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06cefae9 | 1 | /* Optimize and expand sanitizer functions. |
cbe34bb5 | 2 | Copyright (C) 2014-2017 Free Software Foundation, Inc. |
06cefae9 MP |
3 | Contributed by Marek Polacek <polacek@redhat.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 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
c7131fb2 | 24 | #include "backend.h" |
06cefae9 | 25 | #include "tree.h" |
c7131fb2 | 26 | #include "gimple.h" |
2f75d6eb | 27 | #include "ssa.h" |
957060b5 | 28 | #include "tree-pass.h" |
957060b5 AM |
29 | #include "tree-ssa-operands.h" |
30 | #include "gimple-pretty-print.h" | |
c7131fb2 | 31 | #include "fold-const.h" |
06cefae9 | 32 | #include "gimple-iterator.h" |
314e6352 ML |
33 | #include "stringpool.h" |
34 | #include "attribs.h" | |
06cefae9 | 35 | #include "asan.h" |
06cefae9 MP |
36 | #include "ubsan.h" |
37 | #include "params.h" | |
d6a818c5 | 38 | #include "tree-hash-traits.h" |
94087e88 JJ |
39 | #include "gimple-ssa.h" |
40 | #include "tree-phinodes.h" | |
41 | #include "ssa-iterators.h" | |
da402967 ML |
42 | #include "gimplify.h" |
43 | #include "gimple-iterator.h" | |
44 | #include "gimple-walk.h" | |
45 | #include "cfghooks.h" | |
46 | #include "tree-dfa.h" | |
47 | #include "tree-ssa.h" | |
513d5564 | 48 | #include "varasm.h" |
06cefae9 | 49 | |
06cefae9 MP |
50 | /* This is used to carry information about basic blocks. It is |
51 | attached to the AUX field of the standard CFG block. */ | |
52 | ||
53 | struct sanopt_info | |
54 | { | |
ab9a4330 JJ |
55 | /* True if this BB might call (directly or indirectly) free/munmap |
56 | or similar operation. */ | |
57 | bool has_freeing_call_p; | |
58 | ||
59 | /* True if HAS_FREEING_CALL_P flag has been computed. */ | |
60 | bool has_freeing_call_computed_p; | |
61 | ||
62 | /* True if there is a block with HAS_FREEING_CALL_P flag set | |
63 | on any path between an immediate dominator of BB, denoted | |
64 | imm(BB), and BB. */ | |
65 | bool imm_dom_path_with_freeing_call_p; | |
66 | ||
67 | /* True if IMM_DOM_PATH_WITH_FREEING_CALL_P has been computed. */ | |
68 | bool imm_dom_path_with_freeing_call_computed_p; | |
69 | ||
70 | /* Number of possibly freeing calls encountered in this bb | |
71 | (so far). */ | |
72 | uint64_t freeing_call_events; | |
73 | ||
74 | /* True if BB is currently being visited during computation | |
75 | of IMM_DOM_PATH_WITH_FREEING_CALL_P flag. */ | |
76 | bool being_visited_p; | |
77 | ||
78 | /* True if this BB has been visited in the dominator walk. */ | |
06cefae9 MP |
79 | bool visited_p; |
80 | }; | |
81 | ||
e28f2090 YG |
82 | /* If T has a single definition of form T = T2, return T2. */ |
83 | ||
84 | static tree | |
85 | maybe_get_single_definition (tree t) | |
86 | { | |
87 | if (TREE_CODE (t) == SSA_NAME) | |
88 | { | |
355fe088 | 89 | gimple *g = SSA_NAME_DEF_STMT (t); |
e28f2090 YG |
90 | if (gimple_assign_single_p (g)) |
91 | return gimple_assign_rhs1 (g); | |
92 | } | |
93 | return NULL_TREE; | |
94 | } | |
95 | ||
35228ac7 JJ |
96 | /* Tree triplet for vptr_check_map. */ |
97 | struct sanopt_tree_triplet | |
98 | { | |
99 | tree t1, t2, t3; | |
100 | }; | |
101 | ||
102 | /* Traits class for tree triplet hash maps below. */ | |
103 | ||
9654754b | 104 | struct sanopt_tree_triplet_hash : typed_noop_remove <sanopt_tree_triplet> |
35228ac7 | 105 | { |
9654754b RS |
106 | typedef sanopt_tree_triplet value_type; |
107 | typedef sanopt_tree_triplet compare_type; | |
108 | ||
513d5564 | 109 | static hashval_t |
35228ac7 JJ |
110 | hash (const sanopt_tree_triplet &ref) |
111 | { | |
112 | inchash::hash hstate (0); | |
113 | inchash::add_expr (ref.t1, hstate); | |
114 | inchash::add_expr (ref.t2, hstate); | |
115 | inchash::add_expr (ref.t3, hstate); | |
116 | return hstate.end (); | |
117 | } | |
118 | ||
513d5564 | 119 | static bool |
9654754b | 120 | equal (const sanopt_tree_triplet &ref1, const sanopt_tree_triplet &ref2) |
35228ac7 JJ |
121 | { |
122 | return operand_equal_p (ref1.t1, ref2.t1, 0) | |
123 | && operand_equal_p (ref1.t2, ref2.t2, 0) | |
124 | && operand_equal_p (ref1.t3, ref2.t3, 0); | |
125 | } | |
126 | ||
513d5564 | 127 | static void |
9654754b | 128 | mark_deleted (sanopt_tree_triplet &ref) |
35228ac7 | 129 | { |
9654754b | 130 | ref.t1 = reinterpret_cast<tree> (1); |
35228ac7 JJ |
131 | } |
132 | ||
513d5564 | 133 | static void |
9654754b | 134 | mark_empty (sanopt_tree_triplet &ref) |
35228ac7 | 135 | { |
9654754b | 136 | ref.t1 = NULL; |
35228ac7 JJ |
137 | } |
138 | ||
513d5564 | 139 | static bool |
9654754b | 140 | is_deleted (const sanopt_tree_triplet &ref) |
35228ac7 | 141 | { |
513d5564 | 142 | return ref.t1 == reinterpret_cast<tree> (1); |
35228ac7 JJ |
143 | } |
144 | ||
513d5564 | 145 | static bool |
9654754b | 146 | is_empty (const sanopt_tree_triplet &ref) |
35228ac7 | 147 | { |
9654754b | 148 | return ref.t1 == NULL; |
35228ac7 JJ |
149 | } |
150 | }; | |
151 | ||
513d5564 ML |
152 | /* Tree couple for ptr_check_map. */ |
153 | struct sanopt_tree_couple | |
154 | { | |
155 | tree ptr; | |
156 | bool pos_p; | |
157 | }; | |
158 | ||
159 | /* Traits class for tree triplet hash maps below. */ | |
160 | ||
161 | struct sanopt_tree_couple_hash : typed_noop_remove <sanopt_tree_couple> | |
162 | { | |
163 | typedef sanopt_tree_couple value_type; | |
164 | typedef sanopt_tree_couple compare_type; | |
165 | ||
166 | static hashval_t | |
167 | hash (const sanopt_tree_couple &ref) | |
168 | { | |
169 | inchash::hash hstate (0); | |
170 | inchash::add_expr (ref.ptr, hstate); | |
171 | hstate.add_int (ref.pos_p); | |
172 | return hstate.end (); | |
173 | } | |
174 | ||
175 | static bool | |
176 | equal (const sanopt_tree_couple &ref1, const sanopt_tree_couple &ref2) | |
177 | { | |
178 | return operand_equal_p (ref1.ptr, ref2.ptr, 0) | |
179 | && ref1.pos_p == ref2.pos_p; | |
180 | } | |
181 | ||
182 | static void | |
183 | mark_deleted (sanopt_tree_couple &ref) | |
184 | { | |
185 | ref.ptr = reinterpret_cast<tree> (1); | |
186 | } | |
187 | ||
188 | static void | |
189 | mark_empty (sanopt_tree_couple &ref) | |
190 | { | |
191 | ref.ptr = NULL; | |
192 | } | |
193 | ||
194 | static bool | |
195 | is_deleted (const sanopt_tree_couple &ref) | |
196 | { | |
197 | return ref.ptr == reinterpret_cast<tree> (1); | |
198 | } | |
199 | ||
200 | static bool | |
201 | is_empty (const sanopt_tree_couple &ref) | |
202 | { | |
203 | return ref.ptr == NULL; | |
204 | } | |
205 | }; | |
206 | ||
06cefae9 MP |
207 | /* This is used to carry various hash maps and variables used |
208 | in sanopt_optimize_walker. */ | |
209 | ||
210 | struct sanopt_ctx | |
211 | { | |
212 | /* This map maps a pointer (the first argument of UBSAN_NULL) to | |
213 | a vector of UBSAN_NULL call statements that check this pointer. */ | |
355fe088 | 214 | hash_map<tree, auto_vec<gimple *> > null_check_map; |
06cefae9 | 215 | |
ab9a4330 JJ |
216 | /* This map maps a pointer (the second argument of ASAN_CHECK) to |
217 | a vector of ASAN_CHECK call statements that check the access. */ | |
355fe088 | 218 | hash_map<tree_operand_hash, auto_vec<gimple *> > asan_check_map; |
35228ac7 JJ |
219 | |
220 | /* This map maps a tree triplet (the first, second and fourth argument | |
221 | of UBSAN_VPTR) to a vector of UBSAN_VPTR call statements that check | |
222 | that virtual table pointer. */ | |
355fe088 | 223 | hash_map<sanopt_tree_triplet_hash, auto_vec<gimple *> > vptr_check_map; |
ab9a4330 | 224 | |
513d5564 ML |
225 | /* This map maps a couple (tree and boolean) to a vector of UBSAN_PTR |
226 | call statements that check that pointer overflow. */ | |
227 | hash_map<sanopt_tree_couple_hash, auto_vec<gimple *> > ptr_check_map; | |
228 | ||
06cefae9 MP |
229 | /* Number of IFN_ASAN_CHECK statements. */ |
230 | int asan_num_accesses; | |
06cefae9 | 231 | |
2f75d6eb ML |
232 | /* True when the current functions constains an ASAN_MARK. */ |
233 | bool contains_asan_mark; | |
234 | }; | |
06cefae9 | 235 | |
ab9a4330 JJ |
236 | /* Return true if there might be any call to free/munmap operation |
237 | on any path in between DOM (which should be imm(BB)) and BB. */ | |
238 | ||
239 | static bool | |
240 | imm_dom_path_with_freeing_call (basic_block bb, basic_block dom) | |
241 | { | |
242 | sanopt_info *info = (sanopt_info *) bb->aux; | |
243 | edge e; | |
244 | edge_iterator ei; | |
245 | ||
246 | if (info->imm_dom_path_with_freeing_call_computed_p) | |
247 | return info->imm_dom_path_with_freeing_call_p; | |
248 | ||
249 | info->being_visited_p = true; | |
250 | ||
251 | FOR_EACH_EDGE (e, ei, bb->preds) | |
252 | { | |
253 | sanopt_info *pred_info = (sanopt_info *) e->src->aux; | |
254 | ||
255 | if (e->src == dom) | |
256 | continue; | |
257 | ||
258 | if ((pred_info->imm_dom_path_with_freeing_call_computed_p | |
259 | && pred_info->imm_dom_path_with_freeing_call_p) | |
260 | || (pred_info->has_freeing_call_computed_p | |
261 | && pred_info->has_freeing_call_p)) | |
262 | { | |
263 | info->imm_dom_path_with_freeing_call_computed_p = true; | |
264 | info->imm_dom_path_with_freeing_call_p = true; | |
265 | info->being_visited_p = false; | |
266 | return true; | |
267 | } | |
268 | } | |
269 | ||
270 | FOR_EACH_EDGE (e, ei, bb->preds) | |
271 | { | |
272 | sanopt_info *pred_info = (sanopt_info *) e->src->aux; | |
273 | ||
274 | if (e->src == dom) | |
275 | continue; | |
276 | ||
277 | if (pred_info->has_freeing_call_computed_p) | |
278 | continue; | |
279 | ||
280 | gimple_stmt_iterator gsi; | |
281 | for (gsi = gsi_start_bb (e->src); !gsi_end_p (gsi); gsi_next (&gsi)) | |
282 | { | |
355fe088 | 283 | gimple *stmt = gsi_stmt (gsi); |
8e104951 | 284 | gasm *asm_stmt; |
ab9a4330 | 285 | |
8e104951 ML |
286 | if ((is_gimple_call (stmt) && !nonfreeing_call_p (stmt)) |
287 | || ((asm_stmt = dyn_cast <gasm *> (stmt)) | |
288 | && (gimple_asm_clobbers_memory_p (asm_stmt) | |
289 | || gimple_asm_volatile_p (asm_stmt)))) | |
ab9a4330 JJ |
290 | { |
291 | pred_info->has_freeing_call_p = true; | |
292 | break; | |
293 | } | |
294 | } | |
295 | ||
296 | pred_info->has_freeing_call_computed_p = true; | |
297 | if (pred_info->has_freeing_call_p) | |
298 | { | |
299 | info->imm_dom_path_with_freeing_call_computed_p = true; | |
300 | info->imm_dom_path_with_freeing_call_p = true; | |
301 | info->being_visited_p = false; | |
302 | return true; | |
303 | } | |
304 | } | |
305 | ||
306 | FOR_EACH_EDGE (e, ei, bb->preds) | |
307 | { | |
308 | if (e->src == dom) | |
309 | continue; | |
310 | ||
311 | basic_block src; | |
312 | for (src = e->src; src != dom; ) | |
313 | { | |
314 | sanopt_info *pred_info = (sanopt_info *) src->aux; | |
315 | if (pred_info->being_visited_p) | |
316 | break; | |
317 | basic_block imm = get_immediate_dominator (CDI_DOMINATORS, src); | |
318 | if (imm_dom_path_with_freeing_call (src, imm)) | |
319 | { | |
320 | info->imm_dom_path_with_freeing_call_computed_p = true; | |
321 | info->imm_dom_path_with_freeing_call_p = true; | |
322 | info->being_visited_p = false; | |
323 | return true; | |
324 | } | |
325 | src = imm; | |
326 | } | |
327 | } | |
328 | ||
329 | info->imm_dom_path_with_freeing_call_computed_p = true; | |
330 | info->imm_dom_path_with_freeing_call_p = false; | |
331 | info->being_visited_p = false; | |
332 | return false; | |
333 | } | |
334 | ||
e28f2090 YG |
335 | /* Get the first dominating check from the list of stored checks. |
336 | Non-dominating checks are silently dropped. */ | |
337 | ||
355fe088 TS |
338 | static gimple * |
339 | maybe_get_dominating_check (auto_vec<gimple *> &v) | |
e28f2090 YG |
340 | { |
341 | for (; !v.is_empty (); v.pop ()) | |
342 | { | |
355fe088 | 343 | gimple *g = v.last (); |
e28f2090 YG |
344 | sanopt_info *si = (sanopt_info *) gimple_bb (g)->aux; |
345 | if (!si->visited_p) | |
346 | /* At this point we shouldn't have any statements | |
347 | that aren't dominating the current BB. */ | |
348 | return g; | |
349 | } | |
350 | return NULL; | |
351 | } | |
352 | ||
ab9a4330 JJ |
353 | /* Optimize away redundant UBSAN_NULL calls. */ |
354 | ||
355 | static bool | |
355fe088 | 356 | maybe_optimize_ubsan_null_ifn (struct sanopt_ctx *ctx, gimple *stmt) |
ab9a4330 JJ |
357 | { |
358 | gcc_assert (gimple_call_num_args (stmt) == 3); | |
359 | tree ptr = gimple_call_arg (stmt, 0); | |
360 | tree cur_align = gimple_call_arg (stmt, 2); | |
361 | gcc_assert (TREE_CODE (cur_align) == INTEGER_CST); | |
362 | bool remove = false; | |
363 | ||
355fe088 TS |
364 | auto_vec<gimple *> &v = ctx->null_check_map.get_or_insert (ptr); |
365 | gimple *g = maybe_get_dominating_check (v); | |
e28f2090 | 366 | if (!g) |
ab9a4330 JJ |
367 | { |
368 | /* For this PTR we don't have any UBSAN_NULL stmts recorded, so there's | |
369 | nothing to optimize yet. */ | |
370 | v.safe_push (stmt); | |
371 | return false; | |
372 | } | |
373 | ||
374 | /* We already have recorded a UBSAN_NULL check for this pointer. Perhaps we | |
375 | can drop this one. But only if this check doesn't specify stricter | |
376 | alignment. */ | |
ab9a4330 | 377 | |
e28f2090 YG |
378 | tree align = gimple_call_arg (g, 2); |
379 | int kind = tree_to_shwi (gimple_call_arg (g, 1)); | |
380 | /* If this is a NULL pointer check where we had segv anyway, we can | |
381 | remove it. */ | |
382 | if (integer_zerop (align) | |
383 | && (kind == UBSAN_LOAD_OF | |
384 | || kind == UBSAN_STORE_OF | |
385 | || kind == UBSAN_MEMBER_ACCESS)) | |
386 | remove = true; | |
387 | /* Otherwise remove the check in non-recovering mode, or if the | |
388 | stmts have same location. */ | |
389 | else if (integer_zerop (align)) | |
390 | remove = (flag_sanitize_recover & SANITIZE_NULL) == 0 | |
391 | || flag_sanitize_undefined_trap_on_error | |
392 | || gimple_location (g) == gimple_location (stmt); | |
393 | else if (tree_int_cst_le (cur_align, align)) | |
394 | remove = (flag_sanitize_recover & SANITIZE_ALIGNMENT) == 0 | |
395 | || flag_sanitize_undefined_trap_on_error | |
396 | || gimple_location (g) == gimple_location (stmt); | |
397 | ||
398 | if (!remove && gimple_bb (g) == gimple_bb (stmt) | |
399 | && tree_int_cst_compare (cur_align, align) == 0) | |
400 | v.pop (); | |
ab9a4330 JJ |
401 | |
402 | if (!remove) | |
403 | v.safe_push (stmt); | |
404 | return remove; | |
405 | } | |
406 | ||
513d5564 ML |
407 | /* Return true when pointer PTR for a given CUR_OFFSET is already sanitized |
408 | in a given sanitization context CTX. */ | |
409 | ||
410 | static bool | |
411 | has_dominating_ubsan_ptr_check (sanopt_ctx *ctx, tree ptr, | |
412 | offset_int &cur_offset) | |
413 | { | |
414 | bool pos_p = !wi::neg_p (cur_offset); | |
415 | sanopt_tree_couple couple; | |
416 | couple.ptr = ptr; | |
417 | couple.pos_p = pos_p; | |
418 | ||
419 | auto_vec<gimple *> &v = ctx->ptr_check_map.get_or_insert (couple); | |
420 | gimple *g = maybe_get_dominating_check (v); | |
421 | if (!g) | |
422 | return false; | |
423 | ||
424 | /* We already have recorded a UBSAN_PTR check for this pointer. Perhaps we | |
425 | can drop this one. But only if this check doesn't specify larger offset. | |
426 | */ | |
427 | tree offset = gimple_call_arg (g, 1); | |
428 | gcc_assert (TREE_CODE (offset) == INTEGER_CST); | |
429 | offset_int ooffset = wi::sext (wi::to_offset (offset), POINTER_SIZE); | |
430 | ||
431 | if (pos_p) | |
432 | { | |
433 | if (wi::les_p (cur_offset, ooffset)) | |
434 | return true; | |
435 | } | |
436 | else if (!pos_p && wi::les_p (ooffset, cur_offset)) | |
437 | return true; | |
438 | ||
439 | return false; | |
440 | } | |
441 | ||
442 | /* Record UBSAN_PTR check of given context CTX. Register pointer PTR on | |
443 | a given OFFSET that it's handled by GIMPLE STMT. */ | |
444 | ||
445 | static void | |
446 | record_ubsan_ptr_check_stmt (sanopt_ctx *ctx, gimple *stmt, tree ptr, | |
447 | const offset_int &offset) | |
448 | { | |
449 | sanopt_tree_couple couple; | |
450 | couple.ptr = ptr; | |
451 | couple.pos_p = !wi::neg_p (offset); | |
452 | ||
453 | auto_vec<gimple *> &v = ctx->ptr_check_map.get_or_insert (couple); | |
454 | v.safe_push (stmt); | |
455 | } | |
456 | ||
457 | /* Optimize away redundant UBSAN_PTR calls. */ | |
458 | ||
459 | static bool | |
460 | maybe_optimize_ubsan_ptr_ifn (sanopt_ctx *ctx, gimple *stmt) | |
461 | { | |
462 | HOST_WIDE_INT bitsize, bitpos; | |
463 | machine_mode mode; | |
464 | int volatilep = 0, reversep, unsignedp = 0; | |
465 | tree offset; | |
466 | ||
467 | gcc_assert (gimple_call_num_args (stmt) == 2); | |
468 | tree ptr = gimple_call_arg (stmt, 0); | |
469 | tree off = gimple_call_arg (stmt, 1); | |
470 | ||
471 | if (TREE_CODE (off) != INTEGER_CST) | |
472 | return false; | |
473 | ||
474 | if (integer_zerop (off)) | |
475 | return true; | |
476 | ||
477 | offset_int cur_offset = wi::sext (wi::to_offset (off), POINTER_SIZE); | |
478 | if (has_dominating_ubsan_ptr_check (ctx, ptr, cur_offset)) | |
479 | return true; | |
480 | ||
481 | tree base = ptr; | |
482 | if (TREE_CODE (base) == ADDR_EXPR) | |
483 | { | |
484 | base = TREE_OPERAND (base, 0); | |
485 | ||
486 | base = get_inner_reference (base, &bitsize, &bitpos, &offset, &mode, | |
487 | &unsignedp, &reversep, &volatilep); | |
488 | if (offset == NULL_TREE && DECL_P (base)) | |
489 | { | |
490 | gcc_assert (!DECL_REGISTER (base)); | |
491 | offset_int expr_offset = bitpos / BITS_PER_UNIT; | |
492 | offset_int total_offset = expr_offset + cur_offset; | |
493 | if (total_offset != wi::sext (total_offset, POINTER_SIZE)) | |
494 | { | |
495 | record_ubsan_ptr_check_stmt (ctx, stmt, ptr, cur_offset); | |
496 | return false; | |
497 | } | |
498 | ||
499 | /* If BASE is a fixed size automatic variable or | |
500 | global variable defined in the current TU, we don't have | |
501 | to instrument anything if offset is within address | |
502 | of the variable. */ | |
503 | if ((VAR_P (base) | |
504 | || TREE_CODE (base) == PARM_DECL | |
505 | || TREE_CODE (base) == RESULT_DECL) | |
506 | && DECL_SIZE_UNIT (base) | |
507 | && TREE_CODE (DECL_SIZE_UNIT (base)) == INTEGER_CST | |
508 | && (!is_global_var (base) || decl_binds_to_current_def_p (base))) | |
509 | { | |
510 | offset_int base_size = wi::to_offset (DECL_SIZE_UNIT (base)); | |
511 | if (bitpos >= 0 | |
512 | && wi::les_p (total_offset, base_size)) | |
513 | { | |
514 | if (!wi::neg_p (total_offset) | |
515 | && wi::les_p (total_offset, base_size)) | |
516 | return true; | |
517 | } | |
518 | } | |
519 | ||
520 | /* Following expression: UBSAN_PTR (&MEM_REF[ptr + x], y) can be | |
521 | handled as follows: | |
522 | ||
523 | 1) sign (x) == sign (y), then check for dominating check of (x + y) | |
524 | 2) sign (x) != sign (y), then first check if we have a dominating | |
525 | check for ptr + x. If so, then we have 2 situations: | |
526 | a) sign (x) == sign (x + y), here we are done, example: | |
527 | UBSAN_PTR (&MEM_REF[ptr + 100], -50) | |
528 | b) check for dominating check of ptr + x + y. | |
529 | */ | |
530 | ||
531 | bool sign_cur_offset = !wi::neg_p (cur_offset); | |
532 | bool sign_expr_offset = bitpos >= 0; | |
533 | ||
534 | tree base_addr | |
535 | = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (base)), base); | |
536 | ||
537 | bool add = false; | |
538 | if (sign_cur_offset == sign_expr_offset) | |
539 | { | |
540 | if (has_dominating_ubsan_ptr_check (ctx, base_addr, total_offset)) | |
541 | return true; | |
542 | else | |
543 | add = true; | |
544 | } | |
545 | else | |
546 | { | |
547 | if (!has_dominating_ubsan_ptr_check (ctx, base_addr, expr_offset)) | |
548 | ; /* Don't record base_addr + expr_offset, it's not a guarding | |
549 | check. */ | |
550 | else | |
551 | { | |
552 | bool sign_total_offset = !wi::neg_p (total_offset); | |
553 | if (sign_expr_offset == sign_total_offset) | |
554 | return true; | |
555 | else | |
556 | { | |
557 | if (has_dominating_ubsan_ptr_check (ctx, base_addr, | |
558 | total_offset)) | |
559 | return true; | |
560 | else | |
561 | add = true; | |
562 | } | |
563 | } | |
564 | } | |
565 | ||
566 | /* Record a new dominating check for base_addr + total_offset. */ | |
567 | if (add && !operand_equal_p (base, base_addr, 0)) | |
568 | record_ubsan_ptr_check_stmt (ctx, stmt, base_addr, | |
569 | total_offset); | |
570 | } | |
571 | } | |
572 | ||
573 | /* For this PTR we don't have any UBSAN_PTR stmts recorded, so there's | |
574 | nothing to optimize yet. */ | |
575 | record_ubsan_ptr_check_stmt (ctx, stmt, ptr, cur_offset); | |
576 | ||
577 | return false; | |
578 | } | |
579 | ||
35228ac7 JJ |
580 | /* Optimize away redundant UBSAN_VPTR calls. The second argument |
581 | is the value loaded from the virtual table, so rely on FRE to find out | |
582 | when we can actually optimize. */ | |
583 | ||
584 | static bool | |
355fe088 | 585 | maybe_optimize_ubsan_vptr_ifn (struct sanopt_ctx *ctx, gimple *stmt) |
35228ac7 JJ |
586 | { |
587 | gcc_assert (gimple_call_num_args (stmt) == 5); | |
588 | sanopt_tree_triplet triplet; | |
589 | triplet.t1 = gimple_call_arg (stmt, 0); | |
590 | triplet.t2 = gimple_call_arg (stmt, 1); | |
591 | triplet.t3 = gimple_call_arg (stmt, 3); | |
592 | ||
355fe088 TS |
593 | auto_vec<gimple *> &v = ctx->vptr_check_map.get_or_insert (triplet); |
594 | gimple *g = maybe_get_dominating_check (v); | |
35228ac7 JJ |
595 | if (!g) |
596 | { | |
597 | /* For this PTR we don't have any UBSAN_VPTR stmts recorded, so there's | |
598 | nothing to optimize yet. */ | |
599 | v.safe_push (stmt); | |
600 | return false; | |
601 | } | |
602 | ||
603 | return true; | |
604 | } | |
605 | ||
e28f2090 YG |
606 | /* Returns TRUE if ASan check of length LEN in block BB can be removed |
607 | if preceded by checks in V. */ | |
ab9a4330 JJ |
608 | |
609 | static bool | |
355fe088 | 610 | can_remove_asan_check (auto_vec<gimple *> &v, tree len, basic_block bb) |
ab9a4330 | 611 | { |
ab9a4330 | 612 | unsigned int i; |
355fe088 TS |
613 | gimple *g; |
614 | gimple *to_pop = NULL; | |
ab9a4330 JJ |
615 | bool remove = false; |
616 | basic_block last_bb = bb; | |
617 | bool cleanup = false; | |
618 | ||
619 | FOR_EACH_VEC_ELT_REVERSE (v, i, g) | |
620 | { | |
621 | basic_block gbb = gimple_bb (g); | |
622 | sanopt_info *si = (sanopt_info *) gbb->aux; | |
623 | if (gimple_uid (g) < si->freeing_call_events) | |
624 | { | |
625 | /* If there is a potentially freeing call after g in gbb, we should | |
626 | remove it from the vector, can't use in optimization. */ | |
627 | cleanup = true; | |
628 | continue; | |
629 | } | |
630 | ||
ab9a4330 | 631 | tree glen = gimple_call_arg (g, 2); |
e28f2090 YG |
632 | gcc_assert (TREE_CODE (glen) == INTEGER_CST); |
633 | ||
ab9a4330 JJ |
634 | /* If we've checked only smaller length than we want to check now, |
635 | we can't remove the current stmt. If g is in the same basic block, | |
636 | we want to remove it though, as the current stmt is better. */ | |
637 | if (tree_int_cst_lt (glen, len)) | |
638 | { | |
639 | if (gbb == bb) | |
640 | { | |
641 | to_pop = g; | |
642 | cleanup = true; | |
643 | } | |
644 | continue; | |
645 | } | |
646 | ||
647 | while (last_bb != gbb) | |
648 | { | |
649 | /* Paths from last_bb to bb have been checked before. | |
650 | gbb is necessarily a dominator of last_bb, but not necessarily | |
651 | immediate dominator. */ | |
652 | if (((sanopt_info *) last_bb->aux)->freeing_call_events) | |
653 | break; | |
654 | ||
655 | basic_block imm = get_immediate_dominator (CDI_DOMINATORS, last_bb); | |
656 | gcc_assert (imm); | |
657 | if (imm_dom_path_with_freeing_call (last_bb, imm)) | |
658 | break; | |
659 | ||
660 | last_bb = imm; | |
661 | } | |
662 | if (last_bb == gbb) | |
663 | remove = true; | |
664 | break; | |
665 | } | |
666 | ||
667 | if (cleanup) | |
668 | { | |
669 | unsigned int j = 0, l = v.length (); | |
670 | for (i = 0; i < l; i++) | |
671 | if (v[i] != to_pop | |
672 | && (gimple_uid (v[i]) | |
673 | == ((sanopt_info *) | |
674 | gimple_bb (v[i])->aux)->freeing_call_events)) | |
675 | { | |
676 | if (i != j) | |
677 | v[j] = v[i]; | |
678 | j++; | |
679 | } | |
680 | v.truncate (j); | |
681 | } | |
682 | ||
e28f2090 YG |
683 | return remove; |
684 | } | |
685 | ||
686 | /* Optimize away redundant ASAN_CHECK calls. */ | |
687 | ||
688 | static bool | |
355fe088 | 689 | maybe_optimize_asan_check_ifn (struct sanopt_ctx *ctx, gimple *stmt) |
e28f2090 YG |
690 | { |
691 | gcc_assert (gimple_call_num_args (stmt) == 4); | |
692 | tree ptr = gimple_call_arg (stmt, 1); | |
693 | tree len = gimple_call_arg (stmt, 2); | |
694 | basic_block bb = gimple_bb (stmt); | |
695 | sanopt_info *info = (sanopt_info *) bb->aux; | |
696 | ||
697 | if (TREE_CODE (len) != INTEGER_CST) | |
698 | return false; | |
699 | if (integer_zerop (len)) | |
700 | return false; | |
701 | ||
702 | gimple_set_uid (stmt, info->freeing_call_events); | |
703 | ||
355fe088 | 704 | auto_vec<gimple *> *ptr_checks = &ctx->asan_check_map.get_or_insert (ptr); |
e28f2090 YG |
705 | |
706 | tree base_addr = maybe_get_single_definition (ptr); | |
355fe088 | 707 | auto_vec<gimple *> *base_checks = NULL; |
e28f2090 YG |
708 | if (base_addr) |
709 | { | |
710 | base_checks = &ctx->asan_check_map.get_or_insert (base_addr); | |
711 | /* Original pointer might have been invalidated. */ | |
712 | ptr_checks = ctx->asan_check_map.get (ptr); | |
713 | } | |
714 | ||
355fe088 TS |
715 | gimple *g = maybe_get_dominating_check (*ptr_checks); |
716 | gimple *g2 = NULL; | |
e28f2090 | 717 | |
06dd2ace | 718 | if (base_checks) |
e28f2090 | 719 | /* Try with base address as well. */ |
06dd2ace | 720 | g2 = maybe_get_dominating_check (*base_checks); |
e28f2090 | 721 | |
06dd2ace | 722 | if (g == NULL && g2 == NULL) |
e28f2090 YG |
723 | { |
724 | /* For this PTR we don't have any ASAN_CHECK stmts recorded, so there's | |
725 | nothing to optimize yet. */ | |
726 | ptr_checks->safe_push (stmt); | |
727 | if (base_checks) | |
728 | base_checks->safe_push (stmt); | |
729 | return false; | |
730 | } | |
731 | ||
732 | bool remove = false; | |
733 | ||
734 | if (ptr_checks) | |
735 | remove = can_remove_asan_check (*ptr_checks, len, bb); | |
736 | ||
737 | if (!remove && base_checks) | |
738 | /* Try with base address as well. */ | |
739 | remove = can_remove_asan_check (*base_checks, len, bb); | |
740 | ||
ab9a4330 | 741 | if (!remove) |
e28f2090 YG |
742 | { |
743 | ptr_checks->safe_push (stmt); | |
744 | if (base_checks) | |
745 | base_checks->safe_push (stmt); | |
746 | } | |
747 | ||
ab9a4330 JJ |
748 | return remove; |
749 | } | |
750 | ||
751 | /* Try to optimize away redundant UBSAN_NULL and ASAN_CHECK calls. | |
752 | ||
06cefae9 | 753 | We walk blocks in the CFG via a depth first search of the dominator |
ab9a4330 JJ |
754 | tree; we push unique UBSAN_NULL or ASAN_CHECK statements into a vector |
755 | in the NULL_CHECK_MAP or ASAN_CHECK_MAP hash maps as we enter the | |
756 | blocks. When leaving a block, we mark the block as visited; then | |
757 | when checking the statements in the vector, we ignore statements that | |
758 | are coming from already visited blocks, because these cannot dominate | |
759 | anything anymore. CTX is a sanopt context. */ | |
06cefae9 MP |
760 | |
761 | static void | |
762 | sanopt_optimize_walker (basic_block bb, struct sanopt_ctx *ctx) | |
763 | { | |
764 | basic_block son; | |
765 | gimple_stmt_iterator gsi; | |
ab9a4330 | 766 | sanopt_info *info = (sanopt_info *) bb->aux; |
e28f2090 | 767 | bool asan_check_optimize = (flag_sanitize & SANITIZE_ADDRESS) != 0; |
06cefae9 MP |
768 | |
769 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);) | |
770 | { | |
355fe088 | 771 | gimple *stmt = gsi_stmt (gsi); |
06cefae9 MP |
772 | bool remove = false; |
773 | ||
ab9a4330 JJ |
774 | if (!is_gimple_call (stmt)) |
775 | { | |
776 | /* Handle asm volatile or asm with "memory" clobber | |
777 | the same as potentionally freeing call. */ | |
538dd0b7 DM |
778 | gasm *asm_stmt = dyn_cast <gasm *> (stmt); |
779 | if (asm_stmt | |
ab9a4330 | 780 | && asan_check_optimize |
538dd0b7 DM |
781 | && (gimple_asm_clobbers_memory_p (asm_stmt) |
782 | || gimple_asm_volatile_p (asm_stmt))) | |
ab9a4330 JJ |
783 | info->freeing_call_events++; |
784 | gsi_next (&gsi); | |
785 | continue; | |
786 | } | |
787 | ||
788 | if (asan_check_optimize && !nonfreeing_call_p (stmt)) | |
789 | info->freeing_call_events++; | |
790 | ||
94087e88 JJ |
791 | /* If __asan_before_dynamic_init ("module"); is followed by |
792 | __asan_after_dynamic_init (); without intervening memory loads/stores, | |
793 | there is nothing to guard, so optimize both away. */ | |
794 | if (asan_check_optimize | |
795 | && gimple_call_builtin_p (stmt, BUILT_IN_ASAN_BEFORE_DYNAMIC_INIT)) | |
796 | { | |
797 | use_operand_p use; | |
798 | gimple *use_stmt; | |
799 | if (single_imm_use (gimple_vdef (stmt), &use, &use_stmt)) | |
800 | { | |
801 | if (is_gimple_call (use_stmt) | |
802 | && gimple_call_builtin_p (use_stmt, | |
803 | BUILT_IN_ASAN_AFTER_DYNAMIC_INIT)) | |
804 | { | |
805 | unlink_stmt_vdef (use_stmt); | |
806 | gimple_stmt_iterator gsi2 = gsi_for_stmt (use_stmt); | |
807 | gsi_remove (&gsi2, true); | |
808 | remove = true; | |
809 | } | |
810 | } | |
811 | } | |
812 | ||
ab9a4330 | 813 | if (gimple_call_internal_p (stmt)) |
06cefae9 MP |
814 | switch (gimple_call_internal_fn (stmt)) |
815 | { | |
816 | case IFN_UBSAN_NULL: | |
ab9a4330 JJ |
817 | remove = maybe_optimize_ubsan_null_ifn (ctx, stmt); |
818 | break; | |
35228ac7 JJ |
819 | case IFN_UBSAN_VPTR: |
820 | remove = maybe_optimize_ubsan_vptr_ifn (ctx, stmt); | |
821 | break; | |
513d5564 ML |
822 | case IFN_UBSAN_PTR: |
823 | remove = maybe_optimize_ubsan_ptr_ifn (ctx, stmt); | |
824 | break; | |
06cefae9 | 825 | case IFN_ASAN_CHECK: |
ab9a4330 JJ |
826 | if (asan_check_optimize) |
827 | remove = maybe_optimize_asan_check_ifn (ctx, stmt); | |
828 | if (!remove) | |
829 | ctx->asan_num_accesses++; | |
06cefae9 | 830 | break; |
2f75d6eb ML |
831 | case IFN_ASAN_MARK: |
832 | ctx->contains_asan_mark = true; | |
833 | break; | |
06cefae9 MP |
834 | default: |
835 | break; | |
836 | } | |
837 | ||
ab9a4330 JJ |
838 | if (remove) |
839 | { | |
840 | /* Drop this check. */ | |
841 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
842 | { | |
513d5564 | 843 | fprintf (dump_file, "Optimizing out: "); |
ab9a4330 | 844 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
ab9a4330 JJ |
845 | } |
846 | unlink_stmt_vdef (stmt); | |
847 | gsi_remove (&gsi, true); | |
848 | } | |
849 | else | |
513d5564 ML |
850 | { |
851 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
852 | { | |
853 | fprintf (dump_file, "Leaving: "); | |
854 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); | |
855 | } | |
856 | ||
857 | gsi_next (&gsi); | |
858 | } | |
06cefae9 MP |
859 | } |
860 | ||
ab9a4330 JJ |
861 | if (asan_check_optimize) |
862 | { | |
863 | info->has_freeing_call_p = info->freeing_call_events != 0; | |
864 | info->has_freeing_call_computed_p = true; | |
865 | } | |
866 | ||
06cefae9 MP |
867 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
868 | son; | |
869 | son = next_dom_son (CDI_DOMINATORS, son)) | |
870 | sanopt_optimize_walker (son, ctx); | |
871 | ||
872 | /* We're leaving this BB, so mark it to that effect. */ | |
06cefae9 MP |
873 | info->visited_p = true; |
874 | } | |
875 | ||
876 | /* Try to remove redundant sanitizer checks in function FUN. */ | |
877 | ||
878 | static int | |
2f75d6eb | 879 | sanopt_optimize (function *fun, bool *contains_asan_mark) |
06cefae9 MP |
880 | { |
881 | struct sanopt_ctx ctx; | |
882 | ctx.asan_num_accesses = 0; | |
2f75d6eb | 883 | ctx.contains_asan_mark = false; |
06cefae9 MP |
884 | |
885 | /* Set up block info for each basic block. */ | |
886 | alloc_aux_for_blocks (sizeof (sanopt_info)); | |
887 | ||
888 | /* We're going to do a dominator walk, so ensure that we have | |
889 | dominance information. */ | |
890 | calculate_dominance_info (CDI_DOMINATORS); | |
891 | ||
892 | /* Recursively walk the dominator tree optimizing away | |
893 | redundant checks. */ | |
894 | sanopt_optimize_walker (ENTRY_BLOCK_PTR_FOR_FN (fun), &ctx); | |
895 | ||
896 | free_aux_for_blocks (); | |
897 | ||
2f75d6eb | 898 | *contains_asan_mark = ctx.contains_asan_mark; |
06cefae9 MP |
899 | return ctx.asan_num_accesses; |
900 | } | |
901 | ||
902 | /* Perform optimization of sanitize functions. */ | |
903 | ||
17795822 TS |
904 | namespace { |
905 | ||
906 | const pass_data pass_data_sanopt = | |
06cefae9 MP |
907 | { |
908 | GIMPLE_PASS, /* type */ | |
909 | "sanopt", /* name */ | |
910 | OPTGROUP_NONE, /* optinfo_flags */ | |
911 | TV_NONE, /* tv_id */ | |
912 | ( PROP_ssa | PROP_cfg | PROP_gimple_leh ), /* properties_required */ | |
913 | 0, /* properties_provided */ | |
914 | 0, /* properties_destroyed */ | |
915 | 0, /* todo_flags_start */ | |
916 | TODO_update_ssa, /* todo_flags_finish */ | |
917 | }; | |
918 | ||
17795822 | 919 | class pass_sanopt : public gimple_opt_pass |
06cefae9 MP |
920 | { |
921 | public: | |
922 | pass_sanopt (gcc::context *ctxt) | |
923 | : gimple_opt_pass (pass_data_sanopt, ctxt) | |
924 | {} | |
925 | ||
926 | /* opt_pass methods: */ | |
927 | virtual bool gate (function *) { return flag_sanitize; } | |
928 | virtual unsigned int execute (function *); | |
929 | ||
930 | }; // class pass_sanopt | |
931 | ||
2f75d6eb ML |
932 | /* Sanitize all ASAN_MARK unpoison calls that are not reachable by a BB |
933 | that contains an ASAN_MARK poison. All these ASAN_MARK unpoison call | |
934 | can be removed as all variables are unpoisoned in a function prologue. */ | |
935 | ||
936 | static void | |
937 | sanitize_asan_mark_unpoison (void) | |
938 | { | |
939 | /* 1) Find all BBs that contain an ASAN_MARK poison call. */ | |
940 | auto_sbitmap with_poison (last_basic_block_for_fn (cfun) + 1); | |
941 | bitmap_clear (with_poison); | |
942 | basic_block bb; | |
943 | ||
944 | FOR_EACH_BB_FN (bb, cfun) | |
945 | { | |
946 | if (bitmap_bit_p (with_poison, bb->index)) | |
947 | continue; | |
948 | ||
949 | gimple_stmt_iterator gsi; | |
950 | for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi)) | |
951 | { | |
952 | gimple *stmt = gsi_stmt (gsi); | |
953 | if (asan_mark_p (stmt, ASAN_MARK_POISON)) | |
954 | { | |
955 | bitmap_set_bit (with_poison, bb->index); | |
956 | break; | |
957 | } | |
958 | } | |
959 | } | |
960 | ||
961 | auto_sbitmap poisoned (last_basic_block_for_fn (cfun) + 1); | |
962 | bitmap_clear (poisoned); | |
963 | auto_sbitmap worklist (last_basic_block_for_fn (cfun) + 1); | |
964 | bitmap_copy (worklist, with_poison); | |
965 | ||
966 | /* 2) Propagate the information to all reachable blocks. */ | |
967 | while (!bitmap_empty_p (worklist)) | |
968 | { | |
969 | unsigned i = bitmap_first_set_bit (worklist); | |
970 | bitmap_clear_bit (worklist, i); | |
971 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i); | |
972 | gcc_assert (bb); | |
973 | ||
974 | edge e; | |
975 | edge_iterator ei; | |
976 | FOR_EACH_EDGE (e, ei, bb->succs) | |
977 | if (!bitmap_bit_p (poisoned, e->dest->index)) | |
978 | { | |
979 | bitmap_set_bit (poisoned, e->dest->index); | |
980 | bitmap_set_bit (worklist, e->dest->index); | |
981 | } | |
982 | } | |
983 | ||
984 | /* 3) Iterate all BBs not included in POISONED BBs and remove unpoison | |
985 | ASAN_MARK preceding an ASAN_MARK poison (which can still happen). */ | |
986 | FOR_EACH_BB_FN (bb, cfun) | |
987 | { | |
988 | if (bitmap_bit_p (poisoned, bb->index)) | |
989 | continue; | |
990 | ||
991 | gimple_stmt_iterator gsi; | |
992 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);) | |
993 | { | |
2f75d6eb ML |
994 | gimple *stmt = gsi_stmt (gsi); |
995 | if (gimple_call_internal_p (stmt, IFN_ASAN_MARK)) | |
996 | { | |
997 | if (asan_mark_p (stmt, ASAN_MARK_POISON)) | |
998 | break; | |
999 | else | |
1000 | { | |
1001 | if (dump_file) | |
1002 | fprintf (dump_file, "Removing ASAN_MARK unpoison\n"); | |
1003 | unlink_stmt_vdef (stmt); | |
1004 | release_defs (stmt); | |
1005 | gsi_remove (&gsi, true); | |
8ccaace8 | 1006 | continue; |
2f75d6eb ML |
1007 | } |
1008 | } | |
1009 | ||
8ccaace8 | 1010 | gsi_next (&gsi); |
2f75d6eb ML |
1011 | } |
1012 | } | |
1013 | } | |
1014 | ||
1015 | /* Return true when STMT is either ASAN_CHECK call or a call of a function | |
1016 | that can contain an ASAN_CHECK. */ | |
1017 | ||
1018 | static bool | |
1019 | maybe_contains_asan_check (gimple *stmt) | |
1020 | { | |
1021 | if (is_gimple_call (stmt)) | |
1022 | { | |
1023 | if (gimple_call_internal_p (stmt, IFN_ASAN_MARK)) | |
1024 | return false; | |
1025 | else | |
1026 | return !(gimple_call_flags (stmt) & ECF_CONST); | |
1027 | } | |
1028 | else if (is_a<gasm *> (stmt)) | |
1029 | return true; | |
1030 | ||
1031 | return false; | |
1032 | } | |
1033 | ||
1034 | /* Sanitize all ASAN_MARK poison calls that are not followed by an ASAN_CHECK | |
1035 | call. These calls can be removed. */ | |
1036 | ||
1037 | static void | |
1038 | sanitize_asan_mark_poison (void) | |
1039 | { | |
1040 | /* 1) Find all BBs that possibly contain an ASAN_CHECK. */ | |
1041 | auto_sbitmap with_check (last_basic_block_for_fn (cfun) + 1); | |
1042 | bitmap_clear (with_check); | |
1043 | basic_block bb; | |
1044 | ||
1045 | FOR_EACH_BB_FN (bb, cfun) | |
1046 | { | |
1047 | gimple_stmt_iterator gsi; | |
1048 | for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi)) | |
1049 | { | |
1050 | gimple *stmt = gsi_stmt (gsi); | |
1051 | if (maybe_contains_asan_check (stmt)) | |
1052 | { | |
1053 | bitmap_set_bit (with_check, bb->index); | |
1054 | break; | |
1055 | } | |
1056 | } | |
1057 | } | |
1058 | ||
1059 | auto_sbitmap can_reach_check (last_basic_block_for_fn (cfun) + 1); | |
1060 | bitmap_clear (can_reach_check); | |
1061 | auto_sbitmap worklist (last_basic_block_for_fn (cfun) + 1); | |
1062 | bitmap_copy (worklist, with_check); | |
1063 | ||
1064 | /* 2) Propagate the information to all definitions blocks. */ | |
1065 | while (!bitmap_empty_p (worklist)) | |
1066 | { | |
1067 | unsigned i = bitmap_first_set_bit (worklist); | |
1068 | bitmap_clear_bit (worklist, i); | |
1069 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i); | |
1070 | gcc_assert (bb); | |
1071 | ||
1072 | edge e; | |
1073 | edge_iterator ei; | |
1074 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1075 | if (!bitmap_bit_p (can_reach_check, e->src->index)) | |
1076 | { | |
1077 | bitmap_set_bit (can_reach_check, e->src->index); | |
1078 | bitmap_set_bit (worklist, e->src->index); | |
1079 | } | |
1080 | } | |
1081 | ||
1082 | /* 3) Iterate all BBs not included in CAN_REACH_CHECK BBs and remove poison | |
1083 | ASAN_MARK not followed by a call to function having an ASAN_CHECK. */ | |
1084 | FOR_EACH_BB_FN (bb, cfun) | |
1085 | { | |
1086 | if (bitmap_bit_p (can_reach_check, bb->index)) | |
1087 | continue; | |
1088 | ||
1089 | gimple_stmt_iterator gsi; | |
1090 | for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi);) | |
1091 | { | |
2f75d6eb ML |
1092 | gimple *stmt = gsi_stmt (gsi); |
1093 | if (maybe_contains_asan_check (stmt)) | |
1094 | break; | |
1095 | else if (asan_mark_p (stmt, ASAN_MARK_POISON)) | |
1096 | { | |
1097 | if (dump_file) | |
1098 | fprintf (dump_file, "Removing ASAN_MARK poison\n"); | |
1099 | unlink_stmt_vdef (stmt); | |
1100 | release_defs (stmt); | |
8ccaace8 JJ |
1101 | gimple_stmt_iterator gsi2 = gsi; |
1102 | gsi_prev (&gsi); | |
1103 | gsi_remove (&gsi2, true); | |
1104 | continue; | |
2f75d6eb ML |
1105 | } |
1106 | ||
8ccaace8 | 1107 | gsi_prev (&gsi); |
2f75d6eb ML |
1108 | } |
1109 | } | |
1110 | } | |
1111 | ||
da402967 ML |
1112 | /* Rewrite all usages of tree OP which is a PARM_DECL with a VAR_DECL |
1113 | that is it's DECL_VALUE_EXPR. */ | |
1114 | ||
1115 | static tree | |
1116 | rewrite_usage_of_param (tree *op, int *walk_subtrees, void *) | |
1117 | { | |
1118 | if (TREE_CODE (*op) == PARM_DECL && DECL_HAS_VALUE_EXPR_P (*op)) | |
1119 | { | |
1120 | *op = DECL_VALUE_EXPR (*op); | |
1121 | *walk_subtrees = 0; | |
1122 | } | |
1123 | ||
1124 | return NULL; | |
1125 | } | |
1126 | ||
1127 | /* For a given function FUN, rewrite all addressable parameters so that | |
1128 | a new automatic variable is introduced. Right after function entry | |
1129 | a parameter is assigned to the variable. */ | |
1130 | ||
1131 | static void | |
1132 | sanitize_rewrite_addressable_params (function *fun) | |
1133 | { | |
1134 | gimple *g; | |
1135 | gimple_seq stmts = NULL; | |
1136 | bool has_any_addressable_param = false; | |
1137 | auto_vec<tree> clear_value_expr_list; | |
1138 | ||
1139 | for (tree arg = DECL_ARGUMENTS (current_function_decl); | |
1140 | arg; arg = DECL_CHAIN (arg)) | |
1141 | { | |
70affe6a | 1142 | tree type = TREE_TYPE (arg); |
ed89e76a | 1143 | if (TREE_ADDRESSABLE (arg) && !TREE_ADDRESSABLE (type) |
70affe6a | 1144 | && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST) |
da402967 ML |
1145 | { |
1146 | TREE_ADDRESSABLE (arg) = 0; | |
1147 | /* The parameter is no longer addressable. */ | |
da402967 ML |
1148 | has_any_addressable_param = true; |
1149 | ||
1150 | /* Create a new automatic variable. */ | |
1151 | tree var = build_decl (DECL_SOURCE_LOCATION (arg), | |
1152 | VAR_DECL, DECL_NAME (arg), type); | |
1153 | TREE_ADDRESSABLE (var) = 1; | |
7c819e8a | 1154 | DECL_IGNORED_P (var) = 1; |
da402967 ML |
1155 | |
1156 | gimple_add_tmp_var (var); | |
1157 | ||
1158 | if (dump_file) | |
1159 | fprintf (dump_file, | |
1160 | "Rewriting parameter whose address is taken: %s\n", | |
1161 | IDENTIFIER_POINTER (DECL_NAME (arg))); | |
1162 | ||
1163 | gcc_assert (!DECL_HAS_VALUE_EXPR_P (arg)); | |
da402967 ML |
1164 | |
1165 | SET_DECL_PT_UID (var, DECL_PT_UID (arg)); | |
1166 | ||
1167 | /* Assign value of parameter to newly created variable. */ | |
1168 | if ((TREE_CODE (type) == COMPLEX_TYPE | |
1169 | || TREE_CODE (type) == VECTOR_TYPE)) | |
1170 | { | |
1171 | /* We need to create a SSA name that will be used for the | |
1172 | assignment. */ | |
1173 | DECL_GIMPLE_REG_P (arg) = 1; | |
1174 | tree tmp = get_or_create_ssa_default_def (cfun, arg); | |
1175 | g = gimple_build_assign (var, tmp); | |
1176 | gimple_set_location (g, DECL_SOURCE_LOCATION (arg)); | |
1177 | gimple_seq_add_stmt (&stmts, g); | |
1178 | } | |
1179 | else | |
1180 | { | |
1181 | g = gimple_build_assign (var, arg); | |
1182 | gimple_set_location (g, DECL_SOURCE_LOCATION (arg)); | |
1183 | gimple_seq_add_stmt (&stmts, g); | |
1184 | } | |
1185 | ||
1186 | if (target_for_debug_bind (arg)) | |
1187 | { | |
1188 | g = gimple_build_debug_bind (arg, var, NULL); | |
1189 | gimple_seq_add_stmt (&stmts, g); | |
1190 | clear_value_expr_list.safe_push (arg); | |
1191 | } | |
6d7649f8 ML |
1192 | |
1193 | DECL_HAS_VALUE_EXPR_P (arg) = 1; | |
1194 | SET_DECL_VALUE_EXPR (arg, var); | |
da402967 ML |
1195 | } |
1196 | } | |
1197 | ||
1198 | if (!has_any_addressable_param) | |
1199 | return; | |
1200 | ||
1201 | /* Replace all usages of PARM_DECLs with the newly | |
1202 | created variable VAR. */ | |
1203 | basic_block bb; | |
1204 | FOR_EACH_BB_FN (bb, fun) | |
1205 | { | |
1206 | gimple_stmt_iterator gsi; | |
1207 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1208 | { | |
1209 | gimple *stmt = gsi_stmt (gsi); | |
1210 | gimple_stmt_iterator it = gsi_for_stmt (stmt); | |
1211 | walk_gimple_stmt (&it, NULL, rewrite_usage_of_param, NULL); | |
1212 | } | |
1213 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1214 | { | |
1215 | gphi *phi = dyn_cast<gphi *> (gsi_stmt (gsi)); | |
1216 | for (unsigned i = 0; i < gimple_phi_num_args (phi); ++i) | |
1217 | { | |
1218 | hash_set<tree> visited_nodes; | |
1219 | walk_tree (gimple_phi_arg_def_ptr (phi, i), | |
1220 | rewrite_usage_of_param, NULL, &visited_nodes); | |
1221 | } | |
1222 | } | |
1223 | } | |
1224 | ||
1225 | /* Unset value expr for parameters for which we created debug bind | |
1226 | expressions. */ | |
1227 | unsigned i; | |
1228 | tree arg; | |
1229 | FOR_EACH_VEC_ELT (clear_value_expr_list, i, arg) | |
1230 | { | |
1231 | DECL_HAS_VALUE_EXPR_P (arg) = 0; | |
1232 | SET_DECL_VALUE_EXPR (arg, NULL_TREE); | |
1233 | } | |
1234 | ||
1235 | /* Insert default assignments at the beginning of a function. */ | |
1236 | basic_block entry_bb = ENTRY_BLOCK_PTR_FOR_FN (fun); | |
1237 | entry_bb = split_edge (single_succ_edge (entry_bb)); | |
1238 | ||
1239 | gimple_stmt_iterator gsi = gsi_start_bb (entry_bb); | |
1240 | gsi_insert_seq_before (&gsi, stmts, GSI_NEW_STMT); | |
1241 | } | |
1242 | ||
06cefae9 MP |
1243 | unsigned int |
1244 | pass_sanopt::execute (function *fun) | |
1245 | { | |
1246 | basic_block bb; | |
1247 | int asan_num_accesses = 0; | |
2f75d6eb | 1248 | bool contains_asan_mark = false; |
06cefae9 MP |
1249 | |
1250 | /* Try to remove redundant checks. */ | |
1251 | if (optimize | |
ab9a4330 | 1252 | && (flag_sanitize |
35228ac7 | 1253 | & (SANITIZE_NULL | SANITIZE_ALIGNMENT |
513d5564 | 1254 | | SANITIZE_ADDRESS | SANITIZE_VPTR | SANITIZE_POINTER_OVERFLOW))) |
2f75d6eb | 1255 | asan_num_accesses = sanopt_optimize (fun, &contains_asan_mark); |
06cefae9 MP |
1256 | else if (flag_sanitize & SANITIZE_ADDRESS) |
1257 | { | |
1258 | gimple_stmt_iterator gsi; | |
1259 | FOR_EACH_BB_FN (bb, fun) | |
1260 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1261 | { | |
355fe088 | 1262 | gimple *stmt = gsi_stmt (gsi); |
8e4284d0 | 1263 | if (gimple_call_internal_p (stmt, IFN_ASAN_CHECK)) |
06cefae9 | 1264 | ++asan_num_accesses; |
2f75d6eb ML |
1265 | else if (gimple_call_internal_p (stmt, IFN_ASAN_MARK)) |
1266 | contains_asan_mark = true; | |
06cefae9 MP |
1267 | } |
1268 | } | |
1269 | ||
2f75d6eb ML |
1270 | if (contains_asan_mark) |
1271 | { | |
1272 | sanitize_asan_mark_unpoison (); | |
1273 | sanitize_asan_mark_poison (); | |
1274 | } | |
1275 | ||
da402967 ML |
1276 | if (asan_sanitize_stack_p ()) |
1277 | sanitize_rewrite_addressable_params (fun); | |
1278 | ||
06cefae9 MP |
1279 | bool use_calls = ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD < INT_MAX |
1280 | && asan_num_accesses >= ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD; | |
1281 | ||
c7775327 ML |
1282 | hash_map<tree, tree> shadow_vars_mapping; |
1283 | bool need_commit_edge_insert = false; | |
06cefae9 MP |
1284 | FOR_EACH_BB_FN (bb, fun) |
1285 | { | |
1286 | gimple_stmt_iterator gsi; | |
1287 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) | |
1288 | { | |
355fe088 | 1289 | gimple *stmt = gsi_stmt (gsi); |
06cefae9 MP |
1290 | bool no_next = false; |
1291 | ||
1292 | if (!is_gimple_call (stmt)) | |
1293 | { | |
1294 | gsi_next (&gsi); | |
1295 | continue; | |
1296 | } | |
1297 | ||
1298 | if (gimple_call_internal_p (stmt)) | |
1299 | { | |
1300 | enum internal_fn ifn = gimple_call_internal_fn (stmt); | |
1301 | switch (ifn) | |
1302 | { | |
1303 | case IFN_UBSAN_NULL: | |
1304 | no_next = ubsan_expand_null_ifn (&gsi); | |
1305 | break; | |
1306 | case IFN_UBSAN_BOUNDS: | |
1307 | no_next = ubsan_expand_bounds_ifn (&gsi); | |
1308 | break; | |
1309 | case IFN_UBSAN_OBJECT_SIZE: | |
1310 | no_next = ubsan_expand_objsize_ifn (&gsi); | |
1311 | break; | |
c9b39a49 JJ |
1312 | case IFN_UBSAN_PTR: |
1313 | no_next = ubsan_expand_ptr_ifn (&gsi); | |
1314 | break; | |
35228ac7 JJ |
1315 | case IFN_UBSAN_VPTR: |
1316 | no_next = ubsan_expand_vptr_ifn (&gsi); | |
1317 | break; | |
06cefae9 MP |
1318 | case IFN_ASAN_CHECK: |
1319 | no_next = asan_expand_check_ifn (&gsi, use_calls); | |
1320 | break; | |
6dc4a604 ML |
1321 | case IFN_ASAN_MARK: |
1322 | no_next = asan_expand_mark_ifn (&gsi); | |
1323 | break; | |
c7775327 ML |
1324 | case IFN_ASAN_POISON: |
1325 | no_next = asan_expand_poison_ifn (&gsi, | |
1326 | &need_commit_edge_insert, | |
1327 | shadow_vars_mapping); | |
1328 | break; | |
06cefae9 MP |
1329 | default: |
1330 | break; | |
1331 | } | |
1332 | } | |
4088b790 MP |
1333 | else if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) |
1334 | { | |
1335 | tree callee = gimple_call_fndecl (stmt); | |
1336 | switch (DECL_FUNCTION_CODE (callee)) | |
1337 | { | |
1338 | case BUILT_IN_UNREACHABLE: | |
45b2222a | 1339 | if (sanitize_flags_p (SANITIZE_UNREACHABLE)) |
4088b790 MP |
1340 | no_next = ubsan_instrument_unreachable (&gsi); |
1341 | break; | |
1342 | default: | |
1343 | break; | |
1344 | } | |
1345 | } | |
06cefae9 MP |
1346 | |
1347 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1348 | { | |
513d5564 | 1349 | fprintf (dump_file, "Expanded: "); |
06cefae9 | 1350 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
06cefae9 MP |
1351 | } |
1352 | ||
1353 | if (!no_next) | |
1354 | gsi_next (&gsi); | |
1355 | } | |
1356 | } | |
c7775327 ML |
1357 | |
1358 | if (need_commit_edge_insert) | |
1359 | gsi_commit_edge_inserts (); | |
1360 | ||
06cefae9 MP |
1361 | return 0; |
1362 | } | |
1363 | ||
17795822 TS |
1364 | } // anon namespace |
1365 | ||
06cefae9 MP |
1366 | gimple_opt_pass * |
1367 | make_pass_sanopt (gcc::context *ctxt) | |
1368 | { | |
1369 | return new pass_sanopt (ctxt); | |
1370 | } |