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 struct static_var_ann_d;
  42
  43 /* Gimple dataflow datastructure. All publicly available fields shall have
  44    gimple_ accessor defined in tree-flow-inline.h, all publicly modifiable
  45    fields should have gimple_set accessor.  */
  46 struct gimple_df GTY(()) {
  47   /* Array of all variables referenced in the function.  */
  48   htab_t GTY((param_is (struct int_tree_map))) referenced_vars;
  49
  50   /* A list of all the noreturn calls passed to modify_stmt.
  51      cleanup_control_flow uses it to detect cases where a mid-block
  52      indirect call has been turned into a noreturn call.  When this
  53      happens, all the instructions after the call are no longer
  54      reachable and must be deleted as dead.  */
  55   VEC(tree,gc) *modified_noreturn_calls;
  56
  57   /* Array of all SSA_NAMEs used in the function.  */
  58   VEC(tree,gc) *ssa_names;
  59
  60   /* Artificial variable used to model the effects of function calls.  */
  61   tree global_var;
  62
  63   /* Artificial variable used to model the effects of nonlocal
  64      variables.  */
  65   tree nonlocal_all;
  66
  67   /* Call clobbered variables in the function.  If bit I is set, then
  68      REFERENCED_VARS (I) is call-clobbered.  */
  69   bitmap call_clobbered_vars;
  70
  71   /* Addressable variables in the function.  If bit I is set, then
  72      REFERENCED_VARS (I) has had its address taken.  Note that
  73      CALL_CLOBBERED_VARS and ADDRESSABLE_VARS are not related.  An
  74      addressable variable is not necessarily call-clobbered (e.g., a
  75      local addressable whose address does not escape) and not all
  76      call-clobbered variables are addressable (e.g., a local static
  77      variable).  */
  78   bitmap addressable_vars;
  79
  80   /* Free list of SSA_NAMEs.  */
  81   tree free_ssanames;
  82
  83   /* Hashtable holding definition for symbol.  If this field is not NULL, it
  84      means that the first reference to this variable in the function is a
  85      USE or a VUSE.  In those cases, the SSA renamer creates an SSA name
  86      for this variable with an empty defining statement.  */
  87   htab_t GTY((param_is (struct int_tree_map))) default_defs;
  88
  89   /* 'true' after aliases have been computed (see compute_may_aliases).  */
  90   unsigned int aliases_computed_p : 1;
  91
  92   /* True if the code is in ssa form.  */
  93   unsigned int in_ssa_p : 1;
  94
  95   struct ssa_operands ssa_operands;
  96
  97   /* Hashtable of variables annotations.  Used for static variables only;
  98      local variables have direct pointer in the tree node.  */
  99   htab_t GTY((param_is (struct static_var_ann_d))) var_anns;
 100 };
 101
 102 /* Accessors for internal use only.  Generic code should use abstraction
 103    provided by tree-flow-inline.h or specific modules.  */
 104 #define FREE_SSANAMES(fun) (fun)->gimple_df->free_ssanames
 105 #define SSANAMES(fun) (fun)->gimple_df->ssa_names
 106 #define MODIFIED_NORETURN_CALLS(fun) (fun)->gimple_df->modified_noreturn_calls
 107 #define DEFAULT_DEFS(fun) (fun)->gimple_df->default_defs
 108
 109 typedef struct
 110 {
 111   htab_t htab;
 112   PTR *slot;
 113   PTR *limit;
 114 } htab_iterator;
 115
 116 /* Iterate through the elements of hashtable HTAB, using htab_iterator ITER,
 117    storing each element in RESULT, which is of type TYPE.  */
 118 #define FOR_EACH_HTAB_ELEMENT(HTAB, RESULT, TYPE, ITER) \
 119   for (RESULT = (TYPE) first_htab_element (&(ITER), (HTAB)); \
 120         !end_htab_p (&(ITER)); \
 121         RESULT = (TYPE) next_htab_element (&(ITER)))
 122
 123 /*---------------------------------------------------------------------------
 124                       Attributes for SSA_NAMEs.
 125
 126   NOTE: These structures are stored in struct tree_ssa_name
 127   but are only used by the tree optimizers, so it makes better sense
 128   to declare them here to avoid recompiling unrelated files when
 129   making changes.
 130 ---------------------------------------------------------------------------*/
 131
 132 /* Aliasing information for SSA_NAMEs representing pointer variables.  */
 133 struct ptr_info_def GTY(())
 134 {
 135   /* Nonzero if points-to analysis couldn't determine where this pointer
 136      is pointing to.  */
 137   unsigned int pt_anything : 1;
 138
 139   /* Nonzero if the value of this pointer escapes the current function.  */
 140   unsigned int value_escapes_p : 1;
 141
 142   /* Nonzero if this pointer is dereferenced.  */
 143   unsigned int is_dereferenced : 1;
 144
 145   /* Nonzero if this pointer points to a global variable.  */
 146   unsigned int pt_global_mem : 1;
 147
 148   /* Nonzero if this pointer points to NULL.  */
 149   unsigned int pt_null : 1;
 150
 151   /* Set of variables that this pointer may point to.  */
 152   bitmap pt_vars;
 153
 154   /* If this pointer has been dereferenced, and points-to information is
 155      more precise than type-based aliasing, indirect references to this
 156      pointer will be represented by this memory tag, instead of the type
 157      tag computed by TBAA.  */
 158   tree name_mem_tag;
 159
 160   /* Mask of reasons this pointer's value escapes the function  */
 161   unsigned int escape_mask;
 162 };
 163
 164
 165 /*---------------------------------------------------------------------------
 166                    Tree annotations stored in tree_base.ann
 167 ---------------------------------------------------------------------------*/
 168 enum tree_ann_type { TREE_ANN_COMMON, VAR_ANN, FUNCTION_ANN, STMT_ANN };
 169
 170 struct tree_ann_common_d GTY(())
 171 {
 172   /* Annotation type.  */
 173   enum tree_ann_type type;
 174
 175  /* Auxiliary info specific to a pass.  At all times, this
 176     should either point to valid data or be NULL.  */
 177   PTR GTY ((skip (""))) aux;
 178
 179   /* The value handle for this expression.  Used by GVN-PRE.  */
 180   tree GTY((skip)) value_handle;
 181 };
 182
 183 /* It is advantageous to avoid things like life analysis for variables which
 184    do not need PHI nodes.  This enum describes whether or not a particular
 185    variable may need a PHI node.  */
 186
 187 enum need_phi_state {
 188   /* This is the default.  If we are still in this state after finding
 189      all the definition and use sites, then we will assume the variable
 190      needs PHI nodes.  This is probably an overly conservative assumption.  */
 191   NEED_PHI_STATE_UNKNOWN,
 192
 193   /* This state indicates that we have seen one or more sets of the
 194      variable in a single basic block and that the sets dominate all
 195      uses seen so far.  If after finding all definition and use sites
 196      we are still in this state, then the variable does not need any
 197      PHI nodes.  */
 198   NEED_PHI_STATE_NO,
 199
 200   /* This state indicates that we have either seen multiple definitions of
 201      the variable in multiple blocks, or that we encountered a use in a
 202      block that was not dominated by the block containing the set(s) of
 203      this variable.  This variable is assumed to need PHI nodes.  */
 204   NEED_PHI_STATE_MAYBE
 205 };
 206
 207 struct subvar;
 208 typedef struct subvar *subvar_t;
 209
 210 /* This structure represents a fake sub-variable for a structure field.  */
 211 struct subvar GTY(())
 212 {
 213   /* Fake variable.  */
 214   tree var;
 215
 216   /* Next subvar for this structure.  */
 217   subvar_t next;
 218 };
 219
 220 struct var_ann_d GTY(())
 221 {
 222   struct tree_ann_common_d common;
 223
 224   /* Used by the out of SSA pass to determine whether this variable has
 225      been seen yet or not.  */
 226   unsigned out_of_ssa_tag : 1;
 227
 228   /* Used when building base variable structures in a var_map.  */
 229   unsigned base_var_processed : 1;
 230
 231   /* Nonzero if this variable was used after SSA optimizations were
 232      applied.  We set this when translating out of SSA form.  */
 233   unsigned used : 1;
 234
 235   /* This field indicates whether or not the variable may need PHI nodes.
 236      See the enum's definition for more detailed information about the
 237      states.  */
 238   ENUM_BITFIELD (need_phi_state) need_phi_state : 2;
 239
 240   /* Used during operand processing to determine if this variable is already
 241      in the VUSE list.  */
 242   unsigned in_vuse_list : 1;
 243
 244   /* Used during operand processing to determine if this variable is already
 245      in the VDEF list.  */
 246   unsigned in_vdef_list : 1;
 247
 248   /* True for HEAP and PARM_NOALIAS artificial variables.  */
 249   unsigned is_heapvar : 1;
 250
 251   /* True if the variable is call clobbered.  */
 252   unsigned int call_clobbered : 1;
 253
 254   /* Memory partition tag assigned to this symbol.  */
 255   tree mpt;
 256
 257   /* If this variable is a pointer P that has been dereferenced, this
 258      field is an artificial variable that represents the memory
 259      location *P.  Every other pointer Q that is type-compatible with
 260      P will also have the same memory tag.  If the variable is not a
 261      pointer or if it is never dereferenced, this must be NULL.
 262      FIXME, do we really need this here?  How much slower would it be
 263      to convert to hash table?  */
 264   tree symbol_mem_tag;
 265
 266   /* Used when going out of SSA form to indicate which partition this
 267      variable represents storage for.  */
 268   unsigned partition;
 269
 270   /* Used by var_map for the base index of ssa base variables.  */
 271   unsigned base_index;
 272
 273   /* During into-ssa and the dominator optimizer, this field holds the
 274      current version of this variable (an SSA_NAME).  */
 275   tree current_def;
 276
 277   /* If this variable is a structure, this fields holds a list of
 278      symbols representing each of the fields of the structure.  */
 279   subvar_t subvars;
 280
 281   /* Mask of values saying the reasons why this variable has escaped
 282      the function.  */
 283   unsigned int escape_mask;
 284 };
 285
 286 /* Container for variable annotation used by hashtable for annotations for
 287    static variables.  */
 288 struct static_var_ann_d GTY(())
 289 {
 290   struct var_ann_d ann;
 291   unsigned int uid;
 292 };
 293
 294 struct function_ann_d GTY(())
 295 {
 296   struct tree_ann_common_d common;
 297
 298   /* Pointer to the structure that contains the sets of global
 299      variables modified by function calls.  This field is only used
 300      for FUNCTION_DECLs.  */
 301   ipa_reference_vars_info_t GTY ((skip)) reference_vars_info;
 302 };
 303
 304 typedef struct immediate_use_iterator_d
 305 {
 306   /* This is the current use the iterator is processing.  */
 307   ssa_use_operand_t *imm_use;
 308   /* This marks the last use in the list (use node from SSA_NAME)  */
 309   ssa_use_operand_t *end_p;
 310   /* This node is inserted and used to mark the end of the uses for a stmt.  */
 311   ssa_use_operand_t iter_node;
 312   /* This is the next ssa_name to visit.  IMM_USE may get removed before
 313      the next one is traversed to, so it must be cached early.  */
 314   ssa_use_operand_t *next_imm_name;
 315 } imm_use_iterator;
 316
 317
 318 /* Use this iterator when simply looking at stmts.  Adding, deleting or
 319    modifying stmts will cause this iterator to malfunction.  */
 320
 321 #define FOR_EACH_IMM_USE_FAST(DEST, ITER, SSAVAR)                       \
 322   for ((DEST) = first_readonly_imm_use (&(ITER), (SSAVAR));     \
 323        !end_readonly_imm_use_p (&(ITER));                       \
 324        (DEST) = next_readonly_imm_use (&(ITER)))
 325
 326 /* Use this iterator to visit each stmt which has a use of SSAVAR.  */
 327
 328 #define FOR_EACH_IMM_USE_STMT(STMT, ITER, SSAVAR)               \
 329   for ((STMT) = first_imm_use_stmt (&(ITER), (SSAVAR));         \
 330        !end_imm_use_stmt_p (&(ITER));                           \
 331        (STMT) = next_imm_use_stmt (&(ITER)))
 332
 333 /* Use this to terminate the FOR_EACH_IMM_USE_STMT loop early.  Failure to
 334    do so will result in leaving a iterator marker node in the immediate
 335    use list, and nothing good will come from that.   */
 336 #define BREAK_FROM_IMM_USE_STMT(ITER)                           \
 337    {                                                            \
 338      end_imm_use_stmt_traverse (&(ITER));                       \
 339      break;                                                     \
 340    }
 341
 342
 343 /* Use this iterator in combination with FOR_EACH_IMM_USE_STMT to
 344    get access to each occurrence of ssavar on the stmt returned by
 345    that iterator..  for instance:
 346
 347      FOR_EACH_IMM_USE_STMT (stmt, iter, var)
 348        {
 349          FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
 350            {
 351              SET_USE (use_p) = blah;
 352            }
 353          update_stmt (stmt);
 354        }                                                         */
 355
 356 #define FOR_EACH_IMM_USE_ON_STMT(DEST, ITER)                    \
 357   for ((DEST) = first_imm_use_on_stmt (&(ITER));                \
 358        !end_imm_use_on_stmt_p (&(ITER));                        \
 359        (DEST) = next_imm_use_on_stmt (&(ITER)))
 360
 361
 362
 363 struct stmt_ann_d GTY(())
 364 {
 365   struct tree_ann_common_d common;
 366
 367   /* Basic block that contains this statement.  */
 368   basic_block bb;
 369
 370   /* Operand cache for stmt.  */
 371   struct stmt_operands_d GTY ((skip (""))) operands;
 372
 373   /* Set of variables that have had their address taken in the statement.  */
 374   bitmap addresses_taken;
 375
 376   /* Unique identifier for this statement.  These ID's are to be created
 377      by each pass on an as-needed basis in any order convenient for the
 378      pass which needs statement UIDs.  */
 379   unsigned int uid;
 380
 381   /* Nonzero if the statement references memory (at least one of its
 382      expressions contains a non-register operand).  */
 383   unsigned references_memory : 1;
 384
 385   /* Nonzero if the statement has been modified (meaning that the operands
 386      need to be scanned again).  */
 387   unsigned modified : 1;
 388
 389   /* Nonzero if the statement makes references to volatile storage.  */
 390   unsigned has_volatile_ops : 1;
 391
 392   /* Nonzero if the statement makes a function call that may clobber global
 393      and local addressable variables.  */
 394   unsigned makes_clobbering_call : 1;
 395 };
 396
 397 union tree_ann_d GTY((desc ("ann_type ((tree_ann_t)&%h)")))
 398 {
 399   struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
 400   struct var_ann_d GTY((tag ("VAR_ANN"))) vdecl;
 401   struct function_ann_d GTY((tag ("FUNCTION_ANN"))) fdecl;
 402   struct stmt_ann_d GTY((tag ("STMT_ANN"))) stmt;
 403 };
 404
 405 typedef union tree_ann_d *tree_ann_t;
 406 typedef struct var_ann_d *var_ann_t;
 407 typedef struct function_ann_d *function_ann_t;
 408 typedef struct stmt_ann_d *stmt_ann_t;
 409 typedef struct tree_ann_common_d *tree_ann_common_t;
 410
 411 static inline tree_ann_common_t tree_common_ann (tree);
 412 static inline tree_ann_common_t get_tree_common_ann (tree);
 413 static inline var_ann_t var_ann (tree);
 414 static inline var_ann_t get_var_ann (tree);
 415 static inline function_ann_t function_ann (tree);
 416 static inline function_ann_t get_function_ann (tree);
 417 static inline stmt_ann_t stmt_ann (tree);
 418 static inline bool has_stmt_ann (tree);
 419 static inline stmt_ann_t get_stmt_ann (tree);
 420 static inline enum tree_ann_type ann_type (tree_ann_t);
 421 static inline basic_block bb_for_stmt (tree);
 422 extern void set_bb_for_stmt (tree, basic_block);
 423 static inline bool noreturn_call_p (tree);
 424 static inline void update_stmt (tree);
 425 static inline bool stmt_modified_p (tree);
 426 static inline bitmap may_aliases (tree);
 427 static inline int get_lineno (tree);
 428 static inline const char *get_filename (tree);
 429 static inline bool is_exec_stmt (tree);
 430 static inline bool is_label_stmt (tree);
 431 static inline bitmap addresses_taken (tree);
 432
 433 /*---------------------------------------------------------------------------
 434                   Structure representing predictions in tree level.
 435 ---------------------------------------------------------------------------*/
 436 struct edge_prediction GTY((chain_next ("%h.ep_next")))
 437 {
 438   struct edge_prediction *ep_next;
 439   edge ep_edge;
 440   enum br_predictor ep_predictor;
 441   int ep_probability;
 442 };
 443
 444 /* Accessors for basic block annotations.  */
 445 static inline tree phi_nodes (basic_block);
 446 static inline void set_phi_nodes (basic_block, tree);
 447
 448 /*---------------------------------------------------------------------------
 449                               Global declarations
 450 ---------------------------------------------------------------------------*/
 451 struct int_tree_map GTY(())
 452 {
 453
 454   unsigned int uid;
 455   tree to;
 456 };
 457
 458 extern unsigned int int_tree_map_hash (const void *);
 459 extern int int_tree_map_eq (const void *, const void *);
 460
 461 typedef struct
 462 {
 463   htab_iterator hti;
 464 } referenced_var_iterator;
 465
 466
 467 /* This macro loops over all the referenced vars, one at a time, putting the
 468    current var in VAR.  Note:  You are not allowed to add referenced variables
 469    to the hashtable while using this macro.  Doing so may cause it to behave
 470    erratically.  */
 471
 472 #define FOR_EACH_REFERENCED_VAR(VAR, ITER) \
 473   for ((VAR) = first_referenced_var (&(ITER)); \
 474        !end_referenced_vars_p (&(ITER)); \
 475        (VAR) = next_referenced_var (&(ITER)))
 476
 477
 478 typedef struct
 479 {
 480   int i;
 481 } safe_referenced_var_iterator;
 482
 483 /* This macro loops over all the referenced vars, one at a time, putting the
 484    current var in VAR.  You are allowed to add referenced variables during the
 485    execution of this macro, however, the macro will not iterate over them.  It
 486    requires a temporary vector of trees, VEC, whose lifetime is controlled by
 487    the caller.  The purpose of the vector is to temporarily store the
 488    referenced_variables hashtable so that adding referenced variables does not
 489    affect the hashtable.  */
 490
 491 #define FOR_EACH_REFERENCED_VAR_SAFE(VAR, VEC, ITER) \
 492   for ((ITER).i = 0, fill_referenced_var_vec (&(VEC)); \
 493        VEC_iterate (tree, (VEC), (ITER).i, (VAR)); \
 494        (ITER).i++)
 495
 496 extern tree referenced_var_lookup (unsigned int);
 497 extern bool referenced_var_check_and_insert (tree);
 498 #define num_referenced_vars htab_elements (gimple_referenced_vars (cfun))
 499 #define referenced_var(i) referenced_var_lookup (i)
 500
 501 #define num_ssa_names (VEC_length (tree, cfun->gimple_df->ssa_names))
 502 #define ssa_name(i) (VEC_index (tree, cfun->gimple_df->ssa_names, (i)))
 503
 504 /* Macros for showing usage statistics.  */
 505 #define SCALE(x) ((unsigned long) ((x) < 1024*10        \
 506                   ? (x)                                 \
 507                   : ((x) < 1024*1024*10                 \
 508                      ? (x) / 1024                       \
 509                      : (x) / (1024*1024))))
 510
 511 #define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
 512
 513 #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
 514
 515 /*---------------------------------------------------------------------------
 516                               Block iterators
 517 ---------------------------------------------------------------------------*/
 518
 519 typedef struct {
 520   tree_stmt_iterator tsi;
 521   basic_block bb;
 522 } block_stmt_iterator;
 523
 524 static inline block_stmt_iterator bsi_start (basic_block);
 525 static inline block_stmt_iterator bsi_last (basic_block);
 526 static inline block_stmt_iterator bsi_after_labels (basic_block);
 527 block_stmt_iterator bsi_for_stmt (tree);
 528 static inline bool bsi_end_p (block_stmt_iterator);
 529 static inline void bsi_next (block_stmt_iterator *);
 530 static inline void bsi_prev (block_stmt_iterator *);
 531 static inline tree bsi_stmt (block_stmt_iterator);
 532 static inline tree * bsi_stmt_ptr (block_stmt_iterator);
 533
 534 extern void bsi_remove (block_stmt_iterator *, bool);
 535 extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
 536 extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
 537 extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
 538
 539 enum bsi_iterator_update
 540 {
 541   /* Note that these are intentionally in the same order as TSI_FOO.  They
 542      mean exactly the same as their TSI_* counterparts.  */
 543   BSI_NEW_STMT,
 544   BSI_SAME_STMT,
 545   BSI_CHAIN_START,
 546   BSI_CHAIN_END,
 547   BSI_CONTINUE_LINKING
 548 };
 549
 550 extern void bsi_insert_before (block_stmt_iterator *, tree,
 551                                enum bsi_iterator_update);
 552 extern void bsi_insert_after (block_stmt_iterator *, tree,
 553                               enum bsi_iterator_update);
 554
 555 extern void bsi_replace (const block_stmt_iterator *, tree, bool);
 556
 557 /*---------------------------------------------------------------------------
 558                               OpenMP Region Tree
 559 ---------------------------------------------------------------------------*/
 560
 561 /* Parallel region information.  Every parallel and workshare
 562    directive is enclosed between two markers, the OMP_* directive
 563    and a corresponding OMP_RETURN statement.  */
 564
 565 struct omp_region
 566 {
 567   /* The enclosing region.  */
 568   struct omp_region *outer;
 569
 570   /* First child region.  */
 571   struct omp_region *inner;
 572
 573   /* Next peer region.  */
 574   struct omp_region *next;
 575
 576   /* Block containing the omp directive as its last stmt.  */
 577   basic_block entry;
 578
 579   /* Block containing the OMP_RETURN as its last stmt.  */
 580   basic_block exit;
 581
 582   /* Block containing the OMP_CONTINUE as its last stmt.  */
 583   basic_block cont;
 584
 585   /* If this is a combined parallel+workshare region, this is a list
 586      of additional arguments needed by the combined parallel+workshare
 587      library call.  */
 588   tree ws_args;
 589
 590   /* The code for the omp directive of this region.  */
 591   enum tree_code type;
 592
 593   /* Schedule kind, only used for OMP_FOR type regions.  */
 594   enum omp_clause_schedule_kind sched_kind;
 595
 596   /* True if this is a combined parallel+workshare region.  */
 597   bool is_combined_parallel;
 598 };
 599
 600 extern struct omp_region *root_omp_region;
 601 extern struct omp_region *new_omp_region (basic_block, enum tree_code,
 602                                           struct omp_region *);
 603 extern void free_omp_regions (void);
 604
 605 /*---------------------------------------------------------------------------
 606                               Function prototypes
 607 ---------------------------------------------------------------------------*/
 608 /* In tree-cfg.c  */
 609
 610 /* Location to track pending stmt for edge insertion.  */
 611 #define PENDING_STMT(e) ((e)->insns.t)
 612
 613 extern void delete_tree_cfg_annotations (void);
 614 extern void disband_implicit_edges (void);
 615 extern bool stmt_ends_bb_p (tree);
 616 extern bool is_ctrl_stmt (tree);
 617 extern bool is_ctrl_altering_stmt (tree);
 618 extern bool computed_goto_p (tree);
 619 extern bool simple_goto_p (tree);
 620 extern bool tree_can_make_abnormal_goto (tree);
 621 extern basic_block single_noncomplex_succ (basic_block bb);
 622 extern void tree_dump_bb (basic_block, FILE *, int);
 623 extern void debug_tree_bb (basic_block);
 624 extern basic_block debug_tree_bb_n (int);
 625 extern void dump_tree_cfg (FILE *, int);
 626 extern void debug_tree_cfg (int);
 627 extern void dump_cfg_stats (FILE *);
 628 extern void debug_cfg_stats (void);
 629 extern void debug_loop_ir (void);
 630 extern void print_loop_ir (FILE *);
 631 extern void cleanup_dead_labels (void);
 632 extern void group_case_labels (void);
 633 extern tree first_stmt (basic_block);
 634 extern tree last_stmt (basic_block);
 635 extern tree last_and_only_stmt (basic_block);
 636 extern edge find_taken_edge (basic_block, tree);
 637 extern basic_block label_to_block_fn (struct function *, tree);
 638 #define label_to_block(t) (label_to_block_fn (cfun, t))
 639 extern void bsi_insert_on_edge (edge, tree);
 640 extern basic_block bsi_insert_on_edge_immediate (edge, tree);
 641 extern void bsi_commit_one_edge_insert (edge, basic_block *);
 642 extern void bsi_commit_edge_inserts (void);
 643 extern void notice_special_calls (tree);
 644 extern void clear_special_calls (void);
 645 extern void verify_stmts (void);
 646 extern tree tree_block_label (basic_block);
 647 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
 648 extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
 649                                         basic_block *);
 650 extern void add_phi_args_after_copy_bb (basic_block);
 651 extern void add_phi_args_after_copy (basic_block *, unsigned);
 652 extern bool tree_purge_dead_abnormal_call_edges (basic_block);
 653 extern bool tree_purge_dead_eh_edges (basic_block);
 654 extern bool tree_purge_all_dead_eh_edges (bitmap);
 655 extern tree gimplify_val (block_stmt_iterator *, tree, tree);
 656 extern tree gimplify_build1 (block_stmt_iterator *, enum tree_code,
 657                              tree, tree);
 658 extern tree gimplify_build2 (block_stmt_iterator *, enum tree_code,
 659                              tree, tree, tree);
 660 extern tree gimplify_build3 (block_stmt_iterator *, enum tree_code,
 661                              tree, tree, tree, tree);
 662 extern void init_empty_tree_cfg (void);
 663 extern void fold_cond_expr_cond (void);
 664 extern void make_abnormal_goto_edges (basic_block, bool);
 665 extern void replace_uses_by (tree, tree);
 666 extern void start_recording_case_labels (void);
 667 extern void end_recording_case_labels (void);
 668 extern basic_block move_sese_region_to_fn (struct function *, basic_block,
 669                                            basic_block);
 670
 671 /* In tree-cfgcleanup.c  */
 672 extern bool cleanup_tree_cfg (void);
 673 extern bool cleanup_tree_cfg_loop (void);
 674
 675 /* In tree-pretty-print.c.  */
 676 extern void dump_generic_bb (FILE *, basic_block, int, int);
 677
 678 /* In tree-dfa.c  */
 679 extern var_ann_t create_var_ann (tree);
 680 extern function_ann_t create_function_ann (tree);
 681 extern stmt_ann_t create_stmt_ann (tree);
 682 extern tree_ann_common_t create_tree_common_ann (tree);
 683 extern void dump_dfa_stats (FILE *);
 684 extern void debug_dfa_stats (void);
 685 extern void debug_referenced_vars (void);
 686 extern void dump_referenced_vars (FILE *);
 687 extern void dump_variable (FILE *, tree);
 688 extern void debug_variable (tree);
 689 extern void dump_subvars_for (FILE *, tree);
 690 extern void debug_subvars_for (tree);
 691 extern tree get_virtual_var (tree);
 692 extern void add_referenced_var (tree);
 693 extern void remove_referenced_var (tree);
 694 extern void mark_symbols_for_renaming (tree);
 695 extern void find_new_referenced_vars (tree *);
 696
 697 extern tree make_rename_temp (tree, const char *);
 698 extern void set_default_def (tree, tree);
 699 extern tree gimple_default_def (struct function *, tree);
 700
 701 /* In tree-phinodes.c  */
 702 extern void reserve_phi_args_for_new_edge (basic_block);
 703 extern tree create_phi_node (tree, basic_block);
 704 extern void add_phi_arg (tree, tree, edge);
 705 extern void remove_phi_args (edge);
 706 extern void remove_phi_node (tree, tree, bool);
 707 extern tree phi_reverse (tree);
 708
 709 /* In gimple-low.c  */
 710 extern void record_vars_into (tree, tree);
 711 extern void record_vars (tree);
 712 extern bool block_may_fallthru (tree);
 713
 714 /* In tree-ssa-alias.c  */
 715 extern void dump_may_aliases_for (FILE *, tree);
 716 extern void debug_may_aliases_for (tree);
 717 extern void dump_alias_info (FILE *);
 718 extern void debug_alias_info (void);
 719 extern void dump_points_to_info (FILE *);
 720 extern void debug_points_to_info (void);
 721 extern void dump_points_to_info_for (FILE *, tree);
 722 extern void debug_points_to_info_for (tree);
 723 extern bool may_be_aliased (tree);
 724 extern bool is_aliased_with (tree, tree);
 725 extern struct ptr_info_def *get_ptr_info (tree);
 726 extern void new_type_alias (tree, tree, tree);
 727 extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *, bool *);
 728 static inline subvar_t get_subvars_for_var (tree);
 729 static inline tree get_subvar_at (tree, unsigned HOST_WIDE_INT);
 730 static inline bool ref_contains_array_ref (tree);
 731 static inline bool array_ref_contains_indirect_ref (tree);
 732 extern tree get_ref_base_and_extent (tree, HOST_WIDE_INT *,
 733                                      HOST_WIDE_INT *, HOST_WIDE_INT *);
 734 static inline bool var_can_have_subvars (tree);
 735 static inline bool overlap_subvar (unsigned HOST_WIDE_INT,
 736                                    unsigned HOST_WIDE_INT,
 737                                    tree, bool *);
 738 extern tree create_tag_raw (enum tree_code, tree, const char *);
 739
 740 /* Call-back function for walk_use_def_chains().  At each reaching
 741    definition, a function with this prototype is called.  */
 742 typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
 743
 744
 745 /* In tree-ssa.c  */
 746 extern void init_tree_ssa (void);
 747 extern edge ssa_redirect_edge (edge, basic_block);
 748 extern void flush_pending_stmts (edge);
 749 extern bool tree_ssa_useless_type_conversion (tree);
 750 extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
 751 extern void verify_ssa (bool);
 752 extern void delete_tree_ssa (void);
 753 extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *, bool);
 754 extern bool stmt_references_memory_p (tree);
 755
 756 /* In tree-into-ssa.c  */
 757 void update_ssa (unsigned);
 758 void delete_update_ssa (void);
 759 void register_new_name_mapping (tree, tree);
 760 tree create_new_def_for (tree, tree, def_operand_p);
 761 bool need_ssa_update_p (void);
 762 bool name_mappings_registered_p (void);
 763 bool name_registered_for_update_p (tree);
 764 bitmap ssa_names_to_replace (void);
 765 void release_ssa_name_after_update_ssa (tree);
 766 void compute_global_livein (bitmap, bitmap);
 767 tree duplicate_ssa_name (tree, tree);
 768 void mark_sym_for_renaming (tree);
 769 void mark_set_for_renaming (bitmap);
 770 tree get_current_def (tree);
 771 void set_current_def (tree, tree);
 772
 773 /* In tree-ssa-ccp.c  */
 774 bool fold_stmt (tree *);
 775 bool fold_stmt_inplace (tree);
 776 tree widen_bitfield (tree, tree, tree);
 777
 778 /* In tree-vrp.c  */
 779 tree vrp_evaluate_conditional (tree, bool);
 780 void simplify_stmt_using_ranges (tree);
 781
 782 /* In tree-ssa-dom.c  */
 783 extern void dump_dominator_optimization_stats (FILE *);
 784 extern void debug_dominator_optimization_stats (void);
 785 int loop_depth_of_name (tree);
 786
 787 /* In tree-ssa-copy.c  */
 788 extern void merge_alias_info (tree, tree);
 789 extern void propagate_value (use_operand_p, tree);
 790 extern void propagate_tree_value (tree *, tree);
 791 extern void replace_exp (use_operand_p, tree);
 792 extern bool may_propagate_copy (tree, tree);
 793 extern bool may_propagate_copy_into_asm (tree);
 794
 795 /* Affine iv.  */
 796
 797 typedef struct
 798 {
 799   /* Iv = BASE + STEP * i.  */
 800   tree base, step;
 801
 802   /* True if this iv does not overflow.  */
 803   bool no_overflow;
 804 } affine_iv;
 805
 806 /* Description of number of iterations of a loop.  All the expressions inside
 807    the structure can be evaluated at the end of the loop's preheader
 808    (and due to ssa form, also anywhere inside the body of the loop).  */
 809
 810 struct tree_niter_desc
 811 {
 812   tree assumptions;     /* The boolean expression.  If this expression evaluates
 813                            to false, then the other fields in this structure
 814                            should not be used; there is no guarantee that they
 815                            will be correct.  */
 816   tree may_be_zero;     /* The boolean expression.  If it evaluates to true,
 817                            the loop will exit in the first iteration (i.e.
 818                            its latch will not be executed), even if the niter
 819                            field says otherwise.  */
 820   tree niter;           /* The expression giving the number of iterations of
 821                            a loop (provided that assumptions == true and
 822                            may_be_zero == false), more precisely the number
 823                            of executions of the latch of the loop.  */
 824   tree additional_info; /* The boolean expression.  Sometimes we use additional
 825                            knowledge to simplify the other expressions
 826                            contained in this structure (for example the
 827                            knowledge about value ranges of operands on entry to
 828                            the loop).  If this is a case, conjunction of such
 829                            condition is stored in this field, so that we do not
 830                            lose the information: for example if may_be_zero
 831                            is (n <= 0) and niter is (unsigned) n, we know
 832                            that the number of iterations is at most
 833                            MAX_SIGNED_INT.  However if the (n <= 0) assumption
 834                            is eliminated (by looking at the guard on entry of
 835                            the loop), then the information would be lost.  */
 836
 837   /* The simplified shape of the exit condition.  The loop exits if
 838      CONTROL CMP BOUND is false, where CMP is one of NE_EXPR,
 839      LT_EXPR, or GT_EXPR, and step of CONTROL is positive if CMP is
 840      LE_EXPR and negative if CMP is GE_EXPR.  This information is used
 841      by loop unrolling.  */
 842   affine_iv control;
 843   tree bound;
 844   enum tree_code cmp;
 845 };
 846
 847 /* In tree-vectorizer.c */
 848 unsigned vectorize_loops (void);
 849 extern bool vect_can_force_dr_alignment_p (tree, unsigned int);
 850 extern tree get_vectype_for_scalar_type (tree);
 851
 852 /* In tree-ssa-phiopt.c */
 853 bool empty_block_p (basic_block);
 854
 855 /* In tree-ssa-loop*.c  */
 856
 857 void tree_ssa_lim (void);
 858 unsigned int tree_ssa_unswitch_loops (void);
 859 unsigned int canonicalize_induction_variables (void);
 860 unsigned int tree_unroll_loops_completely (bool);
 861 unsigned int tree_ssa_prefetch_arrays (void);
 862 unsigned int remove_empty_loops (void);
 863 void tree_ssa_iv_optimize (void);
 864
 865 bool number_of_iterations_exit (struct loop *, edge,
 866                                 struct tree_niter_desc *niter, bool);
 867 tree find_loop_niter (struct loop *, edge *);
 868 tree loop_niter_by_eval (struct loop *, edge);
 869 tree find_loop_niter_by_eval (struct loop *, edge *);
 870 void estimate_numbers_of_iterations (void);
 871 bool scev_probably_wraps_p (tree, tree, tree, struct loop *, bool);
 872 bool convert_affine_scev (struct loop *, tree, tree *, tree *, tree, bool);
 873
 874 bool nowrap_type_p (tree);
 875 enum ev_direction {EV_DIR_GROWS, EV_DIR_DECREASES, EV_DIR_UNKNOWN};
 876 enum ev_direction scev_direction (tree);
 877
 878 void free_numbers_of_iterations_estimates (void);
 879 void free_numbers_of_iterations_estimates_loop (struct loop *);
 880 void rewrite_into_loop_closed_ssa (bitmap, unsigned);
 881 void verify_loop_closed_ssa (void);
 882 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
 883 void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
 884                 tree *, tree *);
 885 void split_loop_exit_edge (edge);
 886 unsigned force_expr_to_var_cost (tree);
 887 void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
 888                                      bool *);
 889 basic_block ip_end_pos (struct loop *);
 890 basic_block ip_normal_pos (struct loop *);
 891 bool tree_duplicate_loop_to_header_edge (struct loop *, edge,
 892                                          unsigned int, sbitmap,
 893                                          edge, VEC (edge, heap) **,
 894                                          int);
 895 struct loop *tree_ssa_loop_version (struct loop *, tree,
 896                                     basic_block *);
 897 tree expand_simple_operations (tree);
 898 void substitute_in_loop_info (struct loop *, tree, tree);
 899 edge single_dom_exit (struct loop *);
 900 bool can_unroll_loop_p (struct loop *loop, unsigned factor,
 901                         struct tree_niter_desc *niter);
 902 void tree_unroll_loop (struct loop *, unsigned,
 903                        edge, struct tree_niter_desc *);
 904 typedef void (*transform_callback)(struct loop *, void *);
 905 void tree_transform_and_unroll_loop (struct loop *, unsigned,
 906                                      edge, struct tree_niter_desc *,
 907                                      transform_callback, void *);
 908 bool contains_abnormal_ssa_name_p (tree);
 909
 910 /* In tree-ssa-threadedge.c */
 911 extern bool potentially_threadable_block (basic_block);
 912 extern void thread_across_edge (tree, edge, bool,
 913                                 VEC(tree, heap) **, tree (*) (tree));
 914
 915 /* In tree-ssa-loop-im.c  */
 916 /* The possibilities of statement movement.  */
 917
 918 enum move_pos
 919   {
 920     MOVE_IMPOSSIBLE,            /* No movement -- side effect expression.  */
 921     MOVE_PRESERVE_EXECUTION,    /* Must not cause the non-executed statement
 922                                    become executed -- memory accesses, ... */
 923     MOVE_POSSIBLE               /* Unlimited movement.  */
 924   };
 925 extern enum move_pos movement_possibility (tree);
 926
 927 /* The reasons a variable may escape a function.  */
 928 enum escape_type
 929 {
 930   NO_ESCAPE = 0,                        /* Doesn't escape.  */
 931   ESCAPE_STORED_IN_GLOBAL = 1 << 1,
 932   ESCAPE_TO_ASM = 1 << 2,               /* Passed by address to an assembly
 933                                            statement.  */
 934   ESCAPE_TO_CALL = 1 << 3,              /* Escapes to a function call.  */
 935   ESCAPE_BAD_CAST = 1 << 4,             /* Cast from pointer to integer */
 936   ESCAPE_TO_RETURN = 1 << 5,            /* Returned from function.  */
 937   ESCAPE_TO_PURE_CONST = 1 << 6,        /* Escapes to a pure or constant
 938                                            function call.  */
 939   ESCAPE_IS_GLOBAL = 1 << 7,            /* Is a global variable.  */
 940   ESCAPE_IS_PARM = 1 << 8,              /* Is an incoming function argument.  */
 941   ESCAPE_UNKNOWN = 1 << 9               /* We believe it escapes for
 942                                            some reason not enumerated
 943                                            above.  */
 944 };
 945
 946 /* In tree-flow-inline.h  */
 947 static inline bool is_call_clobbered (tree);
 948 static inline void mark_call_clobbered (tree, unsigned int);
 949 static inline void set_is_used (tree);
 950 static inline bool unmodifiable_var_p (tree);
 951
 952 /* In tree-eh.c  */
 953 extern void make_eh_edges (tree);
 954 extern bool tree_could_trap_p (tree);
 955 extern bool tree_could_throw_p (tree);
 956 extern bool tree_can_throw_internal (tree);
 957 extern bool tree_can_throw_external (tree);
 958 extern int lookup_stmt_eh_region (tree);
 959 extern void add_stmt_to_eh_region (tree, int);
 960 extern bool remove_stmt_from_eh_region (tree);
 961 extern bool maybe_clean_or_replace_eh_stmt (tree, tree);
 962
 963 /* In tree-ssa-pre.c  */
 964 void add_to_value (tree, tree);
 965 void debug_value_expressions (tree);
 966 void print_value_expressions (FILE *, tree);
 967
 968
 969 /* In tree-vn.c  */
 970 bool expressions_equal_p (tree, tree);
 971 static inline tree get_value_handle (tree);
 972 hashval_t vn_compute (tree, hashval_t);
 973 void sort_vuses (VEC (tree, gc) *);
 974 tree vn_lookup_or_add (tree, tree);
 975 tree vn_lookup_or_add_with_vuses (tree, VEC (tree, gc) *);
 976 void vn_add (tree, tree);
 977 void vn_add_with_vuses (tree, tree, VEC (tree, gc) *);
 978 tree vn_lookup (tree, tree);
 979 tree vn_lookup_with_vuses (tree, VEC (tree, gc) *);
 980 void vn_init (void);
 981 void vn_delete (void);
 982
 983 /* In tree-ssa-sink.c  */
 984 bool is_hidden_global_store (tree);
 985
 986 /* In tree-sra.c  */
 987 void insert_edge_copies (tree, basic_block);
 988 void sra_insert_before (block_stmt_iterator *, tree);
 989 void sra_insert_after (block_stmt_iterator *, tree);
 990 void sra_init_cache (void);
 991 bool sra_type_can_be_decomposed_p (tree);
 992
 993 /* In tree-loop-linear.c  */
 994 extern void linear_transform_loops (void);
 995
 996 /* In tree-ssa-loop-ivopts.c  */
 997 bool expr_invariant_in_loop_p (struct loop *, tree);
 998 bool multiplier_allowed_in_address_p (HOST_WIDE_INT, enum machine_mode);
 999 unsigned multiply_by_cost (HOST_WIDE_INT, enum machine_mode);
1000
1001 /* In tree-ssa-threadupdate.c.  */
1002 extern bool thread_through_all_blocks (void);
1003 extern void register_jump_thread (edge, edge);
1004
1005 /* In gimplify.c  */
1006 tree force_gimple_operand (tree, tree *, bool, tree);
1007 tree force_gimple_operand_bsi (block_stmt_iterator *, tree, bool, tree);
1008
1009 /* In tree-ssa-structalias.c */
1010 bool find_what_p_points_to (tree);
1011
1012 /* In tree-ssa-live.c */
1013 extern void remove_unused_locals (void);
1014
1015 /* In tree-ssa-address.c  */
1016
1017 /* Description of a memory address.  */
1018
1019 struct mem_address
1020 {
1021   tree symbol, base, index, step, offset;
1022 };
1023
1024 struct affine_tree_combination;
1025 tree create_mem_ref (block_stmt_iterator *, tree,
1026                      struct affine_tree_combination *);
1027 rtx addr_for_mem_ref (struct mem_address *, bool);
1028 void get_address_description (tree, struct mem_address *);
1029 tree maybe_fold_tmr (tree);
1030
1031 /* This structure is simply used during pushing fields onto the fieldstack
1032    to track the offset of the field, since bitpos_of_field gives it relative
1033    to its immediate containing type, and we want it relative to the ultimate
1034    containing object.  */
1035
1036 struct fieldoff
1037 {
1038   tree type;
1039   tree size;
1040   tree decl;
1041   HOST_WIDE_INT offset;
1042 };
1043 typedef struct fieldoff fieldoff_s;
1044
1045 DEF_VEC_O(fieldoff_s);
1046 DEF_VEC_ALLOC_O(fieldoff_s,heap);
1047 int push_fields_onto_fieldstack (tree, VEC(fieldoff_s,heap) **,
1048                                  HOST_WIDE_INT, bool *);
1049 void sort_fieldstack (VEC(fieldoff_s,heap) *);
1050
1051 void init_alias_heapvars (void);
1052 void delete_alias_heapvars (void);
1053 unsigned int execute_fixup_cfg (void);
1054
1055 #include "tree-flow-inline.h"
1056
1057 void swap_tree_operands (tree, tree *, tree *);
1058
1059 int least_common_multiple (int, int);
1060
1061 #endif /* _TREE_FLOW_H  */