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 /* Gimple dataflow datastructure. All publically available fields shall have
  43    gimple_ accessor defined in tree-flow-inline.h, all publically modifiable
  44    fields should have gimple_set accessor.  */
  45 struct gimple_df GTY(()) {
  46   /* Array of all variables referenced in the function.  */
  47   htab_t GTY((param_is (struct int_tree_map))) referenced_vars;
  48   /* A list of all the noreturn calls passed to modify_stmt.
  49      cleanup_control_flow uses it to detect cases where a mid-block
  50      indirect call has been turned into a noreturn call.  When this
  51      happens, all the instructions after the call are no longer
  52      reachable and must be deleted as dead.  */
  53   VEC(tree,gc) *modified_noreturn_calls;
  54   /* Array of all SSA_NAMEs used in the function.  */
  55   VEC(tree,gc) *ssa_names;
  56
  57   /* Artificial variable used to model the effects of function calls.  */
  58   tree global_var;
  59
  60   /* Artificial variable used to model the effects of nonlocal
  61      variables.  */
  62   tree nonlocal_all;
  63
  64   /* Call clobbered variables in the function.  If bit I is set, then
  65      REFERENCED_VARS (I) is call-clobbered.  */
  66   bitmap call_clobbered_vars;
  67
  68   /* Addressable variables in the function.  If bit I is set, then
  69      REFERENCED_VARS (I) has had its address taken.  Note that
  70      CALL_CLOBBERED_VARS and ADDRESSABLE_VARS are not related.  An
  71      addressable variable is not necessarily call-clobbered (e.g., a
  72      local addressable whose address does not escape) and not all
  73      call-clobbered variables are addressable (e.g., a local static
  74      variable).  */
  75   bitmap addressable_vars;
  76
  77   /* Free list of SSA_NAMEs.  */
  78   tree free_ssanames;
  79
  80   /* Hashtable holding definition for symbol.  If this field is not NULL, it
  81      means that the first reference to this variable in the function is a
  82      USE or a VUSE.  In those cases, the SSA renamer creates an SSA name
  83      for this variable with an empty defining statement.  */
  84   htab_t GTY((param_is (struct int_tree_map))) default_defs;
  85
  86   /* 'true' after aliases have been computed (see compute_may_aliases).  */
  87   unsigned int aliases_computed_p : 1;
  88
  89   /* True if the code is in ssa form.  */
  90   unsigned int in_ssa_p : 1;
  91 };
  92
  93 /* Accessors for internal use only.  Generic code should use abstraction
  94    provided by tree-flow-inline.h or specific modules.  */
  95 #define FREE_SSANAMES(fun) (fun)->gimple_df->free_ssanames
  96 #define SSANAMES(fun) (fun)->gimple_df->ssa_names
  97 #define MODIFIED_NORETURN_CALLS(fun) (fun)->gimple_df->modified_noreturn_calls
  98 #define DEFAULT_DEFS(fun) (fun)->gimple_df->default_defs
  99
 100 typedef struct
 101 {
 102   htab_t htab;
 103   PTR *slot;
 104   PTR *limit;
 105 } htab_iterator;
 106
 107 /* Iterate through the elements of hashtable HTAB, using htab_iterator ITER,
 108    storing each element in RESULT, which is of type TYPE.  */
 109 #define FOR_EACH_HTAB_ELEMENT(HTAB, RESULT, TYPE, ITER) \
 110   for (RESULT = (TYPE) first_htab_element (&(ITER), (HTAB)); \
 111         !end_htab_p (&(ITER)); \
 112         RESULT = (TYPE) next_htab_element (&(ITER)))
 113
 114 /*---------------------------------------------------------------------------
 115                       Attributes for SSA_NAMEs.
 116
 117   NOTE: These structures are stored in struct tree_ssa_name
 118   but are only used by the tree optimizers, so it makes better sense
 119   to declare them here to avoid recompiling unrelated files when
 120   making changes.
 121 ---------------------------------------------------------------------------*/
 122
 123 /* Aliasing information for SSA_NAMEs representing pointer variables.  */
 124 struct ptr_info_def GTY(())
 125 {
 126   /* Nonzero if points-to analysis couldn't determine where this pointer
 127      is pointing to.  */
 128   unsigned int pt_anything : 1;
 129
 130   /* Nonzero if the value of this pointer escapes the current function.  */
 131   unsigned int value_escapes_p : 1;
 132
 133   /* Nonzero if this pointer is dereferenced.  */
 134   unsigned int is_dereferenced : 1;
 135
 136   /* Nonzero if this pointer points to a global variable.  */
 137   unsigned int pt_global_mem : 1;
 138
 139   /* Nonzero if this pointer points to NULL.  */
 140   unsigned int pt_null : 1;
 141
 142   /* Set of variables that this pointer may point to.  */
 143   bitmap pt_vars;
 144
 145   /* If this pointer has been dereferenced, and points-to information is
 146      more precise than type-based aliasing, indirect references to this
 147      pointer will be represented by this memory tag, instead of the type
 148      tag computed by TBAA.  */
 149   tree name_mem_tag;
 150
 151   /* Mask of reasons this pointer's value escapes the function  */
 152   unsigned int escape_mask;
 153 };
 154
 155
 156 /*---------------------------------------------------------------------------
 157                    Tree annotations stored in tree_common.ann
 158 ---------------------------------------------------------------------------*/
 159 enum tree_ann_type { TREE_ANN_COMMON, VAR_ANN, FUNCTION_ANN, STMT_ANN };
 160
 161 struct tree_ann_common_d GTY(())
 162 {
 163   /* Annotation type.  */
 164   enum tree_ann_type type;
 165
 166  /* Auxiliary info specific to a pass.  At all times, this
 167     should either point to valid data or be NULL.  */
 168   PTR GTY ((skip (""))) aux;
 169
 170   /* The value handle for this expression.  Used by GVN-PRE.  */
 171   tree GTY((skip)) value_handle;
 172 };
 173
 174 /* It is advantageous to avoid things like life analysis for variables which
 175    do not need PHI nodes.  This enum describes whether or not a particular
 176    variable may need a PHI node.  */
 177
 178 enum need_phi_state {
 179   /* This is the default.  If we are still in this state after finding
 180      all the definition and use sites, then we will assume the variable
 181      needs PHI nodes.  This is probably an overly conservative assumption.  */
 182   NEED_PHI_STATE_UNKNOWN,
 183
 184   /* This state indicates that we have seen one or more sets of the
 185      variable in a single basic block and that the sets dominate all
 186      uses seen so far.  If after finding all definition and use sites
 187      we are still in this state, then the variable does not need any
 188      PHI nodes.  */
 189   NEED_PHI_STATE_NO,
 190
 191   /* This state indicates that we have either seen multiple definitions of
 192      the variable in multiple blocks, or that we encountered a use in a
 193      block that was not dominated by the block containing the set(s) of
 194      this variable.  This variable is assumed to need PHI nodes.  */
 195   NEED_PHI_STATE_MAYBE
 196 };
 197
 198 struct subvar;
 199 typedef struct subvar *subvar_t;
 200
 201 /* This structure represents a fake sub-variable for a structure field.  */
 202 struct subvar GTY(())
 203 {
 204   /* Fake variable.  */
 205   tree var;
 206
 207   /* Next subvar for this structure.  */
 208   subvar_t next;
 209 };
 210
 211 struct var_ann_d GTY(())
 212 {
 213   struct tree_ann_common_d common;
 214
 215   /* Used by the out of SSA pass to determine whether this variable has
 216      been seen yet or not.  */
 217   unsigned out_of_ssa_tag : 1;
 218
 219   /* Used when building root_var structures in tree_ssa_live.[ch].  */
 220   unsigned root_var_processed : 1;
 221
 222   /* Nonzero if this variable is in the alias set of another variable.  */
 223   unsigned is_aliased : 1;
 224
 225   /* Nonzero if this variable was used after SSA optimizations were
 226      applied.  We set this when translating out of SSA form.  */
 227   unsigned used : 1;
 228
 229   /* This field indicates whether or not the variable may need PHI nodes.
 230      See the enum's definition for more detailed information about the
 231      states.  */
 232   ENUM_BITFIELD (need_phi_state) need_phi_state : 2;
 233
 234   /* Used during operand processing to determine if this variable is already
 235      in the vuse list.  */
 236   unsigned in_vuse_list : 1;
 237
 238   /* Used during operand processing to determine if this variable is already
 239      in the v_may_def list.  */
 240   unsigned in_v_may_def_list : 1;
 241
 242   /* True for HEAP and PARM_NOALIAS artificial variables.  */
 243   unsigned is_heapvar : 1;
 244
 245   /* An artificial variable representing the memory location pointed-to by
 246      all the pointer symbols that flow-insensitive alias analysis
 247      (mostly type-based) considers to be aliased.  If the variable is
 248      not a pointer or if it is never dereferenced, this must be NULL.  */
 249   tree symbol_mem_tag;
 250
 251   /* Variables that may alias this variable.  */
 252   VEC(tree, gc) *may_aliases;
 253
 254   /* Used when going out of SSA form to indicate which partition this
 255      variable represents storage for.  */
 256   unsigned partition;
 257
 258   /* Used by the root-var object in tree-ssa-live.[ch].  */
 259   unsigned root_index;
 260
 261   /* During into-ssa and the dominator optimizer, this field holds the
 262      current version of this variable (an SSA_NAME).  */
 263   tree current_def;
 264
 265   /* If this variable is a structure, this fields holds a list of
 266      symbols representing each of the fields of the structure.  */
 267   subvar_t subvars;
 268
 269   /* Mask of values saying the reasons why this variable has escaped
 270      the function.  */
 271   unsigned int escape_mask;
 272 };
 273
 274 struct function_ann_d GTY(())
 275 {
 276   struct tree_ann_common_d common;
 277
 278   /* Pointer to the structure that contains the sets of global
 279      variables modified by function calls.  This field is only used
 280      for FUNCTION_DECLs.  */
 281   ipa_reference_vars_info_t GTY ((skip)) reference_vars_info;
 282 };
 283
 284 typedef struct immediate_use_iterator_d
 285 {
 286   /* This is the current use the iterator is processing.  */
 287   ssa_use_operand_t *imm_use;
 288   /* This marks the last use in the list (use node from SSA_NAME)  */
 289   ssa_use_operand_t *end_p;
 290   /* This node is inserted and used to mark the end of the uses for a stmt.  */
 291   ssa_use_operand_t iter_node;
 292   /* This is the next ssa_name to visit.  IMM_USE may get removed before
 293      the next one is traversed to, so it must be cached early.  */
 294   ssa_use_operand_t *next_imm_name;
 295 } imm_use_iterator;
 296
 297
 298 /* Use this iterator when simply looking at stmts.  Adding, deleting or
 299    modifying stmts will cause this iterator to malfunction.  */
 300
 301 #define FOR_EACH_IMM_USE_FAST(DEST, ITER, SSAVAR)                       \
 302   for ((DEST) = first_readonly_imm_use (&(ITER), (SSAVAR));     \
 303        !end_readonly_imm_use_p (&(ITER));                       \
 304        (DEST) = next_readonly_imm_use (&(ITER)))
 305
 306 /* Use this iterator to visit each stmt which has a use of SSAVAR.  */
 307
 308 #define FOR_EACH_IMM_USE_STMT(STMT, ITER, SSAVAR)               \
 309   for ((STMT) = first_imm_use_stmt (&(ITER), (SSAVAR));         \
 310        !end_imm_use_stmt_p (&(ITER));                           \
 311        (STMT) = next_imm_use_stmt (&(ITER)))
 312
 313 /* Use this to terminate the FOR_EACH_IMM_USE_STMT loop early.  Failure to
 314    do so will result in leaving a iterator marker node in the immediate
 315    use list, and nothing good will come from that.   */
 316 #define BREAK_FROM_IMM_USE_STMT(ITER)                           \
 317    {                                                            \
 318      end_imm_use_stmt_traverse (&(ITER));                       \
 319      break;                                                     \
 320    }
 321
 322
 323 /* Use this iterator in combination with FOR_EACH_IMM_USE_STMT to
 324    get access to each occurrence of ssavar on the stmt returned by
 325    that iterator..  for instance:
 326
 327      FOR_EACH_IMM_USE_STMT (stmt, iter, var)
 328        {
 329          FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
 330            {
 331              SET_USE (use_p) = blah;
 332            }
 333          update_stmt (stmt);
 334        }                                                         */
 335
 336 #define FOR_EACH_IMM_USE_ON_STMT(DEST, ITER)                    \
 337   for ((DEST) = first_imm_use_on_stmt (&(ITER));                \
 338        !end_imm_use_on_stmt_p (&(ITER));                        \
 339        (DEST) = next_imm_use_on_stmt (&(ITER)))
 340
 341
 342
 343 struct stmt_ann_d GTY(())
 344 {
 345   struct tree_ann_common_d common;
 346
 347   /* Nonzero if the statement has been modified (meaning that the operands
 348      need to be scanned again).  */
 349   unsigned modified : 1;
 350
 351   /* Nonzero if the statement makes references to volatile storage.  */
 352   unsigned has_volatile_ops : 1;
 353
 354   /* Nonzero if the statement makes a function call that may clobber global
 355      and local addressable variables.  */
 356   unsigned makes_clobbering_call : 1;
 357
 358   /* Basic block that contains this statement.  */
 359   basic_block bb;
 360
 361   /* Operand cache for stmt.  */
 362   struct stmt_operands_d GTY ((skip (""))) operands;
 363
 364   /* Set of variables that have had their address taken in the statement.  */
 365   bitmap addresses_taken;
 366
 367   /* Unique identifier for this statement.  These ID's are to be created
 368      by each pass on an as-needed basis in any order convenient for the
 369      pass which needs statement UIDs.  */
 370   unsigned int uid;
 371
 372   /* Linked list of histograms for value-based profiling.  This is really a
 373      struct histogram_value*.  We use void* to avoid having to export that
 374      everywhere, and to avoid having to put it in GC memory.  */
 375
 376   void * GTY ((skip (""))) histograms;
 377 };
 378
 379 union tree_ann_d GTY((desc ("ann_type ((tree_ann_t)&%h)")))
 380 {
 381   struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
 382   struct var_ann_d GTY((tag ("VAR_ANN"))) vdecl;
 383   struct function_ann_d GTY((tag ("FUNCTION_ANN"))) fdecl;
 384   struct stmt_ann_d GTY((tag ("STMT_ANN"))) stmt;
 385 };
 386
 387 typedef union tree_ann_d *tree_ann_t;
 388 typedef struct var_ann_d *var_ann_t;
 389 typedef struct function_ann_d *function_ann_t;
 390 typedef struct stmt_ann_d *stmt_ann_t;
 391 typedef struct tree_ann_common_d *tree_ann_common_t;
 392
 393 static inline tree_ann_common_t tree_common_ann (tree);
 394 static inline tree_ann_common_t get_tree_common_ann (tree);
 395 static inline var_ann_t var_ann (tree);
 396 static inline var_ann_t get_var_ann (tree);
 397 static inline function_ann_t function_ann (tree);
 398 static inline function_ann_t get_function_ann (tree);
 399 static inline stmt_ann_t stmt_ann (tree);
 400 static inline bool has_stmt_ann (tree);
 401 static inline stmt_ann_t get_stmt_ann (tree);
 402 static inline enum tree_ann_type ann_type (tree_ann_t);
 403 static inline basic_block bb_for_stmt (tree);
 404 extern void set_bb_for_stmt (tree, basic_block);
 405 static inline bool noreturn_call_p (tree);
 406 static inline void update_stmt (tree);
 407 static inline bool stmt_modified_p (tree);
 408 static inline VEC(tree, gc) *may_aliases (tree);
 409 static inline int get_lineno (tree);
 410 static inline const char *get_filename (tree);
 411 static inline bool is_exec_stmt (tree);
 412 static inline bool is_label_stmt (tree);
 413 static inline bitmap addresses_taken (tree);
 414
 415 /*---------------------------------------------------------------------------
 416                   Structure representing predictions in tree level.
 417 ---------------------------------------------------------------------------*/
 418 struct edge_prediction GTY((chain_next ("%h.ep_next")))
 419 {
 420   struct edge_prediction *ep_next;
 421   edge ep_edge;
 422   enum br_predictor ep_predictor;
 423   int ep_probability;
 424 };
 425
 426 /* Accessors for basic block annotations.  */
 427 static inline tree phi_nodes (basic_block);
 428 static inline void set_phi_nodes (basic_block, tree);
 429
 430 /*---------------------------------------------------------------------------
 431                               Global declarations
 432 ---------------------------------------------------------------------------*/
 433 struct int_tree_map GTY(())
 434 {
 435
 436   unsigned int uid;
 437   tree to;
 438 };
 439
 440 extern unsigned int int_tree_map_hash (const void *);
 441 extern int int_tree_map_eq (const void *, const void *);
 442
 443 typedef struct
 444 {
 445   htab_iterator hti;
 446 } referenced_var_iterator;
 447
 448
 449 /* This macro loops over all the referenced vars, one at a time, putting the
 450    current var in VAR.  Note:  You are not allowed to add referenced variables
 451    to the hashtable while using this macro.  Doing so may cause it to behave
 452    erratically.  */
 453
 454 #define FOR_EACH_REFERENCED_VAR(VAR, ITER) \
 455   for ((VAR) = first_referenced_var (&(ITER)); \
 456        !end_referenced_vars_p (&(ITER)); \
 457        (VAR) = next_referenced_var (&(ITER)))
 458
 459
 460 typedef struct
 461 {
 462   int i;
 463 } safe_referenced_var_iterator;
 464
 465 /* This macro loops over all the referenced vars, one at a time, putting the
 466    current var in VAR.  You are allowed to add referenced variables during the
 467    execution of this macro, however, the macro will not iterate over them.  It
 468    requires a temporary vector of trees, VEC, whose lifetime is controlled by
 469    the caller.  The purpose of the vector is to temporarily store the
 470    referenced_variables hashtable so that adding referenced variables does not
 471    affect the hashtable.  */
 472
 473 #define FOR_EACH_REFERENCED_VAR_SAFE(VAR, VEC, ITER) \
 474   for ((ITER).i = 0, fill_referenced_var_vec (&(VEC)); \
 475        VEC_iterate (tree, (VEC), (ITER).i, (VAR)); \
 476        (ITER).i++)
 477
 478 extern tree referenced_var_lookup (unsigned int);
 479 extern bool referenced_var_check_and_insert (tree);
 480 #define num_referenced_vars htab_elements (gimple_referenced_vars (cfun))
 481 #define referenced_var(i) referenced_var_lookup (i)
 482
 483 #define num_ssa_names (VEC_length (tree, cfun->gimple_df->ssa_names))
 484 #define ssa_name(i) (VEC_index (tree, cfun->gimple_df->ssa_names, (i)))
 485
 486 /* Macros for showing usage statistics.  */
 487 #define SCALE(x) ((unsigned long) ((x) < 1024*10        \
 488                   ? (x)                                 \
 489                   : ((x) < 1024*1024*10                 \
 490                      ? (x) / 1024                       \
 491                      : (x) / (1024*1024))))
 492
 493 #define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
 494
 495 #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
 496
 497 /*---------------------------------------------------------------------------
 498                               Block iterators
 499 ---------------------------------------------------------------------------*/
 500
 501 typedef struct {
 502   tree_stmt_iterator tsi;
 503   basic_block bb;
 504 } block_stmt_iterator;
 505
 506 static inline block_stmt_iterator bsi_start (basic_block);
 507 static inline block_stmt_iterator bsi_last (basic_block);
 508 static inline block_stmt_iterator bsi_after_labels (basic_block);
 509 block_stmt_iterator bsi_for_stmt (tree);
 510 static inline bool bsi_end_p (block_stmt_iterator);
 511 static inline void bsi_next (block_stmt_iterator *);
 512 static inline void bsi_prev (block_stmt_iterator *);
 513 static inline tree bsi_stmt (block_stmt_iterator);
 514 static inline tree * bsi_stmt_ptr (block_stmt_iterator);
 515
 516 extern void bsi_remove (block_stmt_iterator *, bool);
 517 extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
 518 extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
 519 extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
 520
 521 enum bsi_iterator_update
 522 {
 523   /* Note that these are intentionally in the same order as TSI_FOO.  They
 524      mean exactly the same as their TSI_* counterparts.  */
 525   BSI_NEW_STMT,
 526   BSI_SAME_STMT,
 527   BSI_CHAIN_START,
 528   BSI_CHAIN_END,
 529   BSI_CONTINUE_LINKING
 530 };
 531
 532 extern void bsi_insert_before (block_stmt_iterator *, tree,
 533                                enum bsi_iterator_update);
 534 extern void bsi_insert_after (block_stmt_iterator *, tree,
 535                               enum bsi_iterator_update);
 536
 537 extern void bsi_replace (const block_stmt_iterator *, tree, bool);
 538
 539 /*---------------------------------------------------------------------------
 540                               OpenMP Region Tree
 541 ---------------------------------------------------------------------------*/
 542
 543 /* Parallel region information.  Every parallel and workshare
 544    directive is enclosed between two markers, the OMP_* directive
 545    and a corresponding OMP_RETURN statement.  */
 546
 547 struct omp_region
 548 {
 549   /* The enclosing region.  */
 550   struct omp_region *outer;
 551
 552   /* First child region.  */
 553   struct omp_region *inner;
 554
 555   /* Next peer region.  */
 556   struct omp_region *next;
 557
 558   /* Block containing the omp directive as its last stmt.  */
 559   basic_block entry;
 560
 561   /* Block containing the OMP_RETURN as its last stmt.  */
 562   basic_block exit;
 563
 564   /* Block containing the OMP_CONTINUE as its last stmt.  */
 565   basic_block cont;
 566
 567   /* If this is a combined parallel+workshare region, this is a list
 568      of additional arguments needed by the combined parallel+workshare
 569      library call.  */
 570   tree ws_args;
 571
 572   /* The code for the omp directive of this region.  */
 573   enum tree_code type;
 574
 575   /* Schedule kind, only used for OMP_FOR type regions.  */
 576   enum omp_clause_schedule_kind sched_kind;
 577
 578   /* True if this is a combined parallel+workshare region.  */
 579   bool is_combined_parallel;
 580 };
 581
 582 extern struct omp_region *root_omp_region;
 583 extern struct omp_region *new_omp_region (basic_block, enum tree_code,
 584                                           struct omp_region *);
 585 extern void free_omp_regions (void);
 586
 587 /*---------------------------------------------------------------------------
 588                               Function prototypes
 589 ---------------------------------------------------------------------------*/
 590 /* In tree-cfg.c  */
 591
 592 /* Location to track pending stmt for edge insertion.  */
 593 #define PENDING_STMT(e) ((e)->insns.t)
 594
 595 extern void delete_tree_cfg_annotations (void);
 596 extern void disband_implicit_edges (void);
 597 extern bool stmt_ends_bb_p (tree);
 598 extern bool is_ctrl_stmt (tree);
 599 extern bool is_ctrl_altering_stmt (tree);
 600 extern bool computed_goto_p (tree);
 601 extern bool simple_goto_p (tree);
 602 extern bool tree_can_make_abnormal_goto (tree);
 603 extern basic_block single_noncomplex_succ (basic_block bb);
 604 extern void tree_dump_bb (basic_block, FILE *, int);
 605 extern void debug_tree_bb (basic_block);
 606 extern basic_block debug_tree_bb_n (int);
 607 extern void dump_tree_cfg (FILE *, int);
 608 extern void debug_tree_cfg (int);
 609 extern void dump_cfg_stats (FILE *);
 610 extern void debug_cfg_stats (void);
 611 extern void debug_loop_ir (void);
 612 extern void print_loop_ir (FILE *);
 613 extern void cleanup_dead_labels (void);
 614 extern void group_case_labels (void);
 615 extern tree first_stmt (basic_block);
 616 extern tree last_stmt (basic_block);
 617 extern tree *last_stmt_ptr (basic_block);
 618 extern tree last_and_only_stmt (basic_block);
 619 extern edge find_taken_edge (basic_block, tree);
 620 extern basic_block label_to_block_fn (struct function *, tree);
 621 #define label_to_block(t) (label_to_block_fn (cfun, t))
 622 extern void bsi_insert_on_edge (edge, tree);
 623 extern basic_block bsi_insert_on_edge_immediate (edge, tree);
 624 extern void bsi_commit_one_edge_insert (edge, basic_block *);
 625 extern void bsi_commit_edge_inserts (void);
 626 extern void notice_special_calls (tree);
 627 extern void clear_special_calls (void);
 628 extern void verify_stmts (void);
 629 extern tree tree_block_label (basic_block);
 630 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
 631 extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
 632                                         basic_block *);
 633 extern void add_phi_args_after_copy_bb (basic_block);
 634 extern void add_phi_args_after_copy (basic_block *, unsigned);
 635 extern bool tree_purge_dead_abnormal_call_edges (basic_block);
 636 extern bool tree_purge_dead_eh_edges (basic_block);
 637 extern bool tree_purge_all_dead_eh_edges (bitmap);
 638 extern tree gimplify_val (block_stmt_iterator *, tree, tree);
 639 extern tree gimplify_build1 (block_stmt_iterator *, enum tree_code,
 640                              tree, tree);
 641 extern tree gimplify_build2 (block_stmt_iterator *, enum tree_code,
 642                              tree, tree, tree);
 643 extern tree gimplify_build3 (block_stmt_iterator *, enum tree_code,
 644                              tree, tree, tree, tree);
 645 extern void init_empty_tree_cfg (void);
 646 extern void fold_cond_expr_cond (void);
 647 extern void make_abnormal_goto_edges (basic_block, bool);
 648 extern void replace_uses_by (tree, tree);
 649 extern void start_recording_case_labels (void);
 650 extern void end_recording_case_labels (void);
 651 extern basic_block move_sese_region_to_fn (struct function *, basic_block,
 652                                            basic_block);
 653
 654 /* In tree-cfgcleanup.c  */
 655 extern bool cleanup_tree_cfg (void);
 656 extern void cleanup_tree_cfg_loop (void);
 657
 658 /* In tree-pretty-print.c.  */
 659 extern void dump_generic_bb (FILE *, basic_block, int, int);
 660
 661 /* In tree-dfa.c  */
 662 extern var_ann_t create_var_ann (tree);
 663 extern function_ann_t create_function_ann (tree);
 664 extern stmt_ann_t create_stmt_ann (tree);
 665 extern tree_ann_common_t create_tree_common_ann (tree);
 666 extern void dump_dfa_stats (FILE *);
 667 extern void debug_dfa_stats (void);
 668 extern void debug_referenced_vars (void);
 669 extern void dump_referenced_vars (FILE *);
 670 extern void dump_variable (FILE *, tree);
 671 extern void debug_variable (tree);
 672 extern void dump_subvars_for (FILE *, tree);
 673 extern void debug_subvars_for (tree);
 674 extern tree get_virtual_var (tree);
 675 extern void add_referenced_var (tree);
 676 extern void mark_new_vars_to_rename (tree);
 677 extern void find_new_referenced_vars (tree *);
 678
 679 extern tree make_rename_temp (tree, const char *);
 680 extern void set_default_def (tree, tree);
 681 extern tree gimple_default_def (struct function *, tree);
 682
 683 /* In tree-phinodes.c  */
 684 extern void reserve_phi_args_for_new_edge (basic_block);
 685 extern tree create_phi_node (tree, basic_block);
 686 extern void add_phi_arg (tree, tree, edge);
 687 extern void remove_phi_args (edge);
 688 extern void remove_phi_node (tree, tree);
 689 extern tree phi_reverse (tree);
 690
 691 /* In gimple-low.c  */
 692 extern void record_vars_into (tree, tree);
 693 extern void record_vars (tree);
 694 extern bool block_may_fallthru (tree);
 695
 696 /* In tree-ssa-alias.c  */
 697 extern void dump_may_aliases_for (FILE *, tree);
 698 extern void debug_may_aliases_for (tree);
 699 extern void dump_alias_info (FILE *);
 700 extern void debug_alias_info (void);
 701 extern void dump_points_to_info (FILE *);
 702 extern void debug_points_to_info (void);
 703 extern void dump_points_to_info_for (FILE *, tree);
 704 extern void debug_points_to_info_for (tree);
 705 extern bool may_be_aliased (tree);
 706 extern bool is_aliased_with (tree, tree);
 707 extern struct ptr_info_def *get_ptr_info (tree);
 708 extern void new_type_alias (tree, tree, tree);
 709 extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *, bool *);
 710 static inline subvar_t get_subvars_for_var (tree);
 711 static inline tree get_subvar_at (tree, unsigned HOST_WIDE_INT);
 712 static inline bool ref_contains_array_ref (tree);
 713 static inline bool array_ref_contains_indirect_ref (tree);
 714 extern tree get_ref_base_and_extent (tree, HOST_WIDE_INT *,
 715                                      HOST_WIDE_INT *, HOST_WIDE_INT *);
 716 static inline bool var_can_have_subvars (tree);
 717 static inline bool overlap_subvar (unsigned HOST_WIDE_INT,
 718                                    unsigned HOST_WIDE_INT,
 719                                    tree, bool *);
 720
 721 /* Call-back function for walk_use_def_chains().  At each reaching
 722    definition, a function with this prototype is called.  */
 723 typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
 724
 725
 726 /* In tree-ssa.c  */
 727 extern void init_tree_ssa (void);
 728 extern edge ssa_redirect_edge (edge, basic_block);
 729 extern void flush_pending_stmts (edge);
 730 extern bool tree_ssa_useless_type_conversion (tree);
 731 extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
 732 extern void verify_ssa (bool);
 733 extern void delete_tree_ssa (void);
 734 extern void register_new_def (tree, VEC(tree,heap) **);
 735 extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *, bool);
 736 extern bool stmt_references_memory_p (tree);
 737
 738 /* In tree-into-ssa.c  */
 739 void update_ssa (unsigned);
 740 void delete_update_ssa (void);
 741 void register_new_name_mapping (tree, tree);
 742 tree create_new_def_for (tree, tree, def_operand_p);
 743 bool need_ssa_update_p (void);
 744 bool name_mappings_registered_p (void);
 745 bool name_registered_for_update_p (tree);
 746 bitmap ssa_names_to_replace (void);
 747 void release_ssa_name_after_update_ssa (tree name);
 748 void compute_global_livein (bitmap, bitmap);
 749 tree duplicate_ssa_name (tree, tree);
 750 void mark_sym_for_renaming (tree);
 751 void mark_set_for_renaming (bitmap);
 752 tree get_current_def (tree);
 753 void set_current_def (tree, tree);
 754
 755 /* In tree-ssa-ccp.c  */
 756 bool fold_stmt (tree *);
 757 bool fold_stmt_inplace (tree);
 758 tree widen_bitfield (tree, tree, tree);
 759
 760 /* In tree-vrp.c  */
 761 tree vrp_evaluate_conditional (tree, bool);
 762 void simplify_stmt_using_ranges (tree);
 763
 764 /* In tree-ssa-dom.c  */
 765 extern void dump_dominator_optimization_stats (FILE *);
 766 extern void debug_dominator_optimization_stats (void);
 767 int loop_depth_of_name (tree);
 768
 769 /* In tree-ssa-copy.c  */
 770 extern void merge_alias_info (tree, tree);
 771 extern void propagate_value (use_operand_p, tree);
 772 extern void propagate_tree_value (tree *, tree);
 773 extern void replace_exp (use_operand_p, tree);
 774 extern bool may_propagate_copy (tree, tree);
 775 extern bool may_propagate_copy_into_asm (tree);
 776
 777 /* Affine iv.  */
 778
 779 typedef struct
 780 {
 781   /* Iv = BASE + STEP * i.  */
 782   tree base, step;
 783
 784   /* True if this iv does not overflow.  */
 785   bool no_overflow;
 786 } affine_iv;
 787
 788 /* Description of number of iterations of a loop.  All the expressions inside
 789    the structure can be evaluated at the end of the loop's preheader
 790    (and due to ssa form, also anywhere inside the body of the loop).  */
 791
 792 struct tree_niter_desc
 793 {
 794   tree assumptions;     /* The boolean expression.  If this expression evaluates
 795                            to false, then the other fields in this structure
 796                            should not be used; there is no guarantee that they
 797                            will be correct.  */
 798   tree may_be_zero;     /* The boolean expression.  If it evaluates to true,
 799                            the loop will exit in the first iteration (i.e.
 800                            its latch will not be executed), even if the niter
 801                            field says otherwise.  */
 802   tree niter;           /* The expression giving the number of iterations of
 803                            a loop (provided that assumptions == true and
 804                            may_be_zero == false), more precisely the number
 805                            of executions of the latch of the loop.  */
 806   tree additional_info; /* The boolean expression.  Sometimes we use additional
 807                            knowledge to simplify the other expressions
 808                            contained in this structure (for example the
 809                            knowledge about value ranges of operands on entry to
 810                            the loop).  If this is a case, conjunction of such
 811                            condition is stored in this field, so that we do not
 812                            lose the information: for example if may_be_zero
 813                            is (n <= 0) and niter is (unsigned) n, we know
 814                            that the number of iterations is at most
 815                            MAX_SIGNED_INT.  However if the (n <= 0) assumption
 816                            is eliminated (by looking at the guard on entry of
 817                            the loop), then the information would be lost.  */
 818
 819   /* The simplified shape of the exit condition.  The loop exits if
 820      CONTROL CMP BOUND is false, where CMP is one of NE_EXPR,
 821      LT_EXPR, or GT_EXPR, and step of CONTROL is positive if CMP is
 822      LE_EXPR and negative if CMP is GE_EXPR.  This information is used
 823      by loop unrolling.  */
 824   affine_iv control;
 825   tree bound;
 826   enum tree_code cmp;
 827 };
 828
 829 /* In tree-vectorizer.c */
 830 unsigned vectorize_loops (void);
 831 extern bool vect_can_force_dr_alignment_p (tree, unsigned int);
 832 extern tree get_vectype_for_scalar_type (tree);
 833
 834 /* In tree-ssa-phiopt.c */
 835 bool empty_block_p (basic_block);
 836
 837 /* In tree-ssa-loop*.c  */
 838
 839 void tree_ssa_lim (void);
 840 unsigned int tree_ssa_unswitch_loops (void);
 841 unsigned int canonicalize_induction_variables (void);
 842 unsigned int tree_unroll_loops_completely (bool);
 843 unsigned int tree_ssa_prefetch_arrays (void);
 844 unsigned int remove_empty_loops (void);
 845 void tree_ssa_iv_optimize (void);
 846
 847 bool number_of_iterations_exit (struct loop *, edge,
 848                                 struct tree_niter_desc *niter, bool);
 849 tree find_loop_niter (struct loop *, edge *);
 850 tree loop_niter_by_eval (struct loop *, edge);
 851 tree find_loop_niter_by_eval (struct loop *, edge *);
 852 void estimate_numbers_of_iterations (void);
 853 bool scev_probably_wraps_p (tree, tree, tree, struct loop *, bool);
 854 bool convert_affine_scev (struct loop *, tree, tree *, tree *, tree, bool);
 855
 856 bool nowrap_type_p (tree);
 857 enum ev_direction {EV_DIR_GROWS, EV_DIR_DECREASES, EV_DIR_UNKNOWN};
 858 enum ev_direction scev_direction (tree);
 859
 860 void free_numbers_of_iterations_estimates (void);
 861 void free_numbers_of_iterations_estimates_loop (struct loop *);
 862 void rewrite_into_loop_closed_ssa (bitmap, unsigned);
 863 void verify_loop_closed_ssa (void);
 864 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
 865 void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
 866                 tree *, tree *);
 867 void split_loop_exit_edge (edge);
 868 unsigned force_expr_to_var_cost (tree);
 869 void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
 870                                      bool *);
 871 basic_block ip_end_pos (struct loop *);
 872 basic_block ip_normal_pos (struct loop *);
 873 bool tree_duplicate_loop_to_header_edge (struct loop *, edge,
 874                                          unsigned int, sbitmap,
 875                                          edge, edge *,
 876                                          unsigned int *, int);
 877 struct loop *tree_ssa_loop_version (struct loop *, tree,
 878                                     basic_block *);
 879 tree expand_simple_operations (tree);
 880 void substitute_in_loop_info (struct loop *, tree, tree);
 881 edge single_dom_exit (struct loop *);
 882 bool can_unroll_loop_p (struct loop *loop, unsigned factor,
 883                         struct tree_niter_desc *niter);
 884 void tree_unroll_loop (struct loop *, unsigned,
 885                        edge, struct tree_niter_desc *);
 886 bool contains_abnormal_ssa_name_p (tree);
 887
 888 /* In tree-ssa-threadedge.c */
 889 extern bool potentially_threadable_block (basic_block);
 890 extern void thread_across_edge (tree, edge, bool,
 891                                 VEC(tree, heap) **, tree (*) (tree));
 892
 893 /* In tree-ssa-loop-im.c  */
 894 /* The possibilities of statement movement.  */
 895
 896 enum move_pos
 897   {
 898     MOVE_IMPOSSIBLE,            /* No movement -- side effect expression.  */
 899     MOVE_PRESERVE_EXECUTION,    /* Must not cause the non-executed statement
 900                                    become executed -- memory accesses, ... */
 901     MOVE_POSSIBLE               /* Unlimited movement.  */
 902   };
 903 extern enum move_pos movement_possibility (tree);
 904
 905 /* The reasons a variable may escape a function.  */
 906 enum escape_type
 907   {
 908     NO_ESCAPE = 0, /* Doesn't escape.  */
 909     ESCAPE_STORED_IN_GLOBAL = 1 << 1,
 910     ESCAPE_TO_ASM = 1 << 2,  /* Passed by address to an assembly
 911                                 statement.  */
 912     ESCAPE_TO_CALL = 1 << 3,  /* Escapes to a function call.  */
 913     ESCAPE_BAD_CAST = 1 << 4, /* Cast from pointer to integer */
 914     ESCAPE_TO_RETURN = 1 << 5, /* Returned from function.  */
 915     ESCAPE_TO_PURE_CONST = 1 << 6, /* Escapes to a pure or constant
 916                                       function call.  */
 917     ESCAPE_IS_GLOBAL = 1 << 7,  /* Is a global variable.  */
 918     ESCAPE_IS_PARM = 1 << 8, /* Is an incoming function parameter.  */
 919     ESCAPE_UNKNOWN = 1 << 9 /* We believe it escapes for some reason
 920                                not enumerated above.  */
 921   };
 922
 923 /* In tree-flow-inline.h  */
 924 static inline bool is_call_clobbered (tree);
 925 static inline void mark_call_clobbered (tree, unsigned int);
 926 static inline void set_is_used (tree);
 927 static inline bool unmodifiable_var_p (tree);
 928
 929 /* In tree-eh.c  */
 930 extern void make_eh_edges (tree);
 931 extern bool tree_could_trap_p (tree);
 932 extern bool tree_could_throw_p (tree);
 933 extern bool tree_can_throw_internal (tree);
 934 extern bool tree_can_throw_external (tree);
 935 extern int lookup_stmt_eh_region (tree);
 936 extern void add_stmt_to_eh_region (tree, int);
 937 extern bool remove_stmt_from_eh_region (tree);
 938 extern bool maybe_clean_or_replace_eh_stmt (tree, tree);
 939
 940 /* In tree-ssa-pre.c  */
 941 void add_to_value (tree, tree);
 942 void debug_value_expressions (tree);
 943 void print_value_expressions (FILE *, tree);
 944
 945
 946 /* In tree-vn.c  */
 947 bool expressions_equal_p (tree, tree);
 948 static inline tree get_value_handle (tree);
 949 hashval_t vn_compute (tree, hashval_t);
 950 void sort_vuses (VEC (tree, gc) *);
 951 tree vn_lookup_or_add (tree, tree);
 952 tree vn_lookup_or_add_with_vuses (tree, VEC (tree, gc) *);
 953 void vn_add (tree, tree);
 954 void vn_add_with_vuses (tree, tree, VEC (tree, gc) *);
 955 tree vn_lookup (tree, tree);
 956 tree vn_lookup_with_vuses (tree, VEC (tree, gc) *);
 957 void vn_init (void);
 958 void vn_delete (void);
 959
 960 /* In tree-ssa-sink.c  */
 961 bool is_hidden_global_store (tree);
 962
 963 /* In tree-sra.c  */
 964 void insert_edge_copies (tree, basic_block);
 965 void sra_insert_before (block_stmt_iterator *, tree);
 966 void sra_insert_after (block_stmt_iterator *, tree);
 967 void sra_init_cache (void);
 968 bool sra_type_can_be_decomposed_p (tree);
 969
 970 /* In tree-loop-linear.c  */
 971 extern void linear_transform_loops (void);
 972
 973 /* In tree-ssa-loop-ivopts.c  */
 974 bool expr_invariant_in_loop_p (struct loop *, tree);
 975 bool multiplier_allowed_in_address_p (HOST_WIDE_INT, enum machine_mode);
 976 unsigned multiply_by_cost (HOST_WIDE_INT, enum machine_mode);
 977
 978 /* In tree-ssa-threadupdate.c.  */
 979 extern bool thread_through_all_blocks (void);
 980 extern void register_jump_thread (edge, edge);
 981
 982 /* In gimplify.c  */
 983 tree force_gimple_operand (tree, tree *, bool, tree);
 984 tree force_gimple_operand_bsi (block_stmt_iterator *, tree, bool, tree);
 985
 986 /* In tree-ssa-structalias.c */
 987 bool find_what_p_points_to (tree);
 988
 989 /* In tree-ssa-live.c */
 990 extern void remove_unused_locals (void);
 991
 992 /* In tree-ssa-address.c  */
 993
 994 /* Affine combination of trees.  We keep track of at most MAX_AFF_ELTS elements
 995    to make things simpler; this is sufficient in most cases.  */
 996
 997 #define MAX_AFF_ELTS 8
 998
 999 struct affine_tree_combination
1000 {
1001   /* Type of the result of the combination.  */
1002   tree type;
1003
1004   /* Mask modulo that the operations are performed.  */
1005   unsigned HOST_WIDE_INT mask;
1006
1007   /* Constant offset.  */
1008   unsigned HOST_WIDE_INT offset;
1009
1010   /* Number of elements of the combination.  */
1011   unsigned n;
1012
1013   /* Elements and their coefficients.  */
1014   tree elts[MAX_AFF_ELTS];
1015   unsigned HOST_WIDE_INT coefs[MAX_AFF_ELTS];
1016
1017   /* Remainder of the expression.  */
1018   tree rest;
1019 };
1020
1021 /* Description of a memory address.  */
1022
1023 struct mem_address
1024 {
1025   tree symbol, base, index, step, offset;
1026 };
1027
1028 tree create_mem_ref (block_stmt_iterator *, tree,
1029                      struct affine_tree_combination *);
1030 rtx addr_for_mem_ref (struct mem_address *, bool);
1031 void get_address_description (tree, struct mem_address *);
1032 tree maybe_fold_tmr (tree);
1033
1034 /* This structure is simply used during pushing fields onto the fieldstack
1035    to track the offset of the field, since bitpos_of_field gives it relative
1036    to its immediate containing type, and we want it relative to the ultimate
1037    containing object.  */
1038
1039 struct fieldoff
1040 {
1041   tree type;
1042   tree size;
1043   tree decl;
1044   HOST_WIDE_INT offset;
1045 };
1046 typedef struct fieldoff fieldoff_s;
1047
1048 DEF_VEC_O(fieldoff_s);
1049 DEF_VEC_ALLOC_O(fieldoff_s,heap);
1050 int push_fields_onto_fieldstack (tree, VEC(fieldoff_s,heap) **,
1051                                  HOST_WIDE_INT, bool *);
1052 void sort_fieldstack (VEC(fieldoff_s,heap) *);
1053
1054 void init_alias_heapvars (void);
1055 void delete_alias_heapvars (void);
1056
1057 #include "tree-flow-inline.h"
1058
1059 void swap_tree_operands (tree, tree *, tree *);
1060
1061 extern void recalculate_used_alone (void);
1062 extern bool updating_used_alone;
1063
1064 int least_common_multiple (int, int);
1065
1066 #endif /* _TREE_FLOW_H  */