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