1 /* Miscellaneous SSA utility functions.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
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"
30 #include "langhooks.h"
31 #include "basic-block.h"
34 #include "tree-pretty-print.h"
35 #include "gimple-pretty-print.h"
37 #include "pointer-set.h"
38 #include "tree-flow.h"
40 #include "tree-inline.h"
43 #include "tree-dump.h"
44 #include "tree-pass.h"
45 #include "diagnostic-core.h"
48 /* Pointer map of variable mappings, keyed by edge. */
49 static struct pointer_map_t *edge_var_maps;
52 /* Add a mapping with PHI RESULT and PHI DEF associated with edge E. */
55 redirect_edge_var_map_add (edge e, tree result, tree def, source_location locus)
58 edge_var_map_vector old_head, head;
59 edge_var_map new_node;
61 if (edge_var_maps == NULL)
62 edge_var_maps = pointer_map_create ();
64 slot = pointer_map_insert (edge_var_maps, e);
65 old_head = head = (edge_var_map_vector) *slot;
68 head = VEC_alloc (edge_var_map, heap, 5);
72 new_node.result = result;
73 new_node.locus = locus;
75 VEC_safe_push (edge_var_map, heap, head, &new_node);
78 /* The push did some reallocation. Update the pointer map. */
84 /* Clear the var mappings in edge E. */
87 redirect_edge_var_map_clear (edge e)
90 edge_var_map_vector head;
95 slot = pointer_map_contains (edge_var_maps, e);
99 head = (edge_var_map_vector) *slot;
100 VEC_free (edge_var_map, heap, head);
106 /* Duplicate the redirected var mappings in OLDE in NEWE.
108 Since we can't remove a mapping, let's just duplicate it. This assumes a
109 pointer_map can have multiple edges mapping to the same var_map (many to
110 one mapping), since we don't remove the previous mappings. */
113 redirect_edge_var_map_dup (edge newe, edge olde)
115 void **new_slot, **old_slot;
116 edge_var_map_vector head;
121 new_slot = pointer_map_insert (edge_var_maps, newe);
122 old_slot = pointer_map_contains (edge_var_maps, olde);
125 head = (edge_var_map_vector) *old_slot;
128 *new_slot = VEC_copy (edge_var_map, heap, head);
130 *new_slot = VEC_alloc (edge_var_map, heap, 5);
134 /* Return the variable mappings for a given edge. If there is none, return
138 redirect_edge_var_map_vector (edge e)
142 /* Hey, what kind of idiot would... you'd be surprised. */
146 slot = pointer_map_contains (edge_var_maps, e);
150 return (edge_var_map_vector) *slot;
153 /* Used by redirect_edge_var_map_destroy to free all memory. */
156 free_var_map_entry (const void *key ATTRIBUTE_UNUSED,
158 void *data ATTRIBUTE_UNUSED)
160 edge_var_map_vector head = (edge_var_map_vector) *value;
161 VEC_free (edge_var_map, heap, head);
165 /* Clear the edge variable mappings. */
168 redirect_edge_var_map_destroy (void)
172 pointer_map_traverse (edge_var_maps, free_var_map_entry, NULL);
173 pointer_map_destroy (edge_var_maps);
174 edge_var_maps = NULL;
179 /* Remove the corresponding arguments from the PHI nodes in E's
180 destination block and redirect it to DEST. Return redirected edge.
181 The list of removed arguments is stored in a vector accessed
182 through edge_var_maps. */
185 ssa_redirect_edge (edge e, basic_block dest)
187 gimple_stmt_iterator gsi;
190 redirect_edge_var_map_clear (e);
192 /* Remove the appropriate PHI arguments in E's destination block. */
193 for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
196 source_location locus ;
198 phi = gsi_stmt (gsi);
199 def = gimple_phi_arg_def (phi, e->dest_idx);
200 locus = gimple_phi_arg_location (phi, e->dest_idx);
202 if (def == NULL_TREE)
205 redirect_edge_var_map_add (e, gimple_phi_result (phi), def, locus);
208 e = redirect_edge_succ_nodup (e, dest);
214 /* Add PHI arguments queued in PENDING_STMT list on edge E to edge
218 flush_pending_stmts (edge e)
221 edge_var_map_vector v;
224 gimple_stmt_iterator gsi;
226 v = redirect_edge_var_map_vector (e);
230 for (gsi = gsi_start_phis (e->dest), i = 0;
231 !gsi_end_p (gsi) && VEC_iterate (edge_var_map, v, i, vm);
232 gsi_next (&gsi), i++)
236 phi = gsi_stmt (gsi);
237 def = redirect_edge_var_map_def (vm);
238 add_phi_arg (phi, def, e, redirect_edge_var_map_location (vm));
241 redirect_edge_var_map_clear (e);
244 /* Given a tree for an expression for which we might want to emit
245 locations or values in debug information (generally a variable, but
246 we might deal with other kinds of trees in the future), return the
247 tree that should be used as the variable of a DEBUG_BIND STMT or
248 VAR_LOCATION INSN or NOTE. Return NULL if VAR is not to be tracked. */
251 target_for_debug_bind (tree var)
253 if (!MAY_HAVE_DEBUG_STMTS)
256 if (TREE_CODE (var) != VAR_DECL
257 && TREE_CODE (var) != PARM_DECL)
260 if (DECL_HAS_VALUE_EXPR_P (var))
261 return target_for_debug_bind (DECL_VALUE_EXPR (var));
263 if (DECL_IGNORED_P (var))
266 if (!is_gimple_reg (var))
272 /* Called via walk_tree, look for SSA_NAMEs that have already been
276 find_released_ssa_name (tree *tp, int *walk_subtrees, void *data_)
278 struct walk_stmt_info *wi = (struct walk_stmt_info *) data_;
280 if (wi && wi->is_lhs)
283 if (TREE_CODE (*tp) == SSA_NAME)
285 if (SSA_NAME_IN_FREE_LIST (*tp))
290 else if (IS_TYPE_OR_DECL_P (*tp))
296 /* Insert a DEBUG BIND stmt before the DEF of VAR if VAR is referenced
297 by other DEBUG stmts, and replace uses of the DEF with the
298 newly-created debug temp. */
301 insert_debug_temp_for_var_def (gimple_stmt_iterator *gsi, tree var)
303 imm_use_iterator imm_iter;
306 gimple def_stmt = NULL;
310 if (!MAY_HAVE_DEBUG_STMTS)
313 /* If this name has already been registered for replacement, do nothing
314 as anything that uses this name isn't in SSA form. */
315 if (name_registered_for_update_p (var))
318 /* Check whether there are debug stmts that reference this variable and,
319 if there are, decide whether we should use a debug temp. */
320 FOR_EACH_IMM_USE_FAST (use_p, imm_iter, var)
322 stmt = USE_STMT (use_p);
324 if (!gimple_debug_bind_p (stmt))
330 if (gimple_debug_bind_get_value (stmt) != var)
332 /* Count this as an additional use, so as to make sure we
333 use a temp unless VAR's definition has a SINGLE_RHS that
344 def_stmt = gsi_stmt (*gsi);
346 def_stmt = SSA_NAME_DEF_STMT (var);
348 /* If we didn't get an insertion point, and the stmt has already
349 been removed, we won't be able to insert the debug bind stmt, so
350 we'll have to drop debug information. */
351 if (gimple_code (def_stmt) == GIMPLE_PHI)
353 value = degenerate_phi_result (def_stmt);
354 if (value && walk_tree (&value, find_released_ssa_name, NULL, NULL))
356 /* error_mark_node is what fixup_noreturn_call changes PHI arguments
358 else if (value == error_mark_node)
361 else if (is_gimple_assign (def_stmt))
363 bool no_value = false;
365 if (!dom_info_available_p (CDI_DOMINATORS))
367 struct walk_stmt_info wi;
369 memset (&wi, 0, sizeof (wi));
371 /* When removing blocks without following reverse dominance
372 order, we may sometimes encounter SSA_NAMEs that have
373 already been released, referenced in other SSA_DEFs that
374 we're about to release. Consider:
383 If we deleted BB X first, propagating the value of w_2
384 won't do us any good. It's too late to recover their
385 original definition of v_1: when it was deleted, it was
386 only referenced in other DEFs, it couldn't possibly know
387 it should have been retained, and propagating every
388 single DEF just in case it might have to be propagated
389 into a DEBUG STMT would probably be too wasteful.
391 When dominator information is not readily available, we
392 check for and accept some loss of debug information. But
393 if it is available, there's no excuse for us to remove
394 blocks in the wrong order, so we don't even check for
395 dead SSA NAMEs. SSA verification shall catch any
397 if ((!gsi && !gimple_bb (def_stmt))
398 || walk_gimple_op (def_stmt, find_released_ssa_name, &wi))
403 value = gimple_assign_rhs_to_tree (def_stmt);
408 /* If there's a single use of VAR, and VAR is the entire debug
409 expression (usecount would have been incremented again
410 otherwise), and the definition involves only constants and
411 SSA names, then we can propagate VALUE into this single use,
414 We can also avoid using a temp if VALUE can be shared and
415 propagated into all uses, without generating expressions that
416 wouldn't be valid gimple RHSs.
418 Other cases that would require unsharing or non-gimple RHSs
419 are deferred to a debug temp, although we could avoid temps
420 at the expense of duplication of expressions. */
422 if (CONSTANT_CLASS_P (value)
423 || gimple_code (def_stmt) == GIMPLE_PHI
425 && (!gimple_assign_single_p (def_stmt)
426 || is_gimple_min_invariant (value)))
427 || is_gimple_reg (value))
428 value = unshare_expr (value);
432 tree vexpr = make_node (DEBUG_EXPR_DECL);
434 def_temp = gimple_build_debug_bind (vexpr,
435 unshare_expr (value),
438 DECL_ARTIFICIAL (vexpr) = 1;
439 TREE_TYPE (vexpr) = TREE_TYPE (value);
441 DECL_MODE (vexpr) = DECL_MODE (value);
443 DECL_MODE (vexpr) = TYPE_MODE (TREE_TYPE (value));
446 gsi_insert_before (gsi, def_temp, GSI_SAME_STMT);
449 gimple_stmt_iterator ngsi = gsi_for_stmt (def_stmt);
450 gsi_insert_before (&ngsi, def_temp, GSI_SAME_STMT);
457 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, var)
459 if (!gimple_debug_bind_p (stmt))
464 FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
465 /* unshare_expr is not needed here. vexpr is either a
466 SINGLE_RHS, that can be safely shared, some other RHS
467 that was unshared when we found it had a single debug
468 use, or a DEBUG_EXPR_DECL, that can be safely
470 SET_USE (use_p, value);
471 /* If we didn't replace uses with a debug decl fold the
472 resulting expression. Otherwise we end up with invalid IL. */
473 if (TREE_CODE (value) != DEBUG_EXPR_DECL)
474 fold_stmt_inplace (stmt);
477 gimple_debug_bind_reset_value (stmt);
484 /* Insert a DEBUG BIND stmt before STMT for each DEF referenced by
485 other DEBUG stmts, and replace uses of the DEF with the
486 newly-created debug temp. */
489 insert_debug_temps_for_defs (gimple_stmt_iterator *gsi)
495 if (!MAY_HAVE_DEBUG_STMTS)
498 stmt = gsi_stmt (*gsi);
500 FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, op_iter, SSA_OP_DEF)
502 tree var = DEF_FROM_PTR (def_p);
504 if (TREE_CODE (var) != SSA_NAME)
507 insert_debug_temp_for_var_def (gsi, var);
511 /* Reset all debug stmts that use SSA_NAME(s) defined in STMT. */
514 reset_debug_uses (gimple stmt)
518 imm_use_iterator imm_iter;
521 if (!MAY_HAVE_DEBUG_STMTS)
524 FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, op_iter, SSA_OP_DEF)
526 tree var = DEF_FROM_PTR (def_p);
528 if (TREE_CODE (var) != SSA_NAME)
531 FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, var)
533 if (!gimple_debug_bind_p (use_stmt))
536 gimple_debug_bind_reset_value (use_stmt);
537 update_stmt (use_stmt);
542 /* Delete SSA DEFs for SSA versions in the TOREMOVE bitmap, removing
543 dominated stmts before their dominators, so that release_ssa_defs
544 stands a chance of propagating DEFs into debug bind stmts. */
547 release_defs_bitset (bitmap toremove)
552 /* Performing a topological sort is probably overkill, this will
553 most likely run in slightly superlinear time, rather than the
554 pathological quadratic worst case. */
555 while (!bitmap_empty_p (toremove))
556 EXECUTE_IF_SET_IN_BITMAP (toremove, 0, j, bi)
558 bool remove_now = true;
559 tree var = ssa_name (j);
561 imm_use_iterator uit;
563 FOR_EACH_IMM_USE_STMT (stmt, uit, var)
568 /* We can't propagate PHI nodes into debug stmts. */
569 if (gimple_code (stmt) == GIMPLE_PHI
570 || is_gimple_debug (stmt))
573 /* If we find another definition to remove that uses
574 the one we're looking at, defer the removal of this
575 one, so that it can be propagated into debug stmts
576 after the other is. */
577 FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, dit, SSA_OP_DEF)
579 tree odef = DEF_FROM_PTR (def_p);
581 if (bitmap_bit_p (toremove, SSA_NAME_VERSION (odef)))
589 BREAK_FROM_IMM_USE_STMT (uit);
594 gimple def = SSA_NAME_DEF_STMT (var);
595 gimple_stmt_iterator gsi = gsi_for_stmt (def);
597 if (gimple_code (def) == GIMPLE_PHI)
598 remove_phi_node (&gsi, true);
601 gsi_remove (&gsi, true);
605 bitmap_clear_bit (toremove, j);
610 /* Return true if SSA_NAME is malformed and mark it visited.
612 IS_VIRTUAL is true if this SSA_NAME was found inside a virtual
616 verify_ssa_name (tree ssa_name, bool is_virtual)
618 if (TREE_CODE (ssa_name) != SSA_NAME)
620 error ("expected an SSA_NAME object");
624 if (TREE_TYPE (ssa_name) != TREE_TYPE (SSA_NAME_VAR (ssa_name)))
626 error ("type mismatch between an SSA_NAME and its symbol");
630 if (SSA_NAME_IN_FREE_LIST (ssa_name))
632 error ("found an SSA_NAME that had been released into the free pool");
636 if (is_virtual && is_gimple_reg (ssa_name))
638 error ("found a virtual definition for a GIMPLE register");
642 if (is_virtual && SSA_NAME_VAR (ssa_name) != gimple_vop (cfun))
644 error ("virtual SSA name for non-VOP decl");
648 if (!is_virtual && !is_gimple_reg (ssa_name))
650 error ("found a real definition for a non-register");
654 if (SSA_NAME_IS_DEFAULT_DEF (ssa_name)
655 && !gimple_nop_p (SSA_NAME_DEF_STMT (ssa_name)))
657 error ("found a default name with a non-empty defining statement");
665 /* Return true if the definition of SSA_NAME at block BB is malformed.
667 STMT is the statement where SSA_NAME is created.
669 DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME
670 version numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set,
671 it means that the block in that array slot contains the
672 definition of SSA_NAME.
674 IS_VIRTUAL is true if SSA_NAME is created by a VDEF. */
677 verify_def (basic_block bb, basic_block *definition_block, tree ssa_name,
678 gimple stmt, bool is_virtual)
680 if (verify_ssa_name (ssa_name, is_virtual))
683 if (TREE_CODE (SSA_NAME_VAR (ssa_name)) == RESULT_DECL
684 && DECL_BY_REFERENCE (SSA_NAME_VAR (ssa_name)))
686 error ("RESULT_DECL should be read only when DECL_BY_REFERENCE is set");
690 if (definition_block[SSA_NAME_VERSION (ssa_name)])
692 error ("SSA_NAME created in two different blocks %i and %i",
693 definition_block[SSA_NAME_VERSION (ssa_name)]->index, bb->index);
697 definition_block[SSA_NAME_VERSION (ssa_name)] = bb;
699 if (SSA_NAME_DEF_STMT (ssa_name) != stmt)
701 error ("SSA_NAME_DEF_STMT is wrong");
702 fprintf (stderr, "Expected definition statement:\n");
703 print_gimple_stmt (stderr, SSA_NAME_DEF_STMT (ssa_name), 4, TDF_VOPS);
704 fprintf (stderr, "\nActual definition statement:\n");
705 print_gimple_stmt (stderr, stmt, 4, TDF_VOPS);
712 fprintf (stderr, "while verifying SSA_NAME ");
713 print_generic_expr (stderr, ssa_name, 0);
714 fprintf (stderr, " in statement\n");
715 print_gimple_stmt (stderr, stmt, 4, TDF_VOPS);
721 /* Return true if the use of SSA_NAME at statement STMT in block BB is
724 DEF_BB is the block where SSA_NAME was found to be created.
726 IDOM contains immediate dominator information for the flowgraph.
728 CHECK_ABNORMAL is true if the caller wants to check whether this use
729 is flowing through an abnormal edge (only used when checking PHI
732 If NAMES_DEFINED_IN_BB is not NULL, it contains a bitmap of ssa names
733 that are defined before STMT in basic block BB. */
736 verify_use (basic_block bb, basic_block def_bb, use_operand_p use_p,
737 gimple stmt, bool check_abnormal, bitmap names_defined_in_bb)
740 tree ssa_name = USE_FROM_PTR (use_p);
742 if (!TREE_VISITED (ssa_name))
743 if (verify_imm_links (stderr, ssa_name))
746 TREE_VISITED (ssa_name) = 1;
748 if (gimple_nop_p (SSA_NAME_DEF_STMT (ssa_name))
749 && SSA_NAME_IS_DEFAULT_DEF (ssa_name))
750 ; /* Default definitions have empty statements. Nothing to do. */
753 error ("missing definition");
756 else if (bb != def_bb
757 && !dominated_by_p (CDI_DOMINATORS, bb, def_bb))
759 error ("definition in block %i does not dominate use in block %i",
760 def_bb->index, bb->index);
763 else if (bb == def_bb
764 && names_defined_in_bb != NULL
765 && !bitmap_bit_p (names_defined_in_bb, SSA_NAME_VERSION (ssa_name)))
767 error ("definition in block %i follows the use", def_bb->index);
772 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ssa_name))
774 error ("SSA_NAME_OCCURS_IN_ABNORMAL_PHI should be set");
778 /* Make sure the use is in an appropriate list by checking the previous
779 element to make sure it's the same. */
780 if (use_p->prev == NULL)
782 error ("no immediate_use list");
788 if (use_p->prev->use == NULL)
789 listvar = use_p->prev->loc.ssa_name;
791 listvar = USE_FROM_PTR (use_p->prev);
792 if (listvar != ssa_name)
794 error ("wrong immediate use list");
801 fprintf (stderr, "for SSA_NAME: ");
802 print_generic_expr (stderr, ssa_name, TDF_VOPS);
803 fprintf (stderr, " in statement:\n");
804 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS);
811 /* Return true if any of the arguments for PHI node PHI at block BB is
814 DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME
815 version numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set,
816 it means that the block in that array slot contains the
817 definition of SSA_NAME. */
820 verify_phi_args (gimple phi, basic_block bb, basic_block *definition_block)
824 size_t i, phi_num_args = gimple_phi_num_args (phi);
826 if (EDGE_COUNT (bb->preds) != phi_num_args)
828 error ("incoming edge count does not match number of PHI arguments");
833 for (i = 0; i < phi_num_args; i++)
835 use_operand_p op_p = gimple_phi_arg_imm_use_ptr (phi, i);
836 tree op = USE_FROM_PTR (op_p);
838 e = EDGE_PRED (bb, i);
842 error ("PHI argument is missing for edge %d->%d",
849 if (TREE_CODE (op) != SSA_NAME && !is_gimple_min_invariant (op))
851 error ("PHI argument is not SSA_NAME, or invariant");
855 if (TREE_CODE (op) == SSA_NAME)
857 err = verify_ssa_name (op, !is_gimple_reg (gimple_phi_result (phi)));
858 err |= verify_use (e->src, definition_block[SSA_NAME_VERSION (op)],
859 op_p, phi, e->flags & EDGE_ABNORMAL, NULL);
862 if (TREE_CODE (op) == ADDR_EXPR)
864 tree base = TREE_OPERAND (op, 0);
865 while (handled_component_p (base))
866 base = TREE_OPERAND (base, 0);
867 if ((TREE_CODE (base) == VAR_DECL
868 || TREE_CODE (base) == PARM_DECL
869 || TREE_CODE (base) == RESULT_DECL)
870 && !TREE_ADDRESSABLE (base))
872 error ("address taken, but ADDRESSABLE bit not set");
879 error ("wrong edge %d->%d for PHI argument",
880 e->src->index, e->dest->index);
886 fprintf (stderr, "PHI argument\n");
887 print_generic_stmt (stderr, op, TDF_VOPS);
895 fprintf (stderr, "for PHI node\n");
896 print_gimple_stmt (stderr, phi, 0, TDF_VOPS|TDF_MEMSYMS);
904 /* Verify common invariants in the SSA web.
905 TODO: verify the variable annotations. */
908 verify_ssa (bool check_modified_stmt)
912 basic_block *definition_block = XCNEWVEC (basic_block, num_ssa_names);
915 enum dom_state orig_dom_state = dom_info_state (CDI_DOMINATORS);
916 bitmap names_defined_in_bb = BITMAP_ALLOC (NULL);
918 gcc_assert (!need_ssa_update_p (cfun));
922 timevar_push (TV_TREE_SSA_VERIFY);
924 /* Keep track of SSA names present in the IL. */
925 for (i = 1; i < num_ssa_names; i++)
927 tree name = ssa_name (i);
931 TREE_VISITED (name) = 0;
933 stmt = SSA_NAME_DEF_STMT (name);
934 if (!gimple_nop_p (stmt))
936 basic_block bb = gimple_bb (stmt);
937 verify_def (bb, definition_block,
938 name, stmt, !is_gimple_reg (name));
944 calculate_dominance_info (CDI_DOMINATORS);
946 /* Now verify all the uses and make sure they agree with the definitions
947 found in the previous pass. */
953 gimple_stmt_iterator gsi;
955 /* Make sure that all edges have a clear 'aux' field. */
956 FOR_EACH_EDGE (e, ei, bb->preds)
960 error ("AUX pointer initialized for edge %d->%d", e->src->index,
966 /* Verify the arguments for every PHI node in the block. */
967 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
969 phi = gsi_stmt (gsi);
970 if (verify_phi_args (phi, bb, definition_block))
973 bitmap_set_bit (names_defined_in_bb,
974 SSA_NAME_VERSION (gimple_phi_result (phi)));
977 /* Now verify all the uses and vuses in every statement of the block. */
978 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
980 gimple stmt = gsi_stmt (gsi);
986 if (check_modified_stmt && gimple_modified_p (stmt))
988 error ("stmt (%p) marked modified after optimization pass: ",
990 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS);
994 if (is_gimple_assign (stmt)
995 && TREE_CODE (gimple_assign_lhs (stmt)) != SSA_NAME)
997 tree lhs, base_address;
999 lhs = gimple_assign_lhs (stmt);
1000 base_address = get_base_address (lhs);
1003 && SSA_VAR_P (base_address)
1004 && !gimple_vdef (stmt)
1007 error ("statement makes a memory store, but has no VDEFS");
1008 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS);
1012 else if (gimple_debug_bind_p (stmt)
1013 && !gimple_debug_bind_has_value_p (stmt))
1016 /* Verify the single virtual operand and its constraints. */
1018 if (gimple_vdef (stmt))
1020 if (gimple_vdef_op (stmt) == NULL_DEF_OPERAND_P)
1022 error ("statement has VDEF operand not in defs list");
1025 if (!gimple_vuse (stmt))
1027 error ("statement has VDEF but no VUSE operand");
1030 else if (SSA_NAME_VAR (gimple_vdef (stmt))
1031 != SSA_NAME_VAR (gimple_vuse (stmt)))
1033 error ("VDEF and VUSE do not use the same symbol");
1036 has_err |= verify_ssa_name (gimple_vdef (stmt), true);
1038 if (gimple_vuse (stmt))
1040 if (gimple_vuse_op (stmt) == NULL_USE_OPERAND_P)
1042 error ("statement has VUSE operand not in uses list");
1045 has_err |= verify_ssa_name (gimple_vuse (stmt), true);
1049 error ("in statement");
1050 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS|TDF_MEMSYMS);
1055 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE|SSA_OP_DEF)
1057 if (verify_ssa_name (op, false))
1059 error ("in statement");
1060 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS|TDF_MEMSYMS);
1066 for (i = 0; i < gimple_num_ops (stmt); i++)
1068 op = gimple_op (stmt, i);
1069 if (op && TREE_CODE (op) == SSA_NAME && --count < 0)
1071 error ("number of operands and imm-links don%'t agree"
1073 print_gimple_stmt (stderr, stmt, 0, TDF_VOPS|TDF_MEMSYMS);
1078 FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE|SSA_OP_VUSE)
1080 op = USE_FROM_PTR (use_p);
1081 if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)],
1082 use_p, stmt, false, names_defined_in_bb))
1086 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_ALL_DEFS)
1088 if (SSA_NAME_DEF_STMT (op) != stmt)
1090 error ("SSA_NAME_DEF_STMT is wrong");
1091 fprintf (stderr, "Expected definition statement:\n");
1092 print_gimple_stmt (stderr, stmt, 4, TDF_VOPS);
1093 fprintf (stderr, "\nActual definition statement:\n");
1094 print_gimple_stmt (stderr, SSA_NAME_DEF_STMT (op),
1098 bitmap_set_bit (names_defined_in_bb, SSA_NAME_VERSION (op));
1102 bitmap_clear (names_defined_in_bb);
1105 free (definition_block);
1107 /* Restore the dominance information to its prior known state, so
1108 that we do not perturb the compiler's subsequent behavior. */
1109 if (orig_dom_state == DOM_NONE)
1110 free_dominance_info (CDI_DOMINATORS);
1112 set_dom_info_availability (CDI_DOMINATORS, orig_dom_state);
1114 BITMAP_FREE (names_defined_in_bb);
1115 timevar_pop (TV_TREE_SSA_VERIFY);
1119 internal_error ("verify_ssa failed");
1122 /* Return true if the uid in both int tree maps are equal. */
1125 int_tree_map_eq (const void *va, const void *vb)
1127 const struct int_tree_map *a = (const struct int_tree_map *) va;
1128 const struct int_tree_map *b = (const struct int_tree_map *) vb;
1129 return (a->uid == b->uid);
1132 /* Hash a UID in a int_tree_map. */
1135 int_tree_map_hash (const void *item)
1137 return ((const struct int_tree_map *)item)->uid;
1140 /* Return true if the DECL_UID in both trees are equal. */
1143 uid_decl_map_eq (const void *va, const void *vb)
1145 const_tree a = (const_tree) va;
1146 const_tree b = (const_tree) vb;
1147 return (a->decl_minimal.uid == b->decl_minimal.uid);
1150 /* Hash a tree in a uid_decl_map. */
1153 uid_decl_map_hash (const void *item)
1155 return ((const_tree)item)->decl_minimal.uid;
1158 /* Return true if the DECL_UID in both trees are equal. */
1161 uid_ssaname_map_eq (const void *va, const void *vb)
1163 const_tree a = (const_tree) va;
1164 const_tree b = (const_tree) vb;
1165 return (a->ssa_name.var->decl_minimal.uid == b->ssa_name.var->decl_minimal.uid);
1168 /* Hash a tree in a uid_decl_map. */
1171 uid_ssaname_map_hash (const void *item)
1173 return ((const_tree)item)->ssa_name.var->decl_minimal.uid;
1177 /* Initialize global DFA and SSA structures. */
1180 init_tree_ssa (struct function *fn)
1182 fn->gimple_df = ggc_alloc_cleared_gimple_df ();
1183 fn->gimple_df->referenced_vars = htab_create_ggc (20, uid_decl_map_hash,
1184 uid_decl_map_eq, NULL);
1185 fn->gimple_df->default_defs = htab_create_ggc (20, uid_ssaname_map_hash,
1186 uid_ssaname_map_eq, NULL);
1187 pt_solution_reset (&fn->gimple_df->escaped);
1188 init_ssanames (fn, 0);
1193 /* Deallocate memory associated with SSA data structures for FNDECL. */
1196 delete_tree_ssa (void)
1198 referenced_var_iterator rvi;
1201 /* Remove annotations from every referenced local variable. */
1202 FOR_EACH_REFERENCED_VAR (cfun, var, rvi)
1204 if (is_global_var (var))
1208 ggc_free (var_ann (var));
1209 *DECL_VAR_ANN_PTR (var) = NULL;
1212 htab_delete (gimple_referenced_vars (cfun));
1213 cfun->gimple_df->referenced_vars = NULL;
1218 /* We no longer maintain the SSA operand cache at this point. */
1219 if (ssa_operands_active ())
1220 fini_ssa_operands ();
1222 delete_alias_heapvars ();
1224 htab_delete (cfun->gimple_df->default_defs);
1225 cfun->gimple_df->default_defs = NULL;
1226 pt_solution_reset (&cfun->gimple_df->escaped);
1227 if (cfun->gimple_df->decls_to_pointers != NULL)
1228 pointer_map_destroy (cfun->gimple_df->decls_to_pointers);
1229 cfun->gimple_df->decls_to_pointers = NULL;
1230 cfun->gimple_df->modified_noreturn_calls = NULL;
1231 cfun->gimple_df = NULL;
1233 /* We no longer need the edge variable maps. */
1234 redirect_edge_var_map_destroy ();
1237 /* Return true if the conversion from INNER_TYPE to OUTER_TYPE is a
1238 useless type conversion, otherwise return false.
1240 This function implicitly defines the middle-end type system. With
1241 the notion of 'a < b' meaning that useless_type_conversion_p (a, b)
1242 holds and 'a > b' meaning that useless_type_conversion_p (b, a) holds,
1243 the following invariants shall be fulfilled:
1245 1) useless_type_conversion_p is transitive.
1246 If a < b and b < c then a < c.
1248 2) useless_type_conversion_p is not symmetric.
1249 From a < b does not follow a > b.
1251 3) Types define the available set of operations applicable to values.
1252 A type conversion is useless if the operations for the target type
1253 is a subset of the operations for the source type. For example
1254 casts to void* are useless, casts from void* are not (void* can't
1255 be dereferenced or offsetted, but copied, hence its set of operations
1256 is a strict subset of that of all other data pointer types). Casts
1257 to const T* are useless (can't be written to), casts from const T*
1261 useless_type_conversion_p (tree outer_type, tree inner_type)
1263 /* Do the following before stripping toplevel qualifiers. */
1264 if (POINTER_TYPE_P (inner_type)
1265 && POINTER_TYPE_P (outer_type))
1267 /* Do not lose casts between pointers to different address spaces. */
1268 if (TYPE_ADDR_SPACE (TREE_TYPE (outer_type))
1269 != TYPE_ADDR_SPACE (TREE_TYPE (inner_type)))
1272 /* Do not lose casts to restrict qualified pointers. */
1273 if ((TYPE_RESTRICT (outer_type)
1274 != TYPE_RESTRICT (inner_type))
1275 && TYPE_RESTRICT (outer_type))
1278 /* If the outer type is (void *) or a pointer to an incomplete
1279 record type or a pointer to an unprototyped function,
1280 then the conversion is not necessary. */
1281 if (VOID_TYPE_P (TREE_TYPE (outer_type))
1282 || ((TREE_CODE (TREE_TYPE (outer_type)) == FUNCTION_TYPE
1283 || TREE_CODE (TREE_TYPE (outer_type)) == METHOD_TYPE)
1284 && (TREE_CODE (TREE_TYPE (outer_type))
1285 == TREE_CODE (TREE_TYPE (inner_type)))
1286 && !prototype_p (TREE_TYPE (outer_type))
1287 && useless_type_conversion_p (TREE_TYPE (TREE_TYPE (outer_type)),
1288 TREE_TYPE (TREE_TYPE (inner_type)))))
1292 /* From now on qualifiers on value types do not matter. */
1293 inner_type = TYPE_MAIN_VARIANT (inner_type);
1294 outer_type = TYPE_MAIN_VARIANT (outer_type);
1296 if (inner_type == outer_type)
1299 /* If we know the canonical types, compare them. */
1300 if (TYPE_CANONICAL (inner_type)
1301 && TYPE_CANONICAL (inner_type) == TYPE_CANONICAL (outer_type))
1304 /* Changes in machine mode are never useless conversions unless we
1305 deal with aggregate types in which case we defer to later checks. */
1306 if (TYPE_MODE (inner_type) != TYPE_MODE (outer_type)
1307 && !AGGREGATE_TYPE_P (inner_type))
1310 /* If both the inner and outer types are integral types, then the
1311 conversion is not necessary if they have the same mode and
1312 signedness and precision, and both or neither are boolean. */
1313 if (INTEGRAL_TYPE_P (inner_type)
1314 && INTEGRAL_TYPE_P (outer_type))
1316 /* Preserve changes in signedness or precision. */
1317 if (TYPE_UNSIGNED (inner_type) != TYPE_UNSIGNED (outer_type)
1318 || TYPE_PRECISION (inner_type) != TYPE_PRECISION (outer_type))
1321 /* We don't need to preserve changes in the types minimum or
1322 maximum value in general as these do not generate code
1323 unless the types precisions are different. */
1327 /* Scalar floating point types with the same mode are compatible. */
1328 else if (SCALAR_FLOAT_TYPE_P (inner_type)
1329 && SCALAR_FLOAT_TYPE_P (outer_type))
1332 /* Fixed point types with the same mode are compatible. */
1333 else if (FIXED_POINT_TYPE_P (inner_type)
1334 && FIXED_POINT_TYPE_P (outer_type))
1337 /* We need to take special care recursing to pointed-to types. */
1338 else if (POINTER_TYPE_P (inner_type)
1339 && POINTER_TYPE_P (outer_type))
1341 /* Do not lose casts to function pointer types. */
1342 if ((TREE_CODE (TREE_TYPE (outer_type)) == FUNCTION_TYPE
1343 || TREE_CODE (TREE_TYPE (outer_type)) == METHOD_TYPE)
1344 && !useless_type_conversion_p (TREE_TYPE (outer_type),
1345 TREE_TYPE (inner_type)))
1348 /* We do not care for const qualification of the pointed-to types
1349 as const qualification has no semantic value to the middle-end. */
1351 /* Otherwise pointers/references are equivalent. */
1355 /* Recurse for complex types. */
1356 else if (TREE_CODE (inner_type) == COMPLEX_TYPE
1357 && TREE_CODE (outer_type) == COMPLEX_TYPE)
1358 return useless_type_conversion_p (TREE_TYPE (outer_type),
1359 TREE_TYPE (inner_type));
1361 /* Recurse for vector types with the same number of subparts. */
1362 else if (TREE_CODE (inner_type) == VECTOR_TYPE
1363 && TREE_CODE (outer_type) == VECTOR_TYPE
1364 && TYPE_PRECISION (inner_type) == TYPE_PRECISION (outer_type))
1365 return useless_type_conversion_p (TREE_TYPE (outer_type),
1366 TREE_TYPE (inner_type));
1368 else if (TREE_CODE (inner_type) == ARRAY_TYPE
1369 && TREE_CODE (outer_type) == ARRAY_TYPE)
1371 /* Preserve string attributes. */
1372 if (TYPE_STRING_FLAG (inner_type) != TYPE_STRING_FLAG (outer_type))
1375 /* Conversions from array types with unknown extent to
1376 array types with known extent are not useless. */
1377 if (!TYPE_DOMAIN (inner_type)
1378 && TYPE_DOMAIN (outer_type))
1381 /* Nor are conversions from array types with non-constant size to
1382 array types with constant size or to different size. */
1383 if (TYPE_SIZE (outer_type)
1384 && TREE_CODE (TYPE_SIZE (outer_type)) == INTEGER_CST
1385 && (!TYPE_SIZE (inner_type)
1386 || TREE_CODE (TYPE_SIZE (inner_type)) != INTEGER_CST
1387 || !tree_int_cst_equal (TYPE_SIZE (outer_type),
1388 TYPE_SIZE (inner_type))))
1391 /* Check conversions between arrays with partially known extents.
1392 If the array min/max values are constant they have to match.
1393 Otherwise allow conversions to unknown and variable extents.
1394 In particular this declares conversions that may change the
1395 mode to BLKmode as useless. */
1396 if (TYPE_DOMAIN (inner_type)
1397 && TYPE_DOMAIN (outer_type)
1398 && TYPE_DOMAIN (inner_type) != TYPE_DOMAIN (outer_type))
1400 tree inner_min = TYPE_MIN_VALUE (TYPE_DOMAIN (inner_type));
1401 tree outer_min = TYPE_MIN_VALUE (TYPE_DOMAIN (outer_type));
1402 tree inner_max = TYPE_MAX_VALUE (TYPE_DOMAIN (inner_type));
1403 tree outer_max = TYPE_MAX_VALUE (TYPE_DOMAIN (outer_type));
1405 /* After gimplification a variable min/max value carries no
1406 additional information compared to a NULL value. All that
1407 matters has been lowered to be part of the IL. */
1408 if (inner_min && TREE_CODE (inner_min) != INTEGER_CST)
1409 inner_min = NULL_TREE;
1410 if (outer_min && TREE_CODE (outer_min) != INTEGER_CST)
1411 outer_min = NULL_TREE;
1412 if (inner_max && TREE_CODE (inner_max) != INTEGER_CST)
1413 inner_max = NULL_TREE;
1414 if (outer_max && TREE_CODE (outer_max) != INTEGER_CST)
1415 outer_max = NULL_TREE;
1417 /* Conversions NULL / variable <- cst are useless, but not
1418 the other way around. */
1421 || !tree_int_cst_equal (inner_min, outer_min)))
1425 || !tree_int_cst_equal (inner_max, outer_max)))
1429 /* Recurse on the element check. */
1430 return useless_type_conversion_p (TREE_TYPE (outer_type),
1431 TREE_TYPE (inner_type));
1434 else if ((TREE_CODE (inner_type) == FUNCTION_TYPE
1435 || TREE_CODE (inner_type) == METHOD_TYPE)
1436 && TREE_CODE (inner_type) == TREE_CODE (outer_type))
1438 tree outer_parm, inner_parm;
1440 /* If the return types are not compatible bail out. */
1441 if (!useless_type_conversion_p (TREE_TYPE (outer_type),
1442 TREE_TYPE (inner_type)))
1445 /* Method types should belong to a compatible base class. */
1446 if (TREE_CODE (inner_type) == METHOD_TYPE
1447 && !useless_type_conversion_p (TYPE_METHOD_BASETYPE (outer_type),
1448 TYPE_METHOD_BASETYPE (inner_type)))
1451 /* A conversion to an unprototyped argument list is ok. */
1452 if (!prototype_p (outer_type))
1455 /* If the unqualified argument types are compatible the conversion
1457 if (TYPE_ARG_TYPES (outer_type) == TYPE_ARG_TYPES (inner_type))
1460 for (outer_parm = TYPE_ARG_TYPES (outer_type),
1461 inner_parm = TYPE_ARG_TYPES (inner_type);
1462 outer_parm && inner_parm;
1463 outer_parm = TREE_CHAIN (outer_parm),
1464 inner_parm = TREE_CHAIN (inner_parm))
1465 if (!useless_type_conversion_p
1466 (TYPE_MAIN_VARIANT (TREE_VALUE (outer_parm)),
1467 TYPE_MAIN_VARIANT (TREE_VALUE (inner_parm))))
1470 /* If there is a mismatch in the number of arguments the functions
1471 are not compatible. */
1472 if (outer_parm || inner_parm)
1475 /* Defer to the target if necessary. */
1476 if (TYPE_ATTRIBUTES (inner_type) || TYPE_ATTRIBUTES (outer_type))
1477 return targetm.comp_type_attributes (outer_type, inner_type) != 0;
1482 /* For aggregates we rely on TYPE_CANONICAL exclusively and require
1483 explicit conversions for types involving to be structurally
1485 else if (AGGREGATE_TYPE_P (inner_type)
1486 && TREE_CODE (inner_type) == TREE_CODE (outer_type))
1492 /* Return true if a conversion from either type of TYPE1 and TYPE2
1493 to the other is not required. Otherwise return false. */
1496 types_compatible_p (tree type1, tree type2)
1498 return (type1 == type2
1499 || (useless_type_conversion_p (type1, type2)
1500 && useless_type_conversion_p (type2, type1)));
1503 /* Return true if EXPR is a useless type conversion, otherwise return
1507 tree_ssa_useless_type_conversion (tree expr)
1509 /* If we have an assignment that merely uses a NOP_EXPR to change
1510 the top of the RHS to the type of the LHS and the type conversion
1511 is "safe", then strip away the type conversion so that we can
1512 enter LHS = RHS into the const_and_copies table. */
1513 if (CONVERT_EXPR_P (expr)
1514 || TREE_CODE (expr) == VIEW_CONVERT_EXPR
1515 || TREE_CODE (expr) == NON_LVALUE_EXPR)
1516 return useless_type_conversion_p
1518 TREE_TYPE (TREE_OPERAND (expr, 0)));
1523 /* Strip conversions from EXP according to
1524 tree_ssa_useless_type_conversion and return the resulting
1528 tree_ssa_strip_useless_type_conversions (tree exp)
1530 while (tree_ssa_useless_type_conversion (exp))
1531 exp = TREE_OPERAND (exp, 0);
1536 /* Internal helper for walk_use_def_chains. VAR, FN and DATA are as
1537 described in walk_use_def_chains.
1539 VISITED is a pointer set used to mark visited SSA_NAMEs to avoid
1540 infinite loops. We used to have a bitmap for this to just mark
1541 SSA versions we had visited. But non-sparse bitmaps are way too
1542 expensive, while sparse bitmaps may cause quadratic behavior.
1544 IS_DFS is true if the caller wants to perform a depth-first search
1545 when visiting PHI nodes. A DFS will visit each PHI argument and
1546 call FN after each one. Otherwise, all the arguments are
1547 visited first and then FN is called with each of the visited
1548 arguments in a separate pass. */
1551 walk_use_def_chains_1 (tree var, walk_use_def_chains_fn fn, void *data,
1552 struct pointer_set_t *visited, bool is_dfs)
1556 if (pointer_set_insert (visited, var))
1559 def_stmt = SSA_NAME_DEF_STMT (var);
1561 if (gimple_code (def_stmt) != GIMPLE_PHI)
1563 /* If we reached the end of the use-def chain, call FN. */
1564 return fn (var, def_stmt, data);
1570 /* When doing a breadth-first search, call FN before following the
1571 use-def links for each argument. */
1573 for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
1574 if (fn (gimple_phi_arg_def (def_stmt, i), def_stmt, data))
1577 /* Follow use-def links out of each PHI argument. */
1578 for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
1580 tree arg = gimple_phi_arg_def (def_stmt, i);
1582 /* ARG may be NULL for newly introduced PHI nodes. */
1584 && TREE_CODE (arg) == SSA_NAME
1585 && walk_use_def_chains_1 (arg, fn, data, visited, is_dfs))
1589 /* When doing a depth-first search, call FN after following the
1590 use-def links for each argument. */
1592 for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
1593 if (fn (gimple_phi_arg_def (def_stmt, i), def_stmt, data))
1602 /* Walk use-def chains starting at the SSA variable VAR. Call
1603 function FN at each reaching definition found. FN takes three
1604 arguments: VAR, its defining statement (DEF_STMT) and a generic
1605 pointer to whatever state information that FN may want to maintain
1606 (DATA). FN is able to stop the walk by returning true, otherwise
1607 in order to continue the walk, FN should return false.
1609 Note, that if DEF_STMT is a PHI node, the semantics are slightly
1610 different. The first argument to FN is no longer the original
1611 variable VAR, but the PHI argument currently being examined. If FN
1612 wants to get at VAR, it should call PHI_RESULT (PHI).
1614 If IS_DFS is true, this function will:
1616 1- walk the use-def chains for all the PHI arguments, and,
1617 2- call (*FN) (ARG, PHI, DATA) on all the PHI arguments.
1619 If IS_DFS is false, the two steps above are done in reverse order
1620 (i.e., a breadth-first search). */
1623 walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data,
1628 gcc_assert (TREE_CODE (var) == SSA_NAME);
1630 def_stmt = SSA_NAME_DEF_STMT (var);
1632 /* We only need to recurse if the reaching definition comes from a PHI
1634 if (gimple_code (def_stmt) != GIMPLE_PHI)
1635 (*fn) (var, def_stmt, data);
1638 struct pointer_set_t *visited = pointer_set_create ();
1639 walk_use_def_chains_1 (var, fn, data, visited, is_dfs);
1640 pointer_set_destroy (visited);
1645 /* Emit warnings for uninitialized variables. This is done in two passes.
1647 The first pass notices real uses of SSA names with undefined values.
1648 Such uses are unconditionally uninitialized, and we can be certain that
1649 such a use is a mistake. This pass is run before most optimizations,
1650 so that we catch as many as we can.
1652 The second pass follows PHI nodes to find uses that are potentially
1653 uninitialized. In this case we can't necessarily prove that the use
1654 is really uninitialized. This pass is run after most optimizations,
1655 so that we thread as many jumps and possible, and delete as much dead
1656 code as possible, in order to reduce false positives. We also look
1657 again for plain uninitialized variables, since optimization may have
1658 changed conditionally uninitialized to unconditionally uninitialized. */
1660 /* Emit a warning for T, an SSA_NAME, being uninitialized. The exact
1661 warning text is in MSGID and LOCUS may contain a location or be null. */
1664 warn_uninit (tree t, const char *gmsgid, void *data)
1666 tree var = SSA_NAME_VAR (t);
1667 gimple context = (gimple) data;
1668 location_t location;
1669 expanded_location xloc, floc;
1671 if (!ssa_undefined_value_p (t))
1674 /* TREE_NO_WARNING either means we already warned, or the front end
1675 wishes to suppress the warning. */
1676 if (TREE_NO_WARNING (var))
1679 /* Do not warn if it can be initialized outside this module. */
1680 if (is_global_var (var))
1683 location = (context != NULL && gimple_has_location (context))
1684 ? gimple_location (context)
1685 : DECL_SOURCE_LOCATION (var);
1686 xloc = expand_location (location);
1687 floc = expand_location (DECL_SOURCE_LOCATION (cfun->decl));
1688 if (warning_at (location, OPT_Wuninitialized, gmsgid, var))
1690 TREE_NO_WARNING (var) = 1;
1692 if (location == DECL_SOURCE_LOCATION (var))
1694 if (xloc.file != floc.file
1695 || xloc.line < floc.line
1696 || xloc.line > LOCATION_LINE (cfun->function_end_locus))
1697 inform (DECL_SOURCE_LOCATION (var), "%qD was declared here", var);
1703 bool always_executed;
1704 bool warn_possibly_uninitialized;
1707 /* Called via walk_tree, look for SSA_NAMEs that have empty definitions
1708 and warn about them. */
1711 warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data_)
1713 struct walk_stmt_info *wi = (struct walk_stmt_info *) data_;
1714 struct walk_data *data = (struct walk_data *) wi->info;
1717 /* We do not care about LHS. */
1720 /* Except for operands of dereferences. */
1721 if (!INDIRECT_REF_P (t)
1722 && TREE_CODE (t) != MEM_REF)
1724 t = TREE_OPERAND (t, 0);
1727 switch (TREE_CODE (t))
1730 /* Taking the address of an uninitialized variable does not
1731 count as using it. */
1737 /* A VAR_DECL in the RHS of a gimple statement may mean that
1738 this variable is loaded from memory. */
1742 /* If there is not gimple stmt,
1743 or alias information has not been computed,
1744 then we cannot check VUSE ops. */
1745 if (data->stmt == NULL)
1748 /* If the load happens as part of a call do not warn about it. */
1749 if (is_gimple_call (data->stmt))
1752 vuse = gimple_vuse_op (data->stmt);
1753 if (vuse == NULL_USE_OPERAND_P)
1756 op = USE_FROM_PTR (vuse);
1757 if (t != SSA_NAME_VAR (op)
1758 || !SSA_NAME_IS_DEFAULT_DEF (op))
1760 /* If this is a VUSE of t and it is the default definition,
1761 then warn about op. */
1763 /* Fall through into SSA_NAME. */
1767 /* We only do data flow with SSA_NAMEs, so that's all we
1769 if (data->always_executed)
1770 warn_uninit (t, "%qD is used uninitialized in this function",
1772 else if (data->warn_possibly_uninitialized)
1773 warn_uninit (t, "%qD may be used uninitialized in this function",
1780 /* The total store transformation performed during gimplification
1781 creates uninitialized variable uses. If all is well, these will
1782 be optimized away, so don't warn now. */
1783 if (TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME)
1788 if (IS_TYPE_OR_DECL_P (t))
1797 warn_uninitialized_vars (bool warn_possibly_uninitialized)
1799 gimple_stmt_iterator gsi;
1801 struct walk_data data;
1803 data.warn_possibly_uninitialized = warn_possibly_uninitialized;
1808 data.always_executed = dominated_by_p (CDI_POST_DOMINATORS,
1809 single_succ (ENTRY_BLOCK_PTR), bb);
1810 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1812 struct walk_stmt_info wi;
1813 data.stmt = gsi_stmt (gsi);
1814 if (is_gimple_debug (data.stmt))
1816 memset (&wi, 0, sizeof (wi));
1818 walk_gimple_op (gsi_stmt (gsi), warn_uninitialized_var, &wi);
1826 execute_early_warn_uninitialized (void)
1828 /* Currently, this pass runs always but
1829 execute_late_warn_uninitialized only runs with optimization. With
1830 optimization we want to warn about possible uninitialized as late
1831 as possible, thus don't do it here. However, without
1832 optimization we need to warn here about "may be uninitialized".
1834 calculate_dominance_info (CDI_POST_DOMINATORS);
1836 warn_uninitialized_vars (/*warn_possibly_uninitialized=*/!optimize);
1838 /* Post-dominator information can not be reliably updated. Free it
1841 free_dominance_info (CDI_POST_DOMINATORS);
1846 gate_warn_uninitialized (void)
1848 return warn_uninitialized != 0;
1851 struct gimple_opt_pass pass_early_warn_uninitialized =
1855 "*early_warn_uninitialized", /* name */
1856 gate_warn_uninitialized, /* gate */
1857 execute_early_warn_uninitialized, /* execute */
1860 0, /* static_pass_number */
1861 TV_TREE_UNINIT, /* tv_id */
1862 PROP_ssa, /* properties_required */
1863 0, /* properties_provided */
1864 0, /* properties_destroyed */
1865 0, /* todo_flags_start */
1866 0 /* todo_flags_finish */
1871 /* If necessary, rewrite the base of the reference tree *TP from
1872 a MEM_REF to a plain or converted symbol. */
1875 maybe_rewrite_mem_ref_base (tree *tp)
1879 while (handled_component_p (*tp))
1880 tp = &TREE_OPERAND (*tp, 0);
1881 if (TREE_CODE (*tp) == MEM_REF
1882 && TREE_CODE (TREE_OPERAND (*tp, 0)) == ADDR_EXPR
1883 && integer_zerop (TREE_OPERAND (*tp, 1))
1884 && (sym = TREE_OPERAND (TREE_OPERAND (*tp, 0), 0))
1886 && !TREE_ADDRESSABLE (sym)
1887 && symbol_marked_for_renaming (sym))
1889 if (!useless_type_conversion_p (TREE_TYPE (*tp),
1891 *tp = build1 (VIEW_CONVERT_EXPR,
1892 TREE_TYPE (*tp), sym);
1898 /* For a tree REF return its base if it is the base of a MEM_REF
1899 that cannot be rewritten into SSA form. Otherwise return NULL_TREE. */
1902 non_rewritable_mem_ref_base (tree ref)
1906 /* A plain decl does not need it set. */
1910 while (handled_component_p (base))
1911 base = TREE_OPERAND (base, 0);
1913 /* But watch out for MEM_REFs we cannot lower to a
1914 VIEW_CONVERT_EXPR. */
1915 if (TREE_CODE (base) == MEM_REF
1916 && TREE_CODE (TREE_OPERAND (base, 0)) == ADDR_EXPR)
1918 tree decl = TREE_OPERAND (TREE_OPERAND (base, 0), 0);
1920 && (!integer_zerop (TREE_OPERAND (base, 1))
1921 || (DECL_SIZE (decl)
1922 != TYPE_SIZE (TREE_TYPE (base)))
1923 || TREE_THIS_VOLATILE (decl) != TREE_THIS_VOLATILE (base)))
1930 /* For an lvalue tree LHS return true if it cannot be rewritten into SSA form.
1931 Otherwise return true. */
1934 non_rewritable_lvalue_p (tree lhs)
1936 /* A plain decl is always rewritable. */
1940 /* A decl that is wrapped inside a MEM-REF that covers
1941 it full is also rewritable.
1942 ??? The following could be relaxed allowing component
1943 references that do not change the access size. */
1944 if (TREE_CODE (lhs) == MEM_REF
1945 && TREE_CODE (TREE_OPERAND (lhs, 0)) == ADDR_EXPR
1946 && integer_zerop (TREE_OPERAND (lhs, 1)))
1948 tree decl = TREE_OPERAND (TREE_OPERAND (lhs, 0), 0);
1950 && DECL_SIZE (decl) == TYPE_SIZE (TREE_TYPE (lhs))
1951 && (TREE_THIS_VOLATILE (decl) == TREE_THIS_VOLATILE (lhs)))
1958 /* When possible, clear TREE_ADDRESSABLE bit or set DECL_GIMPLE_REG_P bit and
1959 mark the variable VAR for conversion into SSA. Return true when updating
1960 stmts is required. */
1963 maybe_optimize_var (tree var, bitmap addresses_taken, bitmap not_reg_needs)
1965 bool update_vops = false;
1967 /* Global Variables, result decls cannot be changed. */
1968 if (is_global_var (var)
1969 || TREE_CODE (var) == RESULT_DECL
1970 || bitmap_bit_p (addresses_taken, DECL_UID (var)))
1973 /* If the variable is not in the list of referenced vars then we
1974 do not need to touch it nor can we rename it. */
1975 if (!referenced_var_lookup (cfun, DECL_UID (var)))
1978 if (TREE_ADDRESSABLE (var)
1979 /* Do not change TREE_ADDRESSABLE if we need to preserve var as
1980 a non-register. Otherwise we are confused and forget to
1981 add virtual operands for it. */
1982 && (!is_gimple_reg_type (TREE_TYPE (var))
1983 || !bitmap_bit_p (not_reg_needs, DECL_UID (var))))
1985 TREE_ADDRESSABLE (var) = 0;
1986 if (is_gimple_reg (var))
1987 mark_sym_for_renaming (var);
1991 fprintf (dump_file, "No longer having address taken: ");
1992 print_generic_expr (dump_file, var, 0);
1993 fprintf (dump_file, "\n");
1997 if (!DECL_GIMPLE_REG_P (var)
1998 && !bitmap_bit_p (not_reg_needs, DECL_UID (var))
1999 && (TREE_CODE (TREE_TYPE (var)) == COMPLEX_TYPE
2000 || TREE_CODE (TREE_TYPE (var)) == VECTOR_TYPE)
2001 && !TREE_THIS_VOLATILE (var)
2002 && (TREE_CODE (var) != VAR_DECL || !DECL_HARD_REGISTER (var)))
2004 DECL_GIMPLE_REG_P (var) = 1;
2005 mark_sym_for_renaming (var);
2009 fprintf (dump_file, "Now a gimple register: ");
2010 print_generic_expr (dump_file, var, 0);
2011 fprintf (dump_file, "\n");
2018 /* Compute TREE_ADDRESSABLE and DECL_GIMPLE_REG_P for local variables. */
2021 execute_update_addresses_taken (void)
2023 gimple_stmt_iterator gsi;
2025 bitmap addresses_taken = BITMAP_ALLOC (NULL);
2026 bitmap not_reg_needs = BITMAP_ALLOC (NULL);
2027 bool update_vops = false;
2031 timevar_push (TV_ADDRESS_TAKEN);
2033 /* Collect into ADDRESSES_TAKEN all variables whose address is taken within
2034 the function body. */
2037 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
2039 gimple stmt = gsi_stmt (gsi);
2040 enum gimple_code code = gimple_code (stmt);
2043 /* Note all addresses taken by the stmt. */
2044 gimple_ior_addresses_taken (addresses_taken, stmt);
2046 /* If we have a call or an assignment, see if the lhs contains
2047 a local decl that requires not to be a gimple register. */
2048 if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL)
2050 tree lhs = gimple_get_lhs (stmt);
2052 && TREE_CODE (lhs) != SSA_NAME
2053 && non_rewritable_lvalue_p (lhs))
2055 decl = get_base_address (lhs);
2057 bitmap_set_bit (not_reg_needs, DECL_UID (decl));
2061 if (gimple_assign_single_p (stmt))
2063 tree rhs = gimple_assign_rhs1 (stmt);
2064 if ((decl = non_rewritable_mem_ref_base (rhs)))
2065 bitmap_set_bit (not_reg_needs, DECL_UID (decl));
2068 else if (code == GIMPLE_CALL)
2070 for (i = 0; i < gimple_call_num_args (stmt); ++i)
2072 tree arg = gimple_call_arg (stmt, i);
2073 if ((decl = non_rewritable_mem_ref_base (arg)))
2074 bitmap_set_bit (not_reg_needs, DECL_UID (decl));
2078 else if (code == GIMPLE_ASM)
2080 for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
2082 tree link = gimple_asm_output_op (stmt, i);
2083 tree lhs = TREE_VALUE (link);
2084 if (TREE_CODE (lhs) != SSA_NAME)
2086 decl = get_base_address (lhs);
2088 && (non_rewritable_lvalue_p (lhs)
2089 /* We cannot move required conversions from
2090 the lhs to the rhs in asm statements, so
2091 require we do not need any. */
2092 || !useless_type_conversion_p
2093 (TREE_TYPE (lhs), TREE_TYPE (decl))))
2094 bitmap_set_bit (not_reg_needs, DECL_UID (decl));
2097 for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
2099 tree link = gimple_asm_input_op (stmt, i);
2100 if ((decl = non_rewritable_mem_ref_base (TREE_VALUE (link))))
2101 bitmap_set_bit (not_reg_needs, DECL_UID (decl));
2106 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
2109 gimple phi = gsi_stmt (gsi);
2111 for (i = 0; i < gimple_phi_num_args (phi); i++)
2113 tree op = PHI_ARG_DEF (phi, i), var;
2114 if (TREE_CODE (op) == ADDR_EXPR
2115 && (var = get_base_address (TREE_OPERAND (op, 0))) != NULL
2117 bitmap_set_bit (addresses_taken, DECL_UID (var));
2122 /* We cannot iterate over all referenced vars because that can contain
2123 unused vars from BLOCK trees, which causes code generation differences
2125 for (var = DECL_ARGUMENTS (cfun->decl); var; var = DECL_CHAIN (var))
2126 update_vops |= maybe_optimize_var (var, addresses_taken, not_reg_needs);
2128 FOR_EACH_VEC_ELT (tree, cfun->local_decls, i, var)
2129 update_vops |= maybe_optimize_var (var, addresses_taken, not_reg_needs);
2131 /* Operand caches need to be recomputed for operands referencing the updated
2136 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
2138 gimple stmt = gsi_stmt (gsi);
2140 /* Re-write TARGET_MEM_REFs of symbols we want to
2141 rewrite into SSA form. */
2142 if (gimple_assign_single_p (stmt))
2144 tree lhs = gimple_assign_lhs (stmt);
2145 tree rhs, *rhsp = gimple_assign_rhs1_ptr (stmt);
2148 /* We shouldn't have any fancy wrapping of
2149 component-refs on the LHS, but look through
2150 VIEW_CONVERT_EXPRs as that is easy. */
2151 while (TREE_CODE (lhs) == VIEW_CONVERT_EXPR)
2152 lhs = TREE_OPERAND (lhs, 0);
2153 if (TREE_CODE (lhs) == MEM_REF
2154 && TREE_CODE (TREE_OPERAND (lhs, 0)) == ADDR_EXPR
2155 && integer_zerop (TREE_OPERAND (lhs, 1))
2156 && (sym = TREE_OPERAND (TREE_OPERAND (lhs, 0), 0))
2158 && !TREE_ADDRESSABLE (sym)
2159 && symbol_marked_for_renaming (sym))
2162 lhs = gimple_assign_lhs (stmt);
2164 /* Rewrite the RHS and make sure the resulting assignment
2165 is validly typed. */
2166 maybe_rewrite_mem_ref_base (rhsp);
2167 rhs = gimple_assign_rhs1 (stmt);
2168 if (gimple_assign_lhs (stmt) != lhs
2169 && !useless_type_conversion_p (TREE_TYPE (lhs),
2171 rhs = fold_build1 (VIEW_CONVERT_EXPR,
2172 TREE_TYPE (lhs), rhs);
2174 if (gimple_assign_lhs (stmt) != lhs)
2175 gimple_assign_set_lhs (stmt, lhs);
2177 if (gimple_assign_rhs1 (stmt) != rhs)
2179 gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
2180 gimple_assign_set_rhs_from_tree (&gsi, rhs);
2184 else if (gimple_code (stmt) == GIMPLE_CALL)
2187 for (i = 0; i < gimple_call_num_args (stmt); ++i)
2189 tree *argp = gimple_call_arg_ptr (stmt, i);
2190 maybe_rewrite_mem_ref_base (argp);
2194 else if (gimple_code (stmt) == GIMPLE_ASM)
2197 for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
2199 tree link = gimple_asm_output_op (stmt, i);
2200 maybe_rewrite_mem_ref_base (&TREE_VALUE (link));
2202 for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
2204 tree link = gimple_asm_input_op (stmt, i);
2205 maybe_rewrite_mem_ref_base (&TREE_VALUE (link));
2209 else if (gimple_debug_bind_p (stmt)
2210 && gimple_debug_bind_has_value_p (stmt))
2212 tree *valuep = gimple_debug_bind_get_value_ptr (stmt);
2214 maybe_rewrite_mem_ref_base (valuep);
2215 decl = non_rewritable_mem_ref_base (*valuep);
2216 if (decl && symbol_marked_for_renaming (decl))
2217 gimple_debug_bind_reset_value (stmt);
2220 if (gimple_references_memory_p (stmt)
2221 || is_gimple_debug (stmt))
2225 /* Update SSA form here, we are called as non-pass as well. */
2226 if (number_of_loops () > 1 && loops_state_satisfies_p (LOOP_CLOSED_SSA))
2227 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
2229 update_ssa (TODO_update_ssa);
2232 BITMAP_FREE (not_reg_needs);
2233 BITMAP_FREE (addresses_taken);
2234 timevar_pop (TV_ADDRESS_TAKEN);
2237 struct gimple_opt_pass pass_update_address_taken =
2241 "addressables", /* name */
2246 0, /* static_pass_number */
2247 TV_ADDRESS_TAKEN, /* tv_id */
2248 PROP_ssa, /* properties_required */
2249 0, /* properties_provided */
2250 0, /* properties_destroyed */
2251 0, /* todo_flags_start */
2252 TODO_update_address_taken
2253 | TODO_dump_func /* todo_flags_finish */