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 of OPTS.  */
 341 void
 342 lhd_init_options_struct (struct gcc_options *opts ATTRIBUTE_UNUSED)
 343 {
 344 }
 345
 346 /* Called to perform language-specific options initialization.  */
 347 void
 348 lhd_init_options (unsigned int decoded_options_count ATTRIBUTE_UNUSED,
 349                   struct cl_decoded_option *decoded_options ATTRIBUTE_UNUSED)
 350 {
 351 }
 352
 353 /* By default, always complain about options for the wrong language.  */
 354 bool
 355 lhd_complain_wrong_lang_p (const struct cl_option *option ATTRIBUTE_UNUSED)
 356 {
 357   return true;
 358 }
 359
 360 /* By default, no language-specific options are valid.  */
 361 bool
 362 lhd_handle_option (size_t code ATTRIBUTE_UNUSED,
 363                    const char *arg ATTRIBUTE_UNUSED,
 364                    int value ATTRIBUTE_UNUSED, int kind ATTRIBUTE_UNUSED,
 365                    const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 366 {
 367   return false;
 368 }
 369
 370 /* The default function to print out name of current function that caused
 371    an error.  */
 372 void
 373 lhd_print_error_function (diagnostic_context *context, const char *file,
 374                           diagnostic_info *diagnostic)
 375 {
 376   if (diagnostic_last_function_changed (context, diagnostic))
 377     {
 378       const char *old_prefix = context->printer->prefix;
 379       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 380       char *new_prefix = (file && abstract_origin == NULL)
 381                          ? file_name_as_prefix (file) : NULL;
 382
 383       pp_set_prefix (context->printer, new_prefix);
 384
 385       if (current_function_decl == NULL)
 386         pp_printf (context->printer, _("At top level:"));
 387       else
 388         {
 389           tree fndecl, ao;
 390
 391           if (abstract_origin)
 392             {
 393               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 394               while (TREE_CODE (ao) == BLOCK
 395                      && BLOCK_ABSTRACT_ORIGIN (ao)
 396                      && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 397                 ao = BLOCK_ABSTRACT_ORIGIN (ao);
 398               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 399               fndecl = ao;
 400             }
 401           else
 402             fndecl = current_function_decl;
 403
 404           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 405             pp_printf
 406               (context->printer, _("In member function %qs"),
 407                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 408           else
 409             pp_printf
 410               (context->printer, _("In function %qs"),
 411                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 412
 413           while (abstract_origin)
 414             {
 415               location_t *locus;
 416               tree block = abstract_origin;
 417
 418               locus = &BLOCK_SOURCE_LOCATION (block);
 419               fndecl = NULL;
 420               block = BLOCK_SUPERCONTEXT (block);
 421               while (block && TREE_CODE (block) == BLOCK
 422                      && BLOCK_ABSTRACT_ORIGIN (block))
 423                 {
 424                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 425
 426                   while (TREE_CODE (ao) == BLOCK
 427                          && BLOCK_ABSTRACT_ORIGIN (ao)
 428                          && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 429                     ao = BLOCK_ABSTRACT_ORIGIN (ao);
 430
 431                   if (TREE_CODE (ao) == FUNCTION_DECL)
 432                     {
 433                       fndecl = ao;
 434                       break;
 435                     }
 436                   else if (TREE_CODE (ao) != BLOCK)
 437                     break;
 438
 439                   block = BLOCK_SUPERCONTEXT (block);
 440                 }
 441               if (fndecl)
 442                 abstract_origin = block;
 443               else
 444                 {
 445                   while (block && TREE_CODE (block) == BLOCK)
 446                     block = BLOCK_SUPERCONTEXT (block);
 447
 448                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 449                     fndecl = block;
 450                   abstract_origin = NULL;
 451                 }
 452               if (fndecl)
 453                 {
 454                   expanded_location s = expand_location (*locus);
 455                   pp_character (context->printer, ',');
 456                   pp_newline (context->printer);
 457                   if (s.file != NULL)
 458                     {
 459                       if (context->show_column)
 460                         pp_printf (context->printer,
 461                                    _("    inlined from %qs at %s:%d:%d"),
 462                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 463                                    s.file, s.line, s.column);
 464                       else
 465                         pp_printf (context->printer,
 466                                    _("    inlined from %qs at %s:%d"),
 467                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 468                                    s.file, s.line);
 469
 470                     }
 471                   else
 472                     pp_printf (context->printer, _("    inlined from %qs"),
 473                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 474                 }
 475             }
 476           pp_character (context->printer, ':');
 477         }
 478
 479       diagnostic_set_last_function (context, diagnostic);
 480       pp_flush (context->printer);
 481       context->printer->prefix = old_prefix;
 482       free ((char*) new_prefix);
 483     }
 484 }
 485
 486 tree
 487 lhd_callgraph_analyze_expr (tree *tp ATTRIBUTE_UNUSED,
 488                             int *walk_subtrees ATTRIBUTE_UNUSED)
 489 {
 490   return NULL;
 491 }
 492
 493 tree
 494 lhd_make_node (enum tree_code code)
 495 {
 496   return make_node (code);
 497 }
 498
 499 HOST_WIDE_INT
 500 lhd_to_target_charset (HOST_WIDE_INT c)
 501 {
 502   return c;
 503 }
 504
 505 tree
 506 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 507 {
 508   return expr;
 509 }
 510
 511 /* Return sharing kind if OpenMP sharing attribute of DECL is
 512    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 513
 514 enum omp_clause_default_kind
 515 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 516 {
 517   if (DECL_ARTIFICIAL (decl))
 518     return OMP_CLAUSE_DEFAULT_SHARED;
 519   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 520 }
 521
 522 /* Generate code to copy SRC to DST.  */
 523
 524 tree
 525 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 526 {
 527   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 528 }
 529
 530 /* Register language specific type size variables as potentially OpenMP
 531    firstprivate variables.  */
 532
 533 void
 534 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 535                                    tree t ATTRIBUTE_UNUSED)
 536 {
 537 }
 538
 539 /* Common function for add_builtin_function and
 540    add_builtin_function_ext_scope.  */
 541 static tree
 542 add_builtin_function_common (const char *name,
 543                              tree type,
 544                              int function_code,
 545                              enum built_in_class cl,
 546                              const char *library_name,
 547                              tree attrs,
 548                              tree (*hook) (tree))
 549 {
 550   tree   id = get_identifier (name);
 551   tree decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, id, type);
 552
 553   TREE_PUBLIC (decl)         = 1;
 554   DECL_EXTERNAL (decl)       = 1;
 555   DECL_BUILT_IN_CLASS (decl) = cl;
 556
 557   DECL_FUNCTION_CODE (decl)  = (enum built_in_function) function_code;
 558
 559   /* DECL_FUNCTION_CODE is a bitfield; verify that the value fits.  */
 560   gcc_assert (DECL_FUNCTION_CODE (decl) == function_code);
 561
 562   if (library_name)
 563     {
 564       tree libname = get_identifier (library_name);
 565       SET_DECL_ASSEMBLER_NAME (decl, libname);
 566     }
 567
 568   /* Possibly apply some default attributes to this built-in function.  */
 569   if (attrs)
 570     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 571   else
 572     decl_attributes (&decl, NULL_TREE, 0);
 573
 574   return hook (decl);
 575
 576 }
 577
 578 /* Create a builtin function.  */
 579
 580 tree
 581 add_builtin_function (const char *name,
 582                       tree type,
 583                       int function_code,
 584                       enum built_in_class cl,
 585                       const char *library_name,
 586                       tree attrs)
 587 {
 588   return add_builtin_function_common (name, type, function_code, cl,
 589                                       library_name, attrs,
 590                                       lang_hooks.builtin_function);
 591 }
 592
 593 /* Like add_builtin_function, but make sure the scope is the external scope.
 594    This is used to delay putting in back end builtin functions until the ISA
 595    that defines the builtin is declared via function specific target options,
 596    which can save memory for machines like the x86_64 that have multiple ISAs.
 597    If this points to the same function as builtin_function, the backend must
 598    add all of the builtins at program initialization time.  */
 599
 600 tree
 601 add_builtin_function_ext_scope (const char *name,
 602                                 tree type,
 603                                 int function_code,
 604                                 enum built_in_class cl,
 605                                 const char *library_name,
 606                                 tree attrs)
 607 {
 608   return add_builtin_function_common (name, type, function_code, cl,
 609                                       library_name, attrs,
 610                                       lang_hooks.builtin_function_ext_scope);
 611 }
 612
 613 tree
 614 lhd_builtin_function (tree decl)
 615 {
 616   lang_hooks.decls.pushdecl (decl);
 617   return decl;
 618 }
 619
 620 /* LTO hooks.  */
 621
 622 /* Used to save and restore any previously active section.  */
 623 static section *saved_section;
 624
 625
 626 /* Begin a new LTO output section named NAME.  This default implementation
 627    saves the old section and emits assembly code to switch to the new
 628    section.  */
 629
 630 void
 631 lhd_begin_section (const char *name)
 632 {
 633   section *section;
 634
 635   /* Save the old section so we can restore it in lto_end_asm_section.  */
 636   gcc_assert (!saved_section);
 637   saved_section = in_section;
 638   if (!saved_section)
 639     saved_section = text_section;
 640
 641   /* Create a new section and switch to it.  */
 642   section = get_section (name, SECTION_DEBUG, NULL);
 643   switch_to_section (section);
 644 }
 645
 646
 647 /* Write DATA of length LEN to the current LTO output section.  This default
 648    implementation just calls assemble_string and frees BLOCK.  */
 649
 650 void
 651 lhd_append_data (const void *data, size_t len, void *block)
 652 {
 653   if (data)
 654     assemble_string ((const char *)data, len);
 655   free (block);
 656 }
 657
 658
 659 /* Finish the current LTO output section.  This default implementation emits
 660    assembly code to switch to any section previously saved by
 661    lhd_begin_section.  */
 662
 663 void
 664 lhd_end_section (void)
 665 {
 666   if (saved_section)
 667     {
 668       switch_to_section (saved_section);
 669       saved_section = NULL;
 670     }
 671 }