gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright (C) 2001-2016 Free Software Foundation, Inc.
   3    Contributed by Alexandre Oliva  <aoliva@redhat.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "target.h"
  25 #include "rtl.h"
  26 #include "tree.h"
  27 #include "timevar.h"
  28 #include "stringpool.h"
  29 #include "diagnostic.h"
  30 #include "intl.h"
  31 #include "toplev.h"
  32 #include "attribs.h"
  33 #include "gimplify.h"
  34 #include "langhooks.h"
  35 #include "tree-diagnostic.h"
  36 #include "output.h"
  37 #include "timevar.h"
  38
  39 /* Do nothing; in many cases the default hook.  */
  40
  41 void
  42 lhd_do_nothing (void)
  43 {
  44 }
  45
  46 /* Do nothing (tree).  */
  47
  48 void
  49 lhd_do_nothing_t (tree ARG_UNUSED (t))
  50 {
  51 }
  52
  53 /* Pass through (tree).  */
  54 tree
  55 lhd_pass_through_t (tree t)
  56 {
  57   return t;
  58 }
  59
  60 /* Do nothing (int, int, int).  Return NULL_TREE.  */
  61
  62 tree
  63 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  64                                      int ARG_UNUSED (j),
  65                                      int ARG_UNUSED (k))
  66 {
  67   return NULL_TREE;
  68 }
  69
  70 /* Do nothing (function).  */
  71
  72 void
  73 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  74 {
  75 }
  76
  77 /* Do nothing (return NULL_TREE).  */
  78
  79 tree
  80 lhd_return_null_tree_v (void)
  81 {
  82   return NULL_TREE;
  83 }
  84
  85 /* Do nothing (return NULL_TREE).  */
  86
  87 tree
  88 lhd_return_null_tree (tree ARG_UNUSED (t))
  89 {
  90   return NULL_TREE;
  91 }
  92
  93 /* Do nothing (return NULL_TREE).  */
  94
  95 tree
  96 lhd_return_null_const_tree (const_tree ARG_UNUSED (t))
  97 {
  98   return NULL_TREE;
  99 }
 100
 101 /* The default post options hook.  */
 102
 103 bool
 104 lhd_post_options (const char ** ARG_UNUSED (pfilename))
 105 {
 106   /* Excess precision other than "fast" requires front-end
 107      support.  */
 108   flag_excess_precision_cmdline = EXCESS_PRECISION_FAST;
 109   return false;
 110 }
 111
 112 /* Called from by print-tree.c.  */
 113
 114 void
 115 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 116                         tree ARG_UNUSED (node),
 117                         int ARG_UNUSED (indent))
 118 {
 119 }
 120
 121 /* Called from check_global_declaration.  */
 122
 123 bool
 124 lhd_warn_unused_global_decl (const_tree decl)
 125 {
 126   /* This is what used to exist in check_global_declaration.  Probably
 127      not many of these actually apply to non-C languages.  */
 128
 129   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 130     return false;
 131   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 132     return false;
 133   if (DECL_IN_SYSTEM_HEADER (decl))
 134     return false;
 135
 136   return true;
 137 }
 138
 139 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 140 void
 141 lhd_set_decl_assembler_name (tree decl)
 142 {
 143   tree id;
 144
 145   /* set_decl_assembler_name may be called on TYPE_DECL to record ODR
 146      name for C++ types.  By default types have no ODR names.  */
 147   if (TREE_CODE (decl) == TYPE_DECL)
 148     return;
 149
 150   /* The language-independent code should never use the
 151      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 152      VAR_DECLs for variables with static storage duration need a real
 153      DECL_ASSEMBLER_NAME.  */
 154   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 155               || (TREE_CODE (decl) == VAR_DECL
 156                   && (TREE_STATIC (decl)
 157                       || DECL_EXTERNAL (decl)
 158                       || TREE_PUBLIC (decl))));
 159
 160   /* By default, assume the name to use in assembly code is the same
 161      as that used in the source language.  (That's correct for C, and
 162      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 163      DECL_NAME in build_decl, so this choice provides backwards
 164      compatibility with existing front-ends.  This assumption is wrapped
 165      in a target hook, to allow for target-specific modification of the
 166      identifier.
 167
 168      Can't use just the variable's own name for a variable whose scope
 169      is less than the whole compilation.  Concatenate a distinguishing
 170      number - we use the DECL_UID.  */
 171
 172   if (TREE_PUBLIC (decl) || DECL_FILE_SCOPE_P (decl))
 173     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 174   else
 175     {
 176       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 177       char *label;
 178
 179       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 180       id = get_identifier (label);
 181     }
 182   SET_DECL_ASSEMBLER_NAME (decl, id);
 183
 184 }
 185
 186 /* Type promotion for variable arguments.  */
 187 tree
 188 lhd_type_promotes_to (tree ARG_UNUSED (type))
 189 {
 190   gcc_unreachable ();
 191 }
 192
 193 /* Registration of machine- or os-specific builtin types.  */
 194 void
 195 lhd_register_builtin_type (tree ARG_UNUSED (type),
 196                            const char * ARG_UNUSED (name))
 197 {
 198 }
 199
 200 /* Invalid use of an incomplete type.  */
 201 void
 202 lhd_incomplete_type_error (location_t ARG_UNUSED (loc),
 203                            const_tree ARG_UNUSED (value), const_tree type)
 204 {
 205   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 206   return;
 207 }
 208
 209 /* Provide a default routine for alias sets that always returns -1.  This
 210    is used by languages that don't need to do anything special.  */
 211
 212 alias_set_type
 213 lhd_get_alias_set (tree ARG_UNUSED (t))
 214 {
 215   return -1;
 216 }
 217
 218 /* This is the default decl_printable_name function.  */
 219
 220 const char *
 221 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 222 {
 223   gcc_assert (decl && DECL_NAME (decl));
 224   return IDENTIFIER_POINTER (DECL_NAME (decl));
 225 }
 226
 227 /* This is the default dwarf_name function.  */
 228
 229 const char *
 230 lhd_dwarf_name (tree t, int verbosity)
 231 {
 232   gcc_assert (DECL_P (t));
 233
 234   return lang_hooks.decl_printable_name (t, verbosity);
 235 }
 236
 237 /* This compares two types for equivalence ("compatible" in C-based languages).
 238    This routine should only return 1 if it is sure.  It should not be used
 239    in contexts where erroneously returning 0 causes problems.  */
 240
 241 int
 242 lhd_types_compatible_p (tree x, tree y)
 243 {
 244   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 245 }
 246
 247 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 248    nodes.  Returns nonzero if it does not want the usual dumping of the
 249    second argument.  */
 250
 251 bool
 252 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 253 {
 254   return false;
 255 }
 256
 257 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 258    language-specific way.  */
 259
 260 int
 261 lhd_tree_dump_type_quals (const_tree t)
 262 {
 263   return TYPE_QUALS (t);
 264 }
 265
 266 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 267
 268 int
 269 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED,
 270                    gimple_seq *pre_p ATTRIBUTE_UNUSED,
 271                    gimple_seq *post_p ATTRIBUTE_UNUSED)
 272 {
 273   return GS_UNHANDLED;
 274 }
 275
 276 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 277    which is a language-specific tree code in category tcc_constant or
 278    tcc_exceptional.  The default expects never to be called.  */
 279 size_t
 280 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 281 {
 282   gcc_unreachable ();
 283 }
 284
 285 /* Return true if decl, which is a function decl, may be called by a
 286    sibcall.  */
 287
 288 bool
 289 lhd_decl_ok_for_sibcall (const_tree decl ATTRIBUTE_UNUSED)
 290 {
 291   return true;
 292 }
 293
 294 /* Generic global declaration processing.  This is meant to be called
 295    by the front-ends at the end of parsing.  C/C++ do their own thing,
 296    but other front-ends may call this.  */
 297
 298 void
 299 global_decl_processing (void)
 300 {
 301   tree globals, decl, *vec;
 302   int len, i;
 303
 304   timevar_stop (TV_PHASE_PARSING);
 305   timevar_start (TV_PHASE_DEFERRED);
 306   /* Really define vars that have had only a tentative definition.
 307      Really output inline functions that must actually be callable
 308      and have not been output so far.  */
 309
 310   globals = lang_hooks.decls.getdecls ();
 311   len = list_length (globals);
 312   vec = XNEWVEC (tree, len);
 313
 314   /* Process the decls in reverse order--earliest first.
 315      Put them into VEC from back to front, then take out from front.  */
 316
 317   for (i = 0, decl = globals; i < len; i++, decl = DECL_CHAIN (decl))
 318     vec[len - i - 1] = decl;
 319
 320   wrapup_global_declarations (vec, len);
 321   timevar_stop (TV_PHASE_DEFERRED);
 322
 323   timevar_start (TV_PHASE_PARSING);
 324   free (vec);
 325 }
 326
 327 /* Called to perform language-specific initialization of CTX.  */
 328 void
 329 lhd_initialize_diagnostics (diagnostic_context *ctx ATTRIBUTE_UNUSED)
 330 {
 331 }
 332
 333 /* Called to perform language-specific options initialization.  */
 334 void
 335 lhd_init_options (unsigned int decoded_options_count ATTRIBUTE_UNUSED,
 336                   struct cl_decoded_option *decoded_options ATTRIBUTE_UNUSED)
 337 {
 338 }
 339
 340 /* By default, always complain about options for the wrong language.  */
 341 bool
 342 lhd_complain_wrong_lang_p (const struct cl_option *option ATTRIBUTE_UNUSED)
 343 {
 344   return true;
 345 }
 346
 347 /* By default, no language-specific options are valid.  */
 348 bool
 349 lhd_handle_option (size_t code ATTRIBUTE_UNUSED,
 350                    const char *arg ATTRIBUTE_UNUSED,
 351                    int value ATTRIBUTE_UNUSED, int kind ATTRIBUTE_UNUSED,
 352                    location_t loc ATTRIBUTE_UNUSED,
 353                    const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 354 {
 355   return false;
 356 }
 357
 358 /* The default function to print out name of current function that caused
 359    an error.  */
 360 void
 361 lhd_print_error_function (diagnostic_context *context, const char *file,
 362                           diagnostic_info *diagnostic)
 363 {
 364   if (diagnostic_last_function_changed (context, diagnostic))
 365     {
 366       const char *old_prefix = context->printer->prefix;
 367       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 368       char *new_prefix = (file && abstract_origin == NULL)
 369                          ? file_name_as_prefix (context, file) : NULL;
 370
 371       pp_set_prefix (context->printer, new_prefix);
 372
 373       if (current_function_decl == NULL)
 374         pp_printf (context->printer, _("At top level:"));
 375       else
 376         {
 377           tree fndecl, ao;
 378
 379           if (abstract_origin)
 380             {
 381               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 382               while (TREE_CODE (ao) == BLOCK
 383                      && BLOCK_ABSTRACT_ORIGIN (ao)
 384                      && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 385                 ao = BLOCK_ABSTRACT_ORIGIN (ao);
 386               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 387               fndecl = ao;
 388             }
 389           else
 390             fndecl = current_function_decl;
 391
 392           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 393             pp_printf
 394               (context->printer, _("In member function %qs"),
 395                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 396           else
 397             pp_printf
 398               (context->printer, _("In function %qs"),
 399                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 400
 401           while (abstract_origin)
 402             {
 403               location_t *locus;
 404               tree block = abstract_origin;
 405
 406               locus = &BLOCK_SOURCE_LOCATION (block);
 407               fndecl = NULL;
 408               block = BLOCK_SUPERCONTEXT (block);
 409               while (block && TREE_CODE (block) == BLOCK
 410                      && BLOCK_ABSTRACT_ORIGIN (block))
 411                 {
 412                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 413
 414                   while (TREE_CODE (ao) == BLOCK
 415                          && BLOCK_ABSTRACT_ORIGIN (ao)
 416                          && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 417                     ao = BLOCK_ABSTRACT_ORIGIN (ao);
 418
 419                   if (TREE_CODE (ao) == FUNCTION_DECL)
 420                     {
 421                       fndecl = ao;
 422                       break;
 423                     }
 424                   else if (TREE_CODE (ao) != BLOCK)
 425                     break;
 426
 427                   block = BLOCK_SUPERCONTEXT (block);
 428                 }
 429               if (fndecl)
 430                 abstract_origin = block;
 431               else
 432                 {
 433                   while (block && TREE_CODE (block) == BLOCK)
 434                     block = BLOCK_SUPERCONTEXT (block);
 435
 436                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 437                     fndecl = block;
 438                   abstract_origin = NULL;
 439                 }
 440               if (fndecl)
 441                 {
 442                   expanded_location s = expand_location (*locus);
 443                   pp_comma (context->printer);
 444                   pp_newline (context->printer);
 445                   if (s.file != NULL)
 446                     {
 447                       if (context->show_column)
 448                         pp_printf (context->printer,
 449                                    _("    inlined from %qs at %r%s:%d:%d%R"),
 450                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 451                                    "locus", s.file, s.line, s.column);
 452                       else
 453                         pp_printf (context->printer,
 454                                    _("    inlined from %qs at %r%s:%d%R"),
 455                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 456                                    "locus", s.file, s.line);
 457
 458                     }
 459                   else
 460                     pp_printf (context->printer, _("    inlined from %qs"),
 461                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 462                 }
 463             }
 464           pp_colon (context->printer);
 465         }
 466
 467       diagnostic_set_last_function (context, diagnostic);
 468       pp_newline_and_flush (context->printer);
 469       context->printer->prefix = old_prefix;
 470       free ((char*) new_prefix);
 471     }
 472 }
 473
 474 tree
 475 lhd_make_node (enum tree_code code)
 476 {
 477   return make_node (code);
 478 }
 479
 480 HOST_WIDE_INT
 481 lhd_to_target_charset (HOST_WIDE_INT c)
 482 {
 483   return c;
 484 }
 485
 486 tree
 487 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 488 {
 489   return expr;
 490 }
 491
 492 /* Return sharing kind if OpenMP sharing attribute of DECL is
 493    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 494
 495 enum omp_clause_default_kind
 496 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 497 {
 498   if (DECL_ARTIFICIAL (decl))
 499     return OMP_CLAUSE_DEFAULT_SHARED;
 500   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 501 }
 502
 503 /* Generate code to copy SRC to DST.  */
 504
 505 tree
 506 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 507 {
 508   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 509 }
 510
 511 /* Finalize clause C.  */
 512
 513 void
 514 lhd_omp_finish_clause (tree, gimple_seq *)
 515 {
 516 }
 517
 518 /* Register language specific type size variables as potentially OpenMP
 519    firstprivate variables.  */
 520
 521 void
 522 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 523                                    tree t ATTRIBUTE_UNUSED)
 524 {
 525 }
 526
 527 /* Return true if TYPE is an OpenMP mappable type.  */
 528
 529 bool
 530 lhd_omp_mappable_type (tree type)
 531 {
 532   /* Mappable type has to be complete.  */
 533   if (type == error_mark_node || !COMPLETE_TYPE_P (type))
 534     return false;
 535   return true;
 536 }
 537
 538 /* Common function for add_builtin_function and
 539    add_builtin_function_ext_scope.  */
 540 static tree
 541 add_builtin_function_common (const char *name,
 542                              tree type,
 543                              int function_code,
 544                              enum built_in_class cl,
 545                              const char *library_name,
 546                              tree attrs,
 547                              tree (*hook) (tree))
 548 {
 549   tree   id = get_identifier (name);
 550   tree decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, id, type);
 551
 552   TREE_PUBLIC (decl)         = 1;
 553   DECL_EXTERNAL (decl)       = 1;
 554   DECL_BUILT_IN_CLASS (decl) = cl;
 555
 556   DECL_FUNCTION_CODE (decl)  = (enum built_in_function) function_code;
 557
 558   /* DECL_FUNCTION_CODE is a bitfield; verify that the value fits.  */
 559   gcc_assert (DECL_FUNCTION_CODE (decl) == function_code);
 560
 561   if (library_name)
 562     {
 563       tree libname = get_identifier (library_name);
 564
 565       libname = targetm.mangle_decl_assembler_name (decl, libname);
 566       SET_DECL_ASSEMBLER_NAME (decl, libname);
 567     }
 568
 569   /* Possibly apply some default attributes to this built-in function.  */
 570   if (attrs)
 571     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 572   else
 573     decl_attributes (&decl, NULL_TREE, 0);
 574
 575   return hook (decl);
 576
 577 }
 578
 579 /* Create a builtin function.  */
 580
 581 tree
 582 add_builtin_function (const char *name,
 583                       tree type,
 584                       int function_code,
 585                       enum built_in_class cl,
 586                       const char *library_name,
 587                       tree attrs)
 588 {
 589   return add_builtin_function_common (name, type, function_code, cl,
 590                                       library_name, attrs,
 591                                       lang_hooks.builtin_function);
 592 }
 593
 594 /* Like add_builtin_function, but make sure the scope is the external scope.
 595    This is used to delay putting in back end builtin functions until the ISA
 596    that defines the builtin is declared via function specific target options,
 597    which can save memory for machines like the x86_64 that have multiple ISAs.
 598    If this points to the same function as builtin_function, the backend must
 599    add all of the builtins at program initialization time.  */
 600
 601 tree
 602 add_builtin_function_ext_scope (const char *name,
 603                                 tree type,
 604                                 int function_code,
 605                                 enum built_in_class cl,
 606                                 const char *library_name,
 607                                 tree attrs)
 608 {
 609   return add_builtin_function_common (name, type, function_code, cl,
 610                                       library_name, attrs,
 611                                       lang_hooks.builtin_function_ext_scope);
 612 }
 613
 614 tree
 615 lhd_builtin_function (tree decl)
 616 {
 617   lang_hooks.decls.pushdecl (decl);
 618   return decl;
 619 }
 620
 621 /* Create a builtin type.  */
 622
 623 tree
 624 add_builtin_type (const char *name, tree type)
 625 {
 626   tree   id = get_identifier (name);
 627   tree decl = build_decl (BUILTINS_LOCATION, TYPE_DECL, id, type);
 628   return lang_hooks.decls.pushdecl (decl);
 629 }
 630
 631 /* LTO hooks.  */
 632
 633 /* Used to save and restore any previously active section.  */
 634 static section *saved_section;
 635
 636
 637 /* Begin a new LTO output section named NAME.  This default implementation
 638    saves the old section and emits assembly code to switch to the new
 639    section.  */
 640
 641 void
 642 lhd_begin_section (const char *name)
 643 {
 644   section *section;
 645
 646   /* Save the old section so we can restore it in lto_end_asm_section.  */
 647   gcc_assert (!saved_section);
 648   saved_section = in_section;
 649   if (!saved_section)
 650     saved_section = text_section;
 651
 652   /* Create a new section and switch to it.  */
 653   section = get_section (name, SECTION_DEBUG | SECTION_EXCLUDE, NULL);
 654   switch_to_section (section);
 655 }
 656
 657
 658 /* Write DATA of length LEN to the current LTO output section.  This default
 659    implementation just calls assemble_string.  */
 660
 661 void
 662 lhd_append_data (const void *data, size_t len, void *)
 663 {
 664   if (data)
 665     {
 666       timevar_push (TV_IPA_LTO_OUTPUT);
 667       assemble_string ((const char *)data, len);
 668       timevar_pop (TV_IPA_LTO_OUTPUT);
 669     }
 670 }
 671
 672
 673 /* Finish the current LTO output section.  This default implementation emits
 674    assembly code to switch to any section previously saved by
 675    lhd_begin_section.  */
 676
 677 void
 678 lhd_end_section (void)
 679 {
 680   if (saved_section)
 681     {
 682       switch_to_section (saved_section);
 683       saved_section = NULL;
 684     }
 685 }
 686
 687 /* Default implementation of enum_underlying_base_type using type_for_size.  */
 688
 689 tree
 690 lhd_enum_underlying_base_type (const_tree enum_type)
 691 {
 692   return lang_hooks.types.type_for_size (TYPE_PRECISION (enum_type),
 693                                          TYPE_UNSIGNED (enum_type));
 694 }
 695
 696 /* Default implementation of LANG_HOOKS_GET_SUBSTRING_LOCATION.  */
 697
 698 const char *
 699 lhd_get_substring_location (const substring_loc &, location_t *)
 700 {
 701   return "unimplemented";
 702 }
 703
 704 /* Returns true if the current lang_hooks represents the GNU C frontend.  */
 705
 706 bool
 707 lang_GNU_C (void)
 708 {
 709   return (strncmp (lang_hooks.name, "GNU C", 5) == 0
 710           && (lang_hooks.name[5] == '\0' || ISDIGIT (lang_hooks.name[5])));
 711 }
 712
 713 /* Returns true if the current lang_hooks represents the GNU C++ frontend.  */
 714
 715 bool
 716 lang_GNU_CXX (void)
 717 {
 718   return strncmp (lang_hooks.name, "GNU C++", 7) == 0;
 719 }
 720
 721 /* Returns true if the current lang_hooks represents the GNU Fortran frontend.  */
 722
 723 bool
 724 lang_GNU_Fortran (void)
 725 {
 726   return strncmp (lang_hooks.name, "GNU Fortran", 11) == 0;
 727 }
 728
 729 /* Returns true if the current lang_hooks represents the GNU Objective-C
 730    frontend.  */
 731
 732 bool
 733 lang_GNU_OBJC (void)
 734 {
 735   return strncmp (lang_hooks.name, "GNU Objective-C", 15) == 0;
 736 }