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 = DECL_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 /* 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 /* The default function to print out name of current function that caused
 355    an error.  */
 356 void
 357 lhd_print_error_function (diagnostic_context *context, const char *file,
 358                           diagnostic_info *diagnostic)
 359 {
 360   if (diagnostic_last_function_changed (context, diagnostic))
 361     {
 362       const char *old_prefix = context->printer->prefix;
 363       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 364       char *new_prefix = (file && abstract_origin == NULL)
 365                          ? file_name_as_prefix (file) : NULL;
 366
 367       pp_set_prefix (context->printer, new_prefix);
 368
 369       if (current_function_decl == NULL)
 370         pp_printf (context->printer, _("At top level:"));
 371       else
 372         {
 373           tree fndecl, ao;
 374
 375           if (abstract_origin)
 376             {
 377               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 378               while (TREE_CODE (ao) == BLOCK
 379                      && BLOCK_ABSTRACT_ORIGIN (ao)
 380                      && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 381                 ao = BLOCK_ABSTRACT_ORIGIN (ao);
 382               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 383               fndecl = ao;
 384             }
 385           else
 386             fndecl = current_function_decl;
 387
 388           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 389             pp_printf
 390               (context->printer, _("In member function %qs"),
 391                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 392           else
 393             pp_printf
 394               (context->printer, _("In function %qs"),
 395                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 396
 397           while (abstract_origin)
 398             {
 399               location_t *locus;
 400               tree block = abstract_origin;
 401
 402               locus = &BLOCK_SOURCE_LOCATION (block);
 403               fndecl = NULL;
 404               block = BLOCK_SUPERCONTEXT (block);
 405               while (block && TREE_CODE (block) == BLOCK
 406                      && BLOCK_ABSTRACT_ORIGIN (block))
 407                 {
 408                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 409
 410                   while (TREE_CODE (ao) == BLOCK
 411                          && BLOCK_ABSTRACT_ORIGIN (ao)
 412                          && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 413                     ao = BLOCK_ABSTRACT_ORIGIN (ao);
 414
 415                   if (TREE_CODE (ao) == FUNCTION_DECL)
 416                     {
 417                       fndecl = ao;
 418                       break;
 419                     }
 420                   else if (TREE_CODE (ao) != BLOCK)
 421                     break;
 422
 423                   block = BLOCK_SUPERCONTEXT (block);
 424                 }
 425               if (fndecl)
 426                 abstract_origin = block;
 427               else
 428                 {
 429                   while (block && TREE_CODE (block) == BLOCK)
 430                     block = BLOCK_SUPERCONTEXT (block);
 431
 432                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 433                     fndecl = block;
 434                   abstract_origin = NULL;
 435                 }
 436               if (fndecl)
 437                 {
 438                   expanded_location s = expand_location (*locus);
 439                   pp_character (context->printer, ',');
 440                   pp_newline (context->printer);
 441                   if (s.file != NULL)
 442                     {
 443                       if (context->show_column)
 444                         pp_printf (context->printer,
 445                                    _("    inlined from %qs at %s:%d:%d"),
 446                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 447                                    s.file, s.line, s.column);
 448                       else
 449                         pp_printf (context->printer,
 450                                    _("    inlined from %qs at %s:%d"),
 451                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 452                                    s.file, s.line);
 453
 454                     }
 455                   else
 456                     pp_printf (context->printer, _("    inlined from %qs"),
 457                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 458                 }
 459             }
 460           pp_character (context->printer, ':');
 461         }
 462
 463       diagnostic_set_last_function (context, diagnostic);
 464       pp_flush (context->printer);
 465       context->printer->prefix = old_prefix;
 466       free ((char*) new_prefix);
 467     }
 468 }
 469
 470 tree
 471 lhd_callgraph_analyze_expr (tree *tp ATTRIBUTE_UNUSED,
 472                             int *walk_subtrees ATTRIBUTE_UNUSED)
 473 {
 474   return NULL;
 475 }
 476
 477 tree
 478 lhd_make_node (enum tree_code code)
 479 {
 480   return make_node (code);
 481 }
 482
 483 HOST_WIDE_INT
 484 lhd_to_target_charset (HOST_WIDE_INT c)
 485 {
 486   return c;
 487 }
 488
 489 tree
 490 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 491 {
 492   return expr;
 493 }
 494
 495 /* Return sharing kind if OpenMP sharing attribute of DECL is
 496    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 497
 498 enum omp_clause_default_kind
 499 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 500 {
 501   if (DECL_ARTIFICIAL (decl))
 502     return OMP_CLAUSE_DEFAULT_SHARED;
 503   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 504 }
 505
 506 /* Generate code to copy SRC to DST.  */
 507
 508 tree
 509 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 510 {
 511   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 512 }
 513
 514 /* Register language specific type size variables as potentially OpenMP
 515    firstprivate variables.  */
 516
 517 void
 518 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 519                                    tree t ATTRIBUTE_UNUSED)
 520 {
 521 }
 522
 523 /* Common function for add_builtin_function and
 524    add_builtin_function_ext_scope.  */
 525 static tree
 526 add_builtin_function_common (const char *name,
 527                              tree type,
 528                              int function_code,
 529                              enum built_in_class cl,
 530                              const char *library_name,
 531                              tree attrs,
 532                              tree (*hook) (tree))
 533 {
 534   tree   id = get_identifier (name);
 535   tree decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, id, type);
 536
 537   TREE_PUBLIC (decl)         = 1;
 538   DECL_EXTERNAL (decl)       = 1;
 539   DECL_BUILT_IN_CLASS (decl) = cl;
 540
 541   DECL_FUNCTION_CODE (decl)  = (enum built_in_function) function_code;
 542
 543   /* DECL_FUNCTION_CODE is a bitfield; verify that the value fits.  */
 544   gcc_assert (DECL_FUNCTION_CODE (decl) == function_code);
 545
 546   if (library_name)
 547     {
 548       tree libname = get_identifier (library_name);
 549       SET_DECL_ASSEMBLER_NAME (decl, libname);
 550     }
 551
 552   /* Possibly apply some default attributes to this built-in function.  */
 553   if (attrs)
 554     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 555   else
 556     decl_attributes (&decl, NULL_TREE, 0);
 557
 558   return hook (decl);
 559
 560 }
 561
 562 /* Create a builtin function.  */
 563
 564 tree
 565 add_builtin_function (const char *name,
 566                       tree type,
 567                       int function_code,
 568                       enum built_in_class cl,
 569                       const char *library_name,
 570                       tree attrs)
 571 {
 572   return add_builtin_function_common (name, type, function_code, cl,
 573                                       library_name, attrs,
 574                                       lang_hooks.builtin_function);
 575 }
 576
 577 /* Like add_builtin_function, but make sure the scope is the external scope.
 578    This is used to delay putting in back end builtin functions until the ISA
 579    that defines the builtin is declared via function specific target options,
 580    which can save memory for machines like the x86_64 that have multiple ISAs.
 581    If this points to the same function as builtin_function, the backend must
 582    add all of the builtins at program initialization time.  */
 583
 584 tree
 585 add_builtin_function_ext_scope (const char *name,
 586                                 tree type,
 587                                 int function_code,
 588                                 enum built_in_class cl,
 589                                 const char *library_name,
 590                                 tree attrs)
 591 {
 592   return add_builtin_function_common (name, type, function_code, cl,
 593                                       library_name, attrs,
 594                                       lang_hooks.builtin_function_ext_scope);
 595 }
 596
 597 tree
 598 lhd_builtin_function (tree decl)
 599 {
 600   lang_hooks.decls.pushdecl (decl);
 601   return decl;
 602 }
 603
 604 /* LTO hooks.  */
 605
 606 /* Used to save and restore any previously active section.  */
 607 static section *saved_section;
 608
 609
 610 /* Begin a new LTO output section named NAME.  This default implementation
 611    saves the old section and emits assembly code to switch to the new
 612    section.  */
 613
 614 void
 615 lhd_begin_section (const char *name)
 616 {
 617   section *section;
 618
 619   /* Save the old section so we can restore it in lto_end_asm_section.  */
 620   gcc_assert (!saved_section);
 621   saved_section = in_section;
 622   if (!saved_section)
 623     saved_section = text_section;
 624
 625   /* Create a new section and switch to it.  */
 626   section = get_section (name, SECTION_DEBUG, NULL);
 627   switch_to_section (section);
 628 }
 629
 630
 631 /* Write DATA of length LEN to the current LTO output section.  This default
 632    implementation just calls assemble_string and frees BLOCK.  */
 633
 634 void
 635 lhd_append_data (const void *data, size_t len, void *block)
 636 {
 637   if (data)
 638     assemble_string ((const char *)data, len);
 639   free (block);
 640 }
 641
 642
 643 /* Finish the current LTO output section.  This default implementation emits
 644    assembly code to switch to any section previously saved by
 645    lhd_begin_section.  */
 646
 647 void
 648 lhd_end_section (void)
 649 {
 650   if (saved_section)
 651     {
 652       switch_to_section (saved_section);
 653       saved_section = NULL;
 654     }
 655 }