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