gcc/basic-block.h

   1 /* Define control flow data structures for the CFG.
   2    Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   3    2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GCC_BASIC_BLOCK_H
  22 #define GCC_BASIC_BLOCK_H
  23
  24 #include "predict.h"
  25 #include "vec.h"
  26 #include "function.h"
  27
  28 /* Type we use to hold basic block counters.  Should be at least
  29    64bit.  Although a counter cannot be negative, we use a signed
  30    type, because erroneous negative counts can be generated when the
  31    flow graph is manipulated by various optimizations.  A signed type
  32    makes those easy to detect.  */
  33 typedef HOST_WIDEST_INT gcov_type;
  34
  35 /* Control flow edge information.  */
  36 struct GTY(()) edge_def {
  37   /* The two blocks at the ends of the edge.  */
  38   struct basic_block_def *src;
  39   struct basic_block_def *dest;
  40
  41   /* Instructions queued on the edge.  */
  42   union edge_def_insns {
  43     gimple_seq GTY ((tag ("true"))) g;
  44     rtx GTY ((tag ("false"))) r;
  45   } GTY ((desc ("current_ir_type () == IR_GIMPLE"))) insns;
  46
  47   /* Auxiliary info specific to a pass.  */
  48   PTR GTY ((skip (""))) aux;
  49
  50   /* Location of any goto implicit in the edge and associated BLOCK.  */
  51   tree goto_block;
  52   location_t goto_locus;
  53
  54   /* The index number corresponding to this edge in the edge vector
  55      dest->preds.  */
  56   unsigned int dest_idx;
  57
  58   int flags;                    /* see EDGE_* below  */
  59   int probability;              /* biased by REG_BR_PROB_BASE */
  60   gcov_type count;              /* Expected number of executions calculated
  61                                    in profile.c  */
  62 };
  63
  64 DEF_VEC_P(edge);
  65 DEF_VEC_ALLOC_P(edge,gc);
  66 DEF_VEC_ALLOC_P(edge,heap);
  67
  68 /* Always update the table in cfg.c dump_edge_info.  */
  69 #define EDGE_FALLTHRU           0x0001  /* 'Straight line' flow */
  70 #define EDGE_ABNORMAL           0x0002  /* Strange flow, like computed
  71                                            label, or eh */
  72 #define EDGE_ABNORMAL_CALL      0x0004  /* Call with abnormal exit
  73                                            like an exception, or sibcall */
  74 #define EDGE_EH                 0x0008  /* Exception throw */
  75 #define EDGE_FAKE               0x0010  /* Not a real edge (profile.c) */
  76 #define EDGE_DFS_BACK           0x0020  /* A backwards edge */
  77 #define EDGE_CAN_FALLTHRU       0x0040  /* Candidate for straight line
  78                                            flow.  */
  79 #define EDGE_IRREDUCIBLE_LOOP   0x0080  /* Part of irreducible loop.  */
  80 #define EDGE_SIBCALL            0x0100  /* Edge from sibcall to exit.  */
  81 #define EDGE_LOOP_EXIT          0x0200  /* Exit of a loop.  */
  82 #define EDGE_TRUE_VALUE         0x0400  /* Edge taken when controlling
  83                                            predicate is nonzero.  */
  84 #define EDGE_FALSE_VALUE        0x0800  /* Edge taken when controlling
  85                                            predicate is zero.  */
  86 #define EDGE_EXECUTABLE         0x1000  /* Edge is executable.  Only
  87                                            valid during SSA-CCP.  */
  88 #define EDGE_CROSSING           0x2000  /* Edge crosses between hot
  89                                            and cold sections, when we
  90                                            do partitioning.  */
  91 #define EDGE_PRESERVE           0x4000  /* Never merge blocks via this edge. */
  92 #define EDGE_ALL_FLAGS          0x7fff
  93
  94 #define EDGE_COMPLEX \
  95   (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH | EDGE_PRESERVE)
  96
  97 /* Counter summary from the last set of coverage counts read by
  98    profile.c.  */
  99 extern const struct gcov_ctr_summary *profile_info;
 100
 101 /* Declared in cfgloop.h.  */
 102 struct loop;
 103
 104 struct GTY(()) rtl_bb_info {
 105   /* The first insn of the block is embedded into bb->il.x.  */
 106   /* The last insn of the block.  */
 107   rtx end_;
 108
 109   /* In CFGlayout mode points to insn notes/jumptables to be placed just before
 110      and after the block.   */
 111   rtx header_;
 112   rtx footer_;
 113 };
 114
 115 struct GTY(()) gimple_bb_info {
 116   /* Sequence of statements in this block.  */
 117   gimple_seq seq;
 118
 119   /* PHI nodes for this block.  */
 120   gimple_seq phi_nodes;
 121 };
 122
 123 /* A basic block is a sequence of instructions with only entry and
 124    only one exit.  If any one of the instructions are executed, they
 125    will all be executed, and in sequence from first to last.
 126
 127    There may be COND_EXEC instructions in the basic block.  The
 128    COND_EXEC *instructions* will be executed -- but if the condition
 129    is false the conditionally executed *expressions* will of course
 130    not be executed.  We don't consider the conditionally executed
 131    expression (which might have side-effects) to be in a separate
 132    basic block because the program counter will always be at the same
 133    location after the COND_EXEC instruction, regardless of whether the
 134    condition is true or not.
 135
 136    Basic blocks need not start with a label nor end with a jump insn.
 137    For example, a previous basic block may just "conditionally fall"
 138    into the succeeding basic block, and the last basic block need not
 139    end with a jump insn.  Block 0 is a descendant of the entry block.
 140
 141    A basic block beginning with two labels cannot have notes between
 142    the labels.
 143
 144    Data for jump tables are stored in jump_insns that occur in no
 145    basic block even though these insns can follow or precede insns in
 146    basic blocks.  */
 147
 148 /* Basic block information indexed by block number.  */
 149 struct GTY((chain_next ("%h.next_bb"), chain_prev ("%h.prev_bb"))) basic_block_def {
 150   /* The edges into and out of the block.  */
 151   VEC(edge,gc) *preds;
 152   VEC(edge,gc) *succs;
 153
 154   /* Auxiliary info specific to a pass.  */
 155   PTR GTY ((skip (""))) aux;
 156
 157   /* Innermost loop containing the block.  */
 158   struct loop *loop_father;
 159
 160   /* The dominance and postdominance information node.  */
 161   struct et_node * GTY ((skip (""))) dom[2];
 162
 163   /* Previous and next blocks in the chain.  */
 164   struct basic_block_def *prev_bb;
 165   struct basic_block_def *next_bb;
 166
 167   union basic_block_il_dependent {
 168       struct gimple_bb_info GTY ((tag ("0"))) gimple;
 169       struct {
 170         rtx head_;
 171         struct rtl_bb_info * rtl;
 172       } GTY ((tag ("1"))) x;
 173     } GTY ((desc ("((%1.flags & BB_RTL) != 0)"))) il;
 174
 175   /* Expected number of executions: calculated in profile.c.  */
 176   gcov_type count;
 177
 178   /* The index of this block.  */
 179   int index;
 180
 181   /* The loop depth of this block.  */
 182   int loop_depth;
 183
 184   /* Expected frequency.  Normalized to be in range 0 to BB_FREQ_MAX.  */
 185   int frequency;
 186
 187   /* The discriminator for this block.  */
 188   int discriminator;
 189
 190   /* Various flags.  See BB_* below.  */
 191   int flags;
 192 };
 193
 194 /* This ensures that struct gimple_bb_info is smaller than
 195    struct rtl_bb_info, so that inlining the former into basic_block_def
 196    is the better choice.  */
 197 typedef int __assert_gimple_bb_smaller_rtl_bb
 198               [(int)sizeof(struct rtl_bb_info)
 199                - (int)sizeof (struct gimple_bb_info)];
 200
 201 DEF_VEC_P(basic_block);
 202 DEF_VEC_ALLOC_P(basic_block,gc);
 203 DEF_VEC_ALLOC_P(basic_block,heap);
 204
 205 #define BB_FREQ_MAX 10000
 206
 207 /* Masks for basic_block.flags.
 208
 209    BB_HOT_PARTITION and BB_COLD_PARTITION should be preserved throughout
 210    the compilation, so they are never cleared.
 211
 212    All other flags may be cleared by clear_bb_flags().  It is generally
 213    a bad idea to rely on any flags being up-to-date.
 214
 215    Always update the table in cfg.c dump_bb_info.  */
 216
 217 enum bb_flags
 218 {
 219   /* Only set on blocks that have just been created by create_bb.  */
 220   BB_NEW = 1 << 0,
 221
 222   /* Set by find_unreachable_blocks.  Do not rely on this being set in any
 223      pass.  */
 224   BB_REACHABLE = 1 << 1,
 225
 226   /* Set for blocks in an irreducible loop by loop analysis.  */
 227   BB_IRREDUCIBLE_LOOP = 1 << 2,
 228
 229   /* Set on blocks that may actually not be single-entry single-exit block.  */
 230   BB_SUPERBLOCK = 1 << 3,
 231
 232   /* Set on basic blocks that the scheduler should not touch.  This is used
 233      by SMS to prevent other schedulers from messing with the loop schedule.  */
 234   BB_DISABLE_SCHEDULE = 1 << 4,
 235
 236   /* Set on blocks that should be put in a hot section.  */
 237   BB_HOT_PARTITION = 1 << 5,
 238
 239   /* Set on blocks that should be put in a cold section.  */
 240   BB_COLD_PARTITION = 1 << 6,
 241
 242   /* Set on block that was duplicated.  */
 243   BB_DUPLICATED = 1 << 7,
 244
 245   /* Set if the label at the top of this block is the target of a non-local goto.  */
 246   BB_NON_LOCAL_GOTO_TARGET = 1 << 8,
 247
 248   /* Set on blocks that are in RTL format.  */
 249   BB_RTL = 1 << 9 ,
 250
 251   /* Set on blocks that are forwarder blocks.
 252      Only used in cfgcleanup.c.  */
 253   BB_FORWARDER_BLOCK = 1 << 10,
 254
 255   /* Set on blocks that cannot be threaded through.
 256      Only used in cfgcleanup.c.  */
 257   BB_NONTHREADABLE_BLOCK = 1 << 11,
 258
 259   /* Set on blocks that were modified in some way.  This bit is set in
 260      df_set_bb_dirty, but not cleared by df_analyze, so it can be used
 261      to test whether a block has been modified prior to a df_analyze
 262      call.  */
 263   BB_MODIFIED = 1 << 12,
 264
 265   /* A general visited flag for passes to use.  */
 266   BB_VISITED = 1 << 13,
 267
 268   /* Set on blocks that are in a transaction.  This is calculated on
 269      demand, and is available after calling
 270      compute_transaction_bits().  */
 271   BB_IN_TRANSACTION = 1 << 14
 272 };
 273
 274 /* Dummy flag for convenience in the hot/cold partitioning code.  */
 275 #define BB_UNPARTITIONED        0
 276
 277 /* Partitions, to be used when partitioning hot and cold basic blocks into
 278    separate sections.  */
 279 #define BB_PARTITION(bb) ((bb)->flags & (BB_HOT_PARTITION|BB_COLD_PARTITION))
 280 #define BB_SET_PARTITION(bb, part) do {                                 \
 281   basic_block bb_ = (bb);                                               \
 282   bb_->flags = ((bb_->flags & ~(BB_HOT_PARTITION|BB_COLD_PARTITION))    \
 283                 | (part));                                              \
 284 } while (0)
 285
 286 #define BB_COPY_PARTITION(dstbb, srcbb) \
 287   BB_SET_PARTITION (dstbb, BB_PARTITION (srcbb))
 288
 289 /* State of dominance information.  */
 290
 291 enum dom_state
 292 {
 293   DOM_NONE,             /* Not computed at all.  */
 294   DOM_NO_FAST_QUERY,    /* The data is OK, but the fast query data are not usable.  */
 295   DOM_OK                /* Everything is ok.  */
 296 };
 297
 298 /* What sort of profiling information we have.  */
 299 enum profile_status_d
 300 {
 301   PROFILE_ABSENT,
 302   PROFILE_GUESSED,
 303   PROFILE_READ,
 304   PROFILE_LAST  /* Last value, used by profile streaming.  */
 305 };
 306
 307 /* A structure to group all the per-function control flow graph data.
 308    The x_* prefixing is necessary because otherwise references to the
 309    fields of this struct are interpreted as the defines for backward
 310    source compatibility following the definition of this struct.  */
 311 struct GTY(()) control_flow_graph {
 312   /* Block pointers for the exit and entry of a function.
 313      These are always the head and tail of the basic block list.  */
 314   basic_block x_entry_block_ptr;
 315   basic_block x_exit_block_ptr;
 316
 317   /* Index by basic block number, get basic block struct info.  */
 318   VEC(basic_block,gc) *x_basic_block_info;
 319
 320   /* Number of basic blocks in this flow graph.  */
 321   int x_n_basic_blocks;
 322
 323   /* Number of edges in this flow graph.  */
 324   int x_n_edges;
 325
 326   /* The first free basic block number.  */
 327   int x_last_basic_block;
 328
 329   /* UIDs for LABEL_DECLs.  */
 330   int last_label_uid;
 331
 332   /* Mapping of labels to their associated blocks.  At present
 333      only used for the gimple CFG.  */
 334   VEC(basic_block,gc) *x_label_to_block_map;
 335
 336   enum profile_status_d x_profile_status;
 337
 338   /* Whether the dominators and the postdominators are available.  */
 339   enum dom_state x_dom_computed[2];
 340
 341   /* Number of basic blocks in the dominance tree.  */
 342   unsigned x_n_bbs_in_dom_tree[2];
 343
 344   /* Maximal number of entities in the single jumptable.  Used to estimate
 345      final flowgraph size.  */
 346   int max_jumptable_ents;
 347 };
 348
 349 /* Defines for accessing the fields of the CFG structure for function FN.  */
 350 #define ENTRY_BLOCK_PTR_FOR_FUNCTION(FN)     ((FN)->cfg->x_entry_block_ptr)
 351 #define EXIT_BLOCK_PTR_FOR_FUNCTION(FN)      ((FN)->cfg->x_exit_block_ptr)
 352 #define basic_block_info_for_function(FN)    ((FN)->cfg->x_basic_block_info)
 353 #define n_basic_blocks_for_function(FN)      ((FN)->cfg->x_n_basic_blocks)
 354 #define n_edges_for_function(FN)             ((FN)->cfg->x_n_edges)
 355 #define last_basic_block_for_function(FN)    ((FN)->cfg->x_last_basic_block)
 356 #define label_to_block_map_for_function(FN)  ((FN)->cfg->x_label_to_block_map)
 357 #define profile_status_for_function(FN)      ((FN)->cfg->x_profile_status)
 358
 359 #define BASIC_BLOCK_FOR_FUNCTION(FN,N) \
 360   (VEC_index (basic_block, basic_block_info_for_function(FN), (N)))
 361 #define SET_BASIC_BLOCK_FOR_FUNCTION(FN,N,BB) \
 362   (VEC_replace (basic_block, basic_block_info_for_function(FN), (N), (BB)))
 363
 364 /* Defines for textual backward source compatibility.  */
 365 #define ENTRY_BLOCK_PTR         (cfun->cfg->x_entry_block_ptr)
 366 #define EXIT_BLOCK_PTR          (cfun->cfg->x_exit_block_ptr)
 367 #define basic_block_info        (cfun->cfg->x_basic_block_info)
 368 #define n_basic_blocks          (cfun->cfg->x_n_basic_blocks)
 369 #define n_edges                 (cfun->cfg->x_n_edges)
 370 #define last_basic_block        (cfun->cfg->x_last_basic_block)
 371 #define label_to_block_map      (cfun->cfg->x_label_to_block_map)
 372 #define profile_status          (cfun->cfg->x_profile_status)
 373
 374 #define BASIC_BLOCK(N)          (VEC_index (basic_block, basic_block_info, (N)))
 375 #define SET_BASIC_BLOCK(N,BB)   (VEC_replace (basic_block, basic_block_info, (N), (BB)))
 376
 377 /* For iterating over basic blocks.  */
 378 #define FOR_BB_BETWEEN(BB, FROM, TO, DIR) \
 379   for (BB = FROM; BB != TO; BB = BB->DIR)
 380
 381 #define FOR_EACH_BB_FN(BB, FN) \
 382   FOR_BB_BETWEEN (BB, (FN)->cfg->x_entry_block_ptr->next_bb, (FN)->cfg->x_exit_block_ptr, next_bb)
 383
 384 #define FOR_EACH_BB(BB) FOR_EACH_BB_FN (BB, cfun)
 385
 386 #define FOR_EACH_BB_REVERSE_FN(BB, FN) \
 387   FOR_BB_BETWEEN (BB, (FN)->cfg->x_exit_block_ptr->prev_bb, (FN)->cfg->x_entry_block_ptr, prev_bb)
 388
 389 #define FOR_EACH_BB_REVERSE(BB) FOR_EACH_BB_REVERSE_FN(BB, cfun)
 390
 391 /* For iterating over insns in basic block.  */
 392 #define FOR_BB_INSNS(BB, INSN)                  \
 393   for ((INSN) = BB_HEAD (BB);                   \
 394        (INSN) && (INSN) != NEXT_INSN (BB_END (BB));     \
 395        (INSN) = NEXT_INSN (INSN))
 396
 397 /* For iterating over insns in basic block when we might remove the
 398    current insn.  */
 399 #define FOR_BB_INSNS_SAFE(BB, INSN, CURR)                       \
 400   for ((INSN) = BB_HEAD (BB), (CURR) = (INSN) ? NEXT_INSN ((INSN)): NULL;       \
 401        (INSN) && (INSN) != NEXT_INSN (BB_END (BB));     \
 402        (INSN) = (CURR), (CURR) = (INSN) ? NEXT_INSN ((INSN)) : NULL)
 403
 404 #define FOR_BB_INSNS_REVERSE(BB, INSN)          \
 405   for ((INSN) = BB_END (BB);                    \
 406        (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));    \
 407        (INSN) = PREV_INSN (INSN))
 408
 409 #define FOR_BB_INSNS_REVERSE_SAFE(BB, INSN, CURR)       \
 410   for ((INSN) = BB_END (BB),(CURR) = (INSN) ? PREV_INSN ((INSN)) : NULL;        \
 411        (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));    \
 412        (INSN) = (CURR), (CURR) = (INSN) ? PREV_INSN ((INSN)) : NULL)
 413
 414 /* Cycles through _all_ basic blocks, even the fake ones (entry and
 415    exit block).  */
 416
 417 #define FOR_ALL_BB(BB) \
 418   for (BB = ENTRY_BLOCK_PTR; BB; BB = BB->next_bb)
 419
 420 #define FOR_ALL_BB_FN(BB, FN) \
 421   for (BB = ENTRY_BLOCK_PTR_FOR_FUNCTION (FN); BB; BB = BB->next_bb)
 422
 423 \f
 424 /* Stuff for recording basic block info.  */
 425
 426 #define BB_HEAD(B)      (B)->il.x.head_
 427 #define BB_END(B)       (B)->il.x.rtl->end_
 428 #define BB_HEADER(B)    (B)->il.x.rtl->header_
 429 #define BB_FOOTER(B)    (B)->il.x.rtl->footer_
 430
 431 /* Special block numbers [markers] for entry and exit.
 432    Neither of them is supposed to hold actual statements.  */
 433 #define ENTRY_BLOCK (0)
 434 #define EXIT_BLOCK (1)
 435
 436 /* The two blocks that are always in the cfg.  */
 437 #define NUM_FIXED_BLOCKS (2)
 438
 439 #define set_block_for_insn(INSN, BB)  (BLOCK_FOR_INSN (INSN) = BB)
 440
 441 extern void compute_bb_for_insn (void);
 442 extern unsigned int free_bb_for_insn (void);
 443 extern void update_bb_for_insn (basic_block);
 444
 445 extern void insert_insn_on_edge (rtx, edge);
 446 basic_block split_edge_and_insert (edge, rtx);
 447
 448 extern void commit_one_edge_insertion (edge e);
 449 extern void commit_edge_insertions (void);
 450
 451 extern void remove_fake_edges (void);
 452 extern void remove_fake_exit_edges (void);
 453 extern void add_noreturn_fake_exit_edges (void);
 454 extern void connect_infinite_loops_to_exit (void);
 455 extern edge unchecked_make_edge (basic_block, basic_block, int);
 456 extern edge cached_make_edge (sbitmap, basic_block, basic_block, int);
 457 extern edge make_edge (basic_block, basic_block, int);
 458 extern edge make_single_succ_edge (basic_block, basic_block, int);
 459 extern void remove_edge_raw (edge);
 460 extern void redirect_edge_succ (edge, basic_block);
 461 extern edge redirect_edge_succ_nodup (edge, basic_block);
 462 extern void redirect_edge_pred (edge, basic_block);
 463 extern basic_block create_basic_block_structure (rtx, rtx, rtx, basic_block);
 464 extern void clear_bb_flags (void);
 465 extern int post_order_compute (int *, bool, bool);
 466 extern int inverted_post_order_compute (int *);
 467 extern int pre_and_rev_post_order_compute (int *, int *, bool);
 468 extern int dfs_enumerate_from (basic_block, int,
 469                                bool (*)(const_basic_block, const void *),
 470                                basic_block *, int, const void *);
 471 extern void compute_dominance_frontiers (struct bitmap_head_def *);
 472 extern bitmap compute_idf (bitmap, struct bitmap_head_def *);
 473 extern void dump_bb_info (basic_block, bool, bool, int, const char *, FILE *);
 474 extern void dump_edge_info (FILE *, edge, int);
 475 extern void brief_dump_cfg (FILE *);
 476 extern void clear_edges (void);
 477 extern void scale_bbs_frequencies_int (basic_block *, int, int, int);
 478 extern void scale_bbs_frequencies_gcov_type (basic_block *, int, gcov_type,
 479                                              gcov_type);
 480
 481 /* Structure to group all of the information to process IF-THEN and
 482    IF-THEN-ELSE blocks for the conditional execution support.  This
 483    needs to be in a public file in case the IFCVT macros call
 484    functions passing the ce_if_block data structure.  */
 485
 486 typedef struct ce_if_block
 487 {
 488   basic_block test_bb;                  /* First test block.  */
 489   basic_block then_bb;                  /* THEN block.  */
 490   basic_block else_bb;                  /* ELSE block or NULL.  */
 491   basic_block join_bb;                  /* Join THEN/ELSE blocks.  */
 492   basic_block last_test_bb;             /* Last bb to hold && or || tests.  */
 493   int num_multiple_test_blocks;         /* # of && and || basic blocks.  */
 494   int num_and_and_blocks;               /* # of && blocks.  */
 495   int num_or_or_blocks;                 /* # of || blocks.  */
 496   int num_multiple_test_insns;          /* # of insns in && and || blocks.  */
 497   int and_and_p;                        /* Complex test is &&.  */
 498   int num_then_insns;                   /* # of insns in THEN block.  */
 499   int num_else_insns;                   /* # of insns in ELSE block.  */
 500   int pass;                             /* Pass number.  */
 501
 502 #ifdef IFCVT_EXTRA_FIELDS
 503   IFCVT_EXTRA_FIELDS                    /* Any machine dependent fields.  */
 504 #endif
 505
 506 } ce_if_block_t;
 507
 508 /* This structure maintains an edge list vector.  */
 509 struct edge_list
 510 {
 511   int num_blocks;
 512   int num_edges;
 513   edge *index_to_edge;
 514 };
 515
 516 /* The base value for branch probability notes and edge probabilities.  */
 517 #define REG_BR_PROB_BASE  10000
 518
 519 /* This is the value which indicates no edge is present.  */
 520 #define EDGE_INDEX_NO_EDGE      -1
 521
 522 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 523    if there is no edge between the 2 basic blocks.  */
 524 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 525
 526 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 527    block which is either the pred or succ end of the indexed edge.  */
 528 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 529 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 530
 531 /* INDEX_EDGE returns a pointer to the edge.  */
 532 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 533
 534 /* Number of edges in the compressed edge list.  */
 535 #define NUM_EDGES(el)                   ((el)->num_edges)
 536
 537 /* BB is assumed to contain conditional jump.  Return the fallthru edge.  */
 538 #define FALLTHRU_EDGE(bb)               (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
 539                                          ? EDGE_SUCC ((bb), 0) : EDGE_SUCC ((bb), 1))
 540
 541 /* BB is assumed to contain conditional jump.  Return the branch edge.  */
 542 #define BRANCH_EDGE(bb)                 (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
 543                                          ? EDGE_SUCC ((bb), 1) : EDGE_SUCC ((bb), 0))
 544
 545 /* Return expected execution frequency of the edge E.  */
 546 #define EDGE_FREQUENCY(e)               (((e)->src->frequency \
 547                                           * (e)->probability \
 548                                           + REG_BR_PROB_BASE / 2) \
 549                                          / REG_BR_PROB_BASE)
 550
 551 /* Return nonzero if edge is critical.  */
 552 #define EDGE_CRITICAL_P(e)              (EDGE_COUNT ((e)->src->succs) >= 2 \
 553                                          && EDGE_COUNT ((e)->dest->preds) >= 2)
 554
 555 #define EDGE_COUNT(ev)                  VEC_length (edge, (ev))
 556 #define EDGE_I(ev,i)                    VEC_index  (edge, (ev), (i))
 557 #define EDGE_PRED(bb,i)                 VEC_index  (edge, (bb)->preds, (i))
 558 #define EDGE_SUCC(bb,i)                 VEC_index  (edge, (bb)->succs, (i))
 559
 560 /* Returns true if BB has precisely one successor.  */
 561
 562 static inline bool
 563 single_succ_p (const_basic_block bb)
 564 {
 565   return EDGE_COUNT (bb->succs) == 1;
 566 }
 567
 568 /* Returns true if BB has precisely one predecessor.  */
 569
 570 static inline bool
 571 single_pred_p (const_basic_block bb)
 572 {
 573   return EDGE_COUNT (bb->preds) == 1;
 574 }
 575
 576 /* Returns the single successor edge of basic block BB.  Aborts if
 577    BB does not have exactly one successor.  */
 578
 579 static inline edge
 580 single_succ_edge (const_basic_block bb)
 581 {
 582   gcc_checking_assert (single_succ_p (bb));
 583   return EDGE_SUCC (bb, 0);
 584 }
 585
 586 /* Returns the single predecessor edge of basic block BB.  Aborts
 587    if BB does not have exactly one predecessor.  */
 588
 589 static inline edge
 590 single_pred_edge (const_basic_block bb)
 591 {
 592   gcc_checking_assert (single_pred_p (bb));
 593   return EDGE_PRED (bb, 0);
 594 }
 595
 596 /* Returns the single successor block of basic block BB.  Aborts
 597    if BB does not have exactly one successor.  */
 598
 599 static inline basic_block
 600 single_succ (const_basic_block bb)
 601 {
 602   return single_succ_edge (bb)->dest;
 603 }
 604
 605 /* Returns the single predecessor block of basic block BB.  Aborts
 606    if BB does not have exactly one predecessor.*/
 607
 608 static inline basic_block
 609 single_pred (const_basic_block bb)
 610 {
 611   return single_pred_edge (bb)->src;
 612 }
 613
 614 /* Iterator object for edges.  */
 615
 616 typedef struct {
 617   unsigned index;
 618   VEC(edge,gc) **container;
 619 } edge_iterator;
 620
 621 static inline VEC(edge,gc) *
 622 ei_container (edge_iterator i)
 623 {
 624   gcc_checking_assert (i.container);
 625   return *i.container;
 626 }
 627
 628 #define ei_start(iter) ei_start_1 (&(iter))
 629 #define ei_last(iter) ei_last_1 (&(iter))
 630
 631 /* Return an iterator pointing to the start of an edge vector.  */
 632 static inline edge_iterator
 633 ei_start_1 (VEC(edge,gc) **ev)
 634 {
 635   edge_iterator i;
 636
 637   i.index = 0;
 638   i.container = ev;
 639
 640   return i;
 641 }
 642
 643 /* Return an iterator pointing to the last element of an edge
 644    vector.  */
 645 static inline edge_iterator
 646 ei_last_1 (VEC(edge,gc) **ev)
 647 {
 648   edge_iterator i;
 649
 650   i.index = EDGE_COUNT (*ev) - 1;
 651   i.container = ev;
 652
 653   return i;
 654 }
 655
 656 /* Is the iterator `i' at the end of the sequence?  */
 657 static inline bool
 658 ei_end_p (edge_iterator i)
 659 {
 660   return (i.index == EDGE_COUNT (ei_container (i)));
 661 }
 662
 663 /* Is the iterator `i' at one position before the end of the
 664    sequence?  */
 665 static inline bool
 666 ei_one_before_end_p (edge_iterator i)
 667 {
 668   return (i.index + 1 == EDGE_COUNT (ei_container (i)));
 669 }
 670
 671 /* Advance the iterator to the next element.  */
 672 static inline void
 673 ei_next (edge_iterator *i)
 674 {
 675   gcc_checking_assert (i->index < EDGE_COUNT (ei_container (*i)));
 676   i->index++;
 677 }
 678
 679 /* Move the iterator to the previous element.  */
 680 static inline void
 681 ei_prev (edge_iterator *i)
 682 {
 683   gcc_checking_assert (i->index > 0);
 684   i->index--;
 685 }
 686
 687 /* Return the edge pointed to by the iterator `i'.  */
 688 static inline edge
 689 ei_edge (edge_iterator i)
 690 {
 691   return EDGE_I (ei_container (i), i.index);
 692 }
 693
 694 /* Return an edge pointed to by the iterator.  Do it safely so that
 695    NULL is returned when the iterator is pointing at the end of the
 696    sequence.  */
 697 static inline edge
 698 ei_safe_edge (edge_iterator i)
 699 {
 700   return !ei_end_p (i) ? ei_edge (i) : NULL;
 701 }
 702
 703 /* Return 1 if we should continue to iterate.  Return 0 otherwise.
 704    *Edge P is set to the next edge if we are to continue to iterate
 705    and NULL otherwise.  */
 706
 707 static inline bool
 708 ei_cond (edge_iterator ei, edge *p)
 709 {
 710   if (!ei_end_p (ei))
 711     {
 712       *p = ei_edge (ei);
 713       return 1;
 714     }
 715   else
 716     {
 717       *p = NULL;
 718       return 0;
 719     }
 720 }
 721
 722 /* This macro serves as a convenient way to iterate each edge in a
 723    vector of predecessor or successor edges.  It must not be used when
 724    an element might be removed during the traversal, otherwise
 725    elements will be missed.  Instead, use a for-loop like that shown
 726    in the following pseudo-code:
 727
 728    FOR (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
 729      {
 730         IF (e != taken_edge)
 731           remove_edge (e);
 732         ELSE
 733           ei_next (&ei);
 734      }
 735 */
 736
 737 #define FOR_EACH_EDGE(EDGE,ITER,EDGE_VEC)       \
 738   for ((ITER) = ei_start ((EDGE_VEC));          \
 739        ei_cond ((ITER), &(EDGE));               \
 740        ei_next (&(ITER)))
 741
 742 struct edge_list * create_edge_list (void);
 743 void free_edge_list (struct edge_list *);
 744 void print_edge_list (FILE *, struct edge_list *);
 745 void verify_edge_list (FILE *, struct edge_list *);
 746 int find_edge_index (struct edge_list *, basic_block, basic_block);
 747 edge find_edge (basic_block, basic_block);
 748
 749 #define CLEANUP_EXPENSIVE       1       /* Do relatively expensive optimizations
 750                                            except for edge forwarding */
 751 #define CLEANUP_CROSSJUMP       2       /* Do crossjumping.  */
 752 #define CLEANUP_POST_REGSTACK   4       /* We run after reg-stack and need
 753                                            to care REG_DEAD notes.  */
 754 #define CLEANUP_THREADING       8       /* Do jump threading.  */
 755 #define CLEANUP_NO_INSN_DEL     16      /* Do not try to delete trivially dead
 756                                            insns.  */
 757 #define CLEANUP_CFGLAYOUT       32      /* Do cleanup in cfglayout mode.  */
 758 #define CLEANUP_CFG_CHANGED     64      /* The caller changed the CFG.  */
 759
 760 /* In lcm.c */
 761 extern struct edge_list *pre_edge_lcm (int, sbitmap *, sbitmap *,
 762                                        sbitmap *, sbitmap *, sbitmap **,
 763                                        sbitmap **);
 764 extern struct edge_list *pre_edge_rev_lcm (int, sbitmap *,
 765                                            sbitmap *, sbitmap *,
 766                                            sbitmap *, sbitmap **,
 767                                            sbitmap **);
 768 extern void compute_available (sbitmap *, sbitmap *, sbitmap *, sbitmap *);
 769
 770 /* In predict.c */
 771 extern bool maybe_hot_bb_p (const_basic_block);
 772 extern bool maybe_hot_edge_p (edge);
 773 extern bool probably_never_executed_bb_p (const_basic_block);
 774 extern bool optimize_bb_for_size_p (const_basic_block);
 775 extern bool optimize_bb_for_speed_p (const_basic_block);
 776 extern bool optimize_edge_for_size_p (edge);
 777 extern bool optimize_edge_for_speed_p (edge);
 778 extern bool optimize_loop_for_size_p (struct loop *);
 779 extern bool optimize_loop_for_speed_p (struct loop *);
 780 extern bool optimize_loop_nest_for_size_p (struct loop *);
 781 extern bool optimize_loop_nest_for_speed_p (struct loop *);
 782 extern bool gimple_predicted_by_p (const_basic_block, enum br_predictor);
 783 extern bool rtl_predicted_by_p (const_basic_block, enum br_predictor);
 784 extern void gimple_predict_edge (edge, enum br_predictor, int);
 785 extern void rtl_predict_edge (edge, enum br_predictor, int);
 786 extern void predict_edge_def (edge, enum br_predictor, enum prediction);
 787 extern void guess_outgoing_edge_probabilities (basic_block);
 788 extern void remove_predictions_associated_with_edge (edge);
 789 extern bool edge_probability_reliable_p (const_edge);
 790 extern bool br_prob_note_reliable_p (const_rtx);
 791 extern bool predictable_edge_p (edge);
 792
 793 /* In cfg.c  */
 794 extern void init_flow (struct function *);
 795 extern void debug_bb (basic_block);
 796 extern basic_block debug_bb_n (int);
 797 extern void expunge_block (basic_block);
 798 extern void link_block (basic_block, basic_block);
 799 extern void unlink_block (basic_block);
 800 extern void compact_blocks (void);
 801 extern basic_block alloc_block (void);
 802 extern void alloc_aux_for_blocks (int);
 803 extern void clear_aux_for_blocks (void);
 804 extern void free_aux_for_blocks (void);
 805 extern void alloc_aux_for_edge (edge, int);
 806 extern void alloc_aux_for_edges (int);
 807 extern void clear_aux_for_edges (void);
 808 extern void free_aux_for_edges (void);
 809
 810 /* In cfganal.c  */
 811 extern void find_unreachable_blocks (void);
 812 extern bool forwarder_block_p (const_basic_block);
 813 extern bool can_fallthru (basic_block, basic_block);
 814 extern bool could_fall_through (basic_block, basic_block);
 815 extern void flow_nodes_print (const char *, const_sbitmap, FILE *);
 816 extern void flow_edge_list_print (const char *, const edge *, int, FILE *);
 817
 818 /* In cfgrtl.c  */
 819 extern rtx block_label (basic_block);
 820 extern rtx bb_note (basic_block);
 821 extern bool purge_all_dead_edges (void);
 822 extern bool purge_dead_edges (basic_block);
 823 extern bool fixup_abnormal_edges (void);
 824 extern basic_block force_nonfallthru_and_redirect (edge, basic_block, rtx);
 825
 826 /* In cfgbuild.c.  */
 827 extern void find_many_sub_basic_blocks (sbitmap);
 828 extern void rtl_make_eh_edge (sbitmap, basic_block, rtx);
 829
 830 enum replace_direction { dir_none, dir_forward, dir_backward, dir_both };
 831
 832 /* In cfgcleanup.c.  */
 833 extern bool cleanup_cfg (int);
 834 extern int flow_find_cross_jump (basic_block, basic_block, rtx *, rtx *,
 835                                  enum replace_direction*);
 836 extern int flow_find_head_matching_sequence (basic_block, basic_block,
 837                                              rtx *, rtx *, int);
 838
 839 extern bool delete_unreachable_blocks (void);
 840
 841 extern bool mark_dfs_back_edges (void);
 842 extern void set_edge_can_fallthru_flag (void);
 843 extern void update_br_prob_note (basic_block);
 844 extern bool inside_basic_block_p (const_rtx);
 845 extern bool control_flow_insn_p (const_rtx);
 846 extern rtx get_last_bb_insn (basic_block);
 847
 848 /* In dominance.c */
 849
 850 enum cdi_direction
 851 {
 852   CDI_DOMINATORS = 1,
 853   CDI_POST_DOMINATORS = 2
 854 };
 855
 856 extern enum dom_state dom_info_state (enum cdi_direction);
 857 extern void set_dom_info_availability (enum cdi_direction, enum dom_state);
 858 extern bool dom_info_available_p (enum cdi_direction);
 859 extern void calculate_dominance_info (enum cdi_direction);
 860 extern void free_dominance_info (enum cdi_direction);
 861 extern basic_block nearest_common_dominator (enum cdi_direction,
 862                                              basic_block, basic_block);
 863 extern basic_block nearest_common_dominator_for_set (enum cdi_direction,
 864                                                      bitmap);
 865 extern void set_immediate_dominator (enum cdi_direction, basic_block,
 866                                      basic_block);
 867 extern basic_block get_immediate_dominator (enum cdi_direction, basic_block);
 868 extern bool dominated_by_p (enum cdi_direction, const_basic_block, const_basic_block);
 869 extern VEC (basic_block, heap) *get_dominated_by (enum cdi_direction, basic_block);
 870 extern VEC (basic_block, heap) *get_dominated_by_region (enum cdi_direction,
 871                                                          basic_block *,
 872                                                          unsigned);
 873 extern VEC (basic_block, heap) *get_dominated_to_depth (enum cdi_direction,
 874                                                         basic_block, int);
 875 extern VEC (basic_block, heap) *get_all_dominated_blocks (enum cdi_direction,
 876                                                           basic_block);
 877 extern void add_to_dominance_info (enum cdi_direction, basic_block);
 878 extern void delete_from_dominance_info (enum cdi_direction, basic_block);
 879 basic_block recompute_dominator (enum cdi_direction, basic_block);
 880 extern void redirect_immediate_dominators (enum cdi_direction, basic_block,
 881                                            basic_block);
 882 extern void iterate_fix_dominators (enum cdi_direction,
 883                                     VEC (basic_block, heap) *, bool);
 884 extern void verify_dominators (enum cdi_direction);
 885 extern basic_block first_dom_son (enum cdi_direction, basic_block);
 886 extern basic_block next_dom_son (enum cdi_direction, basic_block);
 887 unsigned bb_dom_dfs_in (enum cdi_direction, basic_block);
 888 unsigned bb_dom_dfs_out (enum cdi_direction, basic_block);
 889
 890 extern edge try_redirect_by_replacing_jump (edge, basic_block, bool);
 891 extern void break_superblocks (void);
 892 extern void relink_block_chain (bool);
 893 extern void check_bb_profile (basic_block, FILE *);
 894 extern void update_bb_profile_for_threading (basic_block, int, gcov_type, edge);
 895 extern void init_rtl_bb_info (basic_block);
 896
 897 extern void initialize_original_copy_tables (void);
 898 extern void free_original_copy_tables (void);
 899 extern void set_bb_original (basic_block, basic_block);
 900 extern basic_block get_bb_original (basic_block);
 901 extern void set_bb_copy (basic_block, basic_block);
 902 extern basic_block get_bb_copy (basic_block);
 903 void set_loop_copy (struct loop *, struct loop *);
 904 struct loop *get_loop_copy (struct loop *);
 905
 906 #include "cfghooks.h"
 907
 908 /* Return true when one of the predecessor edges of BB is marked with EDGE_EH.  */
 909 static inline bool
 910 bb_has_eh_pred (basic_block bb)
 911 {
 912   edge e;
 913   edge_iterator ei;
 914
 915   FOR_EACH_EDGE (e, ei, bb->preds)
 916     {
 917       if (e->flags & EDGE_EH)
 918         return true;
 919     }
 920   return false;
 921 }
 922
 923 /* Return true when one of the predecessor edges of BB is marked with EDGE_ABNORMAL.  */
 924 static inline bool
 925 bb_has_abnormal_pred (basic_block bb)
 926 {
 927   edge e;
 928   edge_iterator ei;
 929
 930   FOR_EACH_EDGE (e, ei, bb->preds)
 931     {
 932       if (e->flags & EDGE_ABNORMAL)
 933         return true;
 934     }
 935   return false;
 936 }
 937
 938 /* Return the fallthru edge in EDGES if it exists, NULL otherwise.  */
 939 static inline edge
 940 find_fallthru_edge (VEC(edge,gc) *edges)
 941 {
 942   edge e;
 943   edge_iterator ei;
 944
 945   FOR_EACH_EDGE (e, ei, edges)
 946     if (e->flags & EDGE_FALLTHRU)
 947       break;
 948
 949   return e;
 950 }
 951
 952 /* In cfgloopmanip.c.  */
 953 extern edge mfb_kj_edge;
 954 extern bool mfb_keep_just (edge);
 955
 956 /* In cfgexpand.c.  */
 957 extern void rtl_profile_for_bb (basic_block);
 958 extern void rtl_profile_for_edge (edge);
 959 extern void default_rtl_profile (void);
 960
 961 #endif /* GCC_BASIC_BLOCK_H */