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