gcc/recog.h

   1 /* Declarations for interface to insn recognizer and insn-output.cc.
   2    Copyright (C) 1987-2023 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_RECOG_H
  21 #define GCC_RECOG_H
  22
  23 /* For enum tree_code ERROR_MARK.  */
  24 #include "tree.h"
  25
  26 /* Random number that should be large enough for all purposes.  Also define
  27    a type that has at least MAX_RECOG_ALTERNATIVES + 1 bits, with the extra
  28    bit giving an invalid value that can be used to mean "uninitialized".  */
  29 #define MAX_RECOG_ALTERNATIVES 35
  30 typedef uint64_t alternative_mask;  /* Keep in sync with genattrtab.cc.  */
  31
  32 /* A mask of all alternatives.  */
  33 #define ALL_ALTERNATIVES ((alternative_mask) -1)
  34
  35 /* A mask containing just alternative X.  */
  36 #define ALTERNATIVE_BIT(X) ((alternative_mask) 1 << (X))
  37
  38 /* Types of operands.  */
  39 enum op_type {
  40   OP_IN,
  41   OP_OUT,
  42   OP_INOUT
  43 };
  44
  45 #ifndef GENERATOR_FILE
  46 struct operand_alternative
  47 {
  48   /* Pointer to the beginning of the constraint string for this alternative,
  49      for easier access by alternative number.  */
  50   const char *constraint;
  51
  52   /* The register class valid for this alternative (possibly NO_REGS).  */
  53   ENUM_BITFIELD (reg_class) cl : 16;
  54
  55   /* "Badness" of this alternative, computed from number of '?' and '!'
  56      characters in the constraint string.  */
  57   unsigned int reject : 16;
  58
  59   /* -1 if no matching constraint was found, or an operand number.  */
  60   int matches : 8;
  61   /* The same information, but reversed: -1 if this operand is not
  62      matched by any other, or the operand number of the operand that
  63      matches this one.  */
  64   int matched : 8;
  65
  66   /* Bit ID is set if the constraint string includes a register constraint with
  67      register filter ID.  Use test_register_filters (REGISTER_FILTERS, REGNO)
  68      to test whether REGNO is a valid start register for the operand.  */
  69   unsigned int register_filters : MAX (NUM_REGISTER_FILTERS, 1);
  70
  71   /* Nonzero if '&' was found in the constraint string.  */
  72   unsigned int earlyclobber : 1;
  73   /* Nonzero if TARGET_MEM_CONSTRAINT was found in the constraint
  74      string.  */
  75   unsigned int memory_ok : 1;
  76   /* Nonzero if 'p' was found in the constraint string.  */
  77   unsigned int is_address : 1;
  78   /* Nonzero if 'X' was found in the constraint string, or if the constraint
  79      string for this alternative was empty.  */
  80   unsigned int anything_ok : 1;
  81 };
  82
  83 /* Return the class for operand I of alternative ALT, taking matching
  84    constraints into account.  */
  85
  86 inline enum reg_class
  87 alternative_class (const operand_alternative *alt, int i)
  88 {
  89   return alt[i].matches >= 0 ? alt[alt[i].matches].cl : alt[i].cl;
  90 }
  91
  92 /* Return the mask of register filters that should be applied to operand I
  93    of alternative ALT, taking matching constraints into account.  */
  94
  95 inline unsigned int
  96 alternative_register_filters (const operand_alternative *alt, int i)
  97 {
  98   return (alt[i].matches >= 0
  99           ? alt[alt[i].matches].register_filters
 100           : alt[i].register_filters);
 101 }
 102 #endif
 103
 104 /* A class for substituting one rtx for another within an instruction,
 105    or for recursively simplifying the instruction as-is.  Derived classes
 106    can record or filter certain decisions.  */
 107
 108 class insn_propagation : public simplify_context
 109 {
 110 public:
 111   /* Assignments for RESULT_FLAGS.
 112
 113      UNSIMPLIFIED is true if a substitution has been made inside an rtx
 114      X and if neither X nor its parent expressions could be simplified.
 115
 116      FIRST_SPARE_RESULT is the first flag available for derived classes.  */
 117   static const uint16_t UNSIMPLIFIED = 1U << 0;
 118   static const uint16_t FIRST_SPARE_RESULT = 1U << 1;
 119
 120   insn_propagation (rtx_insn *);
 121   insn_propagation (rtx_insn *, rtx, rtx, bool = true);
 122   bool apply_to_pattern (rtx *);
 123   bool apply_to_rvalue (rtx *);
 124
 125   /* Return true if we should accept a substitution into the address of
 126      memory expression MEM.  Undoing changes OLD_NUM_CHANGES and up restores
 127      MEM's original address.  */
 128   virtual bool check_mem (int /*old_num_changes*/,
 129                           rtx /*mem*/) { return true; }
 130
 131   /* Note that we've simplified OLD_RTX into NEW_RTX.  When substituting,
 132      this only happens if a substitution occured within OLD_RTX.
 133      Undoing OLD_NUM_CHANGES and up will restore the old form of OLD_RTX.
 134      OLD_RESULT_FLAGS is the value that RESULT_FLAGS had before processing
 135      OLD_RTX.  */
 136   virtual void note_simplification (int /*old_num_changes*/,
 137                                     uint16_t /*old_result_flags*/,
 138                                     rtx /*old_rtx*/, rtx /*new_rtx*/) {}
 139
 140 private:
 141   bool apply_to_mem_1 (rtx);
 142   bool apply_to_lvalue_1 (rtx);
 143   bool apply_to_rvalue_1 (rtx *);
 144   bool apply_to_pattern_1 (rtx *);
 145
 146 public:
 147   /* The instruction that we are simplifying or propagating into.  */
 148   rtx_insn *insn;
 149
 150   /* If FROM is nonnull, we're replacing FROM with TO, otherwise we're
 151      just doing a recursive simplification.  */
 152   rtx from;
 153   rtx to;
 154
 155   /* The number of times that we have replaced FROM with TO.  */
 156   unsigned int num_replacements;
 157
 158   /* A bitmask of flags that describe the result of the simplificiation;
 159      see above for details.  */
 160   uint16_t result_flags : 16;
 161
 162   /* True if we should unshare TO when making the next substitution,
 163      false if we can use TO itself.  */
 164   uint16_t should_unshare : 1;
 165
 166   /* True if we should call check_mem after substituting into a memory.  */
 167   uint16_t should_check_mems : 1;
 168
 169   /* True if we should call note_simplification after each simplification.  */
 170   uint16_t should_note_simplifications : 1;
 171
 172   /* For future expansion.  */
 173   uint16_t spare : 13;
 174
 175   /* Gives the reason that a substitution failed, for debug purposes.  */
 176   const char *failure_reason;
 177 };
 178
 179 /* Try to replace FROM with TO in INSN.  SHARED_P is true if TO is shared
 180    with other instructions, false if INSN can use TO directly.  */
 181
 182 inline insn_propagation::insn_propagation (rtx_insn *insn, rtx from, rtx to,
 183                                            bool shared_p)
 184   : insn (insn),
 185     from (from),
 186     to (to),
 187     num_replacements (0),
 188     result_flags (0),
 189     should_unshare (shared_p),
 190     should_check_mems (false),
 191     should_note_simplifications (false),
 192     spare (0),
 193     failure_reason (nullptr)
 194 {
 195 }
 196
 197 /* Try to simplify INSN without performing a substitution.  */
 198
 199 inline insn_propagation::insn_propagation (rtx_insn *insn)
 200   : insn_propagation (insn, NULL_RTX, NULL_RTX)
 201 {
 202 }
 203
 204 extern void init_recog (void);
 205 extern void init_recog_no_volatile (void);
 206 extern bool check_asm_operands (rtx);
 207 extern int asm_operand_ok (rtx, const char *, const char **);
 208 extern bool validate_change (rtx, rtx *, rtx, bool);
 209 extern bool validate_unshare_change (rtx, rtx *, rtx, bool);
 210 extern bool validate_change_xveclen (rtx, rtx *, int, bool);
 211 extern bool canonicalize_change_group (rtx_insn *insn, rtx x);
 212 extern bool insn_invalid_p (rtx_insn *, bool);
 213 extern bool verify_changes (int);
 214 extern void confirm_change_group (void);
 215 extern bool apply_change_group (void);
 216 extern int num_validated_changes (void);
 217 extern void cancel_changes (int);
 218 extern void temporarily_undo_changes (int);
 219 extern void redo_changes (int);
 220 extern bool constrain_operands (int, alternative_mask);
 221 extern bool constrain_operands_cached (rtx_insn *, int);
 222 extern bool memory_address_addr_space_p (machine_mode, rtx, addr_space_t,
 223                                          code_helper = ERROR_MARK);
 224 #define memory_address_p(mode,addr) \
 225         memory_address_addr_space_p ((mode), (addr), ADDR_SPACE_GENERIC)
 226 extern bool strict_memory_address_addr_space_p (machine_mode, rtx, addr_space_t,
 227                                                 code_helper = ERROR_MARK);
 228 #define strict_memory_address_p(mode,addr) \
 229         strict_memory_address_addr_space_p ((mode), (addr), ADDR_SPACE_GENERIC)
 230 extern bool validate_replace_rtx_subexp (rtx, rtx, rtx_insn *, rtx *);
 231 extern bool validate_replace_rtx (rtx, rtx, rtx_insn *);
 232 extern bool validate_replace_rtx_part (rtx, rtx, rtx *, rtx_insn *);
 233 extern bool validate_replace_rtx_part_nosimplify (rtx, rtx, rtx *, rtx_insn *);
 234 extern void validate_replace_rtx_group (rtx, rtx, rtx_insn *);
 235 extern void validate_replace_src_group (rtx, rtx, rtx_insn *);
 236 extern bool validate_simplify_insn (rtx_insn *insn);
 237 extern int num_changes_pending (void);
 238 extern bool reg_fits_class_p (const_rtx, reg_class_t, int, machine_mode);
 239 extern bool valid_insn_p (rtx_insn *);
 240
 241 extern bool offsettable_memref_p (rtx);
 242 extern bool offsettable_nonstrict_memref_p (rtx);
 243 extern bool offsettable_address_addr_space_p (int, machine_mode, rtx,
 244                                              addr_space_t);
 245 #define offsettable_address_p(strict,mode,addr) \
 246         offsettable_address_addr_space_p ((strict), (mode), (addr), \
 247                                           ADDR_SPACE_GENERIC)
 248 extern bool mode_dependent_address_p (rtx, addr_space_t);
 249
 250 extern int recog (rtx, rtx_insn *, int *);
 251 #ifndef GENERATOR_FILE
 252 inline int recog_memoized (rtx_insn *insn);
 253 #endif
 254 extern void add_clobbers (rtx, int);
 255 extern bool added_clobbers_hard_reg_p (int);
 256 extern void insn_extract (rtx_insn *);
 257 extern void extract_insn (rtx_insn *);
 258 extern void extract_constrain_insn (rtx_insn *insn);
 259 extern void extract_constrain_insn_cached (rtx_insn *);
 260 extern void extract_insn_cached (rtx_insn *);
 261 #ifndef GENERATOR_FILE
 262 extern void preprocess_constraints (int, int, const char **,
 263                                     operand_alternative *, rtx **);
 264 extern const operand_alternative *preprocess_insn_constraints (unsigned int);
 265 #endif
 266 extern void preprocess_constraints (rtx_insn *);
 267 extern rtx_insn *peep2_next_insn (int);
 268 extern bool peep2_regno_dead_p (int, int);
 269 extern bool peep2_reg_dead_p (int, rtx);
 270 #ifdef HARD_CONST
 271 extern rtx peep2_find_free_register (int, int, const char *,
 272                                      machine_mode, HARD_REG_SET *);
 273 #endif
 274 extern rtx_insn *peephole2_insns (rtx, rtx_insn *, int *);
 275
 276 extern bool store_data_bypass_p (rtx_insn *, rtx_insn *);
 277 extern bool if_test_bypass_p (rtx_insn *, rtx_insn *);
 278
 279 extern void copy_frame_info_to_split_insn (rtx_insn *, rtx_insn *);
 280
 281 #ifndef GENERATOR_FILE
 282 /* Try recognizing the instruction INSN,
 283    and return the code number that results.
 284    Remember the code so that repeated calls do not
 285    need to spend the time for actual rerecognition.
 286
 287    This function is the normal interface to instruction recognition.
 288    The automatically-generated function `recog' is normally called
 289    through this one.  */
 290
 291 inline int
 292 recog_memoized (rtx_insn *insn)
 293 {
 294   if (INSN_CODE (insn) < 0)
 295     INSN_CODE (insn) = recog (PATTERN (insn), insn, 0);
 296   return INSN_CODE (insn);
 297 }
 298 #endif
 299
 300 /* Skip chars until the next ',' or the end of the string.  This is
 301    useful to skip alternatives in a constraint string.  */
 302 inline const char *
 303 skip_alternative (const char *p)
 304 {
 305   const char *r = p;
 306   while (*r != '\0' && *r != ',')
 307     r++;
 308   if (*r == ',')
 309     r++;
 310   return r;
 311 }
 312
 313 /* Nonzero means volatile operands are recognized.  */
 314 extern int volatile_ok;
 315
 316 /* RAII class for temporarily setting volatile_ok.  */
 317
 318 class temporary_volatile_ok
 319 {
 320 public:
 321   temporary_volatile_ok (int value) : save_volatile_ok (volatile_ok)
 322   {
 323     volatile_ok = value;
 324   }
 325
 326   ~temporary_volatile_ok () { volatile_ok = save_volatile_ok; }
 327
 328 private:
 329   temporary_volatile_ok (const temporary_volatile_ok &);
 330   int save_volatile_ok;
 331 };
 332
 333 /* Set by constrain_operands to the number of the alternative that
 334    matched.  */
 335 extern int which_alternative;
 336
 337 /* The following vectors hold the results from insn_extract.  */
 338
 339 struct recog_data_d
 340 {
 341   /* It is very tempting to make the 5 operand related arrays into a
 342      structure and index on that.  However, to be source compatible
 343      with all of the existing md file insn constraints and output
 344      templates, we need `operand' as a flat array.  Without that
 345      member, making an array for the rest seems pointless.  */
 346
 347   /* Gives value of operand N.  */
 348   rtx operand[MAX_RECOG_OPERANDS];
 349
 350   /* Gives location where operand N was found.  */
 351   rtx *operand_loc[MAX_RECOG_OPERANDS];
 352
 353   /* Gives the constraint string for operand N.  */
 354   const char *constraints[MAX_RECOG_OPERANDS];
 355
 356   /* Nonzero if operand N is a match_operator or a match_parallel.  */
 357   char is_operator[MAX_RECOG_OPERANDS];
 358
 359   /* Gives the mode of operand N.  */
 360   machine_mode operand_mode[MAX_RECOG_OPERANDS];
 361
 362   /* Gives the type (in, out, inout) for operand N.  */
 363   enum op_type operand_type[MAX_RECOG_OPERANDS];
 364
 365   /* Gives location where the Nth duplicate-appearance of an operand
 366      was found.  This is something that matched MATCH_DUP.  */
 367   rtx *dup_loc[MAX_DUP_OPERANDS];
 368
 369   /* Gives the operand number that was duplicated in the Nth
 370      duplicate-appearance of an operand.  */
 371   char dup_num[MAX_DUP_OPERANDS];
 372
 373   /* ??? Note that these are `char' instead of `unsigned char' to (try to)
 374      avoid certain lossage from K&R C, wherein `unsigned char' default
 375      promotes to `unsigned int' instead of `int' as in ISO C.  As of 1999,
 376      the most common places to bootstrap from K&R C are SunOS and HPUX,
 377      both of which have signed characters by default.  The only other
 378      supported natives that have both K&R C and unsigned characters are
 379      ROMP and Irix 3, and neither have been seen for a while, but do
 380      continue to consider unsignedness when performing arithmetic inside
 381      a comparison.  */
 382
 383   /* The number of operands of the insn.  */
 384   char n_operands;
 385
 386   /* The number of MATCH_DUPs in the insn.  */
 387   char n_dups;
 388
 389   /* The number of alternatives in the constraints for the insn.  */
 390   char n_alternatives;
 391
 392   /* True if insn is ASM_OPERANDS.  */
 393   bool is_asm;
 394
 395   /* In case we are caching, hold insn data was generated for.  */
 396   rtx_insn *insn;
 397 };
 398
 399 extern struct recog_data_d recog_data;
 400
 401 /* RAII class for saving/restoring recog_data.  */
 402
 403 class recog_data_saver
 404 {
 405   recog_data_d m_saved_data;
 406 public:
 407   recog_data_saver () : m_saved_data (recog_data) {}
 408   ~recog_data_saver () { recog_data = m_saved_data; }
 409 };
 410
 411 #ifndef GENERATOR_FILE
 412 extern const operand_alternative *recog_op_alt;
 413
 414 /* Return a pointer to an array in which index OP describes the constraints
 415    on operand OP of the current instruction alternative (which_alternative).
 416    Only valid after calling preprocess_constraints and constrain_operands.  */
 417
 418 inline const operand_alternative *
 419 which_op_alt ()
 420 {
 421   gcc_checking_assert (IN_RANGE (which_alternative, 0,
 422                                  recog_data.n_alternatives - 1));
 423   return &recog_op_alt[which_alternative * recog_data.n_operands];
 424 }
 425 #endif
 426
 427 /* A table defined in insn-output.cc that give information about
 428    each insn-code value.  */
 429
 430 typedef bool (*insn_operand_predicate_fn) (rtx, machine_mode);
 431 typedef const char * (*insn_output_fn) (rtx *, rtx_insn *);
 432
 433 struct insn_gen_fn
 434 {
 435   typedef void (*stored_funcptr) (void);
 436
 437   template<typename ...Ts>
 438   rtx_insn *operator() (Ts... args) const
 439   {
 440     typedef rtx_insn *(*funcptr) (decltype ((void) args, NULL_RTX)...);
 441     return ((funcptr) func) (args...);
 442   }
 443
 444   // This is for compatibility of code that invokes functions like
 445   //   (*funcptr) (arg)
 446   insn_gen_fn operator * (void) const { return *this; }
 447
 448   // The wrapped function pointer must be public and there must not be any
 449   // constructors.  Otherwise the insn_data_d struct initializers generated
 450   // by genoutput.cc will result in static initializer functions, which defeats
 451   // the purpose of the generated insn_data_d array.
 452   stored_funcptr func;
 453 };
 454
 455 struct insn_operand_data
 456 {
 457   const insn_operand_predicate_fn predicate;
 458
 459   const char *const constraint;
 460
 461   ENUM_BITFIELD(machine_mode) const mode : 16;
 462
 463   const char strict_low;
 464
 465   const char is_operator;
 466
 467   const char eliminable;
 468
 469   const char allows_mem;
 470 };
 471
 472 /* Legal values for insn_data.output_format.  Indicate what type of data
 473    is stored in insn_data.output.  */
 474 #define INSN_OUTPUT_FORMAT_NONE         0       /* abort */
 475 #define INSN_OUTPUT_FORMAT_SINGLE       1       /* const char * */
 476 #define INSN_OUTPUT_FORMAT_MULTI        2       /* const char * const * */
 477 #define INSN_OUTPUT_FORMAT_FUNCTION     3       /* const char * (*)(...) */
 478
 479 struct insn_data_d
 480 {
 481   const char *const name;
 482 #if HAVE_DESIGNATED_UNION_INITIALIZERS
 483   union {
 484     const char *single;
 485     const char *const *multi;
 486     insn_output_fn function;
 487   } output;
 488 #else
 489   struct {
 490     const char *single;
 491     const char *const *multi;
 492     insn_output_fn function;
 493   } output;
 494 #endif
 495   const insn_gen_fn genfun;
 496   const struct insn_operand_data *const operand;
 497
 498   const char n_generator_args;
 499   const char n_operands;
 500   const char n_dups;
 501   const char n_alternatives;
 502   const char output_format;
 503 };
 504
 505 extern const struct insn_data_d insn_data[];
 506 extern int peep2_current_count;
 507
 508 #ifndef GENERATOR_FILE
 509 #include "insn-codes.h"
 510
 511 /* An enum of boolean attributes that may only depend on the current
 512    subtarget, not on things like operands or compiler phase.  */
 513 enum bool_attr {
 514   BA_ENABLED,
 515   BA_PREFERRED_FOR_SPEED,
 516   BA_PREFERRED_FOR_SIZE,
 517   BA_LAST = BA_PREFERRED_FOR_SIZE
 518 };
 519
 520 /* Target-dependent globals.  */
 521 struct target_recog {
 522   bool x_initialized;
 523   alternative_mask x_bool_attr_masks[NUM_INSN_CODES][BA_LAST + 1];
 524   operand_alternative *x_op_alt[NUM_INSN_CODES];
 525 };
 526
 527 extern struct target_recog default_target_recog;
 528 #if SWITCHABLE_TARGET
 529 extern struct target_recog *this_target_recog;
 530 #else
 531 #define this_target_recog (&default_target_recog)
 532 #endif
 533
 534 alternative_mask get_enabled_alternatives (rtx_insn *);
 535 alternative_mask get_preferred_alternatives (rtx_insn *);
 536 alternative_mask get_preferred_alternatives (rtx_insn *, basic_block);
 537 bool check_bool_attrs (rtx_insn *);
 538
 539 void recog_init ();
 540
 541 /* This RAII class can help to undo tentative insn changes on failure.
 542    When an object of the class goes out of scope, it undoes all group
 543    changes that have been made via the validate_change machinery and
 544    not yet confirmed via confirm_change_group.
 545
 546    For example:
 547
 548       insn_change_watermark watermark;
 549       validate_change (..., true); // A
 550       ...
 551       if (test)
 552         // Undoes change A.
 553         return false;
 554       ...
 555       validate_change (..., true); // B
 556       ...
 557       if (test)
 558         // Undoes changes A and B.
 559         return false;
 560       ...
 561       confirm_change_group ();
 562
 563    Code that wants to avoid this behavior can use keep ():
 564
 565       insn_change_watermark watermark;
 566       validate_change (..., true); // A
 567       ...
 568       if (test)
 569         // Undoes change A.
 570         return false;
 571       ...
 572       watermark.keep ();
 573       validate_change (..., true); // B
 574       ...
 575       if (test)
 576         // Undoes change B, but not A.
 577         return false;
 578       ...
 579       confirm_change_group ();  */
 580 class insn_change_watermark
 581 {
 582 public:
 583   insn_change_watermark () : m_old_num_changes (num_validated_changes ()) {}
 584   ~insn_change_watermark ();
 585   void keep () { m_old_num_changes = num_validated_changes (); }
 586
 587 private:
 588   int m_old_num_changes;
 589 };
 590
 591 inline insn_change_watermark::~insn_change_watermark ()
 592 {
 593   if (m_old_num_changes < num_validated_changes ())
 594     cancel_changes (m_old_num_changes);
 595 }
 596
 597 #endif
 598
 599 #endif /* GCC_RECOG_H */