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   basic_block src;
  39   basic_block 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 cfg-flags.def */
  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 /* Masks for edge.flags.  */
  69 #define DEF_EDGE_FLAG(NAME,IDX) EDGE_##NAME = 1 << IDX ,
  70 enum cfg_edge_flags {
  71 #include "cfg-flags.def"
  72   LAST_CFG_EDGE_FLAG            /* this is only used for EDGE_ALL_FLAGS */
  73 };
  74 #undef DEF_EDGE_FLAG
  75
  76 /* Bit mask for all edge flags.  */
  77 #define EDGE_ALL_FLAGS          ((LAST_CFG_EDGE_FLAG - 1) * 2 - 1)
  78
  79 /* The following four flags all indicate something special about an edge.
  80    Test the edge flags on EDGE_COMPLEX to detect all forms of "strange"
  81    control flow transfers.  */
  82 #define EDGE_COMPLEX \
  83   (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH | EDGE_PRESERVE)
  84
  85 /* Counter summary from the last set of coverage counts read by
  86    profile.c.  */
  87 extern const struct gcov_ctr_summary *profile_info;
  88
  89 /* Declared in cfgloop.h.  */
  90 struct loop;
  91
  92 struct GTY(()) rtl_bb_info {
  93   /* The first insn of the block is embedded into bb->il.x.  */
  94   /* The last insn of the block.  */
  95   rtx end_;
  96
  97   /* In CFGlayout mode points to insn notes/jumptables to be placed just before
  98      and after the block.   */
  99   rtx header_;
 100   rtx footer_;
 101 };
 102
 103 struct GTY(()) gimple_bb_info {
 104   /* Sequence of statements in this block.  */
 105   gimple_seq seq;
 106
 107   /* PHI nodes for this block.  */
 108   gimple_seq phi_nodes;
 109 };
 110
 111 /* A basic block is a sequence of instructions with only entry and
 112    only one exit.  If any one of the instructions are executed, they
 113    will all be executed, and in sequence from first to last.
 114
 115    There may be COND_EXEC instructions in the basic block.  The
 116    COND_EXEC *instructions* will be executed -- but if the condition
 117    is false the conditionally executed *expressions* will of course
 118    not be executed.  We don't consider the conditionally executed
 119    expression (which might have side-effects) to be in a separate
 120    basic block because the program counter will always be at the same
 121    location after the COND_EXEC instruction, regardless of whether the
 122    condition is true or not.
 123
 124    Basic blocks need not start with a label nor end with a jump insn.
 125    For example, a previous basic block may just "conditionally fall"
 126    into the succeeding basic block, and the last basic block need not
 127    end with a jump insn.  Block 0 is a descendant of the entry block.
 128
 129    A basic block beginning with two labels cannot have notes between
 130    the labels.
 131
 132    Data for jump tables are stored in jump_insns that occur in no
 133    basic block even though these insns can follow or precede insns in
 134    basic blocks.  */
 135
 136 /* Basic block information indexed by block number.  */
 137 struct GTY((chain_next ("%h.next_bb"), chain_prev ("%h.prev_bb"))) basic_block_def {
 138   /* The edges into and out of the block.  */
 139   VEC(edge,gc) *preds;
 140   VEC(edge,gc) *succs;
 141
 142   /* Auxiliary info specific to a pass.  */
 143   PTR GTY ((skip (""))) aux;
 144
 145   /* Innermost loop containing the block.  */
 146   struct loop *loop_father;
 147
 148   /* The dominance and postdominance information node.  */
 149   struct et_node * GTY ((skip (""))) dom[2];
 150
 151   /* Previous and next blocks in the chain.  */
 152   basic_block prev_bb;
 153   basic_block next_bb;
 154
 155   union basic_block_il_dependent {
 156       struct gimple_bb_info GTY ((tag ("0"))) gimple;
 157       struct {
 158         rtx head_;
 159         struct rtl_bb_info * rtl;
 160       } GTY ((tag ("1"))) x;
 161     } GTY ((desc ("((%1.flags & BB_RTL) != 0)"))) il;
 162
 163   /* Expected number of executions: calculated in profile.c.  */
 164   gcov_type count;
 165
 166   /* The index of this block.  */
 167   int index;
 168
 169   /* The loop depth of this block.  */
 170   int loop_depth;
 171
 172   /* Expected frequency.  Normalized to be in range 0 to BB_FREQ_MAX.  */
 173   int frequency;
 174
 175   /* The discriminator for this block.  The discriminator distinguishes
 176      among several basic blocks that share a common locus, allowing for
 177      more accurate sample-based profiling.  */
 178   int discriminator;
 179
 180   /* Various flags.  See cfg-flags.def.  */
 181   int flags;
 182 };
 183
 184 /* This ensures that struct gimple_bb_info is smaller than
 185    struct rtl_bb_info, so that inlining the former into basic_block_def
 186    is the better choice.  */
 187 typedef int __assert_gimple_bb_smaller_rtl_bb
 188               [(int)sizeof(struct rtl_bb_info)
 189                - (int)sizeof (struct gimple_bb_info)];
 190
 191 DEF_VEC_P(basic_block);
 192 DEF_VEC_ALLOC_P(basic_block,gc);
 193 DEF_VEC_ALLOC_P(basic_block,heap);
 194
 195 #define BB_FREQ_MAX 10000
 196
 197 /* Masks for basic_block.flags.  */
 198 #define DEF_BASIC_BLOCK_FLAG(NAME,IDX) BB_##NAME = 1 << IDX ,
 199 enum cfg_bb_flags
 200 {
 201 #include "cfg-flags.def"
 202   LAST_CFG_BB_FLAG              /* this is only used for BB_ALL_FLAGS */
 203 };
 204 #undef DEF_BASIC_BLOCK_FLAG
 205
 206 /* Bit mask for all basic block flags.  */
 207 #define BB_ALL_FLAGS            ((LAST_CFG_BB_FLAG - 1) * 2 - 1)
 208
 209 /* Bit mask for all basic block flags that must be preserved.  These are
 210    the bit masks that are *not* cleared by clear_bb_flags.  */
 211 #define BB_FLAGS_TO_PRESERVE                                    \
 212   (BB_DISABLE_SCHEDULE | BB_RTL | BB_NON_LOCAL_GOTO_TARGET      \
 213    | BB_HOT_PARTITION | BB_COLD_PARTITION)
 214
 215 /* Dummy bitmask for convenience in the hot/cold partitioning code.  */
 216 #define BB_UNPARTITIONED        0
 217
 218 /* Partitions, to be used when partitioning hot and cold basic blocks into
 219    separate sections.  */
 220 #define BB_PARTITION(bb) ((bb)->flags & (BB_HOT_PARTITION|BB_COLD_PARTITION))
 221 #define BB_SET_PARTITION(bb, part) do {                                 \
 222   basic_block bb_ = (bb);                                               \
 223   bb_->flags = ((bb_->flags & ~(BB_HOT_PARTITION|BB_COLD_PARTITION))    \
 224                 | (part));                                              \
 225 } while (0)
 226
 227 #define BB_COPY_PARTITION(dstbb, srcbb) \
 228   BB_SET_PARTITION (dstbb, BB_PARTITION (srcbb))
 229
 230 /* State of dominance information.  */
 231
 232 enum dom_state
 233 {
 234   DOM_NONE,             /* Not computed at all.  */
 235   DOM_NO_FAST_QUERY,    /* The data is OK, but the fast query data are not usable.  */
 236   DOM_OK                /* Everything is ok.  */
 237 };
 238
 239 /* What sort of profiling information we have.  */
 240 enum profile_status_d
 241 {
 242   PROFILE_ABSENT,
 243   PROFILE_GUESSED,
 244   PROFILE_READ,
 245   PROFILE_LAST  /* Last value, used by profile streaming.  */
 246 };
 247
 248 /* A structure to group all the per-function control flow graph data.
 249    The x_* prefixing is necessary because otherwise references to the
 250    fields of this struct are interpreted as the defines for backward
 251    source compatibility following the definition of this struct.  */
 252 struct GTY(()) control_flow_graph {
 253   /* Block pointers for the exit and entry of a function.
 254      These are always the head and tail of the basic block list.  */
 255   basic_block x_entry_block_ptr;
 256   basic_block x_exit_block_ptr;
 257
 258   /* Index by basic block number, get basic block struct info.  */
 259   VEC(basic_block,gc) *x_basic_block_info;
 260
 261   /* Number of basic blocks in this flow graph.  */
 262   int x_n_basic_blocks;
 263
 264   /* Number of edges in this flow graph.  */
 265   int x_n_edges;
 266
 267   /* The first free basic block number.  */
 268   int x_last_basic_block;
 269
 270   /* UIDs for LABEL_DECLs.  */
 271   int last_label_uid;
 272
 273   /* Mapping of labels to their associated blocks.  At present
 274      only used for the gimple CFG.  */
 275   VEC(basic_block,gc) *x_label_to_block_map;
 276
 277   enum profile_status_d x_profile_status;
 278
 279   /* Whether the dominators and the postdominators are available.  */
 280   enum dom_state x_dom_computed[2];
 281
 282   /* Number of basic blocks in the dominance tree.  */
 283   unsigned x_n_bbs_in_dom_tree[2];
 284
 285   /* Maximal number of entities in the single jumptable.  Used to estimate
 286      final flowgraph size.  */
 287   int max_jumptable_ents;
 288 };
 289
 290 /* Defines for accessing the fields of the CFG structure for function FN.  */
 291 #define ENTRY_BLOCK_PTR_FOR_FUNCTION(FN)     ((FN)->cfg->x_entry_block_ptr)
 292 #define EXIT_BLOCK_PTR_FOR_FUNCTION(FN)      ((FN)->cfg->x_exit_block_ptr)
 293 #define basic_block_info_for_function(FN)    ((FN)->cfg->x_basic_block_info)
 294 #define n_basic_blocks_for_function(FN)      ((FN)->cfg->x_n_basic_blocks)
 295 #define n_edges_for_function(FN)             ((FN)->cfg->x_n_edges)
 296 #define last_basic_block_for_function(FN)    ((FN)->cfg->x_last_basic_block)
 297 #define label_to_block_map_for_function(FN)  ((FN)->cfg->x_label_to_block_map)
 298 #define profile_status_for_function(FN)      ((FN)->cfg->x_profile_status)
 299
 300 #define BASIC_BLOCK_FOR_FUNCTION(FN,N) \
 301   (VEC_index (basic_block, basic_block_info_for_function(FN), (N)))
 302 #define SET_BASIC_BLOCK_FOR_FUNCTION(FN,N,BB) \
 303   (VEC_replace (basic_block, basic_block_info_for_function(FN), (N), (BB)))
 304
 305 /* Defines for textual backward source compatibility.  */
 306 #define ENTRY_BLOCK_PTR         (cfun->cfg->x_entry_block_ptr)
 307 #define EXIT_BLOCK_PTR          (cfun->cfg->x_exit_block_ptr)
 308 #define basic_block_info        (cfun->cfg->x_basic_block_info)
 309 #define n_basic_blocks          (cfun->cfg->x_n_basic_blocks)
 310 #define n_edges                 (cfun->cfg->x_n_edges)
 311 #define last_basic_block        (cfun->cfg->x_last_basic_block)
 312 #define label_to_block_map      (cfun->cfg->x_label_to_block_map)
 313 #define profile_status          (cfun->cfg->x_profile_status)
 314
 315 #define BASIC_BLOCK(N)          (VEC_index (basic_block, basic_block_info, (N)))
 316 #define SET_BASIC_BLOCK(N,BB)   (VEC_replace (basic_block, basic_block_info, (N), (BB)))
 317
 318 /* For iterating over basic blocks.  */
 319 #define FOR_BB_BETWEEN(BB, FROM, TO, DIR) \
 320   for (BB = FROM; BB != TO; BB = BB->DIR)
 321
 322 #define FOR_EACH_BB_FN(BB, FN) \
 323   FOR_BB_BETWEEN (BB, (FN)->cfg->x_entry_block_ptr->next_bb, (FN)->cfg->x_exit_block_ptr, next_bb)
 324
 325 #define FOR_EACH_BB(BB) FOR_EACH_BB_FN (BB, cfun)
 326
 327 #define FOR_EACH_BB_REVERSE_FN(BB, FN) \
 328   FOR_BB_BETWEEN (BB, (FN)->cfg->x_exit_block_ptr->prev_bb, (FN)->cfg->x_entry_block_ptr, prev_bb)
 329
 330 #define FOR_EACH_BB_REVERSE(BB) FOR_EACH_BB_REVERSE_FN(BB, cfun)
 331
 332 /* For iterating over insns in basic block.  */
 333 #define FOR_BB_INSNS(BB, INSN)                  \
 334   for ((INSN) = BB_HEAD (BB);                   \
 335        (INSN) && (INSN) != NEXT_INSN (BB_END (BB));     \
 336        (INSN) = NEXT_INSN (INSN))
 337
 338 /* For iterating over insns in basic block when we might remove the
 339    current insn.  */
 340 #define FOR_BB_INSNS_SAFE(BB, INSN, CURR)                       \
 341   for ((INSN) = BB_HEAD (BB), (CURR) = (INSN) ? NEXT_INSN ((INSN)): NULL;       \
 342        (INSN) && (INSN) != NEXT_INSN (BB_END (BB));     \
 343        (INSN) = (CURR), (CURR) = (INSN) ? NEXT_INSN ((INSN)) : NULL)
 344
 345 #define FOR_BB_INSNS_REVERSE(BB, INSN)          \
 346   for ((INSN) = BB_END (BB);                    \
 347        (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));    \
 348        (INSN) = PREV_INSN (INSN))
 349
 350 #define FOR_BB_INSNS_REVERSE_SAFE(BB, INSN, CURR)       \
 351   for ((INSN) = BB_END (BB),(CURR) = (INSN) ? PREV_INSN ((INSN)) : NULL;        \
 352        (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));    \
 353        (INSN) = (CURR), (CURR) = (INSN) ? PREV_INSN ((INSN)) : NULL)
 354
 355 /* Cycles through _all_ basic blocks, even the fake ones (entry and
 356    exit block).  */
 357
 358 #define FOR_ALL_BB(BB) \
 359   for (BB = ENTRY_BLOCK_PTR; BB; BB = BB->next_bb)
 360
 361 #define FOR_ALL_BB_FN(BB, FN) \
 362   for (BB = ENTRY_BLOCK_PTR_FOR_FUNCTION (FN); BB; BB = BB->next_bb)
 363
 364 \f
 365 /* Stuff for recording basic block info.  */
 366
 367 #define BB_HEAD(B)      (B)->il.x.head_
 368 #define BB_END(B)       (B)->il.x.rtl->end_
 369 #define BB_HEADER(B)    (B)->il.x.rtl->header_
 370 #define BB_FOOTER(B)    (B)->il.x.rtl->footer_
 371
 372 /* Special block numbers [markers] for entry and exit.
 373    Neither of them is supposed to hold actual statements.  */
 374 #define ENTRY_BLOCK (0)
 375 #define EXIT_BLOCK (1)
 376
 377 /* The two blocks that are always in the cfg.  */
 378 #define NUM_FIXED_BLOCKS (2)
 379
 380 #define set_block_for_insn(INSN, BB)  (BLOCK_FOR_INSN (INSN) = BB)
 381
 382 extern void compute_bb_for_insn (void);
 383 extern unsigned int free_bb_for_insn (void);
 384 extern void update_bb_for_insn (basic_block);
 385
 386 extern void insert_insn_on_edge (rtx, edge);
 387 basic_block split_edge_and_insert (edge, rtx);
 388
 389 extern void commit_one_edge_insertion (edge e);
 390 extern void commit_edge_insertions (void);
 391
 392 extern edge unchecked_make_edge (basic_block, basic_block, int);
 393 extern edge cached_make_edge (sbitmap, basic_block, basic_block, int);
 394 extern edge make_edge (basic_block, basic_block, int);
 395 extern edge make_single_succ_edge (basic_block, basic_block, int);
 396 extern void remove_edge_raw (edge);
 397 extern void redirect_edge_succ (edge, basic_block);
 398 extern edge redirect_edge_succ_nodup (edge, basic_block);
 399 extern void redirect_edge_pred (edge, basic_block);
 400 extern basic_block create_basic_block_structure (rtx, rtx, rtx, basic_block);
 401 extern void clear_bb_flags (void);
 402 extern void dump_bb_info (FILE *, basic_block, int, int, bool, bool);
 403 extern void dump_edge_info (FILE *, edge, int, int);
 404 extern void brief_dump_cfg (FILE *, int);
 405 extern void clear_edges (void);
 406 extern void scale_bbs_frequencies_int (basic_block *, int, int, int);
 407 extern void scale_bbs_frequencies_gcov_type (basic_block *, int, gcov_type,
 408                                              gcov_type);
 409
 410 /* Structure to group all of the information to process IF-THEN and
 411    IF-THEN-ELSE blocks for the conditional execution support.  This
 412    needs to be in a public file in case the IFCVT macros call
 413    functions passing the ce_if_block data structure.  */
 414
 415 typedef struct ce_if_block
 416 {
 417   basic_block test_bb;                  /* First test block.  */
 418   basic_block then_bb;                  /* THEN block.  */
 419   basic_block else_bb;                  /* ELSE block or NULL.  */
 420   basic_block join_bb;                  /* Join THEN/ELSE blocks.  */
 421   basic_block last_test_bb;             /* Last bb to hold && or || tests.  */
 422   int num_multiple_test_blocks;         /* # of && and || basic blocks.  */
 423   int num_and_and_blocks;               /* # of && blocks.  */
 424   int num_or_or_blocks;                 /* # of || blocks.  */
 425   int num_multiple_test_insns;          /* # of insns in && and || blocks.  */
 426   int and_and_p;                        /* Complex test is &&.  */
 427   int num_then_insns;                   /* # of insns in THEN block.  */
 428   int num_else_insns;                   /* # of insns in ELSE block.  */
 429   int pass;                             /* Pass number.  */
 430 } ce_if_block_t;
 431
 432 /* This structure maintains an edge list vector.  */
 433 /* FIXME: Make this a VEC(edge).  */
 434 struct edge_list
 435 {
 436   int num_edges;
 437   edge *index_to_edge;
 438 };
 439
 440 /* The base value for branch probability notes and edge probabilities.  */
 441 #define REG_BR_PROB_BASE  10000
 442
 443 /* This is the value which indicates no edge is present.  */
 444 #define EDGE_INDEX_NO_EDGE      -1
 445
 446 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 447    if there is no edge between the 2 basic blocks.  */
 448 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 449
 450 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 451    block which is either the pred or succ end of the indexed edge.  */
 452 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 453 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 454
 455 /* INDEX_EDGE returns a pointer to the edge.  */
 456 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 457
 458 /* Number of edges in the compressed edge list.  */
 459 #define NUM_EDGES(el)                   ((el)->num_edges)
 460
 461 /* BB is assumed to contain conditional jump.  Return the fallthru edge.  */
 462 #define FALLTHRU_EDGE(bb)               (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
 463                                          ? EDGE_SUCC ((bb), 0) : EDGE_SUCC ((bb), 1))
 464
 465 /* BB is assumed to contain conditional jump.  Return the branch edge.  */
 466 #define BRANCH_EDGE(bb)                 (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
 467                                          ? EDGE_SUCC ((bb), 1) : EDGE_SUCC ((bb), 0))
 468
 469 /* Return expected execution frequency of the edge E.  */
 470 #define EDGE_FREQUENCY(e)               (((e)->src->frequency \
 471                                           * (e)->probability \
 472                                           + REG_BR_PROB_BASE / 2) \
 473                                          / REG_BR_PROB_BASE)
 474
 475 /* Return nonzero if edge is critical.  */
 476 #define EDGE_CRITICAL_P(e)              (EDGE_COUNT ((e)->src->succs) >= 2 \
 477                                          && EDGE_COUNT ((e)->dest->preds) >= 2)
 478
 479 #define EDGE_COUNT(ev)                  VEC_length (edge, (ev))
 480 #define EDGE_I(ev,i)                    VEC_index  (edge, (ev), (i))
 481 #define EDGE_PRED(bb,i)                 VEC_index  (edge, (bb)->preds, (i))
 482 #define EDGE_SUCC(bb,i)                 VEC_index  (edge, (bb)->succs, (i))
 483
 484 /* Returns true if BB has precisely one successor.  */
 485
 486 static inline bool
 487 single_succ_p (const_basic_block bb)
 488 {
 489   return EDGE_COUNT (bb->succs) == 1;
 490 }
 491
 492 /* Returns true if BB has precisely one predecessor.  */
 493
 494 static inline bool
 495 single_pred_p (const_basic_block bb)
 496 {
 497   return EDGE_COUNT (bb->preds) == 1;
 498 }
 499
 500 /* Returns the single successor edge of basic block BB.  Aborts if
 501    BB does not have exactly one successor.  */
 502
 503 static inline edge
 504 single_succ_edge (const_basic_block bb)
 505 {
 506   gcc_checking_assert (single_succ_p (bb));
 507   return EDGE_SUCC (bb, 0);
 508 }
 509
 510 /* Returns the single predecessor edge of basic block BB.  Aborts
 511    if BB does not have exactly one predecessor.  */
 512
 513 static inline edge
 514 single_pred_edge (const_basic_block bb)
 515 {
 516   gcc_checking_assert (single_pred_p (bb));
 517   return EDGE_PRED (bb, 0);
 518 }
 519
 520 /* Returns the single successor block of basic block BB.  Aborts
 521    if BB does not have exactly one successor.  */
 522
 523 static inline basic_block
 524 single_succ (const_basic_block bb)
 525 {
 526   return single_succ_edge (bb)->dest;
 527 }
 528
 529 /* Returns the single predecessor block of basic block BB.  Aborts
 530    if BB does not have exactly one predecessor.*/
 531
 532 static inline basic_block
 533 single_pred (const_basic_block bb)
 534 {
 535   return single_pred_edge (bb)->src;
 536 }
 537
 538 /* Iterator object for edges.  */
 539
 540 typedef struct {
 541   unsigned index;
 542   VEC(edge,gc) **container;
 543 } edge_iterator;
 544
 545 static inline VEC(edge,gc) *
 546 ei_container (edge_iterator i)
 547 {
 548   gcc_checking_assert (i.container);
 549   return *i.container;
 550 }
 551
 552 #define ei_start(iter) ei_start_1 (&(iter))
 553 #define ei_last(iter) ei_last_1 (&(iter))
 554
 555 /* Return an iterator pointing to the start of an edge vector.  */
 556 static inline edge_iterator
 557 ei_start_1 (VEC(edge,gc) **ev)
 558 {
 559   edge_iterator i;
 560
 561   i.index = 0;
 562   i.container = ev;
 563
 564   return i;
 565 }
 566
 567 /* Return an iterator pointing to the last element of an edge
 568    vector.  */
 569 static inline edge_iterator
 570 ei_last_1 (VEC(edge,gc) **ev)
 571 {
 572   edge_iterator i;
 573
 574   i.index = EDGE_COUNT (*ev) - 1;
 575   i.container = ev;
 576
 577   return i;
 578 }
 579
 580 /* Is the iterator `i' at the end of the sequence?  */
 581 static inline bool
 582 ei_end_p (edge_iterator i)
 583 {
 584   return (i.index == EDGE_COUNT (ei_container (i)));
 585 }
 586
 587 /* Is the iterator `i' at one position before the end of the
 588    sequence?  */
 589 static inline bool
 590 ei_one_before_end_p (edge_iterator i)
 591 {
 592   return (i.index + 1 == EDGE_COUNT (ei_container (i)));
 593 }
 594
 595 /* Advance the iterator to the next element.  */
 596 static inline void
 597 ei_next (edge_iterator *i)
 598 {
 599   gcc_checking_assert (i->index < EDGE_COUNT (ei_container (*i)));
 600   i->index++;
 601 }
 602
 603 /* Move the iterator to the previous element.  */
 604 static inline void
 605 ei_prev (edge_iterator *i)
 606 {
 607   gcc_checking_assert (i->index > 0);
 608   i->index--;
 609 }
 610
 611 /* Return the edge pointed to by the iterator `i'.  */
 612 static inline edge
 613 ei_edge (edge_iterator i)
 614 {
 615   return EDGE_I (ei_container (i), i.index);
 616 }
 617
 618 /* Return an edge pointed to by the iterator.  Do it safely so that
 619    NULL is returned when the iterator is pointing at the end of the
 620    sequence.  */
 621 static inline edge
 622 ei_safe_edge (edge_iterator i)
 623 {
 624   return !ei_end_p (i) ? ei_edge (i) : NULL;
 625 }
 626
 627 /* Return 1 if we should continue to iterate.  Return 0 otherwise.
 628    *Edge P is set to the next edge if we are to continue to iterate
 629    and NULL otherwise.  */
 630
 631 static inline bool
 632 ei_cond (edge_iterator ei, edge *p)
 633 {
 634   if (!ei_end_p (ei))
 635     {
 636       *p = ei_edge (ei);
 637       return 1;
 638     }
 639   else
 640     {
 641       *p = NULL;
 642       return 0;
 643     }
 644 }
 645
 646 /* This macro serves as a convenient way to iterate each edge in a
 647    vector of predecessor or successor edges.  It must not be used when
 648    an element might be removed during the traversal, otherwise
 649    elements will be missed.  Instead, use a for-loop like that shown
 650    in the following pseudo-code:
 651
 652    FOR (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
 653      {
 654         IF (e != taken_edge)
 655           remove_edge (e);
 656         ELSE
 657           ei_next (&ei);
 658      }
 659 */
 660
 661 #define FOR_EACH_EDGE(EDGE,ITER,EDGE_VEC)       \
 662   for ((ITER) = ei_start ((EDGE_VEC));          \
 663        ei_cond ((ITER), &(EDGE));               \
 664        ei_next (&(ITER)))
 665
 666 #define CLEANUP_EXPENSIVE       1       /* Do relatively expensive optimizations
 667                                            except for edge forwarding */
 668 #define CLEANUP_CROSSJUMP       2       /* Do crossjumping.  */
 669 #define CLEANUP_POST_REGSTACK   4       /* We run after reg-stack and need
 670                                            to care REG_DEAD notes.  */
 671 #define CLEANUP_THREADING       8       /* Do jump threading.  */
 672 #define CLEANUP_NO_INSN_DEL     16      /* Do not try to delete trivially dead
 673                                            insns.  */
 674 #define CLEANUP_CFGLAYOUT       32      /* Do cleanup in cfglayout mode.  */
 675 #define CLEANUP_CFG_CHANGED     64      /* The caller changed the CFG.  */
 676
 677 /* In lcm.c */
 678 extern struct edge_list *pre_edge_lcm (int, sbitmap *, sbitmap *,
 679                                        sbitmap *, sbitmap *, sbitmap **,
 680                                        sbitmap **);
 681 extern struct edge_list *pre_edge_rev_lcm (int, sbitmap *,
 682                                            sbitmap *, sbitmap *,
 683                                            sbitmap *, sbitmap **,
 684                                            sbitmap **);
 685 extern void compute_available (sbitmap *, sbitmap *, sbitmap *, sbitmap *);
 686
 687 /* In predict.c */
 688 extern bool maybe_hot_bb_p (const_basic_block);
 689 extern bool maybe_hot_edge_p (edge);
 690 extern bool probably_never_executed_bb_p (const_basic_block);
 691 extern bool optimize_bb_for_size_p (const_basic_block);
 692 extern bool optimize_bb_for_speed_p (const_basic_block);
 693 extern bool optimize_edge_for_size_p (edge);
 694 extern bool optimize_edge_for_speed_p (edge);
 695 extern bool optimize_loop_for_size_p (struct loop *);
 696 extern bool optimize_loop_for_speed_p (struct loop *);
 697 extern bool optimize_loop_nest_for_size_p (struct loop *);
 698 extern bool optimize_loop_nest_for_speed_p (struct loop *);
 699 extern bool gimple_predicted_by_p (const_basic_block, enum br_predictor);
 700 extern bool rtl_predicted_by_p (const_basic_block, enum br_predictor);
 701 extern void gimple_predict_edge (edge, enum br_predictor, int);
 702 extern void rtl_predict_edge (edge, enum br_predictor, int);
 703 extern void predict_edge_def (edge, enum br_predictor, enum prediction);
 704 extern void guess_outgoing_edge_probabilities (basic_block);
 705 extern void remove_predictions_associated_with_edge (edge);
 706 extern bool edge_probability_reliable_p (const_edge);
 707 extern bool br_prob_note_reliable_p (const_rtx);
 708 extern bool predictable_edge_p (edge);
 709
 710 /* In cfg.c  */
 711 extern void init_flow (struct function *);
 712 extern void debug_bb (basic_block);
 713 extern basic_block debug_bb_n (int);
 714 extern void dump_flow_info (FILE *, int);
 715 extern void expunge_block (basic_block);
 716 extern void link_block (basic_block, basic_block);
 717 extern void unlink_block (basic_block);
 718 extern void compact_blocks (void);
 719 extern basic_block alloc_block (void);
 720 extern void alloc_aux_for_blocks (int);
 721 extern void clear_aux_for_blocks (void);
 722 extern void free_aux_for_blocks (void);
 723 extern void alloc_aux_for_edge (edge, int);
 724 extern void alloc_aux_for_edges (int);
 725 extern void clear_aux_for_edges (void);
 726 extern void free_aux_for_edges (void);
 727
 728 /* In cfganal.c  */
 729 extern void find_unreachable_blocks (void);
 730 extern bool mark_dfs_back_edges (void);
 731 struct edge_list * create_edge_list (void);
 732 void free_edge_list (struct edge_list *);
 733 void print_edge_list (FILE *, struct edge_list *);
 734 void verify_edge_list (FILE *, struct edge_list *);
 735 int find_edge_index (struct edge_list *, basic_block, basic_block);
 736 edge find_edge (basic_block, basic_block);
 737 extern void remove_fake_edges (void);
 738 extern void remove_fake_exit_edges (void);
 739 extern void add_noreturn_fake_exit_edges (void);
 740 extern void connect_infinite_loops_to_exit (void);
 741 extern int post_order_compute (int *, bool, bool);
 742 extern int inverted_post_order_compute (int *);
 743 extern int pre_and_rev_post_order_compute (int *, int *, bool);
 744 extern int dfs_enumerate_from (basic_block, int,
 745                                bool (*)(const_basic_block, const void *),
 746                                basic_block *, int, const void *);
 747 extern void compute_dominance_frontiers (struct bitmap_head_def *);
 748 extern bitmap compute_idf (bitmap, struct bitmap_head_def *);
 749
 750 /* In cfgrtl.c  */
 751 extern rtx block_label (basic_block);
 752 extern rtx bb_note (basic_block);
 753 extern bool purge_all_dead_edges (void);
 754 extern bool purge_dead_edges (basic_block);
 755 extern bool fixup_abnormal_edges (void);
 756 extern basic_block force_nonfallthru_and_redirect (edge, basic_block, rtx);
 757 extern bool forwarder_block_p (const_basic_block);
 758 extern bool can_fallthru (basic_block, basic_block);
 759
 760 /* In cfgbuild.c.  */
 761 extern void find_many_sub_basic_blocks (sbitmap);
 762 extern void rtl_make_eh_edge (sbitmap, basic_block, rtx);
 763
 764 enum replace_direction { dir_none, dir_forward, dir_backward, dir_both };
 765
 766 /* In cfgcleanup.c.  */
 767 extern bool cleanup_cfg (int);
 768 extern int flow_find_cross_jump (basic_block, basic_block, rtx *, rtx *,
 769                                  enum replace_direction*);
 770 extern int flow_find_head_matching_sequence (basic_block, basic_block,
 771                                              rtx *, rtx *, int);
 772
 773 extern bool delete_unreachable_blocks (void);
 774
 775 extern void update_br_prob_note (basic_block);
 776 extern bool inside_basic_block_p (const_rtx);
 777 extern bool control_flow_insn_p (const_rtx);
 778 extern rtx get_last_bb_insn (basic_block);
 779
 780 /* In dominance.c */
 781
 782 enum cdi_direction
 783 {
 784   CDI_DOMINATORS = 1,
 785   CDI_POST_DOMINATORS = 2
 786 };
 787
 788 extern enum dom_state dom_info_state (enum cdi_direction);
 789 extern void set_dom_info_availability (enum cdi_direction, enum dom_state);
 790 extern bool dom_info_available_p (enum cdi_direction);
 791 extern void calculate_dominance_info (enum cdi_direction);
 792 extern void free_dominance_info (enum cdi_direction);
 793 extern basic_block nearest_common_dominator (enum cdi_direction,
 794                                              basic_block, basic_block);
 795 extern basic_block nearest_common_dominator_for_set (enum cdi_direction,
 796                                                      bitmap);
 797 extern void set_immediate_dominator (enum cdi_direction, basic_block,
 798                                      basic_block);
 799 extern basic_block get_immediate_dominator (enum cdi_direction, basic_block);
 800 extern bool dominated_by_p (enum cdi_direction, const_basic_block, const_basic_block);
 801 extern VEC (basic_block, heap) *get_dominated_by (enum cdi_direction, basic_block);
 802 extern VEC (basic_block, heap) *get_dominated_by_region (enum cdi_direction,
 803                                                          basic_block *,
 804                                                          unsigned);
 805 extern VEC (basic_block, heap) *get_dominated_to_depth (enum cdi_direction,
 806                                                         basic_block, int);
 807 extern VEC (basic_block, heap) *get_all_dominated_blocks (enum cdi_direction,
 808                                                           basic_block);
 809 extern void add_to_dominance_info (enum cdi_direction, basic_block);
 810 extern void delete_from_dominance_info (enum cdi_direction, basic_block);
 811 basic_block recompute_dominator (enum cdi_direction, basic_block);
 812 extern void redirect_immediate_dominators (enum cdi_direction, basic_block,
 813                                            basic_block);
 814 extern void iterate_fix_dominators (enum cdi_direction,
 815                                     VEC (basic_block, heap) *, bool);
 816 extern void verify_dominators (enum cdi_direction);
 817 extern basic_block first_dom_son (enum cdi_direction, basic_block);
 818 extern basic_block next_dom_son (enum cdi_direction, basic_block);
 819 unsigned bb_dom_dfs_in (enum cdi_direction, basic_block);
 820 unsigned bb_dom_dfs_out (enum cdi_direction, basic_block);
 821
 822 extern edge try_redirect_by_replacing_jump (edge, basic_block, bool);
 823 extern void break_superblocks (void);
 824 extern void relink_block_chain (bool);
 825 extern void update_bb_profile_for_threading (basic_block, int, gcov_type, edge);
 826 extern void init_rtl_bb_info (basic_block);
 827
 828 extern void initialize_original_copy_tables (void);
 829 extern void free_original_copy_tables (void);
 830 extern void set_bb_original (basic_block, basic_block);
 831 extern basic_block get_bb_original (basic_block);
 832 extern void set_bb_copy (basic_block, basic_block);
 833 extern basic_block get_bb_copy (basic_block);
 834 void set_loop_copy (struct loop *, struct loop *);
 835 struct loop *get_loop_copy (struct loop *);
 836
 837 #include "cfghooks.h"
 838
 839 /* Return true when one of the predecessor edges of BB is marked with EDGE_EH.  */
 840 static inline bool
 841 bb_has_eh_pred (basic_block bb)
 842 {
 843   edge e;
 844   edge_iterator ei;
 845
 846   FOR_EACH_EDGE (e, ei, bb->preds)
 847     {
 848       if (e->flags & EDGE_EH)
 849         return true;
 850     }
 851   return false;
 852 }
 853
 854 /* Return true when one of the predecessor edges of BB is marked with EDGE_ABNORMAL.  */
 855 static inline bool
 856 bb_has_abnormal_pred (basic_block bb)
 857 {
 858   edge e;
 859   edge_iterator ei;
 860
 861   FOR_EACH_EDGE (e, ei, bb->preds)
 862     {
 863       if (e->flags & EDGE_ABNORMAL)
 864         return true;
 865     }
 866   return false;
 867 }
 868
 869 /* Return the fallthru edge in EDGES if it exists, NULL otherwise.  */
 870 static inline edge
 871 find_fallthru_edge (VEC(edge,gc) *edges)
 872 {
 873   edge e;
 874   edge_iterator ei;
 875
 876   FOR_EACH_EDGE (e, ei, edges)
 877     if (e->flags & EDGE_FALLTHRU)
 878       break;
 879
 880   return e;
 881 }
 882
 883 /* In cfgloopmanip.c.  */
 884 extern edge mfb_kj_edge;
 885 extern bool mfb_keep_just (edge);
 886
 887 /* In cfgexpand.c.  */
 888 extern void rtl_profile_for_bb (basic_block);
 889 extern void rtl_profile_for_edge (edge);
 890 extern void default_rtl_profile (void);
 891
 892 #endif /* GCC_BASIC_BLOCK_H */