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   /* 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
 285 struct 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
 321 union 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
 329 extern GTY(()) VEC(tree,gc) *modified_noreturn_calls;
 330
 331 typedef union tree_ann_d *tree_ann_t;
 332 typedef struct var_ann_d *var_ann_t;
 333 typedef struct function_ann_d *function_ann_t;
 334 typedef struct stmt_ann_d *stmt_ann_t;
 335
 336 static inline tree_ann_t tree_ann (tree);
 337 static inline tree_ann_t get_tree_ann (tree);
 338 static inline var_ann_t var_ann (tree);
 339 static inline var_ann_t get_var_ann (tree);
 340 static inline function_ann_t function_ann (tree);
 341 static inline function_ann_t get_function_ann (tree);
 342 static inline stmt_ann_t stmt_ann (tree);
 343 static inline stmt_ann_t get_stmt_ann (tree);
 344 static inline enum tree_ann_type ann_type (tree_ann_t);
 345 static inline basic_block bb_for_stmt (tree);
 346 extern void set_bb_for_stmt (tree, basic_block);
 347 static inline bool noreturn_call_p (tree);
 348 static inline void update_stmt (tree);
 349 static inline bool stmt_modified_p (tree);
 350 static inline VEC(tree, gc) *may_aliases (tree);
 351 static inline int get_lineno (tree);
 352 static inline const char *get_filename (tree);
 353 static inline bool is_exec_stmt (tree);
 354 static inline bool is_label_stmt (tree);
 355 static inline bitmap addresses_taken (tree);
 356
 357 /*---------------------------------------------------------------------------
 358                   Structure representing predictions in tree level.
 359 ---------------------------------------------------------------------------*/
 360 struct edge_prediction GTY((chain_next ("%h.ep_next")))
 361 {
 362   struct edge_prediction *ep_next;
 363   edge ep_edge;
 364   enum br_predictor ep_predictor;
 365   int ep_probability;
 366 };
 367
 368 /* Accessors for basic block annotations.  */
 369 static inline tree phi_nodes (basic_block);
 370 static inline void set_phi_nodes (basic_block, tree);
 371
 372 /*---------------------------------------------------------------------------
 373                               Global declarations
 374 ---------------------------------------------------------------------------*/
 375 struct int_tree_map GTY(())
 376 {
 377
 378   unsigned int uid;
 379   tree to;
 380 };
 381
 382 extern unsigned int int_tree_map_hash (const void *);
 383 extern int int_tree_map_eq (const void *, const void *);
 384
 385 typedef struct
 386 {
 387   htab_iterator hti;
 388 } referenced_var_iterator;
 389
 390
 391 /* This macro loops over all the referenced vars, one at a time, putting the
 392    current var in VAR.  Note:  You are not allowed to add referenced variables
 393    to the hashtable while using this macro.  Doing so may cause it to behave
 394    erratically.  */
 395
 396 #define FOR_EACH_REFERENCED_VAR(VAR, ITER) \
 397   for ((VAR) = first_referenced_var (&(ITER)); \
 398        !end_referenced_vars_p (&(ITER)); \
 399        (VAR) = next_referenced_var (&(ITER)))
 400
 401
 402 typedef struct
 403 {
 404   int i;
 405 } safe_referenced_var_iterator;
 406
 407 /* This macro loops over all the referenced vars, one at a time, putting the
 408    current var in VAR.  You are allowed to add referenced variables during the
 409    execution of this macro, however, the macro will not iterate over them.  It
 410    requires a temporary vector of trees, VEC, whose lifetime is controlled by
 411    the caller.  The purpose of the vector is to temporarily store the
 412    referenced_variables hashtable so that adding referenced variables does not
 413    affect the hashtable.  */
 414
 415 #define FOR_EACH_REFERENCED_VAR_SAFE(VAR, VEC, ITER) \
 416   for ((ITER).i = 0, fill_referenced_var_vec (&(VEC)); \
 417        VEC_iterate (tree, (VEC), (ITER).i, (VAR)); \
 418        (ITER).i++)
 419
 420 /* Array of all variables referenced in the function.  */
 421 extern GTY((param_is (struct int_tree_map))) htab_t referenced_vars;
 422
 423 /* Default defs for undefined symbols. */
 424 extern GTY((param_is (struct int_tree_map))) htab_t default_defs;
 425
 426 extern tree referenced_var_lookup (unsigned int);
 427 #define num_referenced_vars htab_elements (referenced_vars)
 428 #define referenced_var(i) referenced_var_lookup (i)
 429
 430 /* Array of all SSA_NAMEs used in the function.  */
 431 extern GTY(()) VEC(tree,gc) *ssa_names;
 432
 433 #define num_ssa_names (VEC_length (tree, ssa_names))
 434 #define ssa_name(i) (VEC_index (tree, ssa_names, (i)))
 435
 436 /* Artificial variable used to model the effects of function calls.  */
 437 extern GTY(()) tree global_var;
 438
 439 /* Call clobbered variables in the function.  If bit I is set, then
 440    REFERENCED_VARS (I) is call-clobbered.  */
 441 extern bitmap call_clobbered_vars;
 442
 443 /* Addressable variables in the function.  If bit I is set, then
 444    REFERENCED_VARS (I) has had its address taken.  */
 445 extern bitmap addressable_vars;
 446
 447 /* 'true' after aliases have been computed (see compute_may_aliases).  */
 448 extern bool aliases_computed_p;
 449
 450 /* Macros for showing usage statistics.  */
 451 #define SCALE(x) ((unsigned long) ((x) < 1024*10        \
 452                   ? (x)                                 \
 453                   : ((x) < 1024*1024*10                 \
 454                      ? (x) / 1024                       \
 455                      : (x) / (1024*1024))))
 456
 457 #define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
 458
 459 #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
 460
 461 /*---------------------------------------------------------------------------
 462                               Block iterators
 463 ---------------------------------------------------------------------------*/
 464
 465 typedef struct {
 466   tree_stmt_iterator tsi;
 467   basic_block bb;
 468 } block_stmt_iterator;
 469
 470 static inline block_stmt_iterator bsi_start (basic_block);
 471 static inline block_stmt_iterator bsi_last (basic_block);
 472 static inline block_stmt_iterator bsi_after_labels (basic_block);
 473 block_stmt_iterator bsi_for_stmt (tree);
 474 static inline bool bsi_end_p (block_stmt_iterator);
 475 static inline void bsi_next (block_stmt_iterator *);
 476 static inline void bsi_prev (block_stmt_iterator *);
 477 static inline tree bsi_stmt (block_stmt_iterator);
 478 static inline tree * bsi_stmt_ptr (block_stmt_iterator);
 479
 480 extern void bsi_remove (block_stmt_iterator *, bool);
 481 extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
 482 extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
 483 extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
 484
 485 enum bsi_iterator_update
 486 {
 487   /* Note that these are intentionally in the same order as TSI_FOO.  They
 488      mean exactly the same as their TSI_* counterparts.  */
 489   BSI_NEW_STMT,
 490   BSI_SAME_STMT,
 491   BSI_CHAIN_START,
 492   BSI_CHAIN_END,
 493   BSI_CONTINUE_LINKING
 494 };
 495
 496 extern void bsi_insert_before (block_stmt_iterator *, tree,
 497                                enum bsi_iterator_update);
 498 extern void bsi_insert_after (block_stmt_iterator *, tree,
 499                               enum bsi_iterator_update);
 500
 501 extern void bsi_replace (const block_stmt_iterator *, tree, bool);
 502
 503 /*---------------------------------------------------------------------------
 504                               OpenMP Region Tree
 505 ---------------------------------------------------------------------------*/
 506
 507 /* Parallel region information.  Every parallel and workshare
 508    directive is enclosed between two markers, the OMP_* directive
 509    and a corresponding OMP_RETURN statement.  */
 510
 511 struct omp_region
 512 {
 513   /* The enclosing region.  */
 514   struct omp_region *outer;
 515
 516   /* First child region.  */
 517   struct omp_region *inner;
 518
 519   /* Next peer region.  */
 520   struct omp_region *next;
 521
 522   /* Block containing the omp directive as its last stmt.  */
 523   basic_block entry;
 524
 525   /* Block containing the OMP_RETURN as its last stmt.  */
 526   basic_block exit;
 527
 528   /* Block containing the OMP_CONTINUE as its last stmt.  */
 529   basic_block cont;
 530
 531   /* If this is a combined parallel+workshare region, this is a list
 532      of additional arguments needed by the combined parallel+workshare
 533      library call.  */
 534   tree ws_args;
 535
 536   /* The code for the omp directive of this region.  */
 537   enum tree_code type;
 538
 539   /* Schedule kind, only used for OMP_FOR type regions.  */
 540   enum omp_clause_schedule_kind sched_kind;
 541
 542   /* True if this is a combined parallel+workshare region.  */
 543   bool is_combined_parallel;
 544 };
 545
 546 extern struct omp_region *root_omp_region;
 547 extern struct omp_region *new_omp_region (basic_block, enum tree_code,
 548                                           struct omp_region *);
 549 extern void free_omp_regions (void);
 550
 551 /*---------------------------------------------------------------------------
 552                               Function prototypes
 553 ---------------------------------------------------------------------------*/
 554 /* In tree-cfg.c  */
 555
 556 /* Location to track pending stmt for edge insertion.  */
 557 #define PENDING_STMT(e) ((e)->insns.t)
 558
 559 extern void delete_tree_cfg_annotations (void);
 560 extern void disband_implicit_edges (void);
 561 extern bool stmt_ends_bb_p (tree);
 562 extern bool is_ctrl_stmt (tree);
 563 extern bool is_ctrl_altering_stmt (tree);
 564 extern bool computed_goto_p (tree);
 565 extern bool simple_goto_p (tree);
 566 extern basic_block single_noncomplex_succ (basic_block bb);
 567 extern void tree_dump_bb (basic_block, FILE *, int);
 568 extern void debug_tree_bb (basic_block);
 569 extern basic_block debug_tree_bb_n (int);
 570 extern void dump_tree_cfg (FILE *, int);
 571 extern void debug_tree_cfg (int);
 572 extern void dump_cfg_stats (FILE *);
 573 extern void debug_cfg_stats (void);
 574 extern void debug_loop_ir (void);
 575 extern void print_loop_ir (FILE *);
 576 extern void cleanup_dead_labels (void);
 577 extern void group_case_labels (void);
 578 extern tree first_stmt (basic_block);
 579 extern tree last_stmt (basic_block);
 580 extern tree *last_stmt_ptr (basic_block);
 581 extern tree last_and_only_stmt (basic_block);
 582 extern edge find_taken_edge (basic_block, tree);
 583 extern basic_block label_to_block_fn (struct function *, tree);
 584 #define label_to_block(t) (label_to_block_fn (cfun, t))
 585 extern void bsi_insert_on_edge (edge, tree);
 586 extern basic_block bsi_insert_on_edge_immediate (edge, tree);
 587 extern void bsi_commit_one_edge_insert (edge, basic_block *);
 588 extern void bsi_commit_edge_inserts (void);
 589 extern void notice_special_calls (tree);
 590 extern void clear_special_calls (void);
 591 extern void verify_stmts (void);
 592 extern tree tree_block_label (basic_block);
 593 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
 594 extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
 595                                         basic_block *);
 596 extern void add_phi_args_after_copy_bb (basic_block);
 597 extern void add_phi_args_after_copy (basic_block *, unsigned);
 598 extern bool tree_purge_dead_eh_edges (basic_block);
 599 extern bool tree_purge_all_dead_eh_edges (bitmap);
 600 extern tree gimplify_val (block_stmt_iterator *, tree, tree);
 601 extern tree gimplify_build1 (block_stmt_iterator *, enum tree_code,
 602                              tree, tree);
 603 extern tree gimplify_build2 (block_stmt_iterator *, enum tree_code,
 604                              tree, tree, tree);
 605 extern tree gimplify_build3 (block_stmt_iterator *, enum tree_code,
 606                              tree, tree, tree, tree);
 607 extern void init_empty_tree_cfg (void);
 608 extern void fold_cond_expr_cond (void);
 609 extern void replace_uses_by (tree, tree);
 610 extern void start_recording_case_labels (void);
 611 extern void end_recording_case_labels (void);
 612 extern basic_block move_sese_region_to_fn (struct function *, basic_block,
 613                                            basic_block);
 614
 615 /* In tree-cfgcleanup.c  */
 616 extern bool cleanup_tree_cfg (void);
 617 extern void cleanup_tree_cfg_loop (void);
 618
 619 /* In tree-pretty-print.c.  */
 620 extern void dump_generic_bb (FILE *, basic_block, int, int);
 621
 622 /* In tree-dfa.c  */
 623 extern var_ann_t create_var_ann (tree);
 624 extern function_ann_t create_function_ann (tree);
 625 extern stmt_ann_t create_stmt_ann (tree);
 626 extern tree_ann_t create_tree_ann (tree);
 627 extern void dump_dfa_stats (FILE *);
 628 extern void debug_dfa_stats (void);
 629 extern void debug_referenced_vars (void);
 630 extern void dump_referenced_vars (FILE *);
 631 extern void dump_variable (FILE *, tree);
 632 extern void debug_variable (tree);
 633 extern void dump_subvars_for (FILE *, tree);
 634 extern void debug_subvars_for (tree);
 635 extern tree get_virtual_var (tree);
 636 extern void add_referenced_var (tree);
 637 extern void mark_new_vars_to_rename (tree);
 638 extern void find_new_referenced_vars (tree *);
 639
 640 extern tree make_rename_temp (tree, const char *);
 641 extern void set_default_def (tree, tree);
 642 extern tree default_def (tree);
 643 extern tree default_def_fn (struct function *, tree);
 644
 645 /* In tree-phinodes.c  */
 646 extern void reserve_phi_args_for_new_edge (basic_block);
 647 extern tree create_phi_node (tree, basic_block);
 648 extern void add_phi_arg (tree, tree, edge);
 649 extern void remove_phi_args (edge);
 650 extern void remove_phi_node (tree, tree);
 651 extern tree phi_reverse (tree);
 652
 653 /* In gimple-low.c  */
 654 extern void record_vars_into (tree, tree);
 655 extern void record_vars (tree);
 656 extern bool block_may_fallthru (tree);
 657
 658 /* In tree-ssa-alias.c  */
 659 extern void dump_may_aliases_for (FILE *, tree);
 660 extern void debug_may_aliases_for (tree);
 661 extern void dump_alias_info (FILE *);
 662 extern void debug_alias_info (void);
 663 extern void dump_points_to_info (FILE *);
 664 extern void debug_points_to_info (void);
 665 extern void dump_points_to_info_for (FILE *, tree);
 666 extern void debug_points_to_info_for (tree);
 667 extern bool may_be_aliased (tree);
 668 extern bool is_aliased_with (tree, tree);
 669 extern struct ptr_info_def *get_ptr_info (tree);
 670 extern void add_type_alias (tree, tree);
 671 extern void new_type_alias (tree, tree);
 672 extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *, bool *);
 673 static inline subvar_t get_subvars_for_var (tree);
 674 static inline tree get_subvar_at (tree, unsigned HOST_WIDE_INT);
 675 static inline bool ref_contains_array_ref (tree);
 676 static inline bool array_ref_contains_indirect_ref (tree);
 677 extern tree get_ref_base_and_extent (tree, HOST_WIDE_INT *,
 678                                      HOST_WIDE_INT *, HOST_WIDE_INT *);
 679 static inline bool var_can_have_subvars (tree);
 680 static inline bool overlap_subvar (unsigned HOST_WIDE_INT,
 681                                    unsigned HOST_WIDE_INT,
 682                                    tree, bool *);
 683
 684 /* Call-back function for walk_use_def_chains().  At each reaching
 685    definition, a function with this prototype is called.  */
 686 typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
 687
 688
 689 /* In tree-ssa.c  */
 690 extern void init_tree_ssa (void);
 691 extern edge ssa_redirect_edge (edge, basic_block);
 692 extern void flush_pending_stmts (edge);
 693 extern bool tree_ssa_useless_type_conversion (tree);
 694 extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
 695 extern void verify_ssa (bool);
 696 extern void delete_tree_ssa (void);
 697 extern void register_new_def (tree, VEC(tree,heap) **);
 698 extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *, bool);
 699 extern bool stmt_references_memory_p (tree);
 700
 701 /* In tree-into-ssa.c  */
 702 void update_ssa (unsigned);
 703 void delete_update_ssa (void);
 704 void register_new_name_mapping (tree, tree);
 705 tree create_new_def_for (tree, tree, def_operand_p);
 706 bool need_ssa_update_p (void);
 707 bool name_registered_for_update_p (tree);
 708 bitmap ssa_names_to_replace (void);
 709 void release_ssa_name_after_update_ssa (tree name);
 710 void compute_global_livein (bitmap, bitmap);
 711 tree duplicate_ssa_name (tree, tree);
 712 void mark_sym_for_renaming (tree);
 713 void mark_set_for_renaming (bitmap);
 714 tree get_current_def (tree);
 715 void set_current_def (tree, tree);
 716
 717 /* In tree-ssa-ccp.c  */
 718 bool fold_stmt (tree *);
 719 bool fold_stmt_inplace (tree);
 720 tree widen_bitfield (tree, tree, tree);
 721
 722 /* In tree-vrp.c  */
 723 tree vrp_evaluate_conditional (tree, bool);
 724 void simplify_stmt_using_ranges (tree);
 725
 726 /* In tree-ssa-dom.c  */
 727 extern void dump_dominator_optimization_stats (FILE *);
 728 extern void debug_dominator_optimization_stats (void);
 729 int loop_depth_of_name (tree);
 730
 731 /* In tree-ssa-copy.c  */
 732 extern void merge_alias_info (tree, tree);
 733 extern void propagate_value (use_operand_p, tree);
 734 extern void propagate_tree_value (tree *, tree);
 735 extern void replace_exp (use_operand_p, tree);
 736 extern bool may_propagate_copy (tree, tree);
 737 extern bool may_propagate_copy_into_asm (tree);
 738
 739 /* Affine iv.  */
 740
 741 typedef struct
 742 {
 743   /* Iv = BASE + STEP * i.  */
 744   tree base, step;
 745
 746   /* True if this iv does not overflow.  */
 747   bool no_overflow;
 748 } affine_iv;
 749
 750 /* Description of number of iterations of a loop.  All the expressions inside
 751    the structure can be evaluated at the end of the loop's preheader
 752    (and due to ssa form, also anywhere inside the body of the loop).  */
 753
 754 struct tree_niter_desc
 755 {
 756   tree assumptions;     /* The boolean expression.  If this expression evaluates
 757                            to false, then the other fields in this structure
 758                            should not be used; there is no guarantee that they
 759                            will be correct.  */
 760   tree may_be_zero;     /* The boolean expression.  If it evaluates to true,
 761                            the loop will exit in the first iteration (i.e.
 762                            its latch will not be executed), even if the niter
 763                            field says otherwise.  */
 764   tree niter;           /* The expression giving the number of iterations of
 765                            a loop (provided that assumptions == true and
 766                            may_be_zero == false), more precisely the number
 767                            of executions of the latch of the loop.  */
 768   tree additional_info; /* The boolean expression.  Sometimes we use additional
 769                            knowledge to simplify the other expressions
 770                            contained in this structure (for example the
 771                            knowledge about value ranges of operands on entry to
 772                            the loop).  If this is a case, conjunction of such
 773                            condition is stored in this field, so that we do not
 774                            lose the information: for example if may_be_zero
 775                            is (n <= 0) and niter is (unsigned) n, we know
 776                            that the number of iterations is at most
 777                            MAX_SIGNED_INT.  However if the (n <= 0) assumption
 778                            is eliminated (by looking at the guard on entry of
 779                            the loop), then the information would be lost.  */
 780
 781   /* The simplified shape of the exit condition.  The loop exits if
 782      CONTROL CMP BOUND is false, where CMP is one of NE_EXPR,
 783      LT_EXPR, or GT_EXPR, and step of CONTROL is positive if CMP is
 784      LE_EXPR and negative if CMP is GE_EXPR.  This information is used
 785      by loop unrolling.  */
 786   affine_iv control;
 787   tree bound;
 788   enum tree_code cmp;
 789 };
 790
 791 /* In tree-vectorizer.c */
 792 void vectorize_loops (struct loops *);
 793
 794 /* In tree-ssa-phiopt.c */
 795 bool empty_block_p (basic_block);
 796
 797 /* In tree-ssa-loop*.c  */
 798
 799 void tree_ssa_lim (struct loops *);
 800 void tree_ssa_unswitch_loops (struct loops *);
 801 void canonicalize_induction_variables (struct loops *);
 802 void tree_unroll_loops_completely (struct loops *, bool);
 803 void tree_ssa_prefetch_arrays (struct loops *);
 804 void remove_empty_loops (struct loops *);
 805 void tree_ssa_iv_optimize (struct loops *);
 806
 807 bool number_of_iterations_exit (struct loop *, edge,
 808                                 struct tree_niter_desc *niter, bool);
 809 tree find_loop_niter (struct loop *, edge *);
 810 tree loop_niter_by_eval (struct loop *, edge);
 811 tree find_loop_niter_by_eval (struct loop *, edge *);
 812 void estimate_numbers_of_iterations (struct loops *);
 813 bool scev_probably_wraps_p (tree, tree, tree, struct loop *, bool);
 814 bool convert_affine_scev (struct loop *, tree, tree *, tree *, tree, bool);
 815
 816 bool nowrap_type_p (tree);
 817 enum ev_direction {EV_DIR_GROWS, EV_DIR_DECREASES, EV_DIR_UNKNOWN};
 818 enum ev_direction scev_direction (tree);
 819
 820 void free_numbers_of_iterations_estimates (struct loops *);
 821 void free_numbers_of_iterations_estimates_loop (struct loop *);
 822 void rewrite_into_loop_closed_ssa (bitmap, unsigned);
 823 void verify_loop_closed_ssa (void);
 824 void loop_commit_inserts (void);
 825 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
 826 void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
 827                 tree *, tree *);
 828 void split_loop_exit_edge (edge);
 829 void compute_phi_arg_on_exit (edge, tree, tree);
 830 unsigned force_expr_to_var_cost (tree);
 831 basic_block bsi_insert_on_edge_immediate_loop (edge, tree);
 832 void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
 833                                      bool *);
 834 basic_block ip_end_pos (struct loop *);
 835 basic_block ip_normal_pos (struct loop *);
 836 bool tree_duplicate_loop_to_header_edge (struct loop *, edge, struct loops *,
 837                                          unsigned int, sbitmap,
 838                                          edge, edge *,
 839                                          unsigned int *, int);
 840 struct loop *tree_ssa_loop_version (struct loops *, struct loop *, tree,
 841                                     basic_block *);
 842 tree expand_simple_operations (tree);
 843 void substitute_in_loop_info (struct loop *, tree, tree);
 844 edge single_dom_exit (struct loop *);
 845 bool can_unroll_loop_p (struct loop *loop, unsigned factor,
 846                         struct tree_niter_desc *niter);
 847 void tree_unroll_loop (struct loops *, struct loop *, unsigned,
 848                        edge, struct tree_niter_desc *);
 849 bool contains_abnormal_ssa_name_p (tree);
 850
 851 /* In tree-ssa-threadedge.c */
 852 extern bool potentially_threadable_block (basic_block);
 853 extern void thread_across_edge (tree, edge, bool,
 854                                 VEC(tree, heap) **, tree (*) (tree));
 855
 856 /* In tree-ssa-loop-im.c  */
 857 /* The possibilities of statement movement.  */
 858
 859 enum move_pos
 860   {
 861     MOVE_IMPOSSIBLE,            /* No movement -- side effect expression.  */
 862     MOVE_PRESERVE_EXECUTION,    /* Must not cause the non-executed statement
 863                                    become executed -- memory accesses, ... */
 864     MOVE_POSSIBLE               /* Unlimited movement.  */
 865   };
 866 extern enum move_pos movement_possibility (tree);
 867
 868 /* The reasons a variable may escape a function.  */
 869 enum escape_type
 870   {
 871     NO_ESCAPE = 0, /* Doesn't escape.  */
 872     ESCAPE_STORED_IN_GLOBAL = 1 << 1,
 873     ESCAPE_TO_ASM = 1 << 2,  /* Passed by address to an assembly
 874                                 statement.  */
 875     ESCAPE_TO_CALL = 1 << 3,  /* Escapes to a function call.  */
 876     ESCAPE_BAD_CAST = 1 << 4, /* Cast from pointer to integer */
 877     ESCAPE_TO_RETURN = 1 << 5, /* Returned from function.  */
 878     ESCAPE_TO_PURE_CONST = 1 << 6, /* Escapes to a pure or constant
 879                                       function call.  */
 880     ESCAPE_IS_GLOBAL = 1 << 7,  /* Is a global variable.  */
 881     ESCAPE_IS_PARM = 1 << 8, /* Is an incoming function parameter.  */
 882     ESCAPE_UNKNOWN = 1 << 9 /* We believe it escapes for some reason
 883                                not enumerated above.  */
 884   };
 885
 886 /* In tree-flow-inline.h  */
 887 static inline bool is_call_clobbered (tree);
 888 static inline void mark_call_clobbered (tree, unsigned int);
 889 static inline void set_is_used (tree);
 890 static inline bool unmodifiable_var_p (tree);
 891
 892 /* In tree-eh.c  */
 893 extern void make_eh_edges (tree);
 894 extern bool tree_could_trap_p (tree);
 895 extern bool tree_could_throw_p (tree);
 896 extern bool tree_can_throw_internal (tree);
 897 extern bool tree_can_throw_external (tree);
 898 extern int lookup_stmt_eh_region (tree);
 899 extern void add_stmt_to_eh_region (tree, int);
 900 extern bool remove_stmt_from_eh_region (tree);
 901 extern bool maybe_clean_or_replace_eh_stmt (tree, tree);
 902
 903 /* In tree-ssa-pre.c  */
 904 void add_to_value (tree, tree);
 905 void debug_value_expressions (tree);
 906 void print_value_expressions (FILE *, tree);
 907
 908
 909 /* In tree-vn.c  */
 910 bool expressions_equal_p (tree, tree);
 911 tree get_value_handle (tree);
 912 hashval_t vn_compute (tree, hashval_t);
 913 void sort_vuses (VEC (tree, gc) *);
 914 tree vn_lookup_or_add (tree, tree);
 915 tree vn_lookup_or_add_with_vuses (tree, VEC (tree, gc) *);
 916 void vn_add (tree, tree);
 917 void vn_add_with_vuses (tree, tree, VEC (tree, gc) *);
 918 tree vn_lookup (tree, tree);
 919 tree vn_lookup_with_vuses (tree, VEC (tree, gc) *);
 920 void vn_init (void);
 921 void vn_delete (void);
 922
 923 /* In tree-ssa-sink.c  */
 924 bool is_hidden_global_store (tree);
 925
 926 /* In tree-sra.c  */
 927 void insert_edge_copies (tree, basic_block);
 928 void sra_insert_before (block_stmt_iterator *, tree);
 929 void sra_insert_after (block_stmt_iterator *, tree);
 930 void sra_init_cache (void);
 931 bool sra_type_can_be_decomposed_p (tree);
 932
 933 /* In tree-loop-linear.c  */
 934 extern void linear_transform_loops (struct loops *);
 935
 936 /* In tree-ssa-loop-ivopts.c  */
 937 bool expr_invariant_in_loop_p (struct loop *, tree);
 938 bool multiplier_allowed_in_address_p (HOST_WIDE_INT);
 939 unsigned multiply_by_cost (HOST_WIDE_INT, enum machine_mode);
 940
 941 /* In tree-ssa-threadupdate.c.  */
 942 extern bool thread_through_all_blocks (void);
 943 extern void register_jump_thread (edge, edge);
 944
 945 /* In gimplify.c  */
 946 tree force_gimple_operand (tree, tree *, bool, tree);
 947 tree force_gimple_operand_bsi (block_stmt_iterator *, tree, bool, tree);
 948
 949 /* In tree-ssa-structalias.c */
 950 bool find_what_p_points_to (tree);
 951
 952 /* In tree-ssa-live.c */
 953 extern void remove_unused_locals (void);
 954
 955 /* In tree-ssa-address.c  */
 956
 957 /* Affine combination of trees.  We keep track of at most MAX_AFF_ELTS elements
 958    to make things simpler; this is sufficient in most cases.  */
 959
 960 #define MAX_AFF_ELTS 8
 961
 962 struct affine_tree_combination
 963 {
 964   /* Type of the result of the combination.  */
 965   tree type;
 966
 967   /* Mask modulo that the operations are performed.  */
 968   unsigned HOST_WIDE_INT mask;
 969
 970   /* Constant offset.  */
 971   unsigned HOST_WIDE_INT offset;
 972
 973   /* Number of elements of the combination.  */
 974   unsigned n;
 975
 976   /* Elements and their coefficients.  */
 977   tree elts[MAX_AFF_ELTS];
 978   unsigned HOST_WIDE_INT coefs[MAX_AFF_ELTS];
 979
 980   /* Remainder of the expression.  */
 981   tree rest;
 982 };
 983
 984 /* Description of a memory address.  */
 985
 986 struct mem_address
 987 {
 988   tree symbol, base, index, step, offset;
 989 };
 990
 991 tree create_mem_ref (block_stmt_iterator *, tree,
 992                      struct affine_tree_combination *);
 993 rtx addr_for_mem_ref (struct mem_address *, bool);
 994 void get_address_description (tree, struct mem_address *);
 995 tree maybe_fold_tmr (tree);
 996
 997 /* This structure is simply used during pushing fields onto the fieldstack
 998    to track the offset of the field, since bitpos_of_field gives it relative
 999    to its immediate containing type, and we want it relative to the ultimate
1000    containing object.  */
1001
1002 struct fieldoff
1003 {
1004   tree type;
1005   tree size;
1006   tree decl;
1007   HOST_WIDE_INT offset;
1008 };
1009 typedef struct fieldoff fieldoff_s;
1010
1011 DEF_VEC_O(fieldoff_s);
1012 DEF_VEC_ALLOC_O(fieldoff_s,heap);
1013 int push_fields_onto_fieldstack (tree, VEC(fieldoff_s,heap) **,
1014                                  HOST_WIDE_INT, bool *);
1015 void sort_fieldstack (VEC(fieldoff_s,heap) *);
1016
1017 void init_alias_heapvars (void);
1018 void delete_alias_heapvars (void);
1019
1020 #include "tree-flow-inline.h"
1021
1022 void swap_tree_operands (tree, tree *, tree *);
1023
1024 extern void recalculate_used_alone (void);
1025 extern bool updating_used_alone;
1026 #endif /* _TREE_FLOW_H  */