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 redirect_edge_succ          PARAMS ((edge, basic_block));
 236 extern void redirect_edge_pred          PARAMS ((edge, basic_block));
 237 extern void create_basic_block          PARAMS ((int, rtx, rtx, rtx));
 238 extern int flow_delete_block            PARAMS ((basic_block));
 239 extern void merge_blocks_nomove         PARAMS ((basic_block, basic_block));
 240 extern void tidy_fallthru_edge          PARAMS ((edge, basic_block,
 241                                                  basic_block));
 242
 243 /* Structure to hold information for each natural loop.  */
 244 struct loop
 245 {
 246   int num;
 247
 248   /* Basic block of loop header.  */
 249   basic_block header;
 250
 251   /* Basic block of loop latch.  */
 252   basic_block latch;
 253
 254   /* Basic block of loop pre-header or NULL if it does not exist.  */
 255   basic_block pre_header;
 256
 257   /* The first block in the loop.  This is not necessarily the same as
 258      the loop header.  */
 259   basic_block first;
 260
 261   /* The last block in the loop.  This is not necessarily the same as
 262      the loop latch.  */
 263   basic_block last;
 264
 265   /* Bitmap of blocks contained within the loop.  */
 266   sbitmap nodes;
 267
 268   /* Number of blocks contained within the loop.  */
 269   int num_nodes;
 270
 271   /* Array of edges that exit the loop.  */
 272   edge *exits;
 273
 274   /* Number of edges that exit the loop.  */
 275   int num_exits;
 276
 277   /* The loop nesting depth.  */
 278   int depth;
 279
 280   /* The height of the loop (enclosed loop levels) within the loop
 281      hierarchy tree.  */
 282   int level;
 283
 284   /* The outer (parent) loop or NULL if outermost loop.  */
 285   struct loop *outer;
 286
 287   /* The first inner (child) loop or NULL if innermost loop.  */
 288   struct loop *inner;
 289
 290   /* Link to the next (sibling) loop.  */
 291   struct loop *next;
 292
 293   /* Non-zero if the loop shares a header with another loop.  */
 294   int shared;
 295
 296   /* Non-zero if the loop is invalid (e.g., contains setjmp.).  */
 297   int invalid;
 298
 299   /* Auxiliary info specific to a pass.  */
 300   void *aux;
 301
 302   /* The following are currently used by loop.c but they are likely to
 303      disappear as loop.c is converted to use the CFG.  */
 304
 305   /* Non-zero if the loop has a NOTE_INSN_LOOP_VTOP.  */
 306   rtx vtop;
 307
 308   /* Non-zero if the loop has a NOTE_INSN_LOOP_CONT.
 309      A continue statement will generate a branch to NEXT_INSN (cont).  */
 310   rtx cont;
 311
 312   /* The dominator of cont.  */
 313   rtx cont_dominator;
 314
 315   /* The NOTE_INSN_LOOP_BEG.  */
 316   rtx start;
 317
 318   /* The NOTE_INSN_LOOP_END.  */
 319   rtx end;
 320
 321   /* For a rotated loop that is entered near the bottom,
 322      this is the label at the top.  Otherwise it is zero.  */
 323   rtx top;
 324
 325   /* Place in the loop where control enters.  */
 326   rtx scan_start;
 327
 328   /* List of all LABEL_REFs which refer to code labels outside the
 329      loop.  Used by routines that need to know all loop exits, such as
 330      final_biv_value and final_giv_value.
 331
 332      This does not include loop exits due to return instructions.
 333      This is because all bivs and givs are pseudos, and hence must be
 334      dead after a return, so the presense of a return does not affect
 335      any of the optimizations that use this info.  It is simpler to
 336      just not include return instructions on this list.  */
 337   rtx exit_labels;
 338
 339   /* The number of LABEL_REFs on exit_labels for this loop and all
 340      loops nested inside it.  */
 341   int exit_count;
 342 };
 343
 344
 345 /* Structure to hold CFG information about natural loops within a function.  */
 346 struct loops
 347 {
 348   /* Number of natural loops in the function.  */
 349   int num;
 350
 351   /* Maxium nested loop level in the function.  */
 352   int levels;
 353
 354   /* Array of natural loop descriptors (scanning this array in reverse order
 355      will find the inner loops before their enclosing outer loops).  */
 356   struct loop *array;
 357
 358   /* Pointer to root of loop heirachy tree.  */
 359   struct loop *tree;
 360
 361   /* Information derived from the CFG.  */
 362   struct cfg
 363   {
 364     /* The bitmap vector of dominators or NULL if not computed.  */
 365     sbitmap *dom;
 366
 367     /* The ordering of the basic blocks in a depth first search.  */
 368     int *dfs_order;
 369   } cfg;
 370
 371   /* Headers shared by multiple loops that should be merged.  */
 372   sbitmap shared_headers;
 373 };
 374
 375 extern int flow_loops_find PARAMS ((struct loops *));
 376 extern void flow_loops_free PARAMS ((struct loops *));
 377 extern void flow_loops_dump PARAMS ((const struct loops *, FILE *, int));
 378
 379
 380 /* This structure maintains an edge list vector.  */
 381 struct edge_list
 382 {
 383   int num_blocks;
 384   int num_edges;
 385   edge *index_to_edge;
 386 };
 387
 388 /* This is the value which indicates no edge is present.  */
 389 #define EDGE_INDEX_NO_EDGE      -1
 390
 391 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 392    if there is no edge between the 2 basic blocks.  */
 393 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 394
 395 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 396    block which is either the pred or succ end of the indexed edge.  */
 397 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 398 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 399
 400 /* INDEX_EDGE returns a pointer to the edge.  */
 401 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 402
 403 /* Number of edges in the compressed edge list.  */
 404 #define NUM_EDGES(el)                   ((el)->num_edges)
 405
 406 struct edge_list * create_edge_list     PARAMS ((void));
 407 void free_edge_list                     PARAMS ((struct edge_list *));
 408 void print_edge_list                    PARAMS ((FILE *, struct edge_list *));
 409 void verify_edge_list                   PARAMS ((FILE *, struct edge_list *));
 410 int find_edge_index                     PARAMS ((struct edge_list *,
 411                                                  basic_block, basic_block));
 412
 413 extern void compute_flow_dominators     PARAMS ((sbitmap *, sbitmap *));
 414 extern void compute_immediate_dominators        PARAMS ((int *, sbitmap *));
 415
 416
 417 enum update_life_extent
 418 {
 419   UPDATE_LIFE_LOCAL = 0,
 420   UPDATE_LIFE_GLOBAL = 1,
 421   UPDATE_LIFE_GLOBAL_RM_NOTES = 2
 422 };
 423
 424 /* Flags for life_analysis and update_life_info.  */
 425
 426 #define PROP_DEATH_NOTES        1       /* Create DEAD and UNUSED notes.  */
 427 #define PROP_LOG_LINKS          2       /* Create LOG_LINKS.  */
 428 #define PROP_REG_INFO           4       /* Update regs_ever_live et al.  */
 429 #define PROP_KILL_DEAD_CODE     8       /* Remove dead code.  */
 430 #define PROP_SCAN_DEAD_CODE     16      /* Scan for dead code.  */
 431 #define PROP_AUTOINC            32      /* Create autoinc mem references.  */
 432 #define PROP_FINAL              63      /* All of the above.  */
 433
 434 extern void life_analysis       PARAMS ((rtx, FILE *, int));
 435 extern void update_life_info    PARAMS ((sbitmap, enum update_life_extent,
 436                                          int));
 437 extern int count_or_remove_death_notes  PARAMS ((sbitmap, int));
 438 extern void propagate_block     PARAMS ((basic_block, regset, regset, int));
 439
 440 struct propagate_block_info;
 441 extern rtx propagate_one_insn   PARAMS ((struct propagate_block_info *, rtx));
 442 extern struct propagate_block_info *init_propagate_block_info
 443   PARAMS ((basic_block, regset, regset, int));
 444 extern void free_propagate_block_info PARAMS ((struct propagate_block_info *));
 445
 446 /* In lcm.c */
 447 extern struct edge_list *pre_edge_lcm   PARAMS ((FILE *, int, sbitmap *,
 448                                                  sbitmap *, sbitmap *,
 449                                                  sbitmap *, sbitmap **,
 450                                                  sbitmap **));
 451 extern struct edge_list *pre_edge_rev_lcm PARAMS ((FILE *, int, sbitmap *,
 452                                                    sbitmap *, sbitmap *,
 453                                                    sbitmap *, sbitmap **,
 454                                                    sbitmap **));
 455 extern void compute_available           PARAMS ((sbitmap *, sbitmap *,
 456                                                  sbitmap *, sbitmap *));
 457 extern int optimize_mode_switching      PARAMS ((FILE *));
 458
 459 /* In emit-rtl.c.  */
 460 extern rtx emit_block_insn_after        PARAMS ((rtx, rtx, basic_block));
 461 extern rtx emit_block_insn_before       PARAMS ((rtx, rtx, basic_block));
 462
 463 /* In predict.c */
 464 extern void estimate_probability        PARAMS ((struct loops *));
 465 extern void expected_value_to_br_prob   PARAMS ((void));
 466
 467 /* In flow.c */
 468 extern void reorder_basic_blocks        PARAMS ((void));
 469 extern void dump_bb                     PARAMS ((basic_block, FILE *));
 470 extern void debug_bb                    PARAMS ((basic_block));
 471 extern void debug_bb_n                  PARAMS ((int));
 472 extern void dump_regset                 PARAMS ((regset, FILE *));
 473 extern void debug_regset                PARAMS ((regset));
 474
 475 /* This function is always defined so it can be called from the
 476    debugger, and it is declared extern so we don't get warnings about
 477    it being unused. */
 478 extern void verify_flow_info            PARAMS ((void));
 479 extern int flow_loop_outside_edge_p     PARAMS ((const struct loop *, edge));
 480
 481 typedef struct conflict_graph_def *conflict_graph;
 482
 483 /* Callback function when enumerating conflicts.  The arguments are
 484    the smaller and larger regno in the conflict.  Returns zero if
 485    enumeration is to continue, non-zero to halt enumeration.  */
 486 typedef int (*conflict_graph_enum_fn) PARAMS ((int, int, void *));
 487
 488
 489 /* Prototypes of operations on conflict graphs.  */
 490
 491 extern conflict_graph conflict_graph_new
 492                                         PARAMS ((int));
 493 extern void conflict_graph_delete       PARAMS ((conflict_graph));
 494 extern int conflict_graph_add           PARAMS ((conflict_graph,
 495                                                  int, int));
 496 extern int conflict_graph_conflict_p    PARAMS ((conflict_graph,
 497                                                  int, int));
 498 extern void conflict_graph_enum         PARAMS ((conflict_graph, int,
 499                                                  conflict_graph_enum_fn,
 500                                                  void *));
 501 extern void conflict_graph_merge_regs   PARAMS ((conflict_graph, int,
 502                                                  int));
 503 extern void conflict_graph_print        PARAMS ((conflict_graph, FILE*));
 504 extern conflict_graph conflict_graph_compute
 505                                         PARAMS ((regset,
 506                                                  partition));
 507
 508 /* In ssa.c */
 509 extern void convert_to_ssa              PARAMS ((void));
 510 extern void convert_from_ssa            PARAMS ((void));
 511 typedef int (*successor_phi_fn)         PARAMS ((rtx, int, int, void *));
 512 extern int for_each_successor_phi       PARAMS ((basic_block bb,
 513                                                  successor_phi_fn,
 514                                                  void *));
 515 extern int in_ssa_form;
 516
 517 #endif /* _BASIC_BLOCK_H */