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10a0d495 | 1 | /* __builtin_object_size (ptr, object_size_type) computation |
d1e082c2 | 2 | Copyright (C) 2004-2013 Free Software Foundation, Inc. |
10a0d495 JJ |
3 | Contributed by Jakub Jelinek <jakub@redhat.com> |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9dcd6f09 | 9 | the Free Software Foundation; either version 3, or (at your option) |
10a0d495 JJ |
10 | any later version. |
11 | ||
12 | GCC is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
10a0d495 JJ |
20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
24 | #include "tm.h" | |
25 | #include "tree.h" | |
718f9c0f | 26 | #include "diagnostic-core.h" |
cf835838 | 27 | #include "gimple-pretty-print.h" |
10a0d495 JJ |
28 | #include "tree-flow.h" |
29 | #include "tree-pass.h" | |
30 | #include "tree-ssa-propagate.h" | |
31 | ||
32 | struct object_size_info | |
33 | { | |
34 | int object_size_type; | |
35 | bitmap visited, reexamine; | |
36 | int pass; | |
37 | bool changed; | |
38 | unsigned int *depths; | |
39 | unsigned int *stack, *tos; | |
40 | }; | |
41 | ||
4cdce1a8 | 42 | static const unsigned HOST_WIDE_INT unknown[4] = { -1, -1, 0, 0 }; |
10a0d495 | 43 | |
ac545c64 | 44 | static tree compute_object_offset (const_tree, const_tree); |
eb9ed98a JJ |
45 | static unsigned HOST_WIDE_INT addr_object_size (struct object_size_info *, |
46 | const_tree, int); | |
726a989a RB |
47 | static unsigned HOST_WIDE_INT alloc_object_size (const_gimple, int); |
48 | static tree pass_through_call (const_gimple); | |
10a0d495 JJ |
49 | static void collect_object_sizes_for (struct object_size_info *, tree); |
50 | static void expr_object_size (struct object_size_info *, tree, tree); | |
51 | static bool merge_object_sizes (struct object_size_info *, tree, tree, | |
52 | unsigned HOST_WIDE_INT); | |
726a989a | 53 | static bool plus_stmt_object_size (struct object_size_info *, tree, gimple); |
4e71066d | 54 | static bool cond_expr_object_size (struct object_size_info *, tree, gimple); |
c2924966 | 55 | static unsigned int compute_object_sizes (void); |
10a0d495 JJ |
56 | static void init_offset_limit (void); |
57 | static void check_for_plus_in_loops (struct object_size_info *, tree); | |
58 | static void check_for_plus_in_loops_1 (struct object_size_info *, tree, | |
59 | unsigned int); | |
60 | ||
61 | /* object_sizes[0] is upper bound for number of bytes till the end of | |
62 | the object. | |
63 | object_sizes[1] is upper bound for number of bytes till the end of | |
64 | the subobject (innermost array or field with address taken). | |
65 | object_sizes[2] is lower bound for number of bytes till the end of | |
66 | the object and object_sizes[3] lower bound for subobject. */ | |
67 | static unsigned HOST_WIDE_INT *object_sizes[4]; | |
68 | ||
69 | /* Bitmaps what object sizes have been computed already. */ | |
70 | static bitmap computed[4]; | |
71 | ||
72 | /* Maximum value of offset we consider to be addition. */ | |
73 | static unsigned HOST_WIDE_INT offset_limit; | |
74 | ||
75 | ||
76 | /* Initialize OFFSET_LIMIT variable. */ | |
77 | static void | |
78 | init_offset_limit (void) | |
79 | { | |
80 | if (host_integerp (TYPE_MAX_VALUE (sizetype), 1)) | |
81 | offset_limit = tree_low_cst (TYPE_MAX_VALUE (sizetype), 1); | |
82 | else | |
83 | offset_limit = -1; | |
84 | offset_limit /= 2; | |
85 | } | |
86 | ||
87 | ||
88 | /* Compute offset of EXPR within VAR. Return error_mark_node | |
89 | if unknown. */ | |
90 | ||
91 | static tree | |
ac545c64 | 92 | compute_object_offset (const_tree expr, const_tree var) |
10a0d495 JJ |
93 | { |
94 | enum tree_code code = PLUS_EXPR; | |
95 | tree base, off, t; | |
96 | ||
97 | if (expr == var) | |
98 | return size_zero_node; | |
99 | ||
100 | switch (TREE_CODE (expr)) | |
101 | { | |
102 | case COMPONENT_REF: | |
103 | base = compute_object_offset (TREE_OPERAND (expr, 0), var); | |
104 | if (base == error_mark_node) | |
105 | return base; | |
106 | ||
107 | t = TREE_OPERAND (expr, 1); | |
108 | off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t), | |
109 | size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1) | |
110 | / BITS_PER_UNIT)); | |
111 | break; | |
112 | ||
113 | case REALPART_EXPR: | |
1043771b | 114 | CASE_CONVERT: |
10a0d495 JJ |
115 | case VIEW_CONVERT_EXPR: |
116 | case NON_LVALUE_EXPR: | |
117 | return compute_object_offset (TREE_OPERAND (expr, 0), var); | |
118 | ||
119 | case IMAGPART_EXPR: | |
120 | base = compute_object_offset (TREE_OPERAND (expr, 0), var); | |
121 | if (base == error_mark_node) | |
122 | return base; | |
123 | ||
124 | off = TYPE_SIZE_UNIT (TREE_TYPE (expr)); | |
125 | break; | |
126 | ||
127 | case ARRAY_REF: | |
128 | base = compute_object_offset (TREE_OPERAND (expr, 0), var); | |
129 | if (base == error_mark_node) | |
130 | return base; | |
131 | ||
132 | t = TREE_OPERAND (expr, 1); | |
133 | if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0) | |
134 | { | |
135 | code = MINUS_EXPR; | |
136 | t = fold_build1 (NEGATE_EXPR, TREE_TYPE (t), t); | |
137 | } | |
b6f65e3c | 138 | t = fold_convert (sizetype, t); |
10a0d495 JJ |
139 | off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t); |
140 | break; | |
141 | ||
70f34814 RG |
142 | case MEM_REF: |
143 | gcc_assert (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR); | |
f8bce518 | 144 | return double_int_to_tree (sizetype, mem_ref_offset (expr)); |
70f34814 | 145 | |
10a0d495 JJ |
146 | default: |
147 | return error_mark_node; | |
148 | } | |
149 | ||
150 | return size_binop (code, base, off); | |
151 | } | |
152 | ||
153 | ||
154 | /* Compute __builtin_object_size for PTR, which is a ADDR_EXPR. | |
155 | OBJECT_SIZE_TYPE is the second argument from __builtin_object_size. | |
156 | If unknown, return unknown[object_size_type]. */ | |
157 | ||
158 | static unsigned HOST_WIDE_INT | |
eb9ed98a JJ |
159 | addr_object_size (struct object_size_info *osi, const_tree ptr, |
160 | int object_size_type) | |
10a0d495 | 161 | { |
eb9ed98a | 162 | tree pt_var, pt_var_size = NULL_TREE, var_size, bytes; |
10a0d495 JJ |
163 | |
164 | gcc_assert (TREE_CODE (ptr) == ADDR_EXPR); | |
165 | ||
166 | pt_var = TREE_OPERAND (ptr, 0); | |
d837d73d RG |
167 | while (handled_component_p (pt_var)) |
168 | pt_var = TREE_OPERAND (pt_var, 0); | |
10a0d495 JJ |
169 | |
170 | if (pt_var | |
d837d73d | 171 | && TREE_CODE (pt_var) == MEM_REF) |
10a0d495 | 172 | { |
eb9ed98a | 173 | unsigned HOST_WIDE_INT sz; |
10a0d495 | 174 | |
d837d73d | 175 | if (!osi || (object_size_type & 1) != 0 |
ea17de23 | 176 | || TREE_CODE (TREE_OPERAND (pt_var, 0)) != SSA_NAME) |
70f34814 RG |
177 | { |
178 | sz = compute_builtin_object_size (TREE_OPERAND (pt_var, 0), | |
179 | object_size_type & ~1); | |
70f34814 | 180 | } |
eb9ed98a | 181 | else |
10a0d495 | 182 | { |
eb9ed98a JJ |
183 | tree var = TREE_OPERAND (pt_var, 0); |
184 | if (osi->pass == 0) | |
185 | collect_object_sizes_for (osi, var); | |
186 | if (bitmap_bit_p (computed[object_size_type], | |
187 | SSA_NAME_VERSION (var))) | |
188 | sz = object_sizes[object_size_type][SSA_NAME_VERSION (var)]; | |
189 | else | |
190 | sz = unknown[object_size_type]; | |
d837d73d RG |
191 | } |
192 | if (sz != unknown[object_size_type]) | |
193 | { | |
27bcd47c LC |
194 | double_int dsz = double_int::from_uhwi (sz) - mem_ref_offset (pt_var); |
195 | if (dsz.is_negative ()) | |
d837d73d | 196 | sz = 0; |
27bcd47c LC |
197 | else if (dsz.fits_uhwi ()) |
198 | sz = dsz.to_uhwi (); | |
70f34814 | 199 | else |
d837d73d | 200 | sz = unknown[object_size_type]; |
eb9ed98a JJ |
201 | } |
202 | ||
203 | if (sz != unknown[object_size_type] && sz < offset_limit) | |
204 | pt_var_size = size_int (sz); | |
205 | } | |
e497b9bd RG |
206 | else if (pt_var |
207 | && DECL_P (pt_var) | |
208 | && host_integerp (DECL_SIZE_UNIT (pt_var), 1) | |
209 | && (unsigned HOST_WIDE_INT) | |
210 | tree_low_cst (DECL_SIZE_UNIT (pt_var), 1) < offset_limit) | |
211 | pt_var_size = DECL_SIZE_UNIT (pt_var); | |
eb9ed98a | 212 | else if (pt_var |
d837d73d | 213 | && TREE_CODE (pt_var) == STRING_CST |
eb9ed98a JJ |
214 | && TYPE_SIZE_UNIT (TREE_TYPE (pt_var)) |
215 | && host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (pt_var)), 1) | |
216 | && (unsigned HOST_WIDE_INT) | |
217 | tree_low_cst (TYPE_SIZE_UNIT (TREE_TYPE (pt_var)), 1) | |
218 | < offset_limit) | |
219 | pt_var_size = TYPE_SIZE_UNIT (TREE_TYPE (pt_var)); | |
220 | else | |
221 | return unknown[object_size_type]; | |
222 | ||
223 | if (pt_var != TREE_OPERAND (ptr, 0)) | |
224 | { | |
225 | tree var; | |
10a0d495 | 226 | |
eb9ed98a JJ |
227 | if (object_size_type & 1) |
228 | { | |
229 | var = TREE_OPERAND (ptr, 0); | |
230 | ||
231 | while (var != pt_var | |
232 | && TREE_CODE (var) != BIT_FIELD_REF | |
233 | && TREE_CODE (var) != COMPONENT_REF | |
234 | && TREE_CODE (var) != ARRAY_REF | |
235 | && TREE_CODE (var) != ARRAY_RANGE_REF | |
236 | && TREE_CODE (var) != REALPART_EXPR | |
237 | && TREE_CODE (var) != IMAGPART_EXPR) | |
238 | var = TREE_OPERAND (var, 0); | |
239 | if (var != pt_var && TREE_CODE (var) == ARRAY_REF) | |
38027156 | 240 | var = TREE_OPERAND (var, 0); |
eb9ed98a JJ |
241 | if (! TYPE_SIZE_UNIT (TREE_TYPE (var)) |
242 | || ! host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (var)), 1) | |
243 | || (pt_var_size | |
244 | && tree_int_cst_lt (pt_var_size, | |
245 | TYPE_SIZE_UNIT (TREE_TYPE (var))))) | |
246 | var = pt_var; | |
70f34814 | 247 | else if (var != pt_var && TREE_CODE (pt_var) == MEM_REF) |
10a0d495 | 248 | { |
eb9ed98a JJ |
249 | tree v = var; |
250 | /* For &X->fld, compute object size only if fld isn't the last | |
251 | field, as struct { int i; char c[1]; } is often used instead | |
252 | of flexible array member. */ | |
253 | while (v && v != pt_var) | |
254 | switch (TREE_CODE (v)) | |
255 | { | |
256 | case ARRAY_REF: | |
257 | if (TYPE_SIZE_UNIT (TREE_TYPE (TREE_OPERAND (v, 0))) | |
258 | && TREE_CODE (TREE_OPERAND (v, 1)) == INTEGER_CST) | |
259 | { | |
260 | tree domain | |
261 | = TYPE_DOMAIN (TREE_TYPE (TREE_OPERAND (v, 0))); | |
262 | if (domain | |
263 | && TYPE_MAX_VALUE (domain) | |
264 | && TREE_CODE (TYPE_MAX_VALUE (domain)) | |
265 | == INTEGER_CST | |
266 | && tree_int_cst_lt (TREE_OPERAND (v, 1), | |
267 | TYPE_MAX_VALUE (domain))) | |
268 | { | |
269 | v = NULL_TREE; | |
270 | break; | |
271 | } | |
272 | } | |
273 | v = TREE_OPERAND (v, 0); | |
274 | break; | |
275 | case REALPART_EXPR: | |
276 | case IMAGPART_EXPR: | |
277 | v = NULL_TREE; | |
278 | break; | |
279 | case COMPONENT_REF: | |
8593e0b6 JJ |
280 | if (TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE) |
281 | { | |
282 | v = NULL_TREE; | |
283 | break; | |
284 | } | |
38027156 JJ |
285 | while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) |
286 | if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
287 | != UNION_TYPE | |
288 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
289 | != QUAL_UNION_TYPE) | |
290 | break; | |
291 | else | |
292 | v = TREE_OPERAND (v, 0); | |
293 | if (TREE_CODE (v) == COMPONENT_REF | |
294 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
295 | == RECORD_TYPE) | |
eb9ed98a | 296 | { |
910ad8de NF |
297 | tree fld_chain = DECL_CHAIN (TREE_OPERAND (v, 1)); |
298 | for (; fld_chain; fld_chain = DECL_CHAIN (fld_chain)) | |
8593e0b6 JJ |
299 | if (TREE_CODE (fld_chain) == FIELD_DECL) |
300 | break; | |
301 | ||
302 | if (fld_chain) | |
303 | { | |
304 | v = NULL_TREE; | |
eb9ed98a | 305 | break; |
8593e0b6 | 306 | } |
38027156 | 307 | v = TREE_OPERAND (v, 0); |
eb9ed98a | 308 | } |
38027156 JJ |
309 | while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) |
310 | if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
311 | != UNION_TYPE | |
312 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) | |
313 | != QUAL_UNION_TYPE) | |
8593e0b6 JJ |
314 | break; |
315 | else | |
316 | v = TREE_OPERAND (v, 0); | |
38027156 | 317 | if (v != pt_var) |
8593e0b6 JJ |
318 | v = NULL_TREE; |
319 | else | |
320 | v = pt_var; | |
eb9ed98a JJ |
321 | break; |
322 | default: | |
323 | v = pt_var; | |
324 | break; | |
325 | } | |
326 | if (v == pt_var) | |
10a0d495 JJ |
327 | var = pt_var; |
328 | } | |
eb9ed98a JJ |
329 | } |
330 | else | |
331 | var = pt_var; | |
10a0d495 | 332 | |
eb9ed98a JJ |
333 | if (var != pt_var) |
334 | var_size = TYPE_SIZE_UNIT (TREE_TYPE (var)); | |
335 | else if (!pt_var_size) | |
336 | return unknown[object_size_type]; | |
337 | else | |
338 | var_size = pt_var_size; | |
339 | bytes = compute_object_offset (TREE_OPERAND (ptr, 0), var); | |
340 | if (bytes != error_mark_node) | |
341 | { | |
342 | if (TREE_CODE (bytes) == INTEGER_CST | |
343 | && tree_int_cst_lt (var_size, bytes)) | |
344 | bytes = size_zero_node; | |
345 | else | |
346 | bytes = size_binop (MINUS_EXPR, var_size, bytes); | |
347 | } | |
348 | if (var != pt_var | |
349 | && pt_var_size | |
70f34814 | 350 | && TREE_CODE (pt_var) == MEM_REF |
eb9ed98a JJ |
351 | && bytes != error_mark_node) |
352 | { | |
353 | tree bytes2 = compute_object_offset (TREE_OPERAND (ptr, 0), pt_var); | |
354 | if (bytes2 != error_mark_node) | |
10a0d495 | 355 | { |
eb9ed98a JJ |
356 | if (TREE_CODE (bytes2) == INTEGER_CST |
357 | && tree_int_cst_lt (pt_var_size, bytes2)) | |
358 | bytes2 = size_zero_node; | |
10a0d495 | 359 | else |
98a129b9 | 360 | bytes2 = size_binop (MINUS_EXPR, pt_var_size, bytes2); |
eb9ed98a | 361 | bytes = size_binop (MIN_EXPR, bytes, bytes2); |
10a0d495 JJ |
362 | } |
363 | } | |
10a0d495 | 364 | } |
eb9ed98a JJ |
365 | else if (!pt_var_size) |
366 | return unknown[object_size_type]; | |
367 | else | |
368 | bytes = pt_var_size; | |
369 | ||
370 | if (host_integerp (bytes, 1)) | |
371 | return tree_low_cst (bytes, 1); | |
10a0d495 JJ |
372 | |
373 | return unknown[object_size_type]; | |
374 | } | |
375 | ||
376 | ||
726a989a | 377 | /* Compute __builtin_object_size for CALL, which is a GIMPLE_CALL. |
10a0d495 JJ |
378 | Handles various allocation calls. OBJECT_SIZE_TYPE is the second |
379 | argument from __builtin_object_size. If unknown, return | |
380 | unknown[object_size_type]. */ | |
381 | ||
382 | static unsigned HOST_WIDE_INT | |
726a989a | 383 | alloc_object_size (const_gimple call, int object_size_type) |
10a0d495 | 384 | { |
5039610b | 385 | tree callee, bytes = NULL_TREE; |
51bc54a6 DM |
386 | tree alloc_size; |
387 | int arg1 = -1, arg2 = -1; | |
10a0d495 | 388 | |
726a989a | 389 | gcc_assert (is_gimple_call (call)); |
10a0d495 | 390 | |
726a989a | 391 | callee = gimple_call_fndecl (call); |
51bc54a6 DM |
392 | if (!callee) |
393 | return unknown[object_size_type]; | |
394 | ||
395 | alloc_size = lookup_attribute ("alloc_size", TYPE_ATTRIBUTES (TREE_TYPE(callee))); | |
396 | if (alloc_size && TREE_VALUE (alloc_size)) | |
397 | { | |
398 | tree p = TREE_VALUE (alloc_size); | |
399 | ||
400 | arg1 = TREE_INT_CST_LOW (TREE_VALUE (p))-1; | |
401 | if (TREE_CHAIN (p)) | |
726a989a | 402 | arg2 = TREE_INT_CST_LOW (TREE_VALUE (TREE_CHAIN (p)))-1; |
51bc54a6 | 403 | } |
b8698a0f | 404 | |
51bc54a6 | 405 | if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) |
10a0d495 JJ |
406 | switch (DECL_FUNCTION_CODE (callee)) |
407 | { | |
51bc54a6 DM |
408 | case BUILT_IN_CALLOC: |
409 | arg2 = 1; | |
410 | /* fall through */ | |
10a0d495 JJ |
411 | case BUILT_IN_MALLOC: |
412 | case BUILT_IN_ALLOCA: | |
13e49da9 | 413 | case BUILT_IN_ALLOCA_WITH_ALIGN: |
51bc54a6 | 414 | arg1 = 0; |
10a0d495 JJ |
415 | default: |
416 | break; | |
417 | } | |
418 | ||
726a989a RB |
419 | if (arg1 < 0 || arg1 >= (int)gimple_call_num_args (call) |
420 | || TREE_CODE (gimple_call_arg (call, arg1)) != INTEGER_CST | |
b8698a0f | 421 | || (arg2 >= 0 |
726a989a RB |
422 | && (arg2 >= (int)gimple_call_num_args (call) |
423 | || TREE_CODE (gimple_call_arg (call, arg2)) != INTEGER_CST))) | |
b8698a0f | 424 | return unknown[object_size_type]; |
51bc54a6 DM |
425 | |
426 | if (arg2 >= 0) | |
427 | bytes = size_binop (MULT_EXPR, | |
726a989a RB |
428 | fold_convert (sizetype, gimple_call_arg (call, arg1)), |
429 | fold_convert (sizetype, gimple_call_arg (call, arg2))); | |
51bc54a6 | 430 | else if (arg1 >= 0) |
726a989a | 431 | bytes = fold_convert (sizetype, gimple_call_arg (call, arg1)); |
51bc54a6 | 432 | |
5039610b | 433 | if (bytes && host_integerp (bytes, 1)) |
10a0d495 JJ |
434 | return tree_low_cst (bytes, 1); |
435 | ||
436 | return unknown[object_size_type]; | |
437 | } | |
438 | ||
439 | ||
440 | /* If object size is propagated from one of function's arguments directly | |
726a989a | 441 | to its return value, return that argument for GIMPLE_CALL statement CALL. |
10a0d495 JJ |
442 | Otherwise return NULL. */ |
443 | ||
444 | static tree | |
726a989a | 445 | pass_through_call (const_gimple call) |
10a0d495 | 446 | { |
726a989a | 447 | tree callee = gimple_call_fndecl (call); |
10a0d495 JJ |
448 | |
449 | if (callee | |
450 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) | |
451 | switch (DECL_FUNCTION_CODE (callee)) | |
452 | { | |
453 | case BUILT_IN_MEMCPY: | |
454 | case BUILT_IN_MEMMOVE: | |
455 | case BUILT_IN_MEMSET: | |
456 | case BUILT_IN_STRCPY: | |
457 | case BUILT_IN_STRNCPY: | |
458 | case BUILT_IN_STRCAT: | |
459 | case BUILT_IN_STRNCAT: | |
460 | case BUILT_IN_MEMCPY_CHK: | |
461 | case BUILT_IN_MEMMOVE_CHK: | |
462 | case BUILT_IN_MEMSET_CHK: | |
463 | case BUILT_IN_STRCPY_CHK: | |
464 | case BUILT_IN_STRNCPY_CHK: | |
f3fc9b80 | 465 | case BUILT_IN_STPNCPY_CHK: |
10a0d495 JJ |
466 | case BUILT_IN_STRCAT_CHK: |
467 | case BUILT_IN_STRNCAT_CHK: | |
8b1bdcc5 | 468 | case BUILT_IN_ASSUME_ALIGNED: |
726a989a RB |
469 | if (gimple_call_num_args (call) >= 1) |
470 | return gimple_call_arg (call, 0); | |
10a0d495 JJ |
471 | break; |
472 | default: | |
473 | break; | |
474 | } | |
475 | ||
476 | return NULL_TREE; | |
477 | } | |
478 | ||
479 | ||
480 | /* Compute __builtin_object_size value for PTR. OBJECT_SIZE_TYPE is the | |
481 | second argument from __builtin_object_size. */ | |
482 | ||
483 | unsigned HOST_WIDE_INT | |
484 | compute_builtin_object_size (tree ptr, int object_size_type) | |
485 | { | |
486 | gcc_assert (object_size_type >= 0 && object_size_type <= 3); | |
487 | ||
488 | if (! offset_limit) | |
489 | init_offset_limit (); | |
490 | ||
491 | if (TREE_CODE (ptr) == ADDR_EXPR) | |
eb9ed98a | 492 | return addr_object_size (NULL, ptr, object_size_type); |
10a0d495 | 493 | |
726a989a | 494 | if (TREE_CODE (ptr) == SSA_NAME |
eb9ed98a JJ |
495 | && POINTER_TYPE_P (TREE_TYPE (ptr)) |
496 | && object_sizes[object_size_type] != NULL) | |
10a0d495 JJ |
497 | { |
498 | if (!bitmap_bit_p (computed[object_size_type], SSA_NAME_VERSION (ptr))) | |
499 | { | |
500 | struct object_size_info osi; | |
501 | bitmap_iterator bi; | |
502 | unsigned int i; | |
503 | ||
504 | if (dump_file) | |
505 | { | |
506 | fprintf (dump_file, "Computing %s %sobject size for ", | |
507 | (object_size_type & 2) ? "minimum" : "maximum", | |
508 | (object_size_type & 1) ? "sub" : ""); | |
509 | print_generic_expr (dump_file, ptr, dump_flags); | |
510 | fprintf (dump_file, ":\n"); | |
511 | } | |
512 | ||
513 | osi.visited = BITMAP_ALLOC (NULL); | |
514 | osi.reexamine = BITMAP_ALLOC (NULL); | |
515 | osi.object_size_type = object_size_type; | |
516 | osi.depths = NULL; | |
517 | osi.stack = NULL; | |
518 | osi.tos = NULL; | |
519 | ||
520 | /* First pass: walk UD chains, compute object sizes that | |
521 | can be computed. osi.reexamine bitmap at the end will | |
522 | contain what variables were found in dependency cycles | |
523 | and therefore need to be reexamined. */ | |
524 | osi.pass = 0; | |
525 | osi.changed = false; | |
526 | collect_object_sizes_for (&osi, ptr); | |
527 | ||
528 | /* Second pass: keep recomputing object sizes of variables | |
529 | that need reexamination, until no object sizes are | |
530 | increased or all object sizes are computed. */ | |
531 | if (! bitmap_empty_p (osi.reexamine)) | |
532 | { | |
533 | bitmap reexamine = BITMAP_ALLOC (NULL); | |
534 | ||
535 | /* If looking for minimum instead of maximum object size, | |
536 | detect cases where a pointer is increased in a loop. | |
537 | Although even without this detection pass 2 would eventually | |
538 | terminate, it could take a long time. If a pointer is | |
539 | increasing this way, we need to assume 0 object size. | |
540 | E.g. p = &buf[0]; while (cond) p = p + 4; */ | |
541 | if (object_size_type & 2) | |
542 | { | |
5ed6ace5 MD |
543 | osi.depths = XCNEWVEC (unsigned int, num_ssa_names); |
544 | osi.stack = XNEWVEC (unsigned int, num_ssa_names); | |
10a0d495 JJ |
545 | osi.tos = osi.stack; |
546 | osi.pass = 1; | |
547 | /* collect_object_sizes_for is changing | |
548 | osi.reexamine bitmap, so iterate over a copy. */ | |
549 | bitmap_copy (reexamine, osi.reexamine); | |
550 | EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi) | |
551 | if (bitmap_bit_p (osi.reexamine, i)) | |
552 | check_for_plus_in_loops (&osi, ssa_name (i)); | |
553 | ||
554 | free (osi.depths); | |
555 | osi.depths = NULL; | |
556 | free (osi.stack); | |
557 | osi.stack = NULL; | |
558 | osi.tos = NULL; | |
559 | } | |
560 | ||
561 | do | |
562 | { | |
563 | osi.pass = 2; | |
564 | osi.changed = false; | |
565 | /* collect_object_sizes_for is changing | |
566 | osi.reexamine bitmap, so iterate over a copy. */ | |
567 | bitmap_copy (reexamine, osi.reexamine); | |
568 | EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi) | |
569 | if (bitmap_bit_p (osi.reexamine, i)) | |
570 | { | |
571 | collect_object_sizes_for (&osi, ssa_name (i)); | |
572 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
573 | { | |
574 | fprintf (dump_file, "Reexamining "); | |
575 | print_generic_expr (dump_file, ssa_name (i), | |
576 | dump_flags); | |
577 | fprintf (dump_file, "\n"); | |
578 | } | |
579 | } | |
580 | } | |
581 | while (osi.changed); | |
582 | ||
583 | BITMAP_FREE (reexamine); | |
584 | } | |
585 | EXECUTE_IF_SET_IN_BITMAP (osi.reexamine, 0, i, bi) | |
586 | bitmap_set_bit (computed[object_size_type], i); | |
587 | ||
588 | /* Debugging dumps. */ | |
589 | if (dump_file) | |
590 | { | |
591 | EXECUTE_IF_SET_IN_BITMAP (osi.visited, 0, i, bi) | |
592 | if (object_sizes[object_size_type][i] | |
593 | != unknown[object_size_type]) | |
594 | { | |
595 | print_generic_expr (dump_file, ssa_name (i), | |
596 | dump_flags); | |
597 | fprintf (dump_file, | |
598 | ": %s %sobject size " | |
599 | HOST_WIDE_INT_PRINT_UNSIGNED "\n", | |
600 | (object_size_type & 2) ? "minimum" : "maximum", | |
601 | (object_size_type & 1) ? "sub" : "", | |
602 | object_sizes[object_size_type][i]); | |
603 | } | |
604 | } | |
605 | ||
606 | BITMAP_FREE (osi.reexamine); | |
607 | BITMAP_FREE (osi.visited); | |
608 | } | |
609 | ||
610 | return object_sizes[object_size_type][SSA_NAME_VERSION (ptr)]; | |
611 | } | |
612 | ||
613 | return unknown[object_size_type]; | |
614 | } | |
615 | ||
726a989a | 616 | /* Compute object_sizes for PTR, defined to VALUE, which is not an SSA_NAME. */ |
10a0d495 JJ |
617 | |
618 | static void | |
619 | expr_object_size (struct object_size_info *osi, tree ptr, tree value) | |
620 | { | |
621 | int object_size_type = osi->object_size_type; | |
622 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
623 | unsigned HOST_WIDE_INT bytes; | |
624 | ||
625 | gcc_assert (object_sizes[object_size_type][varno] | |
626 | != unknown[object_size_type]); | |
627 | gcc_assert (osi->pass == 0); | |
628 | ||
629 | if (TREE_CODE (value) == WITH_SIZE_EXPR) | |
630 | value = TREE_OPERAND (value, 0); | |
631 | ||
632 | /* Pointer variables should have been handled by merge_object_sizes. */ | |
633 | gcc_assert (TREE_CODE (value) != SSA_NAME | |
634 | || !POINTER_TYPE_P (TREE_TYPE (value))); | |
635 | ||
636 | if (TREE_CODE (value) == ADDR_EXPR) | |
eb9ed98a | 637 | bytes = addr_object_size (osi, value, object_size_type); |
10a0d495 JJ |
638 | else |
639 | bytes = unknown[object_size_type]; | |
640 | ||
641 | if ((object_size_type & 2) == 0) | |
642 | { | |
643 | if (object_sizes[object_size_type][varno] < bytes) | |
644 | object_sizes[object_size_type][varno] = bytes; | |
645 | } | |
646 | else | |
647 | { | |
648 | if (object_sizes[object_size_type][varno] > bytes) | |
649 | object_sizes[object_size_type][varno] = bytes; | |
650 | } | |
651 | } | |
652 | ||
653 | ||
726a989a RB |
654 | /* Compute object_sizes for PTR, defined to the result of a call. */ |
655 | ||
656 | static void | |
657 | call_object_size (struct object_size_info *osi, tree ptr, gimple call) | |
658 | { | |
659 | int object_size_type = osi->object_size_type; | |
660 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
661 | unsigned HOST_WIDE_INT bytes; | |
662 | ||
663 | gcc_assert (is_gimple_call (call)); | |
664 | ||
665 | gcc_assert (object_sizes[object_size_type][varno] | |
666 | != unknown[object_size_type]); | |
667 | gcc_assert (osi->pass == 0); | |
668 | ||
669 | bytes = alloc_object_size (call, object_size_type); | |
670 | ||
671 | if ((object_size_type & 2) == 0) | |
672 | { | |
673 | if (object_sizes[object_size_type][varno] < bytes) | |
674 | object_sizes[object_size_type][varno] = bytes; | |
675 | } | |
676 | else | |
677 | { | |
678 | if (object_sizes[object_size_type][varno] > bytes) | |
679 | object_sizes[object_size_type][varno] = bytes; | |
680 | } | |
681 | } | |
682 | ||
683 | ||
684 | /* Compute object_sizes for PTR, defined to an unknown value. */ | |
685 | ||
686 | static void | |
687 | unknown_object_size (struct object_size_info *osi, tree ptr) | |
688 | { | |
689 | int object_size_type = osi->object_size_type; | |
690 | unsigned int varno = SSA_NAME_VERSION (ptr); | |
691 | unsigned HOST_WIDE_INT bytes; | |
692 | ||
693 | gcc_assert (object_sizes[object_size_type][varno] | |
694 | != unknown[object_size_type]); | |
695 | gcc_assert (osi->pass == 0); | |
696 | ||
697 | bytes = unknown[object_size_type]; | |
698 | ||
699 | if ((object_size_type & 2) == 0) | |
700 | { | |
701 | if (object_sizes[object_size_type][varno] < bytes) | |
702 | object_sizes[object_size_type][varno] = bytes; | |
703 | } | |
704 | else | |
705 | { | |
706 | if (object_sizes[object_size_type][varno] > bytes) | |
707 | object_sizes[object_size_type][varno] = bytes; | |
708 | } | |
709 | } | |
710 | ||
711 | ||
10a0d495 JJ |
712 | /* Merge object sizes of ORIG + OFFSET into DEST. Return true if |
713 | the object size might need reexamination later. */ | |
714 | ||
715 | static bool | |
716 | merge_object_sizes (struct object_size_info *osi, tree dest, tree orig, | |
717 | unsigned HOST_WIDE_INT offset) | |
718 | { | |
719 | int object_size_type = osi->object_size_type; | |
720 | unsigned int varno = SSA_NAME_VERSION (dest); | |
721 | unsigned HOST_WIDE_INT orig_bytes; | |
722 | ||
723 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
724 | return false; | |
725 | if (offset >= offset_limit) | |
726 | { | |
727 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
728 | return false; | |
729 | } | |
730 | ||
731 | if (osi->pass == 0) | |
732 | collect_object_sizes_for (osi, orig); | |
733 | ||
734 | orig_bytes = object_sizes[object_size_type][SSA_NAME_VERSION (orig)]; | |
735 | if (orig_bytes != unknown[object_size_type]) | |
736 | orig_bytes = (offset > orig_bytes) | |
737 | ? (unsigned HOST_WIDE_INT) 0 : orig_bytes - offset; | |
738 | ||
739 | if ((object_size_type & 2) == 0) | |
740 | { | |
741 | if (object_sizes[object_size_type][varno] < orig_bytes) | |
742 | { | |
743 | object_sizes[object_size_type][varno] = orig_bytes; | |
744 | osi->changed = true; | |
745 | } | |
746 | } | |
747 | else | |
748 | { | |
749 | if (object_sizes[object_size_type][varno] > orig_bytes) | |
750 | { | |
751 | object_sizes[object_size_type][varno] = orig_bytes; | |
752 | osi->changed = true; | |
753 | } | |
754 | } | |
755 | return bitmap_bit_p (osi->reexamine, SSA_NAME_VERSION (orig)); | |
756 | } | |
757 | ||
758 | ||
726a989a RB |
759 | /* Compute object_sizes for VAR, defined to the result of an assignment |
760 | with operator POINTER_PLUS_EXPR. Return true if the object size might | |
761 | need reexamination later. */ | |
10a0d495 JJ |
762 | |
763 | static bool | |
726a989a | 764 | plus_stmt_object_size (struct object_size_info *osi, tree var, gimple stmt) |
10a0d495 | 765 | { |
10a0d495 JJ |
766 | int object_size_type = osi->object_size_type; |
767 | unsigned int varno = SSA_NAME_VERSION (var); | |
768 | unsigned HOST_WIDE_INT bytes; | |
726a989a RB |
769 | tree op0, op1; |
770 | ||
70f34814 RG |
771 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) |
772 | { | |
773 | op0 = gimple_assign_rhs1 (stmt); | |
774 | op1 = gimple_assign_rhs2 (stmt); | |
775 | } | |
776 | else if (gimple_assign_rhs_code (stmt) == ADDR_EXPR) | |
777 | { | |
778 | tree rhs = TREE_OPERAND (gimple_assign_rhs1 (stmt), 0); | |
779 | gcc_assert (TREE_CODE (rhs) == MEM_REF); | |
780 | op0 = TREE_OPERAND (rhs, 0); | |
781 | op1 = TREE_OPERAND (rhs, 1); | |
782 | } | |
783 | else | |
784 | gcc_unreachable (); | |
10a0d495 JJ |
785 | |
786 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
787 | return false; | |
788 | ||
10a0d495 | 789 | /* Handle PTR + OFFSET here. */ |
5be014d5 | 790 | if (TREE_CODE (op1) == INTEGER_CST |
10a0d495 JJ |
791 | && (TREE_CODE (op0) == SSA_NAME |
792 | || TREE_CODE (op0) == ADDR_EXPR)) | |
793 | { | |
794 | if (! host_integerp (op1, 1)) | |
795 | bytes = unknown[object_size_type]; | |
796 | else if (TREE_CODE (op0) == SSA_NAME) | |
797 | return merge_object_sizes (osi, var, op0, tree_low_cst (op1, 1)); | |
798 | else | |
799 | { | |
800 | unsigned HOST_WIDE_INT off = tree_low_cst (op1, 1); | |
801 | ||
726a989a | 802 | /* op0 will be ADDR_EXPR here. */ |
eb9ed98a | 803 | bytes = addr_object_size (osi, op0, object_size_type); |
ac5a28a6 JH |
804 | if (bytes == unknown[object_size_type]) |
805 | ; | |
806 | else if (off > offset_limit) | |
10a0d495 JJ |
807 | bytes = unknown[object_size_type]; |
808 | else if (off > bytes) | |
809 | bytes = 0; | |
810 | else | |
811 | bytes -= off; | |
812 | } | |
813 | } | |
814 | else | |
815 | bytes = unknown[object_size_type]; | |
816 | ||
817 | if ((object_size_type & 2) == 0) | |
818 | { | |
819 | if (object_sizes[object_size_type][varno] < bytes) | |
820 | object_sizes[object_size_type][varno] = bytes; | |
821 | } | |
822 | else | |
823 | { | |
824 | if (object_sizes[object_size_type][varno] > bytes) | |
825 | object_sizes[object_size_type][varno] = bytes; | |
826 | } | |
827 | return false; | |
828 | } | |
829 | ||
830 | ||
4e71066d | 831 | /* Compute object_sizes for VAR, defined at STMT, which is |
f255541f RC |
832 | a COND_EXPR. Return true if the object size might need reexamination |
833 | later. */ | |
834 | ||
835 | static bool | |
4e71066d | 836 | cond_expr_object_size (struct object_size_info *osi, tree var, gimple stmt) |
f255541f RC |
837 | { |
838 | tree then_, else_; | |
839 | int object_size_type = osi->object_size_type; | |
840 | unsigned int varno = SSA_NAME_VERSION (var); | |
841 | bool reexamine = false; | |
842 | ||
4e71066d | 843 | gcc_assert (gimple_assign_rhs_code (stmt) == COND_EXPR); |
f255541f RC |
844 | |
845 | if (object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
846 | return false; | |
847 | ||
4e71066d RG |
848 | then_ = gimple_assign_rhs2 (stmt); |
849 | else_ = gimple_assign_rhs3 (stmt); | |
f255541f RC |
850 | |
851 | if (TREE_CODE (then_) == SSA_NAME) | |
852 | reexamine |= merge_object_sizes (osi, var, then_, 0); | |
853 | else | |
854 | expr_object_size (osi, var, then_); | |
855 | ||
856 | if (TREE_CODE (else_) == SSA_NAME) | |
857 | reexamine |= merge_object_sizes (osi, var, else_, 0); | |
858 | else | |
859 | expr_object_size (osi, var, else_); | |
860 | ||
861 | return reexamine; | |
862 | } | |
863 | ||
10a0d495 JJ |
864 | /* Compute object sizes for VAR. |
865 | For ADDR_EXPR an object size is the number of remaining bytes | |
619519c8 | 866 | to the end of the object (where what is considered an object depends on |
10a0d495 | 867 | OSI->object_size_type). |
726a989a | 868 | For allocation GIMPLE_CALL like malloc or calloc object size is the size |
10a0d495 | 869 | of the allocation. |
5be014d5 | 870 | For POINTER_PLUS_EXPR where second operand is a constant integer, |
10a0d495 JJ |
871 | object size is object size of the first operand minus the constant. |
872 | If the constant is bigger than the number of remaining bytes until the | |
873 | end of the object, object size is 0, but if it is instead a pointer | |
874 | subtraction, object size is unknown[object_size_type]. | |
875 | To differentiate addition from subtraction, ADDR_EXPR returns | |
876 | unknown[object_size_type] for all objects bigger than half of the address | |
877 | space, and constants less than half of the address space are considered | |
878 | addition, while bigger constants subtraction. | |
726a989a | 879 | For a memcpy like GIMPLE_CALL that always returns one of its arguments, the |
10a0d495 JJ |
880 | object size is object size of that argument. |
881 | Otherwise, object size is the maximum of object sizes of variables | |
882 | that it might be set to. */ | |
883 | ||
884 | static void | |
885 | collect_object_sizes_for (struct object_size_info *osi, tree var) | |
886 | { | |
887 | int object_size_type = osi->object_size_type; | |
888 | unsigned int varno = SSA_NAME_VERSION (var); | |
726a989a | 889 | gimple stmt; |
10a0d495 JJ |
890 | bool reexamine; |
891 | ||
892 | if (bitmap_bit_p (computed[object_size_type], varno)) | |
893 | return; | |
894 | ||
895 | if (osi->pass == 0) | |
896 | { | |
fcaa4ca4 | 897 | if (bitmap_set_bit (osi->visited, varno)) |
10a0d495 | 898 | { |
10a0d495 JJ |
899 | object_sizes[object_size_type][varno] |
900 | = (object_size_type & 2) ? -1 : 0; | |
901 | } | |
902 | else | |
903 | { | |
904 | /* Found a dependency loop. Mark the variable for later | |
905 | re-examination. */ | |
906 | bitmap_set_bit (osi->reexamine, varno); | |
907 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
908 | { | |
909 | fprintf (dump_file, "Found a dependency loop at "); | |
910 | print_generic_expr (dump_file, var, dump_flags); | |
911 | fprintf (dump_file, "\n"); | |
912 | } | |
913 | return; | |
914 | } | |
915 | } | |
916 | ||
917 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
918 | { | |
919 | fprintf (dump_file, "Visiting use-def links for "); | |
920 | print_generic_expr (dump_file, var, dump_flags); | |
921 | fprintf (dump_file, "\n"); | |
922 | } | |
923 | ||
924 | stmt = SSA_NAME_DEF_STMT (var); | |
925 | reexamine = false; | |
926 | ||
726a989a | 927 | switch (gimple_code (stmt)) |
10a0d495 | 928 | { |
726a989a | 929 | case GIMPLE_ASSIGN: |
10a0d495 | 930 | { |
70f34814 RG |
931 | tree rhs = gimple_assign_rhs1 (stmt); |
932 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR | |
933 | || (gimple_assign_rhs_code (stmt) == ADDR_EXPR | |
934 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == MEM_REF)) | |
726a989a | 935 | reexamine = plus_stmt_object_size (osi, var, stmt); |
4e71066d RG |
936 | else if (gimple_assign_rhs_code (stmt) == COND_EXPR) |
937 | reexamine = cond_expr_object_size (osi, var, stmt); | |
726a989a RB |
938 | else if (gimple_assign_single_p (stmt) |
939 | || gimple_assign_unary_nop_p (stmt)) | |
940 | { | |
726a989a RB |
941 | if (TREE_CODE (rhs) == SSA_NAME |
942 | && POINTER_TYPE_P (TREE_TYPE (rhs))) | |
943 | reexamine = merge_object_sizes (osi, var, rhs, 0); | |
726a989a RB |
944 | else |
945 | expr_object_size (osi, var, rhs); | |
946 | } | |
947 | else | |
948 | unknown_object_size (osi, var); | |
949 | break; | |
950 | } | |
f255541f | 951 | |
726a989a RB |
952 | case GIMPLE_CALL: |
953 | { | |
954 | tree arg = pass_through_call (stmt); | |
955 | if (arg) | |
956 | { | |
957 | if (TREE_CODE (arg) == SSA_NAME | |
958 | && POINTER_TYPE_P (TREE_TYPE (arg))) | |
959 | reexamine = merge_object_sizes (osi, var, arg, 0); | |
726a989a RB |
960 | else |
961 | expr_object_size (osi, var, arg); | |
962 | } | |
963 | else | |
964 | call_object_size (osi, var, stmt); | |
10a0d495 JJ |
965 | break; |
966 | } | |
967 | ||
726a989a | 968 | case GIMPLE_ASM: |
10a0d495 JJ |
969 | /* Pointers defined by __asm__ statements can point anywhere. */ |
970 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
971 | break; | |
972 | ||
726a989a | 973 | case GIMPLE_NOP: |
70b5e7dc RG |
974 | if (SSA_NAME_VAR (var) |
975 | && TREE_CODE (SSA_NAME_VAR (var)) == PARM_DECL) | |
976 | expr_object_size (osi, var, SSA_NAME_VAR (var)); | |
977 | else | |
978 | /* Uninitialized SSA names point nowhere. */ | |
979 | object_sizes[object_size_type][varno] = unknown[object_size_type]; | |
10a0d495 JJ |
980 | break; |
981 | ||
726a989a | 982 | case GIMPLE_PHI: |
10a0d495 | 983 | { |
726a989a | 984 | unsigned i; |
10a0d495 | 985 | |
726a989a | 986 | for (i = 0; i < gimple_phi_num_args (stmt); i++) |
10a0d495 | 987 | { |
726a989a | 988 | tree rhs = gimple_phi_arg (stmt, i)->def; |
10a0d495 JJ |
989 | |
990 | if (object_sizes[object_size_type][varno] | |
991 | == unknown[object_size_type]) | |
992 | break; | |
993 | ||
994 | if (TREE_CODE (rhs) == SSA_NAME) | |
995 | reexamine |= merge_object_sizes (osi, var, rhs, 0); | |
996 | else if (osi->pass == 0) | |
997 | expr_object_size (osi, var, rhs); | |
998 | } | |
999 | break; | |
1000 | } | |
726a989a | 1001 | |
10a0d495 JJ |
1002 | default: |
1003 | gcc_unreachable (); | |
1004 | } | |
1005 | ||
1006 | if (! reexamine | |
1007 | || object_sizes[object_size_type][varno] == unknown[object_size_type]) | |
1008 | { | |
1009 | bitmap_set_bit (computed[object_size_type], varno); | |
1010 | bitmap_clear_bit (osi->reexamine, varno); | |
1011 | } | |
1012 | else | |
1013 | { | |
1014 | bitmap_set_bit (osi->reexamine, varno); | |
1015 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1016 | { | |
1017 | fprintf (dump_file, "Need to reexamine "); | |
1018 | print_generic_expr (dump_file, var, dump_flags); | |
1019 | fprintf (dump_file, "\n"); | |
1020 | } | |
1021 | } | |
1022 | } | |
1023 | ||
1024 | ||
1025 | /* Helper function for check_for_plus_in_loops. Called recursively | |
1026 | to detect loops. */ | |
1027 | ||
1028 | static void | |
1029 | check_for_plus_in_loops_1 (struct object_size_info *osi, tree var, | |
1030 | unsigned int depth) | |
1031 | { | |
726a989a | 1032 | gimple stmt = SSA_NAME_DEF_STMT (var); |
10a0d495 JJ |
1033 | unsigned int varno = SSA_NAME_VERSION (var); |
1034 | ||
1035 | if (osi->depths[varno]) | |
1036 | { | |
1037 | if (osi->depths[varno] != depth) | |
1038 | { | |
1039 | unsigned int *sp; | |
1040 | ||
1041 | /* Found a loop involving pointer addition. */ | |
1042 | for (sp = osi->tos; sp > osi->stack; ) | |
1043 | { | |
1044 | --sp; | |
1045 | bitmap_clear_bit (osi->reexamine, *sp); | |
1046 | bitmap_set_bit (computed[osi->object_size_type], *sp); | |
1047 | object_sizes[osi->object_size_type][*sp] = 0; | |
1048 | if (*sp == varno) | |
1049 | break; | |
1050 | } | |
1051 | } | |
1052 | return; | |
1053 | } | |
1054 | else if (! bitmap_bit_p (osi->reexamine, varno)) | |
1055 | return; | |
1056 | ||
1057 | osi->depths[varno] = depth; | |
1058 | *osi->tos++ = varno; | |
1059 | ||
726a989a | 1060 | switch (gimple_code (stmt)) |
10a0d495 | 1061 | { |
10a0d495 | 1062 | |
726a989a | 1063 | case GIMPLE_ASSIGN: |
10a0d495 | 1064 | { |
726a989a RB |
1065 | if ((gimple_assign_single_p (stmt) |
1066 | || gimple_assign_unary_nop_p (stmt)) | |
1067 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
1068 | { | |
1069 | tree rhs = gimple_assign_rhs1 (stmt); | |
1070 | ||
1071 | check_for_plus_in_loops_1 (osi, rhs, depth); | |
1072 | } | |
1073 | else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) | |
1074 | { | |
1075 | tree basevar = gimple_assign_rhs1 (stmt); | |
1076 | tree cst = gimple_assign_rhs2 (stmt); | |
1077 | ||
1078 | gcc_assert (TREE_CODE (cst) == INTEGER_CST); | |
1079 | ||
1080 | check_for_plus_in_loops_1 (osi, basevar, | |
1081 | depth + !integer_zerop (cst)); | |
1082 | } | |
1083 | else | |
1084 | gcc_unreachable (); | |
1085 | break; | |
1086 | } | |
10a0d495 | 1087 | |
726a989a RB |
1088 | case GIMPLE_CALL: |
1089 | { | |
1090 | tree arg = pass_through_call (stmt); | |
1091 | if (arg) | |
1092 | { | |
1093 | if (TREE_CODE (arg) == SSA_NAME) | |
1094 | check_for_plus_in_loops_1 (osi, arg, depth); | |
1095 | else | |
1096 | gcc_unreachable (); | |
1097 | } | |
1098 | break; | |
10a0d495 | 1099 | } |
726a989a RB |
1100 | |
1101 | case GIMPLE_PHI: | |
10a0d495 | 1102 | { |
726a989a | 1103 | unsigned i; |
10a0d495 | 1104 | |
726a989a | 1105 | for (i = 0; i < gimple_phi_num_args (stmt); i++) |
10a0d495 | 1106 | { |
726a989a | 1107 | tree rhs = gimple_phi_arg (stmt, i)->def; |
10a0d495 JJ |
1108 | |
1109 | if (TREE_CODE (rhs) == SSA_NAME) | |
1110 | check_for_plus_in_loops_1 (osi, rhs, depth); | |
1111 | } | |
1112 | break; | |
1113 | } | |
726a989a | 1114 | |
10a0d495 JJ |
1115 | default: |
1116 | gcc_unreachable (); | |
1117 | } | |
1118 | ||
1119 | osi->depths[varno] = 0; | |
1120 | osi->tos--; | |
1121 | } | |
1122 | ||
1123 | ||
1124 | /* Check if some pointer we are computing object size of is being increased | |
1125 | within a loop. If yes, assume all the SSA variables participating in | |
1126 | that loop have minimum object sizes 0. */ | |
1127 | ||
1128 | static void | |
1129 | check_for_plus_in_loops (struct object_size_info *osi, tree var) | |
1130 | { | |
726a989a | 1131 | gimple stmt = SSA_NAME_DEF_STMT (var); |
10a0d495 | 1132 | |
726a989a RB |
1133 | /* NOTE: In the pre-tuples code, we handled a CALL_EXPR here, |
1134 | and looked for a POINTER_PLUS_EXPR in the pass-through | |
1135 | argument, if any. In GIMPLE, however, such an expression | |
1136 | is not a valid call operand. */ | |
10a0d495 | 1137 | |
726a989a RB |
1138 | if (is_gimple_assign (stmt) |
1139 | && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) | |
1140 | { | |
1141 | tree basevar = gimple_assign_rhs1 (stmt); | |
1142 | tree cst = gimple_assign_rhs2 (stmt); | |
b8698a0f | 1143 | |
726a989a RB |
1144 | gcc_assert (TREE_CODE (cst) == INTEGER_CST); |
1145 | ||
1146 | if (integer_zerop (cst)) | |
1147 | return; | |
1148 | ||
1149 | osi->depths[SSA_NAME_VERSION (basevar)] = 1; | |
1150 | *osi->tos++ = SSA_NAME_VERSION (basevar); | |
1151 | check_for_plus_in_loops_1 (osi, var, 2); | |
1152 | osi->depths[SSA_NAME_VERSION (basevar)] = 0; | |
1153 | osi->tos--; | |
10a0d495 JJ |
1154 | } |
1155 | } | |
1156 | ||
1157 | ||
1158 | /* Initialize data structures for the object size computation. */ | |
1159 | ||
1160 | void | |
1161 | init_object_sizes (void) | |
1162 | { | |
1163 | int object_size_type; | |
1164 | ||
1165 | if (object_sizes[0]) | |
1166 | return; | |
1167 | ||
1168 | for (object_size_type = 0; object_size_type <= 3; object_size_type++) | |
1169 | { | |
5ed6ace5 | 1170 | object_sizes[object_size_type] = XNEWVEC (unsigned HOST_WIDE_INT, num_ssa_names); |
10a0d495 JJ |
1171 | computed[object_size_type] = BITMAP_ALLOC (NULL); |
1172 | } | |
1173 | ||
1174 | init_offset_limit (); | |
1175 | } | |
1176 | ||
1177 | ||
1178 | /* Destroy data structures after the object size computation. */ | |
1179 | ||
1180 | void | |
1181 | fini_object_sizes (void) | |
1182 | { | |
1183 | int object_size_type; | |
1184 | ||
1185 | for (object_size_type = 0; object_size_type <= 3; object_size_type++) | |
1186 | { | |
1187 | free (object_sizes[object_size_type]); | |
1188 | BITMAP_FREE (computed[object_size_type]); | |
1189 | object_sizes[object_size_type] = NULL; | |
1190 | } | |
1191 | } | |
1192 | ||
1193 | ||
1194 | /* Simple pass to optimize all __builtin_object_size () builtins. */ | |
1195 | ||
c2924966 | 1196 | static unsigned int |
10a0d495 JJ |
1197 | compute_object_sizes (void) |
1198 | { | |
1199 | basic_block bb; | |
1200 | FOR_EACH_BB (bb) | |
1201 | { | |
726a989a RB |
1202 | gimple_stmt_iterator i; |
1203 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) | |
10a0d495 | 1204 | { |
10a0d495 | 1205 | tree callee, result; |
726a989a | 1206 | gimple call = gsi_stmt (i); |
10a0d495 | 1207 | |
726a989a | 1208 | if (gimple_code (call) != GIMPLE_CALL) |
10a0d495 JJ |
1209 | continue; |
1210 | ||
726a989a | 1211 | callee = gimple_call_fndecl (call); |
10a0d495 JJ |
1212 | if (!callee |
1213 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
1214 | || DECL_FUNCTION_CODE (callee) != BUILT_IN_OBJECT_SIZE) | |
1215 | continue; | |
1216 | ||
1217 | init_object_sizes (); | |
726a989a | 1218 | result = fold_call_stmt (call, false); |
10a0d495 JJ |
1219 | if (!result) |
1220 | { | |
726a989a RB |
1221 | if (gimple_call_num_args (call) == 2 |
1222 | && POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) | |
10a0d495 | 1223 | { |
726a989a | 1224 | tree ost = gimple_call_arg (call, 1); |
10a0d495 JJ |
1225 | |
1226 | if (host_integerp (ost, 1)) | |
1227 | { | |
1228 | unsigned HOST_WIDE_INT object_size_type | |
1229 | = tree_low_cst (ost, 1); | |
1230 | ||
1231 | if (object_size_type < 2) | |
1232 | result = fold_convert (size_type_node, | |
1233 | integer_minus_one_node); | |
1234 | else if (object_size_type < 4) | |
e8160c9a | 1235 | result = build_zero_cst (size_type_node); |
10a0d495 JJ |
1236 | } |
1237 | } | |
1238 | ||
1239 | if (!result) | |
1240 | continue; | |
1241 | } | |
1242 | ||
1243 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1244 | { | |
1245 | fprintf (dump_file, "Simplified\n "); | |
726a989a | 1246 | print_gimple_stmt (dump_file, call, 0, dump_flags); |
10a0d495 JJ |
1247 | } |
1248 | ||
726a989a | 1249 | if (!update_call_from_tree (&i, result)) |
dd2c9f74 | 1250 | gcc_unreachable (); |
726a989a | 1251 | |
10a0d495 JJ |
1252 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1253 | { | |
1254 | fprintf (dump_file, "to\n "); | |
862a84f5 | 1255 | print_gimple_stmt (dump_file, gsi_stmt (i), 0, dump_flags); |
10a0d495 JJ |
1256 | fprintf (dump_file, "\n"); |
1257 | } | |
1258 | } | |
1259 | } | |
1260 | ||
1261 | fini_object_sizes (); | |
c2924966 | 1262 | return 0; |
10a0d495 JJ |
1263 | } |
1264 | ||
27a4cd48 DM |
1265 | namespace { |
1266 | ||
1267 | const pass_data pass_data_object_sizes = | |
10a0d495 | 1268 | { |
27a4cd48 DM |
1269 | GIMPLE_PASS, /* type */ |
1270 | "objsz", /* name */ | |
1271 | OPTGROUP_NONE, /* optinfo_flags */ | |
1272 | false, /* has_gate */ | |
1273 | true, /* has_execute */ | |
1274 | TV_NONE, /* tv_id */ | |
1275 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1276 | 0, /* properties_provided */ | |
1277 | 0, /* properties_destroyed */ | |
1278 | 0, /* todo_flags_start */ | |
1279 | TODO_verify_ssa, /* todo_flags_finish */ | |
10a0d495 | 1280 | }; |
27a4cd48 DM |
1281 | |
1282 | class pass_object_sizes : public gimple_opt_pass | |
1283 | { | |
1284 | public: | |
1285 | pass_object_sizes(gcc::context *ctxt) | |
1286 | : gimple_opt_pass(pass_data_object_sizes, ctxt) | |
1287 | {} | |
1288 | ||
1289 | /* opt_pass methods: */ | |
1290 | opt_pass * clone () { return new pass_object_sizes (ctxt_); } | |
1291 | unsigned int execute () { return compute_object_sizes (); } | |
1292 | ||
1293 | }; // class pass_object_sizes | |
1294 | ||
1295 | } // anon namespace | |
1296 | ||
1297 | gimple_opt_pass * | |
1298 | make_pass_object_sizes (gcc::context *ctxt) | |
1299 | { | |
1300 | return new pass_object_sizes (ctxt); | |
1301 | } |