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 "toplev.h"
  25 #include "tree.h"
  26 #include "c-tree.h"
  27 #include "tree-inline.h"
  28 #include "rtl.h"
  29 #include "insn-config.h"
  30 #include "integrate.h"
  31 #include "flags.h"
  32 #include "langhooks.h"
  33 #include "langhooks-def.h"
  34
  35 /* Do nothing; in many cases the default hook.  */
  36
  37 void
  38 lhd_do_nothing ()
  39 {
  40 }
  41
  42 /* Do nothing (tree).  */
  43
  44 void
  45 lhd_do_nothing_t (t)
  46      tree t ATTRIBUTE_UNUSED;
  47 {
  48 }
  49
  50 /* Do nothing (int).  */
  51
  52 void
  53 lhd_do_nothing_i (i)
  54      int i ATTRIBUTE_UNUSED;
  55 {
  56 }
  57
  58 /* Do nothing (function).  */
  59
  60 void
  61 lhd_do_nothing_f (f)
  62      struct function *f ATTRIBUTE_UNUSED;
  63 {
  64 }
  65
  66 /* Do nothing (return the tree node passed).  */
  67
  68 tree
  69 lhd_return_tree (t)
  70      tree t;
  71 {
  72   return t;
  73 }
  74
  75 /* Do nothing (return NULL_TREE).  */
  76
  77 tree
  78 lhd_return_null_tree (t)
  79      tree t ATTRIBUTE_UNUSED;
  80 {
  81   return NULL_TREE;
  82 }
  83
  84 /* Do nothing; the default hook to decode an option.  */
  85
  86 int
  87 lhd_decode_option (argc, argv)
  88      int argc ATTRIBUTE_UNUSED;
  89      char **argv ATTRIBUTE_UNUSED;
  90 {
  91   return 0;
  92 }
  93
  94 /* Called from by print-tree.c.  */
  95
  96 void
  97 lhd_print_tree_nothing (file, node, indent)
  98      FILE *file ATTRIBUTE_UNUSED;
  99      tree node ATTRIBUTE_UNUSED;
 100      int indent ATTRIBUTE_UNUSED;
 101 {
 102 }
 103
 104 /* Called from safe_from_p.  */
 105
 106 int
 107 lhd_safe_from_p (x, exp)
 108      rtx x ATTRIBUTE_UNUSED;
 109      tree exp ATTRIBUTE_UNUSED;
 110 {
 111   return 1;
 112 }
 113
 114 /* Called from unsafe_for_reeval.  */
 115
 116 int
 117 lhd_unsafe_for_reeval (t)
 118      tree t ATTRIBUTE_UNUSED;
 119 {
 120   return -1;
 121 }
 122
 123 /* Called from staticp.  */
 124
 125 int
 126 lhd_staticp (exp)
 127      tree exp ATTRIBUTE_UNUSED;
 128 {
 129   return 0;
 130 }
 131
 132 /* Called from check_global_declarations.  */
 133
 134 bool
 135 lhd_warn_unused_global_decl (decl)
 136      tree decl;
 137 {
 138   /* This is what used to exist in check_global_declarations.  Probably
 139      not many of these actually apply to non-C languages.  */
 140
 141   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_INLINE (decl))
 142     return false;
 143   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 144     return false;
 145   if (DECL_IN_SYSTEM_HEADER (decl))
 146     return false;
 147
 148   return true;
 149 }
 150
 151 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 152 void
 153 lhd_set_decl_assembler_name (decl)
 154      tree decl;
 155 {
 156   /* The language-independent code should never use the
 157      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 158      VAR_DECLs for variables with static storage duration need a real
 159      DECL_ASSEMBLER_NAME.  */
 160   if (TREE_CODE (decl) == FUNCTION_DECL
 161       || (TREE_CODE (decl) == VAR_DECL
 162           && (TREE_STATIC (decl)
 163               || DECL_EXTERNAL (decl)
 164               || TREE_PUBLIC (decl))))
 165     /* By default, assume the name to use in assembly code is the
 166        same as that used in the source language.  (That's correct
 167        for C, and GCC used to set DECL_ASSEMBLER_NAME to the same
 168        value as DECL_NAME in build_decl, so this choice provides
 169        backwards compatibility with existing front-ends.  */
 170     SET_DECL_ASSEMBLER_NAME (decl, DECL_NAME (decl));
 171   else
 172     /* Nobody should ever be asking for the DECL_ASSEMBLER_NAME of
 173        these DECLs -- unless they're in language-dependent code, in
 174        which case set_decl_assembler_name hook should handle things.  */
 175     abort ();
 176 }
 177
 178 /* By default we always allow bit-field based optimizations.  */
 179 bool
 180 lhd_can_use_bit_fields_p ()
 181 {
 182   return true;
 183 }
 184
 185 /* Provide a default routine to clear the binding stack.  This is used
 186    by languages that don't need to do anything special.  */
 187 void
 188 lhd_clear_binding_stack ()
 189 {
 190   while (! (*lang_hooks.decls.global_bindings_p) ())
 191     poplevel (0, 0, 0);
 192 }
 193
 194 /* Type promotion for variable arguments.  */
 195 tree
 196 lhd_type_promotes_to (type)
 197      tree type ATTRIBUTE_UNUSED;
 198 {
 199   abort ();
 200 }
 201
 202 /* Invalid use of an incomplete type.  */
 203 void
 204 lhd_incomplete_type_error (value, type)
 205      tree value ATTRIBUTE_UNUSED, type;
 206 {
 207   if (TREE_CODE (type) == ERROR_MARK)
 208     return;
 209
 210   abort ();
 211 }
 212
 213 /* Provide a default routine for alias sets that always returns -1.  This
 214    is used by languages that don't need to do anything special.  */
 215
 216 HOST_WIDE_INT
 217 lhd_get_alias_set (t)
 218      tree t ATTRIBUTE_UNUSED;
 219 {
 220   return -1;
 221 }
 222
 223 /* Provide a hook routine for alias sets that always returns 0.  This is
 224    used by languages that haven't deal with alias sets yet.  */
 225
 226 HOST_WIDE_INT
 227 hook_get_alias_set_0 (t)
 228      tree t ATTRIBUTE_UNUSED;
 229 {
 230   return 0;
 231 }
 232
 233 /* This is the default expand_expr function.  */
 234
 235 rtx
 236 lhd_expand_expr (t, r, mm, em)
 237      tree t ATTRIBUTE_UNUSED;
 238      rtx r ATTRIBUTE_UNUSED;
 239      enum machine_mode mm ATTRIBUTE_UNUSED;
 240      int em ATTRIBUTE_UNUSED;
 241 {
 242   abort ();
 243 }
 244
 245 /* This is the default decl_printable_name function.  */
 246
 247 const char *
 248 lhd_decl_printable_name (decl, verbosity)
 249      tree decl;
 250      int verbosity ATTRIBUTE_UNUSED;
 251 {
 252   return IDENTIFIER_POINTER (DECL_NAME (decl));
 253 }
 254
 255 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 256    after handling common cases, but before walking code-specific
 257    sub-trees.  If this hook is overridden for a language, it should
 258    handle language-specific tree codes, as well as language-specific
 259    information associated to common tree codes.  If a tree node is
 260    completely handled within this function, it should set *SUBTREES to
 261    0, so that generic handling isn't attempted.  For language-specific
 262    tree codes, generic handling would abort(), so make sure it is set
 263    properly.  Both SUBTREES and *SUBTREES is guaranteed to be nonzero
 264    when the function is called.  */
 265
 266 tree
 267 lhd_tree_inlining_walk_subtrees (tp,subtrees,func,data,htab)
 268      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 (fnp)
 283      tree *fnp;
 284 {
 285   if (flag_really_no_inline
 286       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 287     return 1;
 288
 289   return 0;
 290 }
 291
 292 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 293    determine whether a function should be considered for inlining even
 294    if it would exceed inlining limits.  */
 295
 296 int
 297 lhd_tree_inlining_disregard_inline_limits (fn)
 298      tree fn;
 299 {
 300   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 301     return 1;
 302
 303   return 0;
 304 }
 305
 306 /* lang_hooks.tree_inlining.add_pending_fn_decls is called before
 307    starting to inline a function, to push any language-specific
 308    functions that should not be inlined into the current function,
 309    into VAFNP.  PFN is the top of varray, and should be returned if no
 310    functions are pushed into VAFNP.  The top of the varray should be
 311    returned.  */
 312
 313 tree
 314 lhd_tree_inlining_add_pending_fn_decls (vafnp, pfn)
 315      void *vafnp ATTRIBUTE_UNUSED;
 316      tree pfn;
 317 {
 318   return pfn;
 319 }
 320
 321 /* lang_hooks.tree_inlining.tree_chain_matters_p indicates whether the
 322    TREE_CHAIN of a language-specific tree node is relevant, i.e.,
 323    whether it should be walked, copied and preserved across copies.  */
 324
 325 int
 326 lhd_tree_inlining_tree_chain_matters_p (t)
 327      tree t ATTRIBUTE_UNUSED;
 328 {
 329   return 0;
 330 }
 331
 332 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 333    whether VT is an automatic variable defined in function FT.  */
 334
 335 int
 336 lhd_tree_inlining_auto_var_in_fn_p (var, fn)
 337      tree var, fn;
 338 {
 339   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 340           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 341                && ! TREE_STATIC (var))
 342               || TREE_CODE (var) == LABEL_DECL
 343               || TREE_CODE (var) == RESULT_DECL));
 344 }
 345
 346 /* lang_hooks.tree_inlining.copy_res_decl_for_inlining should return a
 347    declaration for the result RES of function FN to be inlined into
 348    CALLER.  NDP points to an integer that should be set in case a new
 349    declaration wasn't created (presumably because RES was of aggregate
 350    type, such that a TARGET_EXPR is used for the result).  TEXPS is a
 351    pointer to a varray with the stack of TARGET_EXPRs seen while
 352    inlining functions into caller; the top of TEXPS is supposed to
 353    match RES.  */
 354
 355 tree
 356 lhd_tree_inlining_copy_res_decl_for_inlining (res, fn, caller,
 357                                               dm, ndp, texps)
 358      tree res, fn, caller;
 359      void *dm ATTRIBUTE_UNUSED;
 360      int *ndp ATTRIBUTE_UNUSED;
 361      void *texps ATTRIBUTE_UNUSED;
 362 {
 363   return copy_decl_for_inlining (res, fn, caller);
 364 }
 365
 366 /* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
 367    type node representing an anonymous aggregate (union, struct, etc),
 368    i.e., one whose members are in the same scope as the union itself.  */
 369
 370 int
 371 lhd_tree_inlining_anon_aggr_type_p (t)
 372      tree t ATTRIBUTE_UNUSED;
 373 {
 374   return 0;
 375 }
 376
 377 /* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
 378    language-specific bookkeeping necessary for processing
 379    FN. start_inlining returns nonzero if inlining should proceed, zero if
 380    not.
 381
 382    For instance, the C++ version keeps track of template instantiations to
 383    avoid infinite recursion.  */
 384
 385 int
 386 lhd_tree_inlining_start_inlining (fn)
 387      tree fn ATTRIBUTE_UNUSED;
 388 {
 389   return 1;
 390 }
 391
 392 void
 393 lhd_tree_inlining_end_inlining (fn)
 394      tree fn ATTRIBUTE_UNUSED;
 395 {
 396 }
 397
 398 /* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
 399    language-specific conversion before assigning VALUE to PARM.  */
 400
 401 tree
 402 lhd_tree_inlining_convert_parm_for_inlining (parm, value, fndecl)
 403      tree parm ATTRIBUTE_UNUSED;
 404      tree value;
 405      tree fndecl ATTRIBUTE_UNUSED;
 406 {
 407   return value;
 408 }
 409
 410 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 411    nodes.  Returns nonzero if it does not want the usual dumping of the
 412    second argument.  */
 413
 414 int
 415 lhd_tree_dump_dump_tree (di, t)
 416      void *di ATTRIBUTE_UNUSED;
 417      tree t ATTRIBUTE_UNUSED;
 418 {
 419   return 0;
 420 }
 421
 422 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 423    language-specific way.  */
 424
 425 int
 426 lhd_tree_dump_type_quals (t)
 427      tree t;
 428 {
 429   return TYPE_QUALS (t);
 430 }
 431
 432 /* lang_hooks.expr_size: Determine the size of the value of an expression T
 433    in a language-specific way.  Returns a tree for the size in bytes.  */
 434
 435 tree
 436 lhd_expr_size (exp)
 437      tree exp;
 438 {
 439   if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
 440       && DECL_SIZE_UNIT (exp) != 0)
 441     return DECL_SIZE_UNIT (exp);
 442   else
 443     return size_in_bytes (TREE_TYPE (exp));
 444 }