1 /* Tree based points-to analysis 2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011 3 Free Software Foundation, Inc. 4 Contributed by Daniel Berlin <dberlin@dberlin.org> 5 6 This file is part of GCC. 7 8 GCC is free software; you can redistribute it and/or modify 9 under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or 11 (at your option) any later version. 12 13 GCC is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with GCC; see the file COPYING3. If not see 20 <http://www.gnu.org/licenses/>. */ 21 22 #include "config.h" 23 #include "system.h" 24 #include "coretypes.h" 25 #include "tm.h" 26 #include "ggc.h" 27 #include "obstack.h" 28 #include "bitmap.h" 29 #include "flags.h" 30 #include "basic-block.h" 31 #include "output.h" 32 #include "tree.h" 33 #include "tree-flow.h" 34 #include "tree-inline.h" 35 #include "diagnostic-core.h" 36 #include "gimple.h" 37 #include "hashtab.h" 38 #include "function.h" 39 #include "cgraph.h" 40 #include "tree-pass.h" 41 #include "timevar.h" 42 #include "alloc-pool.h" 43 #include "splay-tree.h" 44 #include "params.h" 45 #include "cgraph.h" 46 #include "alias.h" 47 #include "pointer-set.h" 48 49 /* The idea behind this analyzer is to generate set constraints from the 50 program, then solve the resulting constraints in order to generate the 51 points-to sets. 52 53 Set constraints are a way of modeling program analysis problems that 54 involve sets. They consist of an inclusion constraint language, 55 describing the variables (each variable is a set) and operations that 56 are involved on the variables, and a set of rules that derive facts 57 from these operations. To solve a system of set constraints, you derive 58 all possible facts under the rules, which gives you the correct sets 59 as a consequence. 60 61 See "Efficient Field-sensitive pointer analysis for C" by "David 62 J. Pearce and Paul H. J. Kelly and Chris Hankin, at 63 http://citeseer.ist.psu.edu/pearce04efficient.html 64 65 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines 66 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at 67 http://citeseer.ist.psu.edu/heintze01ultrafast.html 68 69 There are three types of real constraint expressions, DEREF, 70 ADDRESSOF, and SCALAR. Each constraint expression consists 71 of a constraint type, a variable, and an offset. 72 73 SCALAR is a constraint expression type used to represent x, whether 74 it appears on the LHS or the RHS of a statement. 75 DEREF is a constraint expression type used to represent *x, whether 76 it appears on the LHS or the RHS of a statement. 77 ADDRESSOF is a constraint expression used to represent &x, whether 78 it appears on the LHS or the RHS of a statement. 79 80 Each pointer variable in the program is assigned an integer id, and 81 each field of a structure variable is assigned an integer id as well. 82 83 Structure variables are linked to their list of fields through a "next 84 field" in each variable that points to the next field in offset 85 order. 86 Each variable for a structure field has 87 88 1. "size", that tells the size in bits of that field. 89 2. "fullsize, that tells the size in bits of the entire structure. 90 3. "offset", that tells the offset in bits from the beginning of the 91 structure to this field. 92 93 Thus, 94 struct f 95 { 96 int a; 97 int b; 98 } foo; 99 int *bar; 100 101 looks like 102 103 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b 104 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL 105 bar -> id 3, size 32, offset 0, fullsize 32, next NULL 106 107 108 In order to solve the system of set constraints, the following is 109 done: 110 111 1. Each constraint variable x has a solution set associated with it, 112 Sol(x). 113 114 2. Constraints are separated into direct, copy, and complex. 115 Direct constraints are ADDRESSOF constraints that require no extra 116 processing, such as P = &Q 117 Copy constraints are those of the form P = Q. 118 Complex constraints are all the constraints involving dereferences 119 and offsets (including offsetted copies). 120 121 3. All direct constraints of the form P = &Q are processed, such 122 that Q is added to Sol(P) 123 124 4. All complex constraints for a given constraint variable are stored in a 125 linked list attached to that variable's node. 126 127 5. A directed graph is built out of the copy constraints. Each 128 constraint variable is a node in the graph, and an edge from 129 Q to P is added for each copy constraint of the form P = Q 130 131 6. The graph is then walked, and solution sets are 132 propagated along the copy edges, such that an edge from Q to P 133 causes Sol(P) <- Sol(P) union Sol(Q). 134 135 7. As we visit each node, all complex constraints associated with 136 that node are processed by adding appropriate copy edges to the graph, or the 137 appropriate variables to the solution set. 138 139 8. The process of walking the graph is iterated until no solution 140 sets change. 141 142 Prior to walking the graph in steps 6 and 7, We perform static 143 cycle elimination on the constraint graph, as well 144 as off-line variable substitution. 145 146 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted 147 on and turned into anything), but isn't. You can just see what offset 148 inside the pointed-to struct it's going to access. 149 150 TODO: Constant bounded arrays can be handled as if they were structs of the 151 same number of elements. 152 153 TODO: Modeling heap and incoming pointers becomes much better if we 154 add fields to them as we discover them, which we could do. 155 156 TODO: We could handle unions, but to be honest, it's probably not 157 worth the pain or slowdown. */ 158 159 /* IPA-PTA optimizations possible. 160 161 When the indirect function called is ANYTHING we can add disambiguation 162 based on the function signatures (or simply the parameter count which 163 is the varinfo size). We also do not need to consider functions that 164 do not have their address taken. 165 166 The is_global_var bit which marks escape points is overly conservative 167 in IPA mode. Split it to is_escape_point and is_global_var - only 168 externally visible globals are escape points in IPA mode. This is 169 also needed to fix the pt_solution_includes_global predicate 170 (and thus ptr_deref_may_alias_global_p). 171 172 The way we introduce DECL_PT_UID to avoid fixing up all points-to 173 sets in the translation unit when we copy a DECL during inlining 174 pessimizes precision. The advantage is that the DECL_PT_UID keeps 175 compile-time and memory usage overhead low - the points-to sets 176 do not grow or get unshared as they would during a fixup phase. 177 An alternative solution is to delay IPA PTA until after all 178 inlining transformations have been applied. 179 180 The way we propagate clobber/use information isn't optimized. 181 It should use a new complex constraint that properly filters 182 out local variables of the callee (though that would make 183 the sets invalid after inlining). OTOH we might as well 184 admit defeat to WHOPR and simply do all the clobber/use analysis 185 and propagation after PTA finished but before we threw away 186 points-to information for memory variables. WHOPR and PTA 187 do not play along well anyway - the whole constraint solving 188 would need to be done in WPA phase and it will be very interesting 189 to apply the results to local SSA names during LTRANS phase. 190 191 We probably should compute a per-function unit-ESCAPE solution 192 propagating it simply like the clobber / uses solutions. The 193 solution can go alongside the non-IPA espaced solution and be 194 used to query which vars escape the unit through a function. 195 196 We never put function decls in points-to sets so we do not 197 keep the set of called functions for indirect calls. 198 199 And probably more. */ 200 201 static bool use_field_sensitive = true; 202 static int in_ipa_mode = 0; 203 204 /* Used for predecessor bitmaps. */ 205 static bitmap_obstack predbitmap_obstack; 206 207 /* Used for points-to sets. */ 208 static bitmap_obstack pta_obstack; 209 210 /* Used for oldsolution members of variables. */ 211 static bitmap_obstack oldpta_obstack; 212 213 /* Used for per-solver-iteration bitmaps. */ 214 static bitmap_obstack iteration_obstack; 215 216 static unsigned int create_variable_info_for (tree, const char *); 217 typedef struct constraint_graph *constraint_graph_t; 218 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool); 219 220 struct constraint; 221 typedef struct constraint *constraint_t; 222 223 DEF_VEC_P(constraint_t); 224 DEF_VEC_ALLOC_P(constraint_t,heap); 225 226 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \ 227 if (a) \ 228 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d) 229 230 static struct constraint_stats 231 { 232 unsigned int total_vars; 233 unsigned int nonpointer_vars; 234 unsigned int unified_vars_static; 235 unsigned int unified_vars_dynamic; 236 unsigned int iterations; 237 unsigned int num_edges; 238 unsigned int num_implicit_edges; 239 unsigned int points_to_sets_created; 240 } stats; 241 242 struct variable_info 243 { 244 /* ID of this variable */ 245 unsigned int id; 246 247 /* True if this is a variable created by the constraint analysis, such as 248 heap variables and constraints we had to break up. */ 249 unsigned int is_artificial_var : 1; 250 251 /* True if this is a special variable whose solution set should not be 252 changed. */ 253 unsigned int is_special_var : 1; 254 255 /* True for variables whose size is not known or variable. */ 256 unsigned int is_unknown_size_var : 1; 257 258 /* True for (sub-)fields that represent a whole variable. */ 259 unsigned int is_full_var : 1; 260 261 /* True if this is a heap variable. */ 262 unsigned int is_heap_var : 1; 263 264 /* True if this field may contain pointers. */ 265 unsigned int may_have_pointers : 1; 266 267 /* True if this field has only restrict qualified pointers. */ 268 unsigned int only_restrict_pointers : 1; 269 270 /* True if this represents a global variable. */ 271 unsigned int is_global_var : 1; 272 273 /* True if this represents a IPA function info. */ 274 unsigned int is_fn_info : 1; 275 276 /* A link to the variable for the next field in this structure. */ 277 struct variable_info *next; 278 279 /* Offset of this variable, in bits, from the base variable */ 280 unsigned HOST_WIDE_INT offset; 281 282 /* Size of the variable, in bits. */ 283 unsigned HOST_WIDE_INT size; 284 285 /* Full size of the base variable, in bits. */ 286 unsigned HOST_WIDE_INT fullsize; 287 288 /* Name of this variable */ 289 const char *name; 290 291 /* Tree that this variable is associated with. */ 292 tree decl; 293 294 /* Points-to set for this variable. */ 295 bitmap solution; 296 297 /* Old points-to set for this variable. */ 298 bitmap oldsolution; 299 }; 300 typedef struct variable_info *varinfo_t; 301 302 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT); 303 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t, 304 unsigned HOST_WIDE_INT); 305 static varinfo_t lookup_vi_for_tree (tree); 306 static inline bool type_can_have_subvars (const_tree); 307 308 /* Pool of variable info structures. */ 309 static alloc_pool variable_info_pool; 310 311 DEF_VEC_P(varinfo_t); 312 313 DEF_VEC_ALLOC_P(varinfo_t, heap); 314 315 /* Table of variable info structures for constraint variables. 316 Indexed directly by variable info id. */ 317 static VEC(varinfo_t,heap) *varmap; 318 319 /* Return the varmap element N */ 320 321 static inline varinfo_t 322 get_varinfo (unsigned int n) 323 { 324 return VEC_index (varinfo_t, varmap, n); 325 } 326 327 /* Static IDs for the special variables. */ 328 enum { nothing_id = 0, anything_id = 1, readonly_id = 2, 329 escaped_id = 3, nonlocal_id = 4, 330 storedanything_id = 5, integer_id = 6 }; 331 332 /* Return a new variable info structure consisting for a variable 333 named NAME, and using constraint graph node NODE. Append it 334 to the vector of variable info structures. */ 335 336 static varinfo_t 337 new_var_info (tree t, const char *name) 338 { 339 unsigned index = VEC_length (varinfo_t, varmap); 340 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool); 341 342 ret->id = index; 343 ret->name = name; 344 ret->decl = t; 345 /* Vars without decl are artificial and do not have sub-variables. */ 346 ret->is_artificial_var = (t == NULL_TREE); 347 ret->is_special_var = false; 348 ret->is_unknown_size_var = false; 349 ret->is_full_var = (t == NULL_TREE); 350 ret->is_heap_var = false; 351 ret->may_have_pointers = true; 352 ret->only_restrict_pointers = false; 353 ret->is_global_var = (t == NULL_TREE); 354 ret->is_fn_info = false; 355 if (t && DECL_P (t)) 356 ret->is_global_var = (is_global_var (t) 357 /* We have to treat even local register variables 358 as escape points. */ 359 || (TREE_CODE (t) == VAR_DECL 360 && DECL_HARD_REGISTER (t))); 361 ret->solution = BITMAP_ALLOC (&pta_obstack); 362 ret->oldsolution = NULL; 363 ret->next = NULL; 364 365 stats.total_vars++; 366 367 VEC_safe_push (varinfo_t, heap, varmap, ret); 368 369 return ret; 370 } 371 372 373 /* A map mapping call statements to per-stmt variables for uses 374 and clobbers specific to the call. */ 375 struct pointer_map_t *call_stmt_vars; 376 377 /* Lookup or create the variable for the call statement CALL. */ 378 379 static varinfo_t 380 get_call_vi (gimple call) 381 { 382 void **slot_p; 383 varinfo_t vi, vi2; 384 385 slot_p = pointer_map_insert (call_stmt_vars, call); 386 if (*slot_p) 387 return (varinfo_t) *slot_p; 388 389 vi = new_var_info (NULL_TREE, "CALLUSED"); 390 vi->offset = 0; 391 vi->size = 1; 392 vi->fullsize = 2; 393 vi->is_full_var = true; 394 395 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED"); 396 vi2->offset = 1; 397 vi2->size = 1; 398 vi2->fullsize = 2; 399 vi2->is_full_var = true; 400 401 *slot_p = (void *) vi; 402 return vi; 403 } 404 405 /* Lookup the variable for the call statement CALL representing 406 the uses. Returns NULL if there is nothing special about this call. */ 407 408 static varinfo_t 409 lookup_call_use_vi (gimple call) 410 { 411 void **slot_p; 412 413 slot_p = pointer_map_contains (call_stmt_vars, call); 414 if (slot_p) 415 return (varinfo_t) *slot_p; 416 417 return NULL; 418 } 419 420 /* Lookup the variable for the call statement CALL representing 421 the clobbers. Returns NULL if there is nothing special about this call. */ 422 423 static varinfo_t 424 lookup_call_clobber_vi (gimple call) 425 { 426 varinfo_t uses = lookup_call_use_vi (call); 427 if (!uses) 428 return NULL; 429 430 return uses->next; 431 } 432 433 /* Lookup or create the variable for the call statement CALL representing 434 the uses. */ 435 436 static varinfo_t 437 get_call_use_vi (gimple call) 438 { 439 return get_call_vi (call); 440 } 441 442 /* Lookup or create the variable for the call statement CALL representing 443 the clobbers. */ 444 445 static varinfo_t ATTRIBUTE_UNUSED 446 get_call_clobber_vi (gimple call) 447 { 448 return get_call_vi (call)->next; 449 } 450 451 452 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type; 453 454 /* An expression that appears in a constraint. */ 455 456 struct constraint_expr 457 { 458 /* Constraint type. */ 459 constraint_expr_type type; 460 461 /* Variable we are referring to in the constraint. */ 462 unsigned int var; 463 464 /* Offset, in bits, of this constraint from the beginning of 465 variables it ends up referring to. 466 467 IOW, in a deref constraint, we would deref, get the result set, 468 then add OFFSET to each member. */ 469 HOST_WIDE_INT offset; 470 }; 471 472 /* Use 0x8000... as special unknown offset. */ 473 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1)) 474 475 typedef struct constraint_expr ce_s; 476 DEF_VEC_O(ce_s); 477 DEF_VEC_ALLOC_O(ce_s, heap); 478 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool, bool); 479 static void get_constraint_for (tree, VEC(ce_s, heap) **); 480 static void get_constraint_for_rhs (tree, VEC(ce_s, heap) **); 481 static void do_deref (VEC (ce_s, heap) **); 482 483 /* Our set constraints are made up of two constraint expressions, one 484 LHS, and one RHS. 485 486 As described in the introduction, our set constraints each represent an 487 operation between set valued variables. 488 */ 489 struct constraint 490 { 491 struct constraint_expr lhs; 492 struct constraint_expr rhs; 493 }; 494 495 /* List of constraints that we use to build the constraint graph from. */ 496 497 static VEC(constraint_t,heap) *constraints; 498 static alloc_pool constraint_pool; 499 500 /* The constraint graph is represented as an array of bitmaps 501 containing successor nodes. */ 502 503 struct constraint_graph 504 { 505 /* Size of this graph, which may be different than the number of 506 nodes in the variable map. */ 507 unsigned int size; 508 509 /* Explicit successors of each node. */ 510 bitmap *succs; 511 512 /* Implicit predecessors of each node (Used for variable 513 substitution). */ 514 bitmap *implicit_preds; 515 516 /* Explicit predecessors of each node (Used for variable substitution). */ 517 bitmap *preds; 518 519 /* Indirect cycle representatives, or -1 if the node has no indirect 520 cycles. */ 521 int *indirect_cycles; 522 523 /* Representative node for a node. rep[a] == a unless the node has 524 been unified. */ 525 unsigned int *rep; 526 527 /* Equivalence class representative for a label. This is used for 528 variable substitution. */ 529 int *eq_rep; 530 531 /* Pointer equivalence label for a node. All nodes with the same 532 pointer equivalence label can be unified together at some point 533 (either during constraint optimization or after the constraint 534 graph is built). */ 535 unsigned int *pe; 536 537 /* Pointer equivalence representative for a label. This is used to 538 handle nodes that are pointer equivalent but not location 539 equivalent. We can unite these once the addressof constraints 540 are transformed into initial points-to sets. */ 541 int *pe_rep; 542 543 /* Pointer equivalence label for each node, used during variable 544 substitution. */ 545 unsigned int *pointer_label; 546 547 /* Location equivalence label for each node, used during location 548 equivalence finding. */ 549 unsigned int *loc_label; 550 551 /* Pointed-by set for each node, used during location equivalence 552 finding. This is pointed-by rather than pointed-to, because it 553 is constructed using the predecessor graph. */ 554 bitmap *pointed_by; 555 556 /* Points to sets for pointer equivalence. This is *not* the actual 557 points-to sets for nodes. */ 558 bitmap *points_to; 559 560 /* Bitmap of nodes where the bit is set if the node is a direct 561 node. Used for variable substitution. */ 562 sbitmap direct_nodes; 563 564 /* Bitmap of nodes where the bit is set if the node is address 565 taken. Used for variable substitution. */ 566 bitmap address_taken; 567 568 /* Vector of complex constraints for each graph node. Complex 569 constraints are those involving dereferences or offsets that are 570 not 0. */ 571 VEC(constraint_t,heap) **complex; 572 }; 573 574 static constraint_graph_t graph; 575 576 /* During variable substitution and the offline version of indirect 577 cycle finding, we create nodes to represent dereferences and 578 address taken constraints. These represent where these start and 579 end. */ 580 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap)) 581 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1)) 582 583 /* Return the representative node for NODE, if NODE has been unioned 584 with another NODE. 585 This function performs path compression along the way to finding 586 the representative. */ 587 588 static unsigned int 589 find (unsigned int node) 590 { 591 gcc_assert (node < graph->size); 592 if (graph->rep[node] != node) 593 return graph->rep[node] = find (graph->rep[node]); 594 return node; 595 } 596 597 /* Union the TO and FROM nodes to the TO nodes. 598 Note that at some point in the future, we may want to do 599 union-by-rank, in which case we are going to have to return the 600 node we unified to. */ 601 602 static bool 603 unite (unsigned int to, unsigned int from) 604 { 605 gcc_assert (to < graph->size && from < graph->size); 606 if (to != from && graph->rep[from] != to) 607 { 608 graph->rep[from] = to; 609 return true; 610 } 611 return false; 612 } 613 614 /* Create a new constraint consisting of LHS and RHS expressions. */ 615 616 static constraint_t 617 new_constraint (const struct constraint_expr lhs, 618 const struct constraint_expr rhs) 619 { 620 constraint_t ret = (constraint_t) pool_alloc (constraint_pool); 621 ret->lhs = lhs; 622 ret->rhs = rhs; 623 return ret; 624 } 625 626 /* Print out constraint C to FILE. */ 627 628 static void 629 dump_constraint (FILE *file, constraint_t c) 630 { 631 if (c->lhs.type == ADDRESSOF) 632 fprintf (file, "&"); 633 else if (c->lhs.type == DEREF) 634 fprintf (file, "*"); 635 fprintf (file, "%s", get_varinfo (c->lhs.var)->name); 636 if (c->lhs.offset == UNKNOWN_OFFSET) 637 fprintf (file, " + UNKNOWN"); 638 else if (c->lhs.offset != 0) 639 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset); 640 fprintf (file, " = "); 641 if (c->rhs.type == ADDRESSOF) 642 fprintf (file, "&"); 643 else if (c->rhs.type == DEREF) 644 fprintf (file, "*"); 645 fprintf (file, "%s", get_varinfo (c->rhs.var)->name); 646 if (c->rhs.offset == UNKNOWN_OFFSET) 647 fprintf (file, " + UNKNOWN"); 648 else if (c->rhs.offset != 0) 649 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset); 650 } 651 652 653 void debug_constraint (constraint_t); 654 void debug_constraints (void); 655 void debug_constraint_graph (void); 656 void debug_solution_for_var (unsigned int); 657 void debug_sa_points_to_info (void); 658 659 /* Print out constraint C to stderr. */ 660 661 DEBUG_FUNCTION void 662 debug_constraint (constraint_t c) 663 { 664 dump_constraint (stderr, c); 665 fprintf (stderr, "\n"); 666 } 667 668 /* Print out all constraints to FILE */ 669 670 static void 671 dump_constraints (FILE *file, int from) 672 { 673 int i; 674 constraint_t c; 675 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++) 676 if (c) 677 { 678 dump_constraint (file, c); 679 fprintf (file, "\n"); 680 } 681 } 682 683 /* Print out all constraints to stderr. */ 684 685 DEBUG_FUNCTION void 686 debug_constraints (void) 687 { 688 dump_constraints (stderr, 0); 689 } 690 691 /* Print the constraint graph in dot format. */ 692 693 static void 694 dump_constraint_graph (FILE *file) 695 { 696 unsigned int i; 697 698 /* Only print the graph if it has already been initialized: */ 699 if (!graph) 700 return; 701 702 /* Prints the header of the dot file: */ 703 fprintf (file, "strict digraph {\n"); 704 fprintf (file, " node [\n shape = box\n ]\n"); 705 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n"); 706 fprintf (file, "\n // List of nodes and complex constraints in " 707 "the constraint graph:\n"); 708 709 /* The next lines print the nodes in the graph together with the 710 complex constraints attached to them. */ 711 for (i = 0; i < graph->size; i++) 712 { 713 if (find (i) != i) 714 continue; 715 if (i < FIRST_REF_NODE) 716 fprintf (file, "\"%s\"", get_varinfo (i)->name); 717 else 718 fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name); 719 if (graph->complex[i]) 720 { 721 unsigned j; 722 constraint_t c; 723 fprintf (file, " [label=\"\\N\\n"); 724 for (j = 0; VEC_iterate (constraint_t, graph->complex[i], j, c); ++j) 725 { 726 dump_constraint (file, c); 727 fprintf (file, "\\l"); 728 } 729 fprintf (file, "\"]"); 730 } 731 fprintf (file, ";\n"); 732 } 733 734 /* Go over the edges. */ 735 fprintf (file, "\n // Edges in the constraint graph:\n"); 736 for (i = 0; i < graph->size; i++) 737 { 738 unsigned j; 739 bitmap_iterator bi; 740 if (find (i) != i) 741 continue; 742 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i], 0, j, bi) 743 { 744 unsigned to = find (j); 745 if (i == to) 746 continue; 747 if (i < FIRST_REF_NODE) 748 fprintf (file, "\"%s\"", get_varinfo (i)->name); 749 else 750 fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name); 751 fprintf (file, " -> "); 752 if (to < FIRST_REF_NODE) 753 fprintf (file, "\"%s\"", get_varinfo (to)->name); 754 else 755 fprintf (file, "\"*%s\"", get_varinfo (to - FIRST_REF_NODE)->name); 756 fprintf (file, ";\n"); 757 } 758 } 759 760 /* Prints the tail of the dot file. */ 761 fprintf (file, "}\n"); 762 } 763 764 /* Print out the constraint graph to stderr. */ 765 766 DEBUG_FUNCTION void 767 debug_constraint_graph (void) 768 { 769 dump_constraint_graph (stderr); 770 } 771 772 /* SOLVER FUNCTIONS 773 774 The solver is a simple worklist solver, that works on the following 775 algorithm: 776 777 sbitmap changed_nodes = all zeroes; 778 changed_count = 0; 779 For each node that is not already collapsed: 780 changed_count++; 781 set bit in changed nodes 782 783 while (changed_count > 0) 784 { 785 compute topological ordering for constraint graph 786 787 find and collapse cycles in the constraint graph (updating 788 changed if necessary) 789 790 for each node (n) in the graph in topological order: 791 changed_count--; 792 793 Process each complex constraint associated with the node, 794 updating changed if necessary. 795 796 For each outgoing edge from n, propagate the solution from n to 797 the destination of the edge, updating changed as necessary. 798 799 } */ 800 801 /* Return true if two constraint expressions A and B are equal. */ 802 803 static bool 804 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b) 805 { 806 return a.type == b.type && a.var == b.var && a.offset == b.offset; 807 } 808 809 /* Return true if constraint expression A is less than constraint expression 810 B. This is just arbitrary, but consistent, in order to give them an 811 ordering. */ 812 813 static bool 814 constraint_expr_less (struct constraint_expr a, struct constraint_expr b) 815 { 816 if (a.type == b.type) 817 { 818 if (a.var == b.var) 819 return a.offset < b.offset; 820 else 821 return a.var < b.var; 822 } 823 else 824 return a.type < b.type; 825 } 826 827 /* Return true if constraint A is less than constraint B. This is just 828 arbitrary, but consistent, in order to give them an ordering. */ 829 830 static bool 831 constraint_less (const constraint_t a, const constraint_t b) 832 { 833 if (constraint_expr_less (a->lhs, b->lhs)) 834 return true; 835 else if (constraint_expr_less (b->lhs, a->lhs)) 836 return false; 837 else 838 return constraint_expr_less (a->rhs, b->rhs); 839 } 840 841 /* Return true if two constraints A and B are equal. */ 842 843 static bool 844 constraint_equal (struct constraint a, struct constraint b) 845 { 846 return constraint_expr_equal (a.lhs, b.lhs) 847 && constraint_expr_equal (a.rhs, b.rhs); 848 } 849 850 851 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */ 852 853 static constraint_t 854 constraint_vec_find (VEC(constraint_t,heap) *vec, 855 struct constraint lookfor) 856 { 857 unsigned int place; 858 constraint_t found; 859 860 if (vec == NULL) 861 return NULL; 862 863 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less); 864 if (place >= VEC_length (constraint_t, vec)) 865 return NULL; 866 found = VEC_index (constraint_t, vec, place); 867 if (!constraint_equal (*found, lookfor)) 868 return NULL; 869 return found; 870 } 871 872 /* Union two constraint vectors, TO and FROM. Put the result in TO. */ 873 874 static void 875 constraint_set_union (VEC(constraint_t,heap) **to, 876 VEC(constraint_t,heap) **from) 877 { 878 int i; 879 constraint_t c; 880 881 FOR_EACH_VEC_ELT (constraint_t, *from, i, c) 882 { 883 if (constraint_vec_find (*to, *c) == NULL) 884 { 885 unsigned int place = VEC_lower_bound (constraint_t, *to, c, 886 constraint_less); 887 VEC_safe_insert (constraint_t, heap, *to, place, c); 888 } 889 } 890 } 891 892 /* Expands the solution in SET to all sub-fields of variables included. 893 Union the expanded result into RESULT. */ 894 895 static void 896 solution_set_expand (bitmap result, bitmap set) 897 { 898 bitmap_iterator bi; 899 bitmap vars = NULL; 900 unsigned j; 901 902 /* In a first pass record all variables we need to add all 903 sub-fields off. This avoids quadratic behavior. */ 904 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi) 905 { 906 varinfo_t v = get_varinfo (j); 907 if (v->is_artificial_var 908 || v->is_full_var) 909 continue; 910 v = lookup_vi_for_tree (v->decl); 911 if (vars == NULL) 912 vars = BITMAP_ALLOC (NULL); 913 bitmap_set_bit (vars, v->id); 914 } 915 916 /* In the second pass now do the addition to the solution and 917 to speed up solving add it to the delta as well. */ 918 if (vars != NULL) 919 { 920 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi) 921 { 922 varinfo_t v = get_varinfo (j); 923 for (; v != NULL; v = v->next) 924 bitmap_set_bit (result, v->id); 925 } 926 BITMAP_FREE (vars); 927 } 928 } 929 930 /* Take a solution set SET, add OFFSET to each member of the set, and 931 overwrite SET with the result when done. */ 932 933 static void 934 solution_set_add (bitmap set, HOST_WIDE_INT offset) 935 { 936 bitmap result = BITMAP_ALLOC (&iteration_obstack); 937 unsigned int i; 938 bitmap_iterator bi; 939 940 /* If the offset is unknown we have to expand the solution to 941 all subfields. */ 942 if (offset == UNKNOWN_OFFSET) 943 { 944 solution_set_expand (set, set); 945 return; 946 } 947 948 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) 949 { 950 varinfo_t vi = get_varinfo (i); 951 952 /* If this is a variable with just one field just set its bit 953 in the result. */ 954 if (vi->is_artificial_var 955 || vi->is_unknown_size_var 956 || vi->is_full_var) 957 bitmap_set_bit (result, i); 958 else 959 { 960 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset; 961 962 /* If the offset makes the pointer point to before the 963 variable use offset zero for the field lookup. */ 964 if (offset < 0 965 && fieldoffset > vi->offset) 966 fieldoffset = 0; 967 968 if (offset != 0) 969 vi = first_or_preceding_vi_for_offset (vi, fieldoffset); 970 971 bitmap_set_bit (result, vi->id); 972 /* If the result is not exactly at fieldoffset include the next 973 field as well. See get_constraint_for_ptr_offset for more 974 rationale. */ 975 if (vi->offset != fieldoffset 976 && vi->next != NULL) 977 bitmap_set_bit (result, vi->next->id); 978 } 979 } 980 981 bitmap_copy (set, result); 982 BITMAP_FREE (result); 983 } 984 985 /* Union solution sets TO and FROM, and add INC to each member of FROM in the 986 process. */ 987 988 static bool 989 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc) 990 { 991 if (inc == 0) 992 return bitmap_ior_into (to, from); 993 else 994 { 995 bitmap tmp; 996 bool res; 997 998 tmp = BITMAP_ALLOC (&iteration_obstack); 999 bitmap_copy (tmp, from); 1000 solution_set_add (tmp, inc); 1001 res = bitmap_ior_into (to, tmp); 1002 BITMAP_FREE (tmp); 1003 return res; 1004 } 1005 } 1006 1007 /* Insert constraint C into the list of complex constraints for graph 1008 node VAR. */ 1009 1010 static void 1011 insert_into_complex (constraint_graph_t graph, 1012 unsigned int var, constraint_t c) 1013 { 1014 VEC (constraint_t, heap) *complex = graph->complex[var]; 1015 unsigned int place = VEC_lower_bound (constraint_t, complex, c, 1016 constraint_less); 1017 1018 /* Only insert constraints that do not already exist. */ 1019 if (place >= VEC_length (constraint_t, complex) 1020 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place))) 1021 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c); 1022 } 1023 1024 1025 /* Condense two variable nodes into a single variable node, by moving 1026 all associated info from SRC to TO. */ 1027 1028 static void 1029 merge_node_constraints (constraint_graph_t graph, unsigned int to, 1030 unsigned int from) 1031 { 1032 unsigned int i; 1033 constraint_t c; 1034 1035 gcc_assert (find (from) == to); 1036 1037 /* Move all complex constraints from src node into to node */ 1038 FOR_EACH_VEC_ELT (constraint_t, graph->complex[from], i, c) 1039 { 1040 /* In complex constraints for node src, we may have either 1041 a = *src, and *src = a, or an offseted constraint which are 1042 always added to the rhs node's constraints. */ 1043 1044 if (c->rhs.type == DEREF) 1045 c->rhs.var = to; 1046 else if (c->lhs.type == DEREF) 1047 c->lhs.var = to; 1048 else 1049 c->rhs.var = to; 1050 } 1051 constraint_set_union (&graph->complex[to], &graph->complex[from]); 1052 VEC_free (constraint_t, heap, graph->complex[from]); 1053 graph->complex[from] = NULL; 1054 } 1055 1056 1057 /* Remove edges involving NODE from GRAPH. */ 1058 1059 static void 1060 clear_edges_for_node (constraint_graph_t graph, unsigned int node) 1061 { 1062 if (graph->succs[node]) 1063 BITMAP_FREE (graph->succs[node]); 1064 } 1065 1066 /* Merge GRAPH nodes FROM and TO into node TO. */ 1067 1068 static void 1069 merge_graph_nodes (constraint_graph_t graph, unsigned int to, 1070 unsigned int from) 1071 { 1072 if (graph->indirect_cycles[from] != -1) 1073 { 1074 /* If we have indirect cycles with the from node, and we have 1075 none on the to node, the to node has indirect cycles from the 1076 from node now that they are unified. 1077 If indirect cycles exist on both, unify the nodes that they 1078 are in a cycle with, since we know they are in a cycle with 1079 each other. */ 1080 if (graph->indirect_cycles[to] == -1) 1081 graph->indirect_cycles[to] = graph->indirect_cycles[from]; 1082 } 1083 1084 /* Merge all the successor edges. */ 1085 if (graph->succs[from]) 1086 { 1087 if (!graph->succs[to]) 1088 graph->succs[to] = BITMAP_ALLOC (&pta_obstack); 1089 bitmap_ior_into (graph->succs[to], 1090 graph->succs[from]); 1091 } 1092 1093 clear_edges_for_node (graph, from); 1094 } 1095 1096 1097 /* Add an indirect graph edge to GRAPH, going from TO to FROM if 1098 it doesn't exist in the graph already. */ 1099 1100 static void 1101 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to, 1102 unsigned int from) 1103 { 1104 if (to == from) 1105 return; 1106 1107 if (!graph->implicit_preds[to]) 1108 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack); 1109 1110 if (bitmap_set_bit (graph->implicit_preds[to], from)) 1111 stats.num_implicit_edges++; 1112 } 1113 1114 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if 1115 it doesn't exist in the graph already. 1116 Return false if the edge already existed, true otherwise. */ 1117 1118 static void 1119 add_pred_graph_edge (constraint_graph_t graph, unsigned int to, 1120 unsigned int from) 1121 { 1122 if (!graph->preds[to]) 1123 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack); 1124 bitmap_set_bit (graph->preds[to], from); 1125 } 1126 1127 /* Add a graph edge to GRAPH, going from FROM to TO if 1128 it doesn't exist in the graph already. 1129 Return false if the edge already existed, true otherwise. */ 1130 1131 static bool 1132 add_graph_edge (constraint_graph_t graph, unsigned int to, 1133 unsigned int from) 1134 { 1135 if (to == from) 1136 { 1137 return false; 1138 } 1139 else 1140 { 1141 bool r = false; 1142 1143 if (!graph->succs[from]) 1144 graph->succs[from] = BITMAP_ALLOC (&pta_obstack); 1145 if (bitmap_set_bit (graph->succs[from], to)) 1146 { 1147 r = true; 1148 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE) 1149 stats.num_edges++; 1150 } 1151 return r; 1152 } 1153 } 1154 1155 1156 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */ 1157 1158 static bool 1159 valid_graph_edge (constraint_graph_t graph, unsigned int src, 1160 unsigned int dest) 1161 { 1162 return (graph->succs[dest] 1163 && bitmap_bit_p (graph->succs[dest], src)); 1164 } 1165 1166 /* Initialize the constraint graph structure to contain SIZE nodes. */ 1167 1168 static void 1169 init_graph (unsigned int size) 1170 { 1171 unsigned int j; 1172 1173 graph = XCNEW (struct constraint_graph); 1174 graph->size = size; 1175 graph->succs = XCNEWVEC (bitmap, graph->size); 1176 graph->indirect_cycles = XNEWVEC (int, graph->size); 1177 graph->rep = XNEWVEC (unsigned int, graph->size); 1178 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size); 1179 graph->pe = XCNEWVEC (unsigned int, graph->size); 1180 graph->pe_rep = XNEWVEC (int, graph->size); 1181 1182 for (j = 0; j < graph->size; j++) 1183 { 1184 graph->rep[j] = j; 1185 graph->pe_rep[j] = -1; 1186 graph->indirect_cycles[j] = -1; 1187 } 1188 } 1189 1190 /* Build the constraint graph, adding only predecessor edges right now. */ 1191 1192 static void 1193 build_pred_graph (void) 1194 { 1195 int i; 1196 constraint_t c; 1197 unsigned int j; 1198 1199 graph->implicit_preds = XCNEWVEC (bitmap, graph->size); 1200 graph->preds = XCNEWVEC (bitmap, graph->size); 1201 graph->pointer_label = XCNEWVEC (unsigned int, graph->size); 1202 graph->loc_label = XCNEWVEC (unsigned int, graph->size); 1203 graph->pointed_by = XCNEWVEC (bitmap, graph->size); 1204 graph->points_to = XCNEWVEC (bitmap, graph->size); 1205 graph->eq_rep = XNEWVEC (int, graph->size); 1206 graph->direct_nodes = sbitmap_alloc (graph->size); 1207 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack); 1208 sbitmap_zero (graph->direct_nodes); 1209 1210 for (j = 0; j < FIRST_REF_NODE; j++) 1211 { 1212 if (!get_varinfo (j)->is_special_var) 1213 SET_BIT (graph->direct_nodes, j); 1214 } 1215 1216 for (j = 0; j < graph->size; j++) 1217 graph->eq_rep[j] = -1; 1218 1219 for (j = 0; j < VEC_length (varinfo_t, varmap); j++) 1220 graph->indirect_cycles[j] = -1; 1221 1222 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c) 1223 { 1224 struct constraint_expr lhs = c->lhs; 1225 struct constraint_expr rhs = c->rhs; 1226 unsigned int lhsvar = lhs.var; 1227 unsigned int rhsvar = rhs.var; 1228 1229 if (lhs.type == DEREF) 1230 { 1231 /* *x = y. */ 1232 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR) 1233 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar); 1234 } 1235 else if (rhs.type == DEREF) 1236 { 1237 /* x = *y */ 1238 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR) 1239 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar); 1240 else 1241 RESET_BIT (graph->direct_nodes, lhsvar); 1242 } 1243 else if (rhs.type == ADDRESSOF) 1244 { 1245 varinfo_t v; 1246 1247 /* x = &y */ 1248 if (graph->points_to[lhsvar] == NULL) 1249 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack); 1250 bitmap_set_bit (graph->points_to[lhsvar], rhsvar); 1251 1252 if (graph->pointed_by[rhsvar] == NULL) 1253 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack); 1254 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar); 1255 1256 /* Implicitly, *x = y */ 1257 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar); 1258 1259 /* All related variables are no longer direct nodes. */ 1260 RESET_BIT (graph->direct_nodes, rhsvar); 1261 v = get_varinfo (rhsvar); 1262 if (!v->is_full_var) 1263 { 1264 v = lookup_vi_for_tree (v->decl); 1265 do 1266 { 1267 RESET_BIT (graph->direct_nodes, v->id); 1268 v = v->next; 1269 } 1270 while (v != NULL); 1271 } 1272 bitmap_set_bit (graph->address_taken, rhsvar); 1273 } 1274 else if (lhsvar > anything_id 1275 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0) 1276 { 1277 /* x = y */ 1278 add_pred_graph_edge (graph, lhsvar, rhsvar); 1279 /* Implicitly, *x = *y */ 1280 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, 1281 FIRST_REF_NODE + rhsvar); 1282 } 1283 else if (lhs.offset != 0 || rhs.offset != 0) 1284 { 1285 if (rhs.offset != 0) 1286 RESET_BIT (graph->direct_nodes, lhs.var); 1287 else if (lhs.offset != 0) 1288 RESET_BIT (graph->direct_nodes, rhs.var); 1289 } 1290 } 1291 } 1292 1293 /* Build the constraint graph, adding successor edges. */ 1294 1295 static void 1296 build_succ_graph (void) 1297 { 1298 unsigned i, t; 1299 constraint_t c; 1300 1301 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c) 1302 { 1303 struct constraint_expr lhs; 1304 struct constraint_expr rhs; 1305 unsigned int lhsvar; 1306 unsigned int rhsvar; 1307 1308 if (!c) 1309 continue; 1310 1311 lhs = c->lhs; 1312 rhs = c->rhs; 1313 lhsvar = find (lhs.var); 1314 rhsvar = find (rhs.var); 1315 1316 if (lhs.type == DEREF) 1317 { 1318 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR) 1319 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar); 1320 } 1321 else if (rhs.type == DEREF) 1322 { 1323 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR) 1324 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar); 1325 } 1326 else if (rhs.type == ADDRESSOF) 1327 { 1328 /* x = &y */ 1329 gcc_assert (find (rhs.var) == rhs.var); 1330 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar); 1331 } 1332 else if (lhsvar > anything_id 1333 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0) 1334 { 1335 add_graph_edge (graph, lhsvar, rhsvar); 1336 } 1337 } 1338 1339 /* Add edges from STOREDANYTHING to all non-direct nodes that can 1340 receive pointers. */ 1341 t = find (storedanything_id); 1342 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i) 1343 { 1344 if (!TEST_BIT (graph->direct_nodes, i) 1345 && get_varinfo (i)->may_have_pointers) 1346 add_graph_edge (graph, find (i), t); 1347 } 1348 1349 /* Everything stored to ANYTHING also potentially escapes. */ 1350 add_graph_edge (graph, find (escaped_id), t); 1351 } 1352 1353 1354 /* Changed variables on the last iteration. */ 1355 static bitmap changed; 1356 1357 /* Strongly Connected Component visitation info. */ 1358 1359 struct scc_info 1360 { 1361 sbitmap visited; 1362 sbitmap deleted; 1363 unsigned int *dfs; 1364 unsigned int *node_mapping; 1365 int current_index; 1366 VEC(unsigned,heap) *scc_stack; 1367 }; 1368 1369 1370 /* Recursive routine to find strongly connected components in GRAPH. 1371 SI is the SCC info to store the information in, and N is the id of current 1372 graph node we are processing. 1373 1374 This is Tarjan's strongly connected component finding algorithm, as 1375 modified by Nuutila to keep only non-root nodes on the stack. 1376 The algorithm can be found in "On finding the strongly connected 1377 connected components in a directed graph" by Esko Nuutila and Eljas 1378 Soisalon-Soininen, in Information Processing Letters volume 49, 1379 number 1, pages 9-14. */ 1380 1381 static void 1382 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n) 1383 { 1384 unsigned int i; 1385 bitmap_iterator bi; 1386 unsigned int my_dfs; 1387 1388 SET_BIT (si->visited, n); 1389 si->dfs[n] = si->current_index ++; 1390 my_dfs = si->dfs[n]; 1391 1392 /* Visit all the successors. */ 1393 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi) 1394 { 1395 unsigned int w; 1396 1397 if (i > LAST_REF_NODE) 1398 break; 1399 1400 w = find (i); 1401 if (TEST_BIT (si->deleted, w)) 1402 continue; 1403 1404 if (!TEST_BIT (si->visited, w)) 1405 scc_visit (graph, si, w); 1406 { 1407 unsigned int t = find (w); 1408 unsigned int nnode = find (n); 1409 gcc_assert (nnode == n); 1410 1411 if (si->dfs[t] < si->dfs[nnode]) 1412 si->dfs[n] = si->dfs[t]; 1413 } 1414 } 1415 1416 /* See if any components have been identified. */ 1417 if (si->dfs[n] == my_dfs) 1418 { 1419 if (VEC_length (unsigned, si->scc_stack) > 0 1420 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs) 1421 { 1422 bitmap scc = BITMAP_ALLOC (NULL); 1423 unsigned int lowest_node; 1424 bitmap_iterator bi; 1425 1426 bitmap_set_bit (scc, n); 1427 1428 while (VEC_length (unsigned, si->scc_stack) != 0 1429 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs) 1430 { 1431 unsigned int w = VEC_pop (unsigned, si->scc_stack); 1432 1433 bitmap_set_bit (scc, w); 1434 } 1435 1436 lowest_node = bitmap_first_set_bit (scc); 1437 gcc_assert (lowest_node < FIRST_REF_NODE); 1438 1439 /* Collapse the SCC nodes into a single node, and mark the 1440 indirect cycles. */ 1441 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi) 1442 { 1443 if (i < FIRST_REF_NODE) 1444 { 1445 if (unite (lowest_node, i)) 1446 unify_nodes (graph, lowest_node, i, false); 1447 } 1448 else 1449 { 1450 unite (lowest_node, i); 1451 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node; 1452 } 1453 } 1454 } 1455 SET_BIT (si->deleted, n); 1456 } 1457 else 1458 VEC_safe_push (unsigned, heap, si->scc_stack, n); 1459 } 1460 1461 /* Unify node FROM into node TO, updating the changed count if 1462 necessary when UPDATE_CHANGED is true. */ 1463 1464 static void 1465 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from, 1466 bool update_changed) 1467 { 1468 1469 gcc_assert (to != from && find (to) == to); 1470 if (dump_file && (dump_flags & TDF_DETAILS)) 1471 fprintf (dump_file, "Unifying %s to %s\n", 1472 get_varinfo (from)->name, 1473 get_varinfo (to)->name); 1474 1475 if (update_changed) 1476 stats.unified_vars_dynamic++; 1477 else 1478 stats.unified_vars_static++; 1479 1480 merge_graph_nodes (graph, to, from); 1481 merge_node_constraints (graph, to, from); 1482 1483 /* Mark TO as changed if FROM was changed. If TO was already marked 1484 as changed, decrease the changed count. */ 1485 1486 if (update_changed 1487 && bitmap_bit_p (changed, from)) 1488 { 1489 bitmap_clear_bit (changed, from); 1490 bitmap_set_bit (changed, to); 1491 } 1492 if (get_varinfo (from)->solution) 1493 { 1494 /* If the solution changes because of the merging, we need to mark 1495 the variable as changed. */ 1496 if (bitmap_ior_into (get_varinfo (to)->solution, 1497 get_varinfo (from)->solution)) 1498 { 1499 if (update_changed) 1500 bitmap_set_bit (changed, to); 1501 } 1502 1503 BITMAP_FREE (get_varinfo (from)->solution); 1504 if (get_varinfo (from)->oldsolution) 1505 BITMAP_FREE (get_varinfo (from)->oldsolution); 1506 1507 if (stats.iterations > 0 1508 && get_varinfo (to)->oldsolution) 1509 BITMAP_FREE (get_varinfo (to)->oldsolution); 1510 } 1511 if (valid_graph_edge (graph, to, to)) 1512 { 1513 if (graph->succs[to]) 1514 bitmap_clear_bit (graph->succs[to], to); 1515 } 1516 } 1517 1518 /* Information needed to compute the topological ordering of a graph. */ 1519 1520 struct topo_info 1521 { 1522 /* sbitmap of visited nodes. */ 1523 sbitmap visited; 1524 /* Array that stores the topological order of the graph, *in 1525 reverse*. */ 1526 VEC(unsigned,heap) *topo_order; 1527 }; 1528 1529 1530 /* Initialize and return a topological info structure. */ 1531 1532 static struct topo_info * 1533 init_topo_info (void) 1534 { 1535 size_t size = graph->size; 1536 struct topo_info *ti = XNEW (struct topo_info); 1537 ti->visited = sbitmap_alloc (size); 1538 sbitmap_zero (ti->visited); 1539 ti->topo_order = VEC_alloc (unsigned, heap, 1); 1540 return ti; 1541 } 1542 1543 1544 /* Free the topological sort info pointed to by TI. */ 1545 1546 static void 1547 free_topo_info (struct topo_info *ti) 1548 { 1549 sbitmap_free (ti->visited); 1550 VEC_free (unsigned, heap, ti->topo_order); 1551 free (ti); 1552 } 1553 1554 /* Visit the graph in topological order, and store the order in the 1555 topo_info structure. */ 1556 1557 static void 1558 topo_visit (constraint_graph_t graph, struct topo_info *ti, 1559 unsigned int n) 1560 { 1561 bitmap_iterator bi; 1562 unsigned int j; 1563 1564 SET_BIT (ti->visited, n); 1565 1566 if (graph->succs[n]) 1567 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi) 1568 { 1569 if (!TEST_BIT (ti->visited, j)) 1570 topo_visit (graph, ti, j); 1571 } 1572 1573 VEC_safe_push (unsigned, heap, ti->topo_order, n); 1574 } 1575 1576 /* Process a constraint C that represents x = *(y + off), using DELTA as the 1577 starting solution for y. */ 1578 1579 static void 1580 do_sd_constraint (constraint_graph_t graph, constraint_t c, 1581 bitmap delta) 1582 { 1583 unsigned int lhs = c->lhs.var; 1584 bool flag = false; 1585 bitmap sol = get_varinfo (lhs)->solution; 1586 unsigned int j; 1587 bitmap_iterator bi; 1588 HOST_WIDE_INT roffset = c->rhs.offset; 1589 1590 /* Our IL does not allow this. */ 1591 gcc_assert (c->lhs.offset == 0); 1592 1593 /* If the solution of Y contains anything it is good enough to transfer 1594 this to the LHS. */ 1595 if (bitmap_bit_p (delta, anything_id)) 1596 { 1597 flag |= bitmap_set_bit (sol, anything_id); 1598 goto done; 1599 } 1600 1601 /* If we do not know at with offset the rhs is dereferenced compute 1602 the reachability set of DELTA, conservatively assuming it is 1603 dereferenced at all valid offsets. */ 1604 if (roffset == UNKNOWN_OFFSET) 1605 { 1606 solution_set_expand (delta, delta); 1607 /* No further offset processing is necessary. */ 1608 roffset = 0; 1609 } 1610 1611 /* For each variable j in delta (Sol(y)), add 1612 an edge in the graph from j to x, and union Sol(j) into Sol(x). */ 1613 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi) 1614 { 1615 varinfo_t v = get_varinfo (j); 1616 HOST_WIDE_INT fieldoffset = v->offset + roffset; 1617 unsigned int t; 1618 1619 if (v->is_full_var) 1620 fieldoffset = v->offset; 1621 else if (roffset != 0) 1622 v = first_vi_for_offset (v, fieldoffset); 1623 /* If the access is outside of the variable we can ignore it. */ 1624 if (!v) 1625 continue; 1626 1627 do 1628 { 1629 t = find (v->id); 1630 1631 /* Adding edges from the special vars is pointless. 1632 They don't have sets that can change. */ 1633 if (get_varinfo (t)->is_special_var) 1634 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution); 1635 /* Merging the solution from ESCAPED needlessly increases 1636 the set. Use ESCAPED as representative instead. */ 1637 else if (v->id == escaped_id) 1638 flag |= bitmap_set_bit (sol, escaped_id); 1639 else if (v->may_have_pointers 1640 && add_graph_edge (graph, lhs, t)) 1641 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution); 1642 1643 /* If the variable is not exactly at the requested offset 1644 we have to include the next one. */ 1645 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset 1646 || v->next == NULL) 1647 break; 1648 1649 v = v->next; 1650 fieldoffset = v->offset; 1651 } 1652 while (1); 1653 } 1654 1655 done: 1656 /* If the LHS solution changed, mark the var as changed. */ 1657 if (flag) 1658 { 1659 get_varinfo (lhs)->solution = sol; 1660 bitmap_set_bit (changed, lhs); 1661 } 1662 } 1663 1664 /* Process a constraint C that represents *(x + off) = y using DELTA 1665 as the starting solution for x. */ 1666 1667 static void 1668 do_ds_constraint (constraint_t c, bitmap delta) 1669 { 1670 unsigned int rhs = c->rhs.var; 1671 bitmap sol = get_varinfo (rhs)->solution; 1672 unsigned int j; 1673 bitmap_iterator bi; 1674 HOST_WIDE_INT loff = c->lhs.offset; 1675 bool escaped_p = false; 1676 1677 /* Our IL does not allow this. */ 1678 gcc_assert (c->rhs.offset == 0); 1679 1680 /* If the solution of y contains ANYTHING simply use the ANYTHING 1681 solution. This avoids needlessly increasing the points-to sets. */ 1682 if (bitmap_bit_p (sol, anything_id)) 1683 sol = get_varinfo (find (anything_id))->solution; 1684 1685 /* If the solution for x contains ANYTHING we have to merge the 1686 solution of y into all pointer variables which we do via 1687 STOREDANYTHING. */ 1688 if (bitmap_bit_p (delta, anything_id)) 1689 { 1690 unsigned t = find (storedanything_id); 1691 if (add_graph_edge (graph, t, rhs)) 1692 { 1693 if (bitmap_ior_into (get_varinfo (t)->solution, sol)) 1694 bitmap_set_bit (changed, t); 1695 } 1696 return; 1697 } 1698 1699 /* If we do not know at with offset the rhs is dereferenced compute 1700 the reachability set of DELTA, conservatively assuming it is 1701 dereferenced at all valid offsets. */ 1702 if (loff == UNKNOWN_OFFSET) 1703 { 1704 solution_set_expand (delta, delta); 1705 loff = 0; 1706 } 1707 1708 /* For each member j of delta (Sol(x)), add an edge from y to j and 1709 union Sol(y) into Sol(j) */ 1710 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi) 1711 { 1712 varinfo_t v = get_varinfo (j); 1713 unsigned int t; 1714 HOST_WIDE_INT fieldoffset = v->offset + loff; 1715 1716 if (v->is_full_var) 1717 fieldoffset = v->offset; 1718 else if (loff != 0) 1719 v = first_vi_for_offset (v, fieldoffset); 1720 /* If the access is outside of the variable we can ignore it. */ 1721 if (!v) 1722 continue; 1723 1724 do 1725 { 1726 if (v->may_have_pointers) 1727 { 1728 /* If v is a global variable then this is an escape point. */ 1729 if (v->is_global_var 1730 && !escaped_p) 1731 { 1732 t = find (escaped_id); 1733 if (add_graph_edge (graph, t, rhs) 1734 && bitmap_ior_into (get_varinfo (t)->solution, sol)) 1735 bitmap_set_bit (changed, t); 1736 /* Enough to let rhs escape once. */ 1737 escaped_p = true; 1738 } 1739 1740 if (v->is_special_var) 1741 break; 1742 1743 t = find (v->id); 1744 if (add_graph_edge (graph, t, rhs) 1745 && bitmap_ior_into (get_varinfo (t)->solution, sol)) 1746 bitmap_set_bit (changed, t); 1747 } 1748 1749 /* If the variable is not exactly at the requested offset 1750 we have to include the next one. */ 1751 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset 1752 || v->next == NULL) 1753 break; 1754 1755 v = v->next; 1756 fieldoffset = v->offset; 1757 } 1758 while (1); 1759 } 1760 } 1761 1762 /* Handle a non-simple (simple meaning requires no iteration), 1763 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */ 1764 1765 static void 1766 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta) 1767 { 1768 if (c->lhs.type == DEREF) 1769 { 1770 if (c->rhs.type == ADDRESSOF) 1771 { 1772 gcc_unreachable(); 1773 } 1774 else 1775 { 1776 /* *x = y */ 1777 do_ds_constraint (c, delta); 1778 } 1779 } 1780 else if (c->rhs.type == DEREF) 1781 { 1782 /* x = *y */ 1783 if (!(get_varinfo (c->lhs.var)->is_special_var)) 1784 do_sd_constraint (graph, c, delta); 1785 } 1786 else 1787 { 1788 bitmap tmp; 1789 bitmap solution; 1790 bool flag = false; 1791 1792 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR); 1793 solution = get_varinfo (c->rhs.var)->solution; 1794 tmp = get_varinfo (c->lhs.var)->solution; 1795 1796 flag = set_union_with_increment (tmp, solution, c->rhs.offset); 1797 1798 if (flag) 1799 { 1800 get_varinfo (c->lhs.var)->solution = tmp; 1801 bitmap_set_bit (changed, c->lhs.var); 1802 } 1803 } 1804 } 1805 1806 /* Initialize and return a new SCC info structure. */ 1807 1808 static struct scc_info * 1809 init_scc_info (size_t size) 1810 { 1811 struct scc_info *si = XNEW (struct scc_info); 1812 size_t i; 1813 1814 si->current_index = 0; 1815 si->visited = sbitmap_alloc (size); 1816 sbitmap_zero (si->visited); 1817 si->deleted = sbitmap_alloc (size); 1818 sbitmap_zero (si->deleted); 1819 si->node_mapping = XNEWVEC (unsigned int, size); 1820 si->dfs = XCNEWVEC (unsigned int, size); 1821 1822 for (i = 0; i < size; i++) 1823 si->node_mapping[i] = i; 1824 1825 si->scc_stack = VEC_alloc (unsigned, heap, 1); 1826 return si; 1827 } 1828 1829 /* Free an SCC info structure pointed to by SI */ 1830 1831 static void 1832 free_scc_info (struct scc_info *si) 1833 { 1834 sbitmap_free (si->visited); 1835 sbitmap_free (si->deleted); 1836 free (si->node_mapping); 1837 free (si->dfs); 1838 VEC_free (unsigned, heap, si->scc_stack); 1839 free (si); 1840 } 1841 1842 1843 /* Find indirect cycles in GRAPH that occur, using strongly connected 1844 components, and note them in the indirect cycles map. 1845 1846 This technique comes from Ben Hardekopf and Calvin Lin, 1847 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of 1848 Lines of Code", submitted to PLDI 2007. */ 1849 1850 static void 1851 find_indirect_cycles (constraint_graph_t graph) 1852 { 1853 unsigned int i; 1854 unsigned int size = graph->size; 1855 struct scc_info *si = init_scc_info (size); 1856 1857 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ ) 1858 if (!TEST_BIT (si->visited, i) && find (i) == i) 1859 scc_visit (graph, si, i); 1860 1861 free_scc_info (si); 1862 } 1863 1864 /* Compute a topological ordering for GRAPH, and store the result in the 1865 topo_info structure TI. */ 1866 1867 static void 1868 compute_topo_order (constraint_graph_t graph, 1869 struct topo_info *ti) 1870 { 1871 unsigned int i; 1872 unsigned int size = graph->size; 1873 1874 for (i = 0; i != size; ++i) 1875 if (!TEST_BIT (ti->visited, i) && find (i) == i) 1876 topo_visit (graph, ti, i); 1877 } 1878 1879 /* Structure used to for hash value numbering of pointer equivalence 1880 classes. */ 1881 1882 typedef struct equiv_class_label 1883 { 1884 hashval_t hashcode; 1885 unsigned int equivalence_class; 1886 bitmap labels; 1887 } *equiv_class_label_t; 1888 typedef const struct equiv_class_label *const_equiv_class_label_t; 1889 1890 /* A hashtable for mapping a bitmap of labels->pointer equivalence 1891 classes. */ 1892 static htab_t pointer_equiv_class_table; 1893 1894 /* A hashtable for mapping a bitmap of labels->location equivalence 1895 classes. */ 1896 static htab_t location_equiv_class_table; 1897 1898 /* Hash function for a equiv_class_label_t */ 1899 1900 static hashval_t 1901 equiv_class_label_hash (const void *p) 1902 { 1903 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p; 1904 return ecl->hashcode; 1905 } 1906 1907 /* Equality function for two equiv_class_label_t's. */ 1908 1909 static int 1910 equiv_class_label_eq (const void *p1, const void *p2) 1911 { 1912 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1; 1913 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2; 1914 return (eql1->hashcode == eql2->hashcode 1915 && bitmap_equal_p (eql1->labels, eql2->labels)); 1916 } 1917 1918 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it 1919 contains. Sets *REF_LABELS to the bitmap LABELS is equivalent to. */ 1920 1921 static unsigned int 1922 equiv_class_lookup (htab_t table, bitmap labels, bitmap *ref_labels) 1923 { 1924 void **slot; 1925 struct equiv_class_label ecl; 1926 1927 ecl.labels = labels; 1928 ecl.hashcode = bitmap_hash (labels); 1929 1930 slot = htab_find_slot_with_hash (table, &ecl, 1931 ecl.hashcode, NO_INSERT); 1932 if (!slot) 1933 { 1934 if (ref_labels) 1935 *ref_labels = NULL; 1936 return 0; 1937 } 1938 else 1939 { 1940 equiv_class_label_t ec = (equiv_class_label_t) *slot; 1941 if (ref_labels) 1942 *ref_labels = ec->labels; 1943 return ec->equivalence_class; 1944 } 1945 } 1946 1947 1948 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS 1949 to TABLE. */ 1950 1951 static void 1952 equiv_class_add (htab_t table, unsigned int equivalence_class, 1953 bitmap labels) 1954 { 1955 void **slot; 1956 equiv_class_label_t ecl = XNEW (struct equiv_class_label); 1957 1958 ecl->labels = labels; 1959 ecl->equivalence_class = equivalence_class; 1960 ecl->hashcode = bitmap_hash (labels); 1961 1962 slot = htab_find_slot_with_hash (table, ecl, 1963 ecl->hashcode, INSERT); 1964 gcc_assert (!*slot); 1965 *slot = (void *) ecl; 1966 } 1967 1968 /* Perform offline variable substitution. 1969 1970 This is a worst case quadratic time way of identifying variables 1971 that must have equivalent points-to sets, including those caused by 1972 static cycles, and single entry subgraphs, in the constraint graph. 1973 1974 The technique is described in "Exploiting Pointer and Location 1975 Equivalence to Optimize Pointer Analysis. In the 14th International 1976 Static Analysis Symposium (SAS), August 2007." It is known as the 1977 "HU" algorithm, and is equivalent to value numbering the collapsed 1978 constraint graph including evaluating unions. 1979 1980 The general method of finding equivalence classes is as follows: 1981 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints. 1982 Initialize all non-REF nodes to be direct nodes. 1983 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh 1984 variable} 1985 For each constraint containing the dereference, we also do the same 1986 thing. 1987 1988 We then compute SCC's in the graph and unify nodes in the same SCC, 1989 including pts sets. 1990 1991 For each non-collapsed node x: 1992 Visit all unvisited explicit incoming edges. 1993 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y 1994 where y->x. 1995 Lookup the equivalence class for pts(x). 1996 If we found one, equivalence_class(x) = found class. 1997 Otherwise, equivalence_class(x) = new class, and new_class is 1998 added to the lookup table. 1999 2000 All direct nodes with the same equivalence class can be replaced 2001 with a single representative node. 2002 All unlabeled nodes (label == 0) are not pointers and all edges 2003 involving them can be eliminated. 2004 We perform these optimizations during rewrite_constraints 2005 2006 In addition to pointer equivalence class finding, we also perform 2007 location equivalence class finding. This is the set of variables 2008 that always appear together in points-to sets. We use this to 2009 compress the size of the points-to sets. */ 2010 2011 /* Current maximum pointer equivalence class id. */ 2012 static int pointer_equiv_class; 2013 2014 /* Current maximum location equivalence class id. */ 2015 static int location_equiv_class; 2016 2017 /* Recursive routine to find strongly connected components in GRAPH, 2018 and label it's nodes with DFS numbers. */ 2019 2020 static void 2021 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n) 2022 { 2023 unsigned int i; 2024 bitmap_iterator bi; 2025 unsigned int my_dfs; 2026 2027 gcc_assert (si->node_mapping[n] == n); 2028 SET_BIT (si->visited, n); 2029 si->dfs[n] = si->current_index ++; 2030 my_dfs = si->dfs[n]; 2031 2032 /* Visit all the successors. */ 2033 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi) 2034 { 2035 unsigned int w = si->node_mapping[i]; 2036 2037 if (TEST_BIT (si->deleted, w)) 2038 continue; 2039 2040 if (!TEST_BIT (si->visited, w)) 2041 condense_visit (graph, si, w); 2042 { 2043 unsigned int t = si->node_mapping[w]; 2044 unsigned int nnode = si->node_mapping[n]; 2045 gcc_assert (nnode == n); 2046 2047 if (si->dfs[t] < si->dfs[nnode]) 2048 si->dfs[n] = si->dfs[t]; 2049 } 2050 } 2051 2052 /* Visit all the implicit predecessors. */ 2053 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi) 2054 { 2055 unsigned int w = si->node_mapping[i]; 2056 2057 if (TEST_BIT (si->deleted, w)) 2058 continue; 2059 2060 if (!TEST_BIT (si->visited, w)) 2061 condense_visit (graph, si, w); 2062 { 2063 unsigned int t = si->node_mapping[w]; 2064 unsigned int nnode = si->node_mapping[n]; 2065 gcc_assert (nnode == n); 2066 2067 if (si->dfs[t] < si->dfs[nnode]) 2068 si->dfs[n] = si->dfs[t]; 2069 } 2070 } 2071 2072 /* See if any components have been identified. */ 2073 if (si->dfs[n] == my_dfs) 2074 { 2075 while (VEC_length (unsigned, si->scc_stack) != 0 2076 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs) 2077 { 2078 unsigned int w = VEC_pop (unsigned, si->scc_stack); 2079 si->node_mapping[w] = n; 2080 2081 if (!TEST_BIT (graph->direct_nodes, w)) 2082 RESET_BIT (graph->direct_nodes, n); 2083 2084 /* Unify our nodes. */ 2085 if (graph->preds[w]) 2086 { 2087 if (!graph->preds[n]) 2088 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack); 2089 bitmap_ior_into (graph->preds[n], graph->preds[w]); 2090 } 2091 if (graph->implicit_preds[w]) 2092 { 2093 if (!graph->implicit_preds[n]) 2094 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack); 2095 bitmap_ior_into (graph->implicit_preds[n], 2096 graph->implicit_preds[w]); 2097 } 2098 if (graph->points_to[w]) 2099 { 2100 if (!graph->points_to[n]) 2101 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack); 2102 bitmap_ior_into (graph->points_to[n], 2103 graph->points_to[w]); 2104 } 2105 } 2106 SET_BIT (si->deleted, n); 2107 } 2108 else 2109 VEC_safe_push (unsigned, heap, si->scc_stack, n); 2110 } 2111 2112 /* Label pointer equivalences. */ 2113 2114 static void 2115 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n) 2116 { 2117 unsigned int i; 2118 bitmap_iterator bi; 2119 SET_BIT (si->visited, n); 2120 2121 if (!graph->points_to[n]) 2122 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack); 2123 2124 /* Label and union our incoming edges's points to sets. */ 2125 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi) 2126 { 2127 unsigned int w = si->node_mapping[i]; 2128 if (!TEST_BIT (si->visited, w)) 2129 label_visit (graph, si, w); 2130 2131 /* Skip unused edges */ 2132 if (w == n || graph->pointer_label[w] == 0) 2133 continue; 2134 2135 if (graph->points_to[w]) 2136 bitmap_ior_into(graph->points_to[n], graph->points_to[w]); 2137 } 2138 /* Indirect nodes get fresh variables. */ 2139 if (!TEST_BIT (graph->direct_nodes, n)) 2140 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n); 2141 2142 if (!bitmap_empty_p (graph->points_to[n])) 2143 { 2144 bitmap ref_points_to; 2145 unsigned int label = equiv_class_lookup (pointer_equiv_class_table, 2146 graph->points_to[n], 2147 &ref_points_to); 2148 if (!label) 2149 { 2150 label = pointer_equiv_class++; 2151 equiv_class_add (pointer_equiv_class_table, 2152 label, graph->points_to[n]); 2153 } 2154 else 2155 { 2156 BITMAP_FREE (graph->points_to[n]); 2157 graph->points_to[n] = ref_points_to; 2158 } 2159 graph->pointer_label[n] = label; 2160 } 2161 } 2162 2163 /* Perform offline variable substitution, discovering equivalence 2164 classes, and eliminating non-pointer variables. */ 2165 2166 static struct scc_info * 2167 perform_var_substitution (constraint_graph_t graph) 2168 { 2169 unsigned int i; 2170 unsigned int size = graph->size; 2171 struct scc_info *si = init_scc_info (size); 2172 2173 bitmap_obstack_initialize (&iteration_obstack); 2174 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash, 2175 equiv_class_label_eq, free); 2176 location_equiv_class_table = htab_create (511, equiv_class_label_hash, 2177 equiv_class_label_eq, free); 2178 pointer_equiv_class = 1; 2179 location_equiv_class = 1; 2180 2181 /* Condense the nodes, which means to find SCC's, count incoming 2182 predecessors, and unite nodes in SCC's. */ 2183 for (i = 0; i < FIRST_REF_NODE; i++) 2184 if (!TEST_BIT (si->visited, si->node_mapping[i])) 2185 condense_visit (graph, si, si->node_mapping[i]); 2186 2187 sbitmap_zero (si->visited); 2188 /* Actually the label the nodes for pointer equivalences */ 2189 for (i = 0; i < FIRST_REF_NODE; i++) 2190 if (!TEST_BIT (si->visited, si->node_mapping[i])) 2191 label_visit (graph, si, si->node_mapping[i]); 2192 2193 /* Calculate location equivalence labels. */ 2194 for (i = 0; i < FIRST_REF_NODE; i++) 2195 { 2196 bitmap pointed_by; 2197 bitmap_iterator bi; 2198 unsigned int j; 2199 unsigned int label; 2200 2201 if (!graph->pointed_by[i]) 2202 continue; 2203 pointed_by = BITMAP_ALLOC (&iteration_obstack); 2204 2205 /* Translate the pointed-by mapping for pointer equivalence 2206 labels. */ 2207 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi) 2208 { 2209 bitmap_set_bit (pointed_by, 2210 graph->pointer_label[si->node_mapping[j]]); 2211 } 2212 /* The original pointed_by is now dead. */ 2213 BITMAP_FREE (graph->pointed_by[i]); 2214 2215 /* Look up the location equivalence label if one exists, or make 2216 one otherwise. */ 2217 label = equiv_class_lookup (location_equiv_class_table, 2218 pointed_by, NULL); 2219 if (label == 0) 2220 { 2221 label = location_equiv_class++; 2222 equiv_class_add (location_equiv_class_table, 2223 label, pointed_by); 2224 } 2225 else 2226 { 2227 if (dump_file && (dump_flags & TDF_DETAILS)) 2228 fprintf (dump_file, "Found location equivalence for node %s\n", 2229 get_varinfo (i)->name); 2230 BITMAP_FREE (pointed_by); 2231 } 2232 graph->loc_label[i] = label; 2233 2234 } 2235 2236 if (dump_file && (dump_flags & TDF_DETAILS)) 2237 for (i = 0; i < FIRST_REF_NODE; i++) 2238 { 2239 bool direct_node = TEST_BIT (graph->direct_nodes, i); 2240 fprintf (dump_file, 2241 "Equivalence classes for %s node id %d:%s are pointer: %d" 2242 ", location:%d\n", 2243 direct_node ? "Direct node" : "Indirect node", i, 2244 get_varinfo (i)->name, 2245 graph->pointer_label[si->node_mapping[i]], 2246 graph->loc_label[si->node_mapping[i]]); 2247 } 2248 2249 /* Quickly eliminate our non-pointer variables. */ 2250 2251 for (i = 0; i < FIRST_REF_NODE; i++) 2252 { 2253 unsigned int node = si->node_mapping[i]; 2254 2255 if (graph->pointer_label[node] == 0) 2256 { 2257 if (dump_file && (dump_flags & TDF_DETAILS)) 2258 fprintf (dump_file, 2259 "%s is a non-pointer variable, eliminating edges.\n", 2260 get_varinfo (node)->name); 2261 stats.nonpointer_vars++; 2262 clear_edges_for_node (graph, node); 2263 } 2264 } 2265 2266 return si; 2267 } 2268 2269 /* Free information that was only necessary for variable 2270 substitution. */ 2271 2272 static void 2273 free_var_substitution_info (struct scc_info *si) 2274 { 2275 free_scc_info (si); 2276 free (graph->pointer_label); 2277 free (graph->loc_label); 2278 free (graph->pointed_by); 2279 free (graph->points_to); 2280 free (graph->eq_rep); 2281 sbitmap_free (graph->direct_nodes); 2282 htab_delete (pointer_equiv_class_table); 2283 htab_delete (location_equiv_class_table); 2284 bitmap_obstack_release (&iteration_obstack); 2285 } 2286 2287 /* Return an existing node that is equivalent to NODE, which has 2288 equivalence class LABEL, if one exists. Return NODE otherwise. */ 2289 2290 static unsigned int 2291 find_equivalent_node (constraint_graph_t graph, 2292 unsigned int node, unsigned int label) 2293 { 2294 /* If the address version of this variable is unused, we can 2295 substitute it for anything else with the same label. 2296 Otherwise, we know the pointers are equivalent, but not the 2297 locations, and we can unite them later. */ 2298 2299 if (!bitmap_bit_p (graph->address_taken, node)) 2300 { 2301 gcc_assert (label < graph->size); 2302 2303 if (graph->eq_rep[label] != -1) 2304 { 2305 /* Unify the two variables since we know they are equivalent. */ 2306 if (unite (graph->eq_rep[label], node)) 2307 unify_nodes (graph, graph->eq_rep[label], node, false); 2308 return graph->eq_rep[label]; 2309 } 2310 else 2311 { 2312 graph->eq_rep[label] = node; 2313 graph->pe_rep[label] = node; 2314 } 2315 } 2316 else 2317 { 2318 gcc_assert (label < graph->size); 2319 graph->pe[node] = label; 2320 if (graph->pe_rep[label] == -1) 2321 graph->pe_rep[label] = node; 2322 } 2323 2324 return node; 2325 } 2326 2327 /* Unite pointer equivalent but not location equivalent nodes in 2328 GRAPH. This may only be performed once variable substitution is 2329 finished. */ 2330 2331 static void 2332 unite_pointer_equivalences (constraint_graph_t graph) 2333 { 2334 unsigned int i; 2335 2336 /* Go through the pointer equivalences and unite them to their 2337 representative, if they aren't already. */ 2338 for (i = 0; i < FIRST_REF_NODE; i++) 2339 { 2340 unsigned int label = graph->pe[i]; 2341 if (label) 2342 { 2343 int label_rep = graph->pe_rep[label]; 2344 2345 if (label_rep == -1) 2346 continue; 2347 2348 label_rep = find (label_rep); 2349 if (label_rep >= 0 && unite (label_rep, find (i))) 2350 unify_nodes (graph, label_rep, i, false); 2351 } 2352 } 2353 } 2354 2355 /* Move complex constraints to the GRAPH nodes they belong to. */ 2356 2357 static void 2358 move_complex_constraints (constraint_graph_t graph) 2359 { 2360 int i; 2361 constraint_t c; 2362 2363 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c) 2364 { 2365 if (c) 2366 { 2367 struct constraint_expr lhs = c->lhs; 2368 struct constraint_expr rhs = c->rhs; 2369 2370 if (lhs.type == DEREF) 2371 { 2372 insert_into_complex (graph, lhs.var, c); 2373 } 2374 else if (rhs.type == DEREF) 2375 { 2376 if (!(get_varinfo (lhs.var)->is_special_var)) 2377 insert_into_complex (graph, rhs.var, c); 2378 } 2379 else if (rhs.type != ADDRESSOF && lhs.var > anything_id 2380 && (lhs.offset != 0 || rhs.offset != 0)) 2381 { 2382 insert_into_complex (graph, rhs.var, c); 2383 } 2384 } 2385 } 2386 } 2387 2388 2389 /* Optimize and rewrite complex constraints while performing 2390 collapsing of equivalent nodes. SI is the SCC_INFO that is the 2391 result of perform_variable_substitution. */ 2392 2393 static void 2394 rewrite_constraints (constraint_graph_t graph, 2395 struct scc_info *si) 2396 { 2397 int i; 2398 unsigned int j; 2399 constraint_t c; 2400 2401 for (j = 0; j < graph->size; j++) 2402 gcc_assert (find (j) == j); 2403 2404 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c) 2405 { 2406 struct constraint_expr lhs = c->lhs; 2407 struct constraint_expr rhs = c->rhs; 2408 unsigned int lhsvar = find (lhs.var); 2409 unsigned int rhsvar = find (rhs.var); 2410 unsigned int lhsnode, rhsnode; 2411 unsigned int lhslabel, rhslabel; 2412 2413 lhsnode = si->node_mapping[lhsvar]; 2414 rhsnode = si->node_mapping[rhsvar]; 2415 lhslabel = graph->pointer_label[lhsnode]; 2416 rhslabel = graph->pointer_label[rhsnode]; 2417 2418 /* See if it is really a non-pointer variable, and if so, ignore 2419 the constraint. */ 2420 if (lhslabel == 0) 2421 { 2422 if (dump_file && (dump_flags & TDF_DETAILS)) 2423 { 2424 2425 fprintf (dump_file, "%s is a non-pointer variable," 2426 "ignoring constraint:", 2427 get_varinfo (lhs.var)->name); 2428 dump_constraint (dump_file, c); 2429 fprintf (dump_file, "\n"); 2430 } 2431 VEC_replace (constraint_t, constraints, i, NULL); 2432 continue; 2433 } 2434 2435 if (rhslabel == 0) 2436 { 2437 if (dump_file && (dump_flags & TDF_DETAILS)) 2438 { 2439 2440 fprintf (dump_file, "%s is a non-pointer variable," 2441 "ignoring constraint:", 2442 get_varinfo (rhs.var)->name); 2443 dump_constraint (dump_file, c); 2444 fprintf (dump_file, "\n"); 2445 } 2446 VEC_replace (constraint_t, constraints, i, NULL); 2447 continue; 2448 } 2449 2450 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel); 2451 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel); 2452 c->lhs.var = lhsvar; 2453 c->rhs.var = rhsvar; 2454 2455 } 2456 } 2457 2458 /* Eliminate indirect cycles involving NODE. Return true if NODE was 2459 part of an SCC, false otherwise. */ 2460 2461 static bool 2462 eliminate_indirect_cycles (unsigned int node) 2463 { 2464 if (graph->indirect_cycles[node] != -1 2465 && !bitmap_empty_p (get_varinfo (node)->solution)) 2466 { 2467 unsigned int i; 2468 VEC(unsigned,heap) *queue = NULL; 2469 int queuepos; 2470 unsigned int to = find (graph->indirect_cycles[node]); 2471 bitmap_iterator bi; 2472 2473 /* We can't touch the solution set and call unify_nodes 2474 at the same time, because unify_nodes is going to do 2475 bitmap unions into it. */ 2476 2477 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi) 2478 { 2479 if (find (i) == i && i != to) 2480 { 2481 if (unite (to, i)) 2482 VEC_safe_push (unsigned, heap, queue, i); 2483 } 2484 } 2485 2486 for (queuepos = 0; 2487 VEC_iterate (unsigned, queue, queuepos, i); 2488 queuepos++) 2489 { 2490 unify_nodes (graph, to, i, true); 2491 } 2492 VEC_free (unsigned, heap, queue); 2493 return true; 2494 } 2495 return false; 2496 } 2497 2498 /* Solve the constraint graph GRAPH using our worklist solver. 2499 This is based on the PW* family of solvers from the "Efficient Field 2500 Sensitive Pointer Analysis for C" paper. 2501 It works by iterating over all the graph nodes, processing the complex 2502 constraints and propagating the copy constraints, until everything stops 2503 changed. This corresponds to steps 6-8 in the solving list given above. */ 2504 2505 static void 2506 solve_graph (constraint_graph_t graph) 2507 { 2508 unsigned int size = graph->size; 2509 unsigned int i; 2510 bitmap pts; 2511 2512 changed = BITMAP_ALLOC (NULL); 2513 2514 /* Mark all initial non-collapsed nodes as changed. */ 2515 for (i = 0; i < size; i++) 2516 { 2517 varinfo_t ivi = get_varinfo (i); 2518 if (find (i) == i && !bitmap_empty_p (ivi->solution) 2519 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i])) 2520 || VEC_length (constraint_t, graph->complex[i]) > 0)) 2521 bitmap_set_bit (changed, i); 2522 } 2523 2524 /* Allocate a bitmap to be used to store the changed bits. */ 2525 pts = BITMAP_ALLOC (&pta_obstack); 2526 2527 while (!bitmap_empty_p (changed)) 2528 { 2529 unsigned int i; 2530 struct topo_info *ti = init_topo_info (); 2531 stats.iterations++; 2532 2533 bitmap_obstack_initialize (&iteration_obstack); 2534 2535 compute_topo_order (graph, ti); 2536 2537 while (VEC_length (unsigned, ti->topo_order) != 0) 2538 { 2539 2540 i = VEC_pop (unsigned, ti->topo_order); 2541 2542 /* If this variable is not a representative, skip it. */ 2543 if (find (i) != i) 2544 continue; 2545 2546 /* In certain indirect cycle cases, we may merge this 2547 variable to another. */ 2548 if (eliminate_indirect_cycles (i) && find (i) != i) 2549 continue; 2550 2551 /* If the node has changed, we need to process the 2552 complex constraints and outgoing edges again. */ 2553 if (bitmap_clear_bit (changed, i)) 2554 { 2555 unsigned int j; 2556 constraint_t c; 2557 bitmap solution; 2558 VEC(constraint_t,heap) *complex = graph->complex[i]; 2559 varinfo_t vi = get_varinfo (i); 2560 bool solution_empty; 2561 2562 /* Compute the changed set of solution bits. */ 2563 if (vi->oldsolution) 2564 bitmap_and_compl (pts, vi->solution, vi->oldsolution); 2565 else 2566 bitmap_copy (pts, vi->solution); 2567 2568 if (bitmap_empty_p (pts)) 2569 continue; 2570 2571 if (vi->oldsolution) 2572 bitmap_ior_into (vi->oldsolution, pts); 2573 else 2574 { 2575 vi->oldsolution = BITMAP_ALLOC (&oldpta_obstack); 2576 bitmap_copy (vi->oldsolution, pts); 2577 } 2578 2579 solution = vi->solution; 2580 solution_empty = bitmap_empty_p (solution); 2581 2582 /* Process the complex constraints */ 2583 FOR_EACH_VEC_ELT (constraint_t, complex, j, c) 2584 { 2585 /* XXX: This is going to unsort the constraints in 2586 some cases, which will occasionally add duplicate 2587 constraints during unification. This does not 2588 affect correctness. */ 2589 c->lhs.var = find (c->lhs.var); 2590 c->rhs.var = find (c->rhs.var); 2591 2592 /* The only complex constraint that can change our 2593 solution to non-empty, given an empty solution, 2594 is a constraint where the lhs side is receiving 2595 some set from elsewhere. */ 2596 if (!solution_empty || c->lhs.type != DEREF) 2597 do_complex_constraint (graph, c, pts); 2598 } 2599 2600 solution_empty = bitmap_empty_p (solution); 2601 2602 if (!solution_empty) 2603 { 2604 bitmap_iterator bi; 2605 unsigned eff_escaped_id = find (escaped_id); 2606 2607 /* Propagate solution to all successors. */ 2608 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i], 2609 0, j, bi) 2610 { 2611 bitmap tmp; 2612 bool flag; 2613 2614 unsigned int to = find (j); 2615 tmp = get_varinfo (to)->solution; 2616 flag = false; 2617 2618 /* Don't try to propagate to ourselves. */ 2619 if (to == i) 2620 continue; 2621 2622 /* If we propagate from ESCAPED use ESCAPED as 2623 placeholder. */ 2624 if (i == eff_escaped_id) 2625 flag = bitmap_set_bit (tmp, escaped_id); 2626 else 2627 flag = set_union_with_increment (tmp, pts, 0); 2628 2629 if (flag) 2630 { 2631 get_varinfo (to)->solution = tmp; 2632 bitmap_set_bit (changed, to); 2633 } 2634 } 2635 } 2636 } 2637 } 2638 free_topo_info (ti); 2639 bitmap_obstack_release (&iteration_obstack); 2640 } 2641 2642 BITMAP_FREE (pts); 2643 BITMAP_FREE (changed); 2644 bitmap_obstack_release (&oldpta_obstack); 2645 } 2646 2647 /* Map from trees to variable infos. */ 2648 static struct pointer_map_t *vi_for_tree; 2649 2650 2651 /* Insert ID as the variable id for tree T in the vi_for_tree map. */ 2652 2653 static void 2654 insert_vi_for_tree (tree t, varinfo_t vi) 2655 { 2656 void **slot = pointer_map_insert (vi_for_tree, t); 2657 gcc_assert (vi); 2658 gcc_assert (*slot == NULL); 2659 *slot = vi; 2660 } 2661 2662 /* Find the variable info for tree T in VI_FOR_TREE. If T does not 2663 exist in the map, return NULL, otherwise, return the varinfo we found. */ 2664 2665 static varinfo_t 2666 lookup_vi_for_tree (tree t) 2667 { 2668 void **slot = pointer_map_contains (vi_for_tree, t); 2669 if (slot == NULL) 2670 return NULL; 2671 2672 return (varinfo_t) *slot; 2673 } 2674 2675 /* Return a printable name for DECL */ 2676 2677 static const char * 2678 alias_get_name (tree decl) 2679 { 2680 const char *res; 2681 char *temp; 2682 int num_printed = 0; 2683 2684 if (DECL_ASSEMBLER_NAME_SET_P (decl)) 2685 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)); 2686 else 2687 res= get_name (decl); 2688 if (res != NULL) 2689 return res; 2690 2691 res = "NULL"; 2692 if (!dump_file) 2693 return res; 2694 2695 if (TREE_CODE (decl) == SSA_NAME) 2696 { 2697 num_printed = asprintf (&temp, "%s_%u", 2698 alias_get_name (SSA_NAME_VAR (decl)), 2699 SSA_NAME_VERSION (decl)); 2700 } 2701 else if (DECL_P (decl)) 2702 { 2703 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl)); 2704 } 2705 if (num_printed > 0) 2706 { 2707 res = ggc_strdup (temp); 2708 free (temp); 2709 } 2710 return res; 2711 } 2712 2713 /* Find the variable id for tree T in the map. 2714 If T doesn't exist in the map, create an entry for it and return it. */ 2715 2716 static varinfo_t 2717 get_vi_for_tree (tree t) 2718 { 2719 void **slot = pointer_map_contains (vi_for_tree, t); 2720 if (slot == NULL) 2721 return get_varinfo (create_variable_info_for (t, alias_get_name (t))); 2722 2723 return (varinfo_t) *slot; 2724 } 2725 2726 /* Get a scalar constraint expression for a new temporary variable. */ 2727 2728 static struct constraint_expr 2729 new_scalar_tmp_constraint_exp (const char *name) 2730 { 2731 struct constraint_expr tmp; 2732 varinfo_t vi; 2733 2734 vi = new_var_info (NULL_TREE, name); 2735 vi->offset = 0; 2736 vi->size = -1; 2737 vi->fullsize = -1; 2738 vi->is_full_var = 1; 2739 2740 tmp.var = vi->id; 2741 tmp.type = SCALAR; 2742 tmp.offset = 0; 2743 2744 return tmp; 2745 } 2746 2747 /* Get a constraint expression vector from an SSA_VAR_P node. 2748 If address_p is true, the result will be taken its address of. */ 2749 2750 static void 2751 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p) 2752 { 2753 struct constraint_expr cexpr; 2754 varinfo_t vi; 2755 2756 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */ 2757 gcc_assert (SSA_VAR_P (t) || DECL_P (t)); 2758 2759 /* For parameters, get at the points-to set for the actual parm 2760 decl. */ 2761 if (TREE_CODE (t) == SSA_NAME 2762 && (TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL 2763 || TREE_CODE (SSA_NAME_VAR (t)) == RESULT_DECL) 2764 && SSA_NAME_IS_DEFAULT_DEF (t)) 2765 { 2766 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p); 2767 return; 2768 } 2769 2770 /* For global variables resort to the alias target. */ 2771 if (TREE_CODE (t) == VAR_DECL 2772 && (TREE_STATIC (t) || DECL_EXTERNAL (t))) 2773 { 2774 struct varpool_node *node = varpool_get_node (t); 2775 if (node && node->alias) 2776 { 2777 node = varpool_variable_node (node, NULL); 2778 t = node->decl; 2779 } 2780 } 2781 2782 vi = get_vi_for_tree (t); 2783 cexpr.var = vi->id; 2784 cexpr.type = SCALAR; 2785 cexpr.offset = 0; 2786 /* If we determine the result is "anything", and we know this is readonly, 2787 say it points to readonly memory instead. */ 2788 if (cexpr.var == anything_id && TREE_READONLY (t)) 2789 { 2790 gcc_unreachable (); 2791 cexpr.type = ADDRESSOF; 2792 cexpr.var = readonly_id; 2793 } 2794 2795 /* If we are not taking the address of the constraint expr, add all 2796 sub-fiels of the variable as well. */ 2797 if (!address_p 2798 && !vi->is_full_var) 2799 { 2800 for (; vi; vi = vi->next) 2801 { 2802 cexpr.var = vi->id; 2803 VEC_safe_push (ce_s, heap, *results, &cexpr); 2804 } 2805 return; 2806 } 2807 2808 VEC_safe_push (ce_s, heap, *results, &cexpr); 2809 } 2810 2811 /* Process constraint T, performing various simplifications and then 2812 adding it to our list of overall constraints. */ 2813 2814 static void 2815 process_constraint (constraint_t t) 2816 { 2817 struct constraint_expr rhs = t->rhs; 2818 struct constraint_expr lhs = t->lhs; 2819 2820 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap)); 2821 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap)); 2822 2823 /* If we didn't get any useful constraint from the lhs we get 2824 &ANYTHING as fallback from get_constraint_for. Deal with 2825 it here by turning it into *ANYTHING. */ 2826 if (lhs.type == ADDRESSOF 2827 && lhs.var == anything_id) 2828 lhs.type = DEREF; 2829 2830 /* ADDRESSOF on the lhs is invalid. */ 2831 gcc_assert (lhs.type != ADDRESSOF); 2832 2833 /* We shouldn't add constraints from things that cannot have pointers. 2834 It's not completely trivial to avoid in the callers, so do it here. */ 2835 if (rhs.type != ADDRESSOF 2836 && !get_varinfo (rhs.var)->may_have_pointers) 2837 return; 2838 2839 /* Likewise adding to the solution of a non-pointer var isn't useful. */ 2840 if (!get_varinfo (lhs.var)->may_have_pointers) 2841 return; 2842 2843 /* This can happen in our IR with things like n->a = *p */ 2844 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id) 2845 { 2846 /* Split into tmp = *rhs, *lhs = tmp */ 2847 struct constraint_expr tmplhs; 2848 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp"); 2849 process_constraint (new_constraint (tmplhs, rhs)); 2850 process_constraint (new_constraint (lhs, tmplhs)); 2851 } 2852 else if (rhs.type == ADDRESSOF && lhs.type == DEREF) 2853 { 2854 /* Split into tmp = &rhs, *lhs = tmp */ 2855 struct constraint_expr tmplhs; 2856 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp"); 2857 process_constraint (new_constraint (tmplhs, rhs)); 2858 process_constraint (new_constraint (lhs, tmplhs)); 2859 } 2860 else 2861 { 2862 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0); 2863 VEC_safe_push (constraint_t, heap, constraints, t); 2864 } 2865 } 2866 2867 2868 /* Return the position, in bits, of FIELD_DECL from the beginning of its 2869 structure. */ 2870 2871 static HOST_WIDE_INT 2872 bitpos_of_field (const tree fdecl) 2873 { 2874 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0) 2875 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0)) 2876 return -1; 2877 2878 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * BITS_PER_UNIT 2879 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl))); 2880 } 2881 2882 2883 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the 2884 resulting constraint expressions in *RESULTS. */ 2885 2886 static void 2887 get_constraint_for_ptr_offset (tree ptr, tree offset, 2888 VEC (ce_s, heap) **results) 2889 { 2890 struct constraint_expr c; 2891 unsigned int j, n; 2892 HOST_WIDE_INT rhsoffset; 2893 2894 /* If we do not do field-sensitive PTA adding offsets to pointers 2895 does not change the points-to solution. */ 2896 if (!use_field_sensitive) 2897 { 2898 get_constraint_for_rhs (ptr, results); 2899 return; 2900 } 2901 2902 /* If the offset is not a non-negative integer constant that fits 2903 in a HOST_WIDE_INT, we have to fall back to a conservative 2904 solution which includes all sub-fields of all pointed-to 2905 variables of ptr. */ 2906 if (offset == NULL_TREE 2907 || TREE_CODE (offset) != INTEGER_CST) 2908 rhsoffset = UNKNOWN_OFFSET; 2909 else 2910 { 2911 /* Sign-extend the offset. */ 2912 double_int soffset 2913 = double_int_sext (tree_to_double_int (offset), 2914 TYPE_PRECISION (TREE_TYPE (offset))); 2915 if (!double_int_fits_in_shwi_p (soffset)) 2916 rhsoffset = UNKNOWN_OFFSET; 2917 else 2918 { 2919 /* Make sure the bit-offset also fits. */ 2920 HOST_WIDE_INT rhsunitoffset = soffset.low; 2921 rhsoffset = rhsunitoffset * BITS_PER_UNIT; 2922 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT) 2923 rhsoffset = UNKNOWN_OFFSET; 2924 } 2925 } 2926 2927 get_constraint_for_rhs (ptr, results); 2928 if (rhsoffset == 0) 2929 return; 2930 2931 /* As we are eventually appending to the solution do not use 2932 VEC_iterate here. */ 2933 n = VEC_length (ce_s, *results); 2934 for (j = 0; j < n; j++) 2935 { 2936 varinfo_t curr; 2937 c = *VEC_index (ce_s, *results, j); 2938 curr = get_varinfo (c.var); 2939 2940 if (c.type == ADDRESSOF 2941 /* If this varinfo represents a full variable just use it. */ 2942 && curr->is_full_var) 2943 c.offset = 0; 2944 else if (c.type == ADDRESSOF 2945 /* If we do not know the offset add all subfields. */ 2946 && rhsoffset == UNKNOWN_OFFSET) 2947 { 2948 varinfo_t temp = lookup_vi_for_tree (curr->decl); 2949 do 2950 { 2951 struct constraint_expr c2; 2952 c2.var = temp->id; 2953 c2.type = ADDRESSOF; 2954 c2.offset = 0; 2955 if (c2.var != c.var) 2956 VEC_safe_push (ce_s, heap, *results, &c2); 2957 temp = temp->next; 2958 } 2959 while (temp); 2960 } 2961 else if (c.type == ADDRESSOF) 2962 { 2963 varinfo_t temp; 2964 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset; 2965 2966 /* Search the sub-field which overlaps with the 2967 pointed-to offset. If the result is outside of the variable 2968 we have to provide a conservative result, as the variable is 2969 still reachable from the resulting pointer (even though it 2970 technically cannot point to anything). The last and first 2971 sub-fields are such conservative results. 2972 ??? If we always had a sub-field for &object + 1 then 2973 we could represent this in a more precise way. */ 2974 if (rhsoffset < 0 2975 && curr->offset < offset) 2976 offset = 0; 2977 temp = first_or_preceding_vi_for_offset (curr, offset); 2978 2979 /* If the found variable is not exactly at the pointed to 2980 result, we have to include the next variable in the 2981 solution as well. Otherwise two increments by offset / 2 2982 do not result in the same or a conservative superset 2983 solution. */ 2984 if (temp->offset != offset 2985 && temp->next != NULL) 2986 { 2987 struct constraint_expr c2; 2988 c2.var = temp->next->id; 2989 c2.type = ADDRESSOF; 2990 c2.offset = 0; 2991 VEC_safe_push (ce_s, heap, *results, &c2); 2992 } 2993 c.var = temp->id; 2994 c.offset = 0; 2995 } 2996 else 2997 c.offset = rhsoffset; 2998 2999 VEC_replace (ce_s, *results, j, &c); 3000 } 3001 } 3002 3003 3004 /* Given a COMPONENT_REF T, return the constraint_expr vector for it. 3005 If address_p is true the result will be taken its address of. 3006 If lhs_p is true then the constraint expression is assumed to be used 3007 as the lhs. */ 3008 3009 static void 3010 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results, 3011 bool address_p, bool lhs_p) 3012 { 3013 tree orig_t = t; 3014 HOST_WIDE_INT bitsize = -1; 3015 HOST_WIDE_INT bitmaxsize = -1; 3016 HOST_WIDE_INT bitpos; 3017 tree forzero; 3018 struct constraint_expr *result; 3019 3020 /* Some people like to do cute things like take the address of 3021 &0->a.b */ 3022 forzero = t; 3023 while (handled_component_p (forzero) 3024 || INDIRECT_REF_P (forzero) 3025 || TREE_CODE (forzero) == MEM_REF) 3026 forzero = TREE_OPERAND (forzero, 0); 3027 3028 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero)) 3029 { 3030 struct constraint_expr temp; 3031 3032 temp.offset = 0; 3033 temp.var = integer_id; 3034 temp.type = SCALAR; 3035 VEC_safe_push (ce_s, heap, *results, &temp); 3036 return; 3037 } 3038 3039 /* Handle type-punning through unions. If we are extracting a pointer 3040 from a union via a possibly type-punning access that pointer 3041 points to anything, similar to a conversion of an integer to 3042 a pointer. */ 3043 if (!lhs_p) 3044 { 3045 tree u; 3046 for (u = t; 3047 TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF; 3048 u = TREE_OPERAND (u, 0)) 3049 if (TREE_CODE (u) == COMPONENT_REF 3050 && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE) 3051 { 3052 struct constraint_expr temp; 3053 3054 temp.offset = 0; 3055 temp.var = anything_id; 3056 temp.type = ADDRESSOF; 3057 VEC_safe_push (ce_s, heap, *results, &temp); 3058 return; 3059 } 3060 } 3061 3062 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize); 3063 3064 /* Pretend to take the address of the base, we'll take care of 3065 adding the required subset of sub-fields below. */ 3066 get_constraint_for_1 (t, results, true, lhs_p); 3067 gcc_assert (VEC_length (ce_s, *results) == 1); 3068 result = VEC_last (ce_s, *results); 3069 3070 if (result->type == SCALAR 3071 && get_varinfo (result->var)->is_full_var) 3072 /* For single-field vars do not bother about the offset. */ 3073 result->offset = 0; 3074 else if (result->type == SCALAR) 3075 { 3076 /* In languages like C, you can access one past the end of an 3077 array. You aren't allowed to dereference it, so we can 3078 ignore this constraint. When we handle pointer subtraction, 3079 we may have to do something cute here. */ 3080 3081 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize 3082 && bitmaxsize != 0) 3083 { 3084 /* It's also not true that the constraint will actually start at the 3085 right offset, it may start in some padding. We only care about 3086 setting the constraint to the first actual field it touches, so 3087 walk to find it. */ 3088 struct constraint_expr cexpr = *result; 3089 varinfo_t curr; 3090 VEC_pop (ce_s, *results); 3091 cexpr.offset = 0; 3092 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next) 3093 { 3094 if (ranges_overlap_p (curr->offset, curr->size, 3095 bitpos, bitmaxsize)) 3096 { 3097 cexpr.var = curr->id; 3098 VEC_safe_push (ce_s, heap, *results, &cexpr); 3099 if (address_p) 3100 break; 3101 } 3102 } 3103 /* If we are going to take the address of this field then 3104 to be able to compute reachability correctly add at least 3105 the last field of the variable. */ 3106 if (address_p 3107 && VEC_length (ce_s, *results) == 0) 3108 { 3109 curr = get_varinfo (cexpr.var); 3110 while (curr->next != NULL) 3111 curr = curr->next; 3112 cexpr.var = curr->id; 3113 VEC_safe_push (ce_s, heap, *results, &cexpr); 3114 } 3115 else if (VEC_length (ce_s, *results) == 0) 3116 /* Assert that we found *some* field there. The user couldn't be 3117 accessing *only* padding. */ 3118 /* Still the user could access one past the end of an array 3119 embedded in a struct resulting in accessing *only* padding. */ 3120 /* Or accessing only padding via type-punning to a type 3121 that has a filed just in padding space. */ 3122 { 3123 cexpr.type = SCALAR; 3124 cexpr.var = anything_id; 3125 cexpr.offset = 0; 3126 VEC_safe_push (ce_s, heap, *results, &cexpr); 3127 } 3128 } 3129 else if (bitmaxsize == 0) 3130 { 3131 if (dump_file && (dump_flags & TDF_DETAILS)) 3132 fprintf (dump_file, "Access to zero-sized part of variable," 3133 "ignoring\n"); 3134 } 3135 else 3136 if (dump_file && (dump_flags & TDF_DETAILS)) 3137 fprintf (dump_file, "Access to past the end of variable, ignoring\n"); 3138 } 3139 else if (result->type == DEREF) 3140 { 3141 /* If we do not know exactly where the access goes say so. Note 3142 that only for non-structure accesses we know that we access 3143 at most one subfiled of any variable. */ 3144 if (bitpos == -1 3145 || bitsize != bitmaxsize 3146 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t)) 3147 || result->offset == UNKNOWN_OFFSET) 3148 result->offset = UNKNOWN_OFFSET; 3149 else 3150 result->offset += bitpos; 3151 } 3152 else if (result->type == ADDRESSOF) 3153 { 3154 /* We can end up here for component references on a 3155 VIEW_CONVERT_EXPR <>(&foobar). */ 3156 result->type = SCALAR; 3157 result->var = anything_id; 3158 result->offset = 0; 3159 } 3160 else 3161 gcc_unreachable (); 3162 } 3163 3164 3165 /* Dereference the constraint expression CONS, and return the result. 3166 DEREF (ADDRESSOF) = SCALAR 3167 DEREF (SCALAR) = DEREF 3168 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp)) 3169 This is needed so that we can handle dereferencing DEREF constraints. */ 3170 3171 static void 3172 do_deref (VEC (ce_s, heap) **constraints) 3173 { 3174 struct constraint_expr *c; 3175 unsigned int i = 0; 3176 3177 FOR_EACH_VEC_ELT (ce_s, *constraints, i, c) 3178 { 3179 if (c->type == SCALAR) 3180 c->type = DEREF; 3181 else if (c->type == ADDRESSOF) 3182 c->type = SCALAR; 3183 else if (c->type == DEREF) 3184 { 3185 struct constraint_expr tmplhs; 3186 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp"); 3187 process_constraint (new_constraint (tmplhs, *c)); 3188 c->var = tmplhs.var; 3189 } 3190 else 3191 gcc_unreachable (); 3192 } 3193 } 3194 3195 /* Given a tree T, return the constraint expression for taking the 3196 address of it. */ 3197 3198 static void 3199 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results) 3200 { 3201 struct constraint_expr *c; 3202 unsigned int i; 3203 3204 get_constraint_for_1 (t, results, true, true); 3205 3206 FOR_EACH_VEC_ELT (ce_s, *results, i, c) 3207 { 3208 if (c->type == DEREF) 3209 c->type = SCALAR; 3210 else 3211 c->type = ADDRESSOF; 3212 } 3213 } 3214 3215 /* Given a tree T, return the constraint expression for it. */ 3216 3217 static void 3218 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p, 3219 bool lhs_p) 3220 { 3221 struct constraint_expr temp; 3222 3223 /* x = integer is all glommed to a single variable, which doesn't 3224 point to anything by itself. That is, of course, unless it is an 3225 integer constant being treated as a pointer, in which case, we 3226 will return that this is really the addressof anything. This 3227 happens below, since it will fall into the default case. The only 3228 case we know something about an integer treated like a pointer is 3229 when it is the NULL pointer, and then we just say it points to 3230 NULL. 3231 3232 Do not do that if -fno-delete-null-pointer-checks though, because 3233 in that case *NULL does not fail, so it _should_ alias *anything. 3234 It is not worth adding a new option or renaming the existing one, 3235 since this case is relatively obscure. */ 3236 if ((TREE_CODE (t) == INTEGER_CST 3237 && integer_zerop (t)) 3238 /* The only valid CONSTRUCTORs in gimple with pointer typed 3239 elements are zero-initializer. But in IPA mode we also 3240 process global initializers, so verify at least. */ 3241 || (TREE_CODE (t) == CONSTRUCTOR 3242 && CONSTRUCTOR_NELTS (t) == 0)) 3243 { 3244 if (flag_delete_null_pointer_checks) 3245 temp.var = nothing_id; 3246 else 3247 temp.var = nonlocal_id; 3248 temp.type = ADDRESSOF; 3249 temp.offset = 0; 3250 VEC_safe_push (ce_s, heap, *results, &temp); 3251 return; 3252 } 3253 3254 /* String constants are read-only. */ 3255 if (TREE_CODE (t) == STRING_CST) 3256 { 3257 temp.var = readonly_id; 3258 temp.type = SCALAR; 3259 temp.offset = 0; 3260 VEC_safe_push (ce_s, heap, *results, &temp); 3261 return; 3262 } 3263 3264 switch (TREE_CODE_CLASS (TREE_CODE (t))) 3265 { 3266 case tcc_expression: 3267 { 3268 switch (TREE_CODE (t)) 3269 { 3270 case ADDR_EXPR: 3271 get_constraint_for_address_of (TREE_OPERAND (t, 0), results); 3272 return; 3273 default:; 3274 } 3275 break; 3276 } 3277 case tcc_reference: 3278 { 3279 switch (TREE_CODE (t)) 3280 { 3281 case MEM_REF: 3282 { 3283 struct constraint_expr cs; 3284 varinfo_t vi, curr; 3285 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0), 3286 TREE_OPERAND (t, 1), results); 3287 do_deref (results); 3288 3289 /* If we are not taking the address then make sure to process 3290 all subvariables we might access. */ 3291 if (address_p) 3292 return; 3293 3294 cs = *VEC_last (ce_s, *results); 3295 if (cs.type == DEREF 3296 && type_can_have_subvars (TREE_TYPE (t))) 3297 { 3298 /* For dereferences this means we have to defer it 3299 to solving time. */ 3300 VEC_last (ce_s, *results)->offset = UNKNOWN_OFFSET; 3301 return; 3302 } 3303 if (cs.type != SCALAR) 3304 return; 3305 3306 vi = get_varinfo (cs.var); 3307 curr = vi->next; 3308 if (!vi->is_full_var 3309 && curr) 3310 { 3311 unsigned HOST_WIDE_INT size; 3312 if (host_integerp (TYPE_SIZE (TREE_TYPE (t)), 1)) 3313 size = TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (t))); 3314 else 3315 size = -1; 3316 for (; curr; curr = curr->next) 3317 { 3318 if (curr->offset - vi->offset < size) 3319 { 3320 cs.var = curr->id; 3321 VEC_safe_push (ce_s, heap, *results, &cs); 3322 } 3323 else 3324 break; 3325 } 3326 } 3327 return; 3328 } 3329 case ARRAY_REF: 3330 case ARRAY_RANGE_REF: 3331 case COMPONENT_REF: 3332 get_constraint_for_component_ref (t, results, address_p, lhs_p); 3333 return; 3334 case VIEW_CONVERT_EXPR: 3335 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p, 3336 lhs_p); 3337 return; 3338 /* We are missing handling for TARGET_MEM_REF here. */ 3339 default:; 3340 } 3341 break; 3342 } 3343 case tcc_exceptional: 3344 { 3345 switch (TREE_CODE (t)) 3346 { 3347 case SSA_NAME: 3348 { 3349 get_constraint_for_ssa_var (t, results, address_p); 3350 return; 3351 } 3352 case CONSTRUCTOR: 3353 { 3354 unsigned int i; 3355 tree val; 3356 VEC (ce_s, heap) *tmp = NULL; 3357 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val) 3358 { 3359 struct constraint_expr *rhsp; 3360 unsigned j; 3361 get_constraint_for_1 (val, &tmp, address_p, lhs_p); 3362 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp) 3363 VEC_safe_push (ce_s, heap, *results, rhsp); 3364 VEC_truncate (ce_s, tmp, 0); 3365 } 3366 VEC_free (ce_s, heap, tmp); 3367 /* We do not know whether the constructor was complete, 3368 so technically we have to add &NOTHING or &ANYTHING 3369 like we do for an empty constructor as well. */ 3370 return; 3371 } 3372 default:; 3373 } 3374 break; 3375 } 3376 case tcc_declaration: 3377 { 3378 get_constraint_for_ssa_var (t, results, address_p); 3379 return; 3380 } 3381 case tcc_constant: 3382 { 3383 /* We cannot refer to automatic variables through constants. */ 3384 temp.type = ADDRESSOF; 3385 temp.var = nonlocal_id; 3386 temp.offset = 0; 3387 VEC_safe_push (ce_s, heap, *results, &temp); 3388 return; 3389 } 3390 default:; 3391 } 3392 3393 /* The default fallback is a constraint from anything. */ 3394 temp.type = ADDRESSOF; 3395 temp.var = anything_id; 3396 temp.offset = 0; 3397 VEC_safe_push (ce_s, heap, *results, &temp); 3398 } 3399 3400 /* Given a gimple tree T, return the constraint expression vector for it. */ 3401 3402 static void 3403 get_constraint_for (tree t, VEC (ce_s, heap) **results) 3404 { 3405 gcc_assert (VEC_length (ce_s, *results) == 0); 3406 3407 get_constraint_for_1 (t, results, false, true); 3408 } 3409 3410 /* Given a gimple tree T, return the constraint expression vector for it 3411 to be used as the rhs of a constraint. */ 3412 3413 static void 3414 get_constraint_for_rhs (tree t, VEC (ce_s, heap) **results) 3415 { 3416 gcc_assert (VEC_length (ce_s, *results) == 0); 3417 3418 get_constraint_for_1 (t, results, false, false); 3419 } 3420 3421 3422 /* Efficiently generates constraints from all entries in *RHSC to all 3423 entries in *LHSC. */ 3424 3425 static void 3426 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc) 3427 { 3428 struct constraint_expr *lhsp, *rhsp; 3429 unsigned i, j; 3430 3431 if (VEC_length (ce_s, lhsc) <= 1 3432 || VEC_length (ce_s, rhsc) <= 1) 3433 { 3434 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp) 3435 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp) 3436 process_constraint (new_constraint (*lhsp, *rhsp)); 3437 } 3438 else 3439 { 3440 struct constraint_expr tmp; 3441 tmp = new_scalar_tmp_constraint_exp ("allalltmp"); 3442 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp) 3443 process_constraint (new_constraint (tmp, *rhsp)); 3444 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp) 3445 process_constraint (new_constraint (*lhsp, tmp)); 3446 } 3447 } 3448 3449 /* Handle aggregate copies by expanding into copies of the respective 3450 fields of the structures. */ 3451 3452 static void 3453 do_structure_copy (tree lhsop, tree rhsop) 3454 { 3455 struct constraint_expr *lhsp, *rhsp; 3456 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL; 3457 unsigned j; 3458 3459 get_constraint_for (lhsop, &lhsc); 3460 get_constraint_for_rhs (rhsop, &rhsc); 3461 lhsp = VEC_index (ce_s, lhsc, 0); 3462 rhsp = VEC_index (ce_s, rhsc, 0); 3463 if (lhsp->type == DEREF 3464 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id) 3465 || rhsp->type == DEREF) 3466 { 3467 if (lhsp->type == DEREF) 3468 { 3469 gcc_assert (VEC_length (ce_s, lhsc) == 1); 3470 lhsp->offset = UNKNOWN_OFFSET; 3471 } 3472 if (rhsp->type == DEREF) 3473 { 3474 gcc_assert (VEC_length (ce_s, rhsc) == 1); 3475 rhsp->offset = UNKNOWN_OFFSET; 3476 } 3477 process_all_all_constraints (lhsc, rhsc); 3478 } 3479 else if (lhsp->type == SCALAR 3480 && (rhsp->type == SCALAR 3481 || rhsp->type == ADDRESSOF)) 3482 { 3483 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset; 3484 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset; 3485 unsigned k = 0; 3486 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize); 3487 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize); 3488 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);) 3489 { 3490 varinfo_t lhsv, rhsv; 3491 rhsp = VEC_index (ce_s, rhsc, k); 3492 lhsv = get_varinfo (lhsp->var); 3493 rhsv = get_varinfo (rhsp->var); 3494 if (lhsv->may_have_pointers 3495 && (lhsv->is_full_var 3496 || rhsv->is_full_var 3497 || ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size, 3498 rhsv->offset + lhsoffset, rhsv->size))) 3499 process_constraint (new_constraint (*lhsp, *rhsp)); 3500 if (!rhsv->is_full_var 3501 && (lhsv->is_full_var 3502 || (lhsv->offset + rhsoffset + lhsv->size 3503 > rhsv->offset + lhsoffset + rhsv->size))) 3504 { 3505 ++k; 3506 if (k >= VEC_length (ce_s, rhsc)) 3507 break; 3508 } 3509 else 3510 ++j; 3511 } 3512 } 3513 else 3514 gcc_unreachable (); 3515 3516 VEC_free (ce_s, heap, lhsc); 3517 VEC_free (ce_s, heap, rhsc); 3518 } 3519 3520 /* Create constraints ID = { rhsc }. */ 3521 3522 static void 3523 make_constraints_to (unsigned id, VEC(ce_s, heap) *rhsc) 3524 { 3525 struct constraint_expr *c; 3526 struct constraint_expr includes; 3527 unsigned int j; 3528 3529 includes.var = id; 3530 includes.offset = 0; 3531 includes.type = SCALAR; 3532 3533 FOR_EACH_VEC_ELT (ce_s, rhsc, j, c) 3534 process_constraint (new_constraint (includes, *c)); 3535 } 3536 3537 /* Create a constraint ID = OP. */ 3538 3539 static void 3540 make_constraint_to (unsigned id, tree op) 3541 { 3542 VEC(ce_s, heap) *rhsc = NULL; 3543 get_constraint_for_rhs (op, &rhsc); 3544 make_constraints_to (id, rhsc); 3545 VEC_free (ce_s, heap, rhsc); 3546 } 3547 3548 /* Create a constraint ID = &FROM. */ 3549 3550 static void 3551 make_constraint_from (varinfo_t vi, int from) 3552 { 3553 struct constraint_expr lhs, rhs; 3554 3555 lhs.var = vi->id; 3556 lhs.offset = 0; 3557 lhs.type = SCALAR; 3558 3559 rhs.var = from; 3560 rhs.offset = 0; 3561 rhs.type = ADDRESSOF; 3562 process_constraint (new_constraint (lhs, rhs)); 3563 } 3564 3565 /* Create a constraint ID = FROM. */ 3566 3567 static void 3568 make_copy_constraint (varinfo_t vi, int from) 3569 { 3570 struct constraint_expr lhs, rhs; 3571 3572 lhs.var = vi->id; 3573 lhs.offset = 0; 3574 lhs.type = SCALAR; 3575 3576 rhs.var = from; 3577 rhs.offset = 0; 3578 rhs.type = SCALAR; 3579 process_constraint (new_constraint (lhs, rhs)); 3580 } 3581 3582 /* Make constraints necessary to make OP escape. */ 3583 3584 static void 3585 make_escape_constraint (tree op) 3586 { 3587 make_constraint_to (escaped_id, op); 3588 } 3589 3590 /* Add constraints to that the solution of VI is transitively closed. */ 3591 3592 static void 3593 make_transitive_closure_constraints (varinfo_t vi) 3594 { 3595 struct constraint_expr lhs, rhs; 3596 3597 /* VAR = *VAR; */ 3598 lhs.type = SCALAR; 3599 lhs.var = vi->id; 3600 lhs.offset = 0; 3601 rhs.type = DEREF; 3602 rhs.var = vi->id; 3603 rhs.offset = 0; 3604 process_constraint (new_constraint (lhs, rhs)); 3605 3606 /* VAR = VAR + UNKNOWN; */ 3607 lhs.type = SCALAR; 3608 lhs.var = vi->id; 3609 lhs.offset = 0; 3610 rhs.type = SCALAR; 3611 rhs.var = vi->id; 3612 rhs.offset = UNKNOWN_OFFSET; 3613 process_constraint (new_constraint (lhs, rhs)); 3614 } 3615 3616 /* Temporary storage for fake var decls. */ 3617 struct obstack fake_var_decl_obstack; 3618 3619 /* Build a fake VAR_DECL acting as referrer to a DECL_UID. */ 3620 3621 static tree 3622 build_fake_var_decl (tree type) 3623 { 3624 tree decl = (tree) XOBNEW (&fake_var_decl_obstack, struct tree_var_decl); 3625 memset (decl, 0, sizeof (struct tree_var_decl)); 3626 TREE_SET_CODE (decl, VAR_DECL); 3627 TREE_TYPE (decl) = type; 3628 DECL_UID (decl) = allocate_decl_uid (); 3629 SET_DECL_PT_UID (decl, -1); 3630 layout_decl (decl, 0); 3631 return decl; 3632 } 3633 3634 /* Create a new artificial heap variable with NAME. 3635 Return the created variable. */ 3636 3637 static varinfo_t 3638 make_heapvar (const char *name) 3639 { 3640 varinfo_t vi; 3641 tree heapvar; 3642 3643 heapvar = build_fake_var_decl (ptr_type_node); 3644 DECL_EXTERNAL (heapvar) = 1; 3645 3646 vi = new_var_info (heapvar, name); 3647 vi->is_artificial_var = true; 3648 vi->is_heap_var = true; 3649 vi->is_unknown_size_var = true; 3650 vi->offset = 0; 3651 vi->fullsize = ~0; 3652 vi->size = ~0; 3653 vi->is_full_var = true; 3654 insert_vi_for_tree (heapvar, vi); 3655 3656 return vi; 3657 } 3658 3659 /* Create a new artificial heap variable with NAME and make a 3660 constraint from it to LHS. Set flags according to a tag used 3661 for tracking restrict pointers. */ 3662 3663 static varinfo_t 3664 make_constraint_from_restrict (varinfo_t lhs, const char *name) 3665 { 3666 varinfo_t vi = make_heapvar (name); 3667 vi->is_global_var = 1; 3668 vi->may_have_pointers = 1; 3669 make_constraint_from (lhs, vi->id); 3670 return vi; 3671 } 3672 3673 /* Create a new artificial heap variable with NAME and make a 3674 constraint from it to LHS. Set flags according to a tag used 3675 for tracking restrict pointers and make the artificial heap 3676 point to global memory. */ 3677 3678 static varinfo_t 3679 make_constraint_from_global_restrict (varinfo_t lhs, const char *name) 3680 { 3681 varinfo_t vi = make_constraint_from_restrict (lhs, name); 3682 make_copy_constraint (vi, nonlocal_id); 3683 return vi; 3684 } 3685 3686 /* In IPA mode there are varinfos for different aspects of reach 3687 function designator. One for the points-to set of the return 3688 value, one for the variables that are clobbered by the function, 3689 one for its uses and one for each parameter (including a single 3690 glob for remaining variadic arguments). */ 3691 3692 enum { fi_clobbers = 1, fi_uses = 2, 3693 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 }; 3694 3695 /* Get a constraint for the requested part of a function designator FI 3696 when operating in IPA mode. */ 3697 3698 static struct constraint_expr 3699 get_function_part_constraint (varinfo_t fi, unsigned part) 3700 { 3701 struct constraint_expr c; 3702 3703 gcc_assert (in_ipa_mode); 3704 3705 if (fi->id == anything_id) 3706 { 3707 /* ??? We probably should have a ANYFN special variable. */ 3708 c.var = anything_id; 3709 c.offset = 0; 3710 c.type = SCALAR; 3711 } 3712 else if (TREE_CODE (fi->decl) == FUNCTION_DECL) 3713 { 3714 varinfo_t ai = first_vi_for_offset (fi, part); 3715 if (ai) 3716 c.var = ai->id; 3717 else 3718 c.var = anything_id; 3719 c.offset = 0; 3720 c.type = SCALAR; 3721 } 3722 else 3723 { 3724 c.var = fi->id; 3725 c.offset = part; 3726 c.type = DEREF; 3727 } 3728 3729 return c; 3730 } 3731 3732 /* For non-IPA mode, generate constraints necessary for a call on the 3733 RHS. */ 3734 3735 static void 3736 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results) 3737 { 3738 struct constraint_expr rhsc; 3739 unsigned i; 3740 bool returns_uses = false; 3741 3742 for (i = 0; i < gimple_call_num_args (stmt); ++i) 3743 { 3744 tree arg = gimple_call_arg (stmt, i); 3745 int flags = gimple_call_arg_flags (stmt, i); 3746 3747 /* If the argument is not used we can ignore it. */ 3748 if (flags & EAF_UNUSED) 3749 continue; 3750 3751 /* As we compute ESCAPED context-insensitive we do not gain 3752 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE 3753 set. The argument would still get clobbered through the 3754 escape solution. */ 3755 if ((flags & EAF_NOCLOBBER) 3756 && (flags & EAF_NOESCAPE)) 3757 { 3758 varinfo_t uses = get_call_use_vi (stmt); 3759 if (!(flags & EAF_DIRECT)) 3760 { 3761 varinfo_t tem = new_var_info (NULL_TREE, "callarg"); 3762 make_constraint_to (tem->id, arg); 3763 make_transitive_closure_constraints (tem); 3764 make_copy_constraint (uses, tem->id); 3765 } 3766 else 3767 make_constraint_to (uses->id, arg); 3768 returns_uses = true; 3769 } 3770 else if (flags & EAF_NOESCAPE) 3771 { 3772 struct constraint_expr lhs, rhs; 3773 varinfo_t uses = get_call_use_vi (stmt); 3774 varinfo_t clobbers = get_call_clobber_vi (stmt); 3775 varinfo_t tem = new_var_info (NULL_TREE, "callarg"); 3776 make_constraint_to (tem->id, arg); 3777 if (!(flags & EAF_DIRECT)) 3778 make_transitive_closure_constraints (tem); 3779 make_copy_constraint (uses, tem->id); 3780 make_copy_constraint (clobbers, tem->id); 3781 /* Add *tem = nonlocal, do not add *tem = callused as 3782 EAF_NOESCAPE parameters do not escape to other parameters 3783 and all other uses appear in NONLOCAL as well. */ 3784 lhs.type = DEREF; 3785 lhs.var = tem->id; 3786 lhs.offset = 0; 3787 rhs.type = SCALAR; 3788 rhs.var = nonlocal_id; 3789 rhs.offset = 0; 3790 process_constraint (new_constraint (lhs, rhs)); 3791 returns_uses = true; 3792 } 3793 else 3794 make_escape_constraint (arg); 3795 } 3796 3797 /* If we added to the calls uses solution make sure we account for 3798 pointers to it to be returned. */ 3799 if (returns_uses) 3800 { 3801 rhsc.var = get_call_use_vi (stmt)->id; 3802 rhsc.offset = 0; 3803 rhsc.type = SCALAR; 3804 VEC_safe_push (ce_s, heap, *results, &rhsc); 3805 } 3806 3807 /* The static chain escapes as well. */ 3808 if (gimple_call_chain (stmt)) 3809 make_escape_constraint (gimple_call_chain (stmt)); 3810 3811 /* And if we applied NRV the address of the return slot escapes as well. */ 3812 if (gimple_call_return_slot_opt_p (stmt) 3813 && gimple_call_lhs (stmt) != NULL_TREE 3814 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt)))) 3815 { 3816 VEC(ce_s, heap) *tmpc = NULL; 3817 struct constraint_expr lhsc, *c; 3818 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc); 3819 lhsc.var = escaped_id; 3820 lhsc.offset = 0; 3821 lhsc.type = SCALAR; 3822 FOR_EACH_VEC_ELT (ce_s, tmpc, i, c) 3823 process_constraint (new_constraint (lhsc, *c)); 3824 VEC_free(ce_s, heap, tmpc); 3825 } 3826 3827 /* Regular functions return nonlocal memory. */ 3828 rhsc.var = nonlocal_id; 3829 rhsc.offset = 0; 3830 rhsc.type = SCALAR; 3831 VEC_safe_push (ce_s, heap, *results, &rhsc); 3832 } 3833 3834 /* For non-IPA mode, generate constraints necessary for a call 3835 that returns a pointer and assigns it to LHS. This simply makes 3836 the LHS point to global and escaped variables. */ 3837 3838 static void 3839 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc, 3840 tree fndecl) 3841 { 3842 VEC(ce_s, heap) *lhsc = NULL; 3843 3844 get_constraint_for (lhs, &lhsc); 3845 /* If the store is to a global decl make sure to 3846 add proper escape constraints. */ 3847 lhs = get_base_address (lhs); 3848 if (lhs 3849 && DECL_P (lhs) 3850 && is_global_var (lhs)) 3851 { 3852 struct constraint_expr tmpc; 3853 tmpc.var = escaped_id; 3854 tmpc.offset = 0; 3855 tmpc.type = SCALAR; 3856 VEC_safe_push (ce_s, heap, lhsc, &tmpc); 3857 } 3858 3859 /* If the call returns an argument unmodified override the rhs 3860 constraints. */ 3861 flags = gimple_call_return_flags (stmt); 3862 if (flags & ERF_RETURNS_ARG 3863 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt)) 3864 { 3865 tree arg; 3866 rhsc = NULL; 3867 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK); 3868 get_constraint_for (arg, &rhsc); 3869 process_all_all_constraints (lhsc, rhsc); 3870 VEC_free (ce_s, heap, rhsc); 3871 } 3872 else if (flags & ERF_NOALIAS) 3873 { 3874 varinfo_t vi; 3875 struct constraint_expr tmpc; 3876 rhsc = NULL; 3877 vi = make_heapvar ("HEAP"); 3878 /* We delay marking allocated storage global until we know if 3879 it escapes. */ 3880 DECL_EXTERNAL (vi->decl) = 0; 3881 vi->is_global_var = 0; 3882 /* If this is not a real malloc call assume the memory was 3883 initialized and thus may point to global memory. All 3884 builtin functions with the malloc attribute behave in a sane way. */ 3885 if (!fndecl 3886 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL) 3887 make_constraint_from (vi, nonlocal_id); 3888 tmpc.var = vi->id; 3889 tmpc.offset = 0; 3890 tmpc.type = ADDRESSOF; 3891 VEC_safe_push (ce_s, heap, rhsc, &tmpc); 3892 process_all_all_constraints (lhsc, rhsc); 3893 VEC_free (ce_s, heap, rhsc); 3894 } 3895 else 3896 process_all_all_constraints (lhsc, rhsc); 3897 3898 VEC_free (ce_s, heap, lhsc); 3899 } 3900 3901 /* For non-IPA mode, generate constraints necessary for a call of a 3902 const function that returns a pointer in the statement STMT. */ 3903 3904 static void 3905 handle_const_call (gimple stmt, VEC(ce_s, heap) **results) 3906 { 3907 struct constraint_expr rhsc; 3908 unsigned int k; 3909 3910 /* Treat nested const functions the same as pure functions as far 3911 as the static chain is concerned. */ 3912 if (gimple_call_chain (stmt)) 3913 { 3914 varinfo_t uses = get_call_use_vi (stmt); 3915 make_transitive_closure_constraints (uses); 3916 make_constraint_to (uses->id, gimple_call_chain (stmt)); 3917 rhsc.var = uses->id; 3918 rhsc.offset = 0; 3919 rhsc.type = SCALAR; 3920 VEC_safe_push (ce_s, heap, *results, &rhsc); 3921 } 3922 3923 /* May return arguments. */ 3924 for (k = 0; k < gimple_call_num_args (stmt); ++k) 3925 { 3926 tree arg = gimple_call_arg (stmt, k); 3927 VEC(ce_s, heap) *argc = NULL; 3928 unsigned i; 3929 struct constraint_expr *argp; 3930 get_constraint_for_rhs (arg, &argc); 3931 FOR_EACH_VEC_ELT (ce_s, argc, i, argp) 3932 VEC_safe_push (ce_s, heap, *results, argp); 3933 VEC_free(ce_s, heap, argc); 3934 } 3935 3936 /* May return addresses of globals. */ 3937 rhsc.var = nonlocal_id; 3938 rhsc.offset = 0; 3939 rhsc.type = ADDRESSOF; 3940 VEC_safe_push (ce_s, heap, *results, &rhsc); 3941 } 3942 3943 /* For non-IPA mode, generate constraints necessary for a call to a 3944 pure function in statement STMT. */ 3945 3946 static void 3947 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results) 3948 { 3949 struct constraint_expr rhsc; 3950 unsigned i; 3951 varinfo_t uses = NULL; 3952 3953 /* Memory reached from pointer arguments is call-used. */ 3954 for (i = 0; i < gimple_call_num_args (stmt); ++i) 3955 { 3956 tree arg = gimple_call_arg (stmt, i); 3957 if (!uses) 3958 { 3959 uses = get_call_use_vi (stmt); 3960 make_transitive_closure_constraints (uses); 3961 } 3962 make_constraint_to (uses->id, arg); 3963 } 3964 3965 /* The static chain is used as well. */ 3966 if (gimple_call_chain (stmt)) 3967 { 3968 if (!uses) 3969 { 3970 uses = get_call_use_vi (stmt); 3971 make_transitive_closure_constraints (uses); 3972 } 3973 make_constraint_to (uses->id, gimple_call_chain (stmt)); 3974 } 3975 3976 /* Pure functions may return call-used and nonlocal memory. */ 3977 if (uses) 3978 { 3979 rhsc.var = uses->id; 3980 rhsc.offset = 0; 3981 rhsc.type = SCALAR; 3982 VEC_safe_push (ce_s, heap, *results, &rhsc); 3983 } 3984 rhsc.var = nonlocal_id; 3985 rhsc.offset = 0; 3986 rhsc.type = SCALAR; 3987 VEC_safe_push (ce_s, heap, *results, &rhsc); 3988 } 3989 3990 3991 /* Return the varinfo for the callee of CALL. */ 3992 3993 static varinfo_t 3994 get_fi_for_callee (gimple call) 3995 { 3996 tree decl, fn = gimple_call_fn (call); 3997 3998 if (fn && TREE_CODE (fn) == OBJ_TYPE_REF) 3999 fn = OBJ_TYPE_REF_EXPR (fn); 4000 4001 /* If we can directly resolve the function being called, do so. 4002 Otherwise, it must be some sort of indirect expression that 4003 we should still be able to handle. */ 4004 decl = gimple_call_addr_fndecl (fn); 4005 if (decl) 4006 return get_vi_for_tree (decl); 4007 4008 /* If the function is anything other than a SSA name pointer we have no 4009 clue and should be getting ANYFN (well, ANYTHING for now). */ 4010 if (!fn || TREE_CODE (fn) != SSA_NAME) 4011 return get_varinfo (anything_id); 4012 4013 if ((TREE_CODE (SSA_NAME_VAR (fn)) == PARM_DECL 4014 || TREE_CODE (SSA_NAME_VAR (fn)) == RESULT_DECL) 4015 && SSA_NAME_IS_DEFAULT_DEF (fn)) 4016 fn = SSA_NAME_VAR (fn); 4017 4018 return get_vi_for_tree (fn); 4019 } 4020 4021 /* Create constraints for the builtin call T. Return true if the call 4022 was handled, otherwise false. */ 4023 4024 static bool 4025 find_func_aliases_for_builtin_call (gimple t) 4026 { 4027 tree fndecl = gimple_call_fndecl (t); 4028 VEC(ce_s, heap) *lhsc = NULL; 4029 VEC(ce_s, heap) *rhsc = NULL; 4030 varinfo_t fi; 4031 4032 if (gimple_call_builtin_class_p (t, BUILT_IN_NORMAL)) 4033 /* ??? All builtins that are handled here need to be handled 4034 in the alias-oracle query functions explicitly! */ 4035 switch (DECL_FUNCTION_CODE (fndecl)) 4036 { 4037 /* All the following functions return a pointer to the same object 4038 as their first argument points to. The functions do not add 4039 to the ESCAPED solution. The functions make the first argument 4040 pointed to memory point to what the second argument pointed to 4041 memory points to. */ 4042 case BUILT_IN_STRCPY: 4043 case BUILT_IN_STRNCPY: 4044 case BUILT_IN_BCOPY: 4045 case BUILT_IN_MEMCPY: 4046 case BUILT_IN_MEMMOVE: 4047 case BUILT_IN_MEMPCPY: 4048 case BUILT_IN_STPCPY: 4049 case BUILT_IN_STPNCPY: 4050 case BUILT_IN_STRCAT: 4051 case BUILT_IN_STRNCAT: 4052 case BUILT_IN_STRCPY_CHK: 4053 case BUILT_IN_STRNCPY_CHK: 4054 case BUILT_IN_MEMCPY_CHK: 4055 case BUILT_IN_MEMMOVE_CHK: 4056 case BUILT_IN_MEMPCPY_CHK: 4057 case BUILT_IN_STPCPY_CHK: 4058 case BUILT_IN_STPNCPY_CHK: 4059 case BUILT_IN_STRCAT_CHK: 4060 case BUILT_IN_STRNCAT_CHK: 4061 case BUILT_IN_TM_MEMCPY: 4062 case BUILT_IN_TM_MEMMOVE: 4063 { 4064 tree res = gimple_call_lhs (t); 4065 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl) 4066 == BUILT_IN_BCOPY ? 1 : 0)); 4067 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl) 4068 == BUILT_IN_BCOPY ? 0 : 1)); 4069 if (res != NULL_TREE) 4070 { 4071 get_constraint_for (res, &lhsc); 4072 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY 4073 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY 4074 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY 4075 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY_CHK 4076 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY_CHK 4077 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY_CHK) 4078 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc); 4079 else 4080 get_constraint_for (dest, &rhsc); 4081 process_all_all_constraints (lhsc, rhsc); 4082 VEC_free (ce_s, heap, lhsc); 4083 VEC_free (ce_s, heap, rhsc); 4084 } 4085 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc); 4086 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc); 4087 do_deref (&lhsc); 4088 do_deref (&rhsc); 4089 process_all_all_constraints (lhsc, rhsc); 4090 VEC_free (ce_s, heap, lhsc); 4091 VEC_free (ce_s, heap, rhsc); 4092 return true; 4093 } 4094 case BUILT_IN_MEMSET: 4095 case BUILT_IN_MEMSET_CHK: 4096 case BUILT_IN_TM_MEMSET: 4097 { 4098 tree res = gimple_call_lhs (t); 4099 tree dest = gimple_call_arg (t, 0); 4100 unsigned i; 4101 ce_s *lhsp; 4102 struct constraint_expr ac; 4103 if (res != NULL_TREE) 4104 { 4105 get_constraint_for (res, &lhsc); 4106 get_constraint_for (dest, &rhsc); 4107 process_all_all_constraints (lhsc, rhsc); 4108 VEC_free (ce_s, heap, lhsc); 4109 VEC_free (ce_s, heap, rhsc); 4110 } 4111 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc); 4112 do_deref (&lhsc); 4113 if (flag_delete_null_pointer_checks 4114 && integer_zerop (gimple_call_arg (t, 1))) 4115 { 4116 ac.type = ADDRESSOF; 4117 ac.var = nothing_id; 4118 } 4119 else 4120 { 4121 ac.type = SCALAR; 4122 ac.var = integer_id; 4123 } 4124 ac.offset = 0; 4125 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp) 4126 process_constraint (new_constraint (*lhsp, ac)); 4127 VEC_free (ce_s, heap, lhsc); 4128 return true; 4129 } 4130 case BUILT_IN_ASSUME_ALIGNED: 4131 { 4132 tree res = gimple_call_lhs (t); 4133 tree dest = gimple_call_arg (t, 0); 4134 if (res != NULL_TREE) 4135 { 4136 get_constraint_for (res, &lhsc); 4137 get_constraint_for (dest, &rhsc); 4138 process_all_all_constraints (lhsc, rhsc); 4139 VEC_free (ce_s, heap, lhsc); 4140 VEC_free (ce_s, heap, rhsc); 4141 } 4142 return true; 4143 } 4144 /* All the following functions do not return pointers, do not 4145 modify the points-to sets of memory reachable from their 4146 arguments and do not add to the ESCAPED solution. */ 4147 case BUILT_IN_SINCOS: 4148 case BUILT_IN_SINCOSF: 4149 case BUILT_IN_SINCOSL: 4150 case BUILT_IN_FREXP: 4151 case BUILT_IN_FREXPF: 4152 case BUILT_IN_FREXPL: 4153 case BUILT_IN_GAMMA_R: 4154 case BUILT_IN_GAMMAF_R: 4155 case BUILT_IN_GAMMAL_R: 4156 case BUILT_IN_LGAMMA_R: 4157 case BUILT_IN_LGAMMAF_R: 4158 case BUILT_IN_LGAMMAL_R: 4159 case BUILT_IN_MODF: 4160 case BUILT_IN_MODFF: 4161 case BUILT_IN_MODFL: 4162 case BUILT_IN_REMQUO: 4163 case BUILT_IN_REMQUOF: 4164 case BUILT_IN_REMQUOL: 4165 case BUILT_IN_FREE: 4166 return true; 4167 case BUILT_IN_STRDUP: 4168 case BUILT_IN_STRNDUP: 4169 if (gimple_call_lhs (t)) 4170 { 4171 handle_lhs_call (t, gimple_call_lhs (t), gimple_call_flags (t), 4172 NULL, fndecl); 4173 get_constraint_for_ptr_offset (gimple_call_lhs (t), 4174 NULL_TREE, &lhsc); 4175 get_constraint_for_ptr_offset (gimple_call_arg (t, 0), 4176 NULL_TREE, &rhsc); 4177 do_deref (&lhsc); 4178 do_deref (&rhsc); 4179 process_all_all_constraints (lhsc, rhsc); 4180 VEC_free (ce_s, heap, lhsc); 4181 VEC_free (ce_s, heap, rhsc); 4182 return true; 4183 } 4184 break; 4185 /* Trampolines are special - they set up passing the static 4186 frame. */ 4187 case BUILT_IN_INIT_TRAMPOLINE: 4188 { 4189 tree tramp = gimple_call_arg (t, 0); 4190 tree nfunc = gimple_call_arg (t, 1); 4191 tree frame = gimple_call_arg (t, 2); 4192 unsigned i; 4193 struct constraint_expr lhs, *rhsp; 4194 if (in_ipa_mode) 4195 { 4196 varinfo_t nfi = NULL; 4197 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR); 4198 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0)); 4199 if (nfi) 4200 { 4201 lhs = get_function_part_constraint (nfi, fi_static_chain); 4202 get_constraint_for (frame, &rhsc); 4203 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp) 4204 process_constraint (new_constraint (lhs, *rhsp)); 4205 VEC_free (ce_s, heap, rhsc); 4206 4207 /* Make the frame point to the function for 4208 the trampoline adjustment call. */ 4209 get_constraint_for (tramp, &lhsc); 4210 do_deref (&lhsc); 4211 get_constraint_for (nfunc, &rhsc); 4212 process_all_all_constraints (lhsc, rhsc); 4213 VEC_free (ce_s, heap, rhsc); 4214 VEC_free (ce_s, heap, lhsc); 4215 4216 return true; 4217 } 4218 } 4219 /* Else fallthru to generic handling which will let 4220 the frame escape. */ 4221 break; 4222 } 4223 case BUILT_IN_ADJUST_TRAMPOLINE: 4224 { 4225 tree tramp = gimple_call_arg (t, 0); 4226 tree res = gimple_call_lhs (t); 4227 if (in_ipa_mode && res) 4228 { 4229 get_constraint_for (res, &lhsc); 4230 get_constraint_for (tramp, &rhsc); 4231 do_deref (&rhsc); 4232 process_all_all_constraints (lhsc, rhsc); 4233 VEC_free (ce_s, heap, rhsc); 4234 VEC_free (ce_s, heap, lhsc); 4235 } 4236 return true; 4237 } 4238 CASE_BUILT_IN_TM_STORE (1): 4239 CASE_BUILT_IN_TM_STORE (2): 4240 CASE_BUILT_IN_TM_STORE (4): 4241 CASE_BUILT_IN_TM_STORE (8): 4242 CASE_BUILT_IN_TM_STORE (FLOAT): 4243 CASE_BUILT_IN_TM_STORE (DOUBLE): 4244 CASE_BUILT_IN_TM_STORE (LDOUBLE): 4245 CASE_BUILT_IN_TM_STORE (M64): 4246 CASE_BUILT_IN_TM_STORE (M128): 4247 CASE_BUILT_IN_TM_STORE (M256): 4248 { 4249 tree addr = gimple_call_arg (t, 0); 4250 tree src = gimple_call_arg (t, 1); 4251 4252 get_constraint_for (addr, &lhsc); 4253 do_deref (&lhsc); 4254 get_constraint_for (src, &rhsc); 4255 process_all_all_constraints (lhsc, rhsc); 4256 VEC_free (ce_s, heap, lhsc); 4257 VEC_free (ce_s, heap, rhsc); 4258 return true; 4259 } 4260 CASE_BUILT_IN_TM_LOAD (1): 4261 CASE_BUILT_IN_TM_LOAD (2): 4262 CASE_BUILT_IN_TM_LOAD (4): 4263 CASE_BUILT_IN_TM_LOAD (8): 4264 CASE_BUILT_IN_TM_LOAD (FLOAT): 4265 CASE_BUILT_IN_TM_LOAD (DOUBLE): 4266 CASE_BUILT_IN_TM_LOAD (LDOUBLE): 4267 CASE_BUILT_IN_TM_LOAD (M64): 4268 CASE_BUILT_IN_TM_LOAD (M128): 4269 CASE_BUILT_IN_TM_LOAD (M256): 4270 { 4271 tree dest = gimple_call_lhs (t); 4272 tree addr = gimple_call_arg (t, 0); 4273 4274 get_constraint_for (dest, &lhsc); 4275 get_constraint_for (addr, &rhsc); 4276 do_deref (&rhsc); 4277 process_all_all_constraints (lhsc, rhsc); 4278 VEC_free (ce_s, heap, lhsc); 4279 VEC_free (ce_s, heap, rhsc); 4280 return true; 4281 } 4282 /* Variadic argument handling needs to be handled in IPA 4283 mode as well. */ 4284 case BUILT_IN_VA_START: 4285 { 4286 tree valist = gimple_call_arg (t, 0); 4287 struct constraint_expr rhs, *lhsp; 4288 unsigned i; 4289 get_constraint_for (valist, &lhsc); 4290 do_deref (&lhsc); 4291 /* The va_list gets access to pointers in variadic 4292 arguments. Which we know in the case of IPA analysis 4293 and otherwise are just all nonlocal variables. */ 4294 if (in_ipa_mode) 4295 { 4296 fi = lookup_vi_for_tree (cfun->decl); 4297 rhs = get_function_part_constraint (fi, ~0); 4298 rhs.type = ADDRESSOF; 4299 } 4300 else 4301 { 4302 rhs.var = nonlocal_id; 4303 rhs.type = ADDRESSOF; 4304 rhs.offset = 0; 4305 } 4306 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp) 4307 process_constraint (new_constraint (*lhsp, rhs)); 4308 VEC_free (ce_s, heap, lhsc); 4309 /* va_list is clobbered. */ 4310 make_constraint_to (get_call_clobber_vi (t)->id, valist); 4311 return true; 4312 } 4313 /* va_end doesn't have any effect that matters. */ 4314 case BUILT_IN_VA_END: 4315 return true; 4316 /* Alternate return. Simply give up for now. */ 4317 case BUILT_IN_RETURN: 4318 { 4319 fi = NULL; 4320 if (!in_ipa_mode 4321 || !(fi = get_vi_for_tree (cfun->decl))) 4322 make_constraint_from (get_varinfo (escaped_id), anything_id); 4323 else if (in_ipa_mode 4324 && fi != NULL) 4325 { 4326 struct constraint_expr lhs, rhs; 4327 lhs = get_function_part_constraint (fi, fi_result); 4328 rhs.var = anything_id; 4329 rhs.offset = 0; 4330 rhs.type = SCALAR; 4331 process_constraint (new_constraint (lhs, rhs)); 4332 } 4333 return true; 4334 } 4335 /* printf-style functions may have hooks to set pointers to 4336 point to somewhere into the generated string. Leave them 4337 for a later excercise... */ 4338 default: 4339 /* Fallthru to general call handling. */; 4340 } 4341 4342 return false; 4343 } 4344 4345 /* Create constraints for the call T. */ 4346 4347 static void 4348 find_func_aliases_for_call (gimple t) 4349 { 4350 tree fndecl = gimple_call_fndecl (t); 4351 VEC(ce_s, heap) *lhsc = NULL; 4352 VEC(ce_s, heap) *rhsc = NULL; 4353 varinfo_t fi; 4354 4355 if (fndecl != NULL_TREE 4356 && DECL_BUILT_IN (fndecl) 4357 && find_func_aliases_for_builtin_call (t)) 4358 return; 4359 4360 fi = get_fi_for_callee (t); 4361 if (!in_ipa_mode 4362 || (fndecl && !fi->is_fn_info)) 4363 { 4364 VEC(ce_s, heap) *rhsc = NULL; 4365 int flags = gimple_call_flags (t); 4366 4367 /* Const functions can return their arguments and addresses 4368 of global memory but not of escaped memory. */ 4369 if (flags & (ECF_CONST|ECF_NOVOPS)) 4370 { 4371 if (gimple_call_lhs (t)) 4372 handle_const_call (t, &rhsc); 4373 } 4374 /* Pure functions can return addresses in and of memory 4375 reachable from their arguments, but they are not an escape 4376 point for reachable memory of their arguments. */ 4377 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE)) 4378 handle_pure_call (t, &rhsc); 4379 else 4380 handle_rhs_call (t, &rhsc); 4381 if (gimple_call_lhs (t)) 4382 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl); 4383 VEC_free (ce_s, heap, rhsc); 4384 } 4385 else 4386 { 4387 tree lhsop; 4388 unsigned j; 4389 4390 /* Assign all the passed arguments to the appropriate incoming 4391 parameters of the function. */ 4392 for (j = 0; j < gimple_call_num_args (t); j++) 4393 { 4394 struct constraint_expr lhs ; 4395 struct constraint_expr *rhsp; 4396 tree arg = gimple_call_arg (t, j); 4397 4398 get_constraint_for_rhs (arg, &rhsc); 4399 lhs = get_function_part_constraint (fi, fi_parm_base + j); 4400 while (VEC_length (ce_s, rhsc) != 0) 4401 { 4402 rhsp = VEC_last (ce_s, rhsc); 4403 process_constraint (new_constraint (lhs, *rhsp)); 4404 VEC_pop (ce_s, rhsc); 4405 } 4406 } 4407 4408 /* If we are returning a value, assign it to the result. */ 4409 lhsop = gimple_call_lhs (t); 4410 if (lhsop) 4411 { 4412 struct constraint_expr rhs; 4413 struct constraint_expr *lhsp; 4414 4415 get_constraint_for (lhsop, &lhsc); 4416 rhs = get_function_part_constraint (fi, fi_result); 4417 if (fndecl 4418 && DECL_RESULT (fndecl) 4419 && DECL_BY_REFERENCE (DECL_RESULT (fndecl))) 4420 { 4421 VEC(ce_s, heap) *tem = NULL; 4422 VEC_safe_push (ce_s, heap, tem, &rhs); 4423 do_deref (&tem); 4424 rhs = *VEC_index (ce_s, tem, 0); 4425 VEC_free(ce_s, heap, tem); 4426 } 4427 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp) 4428 process_constraint (new_constraint (*lhsp, rhs)); 4429 } 4430 4431 /* If we pass the result decl by reference, honor that. */ 4432 if (lhsop 4433 && fndecl 4434 && DECL_RESULT (fndecl) 4435 && DECL_BY_REFERENCE (DECL_RESULT (fndecl))) 4436 { 4437 struct constraint_expr lhs; 4438 struct constraint_expr *rhsp; 4439 4440 get_constraint_for_address_of (lhsop, &rhsc); 4441 lhs = get_function_part_constraint (fi, fi_result); 4442 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp) 4443 process_constraint (new_constraint (lhs, *rhsp)); 4444 VEC_free (ce_s, heap, rhsc); 4445 } 4446 4447 /* If we use a static chain, pass it along. */ 4448 if (gimple_call_chain (t)) 4449 { 4450 struct constraint_expr lhs; 4451 struct constraint_expr *rhsp; 4452 4453 get_constraint_for (gimple_call_chain (t), &rhsc); 4454 lhs = get_function_part_constraint (fi, fi_static_chain); 4455 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp) 4456 process_constraint (new_constraint (lhs, *rhsp)); 4457 } 4458 } 4459 } 4460 4461 /* Walk statement T setting up aliasing constraints according to the 4462 references found in T. This function is the main part of the 4463 constraint builder. AI points to auxiliary alias information used 4464 when building alias sets and computing alias grouping heuristics. */ 4465 4466 static void 4467 find_func_aliases (gimple origt) 4468 { 4469 gimple t = origt; 4470 VEC(ce_s, heap) *lhsc = NULL; 4471 VEC(ce_s, heap) *rhsc = NULL; 4472 struct constraint_expr *c; 4473 varinfo_t fi; 4474 4475 /* Now build constraints expressions. */ 4476 if (gimple_code (t) == GIMPLE_PHI) 4477 { 4478 size_t i; 4479 unsigned int j; 4480 4481 /* For a phi node, assign all the arguments to 4482 the result. */ 4483 get_constraint_for (gimple_phi_result (t), &lhsc); 4484 for (i = 0; i < gimple_phi_num_args (t); i++) 4485 { 4486 tree strippedrhs = PHI_ARG_DEF (t, i); 4487 4488 STRIP_NOPS (strippedrhs); 4489 get_constraint_for_rhs (gimple_phi_arg_def (t, i), &rhsc); 4490 4491 FOR_EACH_VEC_ELT (ce_s, lhsc, j, c) 4492 { 4493 struct constraint_expr *c2; 4494 while (VEC_length (ce_s, rhsc) > 0) 4495 { 4496 c2 = VEC_last (ce_s, rhsc); 4497 process_constraint (new_constraint (*c, *c2)); 4498 VEC_pop (ce_s, rhsc); 4499 } 4500 } 4501 } 4502 } 4503 /* In IPA mode, we need to generate constraints to pass call 4504 arguments through their calls. There are two cases, 4505 either a GIMPLE_CALL returning a value, or just a plain 4506 GIMPLE_CALL when we are not. 4507 4508 In non-ipa mode, we need to generate constraints for each 4509 pointer passed by address. */ 4510 else if (is_gimple_call (t)) 4511 find_func_aliases_for_call (t); 4512 4513 /* Otherwise, just a regular assignment statement. Only care about 4514 operations with pointer result, others are dealt with as escape 4515 points if they have pointer operands. */ 4516 else if (is_gimple_assign (t)) 4517 { 4518 /* Otherwise, just a regular assignment statement. */ 4519 tree lhsop = gimple_assign_lhs (t); 4520 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL; 4521 4522 if (rhsop && TREE_CLOBBER_P (rhsop)) 4523 /* Ignore clobbers, they don't actually store anything into 4524 the LHS. */ 4525 ; 4526 else if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop))) 4527 do_structure_copy (lhsop, rhsop); 4528 else 4529 { 4530 enum tree_code code = gimple_assign_rhs_code (t); 4531 4532 get_constraint_for (lhsop, &lhsc); 4533 4534 if (code == POINTER_PLUS_EXPR) 4535 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t), 4536 gimple_assign_rhs2 (t), &rhsc); 4537 else if (code == BIT_AND_EXPR 4538 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST) 4539 { 4540 /* Aligning a pointer via a BIT_AND_EXPR is offsetting 4541 the pointer. Handle it by offsetting it by UNKNOWN. */ 4542 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t), 4543 NULL_TREE, &rhsc); 4544 } 4545 else if ((CONVERT_EXPR_CODE_P (code) 4546 && !(POINTER_TYPE_P (gimple_expr_type (t)) 4547 && !POINTER_TYPE_P (TREE_TYPE (rhsop)))) 4548 || gimple_assign_single_p (t)) 4549 get_constraint_for_rhs (rhsop, &rhsc); 4550 else if (truth_value_p (code)) 4551 /* Truth value results are not pointer (parts). Or at least 4552 very very unreasonable obfuscation of a part. */ 4553 ; 4554 else 4555 { 4556 /* All other operations are merges. */ 4557 VEC (ce_s, heap) *tmp = NULL; 4558 struct constraint_expr *rhsp; 4559 unsigned i, j; 4560 get_constraint_for_rhs (gimple_assign_rhs1 (t), &rhsc); 4561 for (i = 2; i < gimple_num_ops (t); ++i) 4562 { 4563 get_constraint_for_rhs (gimple_op (t, i), &tmp); 4564 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp) 4565 VEC_safe_push (ce_s, heap, rhsc, rhsp); 4566 VEC_truncate (ce_s, tmp, 0); 4567 } 4568 VEC_free (ce_s, heap, tmp); 4569 } 4570 process_all_all_constraints (lhsc, rhsc); 4571 } 4572 /* If there is a store to a global variable the rhs escapes. */ 4573 if ((lhsop = get_base_address (lhsop)) != NULL_TREE 4574 && DECL_P (lhsop) 4575 && is_global_var (lhsop) 4576 && (!in_ipa_mode 4577 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop))) 4578 make_escape_constraint (rhsop); 4579 } 4580 /* Handle escapes through return. */ 4581 else if (gimple_code (t) == GIMPLE_RETURN 4582 && gimple_return_retval (t) != NULL_TREE) 4583 { 4584 fi = NULL; 4585 if (!in_ipa_mode 4586 || !(fi = get_vi_for_tree (cfun->decl))) 4587 make_escape_constraint (gimple_return_retval (t)); 4588 else if (in_ipa_mode 4589 && fi != NULL) 4590 { 4591 struct constraint_expr lhs ; 4592 struct constraint_expr *rhsp; 4593 unsigned i; 4594 4595 lhs = get_function_part_constraint (fi, fi_result); 4596 get_constraint_for_rhs (gimple_return_retval (t), &rhsc); 4597 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp) 4598 process_constraint (new_constraint (lhs, *rhsp)); 4599 } 4600 } 4601 /* Handle asms conservatively by adding escape constraints to everything. */ 4602 else if (gimple_code (t) == GIMPLE_ASM) 4603 { 4604 unsigned i, noutputs; 4605 const char **oconstraints; 4606 const char *constraint; 4607 bool allows_mem, allows_reg, is_inout; 4608 4609 noutputs = gimple_asm_noutputs (t); 4610 oconstraints = XALLOCAVEC (const char *, noutputs); 4611 4612 for (i = 0; i < noutputs; ++i) 4613 { 4614 tree link = gimple_asm_output_op (t, i); 4615 tree op = TREE_VALUE (link); 4616 4617 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link))); 4618 oconstraints[i] = constraint; 4619 parse_output_constraint (&constraint, i, 0, 0, &allows_mem, 4620 &allows_reg, &is_inout); 4621 4622 /* A memory constraint makes the address of the operand escape. */ 4623 if (!allows_reg && allows_mem) 4624 make_escape_constraint (build_fold_addr_expr (op)); 4625 4626 /* The asm may read global memory, so outputs may point to 4627 any global memory. */ 4628 if (op) 4629 { 4630 VEC(ce_s, heap) *lhsc = NULL; 4631 struct constraint_expr rhsc, *lhsp; 4632 unsigned j; 4633 get_constraint_for (op, &lhsc); 4634 rhsc.var = nonlocal_id; 4635 rhsc.offset = 0; 4636 rhsc.type = SCALAR; 4637 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp) 4638 process_constraint (new_constraint (*lhsp, rhsc)); 4639 VEC_free (ce_s, heap, lhsc); 4640 } 4641 } 4642 for (i = 0; i < gimple_asm_ninputs (t); ++i) 4643 { 4644 tree link = gimple_asm_input_op (t, i); 4645 tree op = TREE_VALUE (link); 4646 4647 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link))); 4648 4649 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints, 4650 &allows_mem, &allows_reg); 4651 4652 /* A memory constraint makes the address of the operand escape. */ 4653 if (!allows_reg && allows_mem) 4654 make_escape_constraint (build_fold_addr_expr (op)); 4655 /* Strictly we'd only need the constraint to ESCAPED if 4656 the asm clobbers memory, otherwise using something 4657 along the lines of per-call clobbers/uses would be enough. */ 4658 else if (op) 4659 make_escape_constraint (op); 4660 } 4661 } 4662 4663 VEC_free (ce_s, heap, rhsc); 4664 VEC_free (ce_s, heap, lhsc); 4665 } 4666 4667 4668 /* Create a constraint adding to the clobber set of FI the memory 4669 pointed to by PTR. */ 4670 4671 static void 4672 process_ipa_clobber (varinfo_t fi, tree ptr) 4673 { 4674 VEC(ce_s, heap) *ptrc = NULL; 4675 struct constraint_expr *c, lhs; 4676 unsigned i; 4677 get_constraint_for_rhs (ptr, &ptrc); 4678 lhs = get_function_part_constraint (fi, fi_clobbers); 4679 FOR_EACH_VEC_ELT (ce_s, ptrc, i, c) 4680 process_constraint (new_constraint (lhs, *c)); 4681 VEC_free (ce_s, heap, ptrc); 4682 } 4683 4684 /* Walk statement T setting up clobber and use constraints according to the 4685 references found in T. This function is a main part of the 4686 IPA constraint builder. */ 4687 4688 static void 4689 find_func_clobbers (gimple origt) 4690 { 4691 gimple t = origt; 4692 VEC(ce_s, heap) *lhsc = NULL; 4693 VEC(ce_s, heap) *rhsc = NULL; 4694 varinfo_t fi; 4695 4696 /* Add constraints for clobbered/used in IPA mode. 4697 We are not interested in what automatic variables are clobbered 4698 or used as we only use the information in the caller to which 4699 they do not escape. */ 4700 gcc_assert (in_ipa_mode); 4701 4702 /* If the stmt refers to memory in any way it better had a VUSE. */ 4703 if (gimple_vuse (t) == NULL_TREE) 4704 return; 4705 4706 /* We'd better have function information for the current function. */ 4707 fi = lookup_vi_for_tree (cfun->decl); 4708 gcc_assert (fi != NULL); 4709 4710 /* Account for stores in assignments and calls. */ 4711 if (gimple_vdef (t) != NULL_TREE 4712 && gimple_has_lhs (t)) 4713 { 4714 tree lhs = gimple_get_lhs (t); 4715 tree tem = lhs; 4716 while (handled_component_p (tem)) 4717 tem = TREE_OPERAND (tem, 0); 4718 if ((DECL_P (tem) 4719 && !auto_var_in_fn_p (tem, cfun->decl)) 4720 || INDIRECT_REF_P (tem) 4721 || (TREE_CODE (tem) == MEM_REF 4722 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR 4723 && auto_var_in_fn_p 4724 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl)))) 4725 { 4726 struct constraint_expr lhsc, *rhsp; 4727 unsigned i; 4728 lhsc = get_function_part_constraint (fi, fi_clobbers); 4729 get_constraint_for_address_of (lhs, &rhsc); 4730 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp) 4731 process_constraint (new_constraint (lhsc, *rhsp)); 4732 VEC_free (ce_s, heap, rhsc); 4733 } 4734 } 4735 4736 /* Account for uses in assigments and returns. */ 4737 if (gimple_assign_single_p (t) 4738 || (gimple_code (t) == GIMPLE_RETURN 4739 && gimple_return_retval (t) != NULL_TREE)) 4740 { 4741 tree rhs = (gimple_assign_single_p (t) 4742 ? gimple_assign_rhs1 (t) : gimple_return_retval (t)); 4743 tree tem = rhs; 4744 while (handled_component_p (tem)) 4745 tem = TREE_OPERAND (tem, 0); 4746 if ((DECL_P (tem) 4747 && !auto_var_in_fn_p (tem, cfun->decl)) 4748 || INDIRECT_REF_P (tem) 4749 || (TREE_CODE (tem) == MEM_REF 4750 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR 4751 && auto_var_in_fn_p 4752 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl)))) 4753 { 4754 struct constraint_expr lhs, *rhsp; 4755 unsigned i; 4756 lhs = get_function_part_constraint (fi, fi_uses); 4757 get_constraint_for_address_of (rhs, &rhsc); 4758 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp) 4759 process_constraint (new_constraint (lhs, *rhsp)); 4760 VEC_free (ce_s, heap, rhsc); 4761 } 4762 } 4763 4764 if (is_gimple_call (t)) 4765 { 4766 varinfo_t cfi = NULL; 4767 tree decl = gimple_call_fndecl (t); 4768 struct constraint_expr lhs, rhs; 4769 unsigned i, j; 4770 4771 /* For builtins we do not have separate function info. For those 4772 we do not generate escapes for we have to generate clobbers/uses. */ 4773 if (gimple_call_builtin_class_p (t, BUILT_IN_NORMAL)) 4774 switch (DECL_FUNCTION_CODE (decl)) 4775 { 4776 /* The following functions use and clobber memory pointed to 4777 by their arguments. */ 4778 case BUILT_IN_STRCPY: 4779 case BUILT_IN_STRNCPY: 4780 case BUILT_IN_BCOPY: 4781 case BUILT_IN_MEMCPY: 4782 case BUILT_IN_MEMMOVE: 4783 case BUILT_IN_MEMPCPY: 4784 case BUILT_IN_STPCPY: 4785 case BUILT_IN_STPNCPY: 4786 case BUILT_IN_STRCAT: 4787 case BUILT_IN_STRNCAT: 4788 case BUILT_IN_STRCPY_CHK: 4789 case BUILT_IN_STRNCPY_CHK: 4790 case BUILT_IN_MEMCPY_CHK: 4791 case BUILT_IN_MEMMOVE_CHK: 4792 case BUILT_IN_MEMPCPY_CHK: 4793 case BUILT_IN_STPCPY_CHK: 4794 case BUILT_IN_STPNCPY_CHK: 4795 case BUILT_IN_STRCAT_CHK: 4796 case BUILT_IN_STRNCAT_CHK: 4797 { 4798 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl) 4799 == BUILT_IN_BCOPY ? 1 : 0)); 4800 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl) 4801 == BUILT_IN_BCOPY ? 0 : 1)); 4802 unsigned i; 4803 struct constraint_expr *rhsp, *lhsp; 4804 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc); 4805 lhs = get_function_part_constraint (fi, fi_clobbers); 4806 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp) 4807 process_constraint (new_constraint (lhs, *lhsp)); 4808 VEC_free (ce_s, heap, lhsc); 4809 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc); 4810 lhs = get_function_part_constraint (fi, fi_uses); 4811 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp) 4812 process_constraint (new_constraint (lhs, *rhsp)); 4813 VEC_free (ce_s, heap, rhsc); 4814 return; 4815 } 4816 /* The following function clobbers memory pointed to by 4817 its argument. */ 4818 case BUILT_IN_MEMSET: 4819 case BUILT_IN_MEMSET_CHK: 4820 { 4821 tree dest = gimple_call_arg (t, 0); 4822 unsigned i; 4823 ce_s *lhsp; 4824 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc); 4825 lhs = get_function_part_constraint (fi, fi_clobbers); 4826 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp) 4827 process_constraint (new_constraint (lhs, *lhsp)); 4828 VEC_free (ce_s, heap, lhsc); 4829 return; 4830 } 4831 /* The following functions clobber their second and third 4832 arguments. */ 4833 case BUILT_IN_SINCOS: 4834 case BUILT_IN_SINCOSF: 4835 case BUILT_IN_SINCOSL: 4836 { 4837 process_ipa_clobber (fi, gimple_call_arg (t, 1)); 4838 process_ipa_clobber (fi, gimple_call_arg (t, 2)); 4839 return; 4840 } 4841 /* The following functions clobber their second argument. */ 4842 case BUILT_IN_FREXP: 4843 case BUILT_IN_FREXPF: 4844 case BUILT_IN_FREXPL: 4845 case BUILT_IN_LGAMMA_R: 4846 case BUILT_IN_LGAMMAF_R: 4847 case BUILT_IN_LGAMMAL_R: 4848 case BUILT_IN_GAMMA_R: 4849 case BUILT_IN_GAMMAF_R: 4850 case BUILT_IN_GAMMAL_R: 4851 case BUILT_IN_MODF: 4852 case BUILT_IN_MODFF: 4853 case BUILT_IN_MODFL: 4854 { 4855 process_ipa_clobber (fi, gimple_call_arg (t, 1)); 4856 return; 4857 } 4858 /* The following functions clobber their third argument. */ 4859 case BUILT_IN_REMQUO: 4860 case BUILT_IN_REMQUOF: 4861 case BUILT_IN_REMQUOL: 4862 { 4863 process_ipa_clobber (fi, gimple_call_arg (t, 2)); 4864 return; 4865 } 4866 /* The following functions neither read nor clobber memory. */ 4867 case BUILT_IN_ASSUME_ALIGNED: 4868 case BUILT_IN_FREE: 4869 return; 4870 /* Trampolines are of no interest to us. */ 4871 case BUILT_IN_INIT_TRAMPOLINE: 4872 case BUILT_IN_ADJUST_TRAMPOLINE: 4873 return; 4874 case BUILT_IN_VA_START: 4875 case BUILT_IN_VA_END: 4876 return; 4877 /* printf-style functions may have hooks to set pointers to 4878 point to somewhere into the generated string. Leave them 4879 for a later excercise... */ 4880 default: 4881 /* Fallthru to general call handling. */; 4882 } 4883 4884 /* Parameters passed by value are used. */ 4885 lhs = get_function_part_constraint (fi, fi_uses); 4886 for (i = 0; i < gimple_call_num_args (t); i++) 4887 { 4888 struct constraint_expr *rhsp; 4889 tree arg = gimple_call_arg (t, i); 4890 4891 if (TREE_CODE (arg) == SSA_NAME 4892 || is_gimple_min_invariant (arg)) 4893 continue; 4894 4895 get_constraint_for_address_of (arg, &rhsc); 4896 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp) 4897 process_constraint (new_constraint (lhs, *rhsp)); 4898 VEC_free (ce_s, heap, rhsc); 4899 } 4900 4901 /* Build constraints for propagating clobbers/uses along the 4902 callgraph edges. */ 4903 cfi = get_fi_for_callee (t); 4904 if (cfi->id == anything_id) 4905 { 4906 if (gimple_vdef (t)) 4907 make_constraint_from (first_vi_for_offset (fi, fi_clobbers), 4908 anything_id); 4909 make_constraint_from (first_vi_for_offset (fi, fi_uses), 4910 anything_id); 4911 return; 4912 } 4913 4914 /* For callees without function info (that's external functions), 4915 ESCAPED is clobbered and used. */ 4916 if (gimple_call_fndecl (t) 4917 && !cfi->is_fn_info) 4918 { 4919 varinfo_t vi; 4920 4921 if (gimple_vdef (t)) 4922 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers), 4923 escaped_id); 4924 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id); 4925 4926 /* Also honor the call statement use/clobber info. */ 4927 if ((vi = lookup_call_clobber_vi (t)) != NULL) 4928 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers), 4929 vi->id); 4930 if ((vi = lookup_call_use_vi (t)) != NULL) 4931 make_copy_constraint (first_vi_for_offset (fi, fi_uses), 4932 vi->id); 4933 return; 4934 } 4935 4936 /* Otherwise the caller clobbers and uses what the callee does. 4937 ??? This should use a new complex constraint that filters 4938 local variables of the callee. */ 4939 if (gimple_vdef (t)) 4940 { 4941 lhs = get_function_part_constraint (fi, fi_clobbers); 4942 rhs = get_function_part_constraint (cfi, fi_clobbers); 4943 process_constraint (new_constraint (lhs, rhs)); 4944 } 4945 lhs = get_function_part_constraint (fi, fi_uses); 4946 rhs = get_function_part_constraint (cfi, fi_uses); 4947 process_constraint (new_constraint (lhs, rhs)); 4948 } 4949 else if (gimple_code (t) == GIMPLE_ASM) 4950 { 4951 /* ??? Ick. We can do better. */ 4952 if (gimple_vdef (t)) 4953 make_constraint_from (first_vi_for_offset (fi, fi_clobbers), 4954 anything_id); 4955 make_constraint_from (first_vi_for_offset (fi, fi_uses), 4956 anything_id); 4957 } 4958 4959 VEC_free (ce_s, heap, rhsc); 4960 } 4961 4962 4963 /* Find the first varinfo in the same variable as START that overlaps with 4964 OFFSET. Return NULL if we can't find one. */ 4965 4966 static varinfo_t 4967 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset) 4968 { 4969 /* If the offset is outside of the variable, bail out. */ 4970 if (offset >= start->fullsize) 4971 return NULL; 4972 4973 /* If we cannot reach offset from start, lookup the first field 4974 and start from there. */ 4975 if (start->offset > offset) 4976 start = lookup_vi_for_tree (start->decl); 4977 4978 while (start) 4979 { 4980 /* We may not find a variable in the field list with the actual 4981 offset when when we have glommed a structure to a variable. 4982 In that case, however, offset should still be within the size 4983 of the variable. */ 4984 if (offset >= start->offset 4985 && (offset - start->offset) < start->size) 4986 return start; 4987 4988 start= start->next; 4989 } 4990 4991 return NULL; 4992 } 4993 4994 /* Find the first varinfo in the same variable as START that overlaps with 4995 OFFSET. If there is no such varinfo the varinfo directly preceding 4996 OFFSET is returned. */ 4997 4998 static varinfo_t 4999 first_or_preceding_vi_for_offset (varinfo_t start, 5000 unsigned HOST_WIDE_INT offset) 5001 { 5002 /* If we cannot reach offset from start, lookup the first field 5003 and start from there. */ 5004 if (start->offset > offset) 5005 start = lookup_vi_for_tree (start->decl); 5006 5007 /* We may not find a variable in the field list with the actual 5008 offset when when we have glommed a structure to a variable. 5009 In that case, however, offset should still be within the size 5010 of the variable. 5011 If we got beyond the offset we look for return the field 5012 directly preceding offset which may be the last field. */ 5013 while (start->next 5014 && offset >= start->offset 5015 && !((offset - start->offset) < start->size)) 5016 start = start->next; 5017 5018 return start; 5019 } 5020 5021 5022 /* This structure is used during pushing fields onto the fieldstack 5023 to track the offset of the field, since bitpos_of_field gives it 5024 relative to its immediate containing type, and we want it relative 5025 to the ultimate containing object. */ 5026 5027 struct fieldoff 5028 { 5029 /* Offset from the base of the base containing object to this field. */ 5030 HOST_WIDE_INT offset; 5031 5032 /* Size, in bits, of the field. */ 5033 unsigned HOST_WIDE_INT size; 5034 5035 unsigned has_unknown_size : 1; 5036 5037 unsigned must_have_pointers : 1; 5038 5039 unsigned may_have_pointers : 1; 5040 5041 unsigned only_restrict_pointers : 1; 5042 }; 5043 typedef struct fieldoff fieldoff_s; 5044 5045 DEF_VEC_O(fieldoff_s); 5046 DEF_VEC_ALLOC_O(fieldoff_s,heap); 5047 5048 /* qsort comparison function for two fieldoff's PA and PB */ 5049 5050 static int 5051 fieldoff_compare (const void *pa, const void *pb) 5052 { 5053 const fieldoff_s *foa = (const fieldoff_s *)pa; 5054 const fieldoff_s *fob = (const fieldoff_s *)pb; 5055 unsigned HOST_WIDE_INT foasize, fobsize; 5056 5057 if (foa->offset < fob->offset) 5058 return -1; 5059 else if (foa->offset > fob->offset) 5060 return 1; 5061 5062 foasize = foa->size; 5063 fobsize = fob->size; 5064 if (foasize < fobsize) 5065 return -1; 5066 else if (foasize > fobsize) 5067 return 1; 5068 return 0; 5069 } 5070 5071 /* Sort a fieldstack according to the field offset and sizes. */ 5072 static void 5073 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack) 5074 { 5075 VEC_qsort (fieldoff_s, fieldstack, fieldoff_compare); 5076 } 5077 5078 /* Return true if T is a type that can have subvars. */ 5079 5080 static inline bool 5081 type_can_have_subvars (const_tree t) 5082 { 5083 /* Aggregates without overlapping fields can have subvars. */ 5084 return TREE_CODE (t) == RECORD_TYPE; 5085 } 5086 5087 /* Return true if V is a tree that we can have subvars for. 5088 Normally, this is any aggregate type. Also complex 5089 types which are not gimple registers can have subvars. */ 5090 5091 static inline bool 5092 var_can_have_subvars (const_tree v) 5093 { 5094 /* Volatile variables should never have subvars. */ 5095 if (TREE_THIS_VOLATILE (v)) 5096 return false; 5097 5098 /* Non decls or memory tags can never have subvars. */ 5099 if (!DECL_P (v)) 5100 return false; 5101 5102 return type_can_have_subvars (TREE_TYPE (v)); 5103 } 5104 5105 /* Return true if T is a type that does contain pointers. */ 5106 5107 static bool 5108 type_must_have_pointers (tree type) 5109 { 5110 if (POINTER_TYPE_P (type)) 5111 return true; 5112 5113 if (TREE_CODE (type) == ARRAY_TYPE) 5114 return type_must_have_pointers (TREE_TYPE (type)); 5115 5116 /* A function or method can have pointers as arguments, so track 5117 those separately. */ 5118 if (TREE_CODE (type) == FUNCTION_TYPE 5119 || TREE_CODE (type) == METHOD_TYPE) 5120 return true; 5121 5122 return false; 5123 } 5124 5125 static bool 5126 field_must_have_pointers (tree t) 5127 { 5128 return type_must_have_pointers (TREE_TYPE (t)); 5129 } 5130 5131 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all 5132 the fields of TYPE onto fieldstack, recording their offsets along 5133 the way. 5134 5135 OFFSET is used to keep track of the offset in this entire 5136 structure, rather than just the immediately containing structure. 5137 Returns false if the caller is supposed to handle the field we 5138 recursed for. */ 5139 5140 static bool 5141 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack, 5142 HOST_WIDE_INT offset) 5143 { 5144 tree field; 5145 bool empty_p = true; 5146 5147 if (TREE_CODE (type) != RECORD_TYPE) 5148 return false; 5149 5150 /* If the vector of fields is growing too big, bail out early. 5151 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make 5152 sure this fails. */ 5153 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE) 5154 return false; 5155 5156 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field)) 5157 if (TREE_CODE (field) == FIELD_DECL) 5158 { 5159 bool push = false; 5160 HOST_WIDE_INT foff = bitpos_of_field (field); 5161 5162 if (!var_can_have_subvars (field) 5163 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE 5164 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE) 5165 push = true; 5166 else if (!push_fields_onto_fieldstack 5167 (TREE_TYPE (field), fieldstack, offset + foff) 5168 && (DECL_SIZE (field) 5169 && !integer_zerop (DECL_SIZE (field)))) 5170 /* Empty structures may have actual size, like in C++. So 5171 see if we didn't push any subfields and the size is 5172 nonzero, push the field onto the stack. */ 5173 push = true; 5174 5175 if (push) 5176 { 5177 fieldoff_s *pair = NULL; 5178 bool has_unknown_size = false; 5179 bool must_have_pointers_p; 5180 5181 if (!VEC_empty (fieldoff_s, *fieldstack)) 5182 pair = VEC_last (fieldoff_s, *fieldstack); 5183 5184 /* If there isn't anything at offset zero, create sth. */ 5185 if (!pair 5186 && offset + foff != 0) 5187 { 5188 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL); 5189 pair->offset = 0; 5190 pair->size = offset + foff; 5191 pair->has_unknown_size = false; 5192 pair->must_have_pointers = false; 5193 pair->may_have_pointers = false; 5194 pair->only_restrict_pointers = false; 5195 } 5196 5197 if (!DECL_SIZE (field) 5198 || !host_integerp (DECL_SIZE (field), 1)) 5199 has_unknown_size = true; 5200 5201 /* If adjacent fields do not contain pointers merge them. */ 5202 must_have_pointers_p = field_must_have_pointers (field); 5203 if (pair 5204 && !has_unknown_size 5205 && !must_have_pointers_p 5206 && !pair->must_have_pointers 5207 && !pair->has_unknown_size 5208 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff) 5209 { 5210 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field)); 5211 } 5212 else 5213 { 5214 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL); 5215 pair->offset = offset + foff; 5216 pair->has_unknown_size = has_unknown_size; 5217 if (!has_unknown_size) 5218 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field)); 5219 else 5220 pair->size = -1; 5221 pair->must_have_pointers = must_have_pointers_p; 5222 pair->may_have_pointers = true; 5223 pair->only_restrict_pointers 5224 = (!has_unknown_size 5225 && POINTER_TYPE_P (TREE_TYPE (field)) 5226 && TYPE_RESTRICT (TREE_TYPE (field))); 5227 } 5228 } 5229 5230 empty_p = false; 5231 } 5232 5233 return !empty_p; 5234 } 5235 5236 /* Count the number of arguments DECL has, and set IS_VARARGS to true 5237 if it is a varargs function. */ 5238 5239 static unsigned int 5240 count_num_arguments (tree decl, bool *is_varargs) 5241 { 5242 unsigned int num = 0; 5243 tree t; 5244 5245 /* Capture named arguments for K&R functions. They do not 5246 have a prototype and thus no TYPE_ARG_TYPES. */ 5247 for (t = DECL_ARGUMENTS (decl); t; t = DECL_CHAIN (t)) 5248 ++num; 5249 5250 /* Check if the function has variadic arguments. */ 5251 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t)) 5252 if (TREE_VALUE (t) == void_type_node) 5253 break; 5254 if (!t) 5255 *is_varargs = true; 5256 5257 return num; 5258 } 5259 5260 /* Creation function node for DECL, using NAME, and return the index 5261 of the variable we've created for the function. */ 5262 5263 static varinfo_t 5264 create_function_info_for (tree decl, const char *name) 5265 { 5266 struct function *fn = DECL_STRUCT_FUNCTION (decl); 5267 varinfo_t vi, prev_vi; 5268 tree arg; 5269 unsigned int i; 5270 bool is_varargs = false; 5271 unsigned int num_args = count_num_arguments (decl, &is_varargs); 5272 5273 /* Create the variable info. */ 5274 5275 vi = new_var_info (decl, name); 5276 vi->offset = 0; 5277 vi->size = 1; 5278 vi->fullsize = fi_parm_base + num_args; 5279 vi->is_fn_info = 1; 5280 vi->may_have_pointers = false; 5281 if (is_varargs) 5282 vi->fullsize = ~0; 5283 insert_vi_for_tree (vi->decl, vi); 5284 5285 prev_vi = vi; 5286 5287 /* Create a variable for things the function clobbers and one for 5288 things the function uses. */ 5289 { 5290 varinfo_t clobbervi, usevi; 5291 const char *newname; 5292 char *tempname; 5293 5294 asprintf (&tempname, "%s.clobber", name); 5295 newname = ggc_strdup (tempname); 5296 free (tempname); 5297 5298 clobbervi = new_var_info (NULL, newname); 5299 clobbervi->offset = fi_clobbers; 5300 clobbervi->size = 1; 5301 clobbervi->fullsize = vi->fullsize; 5302 clobbervi->is_full_var = true; 5303 clobbervi->is_global_var = false; 5304 gcc_assert (prev_vi->offset < clobbervi->offset); 5305 prev_vi->next = clobbervi; 5306 prev_vi = clobbervi; 5307 5308 asprintf (&tempname, "%s.use", name); 5309 newname = ggc_strdup (tempname); 5310 free (tempname); 5311 5312 usevi = new_var_info (NULL, newname); 5313 usevi->offset = fi_uses; 5314 usevi->size = 1; 5315 usevi->fullsize = vi->fullsize; 5316 usevi->is_full_var = true; 5317 usevi->is_global_var = false; 5318 gcc_assert (prev_vi->offset < usevi->offset); 5319 prev_vi->next = usevi; 5320 prev_vi = usevi; 5321 } 5322 5323 /* And one for the static chain. */ 5324 if (fn->static_chain_decl != NULL_TREE) 5325 { 5326 varinfo_t chainvi; 5327 const char *newname; 5328 char *tempname; 5329 5330 asprintf (&tempname, "%s.chain", name); 5331 newname = ggc_strdup (tempname); 5332 free (tempname); 5333 5334 chainvi = new_var_info (fn->static_chain_decl, newname); 5335 chainvi->offset = fi_static_chain; 5336 chainvi->size = 1; 5337 chainvi->fullsize = vi->fullsize; 5338 chainvi->is_full_var = true; 5339 chainvi->is_global_var = false; 5340 gcc_assert (prev_vi->offset < chainvi->offset); 5341 prev_vi->next = chainvi; 5342 prev_vi = chainvi; 5343 insert_vi_for_tree (fn->static_chain_decl, chainvi); 5344 } 5345 5346 /* Create a variable for the return var. */ 5347 if (DECL_RESULT (decl) != NULL 5348 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl)))) 5349 { 5350 varinfo_t resultvi; 5351 const char *newname; 5352 char *tempname; 5353 tree resultdecl = decl; 5354 5355 if (DECL_RESULT (decl)) 5356 resultdecl = DECL_RESULT (decl); 5357 5358 asprintf (&tempname, "%s.result", name); 5359 newname = ggc_strdup (tempname); 5360 free (tempname); 5361 5362 resultvi = new_var_info (resultdecl, newname); 5363 resultvi->offset = fi_result; 5364 resultvi->size = 1; 5365 resultvi->fullsize = vi->fullsize; 5366 resultvi->is_full_var = true; 5367 if (DECL_RESULT (decl)) 5368 resultvi->may_have_pointers = true; 5369 gcc_assert (prev_vi->offset < resultvi->offset); 5370 prev_vi->next = resultvi; 5371 prev_vi = resultvi; 5372 if (DECL_RESULT (decl)) 5373 insert_vi_for_tree (DECL_RESULT (decl), resultvi); 5374 } 5375 5376 /* Set up variables for each argument. */ 5377 arg = DECL_ARGUMENTS (decl); 5378 for (i = 0; i < num_args; i++) 5379 { 5380 varinfo_t argvi; 5381 const char *newname; 5382 char *tempname; 5383 tree argdecl = decl; 5384 5385 if (arg) 5386 argdecl = arg; 5387 5388 asprintf (&tempname, "%s.arg%d", name, i); 5389 newname = ggc_strdup (tempname); 5390 free (tempname); 5391 5392 argvi = new_var_info (argdecl, newname); 5393 argvi->offset = fi_parm_base + i; 5394 argvi->size = 1; 5395 argvi->is_full_var = true; 5396 argvi->fullsize = vi->fullsize; 5397 if (arg) 5398 argvi->may_have_pointers = true; 5399 gcc_assert (prev_vi->offset < argvi->offset); 5400 prev_vi->next = argvi; 5401 prev_vi = argvi; 5402 if (arg) 5403 { 5404 insert_vi_for_tree (arg, argvi); 5405 arg = DECL_CHAIN (arg); 5406 } 5407 } 5408 5409 /* Add one representative for all further args. */ 5410 if (is_varargs) 5411 { 5412 varinfo_t argvi; 5413 const char *newname; 5414 char *tempname; 5415 tree decl; 5416 5417 asprintf (&tempname, "%s.varargs", name); 5418 newname = ggc_strdup (tempname); 5419 free (tempname); 5420 5421 /* We need sth that can be pointed to for va_start. */ 5422 decl = build_fake_var_decl (ptr_type_node); 5423 5424 argvi = new_var_info (decl, newname); 5425 argvi->offset = fi_parm_base + num_args; 5426 argvi->size = ~0; 5427 argvi->is_full_var = true; 5428 argvi->is_heap_var = true; 5429 argvi->fullsize = vi->fullsize; 5430 gcc_assert (prev_vi->offset < argvi->offset); 5431 prev_vi->next = argvi; 5432 prev_vi = argvi; 5433 } 5434 5435 return vi; 5436 } 5437 5438 5439 /* Return true if FIELDSTACK contains fields that overlap. 5440 FIELDSTACK is assumed to be sorted by offset. */ 5441 5442 static bool 5443 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack) 5444 { 5445 fieldoff_s *fo = NULL; 5446 unsigned int i; 5447 HOST_WIDE_INT lastoffset = -1; 5448 5449 FOR_EACH_VEC_ELT (fieldoff_s, fieldstack, i, fo) 5450 { 5451 if (fo->offset == lastoffset) 5452 return true; 5453 lastoffset = fo->offset; 5454 } 5455 return false; 5456 } 5457 5458 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP. 5459 This will also create any varinfo structures necessary for fields 5460 of DECL. */ 5461 5462 static varinfo_t 5463 create_variable_info_for_1 (tree decl, const char *name) 5464 { 5465 varinfo_t vi, newvi; 5466 tree decl_type = TREE_TYPE (decl); 5467 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type); 5468 VEC (fieldoff_s,heap) *fieldstack = NULL; 5469 fieldoff_s *fo; 5470 unsigned int i; 5471 5472 if (!declsize 5473 || !host_integerp (declsize, 1)) 5474 { 5475 vi = new_var_info (decl, name); 5476 vi->offset = 0; 5477 vi->size = ~0; 5478 vi->fullsize = ~0; 5479 vi->is_unknown_size_var = true; 5480 vi->is_full_var = true; 5481 vi->may_have_pointers = true; 5482 return vi; 5483 } 5484 5485 /* Collect field information. */ 5486 if (use_field_sensitive 5487 && var_can_have_subvars (decl) 5488 /* ??? Force us to not use subfields for global initializers 5489 in IPA mode. Else we'd have to parse arbitrary initializers. */ 5490 && !(in_ipa_mode 5491 && is_global_var (decl) 5492 && DECL_INITIAL (decl))) 5493 { 5494 fieldoff_s *fo = NULL; 5495 bool notokay = false; 5496 unsigned int i; 5497 5498 push_fields_onto_fieldstack (decl_type, &fieldstack, 0); 5499 5500 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++) 5501 if (fo->has_unknown_size 5502 || fo->offset < 0) 5503 { 5504 notokay = true; 5505 break; 5506 } 5507 5508 /* We can't sort them if we have a field with a variable sized type, 5509 which will make notokay = true. In that case, we are going to return 5510 without creating varinfos for the fields anyway, so sorting them is a 5511 waste to boot. */ 5512 if (!notokay) 5513 { 5514 sort_fieldstack (fieldstack); 5515 /* Due to some C++ FE issues, like PR 22488, we might end up 5516 what appear to be overlapping fields even though they, 5517 in reality, do not overlap. Until the C++ FE is fixed, 5518 we will simply disable field-sensitivity for these cases. */ 5519 notokay = check_for_overlaps (fieldstack); 5520 } 5521 5522 if (notokay) 5523 VEC_free (fieldoff_s, heap, fieldstack); 5524 } 5525 5526 /* If we didn't end up collecting sub-variables create a full 5527 variable for the decl. */ 5528 if (VEC_length (fieldoff_s, fieldstack) <= 1 5529 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE) 5530 { 5531 vi = new_var_info (decl, name); 5532 vi->offset = 0; 5533 vi->may_have_pointers = true; 5534 vi->fullsize = TREE_INT_CST_LOW (declsize); 5535 vi->size = vi->fullsize; 5536 vi->is_full_var = true; 5537 VEC_free (fieldoff_s, heap, fieldstack); 5538 return vi; 5539 } 5540 5541 vi = new_var_info (decl, name); 5542 vi->fullsize = TREE_INT_CST_LOW (declsize); 5543 for (i = 0, newvi = vi; 5544 VEC_iterate (fieldoff_s, fieldstack, i, fo); 5545 ++i, newvi = newvi->next) 5546 { 5547 const char *newname = "NULL"; 5548 char *tempname; 5549 5550 if (dump_file) 5551 { 5552 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC 5553 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size); 5554 newname = ggc_strdup (tempname); 5555 free (tempname); 5556 } 5557 newvi->name = newname; 5558 newvi->offset = fo->offset; 5559 newvi->size = fo->size; 5560 newvi->fullsize = vi->fullsize; 5561 newvi->may_have_pointers = fo->may_have_pointers; 5562 newvi->only_restrict_pointers = fo->only_restrict_pointers; 5563 if (i + 1 < VEC_length (fieldoff_s, fieldstack)) 5564 newvi->next = new_var_info (decl, name); 5565 } 5566 5567 VEC_free (fieldoff_s, heap, fieldstack); 5568 5569 return vi; 5570 } 5571 5572 static unsigned int 5573 create_variable_info_for (tree decl, const char *name) 5574 { 5575 varinfo_t vi = create_variable_info_for_1 (decl, name); 5576 unsigned int id = vi->id; 5577 5578 insert_vi_for_tree (decl, vi); 5579 5580 if (TREE_CODE (decl) != VAR_DECL) 5581 return id; 5582 5583 /* Create initial constraints for globals. */ 5584 for (; vi; vi = vi->next) 5585 { 5586 if (!vi->may_have_pointers 5587 || !vi->is_global_var) 5588 continue; 5589 5590 /* Mark global restrict qualified pointers. */ 5591 if ((POINTER_TYPE_P (TREE_TYPE (decl)) 5592 && TYPE_RESTRICT (TREE_TYPE (decl))) 5593 || vi->only_restrict_pointers) 5594 { 5595 make_constraint_from_global_restrict (vi, "GLOBAL_RESTRICT"); 5596 continue; 5597 } 5598 5599 /* In non-IPA mode the initializer from nonlocal is all we need. */ 5600 if (!in_ipa_mode 5601 || DECL_HARD_REGISTER (decl)) 5602 make_copy_constraint (vi, nonlocal_id); 5603 5604 /* In IPA mode parse the initializer and generate proper constraints 5605 for it. */ 5606 else 5607 { 5608 struct varpool_node *vnode = varpool_get_node (decl); 5609 5610 /* For escaped variables initialize them from nonlocal. */ 5611 if (!varpool_all_refs_explicit_p (vnode)) 5612 make_copy_constraint (vi, nonlocal_id); 5613 5614 /* If this is a global variable with an initializer and we are in 5615 IPA mode generate constraints for it. */ 5616 if (DECL_INITIAL (decl)) 5617 { 5618 VEC (ce_s, heap) *rhsc = NULL; 5619 struct constraint_expr lhs, *rhsp; 5620 unsigned i; 5621 get_constraint_for_rhs (DECL_INITIAL (decl), &rhsc); 5622 lhs.var = vi->id; 5623 lhs.offset = 0; 5624 lhs.type = SCALAR; 5625 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp) 5626 process_constraint (new_constraint (lhs, *rhsp)); 5627 /* If this is a variable that escapes from the unit 5628 the initializer escapes as well. */ 5629 if (!varpool_all_refs_explicit_p (vnode)) 5630 { 5631 lhs.var = escaped_id; 5632 lhs.offset = 0; 5633 lhs.type = SCALAR; 5634 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp) 5635 process_constraint (new_constraint (lhs, *rhsp)); 5636 } 5637 VEC_free (ce_s, heap, rhsc); 5638 } 5639 } 5640 } 5641 5642 return id; 5643 } 5644 5645 /* Print out the points-to solution for VAR to FILE. */ 5646 5647 static void 5648 dump_solution_for_var (FILE *file, unsigned int var) 5649 { 5650 varinfo_t vi = get_varinfo (var); 5651 unsigned int i; 5652 bitmap_iterator bi; 5653 5654 /* Dump the solution for unified vars anyway, this avoids difficulties 5655 in scanning dumps in the testsuite. */ 5656 fprintf (file, "%s = { ", vi->name); 5657 vi = get_varinfo (find (var)); 5658 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi) 5659 fprintf (file, "%s ", get_varinfo (i)->name); 5660 fprintf (file, "}"); 5661 5662 /* But note when the variable was unified. */ 5663 if (vi->id != var) 5664 fprintf (file, " same as %s", vi->name); 5665 5666 fprintf (file, "\n"); 5667 } 5668 5669 /* Print the points-to solution for VAR to stdout. */ 5670 5671 DEBUG_FUNCTION void 5672 debug_solution_for_var (unsigned int var) 5673 { 5674 dump_solution_for_var (stdout, var); 5675 } 5676 5677 /* Create varinfo structures for all of the variables in the 5678 function for intraprocedural mode. */ 5679 5680 static void 5681 intra_create_variable_infos (void) 5682 { 5683 tree t; 5684 5685 /* For each incoming pointer argument arg, create the constraint ARG 5686 = NONLOCAL or a dummy variable if it is a restrict qualified 5687 passed-by-reference argument. */ 5688 for (t = DECL_ARGUMENTS (current_function_decl); t; t = DECL_CHAIN (t)) 5689 { 5690 varinfo_t p = get_vi_for_tree (t); 5691 5692 /* For restrict qualified pointers to objects passed by 5693 reference build a real representative for the pointed-to object. 5694 Treat restrict qualified references the same. */ 5695 if (TYPE_RESTRICT (TREE_TYPE (t)) 5696 && ((DECL_BY_REFERENCE (t) && POINTER_TYPE_P (TREE_TYPE (t))) 5697 || TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) 5698 && !type_contains_placeholder_p (TREE_TYPE (TREE_TYPE (t)))) 5699 { 5700 struct constraint_expr lhsc, rhsc; 5701 varinfo_t vi; 5702 tree heapvar = build_fake_var_decl (TREE_TYPE (TREE_TYPE (t))); 5703 DECL_EXTERNAL (heapvar) = 1; 5704 vi = create_variable_info_for_1 (heapvar, "PARM_NOALIAS"); 5705 insert_vi_for_tree (heapvar, vi); 5706 lhsc.var = p->id; 5707 lhsc.type = SCALAR; 5708 lhsc.offset = 0; 5709 rhsc.var = vi->id; 5710 rhsc.type = ADDRESSOF; 5711 rhsc.offset = 0; 5712 process_constraint (new_constraint (lhsc, rhsc)); 5713 for (; vi; vi = vi->next) 5714 if (vi->may_have_pointers) 5715 { 5716 if (vi->only_restrict_pointers) 5717 make_constraint_from_global_restrict (vi, "GLOBAL_RESTRICT"); 5718 else 5719 make_copy_constraint (vi, nonlocal_id); 5720 } 5721 continue; 5722 } 5723 5724 if (POINTER_TYPE_P (TREE_TYPE (t)) 5725 && TYPE_RESTRICT (TREE_TYPE (t))) 5726 make_constraint_from_global_restrict (p, "PARM_RESTRICT"); 5727 else 5728 { 5729 for (; p; p = p->next) 5730 { 5731 if (p->only_restrict_pointers) 5732 make_constraint_from_global_restrict (p, "PARM_RESTRICT"); 5733 else if (p->may_have_pointers) 5734 make_constraint_from (p, nonlocal_id); 5735 } 5736 } 5737 } 5738 5739 /* Add a constraint for a result decl that is passed by reference. */ 5740 if (DECL_RESULT (cfun->decl) 5741 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl))) 5742 { 5743 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl)); 5744 5745 for (p = result_vi; p; p = p->next) 5746 make_constraint_from (p, nonlocal_id); 5747 } 5748 5749 /* Add a constraint for the incoming static chain parameter. */ 5750 if (cfun->static_chain_decl != NULL_TREE) 5751 { 5752 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl); 5753 5754 for (p = chain_vi; p; p = p->next) 5755 make_constraint_from (p, nonlocal_id); 5756 } 5757 } 5758 5759 /* Structure used to put solution bitmaps in a hashtable so they can 5760 be shared among variables with the same points-to set. */ 5761 5762 typedef struct shared_bitmap_info 5763 { 5764 bitmap pt_vars; 5765 hashval_t hashcode; 5766 } *shared_bitmap_info_t; 5767 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t; 5768 5769 static htab_t shared_bitmap_table; 5770 5771 /* Hash function for a shared_bitmap_info_t */ 5772 5773 static hashval_t 5774 shared_bitmap_hash (const void *p) 5775 { 5776 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p; 5777 return bi->hashcode; 5778 } 5779 5780 /* Equality function for two shared_bitmap_info_t's. */ 5781 5782 static int 5783 shared_bitmap_eq (const void *p1, const void *p2) 5784 { 5785 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1; 5786 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2; 5787 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars); 5788 } 5789 5790 /* Lookup a bitmap in the shared bitmap hashtable, and return an already 5791 existing instance if there is one, NULL otherwise. */ 5792 5793 static bitmap 5794 shared_bitmap_lookup (bitmap pt_vars) 5795 { 5796 void **slot; 5797 struct shared_bitmap_info sbi; 5798 5799 sbi.pt_vars = pt_vars; 5800 sbi.hashcode = bitmap_hash (pt_vars); 5801 5802 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi, 5803 sbi.hashcode, NO_INSERT); 5804 if (!slot) 5805 return NULL; 5806 else 5807 return ((shared_bitmap_info_t) *slot)->pt_vars; 5808 } 5809 5810 5811 /* Add a bitmap to the shared bitmap hashtable. */ 5812 5813 static void 5814 shared_bitmap_add (bitmap pt_vars) 5815 { 5816 void **slot; 5817 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info); 5818 5819 sbi->pt_vars = pt_vars; 5820 sbi->hashcode = bitmap_hash (pt_vars); 5821 5822 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi, 5823 sbi->hashcode, INSERT); 5824 gcc_assert (!*slot); 5825 *slot = (void *) sbi; 5826 } 5827 5828 5829 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */ 5830 5831 static void 5832 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt) 5833 { 5834 unsigned int i; 5835 bitmap_iterator bi; 5836 5837 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi) 5838 { 5839 varinfo_t vi = get_varinfo (i); 5840 5841 /* The only artificial variables that are allowed in a may-alias 5842 set are heap variables. */ 5843 if (vi->is_artificial_var && !vi->is_heap_var) 5844 continue; 5845 5846 if (TREE_CODE (vi->decl) == VAR_DECL 5847 || TREE_CODE (vi->decl) == PARM_DECL 5848 || TREE_CODE (vi->decl) == RESULT_DECL) 5849 { 5850 /* If we are in IPA mode we will not recompute points-to 5851 sets after inlining so make sure they stay valid. */ 5852 if (in_ipa_mode 5853 && !DECL_PT_UID_SET_P (vi->decl)) 5854 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl)); 5855 5856 /* Add the decl to the points-to set. Note that the points-to 5857 set contains global variables. */ 5858 bitmap_set_bit (into, DECL_PT_UID (vi->decl)); 5859 if (vi->is_global_var) 5860 pt->vars_contains_global = true; 5861 } 5862 } 5863 } 5864 5865 5866 /* Compute the points-to solution *PT for the variable VI. */ 5867 5868 static void 5869 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt) 5870 { 5871 unsigned int i; 5872 bitmap_iterator bi; 5873 bitmap finished_solution; 5874 bitmap result; 5875 varinfo_t vi; 5876 5877 memset (pt, 0, sizeof (struct pt_solution)); 5878 5879 /* This variable may have been collapsed, let's get the real 5880 variable. */ 5881 vi = get_varinfo (find (orig_vi->id)); 5882 5883 /* Translate artificial variables into SSA_NAME_PTR_INFO 5884 attributes. */ 5885 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi) 5886 { 5887 varinfo_t vi = get_varinfo (i); 5888 5889 if (vi->is_artificial_var) 5890 { 5891 if (vi->id == nothing_id) 5892 pt->null = 1; 5893 else if (vi->id == escaped_id) 5894 { 5895 if (in_ipa_mode) 5896 pt->ipa_escaped = 1; 5897 else 5898 pt->escaped = 1; 5899 } 5900 else if (vi->id == nonlocal_id) 5901 pt->nonlocal = 1; 5902 else if (vi->is_heap_var) 5903 /* We represent heapvars in the points-to set properly. */ 5904 ; 5905 else if (vi->id == readonly_id) 5906 /* Nobody cares. */ 5907 ; 5908 else if (vi->id == anything_id 5909 || vi->id == integer_id) 5910 pt->anything = 1; 5911 } 5912 } 5913 5914 /* Instead of doing extra work, simply do not create 5915 elaborate points-to information for pt_anything pointers. */ 5916 if (pt->anything) 5917 return; 5918 5919 /* Share the final set of variables when possible. */ 5920 finished_solution = BITMAP_GGC_ALLOC (); 5921 stats.points_to_sets_created++; 5922 5923 set_uids_in_ptset (finished_solution, vi->solution, pt); 5924 result = shared_bitmap_lookup (finished_solution); 5925 if (!result) 5926 { 5927 shared_bitmap_add (finished_solution); 5928 pt->vars = finished_solution; 5929 } 5930 else 5931 { 5932 pt->vars = result; 5933 bitmap_clear (finished_solution); 5934 } 5935 } 5936 5937 /* Given a pointer variable P, fill in its points-to set. */ 5938 5939 static void 5940 find_what_p_points_to (tree p) 5941 { 5942 struct ptr_info_def *pi; 5943 tree lookup_p = p; 5944 varinfo_t vi; 5945 5946 /* For parameters, get at the points-to set for the actual parm 5947 decl. */ 5948 if (TREE_CODE (p) == SSA_NAME 5949 && (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL 5950 || TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL) 5951 && SSA_NAME_IS_DEFAULT_DEF (p)) 5952 lookup_p = SSA_NAME_VAR (p); 5953 5954 vi = lookup_vi_for_tree (lookup_p); 5955 if (!vi) 5956 return; 5957 5958 pi = get_ptr_info (p); 5959 find_what_var_points_to (vi, &pi->pt); 5960 } 5961 5962 5963 /* Query statistics for points-to solutions. */ 5964 5965 static struct { 5966 unsigned HOST_WIDE_INT pt_solution_includes_may_alias; 5967 unsigned HOST_WIDE_INT pt_solution_includes_no_alias; 5968 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias; 5969 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias; 5970 } pta_stats; 5971 5972 void 5973 dump_pta_stats (FILE *s) 5974 { 5975 fprintf (s, "\nPTA query stats:\n"); 5976 fprintf (s, " pt_solution_includes: " 5977 HOST_WIDE_INT_PRINT_DEC" disambiguations, " 5978 HOST_WIDE_INT_PRINT_DEC" queries\n", 5979 pta_stats.pt_solution_includes_no_alias, 5980 pta_stats.pt_solution_includes_no_alias 5981 + pta_stats.pt_solution_includes_may_alias); 5982 fprintf (s, " pt_solutions_intersect: " 5983 HOST_WIDE_INT_PRINT_DEC" disambiguations, " 5984 HOST_WIDE_INT_PRINT_DEC" queries\n", 5985 pta_stats.pt_solutions_intersect_no_alias, 5986 pta_stats.pt_solutions_intersect_no_alias 5987 + pta_stats.pt_solutions_intersect_may_alias); 5988 } 5989 5990 5991 /* Reset the points-to solution *PT to a conservative default 5992 (point to anything). */ 5993 5994 void 5995 pt_solution_reset (struct pt_solution *pt) 5996 { 5997 memset (pt, 0, sizeof (struct pt_solution)); 5998 pt->anything = true; 5999 } 6000 6001 /* Set the points-to solution *PT to point only to the variables 6002 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains 6003 global variables and VARS_CONTAINS_RESTRICT specifies whether 6004 it contains restrict tag variables. */ 6005 6006 void 6007 pt_solution_set (struct pt_solution *pt, bitmap vars, bool vars_contains_global) 6008 { 6009 memset (pt, 0, sizeof (struct pt_solution)); 6010 pt->vars = vars; 6011 pt->vars_contains_global = vars_contains_global; 6012 } 6013 6014 /* Set the points-to solution *PT to point only to the variable VAR. */ 6015 6016 void 6017 pt_solution_set_var (struct pt_solution *pt, tree var) 6018 { 6019 memset (pt, 0, sizeof (struct pt_solution)); 6020 pt->vars = BITMAP_GGC_ALLOC (); 6021 bitmap_set_bit (pt->vars, DECL_PT_UID (var)); 6022 pt->vars_contains_global = is_global_var (var); 6023 } 6024 6025 /* Computes the union of the points-to solutions *DEST and *SRC and 6026 stores the result in *DEST. This changes the points-to bitmap 6027 of *DEST and thus may not be used if that might be shared. 6028 The points-to bitmap of *SRC and *DEST will not be shared after 6029 this function if they were not before. */ 6030 6031 static void 6032 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src) 6033 { 6034 dest->anything |= src->anything; 6035 if (dest->anything) 6036 { 6037 pt_solution_reset (dest); 6038 return; 6039 } 6040 6041 dest->nonlocal |= src->nonlocal; 6042 dest->escaped |= src->escaped; 6043 dest->ipa_escaped |= src->ipa_escaped; 6044 dest->null |= src->null; 6045 dest->vars_contains_global |= src->vars_contains_global; 6046 if (!src->vars) 6047 return; 6048 6049 if (!dest->vars) 6050 dest->vars = BITMAP_GGC_ALLOC (); 6051 bitmap_ior_into (dest->vars, src->vars); 6052 } 6053 6054 /* Return true if the points-to solution *PT is empty. */ 6055 6056 bool 6057 pt_solution_empty_p (struct pt_solution *pt) 6058 { 6059 if (pt->anything 6060 || pt->nonlocal) 6061 return false; 6062 6063 if (pt->vars 6064 && !bitmap_empty_p (pt->vars)) 6065 return false; 6066 6067 /* If the solution includes ESCAPED, check if that is empty. */ 6068 if (pt->escaped 6069 && !pt_solution_empty_p (&cfun->gimple_df->escaped)) 6070 return false; 6071 6072 /* If the solution includes ESCAPED, check if that is empty. */ 6073 if (pt->ipa_escaped 6074 && !pt_solution_empty_p (&ipa_escaped_pt)) 6075 return false; 6076 6077 return true; 6078 } 6079 6080 /* Return true if the points-to solution *PT only point to a single var, and 6081 return the var uid in *UID. */ 6082 6083 bool 6084 pt_solution_singleton_p (struct pt_solution *pt, unsigned *uid) 6085 { 6086 if (pt->anything || pt->nonlocal || pt->escaped || pt->ipa_escaped 6087 || pt->null || pt->vars == NULL 6088 || !bitmap_single_bit_set_p (pt->vars)) 6089 return false; 6090 6091 *uid = bitmap_first_set_bit (pt->vars); 6092 return true; 6093 } 6094 6095 /* Return true if the points-to solution *PT includes global memory. */ 6096 6097 bool 6098 pt_solution_includes_global (struct pt_solution *pt) 6099 { 6100 if (pt->anything 6101 || pt->nonlocal 6102 || pt->vars_contains_global) 6103 return true; 6104 6105 if (pt->escaped) 6106 return pt_solution_includes_global (&cfun->gimple_df->escaped); 6107 6108 if (pt->ipa_escaped) 6109 return pt_solution_includes_global (&ipa_escaped_pt); 6110 6111 /* ??? This predicate is not correct for the IPA-PTA solution 6112 as we do not properly distinguish between unit escape points 6113 and global variables. */ 6114 if (cfun->gimple_df->ipa_pta) 6115 return true; 6116 6117 return false; 6118 } 6119 6120 /* Return true if the points-to solution *PT includes the variable 6121 declaration DECL. */ 6122 6123 static bool 6124 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl) 6125 { 6126 if (pt->anything) 6127 return true; 6128 6129 if (pt->nonlocal 6130 && is_global_var (decl)) 6131 return true; 6132 6133 if (pt->vars 6134 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl))) 6135 return true; 6136 6137 /* If the solution includes ESCAPED, check it. */ 6138 if (pt->escaped 6139 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl)) 6140 return true; 6141 6142 /* If the solution includes ESCAPED, check it. */ 6143 if (pt->ipa_escaped 6144 && pt_solution_includes_1 (&ipa_escaped_pt, decl)) 6145 return true; 6146 6147 return false; 6148 } 6149 6150 bool 6151 pt_solution_includes (struct pt_solution *pt, const_tree decl) 6152 { 6153 bool res = pt_solution_includes_1 (pt, decl); 6154 if (res) 6155 ++pta_stats.pt_solution_includes_may_alias; 6156 else 6157 ++pta_stats.pt_solution_includes_no_alias; 6158 return res; 6159 } 6160 6161 /* Return true if both points-to solutions PT1 and PT2 have a non-empty 6162 intersection. */ 6163 6164 static bool 6165 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2) 6166 { 6167 if (pt1->anything || pt2->anything) 6168 return true; 6169 6170 /* If either points to unknown global memory and the other points to 6171 any global memory they alias. */ 6172 if ((pt1->nonlocal 6173 && (pt2->nonlocal 6174 || pt2->vars_contains_global)) 6175 || (pt2->nonlocal 6176 && pt1->vars_contains_global)) 6177 return true; 6178 6179 /* Check the escaped solution if required. */ 6180 if ((pt1->escaped || pt2->escaped) 6181 && !pt_solution_empty_p (&cfun->gimple_df->escaped)) 6182 { 6183 /* If both point to escaped memory and that solution 6184 is not empty they alias. */ 6185 if (pt1->escaped && pt2->escaped) 6186 return true; 6187 6188 /* If either points to escaped memory see if the escaped solution 6189 intersects with the other. */ 6190 if ((pt1->escaped 6191 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2)) 6192 || (pt2->escaped 6193 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1))) 6194 return true; 6195 } 6196 6197 /* Check the escaped solution if required. 6198 ??? Do we need to check the local against the IPA escaped sets? */ 6199 if ((pt1->ipa_escaped || pt2->ipa_escaped) 6200 && !pt_solution_empty_p (&ipa_escaped_pt)) 6201 { 6202 /* If both point to escaped memory and that solution 6203 is not empty they alias. */ 6204 if (pt1->ipa_escaped && pt2->ipa_escaped) 6205 return true; 6206 6207 /* If either points to escaped memory see if the escaped solution 6208 intersects with the other. */ 6209 if ((pt1->ipa_escaped 6210 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2)) 6211 || (pt2->ipa_escaped 6212 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1))) 6213 return true; 6214 } 6215 6216 /* Now both pointers alias if their points-to solution intersects. */ 6217 return (pt1->vars 6218 && pt2->vars 6219 && bitmap_intersect_p (pt1->vars, pt2->vars)); 6220 } 6221 6222 bool 6223 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2) 6224 { 6225 bool res = pt_solutions_intersect_1 (pt1, pt2); 6226 if (res) 6227 ++pta_stats.pt_solutions_intersect_may_alias; 6228 else 6229 ++pta_stats.pt_solutions_intersect_no_alias; 6230 return res; 6231 } 6232 6233 6234 /* Dump points-to information to OUTFILE. */ 6235 6236 static void 6237 dump_sa_points_to_info (FILE *outfile) 6238 { 6239 unsigned int i; 6240 6241 fprintf (outfile, "\nPoints-to sets\n\n"); 6242 6243 if (dump_flags & TDF_STATS) 6244 { 6245 fprintf (outfile, "Stats:\n"); 6246 fprintf (outfile, "Total vars: %d\n", stats.total_vars); 6247 fprintf (outfile, "Non-pointer vars: %d\n", 6248 stats.nonpointer_vars); 6249 fprintf (outfile, "Statically unified vars: %d\n", 6250 stats.unified_vars_static); 6251 fprintf (outfile, "Dynamically unified vars: %d\n", 6252 stats.unified_vars_dynamic); 6253 fprintf (outfile, "Iterations: %d\n", stats.iterations); 6254 fprintf (outfile, "Number of edges: %d\n", stats.num_edges); 6255 fprintf (outfile, "Number of implicit edges: %d\n", 6256 stats.num_implicit_edges); 6257 } 6258 6259 for (i = 0; i < VEC_length (varinfo_t, varmap); i++) 6260 { 6261 varinfo_t vi = get_varinfo (i); 6262 if (!vi->may_have_pointers) 6263 continue; 6264 dump_solution_for_var (outfile, i); 6265 } 6266 } 6267 6268 6269 /* Debug points-to information to stderr. */ 6270 6271 DEBUG_FUNCTION void 6272 debug_sa_points_to_info (void) 6273 { 6274 dump_sa_points_to_info (stderr); 6275 } 6276 6277 6278 /* Initialize the always-existing constraint variables for NULL 6279 ANYTHING, READONLY, and INTEGER */ 6280 6281 static void 6282 init_base_vars (void) 6283 { 6284 struct constraint_expr lhs, rhs; 6285 varinfo_t var_anything; 6286 varinfo_t var_nothing; 6287 varinfo_t var_readonly; 6288 varinfo_t var_escaped; 6289 varinfo_t var_nonlocal; 6290 varinfo_t var_storedanything; 6291 varinfo_t var_integer; 6292 6293 /* Create the NULL variable, used to represent that a variable points 6294 to NULL. */ 6295 var_nothing = new_var_info (NULL_TREE, "NULL"); 6296 gcc_assert (var_nothing->id == nothing_id); 6297 var_nothing->is_artificial_var = 1; 6298 var_nothing->offset = 0; 6299 var_nothing->size = ~0; 6300 var_nothing->fullsize = ~0; 6301 var_nothing->is_special_var = 1; 6302 var_nothing->may_have_pointers = 0; 6303 var_nothing->is_global_var = 0; 6304 6305 /* Create the ANYTHING variable, used to represent that a variable 6306 points to some unknown piece of memory. */ 6307 var_anything = new_var_info (NULL_TREE, "ANYTHING"); 6308 gcc_assert (var_anything->id == anything_id); 6309 var_anything->is_artificial_var = 1; 6310 var_anything->size = ~0; 6311 var_anything->offset = 0; 6312 var_anything->next = NULL; 6313 var_anything->fullsize = ~0; 6314 var_anything->is_special_var = 1; 6315 6316 /* Anything points to anything. This makes deref constraints just 6317 work in the presence of linked list and other p = *p type loops, 6318 by saying that *ANYTHING = ANYTHING. */ 6319 lhs.type = SCALAR; 6320 lhs.var = anything_id; 6321 lhs.offset = 0; 6322 rhs.type = ADDRESSOF; 6323 rhs.var = anything_id; 6324 rhs.offset = 0; 6325 6326 /* This specifically does not use process_constraint because 6327 process_constraint ignores all anything = anything constraints, since all 6328 but this one are redundant. */ 6329 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs)); 6330 6331 /* Create the READONLY variable, used to represent that a variable 6332 points to readonly memory. */ 6333 var_readonly = new_var_info (NULL_TREE, "READONLY"); 6334 gcc_assert (var_readonly->id == readonly_id); 6335 var_readonly->is_artificial_var = 1; 6336 var_readonly->offset = 0; 6337 var_readonly->size = ~0; 6338 var_readonly->fullsize = ~0; 6339 var_readonly->next = NULL; 6340 var_readonly->is_special_var = 1; 6341 6342 /* readonly memory points to anything, in order to make deref 6343 easier. In reality, it points to anything the particular 6344 readonly variable can point to, but we don't track this 6345 separately. */ 6346 lhs.type = SCALAR; 6347 lhs.var = readonly_id; 6348 lhs.offset = 0; 6349 rhs.type = ADDRESSOF; 6350 rhs.var = readonly_id; /* FIXME */ 6351 rhs.offset = 0; 6352 process_constraint (new_constraint (lhs, rhs)); 6353 6354 /* Create the ESCAPED variable, used to represent the set of escaped 6355 memory. */ 6356 var_escaped = new_var_info (NULL_TREE, "ESCAPED"); 6357 gcc_assert (var_escaped->id == escaped_id); 6358 var_escaped->is_artificial_var = 1; 6359 var_escaped->offset = 0; 6360 var_escaped->size = ~0; 6361 var_escaped->fullsize = ~0; 6362 var_escaped->is_special_var = 0; 6363 6364 /* Create the NONLOCAL variable, used to represent the set of nonlocal 6365 memory. */ 6366 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL"); 6367 gcc_assert (var_nonlocal->id == nonlocal_id); 6368 var_nonlocal->is_artificial_var = 1; 6369 var_nonlocal->offset = 0; 6370 var_nonlocal->size = ~0; 6371 var_nonlocal->fullsize = ~0; 6372 var_nonlocal->is_special_var = 1; 6373 6374 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */ 6375 lhs.type = SCALAR; 6376 lhs.var = escaped_id; 6377 lhs.offset = 0; 6378 rhs.type = DEREF; 6379 rhs.var = escaped_id; 6380 rhs.offset = 0; 6381 process_constraint (new_constraint (lhs, rhs)); 6382 6383 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the 6384 whole variable escapes. */ 6385 lhs.type = SCALAR; 6386 lhs.var = escaped_id; 6387 lhs.offset = 0; 6388 rhs.type = SCALAR; 6389 rhs.var = escaped_id; 6390 rhs.offset = UNKNOWN_OFFSET; 6391 process_constraint (new_constraint (lhs, rhs)); 6392 6393 /* *ESCAPED = NONLOCAL. This is true because we have to assume 6394 everything pointed to by escaped points to what global memory can 6395 point to. */ 6396 lhs.type = DEREF; 6397 lhs.var = escaped_id; 6398 lhs.offset = 0; 6399 rhs.type = SCALAR; 6400 rhs.var = nonlocal_id; 6401 rhs.offset = 0; 6402 process_constraint (new_constraint (lhs, rhs)); 6403 6404 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because 6405 global memory may point to global memory and escaped memory. */ 6406 lhs.type = SCALAR; 6407 lhs.var = nonlocal_id; 6408 lhs.offset = 0; 6409 rhs.type = ADDRESSOF; 6410 rhs.var = nonlocal_id; 6411 rhs.offset = 0; 6412 process_constraint (new_constraint (lhs, rhs)); 6413 rhs.type = ADDRESSOF; 6414 rhs.var = escaped_id; 6415 rhs.offset = 0; 6416 process_constraint (new_constraint (lhs, rhs)); 6417 6418 /* Create the STOREDANYTHING variable, used to represent the set of 6419 variables stored to *ANYTHING. */ 6420 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING"); 6421 gcc_assert (var_storedanything->id == storedanything_id); 6422 var_storedanything->is_artificial_var = 1; 6423 var_storedanything->offset = 0; 6424 var_storedanything->size = ~0; 6425 var_storedanything->fullsize = ~0; 6426 var_storedanything->is_special_var = 0; 6427 6428 /* Create the INTEGER variable, used to represent that a variable points 6429 to what an INTEGER "points to". */ 6430 var_integer = new_var_info (NULL_TREE, "INTEGER"); 6431 gcc_assert (var_integer->id == integer_id); 6432 var_integer->is_artificial_var = 1; 6433 var_integer->size = ~0; 6434 var_integer->fullsize = ~0; 6435 var_integer->offset = 0; 6436 var_integer->next = NULL; 6437 var_integer->is_special_var = 1; 6438 6439 /* INTEGER = ANYTHING, because we don't know where a dereference of 6440 a random integer will point to. */ 6441 lhs.type = SCALAR; 6442 lhs.var = integer_id; 6443 lhs.offset = 0; 6444 rhs.type = ADDRESSOF; 6445 rhs.var = anything_id; 6446 rhs.offset = 0; 6447 process_constraint (new_constraint (lhs, rhs)); 6448 } 6449 6450 /* Initialize things necessary to perform PTA */ 6451 6452 static void 6453 init_alias_vars (void) 6454 { 6455 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1); 6456 6457 bitmap_obstack_initialize (&pta_obstack); 6458 bitmap_obstack_initialize (&oldpta_obstack); 6459 bitmap_obstack_initialize (&predbitmap_obstack); 6460 6461 constraint_pool = create_alloc_pool ("Constraint pool", 6462 sizeof (struct constraint), 30); 6463 variable_info_pool = create_alloc_pool ("Variable info pool", 6464 sizeof (struct variable_info), 30); 6465 constraints = VEC_alloc (constraint_t, heap, 8); 6466 varmap = VEC_alloc (varinfo_t, heap, 8); 6467 vi_for_tree = pointer_map_create (); 6468 call_stmt_vars = pointer_map_create (); 6469 6470 memset (&stats, 0, sizeof (stats)); 6471 shared_bitmap_table = htab_create (511, shared_bitmap_hash, 6472 shared_bitmap_eq, free); 6473 init_base_vars (); 6474 6475 gcc_obstack_init (&fake_var_decl_obstack); 6476 } 6477 6478 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the 6479 predecessor edges. */ 6480 6481 static void 6482 remove_preds_and_fake_succs (constraint_graph_t graph) 6483 { 6484 unsigned int i; 6485 6486 /* Clear the implicit ref and address nodes from the successor 6487 lists. */ 6488 for (i = 0; i < FIRST_REF_NODE; i++) 6489 { 6490 if (graph->succs[i]) 6491 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE, 6492 FIRST_REF_NODE * 2); 6493 } 6494 6495 /* Free the successor list for the non-ref nodes. */ 6496 for (i = FIRST_REF_NODE; i < graph->size; i++) 6497 { 6498 if (graph->succs[i]) 6499 BITMAP_FREE (graph->succs[i]); 6500 } 6501 6502 /* Now reallocate the size of the successor list as, and blow away 6503 the predecessor bitmaps. */ 6504 graph->size = VEC_length (varinfo_t, varmap); 6505 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size); 6506 6507 free (graph->implicit_preds); 6508 graph->implicit_preds = NULL; 6509 free (graph->preds); 6510 graph->preds = NULL; 6511 bitmap_obstack_release (&predbitmap_obstack); 6512 } 6513 6514 /* Solve the constraint set. */ 6515 6516 static void 6517 solve_constraints (void) 6518 { 6519 struct scc_info *si; 6520 6521 if (dump_file) 6522 fprintf (dump_file, 6523 "\nCollapsing static cycles and doing variable " 6524 "substitution\n"); 6525 6526 init_graph (VEC_length (varinfo_t, varmap) * 2); 6527 6528 if (dump_file) 6529 fprintf (dump_file, "Building predecessor graph\n"); 6530 build_pred_graph (); 6531 6532 if (dump_file) 6533 fprintf (dump_file, "Detecting pointer and location " 6534 "equivalences\n"); 6535 si = perform_var_substitution (graph); 6536 6537 if (dump_file) 6538 fprintf (dump_file, "Rewriting constraints and unifying " 6539 "variables\n"); 6540 rewrite_constraints (graph, si); 6541 6542 build_succ_graph (); 6543 6544 free_var_substitution_info (si); 6545 6546 /* Attach complex constraints to graph nodes. */ 6547 move_complex_constraints (graph); 6548 6549 if (dump_file) 6550 fprintf (dump_file, "Uniting pointer but not location equivalent " 6551 "variables\n"); 6552 unite_pointer_equivalences (graph); 6553 6554 if (dump_file) 6555 fprintf (dump_file, "Finding indirect cycles\n"); 6556 find_indirect_cycles (graph); 6557 6558 /* Implicit nodes and predecessors are no longer necessary at this 6559 point. */ 6560 remove_preds_and_fake_succs (graph); 6561 6562 if (dump_file && (dump_flags & TDF_GRAPH)) 6563 { 6564 fprintf (dump_file, "\n\n// The constraint graph before solve-graph " 6565 "in dot format:\n"); 6566 dump_constraint_graph (dump_file); 6567 fprintf (dump_file, "\n\n"); 6568 } 6569 6570 if (dump_file) 6571 fprintf (dump_file, "Solving graph\n"); 6572 6573 solve_graph (graph); 6574 6575 if (dump_file && (dump_flags & TDF_GRAPH)) 6576 { 6577 fprintf (dump_file, "\n\n// The constraint graph after solve-graph " 6578 "in dot format:\n"); 6579 dump_constraint_graph (dump_file); 6580 fprintf (dump_file, "\n\n"); 6581 } 6582 6583 if (dump_file) 6584 dump_sa_points_to_info (dump_file); 6585 } 6586 6587 /* Create points-to sets for the current function. See the comments 6588 at the start of the file for an algorithmic overview. */ 6589 6590 static void 6591 compute_points_to_sets (void) 6592 { 6593 basic_block bb; 6594 unsigned i; 6595 varinfo_t vi; 6596 6597 timevar_push (TV_TREE_PTA); 6598 6599 init_alias_vars (); 6600 6601 intra_create_variable_infos (); 6602 6603 /* Now walk all statements and build the constraint set. */ 6604 FOR_EACH_BB (bb) 6605 { 6606 gimple_stmt_iterator gsi; 6607 6608 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) 6609 { 6610 gimple phi = gsi_stmt (gsi); 6611 6612 if (is_gimple_reg (gimple_phi_result (phi))) 6613 find_func_aliases (phi); 6614 } 6615 6616 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) 6617 { 6618 gimple stmt = gsi_stmt (gsi); 6619 6620 find_func_aliases (stmt); 6621 } 6622 } 6623 6624 if (dump_file) 6625 { 6626 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n"); 6627 dump_constraints (dump_file, 0); 6628 } 6629 6630 /* From the constraints compute the points-to sets. */ 6631 solve_constraints (); 6632 6633 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */ 6634 find_what_var_points_to (get_varinfo (escaped_id), 6635 &cfun->gimple_df->escaped); 6636 6637 /* Make sure the ESCAPED solution (which is used as placeholder in 6638 other solutions) does not reference itself. This simplifies 6639 points-to solution queries. */ 6640 cfun->gimple_df->escaped.escaped = 0; 6641 6642 /* Mark escaped HEAP variables as global. */ 6643 FOR_EACH_VEC_ELT (varinfo_t, varmap, i, vi) 6644 if (vi->is_heap_var 6645 && !vi->is_global_var) 6646 DECL_EXTERNAL (vi->decl) = vi->is_global_var 6647 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl); 6648 6649 /* Compute the points-to sets for pointer SSA_NAMEs. */ 6650 for (i = 0; i < num_ssa_names; ++i) 6651 { 6652 tree ptr = ssa_name (i); 6653 if (ptr 6654 && POINTER_TYPE_P (TREE_TYPE (ptr))) 6655 find_what_p_points_to (ptr); 6656 } 6657 6658 /* Compute the call-used/clobbered sets. */ 6659 FOR_EACH_BB (bb) 6660 { 6661 gimple_stmt_iterator gsi; 6662 6663 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) 6664 { 6665 gimple stmt = gsi_stmt (gsi); 6666 struct pt_solution *pt; 6667 if (!is_gimple_call (stmt)) 6668 continue; 6669 6670 pt = gimple_call_use_set (stmt); 6671 if (gimple_call_flags (stmt) & ECF_CONST) 6672 memset (pt, 0, sizeof (struct pt_solution)); 6673 else if ((vi = lookup_call_use_vi (stmt)) != NULL) 6674 { 6675 find_what_var_points_to (vi, pt); 6676 /* Escaped (and thus nonlocal) variables are always 6677 implicitly used by calls. */ 6678 /* ??? ESCAPED can be empty even though NONLOCAL 6679 always escaped. */ 6680 pt->nonlocal = 1; 6681 pt->escaped = 1; 6682 } 6683 else 6684 { 6685 /* If there is nothing special about this call then 6686 we have made everything that is used also escape. */ 6687 *pt = cfun->gimple_df->escaped; 6688 pt->nonlocal = 1; 6689 } 6690 6691 pt = gimple_call_clobber_set (stmt); 6692 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS)) 6693 memset (pt, 0, sizeof (struct pt_solution)); 6694 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL) 6695 { 6696 find_what_var_points_to (vi, pt); 6697 /* Escaped (and thus nonlocal) variables are always 6698 implicitly clobbered by calls. */ 6699 /* ??? ESCAPED can be empty even though NONLOCAL 6700 always escaped. */ 6701 pt->nonlocal = 1; 6702 pt->escaped = 1; 6703 } 6704 else 6705 { 6706 /* If there is nothing special about this call then 6707 we have made everything that is used also escape. */ 6708 *pt = cfun->gimple_df->escaped; 6709 pt->nonlocal = 1; 6710 } 6711 } 6712 } 6713 6714 timevar_pop (TV_TREE_PTA); 6715 } 6716 6717 6718 /* Delete created points-to sets. */ 6719 6720 static void 6721 delete_points_to_sets (void) 6722 { 6723 unsigned int i; 6724 6725 htab_delete (shared_bitmap_table); 6726 if (dump_file && (dump_flags & TDF_STATS)) 6727 fprintf (dump_file, "Points to sets created:%d\n", 6728 stats.points_to_sets_created); 6729 6730 pointer_map_destroy (vi_for_tree); 6731 pointer_map_destroy (call_stmt_vars); 6732 bitmap_obstack_release (&pta_obstack); 6733 VEC_free (constraint_t, heap, constraints); 6734 6735 for (i = 0; i < graph->size; i++) 6736 VEC_free (constraint_t, heap, graph->complex[i]); 6737 free (graph->complex); 6738 6739 free (graph->rep); 6740 free (graph->succs); 6741 free (graph->pe); 6742 free (graph->pe_rep); 6743 free (graph->indirect_cycles); 6744 free (graph); 6745 6746 VEC_free (varinfo_t, heap, varmap); 6747 free_alloc_pool (variable_info_pool); 6748 free_alloc_pool (constraint_pool); 6749 6750 obstack_free (&fake_var_decl_obstack, NULL); 6751 } 6752 6753 6754 /* Compute points-to information for every SSA_NAME pointer in the 6755 current function and compute the transitive closure of escaped 6756 variables to re-initialize the call-clobber states of local variables. */ 6757 6758 unsigned int 6759 compute_may_aliases (void) 6760 { 6761 if (cfun->gimple_df->ipa_pta) 6762 { 6763 if (dump_file) 6764 { 6765 fprintf (dump_file, "\nNot re-computing points-to information " 6766 "because IPA points-to information is available.\n\n"); 6767 6768 /* But still dump what we have remaining it. */ 6769 dump_alias_info (dump_file); 6770 6771 if (dump_flags & TDF_DETAILS) 6772 dump_referenced_vars (dump_file); 6773 } 6774 6775 return 0; 6776 } 6777 6778 /* For each pointer P_i, determine the sets of variables that P_i may 6779 point-to. Compute the reachability set of escaped and call-used 6780 variables. */ 6781 compute_points_to_sets (); 6782 6783 /* Debugging dumps. */ 6784 if (dump_file) 6785 { 6786 dump_alias_info (dump_file); 6787 6788 if (dump_flags & TDF_DETAILS) 6789 dump_referenced_vars (dump_file); 6790 } 6791 6792 /* Deallocate memory used by aliasing data structures and the internal 6793 points-to solution. */ 6794 delete_points_to_sets (); 6795 6796 gcc_assert (!need_ssa_update_p (cfun)); 6797 6798 return 0; 6799 } 6800 6801 static bool 6802 gate_tree_pta (void) 6803 { 6804 return flag_tree_pta; 6805 } 6806 6807 /* A dummy pass to cause points-to information to be computed via 6808 TODO_rebuild_alias. */ 6809 6810 struct gimple_opt_pass pass_build_alias = 6811 { 6812 { 6813 GIMPLE_PASS, 6814 "alias", /* name */ 6815 gate_tree_pta, /* gate */ 6816 NULL, /* execute */ 6817 NULL, /* sub */ 6818 NULL, /* next */ 6819 0, /* static_pass_number */ 6820 TV_NONE, /* tv_id */ 6821 PROP_cfg | PROP_ssa, /* properties_required */ 6822 0, /* properties_provided */ 6823 0, /* properties_destroyed */ 6824 0, /* todo_flags_start */ 6825 TODO_rebuild_alias /* todo_flags_finish */ 6826 } 6827 }; 6828 6829 /* A dummy pass to cause points-to information to be computed via 6830 TODO_rebuild_alias. */ 6831 6832 struct gimple_opt_pass pass_build_ealias = 6833 { 6834 { 6835 GIMPLE_PASS, 6836 "ealias", /* name */ 6837 gate_tree_pta, /* gate */ 6838 NULL, /* execute */ 6839 NULL, /* sub */ 6840 NULL, /* next */ 6841 0, /* static_pass_number */ 6842 TV_NONE, /* tv_id */ 6843 PROP_cfg | PROP_ssa, /* properties_required */ 6844 0, /* properties_provided */ 6845 0, /* properties_destroyed */ 6846 0, /* todo_flags_start */ 6847 TODO_rebuild_alias /* todo_flags_finish */ 6848 } 6849 }; 6850 6851 6852 /* Return true if we should execute IPA PTA. */ 6853 static bool 6854 gate_ipa_pta (void) 6855 { 6856 return (optimize 6857 && flag_ipa_pta 6858 /* Don't bother doing anything if the program has errors. */ 6859 && !seen_error ()); 6860 } 6861 6862 /* IPA PTA solutions for ESCAPED. */ 6863 struct pt_solution ipa_escaped_pt 6864 = { true, false, false, false, false, false, NULL }; 6865 6866 /* Associate node with varinfo DATA. Worker for 6867 cgraph_for_node_and_aliases. */ 6868 static bool 6869 associate_varinfo_to_alias (struct cgraph_node *node, void *data) 6870 { 6871 if (node->alias || node->thunk.thunk_p) 6872 insert_vi_for_tree (node->decl, (varinfo_t)data); 6873 return false; 6874 } 6875 6876 /* Execute the driver for IPA PTA. */ 6877 static unsigned int 6878 ipa_pta_execute (void) 6879 { 6880 struct cgraph_node *node; 6881 struct varpool_node *var; 6882 int from; 6883 6884 in_ipa_mode = 1; 6885 6886 init_alias_vars (); 6887 6888 if (dump_file && (dump_flags & TDF_DETAILS)) 6889 { 6890 dump_cgraph (dump_file); 6891 fprintf (dump_file, "\n"); 6892 } 6893 6894 /* Build the constraints. */ 6895 for (node = cgraph_nodes; node; node = node->next) 6896 { 6897 varinfo_t vi; 6898 /* Nodes without a body are not interesting. Especially do not 6899 visit clones at this point for now - we get duplicate decls 6900 there for inline clones at least. */ 6901 if (!cgraph_function_with_gimple_body_p (node)) 6902 continue; 6903 6904 gcc_assert (!node->clone_of); 6905 6906 vi = create_function_info_for (node->decl, 6907 alias_get_name (node->decl)); 6908 cgraph_for_node_and_aliases (node, associate_varinfo_to_alias, vi, true); 6909 } 6910 6911 /* Create constraints for global variables and their initializers. */ 6912 for (var = varpool_nodes; var; var = var->next) 6913 { 6914 if (var->alias) 6915 continue; 6916 6917 get_vi_for_tree (var->decl); 6918 } 6919 6920 if (dump_file) 6921 { 6922 fprintf (dump_file, 6923 "Generating constraints for global initializers\n\n"); 6924 dump_constraints (dump_file, 0); 6925 fprintf (dump_file, "\n"); 6926 } 6927 from = VEC_length (constraint_t, constraints); 6928 6929 for (node = cgraph_nodes; node; node = node->next) 6930 { 6931 struct function *func; 6932 basic_block bb; 6933 tree old_func_decl; 6934 6935 /* Nodes without a body are not interesting. */ 6936 if (!cgraph_function_with_gimple_body_p (node)) 6937 continue; 6938 6939 if (dump_file) 6940 { 6941 fprintf (dump_file, 6942 "Generating constraints for %s", cgraph_node_name (node)); 6943 if (DECL_ASSEMBLER_NAME_SET_P (node->decl)) 6944 fprintf (dump_file, " (%s)", 6945 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl))); 6946 fprintf (dump_file, "\n"); 6947 } 6948 6949 func = DECL_STRUCT_FUNCTION (node->decl); 6950 old_func_decl = current_function_decl; 6951 push_cfun (func); 6952 current_function_decl = node->decl; 6953 6954 /* For externally visible or attribute used annotated functions use 6955 local constraints for their arguments. 6956 For local functions we see all callers and thus do not need initial 6957 constraints for parameters. */ 6958 if (node->reachable_from_other_partition 6959 || node->local.externally_visible 6960 || node->needed) 6961 { 6962 intra_create_variable_infos (); 6963 6964 /* We also need to make function return values escape. Nothing 6965 escapes by returning from main though. */ 6966 if (!MAIN_NAME_P (DECL_NAME (node->decl))) 6967 { 6968 varinfo_t fi, rvi; 6969 fi = lookup_vi_for_tree (node->decl); 6970 rvi = first_vi_for_offset (fi, fi_result); 6971 if (rvi && rvi->offset == fi_result) 6972 { 6973 struct constraint_expr includes; 6974 struct constraint_expr var; 6975 includes.var = escaped_id; 6976 includes.offset = 0; 6977 includes.type = SCALAR; 6978 var.var = rvi->id; 6979 var.offset = 0; 6980 var.type = SCALAR; 6981 process_constraint (new_constraint (includes, var)); 6982 } 6983 } 6984 } 6985 6986 /* Build constriants for the function body. */ 6987 FOR_EACH_BB_FN (bb, func) 6988 { 6989 gimple_stmt_iterator gsi; 6990 6991 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); 6992 gsi_next (&gsi)) 6993 { 6994 gimple phi = gsi_stmt (gsi); 6995 6996 if (is_gimple_reg (gimple_phi_result (phi))) 6997 find_func_aliases (phi); 6998 } 6999 7000 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) 7001 { 7002 gimple stmt = gsi_stmt (gsi); 7003 7004 find_func_aliases (stmt); 7005 find_func_clobbers (stmt); 7006 } 7007 } 7008 7009 current_function_decl = old_func_decl; 7010 pop_cfun (); 7011 7012 if (dump_file) 7013 { 7014 fprintf (dump_file, "\n"); 7015 dump_constraints (dump_file, from); 7016 fprintf (dump_file, "\n"); 7017 } 7018 from = VEC_length (constraint_t, constraints); 7019 } 7020 7021 /* From the constraints compute the points-to sets. */ 7022 solve_constraints (); 7023 7024 /* Compute the global points-to sets for ESCAPED. 7025 ??? Note that the computed escape set is not correct 7026 for the whole unit as we fail to consider graph edges to 7027 externally visible functions. */ 7028 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt); 7029 7030 /* Make sure the ESCAPED solution (which is used as placeholder in 7031 other solutions) does not reference itself. This simplifies 7032 points-to solution queries. */ 7033 ipa_escaped_pt.ipa_escaped = 0; 7034 7035 /* Assign the points-to sets to the SSA names in the unit. */ 7036 for (node = cgraph_nodes; node; node = node->next) 7037 { 7038 tree ptr; 7039 struct function *fn; 7040 unsigned i; 7041 varinfo_t fi; 7042 basic_block bb; 7043 struct pt_solution uses, clobbers; 7044 struct cgraph_edge *e; 7045 7046 /* Nodes without a body are not interesting. */ 7047 if (!cgraph_function_with_gimple_body_p (node)) 7048 continue; 7049 7050 fn = DECL_STRUCT_FUNCTION (node->decl); 7051 7052 /* Compute the points-to sets for pointer SSA_NAMEs. */ 7053 FOR_EACH_VEC_ELT (tree, fn->gimple_df->ssa_names, i, ptr) 7054 { 7055 if (ptr 7056 && POINTER_TYPE_P (TREE_TYPE (ptr))) 7057 find_what_p_points_to (ptr); 7058 } 7059 7060 /* Compute the call-use and call-clobber sets for all direct calls. */ 7061 fi = lookup_vi_for_tree (node->decl); 7062 gcc_assert (fi->is_fn_info); 7063 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers), 7064 &clobbers); 7065 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses); 7066 for (e = node->callers; e; e = e->next_caller) 7067 { 7068 if (!e->call_stmt) 7069 continue; 7070 7071 *gimple_call_clobber_set (e->call_stmt) = clobbers; 7072 *gimple_call_use_set (e->call_stmt) = uses; 7073 } 7074 7075 /* Compute the call-use and call-clobber sets for indirect calls 7076 and calls to external functions. */ 7077 FOR_EACH_BB_FN (bb, fn) 7078 { 7079 gimple_stmt_iterator gsi; 7080 7081 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) 7082 { 7083 gimple stmt = gsi_stmt (gsi); 7084 struct pt_solution *pt; 7085 varinfo_t vi; 7086 tree decl; 7087 7088 if (!is_gimple_call (stmt)) 7089 continue; 7090 7091 /* Handle direct calls to external functions. */ 7092 decl = gimple_call_fndecl (stmt); 7093 if (decl 7094 && (!(fi = lookup_vi_for_tree (decl)) 7095 || !fi->is_fn_info)) 7096 { 7097 pt = gimple_call_use_set (stmt); 7098 if (gimple_call_flags (stmt) & ECF_CONST) 7099 memset (pt, 0, sizeof (struct pt_solution)); 7100 else if ((vi = lookup_call_use_vi (stmt)) != NULL) 7101 { 7102 find_what_var_points_to (vi, pt); 7103 /* Escaped (and thus nonlocal) variables are always 7104 implicitly used by calls. */ 7105 /* ??? ESCAPED can be empty even though NONLOCAL 7106 always escaped. */ 7107 pt->nonlocal = 1; 7108 pt->ipa_escaped = 1; 7109 } 7110 else 7111 { 7112 /* If there is nothing special about this call then 7113 we have made everything that is used also escape. */ 7114 *pt = ipa_escaped_pt; 7115 pt->nonlocal = 1; 7116 } 7117 7118 pt = gimple_call_clobber_set (stmt); 7119 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS)) 7120 memset (pt, 0, sizeof (struct pt_solution)); 7121 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL) 7122 { 7123 find_what_var_points_to (vi, pt); 7124 /* Escaped (and thus nonlocal) variables are always 7125 implicitly clobbered by calls. */ 7126 /* ??? ESCAPED can be empty even though NONLOCAL 7127 always escaped. */ 7128 pt->nonlocal = 1; 7129 pt->ipa_escaped = 1; 7130 } 7131 else 7132 { 7133 /* If there is nothing special about this call then 7134 we have made everything that is used also escape. */ 7135 *pt = ipa_escaped_pt; 7136 pt->nonlocal = 1; 7137 } 7138 } 7139 7140 /* Handle indirect calls. */ 7141 if (!decl 7142 && (fi = get_fi_for_callee (stmt))) 7143 { 7144 /* We need to accumulate all clobbers/uses of all possible 7145 callees. */ 7146 fi = get_varinfo (find (fi->id)); 7147 /* If we cannot constrain the set of functions we'll end up 7148 calling we end up using/clobbering everything. */ 7149 if (bitmap_bit_p (fi->solution, anything_id) 7150 || bitmap_bit_p (fi->solution, nonlocal_id) 7151 || bitmap_bit_p (fi->solution, escaped_id)) 7152 { 7153 pt_solution_reset (gimple_call_clobber_set (stmt)); 7154 pt_solution_reset (gimple_call_use_set (stmt)); 7155 } 7156 else 7157 { 7158 bitmap_iterator bi; 7159 unsigned i; 7160 struct pt_solution *uses, *clobbers; 7161 7162 uses = gimple_call_use_set (stmt); 7163 clobbers = gimple_call_clobber_set (stmt); 7164 memset (uses, 0, sizeof (struct pt_solution)); 7165 memset (clobbers, 0, sizeof (struct pt_solution)); 7166 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi) 7167 { 7168 struct pt_solution sol; 7169 7170 vi = get_varinfo (i); 7171 if (!vi->is_fn_info) 7172 { 7173 /* ??? We could be more precise here? */ 7174 uses->nonlocal = 1; 7175 uses->ipa_escaped = 1; 7176 clobbers->nonlocal = 1; 7177 clobbers->ipa_escaped = 1; 7178 continue; 7179 } 7180 7181 if (!uses->anything) 7182 { 7183 find_what_var_points_to 7184 (first_vi_for_offset (vi, fi_uses), &sol); 7185 pt_solution_ior_into (uses, &sol); 7186 } 7187 if (!clobbers->anything) 7188 { 7189 find_what_var_points_to 7190 (first_vi_for_offset (vi, fi_clobbers), &sol); 7191 pt_solution_ior_into (clobbers, &sol); 7192 } 7193 } 7194 } 7195 } 7196 } 7197 } 7198 7199 fn->gimple_df->ipa_pta = true; 7200 } 7201 7202 delete_points_to_sets (); 7203 7204 in_ipa_mode = 0; 7205 7206 return 0; 7207 } 7208 7209 struct simple_ipa_opt_pass pass_ipa_pta = 7210 { 7211 { 7212 SIMPLE_IPA_PASS, 7213 "pta", /* name */ 7214 gate_ipa_pta, /* gate */ 7215 ipa_pta_execute, /* execute */ 7216 NULL, /* sub */ 7217 NULL, /* next */ 7218 0, /* static_pass_number */ 7219 TV_IPA_PTA, /* tv_id */ 7220 0, /* properties_required */ 7221 0, /* properties_provided */ 7222 0, /* properties_destroyed */ 7223 0, /* todo_flags_start */ 7224 TODO_update_ssa /* todo_flags_finish */ 7225 } 7226 }; 7227