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