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   /* The language-independent code should never use the
 151      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 152      VAR_DECLs for variables with static storage duration need a real
 153      DECL_ASSEMBLER_NAME.  */
 154   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 155               || (TREE_CODE (decl) == VAR_DECL
 156                   && (TREE_STATIC (decl)
 157                       || DECL_EXTERNAL (decl)
 158                       || TREE_PUBLIC (decl))));
 159
 160   /* By default, assume the name to use in assembly code is the same
 161      as that used in the source language.  (That's correct for C, and
 162      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 163      DECL_NAME in build_decl, so this choice provides backwards
 164      compatibility with existing front-ends.  This assumption is wrapped
 165      in a target hook, to allow for target-specific modification of the
 166      identifier.
 167
 168      Can't use just the variable's own name for a variable whose scope
 169      is less than the whole compilation.  Concatenate a distinguishing
 170      number - we use the DECL_UID.  */
 171
 172   if (TREE_PUBLIC (decl) || DECL_FILE_SCOPE_P (decl))
 173     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 174   else
 175     {
 176       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 177       char *label;
 178
 179       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 180       id = get_identifier (label);
 181     }
 182   SET_DECL_ASSEMBLER_NAME (decl, id);
 183
 184 }
 185
 186 /* Type promotion for variable arguments.  */
 187 tree
 188 lhd_type_promotes_to (tree ARG_UNUSED (type))
 189 {
 190   gcc_unreachable ();
 191 }
 192
 193 /* Registration of machine- or os-specific builtin types.  */
 194 void
 195 lhd_register_builtin_type (tree ARG_UNUSED (type),
 196                            const char * ARG_UNUSED (name))
 197 {
 198 }
 199
 200 /* Invalid use of an incomplete type.  */
 201 void
 202 lhd_incomplete_type_error (const_tree ARG_UNUSED (value), const_tree type)
 203 {
 204   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 205   return;
 206 }
 207
 208 /* Provide a default routine for alias sets that always returns -1.  This
 209    is used by languages that don't need to do anything special.  */
 210
 211 alias_set_type
 212 lhd_get_alias_set (tree ARG_UNUSED (t))
 213 {
 214   return -1;
 215 }
 216
 217 /* This is the default decl_printable_name function.  */
 218
 219 const char *
 220 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 221 {
 222   gcc_assert (decl && DECL_NAME (decl));
 223   return IDENTIFIER_POINTER (DECL_NAME (decl));
 224 }
 225
 226 /* This is the default dwarf_name function.  */
 227
 228 const char *
 229 lhd_dwarf_name (tree t, int verbosity)
 230 {
 231   gcc_assert (DECL_P (t));
 232
 233   return lang_hooks.decl_printable_name (t, verbosity);
 234 }
 235
 236 /* This compares two types for equivalence ("compatible" in C-based languages).
 237    This routine should only return 1 if it is sure.  It should not be used
 238    in contexts where erroneously returning 0 causes problems.  */
 239
 240 int
 241 lhd_types_compatible_p (tree x, tree y)
 242 {
 243   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 244 }
 245
 246 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 247    nodes.  Returns nonzero if it does not want the usual dumping of the
 248    second argument.  */
 249
 250 bool
 251 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 252 {
 253   return false;
 254 }
 255
 256 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 257    language-specific way.  */
 258
 259 int
 260 lhd_tree_dump_type_quals (const_tree t)
 261 {
 262   return TYPE_QUALS (t);
 263 }
 264
 265 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 266
 267 int
 268 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED,
 269                    gimple_seq *pre_p ATTRIBUTE_UNUSED,
 270                    gimple_seq *post_p ATTRIBUTE_UNUSED)
 271 {
 272   return GS_UNHANDLED;
 273 }
 274
 275 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 276    which is a language-specific tree code in category tcc_constant or
 277    tcc_exceptional.  The default expects never to be called.  */
 278 size_t
 279 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 280 {
 281   gcc_unreachable ();
 282 }
 283
 284 /* Return true if decl, which is a function decl, may be called by a
 285    sibcall.  */
 286
 287 bool
 288 lhd_decl_ok_for_sibcall (const_tree decl ATTRIBUTE_UNUSED)
 289 {
 290   return true;
 291 }
 292
 293 /* lang_hooks.decls.final_write_globals: perform final processing on
 294    global variables.  */
 295 void
 296 write_global_declarations (void)
 297 {
 298   tree globals, decl, *vec;
 299   int len, i;
 300
 301   timevar_start (TV_PHASE_DEFERRED);
 302   /* Really define vars that have had only a tentative definition.
 303      Really output inline functions that must actually be callable
 304      and have not been output so far.  */
 305
 306   globals = lang_hooks.decls.getdecls ();
 307   len = list_length (globals);
 308   vec = XNEWVEC (tree, len);
 309
 310   /* Process the decls in reverse order--earliest first.
 311      Put them into VEC from back to front, then take out from front.  */
 312
 313   for (i = 0, decl = globals; i < len; i++, decl = DECL_CHAIN (decl))
 314     vec[len - i - 1] = decl;
 315
 316   wrapup_global_declarations (vec, len);
 317   check_global_declarations (vec, len);
 318   timevar_stop (TV_PHASE_DEFERRED);
 319
 320   timevar_start (TV_PHASE_OPT_GEN);
 321   /* This lang hook is dual-purposed, and also finalizes the
 322      compilation unit.  */
 323   finalize_compilation_unit ();
 324   timevar_stop (TV_PHASE_OPT_GEN);
 325
 326   timevar_start (TV_PHASE_DBGINFO);
 327   emit_debug_global_declarations (vec, len);
 328   timevar_stop (TV_PHASE_DBGINFO);
 329
 330   /* Clean up.  */
 331   free (vec);
 332 }
 333
 334 /* Called to perform language-specific initialization of CTX.  */
 335 void
 336 lhd_initialize_diagnostics (diagnostic_context *ctx ATTRIBUTE_UNUSED)
 337 {
 338 }
 339
 340 /* Called to perform language-specific options initialization.  */
 341 void
 342 lhd_init_options (unsigned int decoded_options_count ATTRIBUTE_UNUSED,
 343                   struct cl_decoded_option *decoded_options ATTRIBUTE_UNUSED)
 344 {
 345 }
 346
 347 /* By default, always complain about options for the wrong language.  */
 348 bool
 349 lhd_complain_wrong_lang_p (const struct cl_option *option ATTRIBUTE_UNUSED)
 350 {
 351   return true;
 352 }
 353
 354 /* By default, no language-specific options are valid.  */
 355 bool
 356 lhd_handle_option (size_t code ATTRIBUTE_UNUSED,
 357                    const char *arg ATTRIBUTE_UNUSED,
 358                    int value ATTRIBUTE_UNUSED, 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       const char *old_prefix = context->printer->prefix;
 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               while (TREE_CODE (ao) == BLOCK
 390                      && BLOCK_ABSTRACT_ORIGIN (ao)
 391                      && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 392                 ao = BLOCK_ABSTRACT_ORIGIN (ao);
 393               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 394               fndecl = ao;
 395             }
 396           else
 397             fndecl = current_function_decl;
 398
 399           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 400             pp_printf
 401               (context->printer, _("In member function %qs"),
 402                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 403           else
 404             pp_printf
 405               (context->printer, _("In function %qs"),
 406                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 407
 408           while (abstract_origin)
 409             {
 410               location_t *locus;
 411               tree block = abstract_origin;
 412
 413               locus = &BLOCK_SOURCE_LOCATION (block);
 414               fndecl = NULL;
 415               block = BLOCK_SUPERCONTEXT (block);
 416               while (block && TREE_CODE (block) == BLOCK
 417                      && BLOCK_ABSTRACT_ORIGIN (block))
 418                 {
 419                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 420
 421                   while (TREE_CODE (ao) == BLOCK
 422                          && BLOCK_ABSTRACT_ORIGIN (ao)
 423                          && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 424                     ao = BLOCK_ABSTRACT_ORIGIN (ao);
 425
 426                   if (TREE_CODE (ao) == FUNCTION_DECL)
 427                     {
 428                       fndecl = ao;
 429                       break;
 430                     }
 431                   else if (TREE_CODE (ao) != BLOCK)
 432                     break;
 433
 434                   block = BLOCK_SUPERCONTEXT (block);
 435                 }
 436               if (fndecl)
 437                 abstract_origin = block;
 438               else
 439                 {
 440                   while (block && TREE_CODE (block) == BLOCK)
 441                     block = BLOCK_SUPERCONTEXT (block);
 442
 443                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 444                     fndecl = block;
 445                   abstract_origin = NULL;
 446                 }
 447               if (fndecl)
 448                 {
 449                   expanded_location s = expand_location (*locus);
 450                   pp_comma (context->printer);
 451                   pp_newline (context->printer);
 452                   if (s.file != NULL)
 453                     {
 454                       if (context->show_column)
 455                         pp_printf (context->printer,
 456                                    _("    inlined from %qs at %r%s:%d:%d%R"),
 457                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 458                                    "locus", s.file, s.line, s.column);
 459                       else
 460                         pp_printf (context->printer,
 461                                    _("    inlined from %qs at %r%s:%d%R"),
 462                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 463                                    "locus", s.file, s.line);
 464
 465                     }
 466                   else
 467                     pp_printf (context->printer, _("    inlined from %qs"),
 468                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 469                 }
 470             }
 471           pp_colon (context->printer);
 472         }
 473
 474       diagnostic_set_last_function (context, diagnostic);
 475       pp_newline_and_flush (context->printer);
 476       context->printer->prefix = old_prefix;
 477       free ((char*) new_prefix);
 478     }
 479 }
 480
 481 tree
 482 lhd_make_node (enum tree_code code)
 483 {
 484   return make_node (code);
 485 }
 486
 487 HOST_WIDE_INT
 488 lhd_to_target_charset (HOST_WIDE_INT c)
 489 {
 490   return c;
 491 }
 492
 493 tree
 494 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 495 {
 496   return expr;
 497 }
 498
 499 /* Return sharing kind if OpenMP sharing attribute of DECL is
 500    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 501
 502 enum omp_clause_default_kind
 503 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 504 {
 505   if (DECL_ARTIFICIAL (decl))
 506     return OMP_CLAUSE_DEFAULT_SHARED;
 507   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 508 }
 509
 510 /* Generate code to copy SRC to DST.  */
 511
 512 tree
 513 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 514 {
 515   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 516 }
 517
 518 /* Finalize clause C.  */
 519
 520 void
 521 lhd_omp_finish_clause (tree, gimple_seq *)
 522 {
 523 }
 524
 525 /* Register language specific type size variables as potentially OpenMP
 526    firstprivate variables.  */
 527
 528 void
 529 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 530                                    tree t ATTRIBUTE_UNUSED)
 531 {
 532 }
 533
 534 /* Return true if TYPE is an OpenMP mappable type.  */
 535
 536 bool
 537 lhd_omp_mappable_type (tree type)
 538 {
 539   /* Mappable type has to be complete.  */
 540   if (type == error_mark_node || !COMPLETE_TYPE_P (type))
 541     return false;
 542   return true;
 543 }
 544
 545 /* Common function for add_builtin_function and
 546    add_builtin_function_ext_scope.  */
 547 static tree
 548 add_builtin_function_common (const char *name,
 549                              tree type,
 550                              int function_code,
 551                              enum built_in_class cl,
 552                              const char *library_name,
 553                              tree attrs,
 554                              tree (*hook) (tree))
 555 {
 556   tree   id = get_identifier (name);
 557   tree decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, id, type);
 558
 559   TREE_PUBLIC (decl)         = 1;
 560   DECL_EXTERNAL (decl)       = 1;
 561   DECL_BUILT_IN_CLASS (decl) = cl;
 562
 563   DECL_FUNCTION_CODE (decl)  = (enum built_in_function) function_code;
 564
 565   /* DECL_FUNCTION_CODE is a bitfield; verify that the value fits.  */
 566   gcc_assert (DECL_FUNCTION_CODE (decl) == function_code);
 567
 568   if (library_name)
 569     {
 570       tree libname = get_identifier (library_name);
 571       SET_DECL_ASSEMBLER_NAME (decl, libname);
 572     }
 573
 574   /* Possibly apply some default attributes to this built-in function.  */
 575   if (attrs)
 576     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 577   else
 578     decl_attributes (&decl, NULL_TREE, 0);
 579
 580   return hook (decl);
 581
 582 }
 583
 584 /* Create a builtin function.  */
 585
 586 tree
 587 add_builtin_function (const char *name,
 588                       tree type,
 589                       int function_code,
 590                       enum built_in_class cl,
 591                       const char *library_name,
 592                       tree attrs)
 593 {
 594   return add_builtin_function_common (name, type, function_code, cl,
 595                                       library_name, attrs,
 596                                       lang_hooks.builtin_function);
 597 }
 598
 599 /* Like add_builtin_function, but make sure the scope is the external scope.
 600    This is used to delay putting in back end builtin functions until the ISA
 601    that defines the builtin is declared via function specific target options,
 602    which can save memory for machines like the x86_64 that have multiple ISAs.
 603    If this points to the same function as builtin_function, the backend must
 604    add all of the builtins at program initialization time.  */
 605
 606 tree
 607 add_builtin_function_ext_scope (const char *name,
 608                                 tree type,
 609                                 int function_code,
 610                                 enum built_in_class cl,
 611                                 const char *library_name,
 612                                 tree attrs)
 613 {
 614   return add_builtin_function_common (name, type, function_code, cl,
 615                                       library_name, attrs,
 616                                       lang_hooks.builtin_function_ext_scope);
 617 }
 618
 619 tree
 620 lhd_builtin_function (tree decl)
 621 {
 622   lang_hooks.decls.pushdecl (decl);
 623   return decl;
 624 }
 625
 626 /* Create a builtin type.  */
 627
 628 tree
 629 add_builtin_type (const char *name, tree type)
 630 {
 631   tree   id = get_identifier (name);
 632   tree decl = build_decl (BUILTINS_LOCATION, TYPE_DECL, id, type);
 633   return lang_hooks.decls.pushdecl (decl);
 634 }
 635
 636 /* LTO hooks.  */
 637
 638 /* Used to save and restore any previously active section.  */
 639 static section *saved_section;
 640
 641
 642 /* Begin a new LTO output section named NAME.  This default implementation
 643    saves the old section and emits assembly code to switch to the new
 644    section.  */
 645
 646 void
 647 lhd_begin_section (const char *name)
 648 {
 649   section *section;
 650
 651   /* Save the old section so we can restore it in lto_end_asm_section.  */
 652   gcc_assert (!saved_section);
 653   saved_section = in_section;
 654   if (!saved_section)
 655     saved_section = text_section;
 656
 657   /* Create a new section and switch to it.  */
 658   section = get_section (name, SECTION_DEBUG, NULL);
 659   switch_to_section (section);
 660 }
 661
 662
 663 /* Write DATA of length LEN to the current LTO output section.  This default
 664    implementation just calls assemble_string.  */
 665
 666 void
 667 lhd_append_data (const void *data, size_t len, void *)
 668 {
 669   if (data)
 670     assemble_string ((const char *)data, len);
 671 }
 672
 673
 674 /* Finish the current LTO output section.  This default implementation emits
 675    assembly code to switch to any section previously saved by
 676    lhd_begin_section.  */
 677
 678 void
 679 lhd_end_section (void)
 680 {
 681   if (saved_section)
 682     {
 683       switch_to_section (saved_section);
 684       saved_section = NULL;
 685     }
 686 }
 687
 688 /* Default implementation of enum_underlying_base_type using type_for_size.  */
 689
 690 tree
 691 lhd_enum_underlying_base_type (const_tree enum_type)
 692 {
 693   return lang_hooks.types.type_for_size (TYPE_PRECISION (enum_type),
 694                                          TYPE_UNSIGNED (enum_type));
 695 }