gcc/langhooks.h

   1 /* The lang_hooks data structure.
   2    Copyright (C) 2001-2018 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.c.  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.c.  */
  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   /* Return what kind of RECORD_TYPE this is, mainly for purposes of
  68      debug information.  If not defined, record types are assumed to
  69      be structures.  */
  70   enum classify_record (*classify_record) (tree);
  71
  72   /* Given MODE and UNSIGNEDP, return a suitable type-tree with that
  73      mode.  */
  74   tree (*type_for_mode) (machine_mode, int);
  75
  76   /* Given PRECISION and UNSIGNEDP, return a suitable type-tree for an
  77      integer type with at least that precision.  */
  78   tree (*type_for_size) (unsigned, int);
  79
  80   /* True if the type is an instantiation of a generic type,
  81      e.g. C++ template implicit specializations.  */
  82   bool (*generic_p) (const_tree);
  83
  84   /* Returns the TREE_VEC of elements of a given generic argument pack.  */
  85   tree (*get_argument_pack_elems) (const_tree);
  86
  87   /* Given a type, apply default promotions to unnamed function
  88      arguments and return the new type.  Return the same type if no
  89      change.  Required by any language that supports variadic
  90      arguments.  The default hook dies.  */
  91   tree (*type_promotes_to) (tree);
  92
  93   /* Register TYPE as a builtin type with the indicated NAME.  The
  94      TYPE is placed in the outermost lexical scope.  The semantics
  95      should be analogous to:
  96
  97        typedef TYPE NAME;
  98
  99      in C.  The default hook ignores the declaration.  */
 100   void (*register_builtin_type) (tree, const char *);
 101
 102   /* This routine is called in tree.c to print an error message for
 103      invalid use of an incomplete type.  VALUE is the expression that
 104      was used (or 0 if that isn't known) and TYPE is the type that was
 105      invalid.  LOC is the location of the use.  */
 106   void (*incomplete_type_error) (location_t loc, const_tree value,
 107                                  const_tree type);
 108
 109   /* Called from assign_temp to return the maximum size, if there is one,
 110      for a type.  */
 111   tree (*max_size) (const_tree);
 112
 113   /* Register language specific type size variables as potentially OpenMP
 114      firstprivate variables.  */
 115   void (*omp_firstprivatize_type_sizes) (struct gimplify_omp_ctx *, tree);
 116
 117   /* Return true if TYPE is a mappable type.  */
 118   bool (*omp_mappable_type) (tree type);
 119
 120   /* Return TRUE if TYPE1 and TYPE2 are identical for type hashing purposes.
 121      Called only after doing all language independent checks.
 122      At present, this function is only called when both TYPE1 and TYPE2 are
 123      FUNCTION_TYPE or METHOD_TYPE.  */
 124   bool (*type_hash_eq) (const_tree, const_tree);
 125
 126   /* If non-NULL, return TYPE1 with any language-specific modifiers copied from
 127      TYPE2.  */
 128   tree (*copy_lang_qualifiers) (const_tree, const_tree);
 129
 130   /* Return TRUE if TYPE uses a hidden descriptor and fills in information
 131      for the debugger about the array bounds, strides, etc.  */
 132   bool (*get_array_descr_info) (const_tree, struct array_descr_info *);
 133
 134   /* Fill in information for the debugger about the bounds of TYPE.  */
 135   void (*get_subrange_bounds) (const_tree, tree *, tree *);
 136
 137   /* Called on INTEGER_TYPEs.  Return NULL_TREE for non-biased types.  For
 138      biased types, return as an INTEGER_CST node the value that is represented
 139      by a physical zero.  */
 140   tree (*get_type_bias) (const_tree);
 141
 142   /* A type descriptive of TYPE's complex layout generated to help the
 143      debugger to decode variable-length or self-referential constructs.
 144      This is only used for the AT_GNAT_descriptive_type DWARF attribute.  */
 145   tree (*descriptive_type) (const_tree);
 146
 147   /* If we requested a pointer to a vector, build up the pointers that
 148      we stripped off while looking for the inner type.  Similarly for
 149      return values from functions.  The argument TYPE is the top of the
 150      chain, and BOTTOM is the new type which we will point to.  */
 151   tree (*reconstruct_complex_type) (tree, tree);
 152
 153   /* Returns the tree that represents the underlying data type used to
 154      implement the enumeration.  The default implementation will just use
 155      type_for_size.  Used in dwarf2out.c to add a DW_AT_type base type
 156      reference to a DW_TAG_enumeration.  */
 157   tree (*enum_underlying_base_type) (const_tree);
 158
 159   /* Return a type to use in the debug info instead of TYPE, or NULL_TREE to
 160      keep TYPE.  This is useful to keep a single "source type" when the
 161      middle-end uses specialized types, for instance constrained discriminated
 162      types in Ada.  */
 163   tree (*get_debug_type) (const_tree);
 164
 165   /* Return TRUE if TYPE implements a fixed point type and fills in information
 166      for the debugger about scale factor, etc.  */
 167   bool (*get_fixed_point_type_info) (const_tree,
 168                                      struct fixed_point_type_info *);
 169
 170   /* Returns -1 if dwarf ATTR shouldn't be added for TYPE, or the attribute
 171      value otherwise.  */
 172   int (*type_dwarf_attribute) (const_tree, int);
 173
 174   /* Returns a tree for the unit size of T excluding tail padding that
 175      might be used by objects inheriting from T.  */
 176   tree (*unit_size_without_reusable_padding) (tree);
 177 };
 178
 179 /* Language hooks related to decls and the symbol table.  */
 180
 181 struct lang_hooks_for_decls
 182 {
 183   /* Return true if we are in the global binding level.  This hook is really
 184      needed only if the language supports variable-sized types at the global
 185      level, i.e. declared outside subprograms.  */
 186   bool (*global_bindings_p) (void);
 187
 188   /* Function to add a decl to the current scope level.  Takes one
 189      argument, a decl to add.  Returns that decl, or, if the same
 190      symbol is already declared, may return a different decl for that
 191      name.  */
 192   tree (*pushdecl) (tree);
 193
 194   /* Returns the chain of decls so far in the current scope level.  */
 195   tree (*getdecls) (void);
 196
 197   /* Returns -1 if dwarf ATTR shouldn't be added for DECL, or the attribute
 198      value otherwise.  */
 199   int (*decl_dwarf_attribute) (const_tree, int);
 200
 201   /* Returns True if the parameter is a generic parameter decl
 202      of a generic type, e.g a template template parameter for the C++ FE.  */
 203   bool (*generic_generic_parameter_decl_p) (const_tree);
 204
 205   /* Determine if a function parameter got expanded from a
 206      function parameter pack.  */
 207   bool (*function_parm_expanded_from_pack_p) (tree, tree);
 208
 209   /* Returns the generic declaration of a generic function instantiations.  */
 210   tree (*get_generic_function_decl) (const_tree);
 211
 212   /* Returns true when we should warn for an unused global DECL.
 213      We will already have checked that it has static binding.  */
 214   bool (*warn_unused_global) (const_tree);
 215
 216   /* Perform any post compilation-proper parser cleanups and
 217      processing.  This is currently only needed for the C++ parser,
 218      which hopefully can be cleaned up so this hook is no longer
 219      necessary.  */
 220   void (*post_compilation_parsing_cleanups) (void);
 221
 222   /* True if this decl may be called via a sibcall.  */
 223   bool (*ok_for_sibcall) (const_tree);
 224
 225   /* True if OpenMP should privatize what this DECL points to rather
 226      than the DECL itself.  */
 227   bool (*omp_privatize_by_reference) (const_tree);
 228
 229   /* Return sharing kind if OpenMP sharing attribute of DECL is
 230      predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 231   enum omp_clause_default_kind (*omp_predetermined_sharing) (tree);
 232
 233   /* Return decl that should be reported for DEFAULT(NONE) failure
 234      diagnostics.  Usually the DECL passed in.  */
 235   tree (*omp_report_decl) (tree);
 236
 237   /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
 238      disregarded in OpenMP construct, because it is going to be
 239      remapped during OpenMP lowering.  SHARED is true if DECL
 240      is going to be shared, false if it is going to be privatized.  */
 241   bool (*omp_disregard_value_expr) (tree, bool);
 242
 243   /* Return true if DECL that is shared iff SHARED is true should
 244      be put into OMP_CLAUSE_PRIVATE_DEBUG.  */
 245   bool (*omp_private_debug_clause) (tree, bool);
 246
 247   /* Return true if DECL in private clause needs
 248      OMP_CLAUSE_PRIVATE_OUTER_REF on the private clause.  */
 249   bool (*omp_private_outer_ref) (tree);
 250
 251   /* Build and return code for a default constructor for DECL in
 252      response to CLAUSE.  OUTER is corresponding outer region's
 253      variable if needed.  Return NULL if nothing to be done.  */
 254   tree (*omp_clause_default_ctor) (tree clause, tree decl, tree outer);
 255
 256   /* Build and return code for a copy constructor from SRC to DST.  */
 257   tree (*omp_clause_copy_ctor) (tree clause, tree dst, tree src);
 258
 259   /* Similarly, except use an assignment operator instead.  */
 260   tree (*omp_clause_assign_op) (tree clause, tree dst, tree src);
 261
 262   /* Build and return code for a constructor of DST that sets it to
 263      SRC + ADD.  */
 264   tree (*omp_clause_linear_ctor) (tree clause, tree dst, tree src, tree add);
 265
 266   /* Build and return code destructing DECL.  Return NULL if nothing
 267      to be done.  */
 268   tree (*omp_clause_dtor) (tree clause, tree decl);
 269
 270   /* Do language specific checking on an implicitly determined clause.  */
 271   void (*omp_finish_clause) (tree clause, gimple_seq *pre_p);
 272
 273   /* Return true if DECL is a scalar variable (for the purpose of
 274      implicit firstprivatization).  */
 275   bool (*omp_scalar_p) (tree decl);
 276 };
 277
 278 /* Language hooks related to LTO serialization.  */
 279
 280 struct lang_hooks_for_lto
 281 {
 282   /* Begin a new LTO section named NAME.  */
 283   void (*begin_section) (const char *name);
 284
 285   /* Write DATA of length LEN to the currently open LTO section.  BLOCK is a
 286      pointer to the dynamically allocated memory containing DATA.  The
 287      append_data function is responsible for freeing it when it is no longer
 288      needed.  */
 289   void (*append_data) (const void *data, size_t len, void *block);
 290
 291   /* End the previously begun LTO section.  */
 292   void (*end_section) (void);
 293 };
 294
 295 /* Language-specific hooks.  See langhooks-def.h for defaults.  */
 296
 297 struct lang_hooks
 298 {
 299   /* String identifying the front end and optionally language standard
 300      version, e.g. "GNU C++98".  */
 301   const char *name;
 302
 303   /* sizeof (struct lang_identifier), so make_node () creates
 304      identifier nodes long enough for the language-specific slots.  */
 305   size_t identifier_size;
 306
 307   /* Remove any parts of the tree that are used only by the FE. */
 308   void (*free_lang_data) (tree);
 309
 310   /* Determines the size of any language-specific tcc_constant,
 311      tcc_exceptional or tcc_type nodes.  Since it is called from
 312      make_node, the only information available is the tree code.
 313      Expected to die on unrecognized codes.  */
 314   size_t (*tree_size) (enum tree_code);
 315
 316   /* Return the language mask used for converting argv into a sequence
 317      of options.  */
 318   unsigned int (*option_lang_mask) (void);
 319
 320   /* Initialize variables in an options structure.  */
 321   void (*init_options_struct) (struct gcc_options *opts);
 322
 323   /* After the initialize_diagnostics hook is called, do any simple
 324      initialization needed before any calls to handle_option, other
 325      than that done by the init_options_struct hook.  */
 326   void (*init_options) (unsigned int decoded_options_count,
 327                         struct cl_decoded_option *decoded_options);
 328
 329   /* Callback used to perform language-specific initialization for the
 330      global diagnostic context structure.  */
 331   void (*initialize_diagnostics) (diagnostic_context *);
 332
 333   /* Register language-specific dumps.  */
 334   void (*register_dumps) (gcc::dump_manager *);
 335
 336   /* Return true if a warning should be given about option OPTION,
 337      which is for the wrong language, false if it should be quietly
 338      ignored.  */
 339   bool (*complain_wrong_lang_p) (const struct cl_option *option);
 340
 341   /* Handle the switch CODE, which has real type enum opt_code from
 342      options.h.  If the switch takes an argument, it is passed in ARG
 343      which points to permanent storage.  The handler is responsible for
 344      checking whether ARG is NULL, which indicates that no argument
 345      was in fact supplied.  For -f and -W switches, VALUE is 1 or 0
 346      for the positive and negative forms respectively.  HANDLERS should
 347      be passed to any recursive handle_option calls.  LOC is the
 348      location of the option.
 349
 350      Return true if the switch is valid, false if invalid.  */
 351   bool (*handle_option) (size_t code, const char *arg, HOST_WIDE_INT value,
 352                          int kind, location_t loc,
 353                          const struct cl_option_handlers *handlers);
 354
 355   /* Called when all command line options have been parsed to allow
 356      further processing and initialization
 357
 358      Should return true to indicate that a compiler back-end is
 359      not required, such as with the -E option.
 360
 361      If errorcount is nonzero after this call the compiler exits
 362      immediately and the finish hook is not called.  */
 363   bool (*post_options) (const char **);
 364
 365   /* Called after post_options to initialize the front end.  Return
 366      false to indicate that no further compilation be performed, in
 367      which case the finish hook is called immediately.  */
 368   bool (*init) (void);
 369
 370   /* Called at the end of compilation, as a finalizer.  */
 371   void (*finish) (void);
 372
 373   /* Parses the entire file.  */
 374   void (*parse_file) (void);
 375
 376   /* Determines if it's ok for a function to have no noreturn attribute.  */
 377   bool (*missing_noreturn_ok_p) (tree);
 378
 379   /* Called to obtain the alias set to be used for an expression or type.
 380      Returns -1 if the language does nothing special for it.  */
 381   alias_set_type (*get_alias_set) (tree);
 382
 383   /* Function to finish handling an incomplete decl at the end of
 384      compilation.  Default hook is does nothing.  */
 385   void (*finish_incomplete_decl) (tree);
 386
 387   /* Replace the DECL_LANG_SPECIFIC data, which may be NULL, of the
 388      DECL_NODE with a newly GC-allocated copy.  */
 389   void (*dup_lang_specific_decl) (tree);
 390
 391   /* Set the DECL_ASSEMBLER_NAME for a node.  If it is the sort of
 392      thing that the assembler should talk about, set
 393      DECL_ASSEMBLER_NAME to an appropriate IDENTIFIER_NODE.
 394      Otherwise, set it to the ERROR_MARK_NODE to ensure that the
 395      assembler does not talk about it.  */
 396   void (*set_decl_assembler_name) (tree);
 397
 398   /* Overwrite the DECL_ASSEMBLER_NAME for a node.  The name is being
 399      changed (including to or from NULL_TREE).  */
 400   void (*overwrite_decl_assembler_name) (tree, tree);
 401
 402   /* The front end can add its own statistics to -fmem-report with
 403      this hook.  It should output to stderr.  */
 404   void (*print_statistics) (void);
 405
 406   /* Called by print_tree when there is a tree of class tcc_exceptional
 407      that it doesn't know how to display.  */
 408   lang_print_tree_hook print_xnode;
 409
 410   /* Called to print language-dependent parts of tcc_decl, tcc_type,
 411      and IDENTIFIER_NODE nodes.  */
 412   lang_print_tree_hook print_decl;
 413   lang_print_tree_hook print_type;
 414   lang_print_tree_hook print_identifier;
 415
 416   /* Computes the name to use to print a declaration.  DECL is the
 417      non-NULL declaration in question.  VERBOSITY determines what
 418      information will be printed: 0: DECL_NAME, demangled as
 419      necessary.  1: and scope information.  2: and any other
 420      information that might be interesting, such as function parameter
 421      types in C++.  The name is in the internal character set and
 422      needs to be converted to the locale character set of diagnostics,
 423      or to the execution character set for strings such as
 424      __PRETTY_FUNCTION__.  */
 425   const char *(*decl_printable_name) (tree decl, int verbosity);
 426
 427   /* Computes the dwarf-2/3 name for a tree.  VERBOSITY determines what
 428      information will be printed: 0: DECL_NAME, demangled as
 429      necessary.  1: and scope information.  */
 430   const char *(*dwarf_name) (tree, int verbosity);
 431
 432   /* This compares two types for equivalence ("compatible" in C-based languages).
 433      This routine should only return 1 if it is sure.  It should not be used
 434      in contexts where erroneously returning 0 causes problems.  */
 435   int (*types_compatible_p) (tree x, tree y);
 436
 437   /* Called by report_error_function to print out function name.  */
 438   void (*print_error_function) (diagnostic_context *, const char *,
 439                                 struct diagnostic_info *);
 440
 441   /* Convert a character from the host's to the target's character
 442      set.  The character should be in what C calls the "basic source
 443      character set" (roughly, the set of characters defined by plain
 444      old ASCII).  The default is to return the character unchanged,
 445      which is correct in most circumstances.  Note that both argument
 446      and result should be sign-extended under -fsigned-char,
 447      zero-extended under -fno-signed-char.  */
 448   HOST_WIDE_INT (*to_target_charset) (HOST_WIDE_INT);
 449
 450   /* Pointers to machine-independent attribute tables, for front ends
 451      using attribs.c.  If one is NULL, it is ignored.  Respectively, a
 452      table of attributes specific to the language, a table of
 453      attributes common to two or more languages (to allow easy
 454      sharing), and a table of attributes for checking formats.  */
 455   const struct attribute_spec *attribute_table;
 456   const struct attribute_spec *common_attribute_table;
 457   const struct attribute_spec *format_attribute_table;
 458
 459   struct lang_hooks_for_tree_inlining tree_inlining;
 460
 461   struct lang_hooks_for_tree_dump tree_dump;
 462
 463   struct lang_hooks_for_decls decls;
 464
 465   struct lang_hooks_for_types types;
 466
 467   struct lang_hooks_for_lto lto;
 468
 469   /* Returns a TREE_VEC of the generic parameters of an instantiation of
 470      a generic type or decl, e.g. C++ template instantiation.  If
 471      TREE_CHAIN of the return value is set, it is an INTEGER_CST
 472      indicating how many of the elements are non-default.  */
 473   tree (*get_innermost_generic_parms) (const_tree);
 474
 475   /* Returns the TREE_VEC of arguments of an instantiation
 476      of a generic type of decl, e.g. C++ template instantiation.  */
 477   tree (*get_innermost_generic_args) (const_tree);
 478
 479   /* Determine if a tree is a function parameter pack.  */
 480   bool (*function_parameter_pack_p) (const_tree);
 481
 482   /* Perform language-specific gimplification on the argument.  Returns an
 483      enum gimplify_status, though we can't see that type here.  */
 484   int (*gimplify_expr) (tree *, gimple_seq *, gimple_seq *);
 485
 486   /* Do language specific processing in the builtin function DECL  */
 487   tree (*builtin_function) (tree decl);
 488
 489   /* Like builtin_function, but make sure the scope is the external scope.
 490      This is used to delay putting in back end builtin functions until the ISA
 491      that defines the builtin is declared via function specific target options,
 492      which can save memory for machines like the x86_64 that have multiple
 493      ISAs.  If this points to the same function as builtin_function, the
 494      backend must add all of the builtins at program initialization time.  */
 495   tree (*builtin_function_ext_scope) (tree decl);
 496
 497   /* Used to set up the tree_contains_structure array for a frontend. */
 498   void (*init_ts) (void);
 499
 500   /* Called by recompute_tree_invariant_for_addr_expr to go from EXPR
 501      to a contained expression or DECL, possibly updating *TC or *SE
 502      if in the process TREE_CONSTANT or TREE_SIDE_EFFECTS need updating.  */
 503   tree (*expr_to_decl) (tree expr, bool *tc, bool *se);
 504
 505   /* The EH personality function decl.  */
 506   tree (*eh_personality) (void);
 507
 508   /* Map a type to a runtime object to match type.  */
 509   tree (*eh_runtime_type) (tree);
 510
 511   /* If non-NULL, this is a function that returns a function decl to be
 512      executed if an unhandled exception is propagated out of a cleanup
 513      region.  For example, in C++, an exception thrown by a destructor
 514      during stack unwinding is required to result in a call to
 515      `std::terminate', so the C++ version of this function returns a
 516      FUNCTION_DECL for `std::terminate'.  */
 517   tree (*eh_protect_cleanup_actions) (void);
 518
 519   /* Return true if a stmt can fallthru.  Used by block_may_fallthru
 520      to possibly handle language trees.  */
 521   bool (*block_may_fallthru) (const_tree);
 522
 523   /* True if this language uses __cxa_end_cleanup when the ARM EABI
 524      is enabled.  */
 525   bool eh_use_cxa_end_cleanup;
 526
 527   /* True if this language requires deep unsharing of tree nodes prior to
 528      gimplification.  */
 529   bool deep_unsharing;
 530
 531   /* True if this language may use custom descriptors for nested functions
 532      instead of trampolines.  */
 533   bool custom_function_descriptors;
 534
 535   /* True if this language emits begin stmt notes.  */
 536   bool emits_begin_stmt;
 537
 538   /* Run all lang-specific selftests.  */
 539   void (*run_lang_selftests) (void);
 540
 541   /* Attempt to determine the source location of the substring.
 542      If successful, return NULL and write the source location to *OUT_LOC.
 543      Otherwise return an error message.  Error messages are intended
 544      for GCC developers (to help debugging) rather than for end-users.  */
 545   const char *(*get_substring_location) (const substring_loc &,
 546                                          location_t *out_loc);
 547
 548   /* Whenever you add entries here, make sure you adjust langhooks-def.h
 549      and langhooks.c accordingly.  */
 550 };
 551
 552 /* Each front end provides its own.  */
 553 extern struct lang_hooks lang_hooks;
 554
 555 extern tree add_builtin_function (const char *name, tree type,
 556                                   int function_code, enum built_in_class cl,
 557                                   const char *library_name,
 558                                   tree attrs);
 559
 560 extern tree add_builtin_function_ext_scope (const char *name, tree type,
 561                                             int function_code,
 562                                             enum built_in_class cl,
 563                                             const char *library_name,
 564                                             tree attrs);
 565 extern tree add_builtin_type (const char *name, tree type);
 566
 567 /* Language helper functions.  */
 568
 569 extern bool lang_GNU_C (void);
 570 extern bool lang_GNU_CXX (void);
 571 extern bool lang_GNU_Fortran (void);
 572 extern bool lang_GNU_OBJC (void);
 573
 574 #endif /* GCC_LANG_HOOKS_H */