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 struct operand_alternative
  46 {
  47   /* Pointer to the beginning of the constraint string for this alternative,
  48      for easier access by alternative number.  */
  49   const char *constraint;
  50
  51   /* The register class valid for this alternative (possibly NO_REGS).  */
  52   ENUM_BITFIELD (reg_class) cl : 16;
  53
  54   /* "Badness" of this alternative, computed from number of '?' and '!'
  55      characters in the constraint string.  */
  56   unsigned int reject : 16;
  57
  58   /* -1 if no matching constraint was found, or an operand number.  */
  59   int matches : 8;
  60   /* The same information, but reversed: -1 if this operand is not
  61      matched by any other, or the operand number of the operand that
  62      matches this one.  */
  63   int matched : 8;
  64
  65   /* Nonzero if '&' was found in the constraint string.  */
  66   unsigned int earlyclobber : 1;
  67   /* Nonzero if TARGET_MEM_CONSTRAINT was found in the constraint
  68      string.  */
  69   unsigned int memory_ok : 1;
  70   /* Nonzero if 'p' was found in the constraint string.  */
  71   unsigned int is_address : 1;
  72   /* Nonzero if 'X' was found in the constraint string, or if the constraint
  73      string for this alternative was empty.  */
  74   unsigned int anything_ok : 1;
  75
  76   unsigned int unused : 12;
  77 };
  78
  79 /* Return the class for operand I of alternative ALT, taking matching
  80    constraints into account.  */
  81
  82 inline enum reg_class
  83 alternative_class (const operand_alternative *alt, int i)
  84 {
  85   return alt[i].matches >= 0 ? alt[alt[i].matches].cl : alt[i].cl;
  86 }
  87
  88 /* A class for substituting one rtx for another within an instruction,
  89    or for recursively simplifying the instruction as-is.  Derived classes
  90    can record or filter certain decisions.  */
  91
  92 class insn_propagation : public simplify_context
  93 {
  94 public:
  95   /* Assignments for RESULT_FLAGS.
  96
  97      UNSIMPLIFIED is true if a substitution has been made inside an rtx
  98      X and if neither X nor its parent expressions could be simplified.
  99
 100      FIRST_SPARE_RESULT is the first flag available for derived classes.  */
 101   static const uint16_t UNSIMPLIFIED = 1U << 0;
 102   static const uint16_t FIRST_SPARE_RESULT = 1U << 1;
 103
 104   insn_propagation (rtx_insn *);
 105   insn_propagation (rtx_insn *, rtx, rtx, bool = true);
 106   bool apply_to_pattern (rtx *);
 107   bool apply_to_rvalue (rtx *);
 108
 109   /* Return true if we should accept a substitution into the address of
 110      memory expression MEM.  Undoing changes OLD_NUM_CHANGES and up restores
 111      MEM's original address.  */
 112   virtual bool check_mem (int /*old_num_changes*/,
 113                           rtx /*mem*/) { return true; }
 114
 115   /* Note that we've simplified OLD_RTX into NEW_RTX.  When substituting,
 116      this only happens if a substitution occured within OLD_RTX.
 117      Undoing OLD_NUM_CHANGES and up will restore the old form of OLD_RTX.
 118      OLD_RESULT_FLAGS is the value that RESULT_FLAGS had before processing
 119      OLD_RTX.  */
 120   virtual void note_simplification (int /*old_num_changes*/,
 121                                     uint16_t /*old_result_flags*/,
 122                                     rtx /*old_rtx*/, rtx /*new_rtx*/) {}
 123
 124 private:
 125   bool apply_to_mem_1 (rtx);
 126   bool apply_to_lvalue_1 (rtx);
 127   bool apply_to_rvalue_1 (rtx *);
 128   bool apply_to_pattern_1 (rtx *);
 129
 130 public:
 131   /* The instruction that we are simplifying or propagating into.  */
 132   rtx_insn *insn;
 133
 134   /* If FROM is nonnull, we're replacing FROM with TO, otherwise we're
 135      just doing a recursive simplification.  */
 136   rtx from;
 137   rtx to;
 138
 139   /* The number of times that we have replaced FROM with TO.  */
 140   unsigned int num_replacements;
 141
 142   /* A bitmask of flags that describe the result of the simplificiation;
 143      see above for details.  */
 144   uint16_t result_flags : 16;
 145
 146   /* True if we should unshare TO when making the next substitution,
 147      false if we can use TO itself.  */
 148   uint16_t should_unshare : 1;
 149
 150   /* True if we should call check_mem after substituting into a memory.  */
 151   uint16_t should_check_mems : 1;
 152
 153   /* True if we should call note_simplification after each simplification.  */
 154   uint16_t should_note_simplifications : 1;
 155
 156   /* For future expansion.  */
 157   uint16_t spare : 13;
 158
 159   /* Gives the reason that a substitution failed, for debug purposes.  */
 160   const char *failure_reason;
 161 };
 162
 163 /* Try to replace FROM with TO in INSN.  SHARED_P is true if TO is shared
 164    with other instructions, false if INSN can use TO directly.  */
 165
 166 inline insn_propagation::insn_propagation (rtx_insn *insn, rtx from, rtx to,
 167                                            bool shared_p)
 168   : insn (insn),
 169     from (from),
 170     to (to),
 171     num_replacements (0),
 172     result_flags (0),
 173     should_unshare (shared_p),
 174     should_check_mems (false),
 175     should_note_simplifications (false),
 176     spare (0),
 177     failure_reason (nullptr)
 178 {
 179 }
 180
 181 /* Try to simplify INSN without performing a substitution.  */
 182
 183 inline insn_propagation::insn_propagation (rtx_insn *insn)
 184   : insn_propagation (insn, NULL_RTX, NULL_RTX)
 185 {
 186 }
 187
 188 extern void init_recog (void);
 189 extern void init_recog_no_volatile (void);
 190 extern bool check_asm_operands (rtx);
 191 extern int asm_operand_ok (rtx, const char *, const char **);
 192 extern bool validate_change (rtx, rtx *, rtx, bool);
 193 extern bool validate_unshare_change (rtx, rtx *, rtx, bool);
 194 extern bool validate_change_xveclen (rtx, rtx *, int, bool);
 195 extern bool canonicalize_change_group (rtx_insn *insn, rtx x);
 196 extern bool insn_invalid_p (rtx_insn *, bool);
 197 extern bool verify_changes (int);
 198 extern void confirm_change_group (void);
 199 extern bool apply_change_group (void);
 200 extern int num_validated_changes (void);
 201 extern void cancel_changes (int);
 202 extern void temporarily_undo_changes (int);
 203 extern void redo_changes (int);
 204 extern bool constrain_operands (int, alternative_mask);
 205 extern bool constrain_operands_cached (rtx_insn *, int);
 206 extern bool memory_address_addr_space_p (machine_mode, rtx, addr_space_t,
 207                                          code_helper = ERROR_MARK);
 208 #define memory_address_p(mode,addr) \
 209         memory_address_addr_space_p ((mode), (addr), ADDR_SPACE_GENERIC)
 210 extern bool strict_memory_address_addr_space_p (machine_mode, rtx, addr_space_t,
 211                                                 code_helper = ERROR_MARK);
 212 #define strict_memory_address_p(mode,addr) \
 213         strict_memory_address_addr_space_p ((mode), (addr), ADDR_SPACE_GENERIC)
 214 extern bool validate_replace_rtx_subexp (rtx, rtx, rtx_insn *, rtx *);
 215 extern bool validate_replace_rtx (rtx, rtx, rtx_insn *);
 216 extern bool validate_replace_rtx_part (rtx, rtx, rtx *, rtx_insn *);
 217 extern bool validate_replace_rtx_part_nosimplify (rtx, rtx, rtx *, rtx_insn *);
 218 extern void validate_replace_rtx_group (rtx, rtx, rtx_insn *);
 219 extern void validate_replace_src_group (rtx, rtx, rtx_insn *);
 220 extern bool validate_simplify_insn (rtx_insn *insn);
 221 extern int num_changes_pending (void);
 222 extern bool reg_fits_class_p (const_rtx, reg_class_t, int, machine_mode);
 223 extern bool valid_insn_p (rtx_insn *);
 224
 225 extern bool offsettable_memref_p (rtx);
 226 extern bool offsettable_nonstrict_memref_p (rtx);
 227 extern bool offsettable_address_addr_space_p (int, machine_mode, rtx,
 228                                              addr_space_t);
 229 #define offsettable_address_p(strict,mode,addr) \
 230         offsettable_address_addr_space_p ((strict), (mode), (addr), \
 231                                           ADDR_SPACE_GENERIC)
 232 extern bool mode_dependent_address_p (rtx, addr_space_t);
 233
 234 extern int recog (rtx, rtx_insn *, int *);
 235 #ifndef GENERATOR_FILE
 236 inline int recog_memoized (rtx_insn *insn);
 237 #endif
 238 extern void add_clobbers (rtx, int);
 239 extern bool added_clobbers_hard_reg_p (int);
 240 extern void insn_extract (rtx_insn *);
 241 extern void extract_insn (rtx_insn *);
 242 extern void extract_constrain_insn (rtx_insn *insn);
 243 extern void extract_constrain_insn_cached (rtx_insn *);
 244 extern void extract_insn_cached (rtx_insn *);
 245 extern void preprocess_constraints (int, int, const char **,
 246                                     operand_alternative *, rtx **);
 247 extern const operand_alternative *preprocess_insn_constraints (unsigned int);
 248 extern void preprocess_constraints (rtx_insn *);
 249 extern rtx_insn *peep2_next_insn (int);
 250 extern bool peep2_regno_dead_p (int, int);
 251 extern bool peep2_reg_dead_p (int, rtx);
 252 #ifdef HARD_CONST
 253 extern rtx peep2_find_free_register (int, int, const char *,
 254                                      machine_mode, HARD_REG_SET *);
 255 #endif
 256 extern rtx_insn *peephole2_insns (rtx, rtx_insn *, int *);
 257
 258 extern bool store_data_bypass_p (rtx_insn *, rtx_insn *);
 259 extern bool if_test_bypass_p (rtx_insn *, rtx_insn *);
 260
 261 extern void copy_frame_info_to_split_insn (rtx_insn *, rtx_insn *);
 262
 263 #ifndef GENERATOR_FILE
 264 /* Try recognizing the instruction INSN,
 265    and return the code number that results.
 266    Remember the code so that repeated calls do not
 267    need to spend the time for actual rerecognition.
 268
 269    This function is the normal interface to instruction recognition.
 270    The automatically-generated function `recog' is normally called
 271    through this one.  */
 272
 273 inline int
 274 recog_memoized (rtx_insn *insn)
 275 {
 276   if (INSN_CODE (insn) < 0)
 277     INSN_CODE (insn) = recog (PATTERN (insn), insn, 0);
 278   return INSN_CODE (insn);
 279 }
 280 #endif
 281
 282 /* Skip chars until the next ',' or the end of the string.  This is
 283    useful to skip alternatives in a constraint string.  */
 284 inline const char *
 285 skip_alternative (const char *p)
 286 {
 287   const char *r = p;
 288   while (*r != '\0' && *r != ',')
 289     r++;
 290   if (*r == ',')
 291     r++;
 292   return r;
 293 }
 294
 295 /* Nonzero means volatile operands are recognized.  */
 296 extern int volatile_ok;
 297
 298 /* RAII class for temporarily setting volatile_ok.  */
 299
 300 class temporary_volatile_ok
 301 {
 302 public:
 303   temporary_volatile_ok (int value) : save_volatile_ok (volatile_ok)
 304   {
 305     volatile_ok = value;
 306   }
 307
 308   ~temporary_volatile_ok () { volatile_ok = save_volatile_ok; }
 309
 310 private:
 311   temporary_volatile_ok (const temporary_volatile_ok &);
 312   int save_volatile_ok;
 313 };
 314
 315 /* Set by constrain_operands to the number of the alternative that
 316    matched.  */
 317 extern int which_alternative;
 318
 319 /* The following vectors hold the results from insn_extract.  */
 320
 321 struct recog_data_d
 322 {
 323   /* It is very tempting to make the 5 operand related arrays into a
 324      structure and index on that.  However, to be source compatible
 325      with all of the existing md file insn constraints and output
 326      templates, we need `operand' as a flat array.  Without that
 327      member, making an array for the rest seems pointless.  */
 328
 329   /* Gives value of operand N.  */
 330   rtx operand[MAX_RECOG_OPERANDS];
 331
 332   /* Gives location where operand N was found.  */
 333   rtx *operand_loc[MAX_RECOG_OPERANDS];
 334
 335   /* Gives the constraint string for operand N.  */
 336   const char *constraints[MAX_RECOG_OPERANDS];
 337
 338   /* Nonzero if operand N is a match_operator or a match_parallel.  */
 339   char is_operator[MAX_RECOG_OPERANDS];
 340
 341   /* Gives the mode of operand N.  */
 342   machine_mode operand_mode[MAX_RECOG_OPERANDS];
 343
 344   /* Gives the type (in, out, inout) for operand N.  */
 345   enum op_type operand_type[MAX_RECOG_OPERANDS];
 346
 347   /* Gives location where the Nth duplicate-appearance of an operand
 348      was found.  This is something that matched MATCH_DUP.  */
 349   rtx *dup_loc[MAX_DUP_OPERANDS];
 350
 351   /* Gives the operand number that was duplicated in the Nth
 352      duplicate-appearance of an operand.  */
 353   char dup_num[MAX_DUP_OPERANDS];
 354
 355   /* ??? Note that these are `char' instead of `unsigned char' to (try to)
 356      avoid certain lossage from K&R C, wherein `unsigned char' default
 357      promotes to `unsigned int' instead of `int' as in ISO C.  As of 1999,
 358      the most common places to bootstrap from K&R C are SunOS and HPUX,
 359      both of which have signed characters by default.  The only other
 360      supported natives that have both K&R C and unsigned characters are
 361      ROMP and Irix 3, and neither have been seen for a while, but do
 362      continue to consider unsignedness when performing arithmetic inside
 363      a comparison.  */
 364
 365   /* The number of operands of the insn.  */
 366   char n_operands;
 367
 368   /* The number of MATCH_DUPs in the insn.  */
 369   char n_dups;
 370
 371   /* The number of alternatives in the constraints for the insn.  */
 372   char n_alternatives;
 373
 374   /* True if insn is ASM_OPERANDS.  */
 375   bool is_asm;
 376
 377   /* In case we are caching, hold insn data was generated for.  */
 378   rtx_insn *insn;
 379 };
 380
 381 extern struct recog_data_d recog_data;
 382
 383 extern const operand_alternative *recog_op_alt;
 384
 385 /* Return a pointer to an array in which index OP describes the constraints
 386    on operand OP of the current instruction alternative (which_alternative).
 387    Only valid after calling preprocess_constraints and constrain_operands.  */
 388
 389 inline const operand_alternative *
 390 which_op_alt ()
 391 {
 392   gcc_checking_assert (IN_RANGE (which_alternative, 0,
 393                                  recog_data.n_alternatives - 1));
 394   return &recog_op_alt[which_alternative * recog_data.n_operands];
 395 }
 396
 397 /* A table defined in insn-output.cc that give information about
 398    each insn-code value.  */
 399
 400 typedef bool (*insn_operand_predicate_fn) (rtx, machine_mode);
 401 typedef const char * (*insn_output_fn) (rtx *, rtx_insn *);
 402
 403 struct insn_gen_fn
 404 {
 405   typedef void (*stored_funcptr) (void);
 406
 407   template<typename ...Ts>
 408   rtx_insn *operator() (Ts... args) const
 409   {
 410     typedef rtx_insn *(*funcptr) (decltype ((void) args, NULL_RTX)...);
 411     return ((funcptr) func) (args...);
 412   }
 413
 414   // This is for compatibility of code that invokes functions like
 415   //   (*funcptr) (arg)
 416   insn_gen_fn operator * (void) const { return *this; }
 417
 418   // The wrapped function pointer must be public and there must not be any
 419   // constructors.  Otherwise the insn_data_d struct initializers generated
 420   // by genoutput.cc will result in static initializer functions, which defeats
 421   // the purpose of the generated insn_data_d array.
 422   stored_funcptr func;
 423 };
 424
 425 struct insn_operand_data
 426 {
 427   const insn_operand_predicate_fn predicate;
 428
 429   const char *const constraint;
 430
 431   ENUM_BITFIELD(machine_mode) const mode : 16;
 432
 433   const char strict_low;
 434
 435   const char is_operator;
 436
 437   const char eliminable;
 438
 439   const char allows_mem;
 440 };
 441
 442 /* Legal values for insn_data.output_format.  Indicate what type of data
 443    is stored in insn_data.output.  */
 444 #define INSN_OUTPUT_FORMAT_NONE         0       /* abort */
 445 #define INSN_OUTPUT_FORMAT_SINGLE       1       /* const char * */
 446 #define INSN_OUTPUT_FORMAT_MULTI        2       /* const char * const * */
 447 #define INSN_OUTPUT_FORMAT_FUNCTION     3       /* const char * (*)(...) */
 448
 449 struct insn_data_d
 450 {
 451   const char *const name;
 452 #if HAVE_DESIGNATED_UNION_INITIALIZERS
 453   union {
 454     const char *single;
 455     const char *const *multi;
 456     insn_output_fn function;
 457   } output;
 458 #else
 459   struct {
 460     const char *single;
 461     const char *const *multi;
 462     insn_output_fn function;
 463   } output;
 464 #endif
 465   const insn_gen_fn genfun;
 466   const struct insn_operand_data *const operand;
 467
 468   const char n_generator_args;
 469   const char n_operands;
 470   const char n_dups;
 471   const char n_alternatives;
 472   const char output_format;
 473 };
 474
 475 extern const struct insn_data_d insn_data[];
 476 extern int peep2_current_count;
 477
 478 #ifndef GENERATOR_FILE
 479 #include "insn-codes.h"
 480
 481 /* An enum of boolean attributes that may only depend on the current
 482    subtarget, not on things like operands or compiler phase.  */
 483 enum bool_attr {
 484   BA_ENABLED,
 485   BA_PREFERRED_FOR_SPEED,
 486   BA_PREFERRED_FOR_SIZE,
 487   BA_LAST = BA_PREFERRED_FOR_SIZE
 488 };
 489
 490 /* Target-dependent globals.  */
 491 struct target_recog {
 492   bool x_initialized;
 493   alternative_mask x_bool_attr_masks[NUM_INSN_CODES][BA_LAST + 1];
 494   operand_alternative *x_op_alt[NUM_INSN_CODES];
 495 };
 496
 497 extern struct target_recog default_target_recog;
 498 #if SWITCHABLE_TARGET
 499 extern struct target_recog *this_target_recog;
 500 #else
 501 #define this_target_recog (&default_target_recog)
 502 #endif
 503
 504 alternative_mask get_enabled_alternatives (rtx_insn *);
 505 alternative_mask get_preferred_alternatives (rtx_insn *);
 506 alternative_mask get_preferred_alternatives (rtx_insn *, basic_block);
 507 bool check_bool_attrs (rtx_insn *);
 508
 509 void recog_init ();
 510
 511 /* This RAII class can help to undo tentative insn changes on failure.
 512    When an object of the class goes out of scope, it undoes all group
 513    changes that have been made via the validate_change machinery and
 514    not yet confirmed via confirm_change_group.
 515
 516    For example:
 517
 518       insn_change_watermark watermark;
 519       validate_change (..., true); // A
 520       ...
 521       if (test)
 522         // Undoes change A.
 523         return false;
 524       ...
 525       validate_change (..., true); // B
 526       ...
 527       if (test)
 528         // Undoes changes A and B.
 529         return false;
 530       ...
 531       confirm_change_group ();
 532
 533    Code that wants to avoid this behavior can use keep ():
 534
 535       insn_change_watermark watermark;
 536       validate_change (..., true); // A
 537       ...
 538       if (test)
 539         // Undoes change A.
 540         return false;
 541       ...
 542       watermark.keep ();
 543       validate_change (..., true); // B
 544       ...
 545       if (test)
 546         // Undoes change B, but not A.
 547         return false;
 548       ...
 549       confirm_change_group ();  */
 550 class insn_change_watermark
 551 {
 552 public:
 553   insn_change_watermark () : m_old_num_changes (num_validated_changes ()) {}
 554   ~insn_change_watermark ();
 555   void keep () { m_old_num_changes = num_validated_changes (); }
 556
 557 private:
 558   int m_old_num_changes;
 559 };
 560
 561 inline insn_change_watermark::~insn_change_watermark ()
 562 {
 563   if (m_old_num_changes < num_validated_changes ())
 564     cancel_changes (m_old_num_changes);
 565 }
 566
 567 #endif
 568
 569 #endif /* GCC_RECOG_H */