1 | /* Callgraph based analysis of static variables. |
2 | Copyright (C) 2004-2023 Free Software Foundation, Inc. |
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 3, 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 COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ |
20 | |
21 | /* This file marks functions as being either const (TREE_READONLY) or |
22 | pure (DECL_PURE_P). It can also set a variant of these that |
23 | are allowed to loop indefinitely (DECL_LOOPING_CONST_PURE_P). |
24 | |
25 | This must be run after inlining decisions have been made since |
26 | otherwise, the local sets will not contain information that is |
27 | consistent with post inlined state. The global sets are not prone |
28 | to this problem since they are by definition transitive. */ |
29 | |
30 | /* The code in this module is called by the ipa pass manager. It |
31 | should be one of the later passes since it's information is used by |
32 | the rest of the compilation. */ |
33 | |
34 | #include "config.h" |
35 | #include "system.h" |
36 | #include "coretypes.h" |
37 | #include "backend.h" |
38 | #include "target.h" |
39 | #include "tree.h" |
40 | #include "gimple.h" |
41 | #include "tree-pass.h" |
42 | #include "tree-streamer.h" |
43 | #include "cgraph.h" |
44 | #include "diagnostic.h" |
45 | #include "calls.h" |
46 | #include "cfganal.h" |
47 | #include "tree-eh.h" |
48 | #include "gimple-iterator.h" |
49 | #include "gimple-walk.h" |
50 | #include "tree-cfg.h" |
51 | #include "tree-ssa-loop-niter.h" |
52 | #include "langhooks.h" |
53 | #include "ipa-utils.h" |
54 | #include "gimple-pretty-print.h" |
55 | #include "cfgloop.h" |
56 | #include "tree-scalar-evolution.h" |
57 | #include "intl.h" |
58 | #include "opts.h" |
59 | #include "ssa.h" |
60 | #include "alloc-pool.h" |
61 | #include "symbol-summary.h" |
62 | #include "ipa-prop.h" |
63 | #include "ipa-fnsummary.h" |
64 | #include "symtab-thunks.h" |
65 | #include "dbgcnt.h" |
66 | |
67 | /* Lattice values for const and pure functions. Everything starts out |
68 | being const, then may drop to pure and then neither depending on |
69 | what is found. */ |
70 | enum pure_const_state_e |
71 | { |
72 | IPA_CONST, |
73 | IPA_PURE, |
74 | IPA_NEITHER |
75 | }; |
76 | |
77 | static const char *pure_const_names[3] = {"const" , "pure" , "neither" }; |
78 | |
79 | enum malloc_state_e |
80 | { |
81 | STATE_MALLOC_TOP, |
82 | STATE_MALLOC, |
83 | STATE_MALLOC_BOTTOM |
84 | }; |
85 | |
86 | static const char *malloc_state_names[] = {"malloc_top" , "malloc" , "malloc_bottom" }; |
87 | |
88 | /* Holder for the const_state. There is one of these per function |
89 | decl. */ |
90 | class funct_state_d |
91 | { |
92 | public: |
93 | funct_state_d (): pure_const_state (IPA_NEITHER), |
94 | state_previously_known (IPA_NEITHER), looping_previously_known (true), |
95 | looping (true), can_throw (true), can_free (true), |
96 | malloc_state (STATE_MALLOC_BOTTOM) {} |
97 | |
98 | funct_state_d (const funct_state_d &s): pure_const_state (s.pure_const_state), |
99 | state_previously_known (s.state_previously_known), |
100 | looping_previously_known (s.looping_previously_known), |
101 | looping (s.looping), can_throw (s.can_throw), can_free (s.can_free), |
102 | malloc_state (s.malloc_state) {} |
103 | |
104 | /* See above. */ |
105 | enum pure_const_state_e pure_const_state; |
106 | /* What user set here; we can be always sure about this. */ |
107 | enum pure_const_state_e state_previously_known; |
108 | bool looping_previously_known; |
109 | |
110 | /* True if the function could possibly infinite loop. There are a |
111 | lot of ways that this could be determined. We are pretty |
112 | conservative here. While it is possible to cse pure and const |
113 | calls, it is not legal to have dce get rid of the call if there |
114 | is a possibility that the call could infinite loop since this is |
115 | a behavioral change. */ |
116 | bool looping; |
117 | |
118 | bool can_throw; |
119 | |
120 | /* If function can call free, munmap or otherwise make previously |
121 | non-trapping memory accesses trapping. */ |
122 | bool can_free; |
123 | |
124 | enum malloc_state_e malloc_state; |
125 | }; |
126 | |
127 | typedef class funct_state_d * funct_state; |
128 | |
129 | /* The storage of the funct_state is abstracted because there is the |
130 | possibility that it may be desirable to move this to the cgraph |
131 | local info. */ |
132 | |
133 | class funct_state_summary_t: |
134 | public fast_function_summary <funct_state_d *, va_heap> |
135 | { |
136 | public: |
137 | funct_state_summary_t (symbol_table *symtab): |
138 | fast_function_summary <funct_state_d *, va_heap> (symtab) {} |
139 | |
140 | void insert (cgraph_node *, funct_state_d *state) final override; |
141 | void duplicate (cgraph_node *src_node, cgraph_node *dst_node, |
142 | funct_state_d *src_data, |
143 | funct_state_d *dst_data) final override; |
144 | }; |
145 | |
146 | static funct_state_summary_t *funct_state_summaries = NULL; |
147 | |
148 | static bool gate_pure_const (void); |
149 | |
150 | namespace { |
151 | |
152 | const pass_data pass_data_ipa_pure_const = |
153 | { |
154 | .type: IPA_PASS, /* type */ |
155 | .name: "pure-const" , /* name */ |
156 | .optinfo_flags: OPTGROUP_NONE, /* optinfo_flags */ |
157 | .tv_id: TV_IPA_PURE_CONST, /* tv_id */ |
158 | .properties_required: 0, /* properties_required */ |
159 | .properties_provided: 0, /* properties_provided */ |
160 | .properties_destroyed: 0, /* properties_destroyed */ |
161 | .todo_flags_start: 0, /* todo_flags_start */ |
162 | .todo_flags_finish: 0, /* todo_flags_finish */ |
163 | }; |
164 | |
165 | class pass_ipa_pure_const : public ipa_opt_pass_d |
166 | { |
167 | public: |
168 | pass_ipa_pure_const(gcc::context *ctxt); |
169 | |
170 | /* opt_pass methods: */ |
171 | bool gate (function *) final override { return gate_pure_const (); } |
172 | unsigned int execute (function *fun) final override; |
173 | |
174 | void register_hooks (void); |
175 | |
176 | private: |
177 | bool init_p; |
178 | }; // class pass_ipa_pure_const |
179 | |
180 | } // anon namespace |
181 | |
182 | /* Try to guess if function body will always be visible to compiler |
183 | when compiling the call and whether compiler will be able |
184 | to propagate the information by itself. */ |
185 | |
186 | static bool |
187 | function_always_visible_to_compiler_p (tree decl) |
188 | { |
189 | return (!TREE_PUBLIC (decl) || DECL_DECLARED_INLINE_P (decl) |
190 | || DECL_COMDAT (decl)); |
191 | } |
192 | |
193 | /* Emit suggestion about attribute ATTRIB_NAME for DECL. KNOWN_FINITE |
194 | is true if the function is known to be finite. The diagnostic is |
195 | controlled by OPTION. WARNED_ABOUT is a hash_set<tree> unique for |
196 | OPTION, this function may initialize it and it is always returned |
197 | by the function. */ |
198 | |
199 | static hash_set<tree> * |
200 | suggest_attribute (int option, tree decl, bool known_finite, |
201 | hash_set<tree> *warned_about, |
202 | const char * attrib_name) |
203 | { |
204 | if (!option_enabled (opt_idx: option, lang_mask: lang_hooks.option_lang_mask (), opts: &global_options)) |
205 | return warned_about; |
206 | if (TREE_THIS_VOLATILE (decl) |
207 | || (known_finite && function_always_visible_to_compiler_p (decl))) |
208 | return warned_about; |
209 | |
210 | if (!warned_about) |
211 | warned_about = new hash_set<tree>; |
212 | if (warned_about->contains (k: decl)) |
213 | return warned_about; |
214 | warned_about->add (k: decl); |
215 | warning_at (DECL_SOURCE_LOCATION (decl), |
216 | option, |
217 | known_finite |
218 | ? G_("function might be candidate for attribute %qs" ) |
219 | : G_("function might be candidate for attribute %qs" |
220 | " if it is known to return normally" ), attrib_name); |
221 | return warned_about; |
222 | } |
223 | |
224 | /* Emit suggestion about __attribute_((pure)) for DECL. KNOWN_FINITE |
225 | is true if the function is known to be finite. */ |
226 | |
227 | static void |
228 | warn_function_pure (tree decl, bool known_finite) |
229 | { |
230 | /* Declaring a void function pure makes no sense and is diagnosed |
231 | by -Wattributes because calling it would have no effect. */ |
232 | if (VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl)))) |
233 | return; |
234 | |
235 | static hash_set<tree> *warned_about; |
236 | warned_about |
237 | = suggest_attribute (option: OPT_Wsuggest_attribute_pure, decl, |
238 | known_finite, warned_about, attrib_name: "pure" ); |
239 | } |
240 | |
241 | /* Emit suggestion about __attribute_((const)) for DECL. KNOWN_FINITE |
242 | is true if the function is known to be finite. */ |
243 | |
244 | static void |
245 | warn_function_const (tree decl, bool known_finite) |
246 | { |
247 | /* Declaring a void function const makes no sense is diagnosed |
248 | by -Wattributes because calling it would have no effect. */ |
249 | if (VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl)))) |
250 | return; |
251 | |
252 | static hash_set<tree> *warned_about; |
253 | warned_about |
254 | = suggest_attribute (option: OPT_Wsuggest_attribute_const, decl, |
255 | known_finite, warned_about, attrib_name: "const" ); |
256 | } |
257 | |
258 | /* Emit suggestion about __attribute__((malloc)) for DECL. */ |
259 | |
260 | static void |
261 | warn_function_malloc (tree decl) |
262 | { |
263 | static hash_set<tree> *warned_about; |
264 | warned_about |
265 | = suggest_attribute (option: OPT_Wsuggest_attribute_malloc, decl, |
266 | known_finite: true, warned_about, attrib_name: "malloc" ); |
267 | } |
268 | |
269 | /* Emit suggestion about __attribute__((noreturn)) for DECL. */ |
270 | |
271 | static void |
272 | warn_function_noreturn (tree decl) |
273 | { |
274 | tree original_decl = decl; |
275 | |
276 | static hash_set<tree> *warned_about; |
277 | if (!lang_hooks.missing_noreturn_ok_p (decl) |
278 | && targetm.warn_func_return (decl)) |
279 | warned_about |
280 | = suggest_attribute (option: OPT_Wsuggest_attribute_noreturn, decl: original_decl, |
281 | known_finite: true, warned_about, attrib_name: "noreturn" ); |
282 | } |
283 | |
284 | void |
285 | warn_function_cold (tree decl) |
286 | { |
287 | tree original_decl = decl; |
288 | |
289 | static hash_set<tree> *warned_about; |
290 | warned_about |
291 | = suggest_attribute (option: OPT_Wsuggest_attribute_cold, decl: original_decl, |
292 | known_finite: true, warned_about, attrib_name: "cold" ); |
293 | } |
294 | |
295 | /* Check to see if the use (or definition when CHECKING_WRITE is true) |
296 | variable T is legal in a function that is either pure or const. */ |
297 | |
298 | static inline void |
299 | check_decl (funct_state local, |
300 | tree t, bool checking_write, bool ipa) |
301 | { |
302 | /* Do not want to do anything with volatile except mark any |
303 | function that uses one to be not const or pure. */ |
304 | if (TREE_THIS_VOLATILE (t)) |
305 | { |
306 | local->pure_const_state = IPA_NEITHER; |
307 | if (dump_file) |
308 | fprintf (stream: dump_file, format: " Volatile operand is not const/pure\n" ); |
309 | return; |
310 | } |
311 | |
312 | /* Do not care about a local automatic that is not static. */ |
313 | if (!TREE_STATIC (t) && !DECL_EXTERNAL (t)) |
314 | return; |
315 | |
316 | /* If the variable has the "used" attribute, treat it as if it had a |
317 | been touched by the devil. */ |
318 | if (DECL_PRESERVE_P (t)) |
319 | { |
320 | local->pure_const_state = IPA_NEITHER; |
321 | if (dump_file) |
322 | fprintf (stream: dump_file, format: " Used static/global variable is not const/pure\n" ); |
323 | return; |
324 | } |
325 | |
326 | /* In IPA mode we are not interested in checking actual loads and stores; |
327 | they will be processed at propagation time using ipa_ref. */ |
328 | if (ipa) |
329 | return; |
330 | |
331 | /* Since we have dealt with the locals and params cases above, if we |
332 | are CHECKING_WRITE, this cannot be a pure or constant |
333 | function. */ |
334 | if (checking_write) |
335 | { |
336 | local->pure_const_state = IPA_NEITHER; |
337 | if (dump_file) |
338 | fprintf (stream: dump_file, format: " static/global memory write is not const/pure\n" ); |
339 | return; |
340 | } |
341 | |
342 | if (DECL_EXTERNAL (t) || TREE_PUBLIC (t)) |
343 | { |
344 | /* Readonly reads are safe. */ |
345 | if (TREE_READONLY (t)) |
346 | return; /* Read of a constant, do not change the function state. */ |
347 | else |
348 | { |
349 | if (dump_file) |
350 | fprintf (stream: dump_file, format: " global memory read is not const\n" ); |
351 | /* Just a regular read. */ |
352 | if (local->pure_const_state == IPA_CONST) |
353 | local->pure_const_state = IPA_PURE; |
354 | } |
355 | } |
356 | else |
357 | { |
358 | /* Compilation level statics can be read if they are readonly |
359 | variables. */ |
360 | if (TREE_READONLY (t)) |
361 | return; |
362 | |
363 | if (dump_file) |
364 | fprintf (stream: dump_file, format: " static memory read is not const\n" ); |
365 | /* Just a regular read. */ |
366 | if (local->pure_const_state == IPA_CONST) |
367 | local->pure_const_state = IPA_PURE; |
368 | } |
369 | } |
370 | |
371 | |
372 | /* Check to see if the use (or definition when CHECKING_WRITE is true) |
373 | variable T is legal in a function that is either pure or const. */ |
374 | |
375 | static inline void |
376 | check_op (funct_state local, tree t, bool checking_write) |
377 | { |
378 | t = get_base_address (t); |
379 | if (t && TREE_THIS_VOLATILE (t)) |
380 | { |
381 | local->pure_const_state = IPA_NEITHER; |
382 | if (dump_file) |
383 | fprintf (stream: dump_file, format: " Volatile indirect ref is not const/pure\n" ); |
384 | return; |
385 | } |
386 | else if (refs_local_or_readonly_memory_p (t)) |
387 | { |
388 | if (dump_file) |
389 | fprintf (stream: dump_file, format: " Indirect ref to local or readonly " |
390 | "memory is OK\n" ); |
391 | return; |
392 | } |
393 | else if (checking_write) |
394 | { |
395 | local->pure_const_state = IPA_NEITHER; |
396 | if (dump_file) |
397 | fprintf (stream: dump_file, format: " Indirect ref write is not const/pure\n" ); |
398 | return; |
399 | } |
400 | else |
401 | { |
402 | if (dump_file) |
403 | fprintf (stream: dump_file, format: " Indirect ref read is not const\n" ); |
404 | if (local->pure_const_state == IPA_CONST) |
405 | local->pure_const_state = IPA_PURE; |
406 | } |
407 | } |
408 | |
409 | /* compute state based on ECF FLAGS and store to STATE and LOOPING. */ |
410 | |
411 | static void |
412 | state_from_flags (enum pure_const_state_e *state, bool *looping, |
413 | int flags, bool cannot_lead_to_return) |
414 | { |
415 | *looping = false; |
416 | if (flags & ECF_LOOPING_CONST_OR_PURE) |
417 | { |
418 | *looping = true; |
419 | if (dump_file && (dump_flags & TDF_DETAILS)) |
420 | fprintf (stream: dump_file, format: " looping\n" ); |
421 | } |
422 | if (flags & ECF_CONST) |
423 | { |
424 | *state = IPA_CONST; |
425 | if (dump_file && (dump_flags & TDF_DETAILS)) |
426 | fprintf (stream: dump_file, format: " const\n" ); |
427 | } |
428 | else if (flags & ECF_PURE) |
429 | { |
430 | *state = IPA_PURE; |
431 | if (dump_file && (dump_flags & TDF_DETAILS)) |
432 | fprintf (stream: dump_file, format: " pure\n" ); |
433 | } |
434 | else if (cannot_lead_to_return) |
435 | { |
436 | *state = IPA_PURE; |
437 | *looping = true; |
438 | if (dump_file && (dump_flags & TDF_DETAILS)) |
439 | fprintf (stream: dump_file, format: " ignoring side effects->pure looping\n" ); |
440 | } |
441 | else |
442 | { |
443 | if (dump_file && (dump_flags & TDF_DETAILS)) |
444 | fprintf (stream: dump_file, format: " neither\n" ); |
445 | *state = IPA_NEITHER; |
446 | *looping = true; |
447 | } |
448 | } |
449 | |
450 | /* Merge STATE and STATE2 and LOOPING and LOOPING2 and store |
451 | into STATE and LOOPING better of the two variants. |
452 | Be sure to merge looping correctly. IPA_NEITHER functions |
453 | have looping 0 even if they don't have to return. */ |
454 | |
455 | static inline void |
456 | better_state (enum pure_const_state_e *state, bool *looping, |
457 | enum pure_const_state_e state2, bool looping2) |
458 | { |
459 | if (state2 < *state) |
460 | { |
461 | if (*state == IPA_NEITHER) |
462 | *looping = looping2; |
463 | else |
464 | *looping = MIN (*looping, looping2); |
465 | *state = state2; |
466 | } |
467 | else if (state2 != IPA_NEITHER) |
468 | *looping = MIN (*looping, looping2); |
469 | } |
470 | |
471 | /* Merge STATE and STATE2 and LOOPING and LOOPING2 and store |
472 | into STATE and LOOPING worse of the two variants. |
473 | N is the actual node called. */ |
474 | |
475 | static inline void |
476 | worse_state (enum pure_const_state_e *state, bool *looping, |
477 | enum pure_const_state_e state2, bool looping2, |
478 | struct symtab_node *from, |
479 | struct symtab_node *to) |
480 | { |
481 | /* Consider function: |
482 | |
483 | bool a(int *p) |
484 | { |
485 | return *p==*p; |
486 | } |
487 | |
488 | During early optimization we will turn this into: |
489 | |
490 | bool a(int *p) |
491 | { |
492 | return true; |
493 | } |
494 | |
495 | Now if this function will be detected as CONST however when interposed it |
496 | may end up being just pure. We always must assume the worst scenario here. |
497 | */ |
498 | if (*state == IPA_CONST && state2 == IPA_CONST |
499 | && to && !TREE_READONLY (to->decl) && !to->binds_to_current_def_p (ref: from)) |
500 | { |
501 | if (dump_file && (dump_flags & TDF_DETAILS)) |
502 | fprintf (stream: dump_file, format: "Dropping state to PURE because call to %s may not " |
503 | "bind to current def.\n" , to->dump_name ()); |
504 | state2 = IPA_PURE; |
505 | } |
506 | *state = MAX (*state, state2); |
507 | *looping = MAX (*looping, looping2); |
508 | } |
509 | |
510 | /* Recognize special cases of builtins that are by themselves not const |
511 | but function using them is. */ |
512 | bool |
513 | builtin_safe_for_const_function_p (bool *looping, tree callee) |
514 | { |
515 | if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) |
516 | switch (DECL_FUNCTION_CODE (decl: callee)) |
517 | { |
518 | case BUILT_IN_RETURN: |
519 | case BUILT_IN_UNREACHABLE: |
520 | CASE_BUILT_IN_ALLOCA: |
521 | case BUILT_IN_STACK_SAVE: |
522 | case BUILT_IN_STACK_RESTORE: |
523 | case BUILT_IN_EH_POINTER: |
524 | case BUILT_IN_EH_FILTER: |
525 | case BUILT_IN_UNWIND_RESUME: |
526 | case BUILT_IN_CXA_END_CLEANUP: |
527 | case BUILT_IN_EH_COPY_VALUES: |
528 | case BUILT_IN_FRAME_ADDRESS: |
529 | case BUILT_IN_APPLY_ARGS: |
530 | case BUILT_IN_ASAN_BEFORE_DYNAMIC_INIT: |
531 | case BUILT_IN_ASAN_AFTER_DYNAMIC_INIT: |
532 | case BUILT_IN_DWARF_CFA: |
533 | case BUILT_IN_RETURN_ADDRESS: |
534 | *looping = false; |
535 | return true; |
536 | case BUILT_IN_PREFETCH: |
537 | *looping = true; |
538 | return true; |
539 | default: |
540 | break; |
541 | } |
542 | return false; |
543 | } |
544 | |
545 | /* Check the parameters of a function call to CALL_EXPR to see if |
546 | there are any references in the parameters that are not allowed for |
547 | pure or const functions. Also check to see if this is either an |
548 | indirect call, a call outside the compilation unit, or has special |
549 | attributes that may also effect the purity. The CALL_EXPR node for |
550 | the entire call expression. */ |
551 | |
552 | static void |
553 | check_call (funct_state local, gcall *call, bool ipa) |
554 | { |
555 | int flags = gimple_call_flags (call); |
556 | tree callee_t = gimple_call_fndecl (gs: call); |
557 | bool possibly_throws = stmt_could_throw_p (cfun, call); |
558 | bool possibly_throws_externally = (possibly_throws |
559 | && stmt_can_throw_external (cfun, call)); |
560 | |
561 | if (possibly_throws) |
562 | { |
563 | unsigned int i; |
564 | for (i = 0; i < gimple_num_ops (gs: call); i++) |
565 | if (gimple_op (gs: call, i) |
566 | && tree_could_throw_p (gimple_op (gs: call, i))) |
567 | { |
568 | if (possibly_throws && cfun->can_throw_non_call_exceptions) |
569 | { |
570 | if (dump_file) |
571 | fprintf (stream: dump_file, format: " operand can throw; looping\n" ); |
572 | local->looping = true; |
573 | } |
574 | if (possibly_throws_externally) |
575 | { |
576 | if (dump_file) |
577 | fprintf (stream: dump_file, format: " operand can throw externally\n" ); |
578 | local->can_throw = true; |
579 | } |
580 | } |
581 | } |
582 | |
583 | /* The const and pure flags are set by a variety of places in the |
584 | compiler (including here). If someone has already set the flags |
585 | for the callee, (such as for some of the builtins) we will use |
586 | them, otherwise we will compute our own information. |
587 | |
588 | Const and pure functions have less clobber effects than other |
589 | functions so we process these first. Otherwise if it is a call |
590 | outside the compilation unit or an indirect call we punt. This |
591 | leaves local calls which will be processed by following the call |
592 | graph. */ |
593 | if (callee_t) |
594 | { |
595 | bool call_looping; |
596 | |
597 | if (gimple_call_builtin_p (call, BUILT_IN_NORMAL) |
598 | && !nonfreeing_call_p (call)) |
599 | local->can_free = true; |
600 | |
601 | if (builtin_safe_for_const_function_p (looping: &call_looping, callee: callee_t)) |
602 | { |
603 | worse_state (state: &local->pure_const_state, looping: &local->looping, |
604 | state2: IPA_CONST, looping2: call_looping, |
605 | NULL, NULL); |
606 | return; |
607 | } |
608 | /* When bad things happen to bad functions, they cannot be const |
609 | or pure. */ |
610 | if (setjmp_call_p (callee_t)) |
611 | { |
612 | if (dump_file) |
613 | fprintf (stream: dump_file, format: " setjmp is not const/pure\n" ); |
614 | local->looping = true; |
615 | local->pure_const_state = IPA_NEITHER; |
616 | } |
617 | |
618 | if (DECL_BUILT_IN_CLASS (callee_t) == BUILT_IN_NORMAL) |
619 | switch (DECL_FUNCTION_CODE (decl: callee_t)) |
620 | { |
621 | case BUILT_IN_LONGJMP: |
622 | case BUILT_IN_NONLOCAL_GOTO: |
623 | if (dump_file) |
624 | fprintf (stream: dump_file, |
625 | format: " longjmp and nonlocal goto is not const/pure\n" ); |
626 | local->pure_const_state = IPA_NEITHER; |
627 | local->looping = true; |
628 | break; |
629 | default: |
630 | break; |
631 | } |
632 | } |
633 | else if (gimple_call_internal_p (gs: call) && !nonfreeing_call_p (call)) |
634 | local->can_free = true; |
635 | |
636 | /* When not in IPA mode, we can still handle self recursion. */ |
637 | if (!ipa && callee_t |
638 | && recursive_call_p (current_function_decl, callee_t)) |
639 | { |
640 | if (dump_file) |
641 | fprintf (stream: dump_file, format: " Recursive call can loop.\n" ); |
642 | local->looping = true; |
643 | } |
644 | /* Either callee is unknown or we are doing local analysis. |
645 | Look to see if there are any bits available for the callee (such as by |
646 | declaration or because it is builtin) and process solely on the basis of |
647 | those bits. Handle internal calls always, those calls don't have |
648 | corresponding cgraph edges and thus aren't processed during |
649 | the propagation. */ |
650 | else if (!ipa || gimple_call_internal_p (gs: call)) |
651 | { |
652 | enum pure_const_state_e call_state; |
653 | bool call_looping; |
654 | if (possibly_throws && cfun->can_throw_non_call_exceptions) |
655 | { |
656 | if (dump_file) |
657 | fprintf (stream: dump_file, format: " can throw; looping\n" ); |
658 | local->looping = true; |
659 | } |
660 | if (possibly_throws_externally) |
661 | { |
662 | if (dump_file) |
663 | { |
664 | fprintf (stream: dump_file, format: " can throw externally to lp %i\n" , |
665 | lookup_stmt_eh_lp (call)); |
666 | if (callee_t) |
667 | fprintf (stream: dump_file, format: " callee:%s\n" , |
668 | IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (callee_t))); |
669 | } |
670 | local->can_throw = true; |
671 | } |
672 | if (dump_file && (dump_flags & TDF_DETAILS)) |
673 | fprintf (stream: dump_file, format: " checking flags for call:" ); |
674 | state_from_flags (state: &call_state, looping: &call_looping, flags, |
675 | cannot_lead_to_return: ((flags & (ECF_NORETURN | ECF_NOTHROW)) |
676 | == (ECF_NORETURN | ECF_NOTHROW)) |
677 | || (!flag_exceptions && (flags & ECF_NORETURN))); |
678 | worse_state (state: &local->pure_const_state, looping: &local->looping, |
679 | state2: call_state, looping2: call_looping, NULL, NULL); |
680 | } |
681 | /* Direct functions calls are handled by IPA propagation. */ |
682 | } |
683 | |
684 | /* Wrapper around check_decl for loads in local more. */ |
685 | |
686 | static bool |
687 | check_load (gimple *, tree op, tree, void *data) |
688 | { |
689 | if (DECL_P (op)) |
690 | check_decl (local: (funct_state)data, t: op, checking_write: false, ipa: false); |
691 | else |
692 | check_op (local: (funct_state)data, t: op, checking_write: false); |
693 | return false; |
694 | } |
695 | |
696 | /* Wrapper around check_decl for stores in local more. */ |
697 | |
698 | static bool |
699 | check_store (gimple *, tree op, tree, void *data) |
700 | { |
701 | if (DECL_P (op)) |
702 | check_decl (local: (funct_state)data, t: op, checking_write: true, ipa: false); |
703 | else |
704 | check_op (local: (funct_state)data, t: op, checking_write: true); |
705 | return false; |
706 | } |
707 | |
708 | /* Wrapper around check_decl for loads in ipa mode. */ |
709 | |
710 | static bool |
711 | check_ipa_load (gimple *, tree op, tree, void *data) |
712 | { |
713 | if (DECL_P (op)) |
714 | check_decl (local: (funct_state)data, t: op, checking_write: false, ipa: true); |
715 | else |
716 | check_op (local: (funct_state)data, t: op, checking_write: false); |
717 | return false; |
718 | } |
719 | |
720 | /* Wrapper around check_decl for stores in ipa mode. */ |
721 | |
722 | static bool |
723 | check_ipa_store (gimple *, tree op, tree, void *data) |
724 | { |
725 | if (DECL_P (op)) |
726 | check_decl (local: (funct_state)data, t: op, checking_write: true, ipa: true); |
727 | else |
728 | check_op (local: (funct_state)data, t: op, checking_write: true); |
729 | return false; |
730 | } |
731 | |
732 | /* Look into pointer pointed to by GSIP and figure out what interesting side |
733 | effects it has. */ |
734 | static void |
735 | check_stmt (gimple_stmt_iterator *gsip, funct_state local, bool ipa) |
736 | { |
737 | gimple *stmt = gsi_stmt (i: *gsip); |
738 | |
739 | if (is_gimple_debug (gs: stmt)) |
740 | return; |
741 | |
742 | /* Do consider clobber as side effects before IPA, so we rather inline |
743 | C++ destructors and keep clobber semantics than eliminate them. |
744 | |
745 | Similar logic is in ipa-modref. |
746 | |
747 | TODO: We may get smarter during early optimizations on these and let |
748 | functions containing only clobbers to be optimized more. This is a common |
749 | case of C++ destructors. */ |
750 | |
751 | if ((ipa || cfun->after_inlining) && gimple_clobber_p (s: stmt)) |
752 | return; |
753 | |
754 | if (dump_file) |
755 | { |
756 | fprintf (stream: dump_file, format: " scanning: " ); |
757 | print_gimple_stmt (dump_file, stmt, 0); |
758 | } |
759 | |
760 | if (gimple_has_volatile_ops (stmt) |
761 | && !gimple_clobber_p (s: stmt)) |
762 | { |
763 | local->pure_const_state = IPA_NEITHER; |
764 | if (dump_file) |
765 | fprintf (stream: dump_file, format: " Volatile stmt is not const/pure\n" ); |
766 | } |
767 | |
768 | /* Look for loads and stores. */ |
769 | walk_stmt_load_store_ops (stmt, local, |
770 | ipa ? check_ipa_load : check_load, |
771 | ipa ? check_ipa_store : check_store); |
772 | |
773 | if (gimple_code (g: stmt) != GIMPLE_CALL |
774 | && stmt_could_throw_p (cfun, stmt)) |
775 | { |
776 | if (cfun->can_throw_non_call_exceptions) |
777 | { |
778 | if (dump_file) |
779 | fprintf (stream: dump_file, format: " can throw; looping\n" ); |
780 | local->looping = true; |
781 | } |
782 | if (stmt_can_throw_external (cfun, stmt)) |
783 | { |
784 | if (dump_file) |
785 | fprintf (stream: dump_file, format: " can throw externally\n" ); |
786 | local->can_throw = true; |
787 | } |
788 | else |
789 | if (dump_file) |
790 | fprintf (stream: dump_file, format: " can throw\n" ); |
791 | } |
792 | switch (gimple_code (g: stmt)) |
793 | { |
794 | case GIMPLE_CALL: |
795 | check_call (local, call: as_a <gcall *> (p: stmt), ipa); |
796 | break; |
797 | case GIMPLE_LABEL: |
798 | if (DECL_NONLOCAL (gimple_label_label (as_a <glabel *> (stmt)))) |
799 | /* Target of long jump. */ |
800 | { |
801 | if (dump_file) |
802 | fprintf (stream: dump_file, format: " nonlocal label is not const/pure\n" ); |
803 | local->pure_const_state = IPA_NEITHER; |
804 | } |
805 | break; |
806 | case GIMPLE_ASM: |
807 | if (gimple_asm_clobbers_memory_p (as_a <gasm *> (p: stmt))) |
808 | { |
809 | if (dump_file) |
810 | fprintf (stream: dump_file, format: " memory asm clobber is not const/pure\n" ); |
811 | /* Abandon all hope, ye who enter here. */ |
812 | local->pure_const_state = IPA_NEITHER; |
813 | local->can_free = true; |
814 | } |
815 | if (gimple_asm_volatile_p (asm_stmt: as_a <gasm *> (p: stmt))) |
816 | { |
817 | if (dump_file) |
818 | fprintf (stream: dump_file, format: " volatile is not const/pure\n" ); |
819 | /* Abandon all hope, ye who enter here. */ |
820 | local->pure_const_state = IPA_NEITHER; |
821 | local->looping = true; |
822 | local->can_free = true; |
823 | } |
824 | return; |
825 | default: |
826 | break; |
827 | } |
828 | } |
829 | |
830 | /* Check that RETVAL is used only in STMT and in comparisons against 0. |
831 | RETVAL is return value of the function and STMT is return stmt. */ |
832 | |
833 | static bool |
834 | check_retval_uses (tree retval, gimple *stmt) |
835 | { |
836 | imm_use_iterator use_iter; |
837 | gimple *use_stmt; |
838 | |
839 | FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, retval) |
840 | if (gcond *cond = dyn_cast<gcond *> (p: use_stmt)) |
841 | { |
842 | tree op2 = gimple_cond_rhs (gs: cond); |
843 | if (!integer_zerop (op2)) |
844 | return false; |
845 | } |
846 | else if (gassign *ga = dyn_cast<gassign *> (p: use_stmt)) |
847 | { |
848 | enum tree_code code = gimple_assign_rhs_code (gs: ga); |
849 | if (TREE_CODE_CLASS (code) != tcc_comparison) |
850 | return false; |
851 | if (!integer_zerop (gimple_assign_rhs2 (gs: ga))) |
852 | return false; |
853 | } |
854 | else if (is_gimple_debug (gs: use_stmt)) |
855 | ; |
856 | else if (use_stmt != stmt) |
857 | return false; |
858 | |
859 | return true; |
860 | } |
861 | |
862 | /* malloc_candidate_p() checks if FUN can possibly be annotated with malloc |
863 | attribute. Currently this function does a very conservative analysis. |
864 | FUN is considered to be a candidate if |
865 | 1) It returns a value of pointer type. |
866 | 2) SSA_NAME_DEF_STMT (return_value) is either a function call or |
867 | a phi, and element of phi is either NULL or |
868 | SSA_NAME_DEF_STMT(element) is function call. |
869 | 3) The return-value has immediate uses only within comparisons (gcond or gassign) |
870 | and return_stmt (and likewise a phi arg has immediate use only within comparison |
871 | or the phi stmt). */ |
872 | |
873 | #define DUMP_AND_RETURN(reason) \ |
874 | { \ |
875 | if (dump_file && (dump_flags & TDF_DETAILS)) \ |
876 | fprintf (dump_file, "\n%s is not a malloc candidate, reason: %s\n", \ |
877 | (node->dump_name ()), (reason)); \ |
878 | return false; \ |
879 | } |
880 | |
881 | static bool |
882 | malloc_candidate_p_1 (function *fun, tree retval, gimple *ret_stmt, bool ipa, |
883 | bitmap visited) |
884 | { |
885 | cgraph_node *node = cgraph_node::get_create (fun->decl); |
886 | if (!bitmap_set_bit (visited, SSA_NAME_VERSION (retval))) |
887 | return true; |
888 | |
889 | if (!check_retval_uses (retval, stmt: ret_stmt)) |
890 | DUMP_AND_RETURN("Return value has uses outside return stmt" |
891 | " and comparisons against 0." ) |
892 | |
893 | gimple *def = SSA_NAME_DEF_STMT (retval); |
894 | |
895 | if (gcall *call_stmt = dyn_cast<gcall *> (p: def)) |
896 | { |
897 | tree callee_decl = gimple_call_fndecl (gs: call_stmt); |
898 | if (!callee_decl) |
899 | return false; |
900 | |
901 | if (!ipa && !DECL_IS_MALLOC (callee_decl)) |
902 | DUMP_AND_RETURN("callee_decl does not have malloc attribute for" |
903 | " non-ipa mode." ) |
904 | |
905 | cgraph_edge *cs = node->get_edge (call_stmt); |
906 | if (cs) |
907 | { |
908 | ipa_call_summary *es = ipa_call_summaries->get_create (edge: cs); |
909 | es->is_return_callee_uncaptured = true; |
910 | } |
911 | } |
912 | |
913 | else if (gphi *phi = dyn_cast<gphi *> (p: def)) |
914 | { |
915 | bool all_args_zero = true; |
916 | for (unsigned i = 0; i < gimple_phi_num_args (gs: phi); ++i) |
917 | { |
918 | tree arg = gimple_phi_arg_def (gs: phi, index: i); |
919 | if (integer_zerop (arg)) |
920 | continue; |
921 | |
922 | all_args_zero = false; |
923 | if (TREE_CODE (arg) != SSA_NAME) |
924 | DUMP_AND_RETURN ("phi arg is not SSA_NAME." ); |
925 | if (!check_retval_uses (retval: arg, stmt: phi)) |
926 | DUMP_AND_RETURN ("phi arg has uses outside phi" |
927 | " and comparisons against 0." ) |
928 | |
929 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
930 | if (is_a<gphi *> (p: arg_def)) |
931 | { |
932 | if (!malloc_candidate_p_1 (fun, retval: arg, ret_stmt: phi, ipa, visited)) |
933 | DUMP_AND_RETURN ("nested phi fail" ) |
934 | continue; |
935 | } |
936 | |
937 | gcall *call_stmt = dyn_cast<gcall *> (p: arg_def); |
938 | if (!call_stmt) |
939 | DUMP_AND_RETURN ("phi arg is a not a call_stmt." ) |
940 | |
941 | tree callee_decl = gimple_call_fndecl (gs: call_stmt); |
942 | if (!callee_decl) |
943 | return false; |
944 | if (!ipa && !DECL_IS_MALLOC (callee_decl)) |
945 | DUMP_AND_RETURN("callee_decl does not have malloc attribute" |
946 | " for non-ipa mode." ) |
947 | |
948 | cgraph_edge *cs = node->get_edge (call_stmt); |
949 | if (cs) |
950 | { |
951 | ipa_call_summary *es = ipa_call_summaries->get_create (edge: cs); |
952 | es->is_return_callee_uncaptured = true; |
953 | } |
954 | } |
955 | |
956 | if (all_args_zero) |
957 | DUMP_AND_RETURN ("Return value is a phi with all args equal to 0." ) |
958 | } |
959 | |
960 | else |
961 | DUMP_AND_RETURN("def_stmt of return value is not a call or phi-stmt." ) |
962 | |
963 | return true; |
964 | } |
965 | |
966 | static bool |
967 | malloc_candidate_p (function *fun, bool ipa) |
968 | { |
969 | basic_block exit_block = EXIT_BLOCK_PTR_FOR_FN (fun); |
970 | edge e; |
971 | edge_iterator ei; |
972 | cgraph_node *node = cgraph_node::get_create (fun->decl); |
973 | |
974 | if (EDGE_COUNT (exit_block->preds) == 0 |
975 | || !flag_delete_null_pointer_checks) |
976 | return false; |
977 | |
978 | auto_bitmap visited; |
979 | FOR_EACH_EDGE (e, ei, exit_block->preds) |
980 | { |
981 | gimple_stmt_iterator gsi = gsi_last_bb (bb: e->src); |
982 | greturn *ret_stmt = dyn_cast<greturn *> (p: gsi_stmt (i: gsi)); |
983 | |
984 | if (!ret_stmt) |
985 | return false; |
986 | |
987 | tree retval = gimple_return_retval (gs: ret_stmt); |
988 | if (!retval) |
989 | DUMP_AND_RETURN("No return value." ) |
990 | |
991 | if (TREE_CODE (retval) != SSA_NAME |
992 | || TREE_CODE (TREE_TYPE (retval)) != POINTER_TYPE) |
993 | DUMP_AND_RETURN("Return value is not SSA_NAME or not a pointer type." ) |
994 | |
995 | if (!malloc_candidate_p_1 (fun, retval, ret_stmt, ipa, visited)) |
996 | return false; |
997 | } |
998 | |
999 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1000 | fprintf (stream: dump_file, format: "\nFound %s to be candidate for malloc attribute\n" , |
1001 | IDENTIFIER_POINTER (DECL_NAME (fun->decl))); |
1002 | return true; |
1003 | } |
1004 | |
1005 | #undef DUMP_AND_RETURN |
1006 | |
1007 | /* Return true if function is known to be finite. */ |
1008 | |
1009 | bool |
1010 | finite_function_p () |
1011 | { |
1012 | /* Const functions cannot have back edges (an |
1013 | indication of possible infinite loop side |
1014 | effect. */ |
1015 | bool finite = true; |
1016 | if (mark_dfs_back_edges ()) |
1017 | { |
1018 | /* Preheaders are needed for SCEV to work. |
1019 | Simple latches and recorded exits improve chances that loop will |
1020 | proved to be finite in testcases such as in loop-15.c |
1021 | and loop-24.c */ |
1022 | loop_optimizer_init (LOOPS_HAVE_PREHEADERS |
1023 | | LOOPS_HAVE_SIMPLE_LATCHES |
1024 | | LOOPS_HAVE_RECORDED_EXITS); |
1025 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1026 | flow_loops_dump (dump_file, NULL, 0); |
1027 | if (mark_irreducible_loops ()) |
1028 | { |
1029 | if (dump_file) |
1030 | fprintf (stream: dump_file, format: " has irreducible loops\n" ); |
1031 | finite = false; |
1032 | } |
1033 | else |
1034 | { |
1035 | scev_initialize (); |
1036 | for (auto loop : loops_list (cfun, 0)) |
1037 | if (!finite_loop_p (loop)) |
1038 | { |
1039 | if (dump_file) |
1040 | fprintf (stream: dump_file, format: " cannot prove finiteness of " |
1041 | "loop %i\n" , loop->num); |
1042 | finite =false; |
1043 | break; |
1044 | } |
1045 | scev_finalize (); |
1046 | } |
1047 | loop_optimizer_finalize (); |
1048 | } |
1049 | return finite; |
1050 | } |
1051 | |
1052 | /* This is the main routine for finding the reference patterns for |
1053 | global variables within a function FN. */ |
1054 | |
1055 | static funct_state |
1056 | analyze_function (struct cgraph_node *fn, bool ipa) |
1057 | { |
1058 | tree decl = fn->decl; |
1059 | funct_state l; |
1060 | basic_block this_block; |
1061 | |
1062 | l = XCNEW (class funct_state_d); |
1063 | l->pure_const_state = IPA_CONST; |
1064 | l->state_previously_known = IPA_NEITHER; |
1065 | l->looping_previously_known = true; |
1066 | l->looping = false; |
1067 | l->can_throw = false; |
1068 | l->can_free = false; |
1069 | state_from_flags (state: &l->state_previously_known, looping: &l->looping_previously_known, |
1070 | flags: flags_from_decl_or_type (fn->decl), |
1071 | cannot_lead_to_return: fn->cannot_return_p ()); |
1072 | |
1073 | if (fn->thunk || fn->alias) |
1074 | { |
1075 | /* Thunk gets propagated through, so nothing interesting happens. */ |
1076 | gcc_assert (ipa); |
1077 | if (fn->thunk && thunk_info::get (node: fn)->virtual_offset_p) |
1078 | l->pure_const_state = IPA_NEITHER; |
1079 | return l; |
1080 | } |
1081 | |
1082 | if (dump_file) |
1083 | { |
1084 | fprintf (stream: dump_file, format: "\n\n local analysis of %s\n " , |
1085 | fn->dump_name ()); |
1086 | } |
1087 | |
1088 | push_cfun (DECL_STRUCT_FUNCTION (decl)); |
1089 | |
1090 | FOR_EACH_BB_FN (this_block, cfun) |
1091 | { |
1092 | gimple_stmt_iterator gsi; |
1093 | struct walk_stmt_info wi; |
1094 | |
1095 | memset (s: &wi, c: 0, n: sizeof (wi)); |
1096 | for (gsi = gsi_start_bb (bb: this_block); |
1097 | !gsi_end_p (i: gsi); |
1098 | gsi_next (i: &gsi)) |
1099 | { |
1100 | /* NULL memory accesses terminates BB. These accesses are known |
1101 | to trip undefined behaviour. gimple-ssa-isolate-paths turns them |
1102 | to volatile accesses and adds builtin_trap call which would |
1103 | confuse us otherwise. */ |
1104 | if (infer_nonnull_range_by_dereference (gsi_stmt (i: gsi), |
1105 | null_pointer_node)) |
1106 | { |
1107 | if (dump_file) |
1108 | fprintf (stream: dump_file, format: " NULL memory access; terminating BB%s\n" , |
1109 | flag_non_call_exceptions ? "; looping" : "" ); |
1110 | if (flag_non_call_exceptions) |
1111 | { |
1112 | l->looping = true; |
1113 | if (stmt_can_throw_external (cfun, gsi_stmt (i: gsi))) |
1114 | { |
1115 | if (dump_file) |
1116 | fprintf (stream: dump_file, format: " can throw externally\n" ); |
1117 | l->can_throw = true; |
1118 | } |
1119 | } |
1120 | break; |
1121 | } |
1122 | check_stmt (gsip: &gsi, local: l, ipa); |
1123 | if (l->pure_const_state == IPA_NEITHER |
1124 | && l->looping |
1125 | && l->can_throw |
1126 | && l->can_free) |
1127 | goto end; |
1128 | } |
1129 | } |
1130 | |
1131 | end: |
1132 | if (l->pure_const_state != IPA_NEITHER |
1133 | && !l->looping |
1134 | && !finite_function_p ()) |
1135 | l->looping = true; |
1136 | |
1137 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1138 | fprintf (stream: dump_file, format: " checking previously known:" ); |
1139 | |
1140 | better_state (state: &l->pure_const_state, looping: &l->looping, |
1141 | state2: l->state_previously_known, |
1142 | looping2: l->looping_previously_known); |
1143 | if (TREE_NOTHROW (decl)) |
1144 | l->can_throw = false; |
1145 | |
1146 | l->malloc_state = STATE_MALLOC_BOTTOM; |
1147 | if (DECL_IS_MALLOC (decl)) |
1148 | l->malloc_state = STATE_MALLOC; |
1149 | else if (ipa && malloc_candidate_p (DECL_STRUCT_FUNCTION (decl), ipa: true)) |
1150 | l->malloc_state = STATE_MALLOC_TOP; |
1151 | else if (malloc_candidate_p (DECL_STRUCT_FUNCTION (decl), ipa: false)) |
1152 | l->malloc_state = STATE_MALLOC; |
1153 | |
1154 | pop_cfun (); |
1155 | if (dump_file) |
1156 | { |
1157 | if (l->looping) |
1158 | fprintf (stream: dump_file, format: "Function is locally looping.\n" ); |
1159 | if (l->can_throw) |
1160 | fprintf (stream: dump_file, format: "Function is locally throwing.\n" ); |
1161 | if (l->pure_const_state == IPA_CONST) |
1162 | fprintf (stream: dump_file, format: "Function is locally const.\n" ); |
1163 | if (l->pure_const_state == IPA_PURE) |
1164 | fprintf (stream: dump_file, format: "Function is locally pure.\n" ); |
1165 | if (l->can_free) |
1166 | fprintf (stream: dump_file, format: "Function can locally free.\n" ); |
1167 | if (l->malloc_state == STATE_MALLOC) |
1168 | fprintf (stream: dump_file, format: "Function is locally malloc.\n" ); |
1169 | } |
1170 | return l; |
1171 | } |
1172 | |
1173 | void |
1174 | funct_state_summary_t::insert (cgraph_node *node, funct_state_d *state) |
1175 | { |
1176 | /* There are some shared nodes, in particular the initializers on |
1177 | static declarations. We do not need to scan them more than once |
1178 | since all we would be interested in are the addressof |
1179 | operations. */ |
1180 | if (opt_for_fn (node->decl, flag_ipa_pure_const)) |
1181 | { |
1182 | funct_state_d *a = analyze_function (fn: node, ipa: true); |
1183 | new (state) funct_state_d (*a); |
1184 | free (ptr: a); |
1185 | } |
1186 | else |
1187 | /* Do not keep stale summaries. */ |
1188 | funct_state_summaries->remove (node); |
1189 | } |
1190 | |
1191 | /* Called when new clone is inserted to callgraph late. */ |
1192 | |
1193 | void |
1194 | funct_state_summary_t::duplicate (cgraph_node *, cgraph_node *dst, |
1195 | funct_state_d *src_data, |
1196 | funct_state_d *dst_data) |
1197 | { |
1198 | new (dst_data) funct_state_d (*src_data); |
1199 | if (dst_data->malloc_state == STATE_MALLOC |
1200 | && VOID_TYPE_P (TREE_TYPE (TREE_TYPE (dst->decl)))) |
1201 | dst_data->malloc_state = STATE_MALLOC_BOTTOM; |
1202 | } |
1203 | |
1204 | |
1205 | void |
1206 | pass_ipa_pure_const:: |
1207 | register_hooks (void) |
1208 | { |
1209 | if (init_p) |
1210 | return; |
1211 | |
1212 | init_p = true; |
1213 | |
1214 | funct_state_summaries = new funct_state_summary_t (symtab); |
1215 | } |
1216 | |
1217 | |
1218 | /* Analyze each function in the cgraph to see if it is locally PURE or |
1219 | CONST. */ |
1220 | |
1221 | static void |
1222 | pure_const_generate_summary (void) |
1223 | { |
1224 | struct cgraph_node *node; |
1225 | |
1226 | pass_ipa_pure_const *pass = static_cast <pass_ipa_pure_const *> (current_pass); |
1227 | pass->register_hooks (); |
1228 | |
1229 | /* Process all of the functions. |
1230 | |
1231 | We process AVAIL_INTERPOSABLE functions. We cannot use the results |
1232 | by default, but the info can be used at LTO with -fwhole-program or |
1233 | when function got cloned and the clone is AVAILABLE. */ |
1234 | |
1235 | FOR_EACH_DEFINED_FUNCTION (node) |
1236 | if (opt_for_fn (node->decl, flag_ipa_pure_const)) |
1237 | { |
1238 | funct_state_d *a = analyze_function (fn: node, ipa: true); |
1239 | new (funct_state_summaries->get_create (node)) funct_state_d (*a); |
1240 | free (ptr: a); |
1241 | } |
1242 | } |
1243 | |
1244 | |
1245 | /* Serialize the ipa info for lto. */ |
1246 | |
1247 | static void |
1248 | pure_const_write_summary (void) |
1249 | { |
1250 | struct cgraph_node *node; |
1251 | struct lto_simple_output_block *ob |
1252 | = lto_create_simple_output_block (LTO_section_ipa_pure_const); |
1253 | unsigned int count = 0; |
1254 | lto_symtab_encoder_iterator lsei; |
1255 | lto_symtab_encoder_t encoder; |
1256 | |
1257 | encoder = lto_get_out_decl_state ()->symtab_node_encoder; |
1258 | |
1259 | for (lsei = lsei_start_function_in_partition (encoder); !lsei_end_p (lsei); |
1260 | lsei_next_function_in_partition (lsei: &lsei)) |
1261 | { |
1262 | node = lsei_cgraph_node (lsei); |
1263 | if (node->definition && funct_state_summaries->exists (node)) |
1264 | count++; |
1265 | } |
1266 | |
1267 | streamer_write_uhwi_stream (ob->main_stream, count); |
1268 | |
1269 | /* Process all of the functions. */ |
1270 | for (lsei = lsei_start_function_in_partition (encoder); !lsei_end_p (lsei); |
1271 | lsei_next_function_in_partition (lsei: &lsei)) |
1272 | { |
1273 | node = lsei_cgraph_node (lsei); |
1274 | funct_state_d *fs = funct_state_summaries->get (node); |
1275 | if (node->definition && fs != NULL) |
1276 | { |
1277 | struct bitpack_d bp; |
1278 | int node_ref; |
1279 | lto_symtab_encoder_t encoder; |
1280 | |
1281 | encoder = ob->decl_state->symtab_node_encoder; |
1282 | node_ref = lto_symtab_encoder_encode (encoder, node); |
1283 | streamer_write_uhwi_stream (ob->main_stream, node_ref); |
1284 | |
1285 | /* Note that flags will need to be read in the opposite |
1286 | order as we are pushing the bitflags into FLAGS. */ |
1287 | bp = bitpack_create (s: ob->main_stream); |
1288 | bp_pack_value (bp: &bp, val: fs->pure_const_state, nbits: 2); |
1289 | bp_pack_value (bp: &bp, val: fs->state_previously_known, nbits: 2); |
1290 | bp_pack_value (bp: &bp, val: fs->looping_previously_known, nbits: 1); |
1291 | bp_pack_value (bp: &bp, val: fs->looping, nbits: 1); |
1292 | bp_pack_value (bp: &bp, val: fs->can_throw, nbits: 1); |
1293 | bp_pack_value (bp: &bp, val: fs->can_free, nbits: 1); |
1294 | bp_pack_value (bp: &bp, val: fs->malloc_state, nbits: 2); |
1295 | streamer_write_bitpack (bp: &bp); |
1296 | } |
1297 | } |
1298 | |
1299 | lto_destroy_simple_output_block (ob); |
1300 | } |
1301 | |
1302 | |
1303 | /* Deserialize the ipa info for lto. */ |
1304 | |
1305 | static void |
1306 | pure_const_read_summary (void) |
1307 | { |
1308 | struct lto_file_decl_data **file_data_vec = lto_get_file_decl_data (); |
1309 | struct lto_file_decl_data *file_data; |
1310 | unsigned int j = 0; |
1311 | |
1312 | pass_ipa_pure_const *pass = static_cast <pass_ipa_pure_const *> (current_pass); |
1313 | pass->register_hooks (); |
1314 | |
1315 | while ((file_data = file_data_vec[j++])) |
1316 | { |
1317 | const char *data; |
1318 | size_t len; |
1319 | class lto_input_block *ib |
1320 | = lto_create_simple_input_block (file_data, |
1321 | LTO_section_ipa_pure_const, |
1322 | &data, &len); |
1323 | if (ib) |
1324 | { |
1325 | unsigned int i; |
1326 | unsigned int count = streamer_read_uhwi (ib); |
1327 | |
1328 | for (i = 0; i < count; i++) |
1329 | { |
1330 | unsigned int index; |
1331 | struct cgraph_node *node; |
1332 | struct bitpack_d bp; |
1333 | funct_state fs; |
1334 | lto_symtab_encoder_t encoder; |
1335 | |
1336 | index = streamer_read_uhwi (ib); |
1337 | encoder = file_data->symtab_node_encoder; |
1338 | node = dyn_cast<cgraph_node *> (p: lto_symtab_encoder_deref (encoder, |
1339 | ref: index)); |
1340 | |
1341 | fs = funct_state_summaries->get_create (node); |
1342 | /* Note that the flags must be read in the opposite |
1343 | order in which they were written (the bitflags were |
1344 | pushed into FLAGS). */ |
1345 | bp = streamer_read_bitpack (ib); |
1346 | fs->pure_const_state |
1347 | = (enum pure_const_state_e) bp_unpack_value (bp: &bp, nbits: 2); |
1348 | fs->state_previously_known |
1349 | = (enum pure_const_state_e) bp_unpack_value (bp: &bp, nbits: 2); |
1350 | fs->looping_previously_known = bp_unpack_value (bp: &bp, nbits: 1); |
1351 | fs->looping = bp_unpack_value (bp: &bp, nbits: 1); |
1352 | fs->can_throw = bp_unpack_value (bp: &bp, nbits: 1); |
1353 | fs->can_free = bp_unpack_value (bp: &bp, nbits: 1); |
1354 | fs->malloc_state |
1355 | = (enum malloc_state_e) bp_unpack_value (bp: &bp, nbits: 2); |
1356 | |
1357 | if (dump_file) |
1358 | { |
1359 | int flags = flags_from_decl_or_type (node->decl); |
1360 | fprintf (stream: dump_file, format: "Read info for %s " , node->dump_name ()); |
1361 | if (flags & ECF_CONST) |
1362 | fprintf (stream: dump_file, format: " const" ); |
1363 | if (flags & ECF_PURE) |
1364 | fprintf (stream: dump_file, format: " pure" ); |
1365 | if (flags & ECF_NOTHROW) |
1366 | fprintf (stream: dump_file, format: " nothrow" ); |
1367 | fprintf (stream: dump_file, format: "\n pure const state: %s\n" , |
1368 | pure_const_names[fs->pure_const_state]); |
1369 | fprintf (stream: dump_file, format: " previously known state: %s\n" , |
1370 | pure_const_names[fs->state_previously_known]); |
1371 | if (fs->looping) |
1372 | fprintf (stream: dump_file,format: " function is locally looping\n" ); |
1373 | if (fs->looping_previously_known) |
1374 | fprintf (stream: dump_file,format: " function is previously known looping\n" ); |
1375 | if (fs->can_throw) |
1376 | fprintf (stream: dump_file,format: " function is locally throwing\n" ); |
1377 | if (fs->can_free) |
1378 | fprintf (stream: dump_file,format: " function can locally free\n" ); |
1379 | fprintf (stream: dump_file, format: "\n malloc state: %s\n" , |
1380 | malloc_state_names[fs->malloc_state]); |
1381 | } |
1382 | } |
1383 | |
1384 | lto_destroy_simple_input_block (file_data, |
1385 | LTO_section_ipa_pure_const, |
1386 | ib, data, len); |
1387 | } |
1388 | } |
1389 | } |
1390 | |
1391 | /* We only propagate across edges that can throw externally and their callee |
1392 | is not interposable. */ |
1393 | |
1394 | static bool |
1395 | ignore_edge_for_nothrow (struct cgraph_edge *e) |
1396 | { |
1397 | if (!e->can_throw_external || TREE_NOTHROW (e->callee->decl)) |
1398 | return true; |
1399 | |
1400 | enum availability avail; |
1401 | cgraph_node *ultimate_target |
1402 | = e->callee->function_or_virtual_thunk_symbol (avail: &avail, ref: e->caller); |
1403 | if (avail <= AVAIL_INTERPOSABLE || TREE_NOTHROW (ultimate_target->decl)) |
1404 | return true; |
1405 | return ((opt_for_fn (e->callee->decl, flag_non_call_exceptions) |
1406 | && !e->callee->binds_to_current_def_p (ref: e->caller)) |
1407 | || !opt_for_fn (e->caller->decl, flag_ipa_pure_const) |
1408 | || !opt_for_fn (ultimate_target->decl, flag_ipa_pure_const)); |
1409 | } |
1410 | |
1411 | /* Return true if NODE is self recursive function. |
1412 | Indirectly recursive functions appears as non-trivial strongly |
1413 | connected components, so we need to care about self recursion |
1414 | only. */ |
1415 | |
1416 | static bool |
1417 | self_recursive_p (struct cgraph_node *node) |
1418 | { |
1419 | struct cgraph_edge *e; |
1420 | for (e = node->callees; e; e = e->next_callee) |
1421 | if (e->callee->function_symbol () == node) |
1422 | return true; |
1423 | return false; |
1424 | } |
1425 | |
1426 | /* Return true if N is cdtor that is not const or pure. In this case we may |
1427 | need to remove unreachable function if it is marked const/pure. */ |
1428 | |
1429 | static bool |
1430 | cdtor_p (cgraph_node *n, void *) |
1431 | { |
1432 | if (DECL_STATIC_CONSTRUCTOR (n->decl) || DECL_STATIC_DESTRUCTOR (n->decl)) |
1433 | return ((!TREE_READONLY (n->decl) && !DECL_PURE_P (n->decl)) |
1434 | || DECL_LOOPING_CONST_OR_PURE_P (n->decl)); |
1435 | return false; |
1436 | } |
1437 | |
1438 | /* Skip edges from and to nodes without ipa_pure_const enabled. |
1439 | Ignore not available symbols. */ |
1440 | |
1441 | static bool |
1442 | ignore_edge_for_pure_const (struct cgraph_edge *e) |
1443 | { |
1444 | enum availability avail; |
1445 | cgraph_node *ultimate_target |
1446 | = e->callee->function_or_virtual_thunk_symbol (avail: &avail, ref: e->caller); |
1447 | |
1448 | return (avail <= AVAIL_INTERPOSABLE |
1449 | || !opt_for_fn (e->caller->decl, flag_ipa_pure_const) |
1450 | || !opt_for_fn (ultimate_target->decl, |
1451 | flag_ipa_pure_const)); |
1452 | } |
1453 | |
1454 | /* Return true if function should be skipped for local pure const analysis. */ |
1455 | |
1456 | static bool |
1457 | skip_function_for_local_pure_const (struct cgraph_node *node) |
1458 | { |
1459 | /* Because we do not schedule pass_fixup_cfg over whole program after early |
1460 | optimizations we must not promote functions that are called by already |
1461 | processed functions. */ |
1462 | |
1463 | if (function_called_by_processed_nodes_p ()) |
1464 | { |
1465 | if (dump_file) |
1466 | fprintf (stream: dump_file, format: "Function called in recursive cycle; ignoring\n" ); |
1467 | return true; |
1468 | } |
1469 | /* Save some work and do not analyze functions which are interposable and |
1470 | do not have any non-interposable aliases. */ |
1471 | if (node->get_availability () <= AVAIL_INTERPOSABLE |
1472 | && !flag_lto |
1473 | && !node->has_aliases_p ()) |
1474 | { |
1475 | if (dump_file) |
1476 | fprintf (stream: dump_file, |
1477 | format: "Function is interposable; not analyzing.\n" ); |
1478 | return true; |
1479 | } |
1480 | return false; |
1481 | } |
1482 | |
1483 | /* Make function const and output warning. If LOCAL is true, |
1484 | return true if anything changed. Otherwise return true if |
1485 | we may have introduced removale ctors. */ |
1486 | |
1487 | bool |
1488 | ipa_make_function_const (struct cgraph_node *node, bool looping, bool local) |
1489 | { |
1490 | bool cdtor = false; |
1491 | |
1492 | if (TREE_READONLY (node->decl) |
1493 | && (looping || !DECL_LOOPING_CONST_OR_PURE_P (node->decl))) |
1494 | return false; |
1495 | warn_function_const (decl: node->decl, known_finite: !looping); |
1496 | if (local && skip_function_for_local_pure_const (node)) |
1497 | return false; |
1498 | if (dump_file) |
1499 | fprintf (stream: dump_file, format: "Function found to be %sconst: %s\n" , |
1500 | looping ? "looping " : "" , |
1501 | node->dump_name ()); |
1502 | if (!local && !looping) |
1503 | cdtor = node->call_for_symbol_and_aliases (callback: cdtor_p, NULL, include_overwritable: true); |
1504 | if (!dbg_cnt (index: ipa_attr)) |
1505 | return false; |
1506 | if (node->set_const_flag (set_const: true, looping)) |
1507 | { |
1508 | if (dump_file) |
1509 | fprintf (stream: dump_file, |
1510 | format: "Declaration updated to be %sconst: %s\n" , |
1511 | looping ? "looping " : "" , |
1512 | node->dump_name ()); |
1513 | if (local) |
1514 | return true; |
1515 | return cdtor; |
1516 | } |
1517 | return false; |
1518 | } |
1519 | |
1520 | /* Make function const and output warning. If LOCAL is true, |
1521 | return true if anything changed. Otherwise return true if |
1522 | we may have introduced removale ctors. */ |
1523 | |
1524 | bool |
1525 | ipa_make_function_pure (struct cgraph_node *node, bool looping, bool local) |
1526 | { |
1527 | bool cdtor = false; |
1528 | |
1529 | if (TREE_READONLY (node->decl) |
1530 | || (DECL_PURE_P (node->decl) |
1531 | && (looping || !DECL_LOOPING_CONST_OR_PURE_P (node->decl)))) |
1532 | return false; |
1533 | warn_function_pure (decl: node->decl, known_finite: !looping); |
1534 | if (local && skip_function_for_local_pure_const (node)) |
1535 | return false; |
1536 | if (dump_file) |
1537 | fprintf (stream: dump_file, format: "Function found to be %spure: %s\n" , |
1538 | looping ? "looping " : "" , |
1539 | node->dump_name ()); |
1540 | if (!local && !looping) |
1541 | cdtor = node->call_for_symbol_and_aliases (callback: cdtor_p, NULL, include_overwritable: true); |
1542 | if (!dbg_cnt (index: ipa_attr)) |
1543 | return false; |
1544 | if (node->set_pure_flag (pure: true, looping)) |
1545 | { |
1546 | if (dump_file) |
1547 | fprintf (stream: dump_file, |
1548 | format: "Declaration updated to be %spure: %s\n" , |
1549 | looping ? "looping " : "" , |
1550 | node->dump_name ()); |
1551 | if (local) |
1552 | return true; |
1553 | return cdtor; |
1554 | } |
1555 | return false; |
1556 | } |
1557 | |
1558 | /* Produce transitive closure over the callgraph and compute pure/const |
1559 | attributes. */ |
1560 | |
1561 | static bool |
1562 | propagate_pure_const (void) |
1563 | { |
1564 | struct cgraph_node *node; |
1565 | struct cgraph_node *w; |
1566 | struct cgraph_node **order = |
1567 | XCNEWVEC (struct cgraph_node *, symtab->cgraph_count); |
1568 | int order_pos; |
1569 | int i; |
1570 | struct ipa_dfs_info * w_info; |
1571 | bool remove_p = false; |
1572 | |
1573 | order_pos = ipa_reduced_postorder (order, true, |
1574 | ignore_edge: ignore_edge_for_pure_const); |
1575 | if (dump_file) |
1576 | { |
1577 | cgraph_node::dump_cgraph (f: dump_file); |
1578 | ipa_print_order (dump_file, "reduced" , order, order_pos); |
1579 | } |
1580 | |
1581 | /* Propagate the local information through the call graph to produce |
1582 | the global information. All the nodes within a cycle will have |
1583 | the same info so we collapse cycles first. Then we can do the |
1584 | propagation in one pass from the leaves to the roots. */ |
1585 | for (i = 0; i < order_pos; i++ ) |
1586 | { |
1587 | enum pure_const_state_e pure_const_state = IPA_CONST; |
1588 | bool looping = false; |
1589 | int count = 0; |
1590 | node = order[i]; |
1591 | |
1592 | if (node->alias) |
1593 | continue; |
1594 | |
1595 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1596 | fprintf (stream: dump_file, format: "Starting cycle\n" ); |
1597 | |
1598 | /* Find the worst state for any node in the cycle. */ |
1599 | w = node; |
1600 | while (w && pure_const_state != IPA_NEITHER) |
1601 | { |
1602 | struct cgraph_edge *e; |
1603 | struct cgraph_edge *ie; |
1604 | int i; |
1605 | struct ipa_ref *ref = NULL; |
1606 | |
1607 | funct_state w_l = funct_state_summaries->get_create (node: w); |
1608 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1609 | fprintf (stream: dump_file, format: " Visiting %s state:%s looping %i\n" , |
1610 | w->dump_name (), |
1611 | pure_const_names[w_l->pure_const_state], |
1612 | w_l->looping); |
1613 | |
1614 | /* First merge in function body properties. |
1615 | We are safe to pass NULL as FROM and TO because we will take care |
1616 | of possible interposition when walking callees. */ |
1617 | worse_state (state: &pure_const_state, looping: &looping, |
1618 | state2: w_l->pure_const_state, looping2: w_l->looping, |
1619 | NULL, NULL); |
1620 | if (pure_const_state == IPA_NEITHER) |
1621 | break; |
1622 | |
1623 | count++; |
1624 | |
1625 | /* We consider recursive cycles as possibly infinite. |
1626 | This might be relaxed since infinite recursion leads to stack |
1627 | overflow. */ |
1628 | if (count > 1) |
1629 | looping = true; |
1630 | |
1631 | /* Now walk the edges and merge in callee properties. */ |
1632 | for (e = w->callees; e && pure_const_state != IPA_NEITHER; |
1633 | e = e->next_callee) |
1634 | { |
1635 | enum availability avail; |
1636 | struct cgraph_node *y = e->callee-> |
1637 | function_or_virtual_thunk_symbol (avail: &avail, |
1638 | ref: e->caller); |
1639 | enum pure_const_state_e edge_state = IPA_CONST; |
1640 | bool edge_looping = false; |
1641 | |
1642 | if (e->recursive_p ()) |
1643 | looping = true; |
1644 | |
1645 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1646 | { |
1647 | fprintf (stream: dump_file, format: " Call to %s" , |
1648 | e->callee->dump_name ()); |
1649 | } |
1650 | if (avail > AVAIL_INTERPOSABLE) |
1651 | { |
1652 | funct_state y_l = funct_state_summaries->get_create (node: y); |
1653 | |
1654 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1655 | { |
1656 | fprintf (stream: dump_file, |
1657 | format: " state:%s looping:%i\n" , |
1658 | pure_const_names[y_l->pure_const_state], |
1659 | y_l->looping); |
1660 | } |
1661 | if (y_l->pure_const_state > IPA_PURE |
1662 | && e->cannot_lead_to_return_p ()) |
1663 | { |
1664 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1665 | fprintf (stream: dump_file, |
1666 | format: " Ignoring side effects" |
1667 | " -> pure, looping\n" ); |
1668 | edge_state = IPA_PURE; |
1669 | edge_looping = true; |
1670 | } |
1671 | else |
1672 | { |
1673 | edge_state = y_l->pure_const_state; |
1674 | edge_looping = y_l->looping; |
1675 | } |
1676 | } |
1677 | else if (builtin_safe_for_const_function_p (looping: &edge_looping, |
1678 | callee: y->decl)) |
1679 | edge_state = IPA_CONST; |
1680 | else |
1681 | state_from_flags (state: &edge_state, looping: &edge_looping, |
1682 | flags: flags_from_decl_or_type (y->decl), |
1683 | cannot_lead_to_return: e->cannot_lead_to_return_p ()); |
1684 | |
1685 | /* Merge the results with what we already know. */ |
1686 | better_state (state: &edge_state, looping: &edge_looping, |
1687 | state2: w_l->state_previously_known, |
1688 | looping2: w_l->looping_previously_known); |
1689 | worse_state (state: &pure_const_state, looping: &looping, |
1690 | state2: edge_state, looping2: edge_looping, from: e->caller, to: e->callee); |
1691 | if (pure_const_state == IPA_NEITHER) |
1692 | break; |
1693 | } |
1694 | |
1695 | /* Now process the indirect call. */ |
1696 | for (ie = w->indirect_calls; |
1697 | ie && pure_const_state != IPA_NEITHER; ie = ie->next_callee) |
1698 | { |
1699 | enum pure_const_state_e edge_state = IPA_CONST; |
1700 | bool edge_looping = false; |
1701 | |
1702 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1703 | fprintf (stream: dump_file, format: " Indirect call" ); |
1704 | state_from_flags (state: &edge_state, looping: &edge_looping, |
1705 | flags: ie->indirect_info->ecf_flags, |
1706 | cannot_lead_to_return: ie->cannot_lead_to_return_p ()); |
1707 | /* Merge the results with what we already know. */ |
1708 | better_state (state: &edge_state, looping: &edge_looping, |
1709 | state2: w_l->state_previously_known, |
1710 | looping2: w_l->looping_previously_known); |
1711 | worse_state (state: &pure_const_state, looping: &looping, |
1712 | state2: edge_state, looping2: edge_looping, NULL, NULL); |
1713 | if (pure_const_state == IPA_NEITHER) |
1714 | break; |
1715 | } |
1716 | |
1717 | /* And finally all loads and stores. */ |
1718 | for (i = 0; w->iterate_reference (i, ref) |
1719 | && pure_const_state != IPA_NEITHER; i++) |
1720 | { |
1721 | enum pure_const_state_e ref_state = IPA_CONST; |
1722 | bool ref_looping = false; |
1723 | switch (ref->use) |
1724 | { |
1725 | case IPA_REF_LOAD: |
1726 | /* readonly reads are safe. */ |
1727 | if (TREE_READONLY (ref->referred->decl)) |
1728 | break; |
1729 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1730 | fprintf (stream: dump_file, format: " nonreadonly global var read\n" ); |
1731 | ref_state = IPA_PURE; |
1732 | break; |
1733 | case IPA_REF_STORE: |
1734 | if (ref->cannot_lead_to_return ()) |
1735 | break; |
1736 | ref_state = IPA_NEITHER; |
1737 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1738 | fprintf (stream: dump_file, format: " global var write\n" ); |
1739 | break; |
1740 | case IPA_REF_ADDR: |
1741 | break; |
1742 | default: |
1743 | gcc_unreachable (); |
1744 | } |
1745 | better_state (state: &ref_state, looping: &ref_looping, |
1746 | state2: w_l->state_previously_known, |
1747 | looping2: w_l->looping_previously_known); |
1748 | worse_state (state: &pure_const_state, looping: &looping, |
1749 | state2: ref_state, looping2: ref_looping, NULL, NULL); |
1750 | if (pure_const_state == IPA_NEITHER) |
1751 | break; |
1752 | } |
1753 | w_info = (struct ipa_dfs_info *) w->aux; |
1754 | w = w_info->next_cycle; |
1755 | } |
1756 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1757 | fprintf (stream: dump_file, format: "Result %s looping %i\n" , |
1758 | pure_const_names [pure_const_state], |
1759 | looping); |
1760 | |
1761 | /* Find the worst state of can_free for any node in the cycle. */ |
1762 | bool can_free = false; |
1763 | w = node; |
1764 | while (w && !can_free) |
1765 | { |
1766 | struct cgraph_edge *e; |
1767 | funct_state w_l = funct_state_summaries->get (node: w); |
1768 | |
1769 | if (w_l->can_free |
1770 | || w->get_availability () == AVAIL_INTERPOSABLE |
1771 | || w->indirect_calls) |
1772 | can_free = true; |
1773 | |
1774 | for (e = w->callees; e && !can_free; e = e->next_callee) |
1775 | { |
1776 | enum availability avail; |
1777 | struct cgraph_node *y = e->callee-> |
1778 | function_or_virtual_thunk_symbol (avail: &avail, |
1779 | ref: e->caller); |
1780 | |
1781 | if (avail > AVAIL_INTERPOSABLE) |
1782 | can_free = funct_state_summaries->get (node: y)->can_free; |
1783 | else |
1784 | can_free = true; |
1785 | } |
1786 | w_info = (struct ipa_dfs_info *) w->aux; |
1787 | w = w_info->next_cycle; |
1788 | } |
1789 | |
1790 | /* Copy back the region's pure_const_state which is shared by |
1791 | all nodes in the region. */ |
1792 | w = node; |
1793 | while (w) |
1794 | { |
1795 | funct_state w_l = funct_state_summaries->get (node: w); |
1796 | enum pure_const_state_e this_state = pure_const_state; |
1797 | bool this_looping = looping; |
1798 | |
1799 | w_l->can_free = can_free; |
1800 | w->nonfreeing_fn = !can_free; |
1801 | if (!can_free && dump_file) |
1802 | fprintf (stream: dump_file, format: "Function found not to call free: %s\n" , |
1803 | w->dump_name ()); |
1804 | |
1805 | if (w_l->state_previously_known != IPA_NEITHER |
1806 | && this_state > w_l->state_previously_known) |
1807 | { |
1808 | if (this_state == IPA_NEITHER) |
1809 | this_looping = w_l->looping_previously_known; |
1810 | this_state = w_l->state_previously_known; |
1811 | } |
1812 | if (!this_looping && self_recursive_p (node: w)) |
1813 | this_looping = true; |
1814 | if (!w_l->looping_previously_known) |
1815 | this_looping = false; |
1816 | |
1817 | /* All nodes within a cycle share the same info. */ |
1818 | w_l->pure_const_state = this_state; |
1819 | w_l->looping = this_looping; |
1820 | |
1821 | /* Inline clones share declaration with their offline copies; |
1822 | do not modify their declarations since the offline copy may |
1823 | be different. */ |
1824 | if (!w->inlined_to) |
1825 | switch (this_state) |
1826 | { |
1827 | case IPA_CONST: |
1828 | remove_p |= ipa_make_function_const (node: w, looping: this_looping, local: false); |
1829 | break; |
1830 | |
1831 | case IPA_PURE: |
1832 | remove_p |= ipa_make_function_pure (node: w, looping: this_looping, local: false); |
1833 | break; |
1834 | |
1835 | default: |
1836 | break; |
1837 | } |
1838 | w_info = (struct ipa_dfs_info *) w->aux; |
1839 | w = w_info->next_cycle; |
1840 | } |
1841 | } |
1842 | |
1843 | ipa_free_postorder_info (); |
1844 | free (ptr: order); |
1845 | return remove_p; |
1846 | } |
1847 | |
1848 | /* Produce transitive closure over the callgraph and compute nothrow |
1849 | attributes. */ |
1850 | |
1851 | static void |
1852 | propagate_nothrow (void) |
1853 | { |
1854 | struct cgraph_node *node; |
1855 | struct cgraph_node *w; |
1856 | struct cgraph_node **order = |
1857 | XCNEWVEC (struct cgraph_node *, symtab->cgraph_count); |
1858 | int order_pos; |
1859 | int i; |
1860 | struct ipa_dfs_info * w_info; |
1861 | |
1862 | order_pos = ipa_reduced_postorder (order, true, |
1863 | ignore_edge: ignore_edge_for_nothrow); |
1864 | if (dump_file) |
1865 | { |
1866 | cgraph_node::dump_cgraph (f: dump_file); |
1867 | ipa_print_order (dump_file, "reduced for nothrow" , order, order_pos); |
1868 | } |
1869 | |
1870 | /* Propagate the local information through the call graph to produce |
1871 | the global information. All the nodes within a cycle will have |
1872 | the same info so we collapse cycles first. Then we can do the |
1873 | propagation in one pass from the leaves to the roots. */ |
1874 | for (i = 0; i < order_pos; i++ ) |
1875 | { |
1876 | bool can_throw = false; |
1877 | node = order[i]; |
1878 | |
1879 | if (node->alias) |
1880 | continue; |
1881 | |
1882 | /* Find the worst state for any node in the cycle. */ |
1883 | w = node; |
1884 | while (w && !can_throw) |
1885 | { |
1886 | struct cgraph_edge *e, *ie; |
1887 | |
1888 | if (!TREE_NOTHROW (w->decl)) |
1889 | { |
1890 | funct_state w_l = funct_state_summaries->get_create (node: w); |
1891 | |
1892 | if (w_l->can_throw |
1893 | || w->get_availability () == AVAIL_INTERPOSABLE) |
1894 | can_throw = true; |
1895 | |
1896 | for (e = w->callees; e && !can_throw; e = e->next_callee) |
1897 | { |
1898 | enum availability avail; |
1899 | |
1900 | if (!e->can_throw_external || TREE_NOTHROW (e->callee->decl)) |
1901 | continue; |
1902 | |
1903 | struct cgraph_node *y = e->callee-> |
1904 | function_or_virtual_thunk_symbol (avail: &avail, |
1905 | ref: e->caller); |
1906 | |
1907 | /* We can use info about the callee only if we know it |
1908 | cannot be interposed. |
1909 | When callee is compiled with non-call exceptions we also |
1910 | must check that the declaration is bound to current |
1911 | body as other semantically equivalent body may still |
1912 | throw. */ |
1913 | if (avail <= AVAIL_INTERPOSABLE |
1914 | || (!TREE_NOTHROW (y->decl) |
1915 | && (funct_state_summaries->get_create (node: y)->can_throw |
1916 | || (opt_for_fn (y->decl, flag_non_call_exceptions) |
1917 | && !e->callee->binds_to_current_def_p (ref: w))))) |
1918 | can_throw = true; |
1919 | } |
1920 | for (ie = w->indirect_calls; ie && !can_throw; |
1921 | ie = ie->next_callee) |
1922 | if (ie->can_throw_external |
1923 | && !(ie->indirect_info->ecf_flags & ECF_NOTHROW)) |
1924 | can_throw = true; |
1925 | } |
1926 | w_info = (struct ipa_dfs_info *) w->aux; |
1927 | w = w_info->next_cycle; |
1928 | } |
1929 | |
1930 | /* Copy back the region's pure_const_state which is shared by |
1931 | all nodes in the region. */ |
1932 | w = node; |
1933 | while (w) |
1934 | { |
1935 | funct_state w_l = funct_state_summaries->get_create (node: w); |
1936 | if (!can_throw && !TREE_NOTHROW (w->decl)) |
1937 | { |
1938 | /* Inline clones share declaration with their offline copies; |
1939 | do not modify their declarations since the offline copy may |
1940 | be different. */ |
1941 | if (!w->inlined_to) |
1942 | { |
1943 | w->set_nothrow_flag (true); |
1944 | if (dump_file) |
1945 | fprintf (stream: dump_file, format: "Function found to be nothrow: %s\n" , |
1946 | w->dump_name ()); |
1947 | } |
1948 | } |
1949 | else if (can_throw && !TREE_NOTHROW (w->decl)) |
1950 | w_l->can_throw = true; |
1951 | w_info = (struct ipa_dfs_info *) w->aux; |
1952 | w = w_info->next_cycle; |
1953 | } |
1954 | } |
1955 | |
1956 | ipa_free_postorder_info (); |
1957 | free (ptr: order); |
1958 | } |
1959 | |
1960 | /* Debugging function to dump state of malloc lattice. */ |
1961 | |
1962 | DEBUG_FUNCTION |
1963 | static void |
1964 | dump_malloc_lattice (FILE *dump_file, const char *s) |
1965 | { |
1966 | if (!dump_file) |
1967 | return; |
1968 | |
1969 | fprintf (stream: dump_file, format: "\n\nMALLOC LATTICE %s:\n" , s); |
1970 | cgraph_node *node; |
1971 | FOR_EACH_FUNCTION (node) |
1972 | { |
1973 | funct_state fs = funct_state_summaries->get (node); |
1974 | if (fs) |
1975 | fprintf (stream: dump_file, format: "%s: %s\n" , node->dump_name (), |
1976 | malloc_state_names[fs->malloc_state]); |
1977 | } |
1978 | } |
1979 | |
1980 | /* Propagate malloc attribute across the callgraph. */ |
1981 | |
1982 | static void |
1983 | propagate_malloc (void) |
1984 | { |
1985 | cgraph_node *node; |
1986 | FOR_EACH_FUNCTION (node) |
1987 | { |
1988 | if (DECL_IS_MALLOC (node->decl)) |
1989 | if (!funct_state_summaries->exists (node)) |
1990 | { |
1991 | funct_state fs = funct_state_summaries->get_create (node); |
1992 | fs->malloc_state = STATE_MALLOC; |
1993 | } |
1994 | } |
1995 | |
1996 | dump_malloc_lattice (dump_file, s: "Initial" ); |
1997 | struct cgraph_node **order |
1998 | = XNEWVEC (struct cgraph_node *, symtab->cgraph_count); |
1999 | int order_pos = ipa_reverse_postorder (order); |
2000 | bool changed = true; |
2001 | |
2002 | while (changed) |
2003 | { |
2004 | changed = false; |
2005 | /* Walk in postorder. */ |
2006 | for (int i = order_pos - 1; i >= 0; --i) |
2007 | { |
2008 | cgraph_node *node = order[i]; |
2009 | if (node->alias |
2010 | || !node->definition |
2011 | || !funct_state_summaries->exists (node)) |
2012 | continue; |
2013 | |
2014 | funct_state l = funct_state_summaries->get (node); |
2015 | |
2016 | /* FIXME: add support for indirect-calls. */ |
2017 | if (node->indirect_calls) |
2018 | { |
2019 | l->malloc_state = STATE_MALLOC_BOTTOM; |
2020 | continue; |
2021 | } |
2022 | |
2023 | if (node->get_availability () <= AVAIL_INTERPOSABLE) |
2024 | { |
2025 | l->malloc_state = STATE_MALLOC_BOTTOM; |
2026 | continue; |
2027 | } |
2028 | |
2029 | if (l->malloc_state == STATE_MALLOC_BOTTOM) |
2030 | continue; |
2031 | |
2032 | auto_vec<cgraph_node *, 16> callees; |
2033 | for (cgraph_edge *cs = node->callees; cs; cs = cs->next_callee) |
2034 | { |
2035 | ipa_call_summary *es = ipa_call_summaries->get_create (edge: cs); |
2036 | if (es && es->is_return_callee_uncaptured) |
2037 | callees.safe_push (obj: cs->callee); |
2038 | } |
2039 | |
2040 | malloc_state_e new_state = l->malloc_state; |
2041 | for (unsigned j = 0; j < callees.length (); j++) |
2042 | { |
2043 | cgraph_node *callee = callees[j]; |
2044 | if (!funct_state_summaries->exists (node)) |
2045 | { |
2046 | new_state = STATE_MALLOC_BOTTOM; |
2047 | break; |
2048 | } |
2049 | malloc_state_e callee_state |
2050 | = funct_state_summaries->get_create (node: callee)->malloc_state; |
2051 | if (new_state < callee_state) |
2052 | new_state = callee_state; |
2053 | } |
2054 | if (new_state != l->malloc_state) |
2055 | { |
2056 | changed = true; |
2057 | l->malloc_state = new_state; |
2058 | } |
2059 | } |
2060 | } |
2061 | |
2062 | FOR_EACH_DEFINED_FUNCTION (node) |
2063 | if (funct_state_summaries->exists (node)) |
2064 | { |
2065 | funct_state l = funct_state_summaries->get (node); |
2066 | if (!node->alias |
2067 | && l->malloc_state == STATE_MALLOC |
2068 | && !node->inlined_to |
2069 | && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (node->decl)))) |
2070 | { |
2071 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2072 | fprintf (stream: dump_file, format: "Function %s found to be malloc\n" , |
2073 | node->dump_name ()); |
2074 | |
2075 | bool malloc_decl_p = DECL_IS_MALLOC (node->decl); |
2076 | node->set_malloc_flag (true); |
2077 | if (!malloc_decl_p && warn_suggest_attribute_malloc) |
2078 | warn_function_malloc (decl: node->decl); |
2079 | } |
2080 | } |
2081 | |
2082 | dump_malloc_lattice (dump_file, s: "after propagation" ); |
2083 | ipa_free_postorder_info (); |
2084 | free (ptr: order); |
2085 | } |
2086 | |
2087 | /* Produce the global information by preforming a transitive closure |
2088 | on the local information that was produced by generate_summary. */ |
2089 | |
2090 | unsigned int |
2091 | pass_ipa_pure_const:: |
2092 | execute (function *) |
2093 | { |
2094 | bool remove_p; |
2095 | |
2096 | /* Nothrow makes more function to not lead to return and improve |
2097 | later analysis. */ |
2098 | propagate_nothrow (); |
2099 | propagate_malloc (); |
2100 | remove_p = propagate_pure_const (); |
2101 | |
2102 | delete funct_state_summaries; |
2103 | return remove_p ? TODO_remove_functions : 0; |
2104 | } |
2105 | |
2106 | static bool |
2107 | gate_pure_const (void) |
2108 | { |
2109 | return flag_ipa_pure_const || in_lto_p; |
2110 | } |
2111 | |
2112 | pass_ipa_pure_const::pass_ipa_pure_const(gcc::context *ctxt) |
2113 | : ipa_opt_pass_d(pass_data_ipa_pure_const, ctxt, |
2114 | pure_const_generate_summary, /* generate_summary */ |
2115 | pure_const_write_summary, /* write_summary */ |
2116 | pure_const_read_summary, /* read_summary */ |
2117 | NULL, /* write_optimization_summary */ |
2118 | NULL, /* read_optimization_summary */ |
2119 | NULL, /* stmt_fixup */ |
2120 | 0, /* function_transform_todo_flags_start */ |
2121 | NULL, /* function_transform */ |
2122 | NULL), /* variable_transform */ |
2123 | init_p (false) {} |
2124 | |
2125 | ipa_opt_pass_d * |
2126 | make_pass_ipa_pure_const (gcc::context *ctxt) |
2127 | { |
2128 | return new pass_ipa_pure_const (ctxt); |
2129 | } |
2130 | |
2131 | /* Simple local pass for pure const discovery reusing the analysis from |
2132 | ipa_pure_const. This pass is effective when executed together with |
2133 | other optimization passes in early optimization pass queue. */ |
2134 | |
2135 | namespace { |
2136 | |
2137 | const pass_data pass_data_local_pure_const = |
2138 | { |
2139 | .type: GIMPLE_PASS, /* type */ |
2140 | .name: "local-pure-const" , /* name */ |
2141 | .optinfo_flags: OPTGROUP_NONE, /* optinfo_flags */ |
2142 | .tv_id: TV_IPA_PURE_CONST, /* tv_id */ |
2143 | .properties_required: 0, /* properties_required */ |
2144 | .properties_provided: 0, /* properties_provided */ |
2145 | .properties_destroyed: 0, /* properties_destroyed */ |
2146 | .todo_flags_start: 0, /* todo_flags_start */ |
2147 | .todo_flags_finish: 0, /* todo_flags_finish */ |
2148 | }; |
2149 | |
2150 | class pass_local_pure_const : public gimple_opt_pass |
2151 | { |
2152 | public: |
2153 | pass_local_pure_const (gcc::context *ctxt) |
2154 | : gimple_opt_pass (pass_data_local_pure_const, ctxt) |
2155 | {} |
2156 | |
2157 | /* opt_pass methods: */ |
2158 | opt_pass * clone () final override |
2159 | { |
2160 | return new pass_local_pure_const (m_ctxt); |
2161 | } |
2162 | bool gate (function *) final override { return gate_pure_const (); } |
2163 | unsigned int execute (function *) final override; |
2164 | |
2165 | }; // class pass_local_pure_const |
2166 | |
2167 | unsigned int |
2168 | pass_local_pure_const::execute (function *fun) |
2169 | { |
2170 | bool changed = false; |
2171 | funct_state l; |
2172 | bool skip; |
2173 | struct cgraph_node *node; |
2174 | |
2175 | node = cgraph_node::get (decl: current_function_decl); |
2176 | skip = skip_function_for_local_pure_const (node); |
2177 | |
2178 | if (!warn_suggest_attribute_const |
2179 | && !warn_suggest_attribute_pure |
2180 | && skip) |
2181 | return 0; |
2182 | |
2183 | l = analyze_function (fn: node, ipa: false); |
2184 | |
2185 | /* Do NORETURN discovery. */ |
2186 | if (!skip && !TREE_THIS_VOLATILE (current_function_decl) |
2187 | && EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (fun)->preds) == 0) |
2188 | { |
2189 | warn_function_noreturn (decl: fun->decl); |
2190 | if (dump_file) |
2191 | fprintf (stream: dump_file, format: "Function found to be noreturn: %s\n" , |
2192 | current_function_name ()); |
2193 | |
2194 | /* Update declaration and reduce profile to executed once. */ |
2195 | if (cgraph_node::get (decl: current_function_decl)->set_noreturn_flag (true)) |
2196 | changed = true; |
2197 | if (node->frequency > NODE_FREQUENCY_EXECUTED_ONCE) |
2198 | node->frequency = NODE_FREQUENCY_EXECUTED_ONCE; |
2199 | } |
2200 | |
2201 | switch (l->pure_const_state) |
2202 | { |
2203 | case IPA_CONST: |
2204 | changed |= ipa_make_function_const |
2205 | (node: cgraph_node::get (decl: current_function_decl), looping: l->looping, local: true); |
2206 | break; |
2207 | |
2208 | case IPA_PURE: |
2209 | changed |= ipa_make_function_pure |
2210 | (node: cgraph_node::get (decl: current_function_decl), looping: l->looping, local: true); |
2211 | break; |
2212 | |
2213 | default: |
2214 | break; |
2215 | } |
2216 | if (!l->can_throw && !TREE_NOTHROW (current_function_decl)) |
2217 | { |
2218 | node->set_nothrow_flag (true); |
2219 | changed = true; |
2220 | if (dump_file) |
2221 | fprintf (stream: dump_file, format: "Function found to be nothrow: %s\n" , |
2222 | current_function_name ()); |
2223 | } |
2224 | |
2225 | if (l->malloc_state == STATE_MALLOC |
2226 | && !DECL_IS_MALLOC (current_function_decl)) |
2227 | { |
2228 | node->set_malloc_flag (true); |
2229 | if (warn_suggest_attribute_malloc) |
2230 | warn_function_malloc (decl: node->decl); |
2231 | changed = true; |
2232 | if (dump_file) |
2233 | fprintf (stream: dump_file, format: "Function found to be malloc: %s\n" , |
2234 | node->dump_name ()); |
2235 | } |
2236 | |
2237 | free (ptr: l); |
2238 | if (changed) |
2239 | return execute_fixup_cfg (); |
2240 | else |
2241 | return 0; |
2242 | } |
2243 | |
2244 | } // anon namespace |
2245 | |
2246 | gimple_opt_pass * |
2247 | make_pass_local_pure_const (gcc::context *ctxt) |
2248 | { |
2249 | return new pass_local_pure_const (ctxt); |
2250 | } |
2251 | |
2252 | /* Emit noreturn warnings. */ |
2253 | |
2254 | namespace { |
2255 | |
2256 | const pass_data pass_data_warn_function_noreturn = |
2257 | { |
2258 | .type: GIMPLE_PASS, /* type */ |
2259 | .name: "*warn_function_noreturn" , /* name */ |
2260 | .optinfo_flags: OPTGROUP_NONE, /* optinfo_flags */ |
2261 | .tv_id: TV_NONE, /* tv_id */ |
2262 | PROP_cfg, /* properties_required */ |
2263 | .properties_provided: 0, /* properties_provided */ |
2264 | .properties_destroyed: 0, /* properties_destroyed */ |
2265 | .todo_flags_start: 0, /* todo_flags_start */ |
2266 | .todo_flags_finish: 0, /* todo_flags_finish */ |
2267 | }; |
2268 | |
2269 | class pass_warn_function_noreturn : public gimple_opt_pass |
2270 | { |
2271 | public: |
2272 | pass_warn_function_noreturn (gcc::context *ctxt) |
2273 | : gimple_opt_pass (pass_data_warn_function_noreturn, ctxt) |
2274 | {} |
2275 | |
2276 | /* opt_pass methods: */ |
2277 | bool gate (function *) final override |
2278 | { |
2279 | return warn_suggest_attribute_noreturn; |
2280 | } |
2281 | unsigned int execute (function *fun) final override |
2282 | { |
2283 | if (!TREE_THIS_VOLATILE (current_function_decl) |
2284 | && EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (fun)->preds) == 0) |
2285 | warn_function_noreturn (decl: current_function_decl); |
2286 | return 0; |
2287 | } |
2288 | |
2289 | }; // class pass_warn_function_noreturn |
2290 | |
2291 | } // anon namespace |
2292 | |
2293 | gimple_opt_pass * |
2294 | make_pass_warn_function_noreturn (gcc::context *ctxt) |
2295 | { |
2296 | return new pass_warn_function_noreturn (ctxt); |
2297 | } |
2298 | |
2299 | /* Simple local pass for pure const discovery reusing the analysis from |
2300 | ipa_pure_const. This pass is effective when executed together with |
2301 | other optimization passes in early optimization pass queue. */ |
2302 | |
2303 | namespace { |
2304 | |
2305 | const pass_data pass_data_nothrow = |
2306 | { |
2307 | .type: GIMPLE_PASS, /* type */ |
2308 | .name: "nothrow" , /* name */ |
2309 | .optinfo_flags: OPTGROUP_NONE, /* optinfo_flags */ |
2310 | .tv_id: TV_IPA_PURE_CONST, /* tv_id */ |
2311 | .properties_required: 0, /* properties_required */ |
2312 | .properties_provided: 0, /* properties_provided */ |
2313 | .properties_destroyed: 0, /* properties_destroyed */ |
2314 | .todo_flags_start: 0, /* todo_flags_start */ |
2315 | .todo_flags_finish: 0, /* todo_flags_finish */ |
2316 | }; |
2317 | |
2318 | class pass_nothrow : public gimple_opt_pass |
2319 | { |
2320 | public: |
2321 | pass_nothrow (gcc::context *ctxt) |
2322 | : gimple_opt_pass (pass_data_nothrow, ctxt) |
2323 | {} |
2324 | |
2325 | /* opt_pass methods: */ |
2326 | opt_pass * clone () final override { return new pass_nothrow (m_ctxt); } |
2327 | bool gate (function *) final override { return optimize; } |
2328 | unsigned int execute (function *) final override; |
2329 | |
2330 | }; // class pass_nothrow |
2331 | |
2332 | unsigned int |
2333 | pass_nothrow::execute (function *) |
2334 | { |
2335 | struct cgraph_node *node; |
2336 | basic_block this_block; |
2337 | |
2338 | if (TREE_NOTHROW (current_function_decl)) |
2339 | return 0; |
2340 | |
2341 | node = cgraph_node::get (decl: current_function_decl); |
2342 | |
2343 | /* We run during lowering, we cannot really use availability yet. */ |
2344 | if (cgraph_node::get (decl: current_function_decl)->get_availability () |
2345 | <= AVAIL_INTERPOSABLE) |
2346 | { |
2347 | if (dump_file) |
2348 | fprintf (stream: dump_file, format: "Function is interposable;" |
2349 | " not analyzing.\n" ); |
2350 | return true; |
2351 | } |
2352 | |
2353 | FOR_EACH_BB_FN (this_block, cfun) |
2354 | { |
2355 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb: this_block); |
2356 | !gsi_end_p (i: gsi); |
2357 | gsi_next (i: &gsi)) |
2358 | if (stmt_can_throw_external (cfun, gsi_stmt (i: gsi))) |
2359 | { |
2360 | if (is_gimple_call (gs: gsi_stmt (i: gsi))) |
2361 | { |
2362 | tree callee_t = gimple_call_fndecl (gs: gsi_stmt (i: gsi)); |
2363 | if (callee_t && recursive_call_p (current_function_decl, |
2364 | callee_t)) |
2365 | continue; |
2366 | } |
2367 | |
2368 | if (dump_file) |
2369 | { |
2370 | fprintf (stream: dump_file, format: "Statement can throw: " ); |
2371 | print_gimple_stmt (dump_file, gsi_stmt (i: gsi), 0); |
2372 | } |
2373 | return 0; |
2374 | } |
2375 | } |
2376 | |
2377 | node->set_nothrow_flag (true); |
2378 | |
2379 | bool cfg_changed = false; |
2380 | if (self_recursive_p (node)) |
2381 | FOR_EACH_BB_FN (this_block, cfun) |
2382 | if (gcall *g = safe_dyn_cast <gcall *> (p: *gsi_last_bb (bb: this_block))) |
2383 | { |
2384 | tree callee_t = gimple_call_fndecl (gs: g); |
2385 | if (callee_t |
2386 | && recursive_call_p (current_function_decl, callee_t) |
2387 | && maybe_clean_eh_stmt (g) |
2388 | && gimple_purge_dead_eh_edges (this_block)) |
2389 | cfg_changed = true; |
2390 | } |
2391 | |
2392 | if (dump_file) |
2393 | fprintf (stream: dump_file, format: "Function found to be nothrow: %s\n" , |
2394 | current_function_name ()); |
2395 | return cfg_changed ? TODO_cleanup_cfg : 0; |
2396 | } |
2397 | |
2398 | } // anon namespace |
2399 | |
2400 | gimple_opt_pass * |
2401 | make_pass_nothrow (gcc::context *ctxt) |
2402 | { |
2403 | return new pass_nothrow (ctxt); |
2404 | } |
2405 | |