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_COPY_RES_DECL_FOR_INLINING
 135 #define LANG_HOOKS_TREE_INLINING_COPY_RES_DECL_FOR_INLINING \
 136   cp_copy_res_decl_for_inlining
 137 #undef LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P
 138 #define LANG_HOOKS_TREE_INLINING_ANON_AGGR_TYPE_P anon_aggr_type_p
 139 #undef LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P
 140 #define LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P cp_var_mod_type_p
 141 #undef LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN
 142 #define LANG_HOOKS_TREE_DUMP_DUMP_TREE_FN cp_dump_tree
 143 #undef LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN
 144 #define LANG_HOOKS_TREE_DUMP_TYPE_QUALS_FN cp_type_quals
 145 #undef LANG_HOOKS_EXPR_SIZE
 146 #define LANG_HOOKS_EXPR_SIZE cp_expr_size
 147
 148 #undef LANG_HOOKS_CALLGRAPH_ANALYZE_EXPR
 149 #define LANG_HOOKS_CALLGRAPH_ANALYZE_EXPR cxx_callgraph_analyze_expr
 150 #undef LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION
 151 #define LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION expand_body
 152
 153 #undef LANG_HOOKS_MAKE_TYPE
 154 #define LANG_HOOKS_MAKE_TYPE cxx_make_type
 155 #undef LANG_HOOKS_TYPE_FOR_MODE
 156 #define LANG_HOOKS_TYPE_FOR_MODE c_common_type_for_mode
 157 #undef LANG_HOOKS_TYPE_FOR_SIZE
 158 #define LANG_HOOKS_TYPE_FOR_SIZE c_common_type_for_size
 159 #undef LANG_HOOKS_SIGNED_TYPE
 160 #define LANG_HOOKS_SIGNED_TYPE c_common_signed_type
 161 #undef LANG_HOOKS_UNSIGNED_TYPE
 162 #define LANG_HOOKS_UNSIGNED_TYPE c_common_unsigned_type
 163 #undef LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE
 164 #define LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE c_common_signed_or_unsigned_type
 165 #undef LANG_HOOKS_INCOMPLETE_TYPE_ERROR
 166 #define LANG_HOOKS_INCOMPLETE_TYPE_ERROR cxx_incomplete_type_error
 167 #undef LANG_HOOKS_TYPE_PROMOTES_TO
 168 #define LANG_HOOKS_TYPE_PROMOTES_TO cxx_type_promotes_to
 169 #undef LANG_HOOKS_TYPES_COMPATIBLE_P
 170 #define LANG_HOOKS_TYPES_COMPATIBLE_P cxx_types_compatible_p
 171 #undef LANG_HOOKS_REGISTER_BUILTIN_TYPE
 172 #define LANG_HOOKS_REGISTER_BUILTIN_TYPE c_register_builtin_type
 173 #undef LANG_HOOKS_GIMPLIFY_EXPR
 174 #define LANG_HOOKS_GIMPLIFY_EXPR cp_gimplify_expr
 175 #undef LANG_HOOKS_FOLD_OBJ_TYPE_REF
 176 #define LANG_HOOKS_FOLD_OBJ_TYPE_REF cp_fold_obj_type_ref
 177
 178 /* Each front end provides its own hooks, for toplev.c.  */
 179 const struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 180
 181 /* Tree code classes.  */
 182
 183 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
 184
 185 const char tree_code_type[] = {
 186 #include "tree.def"
 187   'x',
 188 #include "c-common.def"
 189   'x',
 190 #include "cp-tree.def"
 191 };
 192 #undef DEFTREECODE
 193
 194 /* Table indexed by tree code giving number of expression
 195    operands beyond the fixed part of the node structure.
 196    Not used for types or decls.  */
 197
 198 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
 199
 200 const unsigned char tree_code_length[] = {
 201 #include "tree.def"
 202   0,
 203 #include "c-common.def"
 204   0,
 205 #include "cp-tree.def"
 206 };
 207 #undef DEFTREECODE
 208
 209 /* Names of tree components.
 210    Used for printing out the tree and error messages.  */
 211 #define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,
 212
 213 const char *const tree_code_name[] = {
 214 #include "tree.def"
 215   "@@dummy",
 216 #include "c-common.def"
 217   "@@dummy",
 218 #include "cp-tree.def"
 219 };
 220 #undef DEFTREECODE
 221
 222 /* Special routine to get the alias set for C++.  */
 223
 224 static HOST_WIDE_INT
 225 cxx_get_alias_set (tree t)
 226 {
 227   if (IS_FAKE_BASE_TYPE (t))
 228     /* The base variant of a type must be in the same alias set as the
 229        complete type.  */
 230     return get_alias_set (TYPE_CONTEXT (t));
 231
 232   /* Punt on PMFs until we canonicalize functions properly.  */
 233   if (TYPE_PTRMEMFUNC_P (t))
 234     return 0;
 235
 236   return c_common_get_alias_set (t);
 237 }
 238
 239 /* Called from check_global_declarations.  */
 240
 241 static bool
 242 cxx_warn_unused_global_decl (tree decl)
 243 {
 244   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 245     return false;
 246   if (DECL_IN_SYSTEM_HEADER (decl))
 247     return false;
 248
 249   /* Const variables take the place of #defines in C++.  */
 250   if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
 251     return false;
 252
 253   return true;
 254 }
 255
 256 /* Langhook for expr_size: Tell the backend that the value of an expression
 257    of non-POD class type does not include any tail padding; a derived class
 258    might have allocated something there.  */
 259
 260 static tree
 261 cp_expr_size (tree exp)
 262 {
 263   if (CLASS_TYPE_P (TREE_TYPE (exp)))
 264     {
 265       /* The backend should not be interested in the size of an expression
 266          of a type with both of these set; all copies of such types must go
 267          through a constructor or assignment op.  */
 268       if (TYPE_HAS_COMPLEX_INIT_REF (TREE_TYPE (exp))
 269           && TYPE_HAS_COMPLEX_ASSIGN_REF (TREE_TYPE (exp))
 270           /* But storing a CONSTRUCTOR isn't a copy.  */
 271           && TREE_CODE (exp) != CONSTRUCTOR)
 272         abort ();
 273       /* This would be wrong for a type with virtual bases, but they are
 274          caught by the abort above.  */
 275       return (is_empty_class (TREE_TYPE (exp))
 276               ? size_zero_node
 277               : CLASSTYPE_SIZE_UNIT (TREE_TYPE (exp)));
 278     }
 279   else
 280     /* Use the default code.  */
 281     return lhd_expr_size (exp);
 282 }
 283
 284 /* Langhook for tree_size: determine size of our 'x' and 'c' nodes.  */
 285 static size_t
 286 cp_tree_size (enum tree_code code)
 287 {
 288   switch (code)
 289     {
 290     case PTRMEM_CST:            return sizeof (struct ptrmem_cst);
 291     case BASELINK:              return sizeof (struct tree_baselink);
 292     case TEMPLATE_PARM_INDEX:   return sizeof (template_parm_index);
 293     case DEFAULT_ARG:           return sizeof (struct tree_default_arg);
 294     case OVERLOAD:              return sizeof (struct tree_overload);
 295     default:
 296       abort ();
 297     }
 298   /* NOTREACHED */
 299 }
 300
 301 /* Returns true if T is a variably modified type, in the sense of C99.
 302    FN is as passed to variably_modified_p.
 303    This routine needs only check cases that cannot be handled by the
 304    language-independent logic in tree.c.  */
 305
 306 static bool
 307 cp_var_mod_type_p (tree type, tree fn)
 308 {
 309   /* If TYPE is a pointer-to-member, it is variably modified if either
 310      the class or the member are variably modified.  */
 311   if (TYPE_PTR_TO_MEMBER_P (type))
 312     return (variably_modified_type_p (TYPE_PTRMEM_CLASS_TYPE (type), fn)
 313             || variably_modified_type_p (TYPE_PTRMEM_POINTED_TO_TYPE (type),
 314                                          fn));
 315
 316   /* All other types are not variably modified.  */
 317   return false;
 318 }
 319
 320 /* This compares two types for equivalence ("compatible" in C-based languages).
 321    This routine should only return 1 if it is sure.  It should not be used
 322    in contexts where erroneously returning 0 causes problems.  */
 323
 324 static int cxx_types_compatible_p (tree x, tree y)
 325 {
 326   if (same_type_ignoring_top_level_qualifiers_p (x, y))
 327     return 1;
 328
 329   /* Once we get to the middle-end, references and pointers are
 330      interchangeable.  FIXME should we try to replace all references with
 331      pointers?  */
 332   if (POINTER_TYPE_P (x) && POINTER_TYPE_P (y)
 333       && same_type_p (TREE_TYPE (x), TREE_TYPE (y)))
 334     return 1;
 335
 336   return 0;
 337 }
 338
 339 /* Construct a C++-aware pretty-printer for CONTEXT.  It is assumed
 340    that CONTEXT->printer is an already constructed basic pretty_printer.  */
 341 static void
 342 cxx_initialize_diagnostics (diagnostic_context *context)
 343 {
 344   pretty_printer *base = context->printer;
 345   cxx_pretty_printer *pp = xmalloc (sizeof (cxx_pretty_printer));
 346   memcpy (pp_base (pp), base, sizeof (pretty_printer));
 347   pp_cxx_pretty_printer_init (pp);
 348   context->printer = (pretty_printer *) pp;
 349
 350   /* It is safe to free this object because it was previously malloc()'d.  */
 351   free (base);
 352 }
 353
 354 /* Stubs to keep c-opts.c happy.  */
 355 void
 356 push_file_scope (void)
 357 {
 358 }
 359
 360 void
 361 pop_file_scope (void)
 362 {
 363 }
 364
 365 /* c-pragma.c needs to query whether a decl has extern "C" linkage.  */
 366 bool
 367 has_c_linkage (tree decl)
 368 {
 369   return DECL_EXTERN_C_P (decl);
 370 }