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
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify
8it under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 2, or (at your option)
10any later version.
11
12GCC is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15GNU General Public License for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING.  If not, write to
19the Free Software Foundation, 51 Franklin Street, Fifth Floor,
20Boston, 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
36struct edge_def;
37typedef struct edge_def *edge;
38struct basic_block_def;
39typedef struct basic_block_def *basic_block;
40#endif
41
42/* True if the code is in ssa form.  */
43extern bool in_ssa_p;
44
45typedef 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.  */
69struct 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  /* Mask of reasons this pointer's value escapes the function  */
97  unsigned int escape_mask;
98};
99
100
101/*---------------------------------------------------------------------------
102		   Tree annotations stored in tree_common.ann
103---------------------------------------------------------------------------*/
104enum tree_ann_type { TREE_ANN_COMMON, VAR_ANN, FUNCTION_ANN, STMT_ANN };
105
106struct tree_ann_common_d GTY(())
107{
108  /* Annotation type.  */
109  enum tree_ann_type type;
110
111 /* Auxiliary info specific to a pass.  At all times, this
112    should either point to valid data or be NULL.  */
113  PTR GTY ((skip (""))) aux;
114
115  /* The value handle for this expression.  Used by GVN-PRE.  */
116  tree GTY((skip)) value_handle;
117};
118
119/* It is advantageous to avoid things like life analysis for variables which
120   do not need PHI nodes.  This enum describes whether or not a particular
121   variable may need a PHI node.  */
122
123enum need_phi_state {
124  /* This is the default.  If we are still in this state after finding
125     all the definition and use sites, then we will assume the variable
126     needs PHI nodes.  This is probably an overly conservative assumption.  */
127  NEED_PHI_STATE_UNKNOWN,
128
129  /* This state indicates that we have seen one or more sets of the
130     variable in a single basic block and that the sets dominate all
131     uses seen so far.  If after finding all definition and use sites
132     we are still in this state, then the variable does not need any
133     PHI nodes.  */
134  NEED_PHI_STATE_NO,
135
136  /* This state indicates that we have either seen multiple definitions of
137     the variable in multiple blocks, or that we encountered a use in a
138     block that was not dominated by the block containing the set(s) of
139     this variable.  This variable is assumed to need PHI nodes.  */
140  NEED_PHI_STATE_MAYBE
141};
142
143struct subvar;
144typedef struct subvar *subvar_t;
145
146/* This structure represents a fake sub-variable for a structure field.  */
147struct subvar GTY(())
148{
149  /* Fake variable.  */
150  tree var;
151
152  /* Next subvar for this structure.  */
153  subvar_t next;
154};
155
156struct var_ann_d GTY(())
157{
158  struct tree_ann_common_d common;
159
160  /* Used by the out of SSA pass to determine whether this variable has
161     been seen yet or not.  */
162  unsigned out_of_ssa_tag : 1;
163
164  /* Used when building root_var structures in tree_ssa_live.[ch].  */
165  unsigned root_var_processed : 1;
166
167  /* Nonzero if this variable is in the alias set of another variable.  */
168  unsigned is_aliased : 1;
169
170  /* Nonzero if this variable was used after SSA optimizations were
171     applied.  We set this when translating out of SSA form.  */
172  unsigned used : 1;
173
174  /* This field indicates whether or not the variable may need PHI nodes.
175     See the enum's definition for more detailed information about the
176     states.  */
177  ENUM_BITFIELD (need_phi_state) need_phi_state : 2;
178
179  /* Used during operand processing to determine if this variable is already
180     in the vuse list.  */
181  unsigned in_vuse_list : 1;
182
183  /* Used during operand processing to determine if this variable is already
184     in the v_may_def list.  */
185  unsigned in_v_may_def_list : 1;
186
187  /* An artificial variable representing the memory location pointed-to by
188     all the pointer symbols that flow-insensitive alias analysis
189     (mostly type-based) considers to be aliased.  If the variable is
190     not a pointer or if it is never dereferenced, this must be NULL.  */
191  tree symbol_mem_tag;
192
193  /* Variables that may alias this variable.  */
194  VEC(tree, gc) *may_aliases;
195
196  /* Used when going out of SSA form to indicate which partition this
197     variable represents storage for.  */
198  unsigned partition;
199
200  /* Used by the root-var object in tree-ssa-live.[ch].  */
201  unsigned root_index;
202
203  /* During into-ssa and the dominator optimizer, this field holds the
204     current version of this variable (an SSA_NAME).  */
205  tree current_def;
206
207  /* If this variable is a structure, this fields holds a list of
208     symbols representing each of the fields of the structure.  */
209  subvar_t subvars;
210
211  /* Mask of values saying the reasons why this variable has escaped
212     the function.  */
213  unsigned int escape_mask;
214};
215
216struct function_ann_d GTY(())
217{
218  struct tree_ann_common_d common;
219
220  /* Pointer to the structure that contains the sets of global
221     variables modified by function calls.  This field is only used
222     for FUNCTION_DECLs.  */
223  ipa_reference_vars_info_t GTY ((skip)) reference_vars_info;
224};
225
226typedef struct immediate_use_iterator_d
227{
228  /* This is the current use the iterator is processing.  */
229  ssa_use_operand_t *imm_use;
230  /* This marks the last use in the list (use node from SSA_NAME)  */
231  ssa_use_operand_t *end_p;
232  /* This node is inserted and used to mark the end of the uses for a stmt.  */
233  ssa_use_operand_t iter_node;
234  /* This is the next ssa_name to visit.  IMM_USE may get removed before
235     the next one is traversed to, so it must be cached early.  */
236  ssa_use_operand_t *next_imm_name;
237} imm_use_iterator;
238
239
240/* Use this iterator when simply looking at stmts.  Adding, deleting or
241   modifying stmts will cause this iterator to malfunction.  */
242
243#define FOR_EACH_IMM_USE_FAST(DEST, ITER, SSAVAR)			\
244  for ((DEST) = first_readonly_imm_use (&(ITER), (SSAVAR));	\
245       !end_readonly_imm_use_p (&(ITER));			\
246       (DEST) = next_readonly_imm_use (&(ITER)))
247
248/* Use this iterator to visit each stmt which has a use of SSAVAR.  */
249
250#define FOR_EACH_IMM_USE_STMT(STMT, ITER, SSAVAR)		\
251  for ((STMT) = first_imm_use_stmt (&(ITER), (SSAVAR));		\
252       !end_imm_use_stmt_p (&(ITER));				\
253       (STMT) = next_imm_use_stmt (&(ITER)))
254
255/* Use this to terminate the FOR_EACH_IMM_USE_STMT loop early.  Failure to
256   do so will result in leaving a iterator marker node in the immediate
257   use list, and nothing good will come from that.   */
258#define BREAK_FROM_IMM_USE_STMT(ITER)				\
259   {								\
260     end_imm_use_stmt_traverse (&(ITER));			\
261     break;							\
262   }
263
264
265/* Use this iterator in combination with FOR_EACH_IMM_USE_STMT to
266   get access to each occurrence of ssavar on the stmt returned by
267   that iterator..  for instance:
268
269     FOR_EACH_IMM_USE_STMT (stmt, iter, var)
270       {
271         FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
272	   {
273	     SET_USE (use_p) = blah;
274	   }
275	 update_stmt (stmt);
276       }							 */
277
278#define FOR_EACH_IMM_USE_ON_STMT(DEST, ITER)			\
279  for ((DEST) = first_imm_use_on_stmt (&(ITER));		\
280       !end_imm_use_on_stmt_p (&(ITER));			\
281       (DEST) = next_imm_use_on_stmt (&(ITER)))
282
283
284
285struct stmt_ann_d GTY(())
286{
287  struct tree_ann_common_d common;
288
289  /* Nonzero if the statement has been modified (meaning that the operands
290     need to be scanned again).  */
291  unsigned modified : 1;
292
293  /* Nonzero if the statement makes references to volatile storage.  */
294  unsigned has_volatile_ops : 1;
295
296  /* Nonzero if the statement makes a function call that may clobber global
297     and local addressable variables.  */
298  unsigned makes_clobbering_call : 1;
299
300  /* Basic block that contains this statement.  */
301  basic_block bb;
302
303  /* Operand cache for stmt.  */
304  struct stmt_operands_d GTY ((skip (""))) operands;
305
306  /* Set of variables that have had their address taken in the statement.  */
307  bitmap addresses_taken;
308
309  /* Unique identifier for this statement.  These ID's are to be created
310     by each pass on an as-needed basis in any order convenient for the
311     pass which needs statement UIDs.  */
312  unsigned int uid;
313
314  /* Linked list of histograms for value-based profiling.  This is really a
315     struct histogram_value*.  We use void* to avoid having to export that
316     everywhere, and to avoid having to put it in GC memory.  */
317
318  void * GTY ((skip (""))) histograms;
319};
320
321union tree_ann_d GTY((desc ("ann_type ((tree_ann_t)&%h)")))
322{
323  struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
324  struct var_ann_d GTY((tag ("VAR_ANN"))) vdecl;
325  struct function_ann_d GTY((tag ("FUNCTION_ANN"))) fdecl;
326  struct stmt_ann_d GTY((tag ("STMT_ANN"))) stmt;
327};
328
329extern GTY(()) VEC(tree,gc) *modified_noreturn_calls;
330
331typedef union tree_ann_d *tree_ann_t;
332typedef struct var_ann_d *var_ann_t;
333typedef struct function_ann_d *function_ann_t;
334typedef struct stmt_ann_d *stmt_ann_t;
335typedef struct tree_ann_common_d *tree_ann_common_t;
336
337static inline tree_ann_common_t tree_common_ann (tree);
338static inline tree_ann_common_t get_tree_common_ann (tree);
339static inline var_ann_t var_ann (tree);
340static inline var_ann_t get_var_ann (tree);
341static inline function_ann_t function_ann (tree);
342static inline function_ann_t get_function_ann (tree);
343static inline stmt_ann_t stmt_ann (tree);
344static inline stmt_ann_t get_stmt_ann (tree);
345static inline enum tree_ann_type ann_type (tree_ann_t);
346static inline basic_block bb_for_stmt (tree);
347extern void set_bb_for_stmt (tree, basic_block);
348static inline bool noreturn_call_p (tree);
349static inline void update_stmt (tree);
350static inline bool stmt_modified_p (tree);
351static inline VEC(tree, gc) *may_aliases (tree);
352static inline int get_lineno (tree);
353static inline const char *get_filename (tree);
354static inline bool is_exec_stmt (tree);
355static inline bool is_label_stmt (tree);
356static inline bitmap addresses_taken (tree);
357
358/*---------------------------------------------------------------------------
359                  Structure representing predictions in tree level.
360---------------------------------------------------------------------------*/
361struct edge_prediction GTY((chain_next ("%h.ep_next")))
362{
363  struct edge_prediction *ep_next;
364  edge ep_edge;
365  enum br_predictor ep_predictor;
366  int ep_probability;
367};
368
369/* Accessors for basic block annotations.  */
370static inline tree phi_nodes (basic_block);
371static inline void set_phi_nodes (basic_block, tree);
372
373/*---------------------------------------------------------------------------
374			      Global declarations
375---------------------------------------------------------------------------*/
376struct int_tree_map GTY(())
377{
378
379  unsigned int uid;
380  tree to;
381};
382
383extern unsigned int int_tree_map_hash (const void *);
384extern int int_tree_map_eq (const void *, const void *);
385
386typedef 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
403typedef 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.  */
422extern GTY((param_is (struct int_tree_map))) htab_t referenced_vars;
423
424/* Default defs for undefined symbols. */
425extern GTY((param_is (struct int_tree_map))) htab_t default_defs;
426
427extern tree referenced_var_lookup (unsigned int);
428extern bool referenced_var_check_and_insert (tree);
429#define num_referenced_vars htab_elements (referenced_vars)
430#define referenced_var(i) referenced_var_lookup (i)
431
432/* Array of all SSA_NAMEs used in the function.  */
433extern GTY(()) VEC(tree,gc) *ssa_names;
434
435#define num_ssa_names (VEC_length (tree, ssa_names))
436#define ssa_name(i) (VEC_index (tree, ssa_names, (i)))
437
438/* Artificial variable used to model the effects of function calls.  */
439extern GTY(()) tree global_var;
440
441/* Artificial variable used to model the effects of nonlocal
442   variables.  */
443extern GTY(()) tree nonlocal_all;
444
445/* Call clobbered variables in the function.  If bit I is set, then
446   REFERENCED_VARS (I) is call-clobbered.  */
447extern bitmap call_clobbered_vars;
448
449/* Addressable variables in the function.  If bit I is set, then
450   REFERENCED_VARS (I) has had its address taken.  */
451extern bitmap addressable_vars;
452
453/* 'true' after aliases have been computed (see compute_may_aliases).  */
454extern bool aliases_computed_p;
455
456/* Macros for showing usage statistics.  */
457#define SCALE(x) ((unsigned long) ((x) < 1024*10	\
458		  ? (x)					\
459		  : ((x) < 1024*1024*10			\
460		     ? (x) / 1024			\
461		     : (x) / (1024*1024))))
462
463#define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
464
465#define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
466
467/*---------------------------------------------------------------------------
468			      Block iterators
469---------------------------------------------------------------------------*/
470
471typedef struct {
472  tree_stmt_iterator tsi;
473  basic_block bb;
474} block_stmt_iterator;
475
476static inline block_stmt_iterator bsi_start (basic_block);
477static inline block_stmt_iterator bsi_last (basic_block);
478static inline block_stmt_iterator bsi_after_labels (basic_block);
479block_stmt_iterator bsi_for_stmt (tree);
480static inline bool bsi_end_p (block_stmt_iterator);
481static inline void bsi_next (block_stmt_iterator *);
482static inline void bsi_prev (block_stmt_iterator *);
483static inline tree bsi_stmt (block_stmt_iterator);
484static inline tree * bsi_stmt_ptr (block_stmt_iterator);
485
486extern void bsi_remove (block_stmt_iterator *, bool);
487extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
488extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
489extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
490
491enum bsi_iterator_update
492{
493  /* Note that these are intentionally in the same order as TSI_FOO.  They
494     mean exactly the same as their TSI_* counterparts.  */
495  BSI_NEW_STMT,
496  BSI_SAME_STMT,
497  BSI_CHAIN_START,
498  BSI_CHAIN_END,
499  BSI_CONTINUE_LINKING
500};
501
502extern void bsi_insert_before (block_stmt_iterator *, tree,
503			       enum bsi_iterator_update);
504extern void bsi_insert_after (block_stmt_iterator *, tree,
505			      enum bsi_iterator_update);
506
507extern void bsi_replace (const block_stmt_iterator *, tree, bool);
508
509/*---------------------------------------------------------------------------
510			      OpenMP Region Tree
511---------------------------------------------------------------------------*/
512
513/* Parallel region information.  Every parallel and workshare
514   directive is enclosed between two markers, the OMP_* directive
515   and a corresponding OMP_RETURN statement.  */
516
517struct omp_region
518{
519  /* The enclosing region.  */
520  struct omp_region *outer;
521
522  /* First child region.  */
523  struct omp_region *inner;
524
525  /* Next peer region.  */
526  struct omp_region *next;
527
528  /* Block containing the omp directive as its last stmt.  */
529  basic_block entry;
530
531  /* Block containing the OMP_RETURN as its last stmt.  */
532  basic_block exit;
533
534  /* Block containing the OMP_CONTINUE as its last stmt.  */
535  basic_block cont;
536
537  /* If this is a combined parallel+workshare region, this is a list
538     of additional arguments needed by the combined parallel+workshare
539     library call.  */
540  tree ws_args;
541
542  /* The code for the omp directive of this region.  */
543  enum tree_code type;
544
545  /* Schedule kind, only used for OMP_FOR type regions.  */
546  enum omp_clause_schedule_kind sched_kind;
547
548  /* True if this is a combined parallel+workshare region.  */
549  bool is_combined_parallel;
550};
551
552extern struct omp_region *root_omp_region;
553extern struct omp_region *new_omp_region (basic_block, enum tree_code,
554					  struct omp_region *);
555extern void free_omp_regions (void);
556
557/*---------------------------------------------------------------------------
558			      Function prototypes
559---------------------------------------------------------------------------*/
560/* In tree-cfg.c  */
561
562/* Location to track pending stmt for edge insertion.  */
563#define PENDING_STMT(e)	((e)->insns.t)
564
565extern void delete_tree_cfg_annotations (void);
566extern void disband_implicit_edges (void);
567extern bool stmt_ends_bb_p (tree);
568extern bool is_ctrl_stmt (tree);
569extern bool is_ctrl_altering_stmt (tree);
570extern bool computed_goto_p (tree);
571extern bool simple_goto_p (tree);
572extern bool tree_can_make_abnormal_goto (tree);
573extern basic_block single_noncomplex_succ (basic_block bb);
574extern void tree_dump_bb (basic_block, FILE *, int);
575extern void debug_tree_bb (basic_block);
576extern basic_block debug_tree_bb_n (int);
577extern void dump_tree_cfg (FILE *, int);
578extern void debug_tree_cfg (int);
579extern void dump_cfg_stats (FILE *);
580extern void debug_cfg_stats (void);
581extern void debug_loop_ir (void);
582extern void print_loop_ir (FILE *);
583extern void cleanup_dead_labels (void);
584extern void group_case_labels (void);
585extern tree first_stmt (basic_block);
586extern tree last_stmt (basic_block);
587extern tree *last_stmt_ptr (basic_block);
588extern tree last_and_only_stmt (basic_block);
589extern edge find_taken_edge (basic_block, tree);
590extern basic_block label_to_block_fn (struct function *, tree);
591#define label_to_block(t) (label_to_block_fn (cfun, t))
592extern void bsi_insert_on_edge (edge, tree);
593extern basic_block bsi_insert_on_edge_immediate (edge, tree);
594extern void bsi_commit_one_edge_insert (edge, basic_block *);
595extern void bsi_commit_edge_inserts (void);
596extern void notice_special_calls (tree);
597extern void clear_special_calls (void);
598extern void verify_stmts (void);
599extern tree tree_block_label (basic_block);
600extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
601extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
602					basic_block *);
603extern void add_phi_args_after_copy_bb (basic_block);
604extern void add_phi_args_after_copy (basic_block *, unsigned);
605extern bool tree_purge_dead_abnormal_call_edges (basic_block);
606extern bool tree_purge_dead_eh_edges (basic_block);
607extern bool tree_purge_all_dead_eh_edges (bitmap);
608extern tree gimplify_val (block_stmt_iterator *, tree, tree);
609extern tree gimplify_build1 (block_stmt_iterator *, enum tree_code,
610			     tree, tree);
611extern tree gimplify_build2 (block_stmt_iterator *, enum tree_code,
612			     tree, tree, tree);
613extern tree gimplify_build3 (block_stmt_iterator *, enum tree_code,
614			     tree, tree, tree, tree);
615extern void init_empty_tree_cfg (void);
616extern void fold_cond_expr_cond (void);
617extern void make_abnormal_goto_edges (basic_block, bool);
618extern void replace_uses_by (tree, tree);
619extern void start_recording_case_labels (void);
620extern void end_recording_case_labels (void);
621extern basic_block move_sese_region_to_fn (struct function *, basic_block,
622				           basic_block);
623
624/* In tree-cfgcleanup.c  */
625extern bool cleanup_tree_cfg (void);
626extern void cleanup_tree_cfg_loop (void);
627
628/* In tree-pretty-print.c.  */
629extern void dump_generic_bb (FILE *, basic_block, int, int);
630
631/* In tree-dfa.c  */
632extern var_ann_t create_var_ann (tree);
633extern function_ann_t create_function_ann (tree);
634extern stmt_ann_t create_stmt_ann (tree);
635extern tree_ann_common_t create_tree_common_ann (tree);
636extern void dump_dfa_stats (FILE *);
637extern void debug_dfa_stats (void);
638extern void debug_referenced_vars (void);
639extern void dump_referenced_vars (FILE *);
640extern void dump_variable (FILE *, tree);
641extern void debug_variable (tree);
642extern void dump_subvars_for (FILE *, tree);
643extern void debug_subvars_for (tree);
644extern tree get_virtual_var (tree);
645extern void add_referenced_var (tree);
646extern void mark_new_vars_to_rename (tree);
647extern void find_new_referenced_vars (tree *);
648
649extern tree make_rename_temp (tree, const char *);
650extern void set_default_def (tree, tree);
651extern tree default_def (tree);
652extern tree default_def_fn (struct function *, tree);
653
654/* In tree-phinodes.c  */
655extern void reserve_phi_args_for_new_edge (basic_block);
656extern tree create_phi_node (tree, basic_block);
657extern void add_phi_arg (tree, tree, edge);
658extern void remove_phi_args (edge);
659extern void remove_phi_node (tree, tree);
660extern tree phi_reverse (tree);
661
662/* In gimple-low.c  */
663extern void record_vars_into (tree, tree);
664extern void record_vars (tree);
665extern bool block_may_fallthru (tree);
666
667/* In tree-ssa-alias.c  */
668extern void dump_may_aliases_for (FILE *, tree);
669extern void debug_may_aliases_for (tree);
670extern void dump_alias_info (FILE *);
671extern void debug_alias_info (void);
672extern void dump_points_to_info (FILE *);
673extern void debug_points_to_info (void);
674extern void dump_points_to_info_for (FILE *, tree);
675extern void debug_points_to_info_for (tree);
676extern bool may_be_aliased (tree);
677extern bool is_aliased_with (tree, tree);
678extern bool may_aliases_intersect (tree, tree);
679extern struct ptr_info_def *get_ptr_info (tree);
680extern void new_type_alias (tree, tree, tree);
681extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *, bool *);
682static inline subvar_t get_subvars_for_var (tree);
683static inline tree get_subvar_at (tree, unsigned HOST_WIDE_INT);
684static inline bool ref_contains_array_ref (tree);
685static inline bool array_ref_contains_indirect_ref (tree);
686extern tree get_ref_base_and_extent (tree, HOST_WIDE_INT *,
687				     HOST_WIDE_INT *, HOST_WIDE_INT *);
688static inline bool var_can_have_subvars (tree);
689static inline bool overlap_subvar (unsigned HOST_WIDE_INT,
690				   unsigned HOST_WIDE_INT,
691				   tree, bool *);
692
693/* Call-back function for walk_use_def_chains().  At each reaching
694   definition, a function with this prototype is called.  */
695typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
696
697/* In tree-ssa-alias-warnings.c  */
698extern void strict_aliasing_warning_backend (void);
699
700/* In tree-ssa.c  */
701extern void init_tree_ssa (void);
702extern edge ssa_redirect_edge (edge, basic_block);
703extern void flush_pending_stmts (edge);
704extern bool tree_ssa_useless_type_conversion (tree);
705extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
706extern void verify_ssa (bool);
707extern void delete_tree_ssa (void);
708extern void register_new_def (tree, VEC(tree,heap) **);
709extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *, bool);
710extern bool stmt_references_memory_p (tree);
711
712/* In tree-into-ssa.c  */
713void update_ssa (unsigned);
714void delete_update_ssa (void);
715void register_new_name_mapping (tree, tree);
716tree create_new_def_for (tree, tree, def_operand_p);
717bool need_ssa_update_p (void);
718bool name_registered_for_update_p (tree);
719bitmap ssa_names_to_replace (void);
720void release_ssa_name_after_update_ssa (tree name);
721void compute_global_livein (bitmap, bitmap);
722tree duplicate_ssa_name (tree, tree);
723void mark_sym_for_renaming (tree);
724void mark_set_for_renaming (bitmap);
725tree get_current_def (tree);
726void set_current_def (tree, tree);
727
728/* In tree-ssa-ccp.c  */
729bool fold_stmt (tree *);
730bool fold_stmt_inplace (tree);
731tree widen_bitfield (tree, tree, tree);
732
733/* In tree-vrp.c  */
734tree vrp_evaluate_conditional (tree, tree);
735void simplify_stmt_using_ranges (tree);
736
737/* In tree-ssa-dom.c  */
738extern void dump_dominator_optimization_stats (FILE *);
739extern void debug_dominator_optimization_stats (void);
740int loop_depth_of_name (tree);
741
742/* In tree-ssa-copy.c  */
743extern void merge_alias_info (tree, tree);
744extern void propagate_value (use_operand_p, tree);
745extern void propagate_tree_value (tree *, tree);
746extern void replace_exp (use_operand_p, tree);
747extern bool may_propagate_copy (tree, tree);
748extern bool may_propagate_copy_into_asm (tree);
749
750/* Affine iv.  */
751
752typedef struct
753{
754  /* Iv = BASE + STEP * i.  */
755  tree base, step;
756
757  /* True if this iv does not overflow.  */
758  bool no_overflow;
759} affine_iv;
760
761/* Description of number of iterations of a loop.  All the expressions inside
762   the structure can be evaluated at the end of the loop's preheader
763   (and due to ssa form, also anywhere inside the body of the loop).  */
764
765struct tree_niter_desc
766{
767  tree assumptions;	/* The boolean expression.  If this expression evaluates
768			   to false, then the other fields in this structure
769			   should not be used; there is no guarantee that they
770			   will be correct.  */
771  tree may_be_zero;	/* The boolean expression.  If it evaluates to true,
772			   the loop will exit in the first iteration (i.e.
773			   its latch will not be executed), even if the niter
774			   field says otherwise.  */
775  tree niter;		/* The expression giving the number of iterations of
776			   a loop (provided that assumptions == true and
777			   may_be_zero == false), more precisely the number
778			   of executions of the latch of the loop.  */
779  tree additional_info;	/* The boolean expression.  Sometimes we use additional
780			   knowledge to simplify the other expressions
781			   contained in this structure (for example the
782			   knowledge about value ranges of operands on entry to
783			   the loop).  If this is a case, conjunction of such
784			   condition is stored in this field, so that we do not
785			   lose the information: for example if may_be_zero
786			   is (n <= 0) and niter is (unsigned) n, we know
787			   that the number of iterations is at most
788			   MAX_SIGNED_INT.  However if the (n <= 0) assumption
789			   is eliminated (by looking at the guard on entry of
790			   the loop), then the information would be lost.  */
791
792  /* The simplified shape of the exit condition.  The loop exits if
793     CONTROL CMP BOUND is false, where CMP is one of NE_EXPR,
794     LT_EXPR, or GT_EXPR, and step of CONTROL is positive if CMP is
795     LE_EXPR and negative if CMP is GE_EXPR.  This information is used
796     by loop unrolling.  */
797  affine_iv control;
798  tree bound;
799  enum tree_code cmp;
800};
801
802/* In tree-vectorizer.c */
803void vectorize_loops (struct loops *);
804extern bool vect_can_force_dr_alignment_p (tree, unsigned int);
805extern tree get_vectype_for_scalar_type (tree);
806
807/* In tree-ssa-phiopt.c */
808bool empty_block_p (basic_block);
809
810/* In tree-ssa-loop*.c  */
811
812void tree_ssa_lim (struct loops *);
813unsigned int tree_ssa_unswitch_loops (struct loops *);
814unsigned int canonicalize_induction_variables (struct loops *);
815unsigned int tree_unroll_loops_completely (struct loops *, bool);
816unsigned int tree_ssa_prefetch_arrays (struct loops *);
817unsigned int remove_empty_loops (struct loops *);
818void tree_ssa_iv_optimize (struct loops *);
819
820bool number_of_iterations_exit (struct loop *, edge,
821				struct tree_niter_desc *niter, bool);
822tree find_loop_niter (struct loop *, edge *);
823tree loop_niter_by_eval (struct loop *, edge);
824tree find_loop_niter_by_eval (struct loop *, edge *);
825void estimate_numbers_of_iterations (struct loops *);
826bool scev_probably_wraps_p (tree, tree, tree, struct loop *, bool);
827bool convert_affine_scev (struct loop *, tree, tree *, tree *, tree, bool);
828
829bool nowrap_type_p (tree);
830enum ev_direction {EV_DIR_GROWS, EV_DIR_DECREASES, EV_DIR_UNKNOWN};
831enum ev_direction scev_direction (tree);
832
833void free_numbers_of_iterations_estimates (struct loops *);
834void free_numbers_of_iterations_estimates_loop (struct loop *);
835void rewrite_into_loop_closed_ssa (bitmap, unsigned);
836void verify_loop_closed_ssa (void);
837void loop_commit_inserts (void);
838bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
839void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
840		tree *, tree *);
841void split_loop_exit_edge (edge);
842unsigned force_expr_to_var_cost (tree);
843basic_block bsi_insert_on_edge_immediate_loop (edge, tree);
844void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
845				     bool *);
846basic_block ip_end_pos (struct loop *);
847basic_block ip_normal_pos (struct loop *);
848bool tree_duplicate_loop_to_header_edge (struct loop *, edge, struct loops *,
849					 unsigned int, sbitmap,
850					 edge, edge *,
851					 unsigned int *, int);
852struct loop *tree_ssa_loop_version (struct loops *, struct loop *, tree,
853				    basic_block *);
854tree expand_simple_operations (tree);
855void substitute_in_loop_info (struct loop *, tree, tree);
856edge single_dom_exit (struct loop *);
857bool can_unroll_loop_p (struct loop *loop, unsigned factor,
858			struct tree_niter_desc *niter);
859void tree_unroll_loop (struct loops *, struct loop *, unsigned,
860		       edge, struct tree_niter_desc *);
861bool contains_abnormal_ssa_name_p (tree);
862
863/* In tree-ssa-threadedge.c */
864extern bool potentially_threadable_block (basic_block);
865extern void thread_across_edge (tree, edge, bool,
866				VEC(tree, heap) **, tree (*) (tree, tree));
867
868/* In tree-ssa-loop-im.c  */
869/* The possibilities of statement movement.  */
870
871enum move_pos
872  {
873    MOVE_IMPOSSIBLE,		/* No movement -- side effect expression.  */
874    MOVE_PRESERVE_EXECUTION,	/* Must not cause the non-executed statement
875				   become executed -- memory accesses, ... */
876    MOVE_POSSIBLE		/* Unlimited movement.  */
877  };
878extern enum move_pos movement_possibility (tree);
879
880/* The reasons a variable may escape a function.  */
881enum escape_type
882  {
883    NO_ESCAPE = 0, /* Doesn't escape.  */
884    ESCAPE_STORED_IN_GLOBAL = 1 << 1,
885    ESCAPE_TO_ASM = 1 << 2,  /* Passed by address to an assembly
886				statement.  */
887    ESCAPE_TO_CALL = 1 << 3,  /* Escapes to a function call.  */
888    ESCAPE_BAD_CAST = 1 << 4, /* Cast from pointer to integer */
889    ESCAPE_TO_RETURN = 1 << 5, /* Returned from function.  */
890    ESCAPE_TO_PURE_CONST = 1 << 6, /* Escapes to a pure or constant
891				      function call.  */
892    ESCAPE_IS_GLOBAL = 1 << 7,  /* Is a global variable.  */
893    ESCAPE_IS_PARM = 1 << 8, /* Is an incoming function parameter.  */
894    ESCAPE_UNKNOWN = 1 << 9 /* We believe it escapes for some reason
895			       not enumerated above.  */
896  };
897
898/* In tree-flow-inline.h  */
899static inline bool is_call_clobbered (tree);
900static inline void mark_call_clobbered (tree, unsigned int);
901static inline void set_is_used (tree);
902static inline bool unmodifiable_var_p (tree);
903
904/* In tree-eh.c  */
905extern void make_eh_edges (tree);
906extern bool tree_could_trap_p (tree);
907extern bool tree_could_throw_p (tree);
908extern bool tree_can_throw_internal (tree);
909extern bool tree_can_throw_external (tree);
910extern int lookup_stmt_eh_region (tree);
911extern void add_stmt_to_eh_region (tree, int);
912extern bool remove_stmt_from_eh_region (tree);
913extern bool maybe_clean_or_replace_eh_stmt (tree, tree);
914
915/* In tree-ssa-pre.c  */
916void add_to_value (tree, tree);
917void debug_value_expressions (tree);
918void print_value_expressions (FILE *, tree);
919
920
921/* In tree-vn.c  */
922bool expressions_equal_p (tree, tree);
923tree get_value_handle (tree);
924hashval_t vn_compute (tree, hashval_t);
925void sort_vuses (VEC (tree, gc) *);
926tree vn_lookup_or_add (tree, tree);
927tree vn_lookup_or_add_with_vuses (tree, VEC (tree, gc) *);
928void vn_add (tree, tree);
929void vn_add_with_vuses (tree, tree, VEC (tree, gc) *);
930tree vn_lookup (tree, tree);
931tree vn_lookup_with_vuses (tree, VEC (tree, gc) *);
932void vn_init (void);
933void vn_delete (void);
934
935/* In tree-ssa-sink.c  */
936bool is_hidden_global_store (tree);
937
938/* In tree-sra.c  */
939void insert_edge_copies (tree, basic_block);
940void sra_insert_before (block_stmt_iterator *, tree);
941void sra_insert_after (block_stmt_iterator *, tree);
942void sra_init_cache (void);
943bool sra_type_can_be_decomposed_p (tree);
944
945/* In tree-loop-linear.c  */
946extern void linear_transform_loops (struct loops *);
947
948/* In tree-ssa-loop-ivopts.c  */
949bool expr_invariant_in_loop_p (struct loop *, tree);
950bool multiplier_allowed_in_address_p (HOST_WIDE_INT);
951unsigned multiply_by_cost (HOST_WIDE_INT, enum machine_mode);
952
953/* In tree-ssa-threadupdate.c.  */
954extern bool thread_through_all_blocks (void);
955extern void register_jump_thread (edge, edge);
956
957/* In gimplify.c  */
958tree force_gimple_operand (tree, tree *, bool, tree);
959tree force_gimple_operand_bsi (block_stmt_iterator *, tree, bool, tree);
960
961/* In tree-ssa-structalias.c */
962bool find_what_p_points_to (tree);
963
964/* In tree-ssa-live.c */
965extern void remove_unused_locals (void);
966
967/* In tree-ssa-address.c  */
968
969/* Affine combination of trees.  We keep track of at most MAX_AFF_ELTS elements
970   to make things simpler; this is sufficient in most cases.  */
971
972#define MAX_AFF_ELTS 8
973
974struct affine_tree_combination
975{
976  /* Type of the result of the combination.  */
977  tree type;
978
979  /* Mask modulo that the operations are performed.  */
980  unsigned HOST_WIDE_INT mask;
981
982  /* Constant offset.  */
983  unsigned HOST_WIDE_INT offset;
984
985  /* Number of elements of the combination.  */
986  unsigned n;
987
988  /* Elements and their coefficients.  */
989  tree elts[MAX_AFF_ELTS];
990  unsigned HOST_WIDE_INT coefs[MAX_AFF_ELTS];
991
992  /* Remainder of the expression.  */
993  tree rest;
994};
995
996/* Description of a memory address.  */
997
998struct mem_address
999{
1000  tree symbol, base, index, step, offset;
1001};
1002
1003tree create_mem_ref (block_stmt_iterator *, tree,
1004		     struct affine_tree_combination *);
1005rtx addr_for_mem_ref (struct mem_address *, bool);
1006void get_address_description (tree, struct mem_address *);
1007tree maybe_fold_tmr (tree);
1008
1009/* This structure is simply used during pushing fields onto the fieldstack
1010   to track the offset of the field, since bitpos_of_field gives it relative
1011   to its immediate containing type, and we want it relative to the ultimate
1012   containing object.  */
1013
1014struct fieldoff
1015{
1016  tree type;
1017  tree size;
1018  tree decl;
1019  HOST_WIDE_INT offset;
1020};
1021typedef struct fieldoff fieldoff_s;
1022
1023DEF_VEC_O(fieldoff_s);
1024DEF_VEC_ALLOC_O(fieldoff_s,heap);
1025int push_fields_onto_fieldstack (tree, VEC(fieldoff_s,heap) **,
1026				 HOST_WIDE_INT, bool *);
1027void sort_fieldstack (VEC(fieldoff_s,heap) *);
1028
1029void init_alias_heapvars (void);
1030void delete_alias_heapvars (void);
1031
1032#include "tree-flow-inline.h"
1033
1034void swap_tree_operands (tree, tree *, tree *);
1035
1036extern void recalculate_used_alone (void);
1037extern bool updating_used_alone;
1038#endif /* _TREE_FLOW_H  */
1039