1 /* Miscellaneous SSA utility functions.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
31 #include "langhooks.h"
32 #include "hard-reg-set.h"
33 #include "basic-block.h"
37 #include "diagnostic.h"
39 #include "pointer-set.h"
40 #include "tree-flow.h"
42 #include "tree-inline.h"
46 #include "tree-dump.h"
47 #include "tree-pass.h"
50 /* Pointer map of variable mappings, keyed by edge. */
51 static struct pointer_map_t *edge_var_maps;
54 /* Add a mapping with PHI RESULT and PHI DEF associated with edge E. */
57 redirect_edge_var_map_add (edge e, tree result, tree def, source_location locus)
60 edge_var_map_vector old_head, head;
61 edge_var_map new_node;
63 if (edge_var_maps == NULL)
64 edge_var_maps = pointer_map_create ();
66 slot = pointer_map_insert (edge_var_maps, e);
67 old_head = head = (edge_var_map_vector) *slot;
70 head = VEC_alloc (edge_var_map, heap, 5);
74 new_node.result = result;
75 new_node.locus = locus;
77 VEC_safe_push (edge_var_map, heap, head, &new_node);
80 /* The push did some reallocation. Update the pointer map. */
86 /* Clear the var mappings in edge E. */
89 redirect_edge_var_map_clear (edge e)
92 edge_var_map_vector head;
97 slot = pointer_map_contains (edge_var_maps, e);
101 head = (edge_var_map_vector) *slot;
102 VEC_free (edge_var_map, heap, head);
108 /* Duplicate the redirected var mappings in OLDE in NEWE.
110 Since we can't remove a mapping, let's just duplicate it. This assumes a
111 pointer_map can have multiple edges mapping to the same var_map (many to
112 one mapping), since we don't remove the previous mappings. */
115 redirect_edge_var_map_dup (edge newe, edge olde)
117 void **new_slot, **old_slot;
118 edge_var_map_vector head;
123 new_slot = pointer_map_insert (edge_var_maps, newe);
124 old_slot = pointer_map_contains (edge_var_maps, olde);
127 head = (edge_var_map_vector) *old_slot;
130 *new_slot = VEC_copy (edge_var_map, heap, head);
132 *new_slot = VEC_alloc (edge_var_map, heap, 5);
136 /* Return the variable mappings for a given edge. If there is none, return
140 redirect_edge_var_map_vector (edge e)
144 /* Hey, what kind of idiot would... you'd be surprised. */
148 slot = pointer_map_contains (edge_var_maps, e);
152 return (edge_var_map_vector) *slot;
155 /* Used by redirect_edge_var_map_destroy to free all memory. */
158 free_var_map_entry (const void *key ATTRIBUTE_UNUSED,
160 void *data ATTRIBUTE_UNUSED)
162 edge_var_map_vector head = (edge_var_map_vector) *value;
163 VEC_free (edge_var_map, heap, head);
167 /* Clear the edge variable mappings. */
170 redirect_edge_var_map_destroy (void)
174 pointer_map_traverse (edge_var_maps, free_var_map_entry, NULL);
175 pointer_map_destroy (edge_var_maps);
176 edge_var_maps = NULL;
181 /* Remove the corresponding arguments from the PHI nodes in E's
182 destination block and redirect it to DEST. Return redirected edge.
183 The list of removed arguments is stored in a vector accessed
184 through edge_var_maps. */
187 ssa_redirect_edge (edge e, basic_block dest)
189 gimple_stmt_iterator gsi;
192 redirect_edge_var_map_clear (e);
194 /* Remove the appropriate PHI arguments in E's destination block. */
195 for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
198 source_location locus ;
200 phi = gsi_stmt (gsi);
201 def = gimple_phi_arg_def (phi, e->dest_idx);
202 locus = gimple_phi_arg_location (phi, e->dest_idx);
204 if (def == NULL_TREE)
207 redirect_edge_var_map_add (e, gimple_phi_result (phi), def, locus);
210 e = redirect_edge_succ_nodup (e, dest);
216 /* Add PHI arguments queued in PENDING_STMT list on edge E to edge
220 flush_pending_stmts (edge e)
223 edge_var_map_vector v;
226 gimple_stmt_iterator gsi;
228 v = redirect_edge_var_map_vector (e);
232 for (gsi = gsi_start_phis (e->dest), i = 0;
233 !gsi_end_p (gsi) && VEC_iterate (edge_var_map, v, i, vm);
234 gsi_next (&gsi), i++)
238 phi = gsi_stmt (gsi);
239 def = redirect_edge_var_map_def (vm);
240 add_phi_arg (phi, def, e, redirect_edge_var_map_location (vm));
243 redirect_edge_var_map_clear (e);
246 /* Given a tree for an expression for which we might want to emit
247 locations or values in debug information (generally a variable, but
248 we might deal with other kinds of trees in the future), return the
249 tree that should be used as the variable of a DEBUG_BIND STMT or
250 VAR_LOCATION INSN or NOTE. Return NULL if VAR is not to be tracked. */
253 target_for_debug_bind (tree var)
255 if (!MAY_HAVE_DEBUG_STMTS)
258 if (TREE_CODE (var) != VAR_DECL
259 && TREE_CODE (var) != PARM_DECL)
262 if (DECL_HAS_VALUE_EXPR_P (var))
263 return target_for_debug_bind (DECL_VALUE_EXPR (var));
265 if (DECL_IGNORED_P (var))
268 if (!is_gimple_reg (var))
274 /* Called via walk_tree, look for SSA_NAMEs that have already been
278 find_released_ssa_name (tree *tp, int *walk_subtrees, void *data_)
280 struct walk_stmt_info *wi = (struct walk_stmt_info *) data_;
285 if (TREE_CODE (*tp) == SSA_NAME)
287 if (SSA_NAME_IN_FREE_LIST (*tp))
292 else if (IS_TYPE_OR_DECL_P (*tp))
298 /* Insert a DEBUG BIND stmt before the DEF of VAR if VAR is referenced
299 by other DEBUG stmts, and replace uses of the DEF with the
300 newly-created debug temp. */
303 insert_debug_temp_for_var_def (gimple_stmt_iterator *gsi, tree var)
305 imm_use_iterator imm_iter;
308 gimple def_stmt = NULL;
312 if (!MAY_HAVE_DEBUG_STMTS)
315 /* First of all, check whether there are debug stmts that reference
316 this variable and, if there are, decide whether we should use a
318 FOR_EACH_IMM_USE_FAST (use_p, imm_iter, var)
320 stmt = USE_STMT (use_p);
322 if (!gimple_debug_bind_p (stmt))
328 if (gimple_debug_bind_get_value (stmt) != var)
330 /* Count this as an additional use, so as to make sure we
331 use a temp unless VAR's definition has a SINGLE_RHS that
342 def_stmt = gsi_stmt (*gsi);
344 def_stmt = SSA_NAME_DEF_STMT (var);
346 /* If we didn't get an insertion point, and the stmt has already
347 been removed, we won't be able to insert the debug bind stmt, so
348 we'll have to drop debug information. */
349 if (is_gimple_assign (def_stmt))
351 bool no_value = false;
353 if (!dom_info_available_p (CDI_DOMINATORS))
355 struct walk_stmt_info wi;
357 memset (&wi, 0, sizeof (wi));
359 /* When removing blocks without following reverse dominance
360 order, we may sometimes encounter SSA_NAMEs that have
361 already been released, referenced in other SSA_DEFs that
362 we're about to release. Consider:
371 If we deleted BB X first, propagating the value of w_2
372 won't do us any good. It's too late to recover their
373 original definition of v_1: when it was deleted, it was
374 only referenced in other DEFs, it couldn't possibly know
375 it should have been retained, and propagating every
376 single DEF just in case it might have to be propagated
377 into a DEBUG STMT would probably be too wasteful.
379 When dominator information is not readily available, we
380 check for and accept some loss of debug information. But
381 if it is available, there's no excuse for us to remove
382 blocks in the wrong order, so we don't even check for
383 dead SSA NAMEs. SSA verification shall catch any
385 if ((!gsi && !gimple_bb (def_stmt))
386 || !walk_gimple_op (def_stmt, find_released_ssa_name,
392 value = gimple_assign_rhs_to_tree (def_stmt);
397 /* If there's a single use of VAR, and VAR is the entire debug
398 expression (usecount would have been incremented again
399 otherwise), and the definition involves only constants and
400 SSA names, then we can propagate VALUE into this single use,
403 We can also avoid using a temp if VALUE can be shared and
404 propagated into all uses, without generating expressions that
405 wouldn't be valid gimple RHSs.
407 Other cases that would require unsharing or non-gimple RHSs
408 are deferred to a debug temp, although we could avoid temps
409 at the expense of duplication of expressions. */
411 if (CONSTANT_CLASS_P (value)
413 && (!gimple_assign_single_p (def_stmt)
414 || is_gimple_min_invariant (value)))
415 || is_gimple_reg (value))
416 value = unshare_expr (value);
420 tree vexpr = make_node (DEBUG_EXPR_DECL);
422 def_temp = gimple_build_debug_bind (vexpr,
423 unshare_expr (value),
426 DECL_ARTIFICIAL (vexpr) = 1;
427 TREE_TYPE (vexpr) = TREE_TYPE (value);
429 DECL_MODE (vexpr) = DECL_MODE (value);
431 DECL_MODE (vexpr) = TYPE_MODE (TREE_TYPE (value));
434 gsi_insert_before (gsi, def_temp, GSI_SAME_STMT);
437 gimple_stmt_iterator ngsi = gsi_for_stmt (def_stmt);
438 gsi_insert_before (&ngsi, def_temp, GSI_SAME_STMT);
445 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, var)
447 if (!gimple_debug_bind_p (stmt))
451 FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
452 /* unshare_expr is not needed here. vexpr is either a
453 SINGLE_RHS, that can be safely shared, some other RHS
454 that was unshared when we found it had a single debug
455 use, or a DEBUG_EXPR_DECL, that can be safely
457 SET_USE (use_p, value);
459 gimple_debug_bind_reset_value (stmt);
466 /* Insert a DEBUG BIND stmt before STMT for each DEF referenced by
467 other DEBUG stmts, and replace uses of the DEF with the
468 newly-created debug temp. */
471 insert_debug_temps_for_defs (gimple_stmt_iterator *gsi)
477 if (!MAY_HAVE_DEBUG_STMTS)
480 stmt = gsi_stmt (*gsi);
482 FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, op_iter, SSA_OP_DEF)
484 tree var = DEF_FROM_PTR (def_p);
486 if (TREE_CODE (var) != SSA_NAME)
489 insert_debug_temp_for_var_def (gsi, var);
493 /* Delete SSA DEFs for SSA versions in the TOREMOVE bitmap, removing
494 dominated stmts before their dominators, so that release_ssa_defs
495 stands a chance of propagating DEFs into debug bind stmts. */
498 release_defs_bitset (bitmap toremove)
503 /* Performing a topological sort is probably overkill, this will
504 most likely run in slightly superlinear time, rather than the
505 pathological quadratic worst case. */
506 while (!bitmap_empty_p (toremove))
507 EXECUTE_IF_SET_IN_BITMAP (toremove, 0, j, bi)
509 bool remove_now = true;
510 tree var = ssa_name (j);
512 imm_use_iterator uit;
514 FOR_EACH_IMM_USE_STMT (stmt, uit, var)
519 /* We can't propagate PHI nodes into debug stmts. */
520 if (gimple_code (stmt) == GIMPLE_PHI
521 || is_gimple_debug (stmt))
524 /* If we find another definition to remove that uses
525 the one we're looking at, defer the removal of this
526 one, so that it can be propagated into debug stmts
527 after the other is. */
528 FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, dit, SSA_OP_DEF)
530 tree odef = DEF_FROM_PTR (def_p);
532 if (bitmap_bit_p (toremove, SSA_NAME_VERSION (odef)))
540 BREAK_FROM_IMM_USE_STMT (uit);
545 gimple def = SSA_NAME_DEF_STMT (var);
546 gimple_stmt_iterator gsi = gsi_for_stmt (def);
548 if (gimple_code (def) == GIMPLE_PHI)
549 remove_phi_node (&gsi, true);
552 gsi_remove (&gsi, true);
556 bitmap_clear_bit (toremove, j);
561 /* Return true if SSA_NAME is malformed and mark it visited.
563 IS_VIRTUAL is true if this SSA_NAME was found inside a virtual
567 verify_ssa_name (tree ssa_name, bool is_virtual)
569 if (TREE_CODE (ssa_name) != SSA_NAME)
571 error ("expected an SSA_NAME object");
575 if (TREE_TYPE (ssa_name) != TREE_TYPE (SSA_NAME_VAR (ssa_name)))
577 error ("type mismatch between an SSA_NAME and its symbol");
581 if (SSA_NAME_IN_FREE_LIST (ssa_name))
583 error ("found an SSA_NAME that had been released into the free pool");
587 if (is_virtual && is_gimple_reg (ssa_name))
589 error ("found a virtual definition for a GIMPLE register");
593 if (is_virtual && SSA_NAME_VAR (ssa_name) != gimple_vop (cfun))
595 error ("virtual SSA name for non-VOP decl");
599 if (!is_virtual && !is_gimple_reg (ssa_name))
601 error ("found a real definition for a non-register");
605 if (SSA_NAME_IS_DEFAULT_DEF (ssa_name)
606 && !gimple_nop_p (SSA_NAME_DEF_STMT (ssa_name)))
608 error ("found a default name with a non-empty defining statement");
616 /* Return true if the definition of SSA_NAME at block BB is malformed.
618 STMT is the statement where SSA_NAME is created.
620 DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME
621 version numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set,
622 it means that the block in that array slot contains the
623 definition of SSA_NAME.
625 IS_VIRTUAL is true if SSA_NAME is created by a VDEF. */
628 verify_def (basic_block bb, basic_block *definition_block, tree ssa_name,
629 gimple stmt, bool is_virtual)
631 if (verify_ssa_name (ssa_name, is_virtual))
634 if (definition_block[SSA_NAME_VERSION (ssa_name)])
636 error ("SSA_NAME created in two different blocks %i and %i",
637 definition_block[SSA_NAME_VERSION (ssa_name)]->index, bb->index);
641 definition_block[SSA_NAME_VERSION (ssa_name)] = bb;
643 if (SSA_NAME_DEF_STMT (ssa_name) != stmt)
645 error ("SSA_NAME_DEF_STMT is wrong");
646 fprintf (stderr, "Expected definition statement:\n");
647 print_gimple_stmt (stderr, SSA_NAME_DEF_STMT (ssa_name), 4, TDF_VOPS);
648 fprintf (stderr, "\nActual definition statement:\n");
649 print_gimple_stmt (stderr, stmt, 4, TDF_VOPS);
656 fprintf (stderr, "while verifying SSA_NAME ");
657 print_generic_expr (stderr, ssa_name, 0);
658 fprintf (stderr, " in statement\n");
659 print_gimple_stmt (stderr, stmt, 4, TDF_VOPS);
665 /* Return true if the use of SSA_NAME at statement STMT in block BB is
668 DEF_BB is the block where SSA_NAME was found to be created.
670 IDOM contains immediate dominator information for the flowgraph.
672 CHECK_ABNORMAL is true if the caller wants to check whether this use
673 is flowing through an abnormal edge (only used when checking PHI
676 If NAMES_DEFINED_IN_BB is not NULL, it contains a bitmap of ssa names
677 that are defined before STMT in basic block BB. */
680 verify_use (basic_block bb, basic_block def_bb, use_operand_p use_p,
681 gimple stmt, bool check_abnormal, bitmap names_defined_in_bb)
684 tree ssa_name = USE_FROM_PTR (use_p);
686 if (!TREE_VISITED (ssa_name))
687 if (verify_imm_links (stderr, ssa_name))
690 TREE_VISITED (ssa_name) = 1;
692 if (gimple_nop_p (SSA_NAME_DEF_STMT (ssa_name))
693 && SSA_NAME_IS_DEFAULT_DEF (ssa_name))
694 ; /* Default definitions have empty statements. Nothing to do. */
697 error ("missing definition");
700 else if (bb != def_bb
701 && !dominated_by_p (CDI_DOMINATORS, bb, def_bb))
703 error ("definition in block %i does not dominate use in block %i",
704 def_bb->index, bb->index);
707 else if (bb == def_bb
708 && names_defined_in_bb != NULL
709 && !bitmap_bit_p (names_defined_in_bb, SSA_NAME_VERSION (ssa_name)))
711 error ("definition in block %i follows the use", def_bb->index);
716 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ssa_name))
718 error ("SSA_NAME_OCCURS_IN_ABNORMAL_PHI should be set");
722 /* Make sure the use is in an appropriate list by checking the previous
723 element to make sure it's the same. */
724 if (use_p->prev == NULL)
726 error ("no immediate_use list");
732 if (use_p->prev->use == NULL)
733 listvar = use_p->prev->loc.ssa_name;
735 listvar = USE_FROM_PTR (use_p->prev);
736 if (listvar != ssa_name)
738 error ("wrong immediate use list");
745 fprintf (stderr, "for SSA_NAME: ");
746 print_generic_expr (stderr, ssa_name, TDF_VOPS);
747 fprintf (stderr, " in statement:\n");
748 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS);
755 /* Return true if any of the arguments for PHI node PHI at block BB is
758 DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME
759 version numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set,
760 it means that the block in that array slot contains the
761 definition of SSA_NAME. */
764 verify_phi_args (gimple phi, basic_block bb, basic_block *definition_block)
768 size_t i, phi_num_args = gimple_phi_num_args (phi);
770 if (EDGE_COUNT (bb->preds) != phi_num_args)
772 error ("incoming edge count does not match number of PHI arguments");
777 for (i = 0; i < phi_num_args; i++)
779 use_operand_p op_p = gimple_phi_arg_imm_use_ptr (phi, i);
780 tree op = USE_FROM_PTR (op_p);
782 e = EDGE_PRED (bb, i);
786 error ("PHI argument is missing for edge %d->%d",
793 if (TREE_CODE (op) != SSA_NAME && !is_gimple_min_invariant (op))
795 error ("PHI argument is not SSA_NAME, or invariant");
799 if (TREE_CODE (op) == SSA_NAME)
801 err = verify_ssa_name (op, !is_gimple_reg (gimple_phi_result (phi)));
802 err |= verify_use (e->src, definition_block[SSA_NAME_VERSION (op)],
803 op_p, phi, e->flags & EDGE_ABNORMAL, NULL);
806 if (TREE_CODE (op) == ADDR_EXPR)
808 tree base = TREE_OPERAND (op, 0);
809 while (handled_component_p (base))
810 base = TREE_OPERAND (base, 0);
811 if ((TREE_CODE (base) == VAR_DECL
812 || TREE_CODE (base) == PARM_DECL
813 || TREE_CODE (base) == RESULT_DECL)
814 && !TREE_ADDRESSABLE (base))
816 error ("address taken, but ADDRESSABLE bit not set");
823 error ("wrong edge %d->%d for PHI argument",
824 e->src->index, e->dest->index);
830 fprintf (stderr, "PHI argument\n");
831 print_generic_stmt (stderr, op, TDF_VOPS);
839 fprintf (stderr, "for PHI node\n");
840 print_gimple_stmt (stderr, phi, 0, TDF_VOPS|TDF_MEMSYMS);
848 /* Verify common invariants in the SSA web.
849 TODO: verify the variable annotations. */
852 verify_ssa (bool check_modified_stmt)
856 basic_block *definition_block = XCNEWVEC (basic_block, num_ssa_names);
859 enum dom_state orig_dom_state = dom_info_state (CDI_DOMINATORS);
860 bitmap names_defined_in_bb = BITMAP_ALLOC (NULL);
862 gcc_assert (!need_ssa_update_p (cfun));
866 timevar_push (TV_TREE_SSA_VERIFY);
868 /* Keep track of SSA names present in the IL. */
869 for (i = 1; i < num_ssa_names; i++)
871 tree name = ssa_name (i);
875 TREE_VISITED (name) = 0;
877 stmt = SSA_NAME_DEF_STMT (name);
878 if (!gimple_nop_p (stmt))
880 basic_block bb = gimple_bb (stmt);
881 verify_def (bb, definition_block,
882 name, stmt, !is_gimple_reg (name));
888 calculate_dominance_info (CDI_DOMINATORS);
890 /* Now verify all the uses and make sure they agree with the definitions
891 found in the previous pass. */
897 gimple_stmt_iterator gsi;
899 /* Make sure that all edges have a clear 'aux' field. */
900 FOR_EACH_EDGE (e, ei, bb->preds)
904 error ("AUX pointer initialized for edge %d->%d", e->src->index,
910 /* Verify the arguments for every PHI node in the block. */
911 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
913 phi = gsi_stmt (gsi);
914 if (verify_phi_args (phi, bb, definition_block))
917 bitmap_set_bit (names_defined_in_bb,
918 SSA_NAME_VERSION (gimple_phi_result (phi)));
921 /* Now verify all the uses and vuses in every statement of the block. */
922 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
924 gimple stmt = gsi_stmt (gsi);
928 if (check_modified_stmt && gimple_modified_p (stmt))
930 error ("stmt (%p) marked modified after optimization pass: ",
932 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS);
936 if (is_gimple_assign (stmt)
937 && TREE_CODE (gimple_assign_lhs (stmt)) != SSA_NAME)
939 tree lhs, base_address;
941 lhs = gimple_assign_lhs (stmt);
942 base_address = get_base_address (lhs);
945 && SSA_VAR_P (base_address)
946 && !gimple_vdef (stmt)
949 error ("statement makes a memory store, but has no VDEFS");
950 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS);
954 else if (gimple_debug_bind_p (stmt)
955 && !gimple_debug_bind_has_value_p (stmt))
958 /* Verify the single virtual operand and its constraints. */
960 if (gimple_vdef (stmt))
962 if (gimple_vdef_op (stmt) == NULL_DEF_OPERAND_P)
964 error ("statement has VDEF operand not in defs list");
967 if (!gimple_vuse (stmt))
969 error ("statement has VDEF but no VUSE operand");
972 else if (SSA_NAME_VAR (gimple_vdef (stmt))
973 != SSA_NAME_VAR (gimple_vuse (stmt)))
975 error ("VDEF and VUSE do not use the same symbol");
978 has_err |= verify_ssa_name (gimple_vdef (stmt), true);
980 if (gimple_vuse (stmt))
982 if (gimple_vuse_op (stmt) == NULL_USE_OPERAND_P)
984 error ("statement has VUSE operand not in uses list");
987 has_err |= verify_ssa_name (gimple_vuse (stmt), true);
991 error ("in statement");
992 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS|TDF_MEMSYMS);
996 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE|SSA_OP_DEF)
998 if (verify_ssa_name (op, false))
1000 error ("in statement");
1001 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS|TDF_MEMSYMS);
1006 FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE|SSA_OP_VUSE)
1008 op = USE_FROM_PTR (use_p);
1009 if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)],
1010 use_p, stmt, false, names_defined_in_bb))
1014 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_ALL_DEFS)
1016 if (SSA_NAME_DEF_STMT (op) != stmt)
1018 error ("SSA_NAME_DEF_STMT is wrong");
1019 fprintf (stderr, "Expected definition statement:\n");
1020 print_gimple_stmt (stderr, stmt, 4, TDF_VOPS);
1021 fprintf (stderr, "\nActual definition statement:\n");
1022 print_gimple_stmt (stderr, SSA_NAME_DEF_STMT (op),
1026 bitmap_set_bit (names_defined_in_bb, SSA_NAME_VERSION (op));
1030 bitmap_clear (names_defined_in_bb);
1033 free (definition_block);
1035 /* Restore the dominance information to its prior known state, so
1036 that we do not perturb the compiler's subsequent behavior. */
1037 if (orig_dom_state == DOM_NONE)
1038 free_dominance_info (CDI_DOMINATORS);
1040 set_dom_info_availability (CDI_DOMINATORS, orig_dom_state);
1042 BITMAP_FREE (names_defined_in_bb);
1043 timevar_pop (TV_TREE_SSA_VERIFY);
1047 internal_error ("verify_ssa failed");
1050 /* Return true if the uid in both int tree maps are equal. */
1053 int_tree_map_eq (const void *va, const void *vb)
1055 const struct int_tree_map *a = (const struct int_tree_map *) va;
1056 const struct int_tree_map *b = (const struct int_tree_map *) vb;
1057 return (a->uid == b->uid);
1060 /* Hash a UID in a int_tree_map. */
1063 int_tree_map_hash (const void *item)
1065 return ((const struct int_tree_map *)item)->uid;
1068 /* Return true if the DECL_UID in both trees are equal. */
1071 uid_decl_map_eq (const void *va, const void *vb)
1073 const_tree a = (const_tree) va;
1074 const_tree b = (const_tree) vb;
1075 return (a->decl_minimal.uid == b->decl_minimal.uid);
1078 /* Hash a tree in a uid_decl_map. */
1081 uid_decl_map_hash (const void *item)
1083 return ((const_tree)item)->decl_minimal.uid;
1086 /* Return true if the DECL_UID in both trees are equal. */
1089 uid_ssaname_map_eq (const void *va, const void *vb)
1091 const_tree a = (const_tree) va;
1092 const_tree b = (const_tree) vb;
1093 return (a->ssa_name.var->decl_minimal.uid == b->ssa_name.var->decl_minimal.uid);
1096 /* Hash a tree in a uid_decl_map. */
1099 uid_ssaname_map_hash (const void *item)
1101 return ((const_tree)item)->ssa_name.var->decl_minimal.uid;
1105 /* Initialize global DFA and SSA structures. */
1108 init_tree_ssa (struct function *fn)
1110 fn->gimple_df = GGC_CNEW (struct gimple_df);
1111 fn->gimple_df->referenced_vars = htab_create_ggc (20, uid_decl_map_hash,
1112 uid_decl_map_eq, NULL);
1113 fn->gimple_df->default_defs = htab_create_ggc (20, uid_ssaname_map_hash,
1114 uid_ssaname_map_eq, NULL);
1115 pt_solution_reset (&fn->gimple_df->escaped);
1116 pt_solution_reset (&fn->gimple_df->callused);
1117 init_ssanames (fn, 0);
1122 /* Deallocate memory associated with SSA data structures for FNDECL. */
1125 delete_tree_ssa (void)
1127 referenced_var_iterator rvi;
1130 /* Remove annotations from every referenced local variable. */
1131 FOR_EACH_REFERENCED_VAR (var, rvi)
1133 if (is_global_var (var))
1136 ggc_free (var->base.ann);
1137 var->base.ann = NULL;
1139 htab_delete (gimple_referenced_vars (cfun));
1140 cfun->gimple_df->referenced_vars = NULL;
1145 /* We no longer maintain the SSA operand cache at this point. */
1146 if (ssa_operands_active ())
1147 fini_ssa_operands ();
1149 delete_alias_heapvars ();
1151 htab_delete (cfun->gimple_df->default_defs);
1152 cfun->gimple_df->default_defs = NULL;
1153 pt_solution_reset (&cfun->gimple_df->escaped);
1154 pt_solution_reset (&cfun->gimple_df->callused);
1155 if (cfun->gimple_df->decls_to_pointers != NULL)
1156 pointer_map_destroy (cfun->gimple_df->decls_to_pointers);
1157 cfun->gimple_df->decls_to_pointers = NULL;
1158 cfun->gimple_df->modified_noreturn_calls = NULL;
1159 cfun->gimple_df = NULL;
1161 /* We no longer need the edge variable maps. */
1162 redirect_edge_var_map_destroy ();
1165 /* Return true if the conversion from INNER_TYPE to OUTER_TYPE is a
1166 useless type conversion, otherwise return false.
1168 This function implicitly defines the middle-end type system. With
1169 the notion of 'a < b' meaning that useless_type_conversion_p (a, b)
1170 holds and 'a > b' meaning that useless_type_conversion_p (b, a) holds,
1171 the following invariants shall be fulfilled:
1173 1) useless_type_conversion_p is transitive.
1174 If a < b and b < c then a < c.
1176 2) useless_type_conversion_p is not symmetric.
1177 From a < b does not follow a > b.
1179 3) Types define the available set of operations applicable to values.
1180 A type conversion is useless if the operations for the target type
1181 is a subset of the operations for the source type. For example
1182 casts to void* are useless, casts from void* are not (void* can't
1183 be dereferenced or offsetted, but copied, hence its set of operations
1184 is a strict subset of that of all other data pointer types). Casts
1185 to const T* are useless (can't be written to), casts from const T*
1189 useless_type_conversion_p (tree outer_type, tree inner_type)
1191 /* Do the following before stripping toplevel qualifiers. */
1192 if (POINTER_TYPE_P (inner_type)
1193 && POINTER_TYPE_P (outer_type))
1195 /* Do not lose casts between pointers to different address spaces. */
1196 if (TYPE_ADDR_SPACE (TREE_TYPE (outer_type))
1197 != TYPE_ADDR_SPACE (TREE_TYPE (inner_type)))
1200 /* If the outer type is (void *) or a pointer to an incomplete
1201 record type or a pointer to an unprototyped function,
1202 then the conversion is not necessary. */
1203 if (VOID_TYPE_P (TREE_TYPE (outer_type))
1204 || (AGGREGATE_TYPE_P (TREE_TYPE (outer_type))
1205 && TREE_CODE (TREE_TYPE (outer_type)) != ARRAY_TYPE
1206 && (TREE_CODE (TREE_TYPE (outer_type))
1207 == TREE_CODE (TREE_TYPE (inner_type)))
1208 && !COMPLETE_TYPE_P (TREE_TYPE (outer_type)))
1209 || ((TREE_CODE (TREE_TYPE (outer_type)) == FUNCTION_TYPE
1210 || TREE_CODE (TREE_TYPE (outer_type)) == METHOD_TYPE)
1211 && (TREE_CODE (TREE_TYPE (outer_type))
1212 == TREE_CODE (TREE_TYPE (inner_type)))
1213 && !TYPE_ARG_TYPES (TREE_TYPE (outer_type))
1214 && useless_type_conversion_p (TREE_TYPE (TREE_TYPE (outer_type)),
1215 TREE_TYPE (TREE_TYPE (inner_type)))))
1218 /* Do not lose casts to restrict qualified pointers. */
1219 if ((TYPE_RESTRICT (outer_type)
1220 != TYPE_RESTRICT (inner_type))
1221 && TYPE_RESTRICT (outer_type))
1225 /* From now on qualifiers on value types do not matter. */
1226 inner_type = TYPE_MAIN_VARIANT (inner_type);
1227 outer_type = TYPE_MAIN_VARIANT (outer_type);
1229 if (inner_type == outer_type)
1232 /* If we know the canonical types, compare them. */
1233 if (TYPE_CANONICAL (inner_type)
1234 && TYPE_CANONICAL (inner_type) == TYPE_CANONICAL (outer_type))
1237 /* Changes in machine mode are never useless conversions unless we
1238 deal with aggregate types in which case we defer to later checks. */
1239 if (TYPE_MODE (inner_type) != TYPE_MODE (outer_type)
1240 && !AGGREGATE_TYPE_P (inner_type))
1243 /* If both the inner and outer types are integral types, then the
1244 conversion is not necessary if they have the same mode and
1245 signedness and precision, and both or neither are boolean. */
1246 if (INTEGRAL_TYPE_P (inner_type)
1247 && INTEGRAL_TYPE_P (outer_type))
1249 /* Preserve changes in signedness or precision. */
1250 if (TYPE_UNSIGNED (inner_type) != TYPE_UNSIGNED (outer_type)
1251 || TYPE_PRECISION (inner_type) != TYPE_PRECISION (outer_type))
1254 /* We don't need to preserve changes in the types minimum or
1255 maximum value in general as these do not generate code
1256 unless the types precisions are different. */
1260 /* Scalar floating point types with the same mode are compatible. */
1261 else if (SCALAR_FLOAT_TYPE_P (inner_type)
1262 && SCALAR_FLOAT_TYPE_P (outer_type))
1265 /* Fixed point types with the same mode are compatible. */
1266 else if (FIXED_POINT_TYPE_P (inner_type)
1267 && FIXED_POINT_TYPE_P (outer_type))
1270 /* We need to take special care recursing to pointed-to types. */
1271 else if (POINTER_TYPE_P (inner_type)
1272 && POINTER_TYPE_P (outer_type))
1274 /* Don't lose casts between pointers to volatile and non-volatile
1275 qualified types. Doing so would result in changing the semantics
1276 of later accesses. For function types the volatile qualifier
1277 is used to indicate noreturn functions. */
1278 if (TREE_CODE (TREE_TYPE (outer_type)) != FUNCTION_TYPE
1279 && TREE_CODE (TREE_TYPE (outer_type)) != METHOD_TYPE
1280 && TREE_CODE (TREE_TYPE (inner_type)) != FUNCTION_TYPE
1281 && TREE_CODE (TREE_TYPE (inner_type)) != METHOD_TYPE
1282 && (TYPE_VOLATILE (TREE_TYPE (outer_type))
1283 != TYPE_VOLATILE (TREE_TYPE (inner_type)))
1284 && TYPE_VOLATILE (TREE_TYPE (outer_type)))
1287 /* We require explicit conversions from incomplete target types. */
1288 if (!COMPLETE_TYPE_P (TREE_TYPE (inner_type))
1289 && COMPLETE_TYPE_P (TREE_TYPE (outer_type)))
1292 /* Do not lose casts between pointers that when dereferenced access
1293 memory with different alias sets. */
1294 if (get_deref_alias_set (inner_type) != get_deref_alias_set (outer_type))
1297 /* We do not care for const qualification of the pointed-to types
1298 as const qualification has no semantic value to the middle-end. */
1300 /* Otherwise pointers/references are equivalent if their pointed
1301 to types are effectively the same. We can strip qualifiers
1302 on pointed-to types for further comparison, which is done in
1303 the callee. Note we have to use true compatibility here
1304 because addresses are subject to propagation into dereferences
1305 and thus might get the original type exposed which is equivalent
1306 to a reverse conversion. */
1307 return types_compatible_p (TREE_TYPE (outer_type),
1308 TREE_TYPE (inner_type));
1311 /* Recurse for complex types. */
1312 else if (TREE_CODE (inner_type) == COMPLEX_TYPE
1313 && TREE_CODE (outer_type) == COMPLEX_TYPE)
1314 return useless_type_conversion_p (TREE_TYPE (outer_type),
1315 TREE_TYPE (inner_type));
1317 /* Recurse for vector types with the same number of subparts. */
1318 else if (TREE_CODE (inner_type) == VECTOR_TYPE
1319 && TREE_CODE (outer_type) == VECTOR_TYPE
1320 && TYPE_PRECISION (inner_type) == TYPE_PRECISION (outer_type))
1321 return useless_type_conversion_p (TREE_TYPE (outer_type),
1322 TREE_TYPE (inner_type));
1324 else if (TREE_CODE (inner_type) == ARRAY_TYPE
1325 && TREE_CODE (outer_type) == ARRAY_TYPE)
1327 /* Preserve string attributes. */
1328 if (TYPE_STRING_FLAG (inner_type) != TYPE_STRING_FLAG (outer_type))
1331 /* Conversions from array types with unknown extent to
1332 array types with known extent are not useless. */
1333 if (!TYPE_DOMAIN (inner_type)
1334 && TYPE_DOMAIN (outer_type))
1337 /* Nor are conversions from array types with non-constant size to
1338 array types with constant size or to different size. */
1339 if (TYPE_SIZE (outer_type)
1340 && TREE_CODE (TYPE_SIZE (outer_type)) == INTEGER_CST
1341 && (!TYPE_SIZE (inner_type)
1342 || TREE_CODE (TYPE_SIZE (inner_type)) != INTEGER_CST
1343 || !tree_int_cst_equal (TYPE_SIZE (outer_type),
1344 TYPE_SIZE (inner_type))))
1347 /* Check conversions between arrays with partially known extents.
1348 If the array min/max values are constant they have to match.
1349 Otherwise allow conversions to unknown and variable extents.
1350 In particular this declares conversions that may change the
1351 mode to BLKmode as useless. */
1352 if (TYPE_DOMAIN (inner_type)
1353 && TYPE_DOMAIN (outer_type)
1354 && TYPE_DOMAIN (inner_type) != TYPE_DOMAIN (outer_type))
1356 tree inner_min = TYPE_MIN_VALUE (TYPE_DOMAIN (inner_type));
1357 tree outer_min = TYPE_MIN_VALUE (TYPE_DOMAIN (outer_type));
1358 tree inner_max = TYPE_MAX_VALUE (TYPE_DOMAIN (inner_type));
1359 tree outer_max = TYPE_MAX_VALUE (TYPE_DOMAIN (outer_type));
1361 /* After gimplification a variable min/max value carries no
1362 additional information compared to a NULL value. All that
1363 matters has been lowered to be part of the IL. */
1364 if (inner_min && TREE_CODE (inner_min) != INTEGER_CST)
1365 inner_min = NULL_TREE;
1366 if (outer_min && TREE_CODE (outer_min) != INTEGER_CST)
1367 outer_min = NULL_TREE;
1368 if (inner_max && TREE_CODE (inner_max) != INTEGER_CST)
1369 inner_max = NULL_TREE;
1370 if (outer_max && TREE_CODE (outer_max) != INTEGER_CST)
1371 outer_max = NULL_TREE;
1373 /* Conversions NULL / variable <- cst are useless, but not
1374 the other way around. */
1377 || !tree_int_cst_equal (inner_min, outer_min)))
1381 || !tree_int_cst_equal (inner_max, outer_max)))
1385 /* Recurse on the element check. */
1386 return useless_type_conversion_p (TREE_TYPE (outer_type),
1387 TREE_TYPE (inner_type));
1390 else if ((TREE_CODE (inner_type) == FUNCTION_TYPE
1391 || TREE_CODE (inner_type) == METHOD_TYPE)
1392 && TREE_CODE (inner_type) == TREE_CODE (outer_type))
1394 tree outer_parm, inner_parm;
1396 /* If the return types are not compatible bail out. */
1397 if (!useless_type_conversion_p (TREE_TYPE (outer_type),
1398 TREE_TYPE (inner_type)))
1401 /* Method types should belong to a compatible base class. */
1402 if (TREE_CODE (inner_type) == METHOD_TYPE
1403 && !useless_type_conversion_p (TYPE_METHOD_BASETYPE (outer_type),
1404 TYPE_METHOD_BASETYPE (inner_type)))
1407 /* A conversion to an unprototyped argument list is ok. */
1408 if (!TYPE_ARG_TYPES (outer_type))
1411 /* If the unqualified argument types are compatible the conversion
1413 if (TYPE_ARG_TYPES (outer_type) == TYPE_ARG_TYPES (inner_type))
1416 for (outer_parm = TYPE_ARG_TYPES (outer_type),
1417 inner_parm = TYPE_ARG_TYPES (inner_type);
1418 outer_parm && inner_parm;
1419 outer_parm = TREE_CHAIN (outer_parm),
1420 inner_parm = TREE_CHAIN (inner_parm))
1421 if (!useless_type_conversion_p
1422 (TYPE_MAIN_VARIANT (TREE_VALUE (outer_parm)),
1423 TYPE_MAIN_VARIANT (TREE_VALUE (inner_parm))))
1426 /* If there is a mismatch in the number of arguments the functions
1427 are not compatible. */
1428 if (outer_parm || inner_parm)
1431 /* Defer to the target if necessary. */
1432 if (TYPE_ATTRIBUTES (inner_type) || TYPE_ATTRIBUTES (outer_type))
1433 return targetm.comp_type_attributes (outer_type, inner_type) != 0;
1438 /* For aggregates we rely on TYPE_CANONICAL exclusively and require
1439 explicit conversions for types involving to be structurally
1441 else if (AGGREGATE_TYPE_P (inner_type)
1442 && TREE_CODE (inner_type) == TREE_CODE (outer_type))
1448 /* Return true if a conversion from either type of TYPE1 and TYPE2
1449 to the other is not required. Otherwise return false. */
1452 types_compatible_p (tree type1, tree type2)
1454 return (type1 == type2
1455 || (useless_type_conversion_p (type1, type2)
1456 && useless_type_conversion_p (type2, type1)));
1459 /* Return true if EXPR is a useless type conversion, otherwise return
1463 tree_ssa_useless_type_conversion (tree expr)
1465 /* If we have an assignment that merely uses a NOP_EXPR to change
1466 the top of the RHS to the type of the LHS and the type conversion
1467 is "safe", then strip away the type conversion so that we can
1468 enter LHS = RHS into the const_and_copies table. */
1469 if (CONVERT_EXPR_P (expr)
1470 || TREE_CODE (expr) == VIEW_CONVERT_EXPR
1471 || TREE_CODE (expr) == NON_LVALUE_EXPR)
1472 return useless_type_conversion_p
1474 TREE_TYPE (TREE_OPERAND (expr, 0)));
1479 /* Strip conversions from EXP according to
1480 tree_ssa_useless_type_conversion and return the resulting
1484 tree_ssa_strip_useless_type_conversions (tree exp)
1486 while (tree_ssa_useless_type_conversion (exp))
1487 exp = TREE_OPERAND (exp, 0);
1492 /* Internal helper for walk_use_def_chains. VAR, FN and DATA are as
1493 described in walk_use_def_chains.
1495 VISITED is a pointer set used to mark visited SSA_NAMEs to avoid
1496 infinite loops. We used to have a bitmap for this to just mark
1497 SSA versions we had visited. But non-sparse bitmaps are way too
1498 expensive, while sparse bitmaps may cause quadratic behavior.
1500 IS_DFS is true if the caller wants to perform a depth-first search
1501 when visiting PHI nodes. A DFS will visit each PHI argument and
1502 call FN after each one. Otherwise, all the arguments are
1503 visited first and then FN is called with each of the visited
1504 arguments in a separate pass. */
1507 walk_use_def_chains_1 (tree var, walk_use_def_chains_fn fn, void *data,
1508 struct pointer_set_t *visited, bool is_dfs)
1512 if (pointer_set_insert (visited, var))
1515 def_stmt = SSA_NAME_DEF_STMT (var);
1517 if (gimple_code (def_stmt) != GIMPLE_PHI)
1519 /* If we reached the end of the use-def chain, call FN. */
1520 return fn (var, def_stmt, data);
1526 /* When doing a breadth-first search, call FN before following the
1527 use-def links for each argument. */
1529 for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
1530 if (fn (gimple_phi_arg_def (def_stmt, i), def_stmt, data))
1533 /* Follow use-def links out of each PHI argument. */
1534 for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
1536 tree arg = gimple_phi_arg_def (def_stmt, i);
1538 /* ARG may be NULL for newly introduced PHI nodes. */
1540 && TREE_CODE (arg) == SSA_NAME
1541 && walk_use_def_chains_1 (arg, fn, data, visited, is_dfs))
1545 /* When doing a depth-first search, call FN after following the
1546 use-def links for each argument. */
1548 for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
1549 if (fn (gimple_phi_arg_def (def_stmt, i), def_stmt, data))
1558 /* Walk use-def chains starting at the SSA variable VAR. Call
1559 function FN at each reaching definition found. FN takes three
1560 arguments: VAR, its defining statement (DEF_STMT) and a generic
1561 pointer to whatever state information that FN may want to maintain
1562 (DATA). FN is able to stop the walk by returning true, otherwise
1563 in order to continue the walk, FN should return false.
1565 Note, that if DEF_STMT is a PHI node, the semantics are slightly
1566 different. The first argument to FN is no longer the original
1567 variable VAR, but the PHI argument currently being examined. If FN
1568 wants to get at VAR, it should call PHI_RESULT (PHI).
1570 If IS_DFS is true, this function will:
1572 1- walk the use-def chains for all the PHI arguments, and,
1573 2- call (*FN) (ARG, PHI, DATA) on all the PHI arguments.
1575 If IS_DFS is false, the two steps above are done in reverse order
1576 (i.e., a breadth-first search). */
1579 walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data,
1584 gcc_assert (TREE_CODE (var) == SSA_NAME);
1586 def_stmt = SSA_NAME_DEF_STMT (var);
1588 /* We only need to recurse if the reaching definition comes from a PHI
1590 if (gimple_code (def_stmt) != GIMPLE_PHI)
1591 (*fn) (var, def_stmt, data);
1594 struct pointer_set_t *visited = pointer_set_create ();
1595 walk_use_def_chains_1 (var, fn, data, visited, is_dfs);
1596 pointer_set_destroy (visited);
1601 /* Return true if T, an SSA_NAME, has an undefined value. */
1604 ssa_undefined_value_p (tree t)
1606 tree var = SSA_NAME_VAR (t);
1608 /* Parameters get their initial value from the function entry. */
1609 if (TREE_CODE (var) == PARM_DECL)
1612 /* Hard register variables get their initial value from the ether. */
1613 if (TREE_CODE (var) == VAR_DECL && DECL_HARD_REGISTER (var))
1616 /* The value is undefined iff its definition statement is empty. */
1617 return gimple_nop_p (SSA_NAME_DEF_STMT (t));
1620 /* Emit warnings for uninitialized variables. This is done in two passes.
1622 The first pass notices real uses of SSA names with undefined values.
1623 Such uses are unconditionally uninitialized, and we can be certain that
1624 such a use is a mistake. This pass is run before most optimizations,
1625 so that we catch as many as we can.
1627 The second pass follows PHI nodes to find uses that are potentially
1628 uninitialized. In this case we can't necessarily prove that the use
1629 is really uninitialized. This pass is run after most optimizations,
1630 so that we thread as many jumps and possible, and delete as much dead
1631 code as possible, in order to reduce false positives. We also look
1632 again for plain uninitialized variables, since optimization may have
1633 changed conditionally uninitialized to unconditionally uninitialized. */
1635 /* Emit a warning for T, an SSA_NAME, being uninitialized. The exact
1636 warning text is in MSGID and LOCUS may contain a location or be null. */
1639 warn_uninit (tree t, const char *gmsgid, void *data)
1641 tree var = SSA_NAME_VAR (t);
1642 gimple context = (gimple) data;
1643 location_t location;
1644 expanded_location xloc, floc;
1646 if (!ssa_undefined_value_p (t))
1649 /* TREE_NO_WARNING either means we already warned, or the front end
1650 wishes to suppress the warning. */
1651 if (TREE_NO_WARNING (var))
1654 /* Do not warn if it can be initialized outside this module. */
1655 if (is_global_var (var))
1658 location = (context != NULL && gimple_has_location (context))
1659 ? gimple_location (context)
1660 : DECL_SOURCE_LOCATION (var);
1661 xloc = expand_location (location);
1662 floc = expand_location (DECL_SOURCE_LOCATION (cfun->decl));
1663 if (warning_at (location, OPT_Wuninitialized, gmsgid, var))
1665 TREE_NO_WARNING (var) = 1;
1667 if (xloc.file != floc.file
1668 || xloc.line < floc.line
1669 || xloc.line > LOCATION_LINE (cfun->function_end_locus))
1670 inform (DECL_SOURCE_LOCATION (var), "%qD was declared here", var);
1676 bool always_executed;
1677 bool warn_possibly_uninitialized;
1680 /* Called via walk_tree, look for SSA_NAMEs that have empty definitions
1681 and warn about them. */
1684 warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data_)
1686 struct walk_stmt_info *wi = (struct walk_stmt_info *) data_;
1687 struct walk_data *data = (struct walk_data *) wi->info;
1690 /* We do not care about LHS. */
1693 /* Except for operands of INDIRECT_REF. */
1694 if (!INDIRECT_REF_P (t))
1696 t = TREE_OPERAND (t, 0);
1699 switch (TREE_CODE (t))
1702 /* Taking the address of an uninitialized variable does not
1703 count as using it. */
1709 /* A VAR_DECL in the RHS of a gimple statement may mean that
1710 this variable is loaded from memory. */
1714 /* If there is not gimple stmt,
1715 or alias information has not been computed,
1716 then we cannot check VUSE ops. */
1717 if (data->stmt == NULL)
1720 /* If the load happens as part of a call do not warn about it. */
1721 if (is_gimple_call (data->stmt))
1724 vuse = gimple_vuse_op (data->stmt);
1725 if (vuse == NULL_USE_OPERAND_P)
1728 op = USE_FROM_PTR (vuse);
1729 if (t != SSA_NAME_VAR (op)
1730 || !SSA_NAME_IS_DEFAULT_DEF (op))
1732 /* If this is a VUSE of t and it is the default definition,
1733 then warn about op. */
1735 /* Fall through into SSA_NAME. */
1739 /* We only do data flow with SSA_NAMEs, so that's all we
1741 if (data->always_executed)
1742 warn_uninit (t, "%qD is used uninitialized in this function",
1744 else if (data->warn_possibly_uninitialized)
1745 warn_uninit (t, "%qD may be used uninitialized in this function",
1752 /* The total store transformation performed during gimplification
1753 creates uninitialized variable uses. If all is well, these will
1754 be optimized away, so don't warn now. */
1755 if (TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME)
1760 if (IS_TYPE_OR_DECL_P (t))
1768 /* Look for inputs to PHI that are SSA_NAMEs that have empty definitions
1769 and warn about them. */
1772 warn_uninitialized_phi (gimple phi)
1774 size_t i, n = gimple_phi_num_args (phi);
1776 /* Don't look at memory tags. */
1777 if (!is_gimple_reg (gimple_phi_result (phi)))
1780 for (i = 0; i < n; ++i)
1782 tree op = gimple_phi_arg_def (phi, i);
1783 if (TREE_CODE (op) == SSA_NAME)
1784 warn_uninit (op, "%qD may be used uninitialized in this function",
1790 warn_uninitialized_vars (bool warn_possibly_uninitialized)
1792 gimple_stmt_iterator gsi;
1794 struct walk_data data;
1796 data.warn_possibly_uninitialized = warn_possibly_uninitialized;
1798 calculate_dominance_info (CDI_POST_DOMINATORS);
1802 data.always_executed = dominated_by_p (CDI_POST_DOMINATORS,
1803 single_succ (ENTRY_BLOCK_PTR), bb);
1804 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1806 struct walk_stmt_info wi;
1807 data.stmt = gsi_stmt (gsi);
1808 if (is_gimple_debug (data.stmt))
1810 memset (&wi, 0, sizeof (wi));
1812 walk_gimple_op (gsi_stmt (gsi), warn_uninitialized_var, &wi);
1816 /* Post-dominator information can not be reliably updated. Free it
1819 free_dominance_info (CDI_POST_DOMINATORS);
1824 execute_early_warn_uninitialized (void)
1826 /* Currently, this pass runs always but
1827 execute_late_warn_uninitialized only runs with optimization. With
1828 optimization we want to warn about possible uninitialized as late
1829 as possible, thus don't do it here. However, without
1830 optimization we need to warn here about "may be uninitialized".
1832 warn_uninitialized_vars (/*warn_possibly_uninitialized=*/!optimize);
1837 execute_late_warn_uninitialized (void)
1840 gimple_stmt_iterator gsi;
1842 /* Re-do the plain uninitialized variable check, as optimization may have
1843 straightened control flow. Do this first so that we don't accidentally
1844 get a "may be" warning when we'd have seen an "is" warning later. */
1845 warn_uninitialized_vars (/*warn_possibly_uninitialized=*/1);
1848 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1849 warn_uninitialized_phi (gsi_stmt (gsi));
1855 gate_warn_uninitialized (void)
1857 return warn_uninitialized != 0;
1860 struct gimple_opt_pass pass_early_warn_uninitialized =
1865 gate_warn_uninitialized, /* gate */
1866 execute_early_warn_uninitialized, /* execute */
1869 0, /* static_pass_number */
1870 TV_NONE, /* tv_id */
1871 PROP_ssa, /* properties_required */
1872 0, /* properties_provided */
1873 0, /* properties_destroyed */
1874 0, /* todo_flags_start */
1875 0 /* todo_flags_finish */
1879 struct gimple_opt_pass pass_late_warn_uninitialized =
1884 gate_warn_uninitialized, /* gate */
1885 execute_late_warn_uninitialized, /* execute */
1888 0, /* static_pass_number */
1889 TV_NONE, /* tv_id */
1890 PROP_ssa, /* properties_required */
1891 0, /* properties_provided */
1892 0, /* properties_destroyed */
1893 0, /* todo_flags_start */
1894 0 /* todo_flags_finish */
1898 /* Compute TREE_ADDRESSABLE and DECL_GIMPLE_REG_P for local variables. */
1901 execute_update_addresses_taken (bool do_optimize)
1904 referenced_var_iterator rvi;
1905 gimple_stmt_iterator gsi;
1907 bitmap addresses_taken = BITMAP_ALLOC (NULL);
1908 bitmap not_reg_needs = BITMAP_ALLOC (NULL);
1909 bool update_vops = false;
1911 /* Collect into ADDRESSES_TAKEN all variables whose address is taken within
1912 the function body. */
1915 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1917 gimple stmt = gsi_stmt (gsi);
1918 enum gimple_code code = gimple_code (stmt);
1920 /* Note all addresses taken by the stmt. */
1921 gimple_ior_addresses_taken (addresses_taken, stmt);
1923 /* If we have a call or an assignment, see if the lhs contains
1924 a local decl that requires not to be a gimple register. */
1925 if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL)
1927 tree lhs = gimple_get_lhs (stmt);
1929 /* We may not rewrite TMR_SYMBOL to SSA. */
1930 if (lhs && TREE_CODE (lhs) == TARGET_MEM_REF
1931 && TMR_SYMBOL (lhs))
1932 bitmap_set_bit (not_reg_needs, DECL_UID (TMR_SYMBOL (lhs)));
1934 /* A plain decl does not need it set. */
1935 else if (lhs && handled_component_p (lhs))
1937 var = get_base_address (lhs);
1939 bitmap_set_bit (not_reg_needs, DECL_UID (var));
1944 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1947 gimple phi = gsi_stmt (gsi);
1949 for (i = 0; i < gimple_phi_num_args (phi); i++)
1951 tree op = PHI_ARG_DEF (phi, i), var;
1952 if (TREE_CODE (op) == ADDR_EXPR
1953 && (var = get_base_address (TREE_OPERAND (op, 0))) != NULL
1955 bitmap_set_bit (addresses_taken, DECL_UID (var));
1960 /* When possible, clear ADDRESSABLE bit or set the REGISTER bit
1961 and mark variable for conversion into SSA. */
1962 if (optimize && do_optimize)
1963 FOR_EACH_REFERENCED_VAR (var, rvi)
1965 /* Global Variables, result decls cannot be changed. */
1966 if (is_global_var (var)
1967 || TREE_CODE (var) == RESULT_DECL
1968 || bitmap_bit_p (addresses_taken, DECL_UID (var)))
1971 if (TREE_ADDRESSABLE (var)
1972 /* Do not change TREE_ADDRESSABLE if we need to preserve var as
1973 a non-register. Otherwise we are confused and forget to
1974 add virtual operands for it. */
1975 && (!is_gimple_reg_type (TREE_TYPE (var))
1976 || !bitmap_bit_p (not_reg_needs, DECL_UID (var))))
1978 TREE_ADDRESSABLE (var) = 0;
1979 if (is_gimple_reg (var))
1980 mark_sym_for_renaming (var);
1984 fprintf (dump_file, "No longer having address taken ");
1985 print_generic_expr (dump_file, var, 0);
1986 fprintf (dump_file, "\n");
1989 if (!DECL_GIMPLE_REG_P (var)
1990 && !bitmap_bit_p (not_reg_needs, DECL_UID (var))
1991 && (TREE_CODE (TREE_TYPE (var)) == COMPLEX_TYPE
1992 || TREE_CODE (TREE_TYPE (var)) == VECTOR_TYPE)
1993 && !TREE_THIS_VOLATILE (var)
1994 && (TREE_CODE (var) != VAR_DECL || !DECL_HARD_REGISTER (var)))
1996 DECL_GIMPLE_REG_P (var) = 1;
1997 mark_sym_for_renaming (var);
2001 fprintf (dump_file, "Decl is now a gimple register ");
2002 print_generic_expr (dump_file, var, 0);
2003 fprintf (dump_file, "\n");
2008 /* Operand caches needs to be recomputed for operands referencing the updated
2013 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
2015 gimple stmt = gsi_stmt (gsi);
2017 if (gimple_references_memory_p (stmt)
2018 || is_gimple_debug (stmt))
2022 /* Update SSA form here, we are called as non-pass as well. */
2023 update_ssa (TODO_update_ssa);
2026 BITMAP_FREE (not_reg_needs);
2027 BITMAP_FREE (addresses_taken);
2030 struct gimple_opt_pass pass_update_address_taken =
2034 "addressables", /* name */
2039 0, /* static_pass_number */
2040 TV_NONE, /* tv_id */
2041 PROP_ssa, /* properties_required */
2042 0, /* properties_provided */
2043 0, /* properties_destroyed */
2044 0, /* todo_flags_start */
2045 TODO_update_address_taken
2046 | TODO_dump_func /* todo_flags_finish */