gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007
   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 2, 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 COPYING.  If not, write to
  20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  21 Boston, MA 02110-1301, USA.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "intl.h"
  27 #include "tm.h"
  28 #include "toplev.h"
  29 #include "tree.h"
  30 #include "tree-inline.h"
  31 #include "tree-gimple.h"
  32 #include "rtl.h"
  33 #include "insn-config.h"
  34 #include "integrate.h"
  35 #include "flags.h"
  36 #include "langhooks.h"
  37 #include "target.h"
  38 #include "langhooks-def.h"
  39 #include "ggc.h"
  40 #include "diagnostic.h"
  41
  42 /* Do nothing; in many cases the default hook.  */
  43
  44 void
  45 lhd_do_nothing (void)
  46 {
  47 }
  48
  49 /* Do nothing (tree).  */
  50
  51 void
  52 lhd_do_nothing_t (tree ARG_UNUSED (t))
  53 {
  54 }
  55
  56 /* Do nothing (int).  */
  57
  58 void
  59 lhd_do_nothing_i (int ARG_UNUSED (i))
  60 {
  61 }
  62
  63 /* Do nothing (int, int, int).  Return NULL_TREE.  */
  64
  65 tree
  66 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  67                                      int ARG_UNUSED (j),
  68                                      int ARG_UNUSED (k))
  69 {
  70   return NULL_TREE;
  71 }
  72
  73 /* Do nothing (function).  */
  74
  75 void
  76 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  77 {
  78 }
  79
  80 /* Do nothing (return the tree node passed).  */
  81
  82 tree
  83 lhd_return_tree (tree t)
  84 {
  85   return t;
  86 }
  87
  88 /* Do nothing (return NULL_TREE).  */
  89
  90 tree
  91 lhd_return_null_tree_v (void)
  92 {
  93   return NULL_TREE;
  94 }
  95
  96 /* Do nothing (return NULL_TREE).  */
  97
  98 tree
  99 lhd_return_null_tree (tree ARG_UNUSED (t))
 100 {
 101   return NULL_TREE;
 102 }
 103
 104 /* The default post options hook.  */
 105
 106 bool
 107 lhd_post_options (const char ** ARG_UNUSED (pfilename))
 108 {
 109   return false;
 110 }
 111
 112 /* Called from by print-tree.c.  */
 113
 114 void
 115 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 116                         tree ARG_UNUSED (node),
 117                         int ARG_UNUSED (indent))
 118 {
 119 }
 120
 121 /* Called from staticp.  */
 122
 123 tree
 124 lhd_staticp (tree ARG_UNUSED (exp))
 125 {
 126   return NULL;
 127 }
 128
 129 /* Called from check_global_declarations.  */
 130
 131 bool
 132 lhd_warn_unused_global_decl (tree decl)
 133 {
 134   /* This is what used to exist in check_global_declarations.  Probably
 135      not many of these actually apply to non-C languages.  */
 136
 137   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_INLINE (decl))
 138     return false;
 139   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 140     return false;
 141   if (DECL_IN_SYSTEM_HEADER (decl))
 142     return false;
 143
 144   return true;
 145 }
 146
 147 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 148 void
 149 lhd_set_decl_assembler_name (tree decl)
 150 {
 151   tree id;
 152
 153   /* The language-independent code should never use the
 154      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 155      VAR_DECLs for variables with static storage duration need a real
 156      DECL_ASSEMBLER_NAME.  */
 157   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 158               || (TREE_CODE (decl) == VAR_DECL
 159                   && (TREE_STATIC (decl)
 160                       || DECL_EXTERNAL (decl)
 161                       || TREE_PUBLIC (decl))));
 162
 163   /* By default, assume the name to use in assembly code is the same
 164      as that used in the source language.  (That's correct for C, and
 165      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 166      DECL_NAME in build_decl, so this choice provides backwards
 167      compatibility with existing front-ends.  This assumption is wrapped
 168      in a target hook, to allow for target-specific modification of the
 169      identifier.
 170
 171      Can't use just the variable's own name for a variable whose scope
 172      is less than the whole compilation.  Concatenate a distinguishing
 173      number - we use the DECL_UID.  */
 174
 175   if (TREE_PUBLIC (decl) || DECL_CONTEXT (decl) == NULL_TREE)
 176     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 177   else
 178     {
 179       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 180       char *label;
 181
 182       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 183       id = get_identifier (label);
 184     }
 185   SET_DECL_ASSEMBLER_NAME (decl, id);
 186
 187 }
 188
 189 /* Type promotion for variable arguments.  */
 190 tree
 191 lhd_type_promotes_to (tree ARG_UNUSED (type))
 192 {
 193   gcc_unreachable ();
 194 }
 195
 196 /* Registration of machine- or os-specific builtin types.  */
 197 void
 198 lhd_register_builtin_type (tree ARG_UNUSED (type),
 199                            const char * ARG_UNUSED (name))
 200 {
 201 }
 202
 203 /* Invalid use of an incomplete type.  */
 204 void
 205 lhd_incomplete_type_error (tree ARG_UNUSED (value), tree type)
 206 {
 207   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 208   return;
 209 }
 210
 211 /* Provide a default routine for alias sets that always returns -1.  This
 212    is used by languages that don't need to do anything special.  */
 213
 214 HOST_WIDE_INT
 215 lhd_get_alias_set (tree ARG_UNUSED (t))
 216 {
 217   return -1;
 218 }
 219
 220 /* This is the default expand_expr function.  */
 221
 222 rtx
 223 lhd_expand_expr (tree ARG_UNUSED (t), rtx ARG_UNUSED (r),
 224                  enum machine_mode ARG_UNUSED (mm),
 225                  int ARG_UNUSED (em),
 226                  rtx * ARG_UNUSED (a))
 227 {
 228   gcc_unreachable ();
 229 }
 230
 231 /* The default language-specific function for expanding a decl.  After
 232    the language-independent cases are handled, this function will be
 233    called.  If this function is not defined, it is assumed that
 234    declarations other than those for variables and labels do not require
 235    any RTL generation.  */
 236
 237 int
 238 lhd_expand_decl (tree ARG_UNUSED (t))
 239 {
 240   return 0;
 241 }
 242
 243 /* This is the default decl_printable_name function.  */
 244
 245 const char *
 246 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 247 {
 248   gcc_assert (decl && DECL_NAME (decl));
 249   return IDENTIFIER_POINTER (DECL_NAME (decl));
 250 }
 251
 252 /* This is the default dwarf_name function.  */
 253
 254 const char *
 255 lhd_dwarf_name (tree t, int verbosity)
 256 {
 257   gcc_assert (DECL_P (t));
 258
 259   return lang_hooks.decl_printable_name (t, verbosity);
 260 }
 261
 262 /* This compares two types for equivalence ("compatible" in C-based languages).
 263    This routine should only return 1 if it is sure.  It should not be used
 264    in contexts where erroneously returning 0 causes problems.  */
 265
 266 int
 267 lhd_types_compatible_p (tree x, tree y)
 268 {
 269   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 270 }
 271
 272 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 273    after handling common cases, but before walking code-specific
 274    sub-trees.  If this hook is overridden for a language, it should
 275    handle language-specific tree codes, as well as language-specific
 276    information associated to common tree codes.  If a tree node is
 277    completely handled within this function, it should set *SUBTREES to
 278    0, so that generic handling isn't attempted.  The generic handling
 279    cannot deal with language-specific tree codes, so make sure it is
 280    set properly.  Both SUBTREES and *SUBTREES is guaranteed to be
 281    nonzero when the function is called.  */
 282
 283 tree
 284 lhd_tree_inlining_walk_subtrees (tree *tp ATTRIBUTE_UNUSED,
 285                                  int *subtrees ATTRIBUTE_UNUSED,
 286                                  walk_tree_fn func ATTRIBUTE_UNUSED,
 287                                  void *data ATTRIBUTE_UNUSED,
 288                                  struct pointer_set_t *pset ATTRIBUTE_UNUSED)
 289 {
 290   return NULL_TREE;
 291 }
 292
 293 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 294    determine whether there are language-specific reasons for not
 295    inlining a given function.  */
 296
 297 int
 298 lhd_tree_inlining_cannot_inline_tree_fn (tree *fnp)
 299 {
 300   if (flag_really_no_inline
 301       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 302     return 1;
 303
 304   return 0;
 305 }
 306
 307 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 308    determine whether a function should be considered for inlining even
 309    if it would exceed inlining limits.  */
 310
 311 int
 312 lhd_tree_inlining_disregard_inline_limits (tree fn)
 313 {
 314   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 315     return 1;
 316
 317   return 0;
 318 }
 319
 320 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 321    whether VT is an automatic variable defined in function FT.  */
 322
 323 int
 324 lhd_tree_inlining_auto_var_in_fn_p (tree var, tree fn)
 325 {
 326   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 327           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 328                && ! TREE_STATIC (var))
 329               || TREE_CODE (var) == LABEL_DECL
 330               || TREE_CODE (var) == RESULT_DECL));
 331 }
 332
 333 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 334    nodes.  Returns nonzero if it does not want the usual dumping of the
 335    second argument.  */
 336
 337 bool
 338 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 339 {
 340   return false;
 341 }
 342
 343 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 344    language-specific way.  */
 345
 346 int
 347 lhd_tree_dump_type_quals (tree t)
 348 {
 349   return TYPE_QUALS (t);
 350 }
 351
 352 /* lang_hooks.expr_size: Determine the size of the value of an expression T
 353    in a language-specific way.  Returns a tree for the size in bytes.  */
 354
 355 tree
 356 lhd_expr_size (tree exp)
 357 {
 358   if (DECL_P (exp)
 359       && DECL_SIZE_UNIT (exp) != 0)
 360     return DECL_SIZE_UNIT (exp);
 361   else
 362     return size_in_bytes (TREE_TYPE (exp));
 363 }
 364
 365 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 366
 367 int
 368 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED, tree *pre_p ATTRIBUTE_UNUSED,
 369                    tree *post_p ATTRIBUTE_UNUSED)
 370 {
 371   return GS_UNHANDLED;
 372 }
 373
 374 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 375    which is a language-specific tree code in category tcc_constant or
 376    tcc_exceptional.  The default expects never to be called.  */
 377 size_t
 378 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 379 {
 380   gcc_unreachable ();
 381 }
 382
 383 /* Return true if decl, which is a function decl, may be called by a
 384    sibcall.  */
 385
 386 bool
 387 lhd_decl_ok_for_sibcall (tree decl ATTRIBUTE_UNUSED)
 388 {
 389   return true;
 390 }
 391
 392 /* Return the COMDAT group into which DECL should be placed.  */
 393
 394 const char *
 395 lhd_comdat_group (tree decl)
 396 {
 397   return IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
 398 }
 399
 400 /* lang_hooks.decls.final_write_globals: perform final processing on
 401    global variables.  */
 402 void
 403 write_global_declarations (void)
 404 {
 405   /* Really define vars that have had only a tentative definition.
 406      Really output inline functions that must actually be callable
 407      and have not been output so far.  */
 408
 409   tree globals = lang_hooks.decls.getdecls ();
 410   int len = list_length (globals);
 411   tree *vec = XNEWVEC (tree, len);
 412   int i;
 413   tree decl;
 414
 415   /* Process the decls in reverse order--earliest first.
 416      Put them into VEC from back to front, then take out from front.  */
 417
 418   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
 419     vec[len - i - 1] = decl;
 420
 421   wrapup_global_declarations (vec, len);
 422   check_global_declarations (vec, len);
 423   emit_debug_global_declarations (vec, len);
 424
 425   /* Clean up.  */
 426   free (vec);
 427 }
 428
 429 /* Called to perform language-specific initialization of CTX.  */
 430 void
 431 lhd_initialize_diagnostics (struct diagnostic_context *ctx ATTRIBUTE_UNUSED)
 432 {
 433 }
 434
 435 /* The default function to print out name of current function that caused
 436    an error.  */
 437 void
 438 lhd_print_error_function (diagnostic_context *context, const char *file)
 439 {
 440   if (diagnostic_last_function_changed (context))
 441     {
 442       const char *old_prefix = context->printer->prefix;
 443       char *new_prefix = file ? file_name_as_prefix (file) : NULL;
 444
 445       pp_set_prefix (context->printer, new_prefix);
 446
 447       if (current_function_decl == NULL)
 448         pp_printf (context->printer, _("At top level:"));
 449       else
 450         {
 451           if (TREE_CODE (TREE_TYPE (current_function_decl)) == METHOD_TYPE)
 452             pp_printf
 453               (context->printer, _("In member function %qs:"),
 454                lang_hooks.decl_printable_name (current_function_decl, 2));
 455           else
 456             pp_printf
 457               (context->printer, _("In function %qs:"),
 458                lang_hooks.decl_printable_name (current_function_decl, 2));
 459         }
 460
 461       diagnostic_set_last_function (context);
 462       pp_flush (context->printer);
 463       context->printer->prefix = old_prefix;
 464       free ((char*) new_prefix);
 465     }
 466 }
 467
 468 tree
 469 lhd_callgraph_analyze_expr (tree *tp ATTRIBUTE_UNUSED,
 470                             int *walk_subtrees ATTRIBUTE_UNUSED,
 471                             tree decl ATTRIBUTE_UNUSED)
 472 {
 473   return NULL;
 474 }
 475
 476 tree
 477 lhd_make_node (enum tree_code code)
 478 {
 479   return make_node (code);
 480 }
 481
 482 HOST_WIDE_INT
 483 lhd_to_target_charset (HOST_WIDE_INT c)
 484 {
 485   return c;
 486 }
 487
 488 tree
 489 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
 490                   bool *ti 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 build_gimple_modify_stmt (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 tree
 524 add_builtin_function (const char *name,
 525                       tree type,
 526                       int function_code,
 527                       enum built_in_class cl,
 528                       const char *library_name,
 529                       tree attrs)
 530 {
 531   tree   id = get_identifier (name);
 532   tree decl = build_decl (FUNCTION_DECL, id, type);
 533
 534   TREE_PUBLIC (decl)         = 1;
 535   DECL_EXTERNAL (decl)       = 1;
 536   DECL_BUILT_IN_CLASS (decl) = cl;
 537   DECL_FUNCTION_CODE (decl)  = function_code;
 538
 539   if (library_name)
 540     {
 541       tree libname = get_identifier (library_name);
 542       SET_DECL_ASSEMBLER_NAME (decl, libname);
 543     }
 544
 545   /* Possibly apply some default attributes to this built-in function.  */
 546   if (attrs)
 547     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 548   else
 549     decl_attributes (&decl, NULL_TREE, 0);
 550
 551   return lang_hooks.builtin_function (decl);
 552
 553 }
 554
 555 tree
 556 lhd_builtin_function (tree decl)
 557 {
 558   lang_hooks.decls.pushdecl (decl);
 559   return decl;
 560 }