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 regstat.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 extern void dump_reg_info (FILE *);
 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 /* Target-dependent globals.  */
 244 struct target_regs {
 245   /* For each starting hard register, the number of consecutive hard
 246      registers that a given machine mode occupies.  */
 247   unsigned char x_hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
 248
 249   /* For each hard register, the widest mode object that it can contain.
 250      This will be a MODE_INT mode if the register can hold integers.  Otherwise
 251      it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
 252      register.  */
 253   enum machine_mode x_reg_raw_mode[FIRST_PSEUDO_REGISTER];
 254
 255   /* Vector indexed by machine mode saying whether there are regs of
 256      that mode.  */
 257   bool x_have_regs_of_mode[MAX_MACHINE_MODE];
 258
 259   /* 1 if the corresponding class contains a register of the given mode.  */
 260   char x_contains_reg_of_mode[N_REG_CLASSES][MAX_MACHINE_MODE];
 261
 262   /* Record for each mode whether we can move a register directly to or
 263      from an object of that mode in memory.  If we can't, we won't try
 264      to use that mode directly when accessing a field of that mode.  */
 265   char x_direct_load[NUM_MACHINE_MODES];
 266   char x_direct_store[NUM_MACHINE_MODES];
 267
 268   /* Record for each mode whether we can float-extend from memory.  */
 269   bool x_float_extend_from_mem[NUM_MACHINE_MODES][NUM_MACHINE_MODES];
 270 };
 271
 272 extern struct target_regs default_target_regs;
 273 #if SWITCHABLE_TARGET
 274 extern struct target_regs *this_target_regs;
 275 #else
 276 #define this_target_regs (&default_target_regs)
 277 #endif
 278
 279 #define hard_regno_nregs \
 280   (this_target_regs->x_hard_regno_nregs)
 281 #define reg_raw_mode \
 282   (this_target_regs->x_reg_raw_mode)
 283 #define have_regs_of_mode \
 284   (this_target_regs->x_have_regs_of_mode)
 285 #define contains_reg_of_mode \
 286   (this_target_regs->x_contains_reg_of_mode)
 287 #define direct_load \
 288   (this_target_regs->x_direct_load)
 289 #define direct_store \
 290   (this_target_regs->x_direct_store)
 291 #define float_extend_from_mem \
 292   (this_target_regs->x_float_extend_from_mem)
 293
 294 /* Return an exclusive upper bound on the registers occupied by hard
 295    register (reg:MODE REGNO).  */
 296
 297 static inline unsigned int
 298 end_hard_regno (enum machine_mode mode, unsigned int regno)
 299 {
 300   return regno + hard_regno_nregs[regno][(int) mode];
 301 }
 302
 303 /* Likewise for hard register X.  */
 304
 305 #define END_HARD_REGNO(X) end_hard_regno (GET_MODE (X), REGNO (X))
 306
 307 /* Likewise for hard or pseudo register X.  */
 308
 309 #define END_REGNO(X) (HARD_REGISTER_P (X) ? END_HARD_REGNO (X) : REGNO (X) + 1)
 310
 311 /* Add to REGS all the registers required to store a value of mode MODE
 312    in register REGNO.  */
 313
 314 static inline void
 315 add_to_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
 316                      unsigned int regno)
 317 {
 318   unsigned int end_regno;
 319
 320   end_regno = end_hard_regno (mode, regno);
 321   do
 322     SET_HARD_REG_BIT (*regs, regno);
 323   while (++regno < end_regno);
 324 }
 325
 326 /* Likewise, but remove the registers.  */
 327
 328 static inline void
 329 remove_from_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
 330                           unsigned int regno)
 331 {
 332   unsigned int end_regno;
 333
 334   end_regno = end_hard_regno (mode, regno);
 335   do
 336     CLEAR_HARD_REG_BIT (*regs, regno);
 337   while (++regno < end_regno);
 338 }
 339
 340 /* Return true if REGS contains the whole of (reg:MODE REGNO).  */
 341
 342 static inline bool
 343 in_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
 344                    unsigned int regno)
 345 {
 346   unsigned int end_regno;
 347
 348   gcc_assert (HARD_REGISTER_NUM_P (regno));
 349
 350   if (!TEST_HARD_REG_BIT (regs, regno))
 351     return false;
 352
 353   end_regno = end_hard_regno (mode, regno);
 354
 355   if (!HARD_REGISTER_NUM_P (end_regno - 1))
 356     return false;
 357
 358   while (++regno < end_regno)
 359     if (!TEST_HARD_REG_BIT (regs, regno))
 360       return false;
 361
 362   return true;
 363 }
 364
 365 /* Return true if (reg:MODE REGNO) includes an element of REGS.  */
 366
 367 static inline bool
 368 overlaps_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
 369                          unsigned int regno)
 370 {
 371   unsigned int end_regno;
 372
 373   if (TEST_HARD_REG_BIT (regs, regno))
 374     return true;
 375
 376   end_regno = end_hard_regno (mode, regno);
 377   while (++regno < end_regno)
 378     if (TEST_HARD_REG_BIT (regs, regno))
 379       return true;
 380
 381   return false;
 382 }
 383
 384 /* Like add_to_hard_reg_set, but use a REGNO/NREGS range instead of
 385    REGNO and MODE.  */
 386
 387 static inline void
 388 add_range_to_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 389                            int nregs)
 390 {
 391   while (nregs-- > 0)
 392     SET_HARD_REG_BIT (*regs, regno + nregs);
 393 }
 394
 395 /* Likewise, but remove the registers.  */
 396
 397 static inline void
 398 remove_range_from_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 399                                 int nregs)
 400 {
 401   while (nregs-- > 0)
 402     CLEAR_HARD_REG_BIT (*regs, regno + nregs);
 403 }
 404
 405 /* Like overlaps_hard_reg_set_p, but use a REGNO/NREGS range instead of
 406    REGNO and MODE.  */
 407 static inline bool
 408 range_overlaps_hard_reg_set_p (const HARD_REG_SET set, unsigned regno,
 409                                int nregs)
 410 {
 411   while (nregs-- > 0)
 412     if (TEST_HARD_REG_BIT (set, regno + nregs))
 413       return true;
 414   return false;
 415 }
 416
 417 /* Like in_hard_reg_set_p, but use a REGNO/NREGS range instead of
 418    REGNO and MODE.  */
 419 static inline bool
 420 range_in_hard_reg_set_p (const HARD_REG_SET set, unsigned regno, int nregs)
 421 {
 422   while (nregs-- > 0)
 423     if (!TEST_HARD_REG_BIT (set, regno + nregs))
 424       return false;
 425   return true;
 426 }
 427
 428 #endif /* GCC_REGS_H */