gcc/tree-flow.h

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