gcc/regs.h

   1 /* Define per-register tables for data flow info and register allocation.
   2    Copyright (C) 1987-2016 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 live_length;              /* # of instructions (REG n) is live */
 109   int calls_crossed;            /* # of calls (REG n) is live across */
 110   int freq_calls_crossed;       /* # estimated frequency (REG n) crosses call */
 111   int throw_calls_crossed;      /* # of calls that may throw (REG n) is live across */
 112   int basic_block;              /* # of basic blocks (REG n) is used in */
 113 };
 114
 115 extern struct reg_info_t *reg_info_p;
 116
 117 /* The number allocated elements of reg_info_p.  */
 118 extern size_t reg_info_p_size;
 119
 120 /* Estimate frequency of references to register N.  */
 121
 122 #define REG_FREQ(N) (reg_info_p[N].freq)
 123
 124 /* The weights for each insn varies from 0 to REG_FREQ_BASE.
 125    This constant does not need to be high, as in infrequently executed
 126    regions we want to count instructions equivalently to optimize for
 127    size instead of speed.  */
 128 #define REG_FREQ_MAX 1000
 129
 130 /* Compute register frequency from the BB frequency.  When optimizing for size,
 131    or profile driven feedback is available and the function is never executed,
 132    frequency is always equivalent.  Otherwise rescale the basic block
 133    frequency.  */
 134 #define REG_FREQ_FROM_BB(bb) (optimize_function_for_size_p (cfun)             \
 135                               ? REG_FREQ_MAX                                  \
 136                               : ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
 137                               ? ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
 138                               : 1)
 139
 140 /* Indexed by N, gives number of insns in which register N dies.
 141    Note that if register N is live around loops, it can die
 142    in transitions between basic blocks, and that is not counted here.
 143    So this is only a reliable indicator of how many regions of life there are
 144    for registers that are contained in one basic block.  */
 145
 146 #define REG_N_DEATHS(N) (reg_info_p[N].deaths)
 147
 148 /* Get the number of consecutive words required to hold pseudo-reg N.  */
 149
 150 #define PSEUDO_REGNO_SIZE(N) \
 151   ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1)         \
 152    / UNITS_PER_WORD)
 153
 154 /* Get the number of bytes required to hold pseudo-reg N.  */
 155
 156 #define PSEUDO_REGNO_BYTES(N) \
 157   GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
 158
 159 /* Get the machine mode of pseudo-reg N.  */
 160
 161 #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
 162
 163 /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live.  */
 164
 165 #define REG_N_CALLS_CROSSED(N)  (reg_info_p[N].calls_crossed)
 166 #define REG_FREQ_CALLS_CROSSED(N)  (reg_info_p[N].freq_calls_crossed)
 167
 168 /* Indexed by N, gives number of CALL_INSNS that may throw, across which
 169    (REG n) is live.  */
 170
 171 #define REG_N_THROWING_CALLS_CROSSED(N) (reg_info_p[N].throw_calls_crossed)
 172
 173 /* Total number of instructions at which (REG n) is live.
 174
 175    This is set in regstat.c whenever register info is requested and
 176    remains valid for the rest of the compilation of the function; it is
 177    used to control register allocation.  The larger this is, the less
 178    priority (REG n) gets for allocation in a hard register (in IRA in
 179    priority-coloring mode).
 180
 181    Negative values are special: -1 is used to mark a pseudo reg that
 182    should not be allocated to a hard register, because it crosses a
 183    setjmp call.  */
 184
 185 #define REG_LIVE_LENGTH(N)  (reg_info_p[N].live_length)
 186
 187 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 188    If the value is REG_BLOCK_GLOBAL (-1),
 189    it means (REG n) is used in more than one basic block.
 190    REG_BLOCK_UNKNOWN (0) means it hasn't been seen yet so we don't know.
 191    This information remains valid for the rest of the compilation
 192    of the current function; it is used to control register allocation.  */
 193
 194 #define REG_BLOCK_UNKNOWN 0
 195 #define REG_BLOCK_GLOBAL -1
 196
 197 #define REG_BASIC_BLOCK(N) (reg_info_p[N].basic_block)
 198
 199 /* Vector of substitutions of register numbers,
 200    used to map pseudo regs into hardware regs.
 201
 202    This can't be folded into reg_n_info without changing all of the
 203    machine dependent directories, since the reload functions
 204    in the machine dependent files access it.  */
 205
 206 extern short *reg_renumber;
 207
 208 /* Flag set by local-alloc or global-alloc if they decide to allocate
 209    something in a call-clobbered register.  */
 210
 211 extern int caller_save_needed;
 212
 213 /* Select a register mode required for caller save of hard regno REGNO.  */
 214 #ifndef HARD_REGNO_CALLER_SAVE_MODE
 215 #define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \
 216   choose_hard_reg_mode (REGNO, NREGS, false)
 217 #endif
 218
 219 /* Registers that get partially clobbered by a call in a given mode.
 220    These must not be call used registers.  */
 221 #ifndef HARD_REGNO_CALL_PART_CLOBBERED
 222 #define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0
 223 #endif
 224
 225 /* Target-dependent globals.  */
 226 struct target_regs {
 227   /* For each starting hard register, the number of consecutive hard
 228      registers that a given machine mode occupies.  */
 229   unsigned char x_hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
 230
 231   /* For each hard register, the widest mode object that it can contain.
 232      This will be a MODE_INT mode if the register can hold integers.  Otherwise
 233      it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
 234      register.  */
 235   machine_mode x_reg_raw_mode[FIRST_PSEUDO_REGISTER];
 236
 237   /* Vector indexed by machine mode saying whether there are regs of
 238      that mode.  */
 239   bool x_have_regs_of_mode[MAX_MACHINE_MODE];
 240
 241   /* 1 if the corresponding class contains a register of the given mode.  */
 242   char x_contains_reg_of_mode[N_REG_CLASSES][MAX_MACHINE_MODE];
 243
 244   /* Record for each mode whether we can move a register directly to or
 245      from an object of that mode in memory.  If we can't, we won't try
 246      to use that mode directly when accessing a field of that mode.  */
 247   char x_direct_load[NUM_MACHINE_MODES];
 248   char x_direct_store[NUM_MACHINE_MODES];
 249
 250   /* Record for each mode whether we can float-extend from memory.  */
 251   bool x_float_extend_from_mem[NUM_MACHINE_MODES][NUM_MACHINE_MODES];
 252 };
 253
 254 extern struct target_regs default_target_regs;
 255 #if SWITCHABLE_TARGET
 256 extern struct target_regs *this_target_regs;
 257 #else
 258 #define this_target_regs (&default_target_regs)
 259 #endif
 260
 261 #define hard_regno_nregs \
 262   (this_target_regs->x_hard_regno_nregs)
 263 #define reg_raw_mode \
 264   (this_target_regs->x_reg_raw_mode)
 265 #define have_regs_of_mode \
 266   (this_target_regs->x_have_regs_of_mode)
 267 #define contains_reg_of_mode \
 268   (this_target_regs->x_contains_reg_of_mode)
 269 #define direct_load \
 270   (this_target_regs->x_direct_load)
 271 #define direct_store \
 272   (this_target_regs->x_direct_store)
 273 #define float_extend_from_mem \
 274   (this_target_regs->x_float_extend_from_mem)
 275
 276 /* Return an exclusive upper bound on the registers occupied by hard
 277    register (reg:MODE REGNO).  */
 278
 279 static inline unsigned int
 280 end_hard_regno (machine_mode mode, unsigned int regno)
 281 {
 282   return regno + hard_regno_nregs[regno][(int) mode];
 283 }
 284
 285 /* Add to REGS all the registers required to store a value of mode MODE
 286    in register REGNO.  */
 287
 288 static inline void
 289 add_to_hard_reg_set (HARD_REG_SET *regs, machine_mode mode,
 290                      unsigned int regno)
 291 {
 292   unsigned int end_regno;
 293
 294   end_regno = end_hard_regno (mode, regno);
 295   do
 296     SET_HARD_REG_BIT (*regs, regno);
 297   while (++regno < end_regno);
 298 }
 299
 300 /* Likewise, but remove the registers.  */
 301
 302 static inline void
 303 remove_from_hard_reg_set (HARD_REG_SET *regs, machine_mode mode,
 304                           unsigned int regno)
 305 {
 306   unsigned int end_regno;
 307
 308   end_regno = end_hard_regno (mode, regno);
 309   do
 310     CLEAR_HARD_REG_BIT (*regs, regno);
 311   while (++regno < end_regno);
 312 }
 313
 314 /* Return true if REGS contains the whole of (reg:MODE REGNO).  */
 315
 316 static inline bool
 317 in_hard_reg_set_p (const HARD_REG_SET regs, machine_mode mode,
 318                    unsigned int regno)
 319 {
 320   unsigned int end_regno;
 321
 322   gcc_assert (HARD_REGISTER_NUM_P (regno));
 323
 324   if (!TEST_HARD_REG_BIT (regs, regno))
 325     return false;
 326
 327   end_regno = end_hard_regno (mode, regno);
 328
 329   if (!HARD_REGISTER_NUM_P (end_regno - 1))
 330     return false;
 331
 332   while (++regno < end_regno)
 333     if (!TEST_HARD_REG_BIT (regs, regno))
 334       return false;
 335
 336   return true;
 337 }
 338
 339 /* Return true if (reg:MODE REGNO) includes an element of REGS.  */
 340
 341 static inline bool
 342 overlaps_hard_reg_set_p (const HARD_REG_SET regs, machine_mode mode,
 343                          unsigned int regno)
 344 {
 345   unsigned int end_regno;
 346
 347   if (TEST_HARD_REG_BIT (regs, regno))
 348     return true;
 349
 350   end_regno = end_hard_regno (mode, regno);
 351   while (++regno < end_regno)
 352     if (TEST_HARD_REG_BIT (regs, regno))
 353       return true;
 354
 355   return false;
 356 }
 357
 358 /* Like add_to_hard_reg_set, but use a REGNO/NREGS range instead of
 359    REGNO and MODE.  */
 360
 361 static inline void
 362 add_range_to_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 363                            int nregs)
 364 {
 365   while (nregs-- > 0)
 366     SET_HARD_REG_BIT (*regs, regno + nregs);
 367 }
 368
 369 /* Likewise, but remove the registers.  */
 370
 371 static inline void
 372 remove_range_from_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 373                                 int nregs)
 374 {
 375   while (nregs-- > 0)
 376     CLEAR_HARD_REG_BIT (*regs, regno + nregs);
 377 }
 378
 379 /* Like overlaps_hard_reg_set_p, but use a REGNO/NREGS range instead of
 380    REGNO and MODE.  */
 381 static inline bool
 382 range_overlaps_hard_reg_set_p (const HARD_REG_SET set, unsigned regno,
 383                                int nregs)
 384 {
 385   while (nregs-- > 0)
 386     if (TEST_HARD_REG_BIT (set, regno + nregs))
 387       return true;
 388   return false;
 389 }
 390
 391 /* Like in_hard_reg_set_p, but use a REGNO/NREGS range instead of
 392    REGNO and MODE.  */
 393 static inline bool
 394 range_in_hard_reg_set_p (const HARD_REG_SET set, unsigned regno, int nregs)
 395 {
 396   while (nregs-- > 0)
 397     if (!TEST_HARD_REG_BIT (set, regno + nregs))
 398       return false;
 399   return true;
 400 }
 401
 402 /* Get registers used by given function call instruction.  */
 403 extern bool get_call_reg_set_usage (rtx_insn *insn, HARD_REG_SET *reg_set,
 404                                     HARD_REG_SET default_set);
 405
 406 #endif /* GCC_REGS_H */