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 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 "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 "target.h"
  37 #include "langhooks-def.h"
  38 #include "ggc.h"
  39 #include "diagnostic.h"
  40
  41 /* Do nothing; in many cases the default hook.  */
  42
  43 void
  44 lhd_do_nothing (void)
  45 {
  46 }
  47
  48 /* Do nothing (tree).  */
  49
  50 void
  51 lhd_do_nothing_t (tree ARG_UNUSED (t))
  52 {
  53 }
  54
  55 /* Do nothing (int).  */
  56
  57 void
  58 lhd_do_nothing_i (int ARG_UNUSED (i))
  59 {
  60 }
  61
  62 /* Do nothing (int, int, int).  Return NULL_TREE.  */
  63
  64 tree
  65 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  66                                      int ARG_UNUSED (j),
  67                                      int ARG_UNUSED (k))
  68 {
  69   return NULL_TREE;
  70 }
  71
  72 /* Do nothing (function).  */
  73
  74 void
  75 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  76 {
  77 }
  78
  79 /* Do nothing (return the tree node passed).  */
  80
  81 tree
  82 lhd_return_tree (tree t)
  83 {
  84   return t;
  85 }
  86
  87 /* Do nothing (return NULL_TREE).  */
  88
  89 tree
  90 lhd_return_null_tree_v (void)
  91 {
  92   return NULL_TREE;
  93 }
  94
  95 /* Do nothing (return NULL_TREE).  */
  96
  97 tree
  98 lhd_return_null_tree (tree ARG_UNUSED (t))
  99 {
 100   return NULL_TREE;
 101 }
 102
 103 /* Do nothing (return NULL_TREE).  */
 104
 105 tree
 106 lhd_return_null_const_tree (const_tree ARG_UNUSED (t))
 107 {
 108   return NULL_TREE;
 109 }
 110
 111 /* The default post options hook.  */
 112
 113 bool
 114 lhd_post_options (const char ** ARG_UNUSED (pfilename))
 115 {
 116   return false;
 117 }
 118
 119 /* Called from by print-tree.c.  */
 120
 121 void
 122 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 123                         tree ARG_UNUSED (node),
 124                         int ARG_UNUSED (indent))
 125 {
 126 }
 127
 128 /* Called from staticp.  */
 129
 130 tree
 131 lhd_staticp (tree ARG_UNUSED (exp))
 132 {
 133   return NULL;
 134 }
 135
 136 /* Called from check_global_declarations.  */
 137
 138 bool
 139 lhd_warn_unused_global_decl (tree decl)
 140 {
 141   /* This is what used to exist in check_global_declarations.  Probably
 142      not many of these actually apply to non-C languages.  */
 143
 144   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_INLINE (decl))
 145     return false;
 146   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 147     return false;
 148   if (DECL_IN_SYSTEM_HEADER (decl))
 149     return false;
 150
 151   return true;
 152 }
 153
 154 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 155 void
 156 lhd_set_decl_assembler_name (tree decl)
 157 {
 158   tree id;
 159
 160   /* The language-independent code should never use the
 161      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 162      VAR_DECLs for variables with static storage duration need a real
 163      DECL_ASSEMBLER_NAME.  */
 164   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 165               || (TREE_CODE (decl) == VAR_DECL
 166                   && (TREE_STATIC (decl)
 167                       || DECL_EXTERNAL (decl)
 168                       || TREE_PUBLIC (decl))));
 169
 170   /* By default, assume the name to use in assembly code is the same
 171      as that used in the source language.  (That's correct for C, and
 172      GCC used to set DECL_ASSEMBLER_NAME to the same value as
 173      DECL_NAME in build_decl, so this choice provides backwards
 174      compatibility with existing front-ends.  This assumption is wrapped
 175      in a target hook, to allow for target-specific modification of the
 176      identifier.
 177
 178      Can't use just the variable's own name for a variable whose scope
 179      is less than the whole compilation.  Concatenate a distinguishing
 180      number - we use the DECL_UID.  */
 181
 182   if (TREE_PUBLIC (decl) || DECL_CONTEXT (decl) == NULL_TREE)
 183     id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
 184   else
 185     {
 186       const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 187       char *label;
 188
 189       ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 190       id = get_identifier (label);
 191     }
 192   SET_DECL_ASSEMBLER_NAME (decl, id);
 193
 194 }
 195
 196 /* Type promotion for variable arguments.  */
 197 tree
 198 lhd_type_promotes_to (tree ARG_UNUSED (type))
 199 {
 200   gcc_unreachable ();
 201 }
 202
 203 /* Registration of machine- or os-specific builtin types.  */
 204 void
 205 lhd_register_builtin_type (tree ARG_UNUSED (type),
 206                            const char * ARG_UNUSED (name))
 207 {
 208 }
 209
 210 /* Invalid use of an incomplete type.  */
 211 void
 212 lhd_incomplete_type_error (tree ARG_UNUSED (value), tree type)
 213 {
 214   gcc_assert (TREE_CODE (type) == ERROR_MARK);
 215   return;
 216 }
 217
 218 /* Provide a default routine for alias sets that always returns -1.  This
 219    is used by languages that don't need to do anything special.  */
 220
 221 alias_set_type
 222 lhd_get_alias_set (tree ARG_UNUSED (t))
 223 {
 224   return -1;
 225 }
 226
 227 /* This is the default expand_expr function.  */
 228
 229 rtx
 230 lhd_expand_expr (tree ARG_UNUSED (t), rtx ARG_UNUSED (r),
 231                  enum machine_mode ARG_UNUSED (mm),
 232                  int ARG_UNUSED (em),
 233                  rtx * ARG_UNUSED (a))
 234 {
 235   gcc_unreachable ();
 236 }
 237
 238 /* The default language-specific function for expanding a decl.  After
 239    the language-independent cases are handled, this function will be
 240    called.  If this function is not defined, it is assumed that
 241    declarations other than those for variables and labels do not require
 242    any RTL generation.  */
 243
 244 int
 245 lhd_expand_decl (tree ARG_UNUSED (t))
 246 {
 247   return 0;
 248 }
 249
 250 /* This is the default decl_printable_name function.  */
 251
 252 const char *
 253 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 254 {
 255   gcc_assert (decl && DECL_NAME (decl));
 256   return IDENTIFIER_POINTER (DECL_NAME (decl));
 257 }
 258
 259 /* This is the default dwarf_name function.  */
 260
 261 const char *
 262 lhd_dwarf_name (tree t, int verbosity)
 263 {
 264   gcc_assert (DECL_P (t));
 265
 266   return lang_hooks.decl_printable_name (t, verbosity);
 267 }
 268
 269 /* This compares two types for equivalence ("compatible" in C-based languages).
 270    This routine should only return 1 if it is sure.  It should not be used
 271    in contexts where erroneously returning 0 causes problems.  */
 272
 273 int
 274 lhd_types_compatible_p (tree x, tree y)
 275 {
 276   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 277 }
 278
 279 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 280    after handling common cases, but before walking code-specific
 281    sub-trees.  If this hook is overridden for a language, it should
 282    handle language-specific tree codes, as well as language-specific
 283    information associated to common tree codes.  If a tree node is
 284    completely handled within this function, it should set *SUBTREES to
 285    0, so that generic handling isn't attempted.  The generic handling
 286    cannot deal with language-specific tree codes, so make sure it is
 287    set properly.  Both SUBTREES and *SUBTREES is guaranteed to be
 288    nonzero when the function is called.  */
 289
 290 tree
 291 lhd_tree_inlining_walk_subtrees (tree *tp ATTRIBUTE_UNUSED,
 292                                  int *subtrees ATTRIBUTE_UNUSED,
 293                                  walk_tree_fn func ATTRIBUTE_UNUSED,
 294                                  void *data ATTRIBUTE_UNUSED,
 295                                  struct pointer_set_t *pset ATTRIBUTE_UNUSED)
 296 {
 297   return NULL_TREE;
 298 }
 299
 300 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 301    determine whether there are language-specific reasons for not
 302    inlining a given function.  */
 303
 304 int
 305 lhd_tree_inlining_cannot_inline_tree_fn (tree *fnp)
 306 {
 307   if (flag_really_no_inline
 308       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 309     return 1;
 310
 311   return 0;
 312 }
 313
 314 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 315    determine whether a function should be considered for inlining even
 316    if it would exceed inlining limits.  */
 317
 318 int
 319 lhd_tree_inlining_disregard_inline_limits (tree fn)
 320 {
 321   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 322     return 1;
 323
 324   return 0;
 325 }
 326
 327 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 328    whether VT is an automatic variable defined in function FT.  */
 329
 330 int
 331 lhd_tree_inlining_auto_var_in_fn_p (tree var, tree fn)
 332 {
 333   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 334           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 335                && ! TREE_STATIC (var))
 336               || TREE_CODE (var) == LABEL_DECL
 337               || TREE_CODE (var) == RESULT_DECL));
 338 }
 339
 340 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 341    nodes.  Returns nonzero if it does not want the usual dumping of the
 342    second argument.  */
 343
 344 bool
 345 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 346 {
 347   return false;
 348 }
 349
 350 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 351    language-specific way.  */
 352
 353 int
 354 lhd_tree_dump_type_quals (tree t)
 355 {
 356   return TYPE_QUALS (t);
 357 }
 358
 359 /* lang_hooks.expr_size: Determine the size of the value of an expression T
 360    in a language-specific way.  Returns a tree for the size in bytes.  */
 361
 362 tree
 363 lhd_expr_size (tree exp)
 364 {
 365   if (DECL_P (exp)
 366       && DECL_SIZE_UNIT (exp) != 0)
 367     return DECL_SIZE_UNIT (exp);
 368   else
 369     return size_in_bytes (TREE_TYPE (exp));
 370 }
 371
 372 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 373
 374 int
 375 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED, tree *pre_p ATTRIBUTE_UNUSED,
 376                    tree *post_p ATTRIBUTE_UNUSED)
 377 {
 378   return GS_UNHANDLED;
 379 }
 380
 381 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 382    which is a language-specific tree code in category tcc_constant or
 383    tcc_exceptional.  The default expects never to be called.  */
 384 size_t
 385 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 386 {
 387   gcc_unreachable ();
 388 }
 389
 390 /* Return true if decl, which is a function decl, may be called by a
 391    sibcall.  */
 392
 393 bool
 394 lhd_decl_ok_for_sibcall (tree decl ATTRIBUTE_UNUSED)
 395 {
 396   return true;
 397 }
 398
 399 /* Return the COMDAT group into which DECL should be placed.  */
 400
 401 const char *
 402 lhd_comdat_group (tree decl)
 403 {
 404   return IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
 405 }
 406
 407 /* lang_hooks.decls.final_write_globals: perform final processing on
 408    global variables.  */
 409 void
 410 write_global_declarations (void)
 411 {
 412   /* Really define vars that have had only a tentative definition.
 413      Really output inline functions that must actually be callable
 414      and have not been output so far.  */
 415
 416   tree globals = lang_hooks.decls.getdecls ();
 417   int len = list_length (globals);
 418   tree *vec = XNEWVEC (tree, len);
 419   int i;
 420   tree decl;
 421
 422   /* Process the decls in reverse order--earliest first.
 423      Put them into VEC from back to front, then take out from front.  */
 424
 425   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
 426     vec[len - i - 1] = decl;
 427
 428   wrapup_global_declarations (vec, len);
 429   check_global_declarations (vec, len);
 430   emit_debug_global_declarations (vec, len);
 431
 432   /* Clean up.  */
 433   free (vec);
 434 }
 435
 436 /* Called to perform language-specific initialization of CTX.  */
 437 void
 438 lhd_initialize_diagnostics (struct diagnostic_context *ctx ATTRIBUTE_UNUSED)
 439 {
 440 }
 441
 442 /* The default function to print out name of current function that caused
 443    an error.  */
 444 void
 445 lhd_print_error_function (diagnostic_context *context, const char *file)
 446 {
 447   if (diagnostic_last_function_changed (context))
 448     {
 449       const char *old_prefix = context->printer->prefix;
 450       char *new_prefix = file ? file_name_as_prefix (file) : NULL;
 451
 452       pp_set_prefix (context->printer, new_prefix);
 453
 454       if (current_function_decl == NULL)
 455         pp_printf (context->printer, _("At top level:"));
 456       else
 457         {
 458           if (TREE_CODE (TREE_TYPE (current_function_decl)) == METHOD_TYPE)
 459             pp_printf
 460               (context->printer, _("In member function %qs:"),
 461                lang_hooks.decl_printable_name (current_function_decl, 2));
 462           else
 463             pp_printf
 464               (context->printer, _("In function %qs:"),
 465                lang_hooks.decl_printable_name (current_function_decl, 2));
 466         }
 467
 468       diagnostic_set_last_function (context);
 469       pp_flush (context->printer);
 470       context->printer->prefix = old_prefix;
 471       free ((char*) new_prefix);
 472     }
 473 }
 474
 475 tree
 476 lhd_callgraph_analyze_expr (tree *tp ATTRIBUTE_UNUSED,
 477                             int *walk_subtrees ATTRIBUTE_UNUSED,
 478                             tree decl ATTRIBUTE_UNUSED)
 479 {
 480   return NULL;
 481 }
 482
 483 tree
 484 lhd_make_node (enum tree_code code)
 485 {
 486   return make_node (code);
 487 }
 488
 489 HOST_WIDE_INT
 490 lhd_to_target_charset (HOST_WIDE_INT c)
 491 {
 492   return c;
 493 }
 494
 495 tree
 496 lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
 497                   bool *ti ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSED)
 498 {
 499   return expr;
 500 }
 501
 502 /* Return sharing kind if OpenMP sharing attribute of DECL is
 503    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 504
 505 enum omp_clause_default_kind
 506 lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
 507 {
 508   if (DECL_ARTIFICIAL (decl))
 509     return OMP_CLAUSE_DEFAULT_SHARED;
 510   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 511 }
 512
 513 /* Generate code to copy SRC to DST.  */
 514
 515 tree
 516 lhd_omp_assignment (tree clause ATTRIBUTE_UNUSED, tree dst, tree src)
 517 {
 518   return build_gimple_modify_stmt (dst, src);
 519 }
 520
 521 /* Register language specific type size variables as potentially OpenMP
 522    firstprivate variables.  */
 523
 524 void
 525 lhd_omp_firstprivatize_type_sizes (struct gimplify_omp_ctx *c ATTRIBUTE_UNUSED,
 526                                    tree t ATTRIBUTE_UNUSED)
 527 {
 528 }
 529
 530 tree
 531 add_builtin_function (const char *name,
 532                       tree type,
 533                       int function_code,
 534                       enum built_in_class cl,
 535                       const char *library_name,
 536                       tree attrs)
 537 {
 538   tree   id = get_identifier (name);
 539   tree decl = build_decl (FUNCTION_DECL, id, type);
 540
 541   TREE_PUBLIC (decl)         = 1;
 542   DECL_EXTERNAL (decl)       = 1;
 543   DECL_BUILT_IN_CLASS (decl) = cl;
 544   DECL_FUNCTION_CODE (decl)  = function_code;
 545
 546   if (library_name)
 547     {
 548       tree libname = get_identifier (library_name);
 549       SET_DECL_ASSEMBLER_NAME (decl, libname);
 550     }
 551
 552   /* Possibly apply some default attributes to this built-in function.  */
 553   if (attrs)
 554     decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
 555   else
 556     decl_attributes (&decl, NULL_TREE, 0);
 557
 558   return lang_hooks.builtin_function (decl);
 559
 560 }
 561
 562 tree
 563 lhd_builtin_function (tree decl)
 564 {
 565   lang_hooks.decls.pushdecl (decl);
 566   return decl;
 567 }