gcc/cp/cp-lang.c

   1 /* Language-dependent hooks for C++.
   2    Copyright 2001, 2002 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 "tree.h"
  27 #include "cp-tree.h"
  28 #include "c-common.h"
  29 #include "toplev.h"
  30 #include "langhooks.h"
  31 #include "langhooks-def.h"
  32 #include "diagnostic.h"
  33 #include "cxx-pretty-print.h"
  34
  35 enum c_language_kind c_language = clk_cxx;
  36
  37 static HOST_WIDE_INT cxx_get_alias_set (tree);
  38 static bool ok_to_generate_alias_set_for_type (tree);
  39 static bool cxx_warn_unused_global_decl (tree);
  40 static tree cp_expr_size (tree);
  41 static size_t cp_tree_size (enum tree_code);
  42 static bool cp_var_mod_type_p (tree);
  43 static void cxx_initialize_diagnostics (diagnostic_context *);
  44
  45 #undef LANG_HOOKS_NAME
  46 #define LANG_HOOKS_NAME "GNU C++"
  47 #undef LANG_HOOKS_TREE_SIZE
  48 #define LANG_HOOKS_TREE_SIZE cp_tree_size
  49 #undef LANG_HOOKS_INIT
  50 #define LANG_HOOKS_INIT cxx_init
  51 #undef LANG_HOOKS_FINISH
  52 #define LANG_HOOKS_FINISH cxx_finish
  53 #undef LANG_HOOKS_CLEAR_BINDING_STACK
  54 #define LANG_HOOKS_CLEAR_BINDING_STACK pop_everything
  55 #undef LANG_HOOKS_INIT_OPTIONS
  56 #define LANG_HOOKS_INIT_OPTIONS c_common_init_options
  57 #undef LANG_HOOKS_INITIALIZE_DIAGNOSTICS
  58 #define LANG_HOOKS_INITIALIZE_DIAGNOSTICS cxx_initialize_diagnostics
  59 #undef LANG_HOOKS_HANDLE_OPTION
  60 #define LANG_HOOKS_HANDLE_OPTION c_common_handle_option
  61 #undef LANG_HOOKS_HANDLE_FILENAME
  62 #define LANG_HOOKS_HANDLE_FILENAME c_common_handle_filename
  63 #undef LANG_HOOKS_MISSING_ARGUMENT
  64 #define LANG_HOOKS_MISSING_ARGUMENT c_common_missing_argument
  65 #undef LANG_HOOKS_POST_OPTIONS
  66 #define LANG_HOOKS_POST_OPTIONS c_common_post_options
  67 #undef LANG_HOOKS_GET_ALIAS_SET
  68 #define LANG_HOOKS_GET_ALIAS_SET cxx_get_alias_set
  69 #undef LANG_HOOKS_EXPAND_CONSTANT
  70 #define LANG_HOOKS_EXPAND_CONSTANT cplus_expand_constant
  71 #undef LANG_HOOKS_EXPAND_EXPR
  72 #define LANG_HOOKS_EXPAND_EXPR cxx_expand_expr
  73 #undef LANG_HOOKS_SAFE_FROM_P
  74 #define LANG_HOOKS_SAFE_FROM_P c_safe_from_p
  75 #undef LANG_HOOKS_PARSE_FILE
  76 #define LANG_HOOKS_PARSE_FILE c_common_parse_file
  77 #undef LANG_HOOKS_DUP_LANG_SPECIFIC_DECL
  78 #define LANG_HOOKS_DUP_LANG_SPECIFIC_DECL cxx_dup_lang_specific_decl
  79 #undef LANG_HOOKS_UNSAVE_EXPR_NOW
  80 #define LANG_HOOKS_UNSAVE_EXPR_NOW cxx_unsave_expr_now
  81 #undef LANG_HOOKS_MAYBE_BUILD_CLEANUP
  82 #define LANG_HOOKS_MAYBE_BUILD_CLEANUP cxx_maybe_build_cleanup
  83 #undef LANG_HOOKS_TRUTHVALUE_CONVERSION
  84 #define LANG_HOOKS_TRUTHVALUE_CONVERSION c_common_truthvalue_conversion
  85 #undef LANG_HOOKS_UNSAFE_FOR_REEVAL
  86 #define LANG_HOOKS_UNSAFE_FOR_REEVAL c_common_unsafe_for_reeval
  87 #undef LANG_HOOKS_SET_DECL_ASSEMBLER_NAME
  88 #define LANG_HOOKS_SET_DECL_ASSEMBLER_NAME mangle_decl
  89 #undef LANG_HOOKS_MARK_ADDRESSABLE
  90 #define LANG_HOOKS_MARK_ADDRESSABLE cxx_mark_addressable
  91 #undef LANG_HOOKS_PRINT_STATISTICS
  92 #define LANG_HOOKS_PRINT_STATISTICS cxx_print_statistics
  93 #undef LANG_HOOKS_PRINT_XNODE
  94 #define LANG_HOOKS_PRINT_XNODE cxx_print_xnode
  95 #undef LANG_HOOKS_PRINT_DECL
  96 #define LANG_HOOKS_PRINT_DECL cxx_print_decl
  97 #undef LANG_HOOKS_PRINT_TYPE
  98 #define LANG_HOOKS_PRINT_TYPE cxx_print_type
  99 #undef LANG_HOOKS_PRINT_IDENTIFIER
 100 #define LANG_HOOKS_PRINT_IDENTIFIER cxx_print_identifier
 101 #undef LANG_HOOKS_DECL_PRINTABLE_NAME
 102 #define LANG_HOOKS_DECL_PRINTABLE_NAME  cxx_printable_name
 103 #undef LANG_HOOKS_PRINT_ERROR_FUNCTION
 104 #define LANG_HOOKS_PRINT_ERROR_FUNCTION cxx_print_error_function
 105 #undef LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL
 106 #define LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL cxx_warn_unused_global_decl
 107 #undef LANG_HOOKS_WRITE_GLOBALS
 108 #define LANG_HOOKS_WRITE_GLOBALS lhd_do_nothing
 109 #undef LANG_HOOKS_DECL_UNINIT
 110 #define LANG_HOOKS_DECL_UNINIT c_decl_uninit
 111
 112
 113 #undef LANG_HOOKS_FUNCTION_INIT
 114 #define LANG_HOOKS_FUNCTION_INIT cxx_push_function_context
 115 #undef LANG_HOOKS_FUNCTION_FINAL
 116 #define LANG_HOOKS_FUNCTION_FINAL cxx_pop_function_context
 117
 118 #undef LANG_HOOKS_RTL_EXPAND_START
 119 #define LANG_HOOKS_RTL_EXPAND_START cxx_expand_function_start
 120 #undef LANG_HOOKS_RTL_EXPAND_STMT
 121 #define LANG_HOOKS_RTL_EXPAND_STMT expand_stmt
 122
 123 /* Attribute hooks.  */
 124 #undef LANG_HOOKS_COMMON_ATTRIBUTE_TABLE
 125 #define LANG_HOOKS_COMMON_ATTRIBUTE_TABLE c_common_attribute_table
 126 #undef LANG_HOOKS_FORMAT_ATTRIBUTE_TABLE
 127 #define LANG_HOOKS_FORMAT_ATTRIBUTE_TABLE c_common_format_attribute_table
 128 #undef LANG_HOOKS_ATTRIBUTE_TABLE
 129 #define LANG_HOOKS_ATTRIBUTE_TABLE cxx_attribute_table
 130
 131 #undef LANG_HOOKS_TREE_INLINING_WALK_SUBTREES
 132 #define LANG_HOOKS_TREE_INLINING_WALK_SUBTREES \
 133   cp_walk_subtrees
 134 #undef LANG_HOOKS_TREE_INLINING_CANNOT_INLINE_TREE_FN
 135 #define LANG_HOOKS_TREE_INLINING_CANNOT_INLINE_TREE_FN \
 136   cp_cannot_inline_tree_fn
 137 #undef LANG_HOOKS_TREE_INLINING_ADD_PENDING_FN_DECLS
 138 #define LANG_HOOKS_TREE_INLINING_ADD_PENDING_FN_DECLS \
 139   cp_add_pending_fn_decls
 140 #undef LANG_HOOKS_TREE_INLINING_TREE_CHAIN_MATTERS_P
 141 #define LANG_HOOKS_TREE_INLINING_TREE_CHAIN_MATTERS_P \
 142   cp_is_overload_p
 143 #undef LANG_HOOKS_TREE_INLINING_AUTO_VAR_IN_FN_P
 144 #define LANG_HOOKS_TREE_INLINING_AUTO_VAR_IN_FN_P \
 145   cp_auto_var_in_fn_p
 146 #undef LANG_HOOKS_TREE_INLINING_COPY_RES_DECL_FOR_INLINING
 147 #define LANG_HOOKS_TREE_INLINING_COPY_RES_DECL_FOR_INLINING \
 148   cp_copy_res_decl_for_inlining
 149 #undef LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P
 150 #define LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P anon_aggr_type_p
 151 #undef LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P
 152 #define LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P cp_var_mod_type_p
 153 #undef LANG_HOOKS_TREE_INLINING_START_INLINING
 154 #define LANG_HOOKS_TREE_INLINING_START_INLINING cp_start_inlining
 155 #undef LANG_HOOKS_TREE_INLINING_END_INLINING
 156 #define LANG_HOOKS_TREE_INLINING_END_INLINING cp_end_inlining
 157 #undef LANG_HOOKS_TREE_INLINING_ESTIMATE_NUM_INSNS
 158 #define LANG_HOOKS_TREE_INLINING_ESTIMATE_NUM_INSNS c_estimate_num_insns
 159 #undef LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN
 160 #define LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN cp_dump_tree
 161 #undef LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN
 162 #define LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN cp_type_quals
 163 #undef LANG_HOOKS_EXPR_SIZE
 164 #define LANG_HOOKS_EXPR_SIZE cp_expr_size
 165
 166 #undef LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION
 167 #define LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION expand_body
 168 #undef LANG_HOOKS_CALLGRAPH_LOWER_FUNCTION
 169 #define LANG_HOOKS_CALLGRAPH_LOWER_FUNCTION lower_function
 170
 171 #undef LANG_HOOKS_MAKE_TYPE
 172 #define LANG_HOOKS_MAKE_TYPE cxx_make_type
 173 #undef LANG_HOOKS_TYPE_FOR_MODE
 174 #define LANG_HOOKS_TYPE_FOR_MODE c_common_type_for_mode
 175 #undef LANG_HOOKS_TYPE_FOR_SIZE
 176 #define LANG_HOOKS_TYPE_FOR_SIZE c_common_type_for_size
 177 #undef LANG_HOOKS_SIGNED_TYPE
 178 #define LANG_HOOKS_SIGNED_TYPE c_common_signed_type
 179 #undef LANG_HOOKS_UNSIGNED_TYPE
 180 #define LANG_HOOKS_UNSIGNED_TYPE c_common_unsigned_type
 181 #undef LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE
 182 #define LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE c_common_signed_or_unsigned_type
 183 #undef LANG_HOOKS_INCOMPLETE_TYPE_ERROR
 184 #define LANG_HOOKS_INCOMPLETE_TYPE_ERROR cxx_incomplete_type_error
 185 #undef LANG_HOOKS_TYPE_PROMOTES_TO
 186 #define LANG_HOOKS_TYPE_PROMOTES_TO cxx_type_promotes_to
 187
 188 /* Each front end provides its own hooks, for toplev.c.  */
 189 const struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 190
 191 /* Tree code classes.  */
 192
 193 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
 194
 195 const char tree_code_type[] = {
 196 #include "tree.def"
 197   'x',
 198 #include "c-common.def"
 199   'x',
 200 #include "cp-tree.def"
 201 };
 202 #undef DEFTREECODE
 203
 204 /* Table indexed by tree code giving number of expression
 205    operands beyond the fixed part of the node structure.
 206    Not used for types or decls.  */
 207
 208 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
 209
 210 const unsigned char tree_code_length[] = {
 211 #include "tree.def"
 212   0,
 213 #include "c-common.def"
 214   0,
 215 #include "cp-tree.def"
 216 };
 217 #undef DEFTREECODE
 218
 219 /* Names of tree components.
 220    Used for printing out the tree and error messages.  */
 221 #define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,
 222
 223 const char *const tree_code_name[] = {
 224 #include "tree.def"
 225   "@@dummy",
 226 #include "c-common.def"
 227   "@@dummy",
 228 #include "cp-tree.def"
 229 };
 230 #undef DEFTREECODE
 231
 232 /* Check if a C++ type is safe for aliasing.
 233    Return TRUE if T safe for aliasing FALSE otherwise.  */
 234
 235 static bool
 236 ok_to_generate_alias_set_for_type (tree t)
 237 {
 238   if (TYPE_PTRMEMFUNC_P (t))
 239     return true;
 240   if (AGGREGATE_TYPE_P (t))
 241     {
 242       if ((TREE_CODE (t) == RECORD_TYPE) || (TREE_CODE (t) == UNION_TYPE))
 243         {
 244           tree fields;
 245           /* Backend-created structs are safe.  */
 246           if (! CLASS_TYPE_P (t))
 247             return true;
 248           /* PODs are safe.  */
 249           if (! CLASSTYPE_NON_POD_P(t))
 250             return true;
 251           /* Classes with virtual baseclasses are not.  */
 252           if (TYPE_USES_VIRTUAL_BASECLASSES (t))
 253             return false;
 254           /* Recursively check the base classes.  */
 255           if (TYPE_BINFO (t) != NULL && TYPE_BINFO_BASETYPES (t) != NULL)
 256             {
 257               int i;
 258               for (i = 0; i < TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (t)); i++)
 259                 {
 260                   tree binfo = TREE_VEC_ELT (TYPE_BINFO_BASETYPES (t), i);
 261                   if (!ok_to_generate_alias_set_for_type (BINFO_TYPE (binfo)))
 262                     return false;
 263                 }
 264             }
 265           /* Check all the fields.  */
 266           for (fields = TYPE_FIELDS (t); fields; fields = TREE_CHAIN (fields))
 267             {
 268               if (TREE_CODE (fields) != FIELD_DECL)
 269                 continue;
 270               if (! ok_to_generate_alias_set_for_type (TREE_TYPE (fields)))
 271                 return false;
 272             }
 273           return true;
 274         }
 275       else if (TREE_CODE (t) == ARRAY_TYPE)
 276         return ok_to_generate_alias_set_for_type (TREE_TYPE (t));
 277       else
 278         /* This should never happen, we dealt with all the aggregate
 279            types that can appear in C++ above.  */
 280         abort ();
 281     }
 282   else
 283     return true;
 284 }
 285
 286 /* Special routine to get the alias set for C++.  */
 287
 288 static HOST_WIDE_INT
 289 cxx_get_alias_set (tree t)
 290 {
 291
 292   if (/* It's not yet safe to use alias sets for some classes in C++.  */
 293       !ok_to_generate_alias_set_for_type (t)
 294       /* Nor is it safe to use alias sets for pointers-to-member
 295          functions, due to the fact that there may be more than one
 296          RECORD_TYPE type corresponding to the same pointer-to-member
 297          type.  */
 298       || TYPE_PTRMEMFUNC_P (t))
 299     return 0;
 300
 301   return c_common_get_alias_set (t);
 302 }
 303
 304 /* Called from check_global_declarations.  */
 305
 306 static bool
 307 cxx_warn_unused_global_decl (tree decl)
 308 {
 309   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 310     return false;
 311   if (DECL_IN_SYSTEM_HEADER (decl))
 312     return false;
 313
 314   /* Const variables take the place of #defines in C++.  */
 315   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 316     return false;
 317
 318   return true;
 319 }
 320
 321 /* Langhook for expr_size: Tell the backend that the value of an expression
 322    of non-POD class type does not include any tail padding; a derived class
 323    might have allocated something there.  */
 324
 325 static tree
 326 cp_expr_size (tree exp)
 327 {
 328   if (CLASS_TYPE_P (TREE_TYPE (exp)))
 329     {
 330       /* The backend should not be interested in the size of an expression
 331          of a type with both of these set; all copies of such types must go
 332          through a constructor or assignment op.  */
 333       if (TYPE_HAS_COMPLEX_INIT_REF (TREE_TYPE (exp))
 334           && TYPE_HAS_COMPLEX_ASSIGN_REF (TREE_TYPE (exp))
 335           /* But storing a CONSTRUCTOR isn't a copy.  */
 336           && TREE_CODE (exp) != CONSTRUCTOR)
 337         abort ();
 338       /* This would be wrong for a type with virtual bases, but they are
 339          caught by the abort above.  */
 340       return CLASSTYPE_SIZE_UNIT (TREE_TYPE (exp));
 341     }
 342   else
 343     /* Use the default code.  */
 344     return lhd_expr_size (exp);
 345 }
 346
 347 /* Langhook for tree_size: determine size of our 'x' and 'c' nodes.  */
 348 static size_t
 349 cp_tree_size (enum tree_code code)
 350 {
 351   switch (code)
 352     {
 353     case PTRMEM_CST:            return sizeof (struct ptrmem_cst);
 354     case BASELINK:              return sizeof (struct tree_baselink);
 355     case TEMPLATE_PARM_INDEX:   return sizeof (template_parm_index);
 356     case DEFAULT_ARG:           return sizeof (struct tree_default_arg);
 357     case OVERLOAD:              return sizeof (struct tree_overload);
 358     case WRAPPER:               return sizeof (struct tree_wrapper);
 359     default:
 360       abort ();
 361     }
 362   /* NOTREACHED */
 363 }
 364
 365 /* Returns true if T is a variably modified type, in the sense of C99.
 366    This routine needs only check cases that cannot be handled by the
 367    language-independent logic in tree-inline.c.  */
 368
 369 static bool
 370 cp_var_mod_type_p (tree type)
 371 {
 372   /* If TYPE is a pointer-to-member, it is variably modified if either
 373      the class or the member are variably modified.  */
 374   if (TYPE_PTR_TO_MEMBER_P (type))
 375     return (variably_modified_type_p (TYPE_PTRMEM_CLASS_TYPE (type))
 376             || variably_modified_type_p (TYPE_PTRMEM_POINTED_TO_TYPE (type)));
 377
 378   /* All other types are not variably modified.  */
 379   return false;
 380 }
 381
 382 /* Stub routine to tell people that this doesn't work yet.  */
 383 void
 384 c_reset_state (void)
 385 {
 386   sorry ("inter-module optimisations not implemented yet");
 387 }
 388
 389 /* Construct a C++-aware pretty-printer for CONTEXT.  It is assumed
 390    that CONTEXT->printer is an already constructed basic pretty_printer.  */
 391 static void
 392 cxx_initialize_diagnostics (diagnostic_context *context)
 393 {
 394   pretty_printer *base = context->printer;
 395   cxx_pretty_printer *pp = xmalloc (sizeof (cxx_pretty_printer));
 396   memcpy (pp_base (pp), base, sizeof (pretty_printer));
 397   pp_cxx_pretty_printer_init (pp);
 398   context->printer = (pretty_printer *) pp;
 399
 400   /* It is safe to free this object because it was previously malloc()'d.  */
 401   free (base);
 402 }