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
  36 /* Do nothing; in many cases the default hook.  */
  37
  38 void
  39 lhd_do_nothing (void)
  40 {
  41 }
  42
  43 /* Do nothing (tree).  */
  44
  45 void
  46 lhd_do_nothing_t (tree t ATTRIBUTE_UNUSED)
  47 {
  48 }
  49
  50 /* Do nothing (int).  */
  51
  52 void
  53 lhd_do_nothing_i (int i ATTRIBUTE_UNUSED)
  54 {
  55 }
  56
  57 /* Do nothing (function).  */
  58
  59 void
  60 lhd_do_nothing_f (struct function *f ATTRIBUTE_UNUSED)
  61 {
  62 }
  63
  64 /* Do nothing (return the tree node passed).  */
  65
  66 tree
  67 lhd_return_tree (tree t)
  68 {
  69   return t;
  70 }
  71
  72 /* Do nothing (return NULL_TREE).  */
  73
  74 tree
  75 lhd_return_null_tree (tree t ATTRIBUTE_UNUSED)
  76 {
  77   return NULL_TREE;
  78 }
  79
  80 /* The default post options hook.  */
  81
  82 bool
  83 lhd_post_options (const char **pfilename ATTRIBUTE_UNUSED)
  84 {
  85   return false;
  86 }
  87
  88 /* Called from by print-tree.c.  */
  89
  90 void
  91 lhd_print_tree_nothing (FILE *file ATTRIBUTE_UNUSED,
  92                         tree node ATTRIBUTE_UNUSED,
  93                         int indent ATTRIBUTE_UNUSED)
  94 {
  95 }
  96
  97 /* Called from safe_from_p.  */
  98
  99 int
 100 lhd_safe_from_p (rtx x ATTRIBUTE_UNUSED, tree exp ATTRIBUTE_UNUSED)
 101 {
 102   return 1;
 103 }
 104
 105 /* Called from unsafe_for_reeval.  */
 106
 107 int
 108 lhd_unsafe_for_reeval (tree t ATTRIBUTE_UNUSED)
 109 {
 110   return -1;
 111 }
 112
 113 /* Called from staticp.  */
 114
 115 int
 116 lhd_staticp (tree exp ATTRIBUTE_UNUSED)
 117 {
 118   return 0;
 119 }
 120
 121 /* Called from check_global_declarations.  */
 122
 123 bool
 124 lhd_warn_unused_global_decl (tree decl)
 125 {
 126   /* This is what used to exist in check_global_declarations.  Probably
 127      not many of these actually apply to non-C languages.  */
 128
 129   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_INLINE (decl))
 130     return false;
 131   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 132     return false;
 133   if (DECL_IN_SYSTEM_HEADER (decl))
 134     return false;
 135
 136   return true;
 137 }
 138
 139 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 140 void
 141 lhd_set_decl_assembler_name (tree decl)
 142 {
 143   /* The language-independent code should never use the
 144      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 145      VAR_DECLs for variables with static storage duration need a real
 146      DECL_ASSEMBLER_NAME.  */
 147   if (TREE_CODE (decl) == FUNCTION_DECL
 148       || (TREE_CODE (decl) == VAR_DECL
 149           && (TREE_STATIC (decl)
 150               || DECL_EXTERNAL (decl)
 151               || TREE_PUBLIC (decl))))
 152     /* By default, assume the name to use in assembly code is the
 153        same as that used in the source language.  (That's correct
 154        for C, and GCC used to set DECL_ASSEMBLER_NAME to the same
 155        value as DECL_NAME in build_decl, so this choice provides
 156        backwards compatibility with existing front-ends.  */
 157     SET_DECL_ASSEMBLER_NAME (decl, DECL_NAME (decl));
 158   else
 159     /* Nobody should ever be asking for the DECL_ASSEMBLER_NAME of
 160        these DECLs -- unless they're in language-dependent code, in
 161        which case set_decl_assembler_name hook should handle things.  */
 162     abort ();
 163 }
 164
 165 /* By default we always allow bit-field based optimizations.  */
 166 bool
 167 lhd_can_use_bit_fields_p (void)
 168 {
 169   return true;
 170 }
 171
 172 /* Provide a default routine to clear the binding stack.  This is used
 173    by languages that don't need to do anything special.  */
 174 void
 175 lhd_clear_binding_stack (void)
 176 {
 177   while (! (*lang_hooks.decls.global_bindings_p) ())
 178     poplevel (0, 0, 0);
 179 }
 180
 181 /* Type promotion for variable arguments.  */
 182 tree
 183 lhd_type_promotes_to (tree type ATTRIBUTE_UNUSED)
 184 {
 185   abort ();
 186 }
 187
 188 /* Invalid use of an incomplete type.  */
 189 void
 190 lhd_incomplete_type_error (tree value ATTRIBUTE_UNUSED, tree type)
 191 {
 192   if (TREE_CODE (type) == ERROR_MARK)
 193     return;
 194
 195   abort ();
 196 }
 197
 198 /* Provide a default routine for alias sets that always returns -1.  This
 199    is used by languages that don't need to do anything special.  */
 200
 201 HOST_WIDE_INT
 202 lhd_get_alias_set (tree t ATTRIBUTE_UNUSED)
 203 {
 204   return -1;
 205 }
 206
 207 /* Provide a hook routine for alias sets that always returns 0.  This is
 208    used by languages that haven't deal with alias sets yet.  */
 209
 210 HOST_WIDE_INT
 211 hook_get_alias_set_0 (tree t ATTRIBUTE_UNUSED)
 212 {
 213   return 0;
 214 }
 215
 216 /* This is the default expand_expr function.  */
 217
 218 rtx
 219 lhd_expand_expr (tree t ATTRIBUTE_UNUSED, rtx r ATTRIBUTE_UNUSED,
 220                  enum machine_mode mm ATTRIBUTE_UNUSED,
 221                  int em ATTRIBUTE_UNUSED)
 222 {
 223   abort ();
 224 }
 225
 226 /* This is the default decl_printable_name function.  */
 227
 228 const char *
 229 lhd_decl_printable_name (tree decl, int verbosity ATTRIBUTE_UNUSED)
 230 {
 231   return IDENTIFIER_POINTER (DECL_NAME (decl));
 232 }
 233
 234 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 235    after handling common cases, but before walking code-specific
 236    sub-trees.  If this hook is overridden for a language, it should
 237    handle language-specific tree codes, as well as language-specific
 238    information associated to common tree codes.  If a tree node is
 239    completely handled within this function, it should set *SUBTREES to
 240    0, so that generic handling isn't attempted.  For language-specific
 241    tree codes, generic handling would abort(), so make sure it is set
 242    properly.  Both SUBTREES and *SUBTREES is guaranteed to be nonzero
 243    when the function is called.  */
 244
 245 tree
 246 lhd_tree_inlining_walk_subtrees (tree *tp ATTRIBUTE_UNUSED,
 247                                  int *subtrees ATTRIBUTE_UNUSED,
 248                                  walk_tree_fn func ATTRIBUTE_UNUSED,
 249                                  void *data ATTRIBUTE_UNUSED,
 250                                  void *htab ATTRIBUTE_UNUSED)
 251 {
 252   return NULL_TREE;
 253 }
 254
 255 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 256    determine whether there are language-specific reasons for not
 257    inlining a given function.  */
 258
 259 int
 260 lhd_tree_inlining_cannot_inline_tree_fn (tree *fnp)
 261 {
 262   if (flag_really_no_inline
 263       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 264     return 1;
 265
 266   return 0;
 267 }
 268
 269 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 270    determine whether a function should be considered for inlining even
 271    if it would exceed inlining limits.  */
 272
 273 int
 274 lhd_tree_inlining_disregard_inline_limits (tree fn)
 275 {
 276   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 277     return 1;
 278
 279   return 0;
 280 }
 281
 282 /* lang_hooks.tree_inlining.add_pending_fn_decls is called before
 283    starting to inline a function, to push any language-specific
 284    functions that should not be inlined into the current function,
 285    into VAFNP.  PFN is the top of varray, and should be returned if no
 286    functions are pushed into VAFNP.  The top of the varray should be
 287    returned.  */
 288
 289 tree
 290 lhd_tree_inlining_add_pending_fn_decls (void *vafnp ATTRIBUTE_UNUSED, tree pfn)
 291 {
 292   return pfn;
 293 }
 294
 295 /* lang_hooks.tree_inlining.tree_chain_matters_p indicates whether the
 296    TREE_CHAIN of a language-specific tree node is relevant, i.e.,
 297    whether it should be walked, copied and preserved across copies.  */
 298
 299 int
 300 lhd_tree_inlining_tree_chain_matters_p (tree t ATTRIBUTE_UNUSED)
 301 {
 302   return 0;
 303 }
 304
 305 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 306    whether VT is an automatic variable defined in function FT.  */
 307
 308 int
 309 lhd_tree_inlining_auto_var_in_fn_p (tree var, tree fn)
 310 {
 311   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 312           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 313                && ! TREE_STATIC (var))
 314               || TREE_CODE (var) == LABEL_DECL
 315               || TREE_CODE (var) == RESULT_DECL));
 316 }
 317
 318 /* lang_hooks.tree_inlining.copy_res_decl_for_inlining should return a
 319    declaration for the result RES of function FN to be inlined into
 320    CALLER.  NDP points to an integer that should be set in case a new
 321    declaration wasn't created (presumably because RES was of aggregate
 322    type, such that a TARGET_EXPR is used for the result).  TEXPS is a
 323    pointer to a varray with the stack of TARGET_EXPRs seen while
 324    inlining functions into caller; the top of TEXPS is supposed to
 325    match RES.  */
 326
 327 tree
 328 lhd_tree_inlining_copy_res_decl_for_inlining (tree res, tree fn, tree caller,
 329                                               void *dm ATTRIBUTE_UNUSED,
 330                                               int *ndp ATTRIBUTE_UNUSED,
 331                                               tree return_slot_addr ATTRIBUTE_UNUSED)
 332 {
 333   if (return_slot_addr)
 334     return build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (return_slot_addr)),
 335                    return_slot_addr);
 336   else
 337     return copy_decl_for_inlining (res, fn, caller);
 338 }
 339
 340 /* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
 341    type node representing an anonymous aggregate (union, struct, etc),
 342    i.e., one whose members are in the same scope as the union itself.  */
 343
 344 int
 345 lhd_tree_inlining_anon_aggr_type_p (tree t ATTRIBUTE_UNUSED)
 346 {
 347   return 0;
 348 }
 349
 350 /* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
 351    language-specific bookkeeping necessary for processing
 352    FN. start_inlining returns nonzero if inlining should proceed, zero if
 353    not.
 354
 355    For instance, the C++ version keeps track of template instantiations to
 356    avoid infinite recursion.  */
 357
 358 int
 359 lhd_tree_inlining_start_inlining (tree fn ATTRIBUTE_UNUSED)
 360 {
 361   return 1;
 362 }
 363
 364 void
 365 lhd_tree_inlining_end_inlining (tree fn ATTRIBUTE_UNUSED)
 366 {
 367 }
 368
 369 /* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
 370    language-specific conversion before assigning VALUE to PARM.  */
 371
 372 tree
 373 lhd_tree_inlining_convert_parm_for_inlining (tree parm ATTRIBUTE_UNUSED,
 374                                              tree value,
 375                                              tree fndecl ATTRIBUTE_UNUSED)
 376 {
 377   return value;
 378 }
 379
 380 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 381    nodes.  Returns nonzero if it does not want the usual dumping of the
 382    second argument.  */
 383
 384 bool
 385 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 386 {
 387   return false;
 388 }
 389
 390 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 391    language-specific way.  */
 392
 393 int
 394 lhd_tree_dump_type_quals (tree t)
 395 {
 396   return TYPE_QUALS (t);
 397 }
 398
 399 /* lang_hooks.expr_size: Determine the size of the value of an expression T
 400    in a language-specific way.  Returns a tree for the size in bytes.  */
 401
 402 tree
 403 lhd_expr_size (tree exp)
 404 {
 405   if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
 406       && DECL_SIZE_UNIT (exp) != 0)
 407     return DECL_SIZE_UNIT (exp);
 408   else
 409     return size_in_bytes (TREE_TYPE (exp));
 410 }
 411
 412 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 413    which is a language-specific tree code in category 'x'.  The
 414    default expects never to be called.  */
 415 size_t
 416 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 417 {
 418   abort ();
 419   return 0;
 420 }
 421
 422 /* Return true if decl, which is a function decl, may be called by a
 423    sibcall.  */
 424
 425 bool
 426 lhd_decl_ok_for_sibcall (tree decl ATTRIBUTE_UNUSED)
 427 {
 428   return true;
 429 }
 430
 431 /* lang_hooks.decls.final_write_globals: perform final processing on
 432    global variables.  */
 433 void
 434 write_global_declarations (void)
 435 {
 436   /* Really define vars that have had only a tentative definition.
 437      Really output inline functions that must actually be callable
 438      and have not been output so far.  */
 439
 440   tree globals = (*lang_hooks.decls.getdecls) ();
 441   int len = list_length (globals);
 442   tree *vec = (tree *) xmalloc (sizeof (tree) * len);
 443   int i;
 444   tree decl;
 445
 446   /* Process the decls in reverse order--earliest first.
 447      Put them into VEC from back to front, then take out from front.  */
 448
 449   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
 450     vec[len - i - 1] = decl;
 451
 452   wrapup_global_declarations (vec, len);
 453
 454   check_global_declarations (vec, len);
 455
 456     /* Clean up.  */
 457   free (vec);
 458 }