| 1 | /* Tree based points-to analysis |
| 2 | Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. |
| 3 | Contributed by Daniel Berlin <dberlin@dberlin.org> |
| 4 | |
| 5 | This file is part of GCC. |
| 6 | |
| 7 | GCC is free software; you can redistribute it and/or modify |
| 8 | under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | GCC is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with GCC; see the file COPYING3. If not see |
| 19 | <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #include "config.h" |
| 22 | #include "system.h" |
| 23 | #include "coretypes.h" |
| 24 | #include "tm.h" |
| 25 | #include "ggc.h" |
| 26 | #include "obstack.h" |
| 27 | #include "bitmap.h" |
| 28 | #include "flags.h" |
| 29 | #include "rtl.h" |
| 30 | #include "tm_p.h" |
| 31 | #include "hard-reg-set.h" |
| 32 | #include "basic-block.h" |
| 33 | #include "output.h" |
| 34 | #include "tree.h" |
| 35 | #include "c-common.h" |
| 36 | #include "tree-flow.h" |
| 37 | #include "tree-inline.h" |
| 38 | #include "varray.h" |
| 39 | #include "c-tree.h" |
| 40 | #include "diagnostic.h" |
| 41 | #include "toplev.h" |
| 42 | #include "gimple.h" |
| 43 | #include "hashtab.h" |
| 44 | #include "function.h" |
| 45 | #include "cgraph.h" |
| 46 | #include "tree-pass.h" |
| 47 | #include "timevar.h" |
| 48 | #include "alloc-pool.h" |
| 49 | #include "splay-tree.h" |
| 50 | #include "params.h" |
| 51 | #include "tree-ssa-structalias.h" |
| 52 | #include "cgraph.h" |
| 53 | #include "alias.h" |
| 54 | #include "pointer-set.h" |
| 55 | |
| 56 | /* The idea behind this analyzer is to generate set constraints from the |
| 57 | program, then solve the resulting constraints in order to generate the |
| 58 | points-to sets. |
| 59 | |
| 60 | Set constraints are a way of modeling program analysis problems that |
| 61 | involve sets. They consist of an inclusion constraint language, |
| 62 | describing the variables (each variable is a set) and operations that |
| 63 | are involved on the variables, and a set of rules that derive facts |
| 64 | from these operations. To solve a system of set constraints, you derive |
| 65 | all possible facts under the rules, which gives you the correct sets |
| 66 | as a consequence. |
| 67 | |
| 68 | See "Efficient Field-sensitive pointer analysis for C" by "David |
| 69 | J. Pearce and Paul H. J. Kelly and Chris Hankin, at |
| 70 | http://citeseer.ist.psu.edu/pearce04efficient.html |
| 71 | |
| 72 | Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines |
| 73 | of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at |
| 74 | http://citeseer.ist.psu.edu/heintze01ultrafast.html |
| 75 | |
| 76 | There are three types of real constraint expressions, DEREF, |
| 77 | ADDRESSOF, and SCALAR. Each constraint expression consists |
| 78 | of a constraint type, a variable, and an offset. |
| 79 | |
| 80 | SCALAR is a constraint expression type used to represent x, whether |
| 81 | it appears on the LHS or the RHS of a statement. |
| 82 | DEREF is a constraint expression type used to represent *x, whether |
| 83 | it appears on the LHS or the RHS of a statement. |
| 84 | ADDRESSOF is a constraint expression used to represent &x, whether |
| 85 | it appears on the LHS or the RHS of a statement. |
| 86 | |
| 87 | Each pointer variable in the program is assigned an integer id, and |
| 88 | each field of a structure variable is assigned an integer id as well. |
| 89 | |
| 90 | Structure variables are linked to their list of fields through a "next |
| 91 | field" in each variable that points to the next field in offset |
| 92 | order. |
| 93 | Each variable for a structure field has |
| 94 | |
| 95 | 1. "size", that tells the size in bits of that field. |
| 96 | 2. "fullsize, that tells the size in bits of the entire structure. |
| 97 | 3. "offset", that tells the offset in bits from the beginning of the |
| 98 | structure to this field. |
| 99 | |
| 100 | Thus, |
| 101 | struct f |
| 102 | { |
| 103 | int a; |
| 104 | int b; |
| 105 | } foo; |
| 106 | int *bar; |
| 107 | |
| 108 | looks like |
| 109 | |
| 110 | foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b |
| 111 | foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL |
| 112 | bar -> id 3, size 32, offset 0, fullsize 32, next NULL |
| 113 | |
| 114 | |
| 115 | In order to solve the system of set constraints, the following is |
| 116 | done: |
| 117 | |
| 118 | 1. Each constraint variable x has a solution set associated with it, |
| 119 | Sol(x). |
| 120 | |
| 121 | 2. Constraints are separated into direct, copy, and complex. |
| 122 | Direct constraints are ADDRESSOF constraints that require no extra |
| 123 | processing, such as P = &Q |
| 124 | Copy constraints are those of the form P = Q. |
| 125 | Complex constraints are all the constraints involving dereferences |
| 126 | and offsets (including offsetted copies). |
| 127 | |
| 128 | 3. All direct constraints of the form P = &Q are processed, such |
| 129 | that Q is added to Sol(P) |
| 130 | |
| 131 | 4. All complex constraints for a given constraint variable are stored in a |
| 132 | linked list attached to that variable's node. |
| 133 | |
| 134 | 5. A directed graph is built out of the copy constraints. Each |
| 135 | constraint variable is a node in the graph, and an edge from |
| 136 | Q to P is added for each copy constraint of the form P = Q |
| 137 | |
| 138 | 6. The graph is then walked, and solution sets are |
| 139 | propagated along the copy edges, such that an edge from Q to P |
| 140 | causes Sol(P) <- Sol(P) union Sol(Q). |
| 141 | |
| 142 | 7. As we visit each node, all complex constraints associated with |
| 143 | that node are processed by adding appropriate copy edges to the graph, or the |
| 144 | appropriate variables to the solution set. |
| 145 | |
| 146 | 8. The process of walking the graph is iterated until no solution |
| 147 | sets change. |
| 148 | |
| 149 | Prior to walking the graph in steps 6 and 7, We perform static |
| 150 | cycle elimination on the constraint graph, as well |
| 151 | as off-line variable substitution. |
| 152 | |
| 153 | TODO: Adding offsets to pointer-to-structures can be handled (IE not punted |
| 154 | on and turned into anything), but isn't. You can just see what offset |
| 155 | inside the pointed-to struct it's going to access. |
| 156 | |
| 157 | TODO: Constant bounded arrays can be handled as if they were structs of the |
| 158 | same number of elements. |
| 159 | |
| 160 | TODO: Modeling heap and incoming pointers becomes much better if we |
| 161 | add fields to them as we discover them, which we could do. |
| 162 | |
| 163 | TODO: We could handle unions, but to be honest, it's probably not |
| 164 | worth the pain or slowdown. */ |
| 165 | |
| 166 | static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map))) |
| 167 | htab_t heapvar_for_stmt; |
| 168 | |
| 169 | static bool use_field_sensitive = true; |
| 170 | static int in_ipa_mode = 0; |
| 171 | |
| 172 | /* Used for predecessor bitmaps. */ |
| 173 | static bitmap_obstack predbitmap_obstack; |
| 174 | |
| 175 | /* Used for points-to sets. */ |
| 176 | static bitmap_obstack pta_obstack; |
| 177 | |
| 178 | /* Used for oldsolution members of variables. */ |
| 179 | static bitmap_obstack oldpta_obstack; |
| 180 | |
| 181 | /* Used for per-solver-iteration bitmaps. */ |
| 182 | static bitmap_obstack iteration_obstack; |
| 183 | |
| 184 | static unsigned int create_variable_info_for (tree, const char *); |
| 185 | typedef struct constraint_graph *constraint_graph_t; |
| 186 | static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool); |
| 187 | |
| 188 | DEF_VEC_P(constraint_t); |
| 189 | DEF_VEC_ALLOC_P(constraint_t,heap); |
| 190 | |
| 191 | #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \ |
| 192 | if (a) \ |
| 193 | EXECUTE_IF_SET_IN_BITMAP (a, b, c, d) |
| 194 | |
| 195 | static struct constraint_stats |
| 196 | { |
| 197 | unsigned int total_vars; |
| 198 | unsigned int nonpointer_vars; |
| 199 | unsigned int unified_vars_static; |
| 200 | unsigned int unified_vars_dynamic; |
| 201 | unsigned int iterations; |
| 202 | unsigned int num_edges; |
| 203 | unsigned int num_implicit_edges; |
| 204 | unsigned int points_to_sets_created; |
| 205 | } stats; |
| 206 | |
| 207 | struct variable_info |
| 208 | { |
| 209 | /* ID of this variable */ |
| 210 | unsigned int id; |
| 211 | |
| 212 | /* True if this is a variable created by the constraint analysis, such as |
| 213 | heap variables and constraints we had to break up. */ |
| 214 | unsigned int is_artificial_var:1; |
| 215 | |
| 216 | /* True if this is a special variable whose solution set should not be |
| 217 | changed. */ |
| 218 | unsigned int is_special_var:1; |
| 219 | |
| 220 | /* True for variables whose size is not known or variable. */ |
| 221 | unsigned int is_unknown_size_var:1; |
| 222 | |
| 223 | /* True for (sub-)fields that represent a whole variable. */ |
| 224 | unsigned int is_full_var : 1; |
| 225 | |
| 226 | /* True if this is a heap variable. */ |
| 227 | unsigned int is_heap_var:1; |
| 228 | |
| 229 | /* True if we may not use TBAA to prune references to this |
| 230 | variable. This is used for C++ placement new. */ |
| 231 | unsigned int no_tbaa_pruning : 1; |
| 232 | |
| 233 | /* True if this field may contain pointers. */ |
| 234 | unsigned int may_have_pointers : 1; |
| 235 | |
| 236 | /* Variable id this was collapsed to due to type unsafety. Zero if |
| 237 | this variable was not collapsed. This should be unused completely |
| 238 | after build_succ_graph, or something is broken. */ |
| 239 | unsigned int collapsed_to; |
| 240 | |
| 241 | /* A link to the variable for the next field in this structure. */ |
| 242 | struct variable_info *next; |
| 243 | |
| 244 | /* Offset of this variable, in bits, from the base variable */ |
| 245 | unsigned HOST_WIDE_INT offset; |
| 246 | |
| 247 | /* Size of the variable, in bits. */ |
| 248 | unsigned HOST_WIDE_INT size; |
| 249 | |
| 250 | /* Full size of the base variable, in bits. */ |
| 251 | unsigned HOST_WIDE_INT fullsize; |
| 252 | |
| 253 | /* Name of this variable */ |
| 254 | const char *name; |
| 255 | |
| 256 | /* Tree that this variable is associated with. */ |
| 257 | tree decl; |
| 258 | |
| 259 | /* Points-to set for this variable. */ |
| 260 | bitmap solution; |
| 261 | |
| 262 | /* Old points-to set for this variable. */ |
| 263 | bitmap oldsolution; |
| 264 | }; |
| 265 | typedef struct variable_info *varinfo_t; |
| 266 | |
| 267 | static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT); |
| 268 | static varinfo_t lookup_vi_for_tree (tree); |
| 269 | |
| 270 | /* Pool of variable info structures. */ |
| 271 | static alloc_pool variable_info_pool; |
| 272 | |
| 273 | DEF_VEC_P(varinfo_t); |
| 274 | |
| 275 | DEF_VEC_ALLOC_P(varinfo_t, heap); |
| 276 | |
| 277 | /* Table of variable info structures for constraint variables. |
| 278 | Indexed directly by variable info id. */ |
| 279 | static VEC(varinfo_t,heap) *varmap; |
| 280 | |
| 281 | /* Return the varmap element N */ |
| 282 | |
| 283 | static inline varinfo_t |
| 284 | get_varinfo (unsigned int n) |
| 285 | { |
| 286 | return VEC_index (varinfo_t, varmap, n); |
| 287 | } |
| 288 | |
| 289 | /* Return the varmap element N, following the collapsed_to link. */ |
| 290 | |
| 291 | static inline varinfo_t |
| 292 | get_varinfo_fc (unsigned int n) |
| 293 | { |
| 294 | varinfo_t v = VEC_index (varinfo_t, varmap, n); |
| 295 | |
| 296 | if (v->collapsed_to != 0) |
| 297 | return get_varinfo (v->collapsed_to); |
| 298 | return v; |
| 299 | } |
| 300 | |
| 301 | /* Static IDs for the special variables. */ |
| 302 | enum { nothing_id = 0, anything_id = 1, readonly_id = 2, |
| 303 | escaped_id = 3, nonlocal_id = 4, callused_id = 5, |
| 304 | storedanything_id = 6, integer_id = 7 }; |
| 305 | |
| 306 | /* Variable that represents the unknown pointer. */ |
| 307 | static varinfo_t var_anything; |
| 308 | static tree anything_tree; |
| 309 | |
| 310 | /* Variable that represents the NULL pointer. */ |
| 311 | static varinfo_t var_nothing; |
| 312 | static tree nothing_tree; |
| 313 | |
| 314 | /* Variable that represents read only memory. */ |
| 315 | static varinfo_t var_readonly; |
| 316 | static tree readonly_tree; |
| 317 | |
| 318 | /* Variable that represents escaped memory. */ |
| 319 | static varinfo_t var_escaped; |
| 320 | static tree escaped_tree; |
| 321 | |
| 322 | /* Variable that represents nonlocal memory. */ |
| 323 | static varinfo_t var_nonlocal; |
| 324 | static tree nonlocal_tree; |
| 325 | |
| 326 | /* Variable that represents call-used memory. */ |
| 327 | static varinfo_t var_callused; |
| 328 | static tree callused_tree; |
| 329 | |
| 330 | /* Variable that represents variables that are stored to anything. */ |
| 331 | static varinfo_t var_storedanything; |
| 332 | static tree storedanything_tree; |
| 333 | |
| 334 | /* Variable that represents integers. This is used for when people do things |
| 335 | like &0->a.b. */ |
| 336 | static varinfo_t var_integer; |
| 337 | static tree integer_tree; |
| 338 | |
| 339 | /* Lookup a heap var for FROM, and return it if we find one. */ |
| 340 | |
| 341 | static tree |
| 342 | heapvar_lookup (tree from) |
| 343 | { |
| 344 | struct tree_map *h, in; |
| 345 | in.base.from = from; |
| 346 | |
| 347 | h = (struct tree_map *) htab_find_with_hash (heapvar_for_stmt, &in, |
| 348 | htab_hash_pointer (from)); |
| 349 | if (h) |
| 350 | return h->to; |
| 351 | return NULL_TREE; |
| 352 | } |
| 353 | |
| 354 | /* Insert a mapping FROM->TO in the heap var for statement |
| 355 | hashtable. */ |
| 356 | |
| 357 | static void |
| 358 | heapvar_insert (tree from, tree to) |
| 359 | { |
| 360 | struct tree_map *h; |
| 361 | void **loc; |
| 362 | |
| 363 | h = GGC_NEW (struct tree_map); |
| 364 | h->hash = htab_hash_pointer (from); |
| 365 | h->base.from = from; |
| 366 | h->to = to; |
| 367 | loc = htab_find_slot_with_hash (heapvar_for_stmt, h, h->hash, INSERT); |
| 368 | *(struct tree_map **) loc = h; |
| 369 | } |
| 370 | |
| 371 | /* Return a new variable info structure consisting for a variable |
| 372 | named NAME, and using constraint graph node NODE. */ |
| 373 | |
| 374 | static varinfo_t |
| 375 | new_var_info (tree t, unsigned int id, const char *name) |
| 376 | { |
| 377 | varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool); |
| 378 | tree var; |
| 379 | |
| 380 | ret->id = id; |
| 381 | ret->name = name; |
| 382 | ret->decl = t; |
| 383 | ret->is_artificial_var = false; |
| 384 | ret->is_heap_var = false; |
| 385 | ret->is_special_var = false; |
| 386 | ret->is_unknown_size_var = false; |
| 387 | ret->is_full_var = false; |
| 388 | ret->may_have_pointers = true; |
| 389 | var = t; |
| 390 | if (TREE_CODE (var) == SSA_NAME) |
| 391 | var = SSA_NAME_VAR (var); |
| 392 | ret->no_tbaa_pruning = (DECL_P (var) |
| 393 | && POINTER_TYPE_P (TREE_TYPE (var)) |
| 394 | && DECL_NO_TBAA_P (var)); |
| 395 | ret->solution = BITMAP_ALLOC (&pta_obstack); |
| 396 | ret->oldsolution = BITMAP_ALLOC (&oldpta_obstack); |
| 397 | ret->next = NULL; |
| 398 | ret->collapsed_to = 0; |
| 399 | return ret; |
| 400 | } |
| 401 | |
| 402 | typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type; |
| 403 | |
| 404 | /* An expression that appears in a constraint. */ |
| 405 | |
| 406 | struct constraint_expr |
| 407 | { |
| 408 | /* Constraint type. */ |
| 409 | constraint_expr_type type; |
| 410 | |
| 411 | /* Variable we are referring to in the constraint. */ |
| 412 | unsigned int var; |
| 413 | |
| 414 | /* Offset, in bits, of this constraint from the beginning of |
| 415 | variables it ends up referring to. |
| 416 | |
| 417 | IOW, in a deref constraint, we would deref, get the result set, |
| 418 | then add OFFSET to each member. */ |
| 419 | unsigned HOST_WIDE_INT offset; |
| 420 | }; |
| 421 | |
| 422 | typedef struct constraint_expr ce_s; |
| 423 | DEF_VEC_O(ce_s); |
| 424 | DEF_VEC_ALLOC_O(ce_s, heap); |
| 425 | static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool); |
| 426 | static void get_constraint_for (tree, VEC(ce_s, heap) **); |
| 427 | static void do_deref (VEC (ce_s, heap) **); |
| 428 | |
| 429 | /* Our set constraints are made up of two constraint expressions, one |
| 430 | LHS, and one RHS. |
| 431 | |
| 432 | As described in the introduction, our set constraints each represent an |
| 433 | operation between set valued variables. |
| 434 | */ |
| 435 | struct constraint |
| 436 | { |
| 437 | struct constraint_expr lhs; |
| 438 | struct constraint_expr rhs; |
| 439 | }; |
| 440 | |
| 441 | /* List of constraints that we use to build the constraint graph from. */ |
| 442 | |
| 443 | static VEC(constraint_t,heap) *constraints; |
| 444 | static alloc_pool constraint_pool; |
| 445 | |
| 446 | |
| 447 | DEF_VEC_I(int); |
| 448 | DEF_VEC_ALLOC_I(int, heap); |
| 449 | |
| 450 | /* The constraint graph is represented as an array of bitmaps |
| 451 | containing successor nodes. */ |
| 452 | |
| 453 | struct constraint_graph |
| 454 | { |
| 455 | /* Size of this graph, which may be different than the number of |
| 456 | nodes in the variable map. */ |
| 457 | unsigned int size; |
| 458 | |
| 459 | /* Explicit successors of each node. */ |
| 460 | bitmap *succs; |
| 461 | |
| 462 | /* Implicit predecessors of each node (Used for variable |
| 463 | substitution). */ |
| 464 | bitmap *implicit_preds; |
| 465 | |
| 466 | /* Explicit predecessors of each node (Used for variable substitution). */ |
| 467 | bitmap *preds; |
| 468 | |
| 469 | /* Indirect cycle representatives, or -1 if the node has no indirect |
| 470 | cycles. */ |
| 471 | int *indirect_cycles; |
| 472 | |
| 473 | /* Representative node for a node. rep[a] == a unless the node has |
| 474 | been unified. */ |
| 475 | unsigned int *rep; |
| 476 | |
| 477 | /* Equivalence class representative for a label. This is used for |
| 478 | variable substitution. */ |
| 479 | int *eq_rep; |
| 480 | |
| 481 | /* Pointer equivalence label for a node. All nodes with the same |
| 482 | pointer equivalence label can be unified together at some point |
| 483 | (either during constraint optimization or after the constraint |
| 484 | graph is built). */ |
| 485 | unsigned int *pe; |
| 486 | |
| 487 | /* Pointer equivalence representative for a label. This is used to |
| 488 | handle nodes that are pointer equivalent but not location |
| 489 | equivalent. We can unite these once the addressof constraints |
| 490 | are transformed into initial points-to sets. */ |
| 491 | int *pe_rep; |
| 492 | |
| 493 | /* Pointer equivalence label for each node, used during variable |
| 494 | substitution. */ |
| 495 | unsigned int *pointer_label; |
| 496 | |
| 497 | /* Location equivalence label for each node, used during location |
| 498 | equivalence finding. */ |
| 499 | unsigned int *loc_label; |
| 500 | |
| 501 | /* Pointed-by set for each node, used during location equivalence |
| 502 | finding. This is pointed-by rather than pointed-to, because it |
| 503 | is constructed using the predecessor graph. */ |
| 504 | bitmap *pointed_by; |
| 505 | |
| 506 | /* Points to sets for pointer equivalence. This is *not* the actual |
| 507 | points-to sets for nodes. */ |
| 508 | bitmap *points_to; |
| 509 | |
| 510 | /* Bitmap of nodes where the bit is set if the node is a direct |
| 511 | node. Used for variable substitution. */ |
| 512 | sbitmap direct_nodes; |
| 513 | |
| 514 | /* Bitmap of nodes where the bit is set if the node is address |
| 515 | taken. Used for variable substitution. */ |
| 516 | bitmap address_taken; |
| 517 | |
| 518 | /* Vector of complex constraints for each graph node. Complex |
| 519 | constraints are those involving dereferences or offsets that are |
| 520 | not 0. */ |
| 521 | VEC(constraint_t,heap) **complex; |
| 522 | }; |
| 523 | |
| 524 | static constraint_graph_t graph; |
| 525 | |
| 526 | /* During variable substitution and the offline version of indirect |
| 527 | cycle finding, we create nodes to represent dereferences and |
| 528 | address taken constraints. These represent where these start and |
| 529 | end. */ |
| 530 | #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap)) |
| 531 | #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1)) |
| 532 | |
| 533 | /* Return the representative node for NODE, if NODE has been unioned |
| 534 | with another NODE. |
| 535 | This function performs path compression along the way to finding |
| 536 | the representative. */ |
| 537 | |
| 538 | static unsigned int |
| 539 | find (unsigned int node) |
| 540 | { |
| 541 | gcc_assert (node < graph->size); |
| 542 | if (graph->rep[node] != node) |
| 543 | return graph->rep[node] = find (graph->rep[node]); |
| 544 | return node; |
| 545 | } |
| 546 | |
| 547 | /* Union the TO and FROM nodes to the TO nodes. |
| 548 | Note that at some point in the future, we may want to do |
| 549 | union-by-rank, in which case we are going to have to return the |
| 550 | node we unified to. */ |
| 551 | |
| 552 | static bool |
| 553 | unite (unsigned int to, unsigned int from) |
| 554 | { |
| 555 | gcc_assert (to < graph->size && from < graph->size); |
| 556 | if (to != from && graph->rep[from] != to) |
| 557 | { |
| 558 | graph->rep[from] = to; |
| 559 | return true; |
| 560 | } |
| 561 | return false; |
| 562 | } |
| 563 | |
| 564 | /* Create a new constraint consisting of LHS and RHS expressions. */ |
| 565 | |
| 566 | static constraint_t |
| 567 | new_constraint (const struct constraint_expr lhs, |
| 568 | const struct constraint_expr rhs) |
| 569 | { |
| 570 | constraint_t ret = (constraint_t) pool_alloc (constraint_pool); |
| 571 | ret->lhs = lhs; |
| 572 | ret->rhs = rhs; |
| 573 | return ret; |
| 574 | } |
| 575 | |
| 576 | /* Print out constraint C to FILE. */ |
| 577 | |
| 578 | void |
| 579 | dump_constraint (FILE *file, constraint_t c) |
| 580 | { |
| 581 | if (c->lhs.type == ADDRESSOF) |
| 582 | fprintf (file, "&"); |
| 583 | else if (c->lhs.type == DEREF) |
| 584 | fprintf (file, "*"); |
| 585 | fprintf (file, "%s", get_varinfo_fc (c->lhs.var)->name); |
| 586 | if (c->lhs.offset != 0) |
| 587 | fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset); |
| 588 | fprintf (file, " = "); |
| 589 | if (c->rhs.type == ADDRESSOF) |
| 590 | fprintf (file, "&"); |
| 591 | else if (c->rhs.type == DEREF) |
| 592 | fprintf (file, "*"); |
| 593 | fprintf (file, "%s", get_varinfo_fc (c->rhs.var)->name); |
| 594 | if (c->rhs.offset != 0) |
| 595 | fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset); |
| 596 | fprintf (file, "\n"); |
| 597 | } |
| 598 | |
| 599 | /* Print out constraint C to stderr. */ |
| 600 | |
| 601 | void |
| 602 | debug_constraint (constraint_t c) |
| 603 | { |
| 604 | dump_constraint (stderr, c); |
| 605 | } |
| 606 | |
| 607 | /* Print out all constraints to FILE */ |
| 608 | |
| 609 | void |
| 610 | dump_constraints (FILE *file) |
| 611 | { |
| 612 | int i; |
| 613 | constraint_t c; |
| 614 | for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++) |
| 615 | dump_constraint (file, c); |
| 616 | } |
| 617 | |
| 618 | /* Print out all constraints to stderr. */ |
| 619 | |
| 620 | void |
| 621 | debug_constraints (void) |
| 622 | { |
| 623 | dump_constraints (stderr); |
| 624 | } |
| 625 | |
| 626 | /* Print out to FILE the edge in the constraint graph that is created by |
| 627 | constraint c. The edge may have a label, depending on the type of |
| 628 | constraint that it represents. If complex1, e.g: a = *b, then the label |
| 629 | is "=*", if complex2, e.g: *a = b, then the label is "*=", if |
| 630 | complex with an offset, e.g: a = b + 8, then the label is "+". |
| 631 | Otherwise the edge has no label. */ |
| 632 | |
| 633 | void |
| 634 | dump_constraint_edge (FILE *file, constraint_t c) |
| 635 | { |
| 636 | if (c->rhs.type != ADDRESSOF) |
| 637 | { |
| 638 | const char *src = get_varinfo_fc (c->rhs.var)->name; |
| 639 | const char *dst = get_varinfo_fc (c->lhs.var)->name; |
| 640 | fprintf (file, " \"%s\" -> \"%s\" ", src, dst); |
| 641 | /* Due to preprocessing of constraints, instructions like *a = *b are |
| 642 | illegal; thus, we do not have to handle such cases. */ |
| 643 | if (c->lhs.type == DEREF) |
| 644 | fprintf (file, " [ label=\"*=\" ] ;\n"); |
| 645 | else if (c->rhs.type == DEREF) |
| 646 | fprintf (file, " [ label=\"=*\" ] ;\n"); |
| 647 | else |
| 648 | { |
| 649 | /* We must check the case where the constraint is an offset. |
| 650 | In this case, it is treated as a complex constraint. */ |
| 651 | if (c->rhs.offset != c->lhs.offset) |
| 652 | fprintf (file, " [ label=\"+\" ] ;\n"); |
| 653 | else |
| 654 | fprintf (file, " ;\n"); |
| 655 | } |
| 656 | } |
| 657 | } |
| 658 | |
| 659 | /* Print the constraint graph in dot format. */ |
| 660 | |
| 661 | void |
| 662 | dump_constraint_graph (FILE *file) |
| 663 | { |
| 664 | unsigned int i=0, size; |
| 665 | constraint_t c; |
| 666 | |
| 667 | /* Only print the graph if it has already been initialized: */ |
| 668 | if (!graph) |
| 669 | return; |
| 670 | |
| 671 | /* Print the constraints used to produce the constraint graph. The |
| 672 | constraints will be printed as comments in the dot file: */ |
| 673 | fprintf (file, "\n\n/* Constraints used in the constraint graph:\n"); |
| 674 | dump_constraints (file); |
| 675 | fprintf (file, "*/\n"); |
| 676 | |
| 677 | /* Prints the header of the dot file: */ |
| 678 | fprintf (file, "\n\n// The constraint graph in dot format:\n"); |
| 679 | fprintf (file, "strict digraph {\n"); |
| 680 | fprintf (file, " node [\n shape = box\n ]\n"); |
| 681 | fprintf (file, " edge [\n fontsize = \"12\"\n ]\n"); |
| 682 | fprintf (file, "\n // List of nodes in the constraint graph:\n"); |
| 683 | |
| 684 | /* The next lines print the nodes in the graph. In order to get the |
| 685 | number of nodes in the graph, we must choose the minimum between the |
| 686 | vector VEC (varinfo_t, varmap) and graph->size. If the graph has not |
| 687 | yet been initialized, then graph->size == 0, otherwise we must only |
| 688 | read nodes that have an entry in VEC (varinfo_t, varmap). */ |
| 689 | size = VEC_length (varinfo_t, varmap); |
| 690 | size = size < graph->size ? size : graph->size; |
| 691 | for (i = 0; i < size; i++) |
| 692 | { |
| 693 | const char *name = get_varinfo_fc (graph->rep[i])->name; |
| 694 | fprintf (file, " \"%s\" ;\n", name); |
| 695 | } |
| 696 | |
| 697 | /* Go over the list of constraints printing the edges in the constraint |
| 698 | graph. */ |
| 699 | fprintf (file, "\n // The constraint edges:\n"); |
| 700 | for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++) |
| 701 | if (c) |
| 702 | dump_constraint_edge (file, c); |
| 703 | |
| 704 | /* Prints the tail of the dot file. By now, only the closing bracket. */ |
| 705 | fprintf (file, "}\n\n\n"); |
| 706 | } |
| 707 | |
| 708 | /* Print out the constraint graph to stderr. */ |
| 709 | |
| 710 | void |
| 711 | debug_constraint_graph (void) |
| 712 | { |
| 713 | dump_constraint_graph (stderr); |
| 714 | } |
| 715 | |
| 716 | /* SOLVER FUNCTIONS |
| 717 | |
| 718 | The solver is a simple worklist solver, that works on the following |
| 719 | algorithm: |
| 720 | |
| 721 | sbitmap changed_nodes = all zeroes; |
| 722 | changed_count = 0; |
| 723 | For each node that is not already collapsed: |
| 724 | changed_count++; |
| 725 | set bit in changed nodes |
| 726 | |
| 727 | while (changed_count > 0) |
| 728 | { |
| 729 | compute topological ordering for constraint graph |
| 730 | |
| 731 | find and collapse cycles in the constraint graph (updating |
| 732 | changed if necessary) |
| 733 | |
| 734 | for each node (n) in the graph in topological order: |
| 735 | changed_count--; |
| 736 | |
| 737 | Process each complex constraint associated with the node, |
| 738 | updating changed if necessary. |
| 739 | |
| 740 | For each outgoing edge from n, propagate the solution from n to |
| 741 | the destination of the edge, updating changed as necessary. |
| 742 | |
| 743 | } */ |
| 744 | |
| 745 | /* Return true if two constraint expressions A and B are equal. */ |
| 746 | |
| 747 | static bool |
| 748 | constraint_expr_equal (struct constraint_expr a, struct constraint_expr b) |
| 749 | { |
| 750 | return a.type == b.type && a.var == b.var && a.offset == b.offset; |
| 751 | } |
| 752 | |
| 753 | /* Return true if constraint expression A is less than constraint expression |
| 754 | B. This is just arbitrary, but consistent, in order to give them an |
| 755 | ordering. */ |
| 756 | |
| 757 | static bool |
| 758 | constraint_expr_less (struct constraint_expr a, struct constraint_expr b) |
| 759 | { |
| 760 | if (a.type == b.type) |
| 761 | { |
| 762 | if (a.var == b.var) |
| 763 | return a.offset < b.offset; |
| 764 | else |
| 765 | return a.var < b.var; |
| 766 | } |
| 767 | else |
| 768 | return a.type < b.type; |
| 769 | } |
| 770 | |
| 771 | /* Return true if constraint A is less than constraint B. This is just |
| 772 | arbitrary, but consistent, in order to give them an ordering. */ |
| 773 | |
| 774 | static bool |
| 775 | constraint_less (const constraint_t a, const constraint_t b) |
| 776 | { |
| 777 | if (constraint_expr_less (a->lhs, b->lhs)) |
| 778 | return true; |
| 779 | else if (constraint_expr_less (b->lhs, a->lhs)) |
| 780 | return false; |
| 781 | else |
| 782 | return constraint_expr_less (a->rhs, b->rhs); |
| 783 | } |
| 784 | |
| 785 | /* Return true if two constraints A and B are equal. */ |
| 786 | |
| 787 | static bool |
| 788 | constraint_equal (struct constraint a, struct constraint b) |
| 789 | { |
| 790 | return constraint_expr_equal (a.lhs, b.lhs) |
| 791 | && constraint_expr_equal (a.rhs, b.rhs); |
| 792 | } |
| 793 | |
| 794 | |
| 795 | /* Find a constraint LOOKFOR in the sorted constraint vector VEC */ |
| 796 | |
| 797 | static constraint_t |
| 798 | constraint_vec_find (VEC(constraint_t,heap) *vec, |
| 799 | struct constraint lookfor) |
| 800 | { |
| 801 | unsigned int place; |
| 802 | constraint_t found; |
| 803 | |
| 804 | if (vec == NULL) |
| 805 | return NULL; |
| 806 | |
| 807 | place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less); |
| 808 | if (place >= VEC_length (constraint_t, vec)) |
| 809 | return NULL; |
| 810 | found = VEC_index (constraint_t, vec, place); |
| 811 | if (!constraint_equal (*found, lookfor)) |
| 812 | return NULL; |
| 813 | return found; |
| 814 | } |
| 815 | |
| 816 | /* Union two constraint vectors, TO and FROM. Put the result in TO. */ |
| 817 | |
| 818 | static void |
| 819 | constraint_set_union (VEC(constraint_t,heap) **to, |
| 820 | VEC(constraint_t,heap) **from) |
| 821 | { |
| 822 | int i; |
| 823 | constraint_t c; |
| 824 | |
| 825 | for (i = 0; VEC_iterate (constraint_t, *from, i, c); i++) |
| 826 | { |
| 827 | if (constraint_vec_find (*to, *c) == NULL) |
| 828 | { |
| 829 | unsigned int place = VEC_lower_bound (constraint_t, *to, c, |
| 830 | constraint_less); |
| 831 | VEC_safe_insert (constraint_t, heap, *to, place, c); |
| 832 | } |
| 833 | } |
| 834 | } |
| 835 | |
| 836 | /* Take a solution set SET, add OFFSET to each member of the set, and |
| 837 | overwrite SET with the result when done. */ |
| 838 | |
| 839 | static void |
| 840 | solution_set_add (bitmap set, unsigned HOST_WIDE_INT offset) |
| 841 | { |
| 842 | bitmap result = BITMAP_ALLOC (&iteration_obstack); |
| 843 | unsigned int i; |
| 844 | bitmap_iterator bi; |
| 845 | |
| 846 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) |
| 847 | { |
| 848 | varinfo_t vi = get_varinfo (i); |
| 849 | |
| 850 | /* If this is a variable with just one field just set its bit |
| 851 | in the result. */ |
| 852 | if (vi->is_artificial_var |
| 853 | || vi->is_unknown_size_var |
| 854 | || vi->is_full_var) |
| 855 | bitmap_set_bit (result, i); |
| 856 | else |
| 857 | { |
| 858 | unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset; |
| 859 | varinfo_t v = first_vi_for_offset (vi, fieldoffset); |
| 860 | /* If the result is outside of the variable use the last field. */ |
| 861 | if (!v) |
| 862 | { |
| 863 | v = vi; |
| 864 | while (v->next != NULL) |
| 865 | v = v->next; |
| 866 | } |
| 867 | bitmap_set_bit (result, v->id); |
| 868 | /* If the result is not exactly at fieldoffset include the next |
| 869 | field as well. See get_constraint_for_ptr_offset for more |
| 870 | rationale. */ |
| 871 | if (v->offset != fieldoffset |
| 872 | && v->next != NULL) |
| 873 | bitmap_set_bit (result, v->next->id); |
| 874 | } |
| 875 | } |
| 876 | |
| 877 | bitmap_copy (set, result); |
| 878 | BITMAP_FREE (result); |
| 879 | } |
| 880 | |
| 881 | /* Union solution sets TO and FROM, and add INC to each member of FROM in the |
| 882 | process. */ |
| 883 | |
| 884 | static bool |
| 885 | set_union_with_increment (bitmap to, bitmap from, unsigned HOST_WIDE_INT inc) |
| 886 | { |
| 887 | if (inc == 0) |
| 888 | return bitmap_ior_into (to, from); |
| 889 | else |
| 890 | { |
| 891 | bitmap tmp; |
| 892 | bool res; |
| 893 | |
| 894 | tmp = BITMAP_ALLOC (&iteration_obstack); |
| 895 | bitmap_copy (tmp, from); |
| 896 | solution_set_add (tmp, inc); |
| 897 | res = bitmap_ior_into (to, tmp); |
| 898 | BITMAP_FREE (tmp); |
| 899 | return res; |
| 900 | } |
| 901 | } |
| 902 | |
| 903 | /* Insert constraint C into the list of complex constraints for graph |
| 904 | node VAR. */ |
| 905 | |
| 906 | static void |
| 907 | insert_into_complex (constraint_graph_t graph, |
| 908 | unsigned int var, constraint_t c) |
| 909 | { |
| 910 | VEC (constraint_t, heap) *complex = graph->complex[var]; |
| 911 | unsigned int place = VEC_lower_bound (constraint_t, complex, c, |
| 912 | constraint_less); |
| 913 | |
| 914 | /* Only insert constraints that do not already exist. */ |
| 915 | if (place >= VEC_length (constraint_t, complex) |
| 916 | || !constraint_equal (*c, *VEC_index (constraint_t, complex, place))) |
| 917 | VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c); |
| 918 | } |
| 919 | |
| 920 | |
| 921 | /* Condense two variable nodes into a single variable node, by moving |
| 922 | all associated info from SRC to TO. */ |
| 923 | |
| 924 | static void |
| 925 | merge_node_constraints (constraint_graph_t graph, unsigned int to, |
| 926 | unsigned int from) |
| 927 | { |
| 928 | unsigned int i; |
| 929 | constraint_t c; |
| 930 | |
| 931 | gcc_assert (find (from) == to); |
| 932 | |
| 933 | /* Move all complex constraints from src node into to node */ |
| 934 | for (i = 0; VEC_iterate (constraint_t, graph->complex[from], i, c); i++) |
| 935 | { |
| 936 | /* In complex constraints for node src, we may have either |
| 937 | a = *src, and *src = a, or an offseted constraint which are |
| 938 | always added to the rhs node's constraints. */ |
| 939 | |
| 940 | if (c->rhs.type == DEREF) |
| 941 | c->rhs.var = to; |
| 942 | else if (c->lhs.type == DEREF) |
| 943 | c->lhs.var = to; |
| 944 | else |
| 945 | c->rhs.var = to; |
| 946 | } |
| 947 | constraint_set_union (&graph->complex[to], &graph->complex[from]); |
| 948 | VEC_free (constraint_t, heap, graph->complex[from]); |
| 949 | graph->complex[from] = NULL; |
| 950 | } |
| 951 | |
| 952 | |
| 953 | /* Remove edges involving NODE from GRAPH. */ |
| 954 | |
| 955 | static void |
| 956 | clear_edges_for_node (constraint_graph_t graph, unsigned int node) |
| 957 | { |
| 958 | if (graph->succs[node]) |
| 959 | BITMAP_FREE (graph->succs[node]); |
| 960 | } |
| 961 | |
| 962 | /* Merge GRAPH nodes FROM and TO into node TO. */ |
| 963 | |
| 964 | static void |
| 965 | merge_graph_nodes (constraint_graph_t graph, unsigned int to, |
| 966 | unsigned int from) |
| 967 | { |
| 968 | if (graph->indirect_cycles[from] != -1) |
| 969 | { |
| 970 | /* If we have indirect cycles with the from node, and we have |
| 971 | none on the to node, the to node has indirect cycles from the |
| 972 | from node now that they are unified. |
| 973 | If indirect cycles exist on both, unify the nodes that they |
| 974 | are in a cycle with, since we know they are in a cycle with |
| 975 | each other. */ |
| 976 | if (graph->indirect_cycles[to] == -1) |
| 977 | graph->indirect_cycles[to] = graph->indirect_cycles[from]; |
| 978 | } |
| 979 | |
| 980 | /* Merge all the successor edges. */ |
| 981 | if (graph->succs[from]) |
| 982 | { |
| 983 | if (!graph->succs[to]) |
| 984 | graph->succs[to] = BITMAP_ALLOC (&pta_obstack); |
| 985 | bitmap_ior_into (graph->succs[to], |
| 986 | graph->succs[from]); |
| 987 | } |
| 988 | |
| 989 | clear_edges_for_node (graph, from); |
| 990 | } |
| 991 | |
| 992 | |
| 993 | /* Add an indirect graph edge to GRAPH, going from TO to FROM if |
| 994 | it doesn't exist in the graph already. */ |
| 995 | |
| 996 | static void |
| 997 | add_implicit_graph_edge (constraint_graph_t graph, unsigned int to, |
| 998 | unsigned int from) |
| 999 | { |
| 1000 | if (to == from) |
| 1001 | return; |
| 1002 | |
| 1003 | if (!graph->implicit_preds[to]) |
| 1004 | graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack); |
| 1005 | |
| 1006 | if (bitmap_set_bit (graph->implicit_preds[to], from)) |
| 1007 | stats.num_implicit_edges++; |
| 1008 | } |
| 1009 | |
| 1010 | /* Add a predecessor graph edge to GRAPH, going from TO to FROM if |
| 1011 | it doesn't exist in the graph already. |
| 1012 | Return false if the edge already existed, true otherwise. */ |
| 1013 | |
| 1014 | static void |
| 1015 | add_pred_graph_edge (constraint_graph_t graph, unsigned int to, |
| 1016 | unsigned int from) |
| 1017 | { |
| 1018 | if (!graph->preds[to]) |
| 1019 | graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack); |
| 1020 | bitmap_set_bit (graph->preds[to], from); |
| 1021 | } |
| 1022 | |
| 1023 | /* Add a graph edge to GRAPH, going from FROM to TO if |
| 1024 | it doesn't exist in the graph already. |
| 1025 | Return false if the edge already existed, true otherwise. */ |
| 1026 | |
| 1027 | static bool |
| 1028 | add_graph_edge (constraint_graph_t graph, unsigned int to, |
| 1029 | unsigned int from) |
| 1030 | { |
| 1031 | if (to == from) |
| 1032 | { |
| 1033 | return false; |
| 1034 | } |
| 1035 | else |
| 1036 | { |
| 1037 | bool r = false; |
| 1038 | |
| 1039 | if (!graph->succs[from]) |
| 1040 | graph->succs[from] = BITMAP_ALLOC (&pta_obstack); |
| 1041 | if (bitmap_set_bit (graph->succs[from], to)) |
| 1042 | { |
| 1043 | r = true; |
| 1044 | if (to < FIRST_REF_NODE && from < FIRST_REF_NODE) |
| 1045 | stats.num_edges++; |
| 1046 | } |
| 1047 | return r; |
| 1048 | } |
| 1049 | } |
| 1050 | |
| 1051 | |
| 1052 | /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */ |
| 1053 | |
| 1054 | static bool |
| 1055 | valid_graph_edge (constraint_graph_t graph, unsigned int src, |
| 1056 | unsigned int dest) |
| 1057 | { |
| 1058 | return (graph->succs[dest] |
| 1059 | && bitmap_bit_p (graph->succs[dest], src)); |
| 1060 | } |
| 1061 | |
| 1062 | /* Initialize the constraint graph structure to contain SIZE nodes. */ |
| 1063 | |
| 1064 | static void |
| 1065 | init_graph (unsigned int size) |
| 1066 | { |
| 1067 | unsigned int j; |
| 1068 | |
| 1069 | graph = XCNEW (struct constraint_graph); |
| 1070 | graph->size = size; |
| 1071 | graph->succs = XCNEWVEC (bitmap, graph->size); |
| 1072 | graph->indirect_cycles = XNEWVEC (int, graph->size); |
| 1073 | graph->rep = XNEWVEC (unsigned int, graph->size); |
| 1074 | graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size); |
| 1075 | graph->pe = XCNEWVEC (unsigned int, graph->size); |
| 1076 | graph->pe_rep = XNEWVEC (int, graph->size); |
| 1077 | |
| 1078 | for (j = 0; j < graph->size; j++) |
| 1079 | { |
| 1080 | graph->rep[j] = j; |
| 1081 | graph->pe_rep[j] = -1; |
| 1082 | graph->indirect_cycles[j] = -1; |
| 1083 | } |
| 1084 | } |
| 1085 | |
| 1086 | /* Build the constraint graph, adding only predecessor edges right now. */ |
| 1087 | |
| 1088 | static void |
| 1089 | build_pred_graph (void) |
| 1090 | { |
| 1091 | int i; |
| 1092 | constraint_t c; |
| 1093 | unsigned int j; |
| 1094 | |
| 1095 | graph->implicit_preds = XCNEWVEC (bitmap, graph->size); |
| 1096 | graph->preds = XCNEWVEC (bitmap, graph->size); |
| 1097 | graph->pointer_label = XCNEWVEC (unsigned int, graph->size); |
| 1098 | graph->loc_label = XCNEWVEC (unsigned int, graph->size); |
| 1099 | graph->pointed_by = XCNEWVEC (bitmap, graph->size); |
| 1100 | graph->points_to = XCNEWVEC (bitmap, graph->size); |
| 1101 | graph->eq_rep = XNEWVEC (int, graph->size); |
| 1102 | graph->direct_nodes = sbitmap_alloc (graph->size); |
| 1103 | graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack); |
| 1104 | sbitmap_zero (graph->direct_nodes); |
| 1105 | |
| 1106 | for (j = 0; j < FIRST_REF_NODE; j++) |
| 1107 | { |
| 1108 | if (!get_varinfo (j)->is_special_var) |
| 1109 | SET_BIT (graph->direct_nodes, j); |
| 1110 | } |
| 1111 | |
| 1112 | for (j = 0; j < graph->size; j++) |
| 1113 | graph->eq_rep[j] = -1; |
| 1114 | |
| 1115 | for (j = 0; j < VEC_length (varinfo_t, varmap); j++) |
| 1116 | graph->indirect_cycles[j] = -1; |
| 1117 | |
| 1118 | for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++) |
| 1119 | { |
| 1120 | struct constraint_expr lhs = c->lhs; |
| 1121 | struct constraint_expr rhs = c->rhs; |
| 1122 | unsigned int lhsvar = get_varinfo_fc (lhs.var)->id; |
| 1123 | unsigned int rhsvar = get_varinfo_fc (rhs.var)->id; |
| 1124 | |
| 1125 | if (lhs.type == DEREF) |
| 1126 | { |
| 1127 | /* *x = y. */ |
| 1128 | if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR) |
| 1129 | add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar); |
| 1130 | } |
| 1131 | else if (rhs.type == DEREF) |
| 1132 | { |
| 1133 | /* x = *y */ |
| 1134 | if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR) |
| 1135 | add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar); |
| 1136 | else |
| 1137 | RESET_BIT (graph->direct_nodes, lhsvar); |
| 1138 | } |
| 1139 | else if (rhs.type == ADDRESSOF) |
| 1140 | { |
| 1141 | varinfo_t v; |
| 1142 | |
| 1143 | /* x = &y */ |
| 1144 | if (graph->points_to[lhsvar] == NULL) |
| 1145 | graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack); |
| 1146 | bitmap_set_bit (graph->points_to[lhsvar], rhsvar); |
| 1147 | |
| 1148 | if (graph->pointed_by[rhsvar] == NULL) |
| 1149 | graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack); |
| 1150 | bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar); |
| 1151 | |
| 1152 | /* Implicitly, *x = y */ |
| 1153 | add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar); |
| 1154 | |
| 1155 | /* All related variables are no longer direct nodes. */ |
| 1156 | RESET_BIT (graph->direct_nodes, rhsvar); |
| 1157 | v = get_varinfo (rhsvar); |
| 1158 | if (!v->is_full_var) |
| 1159 | { |
| 1160 | v = lookup_vi_for_tree (v->decl); |
| 1161 | do |
| 1162 | { |
| 1163 | RESET_BIT (graph->direct_nodes, v->id); |
| 1164 | v = v->next; |
| 1165 | } |
| 1166 | while (v != NULL); |
| 1167 | } |
| 1168 | bitmap_set_bit (graph->address_taken, rhsvar); |
| 1169 | } |
| 1170 | else if (lhsvar > anything_id |
| 1171 | && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0) |
| 1172 | { |
| 1173 | /* x = y */ |
| 1174 | add_pred_graph_edge (graph, lhsvar, rhsvar); |
| 1175 | /* Implicitly, *x = *y */ |
| 1176 | add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, |
| 1177 | FIRST_REF_NODE + rhsvar); |
| 1178 | } |
| 1179 | else if (lhs.offset != 0 || rhs.offset != 0) |
| 1180 | { |
| 1181 | if (rhs.offset != 0) |
| 1182 | RESET_BIT (graph->direct_nodes, lhs.var); |
| 1183 | else if (lhs.offset != 0) |
| 1184 | RESET_BIT (graph->direct_nodes, rhs.var); |
| 1185 | } |
| 1186 | } |
| 1187 | } |
| 1188 | |
| 1189 | /* Build the constraint graph, adding successor edges. */ |
| 1190 | |
| 1191 | static void |
| 1192 | build_succ_graph (void) |
| 1193 | { |
| 1194 | unsigned i, t; |
| 1195 | constraint_t c; |
| 1196 | |
| 1197 | for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++) |
| 1198 | { |
| 1199 | struct constraint_expr lhs; |
| 1200 | struct constraint_expr rhs; |
| 1201 | unsigned int lhsvar; |
| 1202 | unsigned int rhsvar; |
| 1203 | |
| 1204 | if (!c) |
| 1205 | continue; |
| 1206 | |
| 1207 | lhs = c->lhs; |
| 1208 | rhs = c->rhs; |
| 1209 | lhsvar = find (get_varinfo_fc (lhs.var)->id); |
| 1210 | rhsvar = find (get_varinfo_fc (rhs.var)->id); |
| 1211 | |
| 1212 | if (lhs.type == DEREF) |
| 1213 | { |
| 1214 | if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR) |
| 1215 | add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar); |
| 1216 | } |
| 1217 | else if (rhs.type == DEREF) |
| 1218 | { |
| 1219 | if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR) |
| 1220 | add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar); |
| 1221 | } |
| 1222 | else if (rhs.type == ADDRESSOF) |
| 1223 | { |
| 1224 | /* x = &y */ |
| 1225 | gcc_assert (find (get_varinfo_fc (rhs.var)->id) |
| 1226 | == get_varinfo_fc (rhs.var)->id); |
| 1227 | bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar); |
| 1228 | } |
| 1229 | else if (lhsvar > anything_id |
| 1230 | && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0) |
| 1231 | { |
| 1232 | add_graph_edge (graph, lhsvar, rhsvar); |
| 1233 | } |
| 1234 | } |
| 1235 | |
| 1236 | /* Add edges from STOREDANYTHING to all non-direct nodes. */ |
| 1237 | t = find (storedanything_id); |
| 1238 | for (i = integer_id + 1; i < FIRST_REF_NODE; ++i) |
| 1239 | { |
| 1240 | if (!TEST_BIT (graph->direct_nodes, i)) |
| 1241 | add_graph_edge (graph, find (i), t); |
| 1242 | } |
| 1243 | } |
| 1244 | |
| 1245 | |
| 1246 | /* Changed variables on the last iteration. */ |
| 1247 | static unsigned int changed_count; |
| 1248 | static sbitmap changed; |
| 1249 | |
| 1250 | DEF_VEC_I(unsigned); |
| 1251 | DEF_VEC_ALLOC_I(unsigned,heap); |
| 1252 | |
| 1253 | |
| 1254 | /* Strongly Connected Component visitation info. */ |
| 1255 | |
| 1256 | struct scc_info |
| 1257 | { |
| 1258 | sbitmap visited; |
| 1259 | sbitmap deleted; |
| 1260 | unsigned int *dfs; |
| 1261 | unsigned int *node_mapping; |
| 1262 | int current_index; |
| 1263 | VEC(unsigned,heap) *scc_stack; |
| 1264 | }; |
| 1265 | |
| 1266 | |
| 1267 | /* Recursive routine to find strongly connected components in GRAPH. |
| 1268 | SI is the SCC info to store the information in, and N is the id of current |
| 1269 | graph node we are processing. |
| 1270 | |
| 1271 | This is Tarjan's strongly connected component finding algorithm, as |
| 1272 | modified by Nuutila to keep only non-root nodes on the stack. |
| 1273 | The algorithm can be found in "On finding the strongly connected |
| 1274 | connected components in a directed graph" by Esko Nuutila and Eljas |
| 1275 | Soisalon-Soininen, in Information Processing Letters volume 49, |
| 1276 | number 1, pages 9-14. */ |
| 1277 | |
| 1278 | static void |
| 1279 | scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n) |
| 1280 | { |
| 1281 | unsigned int i; |
| 1282 | bitmap_iterator bi; |
| 1283 | unsigned int my_dfs; |
| 1284 | |
| 1285 | SET_BIT (si->visited, n); |
| 1286 | si->dfs[n] = si->current_index ++; |
| 1287 | my_dfs = si->dfs[n]; |
| 1288 | |
| 1289 | /* Visit all the successors. */ |
| 1290 | EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi) |
| 1291 | { |
| 1292 | unsigned int w; |
| 1293 | |
| 1294 | if (i > LAST_REF_NODE) |
| 1295 | break; |
| 1296 | |
| 1297 | w = find (i); |
| 1298 | if (TEST_BIT (si->deleted, w)) |
| 1299 | continue; |
| 1300 | |
| 1301 | if (!TEST_BIT (si->visited, w)) |
| 1302 | scc_visit (graph, si, w); |
| 1303 | { |
| 1304 | unsigned int t = find (w); |
| 1305 | unsigned int nnode = find (n); |
| 1306 | gcc_assert (nnode == n); |
| 1307 | |
| 1308 | if (si->dfs[t] < si->dfs[nnode]) |
| 1309 | si->dfs[n] = si->dfs[t]; |
| 1310 | } |
| 1311 | } |
| 1312 | |
| 1313 | /* See if any components have been identified. */ |
| 1314 | if (si->dfs[n] == my_dfs) |
| 1315 | { |
| 1316 | if (VEC_length (unsigned, si->scc_stack) > 0 |
| 1317 | && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs) |
| 1318 | { |
| 1319 | bitmap scc = BITMAP_ALLOC (NULL); |
| 1320 | bool have_ref_node = n >= FIRST_REF_NODE; |
| 1321 | unsigned int lowest_node; |
| 1322 | bitmap_iterator bi; |
| 1323 | |
| 1324 | bitmap_set_bit (scc, n); |
| 1325 | |
| 1326 | while (VEC_length (unsigned, si->scc_stack) != 0 |
| 1327 | && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs) |
| 1328 | { |
| 1329 | unsigned int w = VEC_pop (unsigned, si->scc_stack); |
| 1330 | |
| 1331 | bitmap_set_bit (scc, w); |
| 1332 | if (w >= FIRST_REF_NODE) |
| 1333 | have_ref_node = true; |
| 1334 | } |
| 1335 | |
| 1336 | lowest_node = bitmap_first_set_bit (scc); |
| 1337 | gcc_assert (lowest_node < FIRST_REF_NODE); |
| 1338 | |
| 1339 | /* Collapse the SCC nodes into a single node, and mark the |
| 1340 | indirect cycles. */ |
| 1341 | EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi) |
| 1342 | { |
| 1343 | if (i < FIRST_REF_NODE) |
| 1344 | { |
| 1345 | if (unite (lowest_node, i)) |
| 1346 | unify_nodes (graph, lowest_node, i, false); |
| 1347 | } |
| 1348 | else |
| 1349 | { |
| 1350 | unite (lowest_node, i); |
| 1351 | graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node; |
| 1352 | } |
| 1353 | } |
| 1354 | } |
| 1355 | SET_BIT (si->deleted, n); |
| 1356 | } |
| 1357 | else |
| 1358 | VEC_safe_push (unsigned, heap, si->scc_stack, n); |
| 1359 | } |
| 1360 | |
| 1361 | /* Unify node FROM into node TO, updating the changed count if |
| 1362 | necessary when UPDATE_CHANGED is true. */ |
| 1363 | |
| 1364 | static void |
| 1365 | unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from, |
| 1366 | bool update_changed) |
| 1367 | { |
| 1368 | |
| 1369 | gcc_assert (to != from && find (to) == to); |
| 1370 | if (dump_file && (dump_flags & TDF_DETAILS)) |
| 1371 | fprintf (dump_file, "Unifying %s to %s\n", |
| 1372 | get_varinfo (from)->name, |
| 1373 | get_varinfo (to)->name); |
| 1374 | |
| 1375 | if (update_changed) |
| 1376 | stats.unified_vars_dynamic++; |
| 1377 | else |
| 1378 | stats.unified_vars_static++; |
| 1379 | |
| 1380 | merge_graph_nodes (graph, to, from); |
| 1381 | merge_node_constraints (graph, to, from); |
| 1382 | |
| 1383 | if (get_varinfo (from)->no_tbaa_pruning) |
| 1384 | get_varinfo (to)->no_tbaa_pruning = true; |
| 1385 | |
| 1386 | /* Mark TO as changed if FROM was changed. If TO was already marked |
| 1387 | as changed, decrease the changed count. */ |
| 1388 | |
| 1389 | if (update_changed && TEST_BIT (changed, from)) |
| 1390 | { |
| 1391 | RESET_BIT (changed, from); |
| 1392 | if (!TEST_BIT (changed, to)) |
| 1393 | SET_BIT (changed, to); |
| 1394 | else |
| 1395 | { |
| 1396 | gcc_assert (changed_count > 0); |
| 1397 | changed_count--; |
| 1398 | } |
| 1399 | } |
| 1400 | if (get_varinfo (from)->solution) |
| 1401 | { |
| 1402 | /* If the solution changes because of the merging, we need to mark |
| 1403 | the variable as changed. */ |
| 1404 | if (bitmap_ior_into (get_varinfo (to)->solution, |
| 1405 | get_varinfo (from)->solution)) |
| 1406 | { |
| 1407 | if (update_changed && !TEST_BIT (changed, to)) |
| 1408 | { |
| 1409 | SET_BIT (changed, to); |
| 1410 | changed_count++; |
| 1411 | } |
| 1412 | } |
| 1413 | |
| 1414 | BITMAP_FREE (get_varinfo (from)->solution); |
| 1415 | BITMAP_FREE (get_varinfo (from)->oldsolution); |
| 1416 | |
| 1417 | if (stats.iterations > 0) |
| 1418 | { |
| 1419 | BITMAP_FREE (get_varinfo (to)->oldsolution); |
| 1420 | get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack); |
| 1421 | } |
| 1422 | } |
| 1423 | if (valid_graph_edge (graph, to, to)) |
| 1424 | { |
| 1425 | if (graph->succs[to]) |
| 1426 | bitmap_clear_bit (graph->succs[to], to); |
| 1427 | } |
| 1428 | } |
| 1429 | |
| 1430 | /* Information needed to compute the topological ordering of a graph. */ |
| 1431 | |
| 1432 | struct topo_info |
| 1433 | { |
| 1434 | /* sbitmap of visited nodes. */ |
| 1435 | sbitmap visited; |
| 1436 | /* Array that stores the topological order of the graph, *in |
| 1437 | reverse*. */ |
| 1438 | VEC(unsigned,heap) *topo_order; |
| 1439 | }; |
| 1440 | |
| 1441 | |
| 1442 | /* Initialize and return a topological info structure. */ |
| 1443 | |
| 1444 | static struct topo_info * |
| 1445 | init_topo_info (void) |
| 1446 | { |
| 1447 | size_t size = graph->size; |
| 1448 | struct topo_info *ti = XNEW (struct topo_info); |
| 1449 | ti->visited = sbitmap_alloc (size); |
| 1450 | sbitmap_zero (ti->visited); |
| 1451 | ti->topo_order = VEC_alloc (unsigned, heap, 1); |
| 1452 | return ti; |
| 1453 | } |
| 1454 | |
| 1455 | |
| 1456 | /* Free the topological sort info pointed to by TI. */ |
| 1457 | |
| 1458 | static void |
| 1459 | free_topo_info (struct topo_info *ti) |
| 1460 | { |
| 1461 | sbitmap_free (ti->visited); |
| 1462 | VEC_free (unsigned, heap, ti->topo_order); |
| 1463 | free (ti); |
| 1464 | } |
| 1465 | |
| 1466 | /* Visit the graph in topological order, and store the order in the |
| 1467 | topo_info structure. */ |
| 1468 | |
| 1469 | static void |
| 1470 | topo_visit (constraint_graph_t graph, struct topo_info *ti, |
| 1471 | unsigned int n) |
| 1472 | { |
| 1473 | bitmap_iterator bi; |
| 1474 | unsigned int j; |
| 1475 | |
| 1476 | SET_BIT (ti->visited, n); |
| 1477 | |
| 1478 | if (graph->succs[n]) |
| 1479 | EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi) |
| 1480 | { |
| 1481 | if (!TEST_BIT (ti->visited, j)) |
| 1482 | topo_visit (graph, ti, j); |
| 1483 | } |
| 1484 | |
| 1485 | VEC_safe_push (unsigned, heap, ti->topo_order, n); |
| 1486 | } |
| 1487 | |
| 1488 | /* Return true if variable N + OFFSET is a legal field of N. */ |
| 1489 | |
| 1490 | static bool |
| 1491 | type_safe (unsigned int n, unsigned HOST_WIDE_INT *offset) |
| 1492 | { |
| 1493 | varinfo_t ninfo = get_varinfo (n); |
| 1494 | |
| 1495 | /* For things we've globbed to single variables, any offset into the |
| 1496 | variable acts like the entire variable, so that it becomes offset |
| 1497 | 0. */ |
| 1498 | if (ninfo->is_special_var |
| 1499 | || ninfo->is_artificial_var |
| 1500 | || ninfo->is_unknown_size_var |
| 1501 | || ninfo->is_full_var) |
| 1502 | { |
| 1503 | *offset = 0; |
| 1504 | return true; |
| 1505 | } |
| 1506 | return (get_varinfo (n)->offset + *offset) < get_varinfo (n)->fullsize; |
| 1507 | } |
| 1508 | |
| 1509 | /* Process a constraint C that represents x = *y, using DELTA as the |
| 1510 | starting solution. */ |
| 1511 | |
| 1512 | static void |
| 1513 | do_sd_constraint (constraint_graph_t graph, constraint_t c, |
| 1514 | bitmap delta) |
| 1515 | { |
| 1516 | unsigned int lhs = c->lhs.var; |
| 1517 | bool flag = false; |
| 1518 | bitmap sol = get_varinfo (lhs)->solution; |
| 1519 | unsigned int j; |
| 1520 | bitmap_iterator bi; |
| 1521 | |
| 1522 | /* For x = *ESCAPED and x = *CALLUSED we want to compute the |
| 1523 | reachability set of the rhs var. As a pointer to a sub-field |
| 1524 | of a variable can also reach all other fields of the variable |
| 1525 | we simply have to expand the solution to contain all sub-fields |
| 1526 | if one sub-field is contained. */ |
| 1527 | if (c->rhs.var == find (escaped_id) |
| 1528 | || c->rhs.var == find (callused_id)) |
| 1529 | { |
| 1530 | bitmap vars = NULL; |
| 1531 | /* In a first pass record all variables we need to add all |
| 1532 | sub-fields off. This avoids quadratic behavior. */ |
| 1533 | EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi) |
| 1534 | { |
| 1535 | varinfo_t v = get_varinfo (j); |
| 1536 | if (v->is_full_var) |
| 1537 | continue; |
| 1538 | |
| 1539 | v = lookup_vi_for_tree (v->decl); |
| 1540 | if (v->next != NULL) |
| 1541 | { |
| 1542 | if (vars == NULL) |
| 1543 | vars = BITMAP_ALLOC (NULL); |
| 1544 | bitmap_set_bit (vars, v->id); |
| 1545 | } |
| 1546 | } |
| 1547 | /* In the second pass now do the addition to the solution and |
| 1548 | to speed up solving add it to the delta as well. */ |
| 1549 | if (vars != NULL) |
| 1550 | { |
| 1551 | EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi) |
| 1552 | { |
| 1553 | varinfo_t v = get_varinfo (j); |
| 1554 | for (; v != NULL; v = v->next) |
| 1555 | { |
| 1556 | if (bitmap_set_bit (sol, v->id)) |
| 1557 | { |
| 1558 | flag = true; |
| 1559 | bitmap_set_bit (delta, v->id); |
| 1560 | } |
| 1561 | } |
| 1562 | } |
| 1563 | BITMAP_FREE (vars); |
| 1564 | } |
| 1565 | } |
| 1566 | |
| 1567 | if (bitmap_bit_p (delta, anything_id)) |
| 1568 | { |
| 1569 | flag |= bitmap_set_bit (sol, anything_id); |
| 1570 | goto done; |
| 1571 | } |
| 1572 | |
| 1573 | /* For each variable j in delta (Sol(y)), add |
| 1574 | an edge in the graph from j to x, and union Sol(j) into Sol(x). */ |
| 1575 | EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi) |
| 1576 | { |
| 1577 | unsigned HOST_WIDE_INT roffset = c->rhs.offset; |
| 1578 | if (type_safe (j, &roffset)) |
| 1579 | { |
| 1580 | varinfo_t v; |
| 1581 | unsigned HOST_WIDE_INT fieldoffset = get_varinfo (j)->offset + roffset; |
| 1582 | unsigned int t; |
| 1583 | |
| 1584 | v = first_vi_for_offset (get_varinfo (j), fieldoffset); |
| 1585 | /* If the access is outside of the variable we can ignore it. */ |
| 1586 | if (!v) |
| 1587 | continue; |
| 1588 | t = find (v->id); |
| 1589 | |
| 1590 | /* Adding edges from the special vars is pointless. |
| 1591 | They don't have sets that can change. */ |
| 1592 | if (get_varinfo (t)->is_special_var) |
| 1593 | flag |= bitmap_ior_into (sol, get_varinfo (t)->solution); |
| 1594 | /* Merging the solution from ESCAPED needlessly increases |
| 1595 | the set. Use ESCAPED as representative instead. |
| 1596 | Same for CALLUSED. */ |
| 1597 | else if (get_varinfo (t)->id == find (escaped_id)) |
| 1598 | flag |= bitmap_set_bit (sol, escaped_id); |
| 1599 | else if (get_varinfo (t)->id == find (callused_id)) |
| 1600 | flag |= bitmap_set_bit (sol, callused_id); |
| 1601 | else if (add_graph_edge (graph, lhs, t)) |
| 1602 | flag |= bitmap_ior_into (sol, get_varinfo (t)->solution); |
| 1603 | } |
| 1604 | } |
| 1605 | |
| 1606 | done: |
| 1607 | /* If the LHS solution changed, mark the var as changed. */ |
| 1608 | if (flag) |
| 1609 | { |
| 1610 | get_varinfo (lhs)->solution = sol; |
| 1611 | if (!TEST_BIT (changed, lhs)) |
| 1612 | { |
| 1613 | SET_BIT (changed, lhs); |
| 1614 | changed_count++; |
| 1615 | } |
| 1616 | } |
| 1617 | } |
| 1618 | |
| 1619 | /* Process a constraint C that represents *x = y. */ |
| 1620 | |
| 1621 | static void |
| 1622 | do_ds_constraint (constraint_t c, bitmap delta) |
| 1623 | { |
| 1624 | unsigned int rhs = c->rhs.var; |
| 1625 | bitmap sol = get_varinfo (rhs)->solution; |
| 1626 | unsigned int j; |
| 1627 | bitmap_iterator bi; |
| 1628 | |
| 1629 | /* Our IL does not allow this. */ |
| 1630 | gcc_assert (c->rhs.offset == 0); |
| 1631 | |
| 1632 | /* If the solution of y contains ANYTHING simply use the ANYTHING |
| 1633 | solution. This avoids needlessly increasing the points-to sets. */ |
| 1634 | if (bitmap_bit_p (sol, anything_id)) |
| 1635 | sol = get_varinfo (find (anything_id))->solution; |
| 1636 | |
| 1637 | /* If the solution for x contains ANYTHING we have to merge the |
| 1638 | solution of y into all pointer variables which we do via |
| 1639 | STOREDANYTHING. */ |
| 1640 | if (bitmap_bit_p (delta, anything_id)) |
| 1641 | { |
| 1642 | unsigned t = find (storedanything_id); |
| 1643 | if (add_graph_edge (graph, t, rhs)) |
| 1644 | { |
| 1645 | if (bitmap_ior_into (get_varinfo (t)->solution, sol)) |
| 1646 | { |
| 1647 | if (!TEST_BIT (changed, t)) |
| 1648 | { |
| 1649 | SET_BIT (changed, t); |
| 1650 | changed_count++; |
| 1651 | } |
| 1652 | } |
| 1653 | } |
| 1654 | return; |
| 1655 | } |
| 1656 | |
| 1657 | /* For each member j of delta (Sol(x)), add an edge from y to j and |
| 1658 | union Sol(y) into Sol(j) */ |
| 1659 | EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi) |
| 1660 | { |
| 1661 | unsigned HOST_WIDE_INT loff = c->lhs.offset; |
| 1662 | if (type_safe (j, &loff) && !(get_varinfo (j)->is_special_var)) |
| 1663 | { |
| 1664 | varinfo_t v; |
| 1665 | unsigned int t; |
| 1666 | unsigned HOST_WIDE_INT fieldoffset = get_varinfo (j)->offset + loff; |
| 1667 | |
| 1668 | v = first_vi_for_offset (get_varinfo (j), fieldoffset); |
| 1669 | /* If the access is outside of the variable we can ignore it. */ |
| 1670 | if (!v) |
| 1671 | continue; |
| 1672 | |
| 1673 | if (v->may_have_pointers) |
| 1674 | { |
| 1675 | t = find (v->id); |
| 1676 | if (add_graph_edge (graph, t, rhs)) |
| 1677 | { |
| 1678 | if (bitmap_ior_into (get_varinfo (t)->solution, sol)) |
| 1679 | { |
| 1680 | if (t == rhs) |
| 1681 | sol = get_varinfo (rhs)->solution; |
| 1682 | if (!TEST_BIT (changed, t)) |
| 1683 | { |
| 1684 | SET_BIT (changed, t); |
| 1685 | changed_count++; |
| 1686 | } |
| 1687 | } |
| 1688 | } |
| 1689 | } |
| 1690 | } |
| 1691 | } |
| 1692 | } |
| 1693 | |
| 1694 | /* Handle a non-simple (simple meaning requires no iteration), |
| 1695 | constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */ |
| 1696 | |
| 1697 | static void |
| 1698 | do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta) |
| 1699 | { |
| 1700 | if (c->lhs.type == DEREF) |
| 1701 | { |
| 1702 | if (c->rhs.type == ADDRESSOF) |
| 1703 | { |
| 1704 | gcc_unreachable(); |
| 1705 | } |
| 1706 | else |
| 1707 | { |
| 1708 | /* *x = y */ |
| 1709 | do_ds_constraint (c, delta); |
| 1710 | } |
| 1711 | } |
| 1712 | else if (c->rhs.type == DEREF) |
| 1713 | { |
| 1714 | /* x = *y */ |
| 1715 | if (!(get_varinfo (c->lhs.var)->is_special_var)) |
| 1716 | do_sd_constraint (graph, c, delta); |
| 1717 | } |
| 1718 | else |
| 1719 | { |
| 1720 | bitmap tmp; |
| 1721 | bitmap solution; |
| 1722 | bool flag = false; |
| 1723 | |
| 1724 | gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR); |
| 1725 | solution = get_varinfo (c->rhs.var)->solution; |
| 1726 | tmp = get_varinfo (c->lhs.var)->solution; |
| 1727 | |
| 1728 | flag = set_union_with_increment (tmp, solution, c->rhs.offset); |
| 1729 | |
| 1730 | if (flag) |
| 1731 | { |
| 1732 | get_varinfo (c->lhs.var)->solution = tmp; |
| 1733 | if (!TEST_BIT (changed, c->lhs.var)) |
| 1734 | { |
| 1735 | SET_BIT (changed, c->lhs.var); |
| 1736 | changed_count++; |
| 1737 | } |
| 1738 | } |
| 1739 | } |
| 1740 | } |
| 1741 | |
| 1742 | /* Initialize and return a new SCC info structure. */ |
| 1743 | |
| 1744 | static struct scc_info * |
| 1745 | init_scc_info (size_t size) |
| 1746 | { |
| 1747 | struct scc_info *si = XNEW (struct scc_info); |
| 1748 | size_t i; |
| 1749 | |
| 1750 | si->current_index = 0; |
| 1751 | si->visited = sbitmap_alloc (size); |
| 1752 | sbitmap_zero (si->visited); |
| 1753 | si->deleted = sbitmap_alloc (size); |
| 1754 | sbitmap_zero (si->deleted); |
| 1755 | si->node_mapping = XNEWVEC (unsigned int, size); |
| 1756 | si->dfs = XCNEWVEC (unsigned int, size); |
| 1757 | |
| 1758 | for (i = 0; i < size; i++) |
| 1759 | si->node_mapping[i] = i; |
| 1760 | |
| 1761 | si->scc_stack = VEC_alloc (unsigned, heap, 1); |
| 1762 | return si; |
| 1763 | } |
| 1764 | |
| 1765 | /* Free an SCC info structure pointed to by SI */ |
| 1766 | |
| 1767 | static void |
| 1768 | free_scc_info (struct scc_info *si) |
| 1769 | { |
| 1770 | sbitmap_free (si->visited); |
| 1771 | sbitmap_free (si->deleted); |
| 1772 | free (si->node_mapping); |
| 1773 | free (si->dfs); |
| 1774 | VEC_free (unsigned, heap, si->scc_stack); |
| 1775 | free (si); |
| 1776 | } |
| 1777 | |
| 1778 | |
| 1779 | /* Find indirect cycles in GRAPH that occur, using strongly connected |
| 1780 | components, and note them in the indirect cycles map. |
| 1781 | |
| 1782 | This technique comes from Ben Hardekopf and Calvin Lin, |
| 1783 | "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of |
| 1784 | Lines of Code", submitted to PLDI 2007. */ |
| 1785 | |
| 1786 | static void |
| 1787 | find_indirect_cycles (constraint_graph_t graph) |
| 1788 | { |
| 1789 | unsigned int i; |
| 1790 | unsigned int size = graph->size; |
| 1791 | struct scc_info *si = init_scc_info (size); |
| 1792 | |
| 1793 | for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ ) |
| 1794 | if (!TEST_BIT (si->visited, i) && find (i) == i) |
| 1795 | scc_visit (graph, si, i); |
| 1796 | |
| 1797 | free_scc_info (si); |
| 1798 | } |
| 1799 | |
| 1800 | /* Compute a topological ordering for GRAPH, and store the result in the |
| 1801 | topo_info structure TI. */ |
| 1802 | |
| 1803 | static void |
| 1804 | compute_topo_order (constraint_graph_t graph, |
| 1805 | struct topo_info *ti) |
| 1806 | { |
| 1807 | unsigned int i; |
| 1808 | unsigned int size = graph->size; |
| 1809 | |
| 1810 | for (i = 0; i != size; ++i) |
| 1811 | if (!TEST_BIT (ti->visited, i) && find (i) == i) |
| 1812 | topo_visit (graph, ti, i); |
| 1813 | } |
| 1814 | |
| 1815 | /* Structure used to for hash value numbering of pointer equivalence |
| 1816 | classes. */ |
| 1817 | |
| 1818 | typedef struct equiv_class_label |
| 1819 | { |
| 1820 | hashval_t hashcode; |
| 1821 | unsigned int equivalence_class; |
| 1822 | bitmap labels; |
| 1823 | } *equiv_class_label_t; |
| 1824 | typedef const struct equiv_class_label *const_equiv_class_label_t; |
| 1825 | |
| 1826 | /* A hashtable for mapping a bitmap of labels->pointer equivalence |
| 1827 | classes. */ |
| 1828 | static htab_t pointer_equiv_class_table; |
| 1829 | |
| 1830 | /* A hashtable for mapping a bitmap of labels->location equivalence |
| 1831 | classes. */ |
| 1832 | static htab_t location_equiv_class_table; |
| 1833 | |
| 1834 | /* Hash function for a equiv_class_label_t */ |
| 1835 | |
| 1836 | static hashval_t |
| 1837 | equiv_class_label_hash (const void *p) |
| 1838 | { |
| 1839 | const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p; |
| 1840 | return ecl->hashcode; |
| 1841 | } |
| 1842 | |
| 1843 | /* Equality function for two equiv_class_label_t's. */ |
| 1844 | |
| 1845 | static int |
| 1846 | equiv_class_label_eq (const void *p1, const void *p2) |
| 1847 | { |
| 1848 | const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1; |
| 1849 | const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2; |
| 1850 | return bitmap_equal_p (eql1->labels, eql2->labels); |
| 1851 | } |
| 1852 | |
| 1853 | /* Lookup a equivalence class in TABLE by the bitmap of LABELS it |
| 1854 | contains. */ |
| 1855 | |
| 1856 | static unsigned int |
| 1857 | equiv_class_lookup (htab_t table, bitmap labels) |
| 1858 | { |
| 1859 | void **slot; |
| 1860 | struct equiv_class_label ecl; |
| 1861 | |
| 1862 | ecl.labels = labels; |
| 1863 | ecl.hashcode = bitmap_hash (labels); |
| 1864 | |
| 1865 | slot = htab_find_slot_with_hash (table, &ecl, |
| 1866 | ecl.hashcode, NO_INSERT); |
| 1867 | if (!slot) |
| 1868 | return 0; |
| 1869 | else |
| 1870 | return ((equiv_class_label_t) *slot)->equivalence_class; |
| 1871 | } |
| 1872 | |
| 1873 | |
| 1874 | /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS |
| 1875 | to TABLE. */ |
| 1876 | |
| 1877 | static void |
| 1878 | equiv_class_add (htab_t table, unsigned int equivalence_class, |
| 1879 | bitmap labels) |
| 1880 | { |
| 1881 | void **slot; |
| 1882 | equiv_class_label_t ecl = XNEW (struct equiv_class_label); |
| 1883 | |
| 1884 | ecl->labels = labels; |
| 1885 | ecl->equivalence_class = equivalence_class; |
| 1886 | ecl->hashcode = bitmap_hash (labels); |
| 1887 | |
| 1888 | slot = htab_find_slot_with_hash (table, ecl, |
| 1889 | ecl->hashcode, INSERT); |
| 1890 | gcc_assert (!*slot); |
| 1891 | *slot = (void *) ecl; |
| 1892 | } |
| 1893 | |
| 1894 | /* Perform offline variable substitution. |
| 1895 | |
| 1896 | This is a worst case quadratic time way of identifying variables |
| 1897 | that must have equivalent points-to sets, including those caused by |
| 1898 | static cycles, and single entry subgraphs, in the constraint graph. |
| 1899 | |
| 1900 | The technique is described in "Exploiting Pointer and Location |
| 1901 | Equivalence to Optimize Pointer Analysis. In the 14th International |
| 1902 | Static Analysis Symposium (SAS), August 2007." It is known as the |
| 1903 | "HU" algorithm, and is equivalent to value numbering the collapsed |
| 1904 | constraint graph including evaluating unions. |
| 1905 | |
| 1906 | The general method of finding equivalence classes is as follows: |
| 1907 | Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints. |
| 1908 | Initialize all non-REF nodes to be direct nodes. |
| 1909 | For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh |
| 1910 | variable} |
| 1911 | For each constraint containing the dereference, we also do the same |
| 1912 | thing. |
| 1913 | |
| 1914 | We then compute SCC's in the graph and unify nodes in the same SCC, |
| 1915 | including pts sets. |
| 1916 | |
| 1917 | For each non-collapsed node x: |
| 1918 | Visit all unvisited explicit incoming edges. |
| 1919 | Ignoring all non-pointers, set pts(x) = Union of pts(a) for y |
| 1920 | where y->x. |
| 1921 | Lookup the equivalence class for pts(x). |
| 1922 | If we found one, equivalence_class(x) = found class. |
| 1923 | Otherwise, equivalence_class(x) = new class, and new_class is |
| 1924 | added to the lookup table. |
| 1925 | |
| 1926 | All direct nodes with the same equivalence class can be replaced |
| 1927 | with a single representative node. |
| 1928 | All unlabeled nodes (label == 0) are not pointers and all edges |
| 1929 | involving them can be eliminated. |
| 1930 | We perform these optimizations during rewrite_constraints |
| 1931 | |
| 1932 | In addition to pointer equivalence class finding, we also perform |
| 1933 | location equivalence class finding. This is the set of variables |
| 1934 | that always appear together in points-to sets. We use this to |
| 1935 | compress the size of the points-to sets. */ |
| 1936 | |
| 1937 | /* Current maximum pointer equivalence class id. */ |
| 1938 | static int pointer_equiv_class; |
| 1939 | |
| 1940 | /* Current maximum location equivalence class id. */ |
| 1941 | static int location_equiv_class; |
| 1942 | |
| 1943 | /* Recursive routine to find strongly connected components in GRAPH, |
| 1944 | and label it's nodes with DFS numbers. */ |
| 1945 | |
| 1946 | static void |
| 1947 | condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n) |
| 1948 | { |
| 1949 | unsigned int i; |
| 1950 | bitmap_iterator bi; |
| 1951 | unsigned int my_dfs; |
| 1952 | |
| 1953 | gcc_assert (si->node_mapping[n] == n); |
| 1954 | SET_BIT (si->visited, n); |
| 1955 | si->dfs[n] = si->current_index ++; |
| 1956 | my_dfs = si->dfs[n]; |
| 1957 | |
| 1958 | /* Visit all the successors. */ |
| 1959 | EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi) |
| 1960 | { |
| 1961 | unsigned int w = si->node_mapping[i]; |
| 1962 | |
| 1963 | if (TEST_BIT (si->deleted, w)) |
| 1964 | continue; |
| 1965 | |
| 1966 | if (!TEST_BIT (si->visited, w)) |
| 1967 | condense_visit (graph, si, w); |
| 1968 | { |
| 1969 | unsigned int t = si->node_mapping[w]; |
| 1970 | unsigned int nnode = si->node_mapping[n]; |
| 1971 | gcc_assert (nnode == n); |
| 1972 | |
| 1973 | if (si->dfs[t] < si->dfs[nnode]) |
| 1974 | si->dfs[n] = si->dfs[t]; |
| 1975 | } |
| 1976 | } |
| 1977 | |
| 1978 | /* Visit all the implicit predecessors. */ |
| 1979 | EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi) |
| 1980 | { |
| 1981 | unsigned int w = si->node_mapping[i]; |
| 1982 | |
| 1983 | if (TEST_BIT (si->deleted, w)) |
| 1984 | continue; |
| 1985 | |
| 1986 | if (!TEST_BIT (si->visited, w)) |
| 1987 | condense_visit (graph, si, w); |
| 1988 | { |
| 1989 | unsigned int t = si->node_mapping[w]; |
| 1990 | unsigned int nnode = si->node_mapping[n]; |
| 1991 | gcc_assert (nnode == n); |
| 1992 | |
| 1993 | if (si->dfs[t] < si->dfs[nnode]) |
| 1994 | si->dfs[n] = si->dfs[t]; |
| 1995 | } |
| 1996 | } |
| 1997 | |
| 1998 | /* See if any components have been identified. */ |
| 1999 | if (si->dfs[n] == my_dfs) |
| 2000 | { |
| 2001 | while (VEC_length (unsigned, si->scc_stack) != 0 |
| 2002 | && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs) |
| 2003 | { |
| 2004 | unsigned int w = VEC_pop (unsigned, si->scc_stack); |
| 2005 | si->node_mapping[w] = n; |
| 2006 | |
| 2007 | if (!TEST_BIT (graph->direct_nodes, w)) |
| 2008 | RESET_BIT (graph->direct_nodes, n); |
| 2009 | |
| 2010 | /* Unify our nodes. */ |
| 2011 | if (graph->preds[w]) |
| 2012 | { |
| 2013 | if (!graph->preds[n]) |
| 2014 | graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack); |
| 2015 | bitmap_ior_into (graph->preds[n], graph->preds[w]); |
| 2016 | } |
| 2017 | if (graph->implicit_preds[w]) |
| 2018 | { |
| 2019 | if (!graph->implicit_preds[n]) |
| 2020 | graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack); |
| 2021 | bitmap_ior_into (graph->implicit_preds[n], |
| 2022 | graph->implicit_preds[w]); |
| 2023 | } |
| 2024 | if (graph->points_to[w]) |
| 2025 | { |
| 2026 | if (!graph->points_to[n]) |
| 2027 | graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack); |
| 2028 | bitmap_ior_into (graph->points_to[n], |
| 2029 | graph->points_to[w]); |
| 2030 | } |
| 2031 | } |
| 2032 | SET_BIT (si->deleted, n); |
| 2033 | } |
| 2034 | else |
| 2035 | VEC_safe_push (unsigned, heap, si->scc_stack, n); |
| 2036 | } |
| 2037 | |
| 2038 | /* Label pointer equivalences. */ |
| 2039 | |
| 2040 | static void |
| 2041 | label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n) |
| 2042 | { |
| 2043 | unsigned int i; |
| 2044 | bitmap_iterator bi; |
| 2045 | SET_BIT (si->visited, n); |
| 2046 | |
| 2047 | if (!graph->points_to[n]) |
| 2048 | graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack); |
| 2049 | |
| 2050 | /* Label and union our incoming edges's points to sets. */ |
| 2051 | EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi) |
| 2052 | { |
| 2053 | unsigned int w = si->node_mapping[i]; |
| 2054 | if (!TEST_BIT (si->visited, w)) |
| 2055 | label_visit (graph, si, w); |
| 2056 | |
| 2057 | /* Skip unused edges */ |
| 2058 | if (w == n || graph->pointer_label[w] == 0) |
| 2059 | continue; |
| 2060 | |
| 2061 | if (graph->points_to[w]) |
| 2062 | bitmap_ior_into(graph->points_to[n], graph->points_to[w]); |
| 2063 | } |
| 2064 | /* Indirect nodes get fresh variables. */ |
| 2065 | if (!TEST_BIT (graph->direct_nodes, n)) |
| 2066 | bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n); |
| 2067 | |
| 2068 | if (!bitmap_empty_p (graph->points_to[n])) |
| 2069 | { |
| 2070 | unsigned int label = equiv_class_lookup (pointer_equiv_class_table, |
| 2071 | graph->points_to[n]); |
| 2072 | if (!label) |
| 2073 | { |
| 2074 | label = pointer_equiv_class++; |
| 2075 | equiv_class_add (pointer_equiv_class_table, |
| 2076 | label, graph->points_to[n]); |
| 2077 | } |
| 2078 | graph->pointer_label[n] = label; |
| 2079 | } |
| 2080 | } |
| 2081 | |
| 2082 | /* Perform offline variable substitution, discovering equivalence |
| 2083 | classes, and eliminating non-pointer variables. */ |
| 2084 | |
| 2085 | static struct scc_info * |
| 2086 | perform_var_substitution (constraint_graph_t graph) |
| 2087 | { |
| 2088 | unsigned int i; |
| 2089 | unsigned int size = graph->size; |
| 2090 | struct scc_info *si = init_scc_info (size); |
| 2091 | |
| 2092 | bitmap_obstack_initialize (&iteration_obstack); |
| 2093 | pointer_equiv_class_table = htab_create (511, equiv_class_label_hash, |
| 2094 | equiv_class_label_eq, free); |
| 2095 | location_equiv_class_table = htab_create (511, equiv_class_label_hash, |
| 2096 | equiv_class_label_eq, free); |
| 2097 | pointer_equiv_class = 1; |
| 2098 | location_equiv_class = 1; |
| 2099 | |
| 2100 | /* Condense the nodes, which means to find SCC's, count incoming |
| 2101 | predecessors, and unite nodes in SCC's. */ |
| 2102 | for (i = 0; i < FIRST_REF_NODE; i++) |
| 2103 | if (!TEST_BIT (si->visited, si->node_mapping[i])) |
| 2104 | condense_visit (graph, si, si->node_mapping[i]); |
| 2105 | |
| 2106 | sbitmap_zero (si->visited); |
| 2107 | /* Actually the label the nodes for pointer equivalences */ |
| 2108 | for (i = 0; i < FIRST_REF_NODE; i++) |
| 2109 | if (!TEST_BIT (si->visited, si->node_mapping[i])) |
| 2110 | label_visit (graph, si, si->node_mapping[i]); |
| 2111 | |
| 2112 | /* Calculate location equivalence labels. */ |
| 2113 | for (i = 0; i < FIRST_REF_NODE; i++) |
| 2114 | { |
| 2115 | bitmap pointed_by; |
| 2116 | bitmap_iterator bi; |
| 2117 | unsigned int j; |
| 2118 | unsigned int label; |
| 2119 | |
| 2120 | if (!graph->pointed_by[i]) |
| 2121 | continue; |
| 2122 | pointed_by = BITMAP_ALLOC (&iteration_obstack); |
| 2123 | |
| 2124 | /* Translate the pointed-by mapping for pointer equivalence |
| 2125 | labels. */ |
| 2126 | EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi) |
| 2127 | { |
| 2128 | bitmap_set_bit (pointed_by, |
| 2129 | graph->pointer_label[si->node_mapping[j]]); |
| 2130 | } |
| 2131 | /* The original pointed_by is now dead. */ |
| 2132 | BITMAP_FREE (graph->pointed_by[i]); |
| 2133 | |
| 2134 | /* Look up the location equivalence label if one exists, or make |
| 2135 | one otherwise. */ |
| 2136 | label = equiv_class_lookup (location_equiv_class_table, |
| 2137 | pointed_by); |
| 2138 | if (label == 0) |
| 2139 | { |
| 2140 | label = location_equiv_class++; |
| 2141 | equiv_class_add (location_equiv_class_table, |
| 2142 | label, pointed_by); |
| 2143 | } |
| 2144 | else |
| 2145 | { |
| 2146 | if (dump_file && (dump_flags & TDF_DETAILS)) |
| 2147 | fprintf (dump_file, "Found location equivalence for node %s\n", |
| 2148 | get_varinfo (i)->name); |
| 2149 | BITMAP_FREE (pointed_by); |
| 2150 | } |
| 2151 | graph->loc_label[i] = label; |
| 2152 | |
| 2153 | } |
| 2154 | |
| 2155 | if (dump_file && (dump_flags & TDF_DETAILS)) |
| 2156 | for (i = 0; i < FIRST_REF_NODE; i++) |
| 2157 | { |
| 2158 | bool direct_node = TEST_BIT (graph->direct_nodes, i); |
| 2159 | fprintf (dump_file, |
| 2160 | "Equivalence classes for %s node id %d:%s are pointer: %d" |
| 2161 | ", location:%d\n", |
| 2162 | direct_node ? "Direct node" : "Indirect node", i, |
| 2163 | get_varinfo (i)->name, |
| 2164 | graph->pointer_label[si->node_mapping[i]], |
| 2165 | graph->loc_label[si->node_mapping[i]]); |
| 2166 | } |
| 2167 | |
| 2168 | /* Quickly eliminate our non-pointer variables. */ |
| 2169 | |
| 2170 | for (i = 0; i < FIRST_REF_NODE; i++) |
| 2171 | { |
| 2172 | unsigned int node = si->node_mapping[i]; |
| 2173 | |
| 2174 | if (graph->pointer_label[node] == 0) |
| 2175 | { |
| 2176 | if (dump_file && (dump_flags & TDF_DETAILS)) |
| 2177 | fprintf (dump_file, |
| 2178 | "%s is a non-pointer variable, eliminating edges.\n", |
| 2179 | get_varinfo (node)->name); |
| 2180 | stats.nonpointer_vars++; |
| 2181 | clear_edges_for_node (graph, node); |
| 2182 | } |
| 2183 | } |
| 2184 | |
| 2185 | return si; |
| 2186 | } |
| 2187 | |
| 2188 | /* Free information that was only necessary for variable |
| 2189 | substitution. */ |
| 2190 | |
| 2191 | static void |
| 2192 | free_var_substitution_info (struct scc_info *si) |
| 2193 | { |
| 2194 | free_scc_info (si); |
| 2195 | free (graph->pointer_label); |
| 2196 | free (graph->loc_label); |
| 2197 | free (graph->pointed_by); |
| 2198 | free (graph->points_to); |
| 2199 | free (graph->eq_rep); |
| 2200 | sbitmap_free (graph->direct_nodes); |
| 2201 | htab_delete (pointer_equiv_class_table); |
| 2202 | htab_delete (location_equiv_class_table); |
| 2203 | bitmap_obstack_release (&iteration_obstack); |
| 2204 | } |
| 2205 | |
| 2206 | /* Return an existing node that is equivalent to NODE, which has |
| 2207 | equivalence class LABEL, if one exists. Return NODE otherwise. */ |
| 2208 | |
| 2209 | static unsigned int |
| 2210 | find_equivalent_node (constraint_graph_t graph, |
| 2211 | unsigned int node, unsigned int label) |
| 2212 | { |
| 2213 | /* If the address version of this variable is unused, we can |
| 2214 | substitute it for anything else with the same label. |
| 2215 | Otherwise, we know the pointers are equivalent, but not the |
| 2216 | locations, and we can unite them later. */ |
| 2217 | |
| 2218 | if (!bitmap_bit_p (graph->address_taken, node)) |
| 2219 | { |
| 2220 | gcc_assert (label < graph->size); |
| 2221 | |
| 2222 | if (graph->eq_rep[label] != -1) |
| 2223 | { |
| 2224 | /* Unify the two variables since we know they are equivalent. */ |
| 2225 | if (unite (graph->eq_rep[label], node)) |
| 2226 | unify_nodes (graph, graph->eq_rep[label], node, false); |
| 2227 | return graph->eq_rep[label]; |
| 2228 | } |
| 2229 | else |
| 2230 | { |
| 2231 | graph->eq_rep[label] = node; |
| 2232 | graph->pe_rep[label] = node; |
| 2233 | } |
| 2234 | } |
| 2235 | else |
| 2236 | { |
| 2237 | gcc_assert (label < graph->size); |
| 2238 | graph->pe[node] = label; |
| 2239 | if (graph->pe_rep[label] == -1) |
| 2240 | graph->pe_rep[label] = node; |
| 2241 | } |
| 2242 | |
| 2243 | return node; |
| 2244 | } |
| 2245 | |
| 2246 | /* Unite pointer equivalent but not location equivalent nodes in |
| 2247 | GRAPH. This may only be performed once variable substitution is |
| 2248 | finished. */ |
| 2249 | |
| 2250 | static void |
| 2251 | unite_pointer_equivalences (constraint_graph_t graph) |
| 2252 | { |
| 2253 | unsigned int i; |
| 2254 | |
| 2255 | /* Go through the pointer equivalences and unite them to their |
| 2256 | representative, if they aren't already. */ |
| 2257 | for (i = 0; i < FIRST_REF_NODE; i++) |
| 2258 | { |
| 2259 | unsigned int label = graph->pe[i]; |
| 2260 | if (label) |
| 2261 | { |
| 2262 | int label_rep = graph->pe_rep[label]; |
| 2263 | |
| 2264 | if (label_rep == -1) |
| 2265 | continue; |
| 2266 | |
| 2267 | label_rep = find (label_rep); |
| 2268 | if (label_rep >= 0 && unite (label_rep, find (i))) |
| 2269 | unify_nodes (graph, label_rep, i, false); |
| 2270 | } |
| 2271 | } |
| 2272 | } |
| 2273 | |
| 2274 | /* Move complex constraints to the GRAPH nodes they belong to. */ |
| 2275 | |
| 2276 | static void |
| 2277 | move_complex_constraints (constraint_graph_t graph) |
| 2278 | { |
| 2279 | int i; |
| 2280 | constraint_t c; |
| 2281 | |
| 2282 | for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++) |
| 2283 | { |
| 2284 | if (c) |
| 2285 | { |
| 2286 | struct constraint_expr lhs = c->lhs; |
| 2287 | struct constraint_expr rhs = c->rhs; |
| 2288 | |
| 2289 | if (lhs.type == DEREF) |
| 2290 | { |
| 2291 | insert_into_complex (graph, lhs.var, c); |
| 2292 | } |
| 2293 | else if (rhs.type == DEREF) |
| 2294 | { |
| 2295 | if (!(get_varinfo (lhs.var)->is_special_var)) |
| 2296 | insert_into_complex (graph, rhs.var, c); |
| 2297 | } |
| 2298 | else if (rhs.type != ADDRESSOF && lhs.var > anything_id |
| 2299 | && (lhs.offset != 0 || rhs.offset != 0)) |
| 2300 | { |
| 2301 | insert_into_complex (graph, rhs.var, c); |
| 2302 | } |
| 2303 | } |
| 2304 | } |
| 2305 | } |
| 2306 | |
| 2307 | |
| 2308 | /* Optimize and rewrite complex constraints while performing |
| 2309 | collapsing of equivalent nodes. SI is the SCC_INFO that is the |
| 2310 | result of perform_variable_substitution. */ |
| 2311 | |
| 2312 | static void |
| 2313 | rewrite_constraints (constraint_graph_t graph, |
| 2314 | struct scc_info *si) |
| 2315 | { |
| 2316 | int i; |
| 2317 | unsigned int j; |
| 2318 | constraint_t c; |
| 2319 | |
| 2320 | for (j = 0; j < graph->size; j++) |
| 2321 | gcc_assert (find (j) == j); |
| 2322 | |
| 2323 | for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++) |
| 2324 | { |
| 2325 | struct constraint_expr lhs = c->lhs; |
| 2326 | struct constraint_expr rhs = c->rhs; |
| 2327 | unsigned int lhsvar = find (get_varinfo_fc (lhs.var)->id); |
| 2328 | unsigned int rhsvar = find (get_varinfo_fc (rhs.var)->id); |
| 2329 | unsigned int lhsnode, rhsnode; |
| 2330 | unsigned int lhslabel, rhslabel; |
| 2331 | |
| 2332 | lhsnode = si->node_mapping[lhsvar]; |
| 2333 | rhsnode = si->node_mapping[rhsvar]; |
| 2334 | lhslabel = graph->pointer_label[lhsnode]; |
| 2335 | rhslabel = graph->pointer_label[rhsnode]; |
| 2336 | |
| 2337 | /* See if it is really a non-pointer variable, and if so, ignore |
| 2338 | the constraint. */ |
| 2339 | if (lhslabel == 0) |
| 2340 | { |
| 2341 | if (dump_file && (dump_flags & TDF_DETAILS)) |
| 2342 | { |
| 2343 | |
| 2344 | fprintf (dump_file, "%s is a non-pointer variable," |
| 2345 | "ignoring constraint:", |
| 2346 | get_varinfo (lhs.var)->name); |
| 2347 | dump_constraint (dump_file, c); |
| 2348 | } |
| 2349 | VEC_replace (constraint_t, constraints, i, NULL); |
| 2350 | continue; |
| 2351 | } |
| 2352 | |
| 2353 | if (rhslabel == 0) |
| 2354 | { |
| 2355 | if (dump_file && (dump_flags & TDF_DETAILS)) |
| 2356 | { |
| 2357 | |
| 2358 | fprintf (dump_file, "%s is a non-pointer variable," |
| 2359 | "ignoring constraint:", |
| 2360 | get_varinfo (rhs.var)->name); |
| 2361 | dump_constraint (dump_file, c); |
| 2362 | } |
| 2363 | VEC_replace (constraint_t, constraints, i, NULL); |
| 2364 | continue; |
| 2365 | } |
| 2366 | |
| 2367 | lhsvar = find_equivalent_node (graph, lhsvar, lhslabel); |
| 2368 | rhsvar = find_equivalent_node (graph, rhsvar, rhslabel); |
| 2369 | c->lhs.var = lhsvar; |
| 2370 | c->rhs.var = rhsvar; |
| 2371 | |
| 2372 | } |
| 2373 | } |
| 2374 | |
| 2375 | /* Eliminate indirect cycles involving NODE. Return true if NODE was |
| 2376 | part of an SCC, false otherwise. */ |
| 2377 | |
| 2378 | static bool |
| 2379 | eliminate_indirect_cycles (unsigned int node) |
| 2380 | { |
| 2381 | if (graph->indirect_cycles[node] != -1 |
| 2382 | && !bitmap_empty_p (get_varinfo (node)->solution)) |
| 2383 | { |
| 2384 | unsigned int i; |
| 2385 | VEC(unsigned,heap) *queue = NULL; |
| 2386 | int queuepos; |
| 2387 | unsigned int to = find (graph->indirect_cycles[node]); |
| 2388 | bitmap_iterator bi; |
| 2389 | |
| 2390 | /* We can't touch the solution set and call unify_nodes |
| 2391 | at the same time, because unify_nodes is going to do |
| 2392 | bitmap unions into it. */ |
| 2393 | |
| 2394 | EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi) |
| 2395 | { |
| 2396 | if (find (i) == i && i != to) |
| 2397 | { |
| 2398 | if (unite (to, i)) |
| 2399 | VEC_safe_push (unsigned, heap, queue, i); |
| 2400 | } |
| 2401 | } |
| 2402 | |
| 2403 | for (queuepos = 0; |
| 2404 | VEC_iterate (unsigned, queue, queuepos, i); |
| 2405 | queuepos++) |
| 2406 | { |
| 2407 | unify_nodes (graph, to, i, true); |
| 2408 | } |
| 2409 | VEC_free (unsigned, heap, queue); |
| 2410 | return true; |
| 2411 | } |
| 2412 | return false; |
| 2413 | } |
| 2414 | |
| 2415 | /* Solve the constraint graph GRAPH using our worklist solver. |
| 2416 | This is based on the PW* family of solvers from the "Efficient Field |
| 2417 | Sensitive Pointer Analysis for C" paper. |
| 2418 | It works by iterating over all the graph nodes, processing the complex |
| 2419 | constraints and propagating the copy constraints, until everything stops |
| 2420 | changed. This corresponds to steps 6-8 in the solving list given above. */ |
| 2421 | |
| 2422 | static void |
| 2423 | solve_graph (constraint_graph_t graph) |
| 2424 | { |
| 2425 | unsigned int size = graph->size; |
| 2426 | unsigned int i; |
| 2427 | bitmap pts; |
| 2428 | |
| 2429 | changed_count = 0; |
| 2430 | changed = sbitmap_alloc (size); |
| 2431 | sbitmap_zero (changed); |
| 2432 | |
| 2433 | /* Mark all initial non-collapsed nodes as changed. */ |
| 2434 | for (i = 0; i < size; i++) |
| 2435 | { |
| 2436 | varinfo_t ivi = get_varinfo (i); |
| 2437 | if (find (i) == i && !bitmap_empty_p (ivi->solution) |
| 2438 | && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i])) |
| 2439 | || VEC_length (constraint_t, graph->complex[i]) > 0)) |
| 2440 | { |
| 2441 | SET_BIT (changed, i); |
| 2442 | changed_count++; |
| 2443 | } |
| 2444 | } |
| 2445 | |
| 2446 | /* Allocate a bitmap to be used to store the changed bits. */ |
| 2447 | pts = BITMAP_ALLOC (&pta_obstack); |
| 2448 | |
| 2449 | while (changed_count > 0) |
| 2450 | { |
| 2451 | unsigned int i; |
| 2452 | struct topo_info *ti = init_topo_info (); |
| 2453 | stats.iterations++; |
| 2454 | |
| 2455 | bitmap_obstack_initialize (&iteration_obstack); |
| 2456 | |
| 2457 | compute_topo_order (graph, ti); |
| 2458 | |
| 2459 | while (VEC_length (unsigned, ti->topo_order) != 0) |
| 2460 | { |
| 2461 | |
| 2462 | i = VEC_pop (unsigned, ti->topo_order); |
| 2463 | |
| 2464 | /* If this variable is not a representative, skip it. */ |
| 2465 | if (find (i) != i) |
| 2466 | continue; |
| 2467 | |
| 2468 | /* In certain indirect cycle cases, we may merge this |
| 2469 | variable to another. */ |
| 2470 | if (eliminate_indirect_cycles (i) && find (i) != i) |
| 2471 | continue; |
| 2472 | |
| 2473 | /* If the node has changed, we need to process the |
| 2474 | complex constraints and outgoing edges again. */ |
| 2475 | if (TEST_BIT (changed, i)) |
| 2476 | { |
| 2477 | unsigned int j; |
| 2478 | constraint_t c; |
| 2479 | bitmap solution; |
| 2480 | VEC(constraint_t,heap) *complex = graph->complex[i]; |
| 2481 | bool solution_empty; |
| 2482 | |
| 2483 | RESET_BIT (changed, i); |
| 2484 | changed_count--; |
| 2485 | |
| 2486 | /* Compute the changed set of solution bits. */ |
| 2487 | bitmap_and_compl (pts, get_varinfo (i)->solution, |
| 2488 | get_varinfo (i)->oldsolution); |
| 2489 | |
| 2490 | if (bitmap_empty_p (pts)) |
| 2491 | continue; |
| 2492 | |
| 2493 | bitmap_ior_into (get_varinfo (i)->oldsolution, pts); |
| 2494 | |
| 2495 | solution = get_varinfo (i)->solution; |
| 2496 | solution_empty = bitmap_empty_p (solution); |
| 2497 | |
| 2498 | /* Process the complex constraints */ |
| 2499 | for (j = 0; VEC_iterate (constraint_t, complex, j, c); j++) |
| 2500 | { |
| 2501 | /* XXX: This is going to unsort the constraints in |
| 2502 | some cases, which will occasionally add duplicate |
| 2503 | constraints during unification. This does not |
| 2504 | affect correctness. */ |
| 2505 | c->lhs.var = find (c->lhs.var); |
| 2506 | c->rhs.var = find (c->rhs.var); |
| 2507 | |
| 2508 | /* The only complex constraint that can change our |
| 2509 | solution to non-empty, given an empty solution, |
| 2510 | is a constraint where the lhs side is receiving |
| 2511 | some set from elsewhere. */ |
| 2512 | if (!solution_empty || c->lhs.type != DEREF) |
| 2513 | do_complex_constraint (graph, c, pts); |
| 2514 | } |
| 2515 | |
| 2516 | solution_empty = bitmap_empty_p (solution); |
| 2517 | |
| 2518 | if (!solution_empty |
| 2519 | /* Do not propagate the ESCAPED/CALLUSED solutions. */ |
| 2520 | && i != find (escaped_id) |
| 2521 | && i != find (callused_id)) |
| 2522 | { |
| 2523 | bitmap_iterator bi; |
| 2524 | |
| 2525 | /* Propagate solution to all successors. */ |
| 2526 | EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i], |
| 2527 | 0, j, bi) |
| 2528 | { |
| 2529 | bitmap tmp; |
| 2530 | bool flag; |
| 2531 | |
| 2532 | unsigned int to = find (j); |
| 2533 | tmp = get_varinfo (to)->solution; |
| 2534 | flag = false; |
| 2535 | |
| 2536 | /* Don't try to propagate to ourselves. */ |
| 2537 | if (to == i) |
| 2538 | continue; |
| 2539 | |
| 2540 | flag = set_union_with_increment (tmp, pts, 0); |
| 2541 | |
| 2542 | if (flag) |
| 2543 | { |
| 2544 | get_varinfo (to)->solution = tmp; |
| 2545 | if (!TEST_BIT (changed, to)) |
| 2546 | { |
| 2547 | SET_BIT (changed, to); |
| 2548 | changed_count++; |
| 2549 | } |
| 2550 | } |
| 2551 | } |
| 2552 | } |
| 2553 | } |
| 2554 | } |
| 2555 | free_topo_info (ti); |
| 2556 | bitmap_obstack_release (&iteration_obstack); |
| 2557 | } |
| 2558 | |
| 2559 | BITMAP_FREE (pts); |
| 2560 | sbitmap_free (changed); |
| 2561 | bitmap_obstack_release (&oldpta_obstack); |
| 2562 | } |
| 2563 | |
| 2564 | /* Map from trees to variable infos. */ |
| 2565 | static struct pointer_map_t *vi_for_tree; |
| 2566 | |
| 2567 | |
| 2568 | /* Insert ID as the variable id for tree T in the vi_for_tree map. */ |
| 2569 | |
| 2570 | static void |
| 2571 | insert_vi_for_tree (tree t, varinfo_t vi) |
| 2572 | { |
| 2573 | void **slot = pointer_map_insert (vi_for_tree, t); |
| 2574 | gcc_assert (vi); |
| 2575 | gcc_assert (*slot == NULL); |
| 2576 | *slot = vi; |
| 2577 | } |
| 2578 | |
| 2579 | /* Find the variable info for tree T in VI_FOR_TREE. If T does not |
| 2580 | exist in the map, return NULL, otherwise, return the varinfo we found. */ |
| 2581 | |
| 2582 | static varinfo_t |
| 2583 | lookup_vi_for_tree (tree t) |
| 2584 | { |
| 2585 | void **slot = pointer_map_contains (vi_for_tree, t); |
| 2586 | if (slot == NULL) |
| 2587 | return NULL; |
| 2588 | |
| 2589 | return (varinfo_t) *slot; |
| 2590 | } |
| 2591 | |
| 2592 | /* Return a printable name for DECL */ |
| 2593 | |
| 2594 | static const char * |
| 2595 | alias_get_name (tree decl) |
| 2596 | { |
| 2597 | const char *res = get_name (decl); |
| 2598 | char *temp; |
| 2599 | int num_printed = 0; |
| 2600 | |
| 2601 | if (res != NULL) |
| 2602 | return res; |
| 2603 | |
| 2604 | res = "NULL"; |
| 2605 | if (!dump_file) |
| 2606 | return res; |
| 2607 | |
| 2608 | if (TREE_CODE (decl) == SSA_NAME) |
| 2609 | { |
| 2610 | num_printed = asprintf (&temp, "%s_%u", |
| 2611 | alias_get_name (SSA_NAME_VAR (decl)), |
| 2612 | SSA_NAME_VERSION (decl)); |
| 2613 | } |
| 2614 | else if (DECL_P (decl)) |
| 2615 | { |
| 2616 | num_printed = asprintf (&temp, "D.%u", DECL_UID (decl)); |
| 2617 | } |
| 2618 | if (num_printed > 0) |
| 2619 | { |
| 2620 | res = ggc_strdup (temp); |
| 2621 | free (temp); |
| 2622 | } |
| 2623 | return res; |
| 2624 | } |
| 2625 | |
| 2626 | /* Find the variable id for tree T in the map. |
| 2627 | If T doesn't exist in the map, create an entry for it and return it. */ |
| 2628 | |
| 2629 | static varinfo_t |
| 2630 | get_vi_for_tree (tree t) |
| 2631 | { |
| 2632 | void **slot = pointer_map_contains (vi_for_tree, t); |
| 2633 | if (slot == NULL) |
| 2634 | return get_varinfo (create_variable_info_for (t, alias_get_name (t))); |
| 2635 | |
| 2636 | return (varinfo_t) *slot; |
| 2637 | } |
| 2638 | |
| 2639 | /* Get a constraint expression for a new temporary variable. */ |
| 2640 | |
| 2641 | static struct constraint_expr |
| 2642 | get_constraint_exp_for_temp (tree t) |
| 2643 | { |
| 2644 | struct constraint_expr cexpr; |
| 2645 | |
| 2646 | gcc_assert (SSA_VAR_P (t)); |
| 2647 | |
| 2648 | cexpr.type = SCALAR; |
| 2649 | cexpr.var = get_vi_for_tree (t)->id; |
| 2650 | cexpr.offset = 0; |
| 2651 | |
| 2652 | return cexpr; |
| 2653 | } |
| 2654 | |
| 2655 | /* Get a constraint expression vector from an SSA_VAR_P node. |
| 2656 | If address_p is true, the result will be taken its address of. */ |
| 2657 | |
| 2658 | static void |
| 2659 | get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p) |
| 2660 | { |
| 2661 | struct constraint_expr cexpr; |
| 2662 | varinfo_t vi; |
| 2663 | |
| 2664 | /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */ |
| 2665 | gcc_assert (SSA_VAR_P (t) || DECL_P (t)); |
| 2666 | |
| 2667 | /* For parameters, get at the points-to set for the actual parm |
| 2668 | decl. */ |
| 2669 | if (TREE_CODE (t) == SSA_NAME |
| 2670 | && TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL |
| 2671 | && SSA_NAME_IS_DEFAULT_DEF (t)) |
| 2672 | { |
| 2673 | get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p); |
| 2674 | return; |
| 2675 | } |
| 2676 | |
| 2677 | vi = get_vi_for_tree (t); |
| 2678 | cexpr.var = vi->id; |
| 2679 | cexpr.type = SCALAR; |
| 2680 | cexpr.offset = 0; |
| 2681 | /* If we determine the result is "anything", and we know this is readonly, |
| 2682 | say it points to readonly memory instead. */ |
| 2683 | if (cexpr.var == anything_id && TREE_READONLY (t)) |
| 2684 | { |
| 2685 | gcc_unreachable (); |
| 2686 | cexpr.type = ADDRESSOF; |
| 2687 | cexpr.var = readonly_id; |
| 2688 | } |
| 2689 | |
| 2690 | /* If we are not taking the address of the constraint expr, add all |
| 2691 | sub-fiels of the variable as well. */ |
| 2692 | if (!address_p) |
| 2693 | { |
| 2694 | for (; vi; vi = vi->next) |
| 2695 | { |
| 2696 | cexpr.var = vi->id; |
| 2697 | VEC_safe_push (ce_s, heap, *results, &cexpr); |
| 2698 | } |
| 2699 | return; |
| 2700 | } |
| 2701 | |
| 2702 | VEC_safe_push (ce_s, heap, *results, &cexpr); |
| 2703 | } |
| 2704 | |
| 2705 | /* Process constraint T, performing various simplifications and then |
| 2706 | adding it to our list of overall constraints. */ |
| 2707 | |
| 2708 | static void |
| 2709 | process_constraint (constraint_t t) |
| 2710 | { |
| 2711 | struct constraint_expr rhs = t->rhs; |
| 2712 | struct constraint_expr lhs = t->lhs; |
| 2713 | |
| 2714 | gcc_assert (rhs.var < VEC_length (varinfo_t, varmap)); |
| 2715 | gcc_assert (lhs.var < VEC_length (varinfo_t, varmap)); |
| 2716 | |
| 2717 | /* ANYTHING == ANYTHING is pointless. */ |
| 2718 | if (lhs.var == anything_id && rhs.var == anything_id) |
| 2719 | return; |
| 2720 | |
| 2721 | /* If we have &ANYTHING = something, convert to SOMETHING = &ANYTHING) */ |
| 2722 | else if (lhs.var == anything_id && lhs.type == ADDRESSOF) |
| 2723 | { |
| 2724 | rhs = t->lhs; |
| 2725 | t->lhs = t->rhs; |
| 2726 | t->rhs = rhs; |
| 2727 | process_constraint (t); |
| 2728 | } |
| 2729 | /* This can happen in our IR with things like n->a = *p */ |
| 2730 | else if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id) |
| 2731 | { |
| 2732 | /* Split into tmp = *rhs, *lhs = tmp */ |
| 2733 | tree rhsdecl = get_varinfo (rhs.var)->decl; |
| 2734 | tree pointertype = TREE_TYPE (rhsdecl); |
| 2735 | tree pointedtotype = TREE_TYPE (pointertype); |
| 2736 | tree tmpvar = create_tmp_var_raw (pointedtotype, "doubledereftmp"); |
| 2737 | struct constraint_expr tmplhs = get_constraint_exp_for_temp (tmpvar); |
| 2738 | |
| 2739 | process_constraint (new_constraint (tmplhs, rhs)); |
| 2740 | process_constraint (new_constraint (lhs, tmplhs)); |
| 2741 | } |
| 2742 | else if (rhs.type == ADDRESSOF && lhs.type == DEREF) |
| 2743 | { |
| 2744 | /* Split into tmp = &rhs, *lhs = tmp */ |
| 2745 | tree rhsdecl = get_varinfo (rhs.var)->decl; |
| 2746 | tree pointertype = TREE_TYPE (rhsdecl); |
| 2747 | tree tmpvar = create_tmp_var_raw (pointertype, "derefaddrtmp"); |
| 2748 | struct constraint_expr tmplhs = get_constraint_exp_for_temp (tmpvar); |
| 2749 | |
| 2750 | process_constraint (new_constraint (tmplhs, rhs)); |
| 2751 | process_constraint (new_constraint (lhs, tmplhs)); |
| 2752 | } |
| 2753 | else |
| 2754 | { |
| 2755 | gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0); |
| 2756 | VEC_safe_push (constraint_t, heap, constraints, t); |
| 2757 | } |
| 2758 | } |
| 2759 | |
| 2760 | /* Return true if T is a type that could contain pointers. */ |
| 2761 | |
| 2762 | static bool |
| 2763 | type_could_have_pointers (tree type) |
| 2764 | { |
| 2765 | if (POINTER_TYPE_P (type)) |
| 2766 | return true; |
| 2767 | |
| 2768 | if (TREE_CODE (type) == ARRAY_TYPE) |
| 2769 | return type_could_have_pointers (TREE_TYPE (type)); |
| 2770 | |
| 2771 | return AGGREGATE_TYPE_P (type); |
| 2772 | } |
| 2773 | |
| 2774 | /* Return true if T is a variable of a type that could contain |
| 2775 | pointers. */ |
| 2776 | |
| 2777 | static bool |
| 2778 | could_have_pointers (tree t) |
| 2779 | { |
| 2780 | return type_could_have_pointers (TREE_TYPE (t)); |
| 2781 | } |
| 2782 | |
| 2783 | /* Return the position, in bits, of FIELD_DECL from the beginning of its |
| 2784 | structure. */ |
| 2785 | |
| 2786 | static HOST_WIDE_INT |
| 2787 | bitpos_of_field (const tree fdecl) |
| 2788 | { |
| 2789 | |
| 2790 | if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0) |
| 2791 | || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0)) |
| 2792 | return -1; |
| 2793 | |
| 2794 | return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * 8 |
| 2795 | + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl))); |
| 2796 | } |
| 2797 | |
| 2798 | |
| 2799 | /* Get constraint expressions for offsetting PTR by OFFSET. Stores the |
| 2800 | resulting constraint expressions in *RESULTS. */ |
| 2801 | |
| 2802 | static void |
| 2803 | get_constraint_for_ptr_offset (tree ptr, tree offset, |
| 2804 | VEC (ce_s, heap) **results) |
| 2805 | { |
| 2806 | struct constraint_expr c; |
| 2807 | unsigned int j, n; |
| 2808 | unsigned HOST_WIDE_INT rhsunitoffset, rhsoffset; |
| 2809 | |
| 2810 | /* If we do not do field-sensitive PTA adding offsets to pointers |
| 2811 | does not change the points-to solution. */ |
| 2812 | if (!use_field_sensitive) |
| 2813 | { |
| 2814 | get_constraint_for (ptr, results); |
| 2815 | return; |
| 2816 | } |
| 2817 | |
| 2818 | /* If the offset is not a non-negative integer constant that fits |
| 2819 | in a HOST_WIDE_INT, we have to fall back to a conservative |
| 2820 | solution which includes all sub-fields of all pointed-to |
| 2821 | variables of ptr. |
| 2822 | ??? As we do not have the ability to express this, fall back |
| 2823 | to anything. */ |
| 2824 | if (!host_integerp (offset, 1)) |
| 2825 | { |
| 2826 | struct constraint_expr temp; |
| 2827 | temp.var = anything_id; |
| 2828 | temp.type = SCALAR; |
| 2829 | temp.offset = 0; |
| 2830 | VEC_safe_push (ce_s, heap, *results, &temp); |
| 2831 | return; |
| 2832 | } |
| 2833 | |
| 2834 | /* Make sure the bit-offset also fits. */ |
| 2835 | rhsunitoffset = TREE_INT_CST_LOW (offset); |
| 2836 | rhsoffset = rhsunitoffset * BITS_PER_UNIT; |
| 2837 | if (rhsunitoffset != rhsoffset / BITS_PER_UNIT) |
| 2838 | { |
| 2839 | struct constraint_expr temp; |
| 2840 | temp.var = anything_id; |
| 2841 | temp.type = SCALAR; |
| 2842 | temp.offset = 0; |
| 2843 | VEC_safe_push (ce_s, heap, *results, &temp); |
| 2844 | return; |
| 2845 | } |
| 2846 | |
| 2847 | get_constraint_for (ptr, results); |
| 2848 | if (rhsoffset == 0) |
| 2849 | return; |
| 2850 | |
| 2851 | /* As we are eventually appending to the solution do not use |
| 2852 | VEC_iterate here. */ |
| 2853 | n = VEC_length (ce_s, *results); |
| 2854 | for (j = 0; j < n; j++) |
| 2855 | { |
| 2856 | varinfo_t curr; |
| 2857 | c = *VEC_index (ce_s, *results, j); |
| 2858 | curr = get_varinfo (c.var); |
| 2859 | |
| 2860 | if (c.type == ADDRESSOF |
| 2861 | && !curr->is_full_var) |
| 2862 | { |
| 2863 | varinfo_t temp, curr = get_varinfo (c.var); |
| 2864 | |
| 2865 | /* Search the sub-field which overlaps with the |
| 2866 | pointed-to offset. As we deal with positive offsets |
| 2867 | only, we can start the search from the current variable. */ |
| 2868 | temp = first_vi_for_offset (curr, curr->offset + rhsoffset); |
| 2869 | |
| 2870 | /* If the result is outside of the variable we have to provide |
| 2871 | a conservative result, as the variable is still reachable |
| 2872 | from the resulting pointer (even though it technically |
| 2873 | cannot point to anything). The last sub-field is such |
| 2874 | a conservative result. |
| 2875 | ??? If we always had a sub-field for &object + 1 then |
| 2876 | we could represent this in a more precise way. */ |
| 2877 | if (temp == NULL) |
| 2878 | { |
| 2879 | temp = curr; |
| 2880 | while (temp->next != NULL) |
| 2881 | temp = temp->next; |
| 2882 | continue; |
| 2883 | } |
| 2884 | |
| 2885 | /* If the found variable is not exactly at the pointed to |
| 2886 | result, we have to include the next variable in the |
| 2887 | solution as well. Otherwise two increments by offset / 2 |
| 2888 | do not result in the same or a conservative superset |
| 2889 | solution. */ |
| 2890 | if (temp->offset != curr->offset + rhsoffset |
| 2891 | && temp->next != NULL) |
| 2892 | { |
| 2893 | struct constraint_expr c2; |
| 2894 | c2.var = temp->next->id; |
| 2895 | c2.type = ADDRESSOF; |
| 2896 | c2.offset = 0; |
| 2897 | VEC_safe_push (ce_s, heap, *results, &c2); |
| 2898 | } |
| 2899 | c.var = temp->id; |
| 2900 | c.offset = 0; |
| 2901 | } |
| 2902 | else if (c.type == ADDRESSOF |
| 2903 | /* If this varinfo represents a full variable just use it. */ |
| 2904 | && curr->is_full_var) |
| 2905 | c.offset = 0; |
| 2906 | else |
| 2907 | c.offset = rhsoffset; |
| 2908 | |
| 2909 | VEC_replace (ce_s, *results, j, &c); |
| 2910 | } |
| 2911 | } |
| 2912 | |
| 2913 | |
| 2914 | /* Given a COMPONENT_REF T, return the constraint_expr vector for it. |
| 2915 | If address_p is true the result will be taken its address of. */ |
| 2916 | |
| 2917 | static void |
| 2918 | get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results, |
| 2919 | bool address_p) |
| 2920 | { |
| 2921 | tree orig_t = t; |
| 2922 | HOST_WIDE_INT bitsize = -1; |
| 2923 | HOST_WIDE_INT bitmaxsize = -1; |
| 2924 | HOST_WIDE_INT bitpos; |
| 2925 | tree forzero; |
| 2926 | struct constraint_expr *result; |
| 2927 | |
| 2928 | /* Some people like to do cute things like take the address of |
| 2929 | &0->a.b */ |
| 2930 | forzero = t; |
| 2931 | while (handled_component_p (forzero) |
| 2932 | || INDIRECT_REF_P (forzero)) |
| 2933 | forzero = TREE_OPERAND (forzero, 0); |
| 2934 | |
| 2935 | if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero)) |
| 2936 | { |
| 2937 | struct constraint_expr temp; |
| 2938 | |
| 2939 | temp.offset = 0; |
| 2940 | temp.var = integer_id; |
| 2941 | temp.type = SCALAR; |
| 2942 | VEC_safe_push (ce_s, heap, *results, &temp); |
| 2943 | return; |
| 2944 | } |
| 2945 | |
| 2946 | t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize); |
| 2947 | |
| 2948 | /* Pretend to take the address of the base, we'll take care of |
| 2949 | adding the required subset of sub-fields below. */ |
| 2950 | get_constraint_for_1 (t, results, true); |
| 2951 | gcc_assert (VEC_length (ce_s, *results) == 1); |
| 2952 | result = VEC_last (ce_s, *results); |
| 2953 | |
| 2954 | /* This can also happen due to weird offsetof type macros. */ |
| 2955 | if (TREE_CODE (t) != ADDR_EXPR && result->type == ADDRESSOF) |
| 2956 | result->type = SCALAR; |
| 2957 | |
| 2958 | if (result->type == SCALAR |
| 2959 | && get_varinfo (result->var)->is_full_var) |
| 2960 | /* For single-field vars do not bother about the offset. */ |
| 2961 | result->offset = 0; |
| 2962 | else if (result->type == SCALAR) |
| 2963 | { |
| 2964 | /* In languages like C, you can access one past the end of an |
| 2965 | array. You aren't allowed to dereference it, so we can |
| 2966 | ignore this constraint. When we handle pointer subtraction, |
| 2967 | we may have to do something cute here. */ |
| 2968 | |
| 2969 | if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize |
| 2970 | && bitmaxsize != 0) |
| 2971 | { |
| 2972 | /* It's also not true that the constraint will actually start at the |
| 2973 | right offset, it may start in some padding. We only care about |
| 2974 | setting the constraint to the first actual field it touches, so |
| 2975 | walk to find it. */ |
| 2976 | struct constraint_expr cexpr = *result; |
| 2977 | varinfo_t curr; |
| 2978 | VEC_pop (ce_s, *results); |
| 2979 | cexpr.offset = 0; |
| 2980 | for (curr = get_varinfo (cexpr.var); curr; curr = curr->next) |
| 2981 | { |
| 2982 | if (ranges_overlap_p (curr->offset, curr->size, |
| 2983 | bitpos, bitmaxsize)) |
| 2984 | { |
| 2985 | cexpr.var = curr->id; |
| 2986 | VEC_safe_push (ce_s, heap, *results, &cexpr); |
| 2987 | if (address_p) |
| 2988 | break; |
| 2989 | } |
| 2990 | } |
| 2991 | /* If we are going to take the address of this field then |
| 2992 | to be able to compute reachability correctly add at least |
| 2993 | the last field of the variable. */ |
| 2994 | if (address_p |
| 2995 | && VEC_length (ce_s, *results) == 0) |
| 2996 | { |
| 2997 | curr = get_varinfo (cexpr.var); |
| 2998 | while (curr->next != NULL) |
| 2999 | curr = curr->next; |
| 3000 | cexpr.var = curr->id; |
| 3001 | VEC_safe_push (ce_s, heap, *results, &cexpr); |
| 3002 | } |
| 3003 | else |
| 3004 | /* Assert that we found *some* field there. The user couldn't be |
| 3005 | accessing *only* padding. */ |
| 3006 | /* Still the user could access one past the end of an array |
| 3007 | embedded in a struct resulting in accessing *only* padding. */ |
| 3008 | gcc_assert (VEC_length (ce_s, *results) >= 1 |
| 3009 | || ref_contains_array_ref (orig_t)); |
| 3010 | } |
| 3011 | else if (bitmaxsize == 0) |
| 3012 | { |
| 3013 | if (dump_file && (dump_flags & TDF_DETAILS)) |
| 3014 | fprintf (dump_file, "Access to zero-sized part of variable," |
| 3015 | "ignoring\n"); |
| 3016 | } |
| 3017 | else |
| 3018 | if (dump_file && (dump_flags & TDF_DETAILS)) |
| 3019 | fprintf (dump_file, "Access to past the end of variable, ignoring\n"); |
| 3020 | } |
| 3021 | else if (bitmaxsize == -1) |
| 3022 | { |
| 3023 | /* We can't handle DEREF constraints with unknown size, we'll |
| 3024 | get the wrong answer. Punt and return anything. */ |
| 3025 | result->var = anything_id; |
| 3026 | result->offset = 0; |
| 3027 | } |
| 3028 | else |
| 3029 | result->offset = bitpos; |
| 3030 | } |
| 3031 | |
| 3032 | |
| 3033 | /* Dereference the constraint expression CONS, and return the result. |
| 3034 | DEREF (ADDRESSOF) = SCALAR |
| 3035 | DEREF (SCALAR) = DEREF |
| 3036 | DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp)) |
| 3037 | This is needed so that we can handle dereferencing DEREF constraints. */ |
| 3038 | |
| 3039 | static void |
| 3040 | do_deref (VEC (ce_s, heap) **constraints) |
| 3041 | { |
| 3042 | struct constraint_expr *c; |
| 3043 | unsigned int i = 0; |
| 3044 | |
| 3045 | for (i = 0; VEC_iterate (ce_s, *constraints, i, c); i++) |
| 3046 | { |
| 3047 | if (c->type == SCALAR) |
| 3048 | c->type = DEREF; |
| 3049 | else if (c->type == ADDRESSOF) |
| 3050 | c->type = SCALAR; |
| 3051 | else if (c->type == DEREF) |
| 3052 | { |
| 3053 | tree tmpvar = create_tmp_var_raw (ptr_type_node, "dereftmp"); |
| 3054 | struct constraint_expr tmplhs = get_constraint_exp_for_temp (tmpvar); |
| 3055 | process_constraint (new_constraint (tmplhs, *c)); |
| 3056 | c->var = tmplhs.var; |
| 3057 | } |
| 3058 | else |
| 3059 | gcc_unreachable (); |
| 3060 | } |
| 3061 | } |
| 3062 | |
| 3063 | /* Given a tree T, return the constraint expression for it. */ |
| 3064 | |
| 3065 | static void |
| 3066 | get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p) |
| 3067 | { |
| 3068 | struct constraint_expr temp; |
| 3069 | |
| 3070 | /* x = integer is all glommed to a single variable, which doesn't |
| 3071 | point to anything by itself. That is, of course, unless it is an |
| 3072 | integer constant being treated as a pointer, in which case, we |
| 3073 | will return that this is really the addressof anything. This |
| 3074 | happens below, since it will fall into the default case. The only |
| 3075 | case we know something about an integer treated like a pointer is |
| 3076 | when it is the NULL pointer, and then we just say it points to |
| 3077 | NULL. |
| 3078 | |
| 3079 | Do not do that if -fno-delete-null-pointer-checks though, because |
| 3080 | in that case *NULL does not fail, so it _should_ alias *anything. |
| 3081 | It is not worth adding a new option or renaming the existing one, |
| 3082 | since this case is relatively obscure. */ |
| 3083 | if (flag_delete_null_pointer_checks |
| 3084 | && TREE_CODE (t) == INTEGER_CST |
| 3085 | && integer_zerop (t)) |
| 3086 | { |
| 3087 | temp.var = nothing_id; |
| 3088 | temp.type = ADDRESSOF; |
| 3089 | temp.offset = 0; |
| 3090 | VEC_safe_push (ce_s, heap, *results, &temp); |
| 3091 | return; |
| 3092 | } |
| 3093 | |
| 3094 | /* String constants are read-only. */ |
| 3095 | if (TREE_CODE (t) == STRING_CST) |
| 3096 | { |
| 3097 | temp.var = readonly_id; |
| 3098 | temp.type = SCALAR; |
| 3099 | temp.offset = 0; |
| 3100 | VEC_safe_push (ce_s, heap, *results, &temp); |
| 3101 | return; |
| 3102 | } |
| 3103 | |
| 3104 | switch (TREE_CODE_CLASS (TREE_CODE (t))) |
| 3105 | { |
| 3106 | case tcc_expression: |
| 3107 | { |
| 3108 | switch (TREE_CODE (t)) |
| 3109 | { |
| 3110 | case ADDR_EXPR: |
| 3111 | { |
| 3112 | struct constraint_expr *c; |
| 3113 | unsigned int i; |
| 3114 | tree exp = TREE_OPERAND (t, 0); |
| 3115 | |
| 3116 | get_constraint_for_1 (exp, results, true); |
| 3117 | |
| 3118 | for (i = 0; VEC_iterate (ce_s, *results, i, c); i++) |
| 3119 | { |
| 3120 | if (c->type == DEREF) |
| 3121 | c->type = SCALAR; |
| 3122 | else |
| 3123 | c->type = ADDRESSOF; |
| 3124 | } |
| 3125 | return; |
| 3126 | } |
| 3127 | break; |
| 3128 | default:; |
| 3129 | } |
| 3130 | break; |
| 3131 | } |
| 3132 | case tcc_reference: |
| 3133 | { |
| 3134 | switch (TREE_CODE (t)) |
| 3135 | { |
| 3136 | case INDIRECT_REF: |
| 3137 | { |
| 3138 | get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p); |
| 3139 | do_deref (results); |
| 3140 | return; |
| 3141 | } |
| 3142 | case ARRAY_REF: |
| 3143 | case ARRAY_RANGE_REF: |
| 3144 | case COMPONENT_REF: |
| 3145 | get_constraint_for_component_ref (t, results, address_p); |
| 3146 | return; |
| 3147 | default:; |
| 3148 | } |
| 3149 | break; |
| 3150 | } |
| 3151 | case tcc_exceptional: |
| 3152 | { |
| 3153 | switch (TREE_CODE (t)) |
| 3154 | { |
| 3155 | case SSA_NAME: |
| 3156 | { |
| 3157 | get_constraint_for_ssa_var (t, results, address_p); |
| 3158 | return; |
| 3159 | } |
| 3160 | default:; |
| 3161 | } |
| 3162 | break; |
| 3163 | } |
| 3164 | case tcc_declaration: |
| 3165 | { |
| 3166 | get_constraint_for_ssa_var (t, results, address_p); |
| 3167 | return; |
| 3168 | } |
| 3169 | default:; |
| 3170 | } |
| 3171 | |
| 3172 | /* The default fallback is a constraint from anything. */ |
| 3173 | temp.type = ADDRESSOF; |
| 3174 | temp.var = anything_id; |
| 3175 | temp.offset = 0; |
| 3176 | VEC_safe_push (ce_s, heap, *results, &temp); |
| 3177 | } |
| 3178 | |
| 3179 | /* Given a gimple tree T, return the constraint expression vector for it. */ |
| 3180 | |
| 3181 | static void |
| 3182 | get_constraint_for (tree t, VEC (ce_s, heap) **results) |
| 3183 | { |
| 3184 | gcc_assert (VEC_length (ce_s, *results) == 0); |
| 3185 | |
| 3186 | get_constraint_for_1 (t, results, false); |
| 3187 | } |
| 3188 | |
| 3189 | /* Handle the structure copy case where we have a simple structure copy |
| 3190 | between LHS and RHS that is of SIZE (in bits) |
| 3191 | |
| 3192 | For each field of the lhs variable (lhsfield) |
| 3193 | For each field of the rhs variable at lhsfield.offset (rhsfield) |
| 3194 | add the constraint lhsfield = rhsfield |
| 3195 | |
| 3196 | If we fail due to some kind of type unsafety or other thing we |
| 3197 | can't handle, return false. We expect the caller to collapse the |
| 3198 | variable in that case. */ |
| 3199 | |
| 3200 | static bool |
| 3201 | do_simple_structure_copy (const struct constraint_expr lhs, |
| 3202 | const struct constraint_expr rhs, |
| 3203 | const unsigned HOST_WIDE_INT size) |
| 3204 | { |
| 3205 | varinfo_t p = get_varinfo (lhs.var); |
| 3206 | unsigned HOST_WIDE_INT pstart, last; |
| 3207 | pstart = p->offset; |
| 3208 | last = p->offset + size; |
| 3209 | for (; p && p->offset < last; p = p->next) |
| 3210 | { |
| 3211 | varinfo_t q; |
| 3212 | struct constraint_expr templhs = lhs; |
| 3213 | struct constraint_expr temprhs = rhs; |
| 3214 | unsigned HOST_WIDE_INT fieldoffset; |
| 3215 | |
| 3216 | templhs.var = p->id; |
| 3217 | q = get_varinfo (temprhs.var); |
| 3218 | fieldoffset = p->offset - pstart; |
| 3219 | q = first_vi_for_offset (q, q->offset + fieldoffset); |
| 3220 | if (!q) |
| 3221 | return false; |
| 3222 | temprhs.var = q->id; |
| 3223 | process_constraint (new_constraint (templhs, temprhs)); |
| 3224 | } |
| 3225 | return true; |
| 3226 | } |
| 3227 | |
| 3228 | |
| 3229 | /* Handle the structure copy case where we have a structure copy between a |
| 3230 | aggregate on the LHS and a dereference of a pointer on the RHS |
| 3231 | that is of SIZE (in bits) |
| 3232 | |
| 3233 | For each field of the lhs variable (lhsfield) |
| 3234 | rhs.offset = lhsfield->offset |
| 3235 | add the constraint lhsfield = rhs |
| 3236 | */ |
| 3237 | |
| 3238 | static void |
| 3239 | do_rhs_deref_structure_copy (const struct constraint_expr lhs, |
| 3240 | const struct constraint_expr rhs, |
| 3241 | const unsigned HOST_WIDE_INT size) |
| 3242 | { |
| 3243 | varinfo_t p = get_varinfo (lhs.var); |
| 3244 | unsigned HOST_WIDE_INT pstart,last; |
| 3245 | pstart = p->offset; |
| 3246 | last = p->offset + size; |
| 3247 | |
| 3248 | for (; p && p->offset < last; p = p->next) |
| 3249 | { |
| 3250 | varinfo_t q; |
| 3251 | struct constraint_expr templhs = lhs; |
| 3252 | struct constraint_expr temprhs = rhs; |
| 3253 | unsigned HOST_WIDE_INT fieldoffset; |
| 3254 | |
| 3255 | |
| 3256 | if (templhs.type == SCALAR) |
| 3257 | templhs.var = p->id; |
| 3258 | else |
| 3259 | templhs.offset = p->offset; |
| 3260 | |
| 3261 | q = get_varinfo (temprhs.var); |
| 3262 | fieldoffset = p->offset - pstart; |
| 3263 | temprhs.offset += fieldoffset; |
| 3264 | process_constraint (new_constraint (templhs, temprhs)); |
| 3265 | } |
| 3266 | } |
| 3267 | |
| 3268 | /* Handle the structure copy case where we have a structure copy |
| 3269 | between an aggregate on the RHS and a dereference of a pointer on |
| 3270 | the LHS that is of SIZE (in bits) |
| 3271 | |
| 3272 | For each field of the rhs variable (rhsfield) |
| 3273 | lhs.offset = rhsfield->offset |
| 3274 | add the constraint lhs = rhsfield |
| 3275 | */ |
| 3276 | |
| 3277 | static void |
| 3278 | do_lhs_deref_structure_copy (const struct constraint_expr lhs, |
| 3279 | const struct constraint_expr rhs, |
| 3280 | const unsigned HOST_WIDE_INT size) |
| 3281 | { |
| 3282 | varinfo_t p = get_varinfo (rhs.var); |
| 3283 | unsigned HOST_WIDE_INT pstart,last; |
| 3284 | pstart = p->offset; |
| 3285 | last = p->offset + size; |
| 3286 | |
| 3287 | for (; p && p->offset < last; p = p->next) |
| 3288 | { |
| 3289 | varinfo_t q; |
| 3290 | struct constraint_expr templhs = lhs; |
| 3291 | struct constraint_expr temprhs = rhs; |
| 3292 | unsigned HOST_WIDE_INT fieldoffset; |
| 3293 | |
| 3294 | |
| 3295 | if (temprhs.type == SCALAR) |
| 3296 | temprhs.var = p->id; |
| 3297 | else |
| 3298 | temprhs.offset = p->offset; |
| 3299 | |
| 3300 | q = get_varinfo (templhs.var); |
| 3301 | fieldoffset = p->offset - pstart; |
| 3302 | templhs.offset += fieldoffset; |
| 3303 | process_constraint (new_constraint (templhs, temprhs)); |
| 3304 | } |
| 3305 | } |
| 3306 | |
| 3307 | /* Sometimes, frontends like to give us bad type information. This |
| 3308 | function will collapse all the fields from VAR to the end of VAR, |
| 3309 | into VAR, so that we treat those fields as a single variable. |
| 3310 | We return the variable they were collapsed into. */ |
| 3311 | |
| 3312 | static unsigned int |
| 3313 | collapse_rest_of_var (unsigned int var) |
| 3314 | { |
| 3315 | varinfo_t currvar = get_varinfo (var); |
| 3316 | varinfo_t field; |
| 3317 | |
| 3318 | for (field = currvar->next; field; field = field->next) |
| 3319 | { |
| 3320 | if (dump_file) |
| 3321 | fprintf (dump_file, "Type safety: Collapsing var %s into %s\n", |
| 3322 | field->name, currvar->name); |
| 3323 | |
| 3324 | gcc_assert (field->collapsed_to == 0); |
| 3325 | field->collapsed_to = currvar->id; |
| 3326 | } |
| 3327 | |
| 3328 | currvar->next = NULL; |
| 3329 | currvar->size = currvar->fullsize - currvar->offset; |
| 3330 | |
| 3331 | return currvar->id; |
| 3332 | } |
| 3333 | |
| 3334 | /* Handle aggregate copies by expanding into copies of the respective |
| 3335 | fields of the structures. */ |
| 3336 | |
| 3337 | static void |
| 3338 | do_structure_copy (tree lhsop, tree rhsop) |
| 3339 | { |
| 3340 | struct constraint_expr lhs, rhs, tmp; |
| 3341 | VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL; |
| 3342 | varinfo_t p; |
| 3343 | unsigned HOST_WIDE_INT lhssize; |
| 3344 | unsigned HOST_WIDE_INT rhssize; |
| 3345 | |
| 3346 | /* Pretend we are taking the address of the constraint exprs. |
| 3347 | We deal with walking the sub-fields ourselves. */ |
| 3348 | get_constraint_for_1 (lhsop, &lhsc, true); |
| 3349 | get_constraint_for_1 (rhsop, &rhsc, true); |
| 3350 | gcc_assert (VEC_length (ce_s, lhsc) == 1); |
| 3351 | gcc_assert (VEC_length (ce_s, rhsc) == 1); |
| 3352 | lhs = *(VEC_last (ce_s, lhsc)); |
| 3353 | rhs = *(VEC_last (ce_s, rhsc)); |
| 3354 | |
| 3355 | VEC_free (ce_s, heap, lhsc); |
| 3356 | VEC_free (ce_s, heap, rhsc); |
| 3357 | |
| 3358 | /* If we have special var = x, swap it around. */ |
| 3359 | if (lhs.var <= integer_id && !(get_varinfo (rhs.var)->is_special_var)) |
| 3360 | { |
| 3361 | tmp = lhs; |
| 3362 | lhs = rhs; |
| 3363 | rhs = tmp; |
| 3364 | } |
| 3365 | |
| 3366 | /* This is fairly conservative for the RHS == ADDRESSOF case, in that it's |
| 3367 | possible it's something we could handle. However, most cases falling |
| 3368 | into this are dealing with transparent unions, which are slightly |
| 3369 | weird. */ |
| 3370 | if (rhs.type == ADDRESSOF && !(get_varinfo (rhs.var)->is_special_var)) |
| 3371 | { |
| 3372 | rhs.type = ADDRESSOF; |
| 3373 | rhs.var = anything_id; |
| 3374 | } |
| 3375 | |
| 3376 | /* If the RHS is a special var, or an addressof, set all the LHS fields to |
| 3377 | that special var. */ |
| 3378 | if (rhs.var <= integer_id) |
| 3379 | { |
| 3380 | for (p = get_varinfo (lhs.var); p; p = p->next) |
| 3381 | { |
| 3382 | struct constraint_expr templhs = lhs; |
| 3383 | struct constraint_expr temprhs = rhs; |
| 3384 | |
| 3385 | if (templhs.type == SCALAR ) |
| 3386 | templhs.var = p->id; |
| 3387 | else |
| 3388 | templhs.offset += p->offset; |
| 3389 | process_constraint (new_constraint (templhs, temprhs)); |
| 3390 | } |
| 3391 | } |
| 3392 | else |
| 3393 | { |
| 3394 | tree rhstype = TREE_TYPE (rhsop); |
| 3395 | tree lhstype = TREE_TYPE (lhsop); |
| 3396 | tree rhstypesize; |
| 3397 | tree lhstypesize; |
| 3398 | |
| 3399 | lhstypesize = DECL_P (lhsop) ? DECL_SIZE (lhsop) : TYPE_SIZE (lhstype); |
| 3400 | rhstypesize = DECL_P (rhsop) ? DECL_SIZE (rhsop) : TYPE_SIZE (rhstype); |
| 3401 | |
| 3402 | /* If we have a variably sized types on the rhs or lhs, and a deref |
| 3403 | constraint, add the constraint, lhsconstraint = &ANYTHING. |
| 3404 | This is conservatively correct because either the lhs is an unknown |
| 3405 | sized var (if the constraint is SCALAR), or the lhs is a DEREF |
| 3406 | constraint, and every variable it can point to must be unknown sized |
| 3407 | anyway, so we don't need to worry about fields at all. */ |
| 3408 | if ((rhs.type == DEREF && TREE_CODE (rhstypesize) != INTEGER_CST) |
| 3409 | || (lhs.type == DEREF && TREE_CODE (lhstypesize) != INTEGER_CST)) |
| 3410 | { |
| 3411 | rhs.var = anything_id; |
| 3412 | rhs.type = ADDRESSOF; |
| 3413 | rhs.offset = 0; |
| 3414 | process_constraint (new_constraint (lhs, rhs)); |
| 3415 | return; |
| 3416 | } |
| 3417 | |
| 3418 | /* The size only really matters insofar as we don't set more or less of |
| 3419 | the variable. If we hit an unknown size var, the size should be the |
| 3420 | whole darn thing. */ |
| 3421 | if (get_varinfo (rhs.var)->is_unknown_size_var) |
| 3422 | rhssize = ~0; |
| 3423 | else |
| 3424 | rhssize = TREE_INT_CST_LOW (rhstypesize); |
| 3425 | |
| 3426 | if (get_varinfo (lhs.var)->is_unknown_size_var) |
| 3427 | lhssize = ~0; |
| 3428 | else |
| 3429 | lhssize = TREE_INT_CST_LOW (lhstypesize); |
| 3430 | |
| 3431 | |
| 3432 | if (rhs.type == SCALAR && lhs.type == SCALAR) |
| 3433 | { |
| 3434 | if (!do_simple_structure_copy (lhs, rhs, MIN (lhssize, rhssize))) |
| 3435 | { |
| 3436 | lhs.var = collapse_rest_of_var (get_varinfo_fc (lhs.var)->id); |
| 3437 | rhs.var = collapse_rest_of_var (get_varinfo_fc (rhs.var)->id); |
| 3438 | lhs.offset = 0; |
| 3439 | rhs.offset = 0; |
| 3440 | lhs.type = SCALAR; |
| 3441 | rhs.type = SCALAR; |
| 3442 | process_constraint (new_constraint (lhs, rhs)); |
| 3443 | } |
| 3444 | } |
| 3445 | else if (lhs.type != DEREF && rhs.type == DEREF) |
| 3446 | do_rhs_deref_structure_copy (lhs, rhs, MIN (lhssize, rhssize)); |
| 3447 | else if (lhs.type == DEREF && rhs.type != DEREF) |
| 3448 | do_lhs_deref_structure_copy (lhs, rhs, MIN (lhssize, rhssize)); |
| 3449 | else |
| 3450 | { |
| 3451 | tree pointedtotype = lhstype; |
| 3452 | tree tmpvar; |
| 3453 | |
| 3454 | gcc_assert (rhs.type == DEREF && lhs.type == DEREF); |
| 3455 | tmpvar = create_tmp_var_raw (pointedtotype, "structcopydereftmp"); |
| 3456 | do_structure_copy (tmpvar, rhsop); |
| 3457 | do_structure_copy (lhsop, tmpvar); |
| 3458 | } |
| 3459 | } |
| 3460 | } |
| 3461 | |
| 3462 | /* Create a constraint ID = OP. */ |
| 3463 | |
| 3464 | static void |
| 3465 | make_constraint_to (unsigned id, tree op) |
| 3466 | { |
| 3467 | VEC(ce_s, heap) *rhsc = NULL; |
| 3468 | struct constraint_expr *c; |
| 3469 | struct constraint_expr includes; |
| 3470 | unsigned int j; |
| 3471 | |
| 3472 | includes.var = id; |
| 3473 | includes.offset = 0; |
| 3474 | includes.type = SCALAR; |
| 3475 | |
| 3476 | get_constraint_for (op, &rhsc); |
| 3477 | for (j = 0; VEC_iterate (ce_s, rhsc, j, c); j++) |
| 3478 | process_constraint (new_constraint (includes, *c)); |
| 3479 | VEC_free (ce_s, heap, rhsc); |
| 3480 | } |
| 3481 | |
| 3482 | /* Make constraints necessary to make OP escape. */ |
| 3483 | |
| 3484 | static void |
| 3485 | make_escape_constraint (tree op) |
| 3486 | { |
| 3487 | make_constraint_to (escaped_id, op); |
| 3488 | } |
| 3489 | |
| 3490 | /* For non-IPA mode, generate constraints necessary for a call on the |
| 3491 | RHS. */ |
| 3492 | |
| 3493 | static void |
| 3494 | handle_rhs_call (gimple stmt) |
| 3495 | { |
| 3496 | unsigned i; |
| 3497 | |
| 3498 | for (i = 0; i < gimple_call_num_args (stmt); ++i) |
| 3499 | { |
| 3500 | tree arg = gimple_call_arg (stmt, i); |
| 3501 | |
| 3502 | /* Find those pointers being passed, and make sure they end up |
| 3503 | pointing to anything. */ |
| 3504 | if (could_have_pointers (arg)) |
| 3505 | make_escape_constraint (arg); |
| 3506 | } |
| 3507 | |
| 3508 | /* The static chain escapes as well. */ |
| 3509 | if (gimple_call_chain (stmt)) |
| 3510 | make_escape_constraint (gimple_call_chain (stmt)); |
| 3511 | } |
| 3512 | |
| 3513 | /* For non-IPA mode, generate constraints necessary for a call |
| 3514 | that returns a pointer and assigns it to LHS. This simply makes |
| 3515 | the LHS point to global and escaped variables. */ |
| 3516 | |
| 3517 | static void |
| 3518 | handle_lhs_call (tree lhs, int flags) |
| 3519 | { |
| 3520 | VEC(ce_s, heap) *lhsc = NULL; |
| 3521 | struct constraint_expr rhsc; |
| 3522 | unsigned int j; |
| 3523 | struct constraint_expr *lhsp; |
| 3524 | |
| 3525 | get_constraint_for (lhs, &lhsc); |
| 3526 | |
| 3527 | if (flags & ECF_MALLOC) |
| 3528 | { |
| 3529 | tree heapvar = heapvar_lookup (lhs); |
| 3530 | varinfo_t vi; |
| 3531 | |
| 3532 | if (heapvar == NULL) |
| 3533 | { |
| 3534 | heapvar = create_tmp_var_raw (ptr_type_node, "HEAP"); |
| 3535 | DECL_EXTERNAL (heapvar) = 1; |
| 3536 | get_var_ann (heapvar)->is_heapvar = 1; |
| 3537 | if (gimple_referenced_vars (cfun)) |
| 3538 | add_referenced_var (heapvar); |
| 3539 | heapvar_insert (lhs, heapvar); |
| 3540 | } |
| 3541 | |
| 3542 | rhsc.var = create_variable_info_for (heapvar, |
| 3543 | alias_get_name (heapvar)); |
| 3544 | vi = get_varinfo (rhsc.var); |
| 3545 | vi->is_artificial_var = 1; |
| 3546 | vi->is_heap_var = 1; |
| 3547 | vi->is_unknown_size_var = true; |
| 3548 | vi->fullsize = ~0; |
| 3549 | vi->size = ~0; |
| 3550 | rhsc.type = ADDRESSOF; |
| 3551 | rhsc.offset = 0; |
| 3552 | } |
| 3553 | else |
| 3554 | { |
| 3555 | rhsc.var = escaped_id; |
| 3556 | rhsc.offset = 0; |
| 3557 | rhsc.type = ADDRESSOF; |
| 3558 | } |
| 3559 | for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++) |
| 3560 | process_constraint (new_constraint (*lhsp, rhsc)); |
| 3561 | VEC_free (ce_s, heap, lhsc); |
| 3562 | } |
| 3563 | |
| 3564 | /* For non-IPA mode, generate constraints necessary for a call of a |
| 3565 | const function that returns a pointer in the statement STMT. */ |
| 3566 | |
| 3567 | static void |
| 3568 | handle_const_call (gimple stmt) |
| 3569 | { |
| 3570 | tree lhs = gimple_call_lhs (stmt); |
| 3571 | VEC(ce_s, heap) *lhsc = NULL; |
| 3572 | struct constraint_expr rhsc; |
| 3573 | unsigned int j, k; |
| 3574 | struct constraint_expr *lhsp; |
| 3575 | tree tmpvar; |
| 3576 | struct constraint_expr tmpc; |
| 3577 | |
| 3578 | get_constraint_for (lhs, &lhsc); |
| 3579 | |
| 3580 | /* If this is a nested function then it can return anything. */ |
| 3581 | if (gimple_call_chain (stmt)) |
| 3582 | { |
| 3583 | rhsc.var = anything_id; |
| 3584 | rhsc.offset = 0; |
| 3585 | rhsc.type = ADDRESSOF; |
| 3586 | for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++) |
| 3587 | process_constraint (new_constraint (*lhsp, rhsc)); |
| 3588 | VEC_free (ce_s, heap, lhsc); |
| 3589 | return; |
| 3590 | } |
| 3591 | |
| 3592 | /* We always use a temporary here, otherwise we end up with a quadratic |
| 3593 | amount of constraints for |
| 3594 | large_struct = const_call (large_struct); |
| 3595 | in field-sensitive PTA. */ |
| 3596 | tmpvar = create_tmp_var_raw (ptr_type_node, "consttmp"); |
| 3597 | tmpc = get_constraint_exp_for_temp (tmpvar); |
| 3598 | |
| 3599 | /* May return addresses of globals. */ |
| 3600 | rhsc.var = nonlocal_id; |
| 3601 | rhsc.offset = 0; |
| 3602 | rhsc.type = ADDRESSOF; |
| 3603 | process_constraint (new_constraint (tmpc, rhsc)); |
| 3604 | |
| 3605 | /* May return arguments. */ |
| 3606 | for (k = 0; k < gimple_call_num_args (stmt); ++k) |
| 3607 | { |
| 3608 | tree arg = gimple_call_arg (stmt, k); |
| 3609 | |
| 3610 | if (could_have_pointers (arg)) |
| 3611 | { |
| 3612 | VEC(ce_s, heap) *argc = NULL; |
| 3613 | struct constraint_expr *argp; |
| 3614 | int i; |
| 3615 | |
| 3616 | get_constraint_for (arg, &argc); |
| 3617 | for (i = 0; VEC_iterate (ce_s, argc, i, argp); i++) |
| 3618 | process_constraint (new_constraint (tmpc, *argp)); |
| 3619 | VEC_free (ce_s, heap, argc); |
| 3620 | } |
| 3621 | } |
| 3622 | |
| 3623 | for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++) |
| 3624 | process_constraint (new_constraint (*lhsp, tmpc)); |
| 3625 | |
| 3626 | VEC_free (ce_s, heap, lhsc); |
| 3627 | } |
| 3628 | |
| 3629 | /* For non-IPA mode, generate constraints necessary for a call to a |
| 3630 | pure function in statement STMT. */ |
| 3631 | |
| 3632 | static void |
| 3633 | handle_pure_call (gimple stmt) |
| 3634 | { |
| 3635 | unsigned i; |
| 3636 | |
| 3637 | /* Memory reached from pointer arguments is call-used. */ |
| 3638 | for (i = 0; i < gimple_call_num_args (stmt); ++i) |
| 3639 | { |
| 3640 | tree arg = gimple_call_arg (stmt, i); |
| 3641 | |
| 3642 | if (could_have_pointers (arg)) |
| 3643 | make_constraint_to (callused_id, arg); |
| 3644 | } |
| 3645 | |
| 3646 | /* The static chain is used as well. */ |
| 3647 | if (gimple_call_chain (stmt)) |
| 3648 | make_constraint_to (callused_id, gimple_call_chain (stmt)); |
| 3649 | |
| 3650 | /* If the call returns a pointer it may point to reachable memory |
| 3651 | from the arguments. Not so for malloc functions though. */ |
| 3652 | if (gimple_call_lhs (stmt) |
| 3653 | && could_have_pointers (gimple_call_lhs (stmt)) |
| 3654 | && !(gimple_call_flags (stmt) & ECF_MALLOC)) |
| 3655 | { |
| 3656 | tree lhs = gimple_call_lhs (stmt); |
| 3657 | VEC(ce_s, heap) *lhsc = NULL; |
| 3658 | struct constraint_expr rhsc; |
| 3659 | struct constraint_expr *lhsp; |
| 3660 | unsigned j; |
| 3661 | |
| 3662 | get_constraint_for (lhs, &lhsc); |
| 3663 | |
| 3664 | /* If this is a nested function then it can return anything. */ |
| 3665 | if (gimple_call_chain (stmt)) |
| 3666 | { |
| 3667 | rhsc.var = anything_id; |
| 3668 | rhsc.offset = 0; |
| 3669 | rhsc.type = ADDRESSOF; |
| 3670 | for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++) |
| 3671 | process_constraint (new_constraint (*lhsp, rhsc)); |
| 3672 | VEC_free (ce_s, heap, lhsc); |
| 3673 | return; |
| 3674 | } |
| 3675 | |
| 3676 | /* Else just add the call-used memory here. Escaped variables |
| 3677 | and globals will be dealt with in handle_lhs_call. */ |
| 3678 | rhsc.var = callused_id; |
| 3679 | rhsc.offset = 0; |
| 3680 | rhsc.type = ADDRESSOF; |
| 3681 | for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++) |
| 3682 | process_constraint (new_constraint (*lhsp, rhsc)); |
| 3683 | VEC_free (ce_s, heap, lhsc); |
| 3684 | } |
| 3685 | } |
| 3686 | |
| 3687 | /* Walk statement T setting up aliasing constraints according to the |
| 3688 | references found in T. This function is the main part of the |
| 3689 | constraint builder. AI points to auxiliary alias information used |
| 3690 | when building alias sets and computing alias grouping heuristics. */ |
| 3691 | |
| 3692 | static void |
| 3693 | find_func_aliases (gimple origt) |
| 3694 | { |
| 3695 | gimple t = origt; |
| 3696 | VEC(ce_s, heap) *lhsc = NULL; |
| 3697 | VEC(ce_s, heap) *rhsc = NULL; |
| 3698 | struct constraint_expr *c; |
| 3699 | enum escape_type stmt_escape_type; |
| 3700 | |
| 3701 | /* Now build constraints expressions. */ |
| 3702 | if (gimple_code (t) == GIMPLE_PHI) |
| 3703 | { |
| 3704 | gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (gimple_phi_result (t)))); |
| 3705 | |
| 3706 | /* Only care about pointers and structures containing |
| 3707 | pointers. */ |
| 3708 | if (could_have_pointers (gimple_phi_result (t))) |
| 3709 | { |
| 3710 | size_t i; |
| 3711 | unsigned int j; |
| 3712 | |
| 3713 | /* For a phi node, assign all the arguments to |
| 3714 | the result. */ |
| 3715 | get_constraint_for (gimple_phi_result (t), &lhsc); |
| 3716 | for (i = 0; i < gimple_phi_num_args (t); i++) |
| 3717 | { |
| 3718 | tree rhstype; |
| 3719 | tree strippedrhs = PHI_ARG_DEF (t, i); |
| 3720 | |
| 3721 | STRIP_NOPS (strippedrhs); |
| 3722 | rhstype = TREE_TYPE (strippedrhs); |
| 3723 | get_constraint_for (gimple_phi_arg_def (t, i), &rhsc); |
| 3724 | |
| 3725 | for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++) |
| 3726 | { |
| 3727 | struct constraint_expr *c2; |
| 3728 | while (VEC_length (ce_s, rhsc) > 0) |
| 3729 | { |
| 3730 | c2 = VEC_last (ce_s, rhsc); |
| 3731 | process_constraint (new_constraint (*c, *c2)); |
| 3732 | VEC_pop (ce_s, rhsc); |
| 3733 | } |
| 3734 | } |
| 3735 | } |
| 3736 | } |
| 3737 | } |
| 3738 | /* In IPA mode, we need to generate constraints to pass call |
| 3739 | arguments through their calls. There are two cases, |
| 3740 | either a GIMPLE_CALL returning a value, or just a plain |
| 3741 | GIMPLE_CALL when we are not. |
| 3742 | |
| 3743 | In non-ipa mode, we need to generate constraints for each |
| 3744 | pointer passed by address. */ |
| 3745 | else if (is_gimple_call (t)) |
| 3746 | { |
| 3747 | if (!in_ipa_mode) |
| 3748 | { |
| 3749 | int flags = gimple_call_flags (t); |
| 3750 | |
| 3751 | /* Const functions can return their arguments and addresses |
| 3752 | of global memory but not of escaped memory. */ |
| 3753 | if (flags & ECF_CONST) |
| 3754 | { |
| 3755 | if (gimple_call_lhs (t) |
| 3756 | && could_have_pointers (gimple_call_lhs (t))) |
| 3757 | handle_const_call (t); |
| 3758 | } |
| 3759 | /* Pure functions can return addresses in and of memory |
| 3760 | reachable from their arguments, but they are not an escape |
| 3761 | point for reachable memory of their arguments. */ |
| 3762 | else if (flags & ECF_PURE) |
| 3763 | { |
| 3764 | handle_pure_call (t); |
| 3765 | if (gimple_call_lhs (t) |
| 3766 | && could_have_pointers (gimple_call_lhs (t))) |
| 3767 | handle_lhs_call (gimple_call_lhs (t), flags); |
| 3768 | } |
| 3769 | else |
| 3770 | { |
| 3771 | handle_rhs_call (t); |
| 3772 | if (gimple_call_lhs (t) |
| 3773 | && could_have_pointers (gimple_call_lhs (t))) |
| 3774 | handle_lhs_call (gimple_call_lhs (t), flags); |
| 3775 | } |
| 3776 | } |
| 3777 | else |
| 3778 | { |
| 3779 | tree lhsop; |
| 3780 | varinfo_t fi; |
| 3781 | int i = 1; |
| 3782 | size_t j; |
| 3783 | tree decl; |
| 3784 | |
| 3785 | lhsop = gimple_call_lhs (t); |
| 3786 | decl = gimple_call_fndecl (t); |
| 3787 | |
| 3788 | /* If we can directly resolve the function being called, do so. |
| 3789 | Otherwise, it must be some sort of indirect expression that |
| 3790 | we should still be able to handle. */ |
| 3791 | if (decl) |
| 3792 | fi = get_vi_for_tree (decl); |
| 3793 | else |
| 3794 | { |
| 3795 | decl = gimple_call_fn (t); |
| 3796 | fi = get_vi_for_tree (decl); |
| 3797 | } |
| 3798 | |
| 3799 | /* Assign all the passed arguments to the appropriate incoming |
| 3800 | parameters of the function. */ |
| 3801 | for (j = 0; j < gimple_call_num_args (t); j++) |
| 3802 | { |
| 3803 | struct constraint_expr lhs ; |
| 3804 | struct constraint_expr *rhsp; |
| 3805 | tree arg = gimple_call_arg (t, j); |
| 3806 | |
| 3807 | get_constraint_for (arg, &rhsc); |
| 3808 | if (TREE_CODE (decl) != FUNCTION_DECL) |
| 3809 | { |
| 3810 | lhs.type = DEREF; |
| 3811 | lhs.var = fi->id; |
| 3812 | lhs.offset = i; |
| 3813 | } |
| 3814 | else |
| 3815 | { |
| 3816 | lhs.type = SCALAR; |
| 3817 | lhs.var = first_vi_for_offset (fi, i)->id; |
| 3818 | lhs.offset = 0; |
| 3819 | } |
| 3820 | while (VEC_length (ce_s, rhsc) != 0) |
| 3821 | { |
| 3822 | rhsp = VEC_last (ce_s, rhsc); |
| 3823 | process_constraint (new_constraint (lhs, *rhsp)); |
| 3824 | VEC_pop (ce_s, rhsc); |
| 3825 | } |
| 3826 | i++; |
| 3827 | } |
| 3828 | |
| 3829 | /* If we are returning a value, assign it to the result. */ |
| 3830 | if (lhsop) |
| 3831 | { |
| 3832 | struct constraint_expr rhs; |
| 3833 | struct constraint_expr *lhsp; |
| 3834 | unsigned int j = 0; |
| 3835 | |
| 3836 | get_constraint_for (lhsop, &lhsc); |
| 3837 | if (TREE_CODE (decl) != FUNCTION_DECL) |
| 3838 | { |
| 3839 | rhs.type = DEREF; |
| 3840 | rhs.var = fi->id; |
| 3841 | rhs.offset = i; |
| 3842 | } |
| 3843 | else |
| 3844 | { |
| 3845 | rhs.type = SCALAR; |
| 3846 | rhs.var = first_vi_for_offset (fi, i)->id; |
| 3847 | rhs.offset = 0; |
| 3848 | } |
| 3849 | for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++) |
| 3850 | process_constraint (new_constraint (*lhsp, rhs)); |
| 3851 | } |
| 3852 | } |
| 3853 | } |
| 3854 | /* Otherwise, just a regular assignment statement. Only care about |
| 3855 | operations with pointer result, others are dealt with as escape |
| 3856 | points if they have pointer operands. */ |
| 3857 | else if (is_gimple_assign (t) |
| 3858 | && could_have_pointers (gimple_assign_lhs (t))) |
| 3859 | { |
| 3860 | /* Otherwise, just a regular assignment statement. */ |
| 3861 | tree lhsop = gimple_assign_lhs (t); |
| 3862 | tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL; |
| 3863 | |
| 3864 | if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop))) |
| 3865 | do_structure_copy (lhsop, rhsop); |
| 3866 | else |
| 3867 | { |
| 3868 | unsigned int j; |
| 3869 | struct constraint_expr temp; |
| 3870 | get_constraint_for (lhsop, &lhsc); |
| 3871 | |
| 3872 | if (gimple_assign_rhs_code (t) == POINTER_PLUS_EXPR) |
| 3873 | get_constraint_for_ptr_offset (gimple_assign_rhs1 (t), |
| 3874 | gimple_assign_rhs2 (t), &rhsc); |
| 3875 | else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t)) |
| 3876 | && !(POINTER_TYPE_P (gimple_expr_type (t)) |
| 3877 | && !POINTER_TYPE_P (TREE_TYPE (rhsop)))) |
| 3878 | || gimple_assign_single_p (t)) |
| 3879 | get_constraint_for (rhsop, &rhsc); |
| 3880 | else |
| 3881 | { |
| 3882 | temp.type = ADDRESSOF; |
| 3883 | temp.var = anything_id; |
| 3884 | temp.offset = 0; |
| 3885 | VEC_safe_push (ce_s, heap, rhsc, &temp); |
| 3886 | } |
| 3887 | for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++) |
| 3888 | { |
| 3889 | struct constraint_expr *c2; |
| 3890 | unsigned int k; |
| 3891 | |
| 3892 | for (k = 0; VEC_iterate (ce_s, rhsc, k, c2); k++) |
| 3893 | process_constraint (new_constraint (*c, *c2)); |
| 3894 | } |
| 3895 | } |
| 3896 | } |
| 3897 | else if (gimple_code (t) == GIMPLE_CHANGE_DYNAMIC_TYPE) |
| 3898 | { |
| 3899 | unsigned int j; |
| 3900 | |
| 3901 | get_constraint_for (gimple_cdt_location (t), &lhsc); |
| 3902 | for (j = 0; VEC_iterate (ce_s, lhsc, j, c); ++j) |
| 3903 | get_varinfo (c->var)->no_tbaa_pruning = true; |
| 3904 | } |
| 3905 | |
| 3906 | stmt_escape_type = is_escape_site (t); |
| 3907 | if (stmt_escape_type == ESCAPE_STORED_IN_GLOBAL) |
| 3908 | { |
| 3909 | gcc_assert (is_gimple_assign (t)); |
| 3910 | if (gimple_assign_rhs_code (t) == ADDR_EXPR) |
| 3911 | { |
| 3912 | tree rhs = gimple_assign_rhs1 (t); |
| 3913 | tree base = get_base_address (TREE_OPERAND (rhs, 0)); |
| 3914 | if (base |
| 3915 | && (!DECL_P (base) |
| 3916 | || !is_global_var (base))) |
| 3917 | make_escape_constraint (rhs); |
| 3918 | } |
| 3919 | else if (get_gimple_rhs_class (gimple_assign_rhs_code (t)) |
| 3920 | == GIMPLE_SINGLE_RHS) |
| 3921 | { |
| 3922 | if (could_have_pointers (gimple_assign_rhs1 (t))) |
| 3923 | make_escape_constraint (gimple_assign_rhs1 (t)); |
| 3924 | } |
| 3925 | else |
| 3926 | gcc_unreachable (); |
| 3927 | } |
| 3928 | else if (stmt_escape_type == ESCAPE_BAD_CAST) |
| 3929 | { |
| 3930 | gcc_assert (is_gimple_assign (t)); |
| 3931 | gcc_assert (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t)) |
| 3932 | || gimple_assign_rhs_code (t) == VIEW_CONVERT_EXPR); |
| 3933 | make_escape_constraint (gimple_assign_rhs1 (t)); |
| 3934 | } |
| 3935 | else if (stmt_escape_type == ESCAPE_TO_ASM) |
| 3936 | { |
| 3937 | unsigned i; |
| 3938 | for (i = 0; i < gimple_asm_noutputs (t); ++i) |
| 3939 | { |
| 3940 | tree op = TREE_VALUE (gimple_asm_output_op (t, i)); |
| 3941 | if (op && could_have_pointers (op)) |
| 3942 | /* Strictly we'd only need the constraints from ESCAPED and |
| 3943 | NONLOCAL. */ |
| 3944 | make_escape_constraint (op); |
| 3945 | } |
| 3946 | for (i = 0; i < gimple_asm_ninputs (t); ++i) |
| 3947 | { |
| 3948 | tree op = TREE_VALUE (gimple_asm_input_op (t, i)); |
| 3949 | if (op && could_have_pointers (op)) |
| 3950 | /* Strictly we'd only need the constraint to ESCAPED. */ |
| 3951 | make_escape_constraint (op); |
| 3952 | } |
| 3953 | } |
| 3954 | |
| 3955 | /* After promoting variables and computing aliasing we will |
| 3956 | need to re-scan most statements. FIXME: Try to minimize the |
| 3957 | number of statements re-scanned. It's not really necessary to |
| 3958 | re-scan *all* statements. */ |
| 3959 | if (!in_ipa_mode) |
| 3960 | gimple_set_modified (origt, true); |
| 3961 | VEC_free (ce_s, heap, rhsc); |
| 3962 | VEC_free (ce_s, heap, lhsc); |
| 3963 | } |
| 3964 | |
| 3965 | |
| 3966 | /* Find the first varinfo in the same variable as START that overlaps with |
| 3967 | OFFSET. |
| 3968 | Effectively, walk the chain of fields for the variable START to find the |
| 3969 | first field that overlaps with OFFSET. |
| 3970 | Return NULL if we can't find one. */ |
| 3971 | |
| 3972 | static varinfo_t |
| 3973 | first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset) |
| 3974 | { |
| 3975 | varinfo_t curr = start; |
| 3976 | while (curr) |
| 3977 | { |
| 3978 | /* We may not find a variable in the field list with the actual |
| 3979 | offset when when we have glommed a structure to a variable. |
| 3980 | In that case, however, offset should still be within the size |
| 3981 | of the variable. */ |
| 3982 | if (offset >= curr->offset && offset < (curr->offset + curr->size)) |
| 3983 | return curr; |
| 3984 | curr = curr->next; |
| 3985 | } |
| 3986 | return NULL; |
| 3987 | } |
| 3988 | |
| 3989 | |
| 3990 | /* Insert the varinfo FIELD into the field list for BASE, at the front |
| 3991 | of the list. */ |
| 3992 | |
| 3993 | static void |
| 3994 | insert_into_field_list (varinfo_t base, varinfo_t field) |
| 3995 | { |
| 3996 | varinfo_t prev = base; |
| 3997 | varinfo_t curr = base->next; |
| 3998 | |
| 3999 | field->next = curr; |
| 4000 | prev->next = field; |
| 4001 | } |
| 4002 | |
| 4003 | /* Insert the varinfo FIELD into the field list for BASE, ordered by |
| 4004 | offset. */ |
| 4005 | |
| 4006 | static void |
| 4007 | insert_into_field_list_sorted (varinfo_t base, varinfo_t field) |
| 4008 | { |
| 4009 | varinfo_t prev = base; |
| 4010 | varinfo_t curr = base->next; |
| 4011 | |
| 4012 | if (curr == NULL) |
| 4013 | { |
| 4014 | prev->next = field; |
| 4015 | field->next = NULL; |
| 4016 | } |
| 4017 | else |
| 4018 | { |
| 4019 | while (curr) |
| 4020 | { |
| 4021 | if (field->offset <= curr->offset) |
| 4022 | break; |
| 4023 | prev = curr; |
| 4024 | curr = curr->next; |
| 4025 | } |
| 4026 | field->next = prev->next; |
| 4027 | prev->next = field; |
| 4028 | } |
| 4029 | } |
| 4030 | |
| 4031 | /* This structure is used during pushing fields onto the fieldstack |
| 4032 | to track the offset of the field, since bitpos_of_field gives it |
| 4033 | relative to its immediate containing type, and we want it relative |
| 4034 | to the ultimate containing object. */ |
| 4035 | |
| 4036 | struct fieldoff |
| 4037 | { |
| 4038 | /* Offset from the base of the base containing object to this field. */ |
| 4039 | HOST_WIDE_INT offset; |
| 4040 | |
| 4041 | /* Size, in bits, of the field. */ |
| 4042 | unsigned HOST_WIDE_INT size; |
| 4043 | |
| 4044 | unsigned has_unknown_size : 1; |
| 4045 | |
| 4046 | unsigned may_have_pointers : 1; |
| 4047 | }; |
| 4048 | typedef struct fieldoff fieldoff_s; |
| 4049 | |
| 4050 | DEF_VEC_O(fieldoff_s); |
| 4051 | DEF_VEC_ALLOC_O(fieldoff_s,heap); |
| 4052 | |
| 4053 | /* qsort comparison function for two fieldoff's PA and PB */ |
| 4054 | |
| 4055 | static int |
| 4056 | fieldoff_compare (const void *pa, const void *pb) |
| 4057 | { |
| 4058 | const fieldoff_s *foa = (const fieldoff_s *)pa; |
| 4059 | const fieldoff_s *fob = (const fieldoff_s *)pb; |
| 4060 | unsigned HOST_WIDE_INT foasize, fobsize; |
| 4061 | |
| 4062 | if (foa->offset < fob->offset) |
| 4063 | return -1; |
| 4064 | else if (foa->offset > fob->offset) |
| 4065 | return 1; |
| 4066 | |
| 4067 | foasize = foa->size; |
| 4068 | fobsize = fob->size; |
| 4069 | if (foasize < fobsize) |
| 4070 | return -1; |
| 4071 | else if (foasize > fobsize) |
| 4072 | return 1; |
| 4073 | return 0; |
| 4074 | } |
| 4075 | |
| 4076 | /* Sort a fieldstack according to the field offset and sizes. */ |
| 4077 | static void |
| 4078 | sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack) |
| 4079 | { |
| 4080 | qsort (VEC_address (fieldoff_s, fieldstack), |
| 4081 | VEC_length (fieldoff_s, fieldstack), |
| 4082 | sizeof (fieldoff_s), |
| 4083 | fieldoff_compare); |
| 4084 | } |
| 4085 | |
| 4086 | /* Return true if V is a tree that we can have subvars for. |
| 4087 | Normally, this is any aggregate type. Also complex |
| 4088 | types which are not gimple registers can have subvars. */ |
| 4089 | |
| 4090 | static inline bool |
| 4091 | var_can_have_subvars (const_tree v) |
| 4092 | { |
| 4093 | /* Volatile variables should never have subvars. */ |
| 4094 | if (TREE_THIS_VOLATILE (v)) |
| 4095 | return false; |
| 4096 | |
| 4097 | /* Non decls or memory tags can never have subvars. */ |
| 4098 | if (!DECL_P (v) || MTAG_P (v)) |
| 4099 | return false; |
| 4100 | |
| 4101 | /* Aggregates without overlapping fields can have subvars. */ |
| 4102 | if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE) |
| 4103 | return true; |
| 4104 | |
| 4105 | return false; |
| 4106 | } |
| 4107 | |
| 4108 | /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all |
| 4109 | the fields of TYPE onto fieldstack, recording their offsets along |
| 4110 | the way. |
| 4111 | |
| 4112 | OFFSET is used to keep track of the offset in this entire |
| 4113 | structure, rather than just the immediately containing structure. |
| 4114 | Returns the number of fields pushed. */ |
| 4115 | |
| 4116 | static int |
| 4117 | push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack, |
| 4118 | HOST_WIDE_INT offset) |
| 4119 | { |
| 4120 | tree field; |
| 4121 | int count = 0; |
| 4122 | |
| 4123 | if (TREE_CODE (type) != RECORD_TYPE) |
| 4124 | return 0; |
| 4125 | |
| 4126 | /* If the vector of fields is growing too big, bail out early. |
| 4127 | Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make |
| 4128 | sure this fails. */ |
| 4129 | if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE) |
| 4130 | return 0; |
| 4131 | |
| 4132 | for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field)) |
| 4133 | if (TREE_CODE (field) == FIELD_DECL) |
| 4134 | { |
| 4135 | bool push = false; |
| 4136 | int pushed = 0; |
| 4137 | HOST_WIDE_INT foff = bitpos_of_field (field); |
| 4138 | |
| 4139 | if (!var_can_have_subvars (field) |
| 4140 | || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE |
| 4141 | || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE) |
| 4142 | push = true; |
| 4143 | else if (!(pushed = push_fields_onto_fieldstack |
| 4144 | (TREE_TYPE (field), fieldstack, offset + foff)) |
| 4145 | && (DECL_SIZE (field) |
| 4146 | && !integer_zerop (DECL_SIZE (field)))) |
| 4147 | /* Empty structures may have actual size, like in C++. So |
| 4148 | see if we didn't push any subfields and the size is |
| 4149 | nonzero, push the field onto the stack. */ |
| 4150 | push = true; |
| 4151 | |
| 4152 | if (push) |
| 4153 | { |
| 4154 | fieldoff_s *pair = NULL; |
| 4155 | bool has_unknown_size = false; |
| 4156 | |
| 4157 | if (!VEC_empty (fieldoff_s, *fieldstack)) |
| 4158 | pair = VEC_last (fieldoff_s, *fieldstack); |
| 4159 | |
| 4160 | if (!DECL_SIZE (field) |
| 4161 | || !host_integerp (DECL_SIZE (field), 1)) |
| 4162 | has_unknown_size = true; |
| 4163 | |
| 4164 | /* If adjacent fields do not contain pointers merge them. */ |
| 4165 | if (pair |
| 4166 | && !pair->may_have_pointers |
| 4167 | && !could_have_pointers (field) |
| 4168 | && !pair->has_unknown_size |
| 4169 | && !has_unknown_size |
| 4170 | && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff) |
| 4171 | { |
| 4172 | pair = VEC_last (fieldoff_s, *fieldstack); |
| 4173 | pair->size += TREE_INT_CST_LOW (DECL_SIZE (field)); |
| 4174 | } |
| 4175 | else |
| 4176 | { |
| 4177 | pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL); |
| 4178 | pair->offset = offset + foff; |
| 4179 | pair->has_unknown_size = has_unknown_size; |
| 4180 | if (!has_unknown_size) |
| 4181 | pair->size = TREE_INT_CST_LOW (DECL_SIZE (field)); |
| 4182 | else |
| 4183 | pair->size = -1; |
| 4184 | pair->may_have_pointers = could_have_pointers (field); |
| 4185 | count++; |
| 4186 | } |
| 4187 | } |
| 4188 | else |
| 4189 | count += pushed; |
| 4190 | } |
| 4191 | |
| 4192 | return count; |
| 4193 | } |
| 4194 | |
| 4195 | /* Create a constraint ID = &FROM. */ |
| 4196 | |
| 4197 | static void |
| 4198 | make_constraint_from (varinfo_t vi, int from) |
| 4199 | { |
| 4200 | struct constraint_expr lhs, rhs; |
| 4201 | |
| 4202 | lhs.var = vi->id; |
| 4203 | lhs.offset = 0; |
| 4204 | lhs.type = SCALAR; |
| 4205 | |
| 4206 | rhs.var = from; |
| 4207 | rhs.offset = 0; |
| 4208 | rhs.type = ADDRESSOF; |
| 4209 | process_constraint (new_constraint (lhs, rhs)); |
| 4210 | } |
| 4211 | |
| 4212 | /* Count the number of arguments DECL has, and set IS_VARARGS to true |
| 4213 | if it is a varargs function. */ |
| 4214 | |
| 4215 | static unsigned int |
| 4216 | count_num_arguments (tree decl, bool *is_varargs) |
| 4217 | { |
| 4218 | unsigned int i = 0; |
| 4219 | tree t; |
| 4220 | |
| 4221 | for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); |
| 4222 | t; |
| 4223 | t = TREE_CHAIN (t)) |
| 4224 | { |
| 4225 | if (TREE_VALUE (t) == void_type_node) |
| 4226 | break; |
| 4227 | i++; |
| 4228 | } |
| 4229 | |
| 4230 | if (!t) |
| 4231 | *is_varargs = true; |
| 4232 | return i; |
| 4233 | } |
| 4234 | |
| 4235 | /* Creation function node for DECL, using NAME, and return the index |
| 4236 | of the variable we've created for the function. */ |
| 4237 | |
| 4238 | static unsigned int |
| 4239 | create_function_info_for (tree decl, const char *name) |
| 4240 | { |
| 4241 | unsigned int index = VEC_length (varinfo_t, varmap); |
| 4242 | varinfo_t vi; |
| 4243 | tree arg; |
| 4244 | unsigned int i; |
| 4245 | bool is_varargs = false; |
| 4246 | |
| 4247 | /* Create the variable info. */ |
| 4248 | |
| 4249 | vi = new_var_info (decl, index, name); |
| 4250 | vi->decl = decl; |
| 4251 | vi->offset = 0; |
| 4252 | vi->size = 1; |
| 4253 | vi->fullsize = count_num_arguments (decl, &is_varargs) + 1; |
| 4254 | insert_vi_for_tree (vi->decl, vi); |
| 4255 | VEC_safe_push (varinfo_t, heap, varmap, vi); |
| 4256 | |
| 4257 | stats.total_vars++; |
| 4258 | |
| 4259 | /* If it's varargs, we don't know how many arguments it has, so we |
| 4260 | can't do much. */ |
| 4261 | if (is_varargs) |
| 4262 | { |
| 4263 | vi->fullsize = ~0; |
| 4264 | vi->size = ~0; |
| 4265 | vi->is_unknown_size_var = true; |
| 4266 | return index; |
| 4267 | } |
| 4268 | |
| 4269 | |
| 4270 | arg = DECL_ARGUMENTS (decl); |
| 4271 | |
| 4272 | /* Set up variables for each argument. */ |
| 4273 | for (i = 1; i < vi->fullsize; i++) |
| 4274 | { |
| 4275 | varinfo_t argvi; |
| 4276 | const char *newname; |
| 4277 | char *tempname; |
| 4278 | unsigned int newindex; |
| 4279 | tree argdecl = decl; |
| 4280 | |
| 4281 | if (arg) |
| 4282 | argdecl = arg; |
| 4283 | |
| 4284 | newindex = VEC_length (varinfo_t, varmap); |
| 4285 | asprintf (&tempname, "%s.arg%d", name, i-1); |
| 4286 | newname = ggc_strdup (tempname); |
| 4287 | free (tempname); |
| 4288 | |
| 4289 | argvi = new_var_info (argdecl, newindex, newname); |
| 4290 | argvi->decl = argdecl; |
| 4291 | VEC_safe_push (varinfo_t, heap, varmap, argvi); |
| 4292 | argvi->offset = i; |
| 4293 | argvi->size = 1; |
| 4294 | argvi->is_full_var = true; |
| 4295 | argvi->fullsize = vi->fullsize; |
| 4296 | insert_into_field_list_sorted (vi, argvi); |
| 4297 | stats.total_vars ++; |
| 4298 | if (arg) |
| 4299 | { |
| 4300 | insert_vi_for_tree (arg, argvi); |
| 4301 | arg = TREE_CHAIN (arg); |
| 4302 | } |
| 4303 | } |
| 4304 | |
| 4305 | /* Create a variable for the return var. */ |
| 4306 | if (DECL_RESULT (decl) != NULL |
| 4307 | || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl)))) |
| 4308 | { |
| 4309 | varinfo_t resultvi; |
| 4310 | const char *newname; |
| 4311 | char *tempname; |
| 4312 | unsigned int newindex; |
| 4313 | tree resultdecl = decl; |
| 4314 | |
| 4315 | vi->fullsize ++; |
| 4316 | |
| 4317 | if (DECL_RESULT (decl)) |
| 4318 | resultdecl = DECL_RESULT (decl); |
| 4319 | |
| 4320 | newindex = VEC_length (varinfo_t, varmap); |
| 4321 | asprintf (&tempname, "%s.result", name); |
| 4322 | newname = ggc_strdup (tempname); |
| 4323 | free (tempname); |
| 4324 | |
| 4325 | resultvi = new_var_info (resultdecl, newindex, newname); |
| 4326 | resultvi->decl = resultdecl; |
| 4327 | VEC_safe_push (varinfo_t, heap, varmap, resultvi); |
| 4328 | resultvi->offset = i; |
| 4329 | resultvi->size = 1; |
| 4330 | resultvi->fullsize = vi->fullsize; |
| 4331 | resultvi->is_full_var = true; |
| 4332 | insert_into_field_list_sorted (vi, resultvi); |
| 4333 | stats.total_vars ++; |
| 4334 | if (DECL_RESULT (decl)) |
| 4335 | insert_vi_for_tree (DECL_RESULT (decl), resultvi); |
| 4336 | } |
| 4337 | return index; |
| 4338 | } |
| 4339 | |
| 4340 | |
| 4341 | /* Return true if FIELDSTACK contains fields that overlap. |
| 4342 | FIELDSTACK is assumed to be sorted by offset. */ |
| 4343 | |
| 4344 | static bool |
| 4345 | check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack) |
| 4346 | { |
| 4347 | fieldoff_s *fo = NULL; |
| 4348 | unsigned int i; |
| 4349 | HOST_WIDE_INT lastoffset = -1; |
| 4350 | |
| 4351 | for (i = 0; VEC_iterate (fieldoff_s, fieldstack, i, fo); i++) |
| 4352 | { |
| 4353 | if (fo->offset == lastoffset) |
| 4354 | return true; |
| 4355 | lastoffset = fo->offset; |
| 4356 | } |
| 4357 | return false; |
| 4358 | } |
| 4359 | |
| 4360 | /* Create a varinfo structure for NAME and DECL, and add it to VARMAP. |
| 4361 | This will also create any varinfo structures necessary for fields |
| 4362 | of DECL. */ |
| 4363 | |
| 4364 | static unsigned int |
| 4365 | create_variable_info_for (tree decl, const char *name) |
| 4366 | { |
| 4367 | unsigned int index = VEC_length (varinfo_t, varmap); |
| 4368 | varinfo_t vi; |
| 4369 | tree decl_type = TREE_TYPE (decl); |
| 4370 | tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type); |
| 4371 | bool is_global = DECL_P (decl) ? is_global_var (decl) : false; |
| 4372 | VEC (fieldoff_s,heap) *fieldstack = NULL; |
| 4373 | |
| 4374 | if (TREE_CODE (decl) == FUNCTION_DECL && in_ipa_mode) |
| 4375 | return create_function_info_for (decl, name); |
| 4376 | |
| 4377 | if (var_can_have_subvars (decl) && use_field_sensitive |
| 4378 | && (!var_ann (decl) |
| 4379 | || var_ann (decl)->noalias_state == 0) |
| 4380 | && (!var_ann (decl) |
| 4381 | || !var_ann (decl)->is_heapvar)) |
| 4382 | push_fields_onto_fieldstack (decl_type, &fieldstack, 0); |
| 4383 | |
| 4384 | /* If the variable doesn't have subvars, we may end up needing to |
| 4385 | sort the field list and create fake variables for all the |
| 4386 | fields. */ |
| 4387 | vi = new_var_info (decl, index, name); |
| 4388 | vi->decl = decl; |
| 4389 | vi->offset = 0; |
| 4390 | vi->may_have_pointers = could_have_pointers (decl); |
| 4391 | if (!declsize |
| 4392 | || !host_integerp (declsize, 1)) |
| 4393 | { |
| 4394 | vi->is_unknown_size_var = true; |
| 4395 | vi->fullsize = ~0; |
| 4396 | vi->size = ~0; |
| 4397 | } |
| 4398 | else |
| 4399 | { |
| 4400 | vi->fullsize = TREE_INT_CST_LOW (declsize); |
| 4401 | vi->size = vi->fullsize; |
| 4402 | } |
| 4403 | |
| 4404 | insert_vi_for_tree (vi->decl, vi); |
| 4405 | VEC_safe_push (varinfo_t, heap, varmap, vi); |
| 4406 | if (is_global && (!flag_whole_program || !in_ipa_mode) |
| 4407 | && vi->may_have_pointers) |
| 4408 | { |
| 4409 | if (var_ann (decl) |
| 4410 | && var_ann (decl)->noalias_state == NO_ALIAS_ANYTHING) |
| 4411 | make_constraint_from (vi, vi->id); |
| 4412 | else |
| 4413 | make_constraint_from (vi, escaped_id); |
| 4414 | } |
| 4415 | |
| 4416 | stats.total_vars++; |
| 4417 | if (use_field_sensitive |
| 4418 | && !vi->is_unknown_size_var |
| 4419 | && var_can_have_subvars (decl) |
| 4420 | && VEC_length (fieldoff_s, fieldstack) > 1 |
| 4421 | && VEC_length (fieldoff_s, fieldstack) <= MAX_FIELDS_FOR_FIELD_SENSITIVE) |
| 4422 | { |
| 4423 | unsigned int newindex = VEC_length (varinfo_t, varmap); |
| 4424 | fieldoff_s *fo = NULL; |
| 4425 | bool notokay = false; |
| 4426 | unsigned int i; |
| 4427 | |
| 4428 | for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++) |
| 4429 | { |
| 4430 | if (fo->has_unknown_size |
| 4431 | || fo->offset < 0) |
| 4432 | { |
| 4433 | notokay = true; |
| 4434 | break; |
| 4435 | } |
| 4436 | } |
| 4437 | |
| 4438 | /* We can't sort them if we have a field with a variable sized type, |
| 4439 | which will make notokay = true. In that case, we are going to return |
| 4440 | without creating varinfos for the fields anyway, so sorting them is a |
| 4441 | waste to boot. */ |
| 4442 | if (!notokay) |
| 4443 | { |
| 4444 | sort_fieldstack (fieldstack); |
| 4445 | /* Due to some C++ FE issues, like PR 22488, we might end up |
| 4446 | what appear to be overlapping fields even though they, |
| 4447 | in reality, do not overlap. Until the C++ FE is fixed, |
| 4448 | we will simply disable field-sensitivity for these cases. */ |
| 4449 | notokay = check_for_overlaps (fieldstack); |
| 4450 | } |
| 4451 | |
| 4452 | |
| 4453 | if (VEC_length (fieldoff_s, fieldstack) != 0) |
| 4454 | fo = VEC_index (fieldoff_s, fieldstack, 0); |
| 4455 | |
| 4456 | if (fo == NULL || notokay) |
| 4457 | { |
| 4458 | vi->is_unknown_size_var = 1; |
| 4459 | vi->fullsize = ~0; |
| 4460 | vi->size = ~0; |
| 4461 | vi->is_full_var = true; |
| 4462 | VEC_free (fieldoff_s, heap, fieldstack); |
| 4463 | return index; |
| 4464 | } |
| 4465 | |
| 4466 | vi->size = fo->size; |
| 4467 | vi->offset = fo->offset; |
| 4468 | vi->may_have_pointers = fo->may_have_pointers; |
| 4469 | for (i = VEC_length (fieldoff_s, fieldstack) - 1; |
| 4470 | i >= 1 && VEC_iterate (fieldoff_s, fieldstack, i, fo); |
| 4471 | i--) |
| 4472 | { |
| 4473 | varinfo_t newvi; |
| 4474 | const char *newname = "NULL"; |
| 4475 | char *tempname; |
| 4476 | |
| 4477 | newindex = VEC_length (varinfo_t, varmap); |
| 4478 | if (dump_file) |
| 4479 | { |
| 4480 | asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC |
| 4481 | "+" HOST_WIDE_INT_PRINT_DEC, |
| 4482 | vi->name, fo->offset, fo->size); |
| 4483 | newname = ggc_strdup (tempname); |
| 4484 | free (tempname); |
| 4485 | } |
| 4486 | newvi = new_var_info (decl, newindex, newname); |
| 4487 | newvi->offset = fo->offset; |
| 4488 | newvi->size = fo->size; |
| 4489 | newvi->fullsize = vi->fullsize; |
| 4490 | newvi->may_have_pointers = fo->may_have_pointers; |
| 4491 | insert_into_field_list (vi, newvi); |
| 4492 | VEC_safe_push (varinfo_t, heap, varmap, newvi); |
| 4493 | if (is_global && (!flag_whole_program || !in_ipa_mode) |
| 4494 | && newvi->may_have_pointers) |
| 4495 | make_constraint_from (newvi, escaped_id); |
| 4496 | |
| 4497 | stats.total_vars++; |
| 4498 | } |
| 4499 | } |
| 4500 | else |
| 4501 | vi->is_full_var = true; |
| 4502 | |
| 4503 | VEC_free (fieldoff_s, heap, fieldstack); |
| 4504 | |
| 4505 | return index; |
| 4506 | } |
| 4507 | |
| 4508 | /* Print out the points-to solution for VAR to FILE. */ |
| 4509 | |
| 4510 | void |
| 4511 | dump_solution_for_var (FILE *file, unsigned int var) |
| 4512 | { |
| 4513 | varinfo_t vi = get_varinfo (var); |
| 4514 | unsigned int i; |
| 4515 | bitmap_iterator bi; |
| 4516 | |
| 4517 | if (find (var) != var) |
| 4518 | { |
| 4519 | varinfo_t vipt = get_varinfo (find (var)); |
| 4520 | fprintf (file, "%s = same as %s\n", vi->name, vipt->name); |
| 4521 | } |
| 4522 | else |
| 4523 | { |
| 4524 | fprintf (file, "%s = { ", vi->name); |
| 4525 | EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi) |
| 4526 | { |
| 4527 | fprintf (file, "%s ", get_varinfo (i)->name); |
| 4528 | } |
| 4529 | fprintf (file, "}"); |
| 4530 | if (vi->no_tbaa_pruning) |
| 4531 | fprintf (file, " no-tbaa-pruning"); |
| 4532 | fprintf (file, "\n"); |
| 4533 | } |
| 4534 | } |
| 4535 | |
| 4536 | /* Print the points-to solution for VAR to stdout. */ |
| 4537 | |
| 4538 | void |
| 4539 | debug_solution_for_var (unsigned int var) |
| 4540 | { |
| 4541 | dump_solution_for_var (stdout, var); |
| 4542 | } |
| 4543 | |
| 4544 | /* Create varinfo structures for all of the variables in the |
| 4545 | function for intraprocedural mode. */ |
| 4546 | |
| 4547 | static void |
| 4548 | intra_create_variable_infos (void) |
| 4549 | { |
| 4550 | tree t; |
| 4551 | struct constraint_expr lhs, rhs; |
| 4552 | |
| 4553 | /* For each incoming pointer argument arg, create the constraint ARG |
| 4554 | = NONLOCAL or a dummy variable if flag_argument_noalias is set. */ |
| 4555 | for (t = DECL_ARGUMENTS (current_function_decl); t; t = TREE_CHAIN (t)) |
| 4556 | { |
| 4557 | varinfo_t p; |
| 4558 | |
| 4559 | if (!could_have_pointers (t)) |
| 4560 | continue; |
| 4561 | |
| 4562 | /* If flag_argument_noalias is set, then function pointer |
| 4563 | arguments are guaranteed not to point to each other. In that |
| 4564 | case, create an artificial variable PARM_NOALIAS and the |
| 4565 | constraint ARG = &PARM_NOALIAS. */ |
| 4566 | if (POINTER_TYPE_P (TREE_TYPE (t)) && flag_argument_noalias > 0) |
| 4567 | { |
| 4568 | varinfo_t vi; |
| 4569 | tree heapvar = heapvar_lookup (t); |
| 4570 | |
| 4571 | lhs.offset = 0; |
| 4572 | lhs.type = SCALAR; |
| 4573 | lhs.var = get_vi_for_tree (t)->id; |
| 4574 | |
| 4575 | if (heapvar == NULL_TREE) |
| 4576 | { |
| 4577 | var_ann_t ann; |
| 4578 | heapvar = create_tmp_var_raw (ptr_type_node, |
| 4579 | "PARM_NOALIAS"); |
| 4580 | DECL_EXTERNAL (heapvar) = 1; |
| 4581 | if (gimple_referenced_vars (cfun)) |
| 4582 | add_referenced_var (heapvar); |
| 4583 | |
| 4584 | heapvar_insert (t, heapvar); |
| 4585 | |
| 4586 | ann = get_var_ann (heapvar); |
| 4587 | ann->is_heapvar = 1; |
| 4588 | if (flag_argument_noalias == 1) |
| 4589 | ann->noalias_state = NO_ALIAS; |
| 4590 | else if (flag_argument_noalias == 2) |
| 4591 | ann->noalias_state = NO_ALIAS_GLOBAL; |
| 4592 | else if (flag_argument_noalias == 3) |
| 4593 | ann->noalias_state = NO_ALIAS_ANYTHING; |
| 4594 | else |
| 4595 | gcc_unreachable (); |
| 4596 | } |
| 4597 | |
| 4598 | vi = get_vi_for_tree (heapvar); |
| 4599 | vi->is_artificial_var = 1; |
| 4600 | vi->is_heap_var = 1; |
| 4601 | vi->is_unknown_size_var = true; |
| 4602 | vi->fullsize = ~0; |
| 4603 | vi->size = ~0; |
| 4604 | rhs.var = vi->id; |
| 4605 | rhs.type = ADDRESSOF; |
| 4606 | rhs.offset = 0; |
| 4607 | for (p = get_varinfo (lhs.var); p; p = p->next) |
| 4608 | { |
| 4609 | struct constraint_expr temp = lhs; |
| 4610 | temp.var = p->id; |
| 4611 | process_constraint (new_constraint (temp, rhs)); |
| 4612 | } |
| 4613 | } |
| 4614 | else |
| 4615 | { |
| 4616 | varinfo_t arg_vi = get_vi_for_tree (t); |
| 4617 | |
| 4618 | for (p = arg_vi; p; p = p->next) |
| 4619 | make_constraint_from (p, nonlocal_id); |
| 4620 | } |
| 4621 | } |
| 4622 | |
| 4623 | /* Add a constraint for a result decl that is passed by reference. */ |
| 4624 | if (DECL_RESULT (cfun->decl) |
| 4625 | && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl))) |
| 4626 | { |
| 4627 | varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl)); |
| 4628 | |
| 4629 | for (p = result_vi; p; p = p->next) |
| 4630 | make_constraint_from (p, nonlocal_id); |
| 4631 | } |
| 4632 | |
| 4633 | /* Add a constraint for the incoming static chain parameter. */ |
| 4634 | if (cfun->static_chain_decl != NULL_TREE) |
| 4635 | { |
| 4636 | varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl); |
| 4637 | |
| 4638 | for (p = chain_vi; p; p = p->next) |
| 4639 | make_constraint_from (p, nonlocal_id); |
| 4640 | } |
| 4641 | } |
| 4642 | |
| 4643 | /* Structure used to put solution bitmaps in a hashtable so they can |
| 4644 | be shared among variables with the same points-to set. */ |
| 4645 | |
| 4646 | typedef struct shared_bitmap_info |
| 4647 | { |
| 4648 | bitmap pt_vars; |
| 4649 | hashval_t hashcode; |
| 4650 | } *shared_bitmap_info_t; |
| 4651 | typedef const struct shared_bitmap_info *const_shared_bitmap_info_t; |
| 4652 | |
| 4653 | static htab_t shared_bitmap_table; |
| 4654 | |
| 4655 | /* Hash function for a shared_bitmap_info_t */ |
| 4656 | |
| 4657 | static hashval_t |
| 4658 | shared_bitmap_hash (const void *p) |
| 4659 | { |
| 4660 | const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p; |
| 4661 | return bi->hashcode; |
| 4662 | } |
| 4663 | |
| 4664 | /* Equality function for two shared_bitmap_info_t's. */ |
| 4665 | |
| 4666 | static int |
| 4667 | shared_bitmap_eq (const void *p1, const void *p2) |
| 4668 | { |
| 4669 | const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1; |
| 4670 | const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2; |
| 4671 | return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars); |
| 4672 | } |
| 4673 | |
| 4674 | /* Lookup a bitmap in the shared bitmap hashtable, and return an already |
| 4675 | existing instance if there is one, NULL otherwise. */ |
| 4676 | |
| 4677 | static bitmap |
| 4678 | shared_bitmap_lookup (bitmap pt_vars) |
| 4679 | { |
| 4680 | void **slot; |
| 4681 | struct shared_bitmap_info sbi; |
| 4682 | |
| 4683 | sbi.pt_vars = pt_vars; |
| 4684 | sbi.hashcode = bitmap_hash (pt_vars); |
| 4685 | |
| 4686 | slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi, |
| 4687 | sbi.hashcode, NO_INSERT); |
| 4688 | if (!slot) |
| 4689 | return NULL; |
| 4690 | else |
| 4691 | return ((shared_bitmap_info_t) *slot)->pt_vars; |
| 4692 | } |
| 4693 | |
| 4694 | |
| 4695 | /* Add a bitmap to the shared bitmap hashtable. */ |
| 4696 | |
| 4697 | static void |
| 4698 | shared_bitmap_add (bitmap pt_vars) |
| 4699 | { |
| 4700 | void **slot; |
| 4701 | shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info); |
| 4702 | |
| 4703 | sbi->pt_vars = pt_vars; |
| 4704 | sbi->hashcode = bitmap_hash (pt_vars); |
| 4705 | |
| 4706 | slot = htab_find_slot_with_hash (shared_bitmap_table, sbi, |
| 4707 | sbi->hashcode, INSERT); |
| 4708 | gcc_assert (!*slot); |
| 4709 | *slot = (void *) sbi; |
| 4710 | } |
| 4711 | |
| 4712 | |
| 4713 | /* Set bits in INTO corresponding to the variable uids in solution set |
| 4714 | FROM, which came from variable PTR. |
| 4715 | For variables that are actually dereferenced, we also use type |
| 4716 | based alias analysis to prune the points-to sets. |
| 4717 | IS_DEREFED is true if PTR was directly dereferenced, which we use to |
| 4718 | help determine whether we are we are allowed to prune using TBAA. |
| 4719 | If NO_TBAA_PRUNING is true, we do not perform any TBAA pruning of |
| 4720 | the from set. Returns the number of pruned variables. */ |
| 4721 | |
| 4722 | static unsigned |
| 4723 | set_uids_in_ptset (tree ptr, bitmap into, bitmap from, bool is_derefed, |
| 4724 | bool no_tbaa_pruning) |
| 4725 | { |
| 4726 | unsigned int i; |
| 4727 | bitmap_iterator bi; |
| 4728 | unsigned pruned = 0; |
| 4729 | |
| 4730 | gcc_assert (POINTER_TYPE_P (TREE_TYPE (ptr))); |
| 4731 | |
| 4732 | EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi) |
| 4733 | { |
| 4734 | varinfo_t vi = get_varinfo (i); |
| 4735 | |
| 4736 | /* The only artificial variables that are allowed in a may-alias |
| 4737 | set are heap variables. */ |
| 4738 | if (vi->is_artificial_var && !vi->is_heap_var) |
| 4739 | continue; |
| 4740 | |
| 4741 | if (TREE_CODE (vi->decl) == VAR_DECL |
| 4742 | || TREE_CODE (vi->decl) == PARM_DECL |
| 4743 | || TREE_CODE (vi->decl) == RESULT_DECL) |
| 4744 | { |
| 4745 | /* Just add VI->DECL to the alias set. |
| 4746 | Don't type prune artificial vars or points-to sets |
| 4747 | for pointers that have not been dereferenced or with |
| 4748 | type-based pruning disabled. */ |
| 4749 | if (vi->is_artificial_var |
| 4750 | || !is_derefed |
| 4751 | || no_tbaa_pruning |
| 4752 | || vi->no_tbaa_pruning) |
| 4753 | bitmap_set_bit (into, DECL_UID (vi->decl)); |
| 4754 | else |
| 4755 | { |
| 4756 | alias_set_type var_alias_set, mem_alias_set; |
| 4757 | var_alias_set = get_alias_set (vi->decl); |
| 4758 | mem_alias_set = get_alias_set (TREE_TYPE (TREE_TYPE (ptr))); |
| 4759 | if (may_alias_p (SSA_NAME_VAR (ptr), mem_alias_set, |
| 4760 | vi->decl, var_alias_set, true)) |
| 4761 | bitmap_set_bit (into, DECL_UID (vi->decl)); |
| 4762 | else |
| 4763 | ++pruned; |
| 4764 | } |
| 4765 | } |
| 4766 | } |
| 4767 | |
| 4768 | return pruned; |
| 4769 | } |
| 4770 | |
| 4771 | |
| 4772 | static bool have_alias_info = false; |
| 4773 | |
| 4774 | /* Emit a note for the pointer initialization point DEF. */ |
| 4775 | |
| 4776 | static void |
| 4777 | emit_pointer_definition (tree ptr, bitmap visited) |
| 4778 | { |
| 4779 | gimple def = SSA_NAME_DEF_STMT (ptr); |
| 4780 | if (gimple_code (def) == GIMPLE_PHI) |
| 4781 | { |
| 4782 | use_operand_p argp; |
| 4783 | ssa_op_iter oi; |
| 4784 | |
| 4785 | FOR_EACH_PHI_ARG (argp, def, oi, SSA_OP_USE) |
| 4786 | { |
| 4787 | tree arg = USE_FROM_PTR (argp); |
| 4788 | if (TREE_CODE (arg) == SSA_NAME) |
| 4789 | { |
| 4790 | if (bitmap_set_bit (visited, SSA_NAME_VERSION (arg))) |
| 4791 | emit_pointer_definition (arg, visited); |
| 4792 | } |
| 4793 | else |
| 4794 | inform (0, "initialized from %qE", arg); |
| 4795 | } |
| 4796 | } |
| 4797 | else if (!gimple_nop_p (def)) |
| 4798 | inform (gimple_location (def), "initialized from here"); |
| 4799 | } |
| 4800 | |
| 4801 | /* Emit a strict aliasing warning for dereferencing the pointer PTR. */ |
| 4802 | |
| 4803 | static void |
| 4804 | emit_alias_warning (tree ptr) |
| 4805 | { |
| 4806 | gimple use; |
| 4807 | imm_use_iterator ui; |
| 4808 | bool warned = false; |
| 4809 | |
| 4810 | FOR_EACH_IMM_USE_STMT (use, ui, ptr) |
| 4811 | { |
| 4812 | tree deref = NULL_TREE; |
| 4813 | |
| 4814 | if (gimple_has_lhs (use)) |
| 4815 | { |
| 4816 | tree lhs = get_base_address (gimple_get_lhs (use)); |
| 4817 | if (lhs |
| 4818 | && INDIRECT_REF_P (lhs) |
| 4819 | && TREE_OPERAND (lhs, 0) == ptr) |
| 4820 | deref = lhs; |
| 4821 | } |
| 4822 | if (gimple_assign_single_p (use)) |
| 4823 | { |
| 4824 | tree rhs = get_base_address (gimple_assign_rhs1 (use)); |
| 4825 | if (rhs |
| 4826 | && INDIRECT_REF_P (rhs) |
| 4827 | && TREE_OPERAND (rhs, 0) == ptr) |
| 4828 | deref = rhs; |
| 4829 | } |
| 4830 | else if (is_gimple_call (use)) |
| 4831 | { |
| 4832 | unsigned i; |
| 4833 | for (i = 0; i < gimple_call_num_args (use); ++i) |
| 4834 | { |
| 4835 | tree op = get_base_address (gimple_call_arg (use, i)); |
| 4836 | if (op |
| 4837 | && INDIRECT_REF_P (op) |
| 4838 | && TREE_OPERAND (op, 0) == ptr) |
| 4839 | deref = op; |
| 4840 | } |
| 4841 | } |
| 4842 | if (deref |
| 4843 | && !TREE_NO_WARNING (deref)) |
| 4844 | { |
| 4845 | TREE_NO_WARNING (deref) = 1; |
| 4846 | warned |= warning_at (gimple_location (use), OPT_Wstrict_aliasing, |
| 4847 | "dereferencing pointer %qD does break " |
| 4848 | "strict-aliasing rules", SSA_NAME_VAR (ptr)); |
| 4849 | } |
| 4850 | } |
| 4851 | if (warned) |
| 4852 | { |
| 4853 | bitmap visited = BITMAP_ALLOC (NULL); |
| 4854 | emit_pointer_definition (ptr, visited); |
| 4855 | BITMAP_FREE (visited); |
| 4856 | } |
| 4857 | } |
| 4858 | |
| 4859 | /* Given a pointer variable P, fill in its points-to set, or return |
| 4860 | false if we can't. |
| 4861 | Rather than return false for variables that point-to anything, we |
| 4862 | instead find the corresponding SMT, and merge in its aliases. In |
| 4863 | addition to these aliases, we also set the bits for the SMT's |
| 4864 | themselves and their subsets, as SMT's are still in use by |
| 4865 | non-SSA_NAME's, and pruning may eliminate every one of their |
| 4866 | aliases. In such a case, if we did not include the right set of |
| 4867 | SMT's in the points-to set of the variable, we'd end up with |
| 4868 | statements that do not conflict but should. */ |
| 4869 | |
| 4870 | bool |
| 4871 | find_what_p_points_to (tree p) |
| 4872 | { |
| 4873 | tree lookup_p = p; |
| 4874 | varinfo_t vi; |
| 4875 | |
| 4876 | if (!have_alias_info) |
| 4877 | return false; |
| 4878 | |
| 4879 | /* For parameters, get at the points-to set for the actual parm |
| 4880 | decl. */ |
| 4881 | if (TREE_CODE (p) == SSA_NAME |
| 4882 | && TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL |
| 4883 | && SSA_NAME_IS_DEFAULT_DEF (p)) |
| 4884 | lookup_p = SSA_NAME_VAR (p); |
| 4885 | |
| 4886 | vi = lookup_vi_for_tree (lookup_p); |
| 4887 | if (vi) |
| 4888 | { |
| 4889 | if (vi->is_artificial_var) |
| 4890 | return false; |
| 4891 | |
| 4892 | /* See if this is a field or a structure. */ |
| 4893 | if (vi->size != vi->fullsize) |
| 4894 | { |
| 4895 | /* Nothing currently asks about structure fields directly, |
| 4896 | but when they do, we need code here to hand back the |
| 4897 | points-to set. */ |
| 4898 | return false; |
| 4899 | } |
| 4900 | else |
| 4901 | { |
| 4902 | struct ptr_info_def *pi = get_ptr_info (p); |
| 4903 | unsigned int i, pruned; |
| 4904 | bitmap_iterator bi; |
| 4905 | bool was_pt_anything = false; |
| 4906 | bitmap finished_solution; |
| 4907 | bitmap result; |
| 4908 | |
| 4909 | if (!pi->memory_tag_needed) |
| 4910 | return false; |
| 4911 | |
| 4912 | /* This variable may have been collapsed, let's get the real |
| 4913 | variable. */ |
| 4914 | vi = get_varinfo (find (vi->id)); |
| 4915 | |
| 4916 | /* Translate artificial variables into SSA_NAME_PTR_INFO |
| 4917 | attributes. */ |
| 4918 | EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi) |
| 4919 | { |
| 4920 | varinfo_t vi = get_varinfo (i); |
| 4921 | |
| 4922 | if (vi->is_artificial_var) |
| 4923 | { |
| 4924 | /* FIXME. READONLY should be handled better so that |
| 4925 | flow insensitive aliasing can disregard writable |
| 4926 | aliases. */ |
| 4927 | if (vi->id == nothing_id) |
| 4928 | pi->pt_null = 1; |
| 4929 | else if (vi->id == anything_id |
| 4930 | || vi->id == nonlocal_id |
| 4931 | || vi->id == escaped_id |
| 4932 | || vi->id == callused_id) |
| 4933 | was_pt_anything = 1; |
| 4934 | else if (vi->id == readonly_id) |
| 4935 | was_pt_anything = 1; |
| 4936 | else if (vi->id == integer_id) |
| 4937 | was_pt_anything = 1; |
| 4938 | else if (vi->is_heap_var) |
| 4939 | pi->pt_global_mem = 1; |
| 4940 | } |
| 4941 | } |
| 4942 | |
| 4943 | /* Instead of doing extra work, simply do not create |
| 4944 | points-to information for pt_anything pointers. This |
| 4945 | will cause the operand scanner to fall back to the |
| 4946 | type-based SMT and its aliases. Which is the best |
| 4947 | we could do here for the points-to set as well. */ |
| 4948 | if (was_pt_anything) |
| 4949 | return false; |
| 4950 | |
| 4951 | /* Share the final set of variables when possible. */ |
| 4952 | finished_solution = BITMAP_GGC_ALLOC (); |
| 4953 | stats.points_to_sets_created++; |
| 4954 | |
| 4955 | pruned = set_uids_in_ptset (p, finished_solution, vi->solution, |
| 4956 | pi->is_dereferenced, |
| 4957 | vi->no_tbaa_pruning); |
| 4958 | result = shared_bitmap_lookup (finished_solution); |
| 4959 | |
| 4960 | if (!result) |
| 4961 | { |
| 4962 | shared_bitmap_add (finished_solution); |
| 4963 | pi->pt_vars = finished_solution; |
| 4964 | } |
| 4965 | else |
| 4966 | { |
| 4967 | pi->pt_vars = result; |
| 4968 | bitmap_clear (finished_solution); |
| 4969 | } |
| 4970 | |
| 4971 | if (bitmap_empty_p (pi->pt_vars)) |
| 4972 | { |
| 4973 | pi->pt_vars = NULL; |
| 4974 | if (pruned > 0 |
| 4975 | && !pi->pt_null |
| 4976 | && pi->is_dereferenced |
| 4977 | && warn_strict_aliasing > 0 |
| 4978 | && !SSA_NAME_IS_DEFAULT_DEF (p)) |
| 4979 | { |
| 4980 | if (dump_file && dump_flags & TDF_DETAILS) |
| 4981 | { |
| 4982 | fprintf (dump_file, "alias warning for "); |
| 4983 | print_generic_expr (dump_file, p, 0); |
| 4984 | fprintf (dump_file, "\n"); |
| 4985 | } |
| 4986 | emit_alias_warning (p); |
| 4987 | } |
| 4988 | } |
| 4989 | |
| 4990 | return true; |
| 4991 | } |
| 4992 | } |
| 4993 | |
| 4994 | return false; |
| 4995 | } |
| 4996 | |
| 4997 | /* Mark the ESCAPED solution as call clobbered. Returns false if |
| 4998 | pt_anything escaped which needs all locals that have their address |
| 4999 | taken marked call clobbered as well. */ |
| 5000 | |
| 5001 | bool |
| 5002 | clobber_what_escaped (void) |
| 5003 | { |
| 5004 | varinfo_t vi; |
| 5005 | unsigned int i; |
| 5006 | bitmap_iterator bi; |
| 5007 | |
| 5008 | if (!have_alias_info) |
| 5009 | return false; |
| 5010 | |
| 5011 | /* This variable may have been collapsed, let's get the real |
| 5012 | variable for escaped_id. */ |
| 5013 | vi = get_varinfo (find (escaped_id)); |
| 5014 | |
| 5015 | /* If call-used memory escapes we need to include it in the |
| 5016 | set of escaped variables. This can happen if a pure |
| 5017 | function returns a pointer and this pointer escapes. */ |
| 5018 | if (bitmap_bit_p (vi->solution, callused_id)) |
| 5019 | { |
| 5020 | varinfo_t cu_vi = get_varinfo (find (callused_id)); |
| 5021 | bitmap_ior_into (vi->solution, cu_vi->solution); |
| 5022 | } |
| 5023 | |
| 5024 | /* Mark variables in the solution call-clobbered. */ |
| 5025 | EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi) |
| 5026 | { |
| 5027 | varinfo_t vi = get_varinfo (i); |
| 5028 | |
| 5029 | if (vi->is_artificial_var) |
| 5030 | { |
| 5031 | /* nothing_id and readonly_id do not cause any |
| 5032 | call clobber ops. For anything_id and integer_id |
| 5033 | we need to clobber all addressable vars. */ |
| 5034 | if (vi->id == anything_id |
| 5035 | || vi->id == integer_id) |
| 5036 | return false; |
| 5037 | } |
| 5038 | |
| 5039 | /* Only artificial heap-vars are further interesting. */ |
| 5040 | if (vi->is_artificial_var && !vi->is_heap_var) |
| 5041 | continue; |
| 5042 | |
| 5043 | if ((TREE_CODE (vi->decl) == VAR_DECL |
| 5044 | || TREE_CODE (vi->decl) == PARM_DECL |
| 5045 | || TREE_CODE (vi->decl) == RESULT_DECL) |
| 5046 | && !unmodifiable_var_p (vi->decl)) |
| 5047 | mark_call_clobbered (vi->decl, ESCAPE_TO_CALL); |
| 5048 | } |
| 5049 | |
| 5050 | return true; |
| 5051 | } |
| 5052 | |
| 5053 | /* Compute the call-used variables. */ |
| 5054 | |
| 5055 | void |
| 5056 | compute_call_used_vars (void) |
| 5057 | { |
| 5058 | varinfo_t vi; |
| 5059 | unsigned int i; |
| 5060 | bitmap_iterator bi; |
| 5061 | bool has_anything_id = false; |
| 5062 | |
| 5063 | if (!have_alias_info) |
| 5064 | return; |
| 5065 | |
| 5066 | /* This variable may have been collapsed, let's get the real |
| 5067 | variable for escaped_id. */ |
| 5068 | vi = get_varinfo (find (callused_id)); |
| 5069 | |
| 5070 | /* Mark variables in the solution call-clobbered. */ |
| 5071 | EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi) |
| 5072 | { |
| 5073 | varinfo_t vi = get_varinfo (i); |
| 5074 | |
| 5075 | if (vi->is_artificial_var) |
| 5076 | { |
| 5077 | /* For anything_id and integer_id we need to make |
| 5078 | all local addressable vars call-used. */ |
| 5079 | if (vi->id == anything_id |
| 5080 | || vi->id == integer_id) |
| 5081 | has_anything_id = true; |
| 5082 | } |
| 5083 | |
| 5084 | /* Only artificial heap-vars are further interesting. */ |
| 5085 | if (vi->is_artificial_var && !vi->is_heap_var) |
| 5086 | continue; |
| 5087 | |
| 5088 | if ((TREE_CODE (vi->decl) == VAR_DECL |
| 5089 | || TREE_CODE (vi->decl) == PARM_DECL |
| 5090 | || TREE_CODE (vi->decl) == RESULT_DECL) |
| 5091 | && !unmodifiable_var_p (vi->decl)) |
| 5092 | bitmap_set_bit (gimple_call_used_vars (cfun), DECL_UID (vi->decl)); |
| 5093 | } |
| 5094 | |
| 5095 | /* If anything is call-used, add all addressable locals to the set. */ |
| 5096 | if (has_anything_id) |
| 5097 | bitmap_ior_into (gimple_call_used_vars (cfun), |
| 5098 | gimple_addressable_vars (cfun)); |
| 5099 | } |
| 5100 | |
| 5101 | |
| 5102 | /* Dump points-to information to OUTFILE. */ |
| 5103 | |
| 5104 | void |
| 5105 | dump_sa_points_to_info (FILE *outfile) |
| 5106 | { |
| 5107 | unsigned int i; |
| 5108 | |
| 5109 | fprintf (outfile, "\nPoints-to sets\n\n"); |
| 5110 | |
| 5111 | if (dump_flags & TDF_STATS) |
| 5112 | { |
| 5113 | fprintf (outfile, "Stats:\n"); |
| 5114 | fprintf (outfile, "Total vars: %d\n", stats.total_vars); |
| 5115 | fprintf (outfile, "Non-pointer vars: %d\n", |
| 5116 | stats.nonpointer_vars); |
| 5117 | fprintf (outfile, "Statically unified vars: %d\n", |
| 5118 | stats.unified_vars_static); |
| 5119 | fprintf (outfile, "Dynamically unified vars: %d\n", |
| 5120 | stats.unified_vars_dynamic); |
| 5121 | fprintf (outfile, "Iterations: %d\n", stats.iterations); |
| 5122 | fprintf (outfile, "Number of edges: %d\n", stats.num_edges); |
| 5123 | fprintf (outfile, "Number of implicit edges: %d\n", |
| 5124 | stats.num_implicit_edges); |
| 5125 | } |
| 5126 | |
| 5127 | for (i = 0; i < VEC_length (varinfo_t, varmap); i++) |
| 5128 | dump_solution_for_var (outfile, i); |
| 5129 | } |
| 5130 | |
| 5131 | |
| 5132 | /* Debug points-to information to stderr. */ |
| 5133 | |
| 5134 | void |
| 5135 | debug_sa_points_to_info (void) |
| 5136 | { |
| 5137 | dump_sa_points_to_info (stderr); |
| 5138 | } |
| 5139 | |
| 5140 | |
| 5141 | /* Initialize the always-existing constraint variables for NULL |
| 5142 | ANYTHING, READONLY, and INTEGER */ |
| 5143 | |
| 5144 | static void |
| 5145 | init_base_vars (void) |
| 5146 | { |
| 5147 | struct constraint_expr lhs, rhs; |
| 5148 | |
| 5149 | /* Create the NULL variable, used to represent that a variable points |
| 5150 | to NULL. */ |
| 5151 | nothing_tree = create_tmp_var_raw (void_type_node, "NULL"); |
| 5152 | var_nothing = new_var_info (nothing_tree, nothing_id, "NULL"); |
| 5153 | insert_vi_for_tree (nothing_tree, var_nothing); |
| 5154 | var_nothing->is_artificial_var = 1; |
| 5155 | var_nothing->offset = 0; |
| 5156 | var_nothing->size = ~0; |
| 5157 | var_nothing->fullsize = ~0; |
| 5158 | var_nothing->is_special_var = 1; |
| 5159 | VEC_safe_push (varinfo_t, heap, varmap, var_nothing); |
| 5160 | |
| 5161 | /* Create the ANYTHING variable, used to represent that a variable |
| 5162 | points to some unknown piece of memory. */ |
| 5163 | anything_tree = create_tmp_var_raw (void_type_node, "ANYTHING"); |
| 5164 | var_anything = new_var_info (anything_tree, anything_id, "ANYTHING"); |
| 5165 | insert_vi_for_tree (anything_tree, var_anything); |
| 5166 | var_anything->is_artificial_var = 1; |
| 5167 | var_anything->size = ~0; |
| 5168 | var_anything->offset = 0; |
| 5169 | var_anything->next = NULL; |
| 5170 | var_anything->fullsize = ~0; |
| 5171 | var_anything->is_special_var = 1; |
| 5172 | |
| 5173 | /* Anything points to anything. This makes deref constraints just |
| 5174 | work in the presence of linked list and other p = *p type loops, |
| 5175 | by saying that *ANYTHING = ANYTHING. */ |
| 5176 | VEC_safe_push (varinfo_t, heap, varmap, var_anything); |
| 5177 | lhs.type = SCALAR; |
| 5178 | lhs.var = anything_id; |
| 5179 | lhs.offset = 0; |
| 5180 | rhs.type = ADDRESSOF; |
| 5181 | rhs.var = anything_id; |
| 5182 | rhs.offset = 0; |
| 5183 | |
| 5184 | /* This specifically does not use process_constraint because |
| 5185 | process_constraint ignores all anything = anything constraints, since all |
| 5186 | but this one are redundant. */ |
| 5187 | VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs)); |
| 5188 | |
| 5189 | /* Create the READONLY variable, used to represent that a variable |
| 5190 | points to readonly memory. */ |
| 5191 | readonly_tree = create_tmp_var_raw (void_type_node, "READONLY"); |
| 5192 | var_readonly = new_var_info (readonly_tree, readonly_id, "READONLY"); |
| 5193 | var_readonly->is_artificial_var = 1; |
| 5194 | var_readonly->offset = 0; |
| 5195 | var_readonly->size = ~0; |
| 5196 | var_readonly->fullsize = ~0; |
| 5197 | var_readonly->next = NULL; |
| 5198 | var_readonly->is_special_var = 1; |
| 5199 | insert_vi_for_tree (readonly_tree, var_readonly); |
| 5200 | VEC_safe_push (varinfo_t, heap, varmap, var_readonly); |
| 5201 | |
| 5202 | /* readonly memory points to anything, in order to make deref |
| 5203 | easier. In reality, it points to anything the particular |
| 5204 | readonly variable can point to, but we don't track this |
| 5205 | separately. */ |
| 5206 | lhs.type = SCALAR; |
| 5207 | lhs.var = readonly_id; |
| 5208 | lhs.offset = 0; |
| 5209 | rhs.type = ADDRESSOF; |
| 5210 | rhs.var = readonly_id; /* FIXME */ |
| 5211 | rhs.offset = 0; |
| 5212 | process_constraint (new_constraint (lhs, rhs)); |
| 5213 | |
| 5214 | /* Create the ESCAPED variable, used to represent the set of escaped |
| 5215 | memory. */ |
| 5216 | escaped_tree = create_tmp_var_raw (void_type_node, "ESCAPED"); |
| 5217 | var_escaped = new_var_info (escaped_tree, escaped_id, "ESCAPED"); |
| 5218 | insert_vi_for_tree (escaped_tree, var_escaped); |
| 5219 | var_escaped->is_artificial_var = 1; |
| 5220 | var_escaped->offset = 0; |
| 5221 | var_escaped->size = ~0; |
| 5222 | var_escaped->fullsize = ~0; |
| 5223 | var_escaped->is_special_var = 0; |
| 5224 | VEC_safe_push (varinfo_t, heap, varmap, var_escaped); |
| 5225 | gcc_assert (VEC_index (varinfo_t, varmap, 3) == var_escaped); |
| 5226 | |
| 5227 | /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */ |
| 5228 | lhs.type = SCALAR; |
| 5229 | lhs.var = escaped_id; |
| 5230 | lhs.offset = 0; |
| 5231 | rhs.type = DEREF; |
| 5232 | rhs.var = escaped_id; |
| 5233 | rhs.offset = 0; |
| 5234 | process_constraint (new_constraint (lhs, rhs)); |
| 5235 | |
| 5236 | /* Create the NONLOCAL variable, used to represent the set of nonlocal |
| 5237 | memory. */ |
| 5238 | nonlocal_tree = create_tmp_var_raw (void_type_node, "NONLOCAL"); |
| 5239 | var_nonlocal = new_var_info (nonlocal_tree, nonlocal_id, "NONLOCAL"); |
| 5240 | insert_vi_for_tree (nonlocal_tree, var_nonlocal); |
| 5241 | var_nonlocal->is_artificial_var = 1; |
| 5242 | var_nonlocal->offset = 0; |
| 5243 | var_nonlocal->size = ~0; |
| 5244 | var_nonlocal->fullsize = ~0; |
| 5245 | var_nonlocal->is_special_var = 1; |
| 5246 | VEC_safe_push (varinfo_t, heap, varmap, var_nonlocal); |
| 5247 | |
| 5248 | /* Nonlocal memory points to escaped (which includes nonlocal), |
| 5249 | in order to make deref easier. */ |
| 5250 | lhs.type = SCALAR; |
| 5251 | lhs.var = nonlocal_id; |
| 5252 | lhs.offset = 0; |
| 5253 | rhs.type = ADDRESSOF; |
| 5254 | rhs.var = escaped_id; |
| 5255 | rhs.offset = 0; |
| 5256 | process_constraint (new_constraint (lhs, rhs)); |
| 5257 | |
| 5258 | /* Create the CALLUSED variable, used to represent the set of call-used |
| 5259 | memory. */ |
| 5260 | callused_tree = create_tmp_var_raw (void_type_node, "CALLUSED"); |
| 5261 | var_callused = new_var_info (callused_tree, callused_id, "CALLUSED"); |
| 5262 | insert_vi_for_tree (callused_tree, var_callused); |
| 5263 | var_callused->is_artificial_var = 1; |
| 5264 | var_callused->offset = 0; |
| 5265 | var_callused->size = ~0; |
| 5266 | var_callused->fullsize = ~0; |
| 5267 | var_callused->is_special_var = 0; |
| 5268 | VEC_safe_push (varinfo_t, heap, varmap, var_callused); |
| 5269 | |
| 5270 | /* CALLUSED = *CALLUSED, because call-used is may-deref'd at calls, etc. */ |
| 5271 | lhs.type = SCALAR; |
| 5272 | lhs.var = callused_id; |
| 5273 | lhs.offset = 0; |
| 5274 | rhs.type = DEREF; |
| 5275 | rhs.var = callused_id; |
| 5276 | rhs.offset = 0; |
| 5277 | process_constraint (new_constraint (lhs, rhs)); |
| 5278 | |
| 5279 | /* Create the STOREDANYTHING variable, used to represent the set of |
| 5280 | variables stored to *ANYTHING. */ |
| 5281 | storedanything_tree = create_tmp_var_raw (ptr_type_node, "STOREDANYTHING"); |
| 5282 | var_storedanything = new_var_info (storedanything_tree, storedanything_id, |
| 5283 | "STOREDANYTHING"); |
| 5284 | insert_vi_for_tree (storedanything_tree, var_storedanything); |
| 5285 | var_storedanything->is_artificial_var = 1; |
| 5286 | var_storedanything->offset = 0; |
| 5287 | var_storedanything->size = ~0; |
| 5288 | var_storedanything->fullsize = ~0; |
| 5289 | var_storedanything->is_special_var = 0; |
| 5290 | VEC_safe_push (varinfo_t, heap, varmap, var_storedanything); |
| 5291 | |
| 5292 | /* Create the INTEGER variable, used to represent that a variable points |
| 5293 | to an INTEGER. */ |
| 5294 | integer_tree = create_tmp_var_raw (void_type_node, "INTEGER"); |
| 5295 | var_integer = new_var_info (integer_tree, integer_id, "INTEGER"); |
| 5296 | insert_vi_for_tree (integer_tree, var_integer); |
| 5297 | var_integer->is_artificial_var = 1; |
| 5298 | var_integer->size = ~0; |
| 5299 | var_integer->fullsize = ~0; |
| 5300 | var_integer->offset = 0; |
| 5301 | var_integer->next = NULL; |
| 5302 | var_integer->is_special_var = 1; |
| 5303 | VEC_safe_push (varinfo_t, heap, varmap, var_integer); |
| 5304 | |
| 5305 | /* INTEGER = ANYTHING, because we don't know where a dereference of |
| 5306 | a random integer will point to. */ |
| 5307 | lhs.type = SCALAR; |
| 5308 | lhs.var = integer_id; |
| 5309 | lhs.offset = 0; |
| 5310 | rhs.type = ADDRESSOF; |
| 5311 | rhs.var = anything_id; |
| 5312 | rhs.offset = 0; |
| 5313 | process_constraint (new_constraint (lhs, rhs)); |
| 5314 | |
| 5315 | /* *ESCAPED = &ESCAPED. This is true because we have to assume |
| 5316 | everything pointed to by escaped can also point to escaped. */ |
| 5317 | lhs.type = DEREF; |
| 5318 | lhs.var = escaped_id; |
| 5319 | lhs.offset = 0; |
| 5320 | rhs.type = ADDRESSOF; |
| 5321 | rhs.var = escaped_id; |
| 5322 | rhs.offset = 0; |
| 5323 | process_constraint (new_constraint (lhs, rhs)); |
| 5324 | |
| 5325 | /* *ESCAPED = &NONLOCAL. This is true because we have to assume |
| 5326 | everything pointed to by escaped can also point to nonlocal. */ |
| 5327 | lhs.type = DEREF; |
| 5328 | lhs.var = escaped_id; |
| 5329 | lhs.offset = 0; |
| 5330 | rhs.type = ADDRESSOF; |
| 5331 | rhs.var = nonlocal_id; |
| 5332 | rhs.offset = 0; |
| 5333 | process_constraint (new_constraint (lhs, rhs)); |
| 5334 | } |
| 5335 | |
| 5336 | /* Initialize things necessary to perform PTA */ |
| 5337 | |
| 5338 | static void |
| 5339 | init_alias_vars (void) |
| 5340 | { |
| 5341 | use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1); |
| 5342 | |
| 5343 | bitmap_obstack_initialize (&pta_obstack); |
| 5344 | bitmap_obstack_initialize (&oldpta_obstack); |
| 5345 | bitmap_obstack_initialize (&predbitmap_obstack); |
| 5346 | |
| 5347 | constraint_pool = create_alloc_pool ("Constraint pool", |
| 5348 | sizeof (struct constraint), 30); |
| 5349 | variable_info_pool = create_alloc_pool ("Variable info pool", |
| 5350 | sizeof (struct variable_info), 30); |
| 5351 | constraints = VEC_alloc (constraint_t, heap, 8); |
| 5352 | varmap = VEC_alloc (varinfo_t, heap, 8); |
| 5353 | vi_for_tree = pointer_map_create (); |
| 5354 | |
| 5355 | memset (&stats, 0, sizeof (stats)); |
| 5356 | shared_bitmap_table = htab_create (511, shared_bitmap_hash, |
| 5357 | shared_bitmap_eq, free); |
| 5358 | init_base_vars (); |
| 5359 | } |
| 5360 | |
| 5361 | /* Remove the REF and ADDRESS edges from GRAPH, as well as all the |
| 5362 | predecessor edges. */ |
| 5363 | |
| 5364 | static void |
| 5365 | remove_preds_and_fake_succs (constraint_graph_t graph) |
| 5366 | { |
| 5367 | unsigned int i; |
| 5368 | |
| 5369 | /* Clear the implicit ref and address nodes from the successor |
| 5370 | lists. */ |
| 5371 | for (i = 0; i < FIRST_REF_NODE; i++) |
| 5372 | { |
| 5373 | if (graph->succs[i]) |
| 5374 | bitmap_clear_range (graph->succs[i], FIRST_REF_NODE, |
| 5375 | FIRST_REF_NODE * 2); |
| 5376 | } |
| 5377 | |
| 5378 | /* Free the successor list for the non-ref nodes. */ |
| 5379 | for (i = FIRST_REF_NODE; i < graph->size; i++) |
| 5380 | { |
| 5381 | if (graph->succs[i]) |
| 5382 | BITMAP_FREE (graph->succs[i]); |
| 5383 | } |
| 5384 | |
| 5385 | /* Now reallocate the size of the successor list as, and blow away |
| 5386 | the predecessor bitmaps. */ |
| 5387 | graph->size = VEC_length (varinfo_t, varmap); |
| 5388 | graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size); |
| 5389 | |
| 5390 | free (graph->implicit_preds); |
| 5391 | graph->implicit_preds = NULL; |
| 5392 | free (graph->preds); |
| 5393 | graph->preds = NULL; |
| 5394 | bitmap_obstack_release (&predbitmap_obstack); |
| 5395 | } |
| 5396 | |
| 5397 | /* Compute the set of variables we can't TBAA prune. */ |
| 5398 | |
| 5399 | static void |
| 5400 | compute_tbaa_pruning (void) |
| 5401 | { |
| 5402 | unsigned int size = VEC_length (varinfo_t, varmap); |
| 5403 | unsigned int i; |
| 5404 | bool any; |
| 5405 | |
| 5406 | changed_count = 0; |
| 5407 | changed = sbitmap_alloc (size); |
| 5408 | sbitmap_zero (changed); |
| 5409 | |
| 5410 | /* Mark all initial no_tbaa_pruning nodes as changed. */ |
| 5411 | any = false; |
| 5412 | for (i = 0; i < size; ++i) |
| 5413 | { |
| 5414 | varinfo_t ivi = get_varinfo (i); |
| 5415 | |
| 5416 | if (find (i) == i && ivi->no_tbaa_pruning) |
| 5417 | { |
| 5418 | any = true; |
| 5419 | if ((graph->succs[i] && !bitmap_empty_p (graph->succs[i])) |
| 5420 | || VEC_length (constraint_t, graph->complex[i]) > 0) |
| 5421 | { |
| 5422 | SET_BIT (changed, i); |
| 5423 | ++changed_count; |
| 5424 | } |
| 5425 | } |
| 5426 | } |
| 5427 | |
| 5428 | while (changed_count > 0) |
| 5429 | { |
| 5430 | struct topo_info *ti = init_topo_info (); |
| 5431 | ++stats.iterations; |
| 5432 | |
| 5433 | compute_topo_order (graph, ti); |
| 5434 | |
| 5435 | while (VEC_length (unsigned, ti->topo_order) != 0) |
| 5436 | { |
| 5437 | bitmap_iterator bi; |
| 5438 | |
| 5439 | i = VEC_pop (unsigned, ti->topo_order); |
| 5440 | |
| 5441 | /* If this variable is not a representative, skip it. */ |
| 5442 | if (find (i) != i) |
| 5443 | continue; |
| 5444 | |
| 5445 | /* If the node has changed, we need to process the complex |
| 5446 | constraints and outgoing edges again. */ |
| 5447 | if (TEST_BIT (changed, i)) |
| 5448 | { |
| 5449 | unsigned int j; |
| 5450 | constraint_t c; |
| 5451 | VEC(constraint_t,heap) *complex = graph->complex[i]; |
| 5452 | |
| 5453 | RESET_BIT (changed, i); |
| 5454 | --changed_count; |
| 5455 | |
| 5456 | /* Process the complex copy constraints. */ |
| 5457 | for (j = 0; VEC_iterate (constraint_t, complex, j, c); ++j) |
| 5458 | { |
| 5459 | if (c->lhs.type == SCALAR && c->rhs.type == SCALAR) |
| 5460 | { |
| 5461 | varinfo_t lhsvi = get_varinfo (find (c->lhs.var)); |
| 5462 | |
| 5463 | if (!lhsvi->no_tbaa_pruning) |
| 5464 | { |
| 5465 | lhsvi->no_tbaa_pruning = true; |
| 5466 | if (!TEST_BIT (changed, lhsvi->id)) |
| 5467 | { |
| 5468 | SET_BIT (changed, lhsvi->id); |
| 5469 | ++changed_count; |
| 5470 | } |
| 5471 | } |
| 5472 | } |
| 5473 | } |
| 5474 | |
| 5475 | /* Propagate to all successors. */ |
| 5476 | EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i], 0, j, bi) |
| 5477 | { |
| 5478 | unsigned int to = find (j); |
| 5479 | varinfo_t tovi = get_varinfo (to); |
| 5480 | |
| 5481 | /* Don't propagate to ourselves. */ |
| 5482 | if (to == i) |
| 5483 | continue; |
| 5484 | |
| 5485 | if (!tovi->no_tbaa_pruning) |
| 5486 | { |
| 5487 | tovi->no_tbaa_pruning = true; |
| 5488 | if (!TEST_BIT (changed, to)) |
| 5489 | { |
| 5490 | SET_BIT (changed, to); |
| 5491 | ++changed_count; |
| 5492 | } |
| 5493 | } |
| 5494 | } |
| 5495 | } |
| 5496 | } |
| 5497 | |
| 5498 | free_topo_info (ti); |
| 5499 | } |
| 5500 | |
| 5501 | sbitmap_free (changed); |
| 5502 | |
| 5503 | if (any) |
| 5504 | { |
| 5505 | for (i = 0; i < size; ++i) |
| 5506 | { |
| 5507 | varinfo_t ivi = get_varinfo (i); |
| 5508 | varinfo_t ivip = get_varinfo (find (i)); |
| 5509 | |
| 5510 | if (ivip->no_tbaa_pruning) |
| 5511 | { |
| 5512 | tree var = ivi->decl; |
| 5513 | |
| 5514 | if (TREE_CODE (var) == SSA_NAME) |
| 5515 | var = SSA_NAME_VAR (var); |
| 5516 | |
| 5517 | if (POINTER_TYPE_P (TREE_TYPE (var))) |
| 5518 | { |
| 5519 | DECL_NO_TBAA_P (var) = 1; |
| 5520 | |
| 5521 | /* Tell the RTL layer that this pointer can alias |
| 5522 | anything. */ |
| 5523 | DECL_POINTER_ALIAS_SET (var) = 0; |
| 5524 | } |
| 5525 | } |
| 5526 | } |
| 5527 | } |
| 5528 | } |
| 5529 | |
| 5530 | /* Create points-to sets for the current function. See the comments |
| 5531 | at the start of the file for an algorithmic overview. */ |
| 5532 | |
| 5533 | void |
| 5534 | compute_points_to_sets (void) |
| 5535 | { |
| 5536 | struct scc_info *si; |
| 5537 | basic_block bb; |
| 5538 | |
| 5539 | timevar_push (TV_TREE_PTA); |
| 5540 | |
| 5541 | init_alias_vars (); |
| 5542 | init_alias_heapvars (); |
| 5543 | |
| 5544 | intra_create_variable_infos (); |
| 5545 | |
| 5546 | /* Now walk all statements and derive aliases. */ |
| 5547 | FOR_EACH_BB (bb) |
| 5548 | { |
| 5549 | gimple_stmt_iterator gsi; |
| 5550 | |
| 5551 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 5552 | { |
| 5553 | gimple phi = gsi_stmt (gsi); |
| 5554 | |
| 5555 | if (is_gimple_reg (gimple_phi_result (phi))) |
| 5556 | find_func_aliases (phi); |
| 5557 | } |
| 5558 | |
| 5559 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 5560 | find_func_aliases (gsi_stmt (gsi)); |
| 5561 | } |
| 5562 | |
| 5563 | |
| 5564 | if (dump_file) |
| 5565 | { |
| 5566 | fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n"); |
| 5567 | dump_constraints (dump_file); |
| 5568 | } |
| 5569 | |
| 5570 | if (dump_file) |
| 5571 | fprintf (dump_file, |
| 5572 | "\nCollapsing static cycles and doing variable " |
| 5573 | "substitution\n"); |
| 5574 | |
| 5575 | init_graph (VEC_length (varinfo_t, varmap) * 2); |
| 5576 | |
| 5577 | if (dump_file) |
| 5578 | fprintf (dump_file, "Building predecessor graph\n"); |
| 5579 | build_pred_graph (); |
| 5580 | |
| 5581 | if (dump_file) |
| 5582 | fprintf (dump_file, "Detecting pointer and location " |
| 5583 | "equivalences\n"); |
| 5584 | si = perform_var_substitution (graph); |
| 5585 | |
| 5586 | if (dump_file) |
| 5587 | fprintf (dump_file, "Rewriting constraints and unifying " |
| 5588 | "variables\n"); |
| 5589 | rewrite_constraints (graph, si); |
| 5590 | |
| 5591 | build_succ_graph (); |
| 5592 | free_var_substitution_info (si); |
| 5593 | |
| 5594 | if (dump_file && (dump_flags & TDF_GRAPH)) |
| 5595 | dump_constraint_graph (dump_file); |
| 5596 | |
| 5597 | move_complex_constraints (graph); |
| 5598 | |
| 5599 | if (dump_file) |
| 5600 | fprintf (dump_file, "Uniting pointer but not location equivalent " |
| 5601 | "variables\n"); |
| 5602 | unite_pointer_equivalences (graph); |
| 5603 | |
| 5604 | if (dump_file) |
| 5605 | fprintf (dump_file, "Finding indirect cycles\n"); |
| 5606 | find_indirect_cycles (graph); |
| 5607 | |
| 5608 | /* Implicit nodes and predecessors are no longer necessary at this |
| 5609 | point. */ |
| 5610 | remove_preds_and_fake_succs (graph); |
| 5611 | |
| 5612 | if (dump_file) |
| 5613 | fprintf (dump_file, "Solving graph\n"); |
| 5614 | |
| 5615 | solve_graph (graph); |
| 5616 | |
| 5617 | compute_tbaa_pruning (); |
| 5618 | |
| 5619 | if (dump_file) |
| 5620 | dump_sa_points_to_info (dump_file); |
| 5621 | |
| 5622 | have_alias_info = true; |
| 5623 | |
| 5624 | timevar_pop (TV_TREE_PTA); |
| 5625 | } |
| 5626 | |
| 5627 | |
| 5628 | /* Delete created points-to sets. */ |
| 5629 | |
| 5630 | void |
| 5631 | delete_points_to_sets (void) |
| 5632 | { |
| 5633 | unsigned int i; |
| 5634 | |
| 5635 | htab_delete (shared_bitmap_table); |
| 5636 | if (dump_file && (dump_flags & TDF_STATS)) |
| 5637 | fprintf (dump_file, "Points to sets created:%d\n", |
| 5638 | stats.points_to_sets_created); |
| 5639 | |
| 5640 | pointer_map_destroy (vi_for_tree); |
| 5641 | bitmap_obstack_release (&pta_obstack); |
| 5642 | VEC_free (constraint_t, heap, constraints); |
| 5643 | |
| 5644 | for (i = 0; i < graph->size; i++) |
| 5645 | VEC_free (constraint_t, heap, graph->complex[i]); |
| 5646 | free (graph->complex); |
| 5647 | |
| 5648 | free (graph->rep); |
| 5649 | free (graph->succs); |
| 5650 | free (graph->pe); |
| 5651 | free (graph->pe_rep); |
| 5652 | free (graph->indirect_cycles); |
| 5653 | free (graph); |
| 5654 | |
| 5655 | VEC_free (varinfo_t, heap, varmap); |
| 5656 | free_alloc_pool (variable_info_pool); |
| 5657 | free_alloc_pool (constraint_pool); |
| 5658 | have_alias_info = false; |
| 5659 | } |
| 5660 | |
| 5661 | /* Return true if we should execute IPA PTA. */ |
| 5662 | static bool |
| 5663 | gate_ipa_pta (void) |
| 5664 | { |
| 5665 | return (flag_ipa_pta |
| 5666 | /* Don't bother doing anything if the program has errors. */ |
| 5667 | && !(errorcount || sorrycount)); |
| 5668 | } |
| 5669 | |
| 5670 | /* Execute the driver for IPA PTA. */ |
| 5671 | static unsigned int |
| 5672 | ipa_pta_execute (void) |
| 5673 | { |
| 5674 | struct cgraph_node *node; |
| 5675 | struct scc_info *si; |
| 5676 | |
| 5677 | in_ipa_mode = 1; |
| 5678 | init_alias_heapvars (); |
| 5679 | init_alias_vars (); |
| 5680 | |
| 5681 | for (node = cgraph_nodes; node; node = node->next) |
| 5682 | { |
| 5683 | if (!node->analyzed || cgraph_is_master_clone (node)) |
| 5684 | { |
| 5685 | unsigned int varid; |
| 5686 | |
| 5687 | varid = create_function_info_for (node->decl, |
| 5688 | cgraph_node_name (node)); |
| 5689 | if (node->local.externally_visible) |
| 5690 | { |
| 5691 | varinfo_t fi = get_varinfo (varid); |
| 5692 | for (; fi; fi = fi->next) |
| 5693 | make_constraint_from (fi, anything_id); |
| 5694 | } |
| 5695 | } |
| 5696 | } |
| 5697 | for (node = cgraph_nodes; node; node = node->next) |
| 5698 | { |
| 5699 | if (node->analyzed && cgraph_is_master_clone (node)) |
| 5700 | { |
| 5701 | struct function *func = DECL_STRUCT_FUNCTION (node->decl); |
| 5702 | basic_block bb; |
| 5703 | tree old_func_decl = current_function_decl; |
| 5704 | if (dump_file) |
| 5705 | fprintf (dump_file, |
| 5706 | "Generating constraints for %s\n", |
| 5707 | cgraph_node_name (node)); |
| 5708 | push_cfun (func); |
| 5709 | current_function_decl = node->decl; |
| 5710 | |
| 5711 | FOR_EACH_BB_FN (bb, func) |
| 5712 | { |
| 5713 | gimple_stmt_iterator gsi; |
| 5714 | |
| 5715 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
| 5716 | gsi_next (&gsi)) |
| 5717 | { |
| 5718 | gimple phi = gsi_stmt (gsi); |
| 5719 | |
| 5720 | if (is_gimple_reg (gimple_phi_result (phi))) |
| 5721 | find_func_aliases (phi); |
| 5722 | } |
| 5723 | |
| 5724 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 5725 | find_func_aliases (gsi_stmt (gsi)); |
| 5726 | } |
| 5727 | current_function_decl = old_func_decl; |
| 5728 | pop_cfun (); |
| 5729 | } |
| 5730 | else |
| 5731 | { |
| 5732 | /* Make point to anything. */ |
| 5733 | } |
| 5734 | } |
| 5735 | |
| 5736 | if (dump_file) |
| 5737 | { |
| 5738 | fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n"); |
| 5739 | dump_constraints (dump_file); |
| 5740 | } |
| 5741 | |
| 5742 | if (dump_file) |
| 5743 | fprintf (dump_file, |
| 5744 | "\nCollapsing static cycles and doing variable " |
| 5745 | "substitution:\n"); |
| 5746 | |
| 5747 | init_graph (VEC_length (varinfo_t, varmap) * 2); |
| 5748 | build_pred_graph (); |
| 5749 | si = perform_var_substitution (graph); |
| 5750 | rewrite_constraints (graph, si); |
| 5751 | |
| 5752 | build_succ_graph (); |
| 5753 | free_var_substitution_info (si); |
| 5754 | move_complex_constraints (graph); |
| 5755 | unite_pointer_equivalences (graph); |
| 5756 | find_indirect_cycles (graph); |
| 5757 | |
| 5758 | /* Implicit nodes and predecessors are no longer necessary at this |
| 5759 | point. */ |
| 5760 | remove_preds_and_fake_succs (graph); |
| 5761 | |
| 5762 | if (dump_file) |
| 5763 | fprintf (dump_file, "\nSolving graph\n"); |
| 5764 | |
| 5765 | solve_graph (graph); |
| 5766 | |
| 5767 | if (dump_file) |
| 5768 | dump_sa_points_to_info (dump_file); |
| 5769 | |
| 5770 | in_ipa_mode = 0; |
| 5771 | delete_alias_heapvars (); |
| 5772 | delete_points_to_sets (); |
| 5773 | return 0; |
| 5774 | } |
| 5775 | |
| 5776 | struct simple_ipa_opt_pass pass_ipa_pta = |
| 5777 | { |
| 5778 | { |
| 5779 | SIMPLE_IPA_PASS, |
| 5780 | "pta", /* name */ |
| 5781 | gate_ipa_pta, /* gate */ |
| 5782 | ipa_pta_execute, /* execute */ |
| 5783 | NULL, /* sub */ |
| 5784 | NULL, /* next */ |
| 5785 | 0, /* static_pass_number */ |
| 5786 | TV_IPA_PTA, /* tv_id */ |
| 5787 | 0, /* properties_required */ |
| 5788 | 0, /* properties_provided */ |
| 5789 | 0, /* properties_destroyed */ |
| 5790 | 0, /* todo_flags_start */ |
| 5791 | TODO_update_ssa /* todo_flags_finish */ |
| 5792 | } |
| 5793 | }; |
| 5794 | |
| 5795 | /* Initialize the heapvar for statement mapping. */ |
| 5796 | void |
| 5797 | init_alias_heapvars (void) |
| 5798 | { |
| 5799 | if (!heapvar_for_stmt) |
| 5800 | heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, tree_map_eq, |
| 5801 | NULL); |
| 5802 | } |
| 5803 | |
| 5804 | void |
| 5805 | delete_alias_heapvars (void) |
| 5806 | { |
| 5807 | htab_delete (heapvar_for_stmt); |
| 5808 | heapvar_for_stmt = NULL; |
| 5809 | } |
| 5810 | |
| 5811 | #include "gt-tree-ssa-structalias.h" |