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, int, int).  Return NULL_TREE.  */
  66
  67 tree
  68 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  69                                      int ARG_UNUSED (j),
  70                                      int ARG_UNUSED (k))
  71 {
  72   return NULL_TREE;
  73 }
  74
  75 /* Do nothing (function).  */
  76
  77 void
  78 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  79 {
  80 }
  81
  82 /* Do nothing (return NULL_TREE).  */
  83
  84 tree
  85 lhd_return_null_tree_v (void)
  86 {
  87   return NULL_TREE;
  88 }
  89
  90 /* Do nothing (return NULL_TREE).  */
  91
  92 tree
  93 lhd_return_null_tree (tree ARG_UNUSED (t))
  94 {
  95   return NULL_TREE;
  96 }
  97
  98 /* Do nothing (return NULL_TREE).  */
  99
 100 tree
 101 lhd_return_null_const_tree (const_tree ARG_UNUSED (t))
 102 {
 103   return NULL_TREE;
 104 }
 105
 106 /* The default post options hook.  */
 107
 108 bool
 109 lhd_post_options (const char ** ARG_UNUSED (pfilename))
 110 {
 111   /* Excess precision other than "fast" requires front-end
 112      support.  */
 113   flag_excess_precision_cmdline = EXCESS_PRECISION_FAST;
 114   return false;
 115 }
 116
 117 /* Called from by print-tree.c.  */
 118
 119 void
 120 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 121                         tree ARG_UNUSED (node),
 122                         int ARG_UNUSED (indent))
 123 {
 124 }
 125
 126 /* Called from check_global_declarations.  */
 127
 128 bool
 129 lhd_warn_unused_global_decl (const_tree decl)
 130 {
 131   /* This is what used to exist in check_global_declarations.  Probably
 132      not many of these actually apply to non-C languages.  */
 133
 134   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 135     return false;
 136   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 137     return false;
 138   if (DECL_IN_SYSTEM_HEADER (decl))
 139     return false;
 140
 141   return true;
 142 }
 143
 144 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 145 void
 146 lhd_set_decl_assembler_name (tree decl)
 147 {
 148   tree id;
 149
 150   /* The language-independent code should never use the
 151      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 152      VAR_DECLs for variables with static storage duration need a real
 153      DECL_ASSEMBLER_NAME.  */
 154   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 155               || (TREE_CODE (decl) == VAR_DECL
 156                   && (TREE_STATIC (decl)
 157                       || DECL_EXTERNAL (decl)
 158                       || TREE_PUBLIC (decl))));
 159
 160   /* By default, assume the name to use in assembly code is the same
 161      as that used in the source language.  (That's correct for C, and
 162      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 163      DECL_NAME in build_decl, so this choice provides backwards
 164      compatibility with existing front-ends.  This assumption is wrapped
 165      in a target hook, to allow for target-specific modification of the
 166      identifier.
 167
 168      Can't use just the variable's own name for a variable whose scope
 169      is less than the whole compilation.  Concatenate a distinguishing
 170      number - we use the DECL_UID.  */
 171
 172   if (TREE_PUBLIC (decl) || DECL_FILE_SCOPE_P (decl))
 173     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 174   else
 175     {
 176       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 177       char *label;
 178
 179       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 180       id = get_identifier (label);
 181     }
 182   SET_DECL_ASSEMBLER_NAME (decl, id);
 183
 184 }
 185
 186 /* Type promotion for variable arguments.  */
 187 tree
 188 lhd_type_promotes_to (tree ARG_UNUSED (type))
 189 {
 190   gcc_unreachable ();
 191 }
 192
 193 /* Registration of machine- or os-specific builtin types.  */
 194 void
 195 lhd_register_builtin_type (tree ARG_UNUSED (type),
 196                            const char * ARG_UNUSED (name))
 197 {
 198 }
 199
 200 /* Invalid use of an incomplete type.  */
 201 void
 202 lhd_incomplete_type_error (const_tree ARG_UNUSED (value), const_tree type)
 203 {
 204   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 205   return;
 206 }
 207
 208 /* Provide a default routine for alias sets that always returns -1.  This
 209    is used by languages that don't need to do anything special.  */
 210
 211 alias_set_type
 212 lhd_get_alias_set (tree ARG_UNUSED (t))
 213 {
 214   return -1;
 215 }
 216
 217 /* This is the default decl_printable_name function.  */
 218
 219 const char *
 220 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 221 {
 222   gcc_assert (decl && DECL_NAME (decl));
 223   return IDENTIFIER_POINTER (DECL_NAME (decl));
 224 }
 225
 226 /* This is the default dwarf_name function.  */
 227
 228 const char *
 229 lhd_dwarf_name (tree t, int verbosity)
 230 {
 231   gcc_assert (DECL_P (t));
 232
 233   return lang_hooks.decl_printable_name (t, verbosity);
 234 }
 235
 236 /* This compares two types for equivalence ("compatible" in C-based languages).
 237    This routine should only return 1 if it is sure.  It should not be used
 238    in contexts where erroneously returning 0 causes problems.  */
 239
 240 int
 241 lhd_types_compatible_p (tree x, tree y)
 242 {
 243   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 244 }
 245
 246 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 247    nodes.  Returns nonzero if it does not want the usual dumping of the
 248    second argument.  */
 249
 250 bool
 251 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 252 {
 253   return false;
 254 }
 255
 256 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 257    language-specific way.  */
 258
 259 int
 260 lhd_tree_dump_type_quals (const_tree t)
 261 {
 262   return TYPE_QUALS (t);
 263 }
 264
 265 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 266
 267 int
 268 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED,
 269                    gimple_seq *pre_p ATTRIBUTE_UNUSED,
 270                    gimple_seq *post_p ATTRIBUTE_UNUSED)
 271 {
 272   return GS_UNHANDLED;
 273 }
 274
 275 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 276    which is a language-specific tree code in category tcc_constant or
 277    tcc_exceptional.  The default expects never to be called.  */
 278 size_t
 279 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 280 {
 281   gcc_unreachable ();
 282 }
 283
 284 /* Return true if decl, which is a function decl, may be called by a
 285    sibcall.  */
 286
 287 bool
 288 lhd_decl_ok_for_sibcall (const_tree decl ATTRIBUTE_UNUSED)
 289 {
 290   return true;
 291 }
 292
 293 /* lang_hooks.decls.final_write_globals: perform final processing on
 294    global variables.  */
 295 void
 296 write_global_declarations (void)
 297 {
 298   tree globals, decl, *vec;
 299   int len, i;
 300
 301   /* This lang hook is dual-purposed, and also finalizes the
 302      compilation unit.  */
 303   cgraph_finalize_compilation_unit ();
 304
 305   /* Really define vars that have had only a tentative definition.
 306      Really output inline functions that must actually be callable
 307      and have not been output so far.  */
 308
 309   globals = lang_hooks.decls.getdecls ();
 310   len = list_length (globals);
 311   vec = XNEWVEC (tree, len);
 312
 313   /* Process the decls in reverse order--earliest first.
 314      Put them into VEC from back to front, then take out from front.  */
 315
 316   for (i = 0, decl = globals; i < len; i++, decl = DECL_CHAIN (decl))
 317     vec[len - i - 1] = decl;
 318
 319   wrapup_global_declarations (vec, len);
 320   check_global_declarations (vec, len);
 321   emit_debug_global_declarations (vec, len);
 322
 323   /* Clean up.  */
 324   free (vec);
 325 }
 326
 327 /* Called to perform language-specific initialization of CTX.  */
 328 void
 329 lhd_initialize_diagnostics (diagnostic_context *ctx ATTRIBUTE_UNUSED)
 330 {
 331 }
 332
 333 /* Called to perform language-specific options initialization.  */
 334 void
 335 lhd_init_options (unsigned int decoded_options_count ATTRIBUTE_UNUSED,
 336                   struct cl_decoded_option *decoded_options ATTRIBUTE_UNUSED)
 337 {
 338 }
 339
 340 /* By default, always complain about options for the wrong language.  */
 341 bool
 342 lhd_complain_wrong_lang_p (const struct cl_option *option ATTRIBUTE_UNUSED)
 343 {
 344   return true;
 345 }
 346
 347 /* By default, no language-specific options are valid.  */
 348 bool
 349 lhd_handle_option (size_t code ATTRIBUTE_UNUSED,
 350                    const char *arg ATTRIBUTE_UNUSED,
 351                    int value ATTRIBUTE_UNUSED, int kind ATTRIBUTE_UNUSED,
 352                    location_t loc ATTRIBUTE_UNUSED,
 353                    const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 354 {
 355   return false;
 356 }
 357
 358 /* The default function to print out name of current function that caused
 359    an error.  */
 360 void
 361 lhd_print_error_function (diagnostic_context *context, const char *file,
 362                           diagnostic_info *diagnostic)
 363 {
 364   if (diagnostic_last_function_changed (context, diagnostic))
 365     {
 366       const char *old_prefix = context->printer->prefix;
 367       tree abstract_origin = diagnostic_abstract_origin (diagnostic);
 368       char *new_prefix = (file && abstract_origin == NULL)
 369                          ? file_name_as_prefix (file) : NULL;
 370
 371       pp_set_prefix (context->printer, new_prefix);
 372
 373       if (current_function_decl == NULL)
 374         pp_printf (context->printer, _("At top level:"));
 375       else
 376         {
 377           tree fndecl, ao;
 378
 379           if (abstract_origin)
 380             {
 381               ao = BLOCK_ABSTRACT_ORIGIN (abstract_origin);
 382               while (TREE_CODE (ao) == BLOCK
 383                      && BLOCK_ABSTRACT_ORIGIN (ao)
 384                      && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 385                 ao = BLOCK_ABSTRACT_ORIGIN (ao);
 386               gcc_assert (TREE_CODE (ao) == FUNCTION_DECL);
 387               fndecl = ao;
 388             }
 389           else
 390             fndecl = current_function_decl;
 391
 392           if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
 393             pp_printf
 394               (context->printer, _("In member function %qs"),
 395                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 396           else
 397             pp_printf
 398               (context->printer, _("In function %qs"),
 399                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 400
 401           while (abstract_origin)
 402             {
 403               location_t *locus;
 404               tree block = abstract_origin;
 405
 406               locus = &BLOCK_SOURCE_LOCATION (block);
 407               fndecl = NULL;
 408               block = BLOCK_SUPERCONTEXT (block);
 409               while (block && TREE_CODE (block) == BLOCK
 410                      && BLOCK_ABSTRACT_ORIGIN (block))
 411                 {
 412                   ao = BLOCK_ABSTRACT_ORIGIN (block);
 413
 414                   while (TREE_CODE (ao) == BLOCK
 415                          && BLOCK_ABSTRACT_ORIGIN (ao)
 416                          && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
 417                     ao = BLOCK_ABSTRACT_ORIGIN (ao);
 418
 419                   if (TREE_CODE (ao) == FUNCTION_DECL)
 420                     {
 421                       fndecl = ao;
 422                       break;
 423                     }
 424                   else if (TREE_CODE (ao) != BLOCK)
 425                     break;
 426
 427                   block = BLOCK_SUPERCONTEXT (block);
 428                 }
 429               if (fndecl)
 430                 abstract_origin = block;
 431               else
 432                 {
 433                   while (block && TREE_CODE (block) == BLOCK)
 434                     block = BLOCK_SUPERCONTEXT (block);
 435
 436                   if (block && TREE_CODE (block) == FUNCTION_DECL)
 437                     fndecl = block;
 438                   abstract_origin = NULL;
 439                 }
 440               if (fndecl)
 441                 {
 442                   expanded_location s = expand_location (*locus);
 443                   pp_character (context->printer, ',');
 444                   pp_newline (context->printer);
 445                   if (s.file != NULL)
 446                     {
 447                       if (context->show_column)
 448                         pp_printf (context->printer,
 449                                    _("    inlined from %qs at %s:%d:%d"),
 450                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 451                                    s.file, s.line, s.column);
 452                       else
 453                         pp_printf (context->printer,
 454                                    _("    inlined from %qs at %s:%d"),
 455                                    identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)),
 456                                    s.file, s.line);
 457
 458                     }
 459                   else
 460                     pp_printf (context->printer, _("    inlined from %qs"),
 461                                identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 2)));
 462                 }
 463             }
 464           pp_character (context->printer, ':');
 465         }
 466
 467       diagnostic_set_last_function (context, diagnostic);
 468       pp_flush (context->printer);
 469       context->printer->prefix = old_prefix;
 470       free ((char*) new_prefix);
 471     }
 472 }
 473
 474 tree
 475 lhd_callgraph_analyze_expr (tree *tp ATTRIBUTE_UNUSED,
 476                             int *walk_subtrees ATTRIBUTE_UNUSED)
 477 {
 478   return NULL;
 479 }
 480
 481 tree
 482 lhd_make_node (enum tree_code code)
 483 {
 484   return make_node (code);
 485 }
 486
 487 HOST_WIDE_INT
 488 lhd_to_target_charset (HOST_WIDE_INT c)
 489 {
 490   return c;
 491 }
 492
 493 tree
 494 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 495 {
 496   return expr;
 497 }
 498
 499 /* Return sharing kind if OpenMP sharing attribute of DECL is
 500    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 501
 502 enum omp_clause_default_kind
 503 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 504 {
 505   if (DECL_ARTIFICIAL (decl))
 506     return OMP_CLAUSE_DEFAULT_SHARED;
 507   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 508 }
 509
 510 /* Generate code to copy SRC to DST.  */
 511
 512 tree
 513 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 514 {
 515   return build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
 516 }
 517
 518 /* Register language specific type size variables as potentially OpenMP
 519    firstprivate variables.  */
 520
 521 void
 522 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 523                                    tree t ATTRIBUTE_UNUSED)
 524 {
 525 }
 526
 527 /* Common function for add_builtin_function and
 528    add_builtin_function_ext_scope.  */
 529 static tree
 530 add_builtin_function_common (const char *name,
 531                              tree type,
 532                              int function_code,
 533                              enum built_in_class cl,
 534                              const char *library_name,
 535                              tree attrs,
 536                              tree (*hook) (tree))
 537 {
 538   tree   id = get_identifier (name);
 539   tree decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, id, type);
 540
 541   TREE_PUBLIC (decl)         = 1;
 542   DECL_EXTERNAL (decl)       = 1;
 543   DECL_BUILT_IN_CLASS (decl) = cl;
 544
 545   DECL_FUNCTION_CODE (decl)  = (enum built_in_function) function_code;
 546
 547   /* DECL_FUNCTION_CODE is a bitfield; verify that the value fits.  */
 548   gcc_assert (DECL_FUNCTION_CODE (decl) == function_code);
 549
 550   if (library_name)
 551     {
 552       tree libname = get_identifier (library_name);
 553       SET_DECL_ASSEMBLER_NAME (decl, libname);
 554     }
 555
 556   /* Possibly apply some default attributes to this built-in function.  */
 557   if (attrs)
 558     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 559   else
 560     decl_attributes (&decl, NULL_TREE, 0);
 561
 562   return hook (decl);
 563
 564 }
 565
 566 /* Create a builtin function.  */
 567
 568 tree
 569 add_builtin_function (const char *name,
 570                       tree type,
 571                       int function_code,
 572                       enum built_in_class cl,
 573                       const char *library_name,
 574                       tree attrs)
 575 {
 576   return add_builtin_function_common (name, type, function_code, cl,
 577                                       library_name, attrs,
 578                                       lang_hooks.builtin_function);
 579 }
 580
 581 /* Like add_builtin_function, but make sure the scope is the external scope.
 582    This is used to delay putting in back end builtin functions until the ISA
 583    that defines the builtin is declared via function specific target options,
 584    which can save memory for machines like the x86_64 that have multiple ISAs.
 585    If this points to the same function as builtin_function, the backend must
 586    add all of the builtins at program initialization time.  */
 587
 588 tree
 589 add_builtin_function_ext_scope (const char *name,
 590                                 tree type,
 591                                 int function_code,
 592                                 enum built_in_class cl,
 593                                 const char *library_name,
 594                                 tree attrs)
 595 {
 596   return add_builtin_function_common (name, type, function_code, cl,
 597                                       library_name, attrs,
 598                                       lang_hooks.builtin_function_ext_scope);
 599 }
 600
 601 tree
 602 lhd_builtin_function (tree decl)
 603 {
 604   lang_hooks.decls.pushdecl (decl);
 605   return decl;
 606 }
 607
 608 /* Create a builtin type.  */
 609
 610 tree
 611 add_builtin_type (const char *name, tree type)
 612 {
 613   tree   id = get_identifier (name);
 614   tree decl = build_decl (BUILTINS_LOCATION, TYPE_DECL, id, type);
 615   return lang_hooks.decls.pushdecl (decl);
 616 }
 617
 618 /* LTO hooks.  */
 619
 620 /* Used to save and restore any previously active section.  */
 621 static section *saved_section;
 622
 623
 624 /* Begin a new LTO output section named NAME.  This default implementation
 625    saves the old section and emits assembly code to switch to the new
 626    section.  */
 627
 628 void
 629 lhd_begin_section (const char *name)
 630 {
 631   section *section;
 632
 633   /* Save the old section so we can restore it in lto_end_asm_section.  */
 634   gcc_assert (!saved_section);
 635   saved_section = in_section;
 636   if (!saved_section)
 637     saved_section = text_section;
 638
 639   /* Create a new section and switch to it.  */
 640   section = get_section (name, SECTION_DEBUG, NULL);
 641   switch_to_section (section);
 642 }
 643
 644
 645 /* Write DATA of length LEN to the current LTO output section.  This default
 646    implementation just calls assemble_string and frees BLOCK.  */
 647
 648 void
 649 lhd_append_data (const void *data, size_t len, void *block)
 650 {
 651   if (data)
 652     assemble_string ((const char *)data, len);
 653   free (block);
 654 }
 655
 656
 657 /* Finish the current LTO output section.  This default implementation emits
 658    assembly code to switch to any section previously saved by
 659    lhd_begin_section.  */
 660
 661 void
 662 lhd_end_section (void)
 663 {
 664   if (saved_section)
 665     {
 666       switch_to_section (saved_section);
 667       saved_section = NULL;
 668     }
 669 }