gcc/regs.h

   1 /* Define per-register tables for data flow info and register allocation.
   2    Copyright (C) 1987-2019 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef GCC_REGS_H
  21 #define GCC_REGS_H
  22
  23 #define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
  24
  25 /* When you only have the mode of a pseudo register before it has a hard
  26    register chosen for it, this reports the size of each hard register
  27    a pseudo in such a mode would get allocated to.  A target may
  28    override this.  */
  29
  30 #ifndef REGMODE_NATURAL_SIZE
  31 #define REGMODE_NATURAL_SIZE(MODE)      UNITS_PER_WORD
  32 #endif
  33
  34 /* Maximum register number used in this function, plus one.  */
  35
  36 extern int max_regno;
  37
  38 /* REG_N_REFS and REG_N_SETS are initialized by a call to
  39    regstat_init_n_sets_and_refs from the current values of
  40    DF_REG_DEF_COUNT and DF_REG_USE_COUNT.  REG_N_REFS and REG_N_SETS
  41    should only be used if a pass need to change these values in some
  42    magical way or the pass needs to have accurate values for these
  43    and is not using incremental df scanning.
  44
  45    At the end of a pass that uses REG_N_REFS and REG_N_SETS, a call
  46    should be made to regstat_free_n_sets_and_refs.
  47
  48    Local alloc seems to play pretty loose with these values.
  49    REG_N_REFS is set to 0 if the register is used in an asm.
  50    Furthermore, local_alloc calls regclass to hack both REG_N_REFS and
  51    REG_N_SETS for three address insns.  Other passes seem to have
  52    other special values.  */
  53
  54
  55
  56 /* Structure to hold values for REG_N_SETS (i) and REG_N_REFS (i). */
  57
  58 struct regstat_n_sets_and_refs_t
  59 {
  60   int sets;                     /* # of times (REG n) is set */
  61   int refs;                     /* # of times (REG n) is used or set */
  62 };
  63
  64 extern struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs;
  65
  66 /* Indexed by n, gives number of times (REG n) is used or set.  */
  67 static inline int
  68 REG_N_REFS (int regno)
  69 {
  70   return regstat_n_sets_and_refs[regno].refs;
  71 }
  72
  73 /* Indexed by n, gives number of times (REG n) is used or set.  */
  74 #define SET_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs = V)
  75 #define INC_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs += V)
  76
  77 /* Indexed by n, gives number of times (REG n) is set.  */
  78 static inline int
  79 REG_N_SETS (int regno)
  80 {
  81   return regstat_n_sets_and_refs[regno].sets;
  82 }
  83
  84 /* Indexed by n, gives number of times (REG n) is set.  */
  85 #define SET_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets = V)
  86 #define INC_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets += V)
  87
  88 /* Given a REG, return TRUE if the reg is a PARM_DECL, FALSE otherwise.  */
  89 extern bool reg_is_parm_p (rtx);
  90
  91 /* Functions defined in regstat.c.  */
  92 extern void regstat_init_n_sets_and_refs (void);
  93 extern void regstat_free_n_sets_and_refs (void);
  94 extern void regstat_compute_ri (void);
  95 extern void regstat_free_ri (void);
  96 extern bitmap regstat_get_setjmp_crosses (void);
  97 extern void regstat_compute_calls_crossed (void);
  98 extern void regstat_free_calls_crossed (void);
  99 extern void dump_reg_info (FILE *);
 100
 101 /* Register information indexed by register number.  This structure is
 102    initialized by calling regstat_compute_ri and is destroyed by
 103    calling regstat_free_ri.  */
 104 struct reg_info_t
 105 {
 106   int freq;                     /* # estimated frequency (REG n) is used or set */
 107   int deaths;                   /* # of times (REG n) dies */
 108   int calls_crossed;            /* # of calls (REG n) is live across */
 109   int basic_block;              /* # of basic blocks (REG n) is used in */
 110 };
 111
 112 extern struct reg_info_t *reg_info_p;
 113
 114 /* The number allocated elements of reg_info_p.  */
 115 extern size_t reg_info_p_size;
 116
 117 /* Estimate frequency of references to register N.  */
 118
 119 #define REG_FREQ(N) (reg_info_p[N].freq)
 120
 121 /* The weights for each insn varies from 0 to REG_FREQ_BASE.
 122    This constant does not need to be high, as in infrequently executed
 123    regions we want to count instructions equivalently to optimize for
 124    size instead of speed.  */
 125 #define REG_FREQ_MAX 1000
 126
 127 /* Compute register frequency from the BB frequency.  When optimizing for size,
 128    or profile driven feedback is available and the function is never executed,
 129    frequency is always equivalent.  Otherwise rescale the basic block
 130    frequency.  */
 131 #define REG_FREQ_FROM_BB(bb) (optimize_function_for_size_p (cfun)             \
 132                               ? REG_FREQ_MAX                                  \
 133                               : ((bb)->count.to_frequency (cfun)              \
 134                                 * REG_FREQ_MAX / BB_FREQ_MAX)                 \
 135                               ? ((bb)->count.to_frequency (cfun)              \
 136                                  * REG_FREQ_MAX / BB_FREQ_MAX)                \
 137                               : 1)
 138
 139 /* Indexed by N, gives number of insns in which register N dies.
 140    Note that if register N is live around loops, it can die
 141    in transitions between basic blocks, and that is not counted here.
 142    So this is only a reliable indicator of how many regions of life there are
 143    for registers that are contained in one basic block.  */
 144
 145 #define REG_N_DEATHS(N) (reg_info_p[N].deaths)
 146
 147 /* Get the number of consecutive words required to hold pseudo-reg N.  */
 148
 149 #define PSEUDO_REGNO_SIZE(N) \
 150   ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1)         \
 151    / UNITS_PER_WORD)
 152
 153 /* Get the number of bytes required to hold pseudo-reg N.  */
 154
 155 #define PSEUDO_REGNO_BYTES(N) \
 156   GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
 157
 158 /* Get the machine mode of pseudo-reg N.  */
 159
 160 #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
 161
 162 /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live.  */
 163
 164 #define REG_N_CALLS_CROSSED(N)  (reg_info_p[N].calls_crossed)
 165
 166 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 167    If the value is REG_BLOCK_GLOBAL (-1),
 168    it means (REG n) is used in more than one basic block.
 169    REG_BLOCK_UNKNOWN (0) means it hasn't been seen yet so we don't know.
 170    This information remains valid for the rest of the compilation
 171    of the current function; it is used to control register allocation.  */
 172
 173 #define REG_BLOCK_UNKNOWN 0
 174 #define REG_BLOCK_GLOBAL -1
 175
 176 #define REG_BASIC_BLOCK(N) (reg_info_p[N].basic_block)
 177
 178 /* Vector of substitutions of register numbers,
 179    used to map pseudo regs into hardware regs.
 180
 181    This can't be folded into reg_n_info without changing all of the
 182    machine dependent directories, since the reload functions
 183    in the machine dependent files access it.  */
 184
 185 extern short *reg_renumber;
 186
 187 /* Flag set by local-alloc or global-alloc if they decide to allocate
 188    something in a call-clobbered register.  */
 189
 190 extern int caller_save_needed;
 191
 192 /* Select a register mode required for caller save of hard regno REGNO.  */
 193 #ifndef HARD_REGNO_CALLER_SAVE_MODE
 194 #define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \
 195   choose_hard_reg_mode (REGNO, NREGS, false)
 196 #endif
 197
 198 /* Target-dependent globals.  */
 199 struct target_regs {
 200   /* For each starting hard register, the number of consecutive hard
 201      registers that a given machine mode occupies.  */
 202   unsigned char x_hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
 203
 204   /* For each hard register, the widest mode object that it can contain.
 205      This will be a MODE_INT mode if the register can hold integers.  Otherwise
 206      it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
 207      register.  */
 208   machine_mode x_reg_raw_mode[FIRST_PSEUDO_REGISTER];
 209
 210   /* Vector indexed by machine mode saying whether there are regs of
 211      that mode.  */
 212   bool x_have_regs_of_mode[MAX_MACHINE_MODE];
 213
 214   /* 1 if the corresponding class contains a register of the given mode.  */
 215   char x_contains_reg_of_mode[N_REG_CLASSES][MAX_MACHINE_MODE];
 216
 217   /* 1 if the corresponding class contains a register of the given mode
 218      which is not global and can therefore be allocated.  */
 219   char x_contains_allocatable_reg_of_mode[N_REG_CLASSES][MAX_MACHINE_MODE];
 220
 221   /* Record for each mode whether we can move a register directly to or
 222      from an object of that mode in memory.  If we can't, we won't try
 223      to use that mode directly when accessing a field of that mode.  */
 224   char x_direct_load[NUM_MACHINE_MODES];
 225   char x_direct_store[NUM_MACHINE_MODES];
 226
 227   /* Record for each mode whether we can float-extend from memory.  */
 228   bool x_float_extend_from_mem[NUM_MACHINE_MODES][NUM_MACHINE_MODES];
 229 };
 230
 231 extern struct target_regs default_target_regs;
 232 #if SWITCHABLE_TARGET
 233 extern struct target_regs *this_target_regs;
 234 #else
 235 #define this_target_regs (&default_target_regs)
 236 #endif
 237 #define reg_raw_mode \
 238   (this_target_regs->x_reg_raw_mode)
 239 #define have_regs_of_mode \
 240   (this_target_regs->x_have_regs_of_mode)
 241 #define contains_reg_of_mode \
 242   (this_target_regs->x_contains_reg_of_mode)
 243 #define contains_allocatable_reg_of_mode \
 244   (this_target_regs->x_contains_allocatable_reg_of_mode)
 245 #define direct_load \
 246   (this_target_regs->x_direct_load)
 247 #define direct_store \
 248   (this_target_regs->x_direct_store)
 249 #define float_extend_from_mem \
 250   (this_target_regs->x_float_extend_from_mem)
 251
 252 /* Return the number of hard registers in (reg:MODE REGNO).  */
 253
 254 ALWAYS_INLINE unsigned char
 255 hard_regno_nregs (unsigned int regno, machine_mode mode)
 256 {
 257   return this_target_regs->x_hard_regno_nregs[regno][mode];
 258 }
 259
 260 /* Return an exclusive upper bound on the registers occupied by hard
 261    register (reg:MODE REGNO).  */
 262
 263 static inline unsigned int
 264 end_hard_regno (machine_mode mode, unsigned int regno)
 265 {
 266   return regno + hard_regno_nregs (regno, mode);
 267 }
 268
 269 /* Add to REGS all the registers required to store a value of mode MODE
 270    in register REGNO.  */
 271
 272 static inline void
 273 add_to_hard_reg_set (HARD_REG_SET *regs, machine_mode mode,
 274                      unsigned int regno)
 275 {
 276   unsigned int end_regno;
 277
 278   end_regno = end_hard_regno (mode, regno);
 279   do
 280     SET_HARD_REG_BIT (*regs, regno);
 281   while (++regno < end_regno);
 282 }
 283
 284 /* Likewise, but remove the registers.  */
 285
 286 static inline void
 287 remove_from_hard_reg_set (HARD_REG_SET *regs, machine_mode mode,
 288                           unsigned int regno)
 289 {
 290   unsigned int end_regno;
 291
 292   end_regno = end_hard_regno (mode, regno);
 293   do
 294     CLEAR_HARD_REG_BIT (*regs, regno);
 295   while (++regno < end_regno);
 296 }
 297
 298 /* Return true if REGS contains the whole of (reg:MODE REGNO).  */
 299
 300 static inline bool
 301 in_hard_reg_set_p (const HARD_REG_SET regs, machine_mode mode,
 302                    unsigned int regno)
 303 {
 304   unsigned int end_regno;
 305
 306   gcc_assert (HARD_REGISTER_NUM_P (regno));
 307
 308   if (!TEST_HARD_REG_BIT (regs, regno))
 309     return false;
 310
 311   end_regno = end_hard_regno (mode, regno);
 312
 313   if (!HARD_REGISTER_NUM_P (end_regno - 1))
 314     return false;
 315
 316   while (++regno < end_regno)
 317     if (!TEST_HARD_REG_BIT (regs, regno))
 318       return false;
 319
 320   return true;
 321 }
 322
 323 /* Return true if (reg:MODE REGNO) includes an element of REGS.  */
 324
 325 static inline bool
 326 overlaps_hard_reg_set_p (const HARD_REG_SET regs, machine_mode mode,
 327                          unsigned int regno)
 328 {
 329   unsigned int end_regno;
 330
 331   if (TEST_HARD_REG_BIT (regs, regno))
 332     return true;
 333
 334   end_regno = end_hard_regno (mode, regno);
 335   while (++regno < end_regno)
 336     if (TEST_HARD_REG_BIT (regs, regno))
 337       return true;
 338
 339   return false;
 340 }
 341
 342 /* Like add_to_hard_reg_set, but use a REGNO/NREGS range instead of
 343    REGNO and MODE.  */
 344
 345 static inline void
 346 add_range_to_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 347                            int nregs)
 348 {
 349   while (nregs-- > 0)
 350     SET_HARD_REG_BIT (*regs, regno + nregs);
 351 }
 352
 353 /* Likewise, but remove the registers.  */
 354
 355 static inline void
 356 remove_range_from_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 357                                 int nregs)
 358 {
 359   while (nregs-- > 0)
 360     CLEAR_HARD_REG_BIT (*regs, regno + nregs);
 361 }
 362
 363 /* Like overlaps_hard_reg_set_p, but use a REGNO/NREGS range instead of
 364    REGNO and MODE.  */
 365 static inline bool
 366 range_overlaps_hard_reg_set_p (const HARD_REG_SET set, unsigned regno,
 367                                int nregs)
 368 {
 369   while (nregs-- > 0)
 370     if (TEST_HARD_REG_BIT (set, regno + nregs))
 371       return true;
 372   return false;
 373 }
 374
 375 /* Like in_hard_reg_set_p, but use a REGNO/NREGS range instead of
 376    REGNO and MODE.  */
 377 static inline bool
 378 range_in_hard_reg_set_p (const HARD_REG_SET set, unsigned regno, int nregs)
 379 {
 380   while (nregs-- > 0)
 381     if (!TEST_HARD_REG_BIT (set, regno + nregs))
 382       return false;
 383   return true;
 384 }
 385
 386 /* Get registers used by given function call instruction.  */
 387 extern bool get_call_reg_set_usage (rtx_insn *insn, HARD_REG_SET *reg_set,
 388                                     HARD_REG_SET default_set);
 389
 390 #endif /* GCC_REGS_H */