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
  28 #define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
  29
  30 /* When you only have the mode of a pseudo register before it has a hard
  31    register chosen for it, this reports the size of each hard register
  32    a pseudo in such a mode would get allocated to.  A target may
  33    override this.  */
  34
  35 #ifndef REGMODE_NATURAL_SIZE
  36 #define REGMODE_NATURAL_SIZE(MODE)      UNITS_PER_WORD
  37 #endif
  38
  39 /* Maximum register number used in this function, plus one.  */
  40
  41 extern int max_regno;
  42
  43 /* REG_N_REFS and REG_N_SETS are initialized by a call to
  44    regstat_init_n_sets_and_refs from the current values of
  45    DF_REG_DEF_COUNT and DF_REG_USE_COUNT.  REG_N_REFS and REG_N_SETS
  46    should only be used if a pass need to change these values in some
  47    magical way or or the pass needs to have accurate values for these
  48    and is not using incremental df scanning.
  49
  50    At the end of a pass that uses REG_N_REFS and REG_N_SETS, a call
  51    should be made to regstat_free_n_sets_and_refs.
  52
  53    Local alloc seems to play pretty loose with these values.
  54    REG_N_REFS is set to 0 if the register is used in an asm.
  55    Furthermore, local_alloc calls regclass to hack both REG_N_REFS and
  56    REG_N_SETS for three address insns.  Other passes seem to have
  57    other special values.  */
  58
  59
  60
  61 /* Structure to hold values for REG_N_SETS (i) and REG_N_REFS (i). */
  62
  63 struct regstat_n_sets_and_refs_t
  64 {
  65   int sets;                     /* # of times (REG n) is set */
  66   int refs;                     /* # of times (REG n) is used or set */
  67 };
  68
  69 extern struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs;
  70
  71 /* Indexed by n, gives number of times (REG n) is used or set.  */
  72 static inline int
  73 REG_N_REFS(int regno)
  74 {
  75   return regstat_n_sets_and_refs[regno].refs;
  76 }
  77
  78 /* Indexed by n, gives number of times (REG n) is used or set.  */
  79 #define SET_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs = V)
  80 #define INC_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs += V)
  81
  82 /* Indexed by n, gives number of times (REG n) is set.  */
  83 static inline int
  84 REG_N_SETS (int regno)
  85 {
  86   return regstat_n_sets_and_refs[regno].sets;
  87 }
  88
  89 /* Indexed by n, gives number of times (REG n) is set.  */
  90 #define SET_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets = V)
  91 #define INC_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets += V)
  92
  93
  94 /* Functions defined in reg-stat.c.  */
  95 extern void regstat_init_n_sets_and_refs (void);
  96 extern void regstat_free_n_sets_and_refs (void);
  97 extern void regstat_compute_ri (void);
  98 extern void regstat_free_ri (void);
  99 extern bitmap regstat_get_setjmp_crosses (void);
 100 extern void regstat_compute_calls_crossed (void);
 101 extern void regstat_free_calls_crossed (void);
 102
 103
 104 /* Register information indexed by register number.  This structure is
 105    initialized by calling regstat_compute_ri and is destroyed by
 106    calling regstat_free_ri.  */
 107 struct reg_info_t
 108 {
 109   int freq;                     /* # estimated frequency (REG n) is used or set */
 110   int deaths;                   /* # of times (REG n) dies */
 111   int live_length;              /* # of instructions (REG n) is live */
 112   int calls_crossed;            /* # of calls (REG n) is live across */
 113   int freq_calls_crossed;       /* # estimated frequency (REG n) crosses call */
 114   int throw_calls_crossed;      /* # of calls that may throw (REG n) is live across */
 115   int basic_block;              /* # of basic blocks (REG n) is used in */
 116 };
 117
 118 extern struct reg_info_t *reg_info_p;
 119
 120 /* The number allocated elements of reg_info_p.  */
 121 extern size_t reg_info_p_size;
 122
 123 /* Estimate frequency of references to register N.  */
 124
 125 #define REG_FREQ(N) (reg_info_p[N].freq)
 126
 127 /* The weights for each insn varies from 0 to REG_FREQ_BASE.
 128    This constant does not need to be high, as in infrequently executed
 129    regions we want to count instructions equivalently to optimize for
 130    size instead of speed.  */
 131 #define REG_FREQ_MAX 1000
 132
 133 /* Compute register frequency from the BB frequency.  When optimizing for size,
 134    or profile driven feedback is available and the function is never executed,
 135    frequency is always equivalent.  Otherwise rescale the basic block
 136    frequency.  */
 137 #define REG_FREQ_FROM_BB(bb) (optimize_size                                   \
 138                               || (flag_branch_probabilities                   \
 139                                   && !ENTRY_BLOCK_PTR->count)                 \
 140                               ? REG_FREQ_MAX                                  \
 141                               : ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
 142                               ? ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
 143                               : 1)
 144
 145 /* Indexed by N, gives number of insns in which register N dies.
 146    Note that if register N is live around loops, it can die
 147    in transitions between basic blocks, and that is not counted here.
 148    So this is only a reliable indicator of how many regions of life there are
 149    for registers that are contained in one basic block.  */
 150
 151 #define REG_N_DEATHS(N) (reg_info_p[N].deaths)
 152
 153 /* Get the number of consecutive words required to hold pseudo-reg N.  */
 154
 155 #define PSEUDO_REGNO_SIZE(N) \
 156   ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1)         \
 157    / UNITS_PER_WORD)
 158
 159 /* Get the number of bytes required to hold pseudo-reg N.  */
 160
 161 #define PSEUDO_REGNO_BYTES(N) \
 162   GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
 163
 164 /* Get the machine mode of pseudo-reg N.  */
 165
 166 #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
 167
 168 /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live.  */
 169
 170 #define REG_N_CALLS_CROSSED(N)  (reg_info_p[N].calls_crossed)
 171 #define REG_FREQ_CALLS_CROSSED(N)  (reg_info_p[N].freq_calls_crossed)
 172
 173 /* Indexed by N, gives number of CALL_INSNS that may throw, across which
 174    (REG n) is live.  */
 175
 176 #define REG_N_THROWING_CALLS_CROSSED(N) (reg_info_p[N].throw_calls_crossed)
 177
 178 /* Total number of instructions at which (REG n) is live.  The larger
 179    this is, the less priority (REG n) gets for allocation in a hard
 180    register (in global-alloc).  This is set in df-problems.c whenever
 181    register info is requested and remains valid for the rest of the
 182    compilation of the function; it is used to control register
 183    allocation.
 184
 185    local-alloc.c may alter this number to change the priority.
 186
 187    Negative values are special.
 188    -1 is used to mark a pseudo reg which has a constant or memory equivalent
 189    and is used infrequently enough that it should not get a hard register.
 190    -2 is used to mark a pseudo reg for a parameter, when a frame pointer
 191    is not required.  global.c makes an allocno for this but does
 192    not try to assign a hard register to it.  */
 193
 194 #define REG_LIVE_LENGTH(N)  (reg_info_p[N].live_length)
 195
 196 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 197    If the value is REG_BLOCK_GLOBAL (-1),
 198    it means (REG n) is used in more than one basic block.
 199    REG_BLOCK_UNKNOWN (0) means it hasn't been seen yet so we don't know.
 200    This information remains valid for the rest of the compilation
 201    of the current function; it is used to control register allocation.  */
 202
 203 #define REG_BLOCK_UNKNOWN 0
 204 #define REG_BLOCK_GLOBAL -1
 205
 206 #define REG_BASIC_BLOCK(N) (reg_info_p[N].basic_block)
 207
 208 /* Vector of substitutions of register numbers,
 209    used to map pseudo regs into hardware regs.
 210
 211    This can't be folded into reg_n_info without changing all of the
 212    machine dependent directories, since the reload functions
 213    in the machine dependent files access it.  */
 214
 215 extern short *reg_renumber;
 216
 217 /* Flag set by local-alloc or global-alloc if they decide to allocate
 218    something in a call-clobbered register.  */
 219
 220 extern int caller_save_needed;
 221
 222 /* Predicate to decide whether to give a hard reg to a pseudo which
 223    is referenced REFS times and would need to be saved and restored
 224    around a call CALLS times.  */
 225
 226 #ifndef CALLER_SAVE_PROFITABLE
 227 #define CALLER_SAVE_PROFITABLE(REFS, CALLS)  (4 * (CALLS) < (REFS))
 228 #endif
 229
 230 /* Select a register mode required for caller save of hard regno REGNO.  */
 231 #ifndef HARD_REGNO_CALLER_SAVE_MODE
 232 #define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \
 233   choose_hard_reg_mode (REGNO, NREGS, false)
 234 #endif
 235
 236 /* Registers that get partially clobbered by a call in a given mode.
 237    These must not be call used registers.  */
 238 #ifndef HARD_REGNO_CALL_PART_CLOBBERED
 239 #define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0
 240 #endif
 241
 242 typedef unsigned short move_table[N_REG_CLASSES];
 243
 244 /* Target-dependent globals.  */
 245 struct target_regs {
 246   /* For each starting hard register, the number of consecutive hard
 247      registers that a given machine mode occupies.  */
 248   unsigned char x_hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
 249
 250   /* For each hard register, the widest mode object that it can contain.
 251      This will be a MODE_INT mode if the register can hold integers.  Otherwise
 252      it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
 253      register.  */
 254   enum machine_mode x_reg_raw_mode[FIRST_PSEUDO_REGISTER];
 255
 256   /* Vector indexed by machine mode saying whether there are regs of
 257      that mode.  */
 258   bool x_have_regs_of_mode[MAX_MACHINE_MODE];
 259
 260   /* 1 if the corresponding class contains a register of the given mode.  */
 261   char x_contains_reg_of_mode[N_REG_CLASSES][MAX_MACHINE_MODE];
 262
 263   /* Maximum cost of moving from a register in one class to a register
 264      in another class.  Based on TARGET_REGISTER_MOVE_COST.  */
 265   move_table *x_move_cost[MAX_MACHINE_MODE];
 266
 267   /* Similar, but here we don't have to move if the first index is a
 268      subset of the second so in that case the cost is zero.  */
 269   move_table *x_may_move_in_cost[MAX_MACHINE_MODE];
 270
 271   /* Similar, but here we don't have to move if the first index is a
 272      superset of the second so in that case the cost is zero.  */
 273   move_table *x_may_move_out_cost[MAX_MACHINE_MODE];
 274
 275   /* Keep track of the last mode we initialized move costs for.  */
 276   int x_last_mode_for_init_move_cost;
 277
 278   /* Record for each mode whether we can move a register directly to or
 279      from an object of that mode in memory.  If we can't, we won't try
 280      to use that mode directly when accessing a field of that mode.  */
 281   char x_direct_load[NUM_MACHINE_MODES];
 282   char x_direct_store[NUM_MACHINE_MODES];
 283
 284   /* Record for each mode whether we can float-extend from memory.  */
 285   bool x_float_extend_from_mem[NUM_MACHINE_MODES][NUM_MACHINE_MODES];
 286 };
 287
 288 extern struct target_regs default_target_regs;
 289 #if SWITCHABLE_TARGET
 290 extern struct target_regs *this_target_regs;
 291 #else
 292 #define this_target_regs (&default_target_regs)
 293 #endif
 294
 295 #define hard_regno_nregs \
 296   (this_target_regs->x_hard_regno_nregs)
 297 #define reg_raw_mode \
 298   (this_target_regs->x_reg_raw_mode)
 299 #define have_regs_of_mode \
 300   (this_target_regs->x_have_regs_of_mode)
 301 #define contains_reg_of_mode \
 302   (this_target_regs->x_contains_reg_of_mode)
 303 #define move_cost \
 304   (this_target_regs->x_move_cost)
 305 #define may_move_in_cost \
 306   (this_target_regs->x_may_move_in_cost)
 307 #define may_move_out_cost \
 308   (this_target_regs->x_may_move_out_cost)
 309 #define direct_load \
 310   (this_target_regs->x_direct_load)
 311 #define direct_store \
 312   (this_target_regs->x_direct_store)
 313 #define float_extend_from_mem \
 314   (this_target_regs->x_float_extend_from_mem)
 315
 316 /* Return an exclusive upper bound on the registers occupied by hard
 317    register (reg:MODE REGNO).  */
 318
 319 static inline unsigned int
 320 end_hard_regno (enum machine_mode mode, unsigned int regno)
 321 {
 322   return regno + hard_regno_nregs[regno][(int) mode];
 323 }
 324
 325 /* Likewise for hard register X.  */
 326
 327 #define END_HARD_REGNO(X) end_hard_regno (GET_MODE (X), REGNO (X))
 328
 329 /* Likewise for hard or pseudo register X.  */
 330
 331 #define END_REGNO(X) (HARD_REGISTER_P (X) ? END_HARD_REGNO (X) : REGNO (X) + 1)
 332
 333 /* Add to REGS all the registers required to store a value of mode MODE
 334    in register REGNO.  */
 335
 336 static inline void
 337 add_to_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
 338                      unsigned int regno)
 339 {
 340   unsigned int end_regno;
 341
 342   end_regno = end_hard_regno (mode, regno);
 343   do
 344     SET_HARD_REG_BIT (*regs, regno);
 345   while (++regno < end_regno);
 346 }
 347
 348 /* Likewise, but remove the registers.  */
 349
 350 static inline void
 351 remove_from_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
 352                           unsigned int regno)
 353 {
 354   unsigned int end_regno;
 355
 356   end_regno = end_hard_regno (mode, regno);
 357   do
 358     CLEAR_HARD_REG_BIT (*regs, regno);
 359   while (++regno < end_regno);
 360 }
 361
 362 /* Return true if REGS contains the whole of (reg:MODE REGNO).  */
 363
 364 static inline bool
 365 in_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
 366                    unsigned int regno)
 367 {
 368   unsigned int end_regno;
 369
 370   if (!TEST_HARD_REG_BIT (regs, regno))
 371     return false;
 372
 373   end_regno = end_hard_regno (mode, regno);
 374   while (++regno < end_regno)
 375     if (!TEST_HARD_REG_BIT (regs, regno))
 376       return false;
 377
 378   return true;
 379 }
 380
 381 /* Return true if (reg:MODE REGNO) includes an element of REGS.  */
 382
 383 static inline bool
 384 overlaps_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
 385                          unsigned int regno)
 386 {
 387   unsigned int end_regno;
 388
 389   if (TEST_HARD_REG_BIT (regs, regno))
 390     return true;
 391
 392   end_regno = end_hard_regno (mode, regno);
 393   while (++regno < end_regno)
 394     if (TEST_HARD_REG_BIT (regs, regno))
 395       return true;
 396
 397   return false;
 398 }
 399
 400 #endif /* GCC_REGS_H */