gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4    Contributed by Alexandre Oliva  <aoliva@redhat.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "intl.h"
  26 #include "tm.h"
  27 #include "toplev.h"
  28 #include "tree.h"
  29 #include "tree-inline.h"
  30 #include "gimple.h"
  31 #include "rtl.h"
  32 #include "insn-config.h"
  33 #include "integrate.h"
  34 #include "flags.h"
  35 #include "langhooks.h"
  36 #include "target.h"
  37 #include "langhooks-def.h"
  38 #include "ggc.h"
  39 #include "diagnostic.h"
  40 #include "tree-diagnostic.h"
  41 #include "cgraph.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).  */
  66
  67 void
  68 lhd_do_nothing_i (int ARG_UNUSED (i))
  69 {
  70 }
  71
  72 /* Do nothing (int, int, int).  Return NULL_TREE.  */
  73
  74 tree
  75 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  76                                      int ARG_UNUSED (j),
  77                                      int ARG_UNUSED (k))
  78 {
  79   return NULL_TREE;
  80 }
  81
  82 /* Do nothing (function).  */
  83
  84 void
  85 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  86 {
  87 }
  88
  89 /* Do nothing (return NULL_TREE).  */
  90
  91 tree
  92 lhd_return_null_tree_v (void)
  93 {
  94   return NULL_TREE;
  95 }
  96
  97 /* Do nothing (return NULL_TREE).  */
  98
  99 tree
 100 lhd_return_null_tree (tree ARG_UNUSED (t))
 101 {
 102   return NULL_TREE;
 103 }
 104
 105 /* Do nothing (return NULL_TREE).  */
 106
 107 tree
 108 lhd_return_null_const_tree (const_tree ARG_UNUSED (t))
 109 {
 110   return NULL_TREE;
 111 }
 112
 113 /* The default post options hook.  */
 114
 115 bool
 116 lhd_post_options (const char ** ARG_UNUSED (pfilename))
 117 {
 118   /* Excess precision other than "fast" requires front-end
 119      support.  */
 120   flag_excess_precision_cmdline = EXCESS_PRECISION_FAST;
 121   return false;
 122 }
 123
 124 /* Called from by print-tree.c.  */
 125
 126 void
 127 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 128                         tree ARG_UNUSED (node),
 129                         int ARG_UNUSED (indent))
 130 {
 131 }
 132
 133 /* Called from check_global_declarations.  */
 134
 135 bool
 136 lhd_warn_unused_global_decl (const_tree decl)
 137 {
 138   /* This is what used to exist in check_global_declarations.  Probably
 139      not many of these actually apply to non-C languages.  */
 140
 141   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 142     return false;
 143   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 144     return false;
 145   if (DECL_IN_SYSTEM_HEADER (decl))
 146     return false;
 147
 148   return true;
 149 }
 150
 151 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 152 void
 153 lhd_set_decl_assembler_name (tree decl)
 154 {
 155   tree id;
 156
 157   /* The language-independent code should never use the
 158      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 159      VAR_DECLs for variables with static storage duration need a real
 160      DECL_ASSEMBLER_NAME.  */
 161   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 162               || (TREE_CODE (decl) == VAR_DECL
 163                   && (TREE_STATIC (decl)
 164                       || DECL_EXTERNAL (decl)
 165                       || TREE_PUBLIC (decl))));
 166
 167   /* By default, assume the name to use in assembly code is the same
 168      as that used in the source language.  (That's correct for C, and
 169      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 170      DECL_NAME in build_decl, so this choice provides backwards
 171      compatibility with existing front-ends.  This assumption is wrapped
 172      in a target hook, to allow for target-specific modification of the
 173      identifier.
 174
 175      Can't use just the variable's own name for a variable whose scope
 176      is less than the whole compilation.  Concatenate a distinguishing
 177      number - we use the DECL_UID.  */
 178
 179   if (TREE_PUBLIC (decl) || DECL_CONTEXT (decl) == NULL_TREE)
 180     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 181   else
 182     {
 183       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 184       char *label;
 185
 186       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 187       id = get_identifier (label);
 188     }
 189   SET_DECL_ASSEMBLER_NAME (decl, id);
 190
 191 }
 192
 193 /* Type promotion for variable arguments.  */
 194 tree
 195 lhd_type_promotes_to (tree ARG_UNUSED (type))
 196 {
 197   gcc_unreachable ();
 198 }
 199
 200 /* Registration of machine- or os-specific builtin types.  */
 201 void
 202 lhd_register_builtin_type (tree ARG_UNUSED (type),
 203                            const char * ARG_UNUSED (name))
 204 {
 205 }
 206
 207 /* Invalid use of an incomplete type.  */
 208 void
 209 lhd_incomplete_type_error (const_tree ARG_UNUSED (value), const_tree type)
 210 {
 211   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 212   return;
 213 }
 214
 215 /* Provide a default routine for alias sets that always returns -1.  This
 216    is used by languages that don't need to do anything special.  */
 217
 218 alias_set_type
 219 lhd_get_alias_set (tree ARG_UNUSED (t))
 220 {
 221   return -1;
 222 }
 223
 224 /* This is the default decl_printable_name function.  */
 225
 226 const char *
 227 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 228 {
 229   gcc_assert (decl && DECL_NAME (decl));
 230   return IDENTIFIER_POINTER (DECL_NAME (decl));
 231 }
 232
 233 /* This is the default dwarf_name function.  */
 234
 235 const char *
 236 lhd_dwarf_name (tree t, int verbosity)
 237 {
 238   gcc_assert (DECL_P (t));
 239
 240   return lang_hooks.decl_printable_name (t, verbosity);
 241 }
 242
 243 /* This compares two types for equivalence ("compatible" in C-based languages).
 244    This routine should only return 1 if it is sure.  It should not be used
 245    in contexts where erroneously returning 0 causes problems.  */
 246
 247 int
 248 lhd_types_compatible_p (tree x, tree y)
 249 {
 250   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 251 }
 252
 253 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 254    nodes.  Returns nonzero if it does not want the usual dumping of the
 255    second argument.  */
 256
 257 bool
 258 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 259 {
 260   return false;
 261 }
 262
 263 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 264    language-specific way.  */
 265
 266 int
 267 lhd_tree_dump_type_quals (const_tree t)
 268 {
 269   return TYPE_QUALS (t);
 270 }
 271
 272 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 273
 274 int
 275 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED,
 276                    gimple_seq *pre_p ATTRIBUTE_UNUSED,
 277                    gimple_seq *post_p ATTRIBUTE_UNUSED)
 278 {
 279   return GS_UNHANDLED;
 280 }
 281
 282 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 283    which is a language-specific tree code in category tcc_constant or
 284    tcc_exceptional.  The default expects never to be called.  */
 285 size_t
 286 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 287 {
 288   gcc_unreachable ();
 289 }
 290
 291 /* Return true if decl, which is a function decl, may be called by a
 292    sibcall.  */
 293
 294 bool
 295 lhd_decl_ok_for_sibcall (const_tree decl ATTRIBUTE_UNUSED)
 296 {
 297   return true;
 298 }
 299
 300 /* lang_hooks.decls.final_write_globals: perform final processing on
 301    global variables.  */
 302 void
 303 write_global_declarations (void)
 304 {
 305   tree globals, decl, *vec;
 306   int len, i;
 307
 308   /* This lang hook is dual-purposed, and also finalizes the
 309      compilation unit.  */
 310   cgraph_finalize_compilation_unit ();
 311
 312   /* Really define vars that have had only a tentative definition.
 313      Really output inline functions that must actually be callable
 314      and have not been output so far.  */
 315
 316   globals = lang_hooks.decls.getdecls ();
 317   len = list_length (globals);
 318   vec = XNEWVEC (tree, len);
 319
 320   /* Process the decls in reverse order--earliest first.
 321      Put them into VEC from back to front, then take out from front.  */
 322
 323   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
 324     vec[len - i - 1] = decl;
 325
 326   wrapup_global_declarations (vec, len);
 327   check_global_declarations (vec, len);
 328   emit_debug_global_declarations (vec, len);
 329
 330   /* Clean up.  */
 331   free (vec);
 332 }
 333
 334 /* Called to perform language-specific initialization of CTX.  */
 335 void
 336 lhd_initialize_diagnostics (struct diagnostic_context *ctx ATTRIBUTE_UNUSED)
 337 {
 338 }
 339
 340 /* The default function to print out name of current function that caused
 341    an error.  */
 342 void
 343 lhd_print_error_function (diagnostic_context *context, const char *file,
 344                           diagnostic_info *diagnostic)
 345 {
 346   if (diagnostic_last_function_changed (context, diagnostic))
 347     {
 348       const char *old_prefix = context->printer->prefix;
 349       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 350       char *new_prefix = (file && abstract_origin == NULL)
 351                          ? file_name_as_prefix (file) : NULL;
 352
 353       pp_set_prefix (context->printer, new_prefix);
 354
 355       if (current_function_decl == NULL)
 356         pp_printf (context->printer, _("At top level:"));
 357       else
 358         {
 359           tree fndecl, ao;
 360
 361           if (abstract_origin)
 362             {
 363               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 364               while (TREE_CODE (ao) == BLOCK
 365                      && BLOCK_ABSTRACT_ORIGIN (ao)
 366                      && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 367                 ao = BLOCK_ABSTRACT_ORIGIN (ao);
 368               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 369               fndecl = ao;
 370             }
 371           else
 372             fndecl = current_function_decl;
 373
 374           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 375             pp_printf
 376               (context->printer, _("In member function %qs"),
 377                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 378           else
 379             pp_printf
 380               (context->printer, _("In function %qs"),
 381                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 382
 383           while (abstract_origin)
 384             {
 385               location_t *locus;
 386               tree block = abstract_origin;
 387
 388               locus = &BLOCK_SOURCE_LOCATION (block);
 389               fndecl = NULL;
 390               block = BLOCK_SUPERCONTEXT (block);
 391               while (block && TREE_CODE (block) == BLOCK
 392                      && BLOCK_ABSTRACT_ORIGIN (block))
 393                 {
 394                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 395
 396                   while (TREE_CODE (ao) == BLOCK
 397                          && BLOCK_ABSTRACT_ORIGIN (ao)
 398                          && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 399                     ao = BLOCK_ABSTRACT_ORIGIN (ao);
 400
 401                   if (TREE_CODE (ao) == FUNCTION_DECL)
 402                     {
 403                       fndecl = ao;
 404                       break;
 405                     }
 406                   else if (TREE_CODE (ao) != BLOCK)
 407                     break;
 408
 409                   block = BLOCK_SUPERCONTEXT (block);
 410                 }
 411               if (fndecl)
 412                 abstract_origin = block;
 413               else
 414                 {
 415                   while (block && TREE_CODE (block) == BLOCK)
 416                     block = BLOCK_SUPERCONTEXT (block);
 417
 418                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 419                     fndecl = block;
 420                   abstract_origin = NULL;
 421                 }
 422               if (fndecl)
 423                 {
 424                   expanded_location s = expand_location (*locus);
 425                   pp_character (context->printer, ',');
 426                   pp_newline (context->printer);
 427                   if (s.file != NULL)
 428                     {
 429                       if (context->show_column)
 430                         pp_printf (context->printer,
 431                                    _("    inlined from %qs at %s:%d:%d"),
 432                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 433                                    s.file, s.line, s.column);
 434                       else
 435                         pp_printf (context->printer,
 436                                    _("    inlined from %qs at %s:%d"),
 437                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 438                                    s.file, s.line);
 439
 440                     }
 441                   else
 442                     pp_printf (context->printer, _("    inlined from %qs"),
 443                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 444                 }
 445             }
 446           pp_character (context->printer, ':');
 447         }
 448
 449       diagnostic_set_last_function (context, diagnostic);
 450       pp_flush (context->printer);
 451       context->printer->prefix = old_prefix;
 452       free ((char*) new_prefix);
 453     }
 454 }
 455
 456 tree
 457 lhd_callgraph_analyze_expr (tree *tp ATTRIBUTE_UNUSED,
 458                             int *walk_subtrees ATTRIBUTE_UNUSED)
 459 {
 460   return NULL;
 461 }
 462
 463 tree
 464 lhd_make_node (enum tree_code code)
 465 {
 466   return make_node (code);
 467 }
 468
 469 HOST_WIDE_INT
 470 lhd_to_target_charset (HOST_WIDE_INT c)
 471 {
 472   return c;
 473 }
 474
 475 tree
 476 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 477 {
 478   return expr;
 479 }
 480
 481 /* Return sharing kind if OpenMP sharing attribute of DECL is
 482    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 483
 484 enum omp_clause_default_kind
 485 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 486 {
 487   if (DECL_ARTIFICIAL (decl))
 488     return OMP_CLAUSE_DEFAULT_SHARED;
 489   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 490 }
 491
 492 /* Generate code to copy SRC to DST.  */
 493
 494 tree
 495 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 496 {
 497   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 498 }
 499
 500 /* Register language specific type size variables as potentially OpenMP
 501    firstprivate variables.  */
 502
 503 void
 504 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 505                                    tree t ATTRIBUTE_UNUSED)
 506 {
 507 }
 508
 509 /* Common function for add_builtin_function and
 510    add_builtin_function_ext_scope.  */
 511 static tree
 512 add_builtin_function_common (const char *name,
 513                              tree type,
 514                              int function_code,
 515                              enum built_in_class cl,
 516                              const char *library_name,
 517                              tree attrs,
 518                              tree (*hook) (tree))
 519 {
 520   tree   id = get_identifier (name);
 521   tree decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, id, type);
 522
 523   TREE_PUBLIC (decl)         = 1;
 524   DECL_EXTERNAL (decl)       = 1;
 525   DECL_BUILT_IN_CLASS (decl) = cl;
 526
 527   DECL_FUNCTION_CODE (decl)  = (enum built_in_function) function_code;
 528
 529   /* DECL_FUNCTION_CODE is a bitfield; verify that the value fits.  */
 530   gcc_assert (DECL_FUNCTION_CODE (decl) == function_code);
 531
 532   if (library_name)
 533     {
 534       tree libname = get_identifier (library_name);
 535       SET_DECL_ASSEMBLER_NAME (decl, libname);
 536     }
 537
 538   /* Possibly apply some default attributes to this built-in function.  */
 539   if (attrs)
 540     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 541   else
 542     decl_attributes (&decl, NULL_TREE, 0);
 543
 544   return hook (decl);
 545
 546 }
 547
 548 /* Create a builtin function.  */
 549
 550 tree
 551 add_builtin_function (const char *name,
 552                       tree type,
 553                       int function_code,
 554                       enum built_in_class cl,
 555                       const char *library_name,
 556                       tree attrs)
 557 {
 558   return add_builtin_function_common (name, type, function_code, cl,
 559                                       library_name, attrs,
 560                                       lang_hooks.builtin_function);
 561 }
 562
 563 /* Like add_builtin_function, but make sure the scope is the external scope.
 564    This is used to delay putting in back end builtin functions until the ISA
 565    that defines the builtin is declared via function specific target options,
 566    which can save memory for machines like the x86_64 that have multiple ISAs.
 567    If this points to the same function as builtin_function, the backend must
 568    add all of the builtins at program initialization time.  */
 569
 570 tree
 571 add_builtin_function_ext_scope (const char *name,
 572                                 tree type,
 573                                 int function_code,
 574                                 enum built_in_class cl,
 575                                 const char *library_name,
 576                                 tree attrs)
 577 {
 578   return add_builtin_function_common (name, type, function_code, cl,
 579                                       library_name, attrs,
 580                                       lang_hooks.builtin_function_ext_scope);
 581 }
 582
 583 tree
 584 lhd_builtin_function (tree decl)
 585 {
 586   lang_hooks.decls.pushdecl (decl);
 587   return decl;
 588 }
 589
 590 /* LTO hooks.  */
 591
 592 /* Used to save and restore any previously active section.  */
 593 static section *saved_section;
 594
 595
 596 /* Begin a new LTO output section named NAME.  This default implementation
 597    saves the old section and emits assembly code to switch to the new
 598    section.  */
 599
 600 void
 601 lhd_begin_section (const char *name)
 602 {
 603   section *section;
 604
 605   /* Save the old section so we can restore it in lto_end_asm_section.  */
 606   gcc_assert (!saved_section);
 607   saved_section = in_section;
 608   if (!saved_section)
 609     saved_section = text_section;
 610
 611   /* Create a new section and switch to it.  */
 612   section = get_section (name, SECTION_DEBUG, NULL);
 613   switch_to_section (section);
 614 }
 615
 616
 617 /* Write DATA of length LEN to the current LTO output section.  This default
 618    implementation just calls assemble_string and frees BLOCK.  */
 619
 620 void
 621 lhd_append_data (const void *data, size_t len, void *block)
 622 {
 623   if (data)
 624     assemble_string ((const char *)data, len);
 625   free (block);
 626 }
 627
 628
 629 /* Finish the current LTO output section.  This default implementation emits
 630    assembly code to switch to any section previously saved by
 631    lhd_begin_section.  */
 632
 633 void
 634 lhd_end_section (void)
 635 {
 636   if (saved_section)
 637     {
 638       switch_to_section (saved_section);
 639       saved_section = NULL;
 640     }
 641 }