | |
1891 | uid = TYPE_UID (type); | |
1892 | ||
1893 | if (bitmap_bit_p (been_there_done_that, uid)) | |
1894 | return; | |
1895 | bitmap_set_bit (been_there_done_that, uid); | |
1896 | ||
1897 | subtype_map = subtype_map_for_uid (uid, false); | |
1898 | ||
a4174ebf | 1899 | /* If we are doing a language with a type hierarchy, mark all of |
ea900239 DB |
1900 | the superclasses. */ |
1901 | if (TYPE_BINFO (type)) | |
1902 | for (binfo = TYPE_BINFO (type), i = 0; | |
1903 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
1904 | { | |
1905 | tree binfotype = BINFO_TYPE (base_binfo); | |
1906 | binfotype = mark_type (binfotype, FULL_ESCAPE); | |
1907 | close_type_full_escape (binfotype); | |
1908 | } | |
1909 | ||
1910 | /* Mark as escaped any types that have been down casted to | |
1911 | this type. */ | |
1912 | if (subtype_map) | |
1913 | EXECUTE_IF_SET_IN_BITMAP (subtype_map, 0, i, bi) | |
1914 | { | |
1915 | tree subtype = type_for_uid (i); | |
1916 | subtype = mark_type (subtype, FULL_ESCAPE); | |
1917 | close_type_full_escape (subtype); | |
1918 | } | |
1919 | ||
1920 | /* If the field is a struct or union type, mark all of the | |
1921 | subfields. */ | |
1922 | for (field = TYPE_FIELDS (type); | |
1923 | field; | |
1924 | field = TREE_CHAIN (field)) | |
1925 | { | |
1926 | tree field_type; | |
1927 | if (TREE_CODE (field) != FIELD_DECL) | |
1928 | continue; | |
1929 | ||
1930 | field_type = TREE_TYPE (field); | |
1931 | if (ipa_type_escape_star_count_of_interesting_or_array_type (field_type) >= 0) | |
1932 | { | |
1933 | field_type = mark_type (field_type, FULL_ESCAPE); | |
1934 | close_type_full_escape (field_type); | |
1935 | } | |
1936 | } | |
1937 | ||
1938 | /* For all of the types A that contain this type B and were part of | |
1939 | an expression like "&...A.B...", mark the A's as escaping. */ | |
1940 | address_result = splay_tree_lookup (uid_to_addressof_up_map, | |
1941 | (splay_tree_key) uid); | |
1942 | if (address_result) | |
1943 | { | |
1944 | bitmap containing_classes = (bitmap) address_result->value; | |
1945 | EXECUTE_IF_SET_IN_BITMAP (containing_classes, 0, i, bi) | |
1946 | { | |
1947 | close_type_full_escape (type_for_uid (i)); | |
1948 | } | |
1949 | } | |
1950 | } | |
1951 | ||
1952 | /* Transitively close the addressof bitmap for the type with UID. | |
569b7f6a | 1953 | This means that if we had a.b and b.c, a would have both b and c in |
ea900239 DB |
1954 | its maps. */ |
1955 | ||
1956 | static bitmap | |
1957 | close_addressof_down (int uid) | |
1958 | { | |
1959 | bitmap_iterator bi; | |
1960 | splay_tree_node result = | |
1961 | splay_tree_lookup (uid_to_addressof_down_map, (splay_tree_key) uid); | |
1962 | bitmap map = NULL; | |
1963 | bitmap new_map; | |
1964 | unsigned int i; | |
1965 | ||
1966 | if (result) | |
1967 | map = (bitmap) result->value; | |
1968 | else | |
1969 | return NULL; | |
1970 | ||
1971 | if (bitmap_bit_p (been_there_done_that, uid)) | |
1972 | return map; | |
1973 | bitmap_set_bit (been_there_done_that, uid); | |
1974 | ||
1975 | /* If the type escapes, get rid of the addressof map, it will not be | |
1976 | needed. */ | |
1977 | if (bitmap_bit_p (global_types_full_escape, uid)) | |
1978 | { | |
1979 | BITMAP_FREE (map); | |
1980 | splay_tree_remove (uid_to_addressof_down_map, (splay_tree_key) uid); | |
1981 | return NULL; | |
1982 | } | |
1983 | ||
1984 | /* The new_map will have all of the bits for the enclosed fields and | |
1985 | will have the unique id version of the old map. */ | |
1986 | new_map = BITMAP_ALLOC (&ipa_obstack); | |
1987 | ||
1988 | EXECUTE_IF_SET_IN_BITMAP (map, 0, i, bi) | |
1989 | { | |
1990 | bitmap submap = close_addressof_down (i); | |
1991 | bitmap_set_bit (new_map, i); | |
1992 | if (submap) | |
1993 | bitmap_ior_into (new_map, submap); | |
1994 | } | |
1995 | result->value = (splay_tree_value) new_map; | |
1996 | ||
1997 | BITMAP_FREE (map); | |
1998 | return new_map; | |
1999 | } | |
2000 | ||
2001 | \f | |
2002 | /* The main entry point for type escape analysis. */ | |
2003 | ||
c2924966 | 2004 | static unsigned int |
ea900239 DB |
2005 | type_escape_execute (void) |
2006 | { | |
2007 | struct cgraph_node *node; | |
8a4a83ed | 2008 | struct varpool_node *vnode; |
ea900239 DB |
2009 | unsigned int i; |
2010 | bitmap_iterator bi; | |
2011 | splay_tree_node result; | |
2012 | ||
2013 | ipa_init (); | |
2014 | ||
2015 | /* Process all of the variables first. */ | |
68e56cc4 | 2016 | FOR_EACH_STATIC_VARIABLE (vnode) |
ea900239 DB |
2017 | analyze_variable (vnode); |
2018 | ||
2019 | /* Process all of the functions. next | |
2020 | ||
2021 | We do not want to process any of the clones so we check that this | |
2022 | is a master clone. However, we do need to process any | |
2023 | AVAIL_OVERWRITABLE functions (these are never clones) because | |
2024 | they may cause a type variable to escape. | |
2025 | */ | |
2026 | for (node = cgraph_nodes; node; node = node->next) | |
2027 | if (node->analyzed | |
2028 | && (cgraph_is_master_clone (node) | |
2029 | || (cgraph_function_body_availability (node) == AVAIL_OVERWRITABLE))) | |
2030 | analyze_function (node); | |
2031 | ||
2032 | ||
2033 | pointer_set_destroy (visited_nodes); | |
2034 | visited_nodes = NULL; | |
2035 | ||
2036 | /* Do all of the closures to discover which types escape the | |
2037 | compilation unit. */ | |
2038 | ||
2039 | been_there_done_that = BITMAP_ALLOC (&ipa_obstack); | |
2040 | bitmap_tmp = BITMAP_ALLOC (&ipa_obstack); | |
2041 | ||
2042 | /* Examine the types that we have directly seen in scanning the code | |
2043 | and add to that any contained types or superclasses. */ | |
2044 | ||
2045 | bitmap_copy (bitmap_tmp, global_types_seen); | |
2046 | EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi) | |
2047 | { | |
2048 | tree type = type_for_uid (i); | |
2049 | /* Only look at records and unions and pointer tos. */ | |
2050 | if (ipa_type_escape_star_count_of_interesting_or_array_type (type) >= 0) | |
2051 | close_type_seen (type); | |
2052 | } | |
2053 | bitmap_clear (been_there_done_that); | |
2054 | ||
2055 | /* Examine all of the types passed by value and mark any enclosed | |
2056 | pointer types as escaping. */ | |
2057 | bitmap_copy (bitmap_tmp, global_types_exposed_parameter); | |
2058 | EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi) | |
2059 | { | |
2060 | close_type_exposed_parameter (type_for_uid (i)); | |
2061 | } | |
2062 | bitmap_clear (been_there_done_that); | |
2063 | ||
2064 | /* Close the types for escape. If something escapes, then any | |
2065 | enclosed types escape as well as any subtypes. */ | |
2066 | bitmap_copy (bitmap_tmp, global_types_full_escape); | |
2067 | EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi) | |
2068 | { | |
2069 | close_type_full_escape (type_for_uid (i)); | |
2070 | } | |
2071 | bitmap_clear (been_there_done_that); | |
2072 | ||
2073 | /* Before this pass, the uid_to_addressof_down_map for type X | |
2074 | contained an entry for Y if there had been an operation of the | |
2075 | form &X.Y. This step adds all of the fields contained within Y | |
2076 | (recursively) to X's map. */ | |
2077 | ||
2078 | result = splay_tree_min (uid_to_addressof_down_map); | |
2079 | while (result) | |
2080 | { | |
2081 | int uid = result->key; | |
2082 | /* Close the addressof map, i.e. copy all of the transitive | |
2083 | substructures up to this level. */ | |
2084 | close_addressof_down (uid); | |
2085 | result = splay_tree_successor (uid_to_addressof_down_map, uid); | |
2086 | } | |
2087 | ||
2088 | /* Do not need the array types and pointer types in the persistent | |
2089 | data structures. */ | |
2090 | result = splay_tree_min (all_canon_types); | |
2091 | while (result) | |
2092 | { | |
2093 | tree type = (tree) result->value; | |
2094 | tree key = (tree) result->key; | |
2095 | if (POINTER_TYPE_P (type) | |
2096 | || TREE_CODE (type) == ARRAY_TYPE) | |
2097 | { | |
2098 | splay_tree_remove (all_canon_types, (splay_tree_key) result->key); | |
2099 | splay_tree_remove (type_to_canon_type, (splay_tree_key) type); | |
2100 | splay_tree_remove (uid_to_canon_type, (splay_tree_key) TYPE_UID (type)); | |
2101 | bitmap_clear_bit (global_types_seen, TYPE_UID (type)); | |
2102 | } | |
2103 | result = splay_tree_successor (all_canon_types, (splay_tree_key) key); | |
2104 | } | |
2105 | ||
ea900239 DB |
2106 | if (dump_file) |
2107 | { | |
2108 | EXECUTE_IF_SET_IN_BITMAP (global_types_seen, 0, i, bi) | |
2109 | { | |
2110 | /* The pointer types are in the global_types_full_escape | |
2111 | bitmap but not in the backwards map. They also contain | |
2112 | no useful information since they are not marked. */ | |
2113 | tree type = type_for_uid (i); | |
2114 | fprintf(dump_file, "type %d ", i); | |
2115 | print_generic_expr (dump_file, type, 0); | |
2116 | if (bitmap_bit_p (global_types_full_escape, i)) | |
2117 | fprintf(dump_file, " escaped\n"); | |
2118 | else | |
2119 | fprintf(dump_file, " contained\n"); | |
2120 | } | |
2121 | } | |
ea900239 DB |
2122 | |
2123 | /* Get rid of uid_to_addressof_up_map and its bitmaps. */ | |
2124 | result = splay_tree_min (uid_to_addressof_up_map); | |
2125 | while (result) | |
2126 | { | |
2127 | int uid = (int)result->key; | |
2128 | bitmap bm = (bitmap)result->value; | |
2129 | ||
2130 | BITMAP_FREE (bm); | |
2131 | splay_tree_remove (uid_to_addressof_up_map, (splay_tree_key) uid); | |
2132 | result = splay_tree_successor (uid_to_addressof_up_map, uid); | |
2133 | } | |
2134 | ||
2135 | /* Get rid of the subtype map. */ | |
2136 | result = splay_tree_min (uid_to_subtype_map); | |
2137 | while (result) | |
2138 | { | |
2139 | bitmap b = (bitmap)result->value; | |
2140 | BITMAP_FREE(b); | |
2141 | splay_tree_remove (uid_to_subtype_map, result->key); | |
2142 | result = splay_tree_min (uid_to_subtype_map); | |
2143 | } | |
2144 | splay_tree_delete (uid_to_subtype_map); | |
2145 | uid_to_subtype_map = NULL; | |
2146 | ||
2147 | BITMAP_FREE (global_types_exposed_parameter); | |
2148 | BITMAP_FREE (been_there_done_that); | |
2149 | BITMAP_FREE (bitmap_tmp); | |
c2924966 | 2150 | return 0; |
ea900239 DB |
2151 | } |
2152 | ||
2153 | static bool | |
2154 | gate_type_escape_vars (void) | |
2155 | { | |
2156 | return (flag_unit_at_a_time != 0 && flag_ipa_type_escape | |
2157 | /* Don't bother doing anything if the program has errors. */ | |
2158 | && !(errorcount || sorrycount)); | |
2159 | } | |
2160 | ||
2161 | struct tree_opt_pass pass_ipa_type_escape = | |
2162 | { | |
2163 | "type-escape-var", /* name */ | |
2164 | gate_type_escape_vars, /* gate */ | |
2165 | type_escape_execute, /* execute */ | |
2166 | NULL, /* sub */ | |
2167 | NULL, /* next */ | |
2168 | 0, /* static_pass_number */ | |
2169 | TV_IPA_TYPE_ESCAPE, /* tv_id */ | |
2170 | 0, /* properties_required */ | |
2171 | 0, /* properties_provided */ | |
2172 | 0, /* properties_destroyed */ | |
2173 | 0, /* todo_flags_start */ | |
2174 | 0, /* todo_flags_finish */ | |
2175 | 0 /* letter */ | |
2176 | }; | |
2177 |