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 /* Provide a default routine for alias sets that always returns -1.  This
 182    is used by languages that don't need to do anything special.  */
 183
 184 HOST_WIDE_INT
 185 lhd_get_alias_set (t)
 186      tree t ATTRIBUTE_UNUSED;
 187 {
 188   return -1;
 189 }
 190
 191 /* Provide a hook routine for alias sets that always returns 0.  This is
 192    used by languages that haven't deal with alias sets yet.  */
 193
 194 HOST_WIDE_INT
 195 hook_get_alias_set_0 (t)
 196      tree t ATTRIBUTE_UNUSED;
 197 {
 198   return 0;
 199 }
 200
 201 /* This is the default expand_expr function.  */
 202
 203 rtx
 204 lhd_expand_expr (t, r, mm, em)
 205      tree t ATTRIBUTE_UNUSED;
 206      rtx r ATTRIBUTE_UNUSED;
 207      enum machine_mode mm ATTRIBUTE_UNUSED;
 208      int em ATTRIBUTE_UNUSED;
 209 {
 210   abort ();
 211 }
 212
 213 /* This is the default decl_printable_name function.  */
 214
 215 const char *
 216 lhd_decl_printable_name (decl, verbosity)
 217      tree decl;
 218      int verbosity ATTRIBUTE_UNUSED;
 219 {
 220   return IDENTIFIER_POINTER (DECL_NAME (decl));
 221 }
 222
 223 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 224    after handling common cases, but before walking code-specific
 225    sub-trees.  If this hook is overridden for a language, it should
 226    handle language-specific tree codes, as well as language-specific
 227    information associated to common tree codes.  If a tree node is
 228    completely handled within this function, it should set *SUBTREES to
 229    0, so that generic handling isn't attempted.  For language-specific
 230    tree codes, generic handling would abort(), so make sure it is set
 231    properly.  Both SUBTREES and *SUBTREES is guaranteed to be non-zero
 232    when the function is called.  */
 233
 234 tree
 235 lhd_tree_inlining_walk_subtrees (tp,subtrees,func,data,htab)
 236      tree *tp ATTRIBUTE_UNUSED;
 237      int *subtrees ATTRIBUTE_UNUSED;
 238      walk_tree_fn func ATTRIBUTE_UNUSED;
 239      void *data ATTRIBUTE_UNUSED;
 240      void *htab ATTRIBUTE_UNUSED;
 241 {
 242   return NULL_TREE;
 243 }
 244
 245 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 246    determine whether there are language-specific reasons for not
 247    inlining a given function.  */
 248
 249 int
 250 lhd_tree_inlining_cannot_inline_tree_fn (fnp)
 251      tree *fnp;
 252 {
 253   if (flag_really_no_inline
 254       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 255     return 1;
 256
 257   return 0;
 258 }
 259
 260 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 261    determine whether a function should be considered for inlining even
 262    if it would exceed inlining limits.  */
 263
 264 int
 265 lhd_tree_inlining_disregard_inline_limits (fn)
 266      tree fn;
 267 {
 268   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 269     return 1;
 270
 271   return 0;
 272 }
 273
 274 /* lang_hooks.tree_inlining.add_pending_fn_decls is called before
 275    starting to inline a function, to push any language-specific
 276    functions that should not be inlined into the current function,
 277    into VAFNP.  PFN is the top of varray, and should be returned if no
 278    functions are pushed into VAFNP.  The top of the varray should be
 279    returned.  */
 280
 281 tree
 282 lhd_tree_inlining_add_pending_fn_decls (vafnp, pfn)
 283      void *vafnp ATTRIBUTE_UNUSED;
 284      tree pfn;
 285 {
 286   return pfn;
 287 }
 288
 289 /* lang_hooks.tree_inlining.tree_chain_matters_p indicates whether the
 290    TREE_CHAIN of a language-specific tree node is relevant, i.e.,
 291    whether it should be walked, copied and preserved across copies.  */
 292
 293 int
 294 lhd_tree_inlining_tree_chain_matters_p (t)
 295      tree t ATTRIBUTE_UNUSED;
 296 {
 297   return 0;
 298 }
 299
 300 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 301    whether VT is an automatic variable defined in function FT.  */
 302
 303 int
 304 lhd_tree_inlining_auto_var_in_fn_p (var, fn)
 305      tree var, fn;
 306 {
 307   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 308           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 309                && ! TREE_STATIC (var))
 310               || TREE_CODE (var) == LABEL_DECL
 311               || TREE_CODE (var) == RESULT_DECL));
 312 }
 313
 314 /* lang_hooks.tree_inlining.copy_res_decl_for_inlining should return a
 315    declaration for the result RES of function FN to be inlined into
 316    CALLER.  NDP points to an integer that should be set in case a new
 317    declaration wasn't created (presumably because RES was of aggregate
 318    type, such that a TARGET_EXPR is used for the result).  TEXPS is a
 319    pointer to a varray with the stack of TARGET_EXPRs seen while
 320    inlining functions into caller; the top of TEXPS is supposed to
 321    match RES.  */
 322
 323 tree
 324 lhd_tree_inlining_copy_res_decl_for_inlining (res, fn, caller,
 325                                               dm, ndp, texps)
 326      tree res, fn, caller;
 327      void *dm ATTRIBUTE_UNUSED;
 328      int *ndp ATTRIBUTE_UNUSED;
 329      void *texps ATTRIBUTE_UNUSED;
 330 {
 331   return copy_decl_for_inlining (res, fn, caller);
 332 }
 333
 334 /* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
 335    type node representing an anonymous aggregate (union, struct, etc),
 336    i.e., one whose members are in the same scope as the union itself.  */
 337
 338 int
 339 lhd_tree_inlining_anon_aggr_type_p (t)
 340      tree t ATTRIBUTE_UNUSED;
 341 {
 342   return 0;
 343 }
 344
 345 /* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
 346    language-specific bookkeeping necessary for processing
 347    FN. start_inlining returns non-zero if inlining should proceed, zero if
 348    not.
 349
 350    For instance, the C++ version keeps track of template instantiations to
 351    avoid infinite recursion.  */
 352
 353 int
 354 lhd_tree_inlining_start_inlining (fn)
 355      tree fn ATTRIBUTE_UNUSED;
 356 {
 357   return 1;
 358 }
 359
 360 void
 361 lhd_tree_inlining_end_inlining (fn)
 362      tree fn ATTRIBUTE_UNUSED;
 363 {
 364 }
 365
 366 /* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
 367    language-specific conversion before assigning VALUE to PARM.  */
 368
 369 tree
 370 lhd_tree_inlining_convert_parm_for_inlining (parm, value, fndecl)
 371      tree parm ATTRIBUTE_UNUSED;
 372      tree value;
 373      tree fndecl ATTRIBUTE_UNUSED;
 374 {
 375   return value;
 376 }
 377
 378 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 379    nodes.  Returns non-zero if it does not want the usual dumping of the
 380    second argument.  */
 381
 382 int
 383 lhd_tree_dump_dump_tree (di, t)
 384      void *di ATTRIBUTE_UNUSED;
 385      tree t ATTRIBUTE_UNUSED;
 386 {
 387   return 0;
 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 (t)
 395      tree t;
 396 {
 397   return TYPE_QUALS (t);
 398 }
 399