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 typedef unsigned HOST_WIDEST_INT gcov_type_unsigned;
  35
  36 /* Control flow edge information.  */
  37 struct GTY((user)) edge_def {
  38   /* The two blocks at the ends of the edge.  */
  39   basic_block src;
  40   basic_block dest;
  41
  42   /* Instructions queued on the edge.  */
  43   union edge_def_insns {
  44     gimple_seq g;
  45     rtx r;
  46   } insns;
  47
  48   /* Auxiliary info specific to a pass.  */
  49   PTR aux;
  50
  51   /* Location of any goto implicit in the edge and associated BLOCK.  */
  52   tree goto_block;
  53   location_t goto_locus;
  54
  55   /* The index number corresponding to this edge in the edge vector
  56      dest->preds.  */
  57   unsigned int dest_idx;
  58
  59   int flags;                    /* see cfg-flags.def */
  60   int probability;              /* biased by REG_BR_PROB_BASE */
  61   gcov_type count;              /* Expected number of executions calculated
  62                                    in profile.c  */
  63 };
  64
  65 DEF_VEC_P(edge);
  66 DEF_VEC_ALLOC_P(edge,gc);
  67 DEF_VEC_ALLOC_P(edge,heap);
  68
  69 /* Garbage collection and PCH support for edge_def.  */
  70 extern void gt_ggc_mx (edge_def *e);
  71 extern void gt_pch_nx (edge_def *e);
  72 extern void gt_pch_nx (edge_def *e, gt_pointer_operator, void *);
  73
  74 /* Masks for edge.flags.  */
  75 #define DEF_EDGE_FLAG(NAME,IDX) EDGE_##NAME = 1 << IDX ,
  76 enum cfg_edge_flags {
  77 #include "cfg-flags.def"
  78   LAST_CFG_EDGE_FLAG            /* this is only used for EDGE_ALL_FLAGS */
  79 };
  80 #undef DEF_EDGE_FLAG
  81
  82 /* Bit mask for all edge flags.  */
  83 #define EDGE_ALL_FLAGS          ((LAST_CFG_EDGE_FLAG - 1) * 2 - 1)
  84
  85 /* The following four flags all indicate something special about an edge.
  86    Test the edge flags on EDGE_COMPLEX to detect all forms of "strange"
  87    control flow transfers.  */
  88 #define EDGE_COMPLEX \
  89   (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH | EDGE_PRESERVE)
  90
  91 /* Counter summary from the last set of coverage counts read by
  92    profile.c.  */
  93 extern const struct gcov_ctr_summary *profile_info;
  94
  95 /* Working set size statistics for a given percentage of the entire
  96    profile (sum_all from the counter summary).  */
  97 typedef struct gcov_working_set_info
  98 {
  99   /* Number of hot counters included in this working set.  */
 100   unsigned num_counters;
 101   /* Smallest counter included in this working set.  */
 102   gcov_type min_counter;
 103 } gcov_working_set_t;
 104
 105 /* Declared in cfgloop.h.  */
 106 struct loop;
 107
 108 struct GTY(()) rtl_bb_info {
 109   /* The first insn of the block is embedded into bb->il.x.  */
 110   /* The last insn of the block.  */
 111   rtx end_;
 112
 113   /* In CFGlayout mode points to insn notes/jumptables to be placed just before
 114      and after the block.   */
 115   rtx header_;
 116   rtx footer_;
 117 };
 118
 119 struct GTY(()) gimple_bb_info {
 120   /* Sequence of statements in this block.  */
 121   gimple_seq seq;
 122
 123   /* PHI nodes for this block.  */
 124   gimple_seq phi_nodes;
 125 };
 126
 127 /* A basic block is a sequence of instructions with only one entry and
 128    only one exit.  If any one of the instructions are executed, they
 129    will all be executed, and in sequence from first to last.
 130
 131    There may be COND_EXEC instructions in the basic block.  The
 132    COND_EXEC *instructions* will be executed -- but if the condition
 133    is false the conditionally executed *expressions* will of course
 134    not be executed.  We don't consider the conditionally executed
 135    expression (which might have side-effects) to be in a separate
 136    basic block because the program counter will always be at the same
 137    location after the COND_EXEC instruction, regardless of whether the
 138    condition is true or not.
 139
 140    Basic blocks need not start with a label nor end with a jump insn.
 141    For example, a previous basic block may just "conditionally fall"
 142    into the succeeding basic block, and the last basic block need not
 143    end with a jump insn.  Block 0 is a descendant of the entry block.
 144
 145    A basic block beginning with two labels cannot have notes between
 146    the labels.
 147
 148    Data for jump tables are stored in jump_insns that occur in no
 149    basic block even though these insns can follow or precede insns in
 150    basic blocks.  */
 151
 152 /* Basic block information indexed by block number.  */
 153 struct GTY((chain_next ("%h.next_bb"), chain_prev ("%h.prev_bb"))) basic_block_def {
 154   /* The edges into and out of the block.  */
 155   VEC(edge,gc) *preds;
 156   VEC(edge,gc) *succs;
 157
 158   /* Auxiliary info specific to a pass.  */
 159   PTR GTY ((skip (""))) aux;
 160
 161   /* Innermost loop containing the block.  */
 162   struct loop *loop_father;
 163
 164   /* The dominance and postdominance information node.  */
 165   struct et_node * GTY ((skip (""))) dom[2];
 166
 167   /* Previous and next blocks in the chain.  */
 168   basic_block prev_bb;
 169   basic_block next_bb;
 170
 171   union basic_block_il_dependent {
 172       struct gimple_bb_info GTY ((tag ("0"))) gimple;
 173       struct {
 174         rtx head_;
 175         struct rtl_bb_info * rtl;
 176       } GTY ((tag ("1"))) x;
 177     } GTY ((desc ("((%1.flags & BB_RTL) != 0)"))) il;
 178
 179   /* Various flags.  See cfg-flags.def.  */
 180   int flags;
 181
 182   /* The index of this block.  */
 183   int index;
 184
 185   /* Expected number of executions: calculated in profile.c.  */
 186   gcov_type count;
 187
 188   /* Expected frequency.  Normalized to be in range 0 to BB_FREQ_MAX.  */
 189   int frequency;
 190
 191   /* The discriminator for this block.  The discriminator distinguishes
 192      among several basic blocks that share a common locus, allowing for
 193      more accurate sample-based profiling.  */
 194   int discriminator;
 195 };
 196
 197 /* This ensures that struct gimple_bb_info is smaller than
 198    struct rtl_bb_info, so that inlining the former into basic_block_def
 199    is the better choice.  */
 200 typedef int __assert_gimple_bb_smaller_rtl_bb
 201               [(int)sizeof(struct rtl_bb_info)
 202                - (int)sizeof (struct gimple_bb_info)];
 203
 204 DEF_VEC_P(basic_block);
 205 DEF_VEC_ALLOC_P(basic_block,gc);
 206 DEF_VEC_ALLOC_P(basic_block,heap);
 207
 208 #define BB_FREQ_MAX 10000
 209
 210 /* Masks for basic_block.flags.  */
 211 #define DEF_BASIC_BLOCK_FLAG(NAME,IDX) BB_##NAME = 1 << IDX ,
 212 enum cfg_bb_flags
 213 {
 214 #include "cfg-flags.def"
 215   LAST_CFG_BB_FLAG              /* this is only used for BB_ALL_FLAGS */
 216 };
 217 #undef DEF_BASIC_BLOCK_FLAG
 218
 219 /* Bit mask for all basic block flags.  */
 220 #define BB_ALL_FLAGS            ((LAST_CFG_BB_FLAG - 1) * 2 - 1)
 221
 222 /* Bit mask for all basic block flags that must be preserved.  These are
 223    the bit masks that are *not* cleared by clear_bb_flags.  */
 224 #define BB_FLAGS_TO_PRESERVE                                    \
 225   (BB_DISABLE_SCHEDULE | BB_RTL | BB_NON_LOCAL_GOTO_TARGET      \
 226    | BB_HOT_PARTITION | BB_COLD_PARTITION)
 227
 228 /* Dummy bitmask for convenience in the hot/cold partitioning code.  */
 229 #define BB_UNPARTITIONED        0
 230
 231 /* Partitions, to be used when partitioning hot and cold basic blocks into
 232    separate sections.  */
 233 #define BB_PARTITION(bb) ((bb)->flags & (BB_HOT_PARTITION|BB_COLD_PARTITION))
 234 #define BB_SET_PARTITION(bb, part) do {                                 \
 235   basic_block bb_ = (bb);                                               \
 236   bb_->flags = ((bb_->flags & ~(BB_HOT_PARTITION|BB_COLD_PARTITION))    \
 237                 | (part));                                              \
 238 } while (0)
 239
 240 #define BB_COPY_PARTITION(dstbb, srcbb) \
 241   BB_SET_PARTITION (dstbb, BB_PARTITION (srcbb))
 242
 243 /* State of dominance information.  */
 244
 245 enum dom_state
 246 {
 247   DOM_NONE,             /* Not computed at all.  */
 248   DOM_NO_FAST_QUERY,    /* The data is OK, but the fast query data are not usable.  */
 249   DOM_OK                /* Everything is ok.  */
 250 };
 251
 252 /* What sort of profiling information we have.  */
 253 enum profile_status_d
 254 {
 255   PROFILE_ABSENT,
 256   PROFILE_GUESSED,
 257   PROFILE_READ,
 258   PROFILE_LAST  /* Last value, used by profile streaming.  */
 259 };
 260
 261 /* A structure to group all the per-function control flow graph data.
 262    The x_* prefixing is necessary because otherwise references to the
 263    fields of this struct are interpreted as the defines for backward
 264    source compatibility following the definition of this struct.  */
 265 struct GTY(()) control_flow_graph {
 266   /* Block pointers for the exit and entry of a function.
 267      These are always the head and tail of the basic block list.  */
 268   basic_block x_entry_block_ptr;
 269   basic_block x_exit_block_ptr;
 270
 271   /* Index by basic block number, get basic block struct info.  */
 272   VEC(basic_block,gc) *x_basic_block_info;
 273
 274   /* Number of basic blocks in this flow graph.  */
 275   int x_n_basic_blocks;
 276
 277   /* Number of edges in this flow graph.  */
 278   int x_n_edges;
 279
 280   /* The first free basic block number.  */
 281   int x_last_basic_block;
 282
 283   /* UIDs for LABEL_DECLs.  */
 284   int last_label_uid;
 285
 286   /* Mapping of labels to their associated blocks.  At present
 287      only used for the gimple CFG.  */
 288   VEC(basic_block,gc) *x_label_to_block_map;
 289
 290   enum profile_status_d x_profile_status;
 291
 292   /* Whether the dominators and the postdominators are available.  */
 293   enum dom_state x_dom_computed[2];
 294
 295   /* Number of basic blocks in the dominance tree.  */
 296   unsigned x_n_bbs_in_dom_tree[2];
 297
 298   /* Maximal number of entities in the single jumptable.  Used to estimate
 299      final flowgraph size.  */
 300   int max_jumptable_ents;
 301 };
 302
 303 /* Defines for accessing the fields of the CFG structure for function FN.  */
 304 #define ENTRY_BLOCK_PTR_FOR_FUNCTION(FN)     ((FN)->cfg->x_entry_block_ptr)
 305 #define EXIT_BLOCK_PTR_FOR_FUNCTION(FN)      ((FN)->cfg->x_exit_block_ptr)
 306 #define basic_block_info_for_function(FN)    ((FN)->cfg->x_basic_block_info)
 307 #define n_basic_blocks_for_function(FN)      ((FN)->cfg->x_n_basic_blocks)
 308 #define n_edges_for_function(FN)             ((FN)->cfg->x_n_edges)
 309 #define last_basic_block_for_function(FN)    ((FN)->cfg->x_last_basic_block)
 310 #define label_to_block_map_for_function(FN)  ((FN)->cfg->x_label_to_block_map)
 311 #define profile_status_for_function(FN)      ((FN)->cfg->x_profile_status)
 312
 313 #define BASIC_BLOCK_FOR_FUNCTION(FN,N) \
 314   (VEC_index (basic_block, basic_block_info_for_function(FN), (N)))
 315 #define SET_BASIC_BLOCK_FOR_FUNCTION(FN,N,BB) \
 316   (VEC_replace (basic_block, basic_block_info_for_function(FN), (N), (BB)))
 317
 318 /* Defines for textual backward source compatibility.  */
 319 #define ENTRY_BLOCK_PTR         (cfun->cfg->x_entry_block_ptr)
 320 #define EXIT_BLOCK_PTR          (cfun->cfg->x_exit_block_ptr)
 321 #define basic_block_info        (cfun->cfg->x_basic_block_info)
 322 #define n_basic_blocks          (cfun->cfg->x_n_basic_blocks)
 323 #define n_edges                 (cfun->cfg->x_n_edges)
 324 #define last_basic_block        (cfun->cfg->x_last_basic_block)
 325 #define label_to_block_map      (cfun->cfg->x_label_to_block_map)
 326 #define profile_status          (cfun->cfg->x_profile_status)
 327
 328 #define BASIC_BLOCK(N)          (VEC_index (basic_block, basic_block_info, (N)))
 329 #define SET_BASIC_BLOCK(N,BB)   (VEC_replace (basic_block, basic_block_info, (N), (BB)))
 330
 331 /* For iterating over basic blocks.  */
 332 #define FOR_BB_BETWEEN(BB, FROM, TO, DIR) \
 333   for (BB = FROM; BB != TO; BB = BB->DIR)
 334
 335 #define FOR_EACH_BB_FN(BB, FN) \
 336   FOR_BB_BETWEEN (BB, (FN)->cfg->x_entry_block_ptr->next_bb, (FN)->cfg->x_exit_block_ptr, next_bb)
 337
 338 #define FOR_EACH_BB(BB) FOR_EACH_BB_FN (BB, cfun)
 339
 340 #define FOR_EACH_BB_REVERSE_FN(BB, FN) \
 341   FOR_BB_BETWEEN (BB, (FN)->cfg->x_exit_block_ptr->prev_bb, (FN)->cfg->x_entry_block_ptr, prev_bb)
 342
 343 #define FOR_EACH_BB_REVERSE(BB) FOR_EACH_BB_REVERSE_FN(BB, cfun)
 344
 345 /* For iterating over insns in basic block.  */
 346 #define FOR_BB_INSNS(BB, INSN)                  \
 347   for ((INSN) = BB_HEAD (BB);                   \
 348        (INSN) && (INSN) != NEXT_INSN (BB_END (BB));     \
 349        (INSN) = NEXT_INSN (INSN))
 350
 351 /* For iterating over insns in basic block when we might remove the
 352    current insn.  */
 353 #define FOR_BB_INSNS_SAFE(BB, INSN, CURR)                       \
 354   for ((INSN) = BB_HEAD (BB), (CURR) = (INSN) ? NEXT_INSN ((INSN)): NULL;       \
 355        (INSN) && (INSN) != NEXT_INSN (BB_END (BB));     \
 356        (INSN) = (CURR), (CURR) = (INSN) ? NEXT_INSN ((INSN)) : NULL)
 357
 358 #define FOR_BB_INSNS_REVERSE(BB, INSN)          \
 359   for ((INSN) = BB_END (BB);                    \
 360        (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));    \
 361        (INSN) = PREV_INSN (INSN))
 362
 363 #define FOR_BB_INSNS_REVERSE_SAFE(BB, INSN, CURR)       \
 364   for ((INSN) = BB_END (BB),(CURR) = (INSN) ? PREV_INSN ((INSN)) : NULL;        \
 365        (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));    \
 366        (INSN) = (CURR), (CURR) = (INSN) ? PREV_INSN ((INSN)) : NULL)
 367
 368 /* Cycles through _all_ basic blocks, even the fake ones (entry and
 369    exit block).  */
 370
 371 #define FOR_ALL_BB(BB) \
 372   for (BB = ENTRY_BLOCK_PTR; BB; BB = BB->next_bb)
 373
 374 #define FOR_ALL_BB_FN(BB, FN) \
 375   for (BB = ENTRY_BLOCK_PTR_FOR_FUNCTION (FN); BB; BB = BB->next_bb)
 376
 377 \f
 378 /* Stuff for recording basic block info.  */
 379
 380 #define BB_HEAD(B)      (B)->il.x.head_
 381 #define BB_END(B)       (B)->il.x.rtl->end_
 382 #define BB_HEADER(B)    (B)->il.x.rtl->header_
 383 #define BB_FOOTER(B)    (B)->il.x.rtl->footer_
 384
 385 /* Special block numbers [markers] for entry and exit.
 386    Neither of them is supposed to hold actual statements.  */
 387 #define ENTRY_BLOCK (0)
 388 #define EXIT_BLOCK (1)
 389
 390 /* The two blocks that are always in the cfg.  */
 391 #define NUM_FIXED_BLOCKS (2)
 392
 393 #define set_block_for_insn(INSN, BB)  (BLOCK_FOR_INSN (INSN) = BB)
 394
 395 extern void compute_bb_for_insn (void);
 396 extern unsigned int free_bb_for_insn (void);
 397 extern void update_bb_for_insn (basic_block);
 398
 399 extern void insert_insn_on_edge (rtx, edge);
 400 basic_block split_edge_and_insert (edge, rtx);
 401
 402 extern void commit_one_edge_insertion (edge e);
 403 extern void commit_edge_insertions (void);
 404
 405 extern edge unchecked_make_edge (basic_block, basic_block, int);
 406 extern edge cached_make_edge (sbitmap, basic_block, basic_block, int);
 407 extern edge make_edge (basic_block, basic_block, int);
 408 extern edge make_single_succ_edge (basic_block, basic_block, int);
 409 extern void remove_edge_raw (edge);
 410 extern void redirect_edge_succ (edge, basic_block);
 411 extern edge redirect_edge_succ_nodup (edge, basic_block);
 412 extern void redirect_edge_pred (edge, basic_block);
 413 extern basic_block create_basic_block_structure (rtx, rtx, rtx, basic_block);
 414 extern void clear_bb_flags (void);
 415 extern void dump_bb_info (FILE *, basic_block, int, int, bool, bool);
 416 extern void dump_edge_info (FILE *, edge, int, int);
 417 extern void brief_dump_cfg (FILE *, int);
 418 extern void clear_edges (void);
 419 extern void scale_bbs_frequencies_int (basic_block *, int, int, int);
 420 extern void scale_bbs_frequencies_gcov_type (basic_block *, int, gcov_type,
 421                                              gcov_type);
 422
 423 /* Structure to group all of the information to process IF-THEN and
 424    IF-THEN-ELSE blocks for the conditional execution support.  This
 425    needs to be in a public file in case the IFCVT macros call
 426    functions passing the ce_if_block data structure.  */
 427
 428 typedef struct ce_if_block
 429 {
 430   basic_block test_bb;                  /* First test block.  */
 431   basic_block then_bb;                  /* THEN block.  */
 432   basic_block else_bb;                  /* ELSE block or NULL.  */
 433   basic_block join_bb;                  /* Join THEN/ELSE blocks.  */
 434   basic_block last_test_bb;             /* Last bb to hold && or || tests.  */
 435   int num_multiple_test_blocks;         /* # of && and || basic blocks.  */
 436   int num_and_and_blocks;               /* # of && blocks.  */
 437   int num_or_or_blocks;                 /* # of || blocks.  */
 438   int num_multiple_test_insns;          /* # of insns in && and || blocks.  */
 439   int and_and_p;                        /* Complex test is &&.  */
 440   int num_then_insns;                   /* # of insns in THEN block.  */
 441   int num_else_insns;                   /* # of insns in ELSE block.  */
 442   int pass;                             /* Pass number.  */
 443 } ce_if_block_t;
 444
 445 /* This structure maintains an edge list vector.  */
 446 /* FIXME: Make this a VEC(edge).  */
 447 struct edge_list
 448 {
 449   int num_edges;
 450   edge *index_to_edge;
 451 };
 452
 453 /* The base value for branch probability notes and edge probabilities.  */
 454 #define REG_BR_PROB_BASE  10000
 455
 456 /* This is the value which indicates no edge is present.  */
 457 #define EDGE_INDEX_NO_EDGE      -1
 458
 459 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 460    if there is no edge between the 2 basic blocks.  */
 461 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 462
 463 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 464    block which is either the pred or succ end of the indexed edge.  */
 465 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 466 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 467
 468 /* INDEX_EDGE returns a pointer to the edge.  */
 469 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 470
 471 /* Number of edges in the compressed edge list.  */
 472 #define NUM_EDGES(el)                   ((el)->num_edges)
 473
 474 /* BB is assumed to contain conditional jump.  Return the fallthru edge.  */
 475 #define FALLTHRU_EDGE(bb)               (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
 476                                          ? EDGE_SUCC ((bb), 0) : EDGE_SUCC ((bb), 1))
 477
 478 /* BB is assumed to contain conditional jump.  Return the branch edge.  */
 479 #define BRANCH_EDGE(bb)                 (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
 480                                          ? EDGE_SUCC ((bb), 1) : EDGE_SUCC ((bb), 0))
 481
 482 /* Return expected execution frequency of the edge E.  */
 483 #define EDGE_FREQUENCY(e)               (((e)->src->frequency \
 484                                           * (e)->probability \
 485                                           + REG_BR_PROB_BASE / 2) \
 486                                          / REG_BR_PROB_BASE)
 487
 488 /* Return nonzero if edge is critical.  */
 489 #define EDGE_CRITICAL_P(e)              (EDGE_COUNT ((e)->src->succs) >= 2 \
 490                                          && EDGE_COUNT ((e)->dest->preds) >= 2)
 491
 492 #define EDGE_COUNT(ev)                  VEC_length (edge, (ev))
 493 #define EDGE_I(ev,i)                    VEC_index  (edge, (ev), (i))
 494 #define EDGE_PRED(bb,i)                 VEC_index  (edge, (bb)->preds, (i))
 495 #define EDGE_SUCC(bb,i)                 VEC_index  (edge, (bb)->succs, (i))
 496
 497 /* Returns true if BB has precisely one successor.  */
 498
 499 static inline bool
 500 single_succ_p (const_basic_block bb)
 501 {
 502   return EDGE_COUNT (bb->succs) == 1;
 503 }
 504
 505 /* Returns true if BB has precisely one predecessor.  */
 506
 507 static inline bool
 508 single_pred_p (const_basic_block bb)
 509 {
 510   return EDGE_COUNT (bb->preds) == 1;
 511 }
 512
 513 /* Returns the single successor edge of basic block BB.  Aborts if
 514    BB does not have exactly one successor.  */
 515
 516 static inline edge
 517 single_succ_edge (const_basic_block bb)
 518 {
 519   gcc_checking_assert (single_succ_p (bb));
 520   return EDGE_SUCC (bb, 0);
 521 }
 522
 523 /* Returns the single predecessor edge of basic block BB.  Aborts
 524    if BB does not have exactly one predecessor.  */
 525
 526 static inline edge
 527 single_pred_edge (const_basic_block bb)
 528 {
 529   gcc_checking_assert (single_pred_p (bb));
 530   return EDGE_PRED (bb, 0);
 531 }
 532
 533 /* Returns the single successor block of basic block BB.  Aborts
 534    if BB does not have exactly one successor.  */
 535
 536 static inline basic_block
 537 single_succ (const_basic_block bb)
 538 {
 539   return single_succ_edge (bb)->dest;
 540 }
 541
 542 /* Returns the single predecessor block of basic block BB.  Aborts
 543    if BB does not have exactly one predecessor.*/
 544
 545 static inline basic_block
 546 single_pred (const_basic_block bb)
 547 {
 548   return single_pred_edge (bb)->src;
 549 }
 550
 551 /* Iterator object for edges.  */
 552
 553 typedef struct {
 554   unsigned index;
 555   VEC(edge,gc) **container;
 556 } edge_iterator;
 557
 558 static inline VEC(edge,gc) *
 559 ei_container (edge_iterator i)
 560 {
 561   gcc_checking_assert (i.container);
 562   return *i.container;
 563 }
 564
 565 #define ei_start(iter) ei_start_1 (&(iter))
 566 #define ei_last(iter) ei_last_1 (&(iter))
 567
 568 /* Return an iterator pointing to the start of an edge vector.  */
 569 static inline edge_iterator
 570 ei_start_1 (VEC(edge,gc) **ev)
 571 {
 572   edge_iterator i;
 573
 574   i.index = 0;
 575   i.container = ev;
 576
 577   return i;
 578 }
 579
 580 /* Return an iterator pointing to the last element of an edge
 581    vector.  */
 582 static inline edge_iterator
 583 ei_last_1 (VEC(edge,gc) **ev)
 584 {
 585   edge_iterator i;
 586
 587   i.index = EDGE_COUNT (*ev) - 1;
 588   i.container = ev;
 589
 590   return i;
 591 }
 592
 593 /* Is the iterator `i' at the end of the sequence?  */
 594 static inline bool
 595 ei_end_p (edge_iterator i)
 596 {
 597   return (i.index == EDGE_COUNT (ei_container (i)));
 598 }
 599
 600 /* Is the iterator `i' at one position before the end of the
 601    sequence?  */
 602 static inline bool
 603 ei_one_before_end_p (edge_iterator i)
 604 {
 605   return (i.index + 1 == EDGE_COUNT (ei_container (i)));
 606 }
 607
 608 /* Advance the iterator to the next element.  */
 609 static inline void
 610 ei_next (edge_iterator *i)
 611 {
 612   gcc_checking_assert (i->index < EDGE_COUNT (ei_container (*i)));
 613   i->index++;
 614 }
 615
 616 /* Move the iterator to the previous element.  */
 617 static inline void
 618 ei_prev (edge_iterator *i)
 619 {
 620   gcc_checking_assert (i->index > 0);
 621   i->index--;
 622 }
 623
 624 /* Return the edge pointed to by the iterator `i'.  */
 625 static inline edge
 626 ei_edge (edge_iterator i)
 627 {
 628   return EDGE_I (ei_container (i), i.index);
 629 }
 630
 631 /* Return an edge pointed to by the iterator.  Do it safely so that
 632    NULL is returned when the iterator is pointing at the end of the
 633    sequence.  */
 634 static inline edge
 635 ei_safe_edge (edge_iterator i)
 636 {
 637   return !ei_end_p (i) ? ei_edge (i) : NULL;
 638 }
 639
 640 /* Return 1 if we should continue to iterate.  Return 0 otherwise.
 641    *Edge P is set to the next edge if we are to continue to iterate
 642    and NULL otherwise.  */
 643
 644 static inline bool
 645 ei_cond (edge_iterator ei, edge *p)
 646 {
 647   if (!ei_end_p (ei))
 648     {
 649       *p = ei_edge (ei);
 650       return 1;
 651     }
 652   else
 653     {
 654       *p = NULL;
 655       return 0;
 656     }
 657 }
 658
 659 /* This macro serves as a convenient way to iterate each edge in a
 660    vector of predecessor or successor edges.  It must not be used when
 661    an element might be removed during the traversal, otherwise
 662    elements will be missed.  Instead, use a for-loop like that shown
 663    in the following pseudo-code:
 664
 665    FOR (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
 666      {
 667         IF (e != taken_edge)
 668           remove_edge (e);
 669         ELSE
 670           ei_next (&ei);
 671      }
 672 */
 673
 674 #define FOR_EACH_EDGE(EDGE,ITER,EDGE_VEC)       \
 675   for ((ITER) = ei_start ((EDGE_VEC));          \
 676        ei_cond ((ITER), &(EDGE));               \
 677        ei_next (&(ITER)))
 678
 679 #define CLEANUP_EXPENSIVE       1       /* Do relatively expensive optimizations
 680                                            except for edge forwarding */
 681 #define CLEANUP_CROSSJUMP       2       /* Do crossjumping.  */
 682 #define CLEANUP_POST_REGSTACK   4       /* We run after reg-stack and need
 683                                            to care REG_DEAD notes.  */
 684 #define CLEANUP_THREADING       8       /* Do jump threading.  */
 685 #define CLEANUP_NO_INSN_DEL     16      /* Do not try to delete trivially dead
 686                                            insns.  */
 687 #define CLEANUP_CFGLAYOUT       32      /* Do cleanup in cfglayout mode.  */
 688 #define CLEANUP_CFG_CHANGED     64      /* The caller changed the CFG.  */
 689
 690 /* In cfganal.c */
 691 extern void sbitmap_intersection_of_succs (sbitmap, sbitmap *, basic_block);
 692 extern void sbitmap_intersection_of_preds (sbitmap, sbitmap *, basic_block);
 693 extern void sbitmap_union_of_succs (sbitmap, sbitmap *, basic_block);
 694 extern void sbitmap_union_of_preds (sbitmap, sbitmap *, basic_block);
 695
 696 /* In lcm.c */
 697 extern struct edge_list *pre_edge_lcm (int, sbitmap *, sbitmap *,
 698                                        sbitmap *, sbitmap *, sbitmap **,
 699                                        sbitmap **);
 700 extern struct edge_list *pre_edge_rev_lcm (int, sbitmap *,
 701                                            sbitmap *, sbitmap *,
 702                                            sbitmap *, sbitmap **,
 703                                            sbitmap **);
 704 extern void compute_available (sbitmap *, sbitmap *, sbitmap *, sbitmap *);
 705
 706 /* In predict.c */
 707 extern bool maybe_hot_bb_p (struct function *, const_basic_block);
 708 extern bool maybe_hot_edge_p (edge);
 709 extern bool probably_never_executed_bb_p (struct function *, const_basic_block);
 710 extern bool optimize_bb_for_size_p (const_basic_block);
 711 extern bool optimize_bb_for_speed_p (const_basic_block);
 712 extern bool optimize_edge_for_size_p (edge);
 713 extern bool optimize_edge_for_speed_p (edge);
 714 extern bool optimize_loop_for_size_p (struct loop *);
 715 extern bool optimize_loop_for_speed_p (struct loop *);
 716 extern bool optimize_loop_nest_for_size_p (struct loop *);
 717 extern bool optimize_loop_nest_for_speed_p (struct loop *);
 718 extern bool gimple_predicted_by_p (const_basic_block, enum br_predictor);
 719 extern bool rtl_predicted_by_p (const_basic_block, enum br_predictor);
 720 extern void gimple_predict_edge (edge, enum br_predictor, int);
 721 extern void rtl_predict_edge (edge, enum br_predictor, int);
 722 extern void predict_edge_def (edge, enum br_predictor, enum prediction);
 723 extern void guess_outgoing_edge_probabilities (basic_block);
 724 extern void remove_predictions_associated_with_edge (edge);
 725 extern bool edge_probability_reliable_p (const_edge);
 726 extern bool br_prob_note_reliable_p (const_rtx);
 727 extern bool predictable_edge_p (edge);
 728
 729 /* In cfg.c  */
 730 extern void init_flow (struct function *);
 731 extern void debug_bb (basic_block);
 732 extern basic_block debug_bb_n (int);
 733 extern void dump_flow_info (FILE *, int);
 734 extern void expunge_block (basic_block);
 735 extern void link_block (basic_block, basic_block);
 736 extern void unlink_block (basic_block);
 737 extern void compact_blocks (void);
 738 extern basic_block alloc_block (void);
 739 extern void alloc_aux_for_blocks (int);
 740 extern void clear_aux_for_blocks (void);
 741 extern void free_aux_for_blocks (void);
 742 extern void alloc_aux_for_edge (edge, int);
 743 extern void alloc_aux_for_edges (int);
 744 extern void clear_aux_for_edges (void);
 745 extern void free_aux_for_edges (void);
 746
 747 /* In cfganal.c  */
 748 extern void find_unreachable_blocks (void);
 749 extern bool mark_dfs_back_edges (void);
 750 struct edge_list * create_edge_list (void);
 751 void free_edge_list (struct edge_list *);
 752 void print_edge_list (FILE *, struct edge_list *);
 753 void verify_edge_list (FILE *, struct edge_list *);
 754 int find_edge_index (struct edge_list *, basic_block, basic_block);
 755 edge find_edge (basic_block, basic_block);
 756 extern void remove_fake_edges (void);
 757 extern void remove_fake_exit_edges (void);
 758 extern void add_noreturn_fake_exit_edges (void);
 759 extern void connect_infinite_loops_to_exit (void);
 760 extern int post_order_compute (int *, bool, bool);
 761 extern int inverted_post_order_compute (int *);
 762 extern int pre_and_rev_post_order_compute (int *, int *, bool);
 763 extern int dfs_enumerate_from (basic_block, int,
 764                                bool (*)(const_basic_block, const void *),
 765                                basic_block *, int, const void *);
 766 extern void compute_dominance_frontiers (struct bitmap_head_def *);
 767 extern bitmap compute_idf (bitmap, struct bitmap_head_def *);
 768
 769 /* In cfgrtl.c  */
 770 extern rtx block_label (basic_block);
 771 extern rtx bb_note (basic_block);
 772 extern bool purge_all_dead_edges (void);
 773 extern bool purge_dead_edges (basic_block);
 774 extern bool fixup_abnormal_edges (void);
 775 extern basic_block force_nonfallthru_and_redirect (edge, basic_block, rtx);
 776 extern bool forwarder_block_p (const_basic_block);
 777 extern bool can_fallthru (basic_block, basic_block);
 778
 779 /* In cfgbuild.c.  */
 780 extern void find_many_sub_basic_blocks (sbitmap);
 781 extern void rtl_make_eh_edge (sbitmap, basic_block, rtx);
 782
 783 enum replace_direction { dir_none, dir_forward, dir_backward, dir_both };
 784
 785 /* In cfgcleanup.c.  */
 786 extern bool cleanup_cfg (int);
 787 extern int flow_find_cross_jump (basic_block, basic_block, rtx *, rtx *,
 788                                  enum replace_direction*);
 789 extern int flow_find_head_matching_sequence (basic_block, basic_block,
 790                                              rtx *, rtx *, int);
 791
 792 extern bool delete_unreachable_blocks (void);
 793
 794 extern void update_br_prob_note (basic_block);
 795 extern bool inside_basic_block_p (const_rtx);
 796 extern bool control_flow_insn_p (const_rtx);
 797 extern rtx get_last_bb_insn (basic_block);
 798
 799 /* In dominance.c */
 800
 801 enum cdi_direction
 802 {
 803   CDI_DOMINATORS = 1,
 804   CDI_POST_DOMINATORS = 2
 805 };
 806
 807 extern enum dom_state dom_info_state (enum cdi_direction);
 808 extern void set_dom_info_availability (enum cdi_direction, enum dom_state);
 809 extern bool dom_info_available_p (enum cdi_direction);
 810 extern void calculate_dominance_info (enum cdi_direction);
 811 extern void free_dominance_info (enum cdi_direction);
 812 extern basic_block nearest_common_dominator (enum cdi_direction,
 813                                              basic_block, basic_block);
 814 extern basic_block nearest_common_dominator_for_set (enum cdi_direction,
 815                                                      bitmap);
 816 extern void set_immediate_dominator (enum cdi_direction, basic_block,
 817                                      basic_block);
 818 extern basic_block get_immediate_dominator (enum cdi_direction, basic_block);
 819 extern bool dominated_by_p (enum cdi_direction, const_basic_block, const_basic_block);
 820 extern VEC (basic_block, heap) *get_dominated_by (enum cdi_direction, basic_block);
 821 extern VEC (basic_block, heap) *get_dominated_by_region (enum cdi_direction,
 822                                                          basic_block *,
 823                                                          unsigned);
 824 extern VEC (basic_block, heap) *get_dominated_to_depth (enum cdi_direction,
 825                                                         basic_block, int);
 826 extern VEC (basic_block, heap) *get_all_dominated_blocks (enum cdi_direction,
 827                                                           basic_block);
 828 extern void add_to_dominance_info (enum cdi_direction, basic_block);
 829 extern void delete_from_dominance_info (enum cdi_direction, basic_block);
 830 basic_block recompute_dominator (enum cdi_direction, basic_block);
 831 extern void redirect_immediate_dominators (enum cdi_direction, basic_block,
 832                                            basic_block);
 833 extern void iterate_fix_dominators (enum cdi_direction,
 834                                     VEC (basic_block, heap) *, bool);
 835 extern void verify_dominators (enum cdi_direction);
 836 extern basic_block first_dom_son (enum cdi_direction, basic_block);
 837 extern basic_block next_dom_son (enum cdi_direction, basic_block);
 838 unsigned bb_dom_dfs_in (enum cdi_direction, basic_block);
 839 unsigned bb_dom_dfs_out (enum cdi_direction, basic_block);
 840
 841 extern edge try_redirect_by_replacing_jump (edge, basic_block, bool);
 842 extern void break_superblocks (void);
 843 extern void relink_block_chain (bool);
 844 extern void update_bb_profile_for_threading (basic_block, int, gcov_type, edge);
 845 extern void init_rtl_bb_info (basic_block);
 846
 847 extern void initialize_original_copy_tables (void);
 848 extern void free_original_copy_tables (void);
 849 extern void set_bb_original (basic_block, basic_block);
 850 extern basic_block get_bb_original (basic_block);
 851 extern void set_bb_copy (basic_block, basic_block);
 852 extern basic_block get_bb_copy (basic_block);
 853 void set_loop_copy (struct loop *, struct loop *);
 854 struct loop *get_loop_copy (struct loop *);
 855
 856 #include "cfghooks.h"
 857
 858 /* Return true when one of the predecessor edges of BB is marked with EDGE_EH.  */
 859 static inline bool
 860 bb_has_eh_pred (basic_block bb)
 861 {
 862   edge e;
 863   edge_iterator ei;
 864
 865   FOR_EACH_EDGE (e, ei, bb->preds)
 866     {
 867       if (e->flags & EDGE_EH)
 868         return true;
 869     }
 870   return false;
 871 }
 872
 873 /* Return true when one of the predecessor edges of BB is marked with EDGE_ABNORMAL.  */
 874 static inline bool
 875 bb_has_abnormal_pred (basic_block bb)
 876 {
 877   edge e;
 878   edge_iterator ei;
 879
 880   FOR_EACH_EDGE (e, ei, bb->preds)
 881     {
 882       if (e->flags & EDGE_ABNORMAL)
 883         return true;
 884     }
 885   return false;
 886 }
 887
 888 /* Return the fallthru edge in EDGES if it exists, NULL otherwise.  */
 889 static inline edge
 890 find_fallthru_edge (VEC(edge,gc) *edges)
 891 {
 892   edge e;
 893   edge_iterator ei;
 894
 895   FOR_EACH_EDGE (e, ei, edges)
 896     if (e->flags & EDGE_FALLTHRU)
 897       break;
 898
 899   return e;
 900 }
 901
 902 /* In cfgloopmanip.c.  */
 903 extern edge mfb_kj_edge;
 904 extern bool mfb_keep_just (edge);
 905
 906 /* In cfgexpand.c.  */
 907 extern void rtl_profile_for_bb (basic_block);
 908 extern void rtl_profile_for_edge (edge);
 909 extern void default_rtl_profile (void);
 910
 911 /* In profile.c.  */
 912 extern gcov_working_set_t *find_working_set(unsigned pct_times_10);
 913
 914 #endif /* GCC_BASIC_BLOCK_H */