1 /* Data and Control Flow Analysis for Trees.
2    Copyright (C) 2001, 2003, 2004, 2005 Free Software Foundation, Inc.
3    Contributed by Diego Novillo <dnovillo@redhat.com>
4 
5 This file is part of GCC.
6 
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 2, or (at your option)
10 any later version.
11 
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 GNU General Public License for more details.
16 
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING.  If not, write to
19 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA.  */
21 
22 #ifndef _TREE_FLOW_H
23 #define _TREE_FLOW_H 1
24 
25 #include "bitmap.h"
26 #include "hard-reg-set.h"
27 #include "basic-block.h"
28 #include "hashtab.h"
29 #include "tree-gimple.h"
30 #include "tree-ssa-operands.h"
31 #include "cgraph.h"
32 #include "ipa-reference.h"
33 
34 /* Forward declare structures for the garbage collector GTY markers.  */
35 #ifndef GCC_BASIC_BLOCK_H
36 struct edge_def;
37 typedef struct edge_def *edge;
38 struct basic_block_def;
39 typedef struct basic_block_def *basic_block;
40 #endif
41 
42 /* True if the code is in ssa form.  */
43 extern bool in_ssa_p;
44 
45 typedef struct
46 {
47   htab_t htab;
48   PTR *slot;
49   PTR *limit;
50 } htab_iterator;
51 
52 /* Iterate through the elements of hashtable HTAB, using htab_iterator ITER,
53    storing each element in RESULT, which is of type TYPE.  */
54 #define FOR_EACH_HTAB_ELEMENT(HTAB, RESULT, TYPE, ITER) \
55   for (RESULT = (TYPE) first_htab_element (&(ITER), (HTAB)); \
56 	!end_htab_p (&(ITER)); \
57 	RESULT = (TYPE) next_htab_element (&(ITER)))
58 
59 /*---------------------------------------------------------------------------
60 		      Attributes for SSA_NAMEs.
61 
62   NOTE: These structures are stored in struct tree_ssa_name
63   but are only used by the tree optimizers, so it makes better sense
64   to declare them here to avoid recompiling unrelated files when
65   making changes.
66 ---------------------------------------------------------------------------*/
67 
68 /* Aliasing information for SSA_NAMEs representing pointer variables.  */
69 struct ptr_info_def GTY(())
70 {
71   /* Nonzero if points-to analysis couldn't determine where this pointer
72      is pointing to.  */
73   unsigned int pt_anything : 1;
74 
75   /* Nonzero if the value of this pointer escapes the current function.  */
76   unsigned int value_escapes_p : 1;
77 
78   /* Nonzero if this pointer is dereferenced.  */
79   unsigned int is_dereferenced : 1;
80 
81   /* Nonzero if this pointer points to a global variable.  */
82   unsigned int pt_global_mem : 1;
83 
84   /* Nonzero if this pointer points to NULL.  */
85   unsigned int pt_null : 1;
86 
87   /* Set of variables that this pointer may point to.  */
88   bitmap pt_vars;
89 
90   /* If this pointer has been dereferenced, and points-to information is
91      more precise than type-based aliasing, indirect references to this
92      pointer will be represented by this memory tag, instead of the type
93      tag computed by TBAA.  */
94   tree name_mem_tag;
95 };
96 
97 
98 /*---------------------------------------------------------------------------
99 		   Tree annotations stored in tree_common.ann
100 ---------------------------------------------------------------------------*/
101 enum tree_ann_type { TREE_ANN_COMMON, VAR_ANN, STMT_ANN };
102 
103 struct tree_ann_common_d GTY(())
104 {
105   /* Annotation type.  */
106   enum tree_ann_type type;
107 
108  /* Auxiliary info specific to a pass.  At all times, this
109     should either point to valid data or be NULL.  */
110   PTR GTY ((skip (""))) aux;
111 
112   /* The value handle for this expression.  Used by GVN-PRE.  */
113   tree GTY((skip)) value_handle;
114 };
115 
116 /* It is advantageous to avoid things like life analysis for variables which
117    do not need PHI nodes.  This enum describes whether or not a particular
118    variable may need a PHI node.  */
119 
120 enum need_phi_state {
121   /* This is the default.  If we are still in this state after finding
122      all the definition and use sites, then we will assume the variable
123      needs PHI nodes.  This is probably an overly conservative assumption.  */
124   NEED_PHI_STATE_UNKNOWN,
125 
126   /* This state indicates that we have seen one or more sets of the
127      variable in a single basic block and that the sets dominate all
128      uses seen so far.  If after finding all definition and use sites
129      we are still in this state, then the variable does not need any
130      PHI nodes.  */
131   NEED_PHI_STATE_NO,
132 
133   /* This state indicates that we have either seen multiple definitions of
134      the variable in multiple blocks, or that we encountered a use in a
135      block that was not dominated by the block containing the set(s) of
136      this variable.  This variable is assumed to need PHI nodes.  */
137   NEED_PHI_STATE_MAYBE
138 };
139 
140 
141 /* When computing aliasing information, we represent the memory pointed-to
142    by pointers with artificial variables called "memory tags" (MT).  There
143    are two kinds of tags: type and name.  Type tags (TMT) are used in
144    type-based alias analysis, they represent all the pointed-to locations
145    and variables of the same alias set class.  Name tags (NMT) are used in
146    flow-sensitive points-to alias analysis, they represent the variables
147    and memory locations pointed-to by a specific SSA_NAME pointer.  */
148 enum mem_tag_kind {
149   /* This variable is not a memory tag.  */
150   NOT_A_TAG,
151 
152   /* This variable is a type memory tag (TMT).  */
153   TYPE_TAG,
154 
155   /* This variable is a name memory tag (NMT).  */
156   NAME_TAG,
157 
158   /* This variable represents a structure field.  */
159   STRUCT_FIELD
160 };
161 
162 struct subvar;
163 typedef struct subvar *subvar_t;
164 
165 /* This structure represents a fake sub-variable for a structure field.  */
166 struct subvar GTY(())
167 {
168   /* Fake variable.  */
169   tree var;
170 
171   /* Offset inside structure.  */
172   unsigned HOST_WIDE_INT offset;
173 
174   /* Size of the field.  */
175   unsigned HOST_WIDE_INT size;
176 
177   /* Next subvar for this structure.  */
178   subvar_t next;
179 };
180 
181 struct var_ann_d GTY(())
182 {
183   struct tree_ann_common_d common;
184 
185   /* Used by the out of SSA pass to determine whether this variable has
186      been seen yet or not.  */
187   unsigned out_of_ssa_tag : 1;
188 
189   /* Used when building root_var structures in tree_ssa_live.[ch].  */
190   unsigned root_var_processed : 1;
191 
192   /* If nonzero, this variable is a memory tag.  */
193   ENUM_BITFIELD (mem_tag_kind) mem_tag_kind : 2;
194 
195   /* Nonzero if this variable is an alias tag that represents references to
196      other variables (i.e., this variable appears in the MAY_ALIASES array
197      of other variables).  */
198   unsigned is_alias_tag : 1;
199 
200   /* Nonzero if this variable was used after SSA optimizations were
201      applied.  We set this when translating out of SSA form.  */
202   unsigned used : 1;
203 
204   /* This field indicates whether or not the variable may need PHI nodes.
205      See the enum's definition for more detailed information about the
206      states.  */
207   ENUM_BITFIELD (need_phi_state) need_phi_state : 2;
208 
209   /* Used during operand processing to determine if this variable is already
210      in the vuse list.  */
211   unsigned in_vuse_list : 1;
212 
213   /* Used during operand processing to determine if this variable is already
214      in the v_may_def list.  */
215   unsigned in_v_may_def_list : 1;
216 
217   /* An artificial variable representing the memory location pointed-to by
218      all the pointers that TBAA (type-based alias analysis) considers
219      to be aliased.  If the variable is not a pointer or if it is never
220      dereferenced, this must be NULL.  */
221   tree type_mem_tag;
222 
223   /* Variables that may alias this variable.  */
224   varray_type may_aliases;
225 
226   /* Used when going out of SSA form to indicate which partition this
227      variable represents storage for.  */
228   unsigned partition;
229 
230   /* Used by the root-var object in tree-ssa-live.[ch].  */
231   unsigned root_index;
232 
233   /* Default definition for this symbol.  If this field is not NULL, it
234      means that the first reference to this variable in the function is a
235      USE or a VUSE.  In those cases, the SSA renamer creates an SSA name
236      for this variable with an empty defining statement.  */
237   tree default_def;
238 
239   /* During into-ssa and the dominator optimizer, this field holds the
240      current version of this variable (an SSA_NAME).  */
241   tree current_def;
242 
243   /* Pointer to the structure that contains the sets of global
244      variables modified by function calls.  This field is only used
245      for FUNCTION_DECLs.  */
246   ipa_reference_vars_info_t GTY ((skip)) reference_vars_info;
247 
248   /* If this variable is a structure, this fields holds a list of
249      symbols representing each of the fields of the structure.  */
250   subvar_t subvars;
251 };
252 
253 
254 typedef struct immediate_use_iterator_d
255 {
256   ssa_use_operand_t *imm_use;
257   ssa_use_operand_t *end_p;
258   ssa_use_operand_t iter_node;
259 } imm_use_iterator;
260 
261 
262 /* Use this iterator when simply looking at stmts.  Adding, deleting or
263    modifying stmts will cause this iterator to malfunction.  */
264 
265 #define FOR_EACH_IMM_USE_FAST(DEST, ITER, SSAVAR)			\
266   for ((DEST) = first_readonly_imm_use (&(ITER), (SSAVAR));	\
267        !end_readonly_imm_use_p (&(ITER));			\
268        (DEST) = next_readonly_imm_use (&(ITER)))
269 
270 
271 #define FOR_EACH_IMM_USE_SAFE(DEST, ITER, SSAVAR)		\
272   for ((DEST) = first_safe_imm_use (&(ITER), (SSAVAR));		\
273        !end_safe_imm_use_p (&(ITER));				\
274        (DEST) = next_safe_imm_use (&(ITER)))
275 
276 #define BREAK_FROM_SAFE_IMM_USE(ITER)				\
277    {								\
278      end_safe_imm_use_traverse (&(ITER));			\
279      break;							\
280    }
281 
282 struct stmt_ann_d GTY(())
283 {
284   struct tree_ann_common_d common;
285 
286   /* Nonzero if the statement has been modified (meaning that the operands
287      need to be scanned again).  */
288   unsigned modified : 1;
289 
290   /* Nonzero if the statement makes aliased loads.  */
291   unsigned makes_aliased_loads : 1;
292 
293   /* Nonzero if the statement makes aliased stores.  */
294   unsigned makes_aliased_stores : 1;
295 
296   /* Nonzero if the statement makes references to volatile storage.  */
297   unsigned has_volatile_ops : 1;
298 
299   /* Nonzero if the statement makes a function call that may clobber global
300      and local addressable variables.  */
301   unsigned makes_clobbering_call : 1;
302 
303   /* Basic block that contains this statement.  */
304   basic_block bb;
305 
306   /* Operand cache for stmt.  */
307   struct stmt_operands_d GTY ((skip (""))) operands;
308 
309   /* Set of variables that have had their address taken in the statement.  */
310   bitmap addresses_taken;
311 
312   /* Unique identifier for this statement.  These ID's are to be created
313      by each pass on an as-needed basis in any order convenient for the
314      pass which needs statement UIDs.  */
315   unsigned int uid;
316 
317   /* Linked list of histograms for value-based profiling.  This is really a
318      struct histogram_value*.  We use void* to avoid having to export that
319      everywhere, and to avoid having to put it in GC memory.  */
320 
321   void * GTY ((skip (""))) histograms;
322 };
323 
324 union tree_ann_d GTY((desc ("ann_type ((tree_ann_t)&%h)")))
325 {
326   struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
327   struct var_ann_d GTY((tag ("VAR_ANN"))) decl;
328   struct stmt_ann_d GTY((tag ("STMT_ANN"))) stmt;
329 };
330 
331 extern GTY(()) VEC(tree,gc) *modified_noreturn_calls;
332 
333 typedef union tree_ann_d *tree_ann_t;
334 typedef struct var_ann_d *var_ann_t;
335 typedef struct stmt_ann_d *stmt_ann_t;
336 
337 static inline tree_ann_t tree_ann (tree);
338 static inline tree_ann_t get_tree_ann (tree);
339 static inline var_ann_t var_ann (tree);
340 static inline var_ann_t get_var_ann (tree);
341 static inline stmt_ann_t stmt_ann (tree);
342 static inline stmt_ann_t get_stmt_ann (tree);
343 static inline enum tree_ann_type ann_type (tree_ann_t);
344 static inline basic_block bb_for_stmt (tree);
345 extern void set_bb_for_stmt (tree, basic_block);
346 static inline bool noreturn_call_p (tree);
347 static inline void update_stmt (tree);
348 static inline bool stmt_modified_p (tree);
349 static inline varray_type may_aliases (tree);
350 static inline int get_lineno (tree);
351 static inline const char *get_filename (tree);
352 static inline bool is_exec_stmt (tree);
353 static inline bool is_label_stmt (tree);
354 static inline bitmap addresses_taken (tree);
355 static inline void set_default_def (tree, tree);
356 static inline tree default_def (tree);
357 
358 /*---------------------------------------------------------------------------
359                   Structure representing predictions in tree level.
360 ---------------------------------------------------------------------------*/
361 struct edge_prediction GTY((chain_next ("%h.next")))
362 {
363   struct edge_prediction *next;
364   edge edge;
365   enum br_predictor predictor;
366   int probability;
367 };
368 
369 /* Accessors for basic block annotations.  */
370 static inline tree phi_nodes (basic_block);
371 static inline void set_phi_nodes (basic_block, tree);
372 
373 /*---------------------------------------------------------------------------
374 			      Global declarations
375 ---------------------------------------------------------------------------*/
376 struct int_tree_map GTY(())
377 {
378 
379   unsigned int uid;
380   tree to;
381 };
382 
383 extern unsigned int int_tree_map_hash (const void *);
384 extern int int_tree_map_eq (const void *, const void *);
385 
386 typedef struct
387 {
388   htab_iterator hti;
389 } referenced_var_iterator;
390 
391 
392 /* This macro loops over all the referenced vars, one at a time, putting the
393    current var in VAR.  Note:  You are not allowed to add referenced variables
394    to the hashtable while using this macro.  Doing so may cause it to behave
395    erratically.  */
396 
397 #define FOR_EACH_REFERENCED_VAR(VAR, ITER) \
398   for ((VAR) = first_referenced_var (&(ITER)); \
399        !end_referenced_vars_p (&(ITER)); \
400        (VAR) = next_referenced_var (&(ITER)))
401 
402 
403 typedef struct
404 {
405   int i;
406 } safe_referenced_var_iterator;
407 
408 /* This macro loops over all the referenced vars, one at a time, putting the
409    current var in VAR.  You are allowed to add referenced variables during the
410    execution of this macro, however, the macro will not iterate over them.  It
411    requires a temporary vector of trees, VEC, whose lifetime is controlled by
412    the caller.  The purpose of the vector is to temporarily store the
413    referenced_variables hashtable so that adding referenced variables does not
414    affect the hashtable.  */
415 
416 #define FOR_EACH_REFERENCED_VAR_SAFE(VAR, VEC, ITER) \
417   for ((ITER).i = 0, fill_referenced_var_vec (&(VEC)); \
418        VEC_iterate (tree, (VEC), (ITER).i, (VAR)); \
419        (ITER).i++)
420 
421 /* Array of all variables referenced in the function.  */
422 extern GTY((param_is (struct int_tree_map))) htab_t referenced_vars;
423 /* List of referenced variables in the function with duplicate UID's.  */
424 extern VEC(tree,gc) *referenced_vars_dup_list;
425 
426 extern tree referenced_var_lookup (unsigned int);
427 extern tree referenced_var_lookup_if_exists (unsigned int);
428 #define num_referenced_vars htab_elements (referenced_vars)
429 #define referenced_var(i) referenced_var_lookup (i)
430 
431 /* Array of all SSA_NAMEs used in the function.  */
432 extern GTY(()) VEC(tree,gc) *ssa_names;
433 
434 #define num_ssa_names (VEC_length (tree, ssa_names))
435 #define ssa_name(i) (VEC_index (tree, ssa_names, (i)))
436 
437 /* Artificial variable used to model the effects of function calls.  */
438 extern GTY(()) tree global_var;
439 
440 /* Call clobbered variables in the function.  If bit I is set, then
441    REFERENCED_VARS (I) is call-clobbered.  */
442 extern bitmap call_clobbered_vars;
443 
444 /* Addressable variables in the function.  If bit I is set, then
445    REFERENCED_VARS (I) has had its address taken.  */
446 extern bitmap addressable_vars;
447 
448 /* 'true' after aliases have been computed (see compute_may_aliases).  */
449 extern bool aliases_computed_p;
450 
451 /* Macros for showing usage statistics.  */
452 #define SCALE(x) ((unsigned long) ((x) < 1024*10	\
453 		  ? (x)					\
454 		  : ((x) < 1024*1024*10			\
455 		     ? (x) / 1024			\
456 		     : (x) / (1024*1024))))
457 
458 #define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
459 
460 #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
461 
462 /*---------------------------------------------------------------------------
463 			      Block iterators
464 ---------------------------------------------------------------------------*/
465 
466 typedef struct {
467   tree_stmt_iterator tsi;
468   basic_block bb;
469 } block_stmt_iterator;
470 
471 static inline block_stmt_iterator bsi_start (basic_block);
472 static inline block_stmt_iterator bsi_last (basic_block);
473 static inline block_stmt_iterator bsi_after_labels (basic_block);
474 block_stmt_iterator bsi_for_stmt (tree);
475 static inline bool bsi_end_p (block_stmt_iterator);
476 static inline void bsi_next (block_stmt_iterator *);
477 static inline void bsi_prev (block_stmt_iterator *);
478 static inline tree bsi_stmt (block_stmt_iterator);
479 static inline tree * bsi_stmt_ptr (block_stmt_iterator);
480 
481 extern void bsi_remove (block_stmt_iterator *);
482 extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
483 extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
484 extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
485 
486 enum bsi_iterator_update
487 {
488   /* Note that these are intentionally in the same order as TSI_FOO.  They
489      mean exactly the same as their TSI_* counterparts.  */
490   BSI_NEW_STMT,
491   BSI_SAME_STMT,
492   BSI_CHAIN_START,
493   BSI_CHAIN_END,
494   BSI_CONTINUE_LINKING
495 };
496 
497 extern void bsi_insert_before (block_stmt_iterator *, tree,
498 			       enum bsi_iterator_update);
499 extern void bsi_insert_after (block_stmt_iterator *, tree,
500 			      enum bsi_iterator_update);
501 
502 extern void bsi_replace (const block_stmt_iterator *, tree, bool);
503 
504 /*---------------------------------------------------------------------------
505 			      Function prototypes
506 ---------------------------------------------------------------------------*/
507 /* In tree-cfg.c  */
508 
509 /* Location to track pending stmt for edge insertion.  */
510 #define PENDING_STMT(e)	((e)->insns.t)
511 
512 extern void delete_tree_cfg_annotations (void);
513 extern void disband_implicit_edges (void);
514 extern bool stmt_ends_bb_p (tree);
515 extern bool is_ctrl_stmt (tree);
516 extern bool is_ctrl_altering_stmt (tree);
517 extern bool computed_goto_p (tree);
518 extern bool simple_goto_p (tree);
519 extern basic_block single_noncomplex_succ (basic_block bb);
520 extern void tree_dump_bb (basic_block, FILE *, int);
521 extern void debug_tree_bb (basic_block);
522 extern basic_block debug_tree_bb_n (int);
523 extern void dump_tree_cfg (FILE *, int);
524 extern void debug_tree_cfg (int);
525 extern void dump_cfg_stats (FILE *);
526 extern void debug_cfg_stats (void);
527 extern void debug_loop_ir (void);
528 extern void print_loop_ir (FILE *);
529 extern void cleanup_dead_labels (void);
530 extern void group_case_labels (void);
531 extern tree first_stmt (basic_block);
532 extern tree last_stmt (basic_block);
533 extern tree *last_stmt_ptr (basic_block);
534 extern tree last_and_only_stmt (basic_block);
535 extern edge find_taken_edge (basic_block, tree);
536 extern basic_block label_to_block_fn (struct function *, tree);
537 #define label_to_block(t) (label_to_block_fn (cfun, t))
538 extern void bsi_insert_on_edge (edge, tree);
539 extern basic_block bsi_insert_on_edge_immediate (edge, tree);
540 extern void bsi_commit_one_edge_insert (edge, basic_block *);
541 extern void bsi_commit_edge_inserts (void);
542 extern void notice_special_calls (tree);
543 extern void clear_special_calls (void);
544 extern void verify_stmts (void);
545 extern tree tree_block_label (basic_block);
546 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
547 extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
548 					basic_block *);
549 extern void add_phi_args_after_copy_bb (basic_block);
550 extern void add_phi_args_after_copy (basic_block *, unsigned);
551 extern bool tree_purge_dead_eh_edges (basic_block);
552 extern bool tree_purge_all_dead_eh_edges (bitmap);
553 extern tree gimplify_val (block_stmt_iterator *, tree, tree);
554 extern tree gimplify_build1 (block_stmt_iterator *, enum tree_code,
555 			     tree, tree);
556 extern tree gimplify_build2 (block_stmt_iterator *, enum tree_code,
557 			     tree, tree, tree);
558 extern tree gimplify_build3 (block_stmt_iterator *, enum tree_code,
559 			     tree, tree, tree, tree);
560 extern void init_empty_tree_cfg (void);
561 extern void fold_cond_expr_cond (void);
562 extern void replace_uses_by (tree, tree);
563 extern void start_recording_case_labels (void);
564 extern void end_recording_case_labels (void);
565 
566 /* In tree-cfgcleanup.c  */
567 extern bool cleanup_tree_cfg (void);
568 extern void cleanup_tree_cfg_loop (void);
569 
570 /* In tree-pretty-print.c.  */
571 extern void dump_generic_bb (FILE *, basic_block, int, int);
572 
573 /* In tree-dfa.c  */
574 extern var_ann_t create_var_ann (tree);
575 extern stmt_ann_t create_stmt_ann (tree);
576 extern tree_ann_t create_tree_ann (tree);
577 extern void dump_dfa_stats (FILE *);
578 extern void debug_dfa_stats (void);
579 extern void debug_referenced_vars (void);
580 extern void dump_referenced_vars (FILE *);
581 extern void dump_variable (FILE *, tree);
582 extern void debug_variable (tree);
583 extern void dump_subvars_for (FILE *, tree);
584 extern void debug_subvars_for (tree);
585 extern tree get_virtual_var (tree);
586 extern void add_referenced_tmp_var (tree);
587 extern void mark_new_vars_to_rename (tree);
588 extern void find_new_referenced_vars (tree *);
589 
590 extern tree make_rename_temp (tree, const char *);
591 
592 /* In tree-phinodes.c  */
593 extern void reserve_phi_args_for_new_edge (basic_block);
594 extern tree create_phi_node (tree, basic_block);
595 extern void add_phi_arg (tree, tree, edge);
596 extern void remove_phi_args (edge);
597 extern void remove_phi_node (tree, tree);
598 extern tree phi_reverse (tree);
599 
600 /* In gimple-low.c  */
601 extern void record_vars (tree);
602 extern bool block_may_fallthru (tree block);
603 
604 /* In tree-ssa-alias.c  */
605 extern void dump_may_aliases_for (FILE *, tree);
606 extern void debug_may_aliases_for (tree);
607 extern void dump_alias_info (FILE *);
608 extern void debug_alias_info (void);
609 extern void dump_points_to_info (FILE *);
610 extern void debug_points_to_info (void);
611 extern void dump_points_to_info_for (FILE *, tree);
612 extern void debug_points_to_info_for (tree);
613 extern bool may_be_aliased (tree);
614 extern bool is_aliased_with (tree, tree);
615 extern struct ptr_info_def *get_ptr_info (tree);
616 extern void add_type_alias (tree, tree);
617 extern void new_type_alias (tree, tree);
618 extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *, bool *);
619 static inline subvar_t get_subvars_for_var (tree);
620 static inline tree get_subvar_at (tree, unsigned HOST_WIDE_INT);
621 static inline bool ref_contains_array_ref (tree);
622 static inline bool array_ref_contains_indirect_ref (tree);
623 extern tree okay_component_ref_for_subvars (tree, unsigned HOST_WIDE_INT *,
624 					    unsigned HOST_WIDE_INT *);
625 static inline bool var_can_have_subvars (tree);
626 static inline bool overlap_subvar (unsigned HOST_WIDE_INT,
627 				   unsigned HOST_WIDE_INT,
628 				   subvar_t, bool *);
629 
630 /* Call-back function for walk_use_def_chains().  At each reaching
631    definition, a function with this prototype is called.  */
632 typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
633 
634 
635 /* In tree-ssa.c  */
636 extern void init_tree_ssa (void);
637 extern edge ssa_redirect_edge (edge, basic_block);
638 extern void flush_pending_stmts (edge);
639 extern bool tree_ssa_useless_type_conversion (tree);
640 extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
641 extern void verify_ssa (bool);
642 extern void delete_tree_ssa (void);
643 extern void register_new_def (tree, VEC(tree,heap) **);
644 extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *, bool);
645 extern bool stmt_references_memory_p (tree);
646 
647 /* In tree-into-ssa.c  */
648 void update_ssa (unsigned);
649 void delete_update_ssa (void);
650 void register_new_name_mapping (tree, tree);
651 tree create_new_def_for (tree, tree, def_operand_p);
652 bool need_ssa_update_p (void);
653 bool name_registered_for_update_p (tree);
654 bitmap ssa_names_to_replace (void);
655 void release_ssa_name_after_update_ssa (tree name);
656 void compute_global_livein (bitmap, bitmap);
657 tree duplicate_ssa_name (tree, tree);
658 void mark_sym_for_renaming (tree);
659 void mark_set_for_renaming (bitmap);
660 tree get_current_def (tree);
661 void set_current_def (tree, tree);
662 
663 /* In tree-ssa-ccp.c  */
664 bool fold_stmt (tree *);
665 bool fold_stmt_inplace (tree);
666 tree widen_bitfield (tree, tree, tree);
667 
668 /* In tree-vrp.c  */
669 tree vrp_evaluate_conditional (tree, bool);
670 void simplify_stmt_using_ranges (tree);
671 
672 /* In tree-ssa-dom.c  */
673 extern void dump_dominator_optimization_stats (FILE *);
674 extern void debug_dominator_optimization_stats (void);
675 int loop_depth_of_name (tree);
676 
677 /* In tree-ssa-copy.c  */
678 extern void merge_alias_info (tree, tree);
679 extern void propagate_value (use_operand_p, tree);
680 extern void propagate_tree_value (tree *, tree);
681 extern void replace_exp (use_operand_p, tree);
682 extern bool may_propagate_copy (tree, tree);
683 extern bool may_propagate_copy_into_asm (tree);
684 
685 /* Description of number of iterations of a loop.  All the expressions inside
686    the structure can be evaluated at the end of the loop's preheader
687    (and due to ssa form, also anywhere inside the body of the loop).  */
688 
689 struct tree_niter_desc
690 {
691   tree assumptions;	/* The boolean expression.  If this expression evaluates
692 			   to false, then the other fields in this structure
693 			   should not be used; there is no guarantee that they
694 			   will be correct.  */
695   tree may_be_zero;	/* The boolean expression.  If it evaluates to true,
696 			   the loop will exit in the first iteration (i.e.
697 			   its latch will not be executed), even if the niter
698 			   field says otherwise.  */
699   tree niter;		/* The expression giving the number of iterations of
700 			   a loop (provided that assumptions == true and
701 			   may_be_zero == false), more precisely the number
702 			   of executions of the latch of the loop.  */
703   tree additional_info;	/* The boolean expression.  Sometimes we use additional
704 			   knowledge to simplify the other expressions
705 			   contained in this structure (for example the
706 			   knowledge about value ranges of operands on entry to
707 			   the loop).  If this is a case, conjunction of such
708 			   condition is stored in this field, so that we do not
709 			   lose the information: for example if may_be_zero
710 			   is (n <= 0) and niter is (unsigned) n, we know
711 			   that the number of iterations is at most
712 			   MAX_SIGNED_INT.  However if the (n <= 0) assumption
713 			   is eliminated (by looking at the guard on entry of
714 			   the loop), then the information would be lost.  */
715 };
716 
717 /* In tree-vectorizer.c */
718 void vectorize_loops (struct loops *);
719 
720 /* In tree-ssa-phiopt.c */
721 bool empty_block_p (basic_block);
722 
723 /* In tree-ssa-loop*.c  */
724 
725 void tree_ssa_lim (struct loops *);
726 void tree_ssa_unswitch_loops (struct loops *);
727 void canonicalize_induction_variables (struct loops *);
728 void tree_unroll_loops_completely (struct loops *, bool);
729 void remove_empty_loops (struct loops *);
730 void tree_ssa_iv_optimize (struct loops *);
731 
732 bool number_of_iterations_exit (struct loop *, edge,
733 				struct tree_niter_desc *niter, bool);
734 tree find_loop_niter (struct loop *, edge *);
735 tree loop_niter_by_eval (struct loop *, edge);
736 tree find_loop_niter_by_eval (struct loop *, edge *);
737 void estimate_numbers_of_iterations (struct loops *);
738 bool scev_probably_wraps_p (tree, tree, tree, struct loop *, bool);
739 bool convert_affine_scev (struct loop *, tree, tree *, tree *, tree, bool);
740 
741 bool nowrap_type_p (tree);
742 enum ev_direction {EV_DIR_GROWS, EV_DIR_DECREASES, EV_DIR_UNKNOWN};
743 enum ev_direction scev_direction (tree);
744 
745 void free_numbers_of_iterations_estimates (struct loops *);
746 void free_numbers_of_iterations_estimates_loop (struct loop *);
747 void rewrite_into_loop_closed_ssa (bitmap, unsigned);
748 void verify_loop_closed_ssa (void);
749 void loop_commit_inserts (void);
750 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
751 void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
752 		tree *, tree *);
753 void split_loop_exit_edge (edge);
754 void compute_phi_arg_on_exit (edge, tree, tree);
755 unsigned force_expr_to_var_cost (tree);
756 basic_block bsi_insert_on_edge_immediate_loop (edge, tree);
757 void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
758 				     bool *);
759 basic_block ip_end_pos (struct loop *);
760 basic_block ip_normal_pos (struct loop *);
761 bool tree_duplicate_loop_to_header_edge (struct loop *, edge, struct loops *,
762 					 unsigned int, sbitmap,
763 					 edge, edge *,
764 					 unsigned int *, int);
765 struct loop *tree_ssa_loop_version (struct loops *, struct loop *, tree,
766 				    basic_block *);
767 tree expand_simple_operations (tree);
768 void substitute_in_loop_info (struct loop *, tree, tree);
769 edge single_dom_exit (struct loop *);
770 bool contains_abnormal_ssa_name_p (tree);
771 
772 /* In tree-ssa-loop-im.c  */
773 /* The possibilities of statement movement.  */
774 
775 enum move_pos
776   {
777     MOVE_IMPOSSIBLE,		/* No movement -- side effect expression.  */
778     MOVE_PRESERVE_EXECUTION,	/* Must not cause the non-executed statement
779 				   become executed -- memory accesses, ... */
780     MOVE_POSSIBLE		/* Unlimited movement.  */
781   };
782 extern enum move_pos movement_possibility (tree);
783 
784 /* In tree-flow-inline.h  */
785 static inline bool is_call_clobbered (tree);
786 static inline void mark_call_clobbered (tree);
787 static inline void set_is_used (tree);
788 static inline bool unmodifiable_var_p (tree);
789 
790 /* In tree-eh.c  */
791 extern void make_eh_edges (tree);
792 extern bool tree_could_trap_p (tree);
793 extern bool tree_could_throw_p (tree);
794 extern bool tree_can_throw_internal (tree);
795 extern bool tree_can_throw_external (tree);
796 extern int lookup_stmt_eh_region (tree);
797 extern void add_stmt_to_eh_region (tree, int);
798 extern bool remove_stmt_from_eh_region (tree);
799 extern bool maybe_clean_or_replace_eh_stmt (tree, tree);
800 
801 /* In tree-ssa-pre.c  */
802 void add_to_value (tree, tree);
803 void debug_value_expressions (tree);
804 void print_value_expressions (FILE *, tree);
805 
806 
807 /* In tree-vn.c  */
808 bool expressions_equal_p (tree, tree);
809 tree get_value_handle (tree);
810 hashval_t vn_compute (tree, hashval_t, tree);
811 tree vn_lookup_or_add (tree, tree);
812 void vn_add (tree, tree, tree);
813 tree vn_lookup (tree, tree);
814 void vn_init (void);
815 void vn_delete (void);
816 
817 /* In tree-ssa-sink.c  */
818 bool is_hidden_global_store (tree);
819 
820 /* In tree-sra.c  */
821 void insert_edge_copies (tree, basic_block);
822 void sra_insert_before (block_stmt_iterator *, tree);
823 void sra_insert_after (block_stmt_iterator *, tree);
824 void sra_init_cache (void);
825 bool sra_type_can_be_decomposed_p (tree);
826 
827 /* In tree-loop-linear.c  */
828 extern void linear_transform_loops (struct loops *);
829 
830 /* In tree-ssa-loop-ivopts.c  */
831 bool expr_invariant_in_loop_p (struct loop *, tree);
832 bool multiplier_allowed_in_address_p (HOST_WIDE_INT);
833 unsigned multiply_by_cost (HOST_WIDE_INT, enum machine_mode);
834 
835 /* In tree-ssa-threadupdate.c.  */
836 extern bool thread_through_all_blocks (bitmap);
837 
838 /* In gimplify.c  */
839 tree force_gimple_operand (tree, tree *, bool, tree);
840 tree force_gimple_operand_bsi (block_stmt_iterator *, tree, bool, tree);
841 
842 /* In tree-ssa-structalias.c */
843 bool find_what_p_points_to (tree);
844 
845 /* In tree-ssa-address.c  */
846 
847 /* Affine combination of trees.  We keep track of at most MAX_AFF_ELTS elements
848    to make things simpler; this is sufficient in most cases.  */
849 
850 #define MAX_AFF_ELTS 8
851 
852 struct affine_tree_combination
853 {
854   /* Type of the result of the combination.  */
855   tree type;
856 
857   /* Mask modulo that the operations are performed.  */
858   unsigned HOST_WIDE_INT mask;
859 
860   /* Constant offset.  */
861   unsigned HOST_WIDE_INT offset;
862 
863   /* Number of elements of the combination.  */
864   unsigned n;
865 
866   /* Elements and their coefficients.  */
867   tree elts[MAX_AFF_ELTS];
868   unsigned HOST_WIDE_INT coefs[MAX_AFF_ELTS];
869 
870   /* Remainder of the expression.  */
871   tree rest;
872 };
873 
874 /* Description of a memory address.  */
875 
876 struct mem_address
877 {
878   tree symbol, base, index, step, offset;
879 };
880 
881 tree create_mem_ref (block_stmt_iterator *, tree,
882 		     struct affine_tree_combination *);
883 rtx addr_for_mem_ref (struct mem_address *, bool);
884 void get_address_description (tree, struct mem_address *);
885 tree maybe_fold_tmr (tree);
886 /* This structure is simply used during pushing fields onto the fieldstack
887    to track the offset of the field, since bitpos_of_field gives it relative
888    to its immediate containing type, and we want it relative to the ultimate
889    containing object.  */
890 
891 struct fieldoff
892 {
893   tree field;
894   HOST_WIDE_INT offset;
895 };
896 typedef struct fieldoff fieldoff_s;
897 
898 DEF_VEC_O(fieldoff_s);
899 DEF_VEC_ALLOC_O(fieldoff_s,heap);
900 int push_fields_onto_fieldstack (tree, VEC(fieldoff_s,heap) **,
901 				 HOST_WIDE_INT, bool *);
902 void sort_fieldstack (VEC(fieldoff_s,heap) *);
903 
904 void init_alias_heapvars (void);
905 void delete_alias_heapvars (void);
906 
907 #include "tree-flow-inline.h"
908 
909 #endif /* _TREE_FLOW_H  */
910