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 #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   /* 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 ---------------------------------------------------------------------------*/
 104 enum tree_ann_type { TREE_ANN_COMMON, VAR_ANN, FUNCTION_ANN, STMT_ANN };
 105
 106 struct 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
 123 enum 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
 143 struct subvar;
 144 typedef struct subvar *subvar_t;
 145
 146 /* This structure represents a fake sub-variable for a structure field.  */
 147 struct subvar GTY(())
 148 {
 149   /* Fake variable.  */
 150   tree var;
 151
 152   /* Next subvar for this structure.  */
 153   subvar_t next;
 154 };
 155
 156 struct 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
 216 struct 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
 226 typedef struct immediate_use_iterator_d
 227 {
 228   ssa_use_operand_t *imm_use;
 229   ssa_use_operand_t *end_p;
 230   ssa_use_operand_t iter_node;
 231 } imm_use_iterator;
 232
 233
 234 /* Use this iterator when simply looking at stmts.  Adding, deleting or
 235    modifying stmts will cause this iterator to malfunction.  */
 236
 237 #define FOR_EACH_IMM_USE_FAST(DEST, ITER, SSAVAR)                       \
 238   for ((DEST) = first_readonly_imm_use (&(ITER), (SSAVAR));     \
 239        !end_readonly_imm_use_p (&(ITER));                       \
 240        (DEST) = next_readonly_imm_use (&(ITER)))
 241
 242
 243 #define FOR_EACH_IMM_USE_SAFE(DEST, ITER, SSAVAR)               \
 244   for ((DEST) = first_safe_imm_use (&(ITER), (SSAVAR));         \
 245        !end_safe_imm_use_p (&(ITER));                           \
 246        (DEST) = next_safe_imm_use (&(ITER)))
 247
 248 #define BREAK_FROM_SAFE_IMM_USE(ITER)                           \
 249    {                                                            \
 250      end_safe_imm_use_traverse (&(ITER));                       \
 251      break;                                                     \
 252    }
 253
 254 struct stmt_ann_d GTY(())
 255 {
 256   struct tree_ann_common_d common;
 257
 258   /* Nonzero if the statement has been modified (meaning that the operands
 259      need to be scanned again).  */
 260   unsigned modified : 1;
 261
 262   /* Nonzero if the statement makes references to volatile storage.  */
 263   unsigned has_volatile_ops : 1;
 264
 265   /* Nonzero if the statement makes a function call that may clobber global
 266      and local addressable variables.  */
 267   unsigned makes_clobbering_call : 1;
 268
 269   /* Basic block that contains this statement.  */
 270   basic_block bb;
 271
 272   /* Operand cache for stmt.  */
 273   struct stmt_operands_d GTY ((skip (""))) operands;
 274
 275   /* Set of variables that have had their address taken in the statement.  */
 276   bitmap addresses_taken;
 277
 278   /* Unique identifier for this statement.  These ID's are to be created
 279      by each pass on an as-needed basis in any order convenient for the
 280      pass which needs statement UIDs.  */
 281   unsigned int uid;
 282
 283   /* Linked list of histograms for value-based profiling.  This is really a
 284      struct histogram_value*.  We use void* to avoid having to export that
 285      everywhere, and to avoid having to put it in GC memory.  */
 286
 287   void * GTY ((skip (""))) histograms;
 288 };
 289
 290 union tree_ann_d GTY((desc ("ann_type ((tree_ann_t)&%h)")))
 291 {
 292   struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
 293   struct var_ann_d GTY((tag ("VAR_ANN"))) vdecl;
 294   struct function_ann_d GTY((tag ("FUNCTION_ANN"))) fdecl;
 295   struct stmt_ann_d GTY((tag ("STMT_ANN"))) stmt;
 296 };
 297
 298 extern GTY(()) VEC(tree,gc) *modified_noreturn_calls;
 299
 300 typedef union tree_ann_d *tree_ann_t;
 301 typedef struct var_ann_d *var_ann_t;
 302 typedef struct function_ann_d *function_ann_t;
 303 typedef struct stmt_ann_d *stmt_ann_t;
 304
 305 static inline tree_ann_t tree_ann (tree);
 306 static inline tree_ann_t get_tree_ann (tree);
 307 static inline var_ann_t var_ann (tree);
 308 static inline var_ann_t get_var_ann (tree);
 309 static inline function_ann_t function_ann (tree);
 310 static inline function_ann_t get_function_ann (tree);
 311 static inline stmt_ann_t stmt_ann (tree);
 312 static inline stmt_ann_t get_stmt_ann (tree);
 313 static inline enum tree_ann_type ann_type (tree_ann_t);
 314 static inline basic_block bb_for_stmt (tree);
 315 extern void set_bb_for_stmt (tree, basic_block);
 316 static inline bool noreturn_call_p (tree);
 317 static inline void update_stmt (tree);
 318 static inline bool stmt_modified_p (tree);
 319 static inline VEC(tree, gc) *may_aliases (tree);
 320 static inline int get_lineno (tree);
 321 static inline const char *get_filename (tree);
 322 static inline bool is_exec_stmt (tree);
 323 static inline bool is_label_stmt (tree);
 324 static inline bitmap addresses_taken (tree);
 325
 326 /*---------------------------------------------------------------------------
 327                   Structure representing predictions in tree level.
 328 ---------------------------------------------------------------------------*/
 329 struct edge_prediction GTY((chain_next ("%h.ep_next")))
 330 {
 331   struct edge_prediction *ep_next;
 332   edge ep_edge;
 333   enum br_predictor ep_predictor;
 334   int ep_probability;
 335 };
 336
 337 /* Accessors for basic block annotations.  */
 338 static inline tree phi_nodes (basic_block);
 339 static inline void set_phi_nodes (basic_block, tree);
 340
 341 /*---------------------------------------------------------------------------
 342                               Global declarations
 343 ---------------------------------------------------------------------------*/
 344 struct int_tree_map GTY(())
 345 {
 346
 347   unsigned int uid;
 348   tree to;
 349 };
 350
 351 extern unsigned int int_tree_map_hash (const void *);
 352 extern int int_tree_map_eq (const void *, const void *);
 353
 354 typedef struct
 355 {
 356   htab_iterator hti;
 357 } referenced_var_iterator;
 358
 359
 360 /* This macro loops over all the referenced vars, one at a time, putting the
 361    current var in VAR.  Note:  You are not allowed to add referenced variables
 362    to the hashtable while using this macro.  Doing so may cause it to behave
 363    erratically.  */
 364
 365 #define FOR_EACH_REFERENCED_VAR(VAR, ITER) \
 366   for ((VAR) = first_referenced_var (&(ITER)); \
 367        !end_referenced_vars_p (&(ITER)); \
 368        (VAR) = next_referenced_var (&(ITER)))
 369
 370
 371 typedef struct
 372 {
 373   int i;
 374 } safe_referenced_var_iterator;
 375
 376 /* This macro loops over all the referenced vars, one at a time, putting the
 377    current var in VAR.  You are allowed to add referenced variables during the
 378    execution of this macro, however, the macro will not iterate over them.  It
 379    requires a temporary vector of trees, VEC, whose lifetime is controlled by
 380    the caller.  The purpose of the vector is to temporarily store the
 381    referenced_variables hashtable so that adding referenced variables does not
 382    affect the hashtable.  */
 383
 384 #define FOR_EACH_REFERENCED_VAR_SAFE(VAR, VEC, ITER) \
 385   for ((ITER).i = 0, fill_referenced_var_vec (&(VEC)); \
 386        VEC_iterate (tree, (VEC), (ITER).i, (VAR)); \
 387        (ITER).i++)
 388
 389 /* Array of all variables referenced in the function.  */
 390 extern GTY((param_is (struct int_tree_map))) htab_t referenced_vars;
 391
 392 /* Default defs for undefined symbols. */
 393 extern GTY((param_is (struct int_tree_map))) htab_t default_defs;
 394
 395 extern tree referenced_var_lookup (unsigned int);
 396 #define num_referenced_vars htab_elements (referenced_vars)
 397 #define referenced_var(i) referenced_var_lookup (i)
 398
 399 /* Array of all SSA_NAMEs used in the function.  */
 400 extern GTY(()) VEC(tree,gc) *ssa_names;
 401
 402 #define num_ssa_names (VEC_length (tree, ssa_names))
 403 #define ssa_name(i) (VEC_index (tree, ssa_names, (i)))
 404
 405 /* Artificial variable used to model the effects of function calls.  */
 406 extern GTY(()) tree global_var;
 407
 408 /* Call clobbered variables in the function.  If bit I is set, then
 409    REFERENCED_VARS (I) is call-clobbered.  */
 410 extern bitmap call_clobbered_vars;
 411
 412 /* Addressable variables in the function.  If bit I is set, then
 413    REFERENCED_VARS (I) has had its address taken.  */
 414 extern bitmap addressable_vars;
 415
 416 /* 'true' after aliases have been computed (see compute_may_aliases).  */
 417 extern bool aliases_computed_p;
 418
 419 /* Macros for showing usage statistics.  */
 420 #define SCALE(x) ((unsigned long) ((x) < 1024*10        \
 421                   ? (x)                                 \
 422                   : ((x) < 1024*1024*10                 \
 423                      ? (x) / 1024                       \
 424                      : (x) / (1024*1024))))
 425
 426 #define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
 427
 428 #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
 429
 430 /*---------------------------------------------------------------------------
 431                               Block iterators
 432 ---------------------------------------------------------------------------*/
 433
 434 typedef struct {
 435   tree_stmt_iterator tsi;
 436   basic_block bb;
 437 } block_stmt_iterator;
 438
 439 static inline block_stmt_iterator bsi_start (basic_block);
 440 static inline block_stmt_iterator bsi_last (basic_block);
 441 static inline block_stmt_iterator bsi_after_labels (basic_block);
 442 block_stmt_iterator bsi_for_stmt (tree);
 443 static inline bool bsi_end_p (block_stmt_iterator);
 444 static inline void bsi_next (block_stmt_iterator *);
 445 static inline void bsi_prev (block_stmt_iterator *);
 446 static inline tree bsi_stmt (block_stmt_iterator);
 447 static inline tree * bsi_stmt_ptr (block_stmt_iterator);
 448
 449 extern void bsi_remove (block_stmt_iterator *, bool);
 450 extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
 451 extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
 452 extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
 453
 454 enum bsi_iterator_update
 455 {
 456   /* Note that these are intentionally in the same order as TSI_FOO.  They
 457      mean exactly the same as their TSI_* counterparts.  */
 458   BSI_NEW_STMT,
 459   BSI_SAME_STMT,
 460   BSI_CHAIN_START,
 461   BSI_CHAIN_END,
 462   BSI_CONTINUE_LINKING
 463 };
 464
 465 extern void bsi_insert_before (block_stmt_iterator *, tree,
 466                                enum bsi_iterator_update);
 467 extern void bsi_insert_after (block_stmt_iterator *, tree,
 468                               enum bsi_iterator_update);
 469
 470 extern void bsi_replace (const block_stmt_iterator *, tree, bool);
 471
 472 /*---------------------------------------------------------------------------
 473                               OpenMP Region Tree
 474 ---------------------------------------------------------------------------*/
 475
 476 /* Parallel region information.  Every parallel and workshare
 477    directive is enclosed between two markers, the OMP_* directive
 478    and a corresponding OMP_RETURN statement.  */
 479
 480 struct omp_region
 481 {
 482   /* The enclosing region.  */
 483   struct omp_region *outer;
 484
 485   /* First child region.  */
 486   struct omp_region *inner;
 487
 488   /* Next peer region.  */
 489   struct omp_region *next;
 490
 491   /* Block containing the omp directive as its last stmt.  */
 492   basic_block entry;
 493
 494   /* Block containing the OMP_RETURN as its last stmt.  */
 495   basic_block exit;
 496
 497   /* Block containing the OMP_CONTINUE as its last stmt.  */
 498   basic_block cont;
 499
 500   /* If this is a combined parallel+workshare region, this is a list
 501      of additional arguments needed by the combined parallel+workshare
 502      library call.  */
 503   tree ws_args;
 504
 505   /* The code for the omp directive of this region.  */
 506   enum tree_code type;
 507
 508   /* True if this is a combined parallel+workshare region.  */
 509   bool is_combined_parallel;
 510 };
 511
 512 extern struct omp_region *root_omp_region;
 513 extern struct omp_region *new_omp_region (basic_block, enum tree_code,
 514                                           struct omp_region *);
 515 extern void free_omp_regions (void);
 516
 517 /*---------------------------------------------------------------------------
 518                               Function prototypes
 519 ---------------------------------------------------------------------------*/
 520 /* In tree-cfg.c  */
 521
 522 /* Location to track pending stmt for edge insertion.  */
 523 #define PENDING_STMT(e) ((e)->insns.t)
 524
 525 extern void delete_tree_cfg_annotations (void);
 526 extern void disband_implicit_edges (void);
 527 extern bool stmt_ends_bb_p (tree);
 528 extern bool is_ctrl_stmt (tree);
 529 extern bool is_ctrl_altering_stmt (tree);
 530 extern bool computed_goto_p (tree);
 531 extern bool simple_goto_p (tree);
 532 extern basic_block single_noncomplex_succ (basic_block bb);
 533 extern void tree_dump_bb (basic_block, FILE *, int);
 534 extern void debug_tree_bb (basic_block);
 535 extern basic_block debug_tree_bb_n (int);
 536 extern void dump_tree_cfg (FILE *, int);
 537 extern void debug_tree_cfg (int);
 538 extern void dump_cfg_stats (FILE *);
 539 extern void debug_cfg_stats (void);
 540 extern void debug_loop_ir (void);
 541 extern void print_loop_ir (FILE *);
 542 extern void cleanup_dead_labels (void);
 543 extern void group_case_labels (void);
 544 extern tree first_stmt (basic_block);
 545 extern tree last_stmt (basic_block);
 546 extern tree *last_stmt_ptr (basic_block);
 547 extern tree last_and_only_stmt (basic_block);
 548 extern edge find_taken_edge (basic_block, tree);
 549 extern basic_block label_to_block_fn (struct function *, tree);
 550 #define label_to_block(t) (label_to_block_fn (cfun, t))
 551 extern void bsi_insert_on_edge (edge, tree);
 552 extern basic_block bsi_insert_on_edge_immediate (edge, tree);
 553 extern void bsi_commit_one_edge_insert (edge, basic_block *);
 554 extern void bsi_commit_edge_inserts (void);
 555 extern void notice_special_calls (tree);
 556 extern void clear_special_calls (void);
 557 extern void verify_stmts (void);
 558 extern tree tree_block_label (basic_block);
 559 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
 560 extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
 561                                         basic_block *);
 562 extern void add_phi_args_after_copy_bb (basic_block);
 563 extern void add_phi_args_after_copy (basic_block *, unsigned);
 564 extern bool tree_purge_dead_eh_edges (basic_block);
 565 extern bool tree_purge_all_dead_eh_edges (bitmap);
 566 extern tree gimplify_val (block_stmt_iterator *, tree, tree);
 567 extern tree gimplify_build1 (block_stmt_iterator *, enum tree_code,
 568                              tree, tree);
 569 extern tree gimplify_build2 (block_stmt_iterator *, enum tree_code,
 570                              tree, tree, tree);
 571 extern tree gimplify_build3 (block_stmt_iterator *, enum tree_code,
 572                              tree, tree, tree, tree);
 573 extern void init_empty_tree_cfg (void);
 574 extern void fold_cond_expr_cond (void);
 575 extern void replace_uses_by (tree, tree);
 576 extern void start_recording_case_labels (void);
 577 extern void end_recording_case_labels (void);
 578 extern basic_block move_sese_region_to_fn (struct function *, basic_block,
 579                                            basic_block);
 580
 581 /* In tree-cfgcleanup.c  */
 582 extern bool cleanup_tree_cfg (void);
 583 extern void cleanup_tree_cfg_loop (void);
 584
 585 /* In tree-pretty-print.c.  */
 586 extern void dump_generic_bb (FILE *, basic_block, int, int);
 587
 588 /* In tree-dfa.c  */
 589 extern var_ann_t create_var_ann (tree);
 590 extern function_ann_t create_function_ann (tree);
 591 extern stmt_ann_t create_stmt_ann (tree);
 592 extern tree_ann_t create_tree_ann (tree);
 593 extern void dump_dfa_stats (FILE *);
 594 extern void debug_dfa_stats (void);
 595 extern void debug_referenced_vars (void);
 596 extern void dump_referenced_vars (FILE *);
 597 extern void dump_variable (FILE *, tree);
 598 extern void debug_variable (tree);
 599 extern void dump_subvars_for (FILE *, tree);
 600 extern void debug_subvars_for (tree);
 601 extern tree get_virtual_var (tree);
 602 extern void add_referenced_tmp_var (tree);
 603 extern void mark_new_vars_to_rename (tree);
 604 extern void find_new_referenced_vars (tree *);
 605
 606 extern tree make_rename_temp (tree, const char *);
 607 extern void set_default_def (tree, tree);
 608 extern tree default_def (tree);
 609 extern tree default_def_fn (struct function *, tree);
 610
 611 /* In tree-phinodes.c  */
 612 extern void reserve_phi_args_for_new_edge (basic_block);
 613 extern tree create_phi_node (tree, basic_block);
 614 extern void add_phi_arg (tree, tree, edge);
 615 extern void remove_phi_args (edge);
 616 extern void remove_phi_node (tree, tree);
 617 extern tree phi_reverse (tree);
 618
 619 /* In gimple-low.c  */
 620 extern void record_vars_into (tree, tree);
 621 extern void record_vars (tree);
 622 extern bool block_may_fallthru (tree);
 623
 624 /* In tree-ssa-alias.c  */
 625 extern void dump_may_aliases_for (FILE *, tree);
 626 extern void debug_may_aliases_for (tree);
 627 extern void dump_alias_info (FILE *);
 628 extern void debug_alias_info (void);
 629 extern void dump_points_to_info (FILE *);
 630 extern void debug_points_to_info (void);
 631 extern void dump_points_to_info_for (FILE *, tree);
 632 extern void debug_points_to_info_for (tree);
 633 extern bool may_be_aliased (tree);
 634 extern bool is_aliased_with (tree, tree);
 635 extern struct ptr_info_def *get_ptr_info (tree);
 636 extern void add_type_alias (tree, tree);
 637 extern void new_type_alias (tree, tree);
 638 extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *, bool *);
 639 static inline subvar_t get_subvars_for_var (tree);
 640 static inline tree get_subvar_at (tree, unsigned HOST_WIDE_INT);
 641 static inline bool ref_contains_array_ref (tree);
 642 static inline bool array_ref_contains_indirect_ref (tree);
 643 extern tree get_ref_base_and_extent (tree, HOST_WIDE_INT *,
 644                                      HOST_WIDE_INT *, HOST_WIDE_INT *);
 645 static inline bool var_can_have_subvars (tree);
 646 static inline bool overlap_subvar (unsigned HOST_WIDE_INT,
 647                                    unsigned HOST_WIDE_INT,
 648                                    tree, bool *);
 649
 650 /* Call-back function for walk_use_def_chains().  At each reaching
 651    definition, a function with this prototype is called.  */
 652 typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
 653
 654
 655 /* In tree-ssa.c  */
 656 extern void init_tree_ssa (void);
 657 extern edge ssa_redirect_edge (edge, basic_block);
 658 extern void flush_pending_stmts (edge);
 659 extern bool tree_ssa_useless_type_conversion (tree);
 660 extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
 661 extern void verify_ssa (bool);
 662 extern void delete_tree_ssa (void);
 663 extern void register_new_def (tree, VEC(tree,heap) **);
 664 extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *, bool);
 665 extern bool stmt_references_memory_p (tree);
 666
 667 /* In tree-into-ssa.c  */
 668 void update_ssa (unsigned);
 669 void delete_update_ssa (void);
 670 void register_new_name_mapping (tree, tree);
 671 tree create_new_def_for (tree, tree, def_operand_p);
 672 bool need_ssa_update_p (void);
 673 bool name_registered_for_update_p (tree);
 674 bitmap ssa_names_to_replace (void);
 675 void release_ssa_name_after_update_ssa (tree name);
 676 void compute_global_livein (bitmap, bitmap);
 677 tree duplicate_ssa_name (tree, tree);
 678 void mark_sym_for_renaming (tree);
 679 void mark_set_for_renaming (bitmap);
 680 tree get_current_def (tree);
 681 void set_current_def (tree, tree);
 682
 683 /* In tree-ssa-ccp.c  */
 684 bool fold_stmt (tree *);
 685 bool fold_stmt_inplace (tree);
 686 tree widen_bitfield (tree, tree, tree);
 687
 688 /* In tree-vrp.c  */
 689 tree vrp_evaluate_conditional (tree, bool);
 690 void simplify_stmt_using_ranges (tree);
 691
 692 /* In tree-ssa-dom.c  */
 693 extern void dump_dominator_optimization_stats (FILE *);
 694 extern void debug_dominator_optimization_stats (void);
 695 int loop_depth_of_name (tree);
 696
 697 /* In tree-ssa-copy.c  */
 698 extern void merge_alias_info (tree, tree);
 699 extern void propagate_value (use_operand_p, tree);
 700 extern void propagate_tree_value (tree *, tree);
 701 extern void replace_exp (use_operand_p, tree);
 702 extern bool may_propagate_copy (tree, tree);
 703 extern bool may_propagate_copy_into_asm (tree);
 704
 705 /* Affine iv.  */
 706
 707 typedef struct
 708 {
 709   /* Iv = BASE + STEP * i.  */
 710   tree base, step;
 711
 712   /* True if this iv does not overflow.  */
 713   bool no_overflow;
 714 } affine_iv;
 715
 716 /* Description of number of iterations of a loop.  All the expressions inside
 717    the structure can be evaluated at the end of the loop's preheader
 718    (and due to ssa form, also anywhere inside the body of the loop).  */
 719
 720 struct tree_niter_desc
 721 {
 722   tree assumptions;     /* The boolean expression.  If this expression evaluates
 723                            to false, then the other fields in this structure
 724                            should not be used; there is no guarantee that they
 725                            will be correct.  */
 726   tree may_be_zero;     /* The boolean expression.  If it evaluates to true,
 727                            the loop will exit in the first iteration (i.e.
 728                            its latch will not be executed), even if the niter
 729                            field says otherwise.  */
 730   tree niter;           /* The expression giving the number of iterations of
 731                            a loop (provided that assumptions == true and
 732                            may_be_zero == false), more precisely the number
 733                            of executions of the latch of the loop.  */
 734   tree additional_info; /* The boolean expression.  Sometimes we use additional
 735                            knowledge to simplify the other expressions
 736                            contained in this structure (for example the
 737                            knowledge about value ranges of operands on entry to
 738                            the loop).  If this is a case, conjunction of such
 739                            condition is stored in this field, so that we do not
 740                            lose the information: for example if may_be_zero
 741                            is (n <= 0) and niter is (unsigned) n, we know
 742                            that the number of iterations is at most
 743                            MAX_SIGNED_INT.  However if the (n <= 0) assumption
 744                            is eliminated (by looking at the guard on entry of
 745                            the loop), then the information would be lost.  */
 746
 747   /* The simplified shape of the exit condition.  The loop exits if
 748      CONTROL CMP BOUND is false, where CMP is one of NE_EXPR,
 749      LT_EXPR, or GT_EXPR, and step of CONTROL is positive if CMP is
 750      LE_EXPR and negative if CMP is GE_EXPR.  This information is used
 751      by loop unrolling.  */
 752   affine_iv control;
 753   tree bound;
 754   enum tree_code cmp;
 755 };
 756
 757 /* In tree-vectorizer.c */
 758 void vectorize_loops (struct loops *);
 759
 760 /* In tree-ssa-phiopt.c */
 761 bool empty_block_p (basic_block);
 762
 763 /* In tree-ssa-loop*.c  */
 764
 765 void tree_ssa_lim (struct loops *);
 766 void tree_ssa_unswitch_loops (struct loops *);
 767 void canonicalize_induction_variables (struct loops *);
 768 void tree_unroll_loops_completely (struct loops *, bool);
 769 void tree_ssa_prefetch_arrays (struct loops *);
 770 void remove_empty_loops (struct loops *);
 771 void tree_ssa_iv_optimize (struct loops *);
 772
 773 bool number_of_iterations_exit (struct loop *, edge,
 774                                 struct tree_niter_desc *niter, bool);
 775 tree find_loop_niter (struct loop *, edge *);
 776 tree loop_niter_by_eval (struct loop *, edge);
 777 tree find_loop_niter_by_eval (struct loop *, edge *);
 778 void estimate_numbers_of_iterations (struct loops *);
 779 bool scev_probably_wraps_p (tree, tree, tree, tree, struct loop *, bool *,
 780                             bool *);
 781 tree convert_step (struct loop *, tree, tree, tree, tree);
 782 void free_numbers_of_iterations_estimates (struct loops *);
 783 void free_numbers_of_iterations_estimates_loop (struct loop *);
 784 void rewrite_into_loop_closed_ssa (bitmap, unsigned);
 785 void verify_loop_closed_ssa (void);
 786 void loop_commit_inserts (void);
 787 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
 788 void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
 789                 tree *, tree *);
 790 void split_loop_exit_edge (edge);
 791 void compute_phi_arg_on_exit (edge, tree, tree);
 792 unsigned force_expr_to_var_cost (tree);
 793 basic_block bsi_insert_on_edge_immediate_loop (edge, tree);
 794 void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
 795                                      bool *);
 796 basic_block ip_end_pos (struct loop *);
 797 basic_block ip_normal_pos (struct loop *);
 798 bool tree_duplicate_loop_to_header_edge (struct loop *, edge, struct loops *,
 799                                          unsigned int, sbitmap,
 800                                          edge, edge *,
 801                                          unsigned int *, int);
 802 struct loop *tree_ssa_loop_version (struct loops *, struct loop *, tree,
 803                                     basic_block *);
 804 tree expand_simple_operations (tree);
 805 void substitute_in_loop_info (struct loop *, tree, tree);
 806 edge single_dom_exit (struct loop *);
 807 bool can_unroll_loop_p (struct loop *loop, unsigned factor,
 808                         struct tree_niter_desc *niter);
 809 void tree_unroll_loop (struct loops *, struct loop *, unsigned,
 810                        edge, struct tree_niter_desc *);
 811
 812 /* In tree-ssa-threadedge.c */
 813 extern bool potentially_threadable_block (basic_block);
 814 extern void thread_across_edge (tree, edge, bool,
 815                                 VEC(tree, heap) **, tree (*) (tree));
 816
 817 /* In tree-ssa-loop-im.c  */
 818 /* The possibilities of statement movement.  */
 819
 820 enum move_pos
 821   {
 822     MOVE_IMPOSSIBLE,            /* No movement -- side effect expression.  */
 823     MOVE_PRESERVE_EXECUTION,    /* Must not cause the non-executed statement
 824                                    become executed -- memory accesses, ... */
 825     MOVE_POSSIBLE               /* Unlimited movement.  */
 826   };
 827 extern enum move_pos movement_possibility (tree);
 828
 829 /* The reasons a variable may escape a function.  */
 830 enum escape_type
 831   {
 832     NO_ESCAPE = 0, /* Doesn't escape.  */
 833     ESCAPE_STORED_IN_GLOBAL = 1 << 1,
 834     ESCAPE_TO_ASM = 1 << 2,  /* Passed by address to an assembly
 835                                 statement.  */
 836     ESCAPE_TO_CALL = 1 << 3,  /* Escapes to a function call.  */
 837     ESCAPE_BAD_CAST = 1 << 4, /* Cast from pointer to integer */
 838     ESCAPE_TO_RETURN = 1 << 5, /* Returned from function.  */
 839     ESCAPE_TO_PURE_CONST = 1 << 6, /* Escapes to a pure or constant
 840                                       function call.  */
 841     ESCAPE_IS_GLOBAL = 1 << 7,  /* Is a global variable.  */
 842     ESCAPE_IS_PARM = 1 << 8, /* Is an incoming function parameter.  */
 843     ESCAPE_UNKNOWN = 1 << 9 /* We believe it escapes for some reason
 844                                not enumerated above.  */
 845   };
 846
 847 /* In tree-flow-inline.h  */
 848 static inline bool is_call_clobbered (tree);
 849 static inline void mark_call_clobbered (tree, unsigned int);
 850 static inline void set_is_used (tree);
 851 static inline bool unmodifiable_var_p (tree);
 852
 853 /* In tree-eh.c  */
 854 extern void make_eh_edges (tree);
 855 extern bool tree_could_trap_p (tree);
 856 extern bool tree_could_throw_p (tree);
 857 extern bool tree_can_throw_internal (tree);
 858 extern bool tree_can_throw_external (tree);
 859 extern int lookup_stmt_eh_region (tree);
 860 extern void add_stmt_to_eh_region (tree, int);
 861 extern bool remove_stmt_from_eh_region (tree);
 862 extern bool maybe_clean_or_replace_eh_stmt (tree, tree);
 863
 864 /* In tree-ssa-pre.c  */
 865 void add_to_value (tree, tree);
 866 void debug_value_expressions (tree);
 867 void print_value_expressions (FILE *, tree);
 868
 869
 870 /* In tree-vn.c  */
 871 bool expressions_equal_p (tree, tree);
 872 tree get_value_handle (tree);
 873 hashval_t vn_compute (tree, hashval_t);
 874 void sort_vuses (VEC (tree, gc) *);
 875 tree vn_lookup_or_add (tree, tree);
 876 tree vn_lookup_or_add_with_vuses (tree, VEC (tree, gc) *);
 877 void vn_add (tree, tree);
 878 void vn_add_with_vuses (tree, tree, VEC (tree, gc) *);
 879 tree vn_lookup (tree, tree);
 880 tree vn_lookup_with_vuses (tree, VEC (tree, gc) *);
 881 void vn_init (void);
 882 void vn_delete (void);
 883
 884 /* In tree-ssa-sink.c  */
 885 bool is_hidden_global_store (tree);
 886
 887 /* In tree-sra.c  */
 888 void insert_edge_copies (tree, basic_block);
 889 void sra_insert_before (block_stmt_iterator *, tree);
 890 void sra_insert_after (block_stmt_iterator *, tree);
 891 void sra_init_cache (void);
 892 bool sra_type_can_be_decomposed_p (tree);
 893
 894 /* In tree-loop-linear.c  */
 895 extern void linear_transform_loops (struct loops *);
 896
 897 /* In tree-ssa-loop-ivopts.c  */
 898 bool expr_invariant_in_loop_p (struct loop *, tree);
 899 bool multiplier_allowed_in_address_p (HOST_WIDE_INT);
 900 unsigned multiply_by_cost (HOST_WIDE_INT, enum machine_mode);
 901
 902 /* In tree-ssa-threadupdate.c.  */
 903 extern bool thread_through_all_blocks (void);
 904 extern void register_jump_thread (edge, edge);
 905
 906 /* In gimplify.c  */
 907 tree force_gimple_operand (tree, tree *, bool, tree);
 908 tree force_gimple_operand_bsi (block_stmt_iterator *, tree, bool, tree);
 909
 910 /* In tree-ssa-structalias.c */
 911 bool find_what_p_points_to (tree);
 912
 913 /* In tree-ssa-live.c */
 914 extern void remove_unused_locals (void);
 915
 916 /* In tree-ssa-address.c  */
 917
 918 /* Affine combination of trees.  We keep track of at most MAX_AFF_ELTS elements
 919    to make things simpler; this is sufficient in most cases.  */
 920
 921 #define MAX_AFF_ELTS 8
 922
 923 struct affine_tree_combination
 924 {
 925   /* Type of the result of the combination.  */
 926   tree type;
 927
 928   /* Mask modulo that the operations are performed.  */
 929   unsigned HOST_WIDE_INT mask;
 930
 931   /* Constant offset.  */
 932   unsigned HOST_WIDE_INT offset;
 933
 934   /* Number of elements of the combination.  */
 935   unsigned n;
 936
 937   /* Elements and their coefficients.  */
 938   tree elts[MAX_AFF_ELTS];
 939   unsigned HOST_WIDE_INT coefs[MAX_AFF_ELTS];
 940
 941   /* Remainder of the expression.  */
 942   tree rest;
 943 };
 944
 945 /* Description of a memory address.  */
 946
 947 struct mem_address
 948 {
 949   tree symbol, base, index, step, offset;
 950 };
 951
 952 tree create_mem_ref (block_stmt_iterator *, tree,
 953                      struct affine_tree_combination *);
 954 rtx addr_for_mem_ref (struct mem_address *, bool);
 955 void get_address_description (tree, struct mem_address *);
 956 tree maybe_fold_tmr (tree);
 957
 958 /* This structure is simply used during pushing fields onto the fieldstack
 959    to track the offset of the field, since bitpos_of_field gives it relative
 960    to its immediate containing type, and we want it relative to the ultimate
 961    containing object.  */
 962
 963 struct fieldoff
 964 {
 965   tree type;
 966   tree size;
 967   tree decl;
 968   HOST_WIDE_INT offset;
 969 };
 970 typedef struct fieldoff fieldoff_s;
 971
 972 DEF_VEC_O(fieldoff_s);
 973 DEF_VEC_ALLOC_O(fieldoff_s,heap);
 974 int push_fields_onto_fieldstack (tree, VEC(fieldoff_s,heap) **,
 975                                  HOST_WIDE_INT, bool *);
 976 void sort_fieldstack (VEC(fieldoff_s,heap) *);
 977
 978 void init_alias_heapvars (void);
 979 void delete_alias_heapvars (void);
 980
 981 #include "tree-flow-inline.h"
 982
 983 void swap_tree_operands (tree, tree *, tree *);
 984
 985 extern void recalculate_used_alone (void);
 986 extern bool updating_used_alone;
 987 #endif /* _TREE_FLOW_H  */