gcc/basic-block.h

   1 /* Define control flow data structures for the CFG.
   2    Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   3    2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GCC_BASIC_BLOCK_H
  22 #define GCC_BASIC_BLOCK_H
  23
  24 #include "predict.h"
  25 #include "vec.h"
  26 #include "function.h"
  27
  28 /* Type we use to hold basic block counters.  Should be at least
  29    64bit.  Although a counter cannot be negative, we use a signed
  30    type, because erroneous negative counts can be generated when the
  31    flow graph is manipulated by various optimizations.  A signed type
  32    makes those easy to detect.  */
  33 typedef HOST_WIDEST_INT gcov_type;
  34
  35 /* Control flow edge information.  */
  36 struct GTY(()) edge_def {
  37   /* The two blocks at the ends of the edge.  */
  38   struct basic_block_def *src;
  39   struct basic_block_def *dest;
  40
  41   /* Instructions queued on the edge.  */
  42   union edge_def_insns {
  43     gimple_seq GTY ((tag ("true"))) g;
  44     rtx GTY ((tag ("false"))) r;
  45   } GTY ((desc ("current_ir_type () == IR_GIMPLE"))) insns;
  46
  47   /* Auxiliary info specific to a pass.  */
  48   PTR GTY ((skip (""))) aux;
  49
  50   /* Location of any goto implicit in the edge and associated BLOCK.  */
  51   tree goto_block;
  52   location_t goto_locus;
  53
  54   /* The index number corresponding to this edge in the edge vector
  55      dest->preds.  */
  56   unsigned int dest_idx;
  57
  58   int flags;                    /* see EDGE_* below  */
  59   int probability;              /* biased by REG_BR_PROB_BASE */
  60   gcov_type count;              /* Expected number of executions calculated
  61                                    in profile.c  */
  62 };
  63
  64 DEF_VEC_P(edge);
  65 DEF_VEC_ALLOC_P(edge,gc);
  66 DEF_VEC_ALLOC_P(edge,heap);
  67
  68 #define EDGE_FALLTHRU           1       /* 'Straight line' flow */
  69 #define EDGE_ABNORMAL           2       /* Strange flow, like computed
  70                                            label, or eh */
  71 #define EDGE_ABNORMAL_CALL      4       /* Call with abnormal exit
  72                                            like an exception, or sibcall */
  73 #define EDGE_EH                 8       /* Exception throw */
  74 #define EDGE_FAKE               16      /* Not a real edge (profile.c) */
  75 #define EDGE_DFS_BACK           32      /* A backwards edge */
  76 #define EDGE_CAN_FALLTHRU       64      /* Candidate for straight line
  77                                            flow.  */
  78 #define EDGE_IRREDUCIBLE_LOOP   128     /* Part of irreducible loop.  */
  79 #define EDGE_SIBCALL            256     /* Edge from sibcall to exit.  */
  80 #define EDGE_LOOP_EXIT          512     /* Exit of a loop.  */
  81 #define EDGE_TRUE_VALUE         1024    /* Edge taken when controlling
  82                                            predicate is nonzero.  */
  83 #define EDGE_FALSE_VALUE        2048    /* Edge taken when controlling
  84                                            predicate is zero.  */
  85 #define EDGE_EXECUTABLE         4096    /* Edge is executable.  Only
  86                                            valid during SSA-CCP.  */
  87 #define EDGE_CROSSING           8192    /* Edge crosses between hot
  88                                            and cold sections, when we
  89                                            do partitioning.  */
  90 #define EDGE_ALL_FLAGS         16383
  91
  92 #define EDGE_COMPLEX    (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH)
  93
  94 /* Counter summary from the last set of coverage counts read by
  95    profile.c.  */
  96 extern const struct gcov_ctr_summary *profile_info;
  97
  98 /* Declared in cfgloop.h.  */
  99 struct loop;
 100
 101 /* Declared in tree-flow.h.  */
 102 struct edge_prediction;
 103 struct rtl_bb_info;
 104
 105 /* A basic block is a sequence of instructions with only entry and
 106    only one exit.  If any one of the instructions are executed, they
 107    will all be executed, and in sequence from first to last.
 108
 109    There may be COND_EXEC instructions in the basic block.  The
 110    COND_EXEC *instructions* will be executed -- but if the condition
 111    is false the conditionally executed *expressions* will of course
 112    not be executed.  We don't consider the conditionally executed
 113    expression (which might have side-effects) to be in a separate
 114    basic block because the program counter will always be at the same
 115    location after the COND_EXEC instruction, regardless of whether the
 116    condition is true or not.
 117
 118    Basic blocks need not start with a label nor end with a jump insn.
 119    For example, a previous basic block may just "conditionally fall"
 120    into the succeeding basic block, and the last basic block need not
 121    end with a jump insn.  Block 0 is a descendant of the entry block.
 122
 123    A basic block beginning with two labels cannot have notes between
 124    the labels.
 125
 126    Data for jump tables are stored in jump_insns that occur in no
 127    basic block even though these insns can follow or precede insns in
 128    basic blocks.  */
 129
 130 /* Basic block information indexed by block number.  */
 131 struct GTY((chain_next ("%h.next_bb"), chain_prev ("%h.prev_bb"))) basic_block_def {
 132   /* The edges into and out of the block.  */
 133   VEC(edge,gc) *preds;
 134   VEC(edge,gc) *succs;
 135
 136   /* Auxiliary info specific to a pass.  */
 137   PTR GTY ((skip (""))) aux;
 138
 139   /* Innermost loop containing the block.  */
 140   struct loop *loop_father;
 141
 142   /* The dominance and postdominance information node.  */
 143   struct et_node * GTY ((skip (""))) dom[2];
 144
 145   /* Previous and next blocks in the chain.  */
 146   struct basic_block_def *prev_bb;
 147   struct basic_block_def *next_bb;
 148
 149   union basic_block_il_dependent {
 150       struct gimple_bb_info * GTY ((tag ("0"))) gimple;
 151       struct rtl_bb_info * GTY ((tag ("1"))) rtl;
 152     } GTY ((desc ("((%1.flags & BB_RTL) != 0)"))) il;
 153
 154   /* Expected number of executions: calculated in profile.c.  */
 155   gcov_type count;
 156
 157   /* The index of this block.  */
 158   int index;
 159
 160   /* The loop depth of this block.  */
 161   int loop_depth;
 162
 163   /* Expected frequency.  Normalized to be in range 0 to BB_FREQ_MAX.  */
 164   int frequency;
 165
 166   /* The discriminator for this block.  */
 167   int discriminator;
 168
 169   /* Various flags.  See BB_* below.  */
 170   int flags;
 171 };
 172
 173 struct GTY(()) rtl_bb_info {
 174   /* The first and last insns of the block.  */
 175   rtx head_;
 176   rtx end_;
 177
 178   /* In CFGlayout mode points to insn notes/jumptables to be placed just before
 179      and after the block.   */
 180   rtx header;
 181   rtx footer;
 182
 183   /* This field is used by the bb-reorder and tracer passes.  */
 184   int visited;
 185 };
 186
 187 struct GTY(()) gimple_bb_info {
 188   /* Sequence of statements in this block.  */
 189   gimple_seq seq;
 190
 191   /* PHI nodes for this block.  */
 192   gimple_seq phi_nodes;
 193 };
 194
 195 DEF_VEC_P(basic_block);
 196 DEF_VEC_ALLOC_P(basic_block,gc);
 197 DEF_VEC_ALLOC_P(basic_block,heap);
 198
 199 #define BB_FREQ_MAX 10000
 200
 201 /* Masks for basic_block.flags.
 202
 203    BB_HOT_PARTITION and BB_COLD_PARTITION should be preserved throughout
 204    the compilation, so they are never cleared.
 205
 206    All other flags may be cleared by clear_bb_flags().  It is generally
 207    a bad idea to rely on any flags being up-to-date.  */
 208
 209 enum bb_flags
 210 {
 211   /* Only set on blocks that have just been created by create_bb.  */
 212   BB_NEW = 1 << 0,
 213
 214   /* Set by find_unreachable_blocks.  Do not rely on this being set in any
 215      pass.  */
 216   BB_REACHABLE = 1 << 1,
 217
 218   /* Set for blocks in an irreducible loop by loop analysis.  */
 219   BB_IRREDUCIBLE_LOOP = 1 << 2,
 220
 221   /* Set on blocks that may actually not be single-entry single-exit block.  */
 222   BB_SUPERBLOCK = 1 << 3,
 223
 224   /* Set on basic blocks that the scheduler should not touch.  This is used
 225      by SMS to prevent other schedulers from messing with the loop schedule.  */
 226   BB_DISABLE_SCHEDULE = 1 << 4,
 227
 228   /* Set on blocks that should be put in a hot section.  */
 229   BB_HOT_PARTITION = 1 << 5,
 230
 231   /* Set on blocks that should be put in a cold section.  */
 232   BB_COLD_PARTITION = 1 << 6,
 233
 234   /* Set on block that was duplicated.  */
 235   BB_DUPLICATED = 1 << 7,
 236
 237   /* Set if the label at the top of this block is the target of a non-local goto.  */
 238   BB_NON_LOCAL_GOTO_TARGET = 1 << 8,
 239
 240   /* Set on blocks that are in RTL format.  */
 241   BB_RTL = 1 << 9 ,
 242
 243   /* Set on blocks that are forwarder blocks.
 244      Only used in cfgcleanup.c.  */
 245   BB_FORWARDER_BLOCK = 1 << 10,
 246
 247   /* Set on blocks that cannot be threaded through.
 248      Only used in cfgcleanup.c.  */
 249   BB_NONTHREADABLE_BLOCK = 1 << 11,
 250
 251   /* Set on blocks that were modified in some way.  This bit is set in
 252      df_set_bb_dirty, but not cleared by df_analyze, so it can be used
 253      to test whether a block has been modified prior to a df_analyze
 254      call.  */
 255   BB_MODIFIED = 1 << 12
 256 };
 257
 258 /* Dummy flag for convenience in the hot/cold partitioning code.  */
 259 #define BB_UNPARTITIONED        0
 260
 261 /* Partitions, to be used when partitioning hot and cold basic blocks into
 262    separate sections.  */
 263 #define BB_PARTITION(bb) ((bb)->flags & (BB_HOT_PARTITION|BB_COLD_PARTITION))
 264 #define BB_SET_PARTITION(bb, part) do {                                 \
 265   basic_block bb_ = (bb);                                               \
 266   bb_->flags = ((bb_->flags & ~(BB_HOT_PARTITION|BB_COLD_PARTITION))    \
 267                 | (part));                                              \
 268 } while (0)
 269
 270 #define BB_COPY_PARTITION(dstbb, srcbb) \
 271   BB_SET_PARTITION (dstbb, BB_PARTITION (srcbb))
 272
 273 /* State of dominance information.  */
 274
 275 enum dom_state
 276 {
 277   DOM_NONE,             /* Not computed at all.  */
 278   DOM_NO_FAST_QUERY,    /* The data is OK, but the fast query data are not usable.  */
 279   DOM_OK                /* Everything is ok.  */
 280 };
 281
 282 /* What sort of profiling information we have.  */
 283 enum profile_status_d
 284 {
 285   PROFILE_ABSENT,
 286   PROFILE_GUESSED,
 287   PROFILE_READ
 288 };
 289
 290 /* A structure to group all the per-function control flow graph data.
 291    The x_* prefixing is necessary because otherwise references to the
 292    fields of this struct are interpreted as the defines for backward
 293    source compatibility following the definition of this struct.  */
 294 struct GTY(()) control_flow_graph {
 295   /* Block pointers for the exit and entry of a function.
 296      These are always the head and tail of the basic block list.  */
 297   basic_block x_entry_block_ptr;
 298   basic_block x_exit_block_ptr;
 299
 300   /* Index by basic block number, get basic block struct info.  */
 301   VEC(basic_block,gc) *x_basic_block_info;
 302
 303   /* Number of basic blocks in this flow graph.  */
 304   int x_n_basic_blocks;
 305
 306   /* Number of edges in this flow graph.  */
 307   int x_n_edges;
 308
 309   /* The first free basic block number.  */
 310   int x_last_basic_block;
 311
 312   /* UIDs for LABEL_DECLs.  */
 313   int last_label_uid;
 314
 315   /* Mapping of labels to their associated blocks.  At present
 316      only used for the gimple CFG.  */
 317   VEC(basic_block,gc) *x_label_to_block_map;
 318
 319   enum profile_status_d x_profile_status;
 320
 321   /* Whether the dominators and the postdominators are available.  */
 322   enum dom_state x_dom_computed[2];
 323
 324   /* Number of basic blocks in the dominance tree.  */
 325   unsigned x_n_bbs_in_dom_tree[2];
 326
 327   /* Maximal number of entities in the single jumptable.  Used to estimate
 328      final flowgraph size.  */
 329   int max_jumptable_ents;
 330 };
 331
 332 /* Defines for accessing the fields of the CFG structure for function FN.  */
 333 #define ENTRY_BLOCK_PTR_FOR_FUNCTION(FN)     ((FN)->cfg->x_entry_block_ptr)
 334 #define EXIT_BLOCK_PTR_FOR_FUNCTION(FN)      ((FN)->cfg->x_exit_block_ptr)
 335 #define basic_block_info_for_function(FN)    ((FN)->cfg->x_basic_block_info)
 336 #define n_basic_blocks_for_function(FN)      ((FN)->cfg->x_n_basic_blocks)
 337 #define n_edges_for_function(FN)             ((FN)->cfg->x_n_edges)
 338 #define last_basic_block_for_function(FN)    ((FN)->cfg->x_last_basic_block)
 339 #define label_to_block_map_for_function(FN)  ((FN)->cfg->x_label_to_block_map)
 340 #define profile_status_for_function(FN)      ((FN)->cfg->x_profile_status)
 341
 342 #define BASIC_BLOCK_FOR_FUNCTION(FN,N) \
 343   (VEC_index (basic_block, basic_block_info_for_function(FN), (N)))
 344 #define SET_BASIC_BLOCK_FOR_FUNCTION(FN,N,BB) \
 345   (VEC_replace (basic_block, basic_block_info_for_function(FN), (N), (BB)))
 346
 347 /* Defines for textual backward source compatibility.  */
 348 #define ENTRY_BLOCK_PTR         (cfun->cfg->x_entry_block_ptr)
 349 #define EXIT_BLOCK_PTR          (cfun->cfg->x_exit_block_ptr)
 350 #define basic_block_info        (cfun->cfg->x_basic_block_info)
 351 #define n_basic_blocks          (cfun->cfg->x_n_basic_blocks)
 352 #define n_edges                 (cfun->cfg->x_n_edges)
 353 #define last_basic_block        (cfun->cfg->x_last_basic_block)
 354 #define label_to_block_map      (cfun->cfg->x_label_to_block_map)
 355 #define profile_status          (cfun->cfg->x_profile_status)
 356
 357 #define BASIC_BLOCK(N)          (VEC_index (basic_block, basic_block_info, (N)))
 358 #define SET_BASIC_BLOCK(N,BB)   (VEC_replace (basic_block, basic_block_info, (N), (BB)))
 359
 360 /* For iterating over basic blocks.  */
 361 #define FOR_BB_BETWEEN(BB, FROM, TO, DIR) \
 362   for (BB = FROM; BB != TO; BB = BB->DIR)
 363
 364 #define FOR_EACH_BB_FN(BB, FN) \
 365   FOR_BB_BETWEEN (BB, (FN)->cfg->x_entry_block_ptr->next_bb, (FN)->cfg->x_exit_block_ptr, next_bb)
 366
 367 #define FOR_EACH_BB(BB) FOR_EACH_BB_FN (BB, cfun)
 368
 369 #define FOR_EACH_BB_REVERSE_FN(BB, FN) \
 370   FOR_BB_BETWEEN (BB, (FN)->cfg->x_exit_block_ptr->prev_bb, (FN)->cfg->x_entry_block_ptr, prev_bb)
 371
 372 #define FOR_EACH_BB_REVERSE(BB) FOR_EACH_BB_REVERSE_FN(BB, cfun)
 373
 374 /* For iterating over insns in basic block.  */
 375 #define FOR_BB_INSNS(BB, INSN)                  \
 376   for ((INSN) = BB_HEAD (BB);                   \
 377        (INSN) && (INSN) != NEXT_INSN (BB_END (BB));     \
 378        (INSN) = NEXT_INSN (INSN))
 379
 380 /* For iterating over insns in basic block when we might remove the
 381    current insn.  */
 382 #define FOR_BB_INSNS_SAFE(BB, INSN, CURR)                       \
 383   for ((INSN) = BB_HEAD (BB), (CURR) = (INSN) ? NEXT_INSN ((INSN)): NULL;       \
 384        (INSN) && (INSN) != NEXT_INSN (BB_END (BB));     \
 385        (INSN) = (CURR), (CURR) = (INSN) ? NEXT_INSN ((INSN)) : NULL)
 386
 387 #define FOR_BB_INSNS_REVERSE(BB, INSN)          \
 388   for ((INSN) = BB_END (BB);                    \
 389        (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));    \
 390        (INSN) = PREV_INSN (INSN))
 391
 392 #define FOR_BB_INSNS_REVERSE_SAFE(BB, INSN, CURR)       \
 393   for ((INSN) = BB_END (BB),(CURR) = (INSN) ? PREV_INSN ((INSN)) : NULL;        \
 394        (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));    \
 395        (INSN) = (CURR), (CURR) = (INSN) ? PREV_INSN ((INSN)) : NULL)
 396
 397 /* Cycles through _all_ basic blocks, even the fake ones (entry and
 398    exit block).  */
 399
 400 #define FOR_ALL_BB(BB) \
 401   for (BB = ENTRY_BLOCK_PTR; BB; BB = BB->next_bb)
 402
 403 #define FOR_ALL_BB_FN(BB, FN) \
 404   for (BB = ENTRY_BLOCK_PTR_FOR_FUNCTION (FN); BB; BB = BB->next_bb)
 405
 406 \f
 407 /* Stuff for recording basic block info.  */
 408
 409 #define BB_HEAD(B)      (B)->il.rtl->head_
 410 #define BB_END(B)       (B)->il.rtl->end_
 411
 412 /* Special block numbers [markers] for entry and exit.
 413    Neither of them is supposed to hold actual statements.  */
 414 #define ENTRY_BLOCK (0)
 415 #define EXIT_BLOCK (1)
 416
 417 /* The two blocks that are always in the cfg.  */
 418 #define NUM_FIXED_BLOCKS (2)
 419
 420 #define set_block_for_insn(INSN, BB)  (BLOCK_FOR_INSN (INSN) = BB)
 421
 422 extern void compute_bb_for_insn (void);
 423 extern unsigned int free_bb_for_insn (void);
 424 extern void update_bb_for_insn (basic_block);
 425
 426 extern void insert_insn_on_edge (rtx, edge);
 427 basic_block split_edge_and_insert (edge, rtx);
 428
 429 extern void commit_one_edge_insertion (edge e);
 430 extern void commit_edge_insertions (void);
 431
 432 extern void remove_fake_edges (void);
 433 extern void remove_fake_exit_edges (void);
 434 extern void add_noreturn_fake_exit_edges (void);
 435 extern void connect_infinite_loops_to_exit (void);
 436 extern edge unchecked_make_edge (basic_block, basic_block, int);
 437 extern edge cached_make_edge (sbitmap, basic_block, basic_block, int);
 438 extern edge make_edge (basic_block, basic_block, int);
 439 extern edge make_single_succ_edge (basic_block, basic_block, int);
 440 extern void remove_edge_raw (edge);
 441 extern void redirect_edge_succ (edge, basic_block);
 442 extern edge redirect_edge_succ_nodup (edge, basic_block);
 443 extern void redirect_edge_pred (edge, basic_block);
 444 extern basic_block create_basic_block_structure (rtx, rtx, rtx, basic_block);
 445 extern void clear_bb_flags (void);
 446 extern int post_order_compute (int *, bool, bool);
 447 extern int inverted_post_order_compute (int *);
 448 extern int pre_and_rev_post_order_compute (int *, int *, bool);
 449 extern int dfs_enumerate_from (basic_block, int,
 450                                bool (*)(const_basic_block, const void *),
 451                                basic_block *, int, const void *);
 452 extern void compute_dominance_frontiers (struct bitmap_head_def *);
 453 extern bitmap compute_idf (bitmap, struct bitmap_head_def *);
 454 extern void dump_bb_info (basic_block, bool, bool, int, const char *, FILE *);
 455 extern void dump_edge_info (FILE *, edge, int);
 456 extern void brief_dump_cfg (FILE *);
 457 extern void clear_edges (void);
 458 extern void scale_bbs_frequencies_int (basic_block *, int, int, int);
 459 extern void scale_bbs_frequencies_gcov_type (basic_block *, int, gcov_type,
 460                                              gcov_type);
 461
 462 /* Structure to group all of the information to process IF-THEN and
 463    IF-THEN-ELSE blocks for the conditional execution support.  This
 464    needs to be in a public file in case the IFCVT macros call
 465    functions passing the ce_if_block data structure.  */
 466
 467 typedef struct ce_if_block
 468 {
 469   basic_block test_bb;                  /* First test block.  */
 470   basic_block then_bb;                  /* THEN block.  */
 471   basic_block else_bb;                  /* ELSE block or NULL.  */
 472   basic_block join_bb;                  /* Join THEN/ELSE blocks.  */
 473   basic_block last_test_bb;             /* Last bb to hold && or || tests.  */
 474   int num_multiple_test_blocks;         /* # of && and || basic blocks.  */
 475   int num_and_and_blocks;               /* # of && blocks.  */
 476   int num_or_or_blocks;                 /* # of || blocks.  */
 477   int num_multiple_test_insns;          /* # of insns in && and || blocks.  */
 478   int and_and_p;                        /* Complex test is &&.  */
 479   int num_then_insns;                   /* # of insns in THEN block.  */
 480   int num_else_insns;                   /* # of insns in ELSE block.  */
 481   int pass;                             /* Pass number.  */
 482
 483 #ifdef IFCVT_EXTRA_FIELDS
 484   IFCVT_EXTRA_FIELDS                    /* Any machine dependent fields.  */
 485 #endif
 486
 487 } ce_if_block_t;
 488
 489 /* This structure maintains an edge list vector.  */
 490 struct edge_list
 491 {
 492   int num_blocks;
 493   int num_edges;
 494   edge *index_to_edge;
 495 };
 496
 497 /* The base value for branch probability notes and edge probabilities.  */
 498 #define REG_BR_PROB_BASE  10000
 499
 500 /* This is the value which indicates no edge is present.  */
 501 #define EDGE_INDEX_NO_EDGE      -1
 502
 503 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 504    if there is no edge between the 2 basic blocks.  */
 505 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 506
 507 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 508    block which is either the pred or succ end of the indexed edge.  */
 509 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 510 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 511
 512 /* INDEX_EDGE returns a pointer to the edge.  */
 513 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 514
 515 /* Number of edges in the compressed edge list.  */
 516 #define NUM_EDGES(el)                   ((el)->num_edges)
 517
 518 /* BB is assumed to contain conditional jump.  Return the fallthru edge.  */
 519 #define FALLTHRU_EDGE(bb)               (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
 520                                          ? EDGE_SUCC ((bb), 0) : EDGE_SUCC ((bb), 1))
 521
 522 /* BB is assumed to contain conditional jump.  Return the branch edge.  */
 523 #define BRANCH_EDGE(bb)                 (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
 524                                          ? EDGE_SUCC ((bb), 1) : EDGE_SUCC ((bb), 0))
 525
 526 /* Return expected execution frequency of the edge E.  */
 527 #define EDGE_FREQUENCY(e)               (((e)->src->frequency \
 528                                           * (e)->probability \
 529                                           + REG_BR_PROB_BASE / 2) \
 530                                          / REG_BR_PROB_BASE)
 531
 532 /* Return nonzero if edge is critical.  */
 533 #define EDGE_CRITICAL_P(e)              (EDGE_COUNT ((e)->src->succs) >= 2 \
 534                                          && EDGE_COUNT ((e)->dest->preds) >= 2)
 535
 536 #define EDGE_COUNT(ev)                  VEC_length (edge, (ev))
 537 #define EDGE_I(ev,i)                    VEC_index  (edge, (ev), (i))
 538 #define EDGE_PRED(bb,i)                 VEC_index  (edge, (bb)->preds, (i))
 539 #define EDGE_SUCC(bb,i)                 VEC_index  (edge, (bb)->succs, (i))
 540
 541 /* Returns true if BB has precisely one successor.  */
 542
 543 static inline bool
 544 single_succ_p (const_basic_block bb)
 545 {
 546   return EDGE_COUNT (bb->succs) == 1;
 547 }
 548
 549 /* Returns true if BB has precisely one predecessor.  */
 550
 551 static inline bool
 552 single_pred_p (const_basic_block bb)
 553 {
 554   return EDGE_COUNT (bb->preds) == 1;
 555 }
 556
 557 /* Returns the single successor edge of basic block BB.  Aborts if
 558    BB does not have exactly one successor.  */
 559
 560 static inline edge
 561 single_succ_edge (const_basic_block bb)
 562 {
 563 #ifdef ENABLE_CHECKING
 564   gcc_assert (single_succ_p (bb));
 565 #endif
 566   return EDGE_SUCC (bb, 0);
 567 }
 568
 569 /* Returns the single predecessor edge of basic block BB.  Aborts
 570    if BB does not have exactly one predecessor.  */
 571
 572 static inline edge
 573 single_pred_edge (const_basic_block bb)
 574 {
 575 #ifdef ENABLE_CHECKING
 576   gcc_assert (single_pred_p (bb));
 577 #endif
 578   return EDGE_PRED (bb, 0);
 579 }
 580
 581 /* Returns the single successor block of basic block BB.  Aborts
 582    if BB does not have exactly one successor.  */
 583
 584 static inline basic_block
 585 single_succ (const_basic_block bb)
 586 {
 587   return single_succ_edge (bb)->dest;
 588 }
 589
 590 /* Returns the single predecessor block of basic block BB.  Aborts
 591    if BB does not have exactly one predecessor.*/
 592
 593 static inline basic_block
 594 single_pred (const_basic_block bb)
 595 {
 596   return single_pred_edge (bb)->src;
 597 }
 598
 599 /* Iterator object for edges.  */
 600
 601 typedef struct {
 602   unsigned index;
 603   VEC(edge,gc) **container;
 604 } edge_iterator;
 605
 606 static inline VEC(edge,gc) *
 607 ei_container (edge_iterator i)
 608 {
 609 #ifdef ENABLE_CHECKING
 610   gcc_assert (i.container);
 611 #endif
 612   return *i.container;
 613 }
 614
 615 #define ei_start(iter) ei_start_1 (&(iter))
 616 #define ei_last(iter) ei_last_1 (&(iter))
 617
 618 /* Return an iterator pointing to the start of an edge vector.  */
 619 static inline edge_iterator
 620 ei_start_1 (VEC(edge,gc) **ev)
 621 {
 622   edge_iterator i;
 623
 624   i.index = 0;
 625   i.container = ev;
 626
 627   return i;
 628 }
 629
 630 /* Return an iterator pointing to the last element of an edge
 631    vector.  */
 632 static inline edge_iterator
 633 ei_last_1 (VEC(edge,gc) **ev)
 634 {
 635   edge_iterator i;
 636
 637   i.index = EDGE_COUNT (*ev) - 1;
 638   i.container = ev;
 639
 640   return i;
 641 }
 642
 643 /* Is the iterator `i' at the end of the sequence?  */
 644 static inline bool
 645 ei_end_p (edge_iterator i)
 646 {
 647   return (i.index == EDGE_COUNT (ei_container (i)));
 648 }
 649
 650 /* Is the iterator `i' at one position before the end of the
 651    sequence?  */
 652 static inline bool
 653 ei_one_before_end_p (edge_iterator i)
 654 {
 655   return (i.index + 1 == EDGE_COUNT (ei_container (i)));
 656 }
 657
 658 /* Advance the iterator to the next element.  */
 659 static inline void
 660 ei_next (edge_iterator *i)
 661 {
 662 #ifdef ENABLE_CHECKING
 663   gcc_assert (i->index < EDGE_COUNT (ei_container (*i)));
 664 #endif
 665   i->index++;
 666 }
 667
 668 /* Move the iterator to the previous element.  */
 669 static inline void
 670 ei_prev (edge_iterator *i)
 671 {
 672 #ifdef ENABLE_CHECKING
 673   gcc_assert (i->index > 0);
 674 #endif
 675   i->index--;
 676 }
 677
 678 /* Return the edge pointed to by the iterator `i'.  */
 679 static inline edge
 680 ei_edge (edge_iterator i)
 681 {
 682   return EDGE_I (ei_container (i), i.index);
 683 }
 684
 685 /* Return an edge pointed to by the iterator.  Do it safely so that
 686    NULL is returned when the iterator is pointing at the end of the
 687    sequence.  */
 688 static inline edge
 689 ei_safe_edge (edge_iterator i)
 690 {
 691   return !ei_end_p (i) ? ei_edge (i) : NULL;
 692 }
 693
 694 /* Return 1 if we should continue to iterate.  Return 0 otherwise.
 695    *Edge P is set to the next edge if we are to continue to iterate
 696    and NULL otherwise.  */
 697
 698 static inline bool
 699 ei_cond (edge_iterator ei, edge *p)
 700 {
 701   if (!ei_end_p (ei))
 702     {
 703       *p = ei_edge (ei);
 704       return 1;
 705     }
 706   else
 707     {
 708       *p = NULL;
 709       return 0;
 710     }
 711 }
 712
 713 /* This macro serves as a convenient way to iterate each edge in a
 714    vector of predecessor or successor edges.  It must not be used when
 715    an element might be removed during the traversal, otherwise
 716    elements will be missed.  Instead, use a for-loop like that shown
 717    in the following pseudo-code:
 718
 719    FOR (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
 720      {
 721         IF (e != taken_edge)
 722           remove_edge (e);
 723         ELSE
 724           ei_next (&ei);
 725      }
 726 */
 727
 728 #define FOR_EACH_EDGE(EDGE,ITER,EDGE_VEC)       \
 729   for ((ITER) = ei_start ((EDGE_VEC));          \
 730        ei_cond ((ITER), &(EDGE));               \
 731        ei_next (&(ITER)))
 732
 733 struct edge_list * create_edge_list (void);
 734 void free_edge_list (struct edge_list *);
 735 void print_edge_list (FILE *, struct edge_list *);
 736 void verify_edge_list (FILE *, struct edge_list *);
 737 int find_edge_index (struct edge_list *, basic_block, basic_block);
 738 edge find_edge (basic_block, basic_block);
 739
 740 #define CLEANUP_EXPENSIVE       1       /* Do relatively expensive optimizations
 741                                            except for edge forwarding */
 742 #define CLEANUP_CROSSJUMP       2       /* Do crossjumping.  */
 743 #define CLEANUP_POST_REGSTACK   4       /* We run after reg-stack and need
 744                                            to care REG_DEAD notes.  */
 745 #define CLEANUP_THREADING       8       /* Do jump threading.  */
 746 #define CLEANUP_NO_INSN_DEL     16      /* Do not try to delete trivially dead
 747                                            insns.  */
 748 #define CLEANUP_CFGLAYOUT       32      /* Do cleanup in cfglayout mode.  */
 749
 750 /* In lcm.c */
 751 extern struct edge_list *pre_edge_lcm (int, sbitmap *, sbitmap *,
 752                                        sbitmap *, sbitmap *, sbitmap **,
 753                                        sbitmap **);
 754 extern struct edge_list *pre_edge_rev_lcm (int, sbitmap *,
 755                                            sbitmap *, sbitmap *,
 756                                            sbitmap *, sbitmap **,
 757                                            sbitmap **);
 758 extern void compute_available (sbitmap *, sbitmap *, sbitmap *, sbitmap *);
 759
 760 /* In predict.c */
 761 extern bool maybe_hot_bb_p (const_basic_block);
 762 extern bool maybe_hot_edge_p (edge);
 763 extern bool probably_never_executed_bb_p (const_basic_block);
 764 extern bool optimize_bb_for_size_p (const_basic_block);
 765 extern bool optimize_bb_for_speed_p (const_basic_block);
 766 extern bool optimize_edge_for_size_p (edge);
 767 extern bool optimize_edge_for_speed_p (edge);
 768 extern bool optimize_loop_for_size_p (struct loop *);
 769 extern bool optimize_loop_for_speed_p (struct loop *);
 770 extern bool optimize_loop_nest_for_size_p (struct loop *);
 771 extern bool optimize_loop_nest_for_speed_p (struct loop *);
 772 extern bool gimple_predicted_by_p (const_basic_block, enum br_predictor);
 773 extern bool rtl_predicted_by_p (const_basic_block, enum br_predictor);
 774 extern void gimple_predict_edge (edge, enum br_predictor, int);
 775 extern void rtl_predict_edge (edge, enum br_predictor, int);
 776 extern void predict_edge_def (edge, enum br_predictor, enum prediction);
 777 extern void guess_outgoing_edge_probabilities (basic_block);
 778 extern void remove_predictions_associated_with_edge (edge);
 779 extern bool edge_probability_reliable_p (const_edge);
 780 extern bool br_prob_note_reliable_p (const_rtx);
 781 extern bool predictable_edge_p (edge);
 782
 783 /* In cfg.c  */
 784 extern void init_flow (struct function *);
 785 extern void debug_bb (basic_block);
 786 extern basic_block debug_bb_n (int);
 787 extern void expunge_block (basic_block);
 788 extern void link_block (basic_block, basic_block);
 789 extern void unlink_block (basic_block);
 790 extern void compact_blocks (void);
 791 extern basic_block alloc_block (void);
 792 extern void alloc_aux_for_blocks (int);
 793 extern void clear_aux_for_blocks (void);
 794 extern void free_aux_for_blocks (void);
 795 extern void alloc_aux_for_edges (int);
 796 extern void clear_aux_for_edges (void);
 797 extern void free_aux_for_edges (void);
 798
 799 /* In cfganal.c  */
 800 extern void find_unreachable_blocks (void);
 801 extern bool forwarder_block_p (const_basic_block);
 802 extern bool can_fallthru (basic_block, basic_block);
 803 extern bool could_fall_through (basic_block, basic_block);
 804 extern void flow_nodes_print (const char *, const_sbitmap, FILE *);
 805 extern void flow_edge_list_print (const char *, const edge *, int, FILE *);
 806
 807 /* In cfgrtl.c  */
 808 extern basic_block force_nonfallthru (edge);
 809 extern rtx block_label (basic_block);
 810 extern bool purge_all_dead_edges (void);
 811 extern bool purge_dead_edges (basic_block);
 812
 813 /* In cfgbuild.c.  */
 814 extern void find_many_sub_basic_blocks (sbitmap);
 815 extern void rtl_make_eh_edge (sbitmap, basic_block, rtx);
 816
 817 /* In cfgcleanup.c.  */
 818 extern bool cleanup_cfg (int);
 819 extern int flow_find_cross_jump (basic_block, basic_block, rtx *, rtx *);
 820 extern int flow_find_head_matching_sequence (basic_block, basic_block,
 821                                              rtx *, rtx *, int);
 822
 823 extern bool delete_unreachable_blocks (void);
 824
 825 extern bool mark_dfs_back_edges (void);
 826 extern void set_edge_can_fallthru_flag (void);
 827 extern void update_br_prob_note (basic_block);
 828 extern void fixup_abnormal_edges (void);
 829 extern bool inside_basic_block_p (const_rtx);
 830 extern bool control_flow_insn_p (const_rtx);
 831 extern rtx get_last_bb_insn (basic_block);
 832
 833 /* In bb-reorder.c */
 834 extern void reorder_basic_blocks (void);
 835
 836 /* In dominance.c */
 837
 838 enum cdi_direction
 839 {
 840   CDI_DOMINATORS = 1,
 841   CDI_POST_DOMINATORS = 2
 842 };
 843
 844 extern enum dom_state dom_info_state (enum cdi_direction);
 845 extern void set_dom_info_availability (enum cdi_direction, enum dom_state);
 846 extern bool dom_info_available_p (enum cdi_direction);
 847 extern void calculate_dominance_info (enum cdi_direction);
 848 extern void free_dominance_info (enum cdi_direction);
 849 extern basic_block nearest_common_dominator (enum cdi_direction,
 850                                              basic_block, basic_block);
 851 extern basic_block nearest_common_dominator_for_set (enum cdi_direction,
 852                                                      bitmap);
 853 extern void set_immediate_dominator (enum cdi_direction, basic_block,
 854                                      basic_block);
 855 extern basic_block get_immediate_dominator (enum cdi_direction, basic_block);
 856 extern bool dominated_by_p (enum cdi_direction, const_basic_block, const_basic_block);
 857 extern VEC (basic_block, heap) *get_dominated_by (enum cdi_direction, basic_block);
 858 extern VEC (basic_block, heap) *get_dominated_by_region (enum cdi_direction,
 859                                                          basic_block *,
 860                                                          unsigned);
 861 extern VEC (basic_block, heap) *get_dominated_to_depth (enum cdi_direction,
 862                                                         basic_block, int);
 863 extern VEC (basic_block, heap) *get_all_dominated_blocks (enum cdi_direction,
 864                                                           basic_block);
 865 extern void add_to_dominance_info (enum cdi_direction, basic_block);
 866 extern void delete_from_dominance_info (enum cdi_direction, basic_block);
 867 basic_block recompute_dominator (enum cdi_direction, basic_block);
 868 extern void redirect_immediate_dominators (enum cdi_direction, basic_block,
 869                                            basic_block);
 870 extern void iterate_fix_dominators (enum cdi_direction,
 871                                     VEC (basic_block, heap) *, bool);
 872 extern void verify_dominators (enum cdi_direction);
 873 extern basic_block first_dom_son (enum cdi_direction, basic_block);
 874 extern basic_block next_dom_son (enum cdi_direction, basic_block);
 875 unsigned bb_dom_dfs_in (enum cdi_direction, basic_block);
 876 unsigned bb_dom_dfs_out (enum cdi_direction, basic_block);
 877
 878 extern edge try_redirect_by_replacing_jump (edge, basic_block, bool);
 879 extern void break_superblocks (void);
 880 extern void relink_block_chain (bool);
 881 extern void check_bb_profile (basic_block, FILE *);
 882 extern void update_bb_profile_for_threading (basic_block, int, gcov_type, edge);
 883 extern void init_rtl_bb_info (basic_block);
 884
 885 extern void initialize_original_copy_tables (void);
 886 extern void free_original_copy_tables (void);
 887 extern void set_bb_original (basic_block, basic_block);
 888 extern basic_block get_bb_original (basic_block);
 889 extern void set_bb_copy (basic_block, basic_block);
 890 extern basic_block get_bb_copy (basic_block);
 891 void set_loop_copy (struct loop *, struct loop *);
 892 struct loop *get_loop_copy (struct loop *);
 893
 894
 895 extern rtx insert_insn_end_bb_new (rtx, basic_block);
 896
 897 #include "cfghooks.h"
 898
 899 /* Return true when one of the predecessor edges of BB is marked with EDGE_EH.  */
 900 static inline bool
 901 bb_has_eh_pred (basic_block bb)
 902 {
 903   edge e;
 904   edge_iterator ei;
 905
 906   FOR_EACH_EDGE (e, ei, bb->preds)
 907     {
 908       if (e->flags & EDGE_EH)
 909         return true;
 910     }
 911   return false;
 912 }
 913
 914 /* Return true when one of the predecessor edges of BB is marked with EDGE_ABNORMAL.  */
 915 static inline bool
 916 bb_has_abnormal_pred (basic_block bb)
 917 {
 918   edge e;
 919   edge_iterator ei;
 920
 921   FOR_EACH_EDGE (e, ei, bb->preds)
 922     {
 923       if (e->flags & EDGE_ABNORMAL)
 924         return true;
 925     }
 926   return false;
 927 }
 928
 929 /* Return the fallthru edge in EDGES if it exists, NULL otherwise.  */
 930 static inline edge
 931 find_fallthru_edge (VEC(edge,gc) *edges)
 932 {
 933   edge e;
 934   edge_iterator ei;
 935
 936   FOR_EACH_EDGE (e, ei, edges)
 937     if (e->flags & EDGE_FALLTHRU)
 938       break;
 939
 940   return e;
 941 }
 942
 943 /* In cfgloopmanip.c.  */
 944 extern edge mfb_kj_edge;
 945 extern bool mfb_keep_just (edge);
 946
 947 /* In cfgexpand.c.  */
 948 extern void rtl_profile_for_bb (basic_block);
 949 extern void rtl_profile_for_edge (edge);
 950 extern void default_rtl_profile (void);
 951
 952 #endif /* GCC_BASIC_BLOCK_H */