gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright (C) 2001-2014 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 "intl.h"
  25 #include "tm.h"
  26 #include "toplev.h"
  27 #include "tree.h"
  28 #include "stringpool.h"
  29 #include "attribs.h"
  30 #include "tree-inline.h"
  31 #include "gimplify.h"
  32 #include "rtl.h"
  33 #include "insn-config.h"
  34 #include "flags.h"
  35 #include "langhooks.h"
  36 #include "target.h"
  37 #include "langhooks-def.h"
  38 #include "diagnostic.h"
  39 #include "tree-diagnostic.h"
  40 #include "cgraph.h"
  41 #include "timevar.h"
  42 #include "output.h"
  43
  44 /* Do nothing; in many cases the default hook.  */
  45
  46 void
  47 lhd_do_nothing (void)
  48 {
  49 }
  50
  51 /* Do nothing (tree).  */
  52
  53 void
  54 lhd_do_nothing_t (tree ARG_UNUSED (t))
  55 {
  56 }
  57
  58 /* Pass through (tree).  */
  59 tree
  60 lhd_pass_through_t (tree t)
  61 {
  62   return t;
  63 }
  64
  65 /* Do nothing (int, int, int).  Return NULL_TREE.  */
  66
  67 tree
  68 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  69                                      int ARG_UNUSED (j),
  70                                      int ARG_UNUSED (k))
  71 {
  72   return NULL_TREE;
  73 }
  74
  75 /* Do nothing (function).  */
  76
  77 void
  78 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  79 {
  80 }
  81
  82 /* Do nothing (return NULL_TREE).  */
  83
  84 tree
  85 lhd_return_null_tree_v (void)
  86 {
  87   return NULL_TREE;
  88 }
  89
  90 /* Do nothing (return NULL_TREE).  */
  91
  92 tree
  93 lhd_return_null_tree (tree ARG_UNUSED (t))
  94 {
  95   return NULL_TREE;
  96 }
  97
  98 /* Do nothing (return NULL_TREE).  */
  99
 100 tree
 101 lhd_return_null_const_tree (const_tree ARG_UNUSED (t))
 102 {
 103   return NULL_TREE;
 104 }
 105
 106 /* The default post options hook.  */
 107
 108 bool
 109 lhd_post_options (const char ** ARG_UNUSED (pfilename))
 110 {
 111   /* Excess precision other than "fast" requires front-end
 112      support.  */
 113   flag_excess_precision_cmdline = EXCESS_PRECISION_FAST;
 114   return false;
 115 }
 116
 117 /* Called from by print-tree.c.  */
 118
 119 void
 120 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 121                         tree ARG_UNUSED (node),
 122                         int ARG_UNUSED (indent))
 123 {
 124 }
 125
 126 /* Called from check_global_declarations.  */
 127
 128 bool
 129 lhd_warn_unused_global_decl (const_tree decl)
 130 {
 131   /* This is what used to exist in check_global_declarations.  Probably
 132      not many of these actually apply to non-C languages.  */
 133
 134   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 135     return false;
 136   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 137     return false;
 138   if (DECL_IN_SYSTEM_HEADER (decl))
 139     return false;
 140
 141   return true;
 142 }
 143
 144 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 145 void
 146 lhd_set_decl_assembler_name (tree decl)
 147 {
 148   tree id;
 149
 150   /* set_decl_assembler_name may be called on TYPE_DECL to record ODR
 151      name for C++ types.  By default types have no ODR names.  */
 152   if (TREE_CODE (decl) == TYPE_DECL)
 153     return;
 154
 155   /* The language-independent code should never use the
 156      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 157      VAR_DECLs for variables with static storage duration need a real
 158      DECL_ASSEMBLER_NAME.  */
 159   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 160               || (TREE_CODE (decl) == VAR_DECL
 161                   && (TREE_STATIC (decl)
 162                       || DECL_EXTERNAL (decl)
 163                       || TREE_PUBLIC (decl))));
 164
 165   /* By default, assume the name to use in assembly code is the same
 166      as that used in the source language.  (That's correct for C, and
 167      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 168      DECL_NAME in build_decl, so this choice provides backwards
 169      compatibility with existing front-ends.  This assumption is wrapped
 170      in a target hook, to allow for target-specific modification of the
 171      identifier.
 172
 173      Can't use just the variable's own name for a variable whose scope
 174      is less than the whole compilation.  Concatenate a distinguishing
 175      number - we use the DECL_UID.  */
 176
 177   if (TREE_PUBLIC (decl) || DECL_FILE_SCOPE_P (decl))
 178     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 179   else
 180     {
 181       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 182       char *label;
 183
 184       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 185       id = get_identifier (label);
 186     }
 187   SET_DECL_ASSEMBLER_NAME (decl, id);
 188
 189 }
 190
 191 /* Type promotion for variable arguments.  */
 192 tree
 193 lhd_type_promotes_to (tree ARG_UNUSED (type))
 194 {
 195   gcc_unreachable ();
 196 }
 197
 198 /* Registration of machine- or os-specific builtin types.  */
 199 void
 200 lhd_register_builtin_type (tree ARG_UNUSED (type),
 201                            const char * ARG_UNUSED (name))
 202 {
 203 }
 204
 205 /* Invalid use of an incomplete type.  */
 206 void
 207 lhd_incomplete_type_error (const_tree ARG_UNUSED (value), const_tree type)
 208 {
 209   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 210   return;
 211 }
 212
 213 /* Provide a default routine for alias sets that always returns -1.  This
 214    is used by languages that don't need to do anything special.  */
 215
 216 alias_set_type
 217 lhd_get_alias_set (tree ARG_UNUSED (t))
 218 {
 219   return -1;
 220 }
 221
 222 /* This is the default decl_printable_name function.  */
 223
 224 const char *
 225 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 226 {
 227   gcc_assert (decl && DECL_NAME (decl));
 228   return IDENTIFIER_POINTER (DECL_NAME (decl));
 229 }
 230
 231 /* This is the default dwarf_name function.  */
 232
 233 const char *
 234 lhd_dwarf_name (tree t, int verbosity)
 235 {
 236   gcc_assert (DECL_P (t));
 237
 238   return lang_hooks.decl_printable_name (t, verbosity);
 239 }
 240
 241 /* This compares two types for equivalence ("compatible" in C-based languages).
 242    This routine should only return 1 if it is sure.  It should not be used
 243    in contexts where erroneously returning 0 causes problems.  */
 244
 245 int
 246 lhd_types_compatible_p (tree x, tree y)
 247 {
 248   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 249 }
 250
 251 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 252    nodes.  Returns nonzero if it does not want the usual dumping of the
 253    second argument.  */
 254
 255 bool
 256 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 257 {
 258   return false;
 259 }
 260
 261 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 262    language-specific way.  */
 263
 264 int
 265 lhd_tree_dump_type_quals (const_tree t)
 266 {
 267   return TYPE_QUALS (t);
 268 }
 269
 270 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 271
 272 int
 273 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED,
 274                    gimple_seq *pre_p ATTRIBUTE_UNUSED,
 275                    gimple_seq *post_p ATTRIBUTE_UNUSED)
 276 {
 277   return GS_UNHANDLED;
 278 }
 279
 280 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 281    which is a language-specific tree code in category tcc_constant or
 282    tcc_exceptional.  The default expects never to be called.  */
 283 size_t
 284 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 285 {
 286   gcc_unreachable ();
 287 }
 288
 289 /* Return true if decl, which is a function decl, may be called by a
 290    sibcall.  */
 291
 292 bool
 293 lhd_decl_ok_for_sibcall (const_tree decl ATTRIBUTE_UNUSED)
 294 {
 295   return true;
 296 }
 297
 298 /* lang_hooks.decls.final_write_globals: perform final processing on
 299    global variables.  */
 300 void
 301 write_global_declarations (void)
 302 {
 303   tree globals, decl, *vec;
 304   int len, i;
 305
 306   timevar_start (TV_PHASE_DEFERRED);
 307   /* Really define vars that have had only a tentative definition.
 308      Really output inline functions that must actually be callable
 309      and have not been output so far.  */
 310
 311   globals = lang_hooks.decls.getdecls ();
 312   len = list_length (globals);
 313   vec = XNEWVEC (tree, len);
 314
 315   /* Process the decls in reverse order--earliest first.
 316      Put them into VEC from back to front, then take out from front.  */
 317
 318   for (i = 0, decl = globals; i < len; i++, decl = DECL_CHAIN (decl))
 319     vec[len - i - 1] = decl;
 320
 321   wrapup_global_declarations (vec, len);
 322   check_global_declarations (vec, len);
 323   timevar_stop (TV_PHASE_DEFERRED);
 324
 325   timevar_start (TV_PHASE_OPT_GEN);
 326   /* This lang hook is dual-purposed, and also finalizes the
 327      compilation unit.  */
 328   symtab->finalize_compilation_unit ();
 329   timevar_stop (TV_PHASE_OPT_GEN);
 330
 331   timevar_start (TV_PHASE_DBGINFO);
 332   emit_debug_global_declarations (vec, len);
 333   timevar_stop (TV_PHASE_DBGINFO);
 334
 335   /* Clean up.  */
 336   free (vec);
 337 }
 338
 339 /* Called to perform language-specific initialization of CTX.  */
 340 void
 341 lhd_initialize_diagnostics (diagnostic_context *ctx ATTRIBUTE_UNUSED)
 342 {
 343 }
 344
 345 /* Called to perform language-specific options initialization.  */
 346 void
 347 lhd_init_options (unsigned int decoded_options_count ATTRIBUTE_UNUSED,
 348                   struct cl_decoded_option *decoded_options ATTRIBUTE_UNUSED)
 349 {
 350 }
 351
 352 /* By default, always complain about options for the wrong language.  */
 353 bool
 354 lhd_complain_wrong_lang_p (const struct cl_option *option ATTRIBUTE_UNUSED)
 355 {
 356   return true;
 357 }
 358
 359 /* By default, no language-specific options are valid.  */
 360 bool
 361 lhd_handle_option (size_t code ATTRIBUTE_UNUSED,
 362                    const char *arg ATTRIBUTE_UNUSED,
 363                    int value ATTRIBUTE_UNUSED, int kind ATTRIBUTE_UNUSED,
 364                    location_t loc ATTRIBUTE_UNUSED,
 365                    const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 366 {
 367   return false;
 368 }
 369
 370 /* The default function to print out name of current function that caused
 371    an error.  */
 372 void
 373 lhd_print_error_function (diagnostic_context *context, const char *file,
 374                           diagnostic_info *diagnostic)
 375 {
 376   if (diagnostic_last_function_changed (context, diagnostic))
 377     {
 378       const char *old_prefix = context->printer->prefix;
 379       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 380       char *new_prefix = (file && abstract_origin == NULL)
 381                          ? file_name_as_prefix (context, file) : NULL;
 382
 383       pp_set_prefix (context->printer, new_prefix);
 384
 385       if (current_function_decl == NULL)
 386         pp_printf (context->printer, _("At top level:"));
 387       else
 388         {
 389           tree fndecl, ao;
 390
 391           if (abstract_origin)
 392             {
 393               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 394               while (TREE_CODE (ao) == BLOCK
 395                      && BLOCK_ABSTRACT_ORIGIN (ao)
 396                      && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 397                 ao = BLOCK_ABSTRACT_ORIGIN (ao);
 398               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 399               fndecl = ao;
 400             }
 401           else
 402             fndecl = current_function_decl;
 403
 404           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 405             pp_printf
 406               (context->printer, _("In member function %qs"),
 407                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 408           else
 409             pp_printf
 410               (context->printer, _("In function %qs"),
 411                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 412
 413           while (abstract_origin)
 414             {
 415               location_t *locus;
 416               tree block = abstract_origin;
 417
 418               locus = &BLOCK_SOURCE_LOCATION (block);
 419               fndecl = NULL;
 420               block = BLOCK_SUPERCONTEXT (block);
 421               while (block && TREE_CODE (block) == BLOCK
 422                      && BLOCK_ABSTRACT_ORIGIN (block))
 423                 {
 424                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 425
 426                   while (TREE_CODE (ao) == BLOCK
 427                          && BLOCK_ABSTRACT_ORIGIN (ao)
 428                          && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 429                     ao = BLOCK_ABSTRACT_ORIGIN (ao);
 430
 431                   if (TREE_CODE (ao) == FUNCTION_DECL)
 432                     {
 433                       fndecl = ao;
 434                       break;
 435                     }
 436                   else if (TREE_CODE (ao) != BLOCK)
 437                     break;
 438
 439                   block = BLOCK_SUPERCONTEXT (block);
 440                 }
 441               if (fndecl)
 442                 abstract_origin = block;
 443               else
 444                 {
 445                   while (block && TREE_CODE (block) == BLOCK)
 446                     block = BLOCK_SUPERCONTEXT (block);
 447
 448                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 449                     fndecl = block;
 450                   abstract_origin = NULL;
 451                 }
 452               if (fndecl)
 453                 {
 454                   expanded_location s = expand_location (*locus);
 455                   pp_comma (context->printer);
 456                   pp_newline (context->printer);
 457                   if (s.file != NULL)
 458                     {
 459                       if (context->show_column)
 460                         pp_printf (context->printer,
 461                                    _("    inlined from %qs at %r%s:%d:%d%R"),
 462                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 463                                    "locus", s.file, s.line, s.column);
 464                       else
 465                         pp_printf (context->printer,
 466                                    _("    inlined from %qs at %r%s:%d%R"),
 467                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 468                                    "locus", s.file, s.line);
 469
 470                     }
 471                   else
 472                     pp_printf (context->printer, _("    inlined from %qs"),
 473                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 474                 }
 475             }
 476           pp_colon (context->printer);
 477         }
 478
 479       diagnostic_set_last_function (context, diagnostic);
 480       pp_newline_and_flush (context->printer);
 481       context->printer->prefix = old_prefix;
 482       free ((char*) new_prefix);
 483     }
 484 }
 485
 486 tree
 487 lhd_make_node (enum tree_code code)
 488 {
 489   return make_node (code);
 490 }
 491
 492 HOST_WIDE_INT
 493 lhd_to_target_charset (HOST_WIDE_INT c)
 494 {
 495   return c;
 496 }
 497
 498 tree
 499 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 500 {
 501   return expr;
 502 }
 503
 504 /* Return sharing kind if OpenMP sharing attribute of DECL is
 505    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 506
 507 enum omp_clause_default_kind
 508 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 509 {
 510   if (DECL_ARTIFICIAL (decl))
 511     return OMP_CLAUSE_DEFAULT_SHARED;
 512   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 513 }
 514
 515 /* Generate code to copy SRC to DST.  */
 516
 517 tree
 518 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 519 {
 520   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 521 }
 522
 523 /* Finalize clause C.  */
 524
 525 void
 526 lhd_omp_finish_clause (tree, gimple_seq *)
 527 {
 528 }
 529
 530 /* Register language specific type size variables as potentially OpenMP
 531    firstprivate variables.  */
 532
 533 void
 534 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 535                                    tree t ATTRIBUTE_UNUSED)
 536 {
 537 }
 538
 539 /* Return true if TYPE is an OpenMP mappable type.  */
 540
 541 bool
 542 lhd_omp_mappable_type (tree type)
 543 {
 544   /* Mappable type has to be complete.  */
 545   if (type == error_mark_node || !COMPLETE_TYPE_P (type))
 546     return false;
 547   return true;
 548 }
 549
 550 /* Common function for add_builtin_function and
 551    add_builtin_function_ext_scope.  */
 552 static tree
 553 add_builtin_function_common (const char *name,
 554                              tree type,
 555                              int function_code,
 556                              enum built_in_class cl,
 557                              const char *library_name,
 558                              tree attrs,
 559                              tree (*hook) (tree))
 560 {
 561   tree   id = get_identifier (name);
 562   tree decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, id, type);
 563
 564   TREE_PUBLIC (decl)         = 1;
 565   DECL_EXTERNAL (decl)       = 1;
 566   DECL_BUILT_IN_CLASS (decl) = cl;
 567
 568   DECL_FUNCTION_CODE (decl)  = (enum built_in_function) function_code;
 569
 570   /* DECL_FUNCTION_CODE is a bitfield; verify that the value fits.  */
 571   gcc_assert (DECL_FUNCTION_CODE (decl) == function_code);
 572
 573   if (library_name)
 574     {
 575       tree libname = get_identifier (library_name);
 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     assemble_string ((const char *)data, len);
 676 }
 677
 678
 679 /* Finish the current LTO output section.  This default implementation emits
 680    assembly code to switch to any section previously saved by
 681    lhd_begin_section.  */
 682
 683 void
 684 lhd_end_section (void)
 685 {
 686   if (saved_section)
 687     {
 688       switch_to_section (saved_section);
 689       saved_section = NULL;
 690     }
 691 }
 692
 693 /* Default implementation of enum_underlying_base_type using type_for_size.  */
 694
 695 tree
 696 lhd_enum_underlying_base_type (const_tree enum_type)
 697 {
 698   return lang_hooks.types.type_for_size (TYPE_PRECISION (enum_type),
 699                                          TYPE_UNSIGNED (enum_type));
 700 }