gcc/hard-reg-set.h

   1 /* Sets (bit vectors) of hard registers, and operations on them.
   2    Copyright (C) 1987-2021 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_HARD_REG_SET_H
  21 #define GCC_HARD_REG_SET_H
  22
  23 #include "array-traits.h"
  24
  25 /* Define the type of a set of hard registers.  */
  26
  27 /* HARD_REG_ELT_TYPE is a typedef of the unsigned integral type which
  28    will be used for hard reg sets, either alone or in an array.
  29
  30    If HARD_REG_SET is a macro, its definition is HARD_REG_ELT_TYPE,
  31    and it has enough bits to represent all the target machine's hard
  32    registers.  Otherwise, it is a typedef for a suitably sized array
  33    of HARD_REG_ELT_TYPEs.  HARD_REG_SET_LONGS is defined as how many.
  34
  35    Note that lots of code assumes that the first part of a regset is
  36    the same format as a HARD_REG_SET.  To help make sure this is true,
  37    we only try the widest fast integer mode (HOST_WIDEST_FAST_INT)
  38    instead of all the smaller types.  This approach loses only if
  39    there are very few registers and then only in the few cases where
  40    we have an array of HARD_REG_SETs, so it needn't be as complex as
  41    it used to be.  */
  42
  43 typedef unsigned HOST_WIDEST_FAST_INT HARD_REG_ELT_TYPE;
  44
  45 #if FIRST_PSEUDO_REGISTER <= HOST_BITS_PER_WIDEST_FAST_INT
  46
  47 typedef HARD_REG_ELT_TYPE HARD_REG_SET;
  48 typedef const HARD_REG_SET const_hard_reg_set;
  49
  50 #else
  51
  52 #define HARD_REG_SET_LONGS \
  53  ((FIRST_PSEUDO_REGISTER + HOST_BITS_PER_WIDEST_FAST_INT - 1)   \
  54   / HOST_BITS_PER_WIDEST_FAST_INT)
  55
  56 struct HARD_REG_SET
  57 {
  58   HARD_REG_SET
  59   operator~ () const
  60   {
  61     HARD_REG_SET res;
  62     for (unsigned int i = 0; i < ARRAY_SIZE (elts); ++i)
  63       res.elts[i] = ~elts[i];
  64     return res;
  65   }
  66
  67   HARD_REG_SET
  68   operator& (const HARD_REG_SET &other) const
  69   {
  70     HARD_REG_SET res;
  71     for (unsigned int i = 0; i < ARRAY_SIZE (elts); ++i)
  72       res.elts[i] = elts[i] & other.elts[i];
  73     return res;
  74   }
  75
  76   HARD_REG_SET &
  77   operator&= (const HARD_REG_SET &other)
  78   {
  79     for (unsigned int i = 0; i < ARRAY_SIZE (elts); ++i)
  80       elts[i] &= other.elts[i];
  81     return *this;
  82   }
  83
  84   HARD_REG_SET
  85   operator| (const HARD_REG_SET &other) const
  86   {
  87     HARD_REG_SET res;
  88     for (unsigned int i = 0; i < ARRAY_SIZE (elts); ++i)
  89       res.elts[i] = elts[i] | other.elts[i];
  90     return res;
  91   }
  92
  93   HARD_REG_SET &
  94   operator|= (const HARD_REG_SET &other)
  95   {
  96     for (unsigned int i = 0; i < ARRAY_SIZE (elts); ++i)
  97       elts[i] |= other.elts[i];
  98     return *this;
  99   }
 100
 101   bool
 102   operator== (const HARD_REG_SET &other) const
 103   {
 104     HARD_REG_ELT_TYPE bad = 0;
 105     for (unsigned int i = 0; i < ARRAY_SIZE (elts); ++i)
 106       bad |= (elts[i] ^ other.elts[i]);
 107     return bad == 0;
 108   }
 109
 110   bool
 111   operator!= (const HARD_REG_SET &other) const
 112   {
 113     return !operator== (other);
 114   }
 115
 116   HARD_REG_ELT_TYPE elts[HARD_REG_SET_LONGS];
 117 };
 118 typedef const HARD_REG_SET &const_hard_reg_set;
 119
 120 template<>
 121 struct array_traits<HARD_REG_SET>
 122 {
 123   typedef HARD_REG_ELT_TYPE element_type;
 124   static const bool has_constant_size = true;
 125   static const size_t constant_size = HARD_REG_SET_LONGS;
 126   static const element_type *base (const HARD_REG_SET &x) { return x.elts; }
 127   static size_t size (const HARD_REG_SET &) { return HARD_REG_SET_LONGS; }
 128 };
 129
 130 #endif
 131
 132 /* HARD_REG_SET wrapped into a structure, to make it possible to
 133    use HARD_REG_SET even in APIs that should not include
 134    hard-reg-set.h.  */
 135 struct hard_reg_set_container
 136 {
 137   HARD_REG_SET set;
 138 };
 139
 140 /* HARD_CONST is used to cast a constant to the appropriate type
 141    for use with a HARD_REG_SET.  */
 142
 143 #define HARD_CONST(X) ((HARD_REG_ELT_TYPE) (X))
 144
 145 /* Define macros SET_HARD_REG_BIT, CLEAR_HARD_REG_BIT and TEST_HARD_REG_BIT
 146    to set, clear or test one bit in a hard reg set of type HARD_REG_SET.
 147    All three take two arguments: the set and the register number.
 148
 149    In the case where sets are arrays of longs, the first argument
 150    is actually a pointer to a long.
 151
 152    Define two macros for initializing a set:
 153    CLEAR_HARD_REG_SET and SET_HARD_REG_SET.
 154    These take just one argument.
 155
 156    Also define:
 157
 158    hard_reg_set_subset_p (X, Y), which returns true if X is a subset of Y.
 159    hard_reg_set_intersect_p (X, Y), which returns true if X and Y intersect.
 160    hard_reg_set_empty_p (X), which returns true if X is empty.  */
 161
 162 #define UHOST_BITS_PER_WIDE_INT ((unsigned) HOST_BITS_PER_WIDEST_FAST_INT)
 163
 164 #if FIRST_PSEUDO_REGISTER <= HOST_BITS_PER_WIDEST_FAST_INT
 165
 166 #define SET_HARD_REG_BIT(SET, BIT)  \
 167  ((SET) |= HARD_CONST (1) << (BIT))
 168 #define CLEAR_HARD_REG_BIT(SET, BIT)  \
 169  ((SET) &= ~(HARD_CONST (1) << (BIT)))
 170 #define TEST_HARD_REG_BIT(SET, BIT)  \
 171  (!!((SET) & (HARD_CONST (1) << (BIT))))
 172
 173 #define CLEAR_HARD_REG_SET(TO) ((TO) = HARD_CONST (0))
 174 #define SET_HARD_REG_SET(TO) ((TO) = ~ HARD_CONST (0))
 175
 176 static inline bool
 177 hard_reg_set_subset_p (const_hard_reg_set x, const_hard_reg_set y)
 178 {
 179   return (x & ~y) == HARD_CONST (0);
 180 }
 181
 182 static inline bool
 183 hard_reg_set_intersect_p (const_hard_reg_set x, const_hard_reg_set y)
 184 {
 185   return (x & y) != HARD_CONST (0);
 186 }
 187
 188 static inline bool
 189 hard_reg_set_empty_p (const_hard_reg_set x)
 190 {
 191   return x == HARD_CONST (0);
 192 }
 193
 194 #else
 195
 196 inline void
 197 SET_HARD_REG_BIT (HARD_REG_SET &set, unsigned int bit)
 198 {
 199   set.elts[bit / UHOST_BITS_PER_WIDE_INT]
 200     |= HARD_CONST (1) << (bit % UHOST_BITS_PER_WIDE_INT);
 201 }
 202
 203 inline void
 204 CLEAR_HARD_REG_BIT (HARD_REG_SET &set, unsigned int bit)
 205 {
 206   set.elts[bit / UHOST_BITS_PER_WIDE_INT]
 207     &= ~(HARD_CONST (1) << (bit % UHOST_BITS_PER_WIDE_INT));
 208 }
 209
 210 inline bool
 211 TEST_HARD_REG_BIT (const_hard_reg_set set, unsigned int bit)
 212 {
 213   return (set.elts[bit / UHOST_BITS_PER_WIDE_INT]
 214           & (HARD_CONST (1) << (bit % UHOST_BITS_PER_WIDE_INT)));
 215 }
 216
 217 inline void
 218 CLEAR_HARD_REG_SET (HARD_REG_SET &set)
 219 {
 220   for (unsigned int i = 0; i < ARRAY_SIZE (set.elts); ++i)
 221     set.elts[i] = 0;
 222 }
 223
 224 inline void
 225 SET_HARD_REG_SET (HARD_REG_SET &set)
 226 {
 227   for (unsigned int i = 0; i < ARRAY_SIZE (set.elts); ++i)
 228     set.elts[i] = -1;
 229 }
 230
 231 static inline bool
 232 hard_reg_set_subset_p (const_hard_reg_set x, const_hard_reg_set y)
 233 {
 234   HARD_REG_ELT_TYPE bad = 0;
 235   for (unsigned int i = 0; i < ARRAY_SIZE (x.elts); ++i)
 236     bad |= (x.elts[i] & ~y.elts[i]);
 237   return bad == 0;
 238 }
 239
 240 static inline bool
 241 hard_reg_set_intersect_p (const_hard_reg_set x, const_hard_reg_set y)
 242 {
 243   HARD_REG_ELT_TYPE good = 0;
 244   for (unsigned int i = 0; i < ARRAY_SIZE (x.elts); ++i)
 245     good |= (x.elts[i] & y.elts[i]);
 246   return good != 0;
 247 }
 248
 249 static inline bool
 250 hard_reg_set_empty_p (const_hard_reg_set x)
 251 {
 252   HARD_REG_ELT_TYPE bad = 0;
 253   for (unsigned int i = 0; i < ARRAY_SIZE (x.elts); ++i)
 254     bad |= x.elts[i];
 255   return bad == 0;
 256 }
 257 #endif
 258
 259 /* Iterator for hard register sets.  */
 260
 261 struct hard_reg_set_iterator
 262 {
 263   /* Pointer to the current element.  */
 264   const HARD_REG_ELT_TYPE *pelt;
 265
 266   /* The length of the set.  */
 267   unsigned short length;
 268
 269   /* Word within the current element.  */
 270   unsigned short word_no;
 271
 272   /* Contents of the actually processed word.  When finding next bit
 273      it is shifted right, so that the actual bit is always the least
 274      significant bit of ACTUAL.  */
 275   HARD_REG_ELT_TYPE bits;
 276 };
 277
 278 #define HARD_REG_ELT_BITS UHOST_BITS_PER_WIDE_INT
 279
 280 /* The implementation of the iterator functions is fully analogous to
 281    the bitmap iterators.  */
 282 static inline void
 283 hard_reg_set_iter_init (hard_reg_set_iterator *iter, const_hard_reg_set set,
 284                         unsigned min, unsigned *regno)
 285 {
 286 #ifdef HARD_REG_SET_LONGS
 287   iter->pelt = set.elts;
 288   iter->length = HARD_REG_SET_LONGS;
 289 #else
 290   iter->pelt = &set;
 291   iter->length = 1;
 292 #endif
 293   iter->word_no = min / HARD_REG_ELT_BITS;
 294   if (iter->word_no < iter->length)
 295     {
 296       iter->bits = iter->pelt[iter->word_no];
 297       iter->bits >>= min % HARD_REG_ELT_BITS;
 298
 299       /* This is required for correct search of the next bit.  */
 300       min += !iter->bits;
 301     }
 302   *regno = min;
 303 }
 304
 305 static inline bool
 306 hard_reg_set_iter_set (hard_reg_set_iterator *iter, unsigned *regno)
 307 {
 308   while (1)
 309     {
 310       /* Return false when we're advanced past the end of the set.  */
 311       if (iter->word_no >= iter->length)
 312         return false;
 313
 314       if (iter->bits)
 315         {
 316           /* Find the correct bit and return it.  */
 317           while (!(iter->bits & 1))
 318             {
 319               iter->bits >>= 1;
 320               *regno += 1;
 321             }
 322           return (*regno < FIRST_PSEUDO_REGISTER);
 323         }
 324
 325       /* Round to the beginning of the next word.  */
 326       *regno = (*regno + HARD_REG_ELT_BITS - 1);
 327       *regno -= *regno % HARD_REG_ELT_BITS;
 328
 329       /* Find the next non-zero word.  */
 330       while (++iter->word_no < iter->length)
 331         {
 332           iter->bits = iter->pelt[iter->word_no];
 333           if (iter->bits)
 334             break;
 335           *regno += HARD_REG_ELT_BITS;
 336         }
 337     }
 338 }
 339
 340 static inline void
 341 hard_reg_set_iter_next (hard_reg_set_iterator *iter, unsigned *regno)
 342 {
 343   iter->bits >>= 1;
 344   *regno += 1;
 345 }
 346
 347 #define EXECUTE_IF_SET_IN_HARD_REG_SET(SET, MIN, REGNUM, ITER)          \
 348   for (hard_reg_set_iter_init (&(ITER), (SET), (MIN), &(REGNUM));       \
 349        hard_reg_set_iter_set (&(ITER), &(REGNUM));                      \
 350        hard_reg_set_iter_next (&(ITER), &(REGNUM)))
 351
 352
 353 /* Define some standard sets of registers.  */
 354
 355 /* Indexed by hard register number, contains 1 for registers
 356    that are being used for global register decls.
 357    These must be exempt from ordinary flow analysis
 358    and are also considered fixed.  */
 359
 360 extern char global_regs[FIRST_PSEUDO_REGISTER];
 361
 362 extern HARD_REG_SET global_reg_set;
 363
 364 class simplifiable_subreg;
 365 class subreg_shape;
 366
 367 struct simplifiable_subregs_hasher : nofree_ptr_hash <simplifiable_subreg>
 368 {
 369   typedef const subreg_shape *compare_type;
 370
 371   static inline hashval_t hash (const simplifiable_subreg *);
 372   static inline bool equal (const simplifiable_subreg *, const subreg_shape *);
 373 };
 374
 375 struct target_hard_regs {
 376   void finalize ();
 377
 378   /* The set of registers that actually exist on the current target.  */
 379   HARD_REG_SET x_accessible_reg_set;
 380
 381   /* The set of registers that should be considered to be register
 382      operands.  It is a subset of x_accessible_reg_set.  */
 383   HARD_REG_SET x_operand_reg_set;
 384
 385   /* Indexed by hard register number, contains 1 for registers
 386      that are fixed use (stack pointer, pc, frame pointer, etc.;.
 387      These are the registers that cannot be used to allocate
 388      a pseudo reg whose life does not cross calls.  */
 389   char x_fixed_regs[FIRST_PSEUDO_REGISTER];
 390
 391   /* The same info as a HARD_REG_SET.  */
 392   HARD_REG_SET x_fixed_reg_set;
 393
 394   /* Indexed by hard register number, contains 1 for registers
 395      that are fixed use or are clobbered by function calls.
 396      These are the registers that cannot be used to allocate
 397      a pseudo reg whose life crosses calls.  */
 398   char x_call_used_regs[FIRST_PSEUDO_REGISTER];
 399
 400   /* For targets that use reload rather than LRA, this is the set
 401      of registers that we are able to save and restore around calls
 402      (i.e. those for which we know a suitable mode and set of
 403      load/store instructions exist).  For LRA targets it contains
 404      all registers.
 405
 406      This is legacy information and should be removed if all targets
 407      switch to LRA.  */
 408   HARD_REG_SET x_savable_regs;
 409
 410   /* Contains registers that are fixed use -- i.e. in fixed_reg_set -- but
 411      only if they are not merely part of that set because they are global
 412      regs.  Global regs that are not otherwise fixed can still take part
 413      in register allocation.  */
 414   HARD_REG_SET x_fixed_nonglobal_reg_set;
 415
 416   /* Contains 1 for registers that are set or clobbered by calls.  */
 417   /* ??? Ideally, this would be just call_used_regs plus global_regs, but
 418      for someone's bright idea to have call_used_regs strictly include
 419      fixed_regs.  Which leaves us guessing as to the set of fixed_regs
 420      that are actually preserved.  We know for sure that those associated
 421      with the local stack frame are safe, but scant others.  */
 422   HARD_REG_SET x_regs_invalidated_by_call;
 423
 424   /* Table of register numbers in the order in which to try to use them.  */
 425   int x_reg_alloc_order[FIRST_PSEUDO_REGISTER];
 426
 427   /* The inverse of reg_alloc_order.  */
 428   int x_inv_reg_alloc_order[FIRST_PSEUDO_REGISTER];
 429
 430   /* For each reg class, a HARD_REG_SET saying which registers are in it.  */
 431   HARD_REG_SET x_reg_class_contents[N_REG_CLASSES];
 432
 433   /* For each reg class, a boolean saying whether the class contains only
 434      fixed registers.  */
 435   bool x_class_only_fixed_regs[N_REG_CLASSES];
 436
 437   /* For each reg class, number of regs it contains.  */
 438   unsigned int x_reg_class_size[N_REG_CLASSES];
 439
 440   /* For each reg class, table listing all the classes contained in it.  */
 441   enum reg_class x_reg_class_subclasses[N_REG_CLASSES][N_REG_CLASSES];
 442
 443   /* For each pair of reg classes,
 444      a largest reg class contained in their union.  */
 445   enum reg_class x_reg_class_subunion[N_REG_CLASSES][N_REG_CLASSES];
 446
 447   /* For each pair of reg classes,
 448      the smallest reg class that contains their union.  */
 449   enum reg_class x_reg_class_superunion[N_REG_CLASSES][N_REG_CLASSES];
 450
 451   /* Vector indexed by hardware reg giving its name.  */
 452   const char *x_reg_names[FIRST_PSEUDO_REGISTER];
 453
 454   /* Records which registers can form a particular subreg, with the subreg
 455      being identified by its outer mode, inner mode and offset.  */
 456   hash_table <simplifiable_subregs_hasher> *x_simplifiable_subregs;
 457 };
 458
 459 extern struct target_hard_regs default_target_hard_regs;
 460 #if SWITCHABLE_TARGET
 461 extern struct target_hard_regs *this_target_hard_regs;
 462 #else
 463 #define this_target_hard_regs (&default_target_hard_regs)
 464 #endif
 465
 466 #define accessible_reg_set \
 467   (this_target_hard_regs->x_accessible_reg_set)
 468 #define operand_reg_set \
 469   (this_target_hard_regs->x_operand_reg_set)
 470 #define fixed_regs \
 471   (this_target_hard_regs->x_fixed_regs)
 472 #define fixed_reg_set \
 473   (this_target_hard_regs->x_fixed_reg_set)
 474 #define fixed_nonglobal_reg_set \
 475   (this_target_hard_regs->x_fixed_nonglobal_reg_set)
 476 #ifdef IN_TARGET_CODE
 477 #define call_used_regs \
 478   (this_target_hard_regs->x_call_used_regs)
 479 #endif
 480 #define savable_regs \
 481   (this_target_hard_regs->x_savable_regs)
 482 #ifdef IN_TARGET_CODE
 483 #define regs_invalidated_by_call \
 484   (this_target_hard_regs->x_regs_invalidated_by_call)
 485 #define call_used_or_fixed_regs \
 486   (regs_invalidated_by_call | fixed_reg_set)
 487 #endif
 488 #define reg_alloc_order \
 489   (this_target_hard_regs->x_reg_alloc_order)
 490 #define inv_reg_alloc_order \
 491   (this_target_hard_regs->x_inv_reg_alloc_order)
 492 #define reg_class_contents \
 493   (this_target_hard_regs->x_reg_class_contents)
 494 #define class_only_fixed_regs \
 495   (this_target_hard_regs->x_class_only_fixed_regs)
 496 #define reg_class_size \
 497   (this_target_hard_regs->x_reg_class_size)
 498 #define reg_class_subclasses \
 499   (this_target_hard_regs->x_reg_class_subclasses)
 500 #define reg_class_subunion \
 501   (this_target_hard_regs->x_reg_class_subunion)
 502 #define reg_class_superunion \
 503   (this_target_hard_regs->x_reg_class_superunion)
 504 #define reg_names \
 505   (this_target_hard_regs->x_reg_names)
 506
 507 /* Vector indexed by reg class giving its name.  */
 508
 509 extern const char * reg_class_names[];
 510
 511 /* Given a hard REGN a FROM mode and a TO mode, return true if
 512    REGN can change from mode FROM to mode TO.  */
 513 #define REG_CAN_CHANGE_MODE_P(REGN, FROM, TO)                          \
 514   (targetm.can_change_mode_class (FROM, TO, REGNO_REG_CLASS (REGN)))
 515
 516 #ifdef IN_TARGET_CODE
 517 /* Return true if register REGNO is either fixed or call-used
 518    (aka call-clobbered).  */
 519
 520 inline bool
 521 call_used_or_fixed_reg_p (unsigned int regno)
 522 {
 523   return fixed_regs[regno] || this_target_hard_regs->x_call_used_regs[regno];
 524 }
 525 #endif
 526
 527 #endif /* ! GCC_HARD_REG_SET_H */