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0a39fd54 | 1 | /* __builtin_object_size (ptr, object_size_type) computation |
fbd26352 | 2 | Copyright (C) 2004-2019 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 *, |
2beadd91 | 57 | const_tree, int, unsigned HOST_WIDE_INT *, |
58 | tree * = NULL); | |
1a91d914 | 59 | static unsigned HOST_WIDE_INT alloc_object_size (const gcall *, int); |
60 | static tree pass_through_call (const gcall *); | |
0a39fd54 | 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); | |
24500bba | 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 *); | |
0a39fd54 | 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. */ | |
194eb161 | 78 | static vec<unsigned HOST_WIDE_INT> object_sizes[4]; |
0a39fd54 | 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 | { | |
e913b5cd | 91 | if (tree_fits_uhwi_p (TYPE_MAX_VALUE (sizetype))) |
92 | offset_limit = tree_to_uhwi (TYPE_MAX_VALUE (sizetype)); | |
0a39fd54 | 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 | |
b4b34335 | 103 | compute_object_offset (const_tree expr, const_tree var) |
0a39fd54 | 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), | |
e913b5cd | 120 | size_int (tree_to_uhwi (DECL_FIELD_BIT_OFFSET (t)) |
0a39fd54 | 121 | / BITS_PER_UNIT)); |
122 | break; | |
123 | ||
124 | case REALPART_EXPR: | |
72dd6141 | 125 | CASE_CONVERT: |
0a39fd54 | 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); | |
30a04590 | 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); | |
0a39fd54 | 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 | } | |
535664e3 | 154 | t = fold_convert (sizetype, t); |
30a04590 | 155 | off = size_binop (MULT_EXPR, unit_size, t); |
0a39fd54 | 156 | break; |
157 | ||
182cf5a9 | 158 | case MEM_REF: |
159 | gcc_assert (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR); | |
e913b5cd | 160 | return wide_int_to_tree (sizetype, mem_ref_offset (expr)); |
182cf5a9 | 161 | |
0a39fd54 | 162 | default: |
163 | return error_mark_node; | |
164 | } | |
165 | ||
166 | return size_binop (code, base, off); | |
167 | } | |
168 | ||
169 | ||
170 | /* Compute __builtin_object_size for PTR, which is a ADDR_EXPR. | |
171 | OBJECT_SIZE_TYPE is the second argument from __builtin_object_size. | |
172 | If unknown, return unknown[object_size_type]. */ | |
173 | ||
4e91a07b | 174 | static bool |
fbc1ccbc | 175 | addr_object_size (struct object_size_info *osi, const_tree ptr, |
2beadd91 | 176 | int object_size_type, unsigned HOST_WIDE_INT *psize, |
177 | tree *pdecl /* = NULL */) | |
0a39fd54 | 178 | { |
fbc1ccbc | 179 | tree pt_var, pt_var_size = NULL_TREE, var_size, bytes; |
0a39fd54 | 180 | |
2beadd91 | 181 | tree dummy; |
182 | if (!pdecl) | |
183 | pdecl = &dummy; | |
184 | ||
0a39fd54 | 185 | gcc_assert (TREE_CODE (ptr) == ADDR_EXPR); |
186 | ||
4e91a07b | 187 | /* Set to unknown and overwrite just before returning if the size |
188 | could be determined. */ | |
189 | *psize = unknown[object_size_type]; | |
190 | ||
0a39fd54 | 191 | pt_var = TREE_OPERAND (ptr, 0); |
97a7a862 | 192 | while (handled_component_p (pt_var)) |
193 | pt_var = TREE_OPERAND (pt_var, 0); | |
0a39fd54 | 194 | |
195 | if (pt_var | |
97a7a862 | 196 | && TREE_CODE (pt_var) == MEM_REF) |
0a39fd54 | 197 | { |
fbc1ccbc | 198 | unsigned HOST_WIDE_INT sz; |
0a39fd54 | 199 | |
97a7a862 | 200 | if (!osi || (object_size_type & 1) != 0 |
cd45d8fd | 201 | || TREE_CODE (TREE_OPERAND (pt_var, 0)) != SSA_NAME) |
182cf5a9 | 202 | { |
4e91a07b | 203 | compute_builtin_object_size (TREE_OPERAND (pt_var, 0), |
2beadd91 | 204 | object_size_type & ~1, &sz, pdecl); |
182cf5a9 | 205 | } |
fbc1ccbc | 206 | else |
0a39fd54 | 207 | { |
fbc1ccbc | 208 | tree var = TREE_OPERAND (pt_var, 0); |
209 | if (osi->pass == 0) | |
210 | collect_object_sizes_for (osi, var); | |
211 | if (bitmap_bit_p (computed[object_size_type], | |
212 | SSA_NAME_VERSION (var))) | |
213 | sz = object_sizes[object_size_type][SSA_NAME_VERSION (var)]; | |
214 | else | |
215 | sz = unknown[object_size_type]; | |
97a7a862 | 216 | } |
217 | if (sz != unknown[object_size_type]) | |
218 | { | |
90ca1268 | 219 | offset_int mem_offset; |
220 | if (mem_ref_offset (pt_var).is_constant (&mem_offset)) | |
221 | { | |
222 | offset_int dsz = wi::sub (sz, mem_offset); | |
223 | if (wi::neg_p (dsz)) | |
224 | sz = 0; | |
225 | else if (wi::fits_uhwi_p (dsz)) | |
226 | sz = dsz.to_uhwi (); | |
227 | else | |
228 | sz = unknown[object_size_type]; | |
229 | } | |
182cf5a9 | 230 | else |
97a7a862 | 231 | sz = unknown[object_size_type]; |
fbc1ccbc | 232 | } |
233 | ||
234 | if (sz != unknown[object_size_type] && sz < offset_limit) | |
235 | pt_var_size = size_int (sz); | |
236 | } | |
dda02ea2 | 237 | else if (pt_var |
238 | && DECL_P (pt_var) | |
e913b5cd | 239 | && tree_fits_uhwi_p (DECL_SIZE_UNIT (pt_var)) |
aa59f000 | 240 | && tree_to_uhwi (DECL_SIZE_UNIT (pt_var)) < offset_limit) |
2beadd91 | 241 | { |
242 | *pdecl = pt_var; | |
243 | pt_var_size = DECL_SIZE_UNIT (pt_var); | |
244 | } | |
fbc1ccbc | 245 | else if (pt_var |
97a7a862 | 246 | && TREE_CODE (pt_var) == STRING_CST |
fbc1ccbc | 247 | && TYPE_SIZE_UNIT (TREE_TYPE (pt_var)) |
e913b5cd | 248 | && tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (pt_var))) |
aa59f000 | 249 | && tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (pt_var))) |
fbc1ccbc | 250 | < offset_limit) |
251 | pt_var_size = TYPE_SIZE_UNIT (TREE_TYPE (pt_var)); | |
252 | else | |
4e91a07b | 253 | return false; |
fbc1ccbc | 254 | |
255 | if (pt_var != TREE_OPERAND (ptr, 0)) | |
256 | { | |
257 | tree var; | |
0a39fd54 | 258 | |
fbc1ccbc | 259 | if (object_size_type & 1) |
260 | { | |
261 | var = TREE_OPERAND (ptr, 0); | |
262 | ||
263 | while (var != pt_var | |
264 | && TREE_CODE (var) != BIT_FIELD_REF | |
265 | && TREE_CODE (var) != COMPONENT_REF | |
266 | && TREE_CODE (var) != ARRAY_REF | |
267 | && TREE_CODE (var) != ARRAY_RANGE_REF | |
268 | && TREE_CODE (var) != REALPART_EXPR | |
269 | && TREE_CODE (var) != IMAGPART_EXPR) | |
270 | var = TREE_OPERAND (var, 0); | |
271 | if (var != pt_var && TREE_CODE (var) == ARRAY_REF) | |
ffbeca59 | 272 | var = TREE_OPERAND (var, 0); |
fbc1ccbc | 273 | if (! TYPE_SIZE_UNIT (TREE_TYPE (var)) |
e913b5cd | 274 | || ! tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (var))) |
fbc1ccbc | 275 | || (pt_var_size |
276 | && tree_int_cst_lt (pt_var_size, | |
277 | TYPE_SIZE_UNIT (TREE_TYPE (var))))) | |
278 | var = pt_var; | |
182cf5a9 | 279 | else if (var != pt_var && TREE_CODE (pt_var) == MEM_REF) |
0a39fd54 | 280 | { |
fbc1ccbc | 281 | tree v = var; |
282 | /* For &X->fld, compute object size only if fld isn't the last | |
283 | field, as struct { int i; char c[1]; } is often used instead | |
284 | of flexible array member. */ | |
285 | while (v && v != pt_var) | |
286 | switch (TREE_CODE (v)) | |
287 | { | |
288 | case ARRAY_REF: | |
289 | if (TYPE_SIZE_UNIT (TREE_TYPE (TREE_OPERAND (v, 0))) | |
290 | && TREE_CODE (TREE_OPERAND (v, 1)) == INTEGER_CST) | |
291 | { | |
292 | tree domain | |
293 | = TYPE_DOMAIN (TREE_TYPE (TREE_OPERAND (v, 0))); | |
294 | if (domain | |
295 | && TYPE_MAX_VALUE (domain) | |
296 | && TREE_CODE (TYPE_MAX_VALUE (domain)) | |
297 | == INTEGER_CST | |
298 | && tree_int_cst_lt (TREE_OPERAND (v, 1), | |
299 | TYPE_MAX_VALUE (domain))) | |
300 | { | |
301 | v = NULL_TREE; | |
302 | break; | |
303 | } | |
304 | } | |
305 | v = TREE_OPERAND (v, 0); | |
306 | break; | |
307 | case REALPART_EXPR: | |
308 | case IMAGPART_EXPR: | |
309 | v = NULL_TREE; | |
310 | break; | |
311 | case COMPONENT_REF: | |
5dc67ab1 | 312 | if (TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE) |
313 | { | |
314 | v = NULL_TREE; | |
315 | break; | |
316 | } | |
ffbeca59 | 317 | while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) |
318 | if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
319 | != UNION_TYPE | |
320 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
321 | != QUAL_UNION_TYPE) | |
322 | break; | |
323 | else | |
324 | v = TREE_OPERAND (v, 0); | |
325 | if (TREE_CODE (v) == COMPONENT_REF | |
326 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
327 | == RECORD_TYPE) | |
fbc1ccbc | 328 | { |
1767a056 | 329 | tree fld_chain = DECL_CHAIN (TREE_OPERAND (v, 1)); |
330 | for (; fld_chain; fld_chain = DECL_CHAIN (fld_chain)) | |
5dc67ab1 | 331 | if (TREE_CODE (fld_chain) == FIELD_DECL) |
332 | break; | |
333 | ||
334 | if (fld_chain) | |
335 | { | |
336 | v = NULL_TREE; | |
fbc1ccbc | 337 | break; |
5dc67ab1 | 338 | } |
ffbeca59 | 339 | v = TREE_OPERAND (v, 0); |
fbc1ccbc | 340 | } |
ffbeca59 | 341 | while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) |
342 | if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
343 | != UNION_TYPE | |
344 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
345 | != QUAL_UNION_TYPE) | |
5dc67ab1 | 346 | break; |
347 | else | |
348 | v = TREE_OPERAND (v, 0); | |
ffbeca59 | 349 | if (v != pt_var) |
5dc67ab1 | 350 | v = NULL_TREE; |
351 | else | |
352 | v = pt_var; | |
fbc1ccbc | 353 | break; |
354 | default: | |
355 | v = pt_var; | |
356 | break; | |
357 | } | |
358 | if (v == pt_var) | |
0a39fd54 | 359 | var = pt_var; |
360 | } | |
fbc1ccbc | 361 | } |
362 | else | |
363 | var = pt_var; | |
0a39fd54 | 364 | |
fbc1ccbc | 365 | if (var != pt_var) |
366 | var_size = TYPE_SIZE_UNIT (TREE_TYPE (var)); | |
367 | else if (!pt_var_size) | |
4e91a07b | 368 | return false; |
fbc1ccbc | 369 | else |
370 | var_size = pt_var_size; | |
371 | bytes = compute_object_offset (TREE_OPERAND (ptr, 0), var); | |
372 | if (bytes != error_mark_node) | |
373 | { | |
374 | if (TREE_CODE (bytes) == INTEGER_CST | |
375 | && tree_int_cst_lt (var_size, bytes)) | |
376 | bytes = size_zero_node; | |
377 | else | |
378 | bytes = size_binop (MINUS_EXPR, var_size, bytes); | |
379 | } | |
380 | if (var != pt_var | |
381 | && pt_var_size | |
182cf5a9 | 382 | && TREE_CODE (pt_var) == MEM_REF |
fbc1ccbc | 383 | && bytes != error_mark_node) |
384 | { | |
385 | tree bytes2 = compute_object_offset (TREE_OPERAND (ptr, 0), pt_var); | |
386 | if (bytes2 != error_mark_node) | |
0a39fd54 | 387 | { |
fbc1ccbc | 388 | if (TREE_CODE (bytes2) == INTEGER_CST |
389 | && tree_int_cst_lt (pt_var_size, bytes2)) | |
390 | bytes2 = size_zero_node; | |
0a39fd54 | 391 | else |
56b5c963 | 392 | bytes2 = size_binop (MINUS_EXPR, pt_var_size, bytes2); |
fbc1ccbc | 393 | bytes = size_binop (MIN_EXPR, bytes, bytes2); |
0a39fd54 | 394 | } |
395 | } | |
0a39fd54 | 396 | } |
fbc1ccbc | 397 | else if (!pt_var_size) |
4e91a07b | 398 | return false; |
fbc1ccbc | 399 | else |
400 | bytes = pt_var_size; | |
401 | ||
e913b5cd | 402 | if (tree_fits_uhwi_p (bytes)) |
4e91a07b | 403 | { |
404 | *psize = tree_to_uhwi (bytes); | |
405 | return true; | |
406 | } | |
0a39fd54 | 407 | |
4e91a07b | 408 | return false; |
0a39fd54 | 409 | } |
410 | ||
411 | ||
75a70cf9 | 412 | /* Compute __builtin_object_size for CALL, which is a GIMPLE_CALL. |
0f15b7f6 | 413 | Handles calls to functions declared with attribute alloc_size. |
414 | OBJECT_SIZE_TYPE is the second argument from __builtin_object_size. | |
415 | If unknown, return unknown[object_size_type]. */ | |
0a39fd54 | 416 | |
417 | static unsigned HOST_WIDE_INT | |
1a91d914 | 418 | alloc_object_size (const gcall *call, int object_size_type) |
0a39fd54 | 419 | { |
75a70cf9 | 420 | gcc_assert (is_gimple_call (call)); |
0a39fd54 | 421 | |
0f15b7f6 | 422 | tree calltype; |
423 | if (tree callfn = gimple_call_fndecl (call)) | |
424 | calltype = TREE_TYPE (callfn); | |
425 | else | |
426 | calltype = gimple_call_fntype (call); | |
427 | ||
428 | if (!calltype) | |
4a29c97c | 429 | return unknown[object_size_type]; |
430 | ||
0f15b7f6 | 431 | /* Set to positions of alloc_size arguments. */ |
432 | int arg1 = -1, arg2 = -1; | |
433 | tree alloc_size = lookup_attribute ("alloc_size", | |
434 | TYPE_ATTRIBUTES (calltype)); | |
4a29c97c | 435 | if (alloc_size && TREE_VALUE (alloc_size)) |
436 | { | |
437 | tree p = TREE_VALUE (alloc_size); | |
438 | ||
f9ae6f95 | 439 | arg1 = TREE_INT_CST_LOW (TREE_VALUE (p))-1; |
4a29c97c | 440 | if (TREE_CHAIN (p)) |
f9ae6f95 | 441 | arg2 = TREE_INT_CST_LOW (TREE_VALUE (TREE_CHAIN (p)))-1; |
4a29c97c | 442 | } |
48e1416a | 443 | |
75a70cf9 | 444 | if (arg1 < 0 || arg1 >= (int)gimple_call_num_args (call) |
445 | || TREE_CODE (gimple_call_arg (call, arg1)) != INTEGER_CST | |
48e1416a | 446 | || (arg2 >= 0 |
75a70cf9 | 447 | && (arg2 >= (int)gimple_call_num_args (call) |
448 | || TREE_CODE (gimple_call_arg (call, arg2)) != INTEGER_CST))) | |
48e1416a | 449 | return unknown[object_size_type]; |
4a29c97c | 450 | |
0f15b7f6 | 451 | tree bytes = NULL_TREE; |
4a29c97c | 452 | if (arg2 >= 0) |
453 | bytes = size_binop (MULT_EXPR, | |
75a70cf9 | 454 | fold_convert (sizetype, gimple_call_arg (call, arg1)), |
455 | fold_convert (sizetype, gimple_call_arg (call, arg2))); | |
4a29c97c | 456 | else if (arg1 >= 0) |
75a70cf9 | 457 | bytes = fold_convert (sizetype, gimple_call_arg (call, arg1)); |
4a29c97c | 458 | |
e913b5cd | 459 | if (bytes && tree_fits_uhwi_p (bytes)) |
460 | return tree_to_uhwi (bytes); | |
0a39fd54 | 461 | |
462 | return unknown[object_size_type]; | |
463 | } | |
464 | ||
465 | ||
466 | /* If object size is propagated from one of function's arguments directly | |
75a70cf9 | 467 | to its return value, return that argument for GIMPLE_CALL statement CALL. |
0a39fd54 | 468 | Otherwise return NULL. */ |
469 | ||
470 | static tree | |
1a91d914 | 471 | pass_through_call (const gcall *call) |
0a39fd54 | 472 | { |
4ef5e689 | 473 | unsigned rf = gimple_call_return_flags (call); |
474 | if (rf & ERF_RETURNS_ARG) | |
475 | { | |
476 | unsigned argnum = rf & ERF_RETURN_ARG_MASK; | |
477 | if (argnum < gimple_call_num_args (call)) | |
478 | return gimple_call_arg (call, argnum); | |
479 | } | |
0a39fd54 | 480 | |
4ef5e689 | 481 | /* __builtin_assume_aligned is intentionally not marked RET1. */ |
482 | if (gimple_call_builtin_p (call, BUILT_IN_ASSUME_ALIGNED)) | |
483 | return gimple_call_arg (call, 0); | |
0a39fd54 | 484 | |
485 | return NULL_TREE; | |
486 | } | |
487 | ||
488 | ||
4e91a07b | 489 | /* Compute __builtin_object_size value for PTR and set *PSIZE to |
2beadd91 | 490 | the resulting value. If the declared object is known and PDECL |
491 | is nonnull, sets *PDECL to the object's DECL. OBJECT_SIZE_TYPE | |
492 | is the second argument to __builtin_object_size. | |
493 | Returns true on success and false when the object size could not | |
494 | be determined. */ | |
0a39fd54 | 495 | |
4e91a07b | 496 | bool |
497 | compute_builtin_object_size (tree ptr, int object_size_type, | |
2beadd91 | 498 | unsigned HOST_WIDE_INT *psize, |
499 | tree *pdecl /* = NULL */) | |
0a39fd54 | 500 | { |
501 | gcc_assert (object_size_type >= 0 && object_size_type <= 3); | |
502 | ||
4e91a07b | 503 | /* Set to unknown and overwrite just before returning if the size |
504 | could be determined. */ | |
505 | *psize = unknown[object_size_type]; | |
506 | ||
0a39fd54 | 507 | if (! offset_limit) |
508 | init_offset_limit (); | |
509 | ||
510 | if (TREE_CODE (ptr) == ADDR_EXPR) | |
2beadd91 | 511 | return addr_object_size (NULL, ptr, object_size_type, psize, pdecl); |
4e91a07b | 512 | |
513 | if (TREE_CODE (ptr) != SSA_NAME | |
514 | || !POINTER_TYPE_P (TREE_TYPE (ptr))) | |
515 | return false; | |
0a39fd54 | 516 | |
4e91a07b | 517 | if (computed[object_size_type] == NULL) |
0a39fd54 | 518 | { |
4e91a07b | 519 | if (optimize || object_size_type & 1) |
520 | return false; | |
521 | ||
522 | /* When not optimizing, rather than failing, make a small effort | |
523 | to determine the object size without the full benefit of | |
524 | the (costly) computation below. */ | |
525 | gimple *def = SSA_NAME_DEF_STMT (ptr); | |
526 | if (gimple_code (def) == GIMPLE_ASSIGN) | |
0a39fd54 | 527 | { |
4e91a07b | 528 | tree_code code = gimple_assign_rhs_code (def); |
529 | if (code == POINTER_PLUS_EXPR) | |
0a39fd54 | 530 | { |
4e91a07b | 531 | tree offset = gimple_assign_rhs2 (def); |
532 | ptr = gimple_assign_rhs1 (def); | |
0a39fd54 | 533 | |
17dba507 | 534 | if (tree_fits_shwi_p (offset) |
2beadd91 | 535 | && compute_builtin_object_size (ptr, object_size_type, |
536 | psize, pdecl)) | |
0a39fd54 | 537 | { |
4e91a07b | 538 | /* Return zero when the offset is out of bounds. */ |
539 | unsigned HOST_WIDE_INT off = tree_to_shwi (offset); | |
540 | *psize = off < *psize ? *psize - off : 0; | |
541 | return true; | |
0a39fd54 | 542 | } |
4e91a07b | 543 | } |
544 | } | |
545 | return false; | |
546 | } | |
0a39fd54 | 547 | |
4e91a07b | 548 | if (!bitmap_bit_p (computed[object_size_type], SSA_NAME_VERSION (ptr))) |
549 | { | |
550 | struct object_size_info osi; | |
551 | bitmap_iterator bi; | |
552 | unsigned int i; | |
553 | ||
554 | if (num_ssa_names > object_sizes[object_size_type].length ()) | |
555 | object_sizes[object_size_type].safe_grow (num_ssa_names); | |
556 | if (dump_file) | |
557 | { | |
558 | fprintf (dump_file, "Computing %s %sobject size for ", | |
559 | (object_size_type & 2) ? "minimum" : "maximum", | |
560 | (object_size_type & 1) ? "sub" : ""); | |
561 | print_generic_expr (dump_file, ptr, dump_flags); | |
562 | fprintf (dump_file, ":\n"); | |
563 | } | |
0a39fd54 | 564 | |
4e91a07b | 565 | osi.visited = BITMAP_ALLOC (NULL); |
566 | osi.reexamine = BITMAP_ALLOC (NULL); | |
567 | osi.object_size_type = object_size_type; | |
568 | osi.depths = NULL; | |
569 | osi.stack = NULL; | |
570 | osi.tos = NULL; | |
571 | ||
572 | /* First pass: walk UD chains, compute object sizes that | |
573 | can be computed. osi.reexamine bitmap at the end will | |
574 | contain what variables were found in dependency cycles | |
575 | and therefore need to be reexamined. */ | |
576 | osi.pass = 0; | |
577 | osi.changed = false; | |
578 | collect_object_sizes_for (&osi, ptr); | |
579 | ||
580 | /* Second pass: keep recomputing object sizes of variables | |
581 | that need reexamination, until no object sizes are | |
582 | increased or all object sizes are computed. */ | |
583 | if (! bitmap_empty_p (osi.reexamine)) | |
584 | { | |
585 | bitmap reexamine = BITMAP_ALLOC (NULL); | |
586 | ||
587 | /* If looking for minimum instead of maximum object size, | |
588 | detect cases where a pointer is increased in a loop. | |
589 | Although even without this detection pass 2 would eventually | |
590 | terminate, it could take a long time. If a pointer is | |
591 | increasing this way, we need to assume 0 object size. | |
592 | E.g. p = &buf[0]; while (cond) p = p + 4; */ | |
593 | if (object_size_type & 2) | |
594 | { | |
595 | osi.depths = XCNEWVEC (unsigned int, num_ssa_names); | |
596 | osi.stack = XNEWVEC (unsigned int, num_ssa_names); | |
597 | osi.tos = osi.stack; | |
598 | osi.pass = 1; | |
599 | /* collect_object_sizes_for is changing | |
600 | osi.reexamine bitmap, so iterate over a copy. */ | |
601 | bitmap_copy (reexamine, osi.reexamine); | |
602 | EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi) | |
603 | if (bitmap_bit_p (osi.reexamine, i)) | |
604 | check_for_plus_in_loops (&osi, ssa_name (i)); | |
605 | ||
606 | free (osi.depths); | |
607 | osi.depths = NULL; | |
608 | free (osi.stack); | |
609 | osi.stack = NULL; | |
610 | osi.tos = NULL; | |
0a39fd54 | 611 | } |
0a39fd54 | 612 | |
4e91a07b | 613 | do |
0a39fd54 | 614 | { |
4e91a07b | 615 | osi.pass = 2; |
616 | osi.changed = false; | |
617 | /* collect_object_sizes_for is changing | |
618 | osi.reexamine bitmap, so iterate over a copy. */ | |
619 | bitmap_copy (reexamine, osi.reexamine); | |
620 | EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi) | |
621 | if (bitmap_bit_p (osi.reexamine, i)) | |
0a39fd54 | 622 | { |
4e91a07b | 623 | collect_object_sizes_for (&osi, ssa_name (i)); |
624 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
625 | { | |
626 | fprintf (dump_file, "Reexamining "); | |
627 | print_generic_expr (dump_file, ssa_name (i), | |
628 | dump_flags); | |
629 | fprintf (dump_file, "\n"); | |
630 | } | |
0a39fd54 | 631 | } |
632 | } | |
4e91a07b | 633 | while (osi.changed); |
0a39fd54 | 634 | |
4e91a07b | 635 | BITMAP_FREE (reexamine); |
0a39fd54 | 636 | } |
4e91a07b | 637 | EXECUTE_IF_SET_IN_BITMAP (osi.reexamine, 0, i, bi) |
638 | bitmap_set_bit (computed[object_size_type], i); | |
0a39fd54 | 639 | |
4e91a07b | 640 | /* Debugging dumps. */ |
641 | if (dump_file) | |
642 | { | |
643 | EXECUTE_IF_SET_IN_BITMAP (osi.visited, 0, i, bi) | |
644 | if (object_sizes[object_size_type][i] | |
645 | != unknown[object_size_type]) | |
646 | { | |
647 | print_generic_expr (dump_file, ssa_name (i), | |
648 | dump_flags); | |
649 | fprintf (dump_file, | |
650 | ": %s %sobject size " | |
651 | HOST_WIDE_INT_PRINT_UNSIGNED "\n", | |
652 | (object_size_type & 2) ? "minimum" : "maximum", | |
653 | (object_size_type & 1) ? "sub" : "", | |
654 | object_sizes[object_size_type][i]); | |
655 | } | |
656 | } | |
657 | ||
658 | BITMAP_FREE (osi.reexamine); | |
659 | BITMAP_FREE (osi.visited); | |
0a39fd54 | 660 | } |
661 | ||
4e91a07b | 662 | *psize = object_sizes[object_size_type][SSA_NAME_VERSION (ptr)]; |
663 | return *psize != unknown[object_size_type]; | |
0a39fd54 | 664 | } |
665 | ||
75a70cf9 | 666 | /* Compute object_sizes for PTR, defined to VALUE, which is not an SSA_NAME. */ |
0a39fd54 | 667 | |
668 | static void | |
669 | expr_object_size (struct object_size_info *osi, tree ptr, tree value) | |
670 | { | |
671 | int object_size_type = osi->object_size_type; | |
672 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
673 | unsigned HOST_WIDE_INT bytes; | |
674 | ||
675 | gcc_assert (object_sizes[object_size_type][varno] | |
676 | != unknown[object_size_type]); | |
677 | gcc_assert (osi->pass == 0); | |
678 | ||
679 | if (TREE_CODE (value) == WITH_SIZE_EXPR) | |
680 | value = TREE_OPERAND (value, 0); | |
681 | ||
682 | /* Pointer variables should have been handled by merge_object_sizes. */ | |
683 | gcc_assert (TREE_CODE (value) != SSA_NAME | |
684 | || !POINTER_TYPE_P (TREE_TYPE (value))); | |
685 | ||
686 | if (TREE_CODE (value) == ADDR_EXPR) | |
4e91a07b | 687 | addr_object_size (osi, value, object_size_type, &bytes); |
0a39fd54 | 688 | else |
689 | bytes = unknown[object_size_type]; | |
690 | ||
691 | if ((object_size_type & 2) == 0) | |
692 | { | |
693 | if (object_sizes[object_size_type][varno] < bytes) | |
694 | object_sizes[object_size_type][varno] = bytes; | |
695 | } | |
696 | else | |
697 | { | |
698 | if (object_sizes[object_size_type][varno] > bytes) | |
699 | object_sizes[object_size_type][varno] = bytes; | |
700 | } | |
701 | } | |
702 | ||
703 | ||
75a70cf9 | 704 | /* Compute object_sizes for PTR, defined to the result of a call. */ |
705 | ||
706 | static void | |
1a91d914 | 707 | call_object_size (struct object_size_info *osi, tree ptr, gcall *call) |
75a70cf9 | 708 | { |
709 | int object_size_type = osi->object_size_type; | |
710 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
711 | unsigned HOST_WIDE_INT bytes; | |
712 | ||
713 | gcc_assert (is_gimple_call (call)); | |
714 | ||
715 | gcc_assert (object_sizes[object_size_type][varno] | |
716 | != unknown[object_size_type]); | |
717 | gcc_assert (osi->pass == 0); | |
718 | ||
719 | bytes = alloc_object_size (call, object_size_type); | |
720 | ||
721 | if ((object_size_type & 2) == 0) | |
722 | { | |
723 | if (object_sizes[object_size_type][varno] < bytes) | |
724 | object_sizes[object_size_type][varno] = bytes; | |
725 | } | |
726 | else | |
727 | { | |
728 | if (object_sizes[object_size_type][varno] > bytes) | |
729 | object_sizes[object_size_type][varno] = bytes; | |
730 | } | |
731 | } | |
732 | ||
733 | ||
734 | /* Compute object_sizes for PTR, defined to an unknown value. */ | |
735 | ||
736 | static void | |
737 | unknown_object_size (struct object_size_info *osi, tree ptr) | |
738 | { | |
739 | int object_size_type = osi->object_size_type; | |
740 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
741 | unsigned HOST_WIDE_INT bytes; | |
742 | ||
743 | gcc_assert (object_sizes[object_size_type][varno] | |
744 | != unknown[object_size_type]); | |
745 | gcc_assert (osi->pass == 0); | |
746 | ||
747 | bytes = unknown[object_size_type]; | |
748 | ||
749 | if ((object_size_type & 2) == 0) | |
750 | { | |
751 | if (object_sizes[object_size_type][varno] < bytes) | |
752 | object_sizes[object_size_type][varno] = bytes; | |
753 | } | |
754 | else | |
755 | { | |
756 | if (object_sizes[object_size_type][varno] > bytes) | |
757 | object_sizes[object_size_type][varno] = bytes; | |
758 | } | |
759 | } | |
760 | ||
761 | ||
0a39fd54 | 762 | /* Merge object sizes of ORIG + OFFSET into DEST. Return true if |
763 | the object size might need reexamination later. */ | |
764 | ||
765 | static bool | |
766 | merge_object_sizes (struct object_size_info *osi, tree dest, tree orig, | |
767 | unsigned HOST_WIDE_INT offset) | |
768 | { | |
769 | int object_size_type = osi->object_size_type; | |
770 | unsigned int varno = SSA_NAME_VERSION (dest); | |
771 | unsigned HOST_WIDE_INT orig_bytes; | |
772 | ||
773 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
774 | return false; | |
775 | if (offset >= offset_limit) | |
776 | { | |
777 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
778 | return false; | |
779 | } | |
780 | ||
781 | if (osi->pass == 0) | |
782 | collect_object_sizes_for (osi, orig); | |
783 | ||
784 | orig_bytes = object_sizes[object_size_type][SSA_NAME_VERSION (orig)]; | |
785 | if (orig_bytes != unknown[object_size_type]) | |
786 | orig_bytes = (offset > orig_bytes) | |
457daa4e | 787 | ? HOST_WIDE_INT_0U : orig_bytes - offset; |
0a39fd54 | 788 | |
789 | if ((object_size_type & 2) == 0) | |
790 | { | |
791 | if (object_sizes[object_size_type][varno] < orig_bytes) | |
792 | { | |
793 | object_sizes[object_size_type][varno] = orig_bytes; | |
794 | osi->changed = true; | |
795 | } | |
796 | } | |
797 | else | |
798 | { | |
799 | if (object_sizes[object_size_type][varno] > orig_bytes) | |
800 | { | |
801 | object_sizes[object_size_type][varno] = orig_bytes; | |
802 | osi->changed = true; | |
803 | } | |
804 | } | |
805 | return bitmap_bit_p (osi->reexamine, SSA_NAME_VERSION (orig)); | |
806 | } | |
807 | ||
808 | ||
75a70cf9 | 809 | /* Compute object_sizes for VAR, defined to the result of an assignment |
810 | with operator POINTER_PLUS_EXPR. Return true if the object size might | |
811 | need reexamination later. */ | |
0a39fd54 | 812 | |
813 | static bool | |
42acab1c | 814 | plus_stmt_object_size (struct object_size_info *osi, tree var, gimple *stmt) |
0a39fd54 | 815 | { |
0a39fd54 | 816 | int object_size_type = osi->object_size_type; |
817 | unsigned int varno = SSA_NAME_VERSION (var); | |
818 | unsigned HOST_WIDE_INT bytes; | |
75a70cf9 | 819 | tree op0, op1; |
820 | ||
182cf5a9 | 821 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) |
822 | { | |
823 | op0 = gimple_assign_rhs1 (stmt); | |
824 | op1 = gimple_assign_rhs2 (stmt); | |
825 | } | |
826 | else if (gimple_assign_rhs_code (stmt) == ADDR_EXPR) | |
827 | { | |
828 | tree rhs = TREE_OPERAND (gimple_assign_rhs1 (stmt), 0); | |
829 | gcc_assert (TREE_CODE (rhs) == MEM_REF); | |
830 | op0 = TREE_OPERAND (rhs, 0); | |
831 | op1 = TREE_OPERAND (rhs, 1); | |
832 | } | |
833 | else | |
834 | gcc_unreachable (); | |
0a39fd54 | 835 | |
836 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
837 | return false; | |
838 | ||
0a39fd54 | 839 | /* Handle PTR + OFFSET here. */ |
0de36bdb | 840 | if (TREE_CODE (op1) == INTEGER_CST |
0a39fd54 | 841 | && (TREE_CODE (op0) == SSA_NAME |
842 | || TREE_CODE (op0) == ADDR_EXPR)) | |
843 | { | |
e913b5cd | 844 | if (! tree_fits_uhwi_p (op1)) |
0a39fd54 | 845 | bytes = unknown[object_size_type]; |
846 | else if (TREE_CODE (op0) == SSA_NAME) | |
e913b5cd | 847 | return merge_object_sizes (osi, var, op0, tree_to_uhwi (op1)); |
0a39fd54 | 848 | else |
849 | { | |
e913b5cd | 850 | unsigned HOST_WIDE_INT off = tree_to_uhwi (op1); |
0a39fd54 | 851 | |
75a70cf9 | 852 | /* op0 will be ADDR_EXPR here. */ |
4e91a07b | 853 | addr_object_size (osi, op0, object_size_type, &bytes); |
06f9fe3e | 854 | if (bytes == unknown[object_size_type]) |
855 | ; | |
856 | else if (off > offset_limit) | |
0a39fd54 | 857 | bytes = unknown[object_size_type]; |
858 | else if (off > bytes) | |
859 | bytes = 0; | |
860 | else | |
861 | bytes -= off; | |
862 | } | |
863 | } | |
864 | else | |
865 | bytes = unknown[object_size_type]; | |
866 | ||
867 | if ((object_size_type & 2) == 0) | |
868 | { | |
869 | if (object_sizes[object_size_type][varno] < bytes) | |
870 | object_sizes[object_size_type][varno] = bytes; | |
871 | } | |
872 | else | |
873 | { | |
874 | if (object_sizes[object_size_type][varno] > bytes) | |
875 | object_sizes[object_size_type][varno] = bytes; | |
876 | } | |
877 | return false; | |
878 | } | |
879 | ||
880 | ||
8a2caf10 | 881 | /* Compute object_sizes for VAR, defined at STMT, which is |
ec0fa513 | 882 | a COND_EXPR. Return true if the object size might need reexamination |
883 | later. */ | |
884 | ||
885 | static bool | |
42acab1c | 886 | cond_expr_object_size (struct object_size_info *osi, tree var, gimple *stmt) |
ec0fa513 | 887 | { |
888 | tree then_, else_; | |
889 | int object_size_type = osi->object_size_type; | |
890 | unsigned int varno = SSA_NAME_VERSION (var); | |
891 | bool reexamine = false; | |
892 | ||
8a2caf10 | 893 | gcc_assert (gimple_assign_rhs_code (stmt) == COND_EXPR); |
ec0fa513 | 894 | |
895 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
896 | return false; | |
897 | ||
8a2caf10 | 898 | then_ = gimple_assign_rhs2 (stmt); |
899 | else_ = gimple_assign_rhs3 (stmt); | |
ec0fa513 | 900 | |
901 | if (TREE_CODE (then_) == SSA_NAME) | |
902 | reexamine |= merge_object_sizes (osi, var, then_, 0); | |
903 | else | |
904 | expr_object_size (osi, var, then_); | |
905 | ||
bb2c0c3e | 906 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) |
907 | return reexamine; | |
908 | ||
ec0fa513 | 909 | if (TREE_CODE (else_) == SSA_NAME) |
910 | reexamine |= merge_object_sizes (osi, var, else_, 0); | |
911 | else | |
912 | expr_object_size (osi, var, else_); | |
913 | ||
914 | return reexamine; | |
915 | } | |
916 | ||
0a39fd54 | 917 | /* Compute object sizes for VAR. |
918 | For ADDR_EXPR an object size is the number of remaining bytes | |
56d36a49 | 919 | to the end of the object (where what is considered an object depends on |
0a39fd54 | 920 | OSI->object_size_type). |
75a70cf9 | 921 | For allocation GIMPLE_CALL like malloc or calloc object size is the size |
0a39fd54 | 922 | of the allocation. |
0de36bdb | 923 | For POINTER_PLUS_EXPR where second operand is a constant integer, |
0a39fd54 | 924 | object size is object size of the first operand minus the constant. |
925 | If the constant is bigger than the number of remaining bytes until the | |
926 | end of the object, object size is 0, but if it is instead a pointer | |
927 | subtraction, object size is unknown[object_size_type]. | |
928 | To differentiate addition from subtraction, ADDR_EXPR returns | |
929 | unknown[object_size_type] for all objects bigger than half of the address | |
930 | space, and constants less than half of the address space are considered | |
931 | addition, while bigger constants subtraction. | |
75a70cf9 | 932 | For a memcpy like GIMPLE_CALL that always returns one of its arguments, the |
0a39fd54 | 933 | object size is object size of that argument. |
934 | Otherwise, object size is the maximum of object sizes of variables | |
935 | that it might be set to. */ | |
936 | ||
937 | static void | |
938 | collect_object_sizes_for (struct object_size_info *osi, tree var) | |
939 | { | |
940 | int object_size_type = osi->object_size_type; | |
941 | unsigned int varno = SSA_NAME_VERSION (var); | |
42acab1c | 942 | gimple *stmt; |
0a39fd54 | 943 | bool reexamine; |
944 | ||
945 | if (bitmap_bit_p (computed[object_size_type], varno)) | |
946 | return; | |
947 | ||
948 | if (osi->pass == 0) | |
949 | { | |
6ef9bbe0 | 950 | if (bitmap_set_bit (osi->visited, varno)) |
0a39fd54 | 951 | { |
0a39fd54 | 952 | object_sizes[object_size_type][varno] |
953 | = (object_size_type & 2) ? -1 : 0; | |
954 | } | |
955 | else | |
956 | { | |
957 | /* Found a dependency loop. Mark the variable for later | |
958 | re-examination. */ | |
959 | bitmap_set_bit (osi->reexamine, varno); | |
960 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
961 | { | |
962 | fprintf (dump_file, "Found a dependency loop at "); | |
963 | print_generic_expr (dump_file, var, dump_flags); | |
964 | fprintf (dump_file, "\n"); | |
965 | } | |
966 | return; | |
967 | } | |
968 | } | |
969 | ||
970 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
971 | { | |
972 | fprintf (dump_file, "Visiting use-def links for "); | |
973 | print_generic_expr (dump_file, var, dump_flags); | |
974 | fprintf (dump_file, "\n"); | |
975 | } | |
976 | ||
977 | stmt = SSA_NAME_DEF_STMT (var); | |
978 | reexamine = false; | |
979 | ||
75a70cf9 | 980 | switch (gimple_code (stmt)) |
0a39fd54 | 981 | { |
75a70cf9 | 982 | case GIMPLE_ASSIGN: |
0a39fd54 | 983 | { |
182cf5a9 | 984 | tree rhs = gimple_assign_rhs1 (stmt); |
985 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR | |
986 | || (gimple_assign_rhs_code (stmt) == ADDR_EXPR | |
987 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == MEM_REF)) | |
75a70cf9 | 988 | reexamine = plus_stmt_object_size (osi, var, stmt); |
8a2caf10 | 989 | else if (gimple_assign_rhs_code (stmt) == COND_EXPR) |
990 | reexamine = cond_expr_object_size (osi, var, stmt); | |
75a70cf9 | 991 | else if (gimple_assign_single_p (stmt) |
992 | || gimple_assign_unary_nop_p (stmt)) | |
993 | { | |
75a70cf9 | 994 | if (TREE_CODE (rhs) == SSA_NAME |
995 | && POINTER_TYPE_P (TREE_TYPE (rhs))) | |
996 | reexamine = merge_object_sizes (osi, var, rhs, 0); | |
75a70cf9 | 997 | else |
998 | expr_object_size (osi, var, rhs); | |
999 | } | |
1000 | else | |
1001 | unknown_object_size (osi, var); | |
1002 | break; | |
1003 | } | |
ec0fa513 | 1004 | |
75a70cf9 | 1005 | case GIMPLE_CALL: |
1006 | { | |
1a91d914 | 1007 | gcall *call_stmt = as_a <gcall *> (stmt); |
1008 | tree arg = pass_through_call (call_stmt); | |
75a70cf9 | 1009 | if (arg) |
1010 | { | |
1011 | if (TREE_CODE (arg) == SSA_NAME | |
1012 | && POINTER_TYPE_P (TREE_TYPE (arg))) | |
1013 | reexamine = merge_object_sizes (osi, var, arg, 0); | |
75a70cf9 | 1014 | else |
1015 | expr_object_size (osi, var, arg); | |
1016 | } | |
1017 | else | |
1a91d914 | 1018 | call_object_size (osi, var, call_stmt); |
0a39fd54 | 1019 | break; |
1020 | } | |
1021 | ||
75a70cf9 | 1022 | case GIMPLE_ASM: |
0a39fd54 | 1023 | /* Pointers defined by __asm__ statements can point anywhere. */ |
1024 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
1025 | break; | |
1026 | ||
75a70cf9 | 1027 | case GIMPLE_NOP: |
ec11736b | 1028 | if (SSA_NAME_VAR (var) |
1029 | && TREE_CODE (SSA_NAME_VAR (var)) == PARM_DECL) | |
1030 | expr_object_size (osi, var, SSA_NAME_VAR (var)); | |
1031 | else | |
1032 | /* Uninitialized SSA names point nowhere. */ | |
1033 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
0a39fd54 | 1034 | break; |
1035 | ||
75a70cf9 | 1036 | case GIMPLE_PHI: |
0a39fd54 | 1037 | { |
75a70cf9 | 1038 | unsigned i; |
0a39fd54 | 1039 | |
75a70cf9 | 1040 | for (i = 0; i < gimple_phi_num_args (stmt); i++) |
0a39fd54 | 1041 | { |
75a70cf9 | 1042 | tree rhs = gimple_phi_arg (stmt, i)->def; |
0a39fd54 | 1043 | |
1044 | if (object_sizes[object_size_type][varno] | |
1045 | == unknown[object_size_type]) | |
1046 | break; | |
1047 | ||
1048 | if (TREE_CODE (rhs) == SSA_NAME) | |
1049 | reexamine |= merge_object_sizes (osi, var, rhs, 0); | |
1050 | else if (osi->pass == 0) | |
1051 | expr_object_size (osi, var, rhs); | |
1052 | } | |
1053 | break; | |
1054 | } | |
75a70cf9 | 1055 | |
0a39fd54 | 1056 | default: |
1057 | gcc_unreachable (); | |
1058 | } | |
1059 | ||
1060 | if (! reexamine | |
1061 | || object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
1062 | { | |
1063 | bitmap_set_bit (computed[object_size_type], varno); | |
1064 | bitmap_clear_bit (osi->reexamine, varno); | |
1065 | } | |
1066 | else | |
1067 | { | |
1068 | bitmap_set_bit (osi->reexamine, varno); | |
1069 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1070 | { | |
1071 | fprintf (dump_file, "Need to reexamine "); | |
1072 | print_generic_expr (dump_file, var, dump_flags); | |
1073 | fprintf (dump_file, "\n"); | |
1074 | } | |
1075 | } | |
1076 | } | |
1077 | ||
1078 | ||
1079 | /* Helper function for check_for_plus_in_loops. Called recursively | |
1080 | to detect loops. */ | |
1081 | ||
1082 | static void | |
1083 | check_for_plus_in_loops_1 (struct object_size_info *osi, tree var, | |
1084 | unsigned int depth) | |
1085 | { | |
42acab1c | 1086 | gimple *stmt = SSA_NAME_DEF_STMT (var); |
0a39fd54 | 1087 | unsigned int varno = SSA_NAME_VERSION (var); |
1088 | ||
1089 | if (osi->depths[varno]) | |
1090 | { | |
1091 | if (osi->depths[varno] != depth) | |
1092 | { | |
1093 | unsigned int *sp; | |
1094 | ||
1095 | /* Found a loop involving pointer addition. */ | |
1096 | for (sp = osi->tos; sp > osi->stack; ) | |
1097 | { | |
1098 | --sp; | |
1099 | bitmap_clear_bit (osi->reexamine, *sp); | |
1100 | bitmap_set_bit (computed[osi->object_size_type], *sp); | |
1101 | object_sizes[osi->object_size_type][*sp] = 0; | |
1102 | if (*sp == varno) | |
1103 | break; | |
1104 | } | |
1105 | } | |
1106 | return; | |
1107 | } | |
1108 | else if (! bitmap_bit_p (osi->reexamine, varno)) | |
1109 | return; | |
1110 | ||
1111 | osi->depths[varno] = depth; | |
1112 | *osi->tos++ = varno; | |
1113 | ||
75a70cf9 | 1114 | switch (gimple_code (stmt)) |
0a39fd54 | 1115 | { |
0a39fd54 | 1116 | |
75a70cf9 | 1117 | case GIMPLE_ASSIGN: |
0a39fd54 | 1118 | { |
75a70cf9 | 1119 | if ((gimple_assign_single_p (stmt) |
1120 | || gimple_assign_unary_nop_p (stmt)) | |
1121 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
1122 | { | |
1123 | tree rhs = gimple_assign_rhs1 (stmt); | |
1124 | ||
1125 | check_for_plus_in_loops_1 (osi, rhs, depth); | |
1126 | } | |
1127 | else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) | |
1128 | { | |
1129 | tree basevar = gimple_assign_rhs1 (stmt); | |
1130 | tree cst = gimple_assign_rhs2 (stmt); | |
1131 | ||
1132 | gcc_assert (TREE_CODE (cst) == INTEGER_CST); | |
1133 | ||
1134 | check_for_plus_in_loops_1 (osi, basevar, | |
1135 | depth + !integer_zerop (cst)); | |
1136 | } | |
1137 | else | |
1138 | gcc_unreachable (); | |
1139 | break; | |
1140 | } | |
0a39fd54 | 1141 | |
75a70cf9 | 1142 | case GIMPLE_CALL: |
1143 | { | |
1a91d914 | 1144 | gcall *call_stmt = as_a <gcall *> (stmt); |
1145 | tree arg = pass_through_call (call_stmt); | |
75a70cf9 | 1146 | if (arg) |
1147 | { | |
1148 | if (TREE_CODE (arg) == SSA_NAME) | |
1149 | check_for_plus_in_loops_1 (osi, arg, depth); | |
1150 | else | |
1151 | gcc_unreachable (); | |
1152 | } | |
1153 | break; | |
0a39fd54 | 1154 | } |
75a70cf9 | 1155 | |
1156 | case GIMPLE_PHI: | |
0a39fd54 | 1157 | { |
75a70cf9 | 1158 | unsigned i; |
0a39fd54 | 1159 | |
75a70cf9 | 1160 | for (i = 0; i < gimple_phi_num_args (stmt); i++) |
0a39fd54 | 1161 | { |
75a70cf9 | 1162 | tree rhs = gimple_phi_arg (stmt, i)->def; |
0a39fd54 | 1163 | |
1164 | if (TREE_CODE (rhs) == SSA_NAME) | |
1165 | check_for_plus_in_loops_1 (osi, rhs, depth); | |
1166 | } | |
1167 | break; | |
1168 | } | |
75a70cf9 | 1169 | |
0a39fd54 | 1170 | default: |
1171 | gcc_unreachable (); | |
1172 | } | |
1173 | ||
1174 | osi->depths[varno] = 0; | |
1175 | osi->tos--; | |
1176 | } | |
1177 | ||
1178 | ||
1179 | /* Check if some pointer we are computing object size of is being increased | |
1180 | within a loop. If yes, assume all the SSA variables participating in | |
1181 | that loop have minimum object sizes 0. */ | |
1182 | ||
1183 | static void | |
1184 | check_for_plus_in_loops (struct object_size_info *osi, tree var) | |
1185 | { | |
42acab1c | 1186 | gimple *stmt = SSA_NAME_DEF_STMT (var); |
0a39fd54 | 1187 | |
75a70cf9 | 1188 | /* NOTE: In the pre-tuples code, we handled a CALL_EXPR here, |
1189 | and looked for a POINTER_PLUS_EXPR in the pass-through | |
1190 | argument, if any. In GIMPLE, however, such an expression | |
1191 | is not a valid call operand. */ | |
0a39fd54 | 1192 | |
75a70cf9 | 1193 | if (is_gimple_assign (stmt) |
1194 | && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) | |
1195 | { | |
1196 | tree basevar = gimple_assign_rhs1 (stmt); | |
1197 | tree cst = gimple_assign_rhs2 (stmt); | |
48e1416a | 1198 | |
75a70cf9 | 1199 | gcc_assert (TREE_CODE (cst) == INTEGER_CST); |
1200 | ||
1201 | if (integer_zerop (cst)) | |
1202 | return; | |
1203 | ||
1204 | osi->depths[SSA_NAME_VERSION (basevar)] = 1; | |
1205 | *osi->tos++ = SSA_NAME_VERSION (basevar); | |
1206 | check_for_plus_in_loops_1 (osi, var, 2); | |
1207 | osi->depths[SSA_NAME_VERSION (basevar)] = 0; | |
1208 | osi->tos--; | |
0a39fd54 | 1209 | } |
1210 | } | |
1211 | ||
1212 | ||
1213 | /* Initialize data structures for the object size computation. */ | |
1214 | ||
1215 | void | |
1216 | init_object_sizes (void) | |
1217 | { | |
1218 | int object_size_type; | |
1219 | ||
194eb161 | 1220 | if (computed[0]) |
0a39fd54 | 1221 | return; |
1222 | ||
1223 | for (object_size_type = 0; object_size_type <= 3; object_size_type++) | |
1224 | { | |
194eb161 | 1225 | object_sizes[object_size_type].safe_grow (num_ssa_names); |
0a39fd54 | 1226 | computed[object_size_type] = BITMAP_ALLOC (NULL); |
1227 | } | |
1228 | ||
1229 | init_offset_limit (); | |
1230 | } | |
1231 | ||
1232 | ||
1233 | /* Destroy data structures after the object size computation. */ | |
1234 | ||
d17f89dd | 1235 | void |
0a39fd54 | 1236 | fini_object_sizes (void) |
1237 | { | |
1238 | int object_size_type; | |
1239 | ||
1240 | for (object_size_type = 0; object_size_type <= 3; object_size_type++) | |
1241 | { | |
194eb161 | 1242 | object_sizes[object_size_type].release (); |
0a39fd54 | 1243 | BITMAP_FREE (computed[object_size_type]); |
0a39fd54 | 1244 | } |
1245 | } | |
1246 | ||
1247 | ||
1248 | /* Simple pass to optimize all __builtin_object_size () builtins. */ | |
1249 | ||
65b0537f | 1250 | namespace { |
1251 | ||
1252 | const pass_data pass_data_object_sizes = | |
1253 | { | |
1254 | GIMPLE_PASS, /* type */ | |
1255 | "objsz", /* name */ | |
1256 | OPTGROUP_NONE, /* optinfo_flags */ | |
65b0537f | 1257 | TV_NONE, /* tv_id */ |
1258 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1259 | 0, /* properties_provided */ | |
1260 | 0, /* properties_destroyed */ | |
1261 | 0, /* todo_flags_start */ | |
8b88439e | 1262 | 0, /* todo_flags_finish */ |
65b0537f | 1263 | }; |
1264 | ||
1265 | class pass_object_sizes : public gimple_opt_pass | |
1266 | { | |
1267 | public: | |
1268 | pass_object_sizes (gcc::context *ctxt) | |
0bb8a43b | 1269 | : gimple_opt_pass (pass_data_object_sizes, ctxt), insert_min_max_p (false) |
65b0537f | 1270 | {} |
1271 | ||
1272 | /* opt_pass methods: */ | |
1273 | opt_pass * clone () { return new pass_object_sizes (m_ctxt); } | |
0bb8a43b | 1274 | void set_pass_param (unsigned int n, bool param) |
1275 | { | |
1276 | gcc_assert (n == 0); | |
1277 | insert_min_max_p = param; | |
1278 | } | |
65b0537f | 1279 | virtual unsigned int execute (function *); |
1280 | ||
0bb8a43b | 1281 | private: |
1282 | /* Determines whether the pass instance creates MIN/MAX_EXPRs. */ | |
1283 | bool insert_min_max_p; | |
65b0537f | 1284 | }; // class pass_object_sizes |
1285 | ||
1603b4dc | 1286 | /* Dummy valueize function. */ |
1287 | ||
1288 | static tree | |
1289 | do_valueize (tree t) | |
1290 | { | |
1291 | return t; | |
1292 | } | |
1293 | ||
65b0537f | 1294 | unsigned int |
1295 | pass_object_sizes::execute (function *fun) | |
0a39fd54 | 1296 | { |
1297 | basic_block bb; | |
65b0537f | 1298 | FOR_EACH_BB_FN (bb, fun) |
0a39fd54 | 1299 | { |
75a70cf9 | 1300 | gimple_stmt_iterator i; |
1301 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) | |
0a39fd54 | 1302 | { |
6a00bf6b | 1303 | tree result; |
42acab1c | 1304 | gimple *call = gsi_stmt (i); |
6a00bf6b | 1305 | if (!gimple_call_builtin_p (call, BUILT_IN_OBJECT_SIZE)) |
0a39fd54 | 1306 | continue; |
1307 | ||
1308 | init_object_sizes (); | |
ece434d4 | 1309 | |
0bb8a43b | 1310 | /* If insert_min_max_p, only attempt to fold |
ece434d4 | 1311 | __builtin_object_size (x, 1) and __builtin_object_size (x, 3), |
1312 | and rather than folding the builtin to the constant if any, | |
1313 | create a MIN_EXPR or MAX_EXPR of the __builtin_object_size | |
1314 | call result and the computed constant. */ | |
0bb8a43b | 1315 | if (insert_min_max_p) |
ece434d4 | 1316 | { |
1317 | tree ost = gimple_call_arg (call, 1); | |
1318 | if (tree_fits_uhwi_p (ost)) | |
1319 | { | |
1320 | unsigned HOST_WIDE_INT object_size_type = tree_to_uhwi (ost); | |
1321 | tree ptr = gimple_call_arg (call, 0); | |
1322 | tree lhs = gimple_call_lhs (call); | |
1323 | if ((object_size_type == 1 || object_size_type == 3) | |
1324 | && (TREE_CODE (ptr) == ADDR_EXPR | |
1325 | || TREE_CODE (ptr) == SSA_NAME) | |
1326 | && lhs) | |
1327 | { | |
1328 | tree type = TREE_TYPE (lhs); | |
4e91a07b | 1329 | unsigned HOST_WIDE_INT bytes; |
1330 | if (compute_builtin_object_size (ptr, object_size_type, | |
1331 | &bytes) | |
ece434d4 | 1332 | && wi::fits_to_tree_p (bytes, type)) |
1333 | { | |
1334 | tree tem = make_ssa_name (type); | |
1335 | gimple_call_set_lhs (call, tem); | |
1336 | enum tree_code code | |
1337 | = object_size_type == 1 ? MIN_EXPR : MAX_EXPR; | |
1338 | tree cst = build_int_cstu (type, bytes); | |
42acab1c | 1339 | gimple *g |
1340 | = gimple_build_assign (lhs, code, tem, cst); | |
ece434d4 | 1341 | gsi_insert_after (&i, g, GSI_NEW_STMT); |
1342 | update_stmt (call); | |
1343 | } | |
1344 | } | |
1345 | } | |
1346 | continue; | |
1347 | } | |
1348 | ||
1603b4dc | 1349 | tree lhs = gimple_call_lhs (call); |
1350 | if (!lhs) | |
1351 | continue; | |
1352 | ||
1353 | result = gimple_fold_stmt_to_constant (call, do_valueize); | |
0a39fd54 | 1354 | if (!result) |
1355 | { | |
ece434d4 | 1356 | tree ost = gimple_call_arg (call, 1); |
1357 | ||
1358 | if (tree_fits_uhwi_p (ost)) | |
0a39fd54 | 1359 | { |
ece434d4 | 1360 | unsigned HOST_WIDE_INT object_size_type = tree_to_uhwi (ost); |
0a39fd54 | 1361 | |
ece434d4 | 1362 | if (object_size_type < 2) |
1363 | result = fold_convert (size_type_node, | |
1364 | integer_minus_one_node); | |
1365 | else if (object_size_type < 4) | |
1366 | result = build_zero_cst (size_type_node); | |
0a39fd54 | 1367 | } |
1368 | ||
1369 | if (!result) | |
1370 | continue; | |
1371 | } | |
1372 | ||
6a00bf6b | 1373 | gcc_assert (TREE_CODE (result) == INTEGER_CST); |
1374 | ||
0a39fd54 | 1375 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1376 | { | |
1377 | fprintf (dump_file, "Simplified\n "); | |
75a70cf9 | 1378 | print_gimple_stmt (dump_file, call, 0, dump_flags); |
6a00bf6b | 1379 | fprintf (dump_file, " to "); |
1ffa4346 | 1380 | print_generic_expr (dump_file, result); |
6a00bf6b | 1381 | fprintf (dump_file, "\n"); |
0a39fd54 | 1382 | } |
1383 | ||
6a00bf6b | 1384 | /* Propagate into all uses and fold those stmts. */ |
1603b4dc | 1385 | replace_uses_by (lhs, result); |
0a39fd54 | 1386 | } |
1387 | } | |
1388 | ||
1389 | fini_object_sizes (); | |
2a1990e9 | 1390 | return 0; |
0a39fd54 | 1391 | } |
1392 | ||
cbe8bda8 | 1393 | } // anon namespace |
1394 | ||
1395 | gimple_opt_pass * | |
1396 | make_pass_object_sizes (gcc::context *ctxt) | |
1397 | { | |
1398 | return new pass_object_sizes (ctxt); | |
1399 | } |