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