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
  40 /* Do nothing; in many cases the default hook.  */
  41
  42 void
  43 lhd_do_nothing (void)
  44 {
  45 }
  46
  47 /* Do nothing (tree).  */
  48
  49 void
  50 lhd_do_nothing_t (tree ARG_UNUSED (t))
  51 {
  52 }
  53
  54 /* Pass through (tree).  */
  55 tree
  56 lhd_pass_through_t (tree t)
  57 {
  58   return t;
  59 }
  60
  61 /* Do nothing (int, int, int).  Return NULL_TREE.  */
  62
  63 tree
  64 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  65                                      int ARG_UNUSED (j),
  66                                      int ARG_UNUSED (k))
  67 {
  68   return NULL_TREE;
  69 }
  70
  71 /* Do nothing (function).  */
  72
  73 void
  74 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  75 {
  76 }
  77
  78 /* Do nothing (return NULL_TREE).  */
  79
  80 tree
  81 lhd_return_null_tree (tree ARG_UNUSED (t))
  82 {
  83   return NULL_TREE;
  84 }
  85
  86 /* Do nothing (return NULL_TREE).  */
  87
  88 tree
  89 lhd_return_null_const_tree (const_tree ARG_UNUSED (t))
  90 {
  91   return NULL_TREE;
  92 }
  93
  94 /* The default post options hook.  */
  95
  96 bool
  97 lhd_post_options (const char ** ARG_UNUSED (pfilename))
  98 {
  99   /* Excess precision other than "fast" requires front-end
 100      support.  */
 101   flag_excess_precision = EXCESS_PRECISION_FAST;
 102   return false;
 103 }
 104
 105 /* Called from by print-tree.c.  */
 106
 107 void
 108 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 109                         tree ARG_UNUSED (node),
 110                         int ARG_UNUSED (indent))
 111 {
 112 }
 113
 114 /* Called from check_global_declaration.  */
 115
 116 bool
 117 lhd_warn_unused_global_decl (const_tree decl)
 118 {
 119   /* This is what used to exist in check_global_declaration.  Probably
 120      not many of these actually apply to non-C languages.  */
 121
 122   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 123     return false;
 124   if (VAR_P (decl) && TREE_READONLY (decl))
 125     return false;
 126   if (DECL_IN_SYSTEM_HEADER (decl))
 127     return false;
 128
 129   return true;
 130 }
 131
 132 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 133 void
 134 lhd_set_decl_assembler_name (tree decl)
 135 {
 136   tree id;
 137
 138   /* set_decl_assembler_name may be called on TYPE_DECL to record ODR
 139      name for C++ types.  By default types have no ODR names.  */
 140   if (TREE_CODE (decl) == TYPE_DECL)
 141     return;
 142
 143   /* The language-independent code should never use the
 144      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 145      VAR_DECLs for variables with static storage duration need a real
 146      DECL_ASSEMBLER_NAME.  */
 147   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 148               || (VAR_P (decl)
 149                   && (TREE_STATIC (decl)
 150                       || DECL_EXTERNAL (decl)
 151                       || TREE_PUBLIC (decl))));
 152
 153   /* By default, assume the name to use in assembly code is the same
 154      as that used in the source language.  (That's correct for C, and
 155      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 156      DECL_NAME in build_decl, so this choice provides backwards
 157      compatibility with existing front-ends.  This assumption is wrapped
 158      in a target hook, to allow for target-specific modification of the
 159      identifier.
 160
 161      Can't use just the variable's own name for a variable whose scope
 162      is less than the whole compilation.  Concatenate a distinguishing
 163      number - we use the DECL_UID.  */
 164
 165   if (TREE_PUBLIC (decl) || DECL_FILE_SCOPE_P (decl))
 166     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 167   else
 168     {
 169       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 170       char *label;
 171
 172       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 173       id = get_identifier (label);
 174     }
 175
 176   SET_DECL_ASSEMBLER_NAME (decl, id);
 177 }
 178
 179 /* Forcibly overwrite the DECL_ASSEMBLER_NAME for DECL to NAME.  */
 180 void
 181 lhd_overwrite_decl_assembler_name (tree decl, tree name)
 182 {
 183   DECL_ASSEMBLER_NAME_RAW (decl) = name;
 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,
 278    tcc_exceptional or tcc_type.  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 register dumps.  */
 334 void
 335 lhd_register_dumps (gcc::dump_manager *)
 336 {
 337 }
 338
 339 /* Called to perform language-specific options initialization.  */
 340 void
 341 lhd_init_options (unsigned int decoded_options_count ATTRIBUTE_UNUSED,
 342                   struct cl_decoded_option *decoded_options ATTRIBUTE_UNUSED)
 343 {
 344 }
 345
 346 /* By default, always complain about options for the wrong language.  */
 347 bool
 348 lhd_complain_wrong_lang_p (const struct cl_option *option ATTRIBUTE_UNUSED)
 349 {
 350   return true;
 351 }
 352
 353 /* By default, no language-specific options are valid.  */
 354 bool
 355 lhd_handle_option (size_t code ATTRIBUTE_UNUSED,
 356                    const char *arg ATTRIBUTE_UNUSED,
 357                    HOST_WIDE_INT value ATTRIBUTE_UNUSED,
 358                    int kind ATTRIBUTE_UNUSED,
 359                    location_t loc ATTRIBUTE_UNUSED,
 360                    const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 361 {
 362   return false;
 363 }
 364
 365 /* The default function to print out name of current function that caused
 366    an error.  */
 367 void
 368 lhd_print_error_function (diagnostic_context *context, const char *file,
 369                           diagnostic_info *diagnostic)
 370 {
 371   if (diagnostic_last_function_changed (context, diagnostic))
 372     {
 373       char *old_prefix = pp_take_prefix (context->printer);
 374       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 375       char *new_prefix = (file && abstract_origin == NULL)
 376                          ? file_name_as_prefix (context, file) : NULL;
 377
 378       pp_set_prefix (context->printer, new_prefix);
 379
 380       if (current_function_decl == NULL)
 381         pp_printf (context->printer, _("At top level:"));
 382       else
 383         {
 384           tree fndecl, ao;
 385
 386           if (abstract_origin)
 387             {
 388               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 389               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 390               fndecl = ao;
 391             }
 392           else
 393             fndecl = current_function_decl;
 394
 395           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 396             pp_printf
 397               (context->printer, _("In member function %qs"),
 398                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 399           else
 400             pp_printf
 401               (context->printer, _("In function %qs"),
 402                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 403
 404           while (abstract_origin)
 405             {
 406               location_t *locus;
 407               tree block = abstract_origin;
 408
 409               locus = &BLOCK_SOURCE_LOCATION (block);
 410               fndecl = NULL;
 411               block = BLOCK_SUPERCONTEXT (block);
 412               while (block && TREE_CODE (block) == BLOCK
 413                      && BLOCK_ABSTRACT_ORIGIN (block))
 414                 {
 415                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 416                   if (TREE_CODE (ao) == FUNCTION_DECL)
 417                     {
 418                       fndecl = ao;
 419                       break;
 420                     }
 421                   else if (TREE_CODE (ao) != BLOCK)
 422                     break;
 423
 424                   block = BLOCK_SUPERCONTEXT (block);
 425                 }
 426               if (fndecl)
 427                 abstract_origin = block;
 428               else
 429                 {
 430                   while (block && TREE_CODE (block) == BLOCK)
 431                     block = BLOCK_SUPERCONTEXT (block);
 432
 433                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 434                     fndecl = block;
 435                   abstract_origin = NULL;
 436                 }
 437               if (fndecl)
 438                 {
 439                   expanded_location s = expand_location (*locus);
 440                   pp_comma (context->printer);
 441                   pp_newline (context->printer);
 442                   if (s.file != NULL)
 443                     {
 444                       if (context->show_column)
 445                         pp_printf (context->printer,
 446                                    _("    inlined from %qs at %r%s:%d:%d%R"),
 447                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 448                                    "locus", s.file, s.line, s.column);
 449                       else
 450                         pp_printf (context->printer,
 451                                    _("    inlined from %qs at %r%s:%d%R"),
 452                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 453                                    "locus", s.file, s.line);
 454
 455                     }
 456                   else
 457                     pp_printf (context->printer, _("    inlined from %qs"),
 458                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 459                 }
 460             }
 461           pp_colon (context->printer);
 462         }
 463
 464       diagnostic_set_last_function (context, diagnostic);
 465       pp_newline_and_flush (context->printer);
 466       context->printer->prefix = old_prefix;
 467       free ((char*) new_prefix);
 468     }
 469 }
 470
 471 tree
 472 lhd_make_node (enum tree_code code)
 473 {
 474   return make_node (code);
 475 }
 476
 477 /* Default implementation of LANG_HOOKS_SIMULATE_ENUM_DECL.  Assume a
 478    simple int-based enumerator (which is all the hook can be used for
 479    at present) and push each decl individually without any decoration.
 480
 481    This definition is suitable for LTO and is generic enough that it
 482    might be reusable elsewhere.  */
 483 tree
 484 lhd_simulate_enum_decl (location_t loc, const char *name,
 485                         vec<string_int_pair> values)
 486 {
 487   tree enumtype = lang_hooks.types.make_type (ENUMERAL_TYPE);
 488   tree enumdecl = build_decl (loc, TYPE_DECL, get_identifier (name), enumtype);
 489   TYPE_STUB_DECL (enumtype) = enumdecl;
 490
 491   tree value_chain = NULL_TREE;
 492   string_int_pair *value;
 493   unsigned int i;
 494   FOR_EACH_VEC_ELT (values, i, value)
 495     {
 496       tree value_decl = build_decl (loc, CONST_DECL,
 497                                     get_identifier (value->first), enumtype);
 498       DECL_INITIAL (value_decl) = build_int_cst (integer_type_node,
 499                                                  value->second);
 500       lang_hooks.decls.pushdecl (value_decl);
 501       value_chain = tree_cons (value_decl, DECL_INITIAL (value_decl),
 502                                value_chain);
 503     }
 504
 505   TYPE_MIN_VALUE (enumtype) = TYPE_MIN_VALUE (integer_type_node);
 506   TYPE_MAX_VALUE (enumtype) = TYPE_MAX_VALUE (integer_type_node);
 507   SET_TYPE_ALIGN (enumtype, TYPE_ALIGN (integer_type_node));
 508   TYPE_PRECISION (enumtype) = TYPE_PRECISION (integer_type_node);
 509   layout_type (enumtype);
 510   lang_hooks.decls.pushdecl (enumdecl);
 511
 512   return enumtype;
 513 }
 514
 515 /* Default implementation of LANG_HOOKS_TYPE_FOR_SIZE.
 516    Return an integer type with PRECISION bits of precision,
 517    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
 518
 519 tree
 520 lhd_type_for_size (unsigned precision, int unsignedp)
 521 {
 522   int i;
 523
 524   if (precision == TYPE_PRECISION (integer_type_node))
 525     return unsignedp ? unsigned_type_node : integer_type_node;
 526
 527   if (precision == TYPE_PRECISION (signed_char_type_node))
 528     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
 529
 530   if (precision == TYPE_PRECISION (short_integer_type_node))
 531     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
 532
 533   if (precision == TYPE_PRECISION (long_integer_type_node))
 534     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
 535
 536   if (precision == TYPE_PRECISION (long_long_integer_type_node))
 537     return unsignedp
 538            ? long_long_unsigned_type_node
 539            : long_long_integer_type_node;
 540
 541   for (i = 0; i < NUM_INT_N_ENTS; i ++)
 542     if (int_n_enabled_p[i]
 543         && precision == int_n_data[i].bitsize)
 544       return (unsignedp ? int_n_trees[i].unsigned_type
 545               : int_n_trees[i].signed_type);
 546
 547   if (precision <= TYPE_PRECISION (intQI_type_node))
 548     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
 549
 550   if (precision <= TYPE_PRECISION (intHI_type_node))
 551     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
 552
 553   if (precision <= TYPE_PRECISION (intSI_type_node))
 554     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
 555
 556   if (precision <= TYPE_PRECISION (intDI_type_node))
 557     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
 558
 559   if (precision <= TYPE_PRECISION (intTI_type_node))
 560     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
 561
 562   return NULL_TREE;
 563 }
 564
 565 HOST_WIDE_INT
 566 lhd_to_target_charset (HOST_WIDE_INT c)
 567 {
 568   return c;
 569 }
 570
 571 tree
 572 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 573 {
 574   return expr;
 575 }
 576
 577 /* Return sharing kind if OpenMP sharing attribute of DECL is
 578    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 579
 580 enum omp_clause_default_kind
 581 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 582 {
 583   if (DECL_ARTIFICIAL (decl))
 584     return OMP_CLAUSE_DEFAULT_SHARED;
 585   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 586 }
 587
 588 /* Generate code to copy SRC to DST.  */
 589
 590 tree
 591 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 592 {
 593   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 594 }
 595
 596 /* Finalize clause C.  */
 597
 598 void
 599 lhd_omp_finish_clause (tree, gimple_seq *)
 600 {
 601 }
 602
 603 /* Return true if DECL is a scalar variable (for the purpose of
 604    implicit firstprivatization).  */
 605
 606 bool
 607 lhd_omp_scalar_p (tree decl)
 608 {
 609   tree type = TREE_TYPE (decl);
 610   if (TREE_CODE (type) == REFERENCE_TYPE)
 611     type = TREE_TYPE (type);
 612   if (TREE_CODE (type) == COMPLEX_TYPE)
 613     type = TREE_TYPE (type);
 614   if (INTEGRAL_TYPE_P (type)
 615       || SCALAR_FLOAT_TYPE_P (type)
 616       || TREE_CODE (type) == POINTER_TYPE)
 617     return true;
 618   return false;
 619 }
 620
 621 /* Register language specific type size variables as potentially OpenMP
 622    firstprivate variables.  */
 623
 624 void
 625 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 626                                    tree t ATTRIBUTE_UNUSED)
 627 {
 628 }
 629
 630 /* Return true if TYPE is an OpenMP mappable type.  */
 631
 632 bool
 633 lhd_omp_mappable_type (tree type)
 634 {
 635   /* Mappable type has to be complete.  */
 636   if (type == error_mark_node || !COMPLETE_TYPE_P (type))
 637     return false;
 638   return true;
 639 }
 640
 641 /* Common function for add_builtin_function, add_builtin_function_ext_scope
 642    and simulate_builtin_function_decl.  */
 643
 644 static tree
 645 build_builtin_function (location_t location, const char *name, tree type,
 646                         int function_code, enum built_in_class cl,
 647                         const char *library_name, tree attrs)
 648 {
 649   tree   id = get_identifier (name);
 650   tree decl = build_decl (location, FUNCTION_DECL, id, type);
 651
 652   TREE_PUBLIC (decl)         = 1;
 653   DECL_EXTERNAL (decl)       = 1;
 654
 655   set_decl_built_in_function (decl, cl, function_code);
 656
 657   if (library_name)
 658     {
 659       tree libname = get_identifier (library_name);
 660
 661       libname = targetm.mangle_decl_assembler_name (decl, libname);
 662       SET_DECL_ASSEMBLER_NAME (decl, libname);
 663     }
 664
 665   /* Possibly apply some default attributes to this built-in function.  */
 666   if (attrs)
 667     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 668   else
 669     decl_attributes (&decl, NULL_TREE, 0);
 670
 671   return decl;
 672 }
 673
 674 /* Create a builtin function.  */
 675
 676 tree
 677 add_builtin_function (const char *name,
 678                       tree type,
 679                       int function_code,
 680                       enum built_in_class cl,
 681                       const char *library_name,
 682                       tree attrs)
 683 {
 684   tree decl = build_builtin_function (BUILTINS_LOCATION, name, type,
 685                                       function_code, cl, library_name, attrs);
 686   return lang_hooks.builtin_function (decl);
 687 }
 688
 689 /* Like add_builtin_function, but make sure the scope is the external scope.
 690    This is used to delay putting in back end builtin functions until the ISA
 691    that defines the builtin is declared via function specific target options,
 692    which can save memory for machines like the x86_64 that have multiple ISAs.
 693    If this points to the same function as builtin_function, the backend must
 694    add all of the builtins at program initialization time.  */
 695
 696 tree
 697 add_builtin_function_ext_scope (const char *name,
 698                                 tree type,
 699                                 int function_code,
 700                                 enum built_in_class cl,
 701                                 const char *library_name,
 702                                 tree attrs)
 703 {
 704   tree decl = build_builtin_function (BUILTINS_LOCATION, name, type,
 705                                       function_code, cl, library_name, attrs);
 706   return lang_hooks.builtin_function_ext_scope (decl);
 707 }
 708
 709 /* Simulate a declaration of a target-specific built-in function at
 710    location LOCATION, as though it had been declared directly in the
 711    source language.  NAME is the name of the function, TYPE is its function
 712    type, FUNCTION_CODE is the target-specific function code, LIBRARY_NAME
 713    is the name of the underlying library function (NULL if none) and
 714    ATTRS is a list of function attributes.
 715
 716    Return the decl of the declared function.  */
 717
 718 tree
 719 simulate_builtin_function_decl (location_t location, const char *name,
 720                                 tree type, int function_code,
 721                                 const char *library_name, tree attrs)
 722 {
 723   tree decl = build_builtin_function (location, name, type,
 724                                       function_code, BUILT_IN_MD,
 725                                       library_name, attrs);
 726   tree new_decl = lang_hooks.simulate_builtin_function_decl (decl);
 727
 728   /* Give the front end a chance to create a new decl if necessary,
 729      but if the front end discards the decl in favour of a conflicting
 730      (erroneous) previous definition, return the decl that we tried but
 731      failed to add.  This allows the caller to process the returned decl
 732      normally, even though the source code won't be able to use it.  */
 733   if (TREE_CODE (new_decl) == FUNCTION_DECL
 734       && fndecl_built_in_p (new_decl, function_code, BUILT_IN_MD))
 735     return new_decl;
 736
 737   return decl;
 738 }
 739
 740 tree
 741 lhd_builtin_function (tree decl)
 742 {
 743   lang_hooks.decls.pushdecl (decl);
 744   return decl;
 745 }
 746
 747 /* Create a builtin type.  */
 748
 749 tree
 750 add_builtin_type (const char *name, tree type)
 751 {
 752   tree   id = get_identifier (name);
 753   tree decl = build_decl (BUILTINS_LOCATION, TYPE_DECL, id, type);
 754   return lang_hooks.decls.pushdecl (decl);
 755 }
 756
 757 /* LTO hooks.  */
 758
 759 /* Used to save and restore any previously active section.  */
 760 static section *saved_section;
 761
 762
 763 /* Begin a new LTO output section named NAME.  This default implementation
 764    saves the old section and emits assembly code to switch to the new
 765    section.  */
 766
 767 void
 768 lhd_begin_section (const char *name)
 769 {
 770   section *section;
 771
 772   /* Save the old section so we can restore it in lto_end_asm_section.  */
 773   gcc_assert (!saved_section);
 774   saved_section = in_section;
 775   if (!saved_section)
 776     saved_section = text_section;
 777
 778   /* Create a new section and switch to it.  */
 779   section = get_section (name, SECTION_DEBUG | SECTION_EXCLUDE, NULL);
 780   switch_to_section (section);
 781 }
 782
 783
 784 /* Write DATA of length LEN to the current LTO output section.  This default
 785    implementation just calls assemble_string.  */
 786
 787 void
 788 lhd_append_data (const void *data, size_t len, void *)
 789 {
 790   if (data)
 791     {
 792       timevar_push (TV_IPA_LTO_OUTPUT);
 793       assemble_string ((const char *)data, len);
 794       timevar_pop (TV_IPA_LTO_OUTPUT);
 795     }
 796 }
 797
 798
 799 /* Finish the current LTO output section.  This default implementation emits
 800    assembly code to switch to any section previously saved by
 801    lhd_begin_section.  */
 802
 803 void
 804 lhd_end_section (void)
 805 {
 806   if (saved_section)
 807     {
 808       switch_to_section (saved_section);
 809       saved_section = NULL;
 810     }
 811 }
 812
 813 /* Default implementation of enum_underlying_base_type using type_for_size.  */
 814
 815 tree
 816 lhd_enum_underlying_base_type (const_tree enum_type)
 817 {
 818   return lang_hooks.types.type_for_size (TYPE_PRECISION (enum_type),
 819                                          TYPE_UNSIGNED (enum_type));
 820 }
 821
 822 /* Default implementation of LANG_HOOKS_GET_SUBSTRING_LOCATION.  */
 823
 824 const char *
 825 lhd_get_substring_location (const substring_loc &, location_t *)
 826 {
 827   return "unimplemented";
 828 }
 829
 830 /* Default implementation of LANG_HOOKS_DECL_DWARF_ATTRIBUTE.  Don't add
 831    any attributes.  */
 832
 833 int
 834 lhd_decl_dwarf_attribute (const_tree, int)
 835 {
 836   return -1;
 837 }
 838
 839 /* Default implementation of LANG_HOOKS_TYPE_DWARF_ATTRIBUTE.  Don't add
 840    any attributes.  */
 841
 842 int
 843 lhd_type_dwarf_attribute (const_tree, int)
 844 {
 845   return -1;
 846 }
 847
 848 /* Default implementation of LANG_HOOKS_UNIT_SIZE_WITHOUT_REUSABLE_PADDING.
 849    Just return TYPE_SIZE_UNIT unadjusted.  */
 850
 851 tree
 852 lhd_unit_size_without_reusable_padding (tree t)
 853 {
 854   return TYPE_SIZE_UNIT (t);
 855 }
 856
 857 /* Returns true if the current lang_hooks represents the GNU C frontend.  */
 858
 859 bool
 860 lang_GNU_C (void)
 861 {
 862   return (strncmp (lang_hooks.name, "GNU C", 5) == 0
 863           && (lang_hooks.name[5] == '\0' || ISDIGIT (lang_hooks.name[5])));
 864 }
 865
 866 /* Returns true if the current lang_hooks represents the GNU C++ frontend.  */
 867
 868 bool
 869 lang_GNU_CXX (void)
 870 {
 871   return strncmp (lang_hooks.name, "GNU C++", 7) == 0;
 872 }
 873
 874 /* Returns true if the current lang_hooks represents the GNU Fortran frontend.  */
 875
 876 bool
 877 lang_GNU_Fortran (void)
 878 {
 879   return strncmp (lang_hooks.name, "GNU Fortran", 11) == 0;
 880 }
 881
 882 /* Returns true if the current lang_hooks represents the GNU Objective-C
 883    frontend.  */
 884
 885 bool
 886 lang_GNU_OBJC (void)
 887 {
 888   return strncmp (lang_hooks.name, "GNU Objective-C", 15) == 0;
 889 }