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_FILE_SCOPE_P (decl))
 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 (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                    const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 360 {
 361   return false;
 362 }
 363
 364 /* The default function to print out name of current function that caused
 365    an error.  */
 366 void
 367 lhd_print_error_function (diagnostic_context *context, const char *file,
 368                           diagnostic_info *diagnostic)
 369 {
 370   if (diagnostic_last_function_changed (context, diagnostic))
 371     {
 372       const char *old_prefix = context->printer->prefix;
 373       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 374       char *new_prefix = (file && abstract_origin == NULL)
 375                          ? file_name_as_prefix (file) : NULL;
 376
 377       pp_set_prefix (context->printer, new_prefix);
 378
 379       if (current_function_decl == NULL)
 380         pp_printf (context->printer, _("At top level:"));
 381       else
 382         {
 383           tree fndecl, ao;
 384
 385           if (abstract_origin)
 386             {
 387               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 388               while (TREE_CODE (ao) == BLOCK
 389                      && BLOCK_ABSTRACT_ORIGIN (ao)
 390                      && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 391                 ao = BLOCK_ABSTRACT_ORIGIN (ao);
 392               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 393               fndecl = ao;
 394             }
 395           else
 396             fndecl = current_function_decl;
 397
 398           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 399             pp_printf
 400               (context->printer, _("In member function %qs"),
 401                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 402           else
 403             pp_printf
 404               (context->printer, _("In function %qs"),
 405                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 406
 407           while (abstract_origin)
 408             {
 409               location_t *locus;
 410               tree block = abstract_origin;
 411
 412               locus = &BLOCK_SOURCE_LOCATION (block);
 413               fndecl = NULL;
 414               block = BLOCK_SUPERCONTEXT (block);
 415               while (block && TREE_CODE (block) == BLOCK
 416                      && BLOCK_ABSTRACT_ORIGIN (block))
 417                 {
 418                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 419
 420                   while (TREE_CODE (ao) == BLOCK
 421                          && BLOCK_ABSTRACT_ORIGIN (ao)
 422                          && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 423                     ao = BLOCK_ABSTRACT_ORIGIN (ao);
 424
 425                   if (TREE_CODE (ao) == FUNCTION_DECL)
 426                     {
 427                       fndecl = ao;
 428                       break;
 429                     }
 430                   else if (TREE_CODE (ao) != BLOCK)
 431                     break;
 432
 433                   block = BLOCK_SUPERCONTEXT (block);
 434                 }
 435               if (fndecl)
 436                 abstract_origin = block;
 437               else
 438                 {
 439                   while (block && TREE_CODE (block) == BLOCK)
 440                     block = BLOCK_SUPERCONTEXT (block);
 441
 442                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 443                     fndecl = block;
 444                   abstract_origin = NULL;
 445                 }
 446               if (fndecl)
 447                 {
 448                   expanded_location s = expand_location (*locus);
 449                   pp_character (context->printer, ',');
 450                   pp_newline (context->printer);
 451                   if (s.file != NULL)
 452                     {
 453                       if (context->show_column)
 454                         pp_printf (context->printer,
 455                                    _("    inlined from %qs at %s:%d:%d"),
 456                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 457                                    s.file, s.line, s.column);
 458                       else
 459                         pp_printf (context->printer,
 460                                    _("    inlined from %qs at %s:%d"),
 461                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 462                                    s.file, s.line);
 463
 464                     }
 465                   else
 466                     pp_printf (context->printer, _("    inlined from %qs"),
 467                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 468                 }
 469             }
 470           pp_character (context->printer, ':');
 471         }
 472
 473       diagnostic_set_last_function (context, diagnostic);
 474       pp_flush (context->printer);
 475       context->printer->prefix = old_prefix;
 476       free ((char*) new_prefix);
 477     }
 478 }
 479
 480 tree
 481 lhd_callgraph_analyze_expr (tree *tp ATTRIBUTE_UNUSED,
 482                             int *walk_subtrees ATTRIBUTE_UNUSED)
 483 {
 484   return NULL;
 485 }
 486
 487 tree
 488 lhd_make_node (enum tree_code code)
 489 {
 490   return make_node (code);
 491 }
 492
 493 HOST_WIDE_INT
 494 lhd_to_target_charset (HOST_WIDE_INT c)
 495 {
 496   return c;
 497 }
 498
 499 tree
 500 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 501 {
 502   return expr;
 503 }
 504
 505 /* Return sharing kind if OpenMP sharing attribute of DECL is
 506    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 507
 508 enum omp_clause_default_kind
 509 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 510 {
 511   if (DECL_ARTIFICIAL (decl))
 512     return OMP_CLAUSE_DEFAULT_SHARED;
 513   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 514 }
 515
 516 /* Generate code to copy SRC to DST.  */
 517
 518 tree
 519 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 520 {
 521   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 522 }
 523
 524 /* Register language specific type size variables as potentially OpenMP
 525    firstprivate variables.  */
 526
 527 void
 528 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 529                                    tree t ATTRIBUTE_UNUSED)
 530 {
 531 }
 532
 533 /* Common function for add_builtin_function and
 534    add_builtin_function_ext_scope.  */
 535 static tree
 536 add_builtin_function_common (const char *name,
 537                              tree type,
 538                              int function_code,
 539                              enum built_in_class cl,
 540                              const char *library_name,
 541                              tree attrs,
 542                              tree (*hook) (tree))
 543 {
 544   tree   id = get_identifier (name);
 545   tree decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, id, type);
 546
 547   TREE_PUBLIC (decl)         = 1;
 548   DECL_EXTERNAL (decl)       = 1;
 549   DECL_BUILT_IN_CLASS (decl) = cl;
 550
 551   DECL_FUNCTION_CODE (decl)  = (enum built_in_function) function_code;
 552
 553   /* DECL_FUNCTION_CODE is a bitfield; verify that the value fits.  */
 554   gcc_assert (DECL_FUNCTION_CODE (decl) == function_code);
 555
 556   if (library_name)
 557     {
 558       tree libname = get_identifier (library_name);
 559       SET_DECL_ASSEMBLER_NAME (decl, libname);
 560     }
 561
 562   /* Possibly apply some default attributes to this built-in function.  */
 563   if (attrs)
 564     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 565   else
 566     decl_attributes (&decl, NULL_TREE, 0);
 567
 568   return hook (decl);
 569
 570 }
 571
 572 /* Create a builtin function.  */
 573
 574 tree
 575 add_builtin_function (const char *name,
 576                       tree type,
 577                       int function_code,
 578                       enum built_in_class cl,
 579                       const char *library_name,
 580                       tree attrs)
 581 {
 582   return add_builtin_function_common (name, type, function_code, cl,
 583                                       library_name, attrs,
 584                                       lang_hooks.builtin_function);
 585 }
 586
 587 /* Like add_builtin_function, but make sure the scope is the external scope.
 588    This is used to delay putting in back end builtin functions until the ISA
 589    that defines the builtin is declared via function specific target options,
 590    which can save memory for machines like the x86_64 that have multiple ISAs.
 591    If this points to the same function as builtin_function, the backend must
 592    add all of the builtins at program initialization time.  */
 593
 594 tree
 595 add_builtin_function_ext_scope (const char *name,
 596                                 tree type,
 597                                 int function_code,
 598                                 enum built_in_class cl,
 599                                 const char *library_name,
 600                                 tree attrs)
 601 {
 602   return add_builtin_function_common (name, type, function_code, cl,
 603                                       library_name, attrs,
 604                                       lang_hooks.builtin_function_ext_scope);
 605 }
 606
 607 tree
 608 lhd_builtin_function (tree decl)
 609 {
 610   lang_hooks.decls.pushdecl (decl);
 611   return decl;
 612 }
 613
 614 /* LTO hooks.  */
 615
 616 /* Used to save and restore any previously active section.  */
 617 static section *saved_section;
 618
 619
 620 /* Begin a new LTO output section named NAME.  This default implementation
 621    saves the old section and emits assembly code to switch to the new
 622    section.  */
 623
 624 void
 625 lhd_begin_section (const char *name)
 626 {
 627   section *section;
 628
 629   /* Save the old section so we can restore it in lto_end_asm_section.  */
 630   gcc_assert (!saved_section);
 631   saved_section = in_section;
 632   if (!saved_section)
 633     saved_section = text_section;
 634
 635   /* Create a new section and switch to it.  */
 636   section = get_section (name, SECTION_DEBUG, NULL);
 637   switch_to_section (section);
 638 }
 639
 640
 641 /* Write DATA of length LEN to the current LTO output section.  This default
 642    implementation just calls assemble_string and frees BLOCK.  */
 643
 644 void
 645 lhd_append_data (const void *data, size_t len, void *block)
 646 {
 647   if (data)
 648     assemble_string ((const char *)data, len);
 649   free (block);
 650 }
 651
 652
 653 /* Finish the current LTO output section.  This default implementation emits
 654    assembly code to switch to any section previously saved by
 655    lhd_begin_section.  */
 656
 657 void
 658 lhd_end_section (void)
 659 {
 660   if (saved_section)
 661     {
 662       switch_to_section (saved_section);
 663       saved_section = NULL;
 664     }
 665 }