gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright (C) 2001-2020 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 #include "stor-layout.h"
  39 #include "cgraph.h"
  40 #include "debug.h"
  41
  42 /* Do nothing; in many cases the default hook.  */
  43
  44 void
  45 lhd_do_nothing (void)
  46 {
  47 }
  48
  49 /* Do nothing (tree).  */
  50
  51 void
  52 lhd_do_nothing_t (tree ARG_UNUSED (t))
  53 {
  54 }
  55
  56 /* Pass through (tree).  */
  57 tree
  58 lhd_pass_through_t (tree t)
  59 {
  60   return t;
  61 }
  62
  63 /* Do nothing (int, int, int).  Return NULL_TREE.  */
  64
  65 tree
  66 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  67                                      int ARG_UNUSED (j),
  68                                      int ARG_UNUSED (k))
  69 {
  70   return NULL_TREE;
  71 }
  72
  73 /* Do nothing (function).  */
  74
  75 void
  76 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  77 {
  78 }
  79
  80 /* Do nothing (return NULL_TREE).  */
  81
  82 tree
  83 lhd_return_null_tree (tree ARG_UNUSED (t))
  84 {
  85   return NULL_TREE;
  86 }
  87
  88 /* Do nothing (return NULL_TREE).  */
  89
  90 tree
  91 lhd_return_null_const_tree (const_tree ARG_UNUSED (t))
  92 {
  93   return NULL_TREE;
  94 }
  95
  96 /* The default post options hook.  */
  97
  98 bool
  99 lhd_post_options (const char ** ARG_UNUSED (pfilename))
 100 {
 101   /* Excess precision other than "fast" requires front-end
 102      support.  */
 103   flag_excess_precision = EXCESS_PRECISION_FAST;
 104   return false;
 105 }
 106
 107 /* Called from by print-tree.c.  */
 108
 109 void
 110 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 111                         tree ARG_UNUSED (node),
 112                         int ARG_UNUSED (indent))
 113 {
 114 }
 115
 116 /* Called from check_global_declaration.  */
 117
 118 bool
 119 lhd_warn_unused_global_decl (const_tree decl)
 120 {
 121   /* This is what used to exist in check_global_declaration.  Probably
 122      not many of these actually apply to non-C languages.  */
 123
 124   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 125     return false;
 126   if (VAR_P (decl) && TREE_READONLY (decl))
 127     return false;
 128   if (DECL_IN_SYSTEM_HEADER (decl))
 129     return false;
 130
 131   return true;
 132 }
 133
 134 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 135 void
 136 lhd_set_decl_assembler_name (tree decl)
 137 {
 138   tree id;
 139
 140   /* set_decl_assembler_name may be called on TYPE_DECL to record ODR
 141      name for C++ types.  By default types have no ODR names.  */
 142   if (TREE_CODE (decl) == TYPE_DECL)
 143     return;
 144
 145   /* The language-independent code should never use the
 146      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 147      VAR_DECLs for variables with static storage duration need a real
 148      DECL_ASSEMBLER_NAME.  */
 149   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 150               || (VAR_P (decl)
 151                   && (TREE_STATIC (decl)
 152                       || DECL_EXTERNAL (decl)
 153                       || TREE_PUBLIC (decl))));
 154
 155   /* By default, assume the name to use in assembly code is the same
 156      as that used in the source language.  (That's correct for C, and
 157      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 158      DECL_NAME in build_decl, so this choice provides backwards
 159      compatibility with existing front-ends.  This assumption is wrapped
 160      in a target hook, to allow for target-specific modification of the
 161      identifier.
 162
 163      Can't use just the variable's own name for a variable whose scope
 164      is less than the whole compilation.  Concatenate a distinguishing
 165      number.  */
 166
 167   if (TREE_PUBLIC (decl) || DECL_FILE_SCOPE_P (decl))
 168     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 169   else
 170     {
 171       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 172       static unsigned long num;
 173       char *label;
 174
 175       ASM_FORMAT_PRIVATE_NAME (label, name, num++);
 176       id = get_identifier (label);
 177     }
 178
 179   SET_DECL_ASSEMBLER_NAME (decl, id);
 180 }
 181
 182 /* Forcibly overwrite the DECL_ASSEMBLER_NAME for DECL to NAME.  */
 183 void
 184 lhd_overwrite_decl_assembler_name (tree decl, tree name)
 185 {
 186   DECL_ASSEMBLER_NAME_RAW (decl) = name;
 187 }
 188
 189 /* Type promotion for variable arguments.  */
 190 tree
 191 lhd_type_promotes_to (tree ARG_UNUSED (type))
 192 {
 193   gcc_unreachable ();
 194 }
 195
 196 /* Registration of machine- or os-specific builtin types.  */
 197 void
 198 lhd_register_builtin_type (tree ARG_UNUSED (type),
 199                            const char * ARG_UNUSED (name))
 200 {
 201 }
 202
 203 /* Invalid use of an incomplete type.  */
 204 void
 205 lhd_incomplete_type_error (location_t ARG_UNUSED (loc),
 206                            const_tree ARG_UNUSED (value), const_tree type)
 207 {
 208   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 209   return;
 210 }
 211
 212 /* Provide a default routine for alias sets that always returns -1.  This
 213    is used by languages that don't need to do anything special.  */
 214
 215 alias_set_type
 216 lhd_get_alias_set (tree ARG_UNUSED (t))
 217 {
 218   return -1;
 219 }
 220
 221 /* This is the default decl_printable_name function.  */
 222
 223 const char *
 224 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 225 {
 226   gcc_assert (decl && DECL_NAME (decl));
 227   return IDENTIFIER_POINTER (DECL_NAME (decl));
 228 }
 229
 230 /* This is the default dwarf_name function.  */
 231
 232 const char *
 233 lhd_dwarf_name (tree t, int verbosity)
 234 {
 235   gcc_assert (DECL_P (t));
 236
 237   return lang_hooks.decl_printable_name (t, verbosity);
 238 }
 239
 240 /* This compares two types for equivalence ("compatible" in C-based languages).
 241    This routine should only return 1 if it is sure.  It should not be used
 242    in contexts where erroneously returning 0 causes problems.  */
 243
 244 int
 245 lhd_types_compatible_p (tree x, tree y)
 246 {
 247   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 248 }
 249
 250 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 251    nodes.  Returns nonzero if it does not want the usual dumping of the
 252    second argument.  */
 253
 254 bool
 255 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 256 {
 257   return false;
 258 }
 259
 260 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 261    language-specific way.  */
 262
 263 int
 264 lhd_tree_dump_type_quals (const_tree t)
 265 {
 266   return TYPE_QUALS (t);
 267 }
 268
 269 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 270
 271 int
 272 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED,
 273                    gimple_seq *pre_p ATTRIBUTE_UNUSED,
 274                    gimple_seq *post_p ATTRIBUTE_UNUSED)
 275 {
 276   return GS_UNHANDLED;
 277 }
 278
 279 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 280    which is a language-specific tree code in category tcc_constant,
 281    tcc_exceptional or tcc_type.  The default expects never to be called.  */
 282 size_t
 283 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 284 {
 285   gcc_unreachable ();
 286 }
 287
 288 /* Return true if decl, which is a function decl, may be called by a
 289    sibcall.  */
 290
 291 bool
 292 lhd_decl_ok_for_sibcall (const_tree decl ATTRIBUTE_UNUSED)
 293 {
 294   return true;
 295 }
 296
 297 /* Generic global declaration processing.  This is meant to be called
 298    by the front-ends at the end of parsing.  C/C++ do their own thing,
 299    but other front-ends may call this.  */
 300
 301 void
 302 global_decl_processing (void)
 303 {
 304   tree globals, decl, *vec;
 305   int len, i;
 306
 307   timevar_stop (TV_PHASE_PARSING);
 308   timevar_start (TV_PHASE_DEFERRED);
 309   /* Really define vars that have had only a tentative definition.
 310      Really output inline functions that must actually be callable
 311      and have not been output so far.  */
 312
 313   globals = lang_hooks.decls.getdecls ();
 314   len = list_length (globals);
 315   vec = XNEWVEC (tree, len);
 316
 317   /* Process the decls in reverse order--earliest first.
 318      Put them into VEC from back to front, then take out from front.  */
 319
 320   for (i = 0, decl = globals; i < len; i++, decl = DECL_CHAIN (decl))
 321     vec[len - i - 1] = decl;
 322
 323   wrapup_global_declarations (vec, len);
 324   timevar_stop (TV_PHASE_DEFERRED);
 325
 326   timevar_start (TV_PHASE_PARSING);
 327   free (vec);
 328 }
 329
 330 /* Called to perform language-specific initialization of CTX.  */
 331 void
 332 lhd_initialize_diagnostics (diagnostic_context *ctx ATTRIBUTE_UNUSED)
 333 {
 334 }
 335
 336 /* Called to register dumps.  */
 337 void
 338 lhd_register_dumps (gcc::dump_manager *)
 339 {
 340 }
 341
 342 /* Called to perform language-specific options initialization.  */
 343 void
 344 lhd_init_options (unsigned int decoded_options_count ATTRIBUTE_UNUSED,
 345                   struct cl_decoded_option *decoded_options ATTRIBUTE_UNUSED)
 346 {
 347 }
 348
 349 /* By default, always complain about options for the wrong language.  */
 350 bool
 351 lhd_complain_wrong_lang_p (const struct cl_option *option ATTRIBUTE_UNUSED)
 352 {
 353   return true;
 354 }
 355
 356 /* By default, no language-specific options are valid.  */
 357 bool
 358 lhd_handle_option (size_t code ATTRIBUTE_UNUSED,
 359                    const char *arg ATTRIBUTE_UNUSED,
 360                    HOST_WIDE_INT value ATTRIBUTE_UNUSED,
 361                    int kind ATTRIBUTE_UNUSED,
 362                    location_t loc ATTRIBUTE_UNUSED,
 363                    const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 364 {
 365   return false;
 366 }
 367
 368 /* The default function to print out name of current function that caused
 369    an error.  */
 370 void
 371 lhd_print_error_function (diagnostic_context *context, const char *file,
 372                           diagnostic_info *diagnostic)
 373 {
 374   if (diagnostic_last_function_changed (context, diagnostic))
 375     {
 376       char *old_prefix = pp_take_prefix (context->printer);
 377       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 378       char *new_prefix = (file && abstract_origin == NULL)
 379                          ? file_name_as_prefix (context, file) : NULL;
 380
 381       pp_set_prefix (context->printer, new_prefix);
 382
 383       if (current_function_decl == NULL)
 384         pp_printf (context->printer, _("At top level:"));
 385       else
 386         {
 387           tree fndecl, ao;
 388
 389           if (abstract_origin)
 390             {
 391               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 392               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 393               fndecl = ao;
 394             }
 395           else
 396             fndecl = current_function_decl;
 397
 398           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 399             pp_printf
 400               (context->printer, _("In member function %qs"),
 401                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 402           else
 403             pp_printf
 404               (context->printer, _("In function %qs"),
 405                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 406
 407           while (abstract_origin)
 408             {
 409               location_t *locus;
 410               tree block = abstract_origin;
 411
 412               locus = &BLOCK_SOURCE_LOCATION (block);
 413               fndecl = NULL;
 414               block = BLOCK_SUPERCONTEXT (block);
 415               while (block && TREE_CODE (block) == BLOCK
 416                      && BLOCK_ABSTRACT_ORIGIN (block))
 417                 {
 418                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 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 /* Default implementation of LANG_HOOKS_SIMULATE_ENUM_DECL.  Assume a
 481    simple int-based enumerator (which is all the hook can be used for
 482    at present) and push each decl individually without any decoration.
 483
 484    This definition is suitable for LTO and is generic enough that it
 485    might be reusable elsewhere.  */
 486 tree
 487 lhd_simulate_enum_decl (location_t loc, const char *name,
 488                         vec<string_int_pair> values)
 489 {
 490   tree enumtype = lang_hooks.types.make_type (ENUMERAL_TYPE);
 491   tree enumdecl = build_decl (loc, TYPE_DECL, get_identifier (name), enumtype);
 492   TYPE_STUB_DECL (enumtype) = enumdecl;
 493
 494   tree value_chain = NULL_TREE;
 495   string_int_pair *value;
 496   unsigned int i;
 497   FOR_EACH_VEC_ELT (values, i, value)
 498     {
 499       tree value_decl = build_decl (loc, CONST_DECL,
 500                                     get_identifier (value->first), enumtype);
 501       DECL_INITIAL (value_decl) = build_int_cst (integer_type_node,
 502                                                  value->second);
 503       lang_hooks.decls.pushdecl (value_decl);
 504       value_chain = tree_cons (value_decl, DECL_INITIAL (value_decl),
 505                                value_chain);
 506     }
 507
 508   TYPE_MIN_VALUE (enumtype) = TYPE_MIN_VALUE (integer_type_node);
 509   TYPE_MAX_VALUE (enumtype) = TYPE_MAX_VALUE (integer_type_node);
 510   SET_TYPE_ALIGN (enumtype, TYPE_ALIGN (integer_type_node));
 511   TYPE_PRECISION (enumtype) = TYPE_PRECISION (integer_type_node);
 512   layout_type (enumtype);
 513   lang_hooks.decls.pushdecl (enumdecl);
 514
 515   return enumtype;
 516 }
 517
 518 /* Default implementation of LANG_HOOKS_TYPE_FOR_SIZE.
 519    Return an integer type with PRECISION bits of precision,
 520    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
 521
 522 tree
 523 lhd_type_for_size (unsigned precision, int unsignedp)
 524 {
 525   int i;
 526
 527   if (precision == TYPE_PRECISION (integer_type_node))
 528     return unsignedp ? unsigned_type_node : integer_type_node;
 529
 530   if (precision == TYPE_PRECISION (signed_char_type_node))
 531     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
 532
 533   if (precision == TYPE_PRECISION (short_integer_type_node))
 534     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
 535
 536   if (precision == TYPE_PRECISION (long_integer_type_node))
 537     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
 538
 539   if (precision == TYPE_PRECISION (long_long_integer_type_node))
 540     return unsignedp
 541            ? long_long_unsigned_type_node
 542            : long_long_integer_type_node;
 543
 544   for (i = 0; i < NUM_INT_N_ENTS; i ++)
 545     if (int_n_enabled_p[i]
 546         && precision == int_n_data[i].bitsize)
 547       return (unsignedp ? int_n_trees[i].unsigned_type
 548               : int_n_trees[i].signed_type);
 549
 550   if (precision <= TYPE_PRECISION (intQI_type_node))
 551     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
 552
 553   if (precision <= TYPE_PRECISION (intHI_type_node))
 554     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
 555
 556   if (precision <= TYPE_PRECISION (intSI_type_node))
 557     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
 558
 559   if (precision <= TYPE_PRECISION (intDI_type_node))
 560     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
 561
 562   if (precision <= TYPE_PRECISION (intTI_type_node))
 563     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
 564
 565   return NULL_TREE;
 566 }
 567
 568 HOST_WIDE_INT
 569 lhd_to_target_charset (HOST_WIDE_INT c)
 570 {
 571   return c;
 572 }
 573
 574 tree
 575 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 576 {
 577   return expr;
 578 }
 579
 580 /* Return sharing kind if OpenMP sharing attribute of DECL is
 581    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 582
 583 enum omp_clause_default_kind
 584 lhd_omp_predetermined_sharing (tree decl)
 585 {
 586   if (DECL_ARTIFICIAL (decl))
 587     return OMP_CLAUSE_DEFAULT_SHARED;
 588   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 589 }
 590
 591 /* Return sharing kind if OpenMP mapping attribute of DECL is
 592    predetermined, OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED otherwise.  */
 593
 594 enum omp_clause_defaultmap_kind
 595 lhd_omp_predetermined_mapping (tree decl)
 596 {
 597   if (DECL_ARTIFICIAL (decl))
 598     return OMP_CLAUSE_DEFAULTMAP_TO;
 599   return OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED;
 600 }
 601
 602 /* Generate code to copy SRC to DST.  */
 603
 604 tree
 605 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 606 {
 607   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 608 }
 609
 610 /* Finalize clause C.  */
 611
 612 void
 613 lhd_omp_finish_clause (tree, gimple_seq *, bool)
 614 {
 615 }
 616
 617 /* Return true if DECL is a scalar variable (for the purpose of
 618    implicit firstprivatization).  */
 619
 620 bool
 621 lhd_omp_scalar_p (tree decl)
 622 {
 623   tree type = TREE_TYPE (decl);
 624   if (TREE_CODE (type) == REFERENCE_TYPE)
 625     type = TREE_TYPE (type);
 626   if (TREE_CODE (type) == COMPLEX_TYPE)
 627     type = TREE_TYPE (type);
 628   if (INTEGRAL_TYPE_P (type)
 629       || SCALAR_FLOAT_TYPE_P (type)
 630       || TREE_CODE (type) == POINTER_TYPE)
 631     return true;
 632   return false;
 633 }
 634
 635 /* Register language specific type size variables as potentially OpenMP
 636    firstprivate variables.  */
 637
 638 void
 639 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 640                                    tree t ATTRIBUTE_UNUSED)
 641 {
 642 }
 643
 644 /* Return true if TYPE is an OpenMP mappable type.  */
 645
 646 bool
 647 lhd_omp_mappable_type (tree type)
 648 {
 649   /* Mappable type has to be complete.  */
 650   if (type == error_mark_node || !COMPLETE_TYPE_P (type))
 651     return false;
 652   return true;
 653 }
 654
 655 /* Common function for add_builtin_function, add_builtin_function_ext_scope
 656    and simulate_builtin_function_decl.  */
 657
 658 static tree
 659 build_builtin_function (location_t location, const char *name, tree type,
 660                         int function_code, enum built_in_class cl,
 661                         const char *library_name, tree attrs)
 662 {
 663   tree   id = get_identifier (name);
 664   tree decl = build_decl (location, FUNCTION_DECL, id, type);
 665
 666   TREE_PUBLIC (decl)         = 1;
 667   DECL_EXTERNAL (decl)       = 1;
 668
 669   set_decl_built_in_function (decl, cl, function_code);
 670
 671   if (library_name)
 672     {
 673       tree libname = get_identifier (library_name);
 674
 675       libname = targetm.mangle_decl_assembler_name (decl, libname);
 676       SET_DECL_ASSEMBLER_NAME (decl, libname);
 677     }
 678
 679   /* Possibly apply some default attributes to this built-in function.  */
 680   if (attrs)
 681     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 682   else
 683     decl_attributes (&decl, NULL_TREE, 0);
 684
 685   return decl;
 686 }
 687
 688 /* Create a builtin function.  */
 689
 690 tree
 691 add_builtin_function (const char *name,
 692                       tree type,
 693                       int function_code,
 694                       enum built_in_class cl,
 695                       const char *library_name,
 696                       tree attrs)
 697 {
 698   tree decl = build_builtin_function (BUILTINS_LOCATION, name, type,
 699                                       function_code, cl, library_name, attrs);
 700   return lang_hooks.builtin_function (decl);
 701 }
 702
 703 /* Like add_builtin_function, but make sure the scope is the external scope.
 704    This is used to delay putting in back end builtin functions until the ISA
 705    that defines the builtin is declared via function specific target options,
 706    which can save memory for machines like the x86_64 that have multiple ISAs.
 707    If this points to the same function as builtin_function, the backend must
 708    add all of the builtins at program initialization time.  */
 709
 710 tree
 711 add_builtin_function_ext_scope (const char *name,
 712                                 tree type,
 713                                 int function_code,
 714                                 enum built_in_class cl,
 715                                 const char *library_name,
 716                                 tree attrs)
 717 {
 718   tree decl = build_builtin_function (BUILTINS_LOCATION, name, type,
 719                                       function_code, cl, library_name, attrs);
 720   return lang_hooks.builtin_function_ext_scope (decl);
 721 }
 722
 723 /* Simulate a declaration of a target-specific built-in function at
 724    location LOCATION, as though it had been declared directly in the
 725    source language.  NAME is the name of the function, TYPE is its function
 726    type, FUNCTION_CODE is the target-specific function code, LIBRARY_NAME
 727    is the name of the underlying library function (NULL if none) and
 728    ATTRS is a list of function attributes.
 729
 730    Return the decl of the declared function.  */
 731
 732 tree
 733 simulate_builtin_function_decl (location_t location, const char *name,
 734                                 tree type, int function_code,
 735                                 const char *library_name, tree attrs)
 736 {
 737   tree decl = build_builtin_function (location, name, type,
 738                                       function_code, BUILT_IN_MD,
 739                                       library_name, attrs);
 740   tree new_decl = lang_hooks.simulate_builtin_function_decl (decl);
 741
 742   /* Give the front end a chance to create a new decl if necessary,
 743      but if the front end discards the decl in favour of a conflicting
 744      (erroneous) previous definition, return the decl that we tried but
 745      failed to add.  This allows the caller to process the returned decl
 746      normally, even though the source code won't be able to use it.  */
 747   if (TREE_CODE (new_decl) == FUNCTION_DECL
 748       && fndecl_built_in_p (new_decl, function_code, BUILT_IN_MD))
 749     return new_decl;
 750
 751   return decl;
 752 }
 753
 754 tree
 755 lhd_builtin_function (tree decl)
 756 {
 757   lang_hooks.decls.pushdecl (decl);
 758   return decl;
 759 }
 760
 761 /* Create a builtin type.  */
 762
 763 tree
 764 add_builtin_type (const char *name, tree type)
 765 {
 766   tree   id = get_identifier (name);
 767   tree decl = build_decl (BUILTINS_LOCATION, TYPE_DECL, id, type);
 768   return lang_hooks.decls.pushdecl (decl);
 769 }
 770
 771 /* LTO hooks.  */
 772
 773 /* Used to save and restore any previously active section.  */
 774 static section *saved_section;
 775
 776
 777 /* Begin a new LTO output section named NAME.  This default implementation
 778    saves the old section and emits assembly code to switch to the new
 779    section.  */
 780
 781 void
 782 lhd_begin_section (const char *name)
 783 {
 784   section *section;
 785
 786   /* Save the old section so we can restore it in lto_end_asm_section.  */
 787   gcc_assert (!saved_section);
 788   saved_section = in_section;
 789   if (!saved_section)
 790     saved_section = text_section;
 791
 792   /* Create a new section and switch to it.  */
 793   section = get_section (name, SECTION_DEBUG | SECTION_EXCLUDE, NULL);
 794   switch_to_section (section);
 795 }
 796
 797
 798 /* Write DATA of length LEN to the current LTO output section.  This default
 799    implementation just calls assemble_string.  */
 800
 801 void
 802 lhd_append_data (const void *data, size_t len, void *)
 803 {
 804   if (data)
 805     {
 806       timevar_push (TV_IPA_LTO_OUTPUT);
 807       assemble_string ((const char *)data, len);
 808       timevar_pop (TV_IPA_LTO_OUTPUT);
 809     }
 810 }
 811
 812
 813 /* Finish the current LTO output section.  This default implementation emits
 814    assembly code to switch to any section previously saved by
 815    lhd_begin_section.  */
 816
 817 void
 818 lhd_end_section (void)
 819 {
 820   if (saved_section)
 821     {
 822       switch_to_section (saved_section);
 823       saved_section = NULL;
 824     }
 825 }
 826
 827 /* Default implementation of enum_underlying_base_type using type_for_size.  */
 828
 829 tree
 830 lhd_enum_underlying_base_type (const_tree enum_type)
 831 {
 832   return lang_hooks.types.type_for_size (TYPE_PRECISION (enum_type),
 833                                          TYPE_UNSIGNED (enum_type));
 834 }
 835
 836 /* Default implementation of LANG_HOOKS_GET_SUBSTRING_LOCATION.  */
 837
 838 const char *
 839 lhd_get_substring_location (const substring_loc &, location_t *)
 840 {
 841   return "unimplemented";
 842 }
 843
 844 /* Default implementation of LANG_HOOKS_DECL_DWARF_ATTRIBUTE.  Don't add
 845    any attributes.  */
 846
 847 int
 848 lhd_decl_dwarf_attribute (const_tree, int)
 849 {
 850   return -1;
 851 }
 852
 853 /* Default implementation of LANG_HOOKS_TYPE_DWARF_ATTRIBUTE.  Don't add
 854    any attributes.  */
 855
 856 int
 857 lhd_type_dwarf_attribute (const_tree, int)
 858 {
 859   return -1;
 860 }
 861
 862 /* Default implementation of LANG_HOOKS_UNIT_SIZE_WITHOUT_REUSABLE_PADDING.
 863    Just return TYPE_SIZE_UNIT unadjusted.  */
 864
 865 tree
 866 lhd_unit_size_without_reusable_padding (tree t)
 867 {
 868   return TYPE_SIZE_UNIT (t);
 869 }
 870
 871 /* Default implementation for the finalize_early_debug hook.  */
 872
 873 void
 874 lhd_finalize_early_debug (void)
 875 {
 876   /* Emit early debug for reachable functions, and by consequence,
 877      locally scoped symbols.  */
 878   struct cgraph_node *cnode;
 879   FOR_EACH_FUNCTION_WITH_GIMPLE_BODY (cnode)
 880     (*debug_hooks->early_global_decl) (cnode->decl);
 881 }
 882
 883 /* Returns true if the current lang_hooks represents the GNU C frontend.  */
 884
 885 bool
 886 lang_GNU_C (void)
 887 {
 888   return (strncmp (lang_hooks.name, "GNU C", 5) == 0
 889           && (lang_hooks.name[5] == '\0' || ISDIGIT (lang_hooks.name[5])));
 890 }
 891
 892 /* Returns true if the current lang_hooks represents the GNU C++ frontend.  */
 893
 894 bool
 895 lang_GNU_CXX (void)
 896 {
 897   return strncmp (lang_hooks.name, "GNU C++", 7) == 0;
 898 }
 899
 900 /* Returns true if the current lang_hooks represents the GNU Fortran frontend.  */
 901
 902 bool
 903 lang_GNU_Fortran (void)
 904 {
 905   return strncmp (lang_hooks.name, "GNU Fortran", 11) == 0;
 906 }
 907
 908 /* Returns true if the current lang_hooks represents the GNU Objective-C
 909    frontend.  */
 910
 911 bool
 912 lang_GNU_OBJC (void)
 913 {
 914   return strncmp (lang_hooks.name, "GNU Objective-C", 15) == 0;
 915 }