gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright (C) 2001-2013 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 "gimple.h"
  32 #include "gimplify.h"
  33 #include "rtl.h"
  34 #include "insn-config.h"
  35 #include "flags.h"
  36 #include "langhooks.h"
  37 #include "target.h"
  38 #include "langhooks-def.h"
  39 #include "ggc.h"
  40 #include "diagnostic.h"
  41 #include "tree-diagnostic.h"
  42 #include "cgraph.h"
  43 #include "timevar.h"
  44 #include "output.h"
  45
  46 /* Do nothing; in many cases the default hook.  */
  47
  48 void
  49 lhd_do_nothing (void)
  50 {
  51 }
  52
  53 /* Do nothing (tree).  */
  54
  55 void
  56 lhd_do_nothing_t (tree ARG_UNUSED (t))
  57 {
  58 }
  59
  60 /* Pass through (tree).  */
  61 tree
  62 lhd_pass_through_t (tree t)
  63 {
  64   return t;
  65 }
  66
  67 /* Do nothing (int, int, int).  Return NULL_TREE.  */
  68
  69 tree
  70 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  71                                      int ARG_UNUSED (j),
  72                                      int ARG_UNUSED (k))
  73 {
  74   return NULL_TREE;
  75 }
  76
  77 /* Do nothing (function).  */
  78
  79 void
  80 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  81 {
  82 }
  83
  84 /* Do nothing (return NULL_TREE).  */
  85
  86 tree
  87 lhd_return_null_tree_v (void)
  88 {
  89   return NULL_TREE;
  90 }
  91
  92 /* Do nothing (return NULL_TREE).  */
  93
  94 tree
  95 lhd_return_null_tree (tree ARG_UNUSED (t))
  96 {
  97   return NULL_TREE;
  98 }
  99
 100 /* Do nothing (return NULL_TREE).  */
 101
 102 tree
 103 lhd_return_null_const_tree (const_tree ARG_UNUSED (t))
 104 {
 105   return NULL_TREE;
 106 }
 107
 108 /* The default post options hook.  */
 109
 110 bool
 111 lhd_post_options (const char ** ARG_UNUSED (pfilename))
 112 {
 113   /* Excess precision other than "fast" requires front-end
 114      support.  */
 115   flag_excess_precision_cmdline = EXCESS_PRECISION_FAST;
 116   return false;
 117 }
 118
 119 /* Called from by print-tree.c.  */
 120
 121 void
 122 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 123                         tree ARG_UNUSED (node),
 124                         int ARG_UNUSED (indent))
 125 {
 126 }
 127
 128 /* Called from check_global_declarations.  */
 129
 130 bool
 131 lhd_warn_unused_global_decl (const_tree decl)
 132 {
 133   /* This is what used to exist in check_global_declarations.  Probably
 134      not many of these actually apply to non-C languages.  */
 135
 136   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 137     return false;
 138   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 139     return false;
 140   if (DECL_IN_SYSTEM_HEADER (decl))
 141     return false;
 142
 143   return true;
 144 }
 145
 146 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 147 void
 148 lhd_set_decl_assembler_name (tree decl)
 149 {
 150   tree id;
 151
 152   /* The language-independent code should never use the
 153      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 154      VAR_DECLs for variables with static storage duration need a real
 155      DECL_ASSEMBLER_NAME.  */
 156   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 157               || (TREE_CODE (decl) == VAR_DECL
 158                   && (TREE_STATIC (decl)
 159                       || DECL_EXTERNAL (decl)
 160                       || TREE_PUBLIC (decl))));
 161
 162   /* By default, assume the name to use in assembly code is the same
 163      as that used in the source language.  (That's correct for C, and
 164      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 165      DECL_NAME in build_decl, so this choice provides backwards
 166      compatibility with existing front-ends.  This assumption is wrapped
 167      in a target hook, to allow for target-specific modification of the
 168      identifier.
 169
 170      Can't use just the variable's own name for a variable whose scope
 171      is less than the whole compilation.  Concatenate a distinguishing
 172      number - we use the DECL_UID.  */
 173
 174   if (TREE_PUBLIC (decl) || DECL_FILE_SCOPE_P (decl))
 175     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 176   else
 177     {
 178       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 179       char *label;
 180
 181       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 182       id = get_identifier (label);
 183     }
 184   SET_DECL_ASSEMBLER_NAME (decl, id);
 185
 186 }
 187
 188 /* Type promotion for variable arguments.  */
 189 tree
 190 lhd_type_promotes_to (tree ARG_UNUSED (type))
 191 {
 192   gcc_unreachable ();
 193 }
 194
 195 /* Registration of machine- or os-specific builtin types.  */
 196 void
 197 lhd_register_builtin_type (tree ARG_UNUSED (type),
 198                            const char * ARG_UNUSED (name))
 199 {
 200 }
 201
 202 /* Invalid use of an incomplete type.  */
 203 void
 204 lhd_incomplete_type_error (const_tree ARG_UNUSED (value), const_tree type)
 205 {
 206   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 207   return;
 208 }
 209
 210 /* Provide a default routine for alias sets that always returns -1.  This
 211    is used by languages that don't need to do anything special.  */
 212
 213 alias_set_type
 214 lhd_get_alias_set (tree ARG_UNUSED (t))
 215 {
 216   return -1;
 217 }
 218
 219 /* This is the default decl_printable_name function.  */
 220
 221 const char *
 222 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 223 {
 224   gcc_assert (decl && DECL_NAME (decl));
 225   return IDENTIFIER_POINTER (DECL_NAME (decl));
 226 }
 227
 228 /* This is the default dwarf_name function.  */
 229
 230 const char *
 231 lhd_dwarf_name (tree t, int verbosity)
 232 {
 233   gcc_assert (DECL_P (t));
 234
 235   return lang_hooks.decl_printable_name (t, verbosity);
 236 }
 237
 238 /* This compares two types for equivalence ("compatible" in C-based languages).
 239    This routine should only return 1 if it is sure.  It should not be used
 240    in contexts where erroneously returning 0 causes problems.  */
 241
 242 int
 243 lhd_types_compatible_p (tree x, tree y)
 244 {
 245   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 246 }
 247
 248 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 249    nodes.  Returns nonzero if it does not want the usual dumping of the
 250    second argument.  */
 251
 252 bool
 253 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 254 {
 255   return false;
 256 }
 257
 258 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 259    language-specific way.  */
 260
 261 int
 262 lhd_tree_dump_type_quals (const_tree t)
 263 {
 264   return TYPE_QUALS (t);
 265 }
 266
 267 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 268
 269 int
 270 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED,
 271                    gimple_seq *pre_p ATTRIBUTE_UNUSED,
 272                    gimple_seq *post_p ATTRIBUTE_UNUSED)
 273 {
 274   return GS_UNHANDLED;
 275 }
 276
 277 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 278    which is a language-specific tree code in category tcc_constant or
 279    tcc_exceptional.  The default expects never to be called.  */
 280 size_t
 281 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 282 {
 283   gcc_unreachable ();
 284 }
 285
 286 /* Return true if decl, which is a function decl, may be called by a
 287    sibcall.  */
 288
 289 bool
 290 lhd_decl_ok_for_sibcall (const_tree decl ATTRIBUTE_UNUSED)
 291 {
 292   return true;
 293 }
 294
 295 /* lang_hooks.decls.final_write_globals: perform final processing on
 296    global variables.  */
 297 void
 298 write_global_declarations (void)
 299 {
 300   tree globals, decl, *vec;
 301   int len, i;
 302
 303   timevar_start (TV_PHASE_DEFERRED);
 304   /* Really define vars that have had only a tentative definition.
 305      Really output inline functions that must actually be callable
 306      and have not been output so far.  */
 307
 308   globals = lang_hooks.decls.getdecls ();
 309   len = list_length (globals);
 310   vec = XNEWVEC (tree, len);
 311
 312   /* Process the decls in reverse order--earliest first.
 313      Put them into VEC from back to front, then take out from front.  */
 314
 315   for (i = 0, decl = globals; i < len; i++, decl = DECL_CHAIN (decl))
 316     vec[len - i - 1] = decl;
 317
 318   wrapup_global_declarations (vec, len);
 319   check_global_declarations (vec, len);
 320   timevar_stop (TV_PHASE_DEFERRED);
 321
 322   timevar_start (TV_PHASE_OPT_GEN);
 323   /* This lang hook is dual-purposed, and also finalizes the
 324      compilation unit.  */
 325   finalize_compilation_unit ();
 326   timevar_stop (TV_PHASE_OPT_GEN);
 327
 328   timevar_start (TV_PHASE_DBGINFO);
 329   emit_debug_global_declarations (vec, len);
 330   timevar_stop (TV_PHASE_DBGINFO);
 331
 332   /* Clean up.  */
 333   free (vec);
 334 }
 335
 336 /* Called to perform language-specific initialization of CTX.  */
 337 void
 338 lhd_initialize_diagnostics (diagnostic_context *ctx ATTRIBUTE_UNUSED)
 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                    int value ATTRIBUTE_UNUSED, int kind ATTRIBUTE_UNUSED,
 361                    location_t loc ATTRIBUTE_UNUSED,
 362                    const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 363 {
 364   return false;
 365 }
 366
 367 /* The default function to print out name of current function that caused
 368    an error.  */
 369 void
 370 lhd_print_error_function (diagnostic_context *context, const char *file,
 371                           diagnostic_info *diagnostic)
 372 {
 373   if (diagnostic_last_function_changed (context, diagnostic))
 374     {
 375       const char *old_prefix = context->printer->prefix;
 376       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 377       char *new_prefix = (file && abstract_origin == NULL)
 378                          ? file_name_as_prefix (context, file) : NULL;
 379
 380       pp_set_prefix (context->printer, new_prefix);
 381
 382       if (current_function_decl == NULL)
 383         pp_printf (context->printer, _("At top level:"));
 384       else
 385         {
 386           tree fndecl, ao;
 387
 388           if (abstract_origin)
 389             {
 390               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 391               while (TREE_CODE (ao) == BLOCK
 392                      && BLOCK_ABSTRACT_ORIGIN (ao)
 393                      && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 394                 ao = BLOCK_ABSTRACT_ORIGIN (ao);
 395               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 396               fndecl = ao;
 397             }
 398           else
 399             fndecl = current_function_decl;
 400
 401           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 402             pp_printf
 403               (context->printer, _("In member function %qs"),
 404                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 405           else
 406             pp_printf
 407               (context->printer, _("In function %qs"),
 408                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 409
 410           while (abstract_origin)
 411             {
 412               location_t *locus;
 413               tree block = abstract_origin;
 414
 415               locus = &BLOCK_SOURCE_LOCATION (block);
 416               fndecl = NULL;
 417               block = BLOCK_SUPERCONTEXT (block);
 418               while (block && TREE_CODE (block) == BLOCK
 419                      && BLOCK_ABSTRACT_ORIGIN (block))
 420                 {
 421                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 422
 423                   while (TREE_CODE (ao) == BLOCK
 424                          && BLOCK_ABSTRACT_ORIGIN (ao)
 425                          && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 426                     ao = BLOCK_ABSTRACT_ORIGIN (ao);
 427
 428                   if (TREE_CODE (ao) == FUNCTION_DECL)
 429                     {
 430                       fndecl = ao;
 431                       break;
 432                     }
 433                   else if (TREE_CODE (ao) != BLOCK)
 434                     break;
 435
 436                   block = BLOCK_SUPERCONTEXT (block);
 437                 }
 438               if (fndecl)
 439                 abstract_origin = block;
 440               else
 441                 {
 442                   while (block && TREE_CODE (block) == BLOCK)
 443                     block = BLOCK_SUPERCONTEXT (block);
 444
 445                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 446                     fndecl = block;
 447                   abstract_origin = NULL;
 448                 }
 449               if (fndecl)
 450                 {
 451                   expanded_location s = expand_location (*locus);
 452                   pp_comma (context->printer);
 453                   pp_newline (context->printer);
 454                   if (s.file != NULL)
 455                     {
 456                       if (context->show_column)
 457                         pp_printf (context->printer,
 458                                    _("    inlined from %qs at %r%s:%d:%d%R"),
 459                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 460                                    "locus", s.file, s.line, s.column);
 461                       else
 462                         pp_printf (context->printer,
 463                                    _("    inlined from %qs at %r%s:%d%R"),
 464                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 465                                    "locus", s.file, s.line);
 466
 467                     }
 468                   else
 469                     pp_printf (context->printer, _("    inlined from %qs"),
 470                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 471                 }
 472             }
 473           pp_colon (context->printer);
 474         }
 475
 476       diagnostic_set_last_function (context, diagnostic);
 477       pp_newline_and_flush (context->printer);
 478       context->printer->prefix = old_prefix;
 479       free ((char*) new_prefix);
 480     }
 481 }
 482
 483 tree
 484 lhd_make_node (enum tree_code code)
 485 {
 486   return make_node (code);
 487 }
 488
 489 HOST_WIDE_INT
 490 lhd_to_target_charset (HOST_WIDE_INT c)
 491 {
 492   return c;
 493 }
 494
 495 tree
 496 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 497 {
 498   return expr;
 499 }
 500
 501 /* Return sharing kind if OpenMP sharing attribute of DECL is
 502    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 503
 504 enum omp_clause_default_kind
 505 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 506 {
 507   if (DECL_ARTIFICIAL (decl))
 508     return OMP_CLAUSE_DEFAULT_SHARED;
 509   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 510 }
 511
 512 /* Generate code to copy SRC to DST.  */
 513
 514 tree
 515 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 516 {
 517   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 518 }
 519
 520 /* Register language specific type size variables as potentially OpenMP
 521    firstprivate variables.  */
 522
 523 void
 524 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 525                                    tree t ATTRIBUTE_UNUSED)
 526 {
 527 }
 528
 529 /* Return true if TYPE is an OpenMP mappable type.  By default return true
 530    if type is complete.  */
 531
 532 bool
 533 lhd_omp_mappable_type (tree type)
 534 {
 535   return COMPLETE_TYPE_P (type);
 536 }
 537
 538 /* Common function for add_builtin_function and
 539    add_builtin_function_ext_scope.  */
 540 static tree
 541 add_builtin_function_common (const char *name,
 542                              tree type,
 543                              int function_code,
 544                              enum built_in_class cl,
 545                              const char *library_name,
 546                              tree attrs,
 547                              tree (*hook) (tree))
 548 {
 549   tree   id = get_identifier (name);
 550   tree decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, id, type);
 551
 552   TREE_PUBLIC (decl)         = 1;
 553   DECL_EXTERNAL (decl)       = 1;
 554   DECL_BUILT_IN_CLASS (decl) = cl;
 555
 556   DECL_FUNCTION_CODE (decl)  = (enum built_in_function) function_code;
 557
 558   /* DECL_FUNCTION_CODE is a bitfield; verify that the value fits.  */
 559   gcc_assert (DECL_FUNCTION_CODE (decl) == function_code);
 560
 561   if (library_name)
 562     {
 563       tree libname = get_identifier (library_name);
 564       SET_DECL_ASSEMBLER_NAME (decl, libname);
 565     }
 566
 567   /* Possibly apply some default attributes to this built-in function.  */
 568   if (attrs)
 569     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 570   else
 571     decl_attributes (&decl, NULL_TREE, 0);
 572
 573   return hook (decl);
 574
 575 }
 576
 577 /* Create a builtin function.  */
 578
 579 tree
 580 add_builtin_function (const char *name,
 581                       tree type,
 582                       int function_code,
 583                       enum built_in_class cl,
 584                       const char *library_name,
 585                       tree attrs)
 586 {
 587   return add_builtin_function_common (name, type, function_code, cl,
 588                                       library_name, attrs,
 589                                       lang_hooks.builtin_function);
 590 }
 591
 592 /* Like add_builtin_function, but make sure the scope is the external scope.
 593    This is used to delay putting in back end builtin functions until the ISA
 594    that defines the builtin is declared via function specific target options,
 595    which can save memory for machines like the x86_64 that have multiple ISAs.
 596    If this points to the same function as builtin_function, the backend must
 597    add all of the builtins at program initialization time.  */
 598
 599 tree
 600 add_builtin_function_ext_scope (const char *name,
 601                                 tree type,
 602                                 int function_code,
 603                                 enum built_in_class cl,
 604                                 const char *library_name,
 605                                 tree attrs)
 606 {
 607   return add_builtin_function_common (name, type, function_code, cl,
 608                                       library_name, attrs,
 609                                       lang_hooks.builtin_function_ext_scope);
 610 }
 611
 612 tree
 613 lhd_builtin_function (tree decl)
 614 {
 615   lang_hooks.decls.pushdecl (decl);
 616   return decl;
 617 }
 618
 619 /* Create a builtin type.  */
 620
 621 tree
 622 add_builtin_type (const char *name, tree type)
 623 {
 624   tree   id = get_identifier (name);
 625   tree decl = build_decl (BUILTINS_LOCATION, TYPE_DECL, id, type);
 626   return lang_hooks.decls.pushdecl (decl);
 627 }
 628
 629 /* LTO hooks.  */
 630
 631 /* Used to save and restore any previously active section.  */
 632 static section *saved_section;
 633
 634
 635 /* Begin a new LTO output section named NAME.  This default implementation
 636    saves the old section and emits assembly code to switch to the new
 637    section.  */
 638
 639 void
 640 lhd_begin_section (const char *name)
 641 {
 642   section *section;
 643
 644   /* Save the old section so we can restore it in lto_end_asm_section.  */
 645   gcc_assert (!saved_section);
 646   saved_section = in_section;
 647   if (!saved_section)
 648     saved_section = text_section;
 649
 650   /* Create a new section and switch to it.  */
 651   section = get_section (name, SECTION_DEBUG, NULL);
 652   switch_to_section (section);
 653 }
 654
 655
 656 /* Write DATA of length LEN to the current LTO output section.  This default
 657    implementation just calls assemble_string and frees BLOCK.  */
 658
 659 void
 660 lhd_append_data (const void *data, size_t len, void *block)
 661 {
 662   if (data)
 663     assemble_string ((const char *)data, len);
 664   free (block);
 665 }
 666
 667
 668 /* Finish the current LTO output section.  This default implementation emits
 669    assembly code to switch to any section previously saved by
 670    lhd_begin_section.  */
 671
 672 void
 673 lhd_end_section (void)
 674 {
 675   if (saved_section)
 676     {
 677       switch_to_section (saved_section);
 678       saved_section = NULL;
 679     }
 680 }
 681
 682 /* Empty function that is replaced with appropriate language dependent
 683    frame cleanup function for _Cilk_spawn.  */
 684
 685 void
 686 lhd_install_body_with_frame_cleanup (tree, tree)
 687 {
 688 }
 689
 690 /* Empty function to handle cilk_valid_spawn.  */
 691 bool
 692 lhd_cilk_detect_spawn (tree *)
 693 {
 694   return false;
 695 }