gcc/regs.h

   1 /* Define per-register tables for data flow info and register allocation.
   2    Copyright (C) 1987, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2003, 2004, 2005, 2006, 2007, 2008, 2010 Free Software
   4    Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #ifndef GCC_REGS_H
  23 #define GCC_REGS_H
  24
  25 #include "machmode.h"
  26 #include "hard-reg-set.h"
  27 #include "rtl.h"
  28
  29 #define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
  30
  31 /* When you only have the mode of a pseudo register before it has a hard
  32    register chosen for it, this reports the size of each hard register
  33    a pseudo in such a mode would get allocated to.  A target may
  34    override this.  */
  35
  36 #ifndef REGMODE_NATURAL_SIZE
  37 #define REGMODE_NATURAL_SIZE(MODE)      UNITS_PER_WORD
  38 #endif
  39
  40 /* Maximum register number used in this function, plus one.  */
  41
  42 extern int max_regno;
  43
  44 /* REG_N_REFS and REG_N_SETS are initialized by a call to
  45    regstat_init_n_sets_and_refs from the current values of
  46    DF_REG_DEF_COUNT and DF_REG_USE_COUNT.  REG_N_REFS and REG_N_SETS
  47    should only be used if a pass need to change these values in some
  48    magical way or the pass needs to have accurate values for these
  49    and is not using incremental df scanning.
  50
  51    At the end of a pass that uses REG_N_REFS and REG_N_SETS, a call
  52    should be made to regstat_free_n_sets_and_refs.
  53
  54    Local alloc seems to play pretty loose with these values.
  55    REG_N_REFS is set to 0 if the register is used in an asm.
  56    Furthermore, local_alloc calls regclass to hack both REG_N_REFS and
  57    REG_N_SETS for three address insns.  Other passes seem to have
  58    other special values.  */
  59
  60
  61
  62 /* Structure to hold values for REG_N_SETS (i) and REG_N_REFS (i). */
  63
  64 struct regstat_n_sets_and_refs_t
  65 {
  66   int sets;                     /* # of times (REG n) is set */
  67   int refs;                     /* # of times (REG n) is used or set */
  68 };
  69
  70 extern struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs;
  71
  72 /* Indexed by n, gives number of times (REG n) is used or set.  */
  73 static inline int
  74 REG_N_REFS(int regno)
  75 {
  76   return regstat_n_sets_and_refs[regno].refs;
  77 }
  78
  79 /* Indexed by n, gives number of times (REG n) is used or set.  */
  80 #define SET_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs = V)
  81 #define INC_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs += V)
  82
  83 /* Indexed by n, gives number of times (REG n) is set.  */
  84 static inline int
  85 REG_N_SETS (int regno)
  86 {
  87   return regstat_n_sets_and_refs[regno].sets;
  88 }
  89
  90 /* Indexed by n, gives number of times (REG n) is set.  */
  91 #define SET_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets = V)
  92 #define INC_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets += V)
  93
  94
  95 /* Functions defined in reg-stat.c.  */
  96 extern void regstat_init_n_sets_and_refs (void);
  97 extern void regstat_free_n_sets_and_refs (void);
  98 extern void regstat_compute_ri (void);
  99 extern void regstat_free_ri (void);
 100 extern bitmap regstat_get_setjmp_crosses (void);
 101 extern void regstat_compute_calls_crossed (void);
 102 extern void regstat_free_calls_crossed (void);
 103
 104
 105 /* Register information indexed by register number.  This structure is
 106    initialized by calling regstat_compute_ri and is destroyed by
 107    calling regstat_free_ri.  */
 108 struct reg_info_t
 109 {
 110   int freq;                     /* # estimated frequency (REG n) is used or set */
 111   int deaths;                   /* # of times (REG n) dies */
 112   int live_length;              /* # of instructions (REG n) is live */
 113   int calls_crossed;            /* # of calls (REG n) is live across */
 114   int freq_calls_crossed;       /* # estimated frequency (REG n) crosses call */
 115   int throw_calls_crossed;      /* # of calls that may throw (REG n) is live across */
 116   int basic_block;              /* # of basic blocks (REG n) is used in */
 117 };
 118
 119 extern struct reg_info_t *reg_info_p;
 120
 121 /* The number allocated elements of reg_info_p.  */
 122 extern size_t reg_info_p_size;
 123
 124 /* Estimate frequency of references to register N.  */
 125
 126 #define REG_FREQ(N) (reg_info_p[N].freq)
 127
 128 /* The weights for each insn varies from 0 to REG_FREQ_BASE.
 129    This constant does not need to be high, as in infrequently executed
 130    regions we want to count instructions equivalently to optimize for
 131    size instead of speed.  */
 132 #define REG_FREQ_MAX 1000
 133
 134 /* Compute register frequency from the BB frequency.  When optimizing for size,
 135    or profile driven feedback is available and the function is never executed,
 136    frequency is always equivalent.  Otherwise rescale the basic block
 137    frequency.  */
 138 #define REG_FREQ_FROM_BB(bb) (optimize_size                                   \
 139                               || (flag_branch_probabilities                   \
 140                                   && !ENTRY_BLOCK_PTR->count)                 \
 141                               ? REG_FREQ_MAX                                  \
 142                               : ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
 143                               ? ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
 144                               : 1)
 145
 146 /* Indexed by N, gives number of insns in which register N dies.
 147    Note that if register N is live around loops, it can die
 148    in transitions between basic blocks, and that is not counted here.
 149    So this is only a reliable indicator of how many regions of life there are
 150    for registers that are contained in one basic block.  */
 151
 152 #define REG_N_DEATHS(N) (reg_info_p[N].deaths)
 153
 154 /* Get the number of consecutive words required to hold pseudo-reg N.  */
 155
 156 #define PSEUDO_REGNO_SIZE(N) \
 157   ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1)         \
 158    / UNITS_PER_WORD)
 159
 160 /* Get the number of bytes required to hold pseudo-reg N.  */
 161
 162 #define PSEUDO_REGNO_BYTES(N) \
 163   GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
 164
 165 /* Get the machine mode of pseudo-reg N.  */
 166
 167 #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
 168
 169 /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live.  */
 170
 171 #define REG_N_CALLS_CROSSED(N)  (reg_info_p[N].calls_crossed)
 172 #define REG_FREQ_CALLS_CROSSED(N)  (reg_info_p[N].freq_calls_crossed)
 173
 174 /* Indexed by N, gives number of CALL_INSNS that may throw, across which
 175    (REG n) is live.  */
 176
 177 #define REG_N_THROWING_CALLS_CROSSED(N) (reg_info_p[N].throw_calls_crossed)
 178
 179 /* Total number of instructions at which (REG n) is live.  The larger
 180    this is, the less priority (REG n) gets for allocation in a hard
 181    register (in global-alloc).  This is set in df-problems.c whenever
 182    register info is requested and remains valid for the rest of the
 183    compilation of the function; it is used to control register
 184    allocation.
 185
 186    local-alloc.c may alter this number to change the priority.
 187
 188    Negative values are special.
 189    -1 is used to mark a pseudo reg which has a constant or memory equivalent
 190    and is used infrequently enough that it should not get a hard register.
 191    -2 is used to mark a pseudo reg for a parameter, when a frame pointer
 192    is not required.  global.c makes an allocno for this but does
 193    not try to assign a hard register to it.  */
 194
 195 #define REG_LIVE_LENGTH(N)  (reg_info_p[N].live_length)
 196
 197 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 198    If the value is REG_BLOCK_GLOBAL (-1),
 199    it means (REG n) is used in more than one basic block.
 200    REG_BLOCK_UNKNOWN (0) means it hasn't been seen yet so we don't know.
 201    This information remains valid for the rest of the compilation
 202    of the current function; it is used to control register allocation.  */
 203
 204 #define REG_BLOCK_UNKNOWN 0
 205 #define REG_BLOCK_GLOBAL -1
 206
 207 #define REG_BASIC_BLOCK(N) (reg_info_p[N].basic_block)
 208
 209 /* Vector of substitutions of register numbers,
 210    used to map pseudo regs into hardware regs.
 211
 212    This can't be folded into reg_n_info without changing all of the
 213    machine dependent directories, since the reload functions
 214    in the machine dependent files access it.  */
 215
 216 extern short *reg_renumber;
 217
 218 /* Flag set by local-alloc or global-alloc if they decide to allocate
 219    something in a call-clobbered register.  */
 220
 221 extern int caller_save_needed;
 222
 223 /* Predicate to decide whether to give a hard reg to a pseudo which
 224    is referenced REFS times and would need to be saved and restored
 225    around a call CALLS times.  */
 226
 227 #ifndef CALLER_SAVE_PROFITABLE
 228 #define CALLER_SAVE_PROFITABLE(REFS, CALLS)  (4 * (CALLS) < (REFS))
 229 #endif
 230
 231 /* Select a register mode required for caller save of hard regno REGNO.  */
 232 #ifndef HARD_REGNO_CALLER_SAVE_MODE
 233 #define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \
 234   choose_hard_reg_mode (REGNO, NREGS, false)
 235 #endif
 236
 237 /* Registers that get partially clobbered by a call in a given mode.
 238    These must not be call used registers.  */
 239 #ifndef HARD_REGNO_CALL_PART_CLOBBERED
 240 #define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0
 241 #endif
 242
 243 typedef unsigned short move_table[N_REG_CLASSES];
 244
 245 /* Target-dependent globals.  */
 246 struct target_regs {
 247   /* For each starting hard register, the number of consecutive hard
 248      registers that a given machine mode occupies.  */
 249   unsigned char x_hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
 250
 251   /* For each hard register, the widest mode object that it can contain.
 252      This will be a MODE_INT mode if the register can hold integers.  Otherwise
 253      it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
 254      register.  */
 255   enum machine_mode x_reg_raw_mode[FIRST_PSEUDO_REGISTER];
 256
 257   /* Vector indexed by machine mode saying whether there are regs of
 258      that mode.  */
 259   bool x_have_regs_of_mode[MAX_MACHINE_MODE];
 260
 261   /* 1 if the corresponding class contains a register of the given mode.  */
 262   char x_contains_reg_of_mode[N_REG_CLASSES][MAX_MACHINE_MODE];
 263
 264   /* Maximum cost of moving from a register in one class to a register
 265      in another class.  Based on TARGET_REGISTER_MOVE_COST.  */
 266   move_table *x_move_cost[MAX_MACHINE_MODE];
 267
 268   /* Similar, but here we don't have to move if the first index is a
 269      subset of the second so in that case the cost is zero.  */
 270   move_table *x_may_move_in_cost[MAX_MACHINE_MODE];
 271
 272   /* Similar, but here we don't have to move if the first index is a
 273      superset of the second so in that case the cost is zero.  */
 274   move_table *x_may_move_out_cost[MAX_MACHINE_MODE];
 275
 276   /* Keep track of the last mode we initialized move costs for.  */
 277   int x_last_mode_for_init_move_cost;
 278
 279   /* Record for each mode whether we can move a register directly to or
 280      from an object of that mode in memory.  If we can't, we won't try
 281      to use that mode directly when accessing a field of that mode.  */
 282   char x_direct_load[NUM_MACHINE_MODES];
 283   char x_direct_store[NUM_MACHINE_MODES];
 284
 285   /* Record for each mode whether we can float-extend from memory.  */
 286   bool x_float_extend_from_mem[NUM_MACHINE_MODES][NUM_MACHINE_MODES];
 287 };
 288
 289 extern struct target_regs default_target_regs;
 290 #if SWITCHABLE_TARGET
 291 extern struct target_regs *this_target_regs;
 292 #else
 293 #define this_target_regs (&default_target_regs)
 294 #endif
 295
 296 #define hard_regno_nregs \
 297   (this_target_regs->x_hard_regno_nregs)
 298 #define reg_raw_mode \
 299   (this_target_regs->x_reg_raw_mode)
 300 #define have_regs_of_mode \
 301   (this_target_regs->x_have_regs_of_mode)
 302 #define contains_reg_of_mode \
 303   (this_target_regs->x_contains_reg_of_mode)
 304 #define move_cost \
 305   (this_target_regs->x_move_cost)
 306 #define may_move_in_cost \
 307   (this_target_regs->x_may_move_in_cost)
 308 #define may_move_out_cost \
 309   (this_target_regs->x_may_move_out_cost)
 310 #define direct_load \
 311   (this_target_regs->x_direct_load)
 312 #define direct_store \
 313   (this_target_regs->x_direct_store)
 314 #define float_extend_from_mem \
 315   (this_target_regs->x_float_extend_from_mem)
 316
 317 /* Return an exclusive upper bound on the registers occupied by hard
 318    register (reg:MODE REGNO).  */
 319
 320 static inline unsigned int
 321 end_hard_regno (enum machine_mode mode, unsigned int regno)
 322 {
 323   return regno + hard_regno_nregs[regno][(int) mode];
 324 }
 325
 326 /* Likewise for hard register X.  */
 327
 328 #define END_HARD_REGNO(X) end_hard_regno (GET_MODE (X), REGNO (X))
 329
 330 /* Likewise for hard or pseudo register X.  */
 331
 332 #define END_REGNO(X) (HARD_REGISTER_P (X) ? END_HARD_REGNO (X) : REGNO (X) + 1)
 333
 334 /* Add to REGS all the registers required to store a value of mode MODE
 335    in register REGNO.  */
 336
 337 static inline void
 338 add_to_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
 339                      unsigned int regno)
 340 {
 341   unsigned int end_regno;
 342
 343   end_regno = end_hard_regno (mode, regno);
 344   do
 345     SET_HARD_REG_BIT (*regs, regno);
 346   while (++regno < end_regno);
 347 }
 348
 349 /* Likewise, but remove the registers.  */
 350
 351 static inline void
 352 remove_from_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
 353                           unsigned int regno)
 354 {
 355   unsigned int end_regno;
 356
 357   end_regno = end_hard_regno (mode, regno);
 358   do
 359     CLEAR_HARD_REG_BIT (*regs, regno);
 360   while (++regno < end_regno);
 361 }
 362
 363 /* Return true if REGS contains the whole of (reg:MODE REGNO).  */
 364
 365 static inline bool
 366 in_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
 367                    unsigned int regno)
 368 {
 369   unsigned int end_regno;
 370
 371   gcc_assert (HARD_REGISTER_NUM_P (regno));
 372
 373   if (!TEST_HARD_REG_BIT (regs, regno))
 374     return false;
 375
 376   end_regno = end_hard_regno (mode, regno);
 377
 378   if (!HARD_REGISTER_NUM_P (end_regno - 1))
 379     return false;
 380
 381   while (++regno < end_regno)
 382     if (!TEST_HARD_REG_BIT (regs, regno))
 383       return false;
 384
 385   return true;
 386 }
 387
 388 /* Return true if (reg:MODE REGNO) includes an element of REGS.  */
 389
 390 static inline bool
 391 overlaps_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
 392                          unsigned int regno)
 393 {
 394   unsigned int end_regno;
 395
 396   if (TEST_HARD_REG_BIT (regs, regno))
 397     return true;
 398
 399   end_regno = end_hard_regno (mode, regno);
 400   while (++regno < end_regno)
 401     if (TEST_HARD_REG_BIT (regs, regno))
 402       return true;
 403
 404   return false;
 405 }
 406
 407 /* Like add_to_hard_reg_set, but use a REGNO/NREGS range instead of
 408    REGNO and MODE.  */
 409
 410 static inline void
 411 add_range_to_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 412                            int nregs)
 413 {
 414   while (nregs-- > 0)
 415     SET_HARD_REG_BIT (*regs, regno + nregs);
 416 }
 417
 418 /* Likewise, but remove the registers.  */
 419
 420 static inline void
 421 remove_range_from_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 422                                 int nregs)
 423 {
 424   while (nregs-- > 0)
 425     CLEAR_HARD_REG_BIT (*regs, regno + nregs);
 426 }
 427
 428 /* Like overlaps_hard_reg_set_p, but use a REGNO/NREGS range instead of
 429    REGNO and MODE.  */
 430 static inline bool
 431 range_overlaps_hard_reg_set_p (const HARD_REG_SET set, unsigned regno,
 432                                int nregs)
 433 {
 434   while (nregs-- > 0)
 435     if (TEST_HARD_REG_BIT (set, regno + nregs))
 436       return true;
 437   return false;
 438 }
 439
 440 /* Like in_hard_reg_set_p, but use a REGNO/NREGS range instead of
 441    REGNO and MODE.  */
 442 static inline bool
 443 range_in_hard_reg_set_p (const HARD_REG_SET set, unsigned regno, int nregs)
 444 {
 445   while (nregs-- > 0)
 446     if (!TEST_HARD_REG_BIT (set, regno + nregs))
 447       return false;
 448   return true;
 449 }
 450
 451 #endif /* GCC_REGS_H */