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 #define REG_SET_TO_HARD_REG_SET(TO, FROM)                               \
  74 do {                                                                    \
  75   int i_;                                                               \
  76   CLEAR_HARD_REG_SET (TO);                                              \
  77   for (i_ = 0; i_ < FIRST_PSEUDO_REGISTER; i_++)                        \
  78     if (REGNO_REG_SET_P (FROM, i_))                                     \
  79       SET_HARD_REG_BIT (TO, i_);                                        \
  80 } while (0)
  81
  82 /* Loop over all registers in REGSET, starting with MIN, setting REGNUM to the
  83    register number and executing CODE for all registers that are set. */
  84 #define EXECUTE_IF_SET_IN_REG_SET(REGSET, MIN, REGNUM, CODE)            \
  85   EXECUTE_IF_SET_IN_BITMAP (REGSET, MIN, REGNUM, CODE)
  86
  87 /* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
  88    REGNUM to the register number and executing CODE for all registers that are
  89    set in the first regset and not set in the second. */
  90 #define EXECUTE_IF_AND_COMPL_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, CODE) \
  91   EXECUTE_IF_AND_COMPL_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, CODE)
  92
  93 /* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
  94    REGNUM to the register number and executing CODE for all registers that are
  95    set in both regsets. */
  96 #define EXECUTE_IF_AND_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, CODE) \
  97   EXECUTE_IF_AND_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, CODE)
  98
  99 /* Allocate a register set with oballoc.  */
 100 #define OBSTACK_ALLOC_REG_SET(OBSTACK) BITMAP_OBSTACK_ALLOC (OBSTACK)
 101
 102 /* Initialize a register set.  Returns the new register set.  */
 103 #define INITIALIZE_REG_SET(HEAD) bitmap_initialize (&HEAD)
 104
 105 /* Do any cleanup needed on a regset when it is no longer used.  */
 106 #define FREE_REG_SET(REGSET) BITMAP_FREE(REGSET)
 107
 108 /* Do any one-time initializations needed for regsets.  */
 109 #define INIT_ONCE_REG_SET() BITMAP_INIT_ONCE ()
 110
 111 /* Grow any tables needed when the number of registers is calculated
 112    or extended.  For the linked list allocation, nothing needs to
 113    be done, other than zero the statistics on the first allocation.  */
 114 #define MAX_REGNO_REG_SET(NUM_REGS, NEW_P, RENUMBER_P)
 115
 116 /* Control flow edge information.  */
 117 typedef struct edge_def {
 118   /* Links through the predecessor and successor lists.  */
 119   struct edge_def *pred_next, *succ_next;
 120
 121   /* The two blocks at the ends of the edge.  */
 122   struct basic_block_def *src, *dest;
 123
 124   /* Instructions queued on the edge.  */
 125   rtx insns;
 126
 127   /* Auxiliary info specific to a pass.  */
 128   void *aux;
 129
 130   int flags;                    /* see EDGE_* below  */
 131   int probability;              /* biased by REG_BR_PROB_BASE */
 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 } *basic_block;
 168
 169 /* Number of basic blocks in the current function.  */
 170
 171 extern int n_basic_blocks;
 172
 173 /* Number of edges in the current function.  */
 174
 175 extern int n_edges;
 176
 177 /* Index by basic block number, get basic block struct info.  */
 178
 179 extern varray_type basic_block_info;
 180
 181 #define BASIC_BLOCK(N)  (VARRAY_BB (basic_block_info, (N)))
 182
 183 /* What registers are live at the setjmp call.  */
 184
 185 extern regset regs_live_at_setjmp;
 186
 187 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 188    If the value is REG_BLOCK_GLOBAL (-2),
 189    it means (REG n) is used in more than one basic block.
 190    REG_BLOCK_UNKNOWN (-1) means it hasn't been seen yet so we don't know.
 191    This information remains valid for the rest of the compilation
 192    of the current function; it is used to control register allocation.  */
 193
 194 #define REG_BLOCK_UNKNOWN -1
 195 #define REG_BLOCK_GLOBAL -2
 196
 197 #define REG_BASIC_BLOCK(N) (VARRAY_REG (reg_n_info, N)->basic_block)
 198 \f
 199 /* Stuff for recording basic block info.  */
 200
 201 #define BLOCK_HEAD(B)      (BASIC_BLOCK (B)->head)
 202 #define BLOCK_END(B)       (BASIC_BLOCK (B)->end)
 203
 204 /* Special block numbers [markers] for entry and exit.  */
 205 #define ENTRY_BLOCK (-1)
 206 #define EXIT_BLOCK (-2)
 207
 208 /* Similarly, block pointers for the edge list.  */
 209 extern struct basic_block_def entry_exit_blocks[2];
 210 #define ENTRY_BLOCK_PTR (&entry_exit_blocks[0])
 211 #define EXIT_BLOCK_PTR  (&entry_exit_blocks[1])
 212
 213 extern varray_type basic_block_for_insn;
 214 #define BLOCK_FOR_INSN(INSN)  VARRAY_BB (basic_block_for_insn, INSN_UID (INSN))
 215 #define BLOCK_NUM(INSN)       (BLOCK_FOR_INSN (INSN)->index + 0)
 216
 217 extern void compute_bb_for_insn         PARAMS ((int));
 218 extern void set_block_for_insn          PARAMS ((rtx, basic_block));
 219 extern void set_block_num               PARAMS ((rtx, int));
 220
 221 extern void free_basic_block_vars       PARAMS ((int));
 222
 223 extern basic_block split_edge           PARAMS ((edge));
 224 extern void insert_insn_on_edge         PARAMS ((rtx, edge));
 225 extern void commit_edge_insertions      PARAMS ((void));
 226 extern void remove_fake_edges           PARAMS ((void));
 227 extern void add_noreturn_fake_exit_edges        PARAMS ((void));
 228 extern rtx flow_delete_insn             PARAMS ((rtx));
 229 extern void flow_delete_insn_chain      PARAMS ((rtx, rtx));
 230 extern void make_edge                   PARAMS ((sbitmap *, basic_block,
 231                                                  basic_block, int));
 232 extern void remove_edge                 PARAMS ((edge));
 233 extern void create_basic_block          PARAMS ((int, rtx, rtx, rtx));
 234 extern int flow_delete_block            PARAMS ((basic_block));
 235 extern void merge_blocks_nomove         PARAMS ((basic_block, basic_block));
 236 extern void tidy_fallthru_edge          PARAMS ((edge, basic_block,
 237                                                  basic_block));
 238
 239 /* Structure to hold information for each natural loop.  */
 240 struct loop
 241 {
 242   int num;
 243
 244   /* Basic block of loop header.  */
 245   basic_block header;
 246
 247   /* Basic block of loop latch.  */
 248   basic_block latch;
 249
 250   /* Basic block of loop pre-header or NULL if it does not exist.  */
 251   basic_block pre_header;
 252
 253   /* The first block in the loop.  This is not necessarily the same as
 254      the loop header.  */
 255   basic_block first;
 256
 257   /* The last block in the loop.  This is not necessarily the same as
 258      the loop latch.  */
 259   basic_block last;
 260
 261   /* Bitmap of blocks contained within the loop.  */
 262   sbitmap nodes;
 263
 264   /* Number of blocks contained within the loop.  */
 265   int num_nodes;
 266
 267   /* Array of edges that exit the loop.  */
 268   edge *exits;
 269
 270   /* Number of edges that exit the loop.  */
 271   int num_exits;
 272
 273   /* The loop nesting depth.  */
 274   int depth;
 275
 276   /* The height of the loop (enclosed loop levels) within the loop
 277      hierarchy tree.  */
 278   int level;
 279
 280   /* The outer (parent) loop or NULL if outermost loop.  */
 281   struct loop *outer;
 282
 283   /* The first inner (child) loop or NULL if innermost loop.  */
 284   struct loop *inner;
 285
 286   /* Link to the next (sibling) loop.  */
 287   struct loop *next;
 288
 289   /* Non-zero if the loop shares a header with another loop.  */
 290   int shared;
 291
 292   /* Non-zero if the loop is invalid (e.g., contains setjmp.).  */
 293   int invalid;
 294
 295   /* Auxiliary info specific to a pass.  */
 296   void *aux;
 297
 298   /* The following are currently used by loop.c but they are likely to
 299      disappear as loop.c is converted to use the CFG.  */
 300
 301   /* Non-zero if the loop has a NOTE_INSN_LOOP_VTOP.  */
 302   rtx vtop;
 303
 304   /* Non-zero if the loop has a NOTE_INSN_LOOP_CONT.
 305      A continue statement will generate a branch to NEXT_INSN (cont).  */
 306   rtx cont;
 307
 308   /* The dominator of cont.  */
 309   rtx cont_dominator;
 310
 311   /* The NOTE_INSN_LOOP_BEG.  */
 312   rtx start;
 313
 314   /* The NOTE_INSN_LOOP_END.  */
 315   rtx end;
 316
 317   /* For a rotated loop that is entered near the bottom,
 318      this is the label at the top.  Otherwise it is zero.  */
 319   rtx top;
 320
 321   /* Place in the loop where control enters.  */
 322   rtx scan_start;
 323
 324   /* List of all LABEL_REFs which refer to code labels outside the
 325      loop.  Used by routines that need to know all loop exits, such as
 326      final_biv_value and final_giv_value.
 327
 328      This does not include loop exits due to return instructions.
 329      This is because all bivs and givs are pseudos, and hence must be
 330      dead after a return, so the presense of a return does not affect
 331      any of the optimizations that use this info.  It is simpler to
 332      just not include return instructions on this list.  */
 333   rtx exit_labels;
 334
 335   /* The number of LABEL_REFs on exit_labels for this loop and all
 336      loops nested inside it.  */
 337   int exit_count;
 338 };
 339
 340
 341 /* Structure to hold CFG information about natural loops within a function.  */
 342 struct loops
 343 {
 344   /* Number of natural loops in the function.  */
 345   int num;
 346
 347   /* Maxium nested loop level in the function.  */
 348   int levels;
 349
 350   /* Array of natural loop descriptors (scanning this array in reverse order
 351      will find the inner loops before their enclosing outer loops).  */
 352   struct loop *array;
 353
 354   /* Pointer to root of loop heirachy tree.  */
 355   struct loop *tree;
 356
 357   /* Information derived from the CFG.  */
 358   struct cfg
 359   {
 360     /* The bitmap vector of dominators or NULL if not computed.  */
 361     sbitmap *dom;
 362
 363     /* The ordering of the basic blocks in a depth first search.  */
 364     int *dfs_order;
 365   } cfg;
 366
 367   /* Headers shared by multiple loops that should be merged.  */
 368   sbitmap shared_headers;
 369 };
 370
 371 extern int flow_loops_find PARAMS ((struct loops *));
 372 extern void flow_loops_free PARAMS ((struct loops *));
 373 extern void flow_loops_dump PARAMS ((const struct loops *, FILE *, int));
 374
 375
 376 /* This structure maintains an edge list vector.  */
 377 struct edge_list
 378 {
 379   int num_blocks;
 380   int num_edges;
 381   edge *index_to_edge;
 382 };
 383
 384 /* This is the value which indicates no edge is present.  */
 385 #define EDGE_INDEX_NO_EDGE      -1
 386
 387 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 388    if there is no edge between the 2 basic blocks.  */
 389 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 390
 391 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 392    block which is either the pred or succ end of the indexed edge.  */
 393 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 394 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 395
 396 /* INDEX_EDGE returns a pointer to the edge.  */
 397 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 398
 399 /* Number of edges in the compressed edge list.  */
 400 #define NUM_EDGES(el)                   ((el)->num_edges)
 401
 402 struct edge_list * create_edge_list     PARAMS ((void));
 403 void free_edge_list                     PARAMS ((struct edge_list *));
 404 void print_edge_list                    PARAMS ((FILE *, struct edge_list *));
 405 void verify_edge_list                   PARAMS ((FILE *, struct edge_list *));
 406 int find_edge_index                     PARAMS ((struct edge_list *,
 407                                                  basic_block, basic_block));
 408
 409 extern void compute_flow_dominators     PARAMS ((sbitmap *, sbitmap *));
 410 extern void compute_immediate_dominators        PARAMS ((int *, sbitmap *));
 411
 412
 413 enum update_life_extent
 414 {
 415   UPDATE_LIFE_LOCAL = 0,
 416   UPDATE_LIFE_GLOBAL = 1,
 417   UPDATE_LIFE_GLOBAL_RM_NOTES = 2
 418 };
 419
 420 /* Flags for life_analysis and update_life_info.  */
 421
 422 #define PROP_DEATH_NOTES        1       /* Create DEAD and UNUSED notes.  */
 423 #define PROP_LOG_LINKS          2       /* Create LOG_LINKS.  */
 424 #define PROP_REG_INFO           4       /* Update regs_ever_live et al.  */
 425 #define PROP_KILL_DEAD_CODE     8       /* Remove dead code.  */
 426 #define PROP_SCAN_DEAD_CODE     16      /* Scan for dead code.  */
 427 #define PROP_AUTOINC            32      /* Create autoinc mem references.  */
 428 #define PROP_FINAL              63      /* All of the above.  */
 429
 430 extern void life_analysis       PARAMS ((rtx, FILE *, int));
 431 extern void update_life_info    PARAMS ((sbitmap, enum update_life_extent,
 432                                          int));
 433 extern int count_or_remove_death_notes  PARAMS ((sbitmap, int));
 434 extern void propagate_block     PARAMS ((basic_block, regset, regset, int));
 435
 436 struct propagate_block_info;
 437 extern rtx propagate_one_insn   PARAMS ((struct propagate_block_info *, rtx));
 438 extern struct propagate_block_info *init_propagate_block_info
 439   PARAMS ((basic_block, regset, regset, int));
 440 extern void free_propagate_block_info PARAMS ((struct propagate_block_info *));
 441
 442 /* In lcm.c */
 443 extern struct edge_list *pre_edge_lcm   PARAMS ((FILE *, int, sbitmap *,
 444                                                  sbitmap *, sbitmap *,
 445                                                  sbitmap *, sbitmap **,
 446                                                  sbitmap **));
 447 extern struct edge_list *pre_edge_rev_lcm PARAMS ((FILE *, int, sbitmap *,
 448                                                    sbitmap *, sbitmap *,
 449                                                    sbitmap *, sbitmap **,
 450                                                    sbitmap **));
 451 extern void compute_available           PARAMS ((sbitmap *, sbitmap *,
 452                                                  sbitmap *, sbitmap *));
 453 extern void optimize_mode_switching     PARAMS ((FILE *));
 454
 455 /* In emit-rtl.c.  */
 456 extern rtx emit_block_insn_after        PARAMS ((rtx, rtx, basic_block));
 457 extern rtx emit_block_insn_before       PARAMS ((rtx, rtx, basic_block));
 458
 459 /* In predict.c */
 460 extern void estimate_probability        PARAMS ((struct loops *));
 461 extern void expected_value_to_br_prob   PARAMS ((void));
 462
 463 /* In flow.c */
 464 extern void reorder_basic_blocks        PARAMS ((void));
 465 extern void dump_bb                     PARAMS ((basic_block, FILE *));
 466 extern void debug_bb                    PARAMS ((basic_block));
 467 extern void debug_bb_n                  PARAMS ((int));
 468 extern void dump_regset                 PARAMS ((regset, FILE *));
 469 extern void debug_regset                PARAMS ((regset));
 470
 471 /* This function is always defined so it can be called from the
 472    debugger, and it is declared extern so we don't get warnings about
 473    it being unused. */
 474 extern void verify_flow_info            PARAMS ((void));
 475 extern int flow_loop_outside_edge_p     PARAMS ((const struct loop *, edge));
 476
 477 typedef struct conflict_graph_def *conflict_graph;
 478
 479 /* Callback function when enumerating conflicts.  The arguments are
 480    the smaller and larger regno in the conflict.  Returns zero if
 481    enumeration is to continue, non-zero to halt enumeration.  */
 482 typedef int (*conflict_graph_enum_fn) PARAMS ((int, int, void *));
 483
 484
 485 /* Prototypes of operations on conflict graphs.  */
 486
 487 extern conflict_graph conflict_graph_new
 488                                         PARAMS ((int));
 489 extern void conflict_graph_delete       PARAMS ((conflict_graph));
 490 extern int conflict_graph_add           PARAMS ((conflict_graph,
 491                                                  int, int));
 492 extern int conflict_graph_conflict_p    PARAMS ((conflict_graph,
 493                                                  int, int));
 494 extern void conflict_graph_enum         PARAMS ((conflict_graph, int,
 495                                                  conflict_graph_enum_fn,
 496                                                  void *));
 497 extern void conflict_graph_merge_regs   PARAMS ((conflict_graph, int,
 498                                                  int));
 499 extern void conflict_graph_print        PARAMS ((conflict_graph, FILE*));
 500 extern conflict_graph conflict_graph_compute
 501                                         PARAMS ((regset,
 502                                                  partition));
 503
 504 /* In ssa.c */
 505 extern void convert_to_ssa              PARAMS ((void));
 506 extern void convert_from_ssa            PARAMS ((void));
 507 typedef int (*successor_phi_fn)         PARAMS ((rtx, int, int, void *));
 508 extern int for_each_successor_phi       PARAMS ((basic_block bb,
 509                                                  successor_phi_fn,
 510                                                  void *));
 511 extern int in_ssa_form;
 512
 513 #endif /* _BASIC_BLOCK_H */