gcc/regs.h

   1 /* Define per-register tables for data flow info and register allocation.
   2    Copyright (C) 1987-2014 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 #include "machmode.h"
  24 #include "hard-reg-set.h"
  25 #include "rtl.h"
  26
  27 #define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
  28
  29 /* When you only have the mode of a pseudo register before it has a hard
  30    register chosen for it, this reports the size of each hard register
  31    a pseudo in such a mode would get allocated to.  A target may
  32    override this.  */
  33
  34 #ifndef REGMODE_NATURAL_SIZE
  35 #define REGMODE_NATURAL_SIZE(MODE)      UNITS_PER_WORD
  36 #endif
  37
  38 /* Maximum register number used in this function, plus one.  */
  39
  40 extern int max_regno;
  41
  42 /* REG_N_REFS and REG_N_SETS are initialized by a call to
  43    regstat_init_n_sets_and_refs from the current values of
  44    DF_REG_DEF_COUNT and DF_REG_USE_COUNT.  REG_N_REFS and REG_N_SETS
  45    should only be used if a pass need to change these values in some
  46    magical way or the pass needs to have accurate values for these
  47    and is not using incremental df scanning.
  48
  49    At the end of a pass that uses REG_N_REFS and REG_N_SETS, a call
  50    should be made to regstat_free_n_sets_and_refs.
  51
  52    Local alloc seems to play pretty loose with these values.
  53    REG_N_REFS is set to 0 if the register is used in an asm.
  54    Furthermore, local_alloc calls regclass to hack both REG_N_REFS and
  55    REG_N_SETS for three address insns.  Other passes seem to have
  56    other special values.  */
  57
  58
  59
  60 /* Structure to hold values for REG_N_SETS (i) and REG_N_REFS (i). */
  61
  62 struct regstat_n_sets_and_refs_t
  63 {
  64   int sets;                     /* # of times (REG n) is set */
  65   int refs;                     /* # of times (REG n) is used or set */
  66 };
  67
  68 extern struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs;
  69
  70 /* Indexed by n, gives number of times (REG n) is used or set.  */
  71 static inline int
  72 REG_N_REFS (int regno)
  73 {
  74   return regstat_n_sets_and_refs[regno].refs;
  75 }
  76
  77 /* Indexed by n, gives number of times (REG n) is used or set.  */
  78 #define SET_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs = V)
  79 #define INC_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs += V)
  80
  81 /* Indexed by n, gives number of times (REG n) is set.  */
  82 static inline int
  83 REG_N_SETS (int regno)
  84 {
  85   return regstat_n_sets_and_refs[regno].sets;
  86 }
  87
  88 /* Indexed by n, gives number of times (REG n) is set.  */
  89 #define SET_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets = V)
  90 #define INC_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets += V)
  91
  92 /* Given a REG, return TRUE if the reg is a PARM_DECL, FALSE otherwise.  */
  93 extern bool reg_is_parm_p (rtx);
  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_function_for_size_p (cfun)             \
 139                               ? REG_FREQ_MAX                                  \
 140                               : ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
 141                               ? ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
 142                               : 1)
 143
 144 /* Indexed by N, gives number of insns in which register N dies.
 145    Note that if register N is live around loops, it can die
 146    in transitions between basic blocks, and that is not counted here.
 147    So this is only a reliable indicator of how many regions of life there are
 148    for registers that are contained in one basic block.  */
 149
 150 #define REG_N_DEATHS(N) (reg_info_p[N].deaths)
 151
 152 /* Get the number of consecutive words required to hold pseudo-reg N.  */
 153
 154 #define PSEUDO_REGNO_SIZE(N) \
 155   ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1)         \
 156    / UNITS_PER_WORD)
 157
 158 /* Get the number of bytes required to hold pseudo-reg N.  */
 159
 160 #define PSEUDO_REGNO_BYTES(N) \
 161   GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
 162
 163 /* Get the machine mode of pseudo-reg N.  */
 164
 165 #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
 166
 167 /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live.  */
 168
 169 #define REG_N_CALLS_CROSSED(N)  (reg_info_p[N].calls_crossed)
 170 #define REG_FREQ_CALLS_CROSSED(N)  (reg_info_p[N].freq_calls_crossed)
 171
 172 /* Indexed by N, gives number of CALL_INSNS that may throw, across which
 173    (REG n) is live.  */
 174
 175 #define REG_N_THROWING_CALLS_CROSSED(N) (reg_info_p[N].throw_calls_crossed)
 176
 177 /* Total number of instructions at which (REG n) is live.
 178
 179    This is set in regstat.c whenever register info is requested and
 180    remains valid for the rest of the compilation of the function; it is
 181    used to control register allocation.  The larger this is, the less
 182    priority (REG n) gets for allocation in a hard register (in IRA in
 183    priority-coloring mode).
 184
 185    Negative values are special: -1 is used to mark a pseudo reg that
 186    should not be allocated to a hard register, because it crosses a
 187    setjmp call.  */
 188
 189 #define REG_LIVE_LENGTH(N)  (reg_info_p[N].live_length)
 190
 191 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 192    If the value is REG_BLOCK_GLOBAL (-1),
 193    it means (REG n) is used in more than one basic block.
 194    REG_BLOCK_UNKNOWN (0) means it hasn't been seen yet so we don't know.
 195    This information remains valid for the rest of the compilation
 196    of the current function; it is used to control register allocation.  */
 197
 198 #define REG_BLOCK_UNKNOWN 0
 199 #define REG_BLOCK_GLOBAL -1
 200
 201 #define REG_BASIC_BLOCK(N) (reg_info_p[N].basic_block)
 202
 203 /* Vector of substitutions of register numbers,
 204    used to map pseudo regs into hardware regs.
 205
 206    This can't be folded into reg_n_info without changing all of the
 207    machine dependent directories, since the reload functions
 208    in the machine dependent files access it.  */
 209
 210 extern short *reg_renumber;
 211
 212 /* Flag set by local-alloc or global-alloc if they decide to allocate
 213    something in a call-clobbered register.  */
 214
 215 extern int caller_save_needed;
 216
 217 /* Select a register mode required for caller save of hard regno REGNO.  */
 218 #ifndef HARD_REGNO_CALLER_SAVE_MODE
 219 #define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \
 220   choose_hard_reg_mode (REGNO, NREGS, false)
 221 #endif
 222
 223 /* Registers that get partially clobbered by a call in a given mode.
 224    These must not be call used registers.  */
 225 #ifndef HARD_REGNO_CALL_PART_CLOBBERED
 226 #define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0
 227 #endif
 228
 229 /* Target-dependent globals.  */
 230 struct target_regs {
 231   /* For each starting hard register, the number of consecutive hard
 232      registers that a given machine mode occupies.  */
 233   unsigned char x_hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
 234
 235   /* For each hard register, the widest mode object that it can contain.
 236      This will be a MODE_INT mode if the register can hold integers.  Otherwise
 237      it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
 238      register.  */
 239   enum machine_mode x_reg_raw_mode[FIRST_PSEUDO_REGISTER];
 240
 241   /* Vector indexed by machine mode saying whether there are regs of
 242      that mode.  */
 243   bool x_have_regs_of_mode[MAX_MACHINE_MODE];
 244
 245   /* 1 if the corresponding class contains a register of the given mode.  */
 246   char x_contains_reg_of_mode[N_REG_CLASSES][MAX_MACHINE_MODE];
 247
 248   /* Record for each mode whether we can move a register directly to or
 249      from an object of that mode in memory.  If we can't, we won't try
 250      to use that mode directly when accessing a field of that mode.  */
 251   char x_direct_load[NUM_MACHINE_MODES];
 252   char x_direct_store[NUM_MACHINE_MODES];
 253
 254   /* Record for each mode whether we can float-extend from memory.  */
 255   bool x_float_extend_from_mem[NUM_MACHINE_MODES][NUM_MACHINE_MODES];
 256 };
 257
 258 extern struct target_regs default_target_regs;
 259 #if SWITCHABLE_TARGET
 260 extern struct target_regs *this_target_regs;
 261 #else
 262 #define this_target_regs (&default_target_regs)
 263 #endif
 264
 265 #define hard_regno_nregs \
 266   (this_target_regs->x_hard_regno_nregs)
 267 #define reg_raw_mode \
 268   (this_target_regs->x_reg_raw_mode)
 269 #define have_regs_of_mode \
 270   (this_target_regs->x_have_regs_of_mode)
 271 #define contains_reg_of_mode \
 272   (this_target_regs->x_contains_reg_of_mode)
 273 #define direct_load \
 274   (this_target_regs->x_direct_load)
 275 #define direct_store \
 276   (this_target_regs->x_direct_store)
 277 #define float_extend_from_mem \
 278   (this_target_regs->x_float_extend_from_mem)
 279
 280 /* Return an exclusive upper bound on the registers occupied by hard
 281    register (reg:MODE REGNO).  */
 282
 283 static inline unsigned int
 284 end_hard_regno (enum machine_mode mode, unsigned int regno)
 285 {
 286   return regno + hard_regno_nregs[regno][(int) mode];
 287 }
 288
 289 /* Likewise for hard register X.  */
 290
 291 #define END_HARD_REGNO(X) end_hard_regno (GET_MODE (X), REGNO (X))
 292
 293 /* Likewise for hard or pseudo register X.  */
 294
 295 #define END_REGNO(X) (HARD_REGISTER_P (X) ? END_HARD_REGNO (X) : REGNO (X) + 1)
 296
 297 /* Add to REGS all the registers required to store a value of mode MODE
 298    in register REGNO.  */
 299
 300 static inline void
 301 add_to_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
 302                      unsigned int regno)
 303 {
 304   unsigned int end_regno;
 305
 306   end_regno = end_hard_regno (mode, regno);
 307   do
 308     SET_HARD_REG_BIT (*regs, regno);
 309   while (++regno < end_regno);
 310 }
 311
 312 /* Likewise, but remove the registers.  */
 313
 314 static inline void
 315 remove_from_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     CLEAR_HARD_REG_BIT (*regs, regno);
 323   while (++regno < end_regno);
 324 }
 325
 326 /* Return true if REGS contains the whole of (reg:MODE REGNO).  */
 327
 328 static inline bool
 329 in_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
 330                    unsigned int regno)
 331 {
 332   unsigned int end_regno;
 333
 334   gcc_assert (HARD_REGISTER_NUM_P (regno));
 335
 336   if (!TEST_HARD_REG_BIT (regs, regno))
 337     return false;
 338
 339   end_regno = end_hard_regno (mode, regno);
 340
 341   if (!HARD_REGISTER_NUM_P (end_regno - 1))
 342     return false;
 343
 344   while (++regno < end_regno)
 345     if (!TEST_HARD_REG_BIT (regs, regno))
 346       return false;
 347
 348   return true;
 349 }
 350
 351 /* Return true if (reg:MODE REGNO) includes an element of REGS.  */
 352
 353 static inline bool
 354 overlaps_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
 355                          unsigned int regno)
 356 {
 357   unsigned int end_regno;
 358
 359   if (TEST_HARD_REG_BIT (regs, regno))
 360     return true;
 361
 362   end_regno = end_hard_regno (mode, regno);
 363   while (++regno < end_regno)
 364     if (TEST_HARD_REG_BIT (regs, regno))
 365       return true;
 366
 367   return false;
 368 }
 369
 370 /* Like add_to_hard_reg_set, but use a REGNO/NREGS range instead of
 371    REGNO and MODE.  */
 372
 373 static inline void
 374 add_range_to_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 375                            int nregs)
 376 {
 377   while (nregs-- > 0)
 378     SET_HARD_REG_BIT (*regs, regno + nregs);
 379 }
 380
 381 /* Likewise, but remove the registers.  */
 382
 383 static inline void
 384 remove_range_from_hard_reg_set (HARD_REG_SET *regs, unsigned int regno,
 385                                 int nregs)
 386 {
 387   while (nregs-- > 0)
 388     CLEAR_HARD_REG_BIT (*regs, regno + nregs);
 389 }
 390
 391 /* Like overlaps_hard_reg_set_p, but use a REGNO/NREGS range instead of
 392    REGNO and MODE.  */
 393 static inline bool
 394 range_overlaps_hard_reg_set_p (const HARD_REG_SET set, unsigned regno,
 395                                int nregs)
 396 {
 397   while (nregs-- > 0)
 398     if (TEST_HARD_REG_BIT (set, regno + nregs))
 399       return true;
 400   return false;
 401 }
 402
 403 /* Like in_hard_reg_set_p, but use a REGNO/NREGS range instead of
 404    REGNO and MODE.  */
 405 static inline bool
 406 range_in_hard_reg_set_p (const HARD_REG_SET set, unsigned regno, int nregs)
 407 {
 408   while (nregs-- > 0)
 409     if (!TEST_HARD_REG_BIT (set, regno + nregs))
 410       return false;
 411   return true;
 412 }
 413
 414 /* Get registers used by given function call instruction.  */
 415 extern bool get_call_reg_set_usage (rtx_insn *insn, HARD_REG_SET *reg_set,
 416                                     HARD_REG_SET default_set);
 417
 418 #endif /* GCC_REGS_H */