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0a39fd54 | 1 | /* __builtin_object_size (ptr, object_size_type) computation |
aad93da1 | 2 | Copyright (C) 2004-2017 Free Software Foundation, Inc. |
0a39fd54 | 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 | |
8c4c00c1 | 9 | the Free Software Foundation; either version 3, or (at your option) |
0a39fd54 | 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 | |
8c4c00c1 | 18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
0a39fd54 | 20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
9ef16211 | 24 | #include "backend.h" |
0a39fd54 | 25 | #include "tree.h" |
9ef16211 | 26 | #include "gimple.h" |
7c29e30e | 27 | #include "tree-pass.h" |
9ef16211 | 28 | #include "ssa.h" |
7c29e30e | 29 | #include "gimple-pretty-print.h" |
b20a8bb4 | 30 | #include "fold-const.h" |
9ed99284 | 31 | #include "tree-object-size.h" |
bc61cadb | 32 | #include "gimple-fold.h" |
dcf1a1ec | 33 | #include "gimple-iterator.h" |
1603b4dc | 34 | #include "tree-cfg.h" |
30a86690 | 35 | #include "stringpool.h" |
36 | #include "attribs.h" | |
0a39fd54 | 37 | |
38 | struct object_size_info | |
39 | { | |
40 | int object_size_type; | |
487798e2 | 41 | unsigned char pass; |
0a39fd54 | 42 | bool changed; |
487798e2 | 43 | bitmap visited, reexamine; |
0a39fd54 | 44 | unsigned int *depths; |
45 | unsigned int *stack, *tos; | |
46 | }; | |
47 | ||
fb089e65 | 48 | static const unsigned HOST_WIDE_INT unknown[4] = { |
49 | HOST_WIDE_INT_M1U, | |
50 | HOST_WIDE_INT_M1U, | |
51 | 0, | |
52 | 0 | |
53 | }; | |
0a39fd54 | 54 | |
b4b34335 | 55 | static tree compute_object_offset (const_tree, const_tree); |
4e91a07b | 56 | static bool addr_object_size (struct object_size_info *, |
57 | const_tree, int, unsigned HOST_WIDE_INT *); | |
1a91d914 | 58 | static unsigned HOST_WIDE_INT alloc_object_size (const gcall *, int); |
59 | static tree pass_through_call (const gcall *); | |
0a39fd54 | 60 | static void collect_object_sizes_for (struct object_size_info *, tree); |
61 | static void expr_object_size (struct object_size_info *, tree, tree); | |
62 | static bool merge_object_sizes (struct object_size_info *, tree, tree, | |
63 | unsigned HOST_WIDE_INT); | |
24500bba | 64 | static bool plus_stmt_object_size (struct object_size_info *, tree, gimple *); |
65 | static bool cond_expr_object_size (struct object_size_info *, tree, gimple *); | |
0a39fd54 | 66 | static void init_offset_limit (void); |
67 | static void check_for_plus_in_loops (struct object_size_info *, tree); | |
68 | static void check_for_plus_in_loops_1 (struct object_size_info *, tree, | |
69 | unsigned int); | |
70 | ||
71 | /* object_sizes[0] is upper bound for number of bytes till the end of | |
72 | the object. | |
73 | object_sizes[1] is upper bound for number of bytes till the end of | |
74 | the subobject (innermost array or field with address taken). | |
75 | object_sizes[2] is lower bound for number of bytes till the end of | |
76 | the object and object_sizes[3] lower bound for subobject. */ | |
194eb161 | 77 | static vec<unsigned HOST_WIDE_INT> object_sizes[4]; |
0a39fd54 | 78 | |
79 | /* Bitmaps what object sizes have been computed already. */ | |
80 | static bitmap computed[4]; | |
81 | ||
82 | /* Maximum value of offset we consider to be addition. */ | |
83 | static unsigned HOST_WIDE_INT offset_limit; | |
84 | ||
85 | ||
86 | /* Initialize OFFSET_LIMIT variable. */ | |
87 | static void | |
88 | init_offset_limit (void) | |
89 | { | |
e913b5cd | 90 | if (tree_fits_uhwi_p (TYPE_MAX_VALUE (sizetype))) |
91 | offset_limit = tree_to_uhwi (TYPE_MAX_VALUE (sizetype)); | |
0a39fd54 | 92 | else |
93 | offset_limit = -1; | |
94 | offset_limit /= 2; | |
95 | } | |
96 | ||
97 | ||
98 | /* Compute offset of EXPR within VAR. Return error_mark_node | |
99 | if unknown. */ | |
100 | ||
101 | static tree | |
b4b34335 | 102 | compute_object_offset (const_tree expr, const_tree var) |
0a39fd54 | 103 | { |
104 | enum tree_code code = PLUS_EXPR; | |
105 | tree base, off, t; | |
106 | ||
107 | if (expr == var) | |
108 | return size_zero_node; | |
109 | ||
110 | switch (TREE_CODE (expr)) | |
111 | { | |
112 | case COMPONENT_REF: | |
113 | base = compute_object_offset (TREE_OPERAND (expr, 0), var); | |
114 | if (base == error_mark_node) | |
115 | return base; | |
116 | ||
117 | t = TREE_OPERAND (expr, 1); | |
118 | off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t), | |
e913b5cd | 119 | size_int (tree_to_uhwi (DECL_FIELD_BIT_OFFSET (t)) |
0a39fd54 | 120 | / BITS_PER_UNIT)); |
121 | break; | |
122 | ||
123 | case REALPART_EXPR: | |
72dd6141 | 124 | CASE_CONVERT: |
0a39fd54 | 125 | case VIEW_CONVERT_EXPR: |
126 | case NON_LVALUE_EXPR: | |
127 | return compute_object_offset (TREE_OPERAND (expr, 0), var); | |
128 | ||
129 | case IMAGPART_EXPR: | |
130 | base = compute_object_offset (TREE_OPERAND (expr, 0), var); | |
131 | if (base == error_mark_node) | |
132 | return base; | |
133 | ||
134 | off = TYPE_SIZE_UNIT (TREE_TYPE (expr)); | |
135 | break; | |
136 | ||
137 | case ARRAY_REF: | |
138 | base = compute_object_offset (TREE_OPERAND (expr, 0), var); | |
139 | if (base == error_mark_node) | |
140 | return base; | |
141 | ||
142 | t = TREE_OPERAND (expr, 1); | |
30a04590 | 143 | tree low_bound, unit_size; |
144 | low_bound = array_ref_low_bound (CONST_CAST_TREE (expr)); | |
145 | unit_size = array_ref_element_size (CONST_CAST_TREE (expr)); | |
146 | if (! integer_zerop (low_bound)) | |
147 | t = fold_build2 (MINUS_EXPR, TREE_TYPE (t), t, low_bound); | |
0a39fd54 | 148 | if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0) |
149 | { | |
150 | code = MINUS_EXPR; | |
151 | t = fold_build1 (NEGATE_EXPR, TREE_TYPE (t), t); | |
152 | } | |
535664e3 | 153 | t = fold_convert (sizetype, t); |
30a04590 | 154 | off = size_binop (MULT_EXPR, unit_size, t); |
0a39fd54 | 155 | break; |
156 | ||
182cf5a9 | 157 | case MEM_REF: |
158 | gcc_assert (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR); | |
e913b5cd | 159 | return wide_int_to_tree (sizetype, mem_ref_offset (expr)); |
182cf5a9 | 160 | |
0a39fd54 | 161 | default: |
162 | return error_mark_node; | |
163 | } | |
164 | ||
165 | return size_binop (code, base, off); | |
166 | } | |
167 | ||
168 | ||
169 | /* Compute __builtin_object_size for PTR, which is a ADDR_EXPR. | |
170 | OBJECT_SIZE_TYPE is the second argument from __builtin_object_size. | |
171 | If unknown, return unknown[object_size_type]. */ | |
172 | ||
4e91a07b | 173 | static bool |
fbc1ccbc | 174 | addr_object_size (struct object_size_info *osi, const_tree ptr, |
4e91a07b | 175 | int object_size_type, unsigned HOST_WIDE_INT *psize) |
0a39fd54 | 176 | { |
fbc1ccbc | 177 | tree pt_var, pt_var_size = NULL_TREE, var_size, bytes; |
0a39fd54 | 178 | |
179 | gcc_assert (TREE_CODE (ptr) == ADDR_EXPR); | |
180 | ||
4e91a07b | 181 | /* Set to unknown and overwrite just before returning if the size |
182 | could be determined. */ | |
183 | *psize = unknown[object_size_type]; | |
184 | ||
0a39fd54 | 185 | pt_var = TREE_OPERAND (ptr, 0); |
97a7a862 | 186 | while (handled_component_p (pt_var)) |
187 | pt_var = TREE_OPERAND (pt_var, 0); | |
0a39fd54 | 188 | |
189 | if (pt_var | |
97a7a862 | 190 | && TREE_CODE (pt_var) == MEM_REF) |
0a39fd54 | 191 | { |
fbc1ccbc | 192 | unsigned HOST_WIDE_INT sz; |
0a39fd54 | 193 | |
97a7a862 | 194 | if (!osi || (object_size_type & 1) != 0 |
cd45d8fd | 195 | || TREE_CODE (TREE_OPERAND (pt_var, 0)) != SSA_NAME) |
182cf5a9 | 196 | { |
4e91a07b | 197 | compute_builtin_object_size (TREE_OPERAND (pt_var, 0), |
198 | object_size_type & ~1, &sz); | |
182cf5a9 | 199 | } |
fbc1ccbc | 200 | else |
0a39fd54 | 201 | { |
fbc1ccbc | 202 | tree var = TREE_OPERAND (pt_var, 0); |
203 | if (osi->pass == 0) | |
204 | collect_object_sizes_for (osi, var); | |
205 | if (bitmap_bit_p (computed[object_size_type], | |
206 | SSA_NAME_VERSION (var))) | |
207 | sz = object_sizes[object_size_type][SSA_NAME_VERSION (var)]; | |
208 | else | |
209 | sz = unknown[object_size_type]; | |
97a7a862 | 210 | } |
211 | if (sz != unknown[object_size_type]) | |
212 | { | |
ab2c1de8 | 213 | offset_int dsz = wi::sub (sz, mem_ref_offset (pt_var)); |
796b6678 | 214 | if (wi::neg_p (dsz)) |
97a7a862 | 215 | sz = 0; |
796b6678 | 216 | else if (wi::fits_uhwi_p (dsz)) |
cf8f0e63 | 217 | sz = dsz.to_uhwi (); |
182cf5a9 | 218 | else |
97a7a862 | 219 | sz = unknown[object_size_type]; |
fbc1ccbc | 220 | } |
221 | ||
222 | if (sz != unknown[object_size_type] && sz < offset_limit) | |
223 | pt_var_size = size_int (sz); | |
224 | } | |
dda02ea2 | 225 | else if (pt_var |
226 | && DECL_P (pt_var) | |
e913b5cd | 227 | && tree_fits_uhwi_p (DECL_SIZE_UNIT (pt_var)) |
aa59f000 | 228 | && tree_to_uhwi (DECL_SIZE_UNIT (pt_var)) < offset_limit) |
dda02ea2 | 229 | pt_var_size = DECL_SIZE_UNIT (pt_var); |
fbc1ccbc | 230 | else if (pt_var |
97a7a862 | 231 | && TREE_CODE (pt_var) == STRING_CST |
fbc1ccbc | 232 | && TYPE_SIZE_UNIT (TREE_TYPE (pt_var)) |
e913b5cd | 233 | && tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (pt_var))) |
aa59f000 | 234 | && tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (pt_var))) |
fbc1ccbc | 235 | < offset_limit) |
236 | pt_var_size = TYPE_SIZE_UNIT (TREE_TYPE (pt_var)); | |
237 | else | |
4e91a07b | 238 | return false; |
fbc1ccbc | 239 | |
240 | if (pt_var != TREE_OPERAND (ptr, 0)) | |
241 | { | |
242 | tree var; | |
0a39fd54 | 243 | |
fbc1ccbc | 244 | if (object_size_type & 1) |
245 | { | |
246 | var = TREE_OPERAND (ptr, 0); | |
247 | ||
248 | while (var != pt_var | |
249 | && TREE_CODE (var) != BIT_FIELD_REF | |
250 | && TREE_CODE (var) != COMPONENT_REF | |
251 | && TREE_CODE (var) != ARRAY_REF | |
252 | && TREE_CODE (var) != ARRAY_RANGE_REF | |
253 | && TREE_CODE (var) != REALPART_EXPR | |
254 | && TREE_CODE (var) != IMAGPART_EXPR) | |
255 | var = TREE_OPERAND (var, 0); | |
256 | if (var != pt_var && TREE_CODE (var) == ARRAY_REF) | |
ffbeca59 | 257 | var = TREE_OPERAND (var, 0); |
fbc1ccbc | 258 | if (! TYPE_SIZE_UNIT (TREE_TYPE (var)) |
e913b5cd | 259 | || ! tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (var))) |
fbc1ccbc | 260 | || (pt_var_size |
261 | && tree_int_cst_lt (pt_var_size, | |
262 | TYPE_SIZE_UNIT (TREE_TYPE (var))))) | |
263 | var = pt_var; | |
182cf5a9 | 264 | else if (var != pt_var && TREE_CODE (pt_var) == MEM_REF) |
0a39fd54 | 265 | { |
fbc1ccbc | 266 | tree v = var; |
267 | /* For &X->fld, compute object size only if fld isn't the last | |
268 | field, as struct { int i; char c[1]; } is often used instead | |
269 | of flexible array member. */ | |
270 | while (v && v != pt_var) | |
271 | switch (TREE_CODE (v)) | |
272 | { | |
273 | case ARRAY_REF: | |
274 | if (TYPE_SIZE_UNIT (TREE_TYPE (TREE_OPERAND (v, 0))) | |
275 | && TREE_CODE (TREE_OPERAND (v, 1)) == INTEGER_CST) | |
276 | { | |
277 | tree domain | |
278 | = TYPE_DOMAIN (TREE_TYPE (TREE_OPERAND (v, 0))); | |
279 | if (domain | |
280 | && TYPE_MAX_VALUE (domain) | |
281 | && TREE_CODE (TYPE_MAX_VALUE (domain)) | |
282 | == INTEGER_CST | |
283 | && tree_int_cst_lt (TREE_OPERAND (v, 1), | |
284 | TYPE_MAX_VALUE (domain))) | |
285 | { | |
286 | v = NULL_TREE; | |
287 | break; | |
288 | } | |
289 | } | |
290 | v = TREE_OPERAND (v, 0); | |
291 | break; | |
292 | case REALPART_EXPR: | |
293 | case IMAGPART_EXPR: | |
294 | v = NULL_TREE; | |
295 | break; | |
296 | case COMPONENT_REF: | |
5dc67ab1 | 297 | if (TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE) |
298 | { | |
299 | v = NULL_TREE; | |
300 | break; | |
301 | } | |
ffbeca59 | 302 | while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) |
303 | if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
304 | != UNION_TYPE | |
305 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
306 | != QUAL_UNION_TYPE) | |
307 | break; | |
308 | else | |
309 | v = TREE_OPERAND (v, 0); | |
310 | if (TREE_CODE (v) == COMPONENT_REF | |
311 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
312 | == RECORD_TYPE) | |
fbc1ccbc | 313 | { |
1767a056 | 314 | tree fld_chain = DECL_CHAIN (TREE_OPERAND (v, 1)); |
315 | for (; fld_chain; fld_chain = DECL_CHAIN (fld_chain)) | |
5dc67ab1 | 316 | if (TREE_CODE (fld_chain) == FIELD_DECL) |
317 | break; | |
318 | ||
319 | if (fld_chain) | |
320 | { | |
321 | v = NULL_TREE; | |
fbc1ccbc | 322 | break; |
5dc67ab1 | 323 | } |
ffbeca59 | 324 | v = TREE_OPERAND (v, 0); |
fbc1ccbc | 325 | } |
ffbeca59 | 326 | while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) |
327 | if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
328 | != UNION_TYPE | |
329 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
330 | != QUAL_UNION_TYPE) | |
5dc67ab1 | 331 | break; |
332 | else | |
333 | v = TREE_OPERAND (v, 0); | |
ffbeca59 | 334 | if (v != pt_var) |
5dc67ab1 | 335 | v = NULL_TREE; |
336 | else | |
337 | v = pt_var; | |
fbc1ccbc | 338 | break; |
339 | default: | |
340 | v = pt_var; | |
341 | break; | |
342 | } | |
343 | if (v == pt_var) | |
0a39fd54 | 344 | var = pt_var; |
345 | } | |
fbc1ccbc | 346 | } |
347 | else | |
348 | var = pt_var; | |
0a39fd54 | 349 | |
fbc1ccbc | 350 | if (var != pt_var) |
351 | var_size = TYPE_SIZE_UNIT (TREE_TYPE (var)); | |
352 | else if (!pt_var_size) | |
4e91a07b | 353 | return false; |
fbc1ccbc | 354 | else |
355 | var_size = pt_var_size; | |
356 | bytes = compute_object_offset (TREE_OPERAND (ptr, 0), var); | |
357 | if (bytes != error_mark_node) | |
358 | { | |
359 | if (TREE_CODE (bytes) == INTEGER_CST | |
360 | && tree_int_cst_lt (var_size, bytes)) | |
361 | bytes = size_zero_node; | |
362 | else | |
363 | bytes = size_binop (MINUS_EXPR, var_size, bytes); | |
364 | } | |
365 | if (var != pt_var | |
366 | && pt_var_size | |
182cf5a9 | 367 | && TREE_CODE (pt_var) == MEM_REF |
fbc1ccbc | 368 | && bytes != error_mark_node) |
369 | { | |
370 | tree bytes2 = compute_object_offset (TREE_OPERAND (ptr, 0), pt_var); | |
371 | if (bytes2 != error_mark_node) | |
0a39fd54 | 372 | { |
fbc1ccbc | 373 | if (TREE_CODE (bytes2) == INTEGER_CST |
374 | && tree_int_cst_lt (pt_var_size, bytes2)) | |
375 | bytes2 = size_zero_node; | |
0a39fd54 | 376 | else |
56b5c963 | 377 | bytes2 = size_binop (MINUS_EXPR, pt_var_size, bytes2); |
fbc1ccbc | 378 | bytes = size_binop (MIN_EXPR, bytes, bytes2); |
0a39fd54 | 379 | } |
380 | } | |
0a39fd54 | 381 | } |
fbc1ccbc | 382 | else if (!pt_var_size) |
4e91a07b | 383 | return false; |
fbc1ccbc | 384 | else |
385 | bytes = pt_var_size; | |
386 | ||
e913b5cd | 387 | if (tree_fits_uhwi_p (bytes)) |
4e91a07b | 388 | { |
389 | *psize = tree_to_uhwi (bytes); | |
390 | return true; | |
391 | } | |
0a39fd54 | 392 | |
4e91a07b | 393 | return false; |
0a39fd54 | 394 | } |
395 | ||
396 | ||
75a70cf9 | 397 | /* Compute __builtin_object_size for CALL, which is a GIMPLE_CALL. |
0a39fd54 | 398 | Handles various allocation calls. OBJECT_SIZE_TYPE is the second |
399 | argument from __builtin_object_size. If unknown, return | |
400 | unknown[object_size_type]. */ | |
401 | ||
402 | static unsigned HOST_WIDE_INT | |
1a91d914 | 403 | alloc_object_size (const gcall *call, int object_size_type) |
0a39fd54 | 404 | { |
c2f47e15 | 405 | tree callee, bytes = NULL_TREE; |
4a29c97c | 406 | tree alloc_size; |
407 | int arg1 = -1, arg2 = -1; | |
0a39fd54 | 408 | |
75a70cf9 | 409 | gcc_assert (is_gimple_call (call)); |
0a39fd54 | 410 | |
75a70cf9 | 411 | callee = gimple_call_fndecl (call); |
4a29c97c | 412 | if (!callee) |
413 | return unknown[object_size_type]; | |
414 | ||
9af5ce0c | 415 | alloc_size = lookup_attribute ("alloc_size", |
416 | TYPE_ATTRIBUTES (TREE_TYPE (callee))); | |
4a29c97c | 417 | if (alloc_size && TREE_VALUE (alloc_size)) |
418 | { | |
419 | tree p = TREE_VALUE (alloc_size); | |
420 | ||
f9ae6f95 | 421 | arg1 = TREE_INT_CST_LOW (TREE_VALUE (p))-1; |
4a29c97c | 422 | if (TREE_CHAIN (p)) |
f9ae6f95 | 423 | arg2 = TREE_INT_CST_LOW (TREE_VALUE (TREE_CHAIN (p)))-1; |
4a29c97c | 424 | } |
48e1416a | 425 | |
4a29c97c | 426 | if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) |
0a39fd54 | 427 | switch (DECL_FUNCTION_CODE (callee)) |
428 | { | |
4a29c97c | 429 | case BUILT_IN_CALLOC: |
430 | arg2 = 1; | |
431 | /* fall through */ | |
0a39fd54 | 432 | case BUILT_IN_MALLOC: |
2b34677f | 433 | CASE_BUILT_IN_ALLOCA: |
4a29c97c | 434 | arg1 = 0; |
0a39fd54 | 435 | default: |
436 | break; | |
437 | } | |
438 | ||
75a70cf9 | 439 | if (arg1 < 0 || arg1 >= (int)gimple_call_num_args (call) |
440 | || TREE_CODE (gimple_call_arg (call, arg1)) != INTEGER_CST | |
48e1416a | 441 | || (arg2 >= 0 |
75a70cf9 | 442 | && (arg2 >= (int)gimple_call_num_args (call) |
443 | || TREE_CODE (gimple_call_arg (call, arg2)) != INTEGER_CST))) | |
48e1416a | 444 | return unknown[object_size_type]; |
4a29c97c | 445 | |
446 | if (arg2 >= 0) | |
447 | bytes = size_binop (MULT_EXPR, | |
75a70cf9 | 448 | fold_convert (sizetype, gimple_call_arg (call, arg1)), |
449 | fold_convert (sizetype, gimple_call_arg (call, arg2))); | |
4a29c97c | 450 | else if (arg1 >= 0) |
75a70cf9 | 451 | bytes = fold_convert (sizetype, gimple_call_arg (call, arg1)); |
4a29c97c | 452 | |
e913b5cd | 453 | if (bytes && tree_fits_uhwi_p (bytes)) |
454 | return tree_to_uhwi (bytes); | |
0a39fd54 | 455 | |
456 | return unknown[object_size_type]; | |
457 | } | |
458 | ||
459 | ||
460 | /* If object size is propagated from one of function's arguments directly | |
75a70cf9 | 461 | to its return value, return that argument for GIMPLE_CALL statement CALL. |
0a39fd54 | 462 | Otherwise return NULL. */ |
463 | ||
464 | static tree | |
1a91d914 | 465 | pass_through_call (const gcall *call) |
0a39fd54 | 466 | { |
75a70cf9 | 467 | tree callee = gimple_call_fndecl (call); |
0a39fd54 | 468 | |
469 | if (callee | |
470 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) | |
471 | switch (DECL_FUNCTION_CODE (callee)) | |
472 | { | |
473 | case BUILT_IN_MEMCPY: | |
474 | case BUILT_IN_MEMMOVE: | |
475 | case BUILT_IN_MEMSET: | |
476 | case BUILT_IN_STRCPY: | |
477 | case BUILT_IN_STRNCPY: | |
478 | case BUILT_IN_STRCAT: | |
479 | case BUILT_IN_STRNCAT: | |
480 | case BUILT_IN_MEMCPY_CHK: | |
481 | case BUILT_IN_MEMMOVE_CHK: | |
482 | case BUILT_IN_MEMSET_CHK: | |
483 | case BUILT_IN_STRCPY_CHK: | |
484 | case BUILT_IN_STRNCPY_CHK: | |
1063acde | 485 | case BUILT_IN_STPNCPY_CHK: |
0a39fd54 | 486 | case BUILT_IN_STRCAT_CHK: |
487 | case BUILT_IN_STRNCAT_CHK: | |
9373e454 | 488 | case BUILT_IN_ASSUME_ALIGNED: |
75a70cf9 | 489 | if (gimple_call_num_args (call) >= 1) |
490 | return gimple_call_arg (call, 0); | |
0a39fd54 | 491 | break; |
492 | default: | |
493 | break; | |
494 | } | |
495 | ||
496 | return NULL_TREE; | |
497 | } | |
498 | ||
499 | ||
4e91a07b | 500 | /* Compute __builtin_object_size value for PTR and set *PSIZE to |
501 | the resulting value. OBJECT_SIZE_TYPE is the second argument | |
502 | to __builtin_object_size. Return true on success and false | |
503 | when the object size could not be determined. */ | |
0a39fd54 | 504 | |
4e91a07b | 505 | bool |
506 | compute_builtin_object_size (tree ptr, int object_size_type, | |
507 | unsigned HOST_WIDE_INT *psize) | |
0a39fd54 | 508 | { |
509 | gcc_assert (object_size_type >= 0 && object_size_type <= 3); | |
510 | ||
4e91a07b | 511 | /* Set to unknown and overwrite just before returning if the size |
512 | could be determined. */ | |
513 | *psize = unknown[object_size_type]; | |
514 | ||
0a39fd54 | 515 | if (! offset_limit) |
516 | init_offset_limit (); | |
517 | ||
518 | if (TREE_CODE (ptr) == ADDR_EXPR) | |
4e91a07b | 519 | return addr_object_size (NULL, ptr, object_size_type, psize); |
520 | ||
521 | if (TREE_CODE (ptr) != SSA_NAME | |
522 | || !POINTER_TYPE_P (TREE_TYPE (ptr))) | |
523 | return false; | |
0a39fd54 | 524 | |
4e91a07b | 525 | if (computed[object_size_type] == NULL) |
0a39fd54 | 526 | { |
4e91a07b | 527 | if (optimize || object_size_type & 1) |
528 | return false; | |
529 | ||
530 | /* When not optimizing, rather than failing, make a small effort | |
531 | to determine the object size without the full benefit of | |
532 | the (costly) computation below. */ | |
533 | gimple *def = SSA_NAME_DEF_STMT (ptr); | |
534 | if (gimple_code (def) == GIMPLE_ASSIGN) | |
0a39fd54 | 535 | { |
4e91a07b | 536 | tree_code code = gimple_assign_rhs_code (def); |
537 | if (code == POINTER_PLUS_EXPR) | |
0a39fd54 | 538 | { |
4e91a07b | 539 | tree offset = gimple_assign_rhs2 (def); |
540 | ptr = gimple_assign_rhs1 (def); | |
0a39fd54 | 541 | |
17dba507 | 542 | if (tree_fits_shwi_p (offset) |
4e91a07b | 543 | && compute_builtin_object_size (ptr, object_size_type, psize)) |
0a39fd54 | 544 | { |
4e91a07b | 545 | /* Return zero when the offset is out of bounds. */ |
546 | unsigned HOST_WIDE_INT off = tree_to_shwi (offset); | |
547 | *psize = off < *psize ? *psize - off : 0; | |
548 | return true; | |
0a39fd54 | 549 | } |
4e91a07b | 550 | } |
551 | } | |
552 | return false; | |
553 | } | |
0a39fd54 | 554 | |
4e91a07b | 555 | if (!bitmap_bit_p (computed[object_size_type], SSA_NAME_VERSION (ptr))) |
556 | { | |
557 | struct object_size_info osi; | |
558 | bitmap_iterator bi; | |
559 | unsigned int i; | |
560 | ||
561 | if (num_ssa_names > object_sizes[object_size_type].length ()) | |
562 | object_sizes[object_size_type].safe_grow (num_ssa_names); | |
563 | if (dump_file) | |
564 | { | |
565 | fprintf (dump_file, "Computing %s %sobject size for ", | |
566 | (object_size_type & 2) ? "minimum" : "maximum", | |
567 | (object_size_type & 1) ? "sub" : ""); | |
568 | print_generic_expr (dump_file, ptr, dump_flags); | |
569 | fprintf (dump_file, ":\n"); | |
570 | } | |
0a39fd54 | 571 | |
4e91a07b | 572 | osi.visited = BITMAP_ALLOC (NULL); |
573 | osi.reexamine = BITMAP_ALLOC (NULL); | |
574 | osi.object_size_type = object_size_type; | |
575 | osi.depths = NULL; | |
576 | osi.stack = NULL; | |
577 | osi.tos = NULL; | |
578 | ||
579 | /* First pass: walk UD chains, compute object sizes that | |
580 | can be computed. osi.reexamine bitmap at the end will | |
581 | contain what variables were found in dependency cycles | |
582 | and therefore need to be reexamined. */ | |
583 | osi.pass = 0; | |
584 | osi.changed = false; | |
585 | collect_object_sizes_for (&osi, ptr); | |
586 | ||
587 | /* Second pass: keep recomputing object sizes of variables | |
588 | that need reexamination, until no object sizes are | |
589 | increased or all object sizes are computed. */ | |
590 | if (! bitmap_empty_p (osi.reexamine)) | |
591 | { | |
592 | bitmap reexamine = BITMAP_ALLOC (NULL); | |
593 | ||
594 | /* If looking for minimum instead of maximum object size, | |
595 | detect cases where a pointer is increased in a loop. | |
596 | Although even without this detection pass 2 would eventually | |
597 | terminate, it could take a long time. If a pointer is | |
598 | increasing this way, we need to assume 0 object size. | |
599 | E.g. p = &buf[0]; while (cond) p = p + 4; */ | |
600 | if (object_size_type & 2) | |
601 | { | |
602 | osi.depths = XCNEWVEC (unsigned int, num_ssa_names); | |
603 | osi.stack = XNEWVEC (unsigned int, num_ssa_names); | |
604 | osi.tos = osi.stack; | |
605 | osi.pass = 1; | |
606 | /* collect_object_sizes_for is changing | |
607 | osi.reexamine bitmap, so iterate over a copy. */ | |
608 | bitmap_copy (reexamine, osi.reexamine); | |
609 | EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi) | |
610 | if (bitmap_bit_p (osi.reexamine, i)) | |
611 | check_for_plus_in_loops (&osi, ssa_name (i)); | |
612 | ||
613 | free (osi.depths); | |
614 | osi.depths = NULL; | |
615 | free (osi.stack); | |
616 | osi.stack = NULL; | |
617 | osi.tos = NULL; | |
0a39fd54 | 618 | } |
0a39fd54 | 619 | |
4e91a07b | 620 | do |
0a39fd54 | 621 | { |
4e91a07b | 622 | osi.pass = 2; |
623 | osi.changed = false; | |
624 | /* collect_object_sizes_for is changing | |
625 | osi.reexamine bitmap, so iterate over a copy. */ | |
626 | bitmap_copy (reexamine, osi.reexamine); | |
627 | EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi) | |
628 | if (bitmap_bit_p (osi.reexamine, i)) | |
0a39fd54 | 629 | { |
4e91a07b | 630 | collect_object_sizes_for (&osi, ssa_name (i)); |
631 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
632 | { | |
633 | fprintf (dump_file, "Reexamining "); | |
634 | print_generic_expr (dump_file, ssa_name (i), | |
635 | dump_flags); | |
636 | fprintf (dump_file, "\n"); | |
637 | } | |
0a39fd54 | 638 | } |
639 | } | |
4e91a07b | 640 | while (osi.changed); |
0a39fd54 | 641 | |
4e91a07b | 642 | BITMAP_FREE (reexamine); |
0a39fd54 | 643 | } |
4e91a07b | 644 | EXECUTE_IF_SET_IN_BITMAP (osi.reexamine, 0, i, bi) |
645 | bitmap_set_bit (computed[object_size_type], i); | |
0a39fd54 | 646 | |
4e91a07b | 647 | /* Debugging dumps. */ |
648 | if (dump_file) | |
649 | { | |
650 | EXECUTE_IF_SET_IN_BITMAP (osi.visited, 0, i, bi) | |
651 | if (object_sizes[object_size_type][i] | |
652 | != unknown[object_size_type]) | |
653 | { | |
654 | print_generic_expr (dump_file, ssa_name (i), | |
655 | dump_flags); | |
656 | fprintf (dump_file, | |
657 | ": %s %sobject size " | |
658 | HOST_WIDE_INT_PRINT_UNSIGNED "\n", | |
659 | (object_size_type & 2) ? "minimum" : "maximum", | |
660 | (object_size_type & 1) ? "sub" : "", | |
661 | object_sizes[object_size_type][i]); | |
662 | } | |
663 | } | |
664 | ||
665 | BITMAP_FREE (osi.reexamine); | |
666 | BITMAP_FREE (osi.visited); | |
0a39fd54 | 667 | } |
668 | ||
4e91a07b | 669 | *psize = object_sizes[object_size_type][SSA_NAME_VERSION (ptr)]; |
670 | return *psize != unknown[object_size_type]; | |
0a39fd54 | 671 | } |
672 | ||
75a70cf9 | 673 | /* Compute object_sizes for PTR, defined to VALUE, which is not an SSA_NAME. */ |
0a39fd54 | 674 | |
675 | static void | |
676 | expr_object_size (struct object_size_info *osi, tree ptr, tree value) | |
677 | { | |
678 | int object_size_type = osi->object_size_type; | |
679 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
680 | unsigned HOST_WIDE_INT bytes; | |
681 | ||
682 | gcc_assert (object_sizes[object_size_type][varno] | |
683 | != unknown[object_size_type]); | |
684 | gcc_assert (osi->pass == 0); | |
685 | ||
686 | if (TREE_CODE (value) == WITH_SIZE_EXPR) | |
687 | value = TREE_OPERAND (value, 0); | |
688 | ||
689 | /* Pointer variables should have been handled by merge_object_sizes. */ | |
690 | gcc_assert (TREE_CODE (value) != SSA_NAME | |
691 | || !POINTER_TYPE_P (TREE_TYPE (value))); | |
692 | ||
693 | if (TREE_CODE (value) == ADDR_EXPR) | |
4e91a07b | 694 | addr_object_size (osi, value, object_size_type, &bytes); |
0a39fd54 | 695 | else |
696 | bytes = unknown[object_size_type]; | |
697 | ||
698 | if ((object_size_type & 2) == 0) | |
699 | { | |
700 | if (object_sizes[object_size_type][varno] < bytes) | |
701 | object_sizes[object_size_type][varno] = bytes; | |
702 | } | |
703 | else | |
704 | { | |
705 | if (object_sizes[object_size_type][varno] > bytes) | |
706 | object_sizes[object_size_type][varno] = bytes; | |
707 | } | |
708 | } | |
709 | ||
710 | ||
75a70cf9 | 711 | /* Compute object_sizes for PTR, defined to the result of a call. */ |
712 | ||
713 | static void | |
1a91d914 | 714 | call_object_size (struct object_size_info *osi, tree ptr, gcall *call) |
75a70cf9 | 715 | { |
716 | int object_size_type = osi->object_size_type; | |
717 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
718 | unsigned HOST_WIDE_INT bytes; | |
719 | ||
720 | gcc_assert (is_gimple_call (call)); | |
721 | ||
722 | gcc_assert (object_sizes[object_size_type][varno] | |
723 | != unknown[object_size_type]); | |
724 | gcc_assert (osi->pass == 0); | |
725 | ||
726 | bytes = alloc_object_size (call, object_size_type); | |
727 | ||
728 | if ((object_size_type & 2) == 0) | |
729 | { | |
730 | if (object_sizes[object_size_type][varno] < bytes) | |
731 | object_sizes[object_size_type][varno] = bytes; | |
732 | } | |
733 | else | |
734 | { | |
735 | if (object_sizes[object_size_type][varno] > bytes) | |
736 | object_sizes[object_size_type][varno] = bytes; | |
737 | } | |
738 | } | |
739 | ||
740 | ||
741 | /* Compute object_sizes for PTR, defined to an unknown value. */ | |
742 | ||
743 | static void | |
744 | unknown_object_size (struct object_size_info *osi, tree ptr) | |
745 | { | |
746 | int object_size_type = osi->object_size_type; | |
747 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
748 | unsigned HOST_WIDE_INT bytes; | |
749 | ||
750 | gcc_assert (object_sizes[object_size_type][varno] | |
751 | != unknown[object_size_type]); | |
752 | gcc_assert (osi->pass == 0); | |
753 | ||
754 | bytes = unknown[object_size_type]; | |
755 | ||
756 | if ((object_size_type & 2) == 0) | |
757 | { | |
758 | if (object_sizes[object_size_type][varno] < bytes) | |
759 | object_sizes[object_size_type][varno] = bytes; | |
760 | } | |
761 | else | |
762 | { | |
763 | if (object_sizes[object_size_type][varno] > bytes) | |
764 | object_sizes[object_size_type][varno] = bytes; | |
765 | } | |
766 | } | |
767 | ||
768 | ||
0a39fd54 | 769 | /* Merge object sizes of ORIG + OFFSET into DEST. Return true if |
770 | the object size might need reexamination later. */ | |
771 | ||
772 | static bool | |
773 | merge_object_sizes (struct object_size_info *osi, tree dest, tree orig, | |
774 | unsigned HOST_WIDE_INT offset) | |
775 | { | |
776 | int object_size_type = osi->object_size_type; | |
777 | unsigned int varno = SSA_NAME_VERSION (dest); | |
778 | unsigned HOST_WIDE_INT orig_bytes; | |
779 | ||
780 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
781 | return false; | |
782 | if (offset >= offset_limit) | |
783 | { | |
784 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
785 | return false; | |
786 | } | |
787 | ||
788 | if (osi->pass == 0) | |
789 | collect_object_sizes_for (osi, orig); | |
790 | ||
791 | orig_bytes = object_sizes[object_size_type][SSA_NAME_VERSION (orig)]; | |
792 | if (orig_bytes != unknown[object_size_type]) | |
793 | orig_bytes = (offset > orig_bytes) | |
457daa4e | 794 | ? HOST_WIDE_INT_0U : orig_bytes - offset; |
0a39fd54 | 795 | |
796 | if ((object_size_type & 2) == 0) | |
797 | { | |
798 | if (object_sizes[object_size_type][varno] < orig_bytes) | |
799 | { | |
800 | object_sizes[object_size_type][varno] = orig_bytes; | |
801 | osi->changed = true; | |
802 | } | |
803 | } | |
804 | else | |
805 | { | |
806 | if (object_sizes[object_size_type][varno] > orig_bytes) | |
807 | { | |
808 | object_sizes[object_size_type][varno] = orig_bytes; | |
809 | osi->changed = true; | |
810 | } | |
811 | } | |
812 | return bitmap_bit_p (osi->reexamine, SSA_NAME_VERSION (orig)); | |
813 | } | |
814 | ||
815 | ||
75a70cf9 | 816 | /* Compute object_sizes for VAR, defined to the result of an assignment |
817 | with operator POINTER_PLUS_EXPR. Return true if the object size might | |
818 | need reexamination later. */ | |
0a39fd54 | 819 | |
820 | static bool | |
42acab1c | 821 | plus_stmt_object_size (struct object_size_info *osi, tree var, gimple *stmt) |
0a39fd54 | 822 | { |
0a39fd54 | 823 | int object_size_type = osi->object_size_type; |
824 | unsigned int varno = SSA_NAME_VERSION (var); | |
825 | unsigned HOST_WIDE_INT bytes; | |
75a70cf9 | 826 | tree op0, op1; |
827 | ||
182cf5a9 | 828 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) |
829 | { | |
830 | op0 = gimple_assign_rhs1 (stmt); | |
831 | op1 = gimple_assign_rhs2 (stmt); | |
832 | } | |
833 | else if (gimple_assign_rhs_code (stmt) == ADDR_EXPR) | |
834 | { | |
835 | tree rhs = TREE_OPERAND (gimple_assign_rhs1 (stmt), 0); | |
836 | gcc_assert (TREE_CODE (rhs) == MEM_REF); | |
837 | op0 = TREE_OPERAND (rhs, 0); | |
838 | op1 = TREE_OPERAND (rhs, 1); | |
839 | } | |
840 | else | |
841 | gcc_unreachable (); | |
0a39fd54 | 842 | |
843 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
844 | return false; | |
845 | ||
0a39fd54 | 846 | /* Handle PTR + OFFSET here. */ |
0de36bdb | 847 | if (TREE_CODE (op1) == INTEGER_CST |
0a39fd54 | 848 | && (TREE_CODE (op0) == SSA_NAME |
849 | || TREE_CODE (op0) == ADDR_EXPR)) | |
850 | { | |
e913b5cd | 851 | if (! tree_fits_uhwi_p (op1)) |
0a39fd54 | 852 | bytes = unknown[object_size_type]; |
853 | else if (TREE_CODE (op0) == SSA_NAME) | |
e913b5cd | 854 | return merge_object_sizes (osi, var, op0, tree_to_uhwi (op1)); |
0a39fd54 | 855 | else |
856 | { | |
e913b5cd | 857 | unsigned HOST_WIDE_INT off = tree_to_uhwi (op1); |
0a39fd54 | 858 | |
75a70cf9 | 859 | /* op0 will be ADDR_EXPR here. */ |
4e91a07b | 860 | addr_object_size (osi, op0, object_size_type, &bytes); |
06f9fe3e | 861 | if (bytes == unknown[object_size_type]) |
862 | ; | |
863 | else if (off > offset_limit) | |
0a39fd54 | 864 | bytes = unknown[object_size_type]; |
865 | else if (off > bytes) | |
866 | bytes = 0; | |
867 | else | |
868 | bytes -= off; | |
869 | } | |
870 | } | |
871 | else | |
872 | bytes = unknown[object_size_type]; | |
873 | ||
874 | if ((object_size_type & 2) == 0) | |
875 | { | |
876 | if (object_sizes[object_size_type][varno] < bytes) | |
877 | object_sizes[object_size_type][varno] = bytes; | |
878 | } | |
879 | else | |
880 | { | |
881 | if (object_sizes[object_size_type][varno] > bytes) | |
882 | object_sizes[object_size_type][varno] = bytes; | |
883 | } | |
884 | return false; | |
885 | } | |
886 | ||
887 | ||
8a2caf10 | 888 | /* Compute object_sizes for VAR, defined at STMT, which is |
ec0fa513 | 889 | a COND_EXPR. Return true if the object size might need reexamination |
890 | later. */ | |
891 | ||
892 | static bool | |
42acab1c | 893 | cond_expr_object_size (struct object_size_info *osi, tree var, gimple *stmt) |
ec0fa513 | 894 | { |
895 | tree then_, else_; | |
896 | int object_size_type = osi->object_size_type; | |
897 | unsigned int varno = SSA_NAME_VERSION (var); | |
898 | bool reexamine = false; | |
899 | ||
8a2caf10 | 900 | gcc_assert (gimple_assign_rhs_code (stmt) == COND_EXPR); |
ec0fa513 | 901 | |
902 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
903 | return false; | |
904 | ||
8a2caf10 | 905 | then_ = gimple_assign_rhs2 (stmt); |
906 | else_ = gimple_assign_rhs3 (stmt); | |
ec0fa513 | 907 | |
908 | if (TREE_CODE (then_) == SSA_NAME) | |
909 | reexamine |= merge_object_sizes (osi, var, then_, 0); | |
910 | else | |
911 | expr_object_size (osi, var, then_); | |
912 | ||
913 | if (TREE_CODE (else_) == SSA_NAME) | |
914 | reexamine |= merge_object_sizes (osi, var, else_, 0); | |
915 | else | |
916 | expr_object_size (osi, var, else_); | |
917 | ||
918 | return reexamine; | |
919 | } | |
920 | ||
0a39fd54 | 921 | /* Compute object sizes for VAR. |
922 | For ADDR_EXPR an object size is the number of remaining bytes | |
56d36a49 | 923 | to the end of the object (where what is considered an object depends on |
0a39fd54 | 924 | OSI->object_size_type). |
75a70cf9 | 925 | For allocation GIMPLE_CALL like malloc or calloc object size is the size |
0a39fd54 | 926 | of the allocation. |
0de36bdb | 927 | For POINTER_PLUS_EXPR where second operand is a constant integer, |
0a39fd54 | 928 | object size is object size of the first operand minus the constant. |
929 | If the constant is bigger than the number of remaining bytes until the | |
930 | end of the object, object size is 0, but if it is instead a pointer | |
931 | subtraction, object size is unknown[object_size_type]. | |
932 | To differentiate addition from subtraction, ADDR_EXPR returns | |
933 | unknown[object_size_type] for all objects bigger than half of the address | |
934 | space, and constants less than half of the address space are considered | |
935 | addition, while bigger constants subtraction. | |
75a70cf9 | 936 | For a memcpy like GIMPLE_CALL that always returns one of its arguments, the |
0a39fd54 | 937 | object size is object size of that argument. |
938 | Otherwise, object size is the maximum of object sizes of variables | |
939 | that it might be set to. */ | |
940 | ||
941 | static void | |
942 | collect_object_sizes_for (struct object_size_info *osi, tree var) | |
943 | { | |
944 | int object_size_type = osi->object_size_type; | |
945 | unsigned int varno = SSA_NAME_VERSION (var); | |
42acab1c | 946 | gimple *stmt; |
0a39fd54 | 947 | bool reexamine; |
948 | ||
949 | if (bitmap_bit_p (computed[object_size_type], varno)) | |
950 | return; | |
951 | ||
952 | if (osi->pass == 0) | |
953 | { | |
6ef9bbe0 | 954 | if (bitmap_set_bit (osi->visited, varno)) |
0a39fd54 | 955 | { |
0a39fd54 | 956 | object_sizes[object_size_type][varno] |
957 | = (object_size_type & 2) ? -1 : 0; | |
958 | } | |
959 | else | |
960 | { | |
961 | /* Found a dependency loop. Mark the variable for later | |
962 | re-examination. */ | |
963 | bitmap_set_bit (osi->reexamine, varno); | |
964 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
965 | { | |
966 | fprintf (dump_file, "Found a dependency loop at "); | |
967 | print_generic_expr (dump_file, var, dump_flags); | |
968 | fprintf (dump_file, "\n"); | |
969 | } | |
970 | return; | |
971 | } | |
972 | } | |
973 | ||
974 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
975 | { | |
976 | fprintf (dump_file, "Visiting use-def links for "); | |
977 | print_generic_expr (dump_file, var, dump_flags); | |
978 | fprintf (dump_file, "\n"); | |
979 | } | |
980 | ||
981 | stmt = SSA_NAME_DEF_STMT (var); | |
982 | reexamine = false; | |
983 | ||
75a70cf9 | 984 | switch (gimple_code (stmt)) |
0a39fd54 | 985 | { |
75a70cf9 | 986 | case GIMPLE_ASSIGN: |
0a39fd54 | 987 | { |
182cf5a9 | 988 | tree rhs = gimple_assign_rhs1 (stmt); |
989 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR | |
990 | || (gimple_assign_rhs_code (stmt) == ADDR_EXPR | |
991 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == MEM_REF)) | |
75a70cf9 | 992 | reexamine = plus_stmt_object_size (osi, var, stmt); |
8a2caf10 | 993 | else if (gimple_assign_rhs_code (stmt) == COND_EXPR) |
994 | reexamine = cond_expr_object_size (osi, var, stmt); | |
75a70cf9 | 995 | else if (gimple_assign_single_p (stmt) |
996 | || gimple_assign_unary_nop_p (stmt)) | |
997 | { | |
75a70cf9 | 998 | if (TREE_CODE (rhs) == SSA_NAME |
999 | && POINTER_TYPE_P (TREE_TYPE (rhs))) | |
1000 | reexamine = merge_object_sizes (osi, var, rhs, 0); | |
75a70cf9 | 1001 | else |
1002 | expr_object_size (osi, var, rhs); | |
1003 | } | |
1004 | else | |
1005 | unknown_object_size (osi, var); | |
1006 | break; | |
1007 | } | |
ec0fa513 | 1008 | |
75a70cf9 | 1009 | case GIMPLE_CALL: |
1010 | { | |
1a91d914 | 1011 | gcall *call_stmt = as_a <gcall *> (stmt); |
1012 | tree arg = pass_through_call (call_stmt); | |
75a70cf9 | 1013 | if (arg) |
1014 | { | |
1015 | if (TREE_CODE (arg) == SSA_NAME | |
1016 | && POINTER_TYPE_P (TREE_TYPE (arg))) | |
1017 | reexamine = merge_object_sizes (osi, var, arg, 0); | |
75a70cf9 | 1018 | else |
1019 | expr_object_size (osi, var, arg); | |
1020 | } | |
1021 | else | |
1a91d914 | 1022 | call_object_size (osi, var, call_stmt); |
0a39fd54 | 1023 | break; |
1024 | } | |
1025 | ||
75a70cf9 | 1026 | case GIMPLE_ASM: |
0a39fd54 | 1027 | /* Pointers defined by __asm__ statements can point anywhere. */ |
1028 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
1029 | break; | |
1030 | ||
75a70cf9 | 1031 | case GIMPLE_NOP: |
ec11736b | 1032 | if (SSA_NAME_VAR (var) |
1033 | && TREE_CODE (SSA_NAME_VAR (var)) == PARM_DECL) | |
1034 | expr_object_size (osi, var, SSA_NAME_VAR (var)); | |
1035 | else | |
1036 | /* Uninitialized SSA names point nowhere. */ | |
1037 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
0a39fd54 | 1038 | break; |
1039 | ||
75a70cf9 | 1040 | case GIMPLE_PHI: |
0a39fd54 | 1041 | { |
75a70cf9 | 1042 | unsigned i; |
0a39fd54 | 1043 | |
75a70cf9 | 1044 | for (i = 0; i < gimple_phi_num_args (stmt); i++) |
0a39fd54 | 1045 | { |
75a70cf9 | 1046 | tree rhs = gimple_phi_arg (stmt, i)->def; |
0a39fd54 | 1047 | |
1048 | if (object_sizes[object_size_type][varno] | |
1049 | == unknown[object_size_type]) | |
1050 | break; | |
1051 | ||
1052 | if (TREE_CODE (rhs) == SSA_NAME) | |
1053 | reexamine |= merge_object_sizes (osi, var, rhs, 0); | |
1054 | else if (osi->pass == 0) | |
1055 | expr_object_size (osi, var, rhs); | |
1056 | } | |
1057 | break; | |
1058 | } | |
75a70cf9 | 1059 | |
0a39fd54 | 1060 | default: |
1061 | gcc_unreachable (); | |
1062 | } | |
1063 | ||
1064 | if (! reexamine | |
1065 | || object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
1066 | { | |
1067 | bitmap_set_bit (computed[object_size_type], varno); | |
1068 | bitmap_clear_bit (osi->reexamine, varno); | |
1069 | } | |
1070 | else | |
1071 | { | |
1072 | bitmap_set_bit (osi->reexamine, varno); | |
1073 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1074 | { | |
1075 | fprintf (dump_file, "Need to reexamine "); | |
1076 | print_generic_expr (dump_file, var, dump_flags); | |
1077 | fprintf (dump_file, "\n"); | |
1078 | } | |
1079 | } | |
1080 | } | |
1081 | ||
1082 | ||
1083 | /* Helper function for check_for_plus_in_loops. Called recursively | |
1084 | to detect loops. */ | |
1085 | ||
1086 | static void | |
1087 | check_for_plus_in_loops_1 (struct object_size_info *osi, tree var, | |
1088 | unsigned int depth) | |
1089 | { | |
42acab1c | 1090 | gimple *stmt = SSA_NAME_DEF_STMT (var); |
0a39fd54 | 1091 | unsigned int varno = SSA_NAME_VERSION (var); |
1092 | ||
1093 | if (osi->depths[varno]) | |
1094 | { | |
1095 | if (osi->depths[varno] != depth) | |
1096 | { | |
1097 | unsigned int *sp; | |
1098 | ||
1099 | /* Found a loop involving pointer addition. */ | |
1100 | for (sp = osi->tos; sp > osi->stack; ) | |
1101 | { | |
1102 | --sp; | |
1103 | bitmap_clear_bit (osi->reexamine, *sp); | |
1104 | bitmap_set_bit (computed[osi->object_size_type], *sp); | |
1105 | object_sizes[osi->object_size_type][*sp] = 0; | |
1106 | if (*sp == varno) | |
1107 | break; | |
1108 | } | |
1109 | } | |
1110 | return; | |
1111 | } | |
1112 | else if (! bitmap_bit_p (osi->reexamine, varno)) | |
1113 | return; | |
1114 | ||
1115 | osi->depths[varno] = depth; | |
1116 | *osi->tos++ = varno; | |
1117 | ||
75a70cf9 | 1118 | switch (gimple_code (stmt)) |
0a39fd54 | 1119 | { |
0a39fd54 | 1120 | |
75a70cf9 | 1121 | case GIMPLE_ASSIGN: |
0a39fd54 | 1122 | { |
75a70cf9 | 1123 | if ((gimple_assign_single_p (stmt) |
1124 | || gimple_assign_unary_nop_p (stmt)) | |
1125 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
1126 | { | |
1127 | tree rhs = gimple_assign_rhs1 (stmt); | |
1128 | ||
1129 | check_for_plus_in_loops_1 (osi, rhs, depth); | |
1130 | } | |
1131 | else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) | |
1132 | { | |
1133 | tree basevar = gimple_assign_rhs1 (stmt); | |
1134 | tree cst = gimple_assign_rhs2 (stmt); | |
1135 | ||
1136 | gcc_assert (TREE_CODE (cst) == INTEGER_CST); | |
1137 | ||
1138 | check_for_plus_in_loops_1 (osi, basevar, | |
1139 | depth + !integer_zerop (cst)); | |
1140 | } | |
1141 | else | |
1142 | gcc_unreachable (); | |
1143 | break; | |
1144 | } | |
0a39fd54 | 1145 | |
75a70cf9 | 1146 | case GIMPLE_CALL: |
1147 | { | |
1a91d914 | 1148 | gcall *call_stmt = as_a <gcall *> (stmt); |
1149 | tree arg = pass_through_call (call_stmt); | |
75a70cf9 | 1150 | if (arg) |
1151 | { | |
1152 | if (TREE_CODE (arg) == SSA_NAME) | |
1153 | check_for_plus_in_loops_1 (osi, arg, depth); | |
1154 | else | |
1155 | gcc_unreachable (); | |
1156 | } | |
1157 | break; | |
0a39fd54 | 1158 | } |
75a70cf9 | 1159 | |
1160 | case GIMPLE_PHI: | |
0a39fd54 | 1161 | { |
75a70cf9 | 1162 | unsigned i; |
0a39fd54 | 1163 | |
75a70cf9 | 1164 | for (i = 0; i < gimple_phi_num_args (stmt); i++) |
0a39fd54 | 1165 | { |
75a70cf9 | 1166 | tree rhs = gimple_phi_arg (stmt, i)->def; |
0a39fd54 | 1167 | |
1168 | if (TREE_CODE (rhs) == SSA_NAME) | |
1169 | check_for_plus_in_loops_1 (osi, rhs, depth); | |
1170 | } | |
1171 | break; | |
1172 | } | |
75a70cf9 | 1173 | |
0a39fd54 | 1174 | default: |
1175 | gcc_unreachable (); | |
1176 | } | |
1177 | ||
1178 | osi->depths[varno] = 0; | |
1179 | osi->tos--; | |
1180 | } | |
1181 | ||
1182 | ||
1183 | /* Check if some pointer we are computing object size of is being increased | |
1184 | within a loop. If yes, assume all the SSA variables participating in | |
1185 | that loop have minimum object sizes 0. */ | |
1186 | ||
1187 | static void | |
1188 | check_for_plus_in_loops (struct object_size_info *osi, tree var) | |
1189 | { | |
42acab1c | 1190 | gimple *stmt = SSA_NAME_DEF_STMT (var); |
0a39fd54 | 1191 | |
75a70cf9 | 1192 | /* NOTE: In the pre-tuples code, we handled a CALL_EXPR here, |
1193 | and looked for a POINTER_PLUS_EXPR in the pass-through | |
1194 | argument, if any. In GIMPLE, however, such an expression | |
1195 | is not a valid call operand. */ | |
0a39fd54 | 1196 | |
75a70cf9 | 1197 | if (is_gimple_assign (stmt) |
1198 | && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) | |
1199 | { | |
1200 | tree basevar = gimple_assign_rhs1 (stmt); | |
1201 | tree cst = gimple_assign_rhs2 (stmt); | |
48e1416a | 1202 | |
75a70cf9 | 1203 | gcc_assert (TREE_CODE (cst) == INTEGER_CST); |
1204 | ||
1205 | if (integer_zerop (cst)) | |
1206 | return; | |
1207 | ||
1208 | osi->depths[SSA_NAME_VERSION (basevar)] = 1; | |
1209 | *osi->tos++ = SSA_NAME_VERSION (basevar); | |
1210 | check_for_plus_in_loops_1 (osi, var, 2); | |
1211 | osi->depths[SSA_NAME_VERSION (basevar)] = 0; | |
1212 | osi->tos--; | |
0a39fd54 | 1213 | } |
1214 | } | |
1215 | ||
1216 | ||
1217 | /* Initialize data structures for the object size computation. */ | |
1218 | ||
1219 | void | |
1220 | init_object_sizes (void) | |
1221 | { | |
1222 | int object_size_type; | |
1223 | ||
194eb161 | 1224 | if (computed[0]) |
0a39fd54 | 1225 | return; |
1226 | ||
1227 | for (object_size_type = 0; object_size_type <= 3; object_size_type++) | |
1228 | { | |
194eb161 | 1229 | object_sizes[object_size_type].safe_grow (num_ssa_names); |
0a39fd54 | 1230 | computed[object_size_type] = BITMAP_ALLOC (NULL); |
1231 | } | |
1232 | ||
1233 | init_offset_limit (); | |
1234 | } | |
1235 | ||
1236 | ||
1237 | /* Destroy data structures after the object size computation. */ | |
1238 | ||
d17f89dd | 1239 | void |
0a39fd54 | 1240 | fini_object_sizes (void) |
1241 | { | |
1242 | int object_size_type; | |
1243 | ||
1244 | for (object_size_type = 0; object_size_type <= 3; object_size_type++) | |
1245 | { | |
194eb161 | 1246 | object_sizes[object_size_type].release (); |
0a39fd54 | 1247 | BITMAP_FREE (computed[object_size_type]); |
0a39fd54 | 1248 | } |
1249 | } | |
1250 | ||
1251 | ||
1252 | /* Simple pass to optimize all __builtin_object_size () builtins. */ | |
1253 | ||
65b0537f | 1254 | namespace { |
1255 | ||
1256 | const pass_data pass_data_object_sizes = | |
1257 | { | |
1258 | GIMPLE_PASS, /* type */ | |
1259 | "objsz", /* name */ | |
1260 | OPTGROUP_NONE, /* optinfo_flags */ | |
65b0537f | 1261 | TV_NONE, /* tv_id */ |
1262 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1263 | 0, /* properties_provided */ | |
1264 | 0, /* properties_destroyed */ | |
1265 | 0, /* todo_flags_start */ | |
8b88439e | 1266 | 0, /* todo_flags_finish */ |
65b0537f | 1267 | }; |
1268 | ||
1269 | class pass_object_sizes : public gimple_opt_pass | |
1270 | { | |
1271 | public: | |
1272 | pass_object_sizes (gcc::context *ctxt) | |
0bb8a43b | 1273 | : gimple_opt_pass (pass_data_object_sizes, ctxt), insert_min_max_p (false) |
65b0537f | 1274 | {} |
1275 | ||
1276 | /* opt_pass methods: */ | |
1277 | opt_pass * clone () { return new pass_object_sizes (m_ctxt); } | |
0bb8a43b | 1278 | void set_pass_param (unsigned int n, bool param) |
1279 | { | |
1280 | gcc_assert (n == 0); | |
1281 | insert_min_max_p = param; | |
1282 | } | |
65b0537f | 1283 | virtual unsigned int execute (function *); |
1284 | ||
0bb8a43b | 1285 | private: |
1286 | /* Determines whether the pass instance creates MIN/MAX_EXPRs. */ | |
1287 | bool insert_min_max_p; | |
65b0537f | 1288 | }; // class pass_object_sizes |
1289 | ||
1603b4dc | 1290 | /* Dummy valueize function. */ |
1291 | ||
1292 | static tree | |
1293 | do_valueize (tree t) | |
1294 | { | |
1295 | return t; | |
1296 | } | |
1297 | ||
65b0537f | 1298 | unsigned int |
1299 | pass_object_sizes::execute (function *fun) | |
0a39fd54 | 1300 | { |
1301 | basic_block bb; | |
65b0537f | 1302 | FOR_EACH_BB_FN (bb, fun) |
0a39fd54 | 1303 | { |
75a70cf9 | 1304 | gimple_stmt_iterator i; |
1305 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) | |
0a39fd54 | 1306 | { |
6a00bf6b | 1307 | tree result; |
42acab1c | 1308 | gimple *call = gsi_stmt (i); |
6a00bf6b | 1309 | if (!gimple_call_builtin_p (call, BUILT_IN_OBJECT_SIZE)) |
0a39fd54 | 1310 | continue; |
1311 | ||
1312 | init_object_sizes (); | |
ece434d4 | 1313 | |
0bb8a43b | 1314 | /* If insert_min_max_p, only attempt to fold |
ece434d4 | 1315 | __builtin_object_size (x, 1) and __builtin_object_size (x, 3), |
1316 | and rather than folding the builtin to the constant if any, | |
1317 | create a MIN_EXPR or MAX_EXPR of the __builtin_object_size | |
1318 | call result and the computed constant. */ | |
0bb8a43b | 1319 | if (insert_min_max_p) |
ece434d4 | 1320 | { |
1321 | tree ost = gimple_call_arg (call, 1); | |
1322 | if (tree_fits_uhwi_p (ost)) | |
1323 | { | |
1324 | unsigned HOST_WIDE_INT object_size_type = tree_to_uhwi (ost); | |
1325 | tree ptr = gimple_call_arg (call, 0); | |
1326 | tree lhs = gimple_call_lhs (call); | |
1327 | if ((object_size_type == 1 || object_size_type == 3) | |
1328 | && (TREE_CODE (ptr) == ADDR_EXPR | |
1329 | || TREE_CODE (ptr) == SSA_NAME) | |
1330 | && lhs) | |
1331 | { | |
1332 | tree type = TREE_TYPE (lhs); | |
4e91a07b | 1333 | unsigned HOST_WIDE_INT bytes; |
1334 | if (compute_builtin_object_size (ptr, object_size_type, | |
1335 | &bytes) | |
ece434d4 | 1336 | && wi::fits_to_tree_p (bytes, type)) |
1337 | { | |
1338 | tree tem = make_ssa_name (type); | |
1339 | gimple_call_set_lhs (call, tem); | |
1340 | enum tree_code code | |
1341 | = object_size_type == 1 ? MIN_EXPR : MAX_EXPR; | |
1342 | tree cst = build_int_cstu (type, bytes); | |
42acab1c | 1343 | gimple *g |
1344 | = gimple_build_assign (lhs, code, tem, cst); | |
ece434d4 | 1345 | gsi_insert_after (&i, g, GSI_NEW_STMT); |
1346 | update_stmt (call); | |
1347 | } | |
1348 | } | |
1349 | } | |
1350 | continue; | |
1351 | } | |
1352 | ||
1603b4dc | 1353 | tree lhs = gimple_call_lhs (call); |
1354 | if (!lhs) | |
1355 | continue; | |
1356 | ||
1357 | result = gimple_fold_stmt_to_constant (call, do_valueize); | |
0a39fd54 | 1358 | if (!result) |
1359 | { | |
ece434d4 | 1360 | tree ost = gimple_call_arg (call, 1); |
1361 | ||
1362 | if (tree_fits_uhwi_p (ost)) | |
0a39fd54 | 1363 | { |
ece434d4 | 1364 | unsigned HOST_WIDE_INT object_size_type = tree_to_uhwi (ost); |
0a39fd54 | 1365 | |
ece434d4 | 1366 | if (object_size_type < 2) |
1367 | result = fold_convert (size_type_node, | |
1368 | integer_minus_one_node); | |
1369 | else if (object_size_type < 4) | |
1370 | result = build_zero_cst (size_type_node); | |
0a39fd54 | 1371 | } |
1372 | ||
1373 | if (!result) | |
1374 | continue; | |
1375 | } | |
1376 | ||
6a00bf6b | 1377 | gcc_assert (TREE_CODE (result) == INTEGER_CST); |
1378 | ||
0a39fd54 | 1379 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1380 | { | |
1381 | fprintf (dump_file, "Simplified\n "); | |
75a70cf9 | 1382 | print_gimple_stmt (dump_file, call, 0, dump_flags); |
6a00bf6b | 1383 | fprintf (dump_file, " to "); |
1ffa4346 | 1384 | print_generic_expr (dump_file, result); |
6a00bf6b | 1385 | fprintf (dump_file, "\n"); |
0a39fd54 | 1386 | } |
1387 | ||
6a00bf6b | 1388 | /* Propagate into all uses and fold those stmts. */ |
1603b4dc | 1389 | replace_uses_by (lhs, result); |
0a39fd54 | 1390 | } |
1391 | } | |
1392 | ||
1393 | fini_object_sizes (); | |
2a1990e9 | 1394 | return 0; |
0a39fd54 | 1395 | } |
1396 | ||
cbe8bda8 | 1397 | } // anon namespace |
1398 | ||
1399 | gimple_opt_pass * | |
1400 | make_pass_object_sizes (gcc::context *ctxt) | |
1401 | { | |
1402 | return new pass_object_sizes (ctxt); | |
1403 | } |