gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright 2001, 2002, 2003 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 "tm.h"
  26 #include "toplev.h"
  27 #include "tree.h"
  28 #include "tree-inline.h"
  29 #include "rtl.h"
  30 #include "insn-config.h"
  31 #include "integrate.h"
  32 #include "flags.h"
  33 #include "langhooks.h"
  34 #include "langhooks-def.h"
  35 #include "ggc.h"
  36
  37 /* Do nothing; in many cases the default hook.  */
  38
  39 void
  40 lhd_do_nothing (void)
  41 {
  42 }
  43
  44 /* Do nothing (tree).  */
  45
  46 void
  47 lhd_do_nothing_t (tree t ATTRIBUTE_UNUSED)
  48 {
  49 }
  50
  51 /* Do nothing (int).  */
  52
  53 void
  54 lhd_do_nothing_i (int i ATTRIBUTE_UNUSED)
  55 {
  56 }
  57
  58 /* Do nothing (function).  */
  59
  60 void
  61 lhd_do_nothing_f (struct function *f ATTRIBUTE_UNUSED)
  62 {
  63 }
  64
  65 /* Do nothing (return the tree node passed).  */
  66
  67 tree
  68 lhd_return_tree (tree t)
  69 {
  70   return t;
  71 }
  72
  73 /* Do nothing (return NULL_TREE).  */
  74
  75 tree
  76 lhd_return_null_tree (tree t ATTRIBUTE_UNUSED)
  77 {
  78   return NULL_TREE;
  79 }
  80
  81 /* The default post options hook.  */
  82
  83 bool
  84 lhd_post_options (const char **pfilename ATTRIBUTE_UNUSED)
  85 {
  86   return false;
  87 }
  88
  89 /* Called from by print-tree.c.  */
  90
  91 void
  92 lhd_print_tree_nothing (FILE *file ATTRIBUTE_UNUSED,
  93                         tree node ATTRIBUTE_UNUSED,
  94                         int indent ATTRIBUTE_UNUSED)
  95 {
  96 }
  97
  98 /* Called from safe_from_p.  */
  99
 100 int
 101 lhd_safe_from_p (rtx x ATTRIBUTE_UNUSED, tree exp ATTRIBUTE_UNUSED)
 102 {
 103   return 1;
 104 }
 105
 106 /* Called from unsafe_for_reeval.  */
 107
 108 int
 109 lhd_unsafe_for_reeval (tree t ATTRIBUTE_UNUSED)
 110 {
 111   return -1;
 112 }
 113
 114 /* Called from staticp.  */
 115
 116 int
 117 lhd_staticp (tree exp ATTRIBUTE_UNUSED)
 118 {
 119   return 0;
 120 }
 121
 122 /* Called from check_global_declarations.  */
 123
 124 bool
 125 lhd_warn_unused_global_decl (tree decl)
 126 {
 127   /* This is what used to exist in check_global_declarations.  Probably
 128      not many of these actually apply to non-C languages.  */
 129
 130   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_INLINE (decl))
 131     return false;
 132   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 133     return false;
 134   if (DECL_IN_SYSTEM_HEADER (decl))
 135     return false;
 136
 137   return true;
 138 }
 139
 140 /* Number for making the label on the next
 141    static variable internal to a function.  */
 142
 143 static GTY(()) int var_labelno;
 144
 145 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 146 void
 147 lhd_set_decl_assembler_name (tree decl)
 148 {
 149   /* The language-independent code should never use the
 150      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 151      VAR_DECLs for variables with static storage duration need a real
 152      DECL_ASSEMBLER_NAME.  */
 153   if (TREE_CODE (decl) == FUNCTION_DECL
 154       || (TREE_CODE (decl) == VAR_DECL
 155           && (TREE_STATIC (decl)
 156               || DECL_EXTERNAL (decl)
 157               || TREE_PUBLIC (decl))))
 158     {
 159       /* By default, assume the name to use in assembly code is the
 160          same as that used in the source language.  (That's correct
 161          for C, and GCC used to set DECL_ASSEMBLER_NAME to the same
 162          value as DECL_NAME in build_decl, so this choice provides
 163          backwards compatibility with existing front-ends.
 164
 165          Can't use just the variable's own name for a variable whose
 166          scope is less than the whole compilation.  Concatenate a
 167          distinguishing number.  */
 168       if (!TREE_PUBLIC (decl) && DECL_CONTEXT (decl))
 169         {
 170           const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 171           char *label;
 172
 173           ASM_FORMAT_PRIVATE_NAME (label, name, var_labelno);
 174           var_labelno++;
 175           SET_DECL_ASSEMBLER_NAME (decl, get_identifier (label));
 176         }
 177       else
 178         SET_DECL_ASSEMBLER_NAME (decl, DECL_NAME (decl));
 179     }
 180   else
 181     /* Nobody should ever be asking for the DECL_ASSEMBLER_NAME of
 182        these DECLs -- unless they're in language-dependent code, in
 183        which case set_decl_assembler_name hook should handle things.  */
 184     abort ();
 185 }
 186
 187 /* By default we always allow bit-field based optimizations.  */
 188 bool
 189 lhd_can_use_bit_fields_p (void)
 190 {
 191   return true;
 192 }
 193
 194 /* Provide a default routine to clear the binding stack.  This is used
 195    by languages that don't need to do anything special.  */
 196 void
 197 lhd_clear_binding_stack (void)
 198 {
 199   while (! (*lang_hooks.decls.global_bindings_p) ())
 200     poplevel (0, 0, 0);
 201 }
 202
 203 /* Type promotion for variable arguments.  */
 204 tree
 205 lhd_type_promotes_to (tree type ATTRIBUTE_UNUSED)
 206 {
 207   abort ();
 208 }
 209
 210 /* Invalid use of an incomplete type.  */
 211 void
 212 lhd_incomplete_type_error (tree value ATTRIBUTE_UNUSED, tree type)
 213 {
 214   if (TREE_CODE (type) == ERROR_MARK)
 215     return;
 216
 217   abort ();
 218 }
 219
 220 /* Provide a default routine for alias sets that always returns -1.  This
 221    is used by languages that don't need to do anything special.  */
 222
 223 HOST_WIDE_INT
 224 lhd_get_alias_set (tree t ATTRIBUTE_UNUSED)
 225 {
 226   return -1;
 227 }
 228
 229 /* Provide a hook routine for alias sets that always returns 0.  This is
 230    used by languages that haven't deal with alias sets yet.  */
 231
 232 HOST_WIDE_INT
 233 hook_get_alias_set_0 (tree t ATTRIBUTE_UNUSED)
 234 {
 235   return 0;
 236 }
 237
 238 /* This is the default expand_expr function.  */
 239
 240 rtx
 241 lhd_expand_expr (tree t ATTRIBUTE_UNUSED, rtx r ATTRIBUTE_UNUSED,
 242                  enum machine_mode mm ATTRIBUTE_UNUSED,
 243                  int em ATTRIBUTE_UNUSED)
 244 {
 245   abort ();
 246 }
 247
 248 /* This is the default decl_printable_name function.  */
 249
 250 const char *
 251 lhd_decl_printable_name (tree decl, int verbosity ATTRIBUTE_UNUSED)
 252 {
 253   return IDENTIFIER_POINTER (DECL_NAME (decl));
 254 }
 255
 256 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 257    after handling common cases, but before walking code-specific
 258    sub-trees.  If this hook is overridden for a language, it should
 259    handle language-specific tree codes, as well as language-specific
 260    information associated to common tree codes.  If a tree node is
 261    completely handled within this function, it should set *SUBTREES to
 262    0, so that generic handling isn't attempted.  For language-specific
 263    tree codes, generic handling would abort(), so make sure it is set
 264    properly.  Both SUBTREES and *SUBTREES is guaranteed to be nonzero
 265    when the function is called.  */
 266
 267 tree
 268 lhd_tree_inlining_walk_subtrees (tree *tp ATTRIBUTE_UNUSED,
 269                                  int *subtrees ATTRIBUTE_UNUSED,
 270                                  walk_tree_fn func ATTRIBUTE_UNUSED,
 271                                  void *data ATTRIBUTE_UNUSED,
 272                                  void *htab ATTRIBUTE_UNUSED)
 273 {
 274   return NULL_TREE;
 275 }
 276
 277 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 278    determine whether there are language-specific reasons for not
 279    inlining a given function.  */
 280
 281 int
 282 lhd_tree_inlining_cannot_inline_tree_fn (tree *fnp)
 283 {
 284   if (flag_really_no_inline
 285       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 286     return 1;
 287
 288   return 0;
 289 }
 290
 291 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 292    determine whether a function should be considered for inlining even
 293    if it would exceed inlining limits.  */
 294
 295 int
 296 lhd_tree_inlining_disregard_inline_limits (tree fn)
 297 {
 298   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 299     return 1;
 300
 301   return 0;
 302 }
 303
 304 /* lang_hooks.tree_inlining.add_pending_fn_decls is called before
 305    starting to inline a function, to push any language-specific
 306    functions that should not be inlined into the current function,
 307    into VAFNP.  PFN is the top of varray, and should be returned if no
 308    functions are pushed into VAFNP.  The top of the varray should be
 309    returned.  */
 310
 311 tree
 312 lhd_tree_inlining_add_pending_fn_decls (void *vafnp ATTRIBUTE_UNUSED, tree pfn)
 313 {
 314   return pfn;
 315 }
 316
 317 /* lang_hooks.tree_inlining.tree_chain_matters_p indicates whether the
 318    TREE_CHAIN of a language-specific tree node is relevant, i.e.,
 319    whether it should be walked, copied and preserved across copies.  */
 320
 321 int
 322 lhd_tree_inlining_tree_chain_matters_p (tree t ATTRIBUTE_UNUSED)
 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_inlining.copy_res_decl_for_inlining should return a
 341    declaration for the result RES of function FN to be inlined into
 342    CALLER.  NDP points to an integer that should be set in case a new
 343    declaration wasn't created (presumably because RES was of aggregate
 344    type, such that a TARGET_EXPR is used for the result).  TEXPS is a
 345    pointer to a varray with the stack of TARGET_EXPRs seen while
 346    inlining functions into caller; the top of TEXPS is supposed to
 347    match RES.  */
 348
 349 tree
 350 lhd_tree_inlining_copy_res_decl_for_inlining (tree res, tree fn, tree caller,
 351                                               void *dm ATTRIBUTE_UNUSED,
 352                                               int *ndp ATTRIBUTE_UNUSED,
 353                                               tree return_slot_addr ATTRIBUTE_UNUSED)
 354 {
 355   if (return_slot_addr)
 356     return build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (return_slot_addr)),
 357                    return_slot_addr);
 358   else
 359     return copy_decl_for_inlining (res, fn, caller);
 360 }
 361
 362 /* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
 363    type node representing an anonymous aggregate (union, struct, etc),
 364    i.e., one whose members are in the same scope as the union itself.  */
 365
 366 int
 367 lhd_tree_inlining_anon_aggr_type_p (tree t ATTRIBUTE_UNUSED)
 368 {
 369   return 0;
 370 }
 371
 372 /* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
 373    language-specific bookkeeping necessary for processing
 374    FN. start_inlining returns nonzero if inlining should proceed, zero if
 375    not.
 376
 377    For instance, the C++ version keeps track of template instantiations to
 378    avoid infinite recursion.  */
 379
 380 int
 381 lhd_tree_inlining_start_inlining (tree fn ATTRIBUTE_UNUSED)
 382 {
 383   return 1;
 384 }
 385
 386 void
 387 lhd_tree_inlining_end_inlining (tree fn ATTRIBUTE_UNUSED)
 388 {
 389 }
 390
 391 /* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
 392    language-specific conversion before assigning VALUE to PARM.  */
 393
 394 tree
 395 lhd_tree_inlining_convert_parm_for_inlining (tree parm ATTRIBUTE_UNUSED,
 396                                              tree value,
 397                                              tree fndecl ATTRIBUTE_UNUSED)
 398 {
 399   return value;
 400 }
 401
 402 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 403    nodes.  Returns nonzero if it does not want the usual dumping of the
 404    second argument.  */
 405
 406 bool
 407 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 408 {
 409   return false;
 410 }
 411
 412 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 413    language-specific way.  */
 414
 415 int
 416 lhd_tree_dump_type_quals (tree t)
 417 {
 418   return TYPE_QUALS (t);
 419 }
 420
 421 /* lang_hooks.expr_size: Determine the size of the value of an expression T
 422    in a language-specific way.  Returns a tree for the size in bytes.  */
 423
 424 tree
 425 lhd_expr_size (tree exp)
 426 {
 427   if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
 428       && DECL_SIZE_UNIT (exp) != 0)
 429     return DECL_SIZE_UNIT (exp);
 430   else
 431     return size_in_bytes (TREE_TYPE (exp));
 432 }
 433
 434 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 435    which is a language-specific tree code in category 'x'.  The
 436    default expects never to be called.  */
 437 size_t
 438 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 439 {
 440   abort ();
 441   return 0;
 442 }
 443
 444 /* Return true if decl, which is a function decl, may be called by a
 445    sibcall.  */
 446
 447 bool
 448 lhd_decl_ok_for_sibcall (tree decl ATTRIBUTE_UNUSED)
 449 {
 450   return true;
 451 }
 452
 453 /* lang_hooks.decls.final_write_globals: perform final processing on
 454    global variables.  */
 455 void
 456 write_global_declarations (void)
 457 {
 458   /* Really define vars that have had only a tentative definition.
 459      Really output inline functions that must actually be callable
 460      and have not been output so far.  */
 461
 462   tree globals = (*lang_hooks.decls.getdecls) ();
 463   int len = list_length (globals);
 464   tree *vec = xmalloc (sizeof (tree) * len);
 465   int i;
 466   tree decl;
 467
 468   /* Process the decls in reverse order--earliest first.
 469      Put them into VEC from back to front, then take out from front.  */
 470
 471   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
 472     vec[len - i - 1] = decl;
 473
 474   wrapup_global_declarations (vec, len);
 475
 476   check_global_declarations (vec, len);
 477
 478     /* Clean up.  */
 479   free (vec);
 480 }
 481
 482 #include "gt-langhooks.h"