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_BUILTIN_TYPE_DECLS
 106 #define LANG_HOOKS_BUILTIN_TYPE_DECLS cxx_builtin_type_decls
 107 #undef LANG_HOOKS_PUSHLEVEL
 108 #define LANG_HOOKS_PUSHLEVEL lhd_do_nothing_i
 109 #undef LANG_HOOKS_POPLEVEL
 110 #define LANG_HOOKS_POPLEVEL lhd_do_nothing_iii_return_null_tree
 111 #undef LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL
 112 #define LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL cxx_warn_unused_global_decl
 113 #undef LANG_HOOKS_WRITE_GLOBALS
 114 #define LANG_HOOKS_WRITE_GLOBALS lhd_do_nothing
 115 #undef LANG_HOOKS_DECL_UNINIT
 116 #define LANG_HOOKS_DECL_UNINIT c_decl_uninit
 117
 118
 119 #undef LANG_HOOKS_FUNCTION_INIT
 120 #define LANG_HOOKS_FUNCTION_INIT cxx_push_function_context
 121 #undef LANG_HOOKS_FUNCTION_FINAL
 122 #define LANG_HOOKS_FUNCTION_FINAL cxx_pop_function_context
 123
 124 #undef LANG_HOOKS_RTL_EXPAND_START
 125 #define LANG_HOOKS_RTL_EXPAND_START cxx_expand_function_start
 126 #undef LANG_HOOKS_RTL_EXPAND_STMT
 127 #define LANG_HOOKS_RTL_EXPAND_STMT expand_stmt
 128
 129 /* Attribute hooks.  */
 130 #undef LANG_HOOKS_COMMON_ATTRIBUTE_TABLE
 131 #define LANG_HOOKS_COMMON_ATTRIBUTE_TABLE c_common_attribute_table
 132 #undef LANG_HOOKS_FORMAT_ATTRIBUTE_TABLE
 133 #define LANG_HOOKS_FORMAT_ATTRIBUTE_TABLE c_common_format_attribute_table
 134 #undef LANG_HOOKS_ATTRIBUTE_TABLE
 135 #define LANG_HOOKS_ATTRIBUTE_TABLE cxx_attribute_table
 136
 137 #undef LANG_HOOKS_TREE_INLINING_WALK_SUBTREES
 138 #define LANG_HOOKS_TREE_INLINING_WALK_SUBTREES \
 139   cp_walk_subtrees
 140 #undef LANG_HOOKS_TREE_INLINING_CANNOT_INLINE_TREE_FN
 141 #define LANG_HOOKS_TREE_INLINING_CANNOT_INLINE_TREE_FN \
 142   cp_cannot_inline_tree_fn
 143 #undef LANG_HOOKS_TREE_INLINING_ADD_PENDING_FN_DECLS
 144 #define LANG_HOOKS_TREE_INLINING_ADD_PENDING_FN_DECLS \
 145   cp_add_pending_fn_decls
 146 #undef LANG_HOOKS_TREE_INLINING_TREE_CHAIN_MATTERS_P
 147 #define LANG_HOOKS_TREE_INLINING_TREE_CHAIN_MATTERS_P \
 148   cp_is_overload_p
 149 #undef LANG_HOOKS_TREE_INLINING_AUTO_VAR_IN_FN_P
 150 #define LANG_HOOKS_TREE_INLINING_AUTO_VAR_IN_FN_P \
 151   cp_auto_var_in_fn_p
 152 #undef LANG_HOOKS_TREE_INLINING_COPY_RES_DECL_FOR_INLINING
 153 #define LANG_HOOKS_TREE_INLINING_COPY_RES_DECL_FOR_INLINING \
 154   cp_copy_res_decl_for_inlining
 155 #undef LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P
 156 #define LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P anon_aggr_type_p
 157 #undef LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P
 158 #define LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P cp_var_mod_type_p
 159 #undef LANG_HOOKS_TREE_INLINING_ESTIMATE_NUM_INSNS
 160 #define LANG_HOOKS_TREE_INLINING_ESTIMATE_NUM_INSNS c_estimate_num_insns
 161 #undef LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN
 162 #define LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN cp_dump_tree
 163 #undef LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN
 164 #define LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN cp_type_quals
 165 #undef LANG_HOOKS_EXPR_SIZE
 166 #define LANG_HOOKS_EXPR_SIZE cp_expr_size
 167
 168 #undef LANG_HOOKS_CALLGRAPH_ANALYZE_EXPR
 169 #define LANG_HOOKS_CALLGRAPH_ANALYZE_EXPR cxx_callgraph_analyze_expr
 170 #undef LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION
 171 #define LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION expand_body
 172
 173 #undef LANG_HOOKS_MAKE_TYPE
 174 #define LANG_HOOKS_MAKE_TYPE cxx_make_type
 175 #undef LANG_HOOKS_TYPE_FOR_MODE
 176 #define LANG_HOOKS_TYPE_FOR_MODE c_common_type_for_mode
 177 #undef LANG_HOOKS_TYPE_FOR_SIZE
 178 #define LANG_HOOKS_TYPE_FOR_SIZE c_common_type_for_size
 179 #undef LANG_HOOKS_SIGNED_TYPE
 180 #define LANG_HOOKS_SIGNED_TYPE c_common_signed_type
 181 #undef LANG_HOOKS_UNSIGNED_TYPE
 182 #define LANG_HOOKS_UNSIGNED_TYPE c_common_unsigned_type
 183 #undef LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE
 184 #define LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE c_common_signed_or_unsigned_type
 185 #undef LANG_HOOKS_INCOMPLETE_TYPE_ERROR
 186 #define LANG_HOOKS_INCOMPLETE_TYPE_ERROR cxx_incomplete_type_error
 187 #undef LANG_HOOKS_TYPE_PROMOTES_TO
 188 #define LANG_HOOKS_TYPE_PROMOTES_TO cxx_type_promotes_to
 189 #undef LANG_HOOKS_REGISTER_BUILTIN_TYPE
 190 #define LANG_HOOKS_REGISTER_BUILTIN_TYPE c_register_builtin_type
 191
 192 /* Each front end provides its own hooks, for toplev.c.  */
 193 const struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 194
 195 /* Tree code classes.  */
 196
 197 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
 198
 199 const char tree_code_type[] = {
 200 #include "tree.def"
 201   'x',
 202 #include "c-common.def"
 203   'x',
 204 #include "cp-tree.def"
 205 };
 206 #undef DEFTREECODE
 207
 208 /* Table indexed by tree code giving number of expression
 209    operands beyond the fixed part of the node structure.
 210    Not used for types or decls.  */
 211
 212 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
 213
 214 const unsigned char tree_code_length[] = {
 215 #include "tree.def"
 216   0,
 217 #include "c-common.def"
 218   0,
 219 #include "cp-tree.def"
 220 };
 221 #undef DEFTREECODE
 222
 223 /* Names of tree components.
 224    Used for printing out the tree and error messages.  */
 225 #define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,
 226
 227 const char *const tree_code_name[] = {
 228 #include "tree.def"
 229   "@@dummy",
 230 #include "c-common.def"
 231   "@@dummy",
 232 #include "cp-tree.def"
 233 };
 234 #undef DEFTREECODE
 235
 236 /* Check if a C++ type is safe for aliasing.
 237    Return TRUE if T safe for aliasing FALSE otherwise.  */
 238
 239 static bool
 240 ok_to_generate_alias_set_for_type (tree t)
 241 {
 242   if (TYPE_PTRMEMFUNC_P (t))
 243     return true;
 244   if (AGGREGATE_TYPE_P (t))
 245     {
 246       if ((TREE_CODE (t) == RECORD_TYPE) || (TREE_CODE (t) == UNION_TYPE))
 247         {
 248           tree fields;
 249           /* Backend-created structs are safe.  */
 250           if (! CLASS_TYPE_P (t))
 251             return true;
 252           /* PODs are safe.  */
 253           if (! CLASSTYPE_NON_POD_P(t))
 254             return true;
 255           /* Classes with virtual baseclasses are not.  */
 256           if (TYPE_USES_VIRTUAL_BASECLASSES (t))
 257             return false;
 258           /* Recursively check the base classes.  */
 259           if (TYPE_BINFO (t) != NULL && TYPE_BINFO_BASETYPES (t) != NULL)
 260             {
 261               int i;
 262               for (i = 0; i < TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (t)); i++)
 263                 {
 264                   tree binfo = TREE_VEC_ELT (TYPE_BINFO_BASETYPES (t), i);
 265                   if (!ok_to_generate_alias_set_for_type (BINFO_TYPE (binfo)))
 266                     return false;
 267                 }
 268             }
 269           /* Check all the fields.  */
 270           for (fields = TYPE_FIELDS (t); fields; fields = TREE_CHAIN (fields))
 271             {
 272               if (TREE_CODE (fields) != FIELD_DECL)
 273                 continue;
 274               if (! ok_to_generate_alias_set_for_type (TREE_TYPE (fields)))
 275                 return false;
 276             }
 277           return true;
 278         }
 279       else if (TREE_CODE (t) == ARRAY_TYPE)
 280         return ok_to_generate_alias_set_for_type (TREE_TYPE (t));
 281       else
 282         /* This should never happen, we dealt with all the aggregate
 283            types that can appear in C++ above.  */
 284         abort ();
 285     }
 286   else
 287     return true;
 288 }
 289
 290 /* Special routine to get the alias set for C++.  */
 291
 292 static HOST_WIDE_INT
 293 cxx_get_alias_set (tree t)
 294 {
 295   if (TREE_CODE (t) == RECORD_TYPE
 296       && TYPE_CONTEXT (t) && CLASS_TYPE_P (TYPE_CONTEXT (t))
 297       && CLASSTYPE_AS_BASE (TYPE_CONTEXT (t)) == t)
 298     /* The base variant of a type must be in the same alias set as the
 299        complete type.  */
 300     return get_alias_set (TYPE_CONTEXT (t));
 301
 302   if (/* It's not yet safe to use alias sets for some classes in C++.  */
 303       !ok_to_generate_alias_set_for_type (t)
 304       /* Nor is it safe to use alias sets for pointers-to-member
 305          functions, due to the fact that there may be more than one
 306          RECORD_TYPE type corresponding to the same pointer-to-member
 307          type.  */
 308       || TYPE_PTRMEMFUNC_P (t))
 309     return 0;
 310
 311   return c_common_get_alias_set (t);
 312 }
 313
 314 /* Called from check_global_declarations.  */
 315
 316 static bool
 317 cxx_warn_unused_global_decl (tree decl)
 318 {
 319   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 320     return false;
 321   if (DECL_IN_SYSTEM_HEADER (decl))
 322     return false;
 323
 324   /* Const variables take the place of #defines in C++.  */
 325   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 326     return false;
 327
 328   return true;
 329 }
 330
 331 /* Langhook for expr_size: Tell the backend that the value of an expression
 332    of non-POD class type does not include any tail padding; a derived class
 333    might have allocated something there.  */
 334
 335 static tree
 336 cp_expr_size (tree exp)
 337 {
 338   if (CLASS_TYPE_P (TREE_TYPE (exp)))
 339     {
 340       /* The backend should not be interested in the size of an expression
 341          of a type with both of these set; all copies of such types must go
 342          through a constructor or assignment op.  */
 343       if (TYPE_HAS_COMPLEX_INIT_REF (TREE_TYPE (exp))
 344           && TYPE_HAS_COMPLEX_ASSIGN_REF (TREE_TYPE (exp))
 345           /* But storing a CONSTRUCTOR isn't a copy.  */
 346           && TREE_CODE (exp) != CONSTRUCTOR)
 347         abort ();
 348       /* This would be wrong for a type with virtual bases, but they are
 349          caught by the abort above.  */
 350       return (is_empty_class (TREE_TYPE (exp))
 351               ? size_zero_node
 352               : CLASSTYPE_SIZE_UNIT (TREE_TYPE (exp)));
 353     }
 354   else
 355     /* Use the default code.  */
 356     return lhd_expr_size (exp);
 357 }
 358
 359 /* Langhook for tree_size: determine size of our 'x' and 'c' nodes.  */
 360 static size_t
 361 cp_tree_size (enum tree_code code)
 362 {
 363   switch (code)
 364     {
 365     case PTRMEM_CST:            return sizeof (struct ptrmem_cst);
 366     case BASELINK:              return sizeof (struct tree_baselink);
 367     case TEMPLATE_PARM_INDEX:   return sizeof (template_parm_index);
 368     case DEFAULT_ARG:           return sizeof (struct tree_default_arg);
 369     case OVERLOAD:              return sizeof (struct tree_overload);
 370     case WRAPPER:               return sizeof (struct tree_wrapper);
 371     default:
 372       abort ();
 373     }
 374   /* NOTREACHED */
 375 }
 376
 377 /* Returns true if T is a variably modified type, in the sense of C99.
 378    This routine needs only check cases that cannot be handled by the
 379    language-independent logic in tree-inline.c.  */
 380
 381 static bool
 382 cp_var_mod_type_p (tree type)
 383 {
 384   /* If TYPE is a pointer-to-member, it is variably modified if either
 385      the class or the member are variably modified.  */
 386   if (TYPE_PTR_TO_MEMBER_P (type))
 387     return (variably_modified_type_p (TYPE_PTRMEM_CLASS_TYPE (type))
 388             || variably_modified_type_p (TYPE_PTRMEM_POINTED_TO_TYPE (type)));
 389
 390   /* All other types are not variably modified.  */
 391   return false;
 392 }
 393
 394 /* Stub routine to tell people that this doesn't work yet.  */
 395 void
 396 c_reset_state (void)
 397 {
 398   sorry ("inter-module optimisations not implemented yet");
 399 }
 400
 401 /* Construct a C++-aware pretty-printer for CONTEXT.  It is assumed
 402    that CONTEXT->printer is an already constructed basic pretty_printer.  */
 403 static void
 404 cxx_initialize_diagnostics (diagnostic_context *context)
 405 {
 406   pretty_printer *base = context->printer;
 407   cxx_pretty_printer *pp = xmalloc (sizeof (cxx_pretty_printer));
 408   memcpy (pp_base (pp), base, sizeof (pretty_printer));
 409   pp_cxx_pretty_printer_init (pp);
 410   context->printer = (pretty_printer *) pp;
 411
 412   /* It is safe to free this object because it was previously malloc()'d.  */
 413   free (base);
 414 }