gcc/regs.h

   1 /* Define per-register tables for data flow info and register allocation.
   2    Copyright (C) 1987-2017 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)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
 134                               ? ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
 135                               : 1)
 136
 137 /* Indexed by N, gives number of insns in which register N dies.
 138    Note that if register N is live around loops, it can die
 139    in transitions between basic blocks, and that is not counted here.
 140    So this is only a reliable indicator of how many regions of life there are
 141    for registers that are contained in one basic block.  */
 142
 143 #define REG_N_DEATHS(N) (reg_info_p[N].deaths)
 144
 145 /* Get the number of consecutive words required to hold pseudo-reg N.  */
 146
 147 #define PSEUDO_REGNO_SIZE(N) \
 148   ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1)         \
 149    / UNITS_PER_WORD)
 150
 151 /* Get the number of bytes required to hold pseudo-reg N.  */
 152
 153 #define PSEUDO_REGNO_BYTES(N) \
 154   GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
 155
 156 /* Get the machine mode of pseudo-reg N.  */
 157
 158 #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
 159
 160 /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live.  */
 161
 162 #define REG_N_CALLS_CROSSED(N)  (reg_info_p[N].calls_crossed)
 163
 164 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 165    If the value is REG_BLOCK_GLOBAL (-1),
 166    it means (REG n) is used in more than one basic block.
 167    REG_BLOCK_UNKNOWN (0) means it hasn't been seen yet so we don't know.
 168    This information remains valid for the rest of the compilation
 169    of the current function; it is used to control register allocation.  */
 170
 171 #define REG_BLOCK_UNKNOWN 0
 172 #define REG_BLOCK_GLOBAL -1
 173
 174 #define REG_BASIC_BLOCK(N) (reg_info_p[N].basic_block)
 175
 176 /* Vector of substitutions of register numbers,
 177    used to map pseudo regs into hardware regs.
 178
 179    This can't be folded into reg_n_info without changing all of the
 180    machine dependent directories, since the reload functions
 181    in the machine dependent files access it.  */
 182
 183 extern short *reg_renumber;
 184
 185 /* Flag set by local-alloc or global-alloc if they decide to allocate
 186    something in a call-clobbered register.  */
 187
 188 extern int caller_save_needed;
 189
 190 /* Select a register mode required for caller save of hard regno REGNO.  */
 191 #ifndef HARD_REGNO_CALLER_SAVE_MODE
 192 #define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \
 193   choose_hard_reg_mode (REGNO, NREGS, false)
 194 #endif
 195
 196 /* Registers that get partially clobbered by a call in a given mode.
 197    These must not be call used registers.  */
 198 #ifndef HARD_REGNO_CALL_PART_CLOBBERED
 199 #define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0
 200 #endif
 201
 202 /* Target-dependent globals.  */
 203 struct target_regs {
 204   /* For each starting hard register, the number of consecutive hard
 205      registers that a given machine mode occupies.  */
 206   unsigned char x_hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
 207
 208   /* For each hard register, the widest mode object that it can contain.
 209      This will be a MODE_INT mode if the register can hold integers.  Otherwise
 210      it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
 211      register.  */
 212   machine_mode x_reg_raw_mode[FIRST_PSEUDO_REGISTER];
 213
 214   /* Vector indexed by machine mode saying whether there are regs of
 215      that mode.  */
 216   bool x_have_regs_of_mode[MAX_MACHINE_MODE];
 217
 218   /* 1 if the corresponding class contains a register of the given mode.  */
 219   char x_contains_reg_of_mode[N_REG_CLASSES][MAX_MACHINE_MODE];
 220
 221   /* 1 if the corresponding class contains a register of the given mode
 222      which is not global and can therefore be allocated.  */
 223   char x_contains_allocatable_reg_of_mode[N_REG_CLASSES][MAX_MACHINE_MODE];
 224
 225   /* Record for each mode whether we can move a register directly to or
 226      from an object of that mode in memory.  If we can't, we won't try
 227      to use that mode directly when accessing a field of that mode.  */
 228   char x_direct_load[NUM_MACHINE_MODES];
 229   char x_direct_store[NUM_MACHINE_MODES];
 230
 231   /* Record for each mode whether we can float-extend from memory.  */
 232   bool x_float_extend_from_mem[NUM_MACHINE_MODES][NUM_MACHINE_MODES];
 233 };
 234
 235 extern struct target_regs default_target_regs;
 236 #if SWITCHABLE_TARGET
 237 extern struct target_regs *this_target_regs;
 238 #else
 239 #define this_target_regs (&default_target_regs)
 240 #endif
 241
 242 #define hard_regno_nregs \
 243   (this_target_regs->x_hard_regno_nregs)
 244 #define reg_raw_mode \
 245   (this_target_regs->x_reg_raw_mode)
 246 #define have_regs_of_mode \
 247   (this_target_regs->x_have_regs_of_mode)
 248 #define contains_reg_of_mode \
 249   (this_target_regs->x_contains_reg_of_mode)
 250 #define contains_allocatable_reg_of_mode \
 251   (this_target_regs->x_contains_allocatable_reg_of_mode)
 252 #define direct_load \
 253   (this_target_regs->x_direct_load)
 254 #define direct_store \
 255   (this_target_regs->x_direct_store)
 256 #define float_extend_from_mem \
 257   (this_target_regs->x_float_extend_from_mem)
 258
 259 /* Return an exclusive upper bound on the registers occupied by hard
 260    register (reg:MODE REGNO).  */
 261
 262 static inline unsigned int
 263 end_hard_regno (machine_mode mode, unsigned int regno)
 264 {
 265   return regno + hard_regno_nregs[regno][(int) mode];
 266 }
 267
 268 /* Add to REGS all the registers required to store a value of mode MODE
 269    in register REGNO.  */
 270
 271 static inline void
 272 add_to_hard_reg_set (HARD_REG_SET *regs, machine_mode mode,
 273                      unsigned int regno)
 274 {
 275   unsigned int end_regno;
 276
 277   end_regno = end_hard_regno (mode, regno);
 278   do
 279     SET_HARD_REG_BIT (*regs, regno);
 280   while (++regno < end_regno);
 281 }
 282
 283 /* Likewise, but remove the registers.  */
 284
 285 static inline void
 286 remove_from_hard_reg_set (HARD_REG_SET *regs, machine_mode mode,
 287                           unsigned int regno)
 288 {
 289   unsigned int end_regno;
 290
 291   end_regno = end_hard_regno (mode, regno);
 292   do
 293     CLEAR_HARD_REG_BIT (*regs, regno);
 294   while (++regno < end_regno);
 295 }
 296
 297 /* Return true if REGS contains the whole of (reg:MODE REGNO).  */
 298
 299 static inline bool
 300 in_hard_reg_set_p (const HARD_REG_SET regs, machine_mode mode,
 301                    unsigned int regno)
 302 {
 303   unsigned int end_regno;
 304
 305   gcc_assert (HARD_REGISTER_NUM_P (regno));
 306
 307   if (!TEST_HARD_REG_BIT (regs, regno))
 308     return false;
 309
 310   end_regno = end_hard_regno (mode, regno);
 311
 312   if (!HARD_REGISTER_NUM_P (end_regno - 1))
 313     return false;
 314
 315   while (++regno < end_regno)
 316     if (!TEST_HARD_REG_BIT (regs, regno))
 317       return false;
 318
 319   return true;
 320 }
 321
 322 /* Return true if (reg:MODE REGNO) includes an element of REGS.  */
 323
 324 static inline bool
 325 overlaps_hard_reg_set_p (const HARD_REG_SET regs, machine_mode mode,
 326                          unsigned int regno)
 327 {
 328   unsigned int end_regno;
 329
 330   if (TEST_HARD_REG_BIT (regs, regno))
 331     return true;
 332
 333   end_regno = end_hard_regno (mode, regno);
 334   while (++regno < end_regno)
 335     if (TEST_HARD_REG_BIT (regs, regno))
 336       return true;
 337
 338   return false;
 339 }
 340
 341 /* Like add_to_hard_reg_set, but use a REGNO/NREGS range instead of
 342    REGNO and MODE.  */
 343
 344 static inline void
 345 add_range_to_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 346                            int nregs)
 347 {
 348   while (nregs-- > 0)
 349     SET_HARD_REG_BIT (*regs, regno + nregs);
 350 }
 351
 352 /* Likewise, but remove the registers.  */
 353
 354 static inline void
 355 remove_range_from_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 356                                 int nregs)
 357 {
 358   while (nregs-- > 0)
 359     CLEAR_HARD_REG_BIT (*regs, regno + nregs);
 360 }
 361
 362 /* Like overlaps_hard_reg_set_p, but use a REGNO/NREGS range instead of
 363    REGNO and MODE.  */
 364 static inline bool
 365 range_overlaps_hard_reg_set_p (const HARD_REG_SET set, unsigned regno,
 366                                int nregs)
 367 {
 368   while (nregs-- > 0)
 369     if (TEST_HARD_REG_BIT (set, regno + nregs))
 370       return true;
 371   return false;
 372 }
 373
 374 /* Like in_hard_reg_set_p, but use a REGNO/NREGS range instead of
 375    REGNO and MODE.  */
 376 static inline bool
 377 range_in_hard_reg_set_p (const HARD_REG_SET set, unsigned regno, int nregs)
 378 {
 379   while (nregs-- > 0)
 380     if (!TEST_HARD_REG_BIT (set, regno + nregs))
 381       return false;
 382   return true;
 383 }
 384
 385 /* Get registers used by given function call instruction.  */
 386 extern bool get_call_reg_set_usage (rtx_insn *insn, HARD_REG_SET *reg_set,
 387                                     HARD_REG_SET default_set);
 388
 389 #endif /* GCC_REGS_H */