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.  */
  43
  44 void
  45 lhd_do_nothing_t (t)
  46      tree t ATTRIBUTE_UNUSED;
  47 {
  48 }
  49
  50 /* Do nothing (return the tree node passed).  */
  51
  52 tree
  53 lhd_return_tree (t)
  54      tree t;
  55 {
  56   return t;
  57 }
  58
  59 /* Do nothing (return NULL_TREE).  */
  60
  61 tree
  62 lhd_return_null_tree (t)
  63      tree t ATTRIBUTE_UNUSED;
  64 {
  65   return NULL_TREE;
  66 }
  67
  68 /* Do nothing; the default hook to decode an option.  */
  69
  70 int
  71 lhd_decode_option (argc, argv)
  72      int argc ATTRIBUTE_UNUSED;
  73      char **argv ATTRIBUTE_UNUSED;
  74 {
  75   return 0;
  76 }
  77
  78 /* Called from by print-tree.c.  */
  79
  80 void
  81 lhd_print_tree_nothing (file, node, indent)
  82      FILE *file ATTRIBUTE_UNUSED;
  83      tree node ATTRIBUTE_UNUSED;
  84      int indent ATTRIBUTE_UNUSED;
  85 {
  86 }
  87
  88 /* Called from safe_from_p.  */
  89
  90 int
  91 lhd_safe_from_p (x, exp)
  92      rtx x ATTRIBUTE_UNUSED;
  93      tree exp ATTRIBUTE_UNUSED;
  94 {
  95   return 1;
  96 }
  97
  98 /* Called from unsafe_for_reeval.  */
  99
 100 int
 101 lhd_unsafe_for_reeval (t)
 102      tree t ATTRIBUTE_UNUSED;
 103 {
 104   return -1;
 105 }
 106
 107 /* Called from staticp.  */
 108
 109 int
 110 lhd_staticp (exp)
 111      tree exp ATTRIBUTE_UNUSED;
 112 {
 113   return 0;
 114 }
 115
 116 /* Called from check_global_declarations.  */
 117
 118 bool
 119 lhd_warn_unused_global_decl (decl)
 120      tree decl;
 121 {
 122   /* This is what used to exist in check_global_declarations.  Probably
 123      not many of these actually apply to non-C languages.  */
 124
 125   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_INLINE (decl))
 126     return false;
 127   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 128     return false;
 129   if (DECL_IN_SYSTEM_HEADER (decl))
 130     return false;
 131
 132   return true;
 133 }
 134
 135 /* Called when -dy is given on the command line.  */
 136
 137 void
 138 lhd_set_yydebug (value)
 139      int value;
 140 {
 141   if (value)
 142     fprintf (stderr, "warning: no yacc/bison-generated output to debug!\n");
 143 }
 144
 145 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 146 void
 147 lhd_set_decl_assembler_name (decl)
 148      tree decl;
 149 {
 150   /* The language-independent code should never use the
 151      DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
 152      VAR_DECLs for variables with static storage duration need a real
 153      DECL_ASSEMBLER_NAME.  */
 154   if (TREE_CODE (decl) == FUNCTION_DECL
 155       || (TREE_CODE (decl) == VAR_DECL
 156           && (TREE_STATIC (decl)
 157               || DECL_EXTERNAL (decl)
 158               || TREE_PUBLIC (decl))))
 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     SET_DECL_ASSEMBLER_NAME (decl, DECL_NAME (decl));
 165   else
 166     /* Nobody should ever be asking for the DECL_ASSEMBLER_NAME of
 167        these DECLs -- unless they're in language-dependent code, in
 168        which case set_decl_assembler_name hook should handle things.  */
 169     abort ();
 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 ()
 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 (type)
 184      tree type ATTRIBUTE_UNUSED;
 185 {
 186   abort ();
 187 }
 188
 189 /* Invalid use of an incomplete type.  */
 190 void
 191 lhd_incomplete_type_error (value, type)
 192      tree value ATTRIBUTE_UNUSED, type;
 193 {
 194   if (TREE_CODE (type) == ERROR_MARK)
 195     return;
 196
 197   abort ();
 198 }
 199
 200 /* Provide a default routine for alias sets that always returns -1.  This
 201    is used by languages that don't need to do anything special.  */
 202
 203 HOST_WIDE_INT
 204 lhd_get_alias_set (t)
 205      tree t ATTRIBUTE_UNUSED;
 206 {
 207   return -1;
 208 }
 209
 210 /* Provide a hook routine for alias sets that always returns 0.  This is
 211    used by languages that haven't deal with alias sets yet.  */
 212
 213 HOST_WIDE_INT
 214 hook_get_alias_set_0 (t)
 215      tree t ATTRIBUTE_UNUSED;
 216 {
 217   return 0;
 218 }
 219
 220 /* This is the default expand_expr function.  */
 221
 222 rtx
 223 lhd_expand_expr (t, r, mm, em)
 224      tree t ATTRIBUTE_UNUSED;
 225      rtx r ATTRIBUTE_UNUSED;
 226      enum machine_mode mm ATTRIBUTE_UNUSED;
 227      int em ATTRIBUTE_UNUSED;
 228 {
 229   abort ();
 230 }
 231
 232 /* This is the default decl_printable_name function.  */
 233
 234 const char *
 235 lhd_decl_printable_name (decl, verbosity)
 236      tree decl;
 237      int verbosity ATTRIBUTE_UNUSED;
 238 {
 239   return IDENTIFIER_POINTER (DECL_NAME (decl));
 240 }
 241
 242 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 243    after handling common cases, but before walking code-specific
 244    sub-trees.  If this hook is overridden for a language, it should
 245    handle language-specific tree codes, as well as language-specific
 246    information associated to common tree codes.  If a tree node is
 247    completely handled within this function, it should set *SUBTREES to
 248    0, so that generic handling isn't attempted.  For language-specific
 249    tree codes, generic handling would abort(), so make sure it is set
 250    properly.  Both SUBTREES and *SUBTREES is guaranteed to be non-zero
 251    when the function is called.  */
 252
 253 tree
 254 lhd_tree_inlining_walk_subtrees (tp,subtrees,func,data,htab)
 255      tree *tp ATTRIBUTE_UNUSED;
 256      int *subtrees ATTRIBUTE_UNUSED;
 257      walk_tree_fn func ATTRIBUTE_UNUSED;
 258      void *data ATTRIBUTE_UNUSED;
 259      void *htab ATTRIBUTE_UNUSED;
 260 {
 261   return NULL_TREE;
 262 }
 263
 264 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 265    determine whether there are language-specific reasons for not
 266    inlining a given function.  */
 267
 268 int
 269 lhd_tree_inlining_cannot_inline_tree_fn (fnp)
 270      tree *fnp;
 271 {
 272   if (flag_really_no_inline
 273       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 274     return 1;
 275
 276   return 0;
 277 }
 278
 279 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 280    determine whether a function should be considered for inlining even
 281    if it would exceed inlining limits.  */
 282
 283 int
 284 lhd_tree_inlining_disregard_inline_limits (fn)
 285      tree fn;
 286 {
 287   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 288     return 1;
 289
 290   return 0;
 291 }
 292
 293 /* lang_hooks.tree_inlining.add_pending_fn_decls is called before
 294    starting to inline a function, to push any language-specific
 295    functions that should not be inlined into the current function,
 296    into VAFNP.  PFN is the top of varray, and should be returned if no
 297    functions are pushed into VAFNP.  The top of the varray should be
 298    returned.  */
 299
 300 tree
 301 lhd_tree_inlining_add_pending_fn_decls (vafnp, pfn)
 302      void *vafnp ATTRIBUTE_UNUSED;
 303      tree pfn;
 304 {
 305   return pfn;
 306 }
 307
 308 /* lang_hooks.tree_inlining.tree_chain_matters_p indicates whether the
 309    TREE_CHAIN of a language-specific tree node is relevant, i.e.,
 310    whether it should be walked, copied and preserved across copies.  */
 311
 312 int
 313 lhd_tree_inlining_tree_chain_matters_p (t)
 314      tree t ATTRIBUTE_UNUSED;
 315 {
 316   return 0;
 317 }
 318
 319 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 320    whether VT is an automatic variable defined in function FT.  */
 321
 322 int
 323 lhd_tree_inlining_auto_var_in_fn_p (var, fn)
 324      tree var, fn;
 325 {
 326   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 327           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 328                && ! TREE_STATIC (var))
 329               || TREE_CODE (var) == LABEL_DECL
 330               || TREE_CODE (var) == RESULT_DECL));
 331 }
 332
 333 /* lang_hooks.tree_inlining.copy_res_decl_for_inlining should return a
 334    declaration for the result RES of function FN to be inlined into
 335    CALLER.  NDP points to an integer that should be set in case a new
 336    declaration wasn't created (presumably because RES was of aggregate
 337    type, such that a TARGET_EXPR is used for the result).  TEXPS is a
 338    pointer to a varray with the stack of TARGET_EXPRs seen while
 339    inlining functions into caller; the top of TEXPS is supposed to
 340    match RES.  */
 341
 342 tree
 343 lhd_tree_inlining_copy_res_decl_for_inlining (res, fn, caller,
 344                                               dm, ndp, texps)
 345      tree res, fn, caller;
 346      void *dm ATTRIBUTE_UNUSED;
 347      int *ndp ATTRIBUTE_UNUSED;
 348      void *texps ATTRIBUTE_UNUSED;
 349 {
 350   return copy_decl_for_inlining (res, fn, caller);
 351 }
 352
 353 /* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
 354    type node representing an anonymous aggregate (union, struct, etc),
 355    i.e., one whose members are in the same scope as the union itself.  */
 356
 357 int
 358 lhd_tree_inlining_anon_aggr_type_p (t)
 359      tree t ATTRIBUTE_UNUSED;
 360 {
 361   return 0;
 362 }
 363
 364 /* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
 365    language-specific bookkeeping necessary for processing
 366    FN. start_inlining returns non-zero if inlining should proceed, zero if
 367    not.
 368
 369    For instance, the C++ version keeps track of template instantiations to
 370    avoid infinite recursion.  */
 371
 372 int
 373 lhd_tree_inlining_start_inlining (fn)
 374      tree fn ATTRIBUTE_UNUSED;
 375 {
 376   return 1;
 377 }
 378
 379 void
 380 lhd_tree_inlining_end_inlining (fn)
 381      tree fn ATTRIBUTE_UNUSED;
 382 {
 383 }
 384
 385 /* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
 386    language-specific conversion before assigning VALUE to PARM.  */
 387
 388 tree
 389 lhd_tree_inlining_convert_parm_for_inlining (parm, value, fndecl)
 390      tree parm ATTRIBUTE_UNUSED;
 391      tree value;
 392      tree fndecl ATTRIBUTE_UNUSED;
 393 {
 394   return value;
 395 }
 396
 397 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 398    nodes.  Returns non-zero if it does not want the usual dumping of the
 399    second argument.  */
 400
 401 int
 402 lhd_tree_dump_dump_tree (di, t)
 403      void *di ATTRIBUTE_UNUSED;
 404      tree t ATTRIBUTE_UNUSED;
 405 {
 406   return 0;
 407 }
 408
 409 /* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
 410    language-specific way.  */
 411
 412 int
 413 lhd_tree_dump_type_quals (t)
 414      tree t;
 415 {
 416   return TYPE_QUALS (t);
 417 }
 418