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"
33 #include "gimple-pretty-print.h"
35 #include "pointer-set.h"
36 #include "tree-flow.h"
38 #include "tree-inline.h"
40 #include "tree-pass.h"
41 #include "diagnostic-core.h"
44 /* Pointer map of variable mappings, keyed by edge. */
45 static struct pointer_map_t
*edge_var_maps
;
48 /* Add a mapping with PHI RESULT and PHI DEF associated with edge E. */
51 redirect_edge_var_map_add (edge e
, tree result
, tree def
, source_location locus
)
54 edge_var_map_vector
*head
;
55 edge_var_map new_node
;
57 if (edge_var_maps
== NULL
)
58 edge_var_maps
= pointer_map_create ();
60 slot
= pointer_map_insert (edge_var_maps
, e
);
61 head
= (edge_var_map_vector
*) *slot
;
64 head
= new edge_var_map_vector
;
69 new_node
.result
= result
;
70 new_node
.locus
= locus
;
72 head
->safe_push (new_node
);
76 /* Clear the var mappings in edge E. */
79 redirect_edge_var_map_clear (edge e
)
82 edge_var_map_vector
*head
;
87 slot
= pointer_map_contains (edge_var_maps
, e
);
91 head
= (edge_var_map_vector
*) *slot
;
98 /* Duplicate the redirected var mappings in OLDE in NEWE.
100 Since we can't remove a mapping, let's just duplicate it. This assumes a
101 pointer_map can have multiple edges mapping to the same var_map (many to
102 one mapping), since we don't remove the previous mappings. */
105 redirect_edge_var_map_dup (edge newe
, edge olde
)
107 void **new_slot
, **old_slot
;
108 edge_var_map_vector
*head
;
113 new_slot
= pointer_map_insert (edge_var_maps
, newe
);
114 old_slot
= pointer_map_contains (edge_var_maps
, olde
);
117 head
= (edge_var_map_vector
*) *old_slot
;
119 edge_var_map_vector
*new_head
= new edge_var_map_vector
;
121 *new_head
= head
->copy ();
123 new_head
->create (5);
124 *new_slot
= new_head
;
128 /* Return the variable mappings for a given edge. If there is none, return
131 edge_var_map_vector
*
132 redirect_edge_var_map_vector (edge e
)
136 /* Hey, what kind of idiot would... you'd be surprised. */
140 slot
= pointer_map_contains (edge_var_maps
, e
);
144 return (edge_var_map_vector
*) *slot
;
147 /* Used by redirect_edge_var_map_destroy to free all memory. */
150 free_var_map_entry (const void *key ATTRIBUTE_UNUSED
,
152 void *data ATTRIBUTE_UNUSED
)
154 edge_var_map_vector
*head
= (edge_var_map_vector
*) *value
;
159 /* Clear the edge variable mappings. */
162 redirect_edge_var_map_destroy (void)
166 pointer_map_traverse (edge_var_maps
, free_var_map_entry
, NULL
);
167 pointer_map_destroy (edge_var_maps
);
168 edge_var_maps
= NULL
;
173 /* Remove the corresponding arguments from the PHI nodes in E's
174 destination block and redirect it to DEST. Return redirected edge.
175 The list of removed arguments is stored in a vector accessed
176 through edge_var_maps. */
179 ssa_redirect_edge (edge e
, basic_block dest
)
181 gimple_stmt_iterator gsi
;
184 redirect_edge_var_map_clear (e
);
186 /* Remove the appropriate PHI arguments in E's destination block. */
187 for (gsi
= gsi_start_phis (e
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
190 source_location locus
;
192 phi
= gsi_stmt (gsi
);
193 def
= gimple_phi_arg_def (phi
, e
->dest_idx
);
194 locus
= gimple_phi_arg_location (phi
, e
->dest_idx
);
196 if (def
== NULL_TREE
)
199 redirect_edge_var_map_add (e
, gimple_phi_result (phi
), def
, locus
);
202 e
= redirect_edge_succ_nodup (e
, dest
);
208 /* Add PHI arguments queued in PENDING_STMT list on edge E to edge
212 flush_pending_stmts (edge e
)
215 edge_var_map_vector
*v
;
218 gimple_stmt_iterator gsi
;
220 v
= redirect_edge_var_map_vector (e
);
224 for (gsi
= gsi_start_phis (e
->dest
), i
= 0;
225 !gsi_end_p (gsi
) && v
->iterate (i
, &vm
);
226 gsi_next (&gsi
), i
++)
230 phi
= gsi_stmt (gsi
);
231 def
= redirect_edge_var_map_def (vm
);
232 add_phi_arg (phi
, def
, e
, redirect_edge_var_map_location (vm
));
235 redirect_edge_var_map_clear (e
);
238 /* Given a tree for an expression for which we might want to emit
239 locations or values in debug information (generally a variable, but
240 we might deal with other kinds of trees in the future), return the
241 tree that should be used as the variable of a DEBUG_BIND STMT or
242 VAR_LOCATION INSN or NOTE. Return NULL if VAR is not to be tracked. */
245 target_for_debug_bind (tree var
)
247 if (!MAY_HAVE_DEBUG_STMTS
)
250 if (TREE_CODE (var
) == SSA_NAME
)
252 var
= SSA_NAME_VAR (var
);
253 if (var
== NULL_TREE
)
257 if ((TREE_CODE (var
) != VAR_DECL
258 || VAR_DECL_IS_VIRTUAL_OPERAND (var
))
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 /* var-tracking only tracks registers. */
269 if (!is_gimple_reg_type (TREE_TYPE (var
)))
275 /* Called via walk_tree, look for SSA_NAMEs that have already been
279 find_released_ssa_name (tree
*tp
, int *walk_subtrees
, void *data_
)
281 struct walk_stmt_info
*wi
= (struct walk_stmt_info
*) data_
;
283 if (wi
&& wi
->is_lhs
)
286 if (TREE_CODE (*tp
) == SSA_NAME
)
288 if (SSA_NAME_IN_FREE_LIST (*tp
))
293 else if (IS_TYPE_OR_DECL_P (*tp
))
299 /* Insert a DEBUG BIND stmt before the DEF of VAR if VAR is referenced
300 by other DEBUG stmts, and replace uses of the DEF with the
301 newly-created debug temp. */
304 insert_debug_temp_for_var_def (gimple_stmt_iterator
*gsi
, tree var
)
306 imm_use_iterator imm_iter
;
309 gimple def_stmt
= NULL
;
313 if (!MAY_HAVE_DEBUG_STMTS
)
316 /* If this name has already been registered for replacement, do nothing
317 as anything that uses this name isn't in SSA form. */
318 if (name_registered_for_update_p (var
))
321 /* Check whether there are debug stmts that reference this variable and,
322 if there are, decide whether we should use a debug temp. */
323 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, var
)
325 stmt
= USE_STMT (use_p
);
327 if (!gimple_debug_bind_p (stmt
))
333 if (gimple_debug_bind_get_value (stmt
) != var
)
335 /* Count this as an additional use, so as to make sure we
336 use a temp unless VAR's definition has a SINGLE_RHS that
347 def_stmt
= gsi_stmt (*gsi
);
349 def_stmt
= SSA_NAME_DEF_STMT (var
);
351 /* If we didn't get an insertion point, and the stmt has already
352 been removed, we won't be able to insert the debug bind stmt, so
353 we'll have to drop debug information. */
354 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
356 value
= degenerate_phi_result (def_stmt
);
357 if (value
&& walk_tree (&value
, find_released_ssa_name
, NULL
, NULL
))
359 /* error_mark_node is what fixup_noreturn_call changes PHI arguments
361 else if (value
== error_mark_node
)
364 else if (is_gimple_assign (def_stmt
))
366 bool no_value
= false;
368 if (!dom_info_available_p (CDI_DOMINATORS
))
370 struct walk_stmt_info wi
;
372 memset (&wi
, 0, sizeof (wi
));
374 /* When removing blocks without following reverse dominance
375 order, we may sometimes encounter SSA_NAMEs that have
376 already been released, referenced in other SSA_DEFs that
377 we're about to release. Consider:
386 If we deleted BB X first, propagating the value of w_2
387 won't do us any good. It's too late to recover their
388 original definition of v_1: when it was deleted, it was
389 only referenced in other DEFs, it couldn't possibly know
390 it should have been retained, and propagating every
391 single DEF just in case it might have to be propagated
392 into a DEBUG STMT would probably be too wasteful.
394 When dominator information is not readily available, we
395 check for and accept some loss of debug information. But
396 if it is available, there's no excuse for us to remove
397 blocks in the wrong order, so we don't even check for
398 dead SSA NAMEs. SSA verification shall catch any
400 if ((!gsi
&& !gimple_bb (def_stmt
))
401 || walk_gimple_op (def_stmt
, find_released_ssa_name
, &wi
))
406 value
= gimple_assign_rhs_to_tree (def_stmt
);
411 /* If there's a single use of VAR, and VAR is the entire debug
412 expression (usecount would have been incremented again
413 otherwise), and the definition involves only constants and
414 SSA names, then we can propagate VALUE into this single use,
417 We can also avoid using a temp if VALUE can be shared and
418 propagated into all uses, without generating expressions that
419 wouldn't be valid gimple RHSs.
421 Other cases that would require unsharing or non-gimple RHSs
422 are deferred to a debug temp, although we could avoid temps
423 at the expense of duplication of expressions. */
425 if (CONSTANT_CLASS_P (value
)
426 || gimple_code (def_stmt
) == GIMPLE_PHI
428 && (!gimple_assign_single_p (def_stmt
)
429 || is_gimple_min_invariant (value
)))
430 || is_gimple_reg (value
))
431 value
= unshare_expr (value
);
435 tree vexpr
= make_node (DEBUG_EXPR_DECL
);
437 def_temp
= gimple_build_debug_bind (vexpr
,
438 unshare_expr (value
),
441 DECL_ARTIFICIAL (vexpr
) = 1;
442 TREE_TYPE (vexpr
) = TREE_TYPE (value
);
444 DECL_MODE (vexpr
) = DECL_MODE (value
);
446 DECL_MODE (vexpr
) = TYPE_MODE (TREE_TYPE (value
));
449 gsi_insert_before (gsi
, def_temp
, GSI_SAME_STMT
);
452 gimple_stmt_iterator ngsi
= gsi_for_stmt (def_stmt
);
453 gsi_insert_before (&ngsi
, def_temp
, GSI_SAME_STMT
);
460 FOR_EACH_IMM_USE_STMT (stmt
, imm_iter
, var
)
462 if (!gimple_debug_bind_p (stmt
))
467 FOR_EACH_IMM_USE_ON_STMT (use_p
, imm_iter
)
468 /* unshare_expr is not needed here. vexpr is either a
469 SINGLE_RHS, that can be safely shared, some other RHS
470 that was unshared when we found it had a single debug
471 use, or a DEBUG_EXPR_DECL, that can be safely
473 SET_USE (use_p
, value
);
474 /* If we didn't replace uses with a debug decl fold the
475 resulting expression. Otherwise we end up with invalid IL. */
476 if (TREE_CODE (value
) != DEBUG_EXPR_DECL
)
478 gimple_stmt_iterator gsi
= gsi_for_stmt (stmt
);
479 fold_stmt_inplace (&gsi
);
483 gimple_debug_bind_reset_value (stmt
);
490 /* Insert a DEBUG BIND stmt before STMT for each DEF referenced by
491 other DEBUG stmts, and replace uses of the DEF with the
492 newly-created debug temp. */
495 insert_debug_temps_for_defs (gimple_stmt_iterator
*gsi
)
501 if (!MAY_HAVE_DEBUG_STMTS
)
504 stmt
= gsi_stmt (*gsi
);
506 FOR_EACH_PHI_OR_STMT_DEF (def_p
, stmt
, op_iter
, SSA_OP_DEF
)
508 tree var
= DEF_FROM_PTR (def_p
);
510 if (TREE_CODE (var
) != SSA_NAME
)
513 insert_debug_temp_for_var_def (gsi
, var
);
517 /* Reset all debug stmts that use SSA_NAME(s) defined in STMT. */
520 reset_debug_uses (gimple stmt
)
524 imm_use_iterator imm_iter
;
527 if (!MAY_HAVE_DEBUG_STMTS
)
530 FOR_EACH_PHI_OR_STMT_DEF (def_p
, stmt
, op_iter
, SSA_OP_DEF
)
532 tree var
= DEF_FROM_PTR (def_p
);
534 if (TREE_CODE (var
) != SSA_NAME
)
537 FOR_EACH_IMM_USE_STMT (use_stmt
, imm_iter
, var
)
539 if (!gimple_debug_bind_p (use_stmt
))
542 gimple_debug_bind_reset_value (use_stmt
);
543 update_stmt (use_stmt
);
548 /* Delete SSA DEFs for SSA versions in the TOREMOVE bitmap, removing
549 dominated stmts before their dominators, so that release_ssa_defs
550 stands a chance of propagating DEFs into debug bind stmts. */
553 release_defs_bitset (bitmap toremove
)
558 /* Performing a topological sort is probably overkill, this will
559 most likely run in slightly superlinear time, rather than the
560 pathological quadratic worst case. */
561 while (!bitmap_empty_p (toremove
))
562 EXECUTE_IF_SET_IN_BITMAP (toremove
, 0, j
, bi
)
564 bool remove_now
= true;
565 tree var
= ssa_name (j
);
567 imm_use_iterator uit
;
569 FOR_EACH_IMM_USE_STMT (stmt
, uit
, var
)
574 /* We can't propagate PHI nodes into debug stmts. */
575 if (gimple_code (stmt
) == GIMPLE_PHI
576 || is_gimple_debug (stmt
))
579 /* If we find another definition to remove that uses
580 the one we're looking at, defer the removal of this
581 one, so that it can be propagated into debug stmts
582 after the other is. */
583 FOR_EACH_SSA_DEF_OPERAND (def_p
, stmt
, dit
, SSA_OP_DEF
)
585 tree odef
= DEF_FROM_PTR (def_p
);
587 if (bitmap_bit_p (toremove
, SSA_NAME_VERSION (odef
)))
595 BREAK_FROM_IMM_USE_STMT (uit
);
600 gimple def
= SSA_NAME_DEF_STMT (var
);
601 gimple_stmt_iterator gsi
= gsi_for_stmt (def
);
603 if (gimple_code (def
) == GIMPLE_PHI
)
604 remove_phi_node (&gsi
, true);
607 gsi_remove (&gsi
, true);
611 bitmap_clear_bit (toremove
, j
);
616 /* Return true if SSA_NAME is malformed and mark it visited.
618 IS_VIRTUAL is true if this SSA_NAME was found inside a virtual
622 verify_ssa_name (tree ssa_name
, bool is_virtual
)
624 if (TREE_CODE (ssa_name
) != SSA_NAME
)
626 error ("expected an SSA_NAME object");
630 if (SSA_NAME_VAR (ssa_name
) != NULL_TREE
631 && TREE_TYPE (ssa_name
) != TREE_TYPE (ssa_name
))
633 error ("type mismatch between an SSA_NAME and its symbol");
637 if (SSA_NAME_IN_FREE_LIST (ssa_name
))
639 error ("found an SSA_NAME that had been released into the free pool");
643 if (is_virtual
&& !virtual_operand_p (ssa_name
))
645 error ("found a virtual definition for a GIMPLE register");
649 if (is_virtual
&& SSA_NAME_VAR (ssa_name
) != gimple_vop (cfun
))
651 error ("virtual SSA name for non-VOP decl");
655 if (!is_virtual
&& virtual_operand_p (ssa_name
))
657 error ("found a real definition for a non-register");
661 if (SSA_NAME_IS_DEFAULT_DEF (ssa_name
)
662 && !gimple_nop_p (SSA_NAME_DEF_STMT (ssa_name
)))
664 error ("found a default name with a non-empty defining statement");
672 /* Return true if the definition of SSA_NAME at block BB is malformed.
674 STMT is the statement where SSA_NAME is created.
676 DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME
677 version numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set,
678 it means that the block in that array slot contains the
679 definition of SSA_NAME.
681 IS_VIRTUAL is true if SSA_NAME is created by a VDEF. */
684 verify_def (basic_block bb
, basic_block
*definition_block
, tree ssa_name
,
685 gimple stmt
, bool is_virtual
)
687 if (verify_ssa_name (ssa_name
, is_virtual
))
690 if (SSA_NAME_VAR (ssa_name
)
691 && TREE_CODE (SSA_NAME_VAR (ssa_name
)) == RESULT_DECL
692 && DECL_BY_REFERENCE (SSA_NAME_VAR (ssa_name
)))
694 error ("RESULT_DECL should be read only when DECL_BY_REFERENCE is set");
698 if (definition_block
[SSA_NAME_VERSION (ssa_name
)])
700 error ("SSA_NAME created in two different blocks %i and %i",
701 definition_block
[SSA_NAME_VERSION (ssa_name
)]->index
, bb
->index
);
705 definition_block
[SSA_NAME_VERSION (ssa_name
)] = bb
;
707 if (SSA_NAME_DEF_STMT (ssa_name
) != stmt
)
709 error ("SSA_NAME_DEF_STMT is wrong");
710 fprintf (stderr
, "Expected definition statement:\n");
711 print_gimple_stmt (stderr
, SSA_NAME_DEF_STMT (ssa_name
), 4, TDF_VOPS
);
712 fprintf (stderr
, "\nActual definition statement:\n");
713 print_gimple_stmt (stderr
, stmt
, 4, TDF_VOPS
);
720 fprintf (stderr
, "while verifying SSA_NAME ");
721 print_generic_expr (stderr
, ssa_name
, 0);
722 fprintf (stderr
, " in statement\n");
723 print_gimple_stmt (stderr
, stmt
, 4, TDF_VOPS
);
729 /* Return true if the use of SSA_NAME at statement STMT in block BB is
732 DEF_BB is the block where SSA_NAME was found to be created.
734 IDOM contains immediate dominator information for the flowgraph.
736 CHECK_ABNORMAL is true if the caller wants to check whether this use
737 is flowing through an abnormal edge (only used when checking PHI
740 If NAMES_DEFINED_IN_BB is not NULL, it contains a bitmap of ssa names
741 that are defined before STMT in basic block BB. */
744 verify_use (basic_block bb
, basic_block def_bb
, use_operand_p use_p
,
745 gimple stmt
, bool check_abnormal
, bitmap names_defined_in_bb
)
748 tree ssa_name
= USE_FROM_PTR (use_p
);
750 if (!TREE_VISITED (ssa_name
))
751 if (verify_imm_links (stderr
, ssa_name
))
754 TREE_VISITED (ssa_name
) = 1;
756 if (gimple_nop_p (SSA_NAME_DEF_STMT (ssa_name
))
757 && SSA_NAME_IS_DEFAULT_DEF (ssa_name
))
758 ; /* Default definitions have empty statements. Nothing to do. */
761 error ("missing definition");
764 else if (bb
!= def_bb
765 && !dominated_by_p (CDI_DOMINATORS
, bb
, def_bb
))
767 error ("definition in block %i does not dominate use in block %i",
768 def_bb
->index
, bb
->index
);
771 else if (bb
== def_bb
772 && names_defined_in_bb
!= NULL
773 && !bitmap_bit_p (names_defined_in_bb
, SSA_NAME_VERSION (ssa_name
)))
775 error ("definition in block %i follows the use", def_bb
->index
);
780 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ssa_name
))
782 error ("SSA_NAME_OCCURS_IN_ABNORMAL_PHI should be set");
786 /* Make sure the use is in an appropriate list by checking the previous
787 element to make sure it's the same. */
788 if (use_p
->prev
== NULL
)
790 error ("no immediate_use list");
796 if (use_p
->prev
->use
== NULL
)
797 listvar
= use_p
->prev
->loc
.ssa_name
;
799 listvar
= USE_FROM_PTR (use_p
->prev
);
800 if (listvar
!= ssa_name
)
802 error ("wrong immediate use list");
809 fprintf (stderr
, "for SSA_NAME: ");
810 print_generic_expr (stderr
, ssa_name
, TDF_VOPS
);
811 fprintf (stderr
, " in statement:\n");
812 print_gimple_stmt (stderr
, stmt
, 0, TDF_VOPS
);
819 /* Return true if any of the arguments for PHI node PHI at block BB is
822 DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME
823 version numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set,
824 it means that the block in that array slot contains the
825 definition of SSA_NAME. */
828 verify_phi_args (gimple phi
, basic_block bb
, basic_block
*definition_block
)
832 size_t i
, phi_num_args
= gimple_phi_num_args (phi
);
834 if (EDGE_COUNT (bb
->preds
) != phi_num_args
)
836 error ("incoming edge count does not match number of PHI arguments");
841 for (i
= 0; i
< phi_num_args
; i
++)
843 use_operand_p op_p
= gimple_phi_arg_imm_use_ptr (phi
, i
);
844 tree op
= USE_FROM_PTR (op_p
);
846 e
= EDGE_PRED (bb
, i
);
850 error ("PHI argument is missing for edge %d->%d",
857 if (TREE_CODE (op
) != SSA_NAME
&& !is_gimple_min_invariant (op
))
859 error ("PHI argument is not SSA_NAME, or invariant");
863 if (TREE_CODE (op
) == SSA_NAME
)
865 err
= verify_ssa_name (op
, virtual_operand_p (gimple_phi_result (phi
)));
866 err
|= verify_use (e
->src
, definition_block
[SSA_NAME_VERSION (op
)],
867 op_p
, phi
, e
->flags
& EDGE_ABNORMAL
, NULL
);
870 if (TREE_CODE (op
) == ADDR_EXPR
)
872 tree base
= TREE_OPERAND (op
, 0);
873 while (handled_component_p (base
))
874 base
= TREE_OPERAND (base
, 0);
875 if ((TREE_CODE (base
) == VAR_DECL
876 || TREE_CODE (base
) == PARM_DECL
877 || TREE_CODE (base
) == RESULT_DECL
)
878 && !TREE_ADDRESSABLE (base
))
880 error ("address taken, but ADDRESSABLE bit not set");
887 error ("wrong edge %d->%d for PHI argument",
888 e
->src
->index
, e
->dest
->index
);
894 fprintf (stderr
, "PHI argument\n");
895 print_generic_stmt (stderr
, op
, TDF_VOPS
);
903 fprintf (stderr
, "for PHI node\n");
904 print_gimple_stmt (stderr
, phi
, 0, TDF_VOPS
|TDF_MEMSYMS
);
912 /* Verify common invariants in the SSA web.
913 TODO: verify the variable annotations. */
916 verify_ssa (bool check_modified_stmt
)
920 basic_block
*definition_block
= XCNEWVEC (basic_block
, num_ssa_names
);
923 enum dom_state orig_dom_state
= dom_info_state (CDI_DOMINATORS
);
924 bitmap names_defined_in_bb
= BITMAP_ALLOC (NULL
);
926 gcc_assert (!need_ssa_update_p (cfun
));
928 timevar_push (TV_TREE_SSA_VERIFY
);
930 /* Keep track of SSA names present in the IL. */
931 for (i
= 1; i
< num_ssa_names
; i
++)
933 tree name
= ssa_name (i
);
937 TREE_VISITED (name
) = 0;
939 verify_ssa_name (name
, virtual_operand_p (name
));
941 stmt
= SSA_NAME_DEF_STMT (name
);
942 if (!gimple_nop_p (stmt
))
944 basic_block bb
= gimple_bb (stmt
);
945 verify_def (bb
, definition_block
,
946 name
, stmt
, virtual_operand_p (name
));
952 calculate_dominance_info (CDI_DOMINATORS
);
954 /* Now verify all the uses and make sure they agree with the definitions
955 found in the previous pass. */
961 gimple_stmt_iterator gsi
;
963 /* Make sure that all edges have a clear 'aux' field. */
964 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
968 error ("AUX pointer initialized for edge %d->%d", e
->src
->index
,
974 /* Verify the arguments for every PHI node in the block. */
975 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
977 phi
= gsi_stmt (gsi
);
978 if (verify_phi_args (phi
, bb
, definition_block
))
981 bitmap_set_bit (names_defined_in_bb
,
982 SSA_NAME_VERSION (gimple_phi_result (phi
)));
985 /* Now verify all the uses and vuses in every statement of the block. */
986 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
988 gimple stmt
= gsi_stmt (gsi
);
991 if (check_modified_stmt
&& gimple_modified_p (stmt
))
993 error ("stmt (%p) marked modified after optimization pass: ",
995 print_gimple_stmt (stderr
, stmt
, 0, TDF_VOPS
);
999 if (verify_ssa_operands (stmt
))
1001 print_gimple_stmt (stderr
, stmt
, 0, TDF_VOPS
);
1005 if (gimple_debug_bind_p (stmt
)
1006 && !gimple_debug_bind_has_value_p (stmt
))
1009 FOR_EACH_SSA_USE_OPERAND (use_p
, stmt
, iter
, SSA_OP_USE
|SSA_OP_VUSE
)
1011 op
= USE_FROM_PTR (use_p
);
1012 if (verify_use (bb
, definition_block
[SSA_NAME_VERSION (op
)],
1013 use_p
, stmt
, false, names_defined_in_bb
))
1017 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_ALL_DEFS
)
1019 if (SSA_NAME_DEF_STMT (op
) != stmt
)
1021 error ("SSA_NAME_DEF_STMT is wrong");
1022 fprintf (stderr
, "Expected definition statement:\n");
1023 print_gimple_stmt (stderr
, stmt
, 4, TDF_VOPS
);
1024 fprintf (stderr
, "\nActual definition statement:\n");
1025 print_gimple_stmt (stderr
, SSA_NAME_DEF_STMT (op
),
1029 bitmap_set_bit (names_defined_in_bb
, SSA_NAME_VERSION (op
));
1033 bitmap_clear (names_defined_in_bb
);
1036 free (definition_block
);
1038 /* Restore the dominance information to its prior known state, so
1039 that we do not perturb the compiler's subsequent behavior. */
1040 if (orig_dom_state
== DOM_NONE
)
1041 free_dominance_info (CDI_DOMINATORS
);
1043 set_dom_info_availability (CDI_DOMINATORS
, orig_dom_state
);
1045 BITMAP_FREE (names_defined_in_bb
);
1046 timevar_pop (TV_TREE_SSA_VERIFY
);
1050 internal_error ("verify_ssa failed");
1053 /* Return true if the uid in both int tree maps are equal. */
1056 int_tree_map_eq (const void *va
, const void *vb
)
1058 const struct int_tree_map
*a
= (const struct int_tree_map
*) va
;
1059 const struct int_tree_map
*b
= (const struct int_tree_map
*) vb
;
1060 return (a
->uid
== b
->uid
);
1063 /* Hash a UID in a int_tree_map. */
1066 int_tree_map_hash (const void *item
)
1068 return ((const struct int_tree_map
*)item
)->uid
;
1071 /* Return true if the DECL_UID in both trees are equal. */
1074 uid_decl_map_eq (const void *va
, const void *vb
)
1076 const_tree a
= (const_tree
) va
;
1077 const_tree b
= (const_tree
) vb
;
1078 return (a
->decl_minimal
.uid
== b
->decl_minimal
.uid
);
1081 /* Hash a tree in a uid_decl_map. */
1084 uid_decl_map_hash (const void *item
)
1086 return ((const_tree
)item
)->decl_minimal
.uid
;
1089 /* Return true if the DECL_UID in both trees are equal. */
1092 uid_ssaname_map_eq (const void *va
, const void *vb
)
1094 const_tree a
= (const_tree
) va
;
1095 const_tree b
= (const_tree
) vb
;
1096 return (a
->ssa_name
.var
->decl_minimal
.uid
== b
->ssa_name
.var
->decl_minimal
.uid
);
1099 /* Hash a tree in a uid_decl_map. */
1102 uid_ssaname_map_hash (const void *item
)
1104 return ((const_tree
)item
)->ssa_name
.var
->decl_minimal
.uid
;
1108 /* Initialize global DFA and SSA structures. */
1111 init_tree_ssa (struct function
*fn
)
1113 fn
->gimple_df
= ggc_alloc_cleared_gimple_df ();
1114 fn
->gimple_df
->default_defs
= htab_create_ggc (20, uid_ssaname_map_hash
,
1115 uid_ssaname_map_eq
, NULL
);
1116 pt_solution_reset (&fn
->gimple_df
->escaped
);
1117 init_ssanames (fn
, 0);
1120 /* Do the actions required to initialize internal data structures used
1121 in tree-ssa optimization passes. */
1124 execute_init_datastructures (void)
1126 /* Allocate hash tables, arrays and other structures. */
1127 init_tree_ssa (cfun
);
1131 struct gimple_opt_pass pass_init_datastructures
=
1135 "*init_datastructures", /* name */
1136 OPTGROUP_NONE
, /* optinfo_flags */
1138 execute_init_datastructures
, /* execute */
1141 0, /* static_pass_number */
1142 TV_NONE
, /* tv_id */
1143 PROP_cfg
, /* properties_required */
1144 0, /* properties_provided */
1145 0, /* properties_destroyed */
1146 0, /* todo_flags_start */
1147 0 /* todo_flags_finish */
1151 /* Deallocate memory associated with SSA data structures for FNDECL. */
1154 delete_tree_ssa (void)
1158 /* We no longer maintain the SSA operand cache at this point. */
1159 if (ssa_operands_active (cfun
))
1160 fini_ssa_operands ();
1162 htab_delete (cfun
->gimple_df
->default_defs
);
1163 cfun
->gimple_df
->default_defs
= NULL
;
1164 pt_solution_reset (&cfun
->gimple_df
->escaped
);
1165 if (cfun
->gimple_df
->decls_to_pointers
!= NULL
)
1166 pointer_map_destroy (cfun
->gimple_df
->decls_to_pointers
);
1167 cfun
->gimple_df
->decls_to_pointers
= NULL
;
1168 cfun
->gimple_df
->modified_noreturn_calls
= NULL
;
1169 cfun
->gimple_df
= NULL
;
1171 /* We no longer need the edge variable maps. */
1172 redirect_edge_var_map_destroy ();
1175 /* Return true if the conversion from INNER_TYPE to OUTER_TYPE is a
1176 useless type conversion, otherwise return false.
1178 This function implicitly defines the middle-end type system. With
1179 the notion of 'a < b' meaning that useless_type_conversion_p (a, b)
1180 holds and 'a > b' meaning that useless_type_conversion_p (b, a) holds,
1181 the following invariants shall be fulfilled:
1183 1) useless_type_conversion_p is transitive.
1184 If a < b and b < c then a < c.
1186 2) useless_type_conversion_p is not symmetric.
1187 From a < b does not follow a > b.
1189 3) Types define the available set of operations applicable to values.
1190 A type conversion is useless if the operations for the target type
1191 is a subset of the operations for the source type. For example
1192 casts to void* are useless, casts from void* are not (void* can't
1193 be dereferenced or offsetted, but copied, hence its set of operations
1194 is a strict subset of that of all other data pointer types). Casts
1195 to const T* are useless (can't be written to), casts from const T*
1199 useless_type_conversion_p (tree outer_type
, tree inner_type
)
1201 /* Do the following before stripping toplevel qualifiers. */
1202 if (POINTER_TYPE_P (inner_type
)
1203 && POINTER_TYPE_P (outer_type
))
1205 /* Do not lose casts between pointers to different address spaces. */
1206 if (TYPE_ADDR_SPACE (TREE_TYPE (outer_type
))
1207 != TYPE_ADDR_SPACE (TREE_TYPE (inner_type
)))
1211 /* From now on qualifiers on value types do not matter. */
1212 inner_type
= TYPE_MAIN_VARIANT (inner_type
);
1213 outer_type
= TYPE_MAIN_VARIANT (outer_type
);
1215 if (inner_type
== outer_type
)
1218 /* If we know the canonical types, compare them. */
1219 if (TYPE_CANONICAL (inner_type
)
1220 && TYPE_CANONICAL (inner_type
) == TYPE_CANONICAL (outer_type
))
1223 /* Changes in machine mode are never useless conversions unless we
1224 deal with aggregate types in which case we defer to later checks. */
1225 if (TYPE_MODE (inner_type
) != TYPE_MODE (outer_type
)
1226 && !AGGREGATE_TYPE_P (inner_type
))
1229 /* If both the inner and outer types are integral types, then the
1230 conversion is not necessary if they have the same mode and
1231 signedness and precision, and both or neither are boolean. */
1232 if (INTEGRAL_TYPE_P (inner_type
)
1233 && INTEGRAL_TYPE_P (outer_type
))
1235 /* Preserve changes in signedness or precision. */
1236 if (TYPE_UNSIGNED (inner_type
) != TYPE_UNSIGNED (outer_type
)
1237 || TYPE_PRECISION (inner_type
) != TYPE_PRECISION (outer_type
))
1240 /* Preserve conversions to/from BOOLEAN_TYPE if types are not
1241 of precision one. */
1242 if (((TREE_CODE (inner_type
) == BOOLEAN_TYPE
)
1243 != (TREE_CODE (outer_type
) == BOOLEAN_TYPE
))
1244 && TYPE_PRECISION (outer_type
) != 1)
1247 /* We don't need to preserve changes in the types minimum or
1248 maximum value in general as these do not generate code
1249 unless the types precisions are different. */
1253 /* Scalar floating point types with the same mode are compatible. */
1254 else if (SCALAR_FLOAT_TYPE_P (inner_type
)
1255 && SCALAR_FLOAT_TYPE_P (outer_type
))
1258 /* Fixed point types with the same mode are compatible. */
1259 else if (FIXED_POINT_TYPE_P (inner_type
)
1260 && FIXED_POINT_TYPE_P (outer_type
))
1263 /* We need to take special care recursing to pointed-to types. */
1264 else if (POINTER_TYPE_P (inner_type
)
1265 && POINTER_TYPE_P (outer_type
))
1267 /* Do not lose casts to function pointer types. */
1268 if ((TREE_CODE (TREE_TYPE (outer_type
)) == FUNCTION_TYPE
1269 || TREE_CODE (TREE_TYPE (outer_type
)) == METHOD_TYPE
)
1270 && !(TREE_CODE (TREE_TYPE (inner_type
)) == FUNCTION_TYPE
1271 || TREE_CODE (TREE_TYPE (inner_type
)) == METHOD_TYPE
))
1274 /* We do not care for const qualification of the pointed-to types
1275 as const qualification has no semantic value to the middle-end. */
1277 /* Otherwise pointers/references are equivalent. */
1281 /* Recurse for complex types. */
1282 else if (TREE_CODE (inner_type
) == COMPLEX_TYPE
1283 && TREE_CODE (outer_type
) == COMPLEX_TYPE
)
1284 return useless_type_conversion_p (TREE_TYPE (outer_type
),
1285 TREE_TYPE (inner_type
));
1287 /* Recurse for vector types with the same number of subparts. */
1288 else if (TREE_CODE (inner_type
) == VECTOR_TYPE
1289 && TREE_CODE (outer_type
) == VECTOR_TYPE
1290 && TYPE_PRECISION (inner_type
) == TYPE_PRECISION (outer_type
))
1291 return useless_type_conversion_p (TREE_TYPE (outer_type
),
1292 TREE_TYPE (inner_type
));
1294 else if (TREE_CODE (inner_type
) == ARRAY_TYPE
1295 && TREE_CODE (outer_type
) == ARRAY_TYPE
)
1297 /* Preserve string attributes. */
1298 if (TYPE_STRING_FLAG (inner_type
) != TYPE_STRING_FLAG (outer_type
))
1301 /* Conversions from array types with unknown extent to
1302 array types with known extent are not useless. */
1303 if (!TYPE_DOMAIN (inner_type
)
1304 && TYPE_DOMAIN (outer_type
))
1307 /* Nor are conversions from array types with non-constant size to
1308 array types with constant size or to different size. */
1309 if (TYPE_SIZE (outer_type
)
1310 && TREE_CODE (TYPE_SIZE (outer_type
)) == INTEGER_CST
1311 && (!TYPE_SIZE (inner_type
)
1312 || TREE_CODE (TYPE_SIZE (inner_type
)) != INTEGER_CST
1313 || !tree_int_cst_equal (TYPE_SIZE (outer_type
),
1314 TYPE_SIZE (inner_type
))))
1317 /* Check conversions between arrays with partially known extents.
1318 If the array min/max values are constant they have to match.
1319 Otherwise allow conversions to unknown and variable extents.
1320 In particular this declares conversions that may change the
1321 mode to BLKmode as useless. */
1322 if (TYPE_DOMAIN (inner_type
)
1323 && TYPE_DOMAIN (outer_type
)
1324 && TYPE_DOMAIN (inner_type
) != TYPE_DOMAIN (outer_type
))
1326 tree inner_min
= TYPE_MIN_VALUE (TYPE_DOMAIN (inner_type
));
1327 tree outer_min
= TYPE_MIN_VALUE (TYPE_DOMAIN (outer_type
));
1328 tree inner_max
= TYPE_MAX_VALUE (TYPE_DOMAIN (inner_type
));
1329 tree outer_max
= TYPE_MAX_VALUE (TYPE_DOMAIN (outer_type
));
1331 /* After gimplification a variable min/max value carries no
1332 additional information compared to a NULL value. All that
1333 matters has been lowered to be part of the IL. */
1334 if (inner_min
&& TREE_CODE (inner_min
) != INTEGER_CST
)
1335 inner_min
= NULL_TREE
;
1336 if (outer_min
&& TREE_CODE (outer_min
) != INTEGER_CST
)
1337 outer_min
= NULL_TREE
;
1338 if (inner_max
&& TREE_CODE (inner_max
) != INTEGER_CST
)
1339 inner_max
= NULL_TREE
;
1340 if (outer_max
&& TREE_CODE (outer_max
) != INTEGER_CST
)
1341 outer_max
= NULL_TREE
;
1343 /* Conversions NULL / variable <- cst are useless, but not
1344 the other way around. */
1347 || !tree_int_cst_equal (inner_min
, outer_min
)))
1351 || !tree_int_cst_equal (inner_max
, outer_max
)))
1355 /* Recurse on the element check. */
1356 return useless_type_conversion_p (TREE_TYPE (outer_type
),
1357 TREE_TYPE (inner_type
));
1360 else if ((TREE_CODE (inner_type
) == FUNCTION_TYPE
1361 || TREE_CODE (inner_type
) == METHOD_TYPE
)
1362 && TREE_CODE (inner_type
) == TREE_CODE (outer_type
))
1364 tree outer_parm
, inner_parm
;
1366 /* If the return types are not compatible bail out. */
1367 if (!useless_type_conversion_p (TREE_TYPE (outer_type
),
1368 TREE_TYPE (inner_type
)))
1371 /* Method types should belong to a compatible base class. */
1372 if (TREE_CODE (inner_type
) == METHOD_TYPE
1373 && !useless_type_conversion_p (TYPE_METHOD_BASETYPE (outer_type
),
1374 TYPE_METHOD_BASETYPE (inner_type
)))
1377 /* A conversion to an unprototyped argument list is ok. */
1378 if (!prototype_p (outer_type
))
1381 /* If the unqualified argument types are compatible the conversion
1383 if (TYPE_ARG_TYPES (outer_type
) == TYPE_ARG_TYPES (inner_type
))
1386 for (outer_parm
= TYPE_ARG_TYPES (outer_type
),
1387 inner_parm
= TYPE_ARG_TYPES (inner_type
);
1388 outer_parm
&& inner_parm
;
1389 outer_parm
= TREE_CHAIN (outer_parm
),
1390 inner_parm
= TREE_CHAIN (inner_parm
))
1391 if (!useless_type_conversion_p
1392 (TYPE_MAIN_VARIANT (TREE_VALUE (outer_parm
)),
1393 TYPE_MAIN_VARIANT (TREE_VALUE (inner_parm
))))
1396 /* If there is a mismatch in the number of arguments the functions
1397 are not compatible. */
1398 if (outer_parm
|| inner_parm
)
1401 /* Defer to the target if necessary. */
1402 if (TYPE_ATTRIBUTES (inner_type
) || TYPE_ATTRIBUTES (outer_type
))
1403 return comp_type_attributes (outer_type
, inner_type
) != 0;
1408 /* For aggregates we rely on TYPE_CANONICAL exclusively and require
1409 explicit conversions for types involving to be structurally
1411 else if (AGGREGATE_TYPE_P (inner_type
)
1412 && TREE_CODE (inner_type
) == TREE_CODE (outer_type
))
1418 /* Return true if a conversion from either type of TYPE1 and TYPE2
1419 to the other is not required. Otherwise return false. */
1422 types_compatible_p (tree type1
, tree type2
)
1424 return (type1
== type2
1425 || (useless_type_conversion_p (type1
, type2
)
1426 && useless_type_conversion_p (type2
, type1
)));
1429 /* Return true if EXPR is a useless type conversion, otherwise return
1433 tree_ssa_useless_type_conversion (tree expr
)
1435 /* If we have an assignment that merely uses a NOP_EXPR to change
1436 the top of the RHS to the type of the LHS and the type conversion
1437 is "safe", then strip away the type conversion so that we can
1438 enter LHS = RHS into the const_and_copies table. */
1439 if (CONVERT_EXPR_P (expr
)
1440 || TREE_CODE (expr
) == VIEW_CONVERT_EXPR
1441 || TREE_CODE (expr
) == NON_LVALUE_EXPR
)
1442 return useless_type_conversion_p
1444 TREE_TYPE (TREE_OPERAND (expr
, 0)));
1449 /* Strip conversions from EXP according to
1450 tree_ssa_useless_type_conversion and return the resulting
1454 tree_ssa_strip_useless_type_conversions (tree exp
)
1456 while (tree_ssa_useless_type_conversion (exp
))
1457 exp
= TREE_OPERAND (exp
, 0);
1462 /* Internal helper for walk_use_def_chains. VAR, FN and DATA are as
1463 described in walk_use_def_chains.
1465 VISITED is a pointer set used to mark visited SSA_NAMEs to avoid
1466 infinite loops. We used to have a bitmap for this to just mark
1467 SSA versions we had visited. But non-sparse bitmaps are way too
1468 expensive, while sparse bitmaps may cause quadratic behavior.
1470 IS_DFS is true if the caller wants to perform a depth-first search
1471 when visiting PHI nodes. A DFS will visit each PHI argument and
1472 call FN after each one. Otherwise, all the arguments are
1473 visited first and then FN is called with each of the visited
1474 arguments in a separate pass. */
1477 walk_use_def_chains_1 (tree var
, walk_use_def_chains_fn fn
, void *data
,
1478 struct pointer_set_t
*visited
, bool is_dfs
)
1482 if (pointer_set_insert (visited
, var
))
1485 def_stmt
= SSA_NAME_DEF_STMT (var
);
1487 if (gimple_code (def_stmt
) != GIMPLE_PHI
)
1489 /* If we reached the end of the use-def chain, call FN. */
1490 return fn (var
, def_stmt
, data
);
1496 /* When doing a breadth-first search, call FN before following the
1497 use-def links for each argument. */
1499 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); i
++)
1500 if (fn (gimple_phi_arg_def (def_stmt
, i
), def_stmt
, data
))
1503 /* Follow use-def links out of each PHI argument. */
1504 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); i
++)
1506 tree arg
= gimple_phi_arg_def (def_stmt
, i
);
1508 /* ARG may be NULL for newly introduced PHI nodes. */
1510 && TREE_CODE (arg
) == SSA_NAME
1511 && walk_use_def_chains_1 (arg
, fn
, data
, visited
, is_dfs
))
1515 /* When doing a depth-first search, call FN after following the
1516 use-def links for each argument. */
1518 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); i
++)
1519 if (fn (gimple_phi_arg_def (def_stmt
, i
), def_stmt
, data
))
1528 /* Walk use-def chains starting at the SSA variable VAR. Call
1529 function FN at each reaching definition found. FN takes three
1530 arguments: VAR, its defining statement (DEF_STMT) and a generic
1531 pointer to whatever state information that FN may want to maintain
1532 (DATA). FN is able to stop the walk by returning true, otherwise
1533 in order to continue the walk, FN should return false.
1535 Note, that if DEF_STMT is a PHI node, the semantics are slightly
1536 different. The first argument to FN is no longer the original
1537 variable VAR, but the PHI argument currently being examined. If FN
1538 wants to get at VAR, it should call PHI_RESULT (PHI).
1540 If IS_DFS is true, this function will:
1542 1- walk the use-def chains for all the PHI arguments, and,
1543 2- call (*FN) (ARG, PHI, DATA) on all the PHI arguments.
1545 If IS_DFS is false, the two steps above are done in reverse order
1546 (i.e., a breadth-first search). */
1549 walk_use_def_chains (tree var
, walk_use_def_chains_fn fn
, void *data
,
1554 gcc_assert (TREE_CODE (var
) == SSA_NAME
);
1556 def_stmt
= SSA_NAME_DEF_STMT (var
);
1558 /* We only need to recurse if the reaching definition comes from a PHI
1560 if (gimple_code (def_stmt
) != GIMPLE_PHI
)
1561 (*fn
) (var
, def_stmt
, data
);
1564 struct pointer_set_t
*visited
= pointer_set_create ();
1565 walk_use_def_chains_1 (var
, fn
, data
, visited
, is_dfs
);
1566 pointer_set_destroy (visited
);
1571 /* Emit warnings for uninitialized variables. This is done in two passes.
1573 The first pass notices real uses of SSA names with undefined values.
1574 Such uses are unconditionally uninitialized, and we can be certain that
1575 such a use is a mistake. This pass is run before most optimizations,
1576 so that we catch as many as we can.
1578 The second pass follows PHI nodes to find uses that are potentially
1579 uninitialized. In this case we can't necessarily prove that the use
1580 is really uninitialized. This pass is run after most optimizations,
1581 so that we thread as many jumps and possible, and delete as much dead
1582 code as possible, in order to reduce false positives. We also look
1583 again for plain uninitialized variables, since optimization may have
1584 changed conditionally uninitialized to unconditionally uninitialized. */
1586 /* Emit a warning for EXPR based on variable VAR at the point in the
1587 program T, an SSA_NAME, is used being uninitialized. The exact
1588 warning text is in MSGID and LOCUS may contain a location or be null.
1589 WC is the warning code. */
1592 warn_uninit (enum opt_code wc
, tree t
,
1593 tree expr
, tree var
, const char *gmsgid
, void *data
)
1595 gimple context
= (gimple
) data
;
1596 location_t location
, cfun_loc
;
1597 expanded_location xloc
, floc
;
1599 if (!ssa_undefined_value_p (t
))
1602 /* TREE_NO_WARNING either means we already warned, or the front end
1603 wishes to suppress the warning. */
1605 && (gimple_no_warning_p (context
)
1606 || (gimple_assign_single_p (context
)
1607 && TREE_NO_WARNING (gimple_assign_rhs1 (context
)))))
1608 || TREE_NO_WARNING (expr
))
1611 location
= (context
!= NULL
&& gimple_has_location (context
))
1612 ? gimple_location (context
)
1613 : DECL_SOURCE_LOCATION (var
);
1614 location
= linemap_resolve_location (line_table
, location
,
1615 LRK_SPELLING_LOCATION
,
1617 cfun_loc
= DECL_SOURCE_LOCATION (cfun
->decl
);
1618 xloc
= expand_location (location
);
1619 floc
= expand_location (cfun_loc
);
1620 if (warning_at (location
, wc
, gmsgid
, expr
))
1622 TREE_NO_WARNING (expr
) = 1;
1624 if (location
== DECL_SOURCE_LOCATION (var
))
1626 if (xloc
.file
!= floc
.file
1627 || linemap_location_before_p (line_table
,
1629 || linemap_location_before_p (line_table
,
1630 cfun
->function_end_locus
,
1632 inform (DECL_SOURCE_LOCATION (var
), "%qD was declared here", var
);
1637 warn_uninitialized_vars (bool warn_possibly_uninitialized
)
1639 gimple_stmt_iterator gsi
;
1644 bool always_executed
= dominated_by_p (CDI_POST_DOMINATORS
,
1645 single_succ (ENTRY_BLOCK_PTR
), bb
);
1646 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1648 gimple stmt
= gsi_stmt (gsi
);
1649 use_operand_p use_p
;
1650 ssa_op_iter op_iter
;
1653 if (is_gimple_debug (stmt
))
1656 /* We only do data flow with SSA_NAMEs, so that's all we
1658 FOR_EACH_SSA_USE_OPERAND (use_p
, stmt
, op_iter
, SSA_OP_USE
)
1660 use
= USE_FROM_PTR (use_p
);
1661 if (always_executed
)
1662 warn_uninit (OPT_Wuninitialized
, use
,
1663 SSA_NAME_VAR (use
), SSA_NAME_VAR (use
),
1664 "%qD is used uninitialized in this function",
1666 else if (warn_possibly_uninitialized
)
1667 warn_uninit (OPT_Wmaybe_uninitialized
, use
,
1668 SSA_NAME_VAR (use
), SSA_NAME_VAR (use
),
1669 "%qD may be used uninitialized in this function",
1673 /* For memory the only cheap thing we can do is see if we
1674 have a use of the default def of the virtual operand.
1675 ??? Note that at -O0 we do not have virtual operands.
1676 ??? Not so cheap would be to use the alias oracle via
1677 walk_aliased_vdefs, if we don't find any aliasing vdef
1678 warn as is-used-uninitialized, if we don't find an aliasing
1679 vdef that kills our use (stmt_kills_ref_p), warn as
1680 may-be-used-uninitialized. But this walk is quadratic and
1681 so must be limited which means we would miss warning
1683 use
= gimple_vuse (stmt
);
1685 && gimple_assign_single_p (stmt
)
1686 && !gimple_vdef (stmt
)
1687 && SSA_NAME_IS_DEFAULT_DEF (use
))
1689 tree rhs
= gimple_assign_rhs1 (stmt
);
1690 tree base
= get_base_address (rhs
);
1692 /* Do not warn if it can be initialized outside this function. */
1693 if (TREE_CODE (base
) != VAR_DECL
1694 || DECL_HARD_REGISTER (base
)
1695 || is_global_var (base
))
1698 if (always_executed
)
1699 warn_uninit (OPT_Wuninitialized
, use
,
1700 gimple_assign_rhs1 (stmt
), base
,
1701 "%qE is used uninitialized in this function",
1703 else if (warn_possibly_uninitialized
)
1704 warn_uninit (OPT_Wmaybe_uninitialized
, use
,
1705 gimple_assign_rhs1 (stmt
), base
,
1706 "%qE may be used uninitialized in this function",
1716 execute_early_warn_uninitialized (void)
1718 /* Currently, this pass runs always but
1719 execute_late_warn_uninitialized only runs with optimization. With
1720 optimization we want to warn about possible uninitialized as late
1721 as possible, thus don't do it here. However, without
1722 optimization we need to warn here about "may be uninitialized".
1724 calculate_dominance_info (CDI_POST_DOMINATORS
);
1726 warn_uninitialized_vars (/*warn_possibly_uninitialized=*/!optimize
);
1728 /* Post-dominator information can not be reliably updated. Free it
1731 free_dominance_info (CDI_POST_DOMINATORS
);
1736 gate_warn_uninitialized (void)
1738 return warn_uninitialized
!= 0;
1741 struct gimple_opt_pass pass_early_warn_uninitialized
=
1745 "*early_warn_uninitialized", /* name */
1746 OPTGROUP_NONE
, /* optinfo_flags */
1747 gate_warn_uninitialized
, /* gate */
1748 execute_early_warn_uninitialized
, /* execute */
1751 0, /* static_pass_number */
1752 TV_TREE_UNINIT
, /* tv_id */
1753 PROP_ssa
, /* properties_required */
1754 0, /* properties_provided */
1755 0, /* properties_destroyed */
1756 0, /* todo_flags_start */
1757 0 /* todo_flags_finish */
1762 /* If necessary, rewrite the base of the reference tree *TP from
1763 a MEM_REF to a plain or converted symbol. */
1766 maybe_rewrite_mem_ref_base (tree
*tp
, bitmap suitable_for_renaming
)
1770 while (handled_component_p (*tp
))
1771 tp
= &TREE_OPERAND (*tp
, 0);
1772 if (TREE_CODE (*tp
) == MEM_REF
1773 && TREE_CODE (TREE_OPERAND (*tp
, 0)) == ADDR_EXPR
1774 && (sym
= TREE_OPERAND (TREE_OPERAND (*tp
, 0), 0))
1776 && !TREE_ADDRESSABLE (sym
)
1777 && bitmap_bit_p (suitable_for_renaming
, DECL_UID (sym
)))
1779 if (TREE_CODE (TREE_TYPE (sym
)) == VECTOR_TYPE
1780 && useless_type_conversion_p (TREE_TYPE (*tp
),
1781 TREE_TYPE (TREE_TYPE (sym
)))
1782 && multiple_of_p (sizetype
, TREE_OPERAND (*tp
, 1),
1783 TYPE_SIZE_UNIT (TREE_TYPE (*tp
))))
1785 *tp
= build3 (BIT_FIELD_REF
, TREE_TYPE (*tp
), sym
,
1786 TYPE_SIZE (TREE_TYPE (*tp
)),
1787 int_const_binop (MULT_EXPR
,
1788 bitsize_int (BITS_PER_UNIT
),
1789 TREE_OPERAND (*tp
, 1)));
1791 else if (TREE_CODE (TREE_TYPE (sym
)) == COMPLEX_TYPE
1792 && useless_type_conversion_p (TREE_TYPE (*tp
),
1793 TREE_TYPE (TREE_TYPE (sym
))))
1795 *tp
= build1 (integer_zerop (TREE_OPERAND (*tp
, 1))
1796 ? REALPART_EXPR
: IMAGPART_EXPR
,
1797 TREE_TYPE (*tp
), sym
);
1799 else if (integer_zerop (TREE_OPERAND (*tp
, 1)))
1801 if (!useless_type_conversion_p (TREE_TYPE (*tp
),
1803 *tp
= build1 (VIEW_CONVERT_EXPR
,
1804 TREE_TYPE (*tp
), sym
);
1811 /* For a tree REF return its base if it is the base of a MEM_REF
1812 that cannot be rewritten into SSA form. Otherwise return NULL_TREE. */
1815 non_rewritable_mem_ref_base (tree ref
)
1819 /* A plain decl does not need it set. */
1823 while (handled_component_p (base
))
1824 base
= TREE_OPERAND (base
, 0);
1826 /* But watch out for MEM_REFs we cannot lower to a
1827 VIEW_CONVERT_EXPR or a BIT_FIELD_REF. */
1828 if (TREE_CODE (base
) == MEM_REF
1829 && TREE_CODE (TREE_OPERAND (base
, 0)) == ADDR_EXPR
)
1831 tree decl
= TREE_OPERAND (TREE_OPERAND (base
, 0), 0);
1832 if ((TREE_CODE (TREE_TYPE (decl
)) == VECTOR_TYPE
1833 || TREE_CODE (TREE_TYPE (decl
)) == COMPLEX_TYPE
)
1834 && useless_type_conversion_p (TREE_TYPE (base
),
1835 TREE_TYPE (TREE_TYPE (decl
)))
1836 && mem_ref_offset (base
).fits_uhwi ()
1837 && tree_to_double_int (TYPE_SIZE_UNIT (TREE_TYPE (decl
)))
1838 .ugt (mem_ref_offset (base
))
1839 && multiple_of_p (sizetype
, TREE_OPERAND (base
, 1),
1840 TYPE_SIZE_UNIT (TREE_TYPE (base
))))
1843 && (!integer_zerop (TREE_OPERAND (base
, 1))
1844 || (DECL_SIZE (decl
)
1845 != TYPE_SIZE (TREE_TYPE (base
)))
1846 || TREE_THIS_VOLATILE (decl
) != TREE_THIS_VOLATILE (base
)))
1853 /* For an lvalue tree LHS return true if it cannot be rewritten into SSA form.
1854 Otherwise return true. */
1857 non_rewritable_lvalue_p (tree lhs
)
1859 /* A plain decl is always rewritable. */
1863 /* A decl that is wrapped inside a MEM-REF that covers
1864 it full is also rewritable.
1865 ??? The following could be relaxed allowing component
1866 references that do not change the access size. */
1867 if (TREE_CODE (lhs
) == MEM_REF
1868 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == ADDR_EXPR
1869 && integer_zerop (TREE_OPERAND (lhs
, 1)))
1871 tree decl
= TREE_OPERAND (TREE_OPERAND (lhs
, 0), 0);
1873 && DECL_SIZE (decl
) == TYPE_SIZE (TREE_TYPE (lhs
))
1874 && (TREE_THIS_VOLATILE (decl
) == TREE_THIS_VOLATILE (lhs
)))
1881 /* When possible, clear TREE_ADDRESSABLE bit or set DECL_GIMPLE_REG_P bit and
1882 mark the variable VAR for conversion into SSA. Return true when updating
1883 stmts is required. */
1886 maybe_optimize_var (tree var
, bitmap addresses_taken
, bitmap not_reg_needs
,
1887 bitmap suitable_for_renaming
)
1889 /* Global Variables, result decls cannot be changed. */
1890 if (is_global_var (var
)
1891 || TREE_CODE (var
) == RESULT_DECL
1892 || bitmap_bit_p (addresses_taken
, DECL_UID (var
)))
1895 if (TREE_ADDRESSABLE (var
)
1896 /* Do not change TREE_ADDRESSABLE if we need to preserve var as
1897 a non-register. Otherwise we are confused and forget to
1898 add virtual operands for it. */
1899 && (!is_gimple_reg_type (TREE_TYPE (var
))
1900 || TREE_CODE (TREE_TYPE (var
)) == VECTOR_TYPE
1901 || TREE_CODE (TREE_TYPE (var
)) == COMPLEX_TYPE
1902 || !bitmap_bit_p (not_reg_needs
, DECL_UID (var
))))
1904 TREE_ADDRESSABLE (var
) = 0;
1905 if (is_gimple_reg (var
))
1906 bitmap_set_bit (suitable_for_renaming
, DECL_UID (var
));
1909 fprintf (dump_file
, "No longer having address taken: ");
1910 print_generic_expr (dump_file
, var
, 0);
1911 fprintf (dump_file
, "\n");
1915 if (!DECL_GIMPLE_REG_P (var
)
1916 && !bitmap_bit_p (not_reg_needs
, DECL_UID (var
))
1917 && (TREE_CODE (TREE_TYPE (var
)) == COMPLEX_TYPE
1918 || TREE_CODE (TREE_TYPE (var
)) == VECTOR_TYPE
)
1919 && !TREE_THIS_VOLATILE (var
)
1920 && (TREE_CODE (var
) != VAR_DECL
|| !DECL_HARD_REGISTER (var
)))
1922 DECL_GIMPLE_REG_P (var
) = 1;
1923 bitmap_set_bit (suitable_for_renaming
, DECL_UID (var
));
1926 fprintf (dump_file
, "Now a gimple register: ");
1927 print_generic_expr (dump_file
, var
, 0);
1928 fprintf (dump_file
, "\n");
1933 /* Compute TREE_ADDRESSABLE and DECL_GIMPLE_REG_P for local variables. */
1936 execute_update_addresses_taken (void)
1938 gimple_stmt_iterator gsi
;
1940 bitmap addresses_taken
= BITMAP_ALLOC (NULL
);
1941 bitmap not_reg_needs
= BITMAP_ALLOC (NULL
);
1942 bitmap suitable_for_renaming
= BITMAP_ALLOC (NULL
);
1946 timevar_push (TV_ADDRESS_TAKEN
);
1948 /* Collect into ADDRESSES_TAKEN all variables whose address is taken within
1949 the function body. */
1952 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1954 gimple stmt
= gsi_stmt (gsi
);
1955 enum gimple_code code
= gimple_code (stmt
);
1958 /* Note all addresses taken by the stmt. */
1959 gimple_ior_addresses_taken (addresses_taken
, stmt
);
1961 /* If we have a call or an assignment, see if the lhs contains
1962 a local decl that requires not to be a gimple register. */
1963 if (code
== GIMPLE_ASSIGN
|| code
== GIMPLE_CALL
)
1965 tree lhs
= gimple_get_lhs (stmt
);
1967 && TREE_CODE (lhs
) != SSA_NAME
1968 && non_rewritable_lvalue_p (lhs
))
1970 decl
= get_base_address (lhs
);
1972 bitmap_set_bit (not_reg_needs
, DECL_UID (decl
));
1976 if (gimple_assign_single_p (stmt
))
1978 tree rhs
= gimple_assign_rhs1 (stmt
);
1979 if ((decl
= non_rewritable_mem_ref_base (rhs
)))
1980 bitmap_set_bit (not_reg_needs
, DECL_UID (decl
));
1983 else if (code
== GIMPLE_CALL
)
1985 for (i
= 0; i
< gimple_call_num_args (stmt
); ++i
)
1987 tree arg
= gimple_call_arg (stmt
, i
);
1988 if ((decl
= non_rewritable_mem_ref_base (arg
)))
1989 bitmap_set_bit (not_reg_needs
, DECL_UID (decl
));
1993 else if (code
== GIMPLE_ASM
)
1995 for (i
= 0; i
< gimple_asm_noutputs (stmt
); ++i
)
1997 tree link
= gimple_asm_output_op (stmt
, i
);
1998 tree lhs
= TREE_VALUE (link
);
1999 if (TREE_CODE (lhs
) != SSA_NAME
)
2001 decl
= get_base_address (lhs
);
2003 && (non_rewritable_lvalue_p (lhs
)
2004 /* We cannot move required conversions from
2005 the lhs to the rhs in asm statements, so
2006 require we do not need any. */
2007 || !useless_type_conversion_p
2008 (TREE_TYPE (lhs
), TREE_TYPE (decl
))))
2009 bitmap_set_bit (not_reg_needs
, DECL_UID (decl
));
2012 for (i
= 0; i
< gimple_asm_ninputs (stmt
); ++i
)
2014 tree link
= gimple_asm_input_op (stmt
, i
);
2015 if ((decl
= non_rewritable_mem_ref_base (TREE_VALUE (link
))))
2016 bitmap_set_bit (not_reg_needs
, DECL_UID (decl
));
2021 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
2024 gimple phi
= gsi_stmt (gsi
);
2026 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
2028 tree op
= PHI_ARG_DEF (phi
, i
), var
;
2029 if (TREE_CODE (op
) == ADDR_EXPR
2030 && (var
= get_base_address (TREE_OPERAND (op
, 0))) != NULL
2032 bitmap_set_bit (addresses_taken
, DECL_UID (var
));
2037 /* We cannot iterate over all referenced vars because that can contain
2038 unused vars from BLOCK trees, which causes code generation differences
2040 for (var
= DECL_ARGUMENTS (cfun
->decl
); var
; var
= DECL_CHAIN (var
))
2041 maybe_optimize_var (var
, addresses_taken
, not_reg_needs
,
2042 suitable_for_renaming
);
2044 FOR_EACH_VEC_SAFE_ELT (cfun
->local_decls
, i
, var
)
2045 maybe_optimize_var (var
, addresses_taken
, not_reg_needs
,
2046 suitable_for_renaming
);
2048 /* Operand caches need to be recomputed for operands referencing the updated
2049 variables and operands need to be rewritten to expose bare symbols. */
2050 if (!bitmap_empty_p (suitable_for_renaming
))
2053 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
);)
2055 gimple stmt
= gsi_stmt (gsi
);
2057 /* Re-write TARGET_MEM_REFs of symbols we want to
2058 rewrite into SSA form. */
2059 if (gimple_assign_single_p (stmt
))
2061 tree lhs
= gimple_assign_lhs (stmt
);
2062 tree rhs
, *rhsp
= gimple_assign_rhs1_ptr (stmt
);
2065 /* We shouldn't have any fancy wrapping of
2066 component-refs on the LHS, but look through
2067 VIEW_CONVERT_EXPRs as that is easy. */
2068 while (TREE_CODE (lhs
) == VIEW_CONVERT_EXPR
)
2069 lhs
= TREE_OPERAND (lhs
, 0);
2070 if (TREE_CODE (lhs
) == MEM_REF
2071 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == ADDR_EXPR
2072 && integer_zerop (TREE_OPERAND (lhs
, 1))
2073 && (sym
= TREE_OPERAND (TREE_OPERAND (lhs
, 0), 0))
2075 && !TREE_ADDRESSABLE (sym
)
2076 && bitmap_bit_p (suitable_for_renaming
, DECL_UID (sym
)))
2079 lhs
= gimple_assign_lhs (stmt
);
2081 /* Rewrite the RHS and make sure the resulting assignment
2082 is validly typed. */
2083 maybe_rewrite_mem_ref_base (rhsp
, suitable_for_renaming
);
2084 rhs
= gimple_assign_rhs1 (stmt
);
2085 if (gimple_assign_lhs (stmt
) != lhs
2086 && !useless_type_conversion_p (TREE_TYPE (lhs
),
2088 rhs
= fold_build1 (VIEW_CONVERT_EXPR
,
2089 TREE_TYPE (lhs
), rhs
);
2091 if (gimple_assign_lhs (stmt
) != lhs
)
2092 gimple_assign_set_lhs (stmt
, lhs
);
2094 /* For var ={v} {CLOBBER}; where var lost
2095 TREE_ADDRESSABLE just remove the stmt. */
2097 && TREE_CLOBBER_P (rhs
)
2098 && bitmap_bit_p (suitable_for_renaming
, DECL_UID (lhs
)))
2100 unlink_stmt_vdef (stmt
);
2101 gsi_remove (&gsi
, true);
2102 release_defs (stmt
);
2106 if (gimple_assign_rhs1 (stmt
) != rhs
)
2108 gimple_stmt_iterator gsi
= gsi_for_stmt (stmt
);
2109 gimple_assign_set_rhs_from_tree (&gsi
, rhs
);
2113 else if (gimple_code (stmt
) == GIMPLE_CALL
)
2116 for (i
= 0; i
< gimple_call_num_args (stmt
); ++i
)
2118 tree
*argp
= gimple_call_arg_ptr (stmt
, i
);
2119 maybe_rewrite_mem_ref_base (argp
, suitable_for_renaming
);
2123 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2126 for (i
= 0; i
< gimple_asm_noutputs (stmt
); ++i
)
2128 tree link
= gimple_asm_output_op (stmt
, i
);
2129 maybe_rewrite_mem_ref_base (&TREE_VALUE (link
),
2130 suitable_for_renaming
);
2132 for (i
= 0; i
< gimple_asm_ninputs (stmt
); ++i
)
2134 tree link
= gimple_asm_input_op (stmt
, i
);
2135 maybe_rewrite_mem_ref_base (&TREE_VALUE (link
),
2136 suitable_for_renaming
);
2140 else if (gimple_debug_bind_p (stmt
)
2141 && gimple_debug_bind_has_value_p (stmt
))
2143 tree
*valuep
= gimple_debug_bind_get_value_ptr (stmt
);
2145 maybe_rewrite_mem_ref_base (valuep
, suitable_for_renaming
);
2146 decl
= non_rewritable_mem_ref_base (*valuep
);
2148 && bitmap_bit_p (suitable_for_renaming
, DECL_UID (decl
)))
2149 gimple_debug_bind_reset_value (stmt
);
2152 if (gimple_references_memory_p (stmt
)
2153 || is_gimple_debug (stmt
))
2159 /* Update SSA form here, we are called as non-pass as well. */
2160 if (number_of_loops () > 1 && loops_state_satisfies_p (LOOP_CLOSED_SSA
))
2161 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
2163 update_ssa (TODO_update_ssa
);
2166 BITMAP_FREE (not_reg_needs
);
2167 BITMAP_FREE (addresses_taken
);
2168 BITMAP_FREE (suitable_for_renaming
);
2169 timevar_pop (TV_ADDRESS_TAKEN
);
2172 struct gimple_opt_pass pass_update_address_taken
=
2176 "addressables", /* name */
2177 OPTGROUP_NONE
, /* optinfo_flags */
2182 0, /* static_pass_number */
2183 TV_ADDRESS_TAKEN
, /* tv_id */
2184 PROP_ssa
, /* properties_required */
2185 0, /* properties_provided */
2186 0, /* properties_destroyed */
2187 0, /* todo_flags_start */
2188 TODO_update_address_taken
/* todo_flags_finish */