gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright 2001, 2002, 2003, 2004 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, 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, 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   if (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
 168          same as that used in the source language.  (That's correct
 169          for C, and GCC used to set DECL_ASSEMBLER_NAME to the same
 170          value as DECL_NAME in build_decl, so this choice provides
 171          backwards compatibility with existing front-ends.
 172
 173          Can't use just the variable's own name for a variable whose
 174          scope is less than the whole compilation.  Concatenate a
 175          distinguishing 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   else
 188     /* Nobody should ever be asking for the DECL_ASSEMBLER_NAME of
 189        these DECLs -- unless they're in language-dependent code, in
 190        which case set_decl_assembler_name hook should handle things.  */
 191     abort ();
 192 }
 193
 194 /* By default we always allow bit-field based optimizations.  */
 195 bool
 196 lhd_can_use_bit_fields_p (void)
 197 {
 198   return true;
 199 }
 200
 201 /* Type promotion for variable arguments.  */
 202 tree
 203 lhd_type_promotes_to (tree ARG_UNUSED (type))
 204 {
 205   abort ();
 206 }
 207
 208 /* Registration of machine- or os-specific builtin types.  */
 209 void
 210 lhd_register_builtin_type (tree ARG_UNUSED (type),
 211                            const char * ARG_UNUSED (name))
 212 {
 213 }
 214
 215 /* Invalid use of an incomplete type.  */
 216 void
 217 lhd_incomplete_type_error (tree ARG_UNUSED (value), tree type)
 218 {
 219   if (TREE_CODE (type) == ERROR_MARK)
 220     return;
 221
 222   abort ();
 223 }
 224
 225 /* Provide a default routine for alias sets that always returns -1.  This
 226    is used by languages that don't need to do anything special.  */
 227
 228 HOST_WIDE_INT
 229 lhd_get_alias_set (tree ARG_UNUSED (t))
 230 {
 231   return -1;
 232 }
 233
 234 /* Provide a hook routine for alias sets that always returns 0.  This is
 235    used by languages that haven't deal with alias sets yet.  */
 236
 237 HOST_WIDE_INT
 238 hook_get_alias_set_0 (tree ARG_UNUSED (t))
 239 {
 240   return 0;
 241 }
 242
 243 /* This is the default expand_expr function.  */
 244
 245 rtx
 246 lhd_expand_expr (tree ARG_UNUSED (t), rtx ARG_UNUSED (r),
 247                  enum machine_mode ARG_UNUSED (mm),
 248                  int ARG_UNUSED (em),
 249                  rtx * ARG_UNUSED (a))
 250 {
 251   abort ();
 252 }
 253
 254 /* The default language-specific function for expanding a decl.  After
 255    the language-independent cases are handled, this function will be
 256    called.  If this function is not defined, it is assumed that
 257    declarations other than those for variables and labels do not require
 258    any RTL generation.  */
 259
 260 int
 261 lhd_expand_decl (tree ARG_UNUSED (t))
 262 {
 263   return 0;
 264 }
 265
 266 /* This is the default decl_printable_name function.  */
 267
 268 const char *
 269 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 270 {
 271   gcc_assert (decl && DECL_NAME (decl));
 272   return IDENTIFIER_POINTER (DECL_NAME (decl));
 273 }
 274
 275 /* This compares two types for equivalence ("compatible" in C-based languages).
 276    This routine should only return 1 if it is sure.  It should not be used
 277    in contexts where erroneously returning 0 causes problems.  */
 278
 279 int
 280 lhd_types_compatible_p (tree x, tree y)
 281 {
 282   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 283 }
 284
 285 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 286    after handling common cases, but before walking code-specific
 287    sub-trees.  If this hook is overridden for a language, it should
 288    handle language-specific tree codes, as well as language-specific
 289    information associated to common tree codes.  If a tree node is
 290    completely handled within this function, it should set *SUBTREES to
 291    0, so that generic handling isn't attempted.  For language-specific
 292    tree codes, generic handling would abort(), so make sure it is set
 293    properly.  Both SUBTREES and *SUBTREES is guaranteed to be nonzero
 294    when the function is called.  */
 295
 296 tree
 297 lhd_tree_inlining_walk_subtrees (tree *tp ATTRIBUTE_UNUSED,
 298                                  int *subtrees ATTRIBUTE_UNUSED,
 299                                  walk_tree_fn func ATTRIBUTE_UNUSED,
 300                                  void *data ATTRIBUTE_UNUSED,
 301                                  struct pointer_set_t *pset ATTRIBUTE_UNUSED)
 302 {
 303   return NULL_TREE;
 304 }
 305
 306 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 307    determine whether there are language-specific reasons for not
 308    inlining a given function.  */
 309
 310 int
 311 lhd_tree_inlining_cannot_inline_tree_fn (tree *fnp)
 312 {
 313   if (flag_really_no_inline
 314       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 315     return 1;
 316
 317   return 0;
 318 }
 319
 320 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 321    determine whether a function should be considered for inlining even
 322    if it would exceed inlining limits.  */
 323
 324 int
 325 lhd_tree_inlining_disregard_inline_limits (tree fn)
 326 {
 327   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 328     return 1;
 329
 330   return 0;
 331 }
 332
 333 /* lang_hooks.tree_inlining.add_pending_fn_decls is called before
 334    starting to inline a function, to push any language-specific
 335    functions that should not be inlined into the current function,
 336    into VAFNP.  PFN is the top of varray, and should be returned if no
 337    functions are pushed into VAFNP.  The top of the varray should be
 338    returned.  */
 339
 340 tree
 341 lhd_tree_inlining_add_pending_fn_decls (void *vafnp ATTRIBUTE_UNUSED, tree pfn)
 342 {
 343   return pfn;
 344 }
 345
 346 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 347    whether VT is an automatic variable defined in function FT.  */
 348
 349 int
 350 lhd_tree_inlining_auto_var_in_fn_p (tree var, tree fn)
 351 {
 352   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 353           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 354                && ! TREE_STATIC (var))
 355               || TREE_CODE (var) == LABEL_DECL
 356               || TREE_CODE (var) == RESULT_DECL));
 357 }
 358
 359 /* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
 360    type node representing an anonymous aggregate (union, struct, etc),
 361    i.e., one whose members are in the same scope as the union itself.  */
 362
 363 int
 364 lhd_tree_inlining_anon_aggr_type_p (tree t ATTRIBUTE_UNUSED)
 365 {
 366   return 0;
 367 }
 368
 369 /* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
 370    language-specific bookkeeping necessary for processing
 371    FN. start_inlining returns nonzero if inlining should proceed, zero if
 372    not.
 373
 374    For instance, the C++ version keeps track of template instantiations to
 375    avoid infinite recursion.  */
 376
 377 int
 378 lhd_tree_inlining_start_inlining (tree fn ATTRIBUTE_UNUSED)
 379 {
 380   return 1;
 381 }
 382
 383 void
 384 lhd_tree_inlining_end_inlining (tree fn ATTRIBUTE_UNUSED)
 385 {
 386 }
 387
 388 /* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
 389    language-specific conversion before assigning VALUE to PARM.  */
 390
 391 tree
 392 lhd_tree_inlining_convert_parm_for_inlining (tree parm ATTRIBUTE_UNUSED,
 393                                              tree value,
 394                                              tree fndecl ATTRIBUTE_UNUSED,
 395                                              int argnum ATTRIBUTE_UNUSED)
 396 {
 397   return value;
 398 }
 399
 400 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 401    nodes.  Returns nonzero if it does not want the usual dumping of the
 402    second argument.  */
 403
 404 bool
 405 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 406 {
 407   return false;
 408 }
 409
 410 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 411    language-specific way.  */
 412
 413 int
 414 lhd_tree_dump_type_quals (tree t)
 415 {
 416   return TYPE_QUALS (t);
 417 }
 418
 419 /* lang_hooks.expr_size: Determine the size of the value of an expression T
 420    in a language-specific way.  Returns a tree for the size in bytes.  */
 421
 422 tree
 423 lhd_expr_size (tree exp)
 424 {
 425   if (DECL_P (exp)
 426       && DECL_SIZE_UNIT (exp) != 0)
 427     return DECL_SIZE_UNIT (exp);
 428   else
 429     return size_in_bytes (TREE_TYPE (exp));
 430 }
 431
 432 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 433
 434 int
 435 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED, tree *pre_p ATTRIBUTE_UNUSED,
 436                    tree *post_p ATTRIBUTE_UNUSED)
 437 {
 438   return GS_UNHANDLED;
 439 }
 440
 441 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 442    which is a language-specific tree code in category tcc_constant or
 443    tcc_exceptional.  The default expects never to be called.  */
 444 size_t
 445 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 446 {
 447   abort ();
 448   return 0;
 449 }
 450
 451 /* Return true if decl, which is a function decl, may be called by a
 452    sibcall.  */
 453
 454 bool
 455 lhd_decl_ok_for_sibcall (tree decl ATTRIBUTE_UNUSED)
 456 {
 457   return true;
 458 }
 459
 460 /* Return the COMDAT group into which DECL should be placed.  */
 461
 462 const char *
 463 lhd_comdat_group (tree decl)
 464 {
 465   return IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
 466 }
 467
 468 /* lang_hooks.decls.final_write_globals: perform final processing on
 469    global variables.  */
 470 void
 471 write_global_declarations (void)
 472 {
 473   /* Really define vars that have had only a tentative definition.
 474      Really output inline functions that must actually be callable
 475      and have not been output so far.  */
 476
 477   tree globals = lang_hooks.decls.getdecls ();
 478   int len = list_length (globals);
 479   tree *vec = xmalloc (sizeof (tree) * len);
 480   int i;
 481   tree decl;
 482
 483   /* Process the decls in reverse order--earliest first.
 484      Put them into VEC from back to front, then take out from front.  */
 485
 486   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
 487     vec[len - i - 1] = decl;
 488
 489   wrapup_global_declarations (vec, len);
 490
 491   check_global_declarations (vec, len);
 492
 493     /* Clean up.  */
 494   free (vec);
 495 }
 496
 497 /* Called to perform language-specific initialization of CTX.  */
 498 void
 499 lhd_initialize_diagnostics (struct diagnostic_context *ctx ATTRIBUTE_UNUSED)
 500 {
 501 }
 502
 503 /* The default function to print out name of current function that caused
 504    an error.  */
 505 void
 506 lhd_print_error_function (diagnostic_context *context, const char *file)
 507 {
 508   if (diagnostic_last_function_changed (context))
 509     {
 510       const char *old_prefix = context->printer->prefix;
 511       char *new_prefix = file ? file_name_as_prefix (file) : NULL;
 512
 513       pp_set_prefix (context->printer, new_prefix);
 514
 515       if (current_function_decl == NULL)
 516         pp_printf (context->printer, _("At top level:"));
 517       else
 518         {
 519           if (TREE_CODE (TREE_TYPE (current_function_decl)) == METHOD_TYPE)
 520             pp_printf
 521               (context->printer, _("In member function %qs:"),
 522                lang_hooks.decl_printable_name (current_function_decl, 2));
 523           else
 524             pp_printf
 525               (context->printer, _("In function %qs:"),
 526                lang_hooks.decl_printable_name (current_function_decl, 2));
 527         }
 528
 529       diagnostic_set_last_function (context);
 530       pp_flush (context->printer);
 531       context->printer->prefix = old_prefix;
 532       free ((char*) new_prefix);
 533     }
 534 }
 535
 536 tree
 537 lhd_callgraph_analyze_expr (tree *tp ATTRIBUTE_UNUSED,
 538                             int *walk_subtrees ATTRIBUTE_UNUSED,
 539                             tree decl ATTRIBUTE_UNUSED)
 540 {
 541   return NULL;
 542 }
 543
 544 tree
 545 lhd_make_node (enum tree_code code)
 546 {
 547   return make_node (code);
 548 }