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34f97b94 | 1 | /* Predicate aware uninitialized variable warning. |
7adcbafe | 2 | Copyright (C) 2001-2022 Free Software Foundation, Inc. |
34f97b94 XDL |
3 | Contributed by Xinliang David Li <davidxl@google.com> |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3, or (at your option) | |
10 | any later version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License 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 | ||
72be80e4 | 21 | #define INCLUDE_STRING |
34f97b94 XDL |
22 | #include "config.h" |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
c7131fb2 | 25 | #include "backend.h" |
34f97b94 | 26 | #include "tree.h" |
c7131fb2 | 27 | #include "gimple.h" |
957060b5 | 28 | #include "tree-pass.h" |
c7131fb2 | 29 | #include "ssa.h" |
957060b5 AM |
30 | #include "gimple-pretty-print.h" |
31 | #include "diagnostic-core.h" | |
40e23961 | 32 | #include "fold-const.h" |
5be5c238 | 33 | #include "gimple-iterator.h" |
442b4905 | 34 | #include "tree-ssa.h" |
666e8e06 | 35 | #include "tree-cfg.h" |
11ef0b22 | 36 | #include "cfghooks.h" |
b825a228 MS |
37 | #include "attribs.h" |
38 | #include "builtins.h" | |
39 | #include "calls.h" | |
45f4e2b0 | 40 | #include "gimple-range.h" |
94c12ffa | 41 | #include "gimple-predicate-analysis.h" |
0f58ba4d RB |
42 | #include "domwalk.h" |
43 | #include "tree-ssa-sccvn.h" | |
c77fae1c | 44 | #include "cfganal.h" |
94c12ffa | 45 | |
34f97b94 | 46 | /* This implements the pass that does predicate aware warning on uses of |
ac0e4fde ML |
47 | possibly uninitialized variables. The pass first collects the set of |
48 | possibly uninitialized SSA names. For each such name, it walks through | |
49 | all its immediate uses. For each immediate use, it rebuilds the condition | |
50 | expression (the predicate) that guards the use. The predicate is then | |
34f97b94 XDL |
51 | examined to see if the variable is always defined under that same condition. |
52 | This is done either by pruning the unrealizable paths that lead to the | |
53 | default definitions or by checking if the predicate set that guards the | |
54 | defining paths is a superset of the use predicate. */ | |
55 | ||
34f97b94 XDL |
56 | /* Pointer set of potentially undefined ssa names, i.e., |
57 | ssa names that are defined by phi with operands that | |
58 | are not defined or potentially undefined. */ | |
4a8f98fa RB |
59 | static hash_set<tree> *possibly_undefined_names; |
60 | static hash_map<gphi *, uninit_analysis::func_t::phi_arg_set_t> *defined_args; | |
34f97b94 | 61 | |
34f97b94 | 62 | /* Returns the first bit position (starting from LSB) |
ac0e4fde | 63 | in mask that is non zero. Returns -1 if the mask is empty. */ |
34f97b94 XDL |
64 | static int |
65 | get_mask_first_set_bit (unsigned mask) | |
66 | { | |
67 | int pos = 0; | |
68 | if (mask == 0) | |
69 | return -1; | |
70 | ||
71 | while ((mask & (1 << pos)) == 0) | |
72 | pos++; | |
73 | ||
74 | return pos; | |
75 | } | |
76 | #define MASK_FIRST_SET_BIT(mask) get_mask_first_set_bit (mask) | |
77 | ||
34f97b94 | 78 | /* Return true if T, an SSA_NAME, has an undefined value. */ |
c152901f AM |
79 | static bool |
80 | has_undefined_value_p (tree t) | |
34f97b94 | 81 | { |
c152901f | 82 | return (ssa_undefined_value_p (t) |
5e48d8a0 ML |
83 | || (possibly_undefined_names |
84 | && possibly_undefined_names->contains (t))); | |
34f97b94 XDL |
85 | } |
86 | ||
e9e2bad7 MS |
87 | /* Return true if EXPR should suppress either uninitialized warning. */ |
88 | ||
89 | static inline bool | |
90 | get_no_uninit_warning (tree expr) | |
91 | { | |
92 | return warning_suppressed_p (expr, OPT_Wuninitialized); | |
93 | } | |
94 | ||
95 | /* Suppress both uninitialized warnings for EXPR. */ | |
96 | ||
97 | static inline void | |
98 | set_no_uninit_warning (tree expr) | |
99 | { | |
100 | suppress_warning (expr, OPT_Wuninitialized); | |
101 | } | |
102 | ||
103 | /* Like has_undefined_value_p, but don't return true if the no-warning | |
104 | bit is set on SSA_NAME_VAR for either uninit warning. */ | |
ba7e83f8 JJ |
105 | |
106 | static inline bool | |
ac0e4fde ML |
107 | uninit_undefined_value_p (tree t) |
108 | { | |
c152901f | 109 | if (!has_undefined_value_p (t)) |
ba7e83f8 | 110 | return false; |
e9e2bad7 MS |
111 | if (!SSA_NAME_VAR (t)) |
112 | return true; | |
113 | return !get_no_uninit_warning (SSA_NAME_VAR (t)); | |
ba7e83f8 JJ |
114 | } |
115 | ||
c152901f AM |
116 | /* Emit warnings for uninitialized variables. This is done in two passes. |
117 | ||
118 | The first pass notices real uses of SSA names with undefined values. | |
119 | Such uses are unconditionally uninitialized, and we can be certain that | |
120 | such a use is a mistake. This pass is run before most optimizations, | |
121 | so that we catch as many as we can. | |
122 | ||
123 | The second pass follows PHI nodes to find uses that are potentially | |
124 | uninitialized. In this case we can't necessarily prove that the use | |
125 | is really uninitialized. This pass is run after most optimizations, | |
126 | so that we thread as many jumps and possible, and delete as much dead | |
127 | code as possible, in order to reduce false positives. We also look | |
128 | again for plain uninitialized variables, since optimization may have | |
129 | changed conditionally uninitialized to unconditionally uninitialized. */ | |
130 | ||
4e84e381 MS |
131 | /* Emit warning OPT for variable VAR at the point in the program where |
132 | the SSA_NAME T is being used uninitialized. The warning text is in | |
133 | MSGID and STMT is the statement that does the uninitialized read. | |
134 | PHI_ARG_LOC is the location of the PHI argument if T and VAR are one, | |
135 | or UNKNOWN_LOCATION otherwise. */ | |
c152901f AM |
136 | |
137 | static void | |
6cb61e50 QZ |
138 | warn_uninit (opt_code opt, tree t, tree var, gimple *context, |
139 | location_t phi_arg_loc = UNKNOWN_LOCATION) | |
c152901f | 140 | { |
4e84e381 MS |
141 | /* Bail if the value isn't provably uninitialized. */ |
142 | if (!has_undefined_value_p (t)) | |
143 | return; | |
c152901f | 144 | |
e1ec47c4 TP |
145 | /* Ignore COMPLEX_EXPR as initializing only a part of a complex |
146 | turns in a COMPLEX_EXPR with the not initialized part being | |
147 | set to its previous (undefined) value. */ | |
148 | if (is_gimple_assign (context) | |
149 | && gimple_assign_rhs_code (context) == COMPLEX_EXPR) | |
150 | return; | |
a25e0b5e | 151 | |
152 | /* Ignore REALPART_EXPR or IMAGPART_EXPR if its operand is a call to | |
153 | .DEFERRED_INIT. This is for handling the following case correctly: | |
154 | ||
155 | 1 typedef _Complex float C; | |
156 | 2 C foo (int cond) | |
157 | 3 { | |
158 | 4 C f; | |
159 | 5 __imag__ f = 0; | |
160 | 6 if (cond) | |
161 | 7 { | |
162 | 8 __real__ f = 1; | |
163 | 9 return f; | |
164 | 10 } | |
165 | 11 return f; | |
166 | 12 } | |
167 | ||
168 | with -ftrivial-auto-var-init, compiler will insert the following | |
169 | artificial initialization at line 4: | |
170 | f = .DEFERRED_INIT (f, 2); | |
171 | _1 = REALPART_EXPR <f>; | |
172 | ||
173 | without the following special handling, _1 = REALPART_EXPR <f> will | |
174 | be treated as the uninitialized use point, which is incorrect. (the | |
175 | real uninitialized use point is at line 11). */ | |
176 | if (is_gimple_assign (context) | |
177 | && (gimple_assign_rhs_code (context) == REALPART_EXPR | |
178 | || gimple_assign_rhs_code (context) == IMAGPART_EXPR)) | |
179 | { | |
180 | tree v = gimple_assign_rhs1 (context); | |
181 | if (TREE_CODE (TREE_OPERAND (v, 0)) == SSA_NAME | |
182 | && gimple_call_internal_p (SSA_NAME_DEF_STMT (TREE_OPERAND (v, 0)), | |
183 | IFN_DEFERRED_INIT)) | |
184 | return; | |
185 | } | |
186 | ||
50aa64d5 | 187 | /* Anonymous SSA_NAMEs shouldn't be uninitialized, but ssa_undefined_value_p |
6cb61e50 QZ |
188 | can return true if the def stmt of an anonymous SSA_NAME is |
189 | 1. A COMPLEX_EXPR created for conversion from scalar to complex. Use the | |
190 | underlying var of the COMPLEX_EXPRs real part in that case. See PR71581. | |
191 | ||
192 | Or | |
193 | ||
194 | 2. A call to .DEFERRED_INIT internal function. Since the original variable | |
195 | has been eliminated by optimziation, we need to get the variable name, | |
196 | and variable declaration location from this call. We recorded variable | |
197 | name into VAR_NAME_STR, and will get location info and record warning | |
198 | suppressed info to VAR_DEF_STMT, which is the .DEFERRED_INIT call. */ | |
199 | ||
200 | const char *var_name_str = NULL; | |
201 | gimple *var_def_stmt = NULL; | |
202 | ||
4e84e381 MS |
203 | if (!var && !SSA_NAME_VAR (t)) |
204 | { | |
6cb61e50 QZ |
205 | var_def_stmt = SSA_NAME_DEF_STMT (t); |
206 | ||
207 | if (is_gimple_assign (var_def_stmt) | |
208 | && gimple_assign_rhs_code (var_def_stmt) == COMPLEX_EXPR) | |
50aa64d5 | 209 | { |
6cb61e50 | 210 | tree v = gimple_assign_rhs1 (var_def_stmt); |
4e84e381 MS |
211 | if (TREE_CODE (v) == SSA_NAME |
212 | && has_undefined_value_p (v) | |
6cb61e50 | 213 | && zerop (gimple_assign_rhs2 (var_def_stmt))) |
4e84e381 | 214 | var = SSA_NAME_VAR (v); |
50aa64d5 | 215 | } |
6cb61e50 QZ |
216 | |
217 | if (gimple_call_internal_p (var_def_stmt, IFN_DEFERRED_INIT)) | |
218 | { | |
219 | /* Ignore the call to .DEFERRED_INIT that define the original | |
220 | var itself as the following case: | |
221 | temp = .DEFERRED_INIT (4, 2, “alt_reloc"); | |
222 | alt_reloc = temp; | |
223 | In order to avoid generating warning for the fake usage | |
224 | at alt_reloc = temp. | |
225 | */ | |
226 | tree lhs_var = NULL_TREE; | |
227 | tree lhs_var_name = NULL_TREE; | |
228 | const char *lhs_var_name_str = NULL; | |
229 | ||
230 | /* Get the variable name from the 3rd argument of call. */ | |
231 | tree var_name = gimple_call_arg (var_def_stmt, 2); | |
232 | var_name = TREE_OPERAND (TREE_OPERAND (var_name, 0), 0); | |
233 | var_name_str = TREE_STRING_POINTER (var_name); | |
234 | ||
235 | if (is_gimple_assign (context)) | |
236 | { | |
237 | if (TREE_CODE (gimple_assign_lhs (context)) == VAR_DECL) | |
238 | lhs_var = gimple_assign_lhs (context); | |
239 | else if (TREE_CODE (gimple_assign_lhs (context)) == SSA_NAME) | |
240 | lhs_var = SSA_NAME_VAR (gimple_assign_lhs (context)); | |
241 | } | |
242 | if (lhs_var | |
243 | && (lhs_var_name = DECL_NAME (lhs_var)) | |
244 | && (lhs_var_name_str = IDENTIFIER_POINTER (lhs_var_name)) | |
245 | && (strcmp (lhs_var_name_str, var_name_str) == 0)) | |
246 | return; | |
247 | gcc_assert (var_name_str && var_def_stmt); | |
248 | } | |
50aa64d5 JJ |
249 | } |
250 | ||
6cb61e50 | 251 | if (var == NULL_TREE && var_name_str == NULL) |
50aa64d5 JJ |
252 | return; |
253 | ||
4e84e381 MS |
254 | /* Avoid warning if we've already done so or if the warning has been |
255 | suppressed. */ | |
256 | if (((warning_suppressed_p (context, OPT_Wuninitialized) | |
257 | || (gimple_assign_single_p (context) | |
258 | && get_no_uninit_warning (gimple_assign_rhs1 (context))))) | |
6cb61e50 QZ |
259 | || (var && get_no_uninit_warning (var)) |
260 | || (var_name_str | |
261 | && warning_suppressed_p (var_def_stmt, OPT_Wuninitialized))) | |
c152901f AM |
262 | return; |
263 | ||
4e84e381 MS |
264 | /* Use either the location of the read statement or that of the PHI |
265 | argument, or that of the uninitialized variable, in that order, | |
266 | whichever is valid. */ | |
6cb61e50 | 267 | location_t location = UNKNOWN_LOCATION; |
4e84e381 | 268 | if (gimple_has_location (context)) |
e1ec47c4 | 269 | location = gimple_location (context); |
4e84e381 MS |
270 | else if (phi_arg_loc != UNKNOWN_LOCATION) |
271 | location = phi_arg_loc; | |
6cb61e50 | 272 | else if (var) |
e1ec47c4 | 273 | location = DECL_SOURCE_LOCATION (var); |
6cb61e50 QZ |
274 | else if (var_name_str) |
275 | location = gimple_location (var_def_stmt); | |
276 | ||
097f82ec | 277 | auto_diagnostic_group d; |
6cb61e50 QZ |
278 | gcc_assert (opt == OPT_Wuninitialized || opt == OPT_Wmaybe_uninitialized); |
279 | if (var) | |
280 | { | |
281 | if ((opt == OPT_Wuninitialized | |
282 | && !warning_at (location, opt, "%qD is used uninitialized", var)) | |
283 | || (opt == OPT_Wmaybe_uninitialized | |
284 | && !warning_at (location, opt, "%qD may be used uninitialized", | |
285 | var))) | |
286 | return; | |
287 | } | |
288 | else if (var_name_str) | |
289 | { | |
290 | if ((opt == OPT_Wuninitialized | |
291 | && !warning_at (location, opt, "%qs is used uninitialized", | |
292 | var_name_str)) | |
293 | || (opt == OPT_Wmaybe_uninitialized | |
294 | && !warning_at (location, opt, "%qs may be used uninitialized", | |
295 | var_name_str))) | |
296 | return; | |
297 | } | |
4e84e381 MS |
298 | |
299 | /* Avoid subsequent warnings for reads of the same variable again. */ | |
6cb61e50 QZ |
300 | if (var) |
301 | suppress_warning (var, opt); | |
302 | else if (var_name_str) | |
303 | suppress_warning (var_def_stmt, opt); | |
4e84e381 MS |
304 | |
305 | /* Issue a note pointing to the read variable unless the warning | |
306 | is at the same location. */ | |
6cb61e50 QZ |
307 | location_t var_loc = var ? DECL_SOURCE_LOCATION (var) |
308 | : gimple_location (var_def_stmt); | |
4e84e381 MS |
309 | if (location == var_loc) |
310 | return; | |
c152901f | 311 | |
6cb61e50 QZ |
312 | if (var) |
313 | inform (var_loc, "%qD was declared here", var); | |
314 | else if (var_name_str) | |
315 | inform (var_loc, "%qs was declared here", var_name_str); | |
c152901f AM |
316 | } |
317 | ||
e80facb4 RB |
318 | struct check_defs_data |
319 | { | |
320 | /* If we found any may-defs besides must-def clobbers. */ | |
321 | bool found_may_defs; | |
322 | }; | |
323 | ||
6aacd901 MS |
324 | /* Return true if STMT is a call to built-in function all of whose |
325 | by-reference arguments are const-qualified (i.e., the function can | |
326 | be assumed not to modify them). */ | |
327 | ||
328 | static bool | |
329 | builtin_call_nomodifying_p (gimple *stmt) | |
330 | { | |
331 | if (!gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) | |
332 | return false; | |
333 | ||
334 | tree fndecl = gimple_call_fndecl (stmt); | |
335 | if (!fndecl) | |
336 | return false; | |
337 | ||
338 | tree fntype = TREE_TYPE (fndecl); | |
339 | if (!fntype) | |
340 | return false; | |
341 | ||
342 | /* Check the called function's signature for non-constc pointers. | |
343 | If one is found, return false. */ | |
344 | unsigned argno = 0; | |
345 | tree argtype; | |
346 | function_args_iterator it; | |
347 | FOREACH_FUNCTION_ARGS (fntype, argtype, it) | |
348 | { | |
349 | if (VOID_TYPE_P (argtype)) | |
350 | return true; | |
351 | ||
352 | ++argno; | |
353 | ||
354 | if (!POINTER_TYPE_P (argtype)) | |
355 | continue; | |
356 | ||
357 | if (TYPE_READONLY (TREE_TYPE (argtype))) | |
358 | continue; | |
359 | ||
360 | return false; | |
361 | } | |
362 | ||
363 | /* If the number of actual arguments to the call is less than or | |
364 | equal to the number of parameters, return false. */ | |
365 | unsigned nargs = gimple_call_num_args (stmt); | |
366 | if (nargs <= argno) | |
367 | return false; | |
368 | ||
369 | /* Check arguments passed through the ellipsis in calls to variadic | |
370 | functions for pointers. If one is found that's a non-constant | |
371 | pointer, return false. */ | |
372 | for (; argno < nargs; ++argno) | |
373 | { | |
374 | tree arg = gimple_call_arg (stmt, argno); | |
375 | argtype = TREE_TYPE (arg); | |
376 | if (!POINTER_TYPE_P (argtype)) | |
377 | continue; | |
378 | ||
379 | if (TYPE_READONLY (TREE_TYPE (argtype))) | |
380 | continue; | |
381 | ||
382 | return false; | |
383 | } | |
384 | ||
385 | return true; | |
386 | } | |
387 | ||
fb85d6eb MS |
388 | /* If ARG is a FNDECL parameter declared with attribute access none or |
389 | write_only issue a warning for its read access via PTR. */ | |
390 | ||
391 | static void | |
392 | maybe_warn_read_write_only (tree fndecl, gimple *stmt, tree arg, tree ptr) | |
393 | { | |
394 | if (!fndecl) | |
395 | return; | |
396 | ||
397 | if (get_no_uninit_warning (arg)) | |
398 | return; | |
399 | ||
400 | tree fntype = TREE_TYPE (fndecl); | |
401 | if (!fntype) | |
402 | return; | |
403 | ||
404 | /* Initialize a map of attribute access specifications for arguments | |
027e3041 | 405 | to the function call. */ |
fb85d6eb MS |
406 | rdwr_map rdwr_idx; |
407 | init_attr_rdwr_indices (&rdwr_idx, TYPE_ATTRIBUTES (fntype)); | |
408 | ||
409 | unsigned argno = 0; | |
410 | tree parms = DECL_ARGUMENTS (fndecl); | |
411 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm), ++argno) | |
412 | { | |
413 | if (parm != arg) | |
414 | continue; | |
415 | ||
416 | const attr_access* access = rdwr_idx.get (argno); | |
417 | if (!access) | |
418 | break; | |
419 | ||
420 | if (access->mode != access_none | |
421 | && access->mode != access_write_only) | |
422 | continue; | |
423 | ||
b52b99b6 | 424 | location_t stmtloc = gimple_location (stmt); |
fb85d6eb MS |
425 | if (!warning_at (stmtloc, OPT_Wmaybe_uninitialized, |
426 | "%qE may be used uninitialized", ptr)) | |
427 | break; | |
428 | ||
429 | suppress_warning (arg, OPT_Wmaybe_uninitialized); | |
430 | ||
431 | const char* const access_str = | |
432 | TREE_STRING_POINTER (access->to_external_string ()); | |
433 | ||
434 | location_t parmloc = DECL_SOURCE_LOCATION (parm); | |
435 | inform (parmloc, "accessing argument %u of a function declared with " | |
436 | "attribute %<%s%>", | |
437 | argno + 1, access_str); | |
438 | ||
439 | break; | |
440 | } | |
441 | } | |
442 | ||
e80facb4 RB |
443 | /* Callback for walk_aliased_vdefs. */ |
444 | ||
445 | static bool | |
446 | check_defs (ao_ref *ref, tree vdef, void *data_) | |
447 | { | |
448 | check_defs_data *data = (check_defs_data *)data_; | |
449 | gimple *def_stmt = SSA_NAME_DEF_STMT (vdef); | |
2efe245b | 450 | |
a25e0b5e | 451 | /* Ignore the vdef if the definition statement is a call |
452 | to .DEFERRED_INIT function. */ | |
453 | if (gimple_call_internal_p (def_stmt, IFN_DEFERRED_INIT)) | |
454 | return false; | |
455 | ||
6cb61e50 QZ |
456 | /* For address taken variable, a temporary variable is added between |
457 | the variable and the call to .DEFERRED_INIT function as: | |
458 | _1 = .DEFERRED_INIT (4, 2, &"i1"[0]); | |
459 | i1 = _1; | |
460 | Ignore this vdef as well. */ | |
461 | if (is_gimple_assign (def_stmt) | |
462 | && gimple_assign_rhs_code (def_stmt) == SSA_NAME) | |
463 | { | |
464 | tree tmp_var = gimple_assign_rhs1 (def_stmt); | |
465 | if (gimple_call_internal_p (SSA_NAME_DEF_STMT (tmp_var), | |
466 | IFN_DEFERRED_INIT)) | |
467 | return false; | |
468 | } | |
469 | ||
2efe245b | 470 | /* The ASAN_MARK intrinsic doesn't modify the variable. */ |
e07d30fd MS |
471 | if (is_gimple_call (def_stmt)) |
472 | { | |
94c12ffa | 473 | /* The ASAN_MARK intrinsic doesn't modify the variable. */ |
e07d30fd MS |
474 | if (gimple_call_internal_p (def_stmt) |
475 | && gimple_call_internal_fn (def_stmt) == IFN_ASAN_MARK) | |
94c12ffa | 476 | return false; |
e07d30fd MS |
477 | |
478 | if (tree fndecl = gimple_call_fndecl (def_stmt)) | |
94c12ffa MS |
479 | { |
480 | /* Some sanitizer calls pass integer arguments to built-ins | |
481 | that expect pointets. Avoid using gimple_call_builtin_p() | |
482 | which fails for such calls. */ | |
483 | if (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) | |
484 | { | |
485 | built_in_function fncode = DECL_FUNCTION_CODE (fndecl); | |
486 | if (fncode > BEGIN_SANITIZER_BUILTINS | |
487 | && fncode < END_SANITIZER_BUILTINS) | |
488 | return false; | |
489 | } | |
490 | } | |
e07d30fd | 491 | } |
2efe245b MS |
492 | |
493 | /* End of VLA scope is not a kill. */ | |
494 | if (gimple_call_builtin_p (def_stmt, BUILT_IN_STACK_RESTORE)) | |
495 | return false; | |
496 | ||
e80facb4 RB |
497 | /* If this is a clobber then if it is not a kill walk past it. */ |
498 | if (gimple_clobber_p (def_stmt)) | |
499 | { | |
500 | if (stmt_kills_ref_p (def_stmt, ref)) | |
501 | return true; | |
502 | return false; | |
503 | } | |
2efe245b | 504 | |
6aacd901 MS |
505 | if (builtin_call_nomodifying_p (def_stmt)) |
506 | return false; | |
507 | ||
e80facb4 RB |
508 | /* Found a may-def on this path. */ |
509 | data->found_may_defs = true; | |
510 | return true; | |
511 | } | |
512 | ||
027e3041 | 513 | /* Counters and limits controlling the depth of analysis and |
b825a228 MS |
514 | strictness of the warning. */ |
515 | struct wlimits | |
516 | { | |
517 | /* Number of VDEFs encountered. */ | |
518 | unsigned int vdef_cnt; | |
519 | /* Number of statements examined by walk_aliased_vdefs. */ | |
520 | unsigned int oracle_cnt; | |
521 | /* Limit on the number of statements visited by walk_aliased_vdefs. */ | |
522 | unsigned limit; | |
523 | /* Set when basic block with statement is executed unconditionally. */ | |
524 | bool always_executed; | |
525 | /* Set to issue -Wmaybe-uninitialized. */ | |
526 | bool wmaybe_uninit; | |
527 | }; | |
528 | ||
529 | /* Determine if REF references an uninitialized operand and diagnose | |
fb85d6eb MS |
530 | it if so. STMS is the referencing statement. LHS is the result |
531 | of the access and may be null. RHS is the variable referenced by | |
532 | the access; it may not be null. */ | |
b825a228 MS |
533 | |
534 | static tree | |
535 | maybe_warn_operand (ao_ref &ref, gimple *stmt, tree lhs, tree rhs, | |
536 | wlimits &wlims) | |
537 | { | |
538 | bool has_bit_insert = false; | |
539 | use_operand_p luse_p; | |
540 | imm_use_iterator liter; | |
541 | ||
e9e2bad7 | 542 | if (get_no_uninit_warning (rhs)) |
b825a228 MS |
543 | return NULL_TREE; |
544 | ||
545 | /* Do not warn if the base was marked so or this is a | |
546 | hard register var. */ | |
547 | tree base = ao_ref_base (&ref); | |
548 | if ((VAR_P (base) | |
549 | && DECL_HARD_REGISTER (base)) | |
e9e2bad7 | 550 | || get_no_uninit_warning (base)) |
b825a228 MS |
551 | return NULL_TREE; |
552 | ||
1121e495 MS |
553 | /* Do not warn if the access is zero size or if it's fully outside |
554 | the object. */ | |
b825a228 | 555 | poly_int64 decl_size; |
1121e495 MS |
556 | if (known_size_p (ref.size) |
557 | && known_eq (ref.max_size, ref.size) | |
558 | && (known_eq (ref.size, 0) | |
559 | || known_le (ref.offset + ref.size, 0))) | |
560 | return NULL_TREE; | |
561 | ||
b825a228 | 562 | if (DECL_P (base) |
1121e495 MS |
563 | && known_ge (ref.offset, 0) |
564 | && DECL_SIZE (base) | |
565 | && poly_int_tree_p (DECL_SIZE (base), &decl_size) | |
566 | && known_le (decl_size, ref.offset)) | |
b825a228 MS |
567 | return NULL_TREE; |
568 | ||
569 | /* Do not warn if the result of the access is then used for | |
570 | a BIT_INSERT_EXPR. */ | |
571 | if (lhs && TREE_CODE (lhs) == SSA_NAME) | |
572 | FOR_EACH_IMM_USE_FAST (luse_p, liter, lhs) | |
573 | { | |
574 | gimple *use_stmt = USE_STMT (luse_p); | |
575 | /* BIT_INSERT_EXPR first operand should not be considered | |
576 | a use for the purpose of uninit warnings. */ | |
577 | if (gassign *ass = dyn_cast <gassign *> (use_stmt)) | |
578 | { | |
579 | if (gimple_assign_rhs_code (ass) == BIT_INSERT_EXPR | |
580 | && luse_p->use == gimple_assign_rhs1_ptr (ass)) | |
581 | { | |
582 | has_bit_insert = true; | |
583 | break; | |
584 | } | |
585 | } | |
586 | } | |
587 | ||
588 | if (has_bit_insert) | |
589 | return NULL_TREE; | |
590 | ||
591 | /* Limit the walking to a constant number of stmts after | |
592 | we overcommit quadratic behavior for small functions | |
593 | and O(n) behavior. */ | |
594 | if (wlims.oracle_cnt > 128 * 128 | |
595 | && wlims.oracle_cnt > wlims.vdef_cnt * 2) | |
596 | wlims.limit = 32; | |
597 | ||
598 | check_defs_data data; | |
599 | bool fentry_reached = false; | |
600 | data.found_may_defs = false; | |
601 | tree use = gimple_vuse (stmt); | |
602 | if (!use) | |
603 | return NULL_TREE; | |
604 | int res = walk_aliased_vdefs (&ref, use, | |
605 | check_defs, &data, NULL, | |
606 | &fentry_reached, wlims.limit); | |
607 | if (res == -1) | |
608 | { | |
609 | wlims.oracle_cnt += wlims.limit; | |
610 | return NULL_TREE; | |
611 | } | |
612 | ||
613 | wlims.oracle_cnt += res; | |
614 | if (data.found_may_defs) | |
615 | return NULL_TREE; | |
616 | ||
617 | bool found_alloc = false; | |
618 | ||
619 | if (fentry_reached) | |
620 | { | |
621 | if (TREE_CODE (base) == MEM_REF) | |
622 | base = TREE_OPERAND (base, 0); | |
623 | ||
624 | /* Follow the chain of SSA_NAME assignments looking for an alloca | |
625 | call (or VLA) or malloc/realloc, or for decls. If any is found | |
626 | (and in the latter case, the operand is a local variable) issue | |
627 | a warning. */ | |
628 | while (TREE_CODE (base) == SSA_NAME) | |
629 | { | |
630 | gimple *def_stmt = SSA_NAME_DEF_STMT (base); | |
631 | ||
632 | if (is_gimple_call (def_stmt) | |
633 | && gimple_call_builtin_p (def_stmt)) | |
634 | { | |
635 | /* Detect uses of uninitialized alloca/VLAs. */ | |
636 | tree fndecl = gimple_call_fndecl (def_stmt); | |
637 | const built_in_function fncode = DECL_FUNCTION_CODE (fndecl); | |
638 | if (fncode == BUILT_IN_ALLOCA | |
639 | || fncode == BUILT_IN_ALLOCA_WITH_ALIGN | |
640 | || fncode == BUILT_IN_MALLOC) | |
641 | found_alloc = true; | |
642 | break; | |
643 | } | |
644 | ||
645 | if (!is_gimple_assign (def_stmt)) | |
646 | break; | |
647 | ||
648 | tree_code code = gimple_assign_rhs_code (def_stmt); | |
649 | if (code != ADDR_EXPR && code != POINTER_PLUS_EXPR) | |
650 | break; | |
651 | ||
652 | base = gimple_assign_rhs1 (def_stmt); | |
653 | if (TREE_CODE (base) == ADDR_EXPR) | |
654 | base = TREE_OPERAND (base, 0); | |
655 | ||
656 | if (DECL_P (base) | |
657 | || TREE_CODE (base) == COMPONENT_REF) | |
658 | rhs = base; | |
659 | ||
660 | if (TREE_CODE (base) == MEM_REF) | |
661 | base = TREE_OPERAND (base, 0); | |
662 | ||
663 | if (tree ba = get_base_address (base)) | |
664 | base = ba; | |
665 | } | |
666 | ||
667 | /* Replace the RHS expression with BASE so that it | |
668 | refers to it in the diagnostic (instead of to | |
669 | '<unknown>'). */ | |
670 | if (DECL_P (base) | |
671 | && EXPR_P (rhs) | |
672 | && TREE_CODE (rhs) != COMPONENT_REF) | |
673 | rhs = base; | |
674 | } | |
675 | ||
676 | /* Do not warn if it can be initialized outside this function. | |
677 | If we did not reach function entry then we found killing | |
678 | clobbers on all paths to entry. */ | |
fb85d6eb MS |
679 | if (!found_alloc && fentry_reached) |
680 | { | |
681 | if (TREE_CODE (base) == SSA_NAME) | |
682 | { | |
683 | tree var = SSA_NAME_VAR (base); | |
684 | if (var && TREE_CODE (var) == PARM_DECL) | |
685 | { | |
686 | maybe_warn_read_write_only (cfun->decl, stmt, var, rhs); | |
687 | return NULL_TREE; | |
688 | } | |
689 | } | |
690 | ||
691 | if (!VAR_P (base) | |
692 | || is_global_var (base)) | |
693 | /* ??? We'd like to use ref_may_alias_global_p but that | |
694 | excludes global readonly memory and thus we get bogus | |
695 | warnings from p = cond ? "a" : "b" for example. */ | |
696 | return NULL_TREE; | |
697 | } | |
b825a228 MS |
698 | |
699 | /* Strip the address-of expression from arrays passed to functions. */ | |
700 | if (TREE_CODE (rhs) == ADDR_EXPR) | |
701 | rhs = TREE_OPERAND (rhs, 0); | |
702 | ||
703 | /* Check again since RHS may have changed above. */ | |
e9e2bad7 | 704 | if (get_no_uninit_warning (rhs)) |
b825a228 MS |
705 | return NULL_TREE; |
706 | ||
707 | /* Avoid warning about empty types such as structs with no members. | |
708 | The first_field() test is important for C++ where the predicate | |
709 | alone isn't always sufficient. */ | |
710 | tree rhstype = TREE_TYPE (rhs); | |
8b75204b MS |
711 | if (POINTER_TYPE_P (rhstype)) |
712 | rhstype = TREE_TYPE (rhstype); | |
3072125a | 713 | if (is_empty_type (rhstype)) |
b825a228 MS |
714 | return NULL_TREE; |
715 | ||
716 | bool warned = false; | |
717 | /* We didn't find any may-defs so on all paths either | |
718 | reached function entry or a killing clobber. */ | |
b52b99b6 | 719 | location_t location = gimple_location (stmt); |
b825a228 MS |
720 | if (wlims.always_executed) |
721 | { | |
722 | if (warning_at (location, OPT_Wuninitialized, | |
6d3bab5d | 723 | "%qE is used uninitialized", rhs)) |
b825a228 MS |
724 | { |
725 | /* ??? This is only effective for decls as in | |
726 | gcc.dg/uninit-B-O0.c. Avoid doing this for maybe-uninit | |
727 | uses or accesses by functions as it may hide important | |
728 | locations. */ | |
729 | if (lhs) | |
e9e2bad7 | 730 | set_no_uninit_warning (rhs); |
b825a228 MS |
731 | warned = true; |
732 | } | |
733 | } | |
734 | else if (wlims.wmaybe_uninit) | |
735 | warned = warning_at (location, OPT_Wmaybe_uninitialized, | |
6d3bab5d | 736 | "%qE may be used uninitialized", rhs); |
b825a228 MS |
737 | |
738 | return warned ? base : NULL_TREE; | |
739 | } | |
740 | ||
741 | ||
742 | /* Diagnose passing addresses of uninitialized objects to either const | |
743 | pointer arguments to functions, or to functions declared with attribute | |
744 | access implying read access to those objects. */ | |
745 | ||
746 | static void | |
0c9687d0 | 747 | maybe_warn_pass_by_reference (gcall *stmt, wlimits &wlims) |
b825a228 MS |
748 | { |
749 | if (!wlims.wmaybe_uninit) | |
750 | return; | |
751 | ||
752 | unsigned nargs = gimple_call_num_args (stmt); | |
753 | if (!nargs) | |
754 | return; | |
755 | ||
756 | tree fndecl = gimple_call_fndecl (stmt); | |
757 | tree fntype = gimple_call_fntype (stmt); | |
758 | if (!fntype) | |
759 | return; | |
760 | ||
0c9687d0 JH |
761 | /* Const function do not read their arguments. */ |
762 | if (gimple_call_flags (stmt) & ECF_CONST) | |
763 | return; | |
764 | ||
b825a228 MS |
765 | const built_in_function fncode |
766 | = (fndecl && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL) | |
767 | ? DECL_FUNCTION_CODE (fndecl) : (built_in_function)BUILT_IN_LAST); | |
768 | ||
769 | if (fncode == BUILT_IN_MEMCPY || fncode == BUILT_IN_MEMMOVE) | |
770 | /* Avoid diagnosing calls to raw memory functions (this is overly | |
771 | permissive; consider tightening it up). */ | |
772 | return; | |
773 | ||
774 | /* Save the current warning setting and replace it either a "maybe" | |
775 | when passing addresses of uninitialized variables to const-qualified | |
776 | pointers or arguments declared with attribute read_write, or with | |
777 | a "certain" when passing them to arguments declared with attribute | |
778 | read_only. */ | |
779 | const bool save_always_executed = wlims.always_executed; | |
780 | ||
72be80e4 | 781 | /* Initialize a map of attribute access specifications for arguments |
027e3041 | 782 | to the function call. */ |
b825a228 | 783 | rdwr_map rdwr_idx; |
6450f073 | 784 | init_attr_rdwr_indices (&rdwr_idx, TYPE_ATTRIBUTES (fntype)); |
b825a228 MS |
785 | |
786 | tree argtype; | |
787 | unsigned argno = 0; | |
788 | function_args_iterator it; | |
789 | ||
790 | FOREACH_FUNCTION_ARGS (fntype, argtype, it) | |
791 | { | |
792 | ++argno; | |
793 | ||
e07a876c RB |
794 | if (argno > nargs) |
795 | break; | |
796 | ||
b825a228 MS |
797 | if (!POINTER_TYPE_P (argtype)) |
798 | continue; | |
799 | ||
800 | tree access_size = NULL_TREE; | |
72be80e4 | 801 | const attr_access* access = rdwr_idx.get (argno - 1); |
b825a228 MS |
802 | if (access) |
803 | { | |
d14c547a MS |
804 | if (access->mode == access_none |
805 | || access->mode == access_write_only) | |
b825a228 | 806 | continue; |
72be80e4 MS |
807 | |
808 | if (access->mode == access_deferred | |
809 | && !TYPE_READONLY (TREE_TYPE (argtype))) | |
810 | continue; | |
811 | ||
d14c547a | 812 | if (save_always_executed && access->mode == access_read_only) |
b825a228 MS |
813 | /* Attribute read_only arguments imply read access. */ |
814 | wlims.always_executed = true; | |
815 | else | |
816 | /* Attribute read_write arguments are documented as requiring | |
817 | initialized objects but it's expected that aggregates may | |
818 | be only partially initialized regardless. */ | |
819 | wlims.always_executed = false; | |
820 | ||
821 | if (access->sizarg < nargs) | |
822 | access_size = gimple_call_arg (stmt, access->sizarg); | |
823 | } | |
824 | else if (!TYPE_READONLY (TREE_TYPE (argtype))) | |
825 | continue; | |
826 | else if (save_always_executed && fncode != BUILT_IN_LAST) | |
827 | /* Const-qualified arguments to built-ins imply read access. */ | |
828 | wlims.always_executed = true; | |
829 | else | |
830 | /* Const-qualified arguments to ordinary functions imply a likely | |
831 | (but not definitive) read access. */ | |
832 | wlims.always_executed = false; | |
833 | ||
0c9687d0 | 834 | /* Ignore args we are not going to read from. */ |
d70ef656 JH |
835 | if (gimple_call_arg_flags (stmt, argno - 1) |
836 | & (EAF_UNUSED | EAF_NO_DIRECT_READ)) | |
0c9687d0 JH |
837 | continue; |
838 | ||
b825a228 | 839 | tree arg = gimple_call_arg (stmt, argno - 1); |
9816f509 MS |
840 | if (!POINTER_TYPE_P (TREE_TYPE (arg))) |
841 | /* Avoid actual arguments with invalid types. */ | |
842 | continue; | |
b825a228 MS |
843 | |
844 | ao_ref ref; | |
845 | ao_ref_init_from_ptr_and_size (&ref, arg, access_size); | |
846 | tree argbase = maybe_warn_operand (ref, stmt, NULL_TREE, arg, wlims); | |
847 | if (!argbase) | |
848 | continue; | |
849 | ||
72be80e4 | 850 | if (access && access->mode != access_deferred) |
b825a228 | 851 | { |
72be80e4 MS |
852 | const char* const access_str = |
853 | TREE_STRING_POINTER (access->to_external_string ()); | |
b825a228 MS |
854 | |
855 | if (fndecl) | |
856 | { | |
857 | location_t loc = DECL_SOURCE_LOCATION (fndecl); | |
72be80e4 MS |
858 | inform (loc, "in a call to %qD declared with " |
859 | "attribute %<%s%> here", fndecl, access_str); | |
b825a228 MS |
860 | } |
861 | else | |
862 | { | |
863 | /* Handle calls through function pointers. */ | |
864 | location_t loc = gimple_location (stmt); | |
865 | inform (loc, "in a call to %qT declared with " | |
72be80e4 | 866 | "attribute %<%s%>", fntype, access_str); |
b825a228 MS |
867 | } |
868 | } | |
b825a228 MS |
869 | else |
870 | { | |
72be80e4 MS |
871 | /* For a declaration with no relevant attribute access create |
872 | a dummy object and use the formatting function to avoid | |
873 | having to complicate things here. */ | |
874 | attr_access ptr_access = { }; | |
875 | if (!access) | |
876 | access = &ptr_access; | |
877 | const std::string argtypestr = access->array_as_string (argtype); | |
878 | if (fndecl) | |
879 | { | |
880 | location_t loc (DECL_SOURCE_LOCATION (fndecl)); | |
baad4c48 | 881 | inform (loc, "by argument %u of type %s to %qD " |
72be80e4 MS |
882 | "declared here", |
883 | argno, argtypestr.c_str (), fndecl); | |
884 | } | |
885 | else | |
886 | { | |
887 | /* Handle calls through function pointers. */ | |
888 | location_t loc (gimple_location (stmt)); | |
baad4c48 | 889 | inform (loc, "by argument %u of type %s to %qT", |
72be80e4 MS |
890 | argno, argtypestr.c_str (), fntype); |
891 | } | |
b825a228 MS |
892 | } |
893 | ||
894 | if (DECL_P (argbase)) | |
895 | { | |
896 | location_t loc = DECL_SOURCE_LOCATION (argbase); | |
897 | inform (loc, "%qD declared here", argbase); | |
898 | } | |
899 | } | |
900 | ||
901 | wlims.always_executed = save_always_executed; | |
902 | } | |
903 | ||
66030d68 RB |
904 | /* Warn about an uninitialized PHI argument on the fallthru path to |
905 | an always executed block BB. */ | |
906 | ||
907 | static void | |
908 | warn_uninit_phi_uses (basic_block bb) | |
909 | { | |
910 | edge_iterator ei; | |
911 | edge e, found = NULL, found_back = NULL; | |
912 | /* Look for a fallthru and possibly a single backedge. */ | |
913 | FOR_EACH_EDGE (e, ei, bb->preds) | |
914 | { | |
915 | /* Ignore backedges. */ | |
916 | if (dominated_by_p (CDI_DOMINATORS, e->src, bb)) | |
917 | { | |
918 | if (found_back) | |
919 | { | |
920 | found = NULL; | |
921 | break; | |
922 | } | |
923 | found_back = e; | |
924 | continue; | |
925 | } | |
926 | if (found) | |
927 | { | |
928 | found = NULL; | |
929 | break; | |
930 | } | |
931 | found = e; | |
932 | } | |
933 | if (!found) | |
934 | return; | |
935 | ||
936 | basic_block succ = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); | |
937 | for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); | |
938 | gsi_next (&si)) | |
939 | { | |
940 | gphi *phi = si.phi (); | |
941 | tree def = PHI_ARG_DEF_FROM_EDGE (phi, found); | |
942 | if (TREE_CODE (def) != SSA_NAME | |
943 | || !SSA_NAME_IS_DEFAULT_DEF (def) | |
944 | || virtual_operand_p (def)) | |
945 | continue; | |
946 | /* If there's a default def on the fallthru edge PHI | |
947 | value and there's a use that post-dominates entry | |
948 | then that use is uninitialized and we can warn. */ | |
949 | imm_use_iterator iter; | |
950 | use_operand_p use_p; | |
951 | gimple *use_stmt = NULL; | |
952 | FOR_EACH_IMM_USE_FAST (use_p, iter, gimple_phi_result (phi)) | |
953 | { | |
954 | use_stmt = USE_STMT (use_p); | |
955 | if (gimple_location (use_stmt) != UNKNOWN_LOCATION | |
956 | && dominated_by_p (CDI_POST_DOMINATORS, succ, | |
957 | gimple_bb (use_stmt)) | |
958 | /* If we found a non-fallthru edge make sure the | |
959 | use is inside the loop, otherwise the backedge | |
960 | can serve as initialization. */ | |
961 | && (!found_back | |
962 | || dominated_by_p (CDI_DOMINATORS, found_back->src, | |
963 | gimple_bb (use_stmt)))) | |
964 | break; | |
965 | use_stmt = NULL; | |
966 | } | |
967 | if (use_stmt) | |
6cb61e50 QZ |
968 | warn_uninit (OPT_Wuninitialized, def, |
969 | SSA_NAME_VAR (def), use_stmt); | |
66030d68 RB |
970 | } |
971 | } | |
b825a228 | 972 | |
4e84e381 MS |
973 | /* Issue warnings about reads of uninitialized variables. WMAYBE_UNINIT |
974 | is true to issue -Wmaybe-uninitialized, otherwise -Wuninitialized. */ | |
975 | ||
976 | static void | |
b825a228 | 977 | warn_uninitialized_vars (bool wmaybe_uninit) |
c152901f | 978 | { |
027e3041 | 979 | /* Counters and limits controlling the depth of the warning. */ |
b825a228 MS |
980 | wlimits wlims = { }; |
981 | wlims.wmaybe_uninit = wmaybe_uninit; | |
982 | ||
f71abacf RB |
983 | auto_bb_flag ft_reachable (cfun); |
984 | ||
985 | /* Mark blocks that are always executed when we ignore provably | |
a1cd4d52 | 986 | not executed and EH and abnormal edges. */ |
f71abacf RB |
987 | basic_block bb = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
988 | while (!(bb->flags & ft_reachable)) | |
989 | { | |
990 | bb->flags |= ft_reachable; | |
a1cd4d52 RB |
991 | edge e = find_fallthru_edge (bb->succs); |
992 | if (e && e->flags & EDGE_EXECUTABLE) | |
993 | { | |
994 | bb = e->dest; | |
995 | continue; | |
996 | } | |
f71abacf RB |
997 | /* Find a single executable edge. */ |
998 | edge_iterator ei; | |
a1cd4d52 | 999 | edge ee = NULL; |
f71abacf RB |
1000 | FOR_EACH_EDGE (e, ei, bb->succs) |
1001 | if (e->flags & EDGE_EXECUTABLE) | |
1002 | { | |
1003 | if (!ee) | |
1004 | ee = e; | |
1005 | else | |
1006 | { | |
1007 | ee = NULL; | |
1008 | break; | |
1009 | } | |
1010 | } | |
1011 | if (ee) | |
1012 | bb = ee->dest; | |
1013 | else | |
ad08894e RB |
1014 | bb = get_immediate_dominator (CDI_POST_DOMINATORS, bb); |
1015 | if (!bb || bb->index == EXIT_BLOCK) | |
1016 | break; | |
f71abacf RB |
1017 | } |
1018 | ||
11cd3bed | 1019 | FOR_EACH_BB_FN (bb, cfun) |
c152901f | 1020 | { |
f71abacf RB |
1021 | wlims.always_executed = (bb->flags & ft_reachable); |
1022 | bb->flags &= ~ft_reachable; | |
1023 | ||
0f58ba4d RB |
1024 | edge_iterator ei; |
1025 | edge e; | |
1026 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1027 | if (e->flags & EDGE_EXECUTABLE) | |
1028 | break; | |
1029 | /* Skip unreachable blocks. For early analysis we use VN to | |
1030 | determine edge executability when wmaybe_uninit. */ | |
1031 | if (!e) | |
1032 | continue; | |
1033 | ||
66030d68 RB |
1034 | if (wlims.always_executed) |
1035 | warn_uninit_phi_uses (bb); | |
1036 | ||
f71abacf | 1037 | gimple_stmt_iterator gsi; |
c152901f AM |
1038 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
1039 | { | |
355fe088 | 1040 | gimple *stmt = gsi_stmt (gsi); |
a25e0b5e | 1041 | |
1042 | /* The call is an artificial use, will not provide meaningful | |
1043 | error message. If the result of the call is used somewhere | |
1044 | else, we warn there instead. */ | |
1045 | if (gimple_call_internal_p (stmt, IFN_DEFERRED_INIT)) | |
1046 | continue; | |
1047 | ||
c152901f AM |
1048 | if (is_gimple_debug (stmt)) |
1049 | continue; | |
1050 | ||
1051 | /* We only do data flow with SSA_NAMEs, so that's all we | |
1052 | can warn about. */ | |
4e84e381 MS |
1053 | use_operand_p use_p; |
1054 | ssa_op_iter op_iter; | |
c152901f AM |
1055 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, op_iter, SSA_OP_USE) |
1056 | { | |
d07f8c59 | 1057 | /* BIT_INSERT_EXPR first operand should not be considered |
f71abacf | 1058 | a use for the purpose of uninit warnings. */ |
d07f8c59 RB |
1059 | if (gassign *ass = dyn_cast <gassign *> (stmt)) |
1060 | { | |
1061 | if (gimple_assign_rhs_code (ass) == BIT_INSERT_EXPR | |
1062 | && use_p->use == gimple_assign_rhs1_ptr (ass)) | |
1063 | continue; | |
1064 | } | |
4e84e381 | 1065 | tree use = USE_FROM_PTR (use_p); |
b825a228 | 1066 | if (wlims.always_executed) |
6cb61e50 QZ |
1067 | warn_uninit (OPT_Wuninitialized, use, |
1068 | SSA_NAME_VAR (use), stmt); | |
f71abacf | 1069 | else if (wlims.wmaybe_uninit) |
6cb61e50 QZ |
1070 | warn_uninit (OPT_Wmaybe_uninitialized, use, |
1071 | SSA_NAME_VAR (use), stmt); | |
c152901f AM |
1072 | } |
1073 | ||
e80facb4 RB |
1074 | /* For limiting the alias walk below we count all |
1075 | vdefs in the function. */ | |
1076 | if (gimple_vdef (stmt)) | |
b825a228 | 1077 | wlims.vdef_cnt++; |
e80facb4 | 1078 | |
0c9687d0 JH |
1079 | if (gcall *call = dyn_cast <gcall *> (stmt)) |
1080 | maybe_warn_pass_by_reference (call, wlims); | |
b825a228 MS |
1081 | else if (gimple_assign_load_p (stmt) |
1082 | && gimple_has_location (stmt)) | |
c152901f AM |
1083 | { |
1084 | tree rhs = gimple_assign_rhs1 (stmt); | |
6d20bf18 | 1085 | tree lhs = gimple_assign_lhs (stmt); |
e80facb4 RB |
1086 | |
1087 | ao_ref ref; | |
1088 | ao_ref_init (&ref, rhs); | |
b825a228 MS |
1089 | tree var = maybe_warn_operand (ref, stmt, lhs, rhs, wlims); |
1090 | if (!var) | |
d21a8e3b | 1091 | continue; |
c152901f | 1092 | |
b825a228 | 1093 | if (DECL_P (var)) |
e80facb4 | 1094 | { |
b825a228 MS |
1095 | location_t loc = DECL_SOURCE_LOCATION (var); |
1096 | inform (loc, "%qD declared here", var); | |
e80facb4 | 1097 | } |
c152901f AM |
1098 | } |
1099 | } | |
1100 | } | |
c152901f AM |
1101 | } |
1102 | ||
927734cf XDL |
1103 | /* Checks if the operand OPND of PHI is defined by |
1104 | another phi with one operand defined by this PHI, | |
ac0e4fde | 1105 | but the rest operands are all defined. If yes, |
026c3cfd | 1106 | returns true to skip this operand as being |
ac0e4fde | 1107 | redundant. Can be enhanced to be more general. */ |
34f97b94 XDL |
1108 | |
1109 | static bool | |
355fe088 | 1110 | can_skip_redundant_opnd (tree opnd, gimple *phi) |
34f97b94 | 1111 | { |
4e84e381 MS |
1112 | tree phi_def = gimple_phi_result (phi); |
1113 | gimple *op_def = SSA_NAME_DEF_STMT (opnd); | |
34f97b94 XDL |
1114 | if (gimple_code (op_def) != GIMPLE_PHI) |
1115 | return false; | |
4e84e381 MS |
1116 | |
1117 | unsigned n = gimple_phi_num_args (op_def); | |
1118 | for (unsigned i = 0; i < n; ++i) | |
34f97b94 XDL |
1119 | { |
1120 | tree op = gimple_phi_arg_def (op_def, i); | |
1121 | if (TREE_CODE (op) != SSA_NAME) | |
5e48d8a0 | 1122 | continue; |
ba7e83f8 | 1123 | if (op != phi_def && uninit_undefined_value_p (op)) |
5e48d8a0 | 1124 | return false; |
34f97b94 XDL |
1125 | } |
1126 | ||
1127 | return true; | |
1128 | } | |
1129 | ||
94c12ffa MS |
1130 | /* Return a bitset holding the positions of arguments in PHI with empty |
1131 | (or possibly empty) definitions. */ | |
34f97b94 XDL |
1132 | |
1133 | static unsigned | |
538dd0b7 | 1134 | compute_uninit_opnds_pos (gphi *phi) |
34f97b94 | 1135 | { |
34f97b94 XDL |
1136 | unsigned uninit_opnds = 0; |
1137 | ||
4e84e381 | 1138 | unsigned n = gimple_phi_num_args (phi); |
98d30e4f | 1139 | /* Bail out for phi with too many args. */ |
cd1216d5 | 1140 | if (n > uninit_analysis::func_t::max_phi_args) |
98d30e4f | 1141 | return 0; |
34f97b94 | 1142 | |
4e84e381 | 1143 | for (unsigned i = 0; i < n; ++i) |
34f97b94 XDL |
1144 | { |
1145 | tree op = gimple_phi_arg_def (phi, i); | |
1146 | if (TREE_CODE (op) == SSA_NAME | |
5e48d8a0 ML |
1147 | && uninit_undefined_value_p (op) |
1148 | && !can_skip_redundant_opnd (op, phi)) | |
e7d764f3 | 1149 | { |
5e48d8a0 | 1150 | if (cfun->has_nonlocal_label || cfun->calls_setjmp) |
e7d764f3 | 1151 | { |
aea0101d RB |
1152 | /* Ignore SSA_NAMEs that appear on abnormal edges |
1153 | somewhere. */ | |
1154 | if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op)) | |
1155 | continue; | |
e7d764f3 JJ |
1156 | } |
1157 | MASK_SET_BIT (uninit_opnds, i); | |
1158 | } | |
34f97b94 | 1159 | } |
4a8f98fa RB |
1160 | /* If we have recorded guarded uses of may-uninit values mask those. */ |
1161 | if (auto *def_mask = defined_args->get (phi)) | |
1162 | uninit_opnds &= ~*def_mask; | |
34f97b94 XDL |
1163 | return uninit_opnds; |
1164 | } | |
1165 | ||
94c12ffa MS |
1166 | /* Function object type used to determine whether an expression |
1167 | is of interest to the predicate analyzer. */ | |
34f97b94 | 1168 | |
cd1216d5 | 1169 | struct uninit_undef_val_t: public uninit_analysis::func_t |
34f97b94 | 1170 | { |
94c12ffa MS |
1171 | virtual unsigned phi_arg_set (gphi *) override; |
1172 | }; | |
34f97b94 | 1173 | |
94c12ffa | 1174 | /* Return a bitset of PHI arguments of interest. */ |
34f97b94 | 1175 | |
94c12ffa MS |
1176 | unsigned |
1177 | uninit_undef_val_t::phi_arg_set (gphi *phi) | |
34f97b94 | 1178 | { |
94c12ffa | 1179 | return compute_uninit_opnds_pos (phi); |
34f97b94 XDL |
1180 | } |
1181 | ||
8a63343a RB |
1182 | /* sort helper for find_uninit_use. */ |
1183 | ||
1184 | static int | |
1185 | cand_cmp (const void *a, const void *b, void *data) | |
1186 | { | |
1187 | int *bb_to_rpo = (int *)data; | |
1188 | const gimple *sa = *(const gimple * const *)a; | |
1189 | const gimple *sb = *(const gimple * const *)b; | |
1190 | if (bb_to_rpo[gimple_bb (sa)->index] < bb_to_rpo[gimple_bb (sb)->index]) | |
1191 | return -1; | |
1192 | else if (bb_to_rpo[gimple_bb (sa)->index] > bb_to_rpo[gimple_bb (sb)->index]) | |
1193 | return 1; | |
1194 | return 0; | |
1195 | } | |
1196 | ||
94c12ffa MS |
1197 | /* Searches through all uses of a potentially |
1198 | uninitialized variable defined by PHI and returns a use | |
1199 | statement if the use is not properly guarded. It returns | |
1200 | NULL if all uses are guarded. UNINIT_OPNDS is a bitvector | |
4a8f98fa | 1201 | holding the position(s) of uninit PHI operands. */ |
34f97b94 | 1202 | |
94c12ffa | 1203 | static gimple * |
8a63343a | 1204 | find_uninit_use (gphi *phi, unsigned uninit_opnds, int *bb_to_rpo) |
34f97b94 | 1205 | { |
94c12ffa MS |
1206 | /* The Boolean predicate guarding the PHI definition. Initialized |
1207 | lazily from PHI in the first call to is_use_guarded() and cached | |
1208 | for subsequent iterations. */ | |
1209 | uninit_undef_val_t eval; | |
cd1216d5 | 1210 | uninit_analysis def_preds (eval); |
34f97b94 | 1211 | |
8a63343a RB |
1212 | /* First process PHIs and record other candidates. */ |
1213 | auto_vec<gimple *, 64> cands; | |
94c12ffa MS |
1214 | use_operand_p use_p; |
1215 | imm_use_iterator iter; | |
1216 | tree phi_result = gimple_phi_result (phi); | |
1217 | FOR_EACH_IMM_USE_FAST (use_p, iter, phi_result) | |
34f97b94 | 1218 | { |
94c12ffa MS |
1219 | gimple *use_stmt = USE_STMT (use_p); |
1220 | if (is_gimple_debug (use_stmt)) | |
5e48d8a0 | 1221 | continue; |
34f97b94 | 1222 | |
94c12ffa | 1223 | if (gphi *use_phi = dyn_cast<gphi *> (use_stmt)) |
c77fae1c | 1224 | { |
8a63343a RB |
1225 | unsigned idx = PHI_ARG_INDEX_FROM_USE (use_p); |
1226 | edge e = gimple_phi_arg_edge (use_phi, idx); | |
c77fae1c RB |
1227 | /* Do not look for uses in the next iteration of a loop, predicate |
1228 | analysis will not use the appropriate predicates to prove | |
1229 | reachability. */ | |
1230 | if (e->flags & EDGE_DFS_BACK) | |
1231 | continue; | |
5e48d8a0 | 1232 | |
8a63343a RB |
1233 | basic_block use_bb = e->src; |
1234 | if (def_preds.is_use_guarded (use_stmt, use_bb, phi, uninit_opnds)) | |
4a8f98fa | 1235 | { |
8a63343a RB |
1236 | /* For a guarded use in a PHI record the PHI argument as |
1237 | initialized. */ | |
4a8f98fa RB |
1238 | if (idx < uninit_analysis::func_t::max_phi_args) |
1239 | { | |
1240 | bool existed_p; | |
1241 | auto &def_mask | |
8a63343a | 1242 | = defined_args->get_or_insert (use_phi, &existed_p); |
4a8f98fa RB |
1243 | if (!existed_p) |
1244 | def_mask = 0; | |
1245 | MASK_SET_BIT (def_mask, idx); | |
1246 | } | |
8a63343a | 1247 | continue; |
4a8f98fa | 1248 | } |
8a63343a RB |
1249 | |
1250 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1251 | { | |
1252 | fprintf (dump_file, "Found unguarded use in bb %u: ", | |
1253 | use_bb->index); | |
1254 | print_gimple_stmt (dump_file, use_stmt, 0); | |
1255 | } | |
1256 | /* Found a phi use that is not guarded, mark the phi_result as | |
1257 | possibly undefined. */ | |
1258 | possibly_undefined_names->add (phi_result); | |
4a8f98fa | 1259 | } |
8a63343a RB |
1260 | else |
1261 | cands.safe_push (use_stmt); | |
1262 | } | |
1263 | ||
1264 | /* Sort candidates after RPO. */ | |
1265 | cands.stablesort (cand_cmp, bb_to_rpo); | |
1266 | basic_block use_bb = NULL; | |
1267 | for (gimple *use_stmt : cands) | |
1268 | { | |
1269 | /* We only have to try diagnosing the first use in each block. */ | |
1270 | if (gimple_bb (use_stmt) == use_bb) | |
1271 | continue; | |
1272 | ||
1273 | use_bb = gimple_bb (use_stmt); | |
1274 | if (def_preds.is_use_guarded (use_stmt, use_bb, phi, uninit_opnds)) | |
1275 | continue; | |
34f97b94 | 1276 | |
94c12ffa MS |
1277 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1278 | { | |
1279 | fprintf (dump_file, "Found unguarded use in bb %u: ", | |
1280 | use_bb->index); | |
1281 | print_gimple_stmt (dump_file, use_stmt, 0); | |
5e48d8a0 | 1282 | } |
8a63343a | 1283 | return use_stmt; |
34f97b94 XDL |
1284 | } |
1285 | ||
8a63343a | 1286 | return NULL; |
34f97b94 XDL |
1287 | } |
1288 | ||
94c12ffa MS |
1289 | /* Look for inputs to PHI that are SSA_NAMEs that have empty definitions |
1290 | and gives warning if there exists a runtime path from the entry to a | |
1291 | use of the PHI def that does not contain a definition. In other words, | |
1292 | the warning is on the real use. The more dead paths that can be pruned | |
4a8f98fa | 1293 | by the compiler, the fewer false positives the warning is. */ |
34f97b94 XDL |
1294 | |
1295 | static void | |
8a63343a | 1296 | warn_uninitialized_phi (gphi *phi, unsigned uninit_opnds, int *bb_to_rpo) |
34f97b94 | 1297 | { |
94c12ffa | 1298 | if (dump_file && (dump_flags & TDF_DETAILS)) |
34f97b94 | 1299 | { |
94c12ffa MS |
1300 | fprintf (dump_file, "Examining phi: "); |
1301 | print_gimple_stmt (dump_file, phi, 0); | |
34f97b94 | 1302 | } |
34f97b94 | 1303 | |
8a63343a | 1304 | gimple *uninit_use_stmt = find_uninit_use (phi, uninit_opnds, bb_to_rpo); |
34f97b94 | 1305 | |
4a8f98fa | 1306 | /* All uses are properly guarded. */ |
94c12ffa MS |
1307 | if (!uninit_use_stmt) |
1308 | return; | |
34f97b94 | 1309 | |
94c12ffa MS |
1310 | unsigned phiarg_index = MASK_FIRST_SET_BIT (uninit_opnds); |
1311 | tree uninit_op = gimple_phi_arg_def (phi, phiarg_index); | |
1312 | if (SSA_NAME_VAR (uninit_op) == NULL_TREE) | |
1313 | return; | |
34f97b94 | 1314 | |
94c12ffa MS |
1315 | location_t loc = UNKNOWN_LOCATION; |
1316 | if (gimple_phi_arg_has_location (phi, phiarg_index)) | |
1317 | loc = gimple_phi_arg_location (phi, phiarg_index); | |
1318 | else | |
34f97b94 | 1319 | { |
94c12ffa MS |
1320 | tree arg_def = gimple_phi_arg_def (phi, phiarg_index); |
1321 | if (TREE_CODE (arg_def) == SSA_NAME) | |
5e48d8a0 | 1322 | { |
94c12ffa MS |
1323 | gimple *def_stmt = SSA_NAME_DEF_STMT (arg_def); |
1324 | if (gphi *arg_phi = dyn_cast<gphi *> (def_stmt)) | |
1325 | { | |
1326 | unsigned uop = compute_uninit_opnds_pos (arg_phi); | |
1327 | unsigned idx = MASK_FIRST_SET_BIT (uop); | |
1328 | if (idx < gimple_phi_num_args (arg_phi) | |
1329 | && gimple_phi_arg_has_location (arg_phi, idx)) | |
1330 | loc = gimple_phi_arg_location (arg_phi, idx); | |
1331 | } | |
5e48d8a0 | 1332 | } |
34f97b94 XDL |
1333 | } |
1334 | ||
94c12ffa MS |
1335 | warn_uninit (OPT_Wmaybe_uninitialized, uninit_op, |
1336 | SSA_NAME_VAR (uninit_op), | |
94c12ffa | 1337 | uninit_use_stmt, loc); |
34f97b94 XDL |
1338 | } |
1339 | ||
94c12ffa MS |
1340 | static bool |
1341 | gate_warn_uninitialized (void) | |
11ef0b22 | 1342 | { |
94c12ffa | 1343 | return warn_uninitialized || warn_maybe_uninitialized; |
11ef0b22 AH |
1344 | } |
1345 | ||
94c12ffa | 1346 | namespace { |
11ef0b22 | 1347 | |
94c12ffa | 1348 | const pass_data pass_data_late_warn_uninitialized = |
11ef0b22 | 1349 | { |
94c12ffa MS |
1350 | GIMPLE_PASS, /* type */ |
1351 | "uninit", /* name */ | |
1352 | OPTGROUP_NONE, /* optinfo_flags */ | |
1353 | TV_NONE, /* tv_id */ | |
1354 | PROP_ssa, /* properties_required */ | |
1355 | 0, /* properties_provided */ | |
1356 | 0, /* properties_destroyed */ | |
1357 | 0, /* todo_flags_start */ | |
1358 | 0, /* todo_flags_finish */ | |
1359 | }; | |
34f97b94 | 1360 | |
94c12ffa | 1361 | class pass_late_warn_uninitialized : public gimple_opt_pass |
34f97b94 | 1362 | { |
94c12ffa MS |
1363 | public: |
1364 | pass_late_warn_uninitialized (gcc::context *ctxt) | |
1365 | : gimple_opt_pass (pass_data_late_warn_uninitialized, ctxt) | |
1366 | {} | |
1367 | ||
1368 | /* opt_pass methods: */ | |
725793af DM |
1369 | opt_pass *clone () final override |
1370 | { | |
1371 | return new pass_late_warn_uninitialized (m_ctxt); | |
1372 | } | |
1373 | bool gate (function *) final override { return gate_warn_uninitialized (); } | |
1374 | unsigned int execute (function *) final override; | |
34f97b94 | 1375 | |
94c12ffa | 1376 | }; // class pass_late_warn_uninitialized |
34f97b94 XDL |
1377 | |
1378 | static void | |
94c12ffa | 1379 | execute_late_warn_uninitialized (function *fun) |
34f97b94 | 1380 | { |
94c12ffa MS |
1381 | calculate_dominance_info (CDI_DOMINATORS); |
1382 | calculate_dominance_info (CDI_POST_DOMINATORS); | |
0f58ba4d RB |
1383 | |
1384 | /* Mark all edges executable, warn_uninitialized_vars will skip | |
1385 | unreachable blocks. */ | |
1386 | set_all_edges_as_executable (fun); | |
c77fae1c | 1387 | mark_dfs_back_edges (fun); |
4a8f98fa RB |
1388 | int *rpo = XNEWVEC (int, n_basic_blocks_for_fn (fun)); |
1389 | int n = pre_and_rev_post_order_compute_fn (fun, NULL, rpo, false); | |
8a63343a RB |
1390 | int *bb_to_rpo = XNEWVEC (int, last_basic_block_for_fn (fun)); |
1391 | for (int i = 0; i < n; ++i) | |
1392 | bb_to_rpo[rpo[i]] = i; | |
0f58ba4d | 1393 | |
94c12ffa MS |
1394 | /* Re-do the plain uninitialized variable check, as optimization may have |
1395 | straightened control flow. Do this first so that we don't accidentally | |
1396 | get a "may be" warning when we'd have seen an "is" warning later. */ | |
1397 | warn_uninitialized_vars (/*warn_maybe_uninitialized=*/1); | |
34f97b94 | 1398 | |
94c12ffa | 1399 | timevar_push (TV_TREE_UNINIT); |
34f97b94 | 1400 | |
17844729 RB |
1401 | /* Avoid quadratic beahvior when looking up case labels for edges. */ |
1402 | start_recording_case_labels (); | |
1403 | ||
94c12ffa | 1404 | possibly_undefined_names = new hash_set<tree>; |
4a8f98fa RB |
1405 | defined_args = new hash_map<gphi *, uninit_analysis::func_t::phi_arg_set_t>; |
1406 | ||
1407 | /* Walk the CFG in RPO order so we visit PHIs with defs that are | |
1408 | possibly uninitialized from other PHIs after those. The uninit | |
1409 | predicate analysis will then expand the PHIs predicate with | |
1410 | the predicates of the edges from such PHI defs. */ | |
1411 | for (int i = 0; i < n; ++i) | |
1412 | for (auto gsi = gsi_start_phis (BASIC_BLOCK_FOR_FN (fun, rpo[i])); | |
1413 | !gsi_end_p (gsi); gsi_next (&gsi)) | |
94c12ffa MS |
1414 | { |
1415 | gphi *phi = gsi.phi (); | |
be55bfe6 TS |
1416 | |
1417 | /* Don't look at virtual operands. */ | |
1418 | if (virtual_operand_p (gimple_phi_result (phi))) | |
1419 | continue; | |
1420 | ||
4a8f98fa RB |
1421 | unsigned uninit_opnds = compute_uninit_opnds_pos (phi); |
1422 | if (MASK_EMPTY (uninit_opnds)) | |
1423 | continue; | |
34f97b94 | 1424 | |
8a63343a | 1425 | warn_uninitialized_phi (phi, uninit_opnds, bb_to_rpo); |
4a8f98fa | 1426 | } |
e74780a3 | 1427 | |
4a8f98fa | 1428 | free (rpo); |
8a63343a | 1429 | free (bb_to_rpo); |
6e2830c3 | 1430 | delete possibly_undefined_names; |
34f97b94 | 1431 | possibly_undefined_names = NULL; |
4a8f98fa RB |
1432 | delete defined_args; |
1433 | defined_args = NULL; | |
17844729 | 1434 | end_recording_case_labels (); |
34f97b94 XDL |
1435 | free_dominance_info (CDI_POST_DOMINATORS); |
1436 | timevar_pop (TV_TREE_UNINIT); | |
94c12ffa MS |
1437 | } |
1438 | ||
1439 | unsigned int | |
1440 | pass_late_warn_uninitialized::execute (function *fun) | |
1441 | { | |
1442 | execute_late_warn_uninitialized (fun); | |
34f97b94 XDL |
1443 | return 0; |
1444 | } | |
1445 | ||
27a4cd48 DM |
1446 | } // anon namespace |
1447 | ||
1448 | gimple_opt_pass * | |
1449 | make_pass_late_warn_uninitialized (gcc::context *ctxt) | |
1450 | { | |
1451 | return new pass_late_warn_uninitialized (ctxt); | |
1452 | } | |
c152901f | 1453 | |
c152901f | 1454 | static unsigned int |
0f58ba4d | 1455 | execute_early_warn_uninitialized (struct function *fun) |
c152901f AM |
1456 | { |
1457 | /* Currently, this pass runs always but | |
ac0e4fde | 1458 | execute_late_warn_uninitialized only runs with optimization. With |
c152901f AM |
1459 | optimization we want to warn about possible uninitialized as late |
1460 | as possible, thus don't do it here. However, without | |
927734cf | 1461 | optimization we need to warn here about "may be uninitialized". */ |
66030d68 | 1462 | calculate_dominance_info (CDI_DOMINATORS); |
c152901f AM |
1463 | calculate_dominance_info (CDI_POST_DOMINATORS); |
1464 | ||
0f58ba4d RB |
1465 | /* Use VN in its cheapest incarnation and without doing any |
1466 | elimination to compute edge reachability. Don't bother when | |
1467 | we only warn for unconditionally executed code though. */ | |
1468 | if (!optimize) | |
805c9184 | 1469 | do_rpo_vn (fun, NULL, NULL, false, false, VN_NOWALK); |
0f58ba4d RB |
1470 | else |
1471 | set_all_edges_as_executable (fun); | |
1472 | ||
b825a228 | 1473 | warn_uninitialized_vars (/*warn_maybe_uninitialized=*/!optimize); |
c152901f | 1474 | |
67914693 | 1475 | /* Post-dominator information cannot be reliably updated. Free it |
c152901f AM |
1476 | after the use. */ |
1477 | ||
1478 | free_dominance_info (CDI_POST_DOMINATORS); | |
1479 | return 0; | |
1480 | } | |
1481 | ||
c152901f AM |
1482 | namespace { |
1483 | ||
1484 | const pass_data pass_data_early_warn_uninitialized = | |
1485 | { | |
1486 | GIMPLE_PASS, /* type */ | |
0f58ba4d | 1487 | "early_uninit", /* name */ |
c152901f | 1488 | OPTGROUP_NONE, /* optinfo_flags */ |
c152901f AM |
1489 | TV_TREE_UNINIT, /* tv_id */ |
1490 | PROP_ssa, /* properties_required */ | |
1491 | 0, /* properties_provided */ | |
1492 | 0, /* properties_destroyed */ | |
1493 | 0, /* todo_flags_start */ | |
1494 | 0, /* todo_flags_finish */ | |
1495 | }; | |
1496 | ||
1497 | class pass_early_warn_uninitialized : public gimple_opt_pass | |
1498 | { | |
1499 | public: | |
c3284718 RS |
1500 | pass_early_warn_uninitialized (gcc::context *ctxt) |
1501 | : gimple_opt_pass (pass_data_early_warn_uninitialized, ctxt) | |
c152901f AM |
1502 | {} |
1503 | ||
1504 | /* opt_pass methods: */ | |
725793af DM |
1505 | bool gate (function *) final override { return gate_warn_uninitialized (); } |
1506 | unsigned int execute (function *fun) final override | |
ac0e4fde | 1507 | { |
0f58ba4d | 1508 | return execute_early_warn_uninitialized (fun); |
ac0e4fde | 1509 | } |
c152901f AM |
1510 | |
1511 | }; // class pass_early_warn_uninitialized | |
1512 | ||
1513 | } // anon namespace | |
1514 | ||
1515 | gimple_opt_pass * | |
1516 | make_pass_early_warn_uninitialized (gcc::context *ctxt) | |
1517 | { | |
1518 | return new pass_early_warn_uninitialized (ctxt); | |
1519 | } |