gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   3    Contributed by Alexandre Oliva  <aoliva@redhat.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  20 Boston, MA 02110-1301, USA.  */
  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 "tree-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 "langhooks-def.h"
  37 #include "ggc.h"
  38 #include "diagnostic.h"
  39
  40 /* Do nothing; in many cases the default hook.  */
  41
  42 void
  43 lhd_do_nothing (void)
  44 {
  45 }
  46
  47 /* Do nothing (tree).  */
  48
  49 void
  50 lhd_do_nothing_t (tree ARG_UNUSED (t))
  51 {
  52 }
  53
  54 /* Do nothing (int).  */
  55
  56 void
  57 lhd_do_nothing_i (int ARG_UNUSED (i))
  58 {
  59 }
  60
  61 /* Do nothing (int, int, int).  Return NULL_TREE.  */
  62
  63 tree
  64 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  65                                      int ARG_UNUSED (j),
  66                                      int ARG_UNUSED (k))
  67 {
  68   return NULL_TREE;
  69 }
  70
  71 /* Do nothing (function).  */
  72
  73 void
  74 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  75 {
  76 }
  77
  78 /* Do nothing (return the tree node passed).  */
  79
  80 tree
  81 lhd_return_tree (tree t)
  82 {
  83   return t;
  84 }
  85
  86 /* Do nothing (return NULL_TREE).  */
  87
  88 tree
  89 lhd_return_null_tree_v (void)
  90 {
  91   return NULL_TREE;
  92 }
  93
  94 /* Do nothing (return NULL_TREE).  */
  95
  96 tree
  97 lhd_return_null_tree (tree ARG_UNUSED (t))
  98 {
  99   return NULL_TREE;
 100 }
 101
 102 /* The default post options hook.  */
 103
 104 bool
 105 lhd_post_options (const char ** ARG_UNUSED (pfilename))
 106 {
 107   return false;
 108 }
 109
 110 /* Called from by print-tree.c.  */
 111
 112 void
 113 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 114                         tree ARG_UNUSED (node),
 115                         int ARG_UNUSED (indent))
 116 {
 117 }
 118
 119 /* Called from safe_from_p.  */
 120
 121 int
 122 lhd_safe_from_p (rtx ARG_UNUSED (x), tree ARG_UNUSED (exp))
 123 {
 124   return 1;
 125 }
 126
 127 /* Called from staticp.  */
 128
 129 tree
 130 lhd_staticp (tree ARG_UNUSED (exp))
 131 {
 132   return NULL;
 133 }
 134
 135 /* Called from check_global_declarations.  */
 136
 137 bool
 138 lhd_warn_unused_global_decl (tree decl)
 139 {
 140   /* This is what used to exist in check_global_declarations.  Probably
 141      not many of these actually apply to non-C languages.  */
 142
 143   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_INLINE (decl))
 144     return false;
 145   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 146     return false;
 147   if (DECL_IN_SYSTEM_HEADER (decl))
 148     return false;
 149
 150   return true;
 151 }
 152
 153 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 154 void
 155 lhd_set_decl_assembler_name (tree decl)
 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.
 172
 173      Can't use just the variable's own name for a variable whose scope
 174      is less than the whole compilation.  Concatenate a distinguishing
 175      number - we use the DECL_UID.  */
 176   if (TREE_PUBLIC (decl) || DECL_CONTEXT (decl) == NULL_TREE)
 177     SET_DECL_ASSEMBLER_NAME (decl, DECL_NAME (decl));
 178   else
 179     {
 180       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 181       char *label;
 182
 183       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 184       SET_DECL_ASSEMBLER_NAME (decl, get_identifier (label));
 185     }
 186 }
 187
 188 /* By default we always allow bit-field based optimizations.  */
 189 bool
 190 lhd_can_use_bit_fields_p (void)
 191 {
 192   return true;
 193 }
 194
 195 /* Type promotion for variable arguments.  */
 196 tree
 197 lhd_type_promotes_to (tree ARG_UNUSED (type))
 198 {
 199   gcc_unreachable ();
 200 }
 201
 202 /* Registration of machine- or os-specific builtin types.  */
 203 void
 204 lhd_register_builtin_type (tree ARG_UNUSED (type),
 205                            const char * ARG_UNUSED (name))
 206 {
 207 }
 208
 209 /* Invalid use of an incomplete type.  */
 210 void
 211 lhd_incomplete_type_error (tree ARG_UNUSED (value), tree type)
 212 {
 213   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 214   return;
 215 }
 216
 217 /* Provide a default routine for alias sets that always returns -1.  This
 218    is used by languages that don't need to do anything special.  */
 219
 220 HOST_WIDE_INT
 221 lhd_get_alias_set (tree ARG_UNUSED (t))
 222 {
 223   return -1;
 224 }
 225
 226 /* Provide a hook routine for alias sets that always returns 0.  This is
 227    used by languages that haven't deal with alias sets yet.  */
 228
 229 HOST_WIDE_INT
 230 hook_get_alias_set_0 (tree ARG_UNUSED (t))
 231 {
 232   return 0;
 233 }
 234
 235 /* This is the default expand_expr function.  */
 236
 237 rtx
 238 lhd_expand_expr (tree ARG_UNUSED (t), rtx ARG_UNUSED (r),
 239                  enum machine_mode ARG_UNUSED (mm),
 240                  int ARG_UNUSED (em),
 241                  rtx * ARG_UNUSED (a))
 242 {
 243   gcc_unreachable ();
 244 }
 245
 246 /* The default language-specific function for expanding a decl.  After
 247    the language-independent cases are handled, this function will be
 248    called.  If this function is not defined, it is assumed that
 249    declarations other than those for variables and labels do not require
 250    any RTL generation.  */
 251
 252 int
 253 lhd_expand_decl (tree ARG_UNUSED (t))
 254 {
 255   return 0;
 256 }
 257
 258 /* This is the default decl_printable_name function.  */
 259
 260 const char *
 261 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 262 {
 263   gcc_assert (decl && DECL_NAME (decl));
 264   return IDENTIFIER_POINTER (DECL_NAME (decl));
 265 }
 266
 267 /* This compares two types for equivalence ("compatible" in C-based languages).
 268    This routine should only return 1 if it is sure.  It should not be used
 269    in contexts where erroneously returning 0 causes problems.  */
 270
 271 int
 272 lhd_types_compatible_p (tree x, tree y)
 273 {
 274   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 275 }
 276
 277 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 278    after handling common cases, but before walking code-specific
 279    sub-trees.  If this hook is overridden for a language, it should
 280    handle language-specific tree codes, as well as language-specific
 281    information associated to common tree codes.  If a tree node is
 282    completely handled within this function, it should set *SUBTREES to
 283    0, so that generic handling isn't attempted.  The generic handling
 284    cannot deal with language-specific tree codes, so make sure it is
 285    set properly.  Both SUBTREES and *SUBTREES is guaranteed to be
 286    nonzero when the function is called.  */
 287
 288 tree
 289 lhd_tree_inlining_walk_subtrees (tree *tp ATTRIBUTE_UNUSED,
 290                                  int *subtrees ATTRIBUTE_UNUSED,
 291                                  walk_tree_fn func ATTRIBUTE_UNUSED,
 292                                  void *data ATTRIBUTE_UNUSED,
 293                                  struct pointer_set_t *pset ATTRIBUTE_UNUSED)
 294 {
 295   return NULL_TREE;
 296 }
 297
 298 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 299    determine whether there are language-specific reasons for not
 300    inlining a given function.  */
 301
 302 int
 303 lhd_tree_inlining_cannot_inline_tree_fn (tree *fnp)
 304 {
 305   if (flag_really_no_inline
 306       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 307     return 1;
 308
 309   return 0;
 310 }
 311
 312 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 313    determine whether a function should be considered for inlining even
 314    if it would exceed inlining limits.  */
 315
 316 int
 317 lhd_tree_inlining_disregard_inline_limits (tree fn)
 318 {
 319   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 320     return 1;
 321
 322   return 0;
 323 }
 324
 325 /* lang_hooks.tree_inlining.add_pending_fn_decls is called before
 326    starting to inline a function, to push any language-specific
 327    functions that should not be inlined into the current function,
 328    into VAFNP.  PFN is the top of varray, and should be returned if no
 329    functions are pushed into VAFNP.  The top of the varray should be
 330    returned.  */
 331
 332 tree
 333 lhd_tree_inlining_add_pending_fn_decls (void *vafnp ATTRIBUTE_UNUSED, tree pfn)
 334 {
 335   return pfn;
 336 }
 337
 338 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 339    whether VT is an automatic variable defined in function FT.  */
 340
 341 int
 342 lhd_tree_inlining_auto_var_in_fn_p (tree var, tree fn)
 343 {
 344   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 345           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 346                && ! TREE_STATIC (var))
 347               || TREE_CODE (var) == LABEL_DECL
 348               || TREE_CODE (var) == RESULT_DECL));
 349 }
 350
 351 /* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
 352    type node representing an anonymous aggregate (union, struct, etc),
 353    i.e., one whose members are in the same scope as the union itself.  */
 354
 355 int
 356 lhd_tree_inlining_anon_aggr_type_p (tree t ATTRIBUTE_UNUSED)
 357 {
 358   return 0;
 359 }
 360
 361 /* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
 362    language-specific bookkeeping necessary for processing
 363    FN. start_inlining returns nonzero if inlining should proceed, zero if
 364    not.
 365
 366    For instance, the C++ version keeps track of template instantiations to
 367    avoid infinite recursion.  */
 368
 369 int
 370 lhd_tree_inlining_start_inlining (tree fn ATTRIBUTE_UNUSED)
 371 {
 372   return 1;
 373 }
 374
 375 void
 376 lhd_tree_inlining_end_inlining (tree fn ATTRIBUTE_UNUSED)
 377 {
 378 }
 379
 380 /* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
 381    language-specific conversion before assigning VALUE to PARM.  */
 382
 383 tree
 384 lhd_tree_inlining_convert_parm_for_inlining (tree parm ATTRIBUTE_UNUSED,
 385                                              tree value,
 386                                              tree fndecl ATTRIBUTE_UNUSED,
 387                                              int argnum ATTRIBUTE_UNUSED)
 388 {
 389   return value;
 390 }
 391
 392 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 393    nodes.  Returns nonzero if it does not want the usual dumping of the
 394    second argument.  */
 395
 396 bool
 397 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 398 {
 399   return false;
 400 }
 401
 402 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 403    language-specific way.  */
 404
 405 int
 406 lhd_tree_dump_type_quals (tree t)
 407 {
 408   return TYPE_QUALS (t);
 409 }
 410
 411 /* lang_hooks.expr_size: Determine the size of the value of an expression T
 412    in a language-specific way.  Returns a tree for the size in bytes.  */
 413
 414 tree
 415 lhd_expr_size (tree exp)
 416 {
 417   if (DECL_P (exp)
 418       && DECL_SIZE_UNIT (exp) != 0)
 419     return DECL_SIZE_UNIT (exp);
 420   else
 421     return size_in_bytes (TREE_TYPE (exp));
 422 }
 423
 424 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 425
 426 int
 427 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED, tree *pre_p ATTRIBUTE_UNUSED,
 428                    tree *post_p ATTRIBUTE_UNUSED)
 429 {
 430   return GS_UNHANDLED;
 431 }
 432
 433 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 434    which is a language-specific tree code in category tcc_constant or
 435    tcc_exceptional.  The default expects never to be called.  */
 436 size_t
 437 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 438 {
 439   gcc_unreachable ();
 440 }
 441
 442 /* Return true if decl, which is a function decl, may be called by a
 443    sibcall.  */
 444
 445 bool
 446 lhd_decl_ok_for_sibcall (tree decl ATTRIBUTE_UNUSED)
 447 {
 448   return true;
 449 }
 450
 451 /* Return the COMDAT group into which DECL should be placed.  */
 452
 453 const char *
 454 lhd_comdat_group (tree decl)
 455 {
 456   return IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
 457 }
 458
 459 /* lang_hooks.decls.final_write_globals: perform final processing on
 460    global variables.  */
 461 void
 462 write_global_declarations (void)
 463 {
 464   /* Really define vars that have had only a tentative definition.
 465      Really output inline functions that must actually be callable
 466      and have not been output so far.  */
 467
 468   tree globals = lang_hooks.decls.getdecls ();
 469   int len = list_length (globals);
 470   tree *vec = XNEWVEC (tree, len);
 471   int i;
 472   tree decl;
 473
 474   /* Process the decls in reverse order--earliest first.
 475      Put them into VEC from back to front, then take out from front.  */
 476
 477   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
 478     vec[len - i - 1] = decl;
 479
 480   wrapup_global_declarations (vec, len);
 481   check_global_declarations (vec, len);
 482   emit_debug_global_declarations (vec, len);
 483
 484   /* Clean up.  */
 485   free (vec);
 486 }
 487
 488 /* Called to perform language-specific initialization of CTX.  */
 489 void
 490 lhd_initialize_diagnostics (struct diagnostic_context *ctx ATTRIBUTE_UNUSED)
 491 {
 492 }
 493
 494 /* The default function to print out name of current function that caused
 495    an error.  */
 496 void
 497 lhd_print_error_function (diagnostic_context *context, const char *file)
 498 {
 499   if (diagnostic_last_function_changed (context))
 500     {
 501       const char *old_prefix = context->printer->prefix;
 502       char *new_prefix = file ? file_name_as_prefix (file) : NULL;
 503
 504       pp_set_prefix (context->printer, new_prefix);
 505
 506       if (current_function_decl == NULL)
 507         pp_printf (context->printer, _("At top level:"));
 508       else
 509         {
 510           if (TREE_CODE (TREE_TYPE (current_function_decl)) == METHOD_TYPE)
 511             pp_printf
 512               (context->printer, _("In member function %qs:"),
 513                lang_hooks.decl_printable_name (current_function_decl, 2));
 514           else
 515             pp_printf
 516               (context->printer, _("In function %qs:"),
 517                lang_hooks.decl_printable_name (current_function_decl, 2));
 518         }
 519
 520       diagnostic_set_last_function (context);
 521       pp_flush (context->printer);
 522       context->printer->prefix = old_prefix;
 523       free ((char*) new_prefix);
 524     }
 525 }
 526
 527 tree
 528 lhd_callgraph_analyze_expr (tree *tp ATTRIBUTE_UNUSED,
 529                             int *walk_subtrees ATTRIBUTE_UNUSED,
 530                             tree decl ATTRIBUTE_UNUSED)
 531 {
 532   return NULL;
 533 }
 534
 535 tree
 536 lhd_make_node (enum tree_code code)
 537 {
 538   return make_node (code);
 539 }
 540
 541 HOST_WIDE_INT
 542 lhd_to_target_charset (HOST_WIDE_INT c)
 543 {
 544   return c;
 545 }
 546
 547 tree
 548 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
 549                   bool *ti ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 550 {
 551   return expr;
 552 }
 553
 554 /* Return sharing kind if OpenMP sharing attribute of DECL is
 555    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 556
 557 enum omp_clause_default_kind
 558 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 559 {
 560   if (DECL_ARTIFICIAL (decl))
 561     return OMP_CLAUSE_DEFAULT_SHARED;
 562   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 563 }
 564
 565 /* Generate code to copy SRC to DST.  */
 566
 567 tree
 568 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 569 {
 570   return build2 (MODIFY_EXPR, void_type_node, dst, src);
 571 }
 572
 573 /* Register language specific type size variables as potentially OpenMP
 574    firstprivate variables.  */
 575
 576 void
 577 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 578                                    tree t ATTRIBUTE_UNUSED)
 579 {
 580 }