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 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 static tree cp_expr_size PARAMS ((tree));
  35
  36 #undef LANG_HOOKS_NAME
  37 #define LANG_HOOKS_NAME "GNU C++"
  38 #undef LANG_HOOKS_INIT
  39 #define LANG_HOOKS_INIT cxx_init
  40 #undef LANG_HOOKS_FINISH
  41 #define LANG_HOOKS_FINISH cxx_finish
  42 #undef LANG_HOOKS_CLEAR_BINDING_STACK
  43 #define LANG_HOOKS_CLEAR_BINDING_STACK pop_everything
  44 #undef LANG_HOOKS_INIT_OPTIONS
  45 #define LANG_HOOKS_INIT_OPTIONS cxx_init_options
  46 #undef LANG_HOOKS_DECODE_OPTION
  47 #define LANG_HOOKS_DECODE_OPTION c_common_decode_option
  48 #undef LANG_HOOKS_POST_OPTIONS
  49 #define LANG_HOOKS_POST_OPTIONS c_common_post_options
  50 #undef LANG_HOOKS_GET_ALIAS_SET
  51 #define LANG_HOOKS_GET_ALIAS_SET cxx_get_alias_set
  52 #undef LANG_HOOKS_EXPAND_CONSTANT
  53 #define LANG_HOOKS_EXPAND_CONSTANT cplus_expand_constant
  54 #undef LANG_HOOKS_EXPAND_EXPR
  55 #define LANG_HOOKS_EXPAND_EXPR cxx_expand_expr
  56 #undef LANG_HOOKS_SAFE_FROM_P
  57 #define LANG_HOOKS_SAFE_FROM_P c_safe_from_p
  58 #undef LANG_HOOKS_PARSE_FILE
  59 #define LANG_HOOKS_PARSE_FILE c_common_parse_file
  60 #undef LANG_HOOKS_DUP_LANG_SPECIFIC_DECL
  61 #define LANG_HOOKS_DUP_LANG_SPECIFIC_DECL cxx_dup_lang_specific_decl
  62 #undef LANG_HOOKS_UNSAVE_EXPR_NOW
  63 #define LANG_HOOKS_UNSAVE_EXPR_NOW cxx_unsave_expr_now
  64 #undef LANG_HOOKS_MAYBE_BUILD_CLEANUP
  65 #define LANG_HOOKS_MAYBE_BUILD_CLEANUP cxx_maybe_build_cleanup
  66 #undef LANG_HOOKS_TRUTHVALUE_CONVERSION
  67 #define LANG_HOOKS_TRUTHVALUE_CONVERSION c_common_truthvalue_conversion
  68 #undef LANG_HOOKS_INSERT_DEFAULT_ATTRIBUTES
  69 #define LANG_HOOKS_INSERT_DEFAULT_ATTRIBUTES cxx_insert_default_attributes
  70 #undef LANG_HOOKS_UNSAFE_FOR_REEVAL
  71 #define LANG_HOOKS_UNSAFE_FOR_REEVAL c_common_unsafe_for_reeval
  72 #undef LANG_HOOKS_SET_DECL_ASSEMBLER_NAME
  73 #define LANG_HOOKS_SET_DECL_ASSEMBLER_NAME mangle_decl
  74 #undef LANG_HOOKS_MARK_ADDRESSABLE
  75 #define LANG_HOOKS_MARK_ADDRESSABLE cxx_mark_addressable
  76 #undef LANG_HOOKS_PRINT_STATISTICS
  77 #define LANG_HOOKS_PRINT_STATISTICS cxx_print_statistics
  78 #undef LANG_HOOKS_PRINT_XNODE
  79 #define LANG_HOOKS_PRINT_XNODE cxx_print_xnode
  80 #undef LANG_HOOKS_PRINT_DECL
  81 #define LANG_HOOKS_PRINT_DECL cxx_print_decl
  82 #undef LANG_HOOKS_PRINT_TYPE
  83 #define LANG_HOOKS_PRINT_TYPE cxx_print_type
  84 #undef LANG_HOOKS_PRINT_IDENTIFIER
  85 #define LANG_HOOKS_PRINT_IDENTIFIER cxx_print_identifier
  86 #undef LANG_HOOKS_DECL_PRINTABLE_NAME
  87 #define LANG_HOOKS_DECL_PRINTABLE_NAME  cxx_printable_name
  88 #undef LANG_HOOKS_PRINT_ERROR_FUNCTION
  89 #define LANG_HOOKS_PRINT_ERROR_FUNCTION cxx_print_error_function
  90 #undef LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL
  91 #define LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL cxx_warn_unused_global_decl
  92
  93 #undef LANG_HOOKS_FUNCTION_INIT
  94 #define LANG_HOOKS_FUNCTION_INIT cxx_push_function_context
  95 #undef LANG_HOOKS_FUNCTION_FINAL
  96 #define LANG_HOOKS_FUNCTION_FINAL cxx_pop_function_context
  97
  98 /* Attribute hooks.  */
  99 #undef LANG_HOOKS_COMMON_ATTRIBUTE_TABLE
 100 #define LANG_HOOKS_COMMON_ATTRIBUTE_TABLE c_common_attribute_table
 101 #undef LANG_HOOKS_FORMAT_ATTRIBUTE_TABLE
 102 #define LANG_HOOKS_FORMAT_ATTRIBUTE_TABLE c_common_format_attribute_table
 103 #undef LANG_HOOKS_ATTRIBUTE_TABLE
 104 #define LANG_HOOKS_ATTRIBUTE_TABLE cxx_attribute_table
 105
 106 #undef LANG_HOOKS_TREE_INLINING_WALK_SUBTREES
 107 #define LANG_HOOKS_TREE_INLINING_WALK_SUBTREES \
 108   cp_walk_subtrees
 109 #undef LANG_HOOKS_TREE_INLINING_CANNOT_INLINE_TREE_FN
 110 #define LANG_HOOKS_TREE_INLINING_CANNOT_INLINE_TREE_FN \
 111   cp_cannot_inline_tree_fn
 112 #undef LANG_HOOKS_TREE_INLINING_ADD_PENDING_FN_DECLS
 113 #define LANG_HOOKS_TREE_INLINING_ADD_PENDING_FN_DECLS \
 114   cp_add_pending_fn_decls
 115 #undef LANG_HOOKS_TREE_INLINING_TREE_CHAIN_MATTERS_P
 116 #define LANG_HOOKS_TREE_INLINING_TREE_CHAIN_MATTERS_P \
 117   cp_is_overload_p
 118 #undef LANG_HOOKS_TREE_INLINING_AUTO_VAR_IN_FN_P
 119 #define LANG_HOOKS_TREE_INLINING_AUTO_VAR_IN_FN_P \
 120   cp_auto_var_in_fn_p
 121 #undef LANG_HOOKS_TREE_INLINING_COPY_RES_DECL_FOR_INLINING
 122 #define LANG_HOOKS_TREE_INLINING_COPY_RES_DECL_FOR_INLINING \
 123   cp_copy_res_decl_for_inlining
 124 #undef LANG_HOOKS_TREE_INLINING_CONVERT_PARM_FOR_INLINING
 125 #define LANG_HOOKS_TREE_INLINING_CONVERT_PARM_FOR_INLINING \
 126   cp_convert_parm_for_inlining
 127 #undef LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P
 128 #define LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P anon_aggr_type_p
 129 #undef LANG_HOOKS_TREE_INLINING_START_INLINING
 130 #define LANG_HOOKS_TREE_INLINING_START_INLINING cp_start_inlining
 131 #undef LANG_HOOKS_TREE_INLINING_END_INLINING
 132 #define LANG_HOOKS_TREE_INLINING_END_INLINING cp_end_inlining
 133 #undef LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN
 134 #define LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN cp_dump_tree
 135 #undef LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN
 136 #define LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN cp_type_quals
 137 #undef LANG_HOOKS_EXPR_SIZE
 138 #define LANG_HOOKS_EXPR_SIZE cp_expr_size
 139
 140 #undef LANG_HOOKS_MAKE_TYPE
 141 #define LANG_HOOKS_MAKE_TYPE cxx_make_type
 142 #undef LANG_HOOKS_TYPE_FOR_MODE
 143 #define LANG_HOOKS_TYPE_FOR_MODE c_common_type_for_mode
 144 #undef LANG_HOOKS_TYPE_FOR_SIZE
 145 #define LANG_HOOKS_TYPE_FOR_SIZE c_common_type_for_size
 146 #undef LANG_HOOKS_SIGNED_TYPE
 147 #define LANG_HOOKS_SIGNED_TYPE c_common_signed_type
 148 #undef LANG_HOOKS_UNSIGNED_TYPE
 149 #define LANG_HOOKS_UNSIGNED_TYPE c_common_unsigned_type
 150 #undef LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE
 151 #define LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE c_common_signed_or_unsigned_type
 152 #undef LANG_HOOKS_INCOMPLETE_TYPE_ERROR
 153 #define LANG_HOOKS_INCOMPLETE_TYPE_ERROR cxx_incomplete_type_error
 154 #undef LANG_HOOKS_TYPE_PROMOTES_TO
 155 #define LANG_HOOKS_TYPE_PROMOTES_TO cxx_type_promotes_to
 156
 157 /* Each front end provides its own hooks, for toplev.c.  */
 158 const struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 159
 160 /* Tree code classes. */
 161
 162 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
 163
 164 const char tree_code_type[] = {
 165 #include "tree.def"
 166   'x',
 167 #include "c-common.def"
 168   'x',
 169 #include "cp-tree.def"
 170 };
 171 #undef DEFTREECODE
 172
 173 /* Table indexed by tree code giving number of expression
 174    operands beyond the fixed part of the node structure.
 175    Not used for types or decls.  */
 176
 177 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
 178
 179 const unsigned char tree_code_length[] = {
 180 #include "tree.def"
 181   0,
 182 #include "c-common.def"
 183   0,
 184 #include "cp-tree.def"
 185 };
 186 #undef DEFTREECODE
 187
 188 /* Names of tree components.
 189    Used for printing out the tree and error messages.  */
 190 #define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,
 191
 192 const char *const tree_code_name[] = {
 193 #include "tree.def"
 194   "@@dummy",
 195 #include "c-common.def"
 196   "@@dummy",
 197 #include "cp-tree.def"
 198 };
 199 #undef DEFTREECODE
 200
 201 /* Check if a C++ type is safe for aliasing.
 202    Return TRUE if T safe for aliasing FALSE otherwise.  */
 203
 204 static bool
 205 ok_to_generate_alias_set_for_type (t)
 206      tree t;
 207 {
 208   if (TYPE_PTRMEMFUNC_P (t))
 209     return true;
 210   if (AGGREGATE_TYPE_P (t))
 211     {
 212       if ((TREE_CODE (t) == RECORD_TYPE) || (TREE_CODE (t) == UNION_TYPE))
 213         {
 214           tree fields;
 215           /* Backend-created structs are safe.  */
 216           if (! CLASS_TYPE_P (t))
 217             return true;
 218           /* PODs are safe.  */
 219           if (! CLASSTYPE_NON_POD_P(t))
 220             return true;
 221           /* Classes with virtual baseclasses are not.  */
 222           if (TYPE_USES_VIRTUAL_BASECLASSES (t))
 223             return false;
 224           /* Recursively check the base classes.  */
 225           if (TYPE_BINFO (t) != NULL && TYPE_BINFO_BASETYPES (t) != NULL)
 226             {
 227               int i;
 228               for (i = 0; i < TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (t)); i++)
 229                 {
 230                   tree binfo = TREE_VEC_ELT (TYPE_BINFO_BASETYPES (t), i);
 231                   if (!ok_to_generate_alias_set_for_type (BINFO_TYPE (binfo)))
 232                     return false;
 233                 }
 234             }
 235           /* Check all the fields.  */
 236           for (fields = TYPE_FIELDS (t); fields; fields = TREE_CHAIN (fields))
 237             {
 238               if (TREE_CODE (fields) != FIELD_DECL)
 239                 continue;
 240               if (! ok_to_generate_alias_set_for_type (TREE_TYPE (fields)))
 241                 return false;
 242             }
 243           return true;
 244         }
 245       else if (TREE_CODE (t) == ARRAY_TYPE)
 246         return ok_to_generate_alias_set_for_type (TREE_TYPE (t));
 247       else
 248         /* This should never happen, we dealt with all the aggregate
 249            types that can appear in C++ above.  */
 250         abort ();
 251     }
 252   else
 253     return true;
 254 }
 255
 256 /* Special routine to get the alias set for C++.  */
 257
 258 static HOST_WIDE_INT
 259 cxx_get_alias_set (t)
 260      tree t;
 261 {
 262   /* It's not yet safe to use alias sets for classes in C++.  */
 263   if (!ok_to_generate_alias_set_for_type(t))
 264     return 0;
 265
 266   return c_common_get_alias_set (t);
 267 }
 268
 269 /* Called from check_global_declarations.  */
 270
 271 static bool
 272 cxx_warn_unused_global_decl (decl)
 273      tree decl;
 274 {
 275   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 276     return false;
 277   if (DECL_IN_SYSTEM_HEADER (decl))
 278     return false;
 279
 280   /* Const variables take the place of #defines in C++.  */
 281   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 282     return false;
 283
 284   return true;
 285 }
 286
 287 /* Langhook for expr_size: Tell the backend that the value of an expression
 288    of non-POD class type does not include any tail padding; a derived class
 289    might have allocated something there.  */
 290
 291 static tree
 292 cp_expr_size (exp)
 293      tree exp;
 294 {
 295   if (CLASS_TYPE_P (TREE_TYPE (exp)))
 296     {
 297       /* The backend should not be interested in the size of an expression
 298          of a type with both of these set; all copies of such types must go
 299          through a constructor or assignment op.  */
 300       if (TYPE_HAS_COMPLEX_INIT_REF (TREE_TYPE (exp))
 301           && TYPE_HAS_COMPLEX_ASSIGN_REF (TREE_TYPE (exp))
 302           /* But storing a CONSTRUCTOR isn't a copy.  */
 303           && TREE_CODE (exp) != CONSTRUCTOR)
 304         abort ();
 305       /* This would be wrong for a type with virtual bases, but they are
 306          caught by the abort above.  */
 307       return CLASSTYPE_SIZE_UNIT (TREE_TYPE (exp));
 308     }
 309   else
 310     /* Use the default code.  */
 311     return lhd_expr_size (exp);
 312 }