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 (tree ARG_UNUSED (t))
  81 {
  82   return NULL_TREE;
  83 }
  84
  85 /* Do nothing (return NULL_TREE).  */
  86
  87 tree
  88 lhd_return_null_const_tree (const_tree ARG_UNUSED (t))
  89 {
  90   return NULL_TREE;
  91 }
  92
  93 /* The default post options hook.  */
  94
  95 bool
  96 lhd_post_options (const char ** ARG_UNUSED (pfilename))
  97 {
  98   /* Excess precision other than "fast" requires front-end
  99      support.  */
 100   flag_excess_precision_cmdline = EXCESS_PRECISION_FAST;
 101   return false;
 102 }
 103
 104 /* Called from by print-tree.c.  */
 105
 106 void
 107 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 108                         tree ARG_UNUSED (node),
 109                         int ARG_UNUSED (indent))
 110 {
 111 }
 112
 113 /* Called from check_global_declaration.  */
 114
 115 bool
 116 lhd_warn_unused_global_decl (const_tree decl)
 117 {
 118   /* This is what used to exist in check_global_declaration.  Probably
 119      not many of these actually apply to non-C languages.  */
 120
 121   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 122     return false;
 123   if (VAR_P (decl) && TREE_READONLY (decl))
 124     return false;
 125   if (DECL_IN_SYSTEM_HEADER (decl))
 126     return false;
 127
 128   return true;
 129 }
 130
 131 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 132 void
 133 lhd_set_decl_assembler_name (tree decl)
 134 {
 135   tree id;
 136
 137   /* set_decl_assembler_name may be called on TYPE_DECL to record ODR
 138      name for C++ types.  By default types have no ODR names.  */
 139   if (TREE_CODE (decl) == TYPE_DECL)
 140     return;
 141
 142   /* The language-independent code should never use the
 143      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 144      VAR_DECLs for variables with static storage duration need a real
 145      DECL_ASSEMBLER_NAME.  */
 146   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 147               || (VAR_P (decl)
 148                   && (TREE_STATIC (decl)
 149                       || DECL_EXTERNAL (decl)
 150                       || TREE_PUBLIC (decl))));
 151
 152   /* By default, assume the name to use in assembly code is the same
 153      as that used in the source language.  (That's correct for C, and
 154      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 155      DECL_NAME in build_decl, so this choice provides backwards
 156      compatibility with existing front-ends.  This assumption is wrapped
 157      in a target hook, to allow for target-specific modification of the
 158      identifier.
 159
 160      Can't use just the variable's own name for a variable whose scope
 161      is less than the whole compilation.  Concatenate a distinguishing
 162      number - we use the DECL_UID.  */
 163
 164   if (TREE_PUBLIC (decl) || DECL_FILE_SCOPE_P (decl))
 165     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 166   else
 167     {
 168       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 169       char *label;
 170
 171       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 172       id = get_identifier (label);
 173     }
 174   SET_DECL_ASSEMBLER_NAME (decl, id);
 175
 176 }
 177
 178 /* Type promotion for variable arguments.  */
 179 tree
 180 lhd_type_promotes_to (tree ARG_UNUSED (type))
 181 {
 182   gcc_unreachable ();
 183 }
 184
 185 /* Registration of machine- or os-specific builtin types.  */
 186 void
 187 lhd_register_builtin_type (tree ARG_UNUSED (type),
 188                            const char * ARG_UNUSED (name))
 189 {
 190 }
 191
 192 /* Invalid use of an incomplete type.  */
 193 void
 194 lhd_incomplete_type_error (location_t ARG_UNUSED (loc),
 195                            const_tree ARG_UNUSED (value), const_tree type)
 196 {
 197   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 198   return;
 199 }
 200
 201 /* Provide a default routine for alias sets that always returns -1.  This
 202    is used by languages that don't need to do anything special.  */
 203
 204 alias_set_type
 205 lhd_get_alias_set (tree ARG_UNUSED (t))
 206 {
 207   return -1;
 208 }
 209
 210 /* This is the default decl_printable_name function.  */
 211
 212 const char *
 213 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 214 {
 215   gcc_assert (decl && DECL_NAME (decl));
 216   return IDENTIFIER_POINTER (DECL_NAME (decl));
 217 }
 218
 219 /* This is the default dwarf_name function.  */
 220
 221 const char *
 222 lhd_dwarf_name (tree t, int verbosity)
 223 {
 224   gcc_assert (DECL_P (t));
 225
 226   return lang_hooks.decl_printable_name (t, verbosity);
 227 }
 228
 229 /* This compares two types for equivalence ("compatible" in C-based languages).
 230    This routine should only return 1 if it is sure.  It should not be used
 231    in contexts where erroneously returning 0 causes problems.  */
 232
 233 int
 234 lhd_types_compatible_p (tree x, tree y)
 235 {
 236   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 237 }
 238
 239 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 240    nodes.  Returns nonzero if it does not want the usual dumping of the
 241    second argument.  */
 242
 243 bool
 244 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 245 {
 246   return false;
 247 }
 248
 249 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 250    language-specific way.  */
 251
 252 int
 253 lhd_tree_dump_type_quals (const_tree t)
 254 {
 255   return TYPE_QUALS (t);
 256 }
 257
 258 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 259
 260 int
 261 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED,
 262                    gimple_seq *pre_p ATTRIBUTE_UNUSED,
 263                    gimple_seq *post_p ATTRIBUTE_UNUSED)
 264 {
 265   return GS_UNHANDLED;
 266 }
 267
 268 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 269    which is a language-specific tree code in category tcc_constant or
 270    tcc_exceptional.  The default expects never to be called.  */
 271 size_t
 272 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 273 {
 274   gcc_unreachable ();
 275 }
 276
 277 /* Return true if decl, which is a function decl, may be called by a
 278    sibcall.  */
 279
 280 bool
 281 lhd_decl_ok_for_sibcall (const_tree decl ATTRIBUTE_UNUSED)
 282 {
 283   return true;
 284 }
 285
 286 /* Generic global declaration processing.  This is meant to be called
 287    by the front-ends at the end of parsing.  C/C++ do their own thing,
 288    but other front-ends may call this.  */
 289
 290 void
 291 global_decl_processing (void)
 292 {
 293   tree globals, decl, *vec;
 294   int len, i;
 295
 296   timevar_stop (TV_PHASE_PARSING);
 297   timevar_start (TV_PHASE_DEFERRED);
 298   /* Really define vars that have had only a tentative definition.
 299      Really output inline functions that must actually be callable
 300      and have not been output so far.  */
 301
 302   globals = lang_hooks.decls.getdecls ();
 303   len = list_length (globals);
 304   vec = XNEWVEC (tree, len);
 305
 306   /* Process the decls in reverse order--earliest first.
 307      Put them into VEC from back to front, then take out from front.  */
 308
 309   for (i = 0, decl = globals; i < len; i++, decl = DECL_CHAIN (decl))
 310     vec[len - i - 1] = decl;
 311
 312   wrapup_global_declarations (vec, len);
 313   timevar_stop (TV_PHASE_DEFERRED);
 314
 315   timevar_start (TV_PHASE_PARSING);
 316   free (vec);
 317 }
 318
 319 /* Called to perform language-specific initialization of CTX.  */
 320 void
 321 lhd_initialize_diagnostics (diagnostic_context *ctx ATTRIBUTE_UNUSED)
 322 {
 323 }
 324
 325 /* Called to perform language-specific options initialization.  */
 326 void
 327 lhd_init_options (unsigned int decoded_options_count ATTRIBUTE_UNUSED,
 328                   struct cl_decoded_option *decoded_options ATTRIBUTE_UNUSED)
 329 {
 330 }
 331
 332 /* By default, always complain about options for the wrong language.  */
 333 bool
 334 lhd_complain_wrong_lang_p (const struct cl_option *option ATTRIBUTE_UNUSED)
 335 {
 336   return true;
 337 }
 338
 339 /* By default, no language-specific options are valid.  */
 340 bool
 341 lhd_handle_option (size_t code ATTRIBUTE_UNUSED,
 342                    const char *arg ATTRIBUTE_UNUSED,
 343                    int value ATTRIBUTE_UNUSED, int kind ATTRIBUTE_UNUSED,
 344                    location_t loc ATTRIBUTE_UNUSED,
 345                    const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 346 {
 347   return false;
 348 }
 349
 350 /* The default function to print out name of current function that caused
 351    an error.  */
 352 void
 353 lhd_print_error_function (diagnostic_context *context, const char *file,
 354                           diagnostic_info *diagnostic)
 355 {
 356   if (diagnostic_last_function_changed (context, diagnostic))
 357     {
 358       const char *old_prefix = context->printer->prefix;
 359       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 360       char *new_prefix = (file && abstract_origin == NULL)
 361                          ? file_name_as_prefix (context, file) : NULL;
 362
 363       pp_set_prefix (context->printer, new_prefix);
 364
 365       if (current_function_decl == NULL)
 366         pp_printf (context->printer, _("At top level:"));
 367       else
 368         {
 369           tree fndecl, ao;
 370
 371           if (abstract_origin)
 372             {
 373               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 374               while (TREE_CODE (ao) == BLOCK
 375                      && BLOCK_ABSTRACT_ORIGIN (ao)
 376                      && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 377                 ao = BLOCK_ABSTRACT_ORIGIN (ao);
 378               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 379               fndecl = ao;
 380             }
 381           else
 382             fndecl = current_function_decl;
 383
 384           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 385             pp_printf
 386               (context->printer, _("In member function %qs"),
 387                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 388           else
 389             pp_printf
 390               (context->printer, _("In function %qs"),
 391                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 392
 393           while (abstract_origin)
 394             {
 395               location_t *locus;
 396               tree block = abstract_origin;
 397
 398               locus = &BLOCK_SOURCE_LOCATION (block);
 399               fndecl = NULL;
 400               block = BLOCK_SUPERCONTEXT (block);
 401               while (block && TREE_CODE (block) == BLOCK
 402                      && BLOCK_ABSTRACT_ORIGIN (block))
 403                 {
 404                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 405
 406                   while (TREE_CODE (ao) == BLOCK
 407                          && BLOCK_ABSTRACT_ORIGIN (ao)
 408                          && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 409                     ao = BLOCK_ABSTRACT_ORIGIN (ao);
 410
 411                   if (TREE_CODE (ao) == FUNCTION_DECL)
 412                     {
 413                       fndecl = ao;
 414                       break;
 415                     }
 416                   else if (TREE_CODE (ao) != BLOCK)
 417                     break;
 418
 419                   block = BLOCK_SUPERCONTEXT (block);
 420                 }
 421               if (fndecl)
 422                 abstract_origin = block;
 423               else
 424                 {
 425                   while (block && TREE_CODE (block) == BLOCK)
 426                     block = BLOCK_SUPERCONTEXT (block);
 427
 428                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 429                     fndecl = block;
 430                   abstract_origin = NULL;
 431                 }
 432               if (fndecl)
 433                 {
 434                   expanded_location s = expand_location (*locus);
 435                   pp_comma (context->printer);
 436                   pp_newline (context->printer);
 437                   if (s.file != NULL)
 438                     {
 439                       if (context->show_column)
 440                         pp_printf (context->printer,
 441                                    _("    inlined from %qs at %r%s:%d:%d%R"),
 442                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 443                                    "locus", s.file, s.line, s.column);
 444                       else
 445                         pp_printf (context->printer,
 446                                    _("    inlined from %qs at %r%s:%d%R"),
 447                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 448                                    "locus", s.file, s.line);
 449
 450                     }
 451                   else
 452                     pp_printf (context->printer, _("    inlined from %qs"),
 453                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 454                 }
 455             }
 456           pp_colon (context->printer);
 457         }
 458
 459       diagnostic_set_last_function (context, diagnostic);
 460       pp_newline_and_flush (context->printer);
 461       context->printer->prefix = old_prefix;
 462       free ((char*) new_prefix);
 463     }
 464 }
 465
 466 tree
 467 lhd_make_node (enum tree_code code)
 468 {
 469   return make_node (code);
 470 }
 471
 472 HOST_WIDE_INT
 473 lhd_to_target_charset (HOST_WIDE_INT c)
 474 {
 475   return c;
 476 }
 477
 478 tree
 479 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 480 {
 481   return expr;
 482 }
 483
 484 /* Return sharing kind if OpenMP sharing attribute of DECL is
 485    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 486
 487 enum omp_clause_default_kind
 488 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 489 {
 490   if (DECL_ARTIFICIAL (decl))
 491     return OMP_CLAUSE_DEFAULT_SHARED;
 492   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 493 }
 494
 495 /* Generate code to copy SRC to DST.  */
 496
 497 tree
 498 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 499 {
 500   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 501 }
 502
 503 /* Finalize clause C.  */
 504
 505 void
 506 lhd_omp_finish_clause (tree, gimple_seq *)
 507 {
 508 }
 509
 510 /* Return true if DECL is a scalar variable (for the purpose of
 511    implicit firstprivatization).  */
 512
 513 bool
 514 lhd_omp_scalar_p (tree decl)
 515 {
 516   tree type = TREE_TYPE (decl);
 517   if (TREE_CODE (type) == REFERENCE_TYPE)
 518     type = TREE_TYPE (type);
 519   if (TREE_CODE (type) == COMPLEX_TYPE)
 520     type = TREE_TYPE (type);
 521   if (INTEGRAL_TYPE_P (type)
 522       || SCALAR_FLOAT_TYPE_P (type)
 523       || TREE_CODE (type) == POINTER_TYPE)
 524     return true;
 525   return false;
 526 }
 527
 528 /* Register language specific type size variables as potentially OpenMP
 529    firstprivate variables.  */
 530
 531 void
 532 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 533                                    tree t ATTRIBUTE_UNUSED)
 534 {
 535 }
 536
 537 /* Return true if TYPE is an OpenMP mappable type.  */
 538
 539 bool
 540 lhd_omp_mappable_type (tree type)
 541 {
 542   /* Mappable type has to be complete.  */
 543   if (type == error_mark_node || !COMPLETE_TYPE_P (type))
 544     return false;
 545   return true;
 546 }
 547
 548 /* Common function for add_builtin_function and
 549    add_builtin_function_ext_scope.  */
 550 static tree
 551 add_builtin_function_common (const char *name,
 552                              tree type,
 553                              int function_code,
 554                              enum built_in_class cl,
 555                              const char *library_name,
 556                              tree attrs,
 557                              tree (*hook) (tree))
 558 {
 559   tree   id = get_identifier (name);
 560   tree decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, id, type);
 561
 562   TREE_PUBLIC (decl)         = 1;
 563   DECL_EXTERNAL (decl)       = 1;
 564   DECL_BUILT_IN_CLASS (decl) = cl;
 565
 566   DECL_FUNCTION_CODE (decl)  = (enum built_in_function) function_code;
 567
 568   /* DECL_FUNCTION_CODE is a bitfield; verify that the value fits.  */
 569   gcc_assert (DECL_FUNCTION_CODE (decl) == function_code);
 570
 571   if (library_name)
 572     {
 573       tree libname = get_identifier (library_name);
 574
 575       libname = targetm.mangle_decl_assembler_name (decl, libname);
 576       SET_DECL_ASSEMBLER_NAME (decl, libname);
 577     }
 578
 579   /* Possibly apply some default attributes to this built-in function.  */
 580   if (attrs)
 581     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 582   else
 583     decl_attributes (&decl, NULL_TREE, 0);
 584
 585   return hook (decl);
 586
 587 }
 588
 589 /* Create a builtin function.  */
 590
 591 tree
 592 add_builtin_function (const char *name,
 593                       tree type,
 594                       int function_code,
 595                       enum built_in_class cl,
 596                       const char *library_name,
 597                       tree attrs)
 598 {
 599   return add_builtin_function_common (name, type, function_code, cl,
 600                                       library_name, attrs,
 601                                       lang_hooks.builtin_function);
 602 }
 603
 604 /* Like add_builtin_function, but make sure the scope is the external scope.
 605    This is used to delay putting in back end builtin functions until the ISA
 606    that defines the builtin is declared via function specific target options,
 607    which can save memory for machines like the x86_64 that have multiple ISAs.
 608    If this points to the same function as builtin_function, the backend must
 609    add all of the builtins at program initialization time.  */
 610
 611 tree
 612 add_builtin_function_ext_scope (const char *name,
 613                                 tree type,
 614                                 int function_code,
 615                                 enum built_in_class cl,
 616                                 const char *library_name,
 617                                 tree attrs)
 618 {
 619   return add_builtin_function_common (name, type, function_code, cl,
 620                                       library_name, attrs,
 621                                       lang_hooks.builtin_function_ext_scope);
 622 }
 623
 624 tree
 625 lhd_builtin_function (tree decl)
 626 {
 627   lang_hooks.decls.pushdecl (decl);
 628   return decl;
 629 }
 630
 631 /* Create a builtin type.  */
 632
 633 tree
 634 add_builtin_type (const char *name, tree type)
 635 {
 636   tree   id = get_identifier (name);
 637   tree decl = build_decl (BUILTINS_LOCATION, TYPE_DECL, id, type);
 638   return lang_hooks.decls.pushdecl (decl);
 639 }
 640
 641 /* LTO hooks.  */
 642
 643 /* Used to save and restore any previously active section.  */
 644 static section *saved_section;
 645
 646
 647 /* Begin a new LTO output section named NAME.  This default implementation
 648    saves the old section and emits assembly code to switch to the new
 649    section.  */
 650
 651 void
 652 lhd_begin_section (const char *name)
 653 {
 654   section *section;
 655
 656   /* Save the old section so we can restore it in lto_end_asm_section.  */
 657   gcc_assert (!saved_section);
 658   saved_section = in_section;
 659   if (!saved_section)
 660     saved_section = text_section;
 661
 662   /* Create a new section and switch to it.  */
 663   section = get_section (name, SECTION_DEBUG | SECTION_EXCLUDE, NULL);
 664   switch_to_section (section);
 665 }
 666
 667
 668 /* Write DATA of length LEN to the current LTO output section.  This default
 669    implementation just calls assemble_string.  */
 670
 671 void
 672 lhd_append_data (const void *data, size_t len, void *)
 673 {
 674   if (data)
 675     {
 676       timevar_push (TV_IPA_LTO_OUTPUT);
 677       assemble_string ((const char *)data, len);
 678       timevar_pop (TV_IPA_LTO_OUTPUT);
 679     }
 680 }
 681
 682
 683 /* Finish the current LTO output section.  This default implementation emits
 684    assembly code to switch to any section previously saved by
 685    lhd_begin_section.  */
 686
 687 void
 688 lhd_end_section (void)
 689 {
 690   if (saved_section)
 691     {
 692       switch_to_section (saved_section);
 693       saved_section = NULL;
 694     }
 695 }
 696
 697 /* Default implementation of enum_underlying_base_type using type_for_size.  */
 698
 699 tree
 700 lhd_enum_underlying_base_type (const_tree enum_type)
 701 {
 702   return lang_hooks.types.type_for_size (TYPE_PRECISION (enum_type),
 703                                          TYPE_UNSIGNED (enum_type));
 704 }
 705
 706 /* Default implementation of LANG_HOOKS_GET_SUBSTRING_LOCATION.  */
 707
 708 const char *
 709 lhd_get_substring_location (const substring_loc &, location_t *)
 710 {
 711   return "unimplemented";
 712 }
 713
 714 /* Default implementation of LANG_HOOKS_DECL_DWARF_ATTRIBUTE.  Don't add
 715    any attributes.  */
 716
 717 int
 718 lhd_decl_dwarf_attribute (const_tree, int)
 719 {
 720   return -1;
 721 }
 722
 723 /* Default implementation of LANG_HOOKS_TYPE_DWARF_ATTRIBUTE.  Don't add
 724    any attributes.  */
 725
 726 int
 727 lhd_type_dwarf_attribute (const_tree, int)
 728 {
 729   return -1;
 730 }
 731
 732 /* Returns true if the current lang_hooks represents the GNU C frontend.  */
 733
 734 bool
 735 lang_GNU_C (void)
 736 {
 737   return (strncmp (lang_hooks.name, "GNU C", 5) == 0
 738           && (lang_hooks.name[5] == '\0' || ISDIGIT (lang_hooks.name[5])));
 739 }
 740
 741 /* Returns true if the current lang_hooks represents the GNU C++ frontend.  */
 742
 743 bool
 744 lang_GNU_CXX (void)
 745 {
 746   return strncmp (lang_hooks.name, "GNU C++", 7) == 0;
 747 }
 748
 749 /* Returns true if the current lang_hooks represents the GNU Fortran frontend.  */
 750
 751 bool
 752 lang_GNU_Fortran (void)
 753 {
 754   return strncmp (lang_hooks.name, "GNU Fortran", 11) == 0;
 755 }
 756
 757 /* Returns true if the current lang_hooks represents the GNU Objective-C
 758    frontend.  */
 759
 760 bool
 761 lang_GNU_OBJC (void)
 762 {
 763   return strncmp (lang_hooks.name, "GNU Objective-C", 15) == 0;
 764 }