gcc/langhooks.c

   1 /* Default language-specific hooks.
   2    Copyright 2001, 2002, 2003, 2004 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 "tree-gimple.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 #include "ggc.h"
  37 #include "diagnostic.h"
  38
  39 /* Do nothing; in many cases the default hook.  */
  40
  41 void
  42 lhd_do_nothing (void)
  43 {
  44 }
  45
  46 /* Do nothing (tree).  */
  47
  48 void
  49 lhd_do_nothing_t (tree ARG_UNUSED (t))
  50 {
  51 }
  52
  53 /* Do nothing (int).  */
  54
  55 void
  56 lhd_do_nothing_i (int ARG_UNUSED (i))
  57 {
  58 }
  59
  60 /* Do nothing (int, int, int).  Return NULL_TREE.  */
  61
  62 tree
  63 lhd_do_nothing_iii_return_null_tree (int ARG_UNUSED (i),
  64                                      int ARG_UNUSED (j),
  65                                      int ARG_UNUSED (k))
  66 {
  67   return NULL_TREE;
  68 }
  69
  70 /* Do nothing (function).  */
  71
  72 void
  73 lhd_do_nothing_f (struct function * ARG_UNUSED (f))
  74 {
  75 }
  76
  77 /* Do nothing (return the tree node passed).  */
  78
  79 tree
  80 lhd_return_tree (tree t)
  81 {
  82   return t;
  83 }
  84
  85 /* Do nothing (return NULL_TREE).  */
  86
  87 tree
  88 lhd_return_null_tree_v (void)
  89 {
  90   return NULL_TREE;
  91 }
  92
  93 /* Do nothing (return NULL_TREE).  */
  94
  95 tree
  96 lhd_return_null_tree (tree ARG_UNUSED (t))
  97 {
  98   return NULL_TREE;
  99 }
 100
 101 /* The default post options hook.  */
 102
 103 bool
 104 lhd_post_options (const char ** ARG_UNUSED (pfilename))
 105 {
 106   return false;
 107 }
 108
 109 /* Called from by print-tree.c.  */
 110
 111 void
 112 lhd_print_tree_nothing (FILE * ARG_UNUSED (file),
 113                         tree ARG_UNUSED (node),
 114                         int ARG_UNUSED (indent))
 115 {
 116 }
 117
 118 /* Called from safe_from_p.  */
 119
 120 int
 121 lhd_safe_from_p (rtx ARG_UNUSED (x), tree ARG_UNUSED (exp))
 122 {
 123   return 1;
 124 }
 125
 126 /* Called from staticp.  */
 127
 128 tree
 129 lhd_staticp (tree ARG_UNUSED (exp))
 130 {
 131   return NULL;
 132 }
 133
 134 /* Called from check_global_declarations.  */
 135
 136 bool
 137 lhd_warn_unused_global_decl (tree decl)
 138 {
 139   /* This is what used to exist in check_global_declarations.  Probably
 140      not many of these actually apply to non-C languages.  */
 141
 142   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_INLINE (decl))
 143     return false;
 144   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 145     return false;
 146   if (DECL_IN_SYSTEM_HEADER (decl))
 147     return false;
 148
 149   return true;
 150 }
 151
 152 /* Set the DECL_ASSEMBLER_NAME for DECL.  */
 153 void
 154 lhd_set_decl_assembler_name (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     {
 166       /* By default, assume the name to use in assembly code is the
 167          same as that used in the source language.  (That's correct
 168          for C, and GCC used to set DECL_ASSEMBLER_NAME to the same
 169          value as DECL_NAME in build_decl, so this choice provides
 170          backwards compatibility with existing front-ends.
 171
 172          Can't use just the variable's own name for a variable whose
 173          scope is less than the whole compilation.  Concatenate a
 174          distinguishing number - we use the DECL_UID.  */
 175       if (TREE_PUBLIC (decl) || DECL_CONTEXT (decl) == NULL_TREE)
 176         SET_DECL_ASSEMBLER_NAME (decl, DECL_NAME (decl));
 177       else
 178         {
 179           const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
 180           char *label;
 181
 182           ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
 183           SET_DECL_ASSEMBLER_NAME (decl, get_identifier (label));
 184         }
 185     }
 186   else
 187     /* Nobody should ever be asking for the DECL_ASSEMBLER_NAME of
 188        these DECLs -- unless they're in language-dependent code, in
 189        which case set_decl_assembler_name hook should handle things.  */
 190     abort ();
 191 }
 192
 193 /* By default we always allow bit-field based optimizations.  */
 194 bool
 195 lhd_can_use_bit_fields_p (void)
 196 {
 197   return true;
 198 }
 199
 200 /* Type promotion for variable arguments.  */
 201 tree
 202 lhd_type_promotes_to (tree ARG_UNUSED (type))
 203 {
 204   abort ();
 205 }
 206
 207 /* Registration of machine- or os-specific builtin types.  */
 208 void
 209 lhd_register_builtin_type (tree ARG_UNUSED (type),
 210                            const char * ARG_UNUSED (name))
 211 {
 212 }
 213
 214 /* Invalid use of an incomplete type.  */
 215 void
 216 lhd_incomplete_type_error (tree ARG_UNUSED (value), tree type)
 217 {
 218   if (TREE_CODE (type) == ERROR_MARK)
 219     return;
 220
 221   abort ();
 222 }
 223
 224 /* Provide a default routine for alias sets that always returns -1.  This
 225    is used by languages that don't need to do anything special.  */
 226
 227 HOST_WIDE_INT
 228 lhd_get_alias_set (tree ARG_UNUSED (t))
 229 {
 230   return -1;
 231 }
 232
 233 /* Provide a hook routine for alias sets that always returns 0.  This is
 234    used by languages that haven't deal with alias sets yet.  */
 235
 236 HOST_WIDE_INT
 237 hook_get_alias_set_0 (tree ARG_UNUSED (t))
 238 {
 239   return 0;
 240 }
 241
 242 /* This is the default expand_expr function.  */
 243
 244 rtx
 245 lhd_expand_expr (tree ARG_UNUSED (t), rtx ARG_UNUSED (r),
 246                  enum machine_mode ARG_UNUSED (mm),
 247                  int ARG_UNUSED (em),
 248                  rtx * ARG_UNUSED (a))
 249 {
 250   abort ();
 251 }
 252
 253 /* The default language-specific function for expanding a decl.  After
 254    the language-independent cases are handled, this function will be
 255    called.  If this function is not defined, it is assumed that
 256    declarations other than those for variables and labels do not require
 257    any RTL generation.  */
 258
 259 int
 260 lhd_expand_decl (tree ARG_UNUSED (t))
 261 {
 262   return 0;
 263 }
 264
 265 /* This is the default decl_printable_name function.  */
 266
 267 const char *
 268 lhd_decl_printable_name (tree decl, int ARG_UNUSED (verbosity))
 269 {
 270   gcc_assert (decl && DECL_NAME (decl));
 271   return IDENTIFIER_POINTER (DECL_NAME (decl));
 272 }
 273
 274 /* This compares two types for equivalence ("compatible" in C-based languages).
 275    This routine should only return 1 if it is sure.  It should not be used
 276    in contexts where erroneously returning 0 causes problems.  */
 277
 278 int
 279 lhd_types_compatible_p (tree x, tree y)
 280 {
 281   return TYPE_MAIN_VARIANT (x) == TYPE_MAIN_VARIANT (y);
 282 }
 283
 284 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
 285    after handling common cases, but before walking code-specific
 286    sub-trees.  If this hook is overridden for a language, it should
 287    handle language-specific tree codes, as well as language-specific
 288    information associated to common tree codes.  If a tree node is
 289    completely handled within this function, it should set *SUBTREES to
 290    0, so that generic handling isn't attempted.  For language-specific
 291    tree codes, generic handling would abort(), so make sure it is set
 292    properly.  Both SUBTREES and *SUBTREES is guaranteed to be nonzero
 293    when the function is called.  */
 294
 295 tree
 296 lhd_tree_inlining_walk_subtrees (tree *tp ATTRIBUTE_UNUSED,
 297                                  int *subtrees ATTRIBUTE_UNUSED,
 298                                  walk_tree_fn func ATTRIBUTE_UNUSED,
 299                                  void *data ATTRIBUTE_UNUSED,
 300                                  void *htab ATTRIBUTE_UNUSED)
 301 {
 302   return NULL_TREE;
 303 }
 304
 305 /* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
 306    determine whether there are language-specific reasons for not
 307    inlining a given function.  */
 308
 309 int
 310 lhd_tree_inlining_cannot_inline_tree_fn (tree *fnp)
 311 {
 312   if (flag_really_no_inline
 313       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
 314     return 1;
 315
 316   return 0;
 317 }
 318
 319 /* lang_hooks.tree_inlining.disregard_inline_limits is called to
 320    determine whether a function should be considered for inlining even
 321    if it would exceed inlining limits.  */
 322
 323 int
 324 lhd_tree_inlining_disregard_inline_limits (tree fn)
 325 {
 326   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
 327     return 1;
 328
 329   return 0;
 330 }
 331
 332 /* lang_hooks.tree_inlining.add_pending_fn_decls is called before
 333    starting to inline a function, to push any language-specific
 334    functions that should not be inlined into the current function,
 335    into VAFNP.  PFN is the top of varray, and should be returned if no
 336    functions are pushed into VAFNP.  The top of the varray should be
 337    returned.  */
 338
 339 tree
 340 lhd_tree_inlining_add_pending_fn_decls (void *vafnp ATTRIBUTE_UNUSED, tree pfn)
 341 {
 342   return pfn;
 343 }
 344
 345 /* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
 346    whether VT is an automatic variable defined in function FT.  */
 347
 348 int
 349 lhd_tree_inlining_auto_var_in_fn_p (tree var, tree fn)
 350 {
 351   return (DECL_P (var) && DECL_CONTEXT (var) == fn
 352           && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
 353                && ! TREE_STATIC (var))
 354               || TREE_CODE (var) == LABEL_DECL
 355               || TREE_CODE (var) == RESULT_DECL));
 356 }
 357
 358 /* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
 359    type node representing an anonymous aggregate (union, struct, etc),
 360    i.e., one whose members are in the same scope as the union itself.  */
 361
 362 int
 363 lhd_tree_inlining_anon_aggr_type_p (tree t ATTRIBUTE_UNUSED)
 364 {
 365   return 0;
 366 }
 367
 368 /* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
 369    language-specific bookkeeping necessary for processing
 370    FN. start_inlining returns nonzero if inlining should proceed, zero if
 371    not.
 372
 373    For instance, the C++ version keeps track of template instantiations to
 374    avoid infinite recursion.  */
 375
 376 int
 377 lhd_tree_inlining_start_inlining (tree fn ATTRIBUTE_UNUSED)
 378 {
 379   return 1;
 380 }
 381
 382 void
 383 lhd_tree_inlining_end_inlining (tree fn ATTRIBUTE_UNUSED)
 384 {
 385 }
 386
 387 /* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
 388    language-specific conversion before assigning VALUE to PARM.  */
 389
 390 tree
 391 lhd_tree_inlining_convert_parm_for_inlining (tree parm ATTRIBUTE_UNUSED,
 392                                              tree value,
 393                                              tree fndecl ATTRIBUTE_UNUSED,
 394                                              int argnum ATTRIBUTE_UNUSED)
 395 {
 396   return value;
 397 }
 398
 399 /* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
 400    nodes.  Returns nonzero if it does not want the usual dumping of the
 401    second argument.  */
 402
 403 bool
 404 lhd_tree_dump_dump_tree (void *di ATTRIBUTE_UNUSED, tree t ATTRIBUTE_UNUSED)
 405 {
 406   return false;
 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 (tree t)
 414 {
 415   return TYPE_QUALS (t);
 416 }
 417
 418 /* lang_hooks.expr_size: Determine the size of the value of an expression T
 419    in a language-specific way.  Returns a tree for the size in bytes.  */
 420
 421 tree
 422 lhd_expr_size (tree exp)
 423 {
 424   if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
 425       && DECL_SIZE_UNIT (exp) != 0)
 426     return DECL_SIZE_UNIT (exp);
 427   else
 428     return size_in_bytes (TREE_TYPE (exp));
 429 }
 430
 431 /* lang_hooks.gimplify_expr re-writes *EXPR_P into GIMPLE form.  */
 432
 433 int
 434 lhd_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED, tree *pre_p ATTRIBUTE_UNUSED,
 435                    tree *post_p ATTRIBUTE_UNUSED)
 436 {
 437   return GS_UNHANDLED;
 438 }
 439
 440 /* lang_hooks.tree_size: Determine the size of a tree with code C,
 441    which is a language-specific tree code in category 'x'.  The
 442    default expects never to be called.  */
 443 size_t
 444 lhd_tree_size (enum tree_code c ATTRIBUTE_UNUSED)
 445 {
 446   abort ();
 447   return 0;
 448 }
 449
 450 /* Return true if decl, which is a function decl, may be called by a
 451    sibcall.  */
 452
 453 bool
 454 lhd_decl_ok_for_sibcall (tree decl ATTRIBUTE_UNUSED)
 455 {
 456   return true;
 457 }
 458
 459 /* Return the COMDAT group into which DECL should be placed.  */
 460
 461 const char *
 462 lhd_comdat_group (tree decl)
 463 {
 464   return IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
 465 }
 466
 467 /* lang_hooks.decls.final_write_globals: perform final processing on
 468    global variables.  */
 469 void
 470 write_global_declarations (void)
 471 {
 472   /* Really define vars that have had only a tentative definition.
 473      Really output inline functions that must actually be callable
 474      and have not been output so far.  */
 475
 476   tree globals = lang_hooks.decls.getdecls ();
 477   int len = list_length (globals);
 478   tree *vec = xmalloc (sizeof (tree) * len);
 479   int i;
 480   tree decl;
 481
 482   /* Process the decls in reverse order--earliest first.
 483      Put them into VEC from back to front, then take out from front.  */
 484
 485   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
 486     vec[len - i - 1] = decl;
 487
 488   wrapup_global_declarations (vec, len);
 489
 490   check_global_declarations (vec, len);
 491
 492     /* Clean up.  */
 493   free (vec);
 494 }
 495
 496 /* Called to perform language-specific initialization of CTX.  */
 497 void
 498 lhd_initialize_diagnostics (struct diagnostic_context *ctx ATTRIBUTE_UNUSED)
 499 {
 500 }
 501
 502 /* The default function to print out name of current function that caused
 503    an error.  */
 504 void
 505 lhd_print_error_function (diagnostic_context *context, const char *file)
 506 {
 507   if (diagnostic_last_function_changed (context))
 508     {
 509       const char *old_prefix = context->printer->prefix;
 510       char *new_prefix = file ? file_name_as_prefix (file) : NULL;
 511
 512       pp_set_prefix (context->printer, new_prefix);
 513
 514       if (current_function_decl == NULL)
 515         pp_printf (context->printer, "At top level:");
 516       else
 517         {
 518           if (TREE_CODE (TREE_TYPE (current_function_decl)) == METHOD_TYPE)
 519             pp_printf
 520               (context->printer, "In member function `%s':",
 521                lang_hooks.decl_printable_name (current_function_decl, 2));
 522           else
 523             pp_printf
 524               (context->printer, "In function `%s':",
 525                lang_hooks.decl_printable_name (current_function_decl, 2));
 526         }
 527
 528       diagnostic_set_last_function (context);
 529       pp_flush (context->printer);
 530       context->printer->prefix = old_prefix;
 531       free ((char*) new_prefix);
 532     }
 533 }
 534
 535 tree
 536 lhd_callgraph_analyze_expr (tree *tp ATTRIBUTE_UNUSED,
 537                             int *walk_subtrees ATTRIBUTE_UNUSED,
 538                             tree decl ATTRIBUTE_UNUSED)
 539 {
 540   return NULL;
 541 }
 542
 543 tree
 544 lhd_make_node (enum tree_code code)
 545 {
 546   return make_node (code);
 547 }