gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright 2001, 2002 Free Software Foundation, Inc.
   3    Contributed by Alexandre Oliva  <aoliva@redhat.com>
   4
   5 This file is part of GNU CC.
   6
   7 GNU CC 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 GNU CC 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 GNU CC; 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 "c-tree.h"
  29 #include "tree-inline.h"
  30 #include "rtl.h"
  31 #include "insn-config.h"
  32 #include "integrate.h"
  33 #include "flags.h"
  34 #include "langhooks.h"
  35 #include "langhooks-def.h"
  36
  37 /* Do nothing; in many cases the default hook.  */
  38
  39 void
  40 lhd_do_nothing ()
  41 {
  42 }
  43
  44 /* Do nothing (tree).  */
  45
  46 void
  47 lhd_do_nothing_t (t)
  48      tree t ATTRIBUTE_UNUSED;
  49 {
  50 }
  51
  52 /* Do nothing (int).  */
  53
  54 void
  55 lhd_do_nothing_i (i)
  56      int i ATTRIBUTE_UNUSED;
  57 {
  58 }
  59
  60 /* Do nothing (function).  */
  61
  62 void
  63 lhd_do_nothing_f (f)
  64      struct function *f ATTRIBUTE_UNUSED;
  65 {
  66 }
  67
  68 /* Do nothing (return the tree node passed).  */
  69
  70 tree
  71 lhd_return_tree (t)
  72      tree t;
  73 {
  74   return t;
  75 }
  76
  77 /* Do nothing (return NULL_TREE).  */
  78
  79 tree
  80 lhd_return_null_tree (t)
  81      tree t ATTRIBUTE_UNUSED;
  82 {
  83   return NULL_TREE;
  84 }
  85
  86 /* Do nothing; the default hook to decode an option.  */
  87
  88 int
  89 lhd_decode_option (argc, argv)
  90      int argc ATTRIBUTE_UNUSED;
  91      char **argv ATTRIBUTE_UNUSED;
  92 {
  93   return 0;
  94 }
  95
  96 /* The default post options hook.  */
  97
  98 bool
  99 lhd_post_options (pfilename)
 100      const char **pfilename ATTRIBUTE_UNUSED;
 101 {
 102   return false;
 103 }
 104
 105 /* Called from by print-tree.c.  */
 106
 107 void
 108 lhd_print_tree_nothing (file, node, indent)
 109      FILE *file ATTRIBUTE_UNUSED;
 110      tree node ATTRIBUTE_UNUSED;
 111      int indent ATTRIBUTE_UNUSED;
 112 {
 113 }
 114
 115 /* Called from safe_from_p.  */
 116
 117 int
 118 lhd_safe_from_p (x, exp)
 119      rtx x ATTRIBUTE_UNUSED;
 120      tree exp ATTRIBUTE_UNUSED;
 121 {
 122   return 1;
 123 }
 124
 125 /* Called from unsafe_for_reeval.  */
 126
 127 int
 128 lhd_unsafe_for_reeval (t)
 129      tree t ATTRIBUTE_UNUSED;
 130 {
 131   return -1;
 132 }
 133
 134 /* Called from staticp.  */
 135
 136 int
 137 lhd_staticp (exp)
 138      tree exp ATTRIBUTE_UNUSED;
 139 {
 140   return 0;
 141 }
 142
 143 /* Called from check_global_declarations.  */
 144
 145 bool
 146 lhd_warn_unused_global_decl (decl)
 147      tree decl;
 148 {
 149   /* This is what used to exist in check_global_declarations.  Probably
 150      not many of these actually apply to non-C languages.  */
 151
 152   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_INLINE (decl))
 153     return false;
 154   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 155     return false;
 156   if (DECL_IN_SYSTEM_HEADER (decl))
 157     return false;
 158
 159   return true;
 160 }
 161
 162 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 163 void
 164 lhd_set_decl_assembler_name (decl)
 165      tree decl;
 166 {
 167   /* The language-independent code should never use the
 168      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 169      VAR_DECLs for variables with static storage duration need a real
 170      DECL_ASSEMBLER_NAME.  */
 171   if (TREE_CODE (decl) == FUNCTION_DECL
 172       || (TREE_CODE (decl) == VAR_DECL
 173           && (TREE_STATIC (decl)
 174               || DECL_EXTERNAL (decl)
 175               || TREE_PUBLIC (decl))))
 176     /* By default, assume the name to use in assembly code is the
 177        same as that used in the source language.  (That's correct
 178        for C, and GCC used to set DECL_ASSEMBLER_NAME to the same
 179        value as DECL_NAME in build_decl, so this choice provides
 180        backwards compatibility with existing front-ends.  */
 181     SET_DECL_ASSEMBLER_NAME (decl, DECL_NAME (decl));
 182   else
 183     /* Nobody should ever be asking for the DECL_ASSEMBLER_NAME of
 184        these DECLs -- unless they're in language-dependent code, in
 185        which case set_decl_assembler_name hook should handle things.  */
 186     abort ();
 187 }
 188
 189 /* By default we always allow bit-field based optimizations.  */
 190 bool
 191 lhd_can_use_bit_fields_p ()
 192 {
 193   return true;
 194 }
 195
 196 /* Provide a default routine to clear the binding stack.  This is used
 197    by languages that don't need to do anything special.  */
 198 void
 199 lhd_clear_binding_stack ()
 200 {
 201   while (! (*lang_hooks.decls.global_bindings_p) ())
 202     poplevel (0, 0, 0);
 203 }
 204
 205 /* Type promotion for variable arguments.  */
 206 tree
 207 lhd_type_promotes_to (type)
 208      tree type ATTRIBUTE_UNUSED;
 209 {
 210   abort ();
 211 }
 212
 213 /* Invalid use of an incomplete type.  */
 214 void
 215 lhd_incomplete_type_error (value, type)
 216      tree value ATTRIBUTE_UNUSED, type;
 217 {
 218   if (TREE_CODE (type) == ERROR_MARK)
 219     return;
 220
 221   abort ();
 222 }
 223
 224 /* Provide a default routine for alias sets that always returns -1.  This
 225    is used by languages that don't need to do anything special.  */
 226
 227 HOST_WIDE_INT
 228 lhd_get_alias_set (t)
 229      tree t ATTRIBUTE_UNUSED;
 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 (t)
 239      tree t ATTRIBUTE_UNUSED;
 240 {
 241   return 0;
 242 }
 243
 244 /* This is the default expand_expr function.  */
 245
 246 rtx
 247 lhd_expand_expr (t, r, mm, em)
 248      tree t ATTRIBUTE_UNUSED;
 249      rtx r ATTRIBUTE_UNUSED;
 250      enum machine_mode mm ATTRIBUTE_UNUSED;
 251      int em ATTRIBUTE_UNUSED;
 252 {
 253   abort ();
 254 }
 255
 256 /* This is the default decl_printable_name function.  */
 257
 258 const char *
 259 lhd_decl_printable_name (decl, verbosity)
 260      tree decl;
 261      int verbosity ATTRIBUTE_UNUSED;
 262 {
 263   return IDENTIFIER_POINTER (DECL_NAME (decl));
 264 }
 265
 266 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 267    after handling common cases, but before walking code-specific
 268    sub-trees.  If this hook is overridden for a language, it should
 269    handle language-specific tree codes, as well as language-specific
 270    information associated to common tree codes.  If a tree node is
 271    completely handled within this function, it should set *SUBTREES to
 272    0, so that generic handling isn't attempted.  For language-specific
 273    tree codes, generic handling would abort(), so make sure it is set
 274    properly.  Both SUBTREES and *SUBTREES is guaranteed to be nonzero
 275    when the function is called.  */
 276
 277 tree
 278 lhd_tree_inlining_walk_subtrees (tp,subtrees,func,data,htab)
 279      tree *tp ATTRIBUTE_UNUSED;
 280      int *subtrees ATTRIBUTE_UNUSED;
 281      walk_tree_fn func ATTRIBUTE_UNUSED;
 282      void *data ATTRIBUTE_UNUSED;
 283      void *htab ATTRIBUTE_UNUSED;
 284 {
 285   return NULL_TREE;
 286 }
 287
 288 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 289    determine whether there are language-specific reasons for not
 290    inlining a given function.  */
 291
 292 int
 293 lhd_tree_inlining_cannot_inline_tree_fn (fnp)
 294      tree *fnp;
 295 {
 296   if (flag_really_no_inline
 297       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 298     return 1;
 299
 300   return 0;
 301 }
 302
 303 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 304    determine whether a function should be considered for inlining even
 305    if it would exceed inlining limits.  */
 306
 307 int
 308 lhd_tree_inlining_disregard_inline_limits (fn)
 309      tree fn;
 310 {
 311   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 312     return 1;
 313
 314   return 0;
 315 }
 316
 317 /* lang_hooks.tree_inlining.add_pending_fn_decls is called before
 318    starting to inline a function, to push any language-specific
 319    functions that should not be inlined into the current function,
 320    into VAFNP.  PFN is the top of varray, and should be returned if no
 321    functions are pushed into VAFNP.  The top of the varray should be
 322    returned.  */
 323
 324 tree
 325 lhd_tree_inlining_add_pending_fn_decls (vafnp, pfn)
 326      void *vafnp ATTRIBUTE_UNUSED;
 327      tree pfn;
 328 {
 329   return pfn;
 330 }
 331
 332 /* lang_hooks.tree_inlining.tree_chain_matters_p indicates whether the
 333    TREE_CHAIN of a language-specific tree node is relevant, i.e.,
 334    whether it should be walked, copied and preserved across copies.  */
 335
 336 int
 337 lhd_tree_inlining_tree_chain_matters_p (t)
 338      tree t ATTRIBUTE_UNUSED;
 339 {
 340   return 0;
 341 }
 342
 343 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 344    whether VT is an automatic variable defined in function FT.  */
 345
 346 int
 347 lhd_tree_inlining_auto_var_in_fn_p (var, fn)
 348      tree var, fn;
 349 {
 350   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 351           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 352                && ! TREE_STATIC (var))
 353               || TREE_CODE (var) == LABEL_DECL
 354               || TREE_CODE (var) == RESULT_DECL));
 355 }
 356
 357 /* lang_hooks.tree_inlining.copy_res_decl_for_inlining should return a
 358    declaration for the result RES of function FN to be inlined into
 359    CALLER.  NDP points to an integer that should be set in case a new
 360    declaration wasn't created (presumably because RES was of aggregate
 361    type, such that a TARGET_EXPR is used for the result).  TEXPS is a
 362    pointer to a varray with the stack of TARGET_EXPRs seen while
 363    inlining functions into caller; the top of TEXPS is supposed to
 364    match RES.  */
 365
 366 tree
 367 lhd_tree_inlining_copy_res_decl_for_inlining (res, fn, caller,
 368                                               dm, ndp, return_slot_addr)
 369      tree res, fn, caller;
 370      void *dm ATTRIBUTE_UNUSED;
 371      int *ndp ATTRIBUTE_UNUSED;
 372      tree return_slot_addr ATTRIBUTE_UNUSED;
 373 {
 374   if (return_slot_addr)
 375     return build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (return_slot_addr)),
 376                    return_slot_addr);
 377   else
 378     return copy_decl_for_inlining (res, fn, caller);
 379 }
 380
 381 /* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
 382    type node representing an anonymous aggregate (union, struct, etc),
 383    i.e., one whose members are in the same scope as the union itself.  */
 384
 385 int
 386 lhd_tree_inlining_anon_aggr_type_p (t)
 387      tree t ATTRIBUTE_UNUSED;
 388 {
 389   return 0;
 390 }
 391
 392 /* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
 393    language-specific bookkeeping necessary for processing
 394    FN. start_inlining returns nonzero if inlining should proceed, zero if
 395    not.
 396
 397    For instance, the C++ version keeps track of template instantiations to
 398    avoid infinite recursion.  */
 399
 400 int
 401 lhd_tree_inlining_start_inlining (fn)
 402      tree fn ATTRIBUTE_UNUSED;
 403 {
 404   return 1;
 405 }
 406
 407 void
 408 lhd_tree_inlining_end_inlining (fn)
 409      tree fn ATTRIBUTE_UNUSED;
 410 {
 411 }
 412
 413 /* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
 414    language-specific conversion before assigning VALUE to PARM.  */
 415
 416 tree
 417 lhd_tree_inlining_convert_parm_for_inlining (parm, value, fndecl)
 418      tree parm ATTRIBUTE_UNUSED;
 419      tree value;
 420      tree fndecl ATTRIBUTE_UNUSED;
 421 {
 422   return value;
 423 }
 424
 425 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 426    nodes.  Returns nonzero if it does not want the usual dumping of the
 427    second argument.  */
 428
 429 int
 430 lhd_tree_dump_dump_tree (di, t)
 431      void *di ATTRIBUTE_UNUSED;
 432      tree t ATTRIBUTE_UNUSED;
 433 {
 434   return 0;
 435 }
 436
 437 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 438    language-specific way.  */
 439
 440 int
 441 lhd_tree_dump_type_quals (t)
 442      tree t;
 443 {
 444   return TYPE_QUALS (t);
 445 }
 446
 447 /* lang_hooks.expr_size: Determine the size of the value of an expression T
 448    in a language-specific way.  Returns a tree for the size in bytes.  */
 449
 450 tree
 451 lhd_expr_size (exp)
 452      tree exp;
 453 {
 454   if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
 455       && DECL_SIZE_UNIT (exp) != 0)
 456     return DECL_SIZE_UNIT (exp);
 457   else
 458     return size_in_bytes (TREE_TYPE (exp));
 459 }
 460
 461 /* lang_hooks.decls.final_write_globals: perform final processing on
 462    global variables.  */
 463 void
 464 write_global_declarations ()
 465 {
 466   /* Really define vars that have had only a tentative definition.
 467      Really output inline functions that must actually be callable
 468      and have not been output so far.  */
 469
 470   tree globals = (*lang_hooks.decls.getdecls) ();
 471   int len = list_length (globals);
 472   tree *vec = (tree *) xmalloc (sizeof (tree) * len);
 473   int i;
 474   tree decl;
 475
 476   /* Process the decls in reverse order--earliest first.
 477      Put them into VEC from back to front, then take out from front.  */
 478
 479   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
 480     vec[len - i - 1] = decl;
 481
 482   wrapup_global_declarations (vec, len);
 483
 484   check_global_declarations (vec, len);
 485
 486     /* Clean up.  */
 487   free (vec);
 488 }