gcc/langhooks.h

   1 /* The lang_hooks data structure.
   2    Copyright (C) 2001-2022 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
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 3, or (at your option)
   9 any later version.
  10
  11 GCC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License 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_LANG_HOOKS_H
  21 #define GCC_LANG_HOOKS_H
  22
  23 /* FIXME: This file should be #include-d after tree.h (for enum tree_code).  */
  24
  25 struct diagnostic_info;
  26
  27 struct gimplify_omp_ctx;
  28
  29 struct array_descr_info;
  30
  31 /* A print hook for print_tree ().  */
  32 typedef void (*lang_print_tree_hook) (FILE *, tree, int indent);
  33
  34 enum classify_record
  35   { RECORD_IS_STRUCT, RECORD_IS_CLASS, RECORD_IS_INTERFACE };
  36
  37 class substring_loc;
  38
  39 /* The following hooks are documented in langhooks.cc.  Must not be
  40    NULL.  */
  41
  42 struct lang_hooks_for_tree_inlining
  43 {
  44   bool (*var_mod_type_p) (tree, tree);
  45 };
  46
  47 /* The following hooks are used by tree-dump.cc.  */
  48
  49 struct lang_hooks_for_tree_dump
  50 {
  51   /* Dump language-specific parts of tree nodes.  Returns nonzero if it
  52      does not want the usual dumping of the second argument.  */
  53   bool (*dump_tree) (void *, tree);
  54
  55   /* Determine type qualifiers in a language-specific way.  */
  56   int (*type_quals) (const_tree);
  57 };
  58
  59 /* Hooks related to types.  */
  60
  61 struct lang_hooks_for_types
  62 {
  63   /* Return a new type (with the indicated CODE), doing whatever
  64      language-specific processing is required.  */
  65   tree (*make_type) (enum tree_code);
  66
  67   /* Make an enum type with the given name and values, associating
  68      them all with the given source location.  */
  69   tree (*simulate_enum_decl) (location_t, const char *, vec<string_int_pair> *);
  70
  71   /* Do the equivalent of:
  72
  73        typedef struct NAME { FIELDS; } NAME;
  74
  75      associating it with location LOC.  Return the associated RECORD_TYPE.
  76
  77      FIELDS is a list of FIELD_DECLs, in layout order.  */
  78   tree (*simulate_record_decl) (location_t loc, const char *name,
  79                                 array_slice<const tree> fields);
  80
  81   /* Return what kind of RECORD_TYPE this is, mainly for purposes of
  82      debug information.  If not defined, record types are assumed to
  83      be structures.  */
  84   enum classify_record (*classify_record) (tree);
  85
  86   /* Given MODE and UNSIGNEDP, return a suitable type-tree with that
  87      mode.  */
  88   tree (*type_for_mode) (machine_mode, int);
  89
  90   /* Given PRECISION and UNSIGNEDP, return a suitable type-tree for an
  91      integer type with at least that precision.  */
  92   tree (*type_for_size) (unsigned, int);
  93
  94   /* True if the type is an instantiation of a generic type,
  95      e.g. C++ template implicit specializations.  */
  96   bool (*generic_p) (const_tree);
  97
  98   /* Returns the TREE_VEC of elements of a given generic argument pack.  */
  99   tree (*get_argument_pack_elems) (const_tree);
 100
 101   /* Given a type, apply default promotions to unnamed function
 102      arguments and return the new type.  Return the same type if no
 103      change.  Required by any language that supports variadic
 104      arguments.  The default hook dies.  */
 105   tree (*type_promotes_to) (tree);
 106
 107   /* Register TYPE as a builtin type with the indicated NAME.  The
 108      TYPE is placed in the outermost lexical scope.  The semantics
 109      should be analogous to:
 110
 111        typedef TYPE NAME;
 112
 113      in C.  The default hook ignores the declaration.  */
 114   void (*register_builtin_type) (tree, const char *);
 115
 116   /* This routine is called in tree.cc to print an error message for
 117      invalid use of an incomplete type.  VALUE is the expression that
 118      was used (or 0 if that isn't known) and TYPE is the type that was
 119      invalid.  LOC is the location of the use.  */
 120   void (*incomplete_type_error) (location_t loc, const_tree value,
 121                                  const_tree type);
 122
 123   /* Called from assign_temp to return the maximum size, if there is one,
 124      for a type.  */
 125   tree (*max_size) (const_tree);
 126
 127   /* Register language specific type size variables as potentially OpenMP
 128      firstprivate variables.  */
 129   void (*omp_firstprivatize_type_sizes) (struct gimplify_omp_ctx *, tree);
 130
 131   /* Return true if TYPE is a mappable type.  */
 132   bool (*omp_mappable_type) (tree type);
 133
 134   /* Return TRUE if TYPE1 and TYPE2 are identical for type hashing purposes.
 135      Called only after doing all language independent checks.
 136      At present, this function is only called when both TYPE1 and TYPE2 are
 137      FUNCTION_TYPE or METHOD_TYPE.  */
 138   bool (*type_hash_eq) (const_tree, const_tree);
 139
 140   /* If non-NULL, return TYPE1 with any language-specific modifiers copied from
 141      TYPE2.  */
 142   tree (*copy_lang_qualifiers) (const_tree, const_tree);
 143
 144   /* Return TRUE if TYPE uses a hidden descriptor and fills in information
 145      for the debugger about the array bounds, strides, etc.  */
 146   bool (*get_array_descr_info) (const_tree, struct array_descr_info *);
 147
 148   /* Fill in information for the debugger about the bounds of TYPE.  */
 149   void (*get_subrange_bounds) (const_tree, tree *, tree *);
 150
 151   /* Called on INTEGER_TYPEs.  Return NULL_TREE for non-biased types.  For
 152      biased types, return as an INTEGER_CST node the value that is represented
 153      by a physical zero.  */
 154   tree (*get_type_bias) (const_tree);
 155
 156   /* A type descriptive of TYPE's complex layout generated to help the
 157      debugger to decode variable-length or self-referential constructs.
 158      This is only used for the AT_GNAT_descriptive_type DWARF attribute.  */
 159   tree (*descriptive_type) (const_tree);
 160
 161   /* If we requested a pointer to a vector, build up the pointers that
 162      we stripped off while looking for the inner type.  Similarly for
 163      return values from functions.  The argument TYPE is the top of the
 164      chain, and BOTTOM is the new type which we will point to.  */
 165   tree (*reconstruct_complex_type) (tree, tree);
 166
 167   /* Returns the tree that represents the underlying data type used to
 168      implement the enumeration.  The default implementation will just use
 169      type_for_size.  Used in dwarf2out.cc to add a DW_AT_type base type
 170      reference to a DW_TAG_enumeration.  */
 171   tree (*enum_underlying_base_type) (const_tree);
 172
 173   /* Return a type to use in the debug info instead of TYPE, or NULL_TREE to
 174      keep TYPE.  This is useful to keep a single "source type" when the
 175      middle-end uses specialized types, for instance constrained discriminated
 176      types in Ada.  */
 177   tree (*get_debug_type) (const_tree);
 178
 179   /* Return TRUE if TYPE implements a fixed point type and fills in information
 180      for the debugger about scale factor, etc.  */
 181   bool (*get_fixed_point_type_info) (const_tree,
 182                                      struct fixed_point_type_info *);
 183
 184   /* Returns -1 if dwarf ATTR shouldn't be added for TYPE, or the attribute
 185      value otherwise.  */
 186   int (*type_dwarf_attribute) (const_tree, int);
 187
 188   /* Returns a tree for the unit size of T excluding tail padding that
 189      might be used by objects inheriting from T.  */
 190   tree (*unit_size_without_reusable_padding) (tree);
 191
 192   /* Returns type corresponding to FIELD's type when FIELD is a C++ base class
 193      i.e., type without virtual base classes or tail padding.  Returns
 194      NULL_TREE otherwise.  */
 195   tree (*classtype_as_base) (const_tree);
 196 };
 197
 198 /* Language hooks related to decls and the symbol table.  */
 199
 200 struct lang_hooks_for_decls
 201 {
 202   /* Return true if we are in the global binding level.  This hook is really
 203      needed only if the language supports variable-sized types at the global
 204      level, i.e. declared outside subprograms.  */
 205   bool (*global_bindings_p) (void);
 206
 207   /* Function to add a decl to the current scope level.  Takes one
 208      argument, a decl to add.  Returns that decl, or, if the same
 209      symbol is already declared, may return a different decl for that
 210      name.  */
 211   tree (*pushdecl) (tree);
 212
 213   /* Returns the chain of decls so far in the current scope level.  */
 214   tree (*getdecls) (void);
 215
 216   /* Returns -1 if dwarf ATTR shouldn't be added for DECL, or the attribute
 217      value otherwise.  */
 218   int (*decl_dwarf_attribute) (const_tree, int);
 219
 220   /* Returns True if the parameter is a generic parameter decl
 221      of a generic type, e.g a template template parameter for the C++ FE.  */
 222   bool (*generic_generic_parameter_decl_p) (const_tree);
 223
 224   /* Determine if a function parameter got expanded from a
 225      function parameter pack.  */
 226   bool (*function_parm_expanded_from_pack_p) (tree, tree);
 227
 228   /* Returns the generic declaration of a generic function instantiations.  */
 229   tree (*get_generic_function_decl) (const_tree);
 230
 231   /* Returns true when we should warn for an unused global DECL.
 232      We will already have checked that it has static binding.  */
 233   bool (*warn_unused_global) (const_tree);
 234
 235   /* Perform any post compilation-proper parser cleanups and
 236      processing.  This is currently only needed for the C++ parser,
 237      which hopefully can be cleaned up so this hook is no longer
 238      necessary.  */
 239   void (*post_compilation_parsing_cleanups) (void);
 240
 241   /* True if this decl may be called via a sibcall.  */
 242   bool (*ok_for_sibcall) (const_tree);
 243
 244   /* Return a tree for the actual data of an array descriptor - or NULL_TREE
 245      if original tree is not an array descriptor.  If the second argument
 246      is true, only the TREE_TYPE is returned without generating a new tree.  */
 247   tree (*omp_array_data) (tree, bool);
 248
 249   /* Return a tree for the actual data of an array descriptor - or NULL_TREE
 250      if original tree is not an array descriptor.  If the second argument
 251      is true, only the TREE_TYPE is returned without generating a new tree.  */
 252   tree (*omp_array_size) (tree, gimple_seq *pre_p);
 253
 254   /* True if OpenMP should regard this DECL as being a scalar which has Fortran's
 255      allocatable or pointer attribute.  */
 256   bool (*omp_is_allocatable_or_ptr) (const_tree);
 257
 258   /* Check whether this DECL belongs to a Fortran optional argument.
 259      With 'for_present_check' set to false, decls which are optional parameters
 260      themselve are returned as tree - or a NULL_TREE otherwise. Those decls are
 261      always pointers.  With 'for_present_check' set to true, the decl for
 262      checking whether an argument is present is returned; for arguments with
 263      value attribute this is the hidden argument and of BOOLEAN_TYPE.  If the
 264      decl is unrelated to optional arguments, NULL_TREE is returned.  */
 265   tree (*omp_check_optional_argument) (tree, bool);
 266
 267   /* True if OpenMP should privatize what this DECL points to rather
 268      than the DECL itself.  */
 269   bool (*omp_privatize_by_reference) (const_tree);
 270
 271   /* Return sharing kind if OpenMP sharing attribute of DECL is
 272      predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 273   enum omp_clause_default_kind (*omp_predetermined_sharing) (tree);
 274
 275   /* Return mapping kind if OpenMP mapping attribute of DECL is
 276      predetermined, OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED otherwise.  */
 277   enum omp_clause_defaultmap_kind (*omp_predetermined_mapping) (tree);
 278
 279   /* Return decl that should be reported for DEFAULT(NONE) failure
 280      diagnostics.  Usually the DECL passed in.  */
 281   tree (*omp_report_decl) (tree);
 282
 283   /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
 284      disregarded in OpenMP construct, because it is going to be
 285      remapped during OpenMP lowering.  SHARED is true if DECL
 286      is going to be shared, false if it is going to be privatized.  */
 287   bool (*omp_disregard_value_expr) (tree, bool);
 288
 289   /* Return true if DECL that is shared iff SHARED is true should
 290      be put into OMP_CLAUSE_PRIVATE_DEBUG.  */
 291   bool (*omp_private_debug_clause) (tree, bool);
 292
 293   /* Return true if DECL in private clause needs
 294      OMP_CLAUSE_PRIVATE_OUTER_REF on the private clause.  */
 295   bool (*omp_private_outer_ref) (tree);
 296
 297   /* Build and return code for a default constructor for DECL in
 298      response to CLAUSE.  OUTER is corresponding outer region's
 299      variable if needed.  Return NULL if nothing to be done.  */
 300   tree (*omp_clause_default_ctor) (tree clause, tree decl, tree outer);
 301
 302   /* Build and return code for a copy constructor from SRC to DST.  */
 303   tree (*omp_clause_copy_ctor) (tree clause, tree dst, tree src);
 304
 305   /* Similarly, except use an assignment operator instead.  */
 306   tree (*omp_clause_assign_op) (tree clause, tree dst, tree src);
 307
 308   /* Build and return code for a constructor of DST that sets it to
 309      SRC + ADD.  */
 310   tree (*omp_clause_linear_ctor) (tree clause, tree dst, tree src, tree add);
 311
 312   /* Build and return code destructing DECL.  Return NULL if nothing
 313      to be done.  */
 314   tree (*omp_clause_dtor) (tree clause, tree decl);
 315
 316   /* Do language specific checking on an implicitly determined clause.  */
 317   void (*omp_finish_clause) (tree clause, gimple_seq *pre_p, bool);
 318
 319   /* Return true if DECL is an allocatable variable (for the purpose of
 320      implicit mapping).  */
 321   bool (*omp_allocatable_p) (tree decl);
 322
 323   /* Return true if DECL is a scalar variable (for the purpose of
 324      implicit firstprivatization). If 'ptr_or', pointers and
 325      allocatables are also permitted.  */
 326   bool (*omp_scalar_p) (tree decl, bool ptr_ok);
 327
 328   /* Return true if DECL is a scalar variable with Fortran target but not
 329      allocatable or pointer attribute (for the purpose of implicit mapping).  */
 330   bool (*omp_scalar_target_p) (tree decl);
 331
 332   /* Return a pointer to the tree representing the initializer
 333      expression for the non-local variable DECL.  Return NULL if
 334      DECL is not initialized.  */
 335   tree *(*omp_get_decl_init) (tree decl);
 336
 337   /* Free any extra memory used to hold initializer information for
 338      variable declarations.  omp_get_decl_init must not be called
 339      after calling this.  */
 340   void (*omp_finish_decl_inits) (void);
 341 };
 342
 343 /* Language hooks related to LTO serialization.  */
 344
 345 struct lang_hooks_for_lto
 346 {
 347   /* Begin a new LTO section named NAME.  */
 348   void (*begin_section) (const char *name);
 349
 350   /* Write DATA of length LEN to the currently open LTO section.  BLOCK is a
 351      pointer to the dynamically allocated memory containing DATA.  The
 352      append_data function is responsible for freeing it when it is no longer
 353      needed.  */
 354   void (*append_data) (const void *data, size_t len, void *block);
 355
 356   /* End the previously begun LTO section.  */
 357   void (*end_section) (void);
 358 };
 359
 360 /* Language-specific hooks.  See langhooks-def.h for defaults.  */
 361
 362 struct lang_hooks
 363 {
 364   /* String identifying the front end and optionally language standard
 365      version, e.g. "GNU C++98".  */
 366   const char *name;
 367
 368   /* sizeof (struct lang_identifier), so make_node () creates
 369      identifier nodes long enough for the language-specific slots.  */
 370   size_t identifier_size;
 371
 372   /* Remove any parts of the tree that are used only by the FE. */
 373   void (*free_lang_data) (tree);
 374
 375   /* Determines the size of any language-specific tcc_constant,
 376      tcc_exceptional or tcc_type nodes.  Since it is called from
 377      make_node, the only information available is the tree code.
 378      Expected to die on unrecognized codes.  */
 379   size_t (*tree_size) (enum tree_code);
 380
 381   /* Return the language mask used for converting argv into a sequence
 382      of options.  */
 383   unsigned int (*option_lang_mask) (void);
 384
 385   /* Initialize variables in an options structure.  */
 386   void (*init_options_struct) (struct gcc_options *opts);
 387
 388   /* After the initialize_diagnostics hook is called, do any simple
 389      initialization needed before any calls to handle_option, other
 390      than that done by the init_options_struct hook.  */
 391   void (*init_options) (unsigned int decoded_options_count,
 392                         struct cl_decoded_option *decoded_options);
 393
 394   /* Callback used to perform language-specific initialization for the
 395      global diagnostic context structure.  */
 396   void (*initialize_diagnostics) (diagnostic_context *);
 397
 398   /* Beginning the main source file.  */
 399   void (*preprocess_main_file) (cpp_reader *, line_maps *,
 400                                 const line_map_ordinary *);
 401
 402   /* Adjust libcpp options and callbacks.  */
 403   void (*preprocess_options) (cpp_reader *);
 404
 405   /* Undefining a macro.  */
 406   void (*preprocess_undef) (cpp_reader *, location_t, cpp_hashnode *);
 407
 408   /* Observer for preprocessing stream.  */
 409   uintptr_t (*preprocess_token) (cpp_reader *, const cpp_token *, uintptr_t);
 410   /* Various flags it can return about the token.  */
 411   enum PT_flags
 412     {
 413      PT_begin_pragma = 1 << 0
 414     };
 415
 416   /* Register language-specific dumps.  */
 417   void (*register_dumps) (gcc::dump_manager *);
 418
 419   /* Return true if a warning should be given about option OPTION,
 420      which is for the wrong language, false if it should be quietly
 421      ignored.  */
 422   bool (*complain_wrong_lang_p) (const struct cl_option *option);
 423
 424   /* Handle the switch CODE, which has real type enum opt_code from
 425      options.h.  If the switch takes an argument, it is passed in ARG
 426      which points to permanent storage.  The handler is responsible for
 427      checking whether ARG is NULL, which indicates that no argument
 428      was in fact supplied.  For -f and -W switches, VALUE is 1 or 0
 429      for the positive and negative forms respectively.  HANDLERS should
 430      be passed to any recursive handle_option calls.  LOC is the
 431      location of the option.
 432
 433      Return true if the switch is valid, false if invalid.  */
 434   bool (*handle_option) (size_t code, const char *arg, HOST_WIDE_INT value,
 435                          int kind, location_t loc,
 436                          const struct cl_option_handlers *handlers);
 437
 438   /* Called when all command line options have been parsed to allow
 439      further processing and initialization
 440
 441      Should return true to indicate that a compiler back-end is
 442      not required, such as with the -E option.
 443
 444      If errorcount is nonzero after this call the compiler exits
 445      immediately and the finish hook is not called.  */
 446   bool (*post_options) (const char **);
 447
 448   /* Called after post_options to initialize the front end.  Return
 449      false to indicate that no further compilation be performed, in
 450      which case the finish hook is called immediately.  */
 451   bool (*init) (void);
 452
 453   /* Called at the end of compilation, as a finalizer.  */
 454   void (*finish) (void);
 455
 456   /* Parses the entire file.  */
 457   void (*parse_file) (void);
 458
 459   /* Determines if it's ok for a function to have no noreturn attribute.  */
 460   bool (*missing_noreturn_ok_p) (tree);
 461
 462   /* Called to obtain the alias set to be used for an expression or type.
 463      Returns -1 if the language does nothing special for it.  */
 464   alias_set_type (*get_alias_set) (tree);
 465
 466   /* Function to finish handling an incomplete decl at the end of
 467      compilation.  Default hook is does nothing.  */
 468   void (*finish_incomplete_decl) (tree);
 469
 470   /* Replace the DECL_LANG_SPECIFIC data, which may be NULL, of the
 471      DECL_NODE with a newly GC-allocated copy.  */
 472   void (*dup_lang_specific_decl) (tree);
 473
 474   /* Set the DECL_ASSEMBLER_NAME for a node.  If it is the sort of
 475      thing that the assembler should talk about, set
 476      DECL_ASSEMBLER_NAME to an appropriate IDENTIFIER_NODE.
 477      Otherwise, set it to the ERROR_MARK_NODE to ensure that the
 478      assembler does not talk about it.  */
 479   void (*set_decl_assembler_name) (tree);
 480
 481   /* Overwrite the DECL_ASSEMBLER_NAME for a node.  The name is being
 482      changed (including to or from NULL_TREE).  */
 483   void (*overwrite_decl_assembler_name) (tree, tree);
 484
 485   /* The front end can add its own statistics to -fmem-report with
 486      this hook.  It should output to stderr.  */
 487   void (*print_statistics) (void);
 488
 489   /* Called by print_tree when there is a tree of class tcc_exceptional
 490      or tcc_constant that it doesn't know how to display.  */
 491   lang_print_tree_hook print_xnode;
 492
 493   /* Called to print language-dependent parts of tcc_decl, tcc_type,
 494      and IDENTIFIER_NODE nodes.  */
 495   lang_print_tree_hook print_decl;
 496   lang_print_tree_hook print_type;
 497   lang_print_tree_hook print_identifier;
 498
 499   /* Computes the name to use to print a declaration.  DECL is the
 500      non-NULL declaration in question.  VERBOSITY determines what
 501      information will be printed: 0: DECL_NAME, demangled as
 502      necessary.  1: and scope information.  2: and any other
 503      information that might be interesting, such as function parameter
 504      types in C++.  The name is in the internal character set and
 505      needs to be converted to the locale character set of diagnostics,
 506      or to the execution character set for strings such as
 507      __PRETTY_FUNCTION__.  */
 508   const char *(*decl_printable_name) (tree decl, int verbosity);
 509
 510   /* Computes the dwarf-2/3 name for a tree.  VERBOSITY determines what
 511      information will be printed: 0: DECL_NAME, demangled as
 512      necessary.  1: and scope information.  */
 513   const char *(*dwarf_name) (tree, int verbosity);
 514
 515   /* This compares two types for equivalence ("compatible" in C-based languages).
 516      This routine should only return 1 if it is sure.  It should not be used
 517      in contexts where erroneously returning 0 causes problems.  */
 518   int (*types_compatible_p) (tree x, tree y);
 519
 520   /* Called by report_error_function to print out function name.  */
 521   void (*print_error_function) (diagnostic_context *, const char *,
 522                                 struct diagnostic_info *);
 523
 524   /* Convert a character from the host's to the target's character
 525      set.  The character should be in what C calls the "basic source
 526      character set" (roughly, the set of characters defined by plain
 527      old ASCII).  The default is to return the character unchanged,
 528      which is correct in most circumstances.  Note that both argument
 529      and result should be sign-extended under -fsigned-char,
 530      zero-extended under -fno-signed-char.  */
 531   HOST_WIDE_INT (*to_target_charset) (HOST_WIDE_INT);
 532
 533   /* Pointers to machine-independent attribute tables, for front ends
 534      using attribs.cc.  If one is NULL, it is ignored.  Respectively, a
 535      table of attributes specific to the language, a table of
 536      attributes common to two or more languages (to allow easy
 537      sharing), and a table of attributes for checking formats.  */
 538   const struct attribute_spec *attribute_table;
 539   const struct attribute_spec *common_attribute_table;
 540   const struct attribute_spec *format_attribute_table;
 541
 542   struct lang_hooks_for_tree_inlining tree_inlining;
 543
 544   struct lang_hooks_for_tree_dump tree_dump;
 545
 546   struct lang_hooks_for_decls decls;
 547
 548   struct lang_hooks_for_types types;
 549
 550   struct lang_hooks_for_lto lto;
 551
 552   /* Returns a TREE_VEC of the generic parameters of an instantiation of
 553      a generic type or decl, e.g. C++ template instantiation.  If
 554      TREE_CHAIN of the return value is set, it is an INTEGER_CST
 555      indicating how many of the elements are non-default.  */
 556   tree (*get_innermost_generic_parms) (const_tree);
 557
 558   /* Returns the TREE_VEC of arguments of an instantiation
 559      of a generic type of decl, e.g. C++ template instantiation.  */
 560   tree (*get_innermost_generic_args) (const_tree);
 561
 562   /* Determine if a tree is a function parameter pack.  */
 563   bool (*function_parameter_pack_p) (const_tree);
 564
 565   /* Perform language-specific gimplification on the argument.  Returns an
 566      enum gimplify_status, though we can't see that type here.  */
 567   int (*gimplify_expr) (tree *, gimple_seq *, gimple_seq *);
 568
 569   /* Do language specific processing in the builtin function DECL  */
 570   tree (*builtin_function) (tree decl);
 571
 572   /* Like builtin_function, but make sure the scope is the external scope.
 573      This is used to delay putting in back end builtin functions until the ISA
 574      that defines the builtin is declared via function specific target options,
 575      which can save memory for machines like the x86_64 that have multiple
 576      ISAs.  If this points to the same function as builtin_function, the
 577      backend must add all of the builtins at program initialization time.  */
 578   tree (*builtin_function_ext_scope) (tree decl);
 579
 580   /* Do language-specific processing for target-specific built-in
 581      function DECL, so that it is defined in the global scope (only)
 582      and is available without needing to be explicitly declared.
 583
 584      This is intended for targets that want to inject declarations of
 585      built-in functions into the source language (such as in response
 586      to a pragma) rather than providing them in the source language itself.  */
 587   tree (*simulate_builtin_function_decl) (tree decl);
 588
 589   /* Used to set up the tree_contains_structure array for a frontend. */
 590   void (*init_ts) (void);
 591
 592   /* Called by recompute_tree_invariant_for_addr_expr to go from EXPR
 593      to a contained expression or DECL, possibly updating *TC or *SE
 594      if in the process TREE_CONSTANT or TREE_SIDE_EFFECTS need updating.  */
 595   tree (*expr_to_decl) (tree expr, bool *tc, bool *se);
 596
 597   /* The EH personality function decl.  */
 598   tree (*eh_personality) (void);
 599
 600   /* Map a type to a runtime object to match type.  */
 601   tree (*eh_runtime_type) (tree);
 602
 603   /* If non-NULL, this is a function that returns a function decl to be
 604      executed if an unhandled exception is propagated out of a cleanup
 605      region.  For example, in C++, an exception thrown by a destructor
 606      during stack unwinding is required to result in a call to
 607      `std::terminate', so the C++ version of this function returns a
 608      FUNCTION_DECL for `std::terminate'.  */
 609   tree (*eh_protect_cleanup_actions) (void);
 610
 611   /* Return true if a stmt can fallthru.  Used by block_may_fallthru
 612      to possibly handle language trees.  */
 613   bool (*block_may_fallthru) (const_tree);
 614
 615   /* True if this language uses __cxa_end_cleanup when the ARM EABI
 616      is enabled.  */
 617   bool eh_use_cxa_end_cleanup;
 618
 619   /* True if this language requires deep unsharing of tree nodes prior to
 620      gimplification.  */
 621   bool deep_unsharing;
 622
 623   /* True if this language may use custom descriptors for nested functions
 624      instead of trampolines.  */
 625   bool custom_function_descriptors;
 626
 627   /* True if this language emits begin stmt notes.  */
 628   bool emits_begin_stmt;
 629
 630   /* Run all lang-specific selftests.  */
 631   void (*run_lang_selftests) (void);
 632
 633   /* Attempt to determine the source location of the substring.
 634      If successful, return NULL and write the source location to *OUT_LOC.
 635      Otherwise return an error message.  Error messages are intended
 636      for GCC developers (to help debugging) rather than for end-users.  */
 637   const char *(*get_substring_location) (const substring_loc &,
 638                                          location_t *out_loc);
 639
 640   /* Invoked before the early_finish debug hook is invoked.  */
 641   void (*finalize_early_debug) (void);
 642
 643   /* Get a value for the SARIF v2.1.0 "artifact.sourceLanguage" property
 644      for FILENAME, or return NULL.
 645      See SARIF v2.1.0 Appendix J for suggested values for common programming
 646      languages.  */
 647   const char *(*get_sarif_source_language) (const char *filename);
 648
 649   /* Whenever you add entries here, make sure you adjust langhooks-def.h
 650      and langhooks.cc accordingly.  */
 651 };
 652
 653 /* Each front end provides its own.  */
 654 extern struct lang_hooks lang_hooks;
 655
 656 extern tree add_builtin_function (const char *name, tree type,
 657                                   int function_code, enum built_in_class cl,
 658                                   const char *library_name,
 659                                   tree attrs);
 660
 661 extern tree add_builtin_function_ext_scope (const char *name, tree type,
 662                                             int function_code,
 663                                             enum built_in_class cl,
 664                                             const char *library_name,
 665                                             tree attrs);
 666 extern tree simulate_builtin_function_decl (location_t, const char *, tree,
 667                                             int, const char *, tree);
 668 extern tree add_builtin_type (const char *name, tree type);
 669
 670 /* Language helper functions.  */
 671
 672 extern bool lang_GNU_C (void);
 673 extern bool lang_GNU_CXX (void);
 674 extern bool lang_GNU_Fortran (void);
 675 extern bool lang_GNU_OBJC (void);
 676
 677 #endif /* GCC_LANG_HOOKS_H */