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10a0d495 | 1 | /* __builtin_object_size (ptr, object_size_type) computation |
8d9254fc | 2 | Copyright (C) 2004-2020 Free Software Foundation, Inc. |
10a0d495 JJ |
3 | Contributed by Jakub Jelinek <jakub@redhat.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 | |
9dcd6f09 | 9 | the Free Software Foundation; either version 3, or (at your option) |
10a0d495 JJ |
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 | |
9dcd6f09 NC |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
10a0d495 JJ |
20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
c7131fb2 | 24 | #include "backend.h" |
10a0d495 | 25 | #include "tree.h" |
c7131fb2 | 26 | #include "gimple.h" |
957060b5 | 27 | #include "tree-pass.h" |
c7131fb2 | 28 | #include "ssa.h" |
957060b5 | 29 | #include "gimple-pretty-print.h" |
40e23961 | 30 | #include "fold-const.h" |
d8a2d370 | 31 | #include "tree-object-size.h" |
2fb9a547 | 32 | #include "gimple-fold.h" |
5be5c238 | 33 | #include "gimple-iterator.h" |
1e080ab4 | 34 | #include "tree-cfg.h" |
314e6352 ML |
35 | #include "stringpool.h" |
36 | #include "attribs.h" | |
10a0d495 JJ |
37 | |
38 | struct object_size_info | |
39 | { | |
40 | int object_size_type; | |
34e82342 | 41 | unsigned char pass; |
10a0d495 | 42 | bool changed; |
34e82342 | 43 | bitmap visited, reexamine; |
10a0d495 JJ |
44 | unsigned int *depths; |
45 | unsigned int *stack, *tos; | |
46 | }; | |
47 | ||
a43068cc JJ |
48 | static const unsigned HOST_WIDE_INT unknown[4] = { |
49 | HOST_WIDE_INT_M1U, | |
50 | HOST_WIDE_INT_M1U, | |
51 | 0, | |
52 | 0 | |
53 | }; | |
10a0d495 | 54 | |
ac545c64 | 55 | static tree compute_object_offset (const_tree, const_tree); |
05a64756 | 56 | static bool addr_object_size (struct object_size_info *, |
28a5fa54 | 57 | const_tree, int, unsigned HOST_WIDE_INT *, |
f7d86b5c | 58 | tree * = NULL, tree * = NULL); |
538dd0b7 DM |
59 | static unsigned HOST_WIDE_INT alloc_object_size (const gcall *, int); |
60 | static tree pass_through_call (const gcall *); | |
10a0d495 JJ |
61 | static void collect_object_sizes_for (struct object_size_info *, tree); |
62 | static void expr_object_size (struct object_size_info *, tree, tree); | |
63 | static bool merge_object_sizes (struct object_size_info *, tree, tree, | |
64 | unsigned HOST_WIDE_INT); | |
60dd79ca TS |
65 | static bool plus_stmt_object_size (struct object_size_info *, tree, gimple *); |
66 | static bool cond_expr_object_size (struct object_size_info *, tree, gimple *); | |
10a0d495 JJ |
67 | static void init_offset_limit (void); |
68 | static void check_for_plus_in_loops (struct object_size_info *, tree); | |
69 | static void check_for_plus_in_loops_1 (struct object_size_info *, tree, | |
70 | unsigned int); | |
71 | ||
72 | /* object_sizes[0] is upper bound for number of bytes till the end of | |
73 | the object. | |
74 | object_sizes[1] is upper bound for number of bytes till the end of | |
75 | the subobject (innermost array or field with address taken). | |
76 | object_sizes[2] is lower bound for number of bytes till the end of | |
77 | the object and object_sizes[3] lower bound for subobject. */ | |
db84d11e | 78 | static vec<unsigned HOST_WIDE_INT> object_sizes[4]; |
10a0d495 JJ |
79 | |
80 | /* Bitmaps what object sizes have been computed already. */ | |
81 | static bitmap computed[4]; | |
82 | ||
83 | /* Maximum value of offset we consider to be addition. */ | |
84 | static unsigned HOST_WIDE_INT offset_limit; | |
85 | ||
86 | ||
87 | /* Initialize OFFSET_LIMIT variable. */ | |
88 | static void | |
89 | init_offset_limit (void) | |
90 | { | |
cc269bb6 | 91 | if (tree_fits_uhwi_p (TYPE_MAX_VALUE (sizetype))) |
ae7e9ddd | 92 | offset_limit = tree_to_uhwi (TYPE_MAX_VALUE (sizetype)); |
10a0d495 JJ |
93 | else |
94 | offset_limit = -1; | |
95 | offset_limit /= 2; | |
96 | } | |
97 | ||
98 | ||
99 | /* Compute offset of EXPR within VAR. Return error_mark_node | |
100 | if unknown. */ | |
101 | ||
102 | static tree | |
ac545c64 | 103 | compute_object_offset (const_tree expr, const_tree var) |
10a0d495 JJ |
104 | { |
105 | enum tree_code code = PLUS_EXPR; | |
106 | tree base, off, t; | |
107 | ||
108 | if (expr == var) | |
109 | return size_zero_node; | |
110 | ||
111 | switch (TREE_CODE (expr)) | |
112 | { | |
113 | case COMPONENT_REF: | |
114 | base = compute_object_offset (TREE_OPERAND (expr, 0), var); | |
115 | if (base == error_mark_node) | |
116 | return base; | |
117 | ||
118 | t = TREE_OPERAND (expr, 1); | |
119 | off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t), | |
ae7e9ddd | 120 | size_int (tree_to_uhwi (DECL_FIELD_BIT_OFFSET (t)) |
10a0d495 JJ |
121 | / BITS_PER_UNIT)); |
122 | break; | |
123 | ||
124 | case REALPART_EXPR: | |
1043771b | 125 | CASE_CONVERT: |
10a0d495 JJ |
126 | case VIEW_CONVERT_EXPR: |
127 | case NON_LVALUE_EXPR: | |
128 | return compute_object_offset (TREE_OPERAND (expr, 0), var); | |
129 | ||
130 | case IMAGPART_EXPR: | |
131 | base = compute_object_offset (TREE_OPERAND (expr, 0), var); | |
132 | if (base == error_mark_node) | |
133 | return base; | |
134 | ||
135 | off = TYPE_SIZE_UNIT (TREE_TYPE (expr)); | |
136 | break; | |
137 | ||
138 | case ARRAY_REF: | |
139 | base = compute_object_offset (TREE_OPERAND (expr, 0), var); | |
140 | if (base == error_mark_node) | |
141 | return base; | |
142 | ||
143 | t = TREE_OPERAND (expr, 1); | |
2d4102c5 JJ |
144 | tree low_bound, unit_size; |
145 | low_bound = array_ref_low_bound (CONST_CAST_TREE (expr)); | |
146 | unit_size = array_ref_element_size (CONST_CAST_TREE (expr)); | |
147 | if (! integer_zerop (low_bound)) | |
148 | t = fold_build2 (MINUS_EXPR, TREE_TYPE (t), t, low_bound); | |
10a0d495 JJ |
149 | if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0) |
150 | { | |
151 | code = MINUS_EXPR; | |
152 | t = fold_build1 (NEGATE_EXPR, TREE_TYPE (t), t); | |
153 | } | |
b6f65e3c | 154 | t = fold_convert (sizetype, t); |
2d4102c5 | 155 | off = size_binop (MULT_EXPR, unit_size, t); |
10a0d495 JJ |
156 | break; |
157 | ||
70f34814 RG |
158 | case MEM_REF: |
159 | gcc_assert (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR); | |
807e902e | 160 | return wide_int_to_tree (sizetype, mem_ref_offset (expr)); |
70f34814 | 161 | |
10a0d495 JJ |
162 | default: |
163 | return error_mark_node; | |
164 | } | |
165 | ||
166 | return size_binop (code, base, off); | |
167 | } | |
168 | ||
7a41fcde MS |
169 | /* Returns the size of the object designated by DECL considering its |
170 | initializer if it either has one or if it would not affect its size, | |
171 | otherwise the size of the object without the initializer when MIN | |
172 | is true, else null. An object's initializer affects the object's | |
173 | size if it's a struct type with a flexible array member. */ | |
174 | ||
a2c2cee9 | 175 | tree |
7a41fcde MS |
176 | decl_init_size (tree decl, bool min) |
177 | { | |
178 | tree size = DECL_SIZE_UNIT (decl); | |
179 | tree type = TREE_TYPE (decl); | |
180 | if (TREE_CODE (type) != RECORD_TYPE) | |
181 | return size; | |
182 | ||
183 | tree last = last_field (type); | |
184 | if (!last) | |
185 | return size; | |
186 | ||
187 | tree last_type = TREE_TYPE (last); | |
188 | if (TREE_CODE (last_type) != ARRAY_TYPE | |
189 | || TYPE_SIZE (last_type)) | |
190 | return size; | |
191 | ||
192 | /* Use TYPE_SIZE_UNIT; DECL_SIZE_UNIT sometimes reflects the size | |
193 | of the initializer and sometimes doesn't. */ | |
194 | size = TYPE_SIZE_UNIT (type); | |
195 | tree ref = build3 (COMPONENT_REF, type, decl, last, NULL_TREE); | |
196 | tree compsize = component_ref_size (ref); | |
197 | if (!compsize) | |
198 | return min ? size : NULL_TREE; | |
199 | ||
200 | /* The size includes tail padding and initializer elements. */ | |
201 | tree pos = byte_position (last); | |
202 | size = fold_build2 (PLUS_EXPR, TREE_TYPE (size), pos, compsize); | |
203 | return size; | |
204 | } | |
10a0d495 JJ |
205 | |
206 | /* Compute __builtin_object_size for PTR, which is a ADDR_EXPR. | |
207 | OBJECT_SIZE_TYPE is the second argument from __builtin_object_size. | |
208 | If unknown, return unknown[object_size_type]. */ | |
209 | ||
05a64756 | 210 | static bool |
eb9ed98a | 211 | addr_object_size (struct object_size_info *osi, const_tree ptr, |
28a5fa54 | 212 | int object_size_type, unsigned HOST_WIDE_INT *psize, |
f7d86b5c | 213 | tree *pdecl /* = NULL */, tree *poff /* = NULL */) |
10a0d495 | 214 | { |
eb9ed98a | 215 | tree pt_var, pt_var_size = NULL_TREE, var_size, bytes; |
10a0d495 | 216 | |
f7d86b5c | 217 | tree dummy_decl, dummy_off = size_zero_node; |
28a5fa54 | 218 | if (!pdecl) |
f7d86b5c MS |
219 | pdecl = &dummy_decl; |
220 | if (!poff) | |
221 | poff = &dummy_off; | |
28a5fa54 | 222 | |
10a0d495 JJ |
223 | gcc_assert (TREE_CODE (ptr) == ADDR_EXPR); |
224 | ||
05a64756 MS |
225 | /* Set to unknown and overwrite just before returning if the size |
226 | could be determined. */ | |
227 | *psize = unknown[object_size_type]; | |
228 | ||
10a0d495 | 229 | pt_var = TREE_OPERAND (ptr, 0); |
d837d73d RG |
230 | while (handled_component_p (pt_var)) |
231 | pt_var = TREE_OPERAND (pt_var, 0); | |
10a0d495 | 232 | |
7a41fcde MS |
233 | if (!pt_var) |
234 | return false; | |
235 | ||
236 | if (TREE_CODE (pt_var) == MEM_REF) | |
10a0d495 | 237 | { |
eb9ed98a | 238 | unsigned HOST_WIDE_INT sz; |
10a0d495 | 239 | |
d837d73d | 240 | if (!osi || (object_size_type & 1) != 0 |
ea17de23 | 241 | || TREE_CODE (TREE_OPERAND (pt_var, 0)) != SSA_NAME) |
70f34814 | 242 | { |
05a64756 | 243 | compute_builtin_object_size (TREE_OPERAND (pt_var, 0), |
f7d86b5c | 244 | object_size_type & ~1, &sz, pdecl, poff); |
70f34814 | 245 | } |
eb9ed98a | 246 | else |
10a0d495 | 247 | { |
eb9ed98a JJ |
248 | tree var = TREE_OPERAND (pt_var, 0); |
249 | if (osi->pass == 0) | |
250 | collect_object_sizes_for (osi, var); | |
251 | if (bitmap_bit_p (computed[object_size_type], | |
252 | SSA_NAME_VERSION (var))) | |
253 | sz = object_sizes[object_size_type][SSA_NAME_VERSION (var)]; | |
254 | else | |
255 | sz = unknown[object_size_type]; | |
d837d73d RG |
256 | } |
257 | if (sz != unknown[object_size_type]) | |
258 | { | |
aca52e6f RS |
259 | offset_int mem_offset; |
260 | if (mem_ref_offset (pt_var).is_constant (&mem_offset)) | |
261 | { | |
a2c2cee9 MS |
262 | if (*poff) |
263 | *poff = wide_int_to_tree (ptrdiff_type_node, | |
264 | mem_offset + wi::to_offset (*poff)); | |
265 | else | |
266 | *poff = wide_int_to_tree (ptrdiff_type_node, mem_offset); | |
aca52e6f RS |
267 | offset_int dsz = wi::sub (sz, mem_offset); |
268 | if (wi::neg_p (dsz)) | |
269 | sz = 0; | |
270 | else if (wi::fits_uhwi_p (dsz)) | |
271 | sz = dsz.to_uhwi (); | |
272 | else | |
273 | sz = unknown[object_size_type]; | |
274 | } | |
70f34814 | 275 | else |
d837d73d | 276 | sz = unknown[object_size_type]; |
eb9ed98a JJ |
277 | } |
278 | ||
279 | if (sz != unknown[object_size_type] && sz < offset_limit) | |
280 | pt_var_size = size_int (sz); | |
281 | } | |
7a41fcde | 282 | else if (DECL_P (pt_var)) |
28a5fa54 MS |
283 | { |
284 | *pdecl = pt_var; | |
7a41fcde MS |
285 | pt_var_size = decl_init_size (pt_var, object_size_type & 2); |
286 | if (!pt_var_size) | |
287 | return false; | |
28a5fa54 | 288 | } |
7a41fcde | 289 | else if (TREE_CODE (pt_var) == STRING_CST) |
eb9ed98a JJ |
290 | pt_var_size = TYPE_SIZE_UNIT (TREE_TYPE (pt_var)); |
291 | else | |
05a64756 | 292 | return false; |
eb9ed98a | 293 | |
7a41fcde MS |
294 | if (pt_var_size) |
295 | { | |
296 | /* Validate the size determined above. */ | |
297 | if (!tree_fits_uhwi_p (pt_var_size) | |
298 | || tree_to_uhwi (pt_var_size) >= offset_limit) | |
299 | return false; | |
300 | } | |
301 | ||
eb9ed98a JJ |
302 | if (pt_var != TREE_OPERAND (ptr, 0)) |
303 | { | |
304 | tree var; | |
10a0d495 | 305 | |
eb9ed98a JJ |
306 | if (object_size_type & 1) |
307 | { | |
308 | var = TREE_OPERAND (ptr, 0); | |
309 | ||
310 | while (var != pt_var | |
311 | && TREE_CODE (var) != BIT_FIELD_REF | |
312 | && TREE_CODE (var) != COMPONENT_REF | |
313 | && TREE_CODE (var) != ARRAY_REF | |
314 | && TREE_CODE (var) != ARRAY_RANGE_REF | |
315 | && TREE_CODE (var) != REALPART_EXPR | |
316 | && TREE_CODE (var) != IMAGPART_EXPR) | |
317 | var = TREE_OPERAND (var, 0); | |
318 | if (var != pt_var && TREE_CODE (var) == ARRAY_REF) | |
38027156 | 319 | var = TREE_OPERAND (var, 0); |
eb9ed98a | 320 | if (! TYPE_SIZE_UNIT (TREE_TYPE (var)) |
cc269bb6 | 321 | || ! tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (var))) |
eb9ed98a JJ |
322 | || (pt_var_size |
323 | && tree_int_cst_lt (pt_var_size, | |
324 | TYPE_SIZE_UNIT (TREE_TYPE (var))))) | |
325 | var = pt_var; | |
70f34814 | 326 | else if (var != pt_var && TREE_CODE (pt_var) == MEM_REF) |
10a0d495 | 327 | { |
eb9ed98a JJ |
328 | tree v = var; |
329 | /* For &X->fld, compute object size only if fld isn't the last | |
330 | field, as struct { int i; char c[1]; } is often used instead | |
331 | of flexible array member. */ | |
332 | while (v && v != pt_var) | |
333 | switch (TREE_CODE (v)) | |
334 | { | |
335 | case ARRAY_REF: | |
336 | if (TYPE_SIZE_UNIT (TREE_TYPE (TREE_OPERAND (v, 0))) | |
337 | && TREE_CODE (TREE_OPERAND (v, 1)) == INTEGER_CST) | |
338 | { | |
339 | tree domain | |
340 | = TYPE_DOMAIN (TREE_TYPE (TREE_OPERAND (v, 0))); | |
341 | if (domain | |
342 | && TYPE_MAX_VALUE (domain) | |
343 | && TREE_CODE (TYPE_MAX_VALUE (domain)) | |
344 | == INTEGER_CST | |
345 | && tree_int_cst_lt (TREE_OPERAND (v, 1), | |
346 | TYPE_MAX_VALUE (domain))) | |
347 | { | |
348 | v = NULL_TREE; | |
349 | break; | |
350 | } | |
351 | } | |
352 | v = TREE_OPERAND (v, 0); | |
353 | break; | |
354 | case REALPART_EXPR: | |
355 | case IMAGPART_EXPR: | |
356 | v = NULL_TREE; | |
357 | break; | |
358 | case COMPONENT_REF: | |
8593e0b6 JJ |
359 | if (TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE) |
360 | { | |
361 | v = NULL_TREE; | |
362 | break; | |
363 | } | |
38027156 JJ |
364 | while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) |
365 | if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
366 | != UNION_TYPE | |
367 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
368 | != QUAL_UNION_TYPE) | |
369 | break; | |
370 | else | |
371 | v = TREE_OPERAND (v, 0); | |
372 | if (TREE_CODE (v) == COMPONENT_REF | |
373 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
374 | == RECORD_TYPE) | |
eb9ed98a | 375 | { |
910ad8de NF |
376 | tree fld_chain = DECL_CHAIN (TREE_OPERAND (v, 1)); |
377 | for (; fld_chain; fld_chain = DECL_CHAIN (fld_chain)) | |
8593e0b6 JJ |
378 | if (TREE_CODE (fld_chain) == FIELD_DECL) |
379 | break; | |
380 | ||
381 | if (fld_chain) | |
382 | { | |
383 | v = NULL_TREE; | |
eb9ed98a | 384 | break; |
8593e0b6 | 385 | } |
38027156 | 386 | v = TREE_OPERAND (v, 0); |
eb9ed98a | 387 | } |
38027156 JJ |
388 | while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) |
389 | if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
390 | != UNION_TYPE | |
391 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
392 | != QUAL_UNION_TYPE) | |
8593e0b6 JJ |
393 | break; |
394 | else | |
395 | v = TREE_OPERAND (v, 0); | |
38027156 | 396 | if (v != pt_var) |
8593e0b6 JJ |
397 | v = NULL_TREE; |
398 | else | |
399 | v = pt_var; | |
eb9ed98a JJ |
400 | break; |
401 | default: | |
402 | v = pt_var; | |
403 | break; | |
404 | } | |
405 | if (v == pt_var) | |
10a0d495 JJ |
406 | var = pt_var; |
407 | } | |
eb9ed98a JJ |
408 | } |
409 | else | |
410 | var = pt_var; | |
10a0d495 | 411 | |
eb9ed98a JJ |
412 | if (var != pt_var) |
413 | var_size = TYPE_SIZE_UNIT (TREE_TYPE (var)); | |
414 | else if (!pt_var_size) | |
05a64756 | 415 | return false; |
eb9ed98a JJ |
416 | else |
417 | var_size = pt_var_size; | |
418 | bytes = compute_object_offset (TREE_OPERAND (ptr, 0), var); | |
419 | if (bytes != error_mark_node) | |
420 | { | |
a2c2cee9 | 421 | *poff = bytes; |
eb9ed98a JJ |
422 | if (TREE_CODE (bytes) == INTEGER_CST |
423 | && tree_int_cst_lt (var_size, bytes)) | |
424 | bytes = size_zero_node; | |
425 | else | |
426 | bytes = size_binop (MINUS_EXPR, var_size, bytes); | |
427 | } | |
428 | if (var != pt_var | |
429 | && pt_var_size | |
70f34814 | 430 | && TREE_CODE (pt_var) == MEM_REF |
eb9ed98a JJ |
431 | && bytes != error_mark_node) |
432 | { | |
433 | tree bytes2 = compute_object_offset (TREE_OPERAND (ptr, 0), pt_var); | |
434 | if (bytes2 != error_mark_node) | |
10a0d495 | 435 | { |
eb9ed98a JJ |
436 | if (TREE_CODE (bytes2) == INTEGER_CST |
437 | && tree_int_cst_lt (pt_var_size, bytes2)) | |
438 | bytes2 = size_zero_node; | |
10a0d495 | 439 | else |
98a129b9 | 440 | bytes2 = size_binop (MINUS_EXPR, pt_var_size, bytes2); |
f7d86b5c | 441 | *poff = size_binop (PLUS_EXPR, *poff, bytes2); |
eb9ed98a | 442 | bytes = size_binop (MIN_EXPR, bytes, bytes2); |
10a0d495 JJ |
443 | } |
444 | } | |
10a0d495 | 445 | } |
eb9ed98a | 446 | else if (!pt_var_size) |
05a64756 | 447 | return false; |
eb9ed98a | 448 | else |
a2c2cee9 MS |
449 | { |
450 | bytes = pt_var_size; | |
451 | if (!*poff) | |
452 | *poff = size_zero_node; | |
453 | } | |
eb9ed98a | 454 | |
cc269bb6 | 455 | if (tree_fits_uhwi_p (bytes)) |
05a64756 MS |
456 | { |
457 | *psize = tree_to_uhwi (bytes); | |
458 | return true; | |
459 | } | |
10a0d495 | 460 | |
05a64756 | 461 | return false; |
10a0d495 JJ |
462 | } |
463 | ||
464 | ||
726a989a | 465 | /* Compute __builtin_object_size for CALL, which is a GIMPLE_CALL. |
302db8ba MS |
466 | Handles calls to functions declared with attribute alloc_size. |
467 | OBJECT_SIZE_TYPE is the second argument from __builtin_object_size. | |
468 | If unknown, return unknown[object_size_type]. */ | |
10a0d495 JJ |
469 | |
470 | static unsigned HOST_WIDE_INT | |
538dd0b7 | 471 | alloc_object_size (const gcall *call, int object_size_type) |
10a0d495 | 472 | { |
726a989a | 473 | gcc_assert (is_gimple_call (call)); |
10a0d495 | 474 | |
302db8ba MS |
475 | tree calltype; |
476 | if (tree callfn = gimple_call_fndecl (call)) | |
477 | calltype = TREE_TYPE (callfn); | |
478 | else | |
479 | calltype = gimple_call_fntype (call); | |
480 | ||
481 | if (!calltype) | |
51bc54a6 DM |
482 | return unknown[object_size_type]; |
483 | ||
302db8ba MS |
484 | /* Set to positions of alloc_size arguments. */ |
485 | int arg1 = -1, arg2 = -1; | |
486 | tree alloc_size = lookup_attribute ("alloc_size", | |
487 | TYPE_ATTRIBUTES (calltype)); | |
51bc54a6 DM |
488 | if (alloc_size && TREE_VALUE (alloc_size)) |
489 | { | |
490 | tree p = TREE_VALUE (alloc_size); | |
491 | ||
492 | arg1 = TREE_INT_CST_LOW (TREE_VALUE (p))-1; | |
493 | if (TREE_CHAIN (p)) | |
726a989a | 494 | arg2 = TREE_INT_CST_LOW (TREE_VALUE (TREE_CHAIN (p)))-1; |
51bc54a6 | 495 | } |
b8698a0f | 496 | |
726a989a RB |
497 | if (arg1 < 0 || arg1 >= (int)gimple_call_num_args (call) |
498 | || TREE_CODE (gimple_call_arg (call, arg1)) != INTEGER_CST | |
b8698a0f | 499 | || (arg2 >= 0 |
726a989a RB |
500 | && (arg2 >= (int)gimple_call_num_args (call) |
501 | || TREE_CODE (gimple_call_arg (call, arg2)) != INTEGER_CST))) | |
b8698a0f | 502 | return unknown[object_size_type]; |
51bc54a6 | 503 | |
302db8ba | 504 | tree bytes = NULL_TREE; |
51bc54a6 DM |
505 | if (arg2 >= 0) |
506 | bytes = size_binop (MULT_EXPR, | |
726a989a RB |
507 | fold_convert (sizetype, gimple_call_arg (call, arg1)), |
508 | fold_convert (sizetype, gimple_call_arg (call, arg2))); | |
51bc54a6 | 509 | else if (arg1 >= 0) |
726a989a | 510 | bytes = fold_convert (sizetype, gimple_call_arg (call, arg1)); |
51bc54a6 | 511 | |
cc269bb6 | 512 | if (bytes && tree_fits_uhwi_p (bytes)) |
ae7e9ddd | 513 | return tree_to_uhwi (bytes); |
10a0d495 JJ |
514 | |
515 | return unknown[object_size_type]; | |
516 | } | |
517 | ||
518 | ||
519 | /* If object size is propagated from one of function's arguments directly | |
726a989a | 520 | to its return value, return that argument for GIMPLE_CALL statement CALL. |
10a0d495 JJ |
521 | Otherwise return NULL. */ |
522 | ||
523 | static tree | |
538dd0b7 | 524 | pass_through_call (const gcall *call) |
10a0d495 | 525 | { |
51feb980 JJ |
526 | unsigned rf = gimple_call_return_flags (call); |
527 | if (rf & ERF_RETURNS_ARG) | |
528 | { | |
529 | unsigned argnum = rf & ERF_RETURN_ARG_MASK; | |
530 | if (argnum < gimple_call_num_args (call)) | |
531 | return gimple_call_arg (call, argnum); | |
532 | } | |
10a0d495 | 533 | |
51feb980 JJ |
534 | /* __builtin_assume_aligned is intentionally not marked RET1. */ |
535 | if (gimple_call_builtin_p (call, BUILT_IN_ASSUME_ALIGNED)) | |
536 | return gimple_call_arg (call, 0); | |
10a0d495 JJ |
537 | |
538 | return NULL_TREE; | |
539 | } | |
540 | ||
541 | ||
05a64756 | 542 | /* Compute __builtin_object_size value for PTR and set *PSIZE to |
28a5fa54 MS |
543 | the resulting value. If the declared object is known and PDECL |
544 | is nonnull, sets *PDECL to the object's DECL. OBJECT_SIZE_TYPE | |
545 | is the second argument to __builtin_object_size. | |
546 | Returns true on success and false when the object size could not | |
547 | be determined. */ | |
10a0d495 | 548 | |
05a64756 MS |
549 | bool |
550 | compute_builtin_object_size (tree ptr, int object_size_type, | |
28a5fa54 | 551 | unsigned HOST_WIDE_INT *psize, |
f7d86b5c | 552 | tree *pdecl /* = NULL */, tree *poff /* = NULL */) |
10a0d495 JJ |
553 | { |
554 | gcc_assert (object_size_type >= 0 && object_size_type <= 3); | |
555 | ||
f7d86b5c MS |
556 | tree dummy_decl, dummy_off = size_zero_node; |
557 | if (!pdecl) | |
558 | pdecl = &dummy_decl; | |
559 | if (!poff) | |
560 | poff = &dummy_off; | |
561 | ||
05a64756 MS |
562 | /* Set to unknown and overwrite just before returning if the size |
563 | could be determined. */ | |
564 | *psize = unknown[object_size_type]; | |
565 | ||
10a0d495 JJ |
566 | if (! offset_limit) |
567 | init_offset_limit (); | |
568 | ||
569 | if (TREE_CODE (ptr) == ADDR_EXPR) | |
f7d86b5c | 570 | return addr_object_size (NULL, ptr, object_size_type, psize, pdecl, poff); |
05a64756 MS |
571 | |
572 | if (TREE_CODE (ptr) != SSA_NAME | |
573 | || !POINTER_TYPE_P (TREE_TYPE (ptr))) | |
574 | return false; | |
10a0d495 | 575 | |
05a64756 | 576 | if (computed[object_size_type] == NULL) |
10a0d495 | 577 | { |
05a64756 MS |
578 | if (optimize || object_size_type & 1) |
579 | return false; | |
580 | ||
581 | /* When not optimizing, rather than failing, make a small effort | |
582 | to determine the object size without the full benefit of | |
583 | the (costly) computation below. */ | |
584 | gimple *def = SSA_NAME_DEF_STMT (ptr); | |
585 | if (gimple_code (def) == GIMPLE_ASSIGN) | |
10a0d495 | 586 | { |
05a64756 MS |
587 | tree_code code = gimple_assign_rhs_code (def); |
588 | if (code == POINTER_PLUS_EXPR) | |
10a0d495 | 589 | { |
05a64756 MS |
590 | tree offset = gimple_assign_rhs2 (def); |
591 | ptr = gimple_assign_rhs1 (def); | |
10a0d495 | 592 | |
6182121c | 593 | if (tree_fits_shwi_p (offset) |
28a5fa54 | 594 | && compute_builtin_object_size (ptr, object_size_type, |
f7d86b5c | 595 | psize, pdecl, poff)) |
10a0d495 | 596 | { |
05a64756 MS |
597 | /* Return zero when the offset is out of bounds. */ |
598 | unsigned HOST_WIDE_INT off = tree_to_shwi (offset); | |
599 | *psize = off < *psize ? *psize - off : 0; | |
f7d86b5c | 600 | *poff = offset; |
05a64756 | 601 | return true; |
10a0d495 | 602 | } |
05a64756 MS |
603 | } |
604 | } | |
605 | return false; | |
606 | } | |
10a0d495 | 607 | |
05a64756 MS |
608 | if (!bitmap_bit_p (computed[object_size_type], SSA_NAME_VERSION (ptr))) |
609 | { | |
610 | struct object_size_info osi; | |
611 | bitmap_iterator bi; | |
612 | unsigned int i; | |
613 | ||
614 | if (num_ssa_names > object_sizes[object_size_type].length ()) | |
615 | object_sizes[object_size_type].safe_grow (num_ssa_names); | |
616 | if (dump_file) | |
617 | { | |
618 | fprintf (dump_file, "Computing %s %sobject size for ", | |
619 | (object_size_type & 2) ? "minimum" : "maximum", | |
620 | (object_size_type & 1) ? "sub" : ""); | |
621 | print_generic_expr (dump_file, ptr, dump_flags); | |
622 | fprintf (dump_file, ":\n"); | |
623 | } | |
10a0d495 | 624 | |
05a64756 MS |
625 | osi.visited = BITMAP_ALLOC (NULL); |
626 | osi.reexamine = BITMAP_ALLOC (NULL); | |
627 | osi.object_size_type = object_size_type; | |
628 | osi.depths = NULL; | |
629 | osi.stack = NULL; | |
630 | osi.tos = NULL; | |
631 | ||
632 | /* First pass: walk UD chains, compute object sizes that | |
633 | can be computed. osi.reexamine bitmap at the end will | |
634 | contain what variables were found in dependency cycles | |
635 | and therefore need to be reexamined. */ | |
636 | osi.pass = 0; | |
637 | osi.changed = false; | |
638 | collect_object_sizes_for (&osi, ptr); | |
639 | ||
640 | /* Second pass: keep recomputing object sizes of variables | |
641 | that need reexamination, until no object sizes are | |
642 | increased or all object sizes are computed. */ | |
643 | if (! bitmap_empty_p (osi.reexamine)) | |
644 | { | |
645 | bitmap reexamine = BITMAP_ALLOC (NULL); | |
646 | ||
647 | /* If looking for minimum instead of maximum object size, | |
648 | detect cases where a pointer is increased in a loop. | |
649 | Although even without this detection pass 2 would eventually | |
650 | terminate, it could take a long time. If a pointer is | |
651 | increasing this way, we need to assume 0 object size. | |
652 | E.g. p = &buf[0]; while (cond) p = p + 4; */ | |
653 | if (object_size_type & 2) | |
654 | { | |
655 | osi.depths = XCNEWVEC (unsigned int, num_ssa_names); | |
656 | osi.stack = XNEWVEC (unsigned int, num_ssa_names); | |
657 | osi.tos = osi.stack; | |
658 | osi.pass = 1; | |
659 | /* collect_object_sizes_for is changing | |
660 | osi.reexamine bitmap, so iterate over a copy. */ | |
661 | bitmap_copy (reexamine, osi.reexamine); | |
662 | EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi) | |
663 | if (bitmap_bit_p (osi.reexamine, i)) | |
664 | check_for_plus_in_loops (&osi, ssa_name (i)); | |
665 | ||
666 | free (osi.depths); | |
667 | osi.depths = NULL; | |
668 | free (osi.stack); | |
669 | osi.stack = NULL; | |
670 | osi.tos = NULL; | |
10a0d495 | 671 | } |
10a0d495 | 672 | |
05a64756 | 673 | do |
10a0d495 | 674 | { |
05a64756 MS |
675 | osi.pass = 2; |
676 | osi.changed = false; | |
677 | /* collect_object_sizes_for is changing | |
678 | osi.reexamine bitmap, so iterate over a copy. */ | |
679 | bitmap_copy (reexamine, osi.reexamine); | |
680 | EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi) | |
681 | if (bitmap_bit_p (osi.reexamine, i)) | |
10a0d495 | 682 | { |
05a64756 MS |
683 | collect_object_sizes_for (&osi, ssa_name (i)); |
684 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
685 | { | |
686 | fprintf (dump_file, "Reexamining "); | |
687 | print_generic_expr (dump_file, ssa_name (i), | |
688 | dump_flags); | |
689 | fprintf (dump_file, "\n"); | |
690 | } | |
10a0d495 JJ |
691 | } |
692 | } | |
05a64756 | 693 | while (osi.changed); |
10a0d495 | 694 | |
05a64756 | 695 | BITMAP_FREE (reexamine); |
10a0d495 | 696 | } |
05a64756 MS |
697 | EXECUTE_IF_SET_IN_BITMAP (osi.reexamine, 0, i, bi) |
698 | bitmap_set_bit (computed[object_size_type], i); | |
10a0d495 | 699 | |
05a64756 MS |
700 | /* Debugging dumps. */ |
701 | if (dump_file) | |
702 | { | |
703 | EXECUTE_IF_SET_IN_BITMAP (osi.visited, 0, i, bi) | |
704 | if (object_sizes[object_size_type][i] | |
705 | != unknown[object_size_type]) | |
706 | { | |
707 | print_generic_expr (dump_file, ssa_name (i), | |
708 | dump_flags); | |
709 | fprintf (dump_file, | |
710 | ": %s %sobject size " | |
711 | HOST_WIDE_INT_PRINT_UNSIGNED "\n", | |
712 | (object_size_type & 2) ? "minimum" : "maximum", | |
713 | (object_size_type & 1) ? "sub" : "", | |
714 | object_sizes[object_size_type][i]); | |
715 | } | |
716 | } | |
717 | ||
718 | BITMAP_FREE (osi.reexamine); | |
719 | BITMAP_FREE (osi.visited); | |
10a0d495 JJ |
720 | } |
721 | ||
05a64756 MS |
722 | *psize = object_sizes[object_size_type][SSA_NAME_VERSION (ptr)]; |
723 | return *psize != unknown[object_size_type]; | |
10a0d495 JJ |
724 | } |
725 | ||
726a989a | 726 | /* Compute object_sizes for PTR, defined to VALUE, which is not an SSA_NAME. */ |
10a0d495 JJ |
727 | |
728 | static void | |
729 | expr_object_size (struct object_size_info *osi, tree ptr, tree value) | |
730 | { | |
731 | int object_size_type = osi->object_size_type; | |
732 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
733 | unsigned HOST_WIDE_INT bytes; | |
734 | ||
735 | gcc_assert (object_sizes[object_size_type][varno] | |
736 | != unknown[object_size_type]); | |
737 | gcc_assert (osi->pass == 0); | |
738 | ||
739 | if (TREE_CODE (value) == WITH_SIZE_EXPR) | |
740 | value = TREE_OPERAND (value, 0); | |
741 | ||
742 | /* Pointer variables should have been handled by merge_object_sizes. */ | |
743 | gcc_assert (TREE_CODE (value) != SSA_NAME | |
744 | || !POINTER_TYPE_P (TREE_TYPE (value))); | |
745 | ||
746 | if (TREE_CODE (value) == ADDR_EXPR) | |
05a64756 | 747 | addr_object_size (osi, value, object_size_type, &bytes); |
10a0d495 JJ |
748 | else |
749 | bytes = unknown[object_size_type]; | |
750 | ||
751 | if ((object_size_type & 2) == 0) | |
752 | { | |
753 | if (object_sizes[object_size_type][varno] < bytes) | |
754 | object_sizes[object_size_type][varno] = bytes; | |
755 | } | |
756 | else | |
757 | { | |
758 | if (object_sizes[object_size_type][varno] > bytes) | |
759 | object_sizes[object_size_type][varno] = bytes; | |
760 | } | |
761 | } | |
762 | ||
763 | ||
726a989a RB |
764 | /* Compute object_sizes for PTR, defined to the result of a call. */ |
765 | ||
766 | static void | |
538dd0b7 | 767 | call_object_size (struct object_size_info *osi, tree ptr, gcall *call) |
726a989a RB |
768 | { |
769 | int object_size_type = osi->object_size_type; | |
770 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
771 | unsigned HOST_WIDE_INT bytes; | |
772 | ||
773 | gcc_assert (is_gimple_call (call)); | |
774 | ||
775 | gcc_assert (object_sizes[object_size_type][varno] | |
776 | != unknown[object_size_type]); | |
777 | gcc_assert (osi->pass == 0); | |
778 | ||
779 | bytes = alloc_object_size (call, object_size_type); | |
780 | ||
781 | if ((object_size_type & 2) == 0) | |
782 | { | |
783 | if (object_sizes[object_size_type][varno] < bytes) | |
784 | object_sizes[object_size_type][varno] = bytes; | |
785 | } | |
786 | else | |
787 | { | |
788 | if (object_sizes[object_size_type][varno] > bytes) | |
789 | object_sizes[object_size_type][varno] = bytes; | |
790 | } | |
791 | } | |
792 | ||
793 | ||
794 | /* Compute object_sizes for PTR, defined to an unknown value. */ | |
795 | ||
796 | static void | |
797 | unknown_object_size (struct object_size_info *osi, tree ptr) | |
798 | { | |
799 | int object_size_type = osi->object_size_type; | |
800 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
801 | unsigned HOST_WIDE_INT bytes; | |
802 | ||
803 | gcc_assert (object_sizes[object_size_type][varno] | |
804 | != unknown[object_size_type]); | |
805 | gcc_assert (osi->pass == 0); | |
806 | ||
807 | bytes = unknown[object_size_type]; | |
808 | ||
809 | if ((object_size_type & 2) == 0) | |
810 | { | |
811 | if (object_sizes[object_size_type][varno] < bytes) | |
812 | object_sizes[object_size_type][varno] = bytes; | |
813 | } | |
814 | else | |
815 | { | |
816 | if (object_sizes[object_size_type][varno] > bytes) | |
817 | object_sizes[object_size_type][varno] = bytes; | |
818 | } | |
819 | } | |
820 | ||
821 | ||
10a0d495 JJ |
822 | /* Merge object sizes of ORIG + OFFSET into DEST. Return true if |
823 | the object size might need reexamination later. */ | |
824 | ||
825 | static bool | |
826 | merge_object_sizes (struct object_size_info *osi, tree dest, tree orig, | |
827 | unsigned HOST_WIDE_INT offset) | |
828 | { | |
829 | int object_size_type = osi->object_size_type; | |
830 | unsigned int varno = SSA_NAME_VERSION (dest); | |
831 | unsigned HOST_WIDE_INT orig_bytes; | |
832 | ||
833 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
834 | return false; | |
835 | if (offset >= offset_limit) | |
836 | { | |
837 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
838 | return false; | |
839 | } | |
840 | ||
841 | if (osi->pass == 0) | |
842 | collect_object_sizes_for (osi, orig); | |
843 | ||
844 | orig_bytes = object_sizes[object_size_type][SSA_NAME_VERSION (orig)]; | |
845 | if (orig_bytes != unknown[object_size_type]) | |
846 | orig_bytes = (offset > orig_bytes) | |
07e96250 | 847 | ? HOST_WIDE_INT_0U : orig_bytes - offset; |
10a0d495 JJ |
848 | |
849 | if ((object_size_type & 2) == 0) | |
850 | { | |
851 | if (object_sizes[object_size_type][varno] < orig_bytes) | |
852 | { | |
853 | object_sizes[object_size_type][varno] = orig_bytes; | |
854 | osi->changed = true; | |
855 | } | |
856 | } | |
857 | else | |
858 | { | |
859 | if (object_sizes[object_size_type][varno] > orig_bytes) | |
860 | { | |
861 | object_sizes[object_size_type][varno] = orig_bytes; | |
862 | osi->changed = true; | |
863 | } | |
864 | } | |
865 | return bitmap_bit_p (osi->reexamine, SSA_NAME_VERSION (orig)); | |
866 | } | |
867 | ||
868 | ||
726a989a RB |
869 | /* Compute object_sizes for VAR, defined to the result of an assignment |
870 | with operator POINTER_PLUS_EXPR. Return true if the object size might | |
871 | need reexamination later. */ | |
10a0d495 JJ |
872 | |
873 | static bool | |
355fe088 | 874 | plus_stmt_object_size (struct object_size_info *osi, tree var, gimple *stmt) |
10a0d495 | 875 | { |
10a0d495 JJ |
876 | int object_size_type = osi->object_size_type; |
877 | unsigned int varno = SSA_NAME_VERSION (var); | |
878 | unsigned HOST_WIDE_INT bytes; | |
726a989a RB |
879 | tree op0, op1; |
880 | ||
70f34814 RG |
881 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) |
882 | { | |
883 | op0 = gimple_assign_rhs1 (stmt); | |
884 | op1 = gimple_assign_rhs2 (stmt); | |
885 | } | |
886 | else if (gimple_assign_rhs_code (stmt) == ADDR_EXPR) | |
887 | { | |
888 | tree rhs = TREE_OPERAND (gimple_assign_rhs1 (stmt), 0); | |
889 | gcc_assert (TREE_CODE (rhs) == MEM_REF); | |
890 | op0 = TREE_OPERAND (rhs, 0); | |
891 | op1 = TREE_OPERAND (rhs, 1); | |
892 | } | |
893 | else | |
894 | gcc_unreachable (); | |
10a0d495 JJ |
895 | |
896 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
897 | return false; | |
898 | ||
10a0d495 | 899 | /* Handle PTR + OFFSET here. */ |
5be014d5 | 900 | if (TREE_CODE (op1) == INTEGER_CST |
10a0d495 JJ |
901 | && (TREE_CODE (op0) == SSA_NAME |
902 | || TREE_CODE (op0) == ADDR_EXPR)) | |
903 | { | |
cc269bb6 | 904 | if (! tree_fits_uhwi_p (op1)) |
10a0d495 JJ |
905 | bytes = unknown[object_size_type]; |
906 | else if (TREE_CODE (op0) == SSA_NAME) | |
ae7e9ddd | 907 | return merge_object_sizes (osi, var, op0, tree_to_uhwi (op1)); |
10a0d495 JJ |
908 | else |
909 | { | |
ae7e9ddd | 910 | unsigned HOST_WIDE_INT off = tree_to_uhwi (op1); |
10a0d495 | 911 | |
726a989a | 912 | /* op0 will be ADDR_EXPR here. */ |
05a64756 | 913 | addr_object_size (osi, op0, object_size_type, &bytes); |
ac5a28a6 JH |
914 | if (bytes == unknown[object_size_type]) |
915 | ; | |
916 | else if (off > offset_limit) | |
10a0d495 JJ |
917 | bytes = unknown[object_size_type]; |
918 | else if (off > bytes) | |
919 | bytes = 0; | |
920 | else | |
921 | bytes -= off; | |
922 | } | |
923 | } | |
924 | else | |
925 | bytes = unknown[object_size_type]; | |
926 | ||
927 | if ((object_size_type & 2) == 0) | |
928 | { | |
929 | if (object_sizes[object_size_type][varno] < bytes) | |
930 | object_sizes[object_size_type][varno] = bytes; | |
931 | } | |
932 | else | |
933 | { | |
934 | if (object_sizes[object_size_type][varno] > bytes) | |
935 | object_sizes[object_size_type][varno] = bytes; | |
936 | } | |
937 | return false; | |
938 | } | |
939 | ||
940 | ||
4e71066d | 941 | /* Compute object_sizes for VAR, defined at STMT, which is |
f255541f RC |
942 | a COND_EXPR. Return true if the object size might need reexamination |
943 | later. */ | |
944 | ||
945 | static bool | |
355fe088 | 946 | cond_expr_object_size (struct object_size_info *osi, tree var, gimple *stmt) |
f255541f RC |
947 | { |
948 | tree then_, else_; | |
949 | int object_size_type = osi->object_size_type; | |
950 | unsigned int varno = SSA_NAME_VERSION (var); | |
951 | bool reexamine = false; | |
952 | ||
4e71066d | 953 | gcc_assert (gimple_assign_rhs_code (stmt) == COND_EXPR); |
f255541f RC |
954 | |
955 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
956 | return false; | |
957 | ||
4e71066d RG |
958 | then_ = gimple_assign_rhs2 (stmt); |
959 | else_ = gimple_assign_rhs3 (stmt); | |
f255541f RC |
960 | |
961 | if (TREE_CODE (then_) == SSA_NAME) | |
962 | reexamine |= merge_object_sizes (osi, var, then_, 0); | |
963 | else | |
964 | expr_object_size (osi, var, then_); | |
965 | ||
0bbb0ca1 JJ |
966 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) |
967 | return reexamine; | |
968 | ||
f255541f RC |
969 | if (TREE_CODE (else_) == SSA_NAME) |
970 | reexamine |= merge_object_sizes (osi, var, else_, 0); | |
971 | else | |
972 | expr_object_size (osi, var, else_); | |
973 | ||
974 | return reexamine; | |
975 | } | |
976 | ||
10a0d495 JJ |
977 | /* Compute object sizes for VAR. |
978 | For ADDR_EXPR an object size is the number of remaining bytes | |
619519c8 | 979 | to the end of the object (where what is considered an object depends on |
10a0d495 | 980 | OSI->object_size_type). |
726a989a | 981 | For allocation GIMPLE_CALL like malloc or calloc object size is the size |
10a0d495 | 982 | of the allocation. |
5be014d5 | 983 | For POINTER_PLUS_EXPR where second operand is a constant integer, |
10a0d495 JJ |
984 | object size is object size of the first operand minus the constant. |
985 | If the constant is bigger than the number of remaining bytes until the | |
986 | end of the object, object size is 0, but if it is instead a pointer | |
987 | subtraction, object size is unknown[object_size_type]. | |
988 | To differentiate addition from subtraction, ADDR_EXPR returns | |
989 | unknown[object_size_type] for all objects bigger than half of the address | |
990 | space, and constants less than half of the address space are considered | |
991 | addition, while bigger constants subtraction. | |
726a989a | 992 | For a memcpy like GIMPLE_CALL that always returns one of its arguments, the |
10a0d495 JJ |
993 | object size is object size of that argument. |
994 | Otherwise, object size is the maximum of object sizes of variables | |
995 | that it might be set to. */ | |
996 | ||
997 | static void | |
998 | collect_object_sizes_for (struct object_size_info *osi, tree var) | |
999 | { | |
1000 | int object_size_type = osi->object_size_type; | |
1001 | unsigned int varno = SSA_NAME_VERSION (var); | |
355fe088 | 1002 | gimple *stmt; |
10a0d495 JJ |
1003 | bool reexamine; |
1004 | ||
1005 | if (bitmap_bit_p (computed[object_size_type], varno)) | |
1006 | return; | |
1007 | ||
1008 | if (osi->pass == 0) | |
1009 | { | |
fcaa4ca4 | 1010 | if (bitmap_set_bit (osi->visited, varno)) |
10a0d495 | 1011 | { |
10a0d495 JJ |
1012 | object_sizes[object_size_type][varno] |
1013 | = (object_size_type & 2) ? -1 : 0; | |
1014 | } | |
1015 | else | |
1016 | { | |
1017 | /* Found a dependency loop. Mark the variable for later | |
1018 | re-examination. */ | |
1019 | bitmap_set_bit (osi->reexamine, varno); | |
1020 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1021 | { | |
1022 | fprintf (dump_file, "Found a dependency loop at "); | |
1023 | print_generic_expr (dump_file, var, dump_flags); | |
1024 | fprintf (dump_file, "\n"); | |
1025 | } | |
1026 | return; | |
1027 | } | |
1028 | } | |
1029 | ||
1030 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1031 | { | |
1032 | fprintf (dump_file, "Visiting use-def links for "); | |
1033 | print_generic_expr (dump_file, var, dump_flags); | |
1034 | fprintf (dump_file, "\n"); | |
1035 | } | |
1036 | ||
1037 | stmt = SSA_NAME_DEF_STMT (var); | |
1038 | reexamine = false; | |
1039 | ||
726a989a | 1040 | switch (gimple_code (stmt)) |
10a0d495 | 1041 | { |
726a989a | 1042 | case GIMPLE_ASSIGN: |
10a0d495 | 1043 | { |
70f34814 RG |
1044 | tree rhs = gimple_assign_rhs1 (stmt); |
1045 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR | |
1046 | || (gimple_assign_rhs_code (stmt) == ADDR_EXPR | |
1047 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == MEM_REF)) | |
726a989a | 1048 | reexamine = plus_stmt_object_size (osi, var, stmt); |
4e71066d RG |
1049 | else if (gimple_assign_rhs_code (stmt) == COND_EXPR) |
1050 | reexamine = cond_expr_object_size (osi, var, stmt); | |
726a989a RB |
1051 | else if (gimple_assign_single_p (stmt) |
1052 | || gimple_assign_unary_nop_p (stmt)) | |
1053 | { | |
726a989a RB |
1054 | if (TREE_CODE (rhs) == SSA_NAME |
1055 | && POINTER_TYPE_P (TREE_TYPE (rhs))) | |
1056 | reexamine = merge_object_sizes (osi, var, rhs, 0); | |
726a989a RB |
1057 | else |
1058 | expr_object_size (osi, var, rhs); | |
1059 | } | |
1060 | else | |
1061 | unknown_object_size (osi, var); | |
1062 | break; | |
1063 | } | |
f255541f | 1064 | |
726a989a RB |
1065 | case GIMPLE_CALL: |
1066 | { | |
538dd0b7 DM |
1067 | gcall *call_stmt = as_a <gcall *> (stmt); |
1068 | tree arg = pass_through_call (call_stmt); | |
726a989a RB |
1069 | if (arg) |
1070 | { | |
1071 | if (TREE_CODE (arg) == SSA_NAME | |
1072 | && POINTER_TYPE_P (TREE_TYPE (arg))) | |
1073 | reexamine = merge_object_sizes (osi, var, arg, 0); | |
726a989a RB |
1074 | else |
1075 | expr_object_size (osi, var, arg); | |
1076 | } | |
1077 | else | |
538dd0b7 | 1078 | call_object_size (osi, var, call_stmt); |
10a0d495 JJ |
1079 | break; |
1080 | } | |
1081 | ||
726a989a | 1082 | case GIMPLE_ASM: |
10a0d495 JJ |
1083 | /* Pointers defined by __asm__ statements can point anywhere. */ |
1084 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
1085 | break; | |
1086 | ||
726a989a | 1087 | case GIMPLE_NOP: |
70b5e7dc RG |
1088 | if (SSA_NAME_VAR (var) |
1089 | && TREE_CODE (SSA_NAME_VAR (var)) == PARM_DECL) | |
1090 | expr_object_size (osi, var, SSA_NAME_VAR (var)); | |
1091 | else | |
1092 | /* Uninitialized SSA names point nowhere. */ | |
1093 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
10a0d495 JJ |
1094 | break; |
1095 | ||
726a989a | 1096 | case GIMPLE_PHI: |
10a0d495 | 1097 | { |
726a989a | 1098 | unsigned i; |
10a0d495 | 1099 | |
726a989a | 1100 | for (i = 0; i < gimple_phi_num_args (stmt); i++) |
10a0d495 | 1101 | { |
726a989a | 1102 | tree rhs = gimple_phi_arg (stmt, i)->def; |
10a0d495 JJ |
1103 | |
1104 | if (object_sizes[object_size_type][varno] | |
1105 | == unknown[object_size_type]) | |
1106 | break; | |
1107 | ||
1108 | if (TREE_CODE (rhs) == SSA_NAME) | |
1109 | reexamine |= merge_object_sizes (osi, var, rhs, 0); | |
1110 | else if (osi->pass == 0) | |
1111 | expr_object_size (osi, var, rhs); | |
1112 | } | |
1113 | break; | |
1114 | } | |
726a989a | 1115 | |
10a0d495 JJ |
1116 | default: |
1117 | gcc_unreachable (); | |
1118 | } | |
1119 | ||
1120 | if (! reexamine | |
1121 | || object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
1122 | { | |
1123 | bitmap_set_bit (computed[object_size_type], varno); | |
1124 | bitmap_clear_bit (osi->reexamine, varno); | |
1125 | } | |
1126 | else | |
1127 | { | |
1128 | bitmap_set_bit (osi->reexamine, varno); | |
1129 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1130 | { | |
1131 | fprintf (dump_file, "Need to reexamine "); | |
1132 | print_generic_expr (dump_file, var, dump_flags); | |
1133 | fprintf (dump_file, "\n"); | |
1134 | } | |
1135 | } | |
1136 | } | |
1137 | ||
1138 | ||
1139 | /* Helper function for check_for_plus_in_loops. Called recursively | |
1140 | to detect loops. */ | |
1141 | ||
1142 | static void | |
1143 | check_for_plus_in_loops_1 (struct object_size_info *osi, tree var, | |
1144 | unsigned int depth) | |
1145 | { | |
355fe088 | 1146 | gimple *stmt = SSA_NAME_DEF_STMT (var); |
10a0d495 JJ |
1147 | unsigned int varno = SSA_NAME_VERSION (var); |
1148 | ||
1149 | if (osi->depths[varno]) | |
1150 | { | |
1151 | if (osi->depths[varno] != depth) | |
1152 | { | |
1153 | unsigned int *sp; | |
1154 | ||
1155 | /* Found a loop involving pointer addition. */ | |
1156 | for (sp = osi->tos; sp > osi->stack; ) | |
1157 | { | |
1158 | --sp; | |
1159 | bitmap_clear_bit (osi->reexamine, *sp); | |
1160 | bitmap_set_bit (computed[osi->object_size_type], *sp); | |
1161 | object_sizes[osi->object_size_type][*sp] = 0; | |
1162 | if (*sp == varno) | |
1163 | break; | |
1164 | } | |
1165 | } | |
1166 | return; | |
1167 | } | |
1168 | else if (! bitmap_bit_p (osi->reexamine, varno)) | |
1169 | return; | |
1170 | ||
1171 | osi->depths[varno] = depth; | |
1172 | *osi->tos++ = varno; | |
1173 | ||
726a989a | 1174 | switch (gimple_code (stmt)) |
10a0d495 | 1175 | { |
10a0d495 | 1176 | |
726a989a | 1177 | case GIMPLE_ASSIGN: |
10a0d495 | 1178 | { |
726a989a RB |
1179 | if ((gimple_assign_single_p (stmt) |
1180 | || gimple_assign_unary_nop_p (stmt)) | |
1181 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
1182 | { | |
1183 | tree rhs = gimple_assign_rhs1 (stmt); | |
1184 | ||
1185 | check_for_plus_in_loops_1 (osi, rhs, depth); | |
1186 | } | |
1187 | else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) | |
1188 | { | |
1189 | tree basevar = gimple_assign_rhs1 (stmt); | |
1190 | tree cst = gimple_assign_rhs2 (stmt); | |
1191 | ||
1192 | gcc_assert (TREE_CODE (cst) == INTEGER_CST); | |
1193 | ||
1194 | check_for_plus_in_loops_1 (osi, basevar, | |
1195 | depth + !integer_zerop (cst)); | |
1196 | } | |
1197 | else | |
1198 | gcc_unreachable (); | |
1199 | break; | |
1200 | } | |
10a0d495 | 1201 | |
726a989a RB |
1202 | case GIMPLE_CALL: |
1203 | { | |
538dd0b7 DM |
1204 | gcall *call_stmt = as_a <gcall *> (stmt); |
1205 | tree arg = pass_through_call (call_stmt); | |
726a989a RB |
1206 | if (arg) |
1207 | { | |
1208 | if (TREE_CODE (arg) == SSA_NAME) | |
1209 | check_for_plus_in_loops_1 (osi, arg, depth); | |
1210 | else | |
1211 | gcc_unreachable (); | |
1212 | } | |
1213 | break; | |
10a0d495 | 1214 | } |
726a989a RB |
1215 | |
1216 | case GIMPLE_PHI: | |
10a0d495 | 1217 | { |
726a989a | 1218 | unsigned i; |
10a0d495 | 1219 | |
726a989a | 1220 | for (i = 0; i < gimple_phi_num_args (stmt); i++) |
10a0d495 | 1221 | { |
726a989a | 1222 | tree rhs = gimple_phi_arg (stmt, i)->def; |
10a0d495 JJ |
1223 | |
1224 | if (TREE_CODE (rhs) == SSA_NAME) | |
1225 | check_for_plus_in_loops_1 (osi, rhs, depth); | |
1226 | } | |
1227 | break; | |
1228 | } | |
726a989a | 1229 | |
10a0d495 JJ |
1230 | default: |
1231 | gcc_unreachable (); | |
1232 | } | |
1233 | ||
1234 | osi->depths[varno] = 0; | |
1235 | osi->tos--; | |
1236 | } | |
1237 | ||
1238 | ||
1239 | /* Check if some pointer we are computing object size of is being increased | |
1240 | within a loop. If yes, assume all the SSA variables participating in | |
1241 | that loop have minimum object sizes 0. */ | |
1242 | ||
1243 | static void | |
1244 | check_for_plus_in_loops (struct object_size_info *osi, tree var) | |
1245 | { | |
355fe088 | 1246 | gimple *stmt = SSA_NAME_DEF_STMT (var); |
10a0d495 | 1247 | |
726a989a RB |
1248 | /* NOTE: In the pre-tuples code, we handled a CALL_EXPR here, |
1249 | and looked for a POINTER_PLUS_EXPR in the pass-through | |
1250 | argument, if any. In GIMPLE, however, such an expression | |
1251 | is not a valid call operand. */ | |
10a0d495 | 1252 | |
726a989a RB |
1253 | if (is_gimple_assign (stmt) |
1254 | && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) | |
1255 | { | |
1256 | tree basevar = gimple_assign_rhs1 (stmt); | |
1257 | tree cst = gimple_assign_rhs2 (stmt); | |
b8698a0f | 1258 | |
726a989a RB |
1259 | gcc_assert (TREE_CODE (cst) == INTEGER_CST); |
1260 | ||
1261 | if (integer_zerop (cst)) | |
1262 | return; | |
1263 | ||
1264 | osi->depths[SSA_NAME_VERSION (basevar)] = 1; | |
1265 | *osi->tos++ = SSA_NAME_VERSION (basevar); | |
1266 | check_for_plus_in_loops_1 (osi, var, 2); | |
1267 | osi->depths[SSA_NAME_VERSION (basevar)] = 0; | |
1268 | osi->tos--; | |
10a0d495 JJ |
1269 | } |
1270 | } | |
1271 | ||
1272 | ||
1273 | /* Initialize data structures for the object size computation. */ | |
1274 | ||
1275 | void | |
1276 | init_object_sizes (void) | |
1277 | { | |
1278 | int object_size_type; | |
1279 | ||
db84d11e | 1280 | if (computed[0]) |
10a0d495 JJ |
1281 | return; |
1282 | ||
1283 | for (object_size_type = 0; object_size_type <= 3; object_size_type++) | |
1284 | { | |
db84d11e | 1285 | object_sizes[object_size_type].safe_grow (num_ssa_names); |
10a0d495 JJ |
1286 | computed[object_size_type] = BITMAP_ALLOC (NULL); |
1287 | } | |
1288 | ||
1289 | init_offset_limit (); | |
1290 | } | |
1291 | ||
1292 | ||
1293 | /* Destroy data structures after the object size computation. */ | |
1294 | ||
eb07c7cf | 1295 | void |
10a0d495 JJ |
1296 | fini_object_sizes (void) |
1297 | { | |
1298 | int object_size_type; | |
1299 | ||
1300 | for (object_size_type = 0; object_size_type <= 3; object_size_type++) | |
1301 | { | |
db84d11e | 1302 | object_sizes[object_size_type].release (); |
10a0d495 | 1303 | BITMAP_FREE (computed[object_size_type]); |
10a0d495 JJ |
1304 | } |
1305 | } | |
1306 | ||
1307 | ||
1308 | /* Simple pass to optimize all __builtin_object_size () builtins. */ | |
1309 | ||
be55bfe6 TS |
1310 | namespace { |
1311 | ||
1312 | const pass_data pass_data_object_sizes = | |
1313 | { | |
1314 | GIMPLE_PASS, /* type */ | |
1315 | "objsz", /* name */ | |
1316 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
1317 | TV_NONE, /* tv_id */ |
1318 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1319 | 0, /* properties_provided */ | |
1320 | 0, /* properties_destroyed */ | |
1321 | 0, /* todo_flags_start */ | |
3bea341f | 1322 | 0, /* todo_flags_finish */ |
be55bfe6 TS |
1323 | }; |
1324 | ||
1325 | class pass_object_sizes : public gimple_opt_pass | |
1326 | { | |
1327 | public: | |
1328 | pass_object_sizes (gcc::context *ctxt) | |
813ccd83 | 1329 | : gimple_opt_pass (pass_data_object_sizes, ctxt), insert_min_max_p (false) |
be55bfe6 TS |
1330 | {} |
1331 | ||
1332 | /* opt_pass methods: */ | |
1333 | opt_pass * clone () { return new pass_object_sizes (m_ctxt); } | |
813ccd83 TV |
1334 | void set_pass_param (unsigned int n, bool param) |
1335 | { | |
1336 | gcc_assert (n == 0); | |
1337 | insert_min_max_p = param; | |
1338 | } | |
be55bfe6 TS |
1339 | virtual unsigned int execute (function *); |
1340 | ||
813ccd83 TV |
1341 | private: |
1342 | /* Determines whether the pass instance creates MIN/MAX_EXPRs. */ | |
1343 | bool insert_min_max_p; | |
be55bfe6 TS |
1344 | }; // class pass_object_sizes |
1345 | ||
1e080ab4 RB |
1346 | /* Dummy valueize function. */ |
1347 | ||
1348 | static tree | |
1349 | do_valueize (tree t) | |
1350 | { | |
1351 | return t; | |
1352 | } | |
1353 | ||
be55bfe6 TS |
1354 | unsigned int |
1355 | pass_object_sizes::execute (function *fun) | |
10a0d495 JJ |
1356 | { |
1357 | basic_block bb; | |
be55bfe6 | 1358 | FOR_EACH_BB_FN (bb, fun) |
10a0d495 | 1359 | { |
726a989a RB |
1360 | gimple_stmt_iterator i; |
1361 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) | |
10a0d495 | 1362 | { |
1eadb567 | 1363 | tree result; |
355fe088 | 1364 | gimple *call = gsi_stmt (i); |
1eadb567 | 1365 | if (!gimple_call_builtin_p (call, BUILT_IN_OBJECT_SIZE)) |
10a0d495 JJ |
1366 | continue; |
1367 | ||
1368 | init_object_sizes (); | |
672ff0b6 | 1369 | |
813ccd83 | 1370 | /* If insert_min_max_p, only attempt to fold |
672ff0b6 JJ |
1371 | __builtin_object_size (x, 1) and __builtin_object_size (x, 3), |
1372 | and rather than folding the builtin to the constant if any, | |
1373 | create a MIN_EXPR or MAX_EXPR of the __builtin_object_size | |
1374 | call result and the computed constant. */ | |
813ccd83 | 1375 | if (insert_min_max_p) |
672ff0b6 JJ |
1376 | { |
1377 | tree ost = gimple_call_arg (call, 1); | |
1378 | if (tree_fits_uhwi_p (ost)) | |
1379 | { | |
1380 | unsigned HOST_WIDE_INT object_size_type = tree_to_uhwi (ost); | |
1381 | tree ptr = gimple_call_arg (call, 0); | |
1382 | tree lhs = gimple_call_lhs (call); | |
1383 | if ((object_size_type == 1 || object_size_type == 3) | |
1384 | && (TREE_CODE (ptr) == ADDR_EXPR | |
1385 | || TREE_CODE (ptr) == SSA_NAME) | |
1386 | && lhs) | |
1387 | { | |
1388 | tree type = TREE_TYPE (lhs); | |
05a64756 MS |
1389 | unsigned HOST_WIDE_INT bytes; |
1390 | if (compute_builtin_object_size (ptr, object_size_type, | |
1391 | &bytes) | |
672ff0b6 JJ |
1392 | && wi::fits_to_tree_p (bytes, type)) |
1393 | { | |
1394 | tree tem = make_ssa_name (type); | |
1395 | gimple_call_set_lhs (call, tem); | |
1396 | enum tree_code code | |
1397 | = object_size_type == 1 ? MIN_EXPR : MAX_EXPR; | |
1398 | tree cst = build_int_cstu (type, bytes); | |
355fe088 TS |
1399 | gimple *g |
1400 | = gimple_build_assign (lhs, code, tem, cst); | |
672ff0b6 JJ |
1401 | gsi_insert_after (&i, g, GSI_NEW_STMT); |
1402 | update_stmt (call); | |
1403 | } | |
1404 | } | |
1405 | } | |
1406 | continue; | |
1407 | } | |
1408 | ||
1e080ab4 RB |
1409 | tree lhs = gimple_call_lhs (call); |
1410 | if (!lhs) | |
1411 | continue; | |
1412 | ||
1413 | result = gimple_fold_stmt_to_constant (call, do_valueize); | |
10a0d495 JJ |
1414 | if (!result) |
1415 | { | |
672ff0b6 JJ |
1416 | tree ost = gimple_call_arg (call, 1); |
1417 | ||
1418 | if (tree_fits_uhwi_p (ost)) | |
10a0d495 | 1419 | { |
672ff0b6 | 1420 | unsigned HOST_WIDE_INT object_size_type = tree_to_uhwi (ost); |
10a0d495 | 1421 | |
672ff0b6 JJ |
1422 | if (object_size_type < 2) |
1423 | result = fold_convert (size_type_node, | |
1424 | integer_minus_one_node); | |
1425 | else if (object_size_type < 4) | |
1426 | result = build_zero_cst (size_type_node); | |
10a0d495 JJ |
1427 | } |
1428 | ||
1429 | if (!result) | |
1430 | continue; | |
1431 | } | |
1432 | ||
1eadb567 RB |
1433 | gcc_assert (TREE_CODE (result) == INTEGER_CST); |
1434 | ||
10a0d495 JJ |
1435 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1436 | { | |
1437 | fprintf (dump_file, "Simplified\n "); | |
726a989a | 1438 | print_gimple_stmt (dump_file, call, 0, dump_flags); |
1eadb567 | 1439 | fprintf (dump_file, " to "); |
ef6cb4c7 | 1440 | print_generic_expr (dump_file, result); |
1eadb567 | 1441 | fprintf (dump_file, "\n"); |
10a0d495 JJ |
1442 | } |
1443 | ||
1eadb567 | 1444 | /* Propagate into all uses and fold those stmts. */ |
9ecb3ecc JJ |
1445 | if (!SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) |
1446 | replace_uses_by (lhs, result); | |
1447 | else | |
1448 | replace_call_with_value (&i, result); | |
10a0d495 JJ |
1449 | } |
1450 | } | |
1451 | ||
1452 | fini_object_sizes (); | |
c2924966 | 1453 | return 0; |
10a0d495 JJ |
1454 | } |
1455 | ||
27a4cd48 DM |
1456 | } // anon namespace |
1457 | ||
1458 | gimple_opt_pass * | |
1459 | make_pass_object_sizes (gcc::context *ctxt) | |
1460 | { | |
1461 | return new pass_object_sizes (ctxt); | |
1462 | } |