gcc/cp/cp-lang.c

   1 /* Language-dependent hooks for C++.
   2    Copyright 2001 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 "tree.h"
  25 #include "cp-tree.h"
  26 #include "c-common.h"
  27 #include "toplev.h"
  28 #include "langhooks.h"
  29 #include "langhooks-def.h"
  30
  31 static HOST_WIDE_INT cxx_get_alias_set PARAMS ((tree));
  32 static bool ok_to_generate_alias_set_for_type PARAMS ((tree));
  33 static bool cxx_warn_unused_global_decl PARAMS ((tree));
  34
  35 #undef LANG_HOOKS_NAME
  36 #define LANG_HOOKS_NAME "GNU C++"
  37 #undef LANG_HOOKS_INIT
  38 #define LANG_HOOKS_INIT cxx_init
  39 #undef LANG_HOOKS_FINISH
  40 #define LANG_HOOKS_FINISH cxx_finish
  41 #undef LANG_HOOKS_CLEAR_BINDING_STACK
  42 #define LANG_HOOKS_CLEAR_BINDING_STACK pop_everything
  43 #undef LANG_HOOKS_INIT_OPTIONS
  44 #define LANG_HOOKS_INIT_OPTIONS cxx_init_options
  45 #undef LANG_HOOKS_DECODE_OPTION
  46 #define LANG_HOOKS_DECODE_OPTION cxx_decode_option
  47 #undef LANG_HOOKS_POST_OPTIONS
  48 #define LANG_HOOKS_POST_OPTIONS cxx_post_options
  49 #undef LANG_HOOKS_GET_ALIAS_SET
  50 #define LANG_HOOKS_GET_ALIAS_SET cxx_get_alias_set
  51 #undef LANG_HOOKS_EXPAND_CONSTANT
  52 #define LANG_HOOKS_EXPAND_CONSTANT cplus_expand_constant
  53 #undef LANG_HOOKS_EXPAND_EXPR
  54 #define LANG_HOOKS_EXPAND_EXPR cxx_expand_expr
  55 #undef LANG_HOOKS_SAFE_FROM_P
  56 #define LANG_HOOKS_SAFE_FROM_P c_safe_from_p
  57 #undef LANG_HOOKS_PARSE_FILE
  58 #define LANG_HOOKS_PARSE_FILE c_common_parse_file
  59 #undef LANG_HOOKS_DUP_LANG_SPECIFIC_DECL
  60 #define LANG_HOOKS_DUP_LANG_SPECIFIC_DECL cxx_dup_lang_specific_decl
  61 #undef LANG_HOOKS_UNSAVE_EXPR_NOW
  62 #define LANG_HOOKS_UNSAVE_EXPR_NOW cxx_unsave_expr_now
  63 #undef LANG_HOOKS_MAYBE_BUILD_CLEANUP
  64 #define LANG_HOOKS_MAYBE_BUILD_CLEANUP cxx_maybe_build_cleanup
  65 #undef LANG_HOOKS_TRUTHVALUE_CONVERSION
  66 #define LANG_HOOKS_TRUTHVALUE_CONVERSION c_common_truthvalue_conversion
  67 #undef LANG_HOOKS_INSERT_DEFAULT_ATTRIBUTES
  68 #define LANG_HOOKS_INSERT_DEFAULT_ATTRIBUTES cxx_insert_default_attributes
  69 #undef LANG_HOOKS_MARK_TREE
  70 #define LANG_HOOKS_MARK_TREE cxx_mark_tree
  71 #undef LANG_HOOKS_UNSAFE_FOR_REEVAL
  72 #define LANG_HOOKS_UNSAFE_FOR_REEVAL c_common_unsafe_for_reeval
  73 #undef LANG_HOOKS_SET_DECL_ASSEMBLER_NAME
  74 #define LANG_HOOKS_SET_DECL_ASSEMBLER_NAME mangle_decl
  75 #undef LANG_HOOKS_MARK_ADDRESSABLE
  76 #define LANG_HOOKS_MARK_ADDRESSABLE cxx_mark_addressable
  77 #undef LANG_HOOKS_PRINT_STATISTICS
  78 #define LANG_HOOKS_PRINT_STATISTICS cxx_print_statistics
  79 #undef LANG_HOOKS_PRINT_XNODE
  80 #define LANG_HOOKS_PRINT_XNODE cxx_print_xnode
  81 #undef LANG_HOOKS_PRINT_DECL
  82 #define LANG_HOOKS_PRINT_DECL cxx_print_decl
  83 #undef LANG_HOOKS_PRINT_TYPE
  84 #define LANG_HOOKS_PRINT_TYPE cxx_print_type
  85 #undef LANG_HOOKS_PRINT_IDENTIFIER
  86 #define LANG_HOOKS_PRINT_IDENTIFIER cxx_print_identifier
  87 #undef LANG_HOOKS_DECL_PRINTABLE_NAME
  88 #define LANG_HOOKS_DECL_PRINTABLE_NAME  cxx_printable_name
  89 #undef LANG_HOOKS_PRINT_ERROR_FUNCTION
  90 #define LANG_HOOKS_PRINT_ERROR_FUNCTION cxx_print_error_function
  91 #undef LANG_HOOKS_SET_YYDEBUG
  92 #define LANG_HOOKS_SET_YYDEBUG cxx_set_yydebug
  93 #undef LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL
  94 #define LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL cxx_warn_unused_global_decl
  95
  96 #undef LANG_HOOKS_TREE_INLINING_WALK_SUBTREES
  97 #define LANG_HOOKS_TREE_INLINING_WALK_SUBTREES \
  98   cp_walk_subtrees
  99 #undef LANG_HOOKS_TREE_INLINING_CANNOT_INLINE_TREE_FN
 100 #define LANG_HOOKS_TREE_INLINING_CANNOT_INLINE_TREE_FN \
 101   cp_cannot_inline_tree_fn
 102 #undef LANG_HOOKS_TREE_INLINING_ADD_PENDING_FN_DECLS
 103 #define LANG_HOOKS_TREE_INLINING_ADD_PENDING_FN_DECLS \
 104   cp_add_pending_fn_decls
 105 #undef LANG_HOOKS_TREE_INLINING_TREE_CHAIN_MATTERS_P
 106 #define LANG_HOOKS_TREE_INLINING_TREE_CHAIN_MATTERS_P \
 107   cp_is_overload_p
 108 #undef LANG_HOOKS_TREE_INLINING_AUTO_VAR_IN_FN_P
 109 #define LANG_HOOKS_TREE_INLINING_AUTO_VAR_IN_FN_P \
 110   cp_auto_var_in_fn_p
 111 #undef LANG_HOOKS_TREE_INLINING_COPY_RES_DECL_FOR_INLINING
 112 #define LANG_HOOKS_TREE_INLINING_COPY_RES_DECL_FOR_INLINING \
 113   cp_copy_res_decl_for_inlining
 114 #undef LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P
 115 #define LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P anon_aggr_type_p
 116 #undef LANG_HOOKS_TREE_INLINING_START_INLINING
 117 #define LANG_HOOKS_TREE_INLINING_START_INLINING cp_start_inlining
 118 #undef LANG_HOOKS_TREE_INLINING_END_INLINING
 119 #define LANG_HOOKS_TREE_INLINING_END_INLINING cp_end_inlining
 120 #undef LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN
 121 #define LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN cp_dump_tree
 122 #undef LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN
 123 #define LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN cp_type_quals
 124
 125 #undef LANG_HOOKS_MAKE_TYPE
 126 #define LANG_HOOKS_MAKE_TYPE cxx_make_type
 127 #undef LANG_HOOKS_TYPE_FOR_MODE
 128 #define LANG_HOOKS_TYPE_FOR_MODE c_common_type_for_mode
 129 #undef LANG_HOOKS_TYPE_FOR_SIZE
 130 #define LANG_HOOKS_TYPE_FOR_SIZE c_common_type_for_size
 131 #undef LANG_HOOKS_SIGNED_TYPE
 132 #define LANG_HOOKS_SIGNED_TYPE c_common_signed_type
 133 #undef LANG_HOOKS_UNSIGNED_TYPE
 134 #define LANG_HOOKS_UNSIGNED_TYPE c_common_unsigned_type
 135 #undef LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE
 136 #define LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE c_common_signed_or_unsigned_type
 137 #undef LANG_HOOKS_INCOMPLETE_TYPE_ERROR
 138 #define LANG_HOOKS_INCOMPLETE_TYPE_ERROR cxx_incomplete_type_error
 139 #undef LANG_HOOKS_TYPE_PROMOTES_TO
 140 #define LANG_HOOKS_TYPE_PROMOTES_TO cxx_type_promotes_to
 141
 142 /* Each front end provides its own hooks, for toplev.c.  */
 143 const struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 144
 145 /* Tree code classes. */
 146
 147 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
 148
 149 const char tree_code_type[] = {
 150 #include "tree.def"
 151   'x',
 152 #include "c-common.def"
 153   'x',
 154 #include "cp-tree.def"
 155 };
 156 #undef DEFTREECODE
 157
 158 /* Table indexed by tree code giving number of expression
 159    operands beyond the fixed part of the node structure.
 160    Not used for types or decls.  */
 161
 162 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
 163
 164 const unsigned char tree_code_length[] = {
 165 #include "tree.def"
 166   0,
 167 #include "c-common.def"
 168   0,
 169 #include "cp-tree.def"
 170 };
 171 #undef DEFTREECODE
 172
 173 /* Names of tree components.
 174    Used for printing out the tree and error messages.  */
 175 #define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,
 176
 177 const char *const tree_code_name[] = {
 178 #include "tree.def"
 179   "@@dummy",
 180 #include "c-common.def"
 181   "@@dummy",
 182 #include "cp-tree.def"
 183 };
 184 #undef DEFTREECODE
 185
 186 /* Check if a C++ type is safe for aliasing.
 187    Return TRUE if T safe for aliasing FALSE otherwise.  */
 188
 189 static bool
 190 ok_to_generate_alias_set_for_type (t)
 191      tree t;
 192 {
 193   if (TYPE_PTRMEMFUNC_P (t))
 194     return true;
 195   if (AGGREGATE_TYPE_P (t))
 196     {
 197       if ((TREE_CODE (t) == RECORD_TYPE) || (TREE_CODE (t) == UNION_TYPE))
 198         {
 199           tree fields;
 200           /* PODs are safe.  */
 201           if (! CLASSTYPE_NON_POD_P(t))
 202             return true;
 203           /* Classes with virtual baseclasses are not.  */
 204           if (TYPE_USES_VIRTUAL_BASECLASSES (t))
 205             return false;
 206           /* Recursively check the base classes.  */
 207           if (TYPE_BINFO (t) != NULL && TYPE_BINFO_BASETYPES (t) != NULL)
 208             {
 209               int i;
 210               for (i = 0; i < TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (t)); i++)
 211                 {
 212                   tree binfo = TREE_VEC_ELT (TYPE_BINFO_BASETYPES (t), i);
 213                   if (!ok_to_generate_alias_set_for_type (BINFO_TYPE (binfo)))
 214                     return false;
 215                 }
 216             }
 217           /* Check all the fields.  */
 218           for (fields = TYPE_FIELDS (t); fields; fields = TREE_CHAIN (fields))
 219             {
 220               if (TREE_CODE (fields) != FIELD_DECL)
 221                 continue;
 222               if (! ok_to_generate_alias_set_for_type (TREE_TYPE (fields)))
 223                 return false;
 224             }
 225           return true;
 226         }
 227       else if (TREE_CODE (t) == ARRAY_TYPE)
 228         return ok_to_generate_alias_set_for_type (TREE_TYPE (t));
 229       else
 230         /* This should never happen, we dealt with all the aggregate
 231            types that can appear in C++ above.  */
 232         abort ();
 233     }
 234   else
 235     return true;
 236 }
 237
 238 /* Special routine to get the alias set for C++.  */
 239
 240 static HOST_WIDE_INT
 241 cxx_get_alias_set (t)
 242      tree t;
 243 {
 244   /* It's not yet safe to use alias sets for classes in C++.  */
 245   if (!ok_to_generate_alias_set_for_type(t))
 246     return 0;
 247
 248   return c_common_get_alias_set (t);
 249 }
 250
 251 /* Called from check_global_declarations.  */
 252
 253 static bool
 254 cxx_warn_unused_global_decl (decl)
 255      tree decl;
 256 {
 257   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 258     return false;
 259   if (DECL_IN_SYSTEM_HEADER (decl))
 260     return false;
 261
 262   /* Const variables take the place of #defines in C++.  */
 263   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 264     return false;
 265
 266   return true;
 267 }