gcc/cp/cp-objcp-common.c

   1 /* Some code common to C++ and ObjC++ front ends.
   2    Copyright (C) 2004-2017 Free Software Foundation, Inc.
   3    Contributed by Ziemowit Laski  <zlaski@apple.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "cp-tree.h"
  25 #include "cp-objcp-common.h"
  26 #include "dwarf2.h"
  27
  28 /* Special routine to get the alias set for C++.  */
  29
  30 alias_set_type
  31 cxx_get_alias_set (tree t)
  32 {
  33   if (IS_FAKE_BASE_TYPE (t))
  34     /* The base variant of a type must be in the same alias set as the
  35        complete type.  */
  36     return get_alias_set (TYPE_CONTEXT (t));
  37
  38   /* Punt on PMFs until we canonicalize functions properly.  */
  39   if (TYPE_PTRMEMFUNC_P (t)
  40       || (POINTER_TYPE_P (t)
  41           && TYPE_PTRMEMFUNC_P (TREE_TYPE (t))))
  42     return 0;
  43
  44   return c_common_get_alias_set (t);
  45 }
  46
  47 /* Called from check_global_declaration.  */
  48
  49 bool
  50 cxx_warn_unused_global_decl (const_tree decl)
  51 {
  52   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
  53     return false;
  54   if (DECL_IN_SYSTEM_HEADER (decl))
  55     return false;
  56
  57   return true;
  58 }
  59
  60 /* Langhook for tree_size: determine size of our 'x' and 'c' nodes.  */
  61 size_t
  62 cp_tree_size (enum tree_code code)
  63 {
  64   gcc_checking_assert (code >= NUM_TREE_CODES);
  65   switch (code)
  66     {
  67     case PTRMEM_CST:            return sizeof (ptrmem_cst);
  68     case BASELINK:              return sizeof (tree_baselink);
  69     case TEMPLATE_PARM_INDEX:   return sizeof (template_parm_index);
  70     case DEFAULT_ARG:           return sizeof (tree_default_arg);
  71     case DEFERRED_NOEXCEPT:     return sizeof (tree_deferred_noexcept);
  72     case OVERLOAD:              return sizeof (tree_overload);
  73     case STATIC_ASSERT:         return sizeof (tree_static_assert);
  74     case TYPE_ARGUMENT_PACK:
  75     case TYPE_PACK_EXPANSION:   return sizeof (tree_type_non_common);
  76     case NONTYPE_ARGUMENT_PACK:
  77     case EXPR_PACK_EXPANSION:   return sizeof (tree_exp);
  78     case ARGUMENT_PACK_SELECT:  return sizeof (tree_argument_pack_select);
  79     case TRAIT_EXPR:            return sizeof (tree_trait_expr);
  80     case LAMBDA_EXPR:           return sizeof (tree_lambda_expr);
  81     case TEMPLATE_INFO:         return sizeof (tree_template_info);
  82     case CONSTRAINT_INFO:       return sizeof (tree_constraint_info);
  83     case USERDEF_LITERAL:       return sizeof (tree_userdef_literal);
  84     case TEMPLATE_DECL:         return sizeof (tree_template_decl);
  85     default:
  86       switch (TREE_CODE_CLASS (code))
  87         {
  88         case tcc_declaration:   return sizeof (tree_decl_non_common);
  89         case tcc_type:          return sizeof (tree_type_non_common);
  90         default: gcc_unreachable ();
  91         }
  92     }
  93   /* NOTREACHED */
  94 }
  95
  96 /* Returns true if T is a variably modified type, in the sense of C99.
  97    FN is as passed to variably_modified_p.
  98    This routine needs only check cases that cannot be handled by the
  99    language-independent logic in tree.c.  */
 100
 101 bool
 102 cp_var_mod_type_p (tree type, tree fn)
 103 {
 104   /* If TYPE is a pointer-to-member, it is variably modified if either
 105      the class or the member are variably modified.  */
 106   if (TYPE_PTRMEM_P (type))
 107     return (variably_modified_type_p (TYPE_PTRMEM_CLASS_TYPE (type), fn)
 108             || variably_modified_type_p (TYPE_PTRMEM_POINTED_TO_TYPE (type),
 109                                          fn));
 110
 111   /* All other types are not variably modified.  */
 112   return false;
 113 }
 114
 115 /* This compares two types for equivalence ("compatible" in C-based languages).
 116    This routine should only return 1 if it is sure.  It should not be used
 117    in contexts where erroneously returning 0 causes problems.  */
 118
 119 int
 120 cxx_types_compatible_p (tree x, tree y)
 121 {
 122   return same_type_ignoring_top_level_qualifiers_p (x, y);
 123 }
 124
 125 struct debug_type_hasher : ggc_cache_ptr_hash<tree_map>
 126 {
 127   static hashval_t hash (tree_map *m) { return tree_map_hash (m); }
 128   static bool equal (tree_map *a, tree_map *b) { return tree_map_eq (a, b); }
 129
 130   static int
 131   keep_cache_entry (tree_map *&e)
 132   {
 133     return ggc_marked_p (e->base.from);
 134   }
 135 };
 136
 137 static GTY((cache)) hash_table<debug_type_hasher> *debug_type_hash;
 138
 139 /* Return a type to use in the debug info instead of TYPE, or NULL_TREE to
 140    keep TYPE.  */
 141
 142 tree
 143 cp_get_debug_type (const_tree type)
 144 {
 145   if (TYPE_PTRMEMFUNC_P (type) && !typedef_variant_p (type))
 146     {
 147       if (debug_type_hash == NULL)
 148         debug_type_hash = hash_table<debug_type_hasher>::create_ggc (512);
 149
 150       /* We cannot simply use build_offset_type here because the function uses
 151          the type canonicalization hashtable, which is GC-ed, so its behavior
 152          depends on the actual collection points.  Since we are building these
 153          types on the fly for the debug info only, they would not be attached
 154          to any GC root and always be swept, so we would make the contents of
 155          the debug info depend on the collection points.  */
 156       struct tree_map in, *h, **slot;
 157
 158       in.base.from = CONST_CAST_TREE (type);
 159       in.hash = htab_hash_pointer (type);
 160       slot = debug_type_hash->find_slot_with_hash (&in, in.hash, INSERT);
 161       if (*slot)
 162         return (*slot)->to;
 163
 164       tree t = build_offset_type (TYPE_PTRMEMFUNC_OBJECT_TYPE (type),
 165                                   TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (type)));
 166
 167       h = ggc_alloc<tree_map> ();
 168       h->base.from = CONST_CAST_TREE (type);
 169       h->hash = htab_hash_pointer (type);
 170       h->to = t;
 171       *slot = h;
 172
 173       return t;
 174     }
 175
 176   return NULL_TREE;
 177 }
 178
 179 /* Return -1 if dwarf ATTR shouldn't be added for DECL, or the attribute
 180    value otherwise.  */
 181 int
 182 cp_decl_dwarf_attribute (const_tree decl, int attr)
 183 {
 184   if (decl == NULL_TREE)
 185     return -1;
 186
 187   switch (attr)
 188     {
 189     case DW_AT_explicit:
 190       if (TREE_CODE (decl) == FUNCTION_DECL
 191           && DECL_LANG_SPECIFIC (STRIP_TEMPLATE (decl))
 192           && DECL_NONCONVERTING_P (decl))
 193         return 1;
 194       break;
 195
 196     case DW_AT_deleted:
 197       if (TREE_CODE (decl) == FUNCTION_DECL
 198           && DECL_LANG_SPECIFIC (STRIP_TEMPLATE (decl))
 199           && DECL_DELETED_FN (decl))
 200         return 1;
 201       break;
 202
 203     case DW_AT_defaulted:
 204       if (TREE_CODE (decl) == FUNCTION_DECL
 205           && DECL_LANG_SPECIFIC (STRIP_TEMPLATE (decl))
 206           && DECL_DEFAULTED_FN (decl))
 207         {
 208           if (DECL_DEFAULTED_IN_CLASS_P (decl))
 209             return DW_DEFAULTED_in_class;
 210
 211           if (DECL_DEFAULTED_OUTSIDE_CLASS_P (decl))
 212             return DW_DEFAULTED_out_of_class;
 213         }
 214       break;
 215
 216     case DW_AT_const_expr:
 217       if (VAR_OR_FUNCTION_DECL_P (decl) && DECL_DECLARED_CONSTEXPR_P (decl))
 218         return 1;
 219       break;
 220
 221     case DW_AT_reference:
 222       if (TREE_CODE (decl) == FUNCTION_DECL
 223           && DECL_NONSTATIC_MEMBER_FUNCTION_P (decl)
 224           && FUNCTION_REF_QUALIFIED (TREE_TYPE (decl))
 225           && !FUNCTION_RVALUE_QUALIFIED (TREE_TYPE (decl)))
 226         return 1;
 227       break;
 228
 229     case DW_AT_rvalue_reference:
 230       if (TREE_CODE (decl) == FUNCTION_DECL
 231           && DECL_NONSTATIC_MEMBER_FUNCTION_P (decl)
 232           && FUNCTION_REF_QUALIFIED (TREE_TYPE (decl))
 233           && FUNCTION_RVALUE_QUALIFIED (TREE_TYPE (decl)))
 234         return 1;
 235       break;
 236
 237     case DW_AT_inline:
 238       if (VAR_P (decl) && DECL_INLINE_VAR_P (decl))
 239         {
 240           if (DECL_VAR_DECLARED_INLINE_P (decl))
 241             return DW_INL_declared_inlined;
 242           else
 243             return DW_INL_inlined;
 244         }
 245       break;
 246
 247     case DW_AT_export_symbols:
 248       if (TREE_CODE (decl) == NAMESPACE_DECL
 249           && (DECL_NAMESPACE_INLINE_P (decl)
 250               || (DECL_NAME (decl) == NULL_TREE && dwarf_version >= 5)))
 251         return 1;
 252       break;
 253
 254     default:
 255       break;
 256     }
 257
 258   return -1;
 259 }
 260
 261 /* Return -1 if dwarf ATTR shouldn't be added for TYPE, or the attribute
 262    value otherwise.  */
 263 int
 264 cp_type_dwarf_attribute (const_tree type, int attr)
 265 {
 266   if (type == NULL_TREE)
 267     return -1;
 268
 269   switch (attr)
 270     {
 271     case DW_AT_reference:
 272       if ((TREE_CODE (type) == FUNCTION_TYPE
 273            || TREE_CODE (type) == METHOD_TYPE)
 274           && FUNCTION_REF_QUALIFIED (type)
 275           && !FUNCTION_RVALUE_QUALIFIED (type))
 276         return 1;
 277       break;
 278
 279     case DW_AT_rvalue_reference:
 280       if ((TREE_CODE (type) == FUNCTION_TYPE
 281            || TREE_CODE (type) == METHOD_TYPE)
 282           && FUNCTION_REF_QUALIFIED (type)
 283           && FUNCTION_RVALUE_QUALIFIED (type))
 284         return 1;
 285       break;
 286
 287     default:
 288       break;
 289     }
 290
 291   return -1;
 292 }
 293
 294 /* Return the unit size of TYPE without reusable tail padding.  */
 295
 296 tree
 297 cp_unit_size_without_reusable_padding (tree type)
 298 {
 299   if (CLASS_TYPE_P (type))
 300     return CLASSTYPE_SIZE_UNIT (type);
 301   return TYPE_SIZE_UNIT (type);
 302 }
 303
 304 /* Stubs to keep c-opts.c happy.  */
 305 void
 306 push_file_scope (void)
 307 {
 308 }
 309
 310 void
 311 pop_file_scope (void)
 312 {
 313 }
 314
 315 /* c-pragma.c needs to query whether a decl has extern "C" linkage.  */
 316 bool
 317 has_c_linkage (const_tree decl)
 318 {
 319   return DECL_EXTERN_C_P (decl);
 320 }
 321
 322 static GTY ((cache))
 323      hash_table<tree_decl_map_cache_hasher> *shadowed_var_for_decl;
 324
 325 /* Lookup a shadowed var for FROM, and return it if we find one.  */
 326
 327 tree
 328 decl_shadowed_for_var_lookup (tree from)
 329 {
 330   struct tree_decl_map *h, in;
 331   in.base.from = from;
 332
 333   h = shadowed_var_for_decl->find_with_hash (&in, DECL_UID (from));
 334   if (h)
 335     return h->to;
 336   return NULL_TREE;
 337 }
 338
 339 /* Insert a mapping FROM->TO in the shadowed var hashtable.  */
 340
 341 void
 342 decl_shadowed_for_var_insert (tree from, tree to)
 343 {
 344   struct tree_decl_map *h;
 345
 346   h = ggc_alloc<tree_decl_map> ();
 347   h->base.from = from;
 348   h->to = to;
 349   *shadowed_var_for_decl->find_slot_with_hash (h, DECL_UID (from), INSERT) = h;
 350 }
 351
 352 void
 353 init_shadowed_var_for_decl (void)
 354 {
 355   shadowed_var_for_decl
 356     = hash_table<tree_decl_map_cache_hasher>::create_ggc (512);
 357 }
 358
 359 /* Return true if stmt can fall through.  Used by block_may_fallthru
 360    default case.  */
 361
 362 bool
 363 cxx_block_may_fallthru (const_tree stmt)
 364 {
 365   switch (TREE_CODE (stmt))
 366     {
 367     case EXPR_STMT:
 368       return block_may_fallthru (EXPR_STMT_EXPR (stmt));
 369
 370     case THROW_EXPR:
 371       return false;
 372
 373     default:
 374       return true;
 375     }
 376 }
 377
 378 /* Return the list of decls in the global namespace.  */
 379
 380 tree
 381 cp_get_global_decls ()
 382 {
 383   return NAMESPACE_LEVEL (global_namespace)->names;
 384 }
 385
 386 /* Push DECL into the current scope.  */
 387
 388 tree
 389 cp_pushdecl (tree decl)
 390 {
 391   return pushdecl (decl);
 392 }
 393
 394 /* Get the global value binding of NAME.  Called directly from
 395    c-common.c, not via a hook. */
 396
 397 tree
 398 identifier_global_value (tree name)
 399 {
 400   return get_global_binding (name);
 401 }
 402
 403 /* Register c++-specific dumps.  */
 404
 405 void
 406 cp_register_dumps (gcc::dump_manager *dumps)
 407 {
 408   class_dump_id = dumps->dump_register
 409     (".class", "lang-class", "lang-class", DK_lang, OPTGROUP_NONE, false);
 410
 411   raw_dump_id = dumps->dump_register
 412     (".raw", "lang-raw", "lang-raw", DK_lang, OPTGROUP_NONE, false);
 413 }
 414
 415 void
 416 cp_common_init_ts (void)
 417 {
 418   MARK_TS_DECL_NON_COMMON (USING_DECL);
 419   MARK_TS_DECL_COMMON (TEMPLATE_DECL);
 420   MARK_TS_DECL_COMMON (WILDCARD_DECL);
 421
 422   MARK_TS_COMMON (TEMPLATE_TEMPLATE_PARM);
 423   MARK_TS_COMMON (TEMPLATE_TYPE_PARM);
 424   MARK_TS_COMMON (TEMPLATE_PARM_INDEX);
 425   MARK_TS_COMMON (OVERLOAD);
 426   MARK_TS_COMMON (TEMPLATE_INFO);
 427   MARK_TS_COMMON (TYPENAME_TYPE);
 428   MARK_TS_COMMON (TYPEOF_TYPE);
 429   MARK_TS_COMMON (UNDERLYING_TYPE);
 430   MARK_TS_COMMON (BASELINK);
 431   MARK_TS_COMMON (TYPE_PACK_EXPANSION);
 432   MARK_TS_COMMON (TYPE_ARGUMENT_PACK);
 433   MARK_TS_COMMON (DECLTYPE_TYPE);
 434   MARK_TS_COMMON (BOUND_TEMPLATE_TEMPLATE_PARM);
 435   MARK_TS_COMMON (UNBOUND_CLASS_TEMPLATE);
 436
 437   MARK_TS_TYPED (EXPR_PACK_EXPANSION);
 438   MARK_TS_TYPED (SWITCH_STMT);
 439   MARK_TS_TYPED (IF_STMT);
 440   MARK_TS_TYPED (FOR_STMT);
 441   MARK_TS_TYPED (RANGE_FOR_STMT);
 442   MARK_TS_TYPED (AGGR_INIT_EXPR);
 443   MARK_TS_TYPED (EXPR_STMT);
 444   MARK_TS_TYPED (EH_SPEC_BLOCK);
 445   MARK_TS_TYPED (CLEANUP_STMT);
 446   MARK_TS_TYPED (SCOPE_REF);
 447   MARK_TS_TYPED (CAST_EXPR);
 448   MARK_TS_TYPED (NON_DEPENDENT_EXPR);
 449   MARK_TS_TYPED (MODOP_EXPR);
 450   MARK_TS_TYPED (TRY_BLOCK);
 451   MARK_TS_TYPED (THROW_EXPR);
 452   MARK_TS_TYPED (HANDLER);
 453   MARK_TS_TYPED (REINTERPRET_CAST_EXPR);
 454   MARK_TS_TYPED (CONST_CAST_EXPR);
 455   MARK_TS_TYPED (STATIC_CAST_EXPR);
 456   MARK_TS_TYPED (DYNAMIC_CAST_EXPR);
 457   MARK_TS_TYPED (IMPLICIT_CONV_EXPR);
 458   MARK_TS_TYPED (TEMPLATE_ID_EXPR);
 459   MARK_TS_TYPED (ARROW_EXPR);
 460   MARK_TS_TYPED (SIZEOF_EXPR);
 461   MARK_TS_TYPED (ALIGNOF_EXPR);
 462   MARK_TS_TYPED (AT_ENCODE_EXPR);
 463   MARK_TS_TYPED (UNARY_PLUS_EXPR);
 464   MARK_TS_TYPED (TRAIT_EXPR);
 465   MARK_TS_TYPED (TYPE_ARGUMENT_PACK);
 466   MARK_TS_TYPED (NOEXCEPT_EXPR);
 467   MARK_TS_TYPED (NONTYPE_ARGUMENT_PACK);
 468   MARK_TS_TYPED (WHILE_STMT);
 469   MARK_TS_TYPED (NEW_EXPR);
 470   MARK_TS_TYPED (VEC_NEW_EXPR);
 471   MARK_TS_TYPED (BREAK_STMT);
 472   MARK_TS_TYPED (MEMBER_REF);
 473   MARK_TS_TYPED (DOTSTAR_EXPR);
 474   MARK_TS_TYPED (DO_STMT);
 475   MARK_TS_TYPED (DELETE_EXPR);
 476   MARK_TS_TYPED (VEC_DELETE_EXPR);
 477   MARK_TS_TYPED (CONTINUE_STMT);
 478   MARK_TS_TYPED (TAG_DEFN);
 479   MARK_TS_TYPED (PSEUDO_DTOR_EXPR);
 480   MARK_TS_TYPED (TYPEID_EXPR);
 481   MARK_TS_TYPED (MUST_NOT_THROW_EXPR);
 482   MARK_TS_TYPED (STMT_EXPR);
 483   MARK_TS_TYPED (OFFSET_REF);
 484   MARK_TS_TYPED (OFFSETOF_EXPR);
 485   MARK_TS_TYPED (ADDRESSOF_EXPR);
 486   MARK_TS_TYPED (PTRMEM_CST);
 487   MARK_TS_TYPED (EMPTY_CLASS_EXPR);
 488   MARK_TS_TYPED (VEC_INIT_EXPR);
 489   MARK_TS_TYPED (USING_STMT);
 490   MARK_TS_TYPED (LAMBDA_EXPR);
 491   MARK_TS_TYPED (CTOR_INITIALIZER);
 492   MARK_TS_TYPED (ARRAY_NOTATION_REF);
 493   MARK_TS_TYPED (REQUIRES_EXPR);
 494   MARK_TS_TYPED (UNARY_LEFT_FOLD_EXPR);
 495   MARK_TS_TYPED (UNARY_RIGHT_FOLD_EXPR);
 496   MARK_TS_TYPED (BINARY_LEFT_FOLD_EXPR);
 497   MARK_TS_TYPED (BINARY_RIGHT_FOLD_EXPR);
 498 }
 499
 500 #include "gt-cp-cp-objcp-common.h"