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 blocks need not start with a label nor end with a jump insn.
 145    For example, a previous basic block may just "conditionally fall"
 146    into the succeeding basic block, and the last basic block need not
 147    end with a jump insn.  Block 0 is a descendant of the entry block.
 148
 149    A basic block beginning with two labels cannot have notes between
 150    the labels.
 151
 152    Data for jump tables are stored in jump_insns that occur in no
 153    basic block even though these insns can follow or precede insns in
 154    basic blocks.  */
 155
 156 /* Basic block information indexed by block number.  */
 157 typedef struct basic_block_def {
 158   /* The first and last insns of the block.  */
 159   rtx head, end;
 160
 161   /* The edges into and out of the block.  */
 162   edge pred, succ;
 163
 164   /* Liveness info.  Note that in SSA form, global_live_at_start does
 165      not reflect the use of regs in phi functions, since the liveness
 166      of these regs may depend on which edge was taken into the block.  */
 167   regset local_set;
 168   regset global_live_at_start;
 169   regset global_live_at_end;
 170
 171   /* Auxiliary info specific to a pass.  */
 172   void *aux;
 173
 174   /* The index of this block.  */
 175   int index;
 176   /* The loop depth of this block plus one.  */
 177   int loop_depth;
 178
 179   /* The active eh region before head and after end.  */
 180   int eh_beg, eh_end;
 181
 182   int count;            /* Expected number of executions: calculated in
 183                            profile.c */
 184 } *basic_block;
 185
 186 /* Number of basic blocks in the current function.  */
 187
 188 extern int n_basic_blocks;
 189
 190 /* Number of edges in the current function.  */
 191
 192 extern int n_edges;
 193
 194 /* Index by basic block number, get basic block struct info.  */
 195
 196 extern varray_type basic_block_info;
 197
 198 #define BASIC_BLOCK(N)  (VARRAY_BB (basic_block_info, (N)))
 199
 200 /* What registers are live at the setjmp call.  */
 201
 202 extern regset regs_live_at_setjmp;
 203
 204 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 205    If the value is REG_BLOCK_GLOBAL (-2),
 206    it means (REG n) is used in more than one basic block.
 207    REG_BLOCK_UNKNOWN (-1) means it hasn't been seen yet so we don't know.
 208    This information remains valid for the rest of the compilation
 209    of the current function; it is used to control register allocation.  */
 210
 211 #define REG_BLOCK_UNKNOWN -1
 212 #define REG_BLOCK_GLOBAL -2
 213
 214 #define REG_BASIC_BLOCK(N) (VARRAY_REG (reg_n_info, N)->basic_block)
 215 \f
 216 /* Stuff for recording basic block info.  */
 217
 218 #define BLOCK_HEAD(B)      (BASIC_BLOCK (B)->head)
 219 #define BLOCK_END(B)       (BASIC_BLOCK (B)->end)
 220
 221 /* Special block numbers [markers] for entry and exit.  */
 222 #define ENTRY_BLOCK (-1)
 223 #define EXIT_BLOCK (-2)
 224
 225 /* Special block number not valid for any block. */
 226 #define INVALID_BLOCK (-3)
 227
 228 /* Similarly, block pointers for the edge list.  */
 229 extern struct basic_block_def entry_exit_blocks[2];
 230 #define ENTRY_BLOCK_PTR (&entry_exit_blocks[0])
 231 #define EXIT_BLOCK_PTR  (&entry_exit_blocks[1])
 232
 233 extern varray_type basic_block_for_insn;
 234 #define BLOCK_FOR_INSN(INSN)  VARRAY_BB (basic_block_for_insn, INSN_UID (INSN))
 235 #define BLOCK_NUM(INSN)       (BLOCK_FOR_INSN (INSN)->index + 0)
 236
 237 extern void compute_bb_for_insn         PARAMS ((int));
 238 extern void set_block_for_insn          PARAMS ((rtx, basic_block));
 239 extern void set_block_num               PARAMS ((rtx, int));
 240
 241 extern void free_basic_block_vars       PARAMS ((int));
 242
 243 extern basic_block split_edge           PARAMS ((edge));
 244 extern void insert_insn_on_edge         PARAMS ((rtx, edge));
 245 extern void commit_edge_insertions      PARAMS ((void));
 246 extern void remove_fake_edges           PARAMS ((void));
 247 extern void add_noreturn_fake_exit_edges        PARAMS ((void));
 248 extern void connect_infinite_loops_to_exit      PARAMS ((void));
 249 extern rtx flow_delete_insn             PARAMS ((rtx));
 250 extern void flow_delete_insn_chain      PARAMS ((rtx, rtx));
 251 extern void make_edge                   PARAMS ((sbitmap *, basic_block,
 252                                                  basic_block, int));
 253 extern void remove_edge                 PARAMS ((edge));
 254 extern void redirect_edge_succ          PARAMS ((edge, basic_block));
 255 extern void redirect_edge_pred          PARAMS ((edge, basic_block));
 256 extern void create_basic_block          PARAMS ((int, rtx, rtx, rtx));
 257 extern int flow_delete_block            PARAMS ((basic_block));
 258 extern void merge_blocks_nomove         PARAMS ((basic_block, basic_block));
 259 extern void tidy_fallthru_edge          PARAMS ((edge, basic_block,
 260                                                  basic_block));
 261
 262 /* Structure to hold information for each natural loop.  */
 263 struct loop
 264 {
 265   /* Index into loops array.  */
 266   int num;
 267
 268   /* Basic block of loop header.  */
 269   basic_block header;
 270
 271   /* Basic block of loop latch.  */
 272   basic_block latch;
 273
 274   /* Basic block of loop pre-header or NULL if it does not exist.  */
 275   basic_block pre_header;
 276
 277   /* The first block in the loop.  This is not necessarily the same as
 278      the loop header.  */
 279   basic_block first;
 280
 281   /* The last block in the loop.  This is not necessarily the same as
 282      the loop latch.  */
 283   basic_block last;
 284
 285   /* Bitmap of blocks contained within the loop.  */
 286   sbitmap nodes;
 287
 288   /* Number of blocks contained within the loop.  */
 289   int num_nodes;
 290
 291   /* Array of edges that exit the loop.  */
 292   edge *exits;
 293
 294   /* Number of edges that exit the loop.  */
 295   int num_exits;
 296
 297   /* The loop nesting depth.  */
 298   int depth;
 299
 300   /* The height of the loop (enclosed loop levels) within the loop
 301      hierarchy tree.  */
 302   int level;
 303
 304   /* The outer (parent) loop or NULL if outermost loop.  */
 305   struct loop *outer;
 306
 307   /* The first inner (child) loop or NULL if innermost loop.  */
 308   struct loop *inner;
 309
 310   /* Link to the next (sibling) loop.  */
 311   struct loop *next;
 312
 313   /* Non-zero if the loop shares a header with another loop.  */
 314   int shared;
 315
 316   /* Non-zero if the loop is invalid (e.g., contains setjmp.).  */
 317   int invalid;
 318
 319   /* Auxiliary info specific to a pass.  */
 320   void *aux;
 321
 322   /* The following are currently used by loop.c but they are likely to
 323      disappear as loop.c is converted to use the CFG.  */
 324
 325   /* Non-zero if the loop has a NOTE_INSN_LOOP_VTOP.  */
 326   rtx vtop;
 327
 328   /* Non-zero if the loop has a NOTE_INSN_LOOP_CONT.
 329      A continue statement will generate a branch to NEXT_INSN (cont).  */
 330   rtx cont;
 331
 332   /* The dominator of cont.  */
 333   rtx cont_dominator;
 334
 335   /* The NOTE_INSN_LOOP_BEG.  */
 336   rtx start;
 337
 338   /* The NOTE_INSN_LOOP_END.  */
 339   rtx end;
 340
 341   /* For a rotated loop that is entered near the bottom,
 342      this is the label at the top.  Otherwise it is zero.  */
 343   rtx top;
 344
 345   /* Place in the loop where control enters.  */
 346   rtx scan_start;
 347
 348   /* List of all LABEL_REFs which refer to code labels outside the
 349      loop.  Used by routines that need to know all loop exits, such as
 350      final_biv_value and final_giv_value.
 351
 352      This does not include loop exits due to return instructions.
 353      This is because all bivs and givs are pseudos, and hence must be
 354      dead after a return, so the presense of a return does not affect
 355      any of the optimizations that use this info.  It is simpler to
 356      just not include return instructions on this list.  */
 357   rtx exit_labels;
 358
 359   /* The number of LABEL_REFs on exit_labels for this loop and all
 360      loops nested inside it.  */
 361   int exit_count;
 362 };
 363
 364
 365 /* Structure to hold CFG information about natural loops within a function.  */
 366 struct loops
 367 {
 368   /* Number of natural loops in the function.  */
 369   int num;
 370
 371   /* Maxium nested loop level in the function.  */
 372   int levels;
 373
 374   /* Array of natural loop descriptors (scanning this array in reverse order
 375      will find the inner loops before their enclosing outer loops).  */
 376   struct loop *array;
 377
 378   /* Pointer to root of loop heirachy tree.  */
 379   struct loop *tree;
 380
 381   /* Information derived from the CFG.  */
 382   struct cfg
 383   {
 384     /* The bitmap vector of dominators or NULL if not computed.  */
 385     sbitmap *dom;
 386
 387     /* The ordering of the basic blocks in a depth first search.  */
 388     int *dfs_order;
 389
 390     /* The reverse completion ordering of the basic blocks found in a
 391        depth first search.  */
 392     int *rc_order;
 393   } cfg;
 394
 395   /* Headers shared by multiple loops that should be merged.  */
 396   sbitmap shared_headers;
 397 };
 398
 399 extern int flow_loops_find PARAMS ((struct loops *));
 400 extern void flow_loops_free PARAMS ((struct loops *));
 401 extern void flow_loops_dump PARAMS ((const struct loops *, FILE *, int));
 402
 403
 404 /* This structure maintains an edge list vector.  */
 405 struct edge_list
 406 {
 407   int num_blocks;
 408   int num_edges;
 409   edge *index_to_edge;
 410 };
 411
 412 /* This is the value which indicates no edge is present.  */
 413 #define EDGE_INDEX_NO_EDGE      -1
 414
 415 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 416    if there is no edge between the 2 basic blocks.  */
 417 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 418
 419 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 420    block which is either the pred or succ end of the indexed edge.  */
 421 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 422 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 423
 424 /* INDEX_EDGE returns a pointer to the edge.  */
 425 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 426
 427 /* Number of edges in the compressed edge list.  */
 428 #define NUM_EDGES(el)                   ((el)->num_edges)
 429
 430 struct edge_list * create_edge_list     PARAMS ((void));
 431 void free_edge_list                     PARAMS ((struct edge_list *));
 432 void print_edge_list                    PARAMS ((FILE *, struct edge_list *));
 433 void verify_edge_list                   PARAMS ((FILE *, struct edge_list *));
 434 int find_edge_index                     PARAMS ((struct edge_list *,
 435                                                  basic_block, basic_block));
 436
 437 extern void compute_flow_dominators     PARAMS ((sbitmap *, sbitmap *));
 438 extern void compute_immediate_dominators        PARAMS ((int *, sbitmap *));
 439 extern void compute_immediate_postdominators    PARAMS ((int *, sbitmap *));
 440
 441
 442 enum update_life_extent
 443 {
 444   UPDATE_LIFE_LOCAL = 0,
 445   UPDATE_LIFE_GLOBAL = 1,
 446   UPDATE_LIFE_GLOBAL_RM_NOTES = 2
 447 };
 448
 449 /* Flags for life_analysis and update_life_info.  */
 450
 451 #define PROP_DEATH_NOTES        1       /* Create DEAD and UNUSED notes.  */
 452 #define PROP_LOG_LINKS          2       /* Create LOG_LINKS.  */
 453 #define PROP_REG_INFO           4       /* Update regs_ever_live et al.  */
 454 #define PROP_KILL_DEAD_CODE     8       /* Remove dead code.  */
 455 #define PROP_SCAN_DEAD_CODE     16      /* Scan for dead code.  */
 456 #define PROP_AUTOINC            32      /* Create autoinc mem references.  */
 457 #define PROP_FINAL              63      /* All of the above.  */
 458
 459 extern void life_analysis       PARAMS ((rtx, FILE *, int));
 460 extern void update_life_info    PARAMS ((sbitmap, enum update_life_extent,
 461                                          int));
 462 extern int count_or_remove_death_notes  PARAMS ((sbitmap, int));
 463 extern void propagate_block     PARAMS ((basic_block, regset, regset, int));
 464
 465 struct propagate_block_info;
 466 extern rtx propagate_one_insn   PARAMS ((struct propagate_block_info *, rtx));
 467 extern struct propagate_block_info *init_propagate_block_info
 468   PARAMS ((basic_block, regset, regset, int));
 469 extern void free_propagate_block_info PARAMS ((struct propagate_block_info *));
 470
 471 /* In lcm.c */
 472 extern struct edge_list *pre_edge_lcm   PARAMS ((FILE *, int, sbitmap *,
 473                                                  sbitmap *, sbitmap *,
 474                                                  sbitmap *, sbitmap **,
 475                                                  sbitmap **));
 476 extern struct edge_list *pre_edge_rev_lcm PARAMS ((FILE *, int, sbitmap *,
 477                                                    sbitmap *, sbitmap *,
 478                                                    sbitmap *, sbitmap **,
 479                                                    sbitmap **));
 480 extern void compute_available           PARAMS ((sbitmap *, sbitmap *,
 481                                                  sbitmap *, sbitmap *));
 482 extern int optimize_mode_switching      PARAMS ((FILE *));
 483
 484 /* In emit-rtl.c.  */
 485 extern rtx emit_block_insn_after        PARAMS ((rtx, rtx, basic_block));
 486 extern rtx emit_block_insn_before       PARAMS ((rtx, rtx, basic_block));
 487
 488 /* In predict.c */
 489 extern void estimate_probability        PARAMS ((struct loops *));
 490 extern void expected_value_to_br_prob   PARAMS ((void));
 491
 492 /* In flow.c */
 493 extern void reorder_basic_blocks        PARAMS ((void));
 494 extern void dump_bb                     PARAMS ((basic_block, FILE *));
 495 extern void debug_bb                    PARAMS ((basic_block));
 496 extern void debug_bb_n                  PARAMS ((int));
 497 extern void dump_regset                 PARAMS ((regset, FILE *));
 498 extern void debug_regset                PARAMS ((regset));
 499
 500 /* This function is always defined so it can be called from the
 501    debugger, and it is declared extern so we don't get warnings about
 502    it being unused. */
 503 extern void verify_flow_info            PARAMS ((void));
 504 extern int flow_loop_outside_edge_p     PARAMS ((const struct loop *, edge));
 505
 506 typedef struct conflict_graph_def *conflict_graph;
 507
 508 /* Callback function when enumerating conflicts.  The arguments are
 509    the smaller and larger regno in the conflict.  Returns zero if
 510    enumeration is to continue, non-zero to halt enumeration.  */
 511 typedef int (*conflict_graph_enum_fn) PARAMS ((int, int, void *));
 512
 513
 514 /* Prototypes of operations on conflict graphs.  */
 515
 516 extern conflict_graph conflict_graph_new
 517                                         PARAMS ((int));
 518 extern void conflict_graph_delete       PARAMS ((conflict_graph));
 519 extern int conflict_graph_add           PARAMS ((conflict_graph,
 520                                                  int, int));
 521 extern int conflict_graph_conflict_p    PARAMS ((conflict_graph,
 522                                                  int, int));
 523 extern void conflict_graph_enum         PARAMS ((conflict_graph, int,
 524                                                  conflict_graph_enum_fn,
 525                                                  void *));
 526 extern void conflict_graph_merge_regs   PARAMS ((conflict_graph, int,
 527                                                  int));
 528 extern void conflict_graph_print        PARAMS ((conflict_graph, FILE*));
 529 extern conflict_graph conflict_graph_compute
 530                                         PARAMS ((regset,
 531                                                  partition));
 532
 533 #endif /* _BASIC_BLOCK_H */