gcc/langhooks.h

   1 /* The lang_hooks data structure.
   2    Copyright (C) 2001-2023 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
   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 TYPE1 and TYPE2 are identical for type hashing purposes.
 132      Called only after doing all language independent checks.
 133      At present, this function is only called when both TYPE1 and TYPE2 are
 134      FUNCTION_TYPE or METHOD_TYPE.  */
 135   bool (*type_hash_eq) (const_tree, const_tree);
 136
 137   /* If non-NULL, return TYPE1 with any language-specific modifiers copied from
 138      TYPE2.  */
 139   tree (*copy_lang_qualifiers) (const_tree, const_tree);
 140
 141   /* Return TRUE if TYPE uses a hidden descriptor and fills in information
 142      for the debugger about the array bounds, strides, etc.  */
 143   bool (*get_array_descr_info) (const_tree, struct array_descr_info *);
 144
 145   /* Fill in information for the debugger about the bounds of TYPE.  */
 146   void (*get_subrange_bounds) (const_tree, tree *, tree *);
 147
 148   /* Called on INTEGER_TYPEs.  Return NULL_TREE for non-biased types.  For
 149      biased types, return as an INTEGER_CST node the value that is represented
 150      by a physical zero.  */
 151   tree (*get_type_bias) (const_tree);
 152
 153   /* A type descriptive of TYPE's complex layout generated to help the
 154      debugger to decode variable-length or self-referential constructs.
 155      This is only used for the AT_GNAT_descriptive_type DWARF attribute.  */
 156   tree (*descriptive_type) (const_tree);
 157
 158   /* If we requested a pointer to a vector, build up the pointers that
 159      we stripped off while looking for the inner type.  Similarly for
 160      return values from functions.  The argument TYPE is the top of the
 161      chain, and BOTTOM is the new type which we will point to.  */
 162   tree (*reconstruct_complex_type) (tree, tree);
 163
 164   /* Returns the tree that represents the underlying data type used to
 165      implement the enumeration.  The default implementation will just use
 166      type_for_size.  Used in dwarf2out.cc to add a DW_AT_type base type
 167      reference to a DW_TAG_enumeration.  */
 168   tree (*enum_underlying_base_type) (const_tree);
 169
 170   /* Return a type to use in the debug info instead of TYPE, or NULL_TREE to
 171      keep TYPE.  This is useful to keep a single "source type" when the
 172      middle-end uses specialized types, for instance constrained discriminated
 173      types in Ada.  */
 174   tree (*get_debug_type) (const_tree);
 175
 176   /* Return TRUE if TYPE implements a fixed point type and fills in information
 177      for the debugger about scale factor, etc.  */
 178   bool (*get_fixed_point_type_info) (const_tree,
 179                                      struct fixed_point_type_info *);
 180
 181   /* Returns -1 if dwarf ATTR shouldn't be added for TYPE, or the attribute
 182      value otherwise.  */
 183   int (*type_dwarf_attribute) (const_tree, int);
 184
 185   /* Returns a tree for the unit size of T excluding tail padding that
 186      might be used by objects inheriting from T.  */
 187   tree (*unit_size_without_reusable_padding) (tree);
 188
 189   /* Returns type corresponding to FIELD's type when FIELD is a C++ base class
 190      i.e., type without virtual base classes or tail padding.  Returns
 191      NULL_TREE otherwise.  */
 192   tree (*classtype_as_base) (const_tree);
 193 };
 194
 195 /* Language hooks related to decls and the symbol table.  */
 196
 197 struct lang_hooks_for_decls
 198 {
 199   /* Return true if we are in the global binding level.  This hook is really
 200      needed only if the language supports variable-sized types at the global
 201      level, i.e. declared outside subprograms.  */
 202   bool (*global_bindings_p) (void);
 203
 204   /* Function to add a decl to the current scope level.  Takes one
 205      argument, a decl to add.  Returns that decl, or, if the same
 206      symbol is already declared, may return a different decl for that
 207      name.  */
 208   tree (*pushdecl) (tree);
 209
 210   /* Returns the chain of decls so far in the current scope level.  */
 211   tree (*getdecls) (void);
 212
 213   /* Returns -1 if dwarf ATTR shouldn't be added for DECL, or the attribute
 214      value otherwise.  */
 215   int (*decl_dwarf_attribute) (const_tree, int);
 216
 217   /* Returns True if the parameter is a generic parameter decl
 218      of a generic type, e.g a template template parameter for the C++ FE.  */
 219   bool (*generic_generic_parameter_decl_p) (const_tree);
 220
 221   /* Determine if a function parameter got expanded from a
 222      function parameter pack.  */
 223   bool (*function_parm_expanded_from_pack_p) (tree, tree);
 224
 225   /* Returns the generic declaration of a generic function instantiations.  */
 226   tree (*get_generic_function_decl) (const_tree);
 227
 228   /* Returns true when we should warn for an unused global DECL.
 229      We will already have checked that it has static binding.  */
 230   bool (*warn_unused_global) (const_tree);
 231
 232   /* Perform any post compilation-proper parser cleanups and
 233      processing.  This is currently only needed for the C++ parser,
 234      which hopefully can be cleaned up so this hook is no longer
 235      necessary.  */
 236   void (*post_compilation_parsing_cleanups) (void);
 237
 238   /* True if this decl may be called via a sibcall.  */
 239   bool (*ok_for_sibcall) (const_tree);
 240
 241   /* Return a tree for the actual data of an array descriptor - or NULL_TREE
 242      if original tree is not an array descriptor.  If the second argument
 243      is true, only the TREE_TYPE is returned without generating a new tree.  */
 244   tree (*omp_array_data) (tree, bool);
 245
 246   /* Return a tree for the actual data of an array descriptor - or NULL_TREE
 247      if original tree is not an array descriptor.  If the second argument
 248      is true, only the TREE_TYPE is returned without generating a new tree.  */
 249   tree (*omp_array_size) (tree, gimple_seq *pre_p);
 250
 251   /* True if OpenMP should regard this DECL as being a scalar which has Fortran's
 252      allocatable or pointer attribute.  */
 253   bool (*omp_is_allocatable_or_ptr) (const_tree);
 254
 255   /* Check whether this DECL belongs to a Fortran optional argument.
 256      With 'for_present_check' set to false, decls which are optional parameters
 257      themselve are returned as tree - or a NULL_TREE otherwise. Those decls are
 258      always pointers.  With 'for_present_check' set to true, the decl for
 259      checking whether an argument is present is returned; for arguments with
 260      value attribute this is the hidden argument and of BOOLEAN_TYPE.  If the
 261      decl is unrelated to optional arguments, NULL_TREE is returned.  */
 262   tree (*omp_check_optional_argument) (tree, bool);
 263
 264   /* True if OpenMP should privatize what this DECL points to rather
 265      than the DECL itself.  */
 266   bool (*omp_privatize_by_reference) (const_tree);
 267
 268   /* Return sharing kind if OpenMP sharing attribute of DECL is
 269      predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 270   enum omp_clause_default_kind (*omp_predetermined_sharing) (tree);
 271
 272   /* Return mapping kind if OpenMP mapping attribute of DECL is
 273      predetermined, OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED otherwise.  */
 274   enum omp_clause_defaultmap_kind (*omp_predetermined_mapping) (tree);
 275
 276   /* Return decl that should be reported for DEFAULT(NONE) failure
 277      diagnostics.  Usually the DECL passed in.  */
 278   tree (*omp_report_decl) (tree);
 279
 280   /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
 281      disregarded in OpenMP construct, because it is going to be
 282      remapped during OpenMP lowering.  SHARED is true if DECL
 283      is going to be shared, false if it is going to be privatized.  */
 284   bool (*omp_disregard_value_expr) (tree, bool);
 285
 286   /* Return true if DECL that is shared iff SHARED is true should
 287      be put into OMP_CLAUSE_PRIVATE_DEBUG.  */
 288   bool (*omp_private_debug_clause) (tree, bool);
 289
 290   /* Return true if DECL in private clause needs
 291      OMP_CLAUSE_PRIVATE_OUTER_REF on the private clause.  */
 292   bool (*omp_private_outer_ref) (tree);
 293
 294   /* Build and return code for a default constructor for DECL in
 295      response to CLAUSE.  OUTER is corresponding outer region's
 296      variable if needed.  Return NULL if nothing to be done.  */
 297   tree (*omp_clause_default_ctor) (tree clause, tree decl, tree outer);
 298
 299   /* Build and return code for a copy constructor from SRC to DST.  */
 300   tree (*omp_clause_copy_ctor) (tree clause, tree dst, tree src);
 301
 302   /* Similarly, except use an assignment operator instead.  */
 303   tree (*omp_clause_assign_op) (tree clause, tree dst, tree src);
 304
 305   /* Build and return code for a constructor of DST that sets it to
 306      SRC + ADD.  */
 307   tree (*omp_clause_linear_ctor) (tree clause, tree dst, tree src, tree add);
 308
 309   /* Build and return code destructing DECL.  Return NULL if nothing
 310      to be done.  */
 311   tree (*omp_clause_dtor) (tree clause, tree decl);
 312
 313   /* Do language specific checking on an implicitly determined clause.  */
 314   void (*omp_finish_clause) (tree clause, gimple_seq *pre_p, bool);
 315
 316   /* Return true if DECL is an allocatable variable (for the purpose of
 317      implicit mapping).  */
 318   bool (*omp_allocatable_p) (tree decl);
 319
 320   /* Return true if DECL is a scalar variable (for the purpose of
 321      implicit firstprivatization). If 'ptr_or', pointers and
 322      allocatables are also permitted.  */
 323   bool (*omp_scalar_p) (tree decl, bool ptr_ok);
 324
 325   /* Return true if DECL is a scalar variable with Fortran target but not
 326      allocatable or pointer attribute (for the purpose of implicit mapping).  */
 327   bool (*omp_scalar_target_p) (tree decl);
 328
 329   /* Return a pointer to the tree representing the initializer
 330      expression for the non-local variable DECL.  Return NULL if
 331      DECL is not initialized.  */
 332   tree *(*omp_get_decl_init) (tree decl);
 333
 334   /* Free any extra memory used to hold initializer information for
 335      variable declarations.  omp_get_decl_init must not be called
 336      after calling this.  */
 337   void (*omp_finish_decl_inits) (void);
 338 };
 339
 340 /* Language hooks related to LTO serialization.  */
 341
 342 struct lang_hooks_for_lto
 343 {
 344   /* Begin a new LTO section named NAME.  */
 345   void (*begin_section) (const char *name);
 346
 347   /* Write DATA of length LEN to the currently open LTO section.  BLOCK is a
 348      pointer to the dynamically allocated memory containing DATA.  The
 349      append_data function is responsible for freeing it when it is no longer
 350      needed.  */
 351   void (*append_data) (const void *data, size_t len, void *block);
 352
 353   /* End the previously begun LTO section.  */
 354   void (*end_section) (void);
 355 };
 356
 357 /* Language-specific hooks.  See langhooks-def.h for defaults.  */
 358
 359 struct lang_hooks
 360 {
 361   /* String identifying the front end and optionally language standard
 362      version, e.g. "GNU C++98".  */
 363   const char *name;
 364
 365   /* sizeof (struct lang_identifier), so make_node () creates
 366      identifier nodes long enough for the language-specific slots.  */
 367   size_t identifier_size;
 368
 369   /* Remove any parts of the tree that are used only by the FE. */
 370   void (*free_lang_data) (tree);
 371
 372   /* Determines the size of any language-specific tcc_constant,
 373      tcc_exceptional or tcc_type nodes.  Since it is called from
 374      make_node, the only information available is the tree code.
 375      Expected to die on unrecognized codes.  */
 376   size_t (*tree_size) (enum tree_code);
 377
 378   /* Return the language mask used for converting argv into a sequence
 379      of options.  */
 380   unsigned int (*option_lang_mask) (void);
 381
 382   /* Initialize variables in an options structure.  */
 383   void (*init_options_struct) (struct gcc_options *opts);
 384
 385   /* After the initialize_diagnostics hook is called, do any simple
 386      initialization needed before any calls to handle_option, other
 387      than that done by the init_options_struct hook.  */
 388   void (*init_options) (unsigned int decoded_options_count,
 389                         struct cl_decoded_option *decoded_options);
 390
 391   /* Callback used to perform language-specific initialization for the
 392      global diagnostic context structure.  */
 393   void (*initialize_diagnostics) (diagnostic_context *);
 394
 395   /* Beginning the main source file.  */
 396   void (*preprocess_main_file) (cpp_reader *, line_maps *,
 397                                 const line_map_ordinary *);
 398
 399   /* Adjust libcpp options and callbacks.  */
 400   void (*preprocess_options) (cpp_reader *);
 401
 402   /* Undefining a macro.  */
 403   void (*preprocess_undef) (cpp_reader *, location_t, cpp_hashnode *);
 404
 405   /* Observer for preprocessing stream.  */
 406   uintptr_t (*preprocess_token) (cpp_reader *, const cpp_token *, uintptr_t);
 407   /* Various flags it can return about the token.  */
 408   enum PT_flags
 409     {
 410      PT_begin_pragma = 1 << 0
 411     };
 412
 413   /* Register language-specific dumps.  */
 414   void (*register_dumps) (gcc::dump_manager *);
 415
 416   /* Return true if a warning should be given about option OPTION,
 417      which is for the wrong language, false if it should be quietly
 418      ignored.  */
 419   bool (*complain_wrong_lang_p) (const struct cl_option *option);
 420
 421   /* Handle the switch CODE, which has real type enum opt_code from
 422      options.h.  If the switch takes an argument, it is passed in ARG
 423      which points to permanent storage.  The handler is responsible for
 424      checking whether ARG is NULL, which indicates that no argument
 425      was in fact supplied.  For -f and -W switches, VALUE is 1 or 0
 426      for the positive and negative forms respectively.  HANDLERS should
 427      be passed to any recursive handle_option calls.  LOC is the
 428      location of the option.
 429
 430      Return true if the switch is valid, false if invalid.  */
 431   bool (*handle_option) (size_t code, const char *arg, HOST_WIDE_INT value,
 432                          int kind, location_t loc,
 433                          const struct cl_option_handlers *handlers);
 434
 435   /* Called when all command line options have been parsed to allow
 436      further processing and initialization
 437
 438      Should return true to indicate that a compiler back-end is
 439      not required, such as with the -E option.
 440
 441      If errorcount is nonzero after this call the compiler exits
 442      immediately and the finish hook is not called.  */
 443   bool (*post_options) (const char **);
 444
 445   /* Called after post_options to initialize the front end.  Return
 446      false to indicate that no further compilation be performed, in
 447      which case the finish hook is called immediately.  */
 448   bool (*init) (void);
 449
 450   /* Called at the end of compilation, as a finalizer.  */
 451   void (*finish) (void);
 452
 453   /* Parses the entire file.  */
 454   void (*parse_file) (void);
 455
 456   /* Determines if it's ok for a function to have no noreturn attribute.  */
 457   bool (*missing_noreturn_ok_p) (tree);
 458
 459   /* Called to obtain the alias set to be used for an expression or type.
 460      Returns -1 if the language does nothing special for it.  */
 461   alias_set_type (*get_alias_set) (tree);
 462
 463   /* Function to finish handling an incomplete decl at the end of
 464      compilation.  Default hook is does nothing.  */
 465   void (*finish_incomplete_decl) (tree);
 466
 467   /* Replace the DECL_LANG_SPECIFIC data, which may be NULL, of the
 468      DECL_NODE with a newly GC-allocated copy.  */
 469   void (*dup_lang_specific_decl) (tree);
 470
 471   /* Set the DECL_ASSEMBLER_NAME for a node.  If it is the sort of
 472      thing that the assembler should talk about, set
 473      DECL_ASSEMBLER_NAME to an appropriate IDENTIFIER_NODE.
 474      Otherwise, set it to the ERROR_MARK_NODE to ensure that the
 475      assembler does not talk about it.  */
 476   void (*set_decl_assembler_name) (tree);
 477
 478   /* Overwrite the DECL_ASSEMBLER_NAME for a node.  The name is being
 479      changed (including to or from NULL_TREE).  */
 480   void (*overwrite_decl_assembler_name) (tree, tree);
 481
 482   /* The front end can add its own statistics to -fmem-report with
 483      this hook.  It should output to stderr.  */
 484   void (*print_statistics) (void);
 485
 486   /* Called by print_tree when there is a tree of class tcc_exceptional
 487      or tcc_constant that it doesn't know how to display.  */
 488   lang_print_tree_hook print_xnode;
 489
 490   /* Called to print language-dependent parts of tcc_decl, tcc_type,
 491      and IDENTIFIER_NODE nodes.  */
 492   lang_print_tree_hook print_decl;
 493   lang_print_tree_hook print_type;
 494   lang_print_tree_hook print_identifier;
 495
 496   /* Computes the name to use to print a declaration.  DECL is the
 497      non-NULL declaration in question.  VERBOSITY determines what
 498      information will be printed: 0: DECL_NAME, demangled as
 499      necessary.  1: and scope information.  2: and any other
 500      information that might be interesting, such as function parameter
 501      types in C++.  The name is in the internal character set and
 502      needs to be converted to the locale character set of diagnostics,
 503      or to the execution character set for strings such as
 504      __PRETTY_FUNCTION__.  */
 505   const char *(*decl_printable_name) (tree decl, int verbosity);
 506
 507   /* Computes the dwarf-2/3 name for a tree.  VERBOSITY determines what
 508      information will be printed: 0: DECL_NAME, demangled as
 509      necessary.  1: and scope information.  */
 510   const char *(*dwarf_name) (tree, int verbosity);
 511
 512   /* This compares two types for equivalence ("compatible" in C-based languages).
 513      This routine should only return 1 if it is sure.  It should not be used
 514      in contexts where erroneously returning 0 causes problems.  */
 515   int (*types_compatible_p) (tree x, tree y);
 516
 517   /* Called by report_error_function to print out function name.  */
 518   void (*print_error_function) (diagnostic_context *, const char *,
 519                                 struct diagnostic_info *);
 520
 521   /* Convert a character from the host's to the target's character
 522      set.  The character should be in what C calls the "basic source
 523      character set" (roughly, the set of characters defined by plain
 524      old ASCII).  The default is to return the character unchanged,
 525      which is correct in most circumstances.  Note that both argument
 526      and result should be sign-extended under -fsigned-char,
 527      zero-extended under -fno-signed-char.  */
 528   HOST_WIDE_INT (*to_target_charset) (HOST_WIDE_INT);
 529
 530   /* Pointers to machine-independent attribute tables, for front ends
 531      using attribs.cc.  If one is NULL, it is ignored.  Respectively, a
 532      table of attributes specific to the language, a table of
 533      attributes common to two or more languages (to allow easy
 534      sharing), and a table of attributes for checking formats.  */
 535   const struct attribute_spec *attribute_table;
 536   const struct attribute_spec *common_attribute_table;
 537   const struct attribute_spec *format_attribute_table;
 538
 539   struct lang_hooks_for_tree_inlining tree_inlining;
 540
 541   struct lang_hooks_for_tree_dump tree_dump;
 542
 543   struct lang_hooks_for_decls decls;
 544
 545   struct lang_hooks_for_types types;
 546
 547   struct lang_hooks_for_lto lto;
 548
 549   /* Returns a TREE_VEC of the generic parameters of an instantiation of
 550      a generic type or decl, e.g. C++ template instantiation.  If
 551      TREE_CHAIN of the return value is set, it is an INTEGER_CST
 552      indicating how many of the elements are non-default.  */
 553   tree (*get_innermost_generic_parms) (const_tree);
 554
 555   /* Returns the TREE_VEC of arguments of an instantiation
 556      of a generic type of decl, e.g. C++ template instantiation.  */
 557   tree (*get_innermost_generic_args) (const_tree);
 558
 559   /* Determine if a tree is a function parameter pack.  */
 560   bool (*function_parameter_pack_p) (const_tree);
 561
 562   /* Perform language-specific gimplification on the argument.  Returns an
 563      enum gimplify_status, though we can't see that type here.  */
 564   int (*gimplify_expr) (tree *, gimple_seq *, gimple_seq *);
 565
 566   /* Do language specific processing in the builtin function DECL  */
 567   tree (*builtin_function) (tree decl);
 568
 569   /* Like builtin_function, but make sure the scope is the external scope.
 570      This is used to delay putting in back end builtin functions until the ISA
 571      that defines the builtin is declared via function specific target options,
 572      which can save memory for machines like the x86_64 that have multiple
 573      ISAs.  If this points to the same function as builtin_function, the
 574      backend must add all of the builtins at program initialization time.  */
 575   tree (*builtin_function_ext_scope) (tree decl);
 576
 577   /* Do language-specific processing for target-specific built-in
 578      function DECL, so that it is defined in the global scope (only)
 579      and is available without needing to be explicitly declared.
 580
 581      This is intended for targets that want to inject declarations of
 582      built-in functions into the source language (such as in response
 583      to a pragma) rather than providing them in the source language itself.  */
 584   tree (*simulate_builtin_function_decl) (tree decl);
 585
 586   /* Used to set up the tree_contains_structure array for a frontend. */
 587   void (*init_ts) (void);
 588
 589   /* Called by recompute_tree_invariant_for_addr_expr to go from EXPR
 590      to a contained expression or DECL, possibly updating *TC or *SE
 591      if in the process TREE_CONSTANT or TREE_SIDE_EFFECTS need updating.  */
 592   tree (*expr_to_decl) (tree expr, bool *tc, bool *se);
 593
 594   /* The EH personality function decl.  */
 595   tree (*eh_personality) (void);
 596
 597   /* Map a type to a runtime object to match type.  */
 598   tree (*eh_runtime_type) (tree);
 599
 600   /* If non-NULL, this is a function that returns a function decl to be
 601      executed if an unhandled exception is propagated out of a cleanup
 602      region.  For example, in C++, an exception thrown by a destructor
 603      during stack unwinding is required to result in a call to
 604      `std::terminate', so the C++ version of this function returns a
 605      FUNCTION_DECL for `std::terminate'.  */
 606   tree (*eh_protect_cleanup_actions) (void);
 607
 608   /* Return true if a stmt can fallthru.  Used by block_may_fallthru
 609      to possibly handle language trees.  */
 610   bool (*block_may_fallthru) (const_tree);
 611
 612   /* True if this language uses __cxa_end_cleanup when the ARM EABI
 613      is enabled.  */
 614   bool eh_use_cxa_end_cleanup;
 615
 616   /* True if this language requires deep unsharing of tree nodes prior to
 617      gimplification.  */
 618   bool deep_unsharing;
 619
 620   /* True if this language may use custom descriptors for nested functions
 621      instead of trampolines.  */
 622   bool custom_function_descriptors;
 623
 624   /* True if this language emits begin stmt notes.  */
 625   bool emits_begin_stmt;
 626
 627   /* Run all lang-specific selftests.  */
 628   void (*run_lang_selftests) (void);
 629
 630   /* Attempt to determine the source location of the substring.
 631      If successful, return NULL and write the source location to *OUT_LOC.
 632      Otherwise return an error message.  Error messages are intended
 633      for GCC developers (to help debugging) rather than for end-users.  */
 634   const char *(*get_substring_location) (const substring_loc &,
 635                                          location_t *out_loc);
 636
 637   /* Invoked before the early_finish debug hook is invoked.  */
 638   void (*finalize_early_debug) (void);
 639
 640   /* Get a value for the SARIF v2.1.0 "artifact.sourceLanguage" property
 641      for FILENAME, or return NULL.
 642      See SARIF v2.1.0 Appendix J for suggested values for common programming
 643      languages.  */
 644   const char *(*get_sarif_source_language) (const char *filename);
 645
 646   /* Whenever you add entries here, make sure you adjust langhooks-def.h
 647      and langhooks.cc accordingly.  */
 648 };
 649
 650 /* Each front end provides its own.  */
 651 extern struct lang_hooks lang_hooks;
 652
 653 extern tree add_builtin_function (const char *name, tree type,
 654                                   int function_code, enum built_in_class cl,
 655                                   const char *library_name,
 656                                   tree attrs);
 657
 658 extern tree add_builtin_function_ext_scope (const char *name, tree type,
 659                                             int function_code,
 660                                             enum built_in_class cl,
 661                                             const char *library_name,
 662                                             tree attrs);
 663 extern tree simulate_builtin_function_decl (location_t, const char *, tree,
 664                                             int, const char *, tree);
 665 extern tree add_builtin_type (const char *name, tree type);
 666
 667 /* Language helper functions.  */
 668
 669 extern bool lang_GNU_C (void);
 670 extern bool lang_GNU_CXX (void);
 671 extern bool lang_GNU_Fortran (void);
 672 extern bool lang_GNU_OBJC (void);
 673
 674 #endif /* GCC_LANG_HOOKS_H */