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 /* Called from by print-tree.c.  */
  97
  98 void
  99 lhd_print_tree_nothing (file, node, indent)
 100      FILE *file ATTRIBUTE_UNUSED;
 101      tree node ATTRIBUTE_UNUSED;
 102      int indent ATTRIBUTE_UNUSED;
 103 {
 104 }
 105
 106 /* Called from safe_from_p.  */
 107
 108 int
 109 lhd_safe_from_p (x, exp)
 110      rtx x ATTRIBUTE_UNUSED;
 111      tree exp ATTRIBUTE_UNUSED;
 112 {
 113   return 1;
 114 }
 115
 116 /* Called from unsafe_for_reeval.  */
 117
 118 int
 119 lhd_unsafe_for_reeval (t)
 120      tree t ATTRIBUTE_UNUSED;
 121 {
 122   return -1;
 123 }
 124
 125 /* Called from staticp.  */
 126
 127 int
 128 lhd_staticp (exp)
 129      tree exp ATTRIBUTE_UNUSED;
 130 {
 131   return 0;
 132 }
 133
 134 /* Called from check_global_declarations.  */
 135
 136 bool
 137 lhd_warn_unused_global_decl (decl)
 138      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 (decl)
 156      tree decl;
 157 {
 158   /* The language-independent code should never use the
 159      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 160      VAR_DECLs for variables with static storage duration need a real
 161      DECL_ASSEMBLER_NAME.  */
 162   if (TREE_CODE (decl) == FUNCTION_DECL
 163       || (TREE_CODE (decl) == VAR_DECL
 164           && (TREE_STATIC (decl)
 165               || DECL_EXTERNAL (decl)
 166               || TREE_PUBLIC (decl))))
 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     SET_DECL_ASSEMBLER_NAME (decl, DECL_NAME (decl));
 173   else
 174     /* Nobody should ever be asking for the DECL_ASSEMBLER_NAME of
 175        these DECLs -- unless they're in language-dependent code, in
 176        which case set_decl_assembler_name hook should handle things.  */
 177     abort ();
 178 }
 179
 180 /* By default we always allow bit-field based optimizations.  */
 181 bool
 182 lhd_can_use_bit_fields_p ()
 183 {
 184   return true;
 185 }
 186
 187 /* Provide a default routine to clear the binding stack.  This is used
 188    by languages that don't need to do anything special.  */
 189 void
 190 lhd_clear_binding_stack ()
 191 {
 192   while (! (*lang_hooks.decls.global_bindings_p) ())
 193     poplevel (0, 0, 0);
 194 }
 195
 196 /* Type promotion for variable arguments.  */
 197 tree
 198 lhd_type_promotes_to (type)
 199      tree type ATTRIBUTE_UNUSED;
 200 {
 201   abort ();
 202 }
 203
 204 /* Invalid use of an incomplete type.  */
 205 void
 206 lhd_incomplete_type_error (value, type)
 207      tree value ATTRIBUTE_UNUSED, type;
 208 {
 209   if (TREE_CODE (type) == ERROR_MARK)
 210     return;
 211
 212   abort ();
 213 }
 214
 215 /* Provide a default routine for alias sets that always returns -1.  This
 216    is used by languages that don't need to do anything special.  */
 217
 218 HOST_WIDE_INT
 219 lhd_get_alias_set (t)
 220      tree t ATTRIBUTE_UNUSED;
 221 {
 222   return -1;
 223 }
 224
 225 /* Provide a hook routine for alias sets that always returns 0.  This is
 226    used by languages that haven't deal with alias sets yet.  */
 227
 228 HOST_WIDE_INT
 229 hook_get_alias_set_0 (t)
 230      tree t ATTRIBUTE_UNUSED;
 231 {
 232   return 0;
 233 }
 234
 235 /* This is the default expand_expr function.  */
 236
 237 rtx
 238 lhd_expand_expr (t, r, mm, em)
 239      tree t ATTRIBUTE_UNUSED;
 240      rtx r ATTRIBUTE_UNUSED;
 241      enum machine_mode mm ATTRIBUTE_UNUSED;
 242      int em ATTRIBUTE_UNUSED;
 243 {
 244   abort ();
 245 }
 246
 247 /* This is the default decl_printable_name function.  */
 248
 249 const char *
 250 lhd_decl_printable_name (decl, verbosity)
 251      tree decl;
 252      int verbosity ATTRIBUTE_UNUSED;
 253 {
 254   return IDENTIFIER_POINTER (DECL_NAME (decl));
 255 }
 256
 257 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 258    after handling common cases, but before walking code-specific
 259    sub-trees.  If this hook is overridden for a language, it should
 260    handle language-specific tree codes, as well as language-specific
 261    information associated to common tree codes.  If a tree node is
 262    completely handled within this function, it should set *SUBTREES to
 263    0, so that generic handling isn't attempted.  For language-specific
 264    tree codes, generic handling would abort(), so make sure it is set
 265    properly.  Both SUBTREES and *SUBTREES is guaranteed to be nonzero
 266    when the function is called.  */
 267
 268 tree
 269 lhd_tree_inlining_walk_subtrees (tp,subtrees,func,data,htab)
 270      tree *tp ATTRIBUTE_UNUSED;
 271      int *subtrees ATTRIBUTE_UNUSED;
 272      walk_tree_fn func ATTRIBUTE_UNUSED;
 273      void *data ATTRIBUTE_UNUSED;
 274      void *htab ATTRIBUTE_UNUSED;
 275 {
 276   return NULL_TREE;
 277 }
 278
 279 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 280    determine whether there are language-specific reasons for not
 281    inlining a given function.  */
 282
 283 int
 284 lhd_tree_inlining_cannot_inline_tree_fn (fnp)
 285      tree *fnp;
 286 {
 287   if (flag_really_no_inline
 288       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 289     return 1;
 290
 291   return 0;
 292 }
 293
 294 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 295    determine whether a function should be considered for inlining even
 296    if it would exceed inlining limits.  */
 297
 298 int
 299 lhd_tree_inlining_disregard_inline_limits (fn)
 300      tree fn;
 301 {
 302   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 303     return 1;
 304
 305   return 0;
 306 }
 307
 308 /* lang_hooks.tree_inlining.add_pending_fn_decls is called before
 309    starting to inline a function, to push any language-specific
 310    functions that should not be inlined into the current function,
 311    into VAFNP.  PFN is the top of varray, and should be returned if no
 312    functions are pushed into VAFNP.  The top of the varray should be
 313    returned.  */
 314
 315 tree
 316 lhd_tree_inlining_add_pending_fn_decls (vafnp, pfn)
 317      void *vafnp ATTRIBUTE_UNUSED;
 318      tree pfn;
 319 {
 320   return pfn;
 321 }
 322
 323 /* lang_hooks.tree_inlining.tree_chain_matters_p indicates whether the
 324    TREE_CHAIN of a language-specific tree node is relevant, i.e.,
 325    whether it should be walked, copied and preserved across copies.  */
 326
 327 int
 328 lhd_tree_inlining_tree_chain_matters_p (t)
 329      tree t ATTRIBUTE_UNUSED;
 330 {
 331   return 0;
 332 }
 333
 334 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 335    whether VT is an automatic variable defined in function FT.  */
 336
 337 int
 338 lhd_tree_inlining_auto_var_in_fn_p (var, fn)
 339      tree var, fn;
 340 {
 341   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 342           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 343                && ! TREE_STATIC (var))
 344               || TREE_CODE (var) == LABEL_DECL
 345               || TREE_CODE (var) == RESULT_DECL));
 346 }
 347
 348 /* lang_hooks.tree_inlining.copy_res_decl_for_inlining should return a
 349    declaration for the result RES of function FN to be inlined into
 350    CALLER.  NDP points to an integer that should be set in case a new
 351    declaration wasn't created (presumably because RES was of aggregate
 352    type, such that a TARGET_EXPR is used for the result).  TEXPS is a
 353    pointer to a varray with the stack of TARGET_EXPRs seen while
 354    inlining functions into caller; the top of TEXPS is supposed to
 355    match RES.  */
 356
 357 tree
 358 lhd_tree_inlining_copy_res_decl_for_inlining (res, fn, caller,
 359                                               dm, ndp, return_slot_addr)
 360      tree res, fn, caller;
 361      void *dm ATTRIBUTE_UNUSED;
 362      int *ndp ATTRIBUTE_UNUSED;
 363      tree return_slot_addr ATTRIBUTE_UNUSED;
 364 {
 365   if (return_slot_addr)
 366     return build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (return_slot_addr)),
 367                    return_slot_addr);
 368   else
 369     return copy_decl_for_inlining (res, fn, caller);
 370 }
 371
 372 /* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
 373    type node representing an anonymous aggregate (union, struct, etc),
 374    i.e., one whose members are in the same scope as the union itself.  */
 375
 376 int
 377 lhd_tree_inlining_anon_aggr_type_p (t)
 378      tree t ATTRIBUTE_UNUSED;
 379 {
 380   return 0;
 381 }
 382
 383 /* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
 384    language-specific bookkeeping necessary for processing
 385    FN. start_inlining returns nonzero if inlining should proceed, zero if
 386    not.
 387
 388    For instance, the C++ version keeps track of template instantiations to
 389    avoid infinite recursion.  */
 390
 391 int
 392 lhd_tree_inlining_start_inlining (fn)
 393      tree fn ATTRIBUTE_UNUSED;
 394 {
 395   return 1;
 396 }
 397
 398 void
 399 lhd_tree_inlining_end_inlining (fn)
 400      tree fn ATTRIBUTE_UNUSED;
 401 {
 402 }
 403
 404 /* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
 405    language-specific conversion before assigning VALUE to PARM.  */
 406
 407 tree
 408 lhd_tree_inlining_convert_parm_for_inlining (parm, value, fndecl)
 409      tree parm ATTRIBUTE_UNUSED;
 410      tree value;
 411      tree fndecl ATTRIBUTE_UNUSED;
 412 {
 413   return value;
 414 }
 415
 416 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 417    nodes.  Returns nonzero if it does not want the usual dumping of the
 418    second argument.  */
 419
 420 int
 421 lhd_tree_dump_dump_tree (di, t)
 422      void *di ATTRIBUTE_UNUSED;
 423      tree t ATTRIBUTE_UNUSED;
 424 {
 425   return 0;
 426 }
 427
 428 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 429    language-specific way.  */
 430
 431 int
 432 lhd_tree_dump_type_quals (t)
 433      tree t;
 434 {
 435   return TYPE_QUALS (t);
 436 }
 437
 438 /* lang_hooks.expr_size: Determine the size of the value of an expression T
 439    in a language-specific way.  Returns a tree for the size in bytes.  */
 440
 441 tree
 442 lhd_expr_size (exp)
 443      tree exp;
 444 {
 445   if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
 446       && DECL_SIZE_UNIT (exp) != 0)
 447     return DECL_SIZE_UNIT (exp);
 448   else
 449     return size_in_bytes (TREE_TYPE (exp));
 450 }
 451
 452 /* lang_hooks.decls.final_write_globals: perform final processing on
 453    global variables. */
 454 void
 455 write_global_declarations ()
 456 {
 457   /* Really define vars that have had only a tentative definition.
 458      Really output inline functions that must actually be callable
 459      and have not been output so far.  */
 460
 461   tree globals = (*lang_hooks.decls.getdecls) ();
 462   int len = list_length (globals);
 463   tree *vec = (tree *) xmalloc (sizeof (tree) * len);
 464   int i;
 465   tree decl;
 466
 467   /* Process the decls in reverse order--earliest first.
 468      Put them into VEC from back to front, then take out from front.  */
 469
 470   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
 471     vec[len - i - 1] = decl;
 472
 473   wrapup_global_declarations (vec, len);
 474
 475   check_global_declarations (vec, len);
 476
 477     /* Clean up.  */
 478   free (vec);
 479 }