gcc/basic-block.h

   1 /* Define control and data flow tables, and regsets.
   2    Copyright (C) 1987, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
   3
   4 This file is part of GNU CC.
   5
   6 GNU CC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU CC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU CC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 #ifndef _BASIC_BLOCK_H
  22 #define _BASIC_BLOCK_H 1
  23
  24 #include "bitmap.h"
  25 #include "sbitmap.h"
  26 #include "varray.h"
  27 #include "partition.h"
  28
  29 /* Head of register set linked list.  */
  30 typedef bitmap_head regset_head;
  31 /* A pointer to a regset_head.  */
  32 typedef bitmap regset;
  33
  34 /* Initialize a new regset.  */
  35 #define INIT_REG_SET(HEAD) bitmap_initialize (HEAD)
  36
  37 /* Clear a register set by freeing up the linked list.  */
  38 #define CLEAR_REG_SET(HEAD) bitmap_clear (HEAD)
  39
  40 /* Copy a register set to another register set.  */
  41 #define COPY_REG_SET(TO, FROM) bitmap_copy (TO, FROM)
  42
  43 /* Compare two register sets.  */
  44 #define REG_SET_EQUAL_P(A, B) bitmap_equal_p (A, B)
  45
  46 /* `and' a register set with a second register set.  */
  47 #define AND_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_AND)
  48
  49 /* `and' the complement of a register set with a register set.  */
  50 #define AND_COMPL_REG_SET(TO, FROM) \
  51   bitmap_operation (TO, TO, FROM, BITMAP_AND_COMPL)
  52
  53 /* Inclusive or a register set with a second register set.  */
  54 #define IOR_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_IOR)
  55
  56 /* Exclusive or a register set with a second register set.  */
  57 #define XOR_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_XOR)
  58
  59 /* Or into TO the register set FROM1 `and'ed with the complement of FROM2.  */
  60 #define IOR_AND_COMPL_REG_SET(TO, FROM1, FROM2) \
  61   bitmap_ior_and_compl (TO, FROM1, FROM2)
  62
  63 /* Clear a single register in a register set.  */
  64 #define CLEAR_REGNO_REG_SET(HEAD, REG) bitmap_clear_bit (HEAD, REG)
  65
  66 /* Set a single register in a register set.  */
  67 #define SET_REGNO_REG_SET(HEAD, REG) bitmap_set_bit (HEAD, REG)
  68
  69 /* Return true if a register is set in a register set.  */
  70 #define REGNO_REG_SET_P(TO, REG) bitmap_bit_p (TO, REG)
  71
  72 /* Copy the hard registers in a register set to the hard register set.  */
  73 extern void reg_set_to_hard_reg_set PARAMS ((HARD_REG_SET *, bitmap));
  74 #define REG_SET_TO_HARD_REG_SET(TO, FROM)                               \
  75 do {                                                                    \
  76   CLEAR_HARD_REG_SET (TO);                                              \
  77   reg_set_to_hard_reg_set (&TO, FROM);                                  \
  78 } while (0)
  79
  80 /* Loop over all registers in REGSET, starting with MIN, setting REGNUM to the
  81    register number and executing CODE for all registers that are set. */
  82 #define EXECUTE_IF_SET_IN_REG_SET(REGSET, MIN, REGNUM, CODE)            \
  83   EXECUTE_IF_SET_IN_BITMAP (REGSET, MIN, REGNUM, CODE)
  84
  85 /* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
  86    REGNUM to the register number and executing CODE for all registers that are
  87    set in the first regset and not set in the second. */
  88 #define EXECUTE_IF_AND_COMPL_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, CODE) \
  89   EXECUTE_IF_AND_COMPL_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, CODE)
  90
  91 /* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
  92    REGNUM to the register number and executing CODE for all registers that are
  93    set in both regsets. */
  94 #define EXECUTE_IF_AND_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, CODE) \
  95   EXECUTE_IF_AND_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, CODE)
  96
  97 /* Allocate a register set with oballoc.  */
  98 #define OBSTACK_ALLOC_REG_SET(OBSTACK) BITMAP_OBSTACK_ALLOC (OBSTACK)
  99
 100 /* Initialize a register set.  Returns the new register set.  */
 101 #define INITIALIZE_REG_SET(HEAD) bitmap_initialize (&HEAD)
 102
 103 /* Do any cleanup needed on a regset when it is no longer used.  */
 104 #define FREE_REG_SET(REGSET) BITMAP_FREE(REGSET)
 105
 106 /* Do any one-time initializations needed for regsets.  */
 107 #define INIT_ONCE_REG_SET() BITMAP_INIT_ONCE ()
 108
 109 /* Grow any tables needed when the number of registers is calculated
 110    or extended.  For the linked list allocation, nothing needs to
 111    be done, other than zero the statistics on the first allocation.  */
 112 #define MAX_REGNO_REG_SET(NUM_REGS, NEW_P, RENUMBER_P)
 113
 114 /* Control flow edge information.  */
 115 typedef struct edge_def {
 116   /* Links through the predecessor and successor lists.  */
 117   struct edge_def *pred_next, *succ_next;
 118
 119   /* The two blocks at the ends of the edge.  */
 120   struct basic_block_def *src, *dest;
 121
 122   /* Instructions queued on the edge.  */
 123   rtx insns;
 124
 125   /* Auxiliary info specific to a pass.  */
 126   void *aux;
 127
 128   int flags;                    /* see EDGE_* below  */
 129   int probability;              /* biased by REG_BR_PROB_BASE */
 130   int count;                    /* Expected number of executions calculated
 131                                    in profile.c  */
 132 } *edge;
 133
 134 #define EDGE_FALLTHRU           1
 135 #define EDGE_CRITICAL           2
 136 #define EDGE_ABNORMAL           4
 137 #define EDGE_ABNORMAL_CALL      8
 138 #define EDGE_EH                 16
 139 #define EDGE_FAKE               32
 140
 141 #define EDGE_COMPLEX    (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH)
 142
 143
 144 /* Basic block information indexed by block number.  */
 145 typedef struct basic_block_def {
 146   /* The first and last insns of the block.  */
 147   rtx head, end;
 148
 149   /* The edges into and out of the block.  */
 150   edge pred, succ;
 151
 152   /* Liveness info.  Note that in SSA form, global_live_at_start does
 153      not reflect the use of regs in phi functions, since the liveness
 154      of these regs may depend on which edge was taken into the block.  */
 155   regset local_set;
 156   regset global_live_at_start;
 157   regset global_live_at_end;
 158
 159   /* Auxiliary info specific to a pass.  */
 160   void *aux;
 161
 162   /* The index of this block.  */
 163   int index;
 164   /* The loop depth of this block plus one.  */
 165   int loop_depth;
 166
 167   /* The active eh region before head and after end.  */
 168   int eh_beg, eh_end;
 169
 170   int count;            /* Expected number of executions: calculated in
 171                            profile.c */
 172 } *basic_block;
 173
 174 /* Number of basic blocks in the current function.  */
 175
 176 extern int n_basic_blocks;
 177
 178 /* Number of edges in the current function.  */
 179
 180 extern int n_edges;
 181
 182 /* Index by basic block number, get basic block struct info.  */
 183
 184 extern varray_type basic_block_info;
 185
 186 #define BASIC_BLOCK(N)  (VARRAY_BB (basic_block_info, (N)))
 187
 188 /* What registers are live at the setjmp call.  */
 189
 190 extern regset regs_live_at_setjmp;
 191
 192 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 193    If the value is REG_BLOCK_GLOBAL (-2),
 194    it means (REG n) is used in more than one basic block.
 195    REG_BLOCK_UNKNOWN (-1) means it hasn't been seen yet so we don't know.
 196    This information remains valid for the rest of the compilation
 197    of the current function; it is used to control register allocation.  */
 198
 199 #define REG_BLOCK_UNKNOWN -1
 200 #define REG_BLOCK_GLOBAL -2
 201
 202 #define REG_BASIC_BLOCK(N) (VARRAY_REG (reg_n_info, N)->basic_block)
 203 \f
 204 /* Stuff for recording basic block info.  */
 205
 206 #define BLOCK_HEAD(B)      (BASIC_BLOCK (B)->head)
 207 #define BLOCK_END(B)       (BASIC_BLOCK (B)->end)
 208
 209 /* Special block numbers [markers] for entry and exit.  */
 210 #define ENTRY_BLOCK (-1)
 211 #define EXIT_BLOCK (-2)
 212
 213 /* Similarly, block pointers for the edge list.  */
 214 extern struct basic_block_def entry_exit_blocks[2];
 215 #define ENTRY_BLOCK_PTR (&entry_exit_blocks[0])
 216 #define EXIT_BLOCK_PTR  (&entry_exit_blocks[1])
 217
 218 extern varray_type basic_block_for_insn;
 219 #define BLOCK_FOR_INSN(INSN)  VARRAY_BB (basic_block_for_insn, INSN_UID (INSN))
 220 #define BLOCK_NUM(INSN)       (BLOCK_FOR_INSN (INSN)->index + 0)
 221
 222 extern void compute_bb_for_insn         PARAMS ((int));
 223 extern void set_block_for_insn          PARAMS ((rtx, basic_block));
 224 extern void set_block_num               PARAMS ((rtx, int));
 225
 226 extern void free_basic_block_vars       PARAMS ((int));
 227
 228 extern basic_block split_edge           PARAMS ((edge));
 229 extern void insert_insn_on_edge         PARAMS ((rtx, edge));
 230 extern void commit_edge_insertions      PARAMS ((void));
 231 extern void remove_fake_edges           PARAMS ((void));
 232 extern void add_noreturn_fake_exit_edges        PARAMS ((void));
 233 extern rtx flow_delete_insn             PARAMS ((rtx));
 234 extern void flow_delete_insn_chain      PARAMS ((rtx, rtx));
 235 extern void make_edge                   PARAMS ((sbitmap *, basic_block,
 236                                                  basic_block, int));
 237 extern void remove_edge                 PARAMS ((edge));
 238 extern void redirect_edge_succ          PARAMS ((edge, basic_block));
 239 extern void redirect_edge_pred          PARAMS ((edge, basic_block));
 240 extern void create_basic_block          PARAMS ((int, rtx, rtx, rtx));
 241 extern int flow_delete_block            PARAMS ((basic_block));
 242 extern void merge_blocks_nomove         PARAMS ((basic_block, basic_block));
 243 extern void tidy_fallthru_edge          PARAMS ((edge, basic_block,
 244                                                  basic_block));
 245
 246 /* Structure to hold information for each natural loop.  */
 247 struct loop
 248 {
 249   /* Index into loops array.  */
 250   int num;
 251
 252   /* Basic block of loop header.  */
 253   basic_block header;
 254
 255   /* Basic block of loop latch.  */
 256   basic_block latch;
 257
 258   /* Basic block of loop pre-header or NULL if it does not exist.  */
 259   basic_block pre_header;
 260
 261   /* The first block in the loop.  This is not necessarily the same as
 262      the loop header.  */
 263   basic_block first;
 264
 265   /* The last block in the loop.  This is not necessarily the same as
 266      the loop latch.  */
 267   basic_block last;
 268
 269   /* Bitmap of blocks contained within the loop.  */
 270   sbitmap nodes;
 271
 272   /* Number of blocks contained within the loop.  */
 273   int num_nodes;
 274
 275   /* Array of edges that exit the loop.  */
 276   edge *exits;
 277
 278   /* Number of edges that exit the loop.  */
 279   int num_exits;
 280
 281   /* The loop nesting depth.  */
 282   int depth;
 283
 284   /* The height of the loop (enclosed loop levels) within the loop
 285      hierarchy tree.  */
 286   int level;
 287
 288   /* The outer (parent) loop or NULL if outermost loop.  */
 289   struct loop *outer;
 290
 291   /* The first inner (child) loop or NULL if innermost loop.  */
 292   struct loop *inner;
 293
 294   /* Link to the next (sibling) loop.  */
 295   struct loop *next;
 296
 297   /* Non-zero if the loop shares a header with another loop.  */
 298   int shared;
 299
 300   /* Non-zero if the loop is invalid (e.g., contains setjmp.).  */
 301   int invalid;
 302
 303   /* Auxiliary info specific to a pass.  */
 304   void *aux;
 305
 306   /* The following are currently used by loop.c but they are likely to
 307      disappear as loop.c is converted to use the CFG.  */
 308
 309   /* Non-zero if the loop has a NOTE_INSN_LOOP_VTOP.  */
 310   rtx vtop;
 311
 312   /* Non-zero if the loop has a NOTE_INSN_LOOP_CONT.
 313      A continue statement will generate a branch to NEXT_INSN (cont).  */
 314   rtx cont;
 315
 316   /* The dominator of cont.  */
 317   rtx cont_dominator;
 318
 319   /* The NOTE_INSN_LOOP_BEG.  */
 320   rtx start;
 321
 322   /* The NOTE_INSN_LOOP_END.  */
 323   rtx end;
 324
 325   /* For a rotated loop that is entered near the bottom,
 326      this is the label at the top.  Otherwise it is zero.  */
 327   rtx top;
 328
 329   /* Place in the loop where control enters.  */
 330   rtx scan_start;
 331
 332   /* List of all LABEL_REFs which refer to code labels outside the
 333      loop.  Used by routines that need to know all loop exits, such as
 334      final_biv_value and final_giv_value.
 335
 336      This does not include loop exits due to return instructions.
 337      This is because all bivs and givs are pseudos, and hence must be
 338      dead after a return, so the presense of a return does not affect
 339      any of the optimizations that use this info.  It is simpler to
 340      just not include return instructions on this list.  */
 341   rtx exit_labels;
 342
 343   /* The number of LABEL_REFs on exit_labels for this loop and all
 344      loops nested inside it.  */
 345   int exit_count;
 346 };
 347
 348
 349 /* Structure to hold CFG information about natural loops within a function.  */
 350 struct loops
 351 {
 352   /* Number of natural loops in the function.  */
 353   int num;
 354
 355   /* Maxium nested loop level in the function.  */
 356   int levels;
 357
 358   /* Array of natural loop descriptors (scanning this array in reverse order
 359      will find the inner loops before their enclosing outer loops).  */
 360   struct loop *array;
 361
 362   /* Pointer to root of loop heirachy tree.  */
 363   struct loop *tree;
 364
 365   /* Information derived from the CFG.  */
 366   struct cfg
 367   {
 368     /* The bitmap vector of dominators or NULL if not computed.  */
 369     sbitmap *dom;
 370
 371     /* The ordering of the basic blocks in a depth first search.  */
 372     int *dfs_order;
 373
 374     /* The reverse completion ordering of the basic blocks found in a
 375        depth first search.  */
 376     int *rc_order;
 377   } cfg;
 378
 379   /* Headers shared by multiple loops that should be merged.  */
 380   sbitmap shared_headers;
 381 };
 382
 383 extern int flow_loops_find PARAMS ((struct loops *));
 384 extern void flow_loops_free PARAMS ((struct loops *));
 385 extern void flow_loops_dump PARAMS ((const struct loops *, FILE *, int));
 386
 387
 388 /* This structure maintains an edge list vector.  */
 389 struct edge_list
 390 {
 391   int num_blocks;
 392   int num_edges;
 393   edge *index_to_edge;
 394 };
 395
 396 /* This is the value which indicates no edge is present.  */
 397 #define EDGE_INDEX_NO_EDGE      -1
 398
 399 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 400    if there is no edge between the 2 basic blocks.  */
 401 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 402
 403 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 404    block which is either the pred or succ end of the indexed edge.  */
 405 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 406 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 407
 408 /* INDEX_EDGE returns a pointer to the edge.  */
 409 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 410
 411 /* Number of edges in the compressed edge list.  */
 412 #define NUM_EDGES(el)                   ((el)->num_edges)
 413
 414 struct edge_list * create_edge_list     PARAMS ((void));
 415 void free_edge_list                     PARAMS ((struct edge_list *));
 416 void print_edge_list                    PARAMS ((FILE *, struct edge_list *));
 417 void verify_edge_list                   PARAMS ((FILE *, struct edge_list *));
 418 int find_edge_index                     PARAMS ((struct edge_list *,
 419                                                  basic_block, basic_block));
 420
 421 extern void compute_flow_dominators     PARAMS ((sbitmap *, sbitmap *));
 422 extern void compute_immediate_dominators        PARAMS ((int *, sbitmap *));
 423 extern void compute_immediate_postdominators    PARAMS ((int *, sbitmap *));
 424
 425
 426 enum update_life_extent
 427 {
 428   UPDATE_LIFE_LOCAL = 0,
 429   UPDATE_LIFE_GLOBAL = 1,
 430   UPDATE_LIFE_GLOBAL_RM_NOTES = 2
 431 };
 432
 433 /* Flags for life_analysis and update_life_info.  */
 434
 435 #define PROP_DEATH_NOTES        1       /* Create DEAD and UNUSED notes.  */
 436 #define PROP_LOG_LINKS          2       /* Create LOG_LINKS.  */
 437 #define PROP_REG_INFO           4       /* Update regs_ever_live et al.  */
 438 #define PROP_KILL_DEAD_CODE     8       /* Remove dead code.  */
 439 #define PROP_SCAN_DEAD_CODE     16      /* Scan for dead code.  */
 440 #define PROP_AUTOINC            32      /* Create autoinc mem references.  */
 441 #define PROP_FINAL              63      /* All of the above.  */
 442
 443 extern void life_analysis       PARAMS ((rtx, FILE *, int));
 444 extern void update_life_info    PARAMS ((sbitmap, enum update_life_extent,
 445                                          int));
 446 extern int count_or_remove_death_notes  PARAMS ((sbitmap, int));
 447 extern void propagate_block     PARAMS ((basic_block, regset, regset, int));
 448
 449 struct propagate_block_info;
 450 extern rtx propagate_one_insn   PARAMS ((struct propagate_block_info *, rtx));
 451 extern struct propagate_block_info *init_propagate_block_info
 452   PARAMS ((basic_block, regset, regset, int));
 453 extern void free_propagate_block_info PARAMS ((struct propagate_block_info *));
 454
 455 /* In lcm.c */
 456 extern struct edge_list *pre_edge_lcm   PARAMS ((FILE *, int, sbitmap *,
 457                                                  sbitmap *, sbitmap *,
 458                                                  sbitmap *, sbitmap **,
 459                                                  sbitmap **));
 460 extern struct edge_list *pre_edge_rev_lcm PARAMS ((FILE *, int, sbitmap *,
 461                                                    sbitmap *, sbitmap *,
 462                                                    sbitmap *, sbitmap **,
 463                                                    sbitmap **));
 464 extern void compute_available           PARAMS ((sbitmap *, sbitmap *,
 465                                                  sbitmap *, sbitmap *));
 466 extern int optimize_mode_switching      PARAMS ((FILE *));
 467
 468 /* In emit-rtl.c.  */
 469 extern rtx emit_block_insn_after        PARAMS ((rtx, rtx, basic_block));
 470 extern rtx emit_block_insn_before       PARAMS ((rtx, rtx, basic_block));
 471
 472 /* In predict.c */
 473 extern void estimate_probability        PARAMS ((struct loops *));
 474 extern void expected_value_to_br_prob   PARAMS ((void));
 475
 476 /* In flow.c */
 477 extern void reorder_basic_blocks        PARAMS ((void));
 478 extern void dump_bb                     PARAMS ((basic_block, FILE *));
 479 extern void debug_bb                    PARAMS ((basic_block));
 480 extern void debug_bb_n                  PARAMS ((int));
 481 extern void dump_regset                 PARAMS ((regset, FILE *));
 482 extern void debug_regset                PARAMS ((regset));
 483
 484 /* This function is always defined so it can be called from the
 485    debugger, and it is declared extern so we don't get warnings about
 486    it being unused. */
 487 extern void verify_flow_info            PARAMS ((void));
 488 extern int flow_loop_outside_edge_p     PARAMS ((const struct loop *, edge));
 489
 490 typedef struct conflict_graph_def *conflict_graph;
 491
 492 /* Callback function when enumerating conflicts.  The arguments are
 493    the smaller and larger regno in the conflict.  Returns zero if
 494    enumeration is to continue, non-zero to halt enumeration.  */
 495 typedef int (*conflict_graph_enum_fn) PARAMS ((int, int, void *));
 496
 497
 498 /* Prototypes of operations on conflict graphs.  */
 499
 500 extern conflict_graph conflict_graph_new
 501                                         PARAMS ((int));
 502 extern void conflict_graph_delete       PARAMS ((conflict_graph));
 503 extern int conflict_graph_add           PARAMS ((conflict_graph,
 504                                                  int, int));
 505 extern int conflict_graph_conflict_p    PARAMS ((conflict_graph,
 506                                                  int, int));
 507 extern void conflict_graph_enum         PARAMS ((conflict_graph, int,
 508                                                  conflict_graph_enum_fn,
 509                                                  void *));
 510 extern void conflict_graph_merge_regs   PARAMS ((conflict_graph, int,
 511                                                  int));
 512 extern void conflict_graph_print        PARAMS ((conflict_graph, FILE*));
 513 extern conflict_graph conflict_graph_compute
 514                                         PARAMS ((regset,
 515                                                  partition));
 516
 517 /* In ssa.c */
 518 extern void convert_to_ssa              PARAMS ((void));
 519 extern void convert_from_ssa            PARAMS ((void));
 520 typedef int (*successor_phi_fn)         PARAMS ((rtx, int, int, void *));
 521 extern int for_each_successor_phi       PARAMS ((basic_block bb,
 522                                                  successor_phi_fn,
 523                                                  void *));
 524 extern int in_ssa_form;
 525
 526 #endif /* _BASIC_BLOCK_H */