gcc/cp/cp-lang.c

   1 /* Language-dependent hooks for C++.
   2    Copyright 2001, 2002, 2004 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 cxx_warn_unused_global_decl (tree);
  39 static tree cp_expr_size (tree);
  40 static size_t cp_tree_size (enum tree_code);
  41 static bool cp_var_mod_type_p (tree, tree);
  42 static int cxx_types_compatible_p (tree, 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_EXPAND_DECL
  74 #define LANG_HOOKS_EXPAND_DECL c_expand_decl
  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_TRUTHVALUE_CONVERSION
  80 #define LANG_HOOKS_TRUTHVALUE_CONVERSION c_common_truthvalue_conversion
  81 #undef LANG_HOOKS_UNSAFE_FOR_REEVAL
  82 #define LANG_HOOKS_UNSAFE_FOR_REEVAL c_common_unsafe_for_reeval
  83 #undef LANG_HOOKS_SET_DECL_ASSEMBLER_NAME
  84 #define LANG_HOOKS_SET_DECL_ASSEMBLER_NAME mangle_decl
  85 #undef LANG_HOOKS_MARK_ADDRESSABLE
  86 #define LANG_HOOKS_MARK_ADDRESSABLE cxx_mark_addressable
  87 #undef LANG_HOOKS_PRINT_STATISTICS
  88 #define LANG_HOOKS_PRINT_STATISTICS cxx_print_statistics
  89 #undef LANG_HOOKS_PRINT_XNODE
  90 #define LANG_HOOKS_PRINT_XNODE cxx_print_xnode
  91 #undef LANG_HOOKS_PRINT_DECL
  92 #define LANG_HOOKS_PRINT_DECL cxx_print_decl
  93 #undef LANG_HOOKS_PRINT_TYPE
  94 #define LANG_HOOKS_PRINT_TYPE cxx_print_type
  95 #undef LANG_HOOKS_PRINT_IDENTIFIER
  96 #define LANG_HOOKS_PRINT_IDENTIFIER cxx_print_identifier
  97 #undef LANG_HOOKS_DECL_PRINTABLE_NAME
  98 #define LANG_HOOKS_DECL_PRINTABLE_NAME  cxx_printable_name
  99 #undef LANG_HOOKS_PRINT_ERROR_FUNCTION
 100 #define LANG_HOOKS_PRINT_ERROR_FUNCTION cxx_print_error_function
 101 #undef LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL
 102 #define LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL cxx_warn_unused_global_decl
 103 #undef LANG_HOOKS_WRITE_GLOBALS
 104 #define LANG_HOOKS_WRITE_GLOBALS lhd_do_nothing
 105
 106
 107 #undef LANG_HOOKS_FUNCTION_INIT
 108 #define LANG_HOOKS_FUNCTION_INIT cxx_push_function_context
 109 #undef LANG_HOOKS_FUNCTION_FINAL
 110 #define LANG_HOOKS_FUNCTION_FINAL cxx_pop_function_context
 111 #undef LANG_HOOKS_FUNCTION_MISSING_NORETURN_OK_P
 112 #define LANG_HOOKS_FUNCTION_MISSING_NORETURN_OK_P cp_missing_noreturn_ok_p
 113
 114 /* Attribute hooks.  */
 115 #undef LANG_HOOKS_COMMON_ATTRIBUTE_TABLE
 116 #define LANG_HOOKS_COMMON_ATTRIBUTE_TABLE c_common_attribute_table
 117 #undef LANG_HOOKS_FORMAT_ATTRIBUTE_TABLE
 118 #define LANG_HOOKS_FORMAT_ATTRIBUTE_TABLE c_common_format_attribute_table
 119 #undef LANG_HOOKS_ATTRIBUTE_TABLE
 120 #define LANG_HOOKS_ATTRIBUTE_TABLE cxx_attribute_table
 121
 122 #undef LANG_HOOKS_TREE_INLINING_WALK_SUBTREES
 123 #define LANG_HOOKS_TREE_INLINING_WALK_SUBTREES \
 124   cp_walk_subtrees
 125 #undef LANG_HOOKS_TREE_INLINING_CANNOT_INLINE_TREE_FN
 126 #define LANG_HOOKS_TREE_INLINING_CANNOT_INLINE_TREE_FN \
 127   cp_cannot_inline_tree_fn
 128 #undef LANG_HOOKS_TREE_INLINING_ADD_PENDING_FN_DECLS
 129 #define LANG_HOOKS_TREE_INLINING_ADD_PENDING_FN_DECLS \
 130   cp_add_pending_fn_decls
 131 #undef LANG_HOOKS_TREE_INLINING_AUTO_VAR_IN_FN_P
 132 #define LANG_HOOKS_TREE_INLINING_AUTO_VAR_IN_FN_P \
 133   cp_auto_var_in_fn_p
 134 #undef LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P
 135 #define LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P anon_aggr_type_p
 136 #undef LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P
 137 #define LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P cp_var_mod_type_p
 138 #undef LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN
 139 #define LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN cp_dump_tree
 140 #undef LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN
 141 #define LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN cp_type_quals
 142 #undef LANG_HOOKS_EXPR_SIZE
 143 #define LANG_HOOKS_EXPR_SIZE cp_expr_size
 144
 145 #undef LANG_HOOKS_CALLGRAPH_ANALYZE_EXPR
 146 #define LANG_HOOKS_CALLGRAPH_ANALYZE_EXPR cxx_callgraph_analyze_expr
 147 #undef LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION
 148 #define LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION expand_body
 149
 150 #undef LANG_HOOKS_MAKE_TYPE
 151 #define LANG_HOOKS_MAKE_TYPE cxx_make_type
 152 #undef LANG_HOOKS_TYPE_FOR_MODE
 153 #define LANG_HOOKS_TYPE_FOR_MODE c_common_type_for_mode
 154 #undef LANG_HOOKS_TYPE_FOR_SIZE
 155 #define LANG_HOOKS_TYPE_FOR_SIZE c_common_type_for_size
 156 #undef LANG_HOOKS_SIGNED_TYPE
 157 #define LANG_HOOKS_SIGNED_TYPE c_common_signed_type
 158 #undef LANG_HOOKS_UNSIGNED_TYPE
 159 #define LANG_HOOKS_UNSIGNED_TYPE c_common_unsigned_type
 160 #undef LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE
 161 #define LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE c_common_signed_or_unsigned_type
 162 #undef LANG_HOOKS_INCOMPLETE_TYPE_ERROR
 163 #define LANG_HOOKS_INCOMPLETE_TYPE_ERROR cxx_incomplete_type_error
 164 #undef LANG_HOOKS_TYPE_PROMOTES_TO
 165 #define LANG_HOOKS_TYPE_PROMOTES_TO cxx_type_promotes_to
 166 #undef LANG_HOOKS_TYPES_COMPATIBLE_P
 167 #define LANG_HOOKS_TYPES_COMPATIBLE_P cxx_types_compatible_p
 168 #undef LANG_HOOKS_REGISTER_BUILTIN_TYPE
 169 #define LANG_HOOKS_REGISTER_BUILTIN_TYPE c_register_builtin_type
 170 #undef LANG_HOOKS_GIMPLIFY_EXPR
 171 #define LANG_HOOKS_GIMPLIFY_EXPR cp_gimplify_expr
 172 #undef LANG_HOOKS_FOLD_OBJ_TYPE_REF
 173 #define LANG_HOOKS_FOLD_OBJ_TYPE_REF cp_fold_obj_type_ref
 174
 175 /* Each front end provides its own hooks, for toplev.c.  */
 176 const struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 177
 178 /* Tree code classes.  */
 179
 180 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
 181
 182 const char tree_code_type[] = {
 183 #include "tree.def"
 184   'x',
 185 #include "c-common.def"
 186   'x',
 187 #include "cp-tree.def"
 188 };
 189 #undef DEFTREECODE
 190
 191 /* Table indexed by tree code giving number of expression
 192    operands beyond the fixed part of the node structure.
 193    Not used for types or decls.  */
 194
 195 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
 196
 197 const unsigned char tree_code_length[] = {
 198 #include "tree.def"
 199   0,
 200 #include "c-common.def"
 201   0,
 202 #include "cp-tree.def"
 203 };
 204 #undef DEFTREECODE
 205
 206 /* Names of tree components.
 207    Used for printing out the tree and error messages.  */
 208 #define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,
 209
 210 const char *const tree_code_name[] = {
 211 #include "tree.def"
 212   "@@dummy",
 213 #include "c-common.def"
 214   "@@dummy",
 215 #include "cp-tree.def"
 216 };
 217 #undef DEFTREECODE
 218
 219 /* Special routine to get the alias set for C++.  */
 220
 221 static HOST_WIDE_INT
 222 cxx_get_alias_set (tree t)
 223 {
 224   if (IS_FAKE_BASE_TYPE (t))
 225     /* The base variant of a type must be in the same alias set as the
 226        complete type.  */
 227     return get_alias_set (TYPE_CONTEXT (t));
 228
 229   /* Punt on PMFs until we canonicalize functions properly.  */
 230   if (TYPE_PTRMEMFUNC_P (t))
 231     return 0;
 232
 233   return c_common_get_alias_set (t);
 234 }
 235
 236 /* Called from check_global_declarations.  */
 237
 238 static bool
 239 cxx_warn_unused_global_decl (tree decl)
 240 {
 241   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 242     return false;
 243   if (DECL_IN_SYSTEM_HEADER (decl))
 244     return false;
 245
 246   /* Const variables take the place of #defines in C++.  */
 247   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 248     return false;
 249
 250   return true;
 251 }
 252
 253 /* Langhook for expr_size: Tell the backend that the value of an expression
 254    of non-POD class type does not include any tail padding; a derived class
 255    might have allocated something there.  */
 256
 257 static tree
 258 cp_expr_size (tree exp)
 259 {
 260   if (CLASS_TYPE_P (TREE_TYPE (exp)))
 261     {
 262       /* The backend should not be interested in the size of an expression
 263          of a type with both of these set; all copies of such types must go
 264          through a constructor or assignment op.  */
 265       if (TYPE_HAS_COMPLEX_INIT_REF (TREE_TYPE (exp))
 266           && TYPE_HAS_COMPLEX_ASSIGN_REF (TREE_TYPE (exp))
 267           /* But storing a CONSTRUCTOR isn't a copy.  */
 268           && TREE_CODE (exp) != CONSTRUCTOR)
 269         abort ();
 270       /* This would be wrong for a type with virtual bases, but they are
 271          caught by the abort above.  */
 272       return (is_empty_class (TREE_TYPE (exp))
 273               ? size_zero_node
 274               : CLASSTYPE_SIZE_UNIT (TREE_TYPE (exp)));
 275     }
 276   else
 277     /* Use the default code.  */
 278     return lhd_expr_size (exp);
 279 }
 280
 281 /* Langhook for tree_size: determine size of our 'x' and 'c' nodes.  */
 282 static size_t
 283 cp_tree_size (enum tree_code code)
 284 {
 285   switch (code)
 286     {
 287     case TINST_LEVEL:           return sizeof (struct tinst_level_s);
 288     case PTRMEM_CST:            return sizeof (struct ptrmem_cst);
 289     case BASELINK:              return sizeof (struct tree_baselink);
 290     case TEMPLATE_PARM_INDEX:   return sizeof (template_parm_index);
 291     case DEFAULT_ARG:           return sizeof (struct tree_default_arg);
 292     case OVERLOAD:              return sizeof (struct tree_overload);
 293     default:
 294       abort ();
 295     }
 296   /* NOTREACHED */
 297 }
 298
 299 /* Returns true if T is a variably modified type, in the sense of C99.
 300    FN is as passed to variably_modified_p.
 301    This routine needs only check cases that cannot be handled by the
 302    language-independent logic in tree.c.  */
 303
 304 static bool
 305 cp_var_mod_type_p (tree type, tree fn)
 306 {
 307   /* If TYPE is a pointer-to-member, it is variably modified if either
 308      the class or the member are variably modified.  */
 309   if (TYPE_PTR_TO_MEMBER_P (type))
 310     return (variably_modified_type_p (TYPE_PTRMEM_CLASS_TYPE (type), fn)
 311             || variably_modified_type_p (TYPE_PTRMEM_POINTED_TO_TYPE (type),
 312                                          fn));
 313
 314   /* All other types are not variably modified.  */
 315   return false;
 316 }
 317
 318 /* This compares two types for equivalence ("compatible" in C-based languages).
 319    This routine should only return 1 if it is sure.  It should not be used
 320    in contexts where erroneously returning 0 causes problems.  */
 321
 322 static int cxx_types_compatible_p (tree x, tree y)
 323 {
 324   if (same_type_ignoring_top_level_qualifiers_p (x, y))
 325     return 1;
 326
 327   /* Once we get to the middle-end, references and pointers are
 328      interchangeable.  FIXME should we try to replace all references with
 329      pointers?  */
 330   if (POINTER_TYPE_P (x) && POINTER_TYPE_P (y)
 331       && same_type_p (TREE_TYPE (x), TREE_TYPE (y)))
 332     return 1;
 333
 334   return 0;
 335 }
 336
 337 /* Construct a C++-aware pretty-printer for CONTEXT.  It is assumed
 338    that CONTEXT->printer is an already constructed basic pretty_printer.  */
 339 static void
 340 cxx_initialize_diagnostics (diagnostic_context *context)
 341 {
 342   pretty_printer *base = context->printer;
 343   cxx_pretty_printer *pp = xmalloc (sizeof (cxx_pretty_printer));
 344   memcpy (pp_base (pp), base, sizeof (pretty_printer));
 345   pp_cxx_pretty_printer_init (pp);
 346   context->printer = (pretty_printer *) pp;
 347
 348   /* It is safe to free this object because it was previously malloc()'d.  */
 349   free (base);
 350 }
 351
 352 /* Stubs to keep c-opts.c happy.  */
 353 void
 354 push_file_scope (void)
 355 {
 356 }
 357
 358 void
 359 pop_file_scope (void)
 360 {
 361 }
 362
 363 /* c-pragma.c needs to query whether a decl has extern "C" linkage.  */
 364 bool
 365 has_c_linkage (tree decl)
 366 {
 367   return DECL_EXTERN_C_P (decl);
 368 }