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