gcc/cp/class.c

   1 /* Functions related to building classes and their related objects.
   2    Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007
   4    Free Software Foundation, Inc.
   5    Contributed by Michael Tiemann (tiemann@cygnus.com)
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify
  10 it under the terms of the GNU General Public License as published by
  11 the Free Software Foundation; either version 2, or (at your option)
  12 any later version.
  13
  14 GCC is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING.  If not, write to
  21 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  22 Boston, MA 02110-1301, USA.  */
  23
  24
  25 /* High-level class interface.  */
  26
  27 #include "config.h"
  28 #include "system.h"
  29 #include "coretypes.h"
  30 #include "tm.h"
  31 #include "tree.h"
  32 #include "cp-tree.h"
  33 #include "flags.h"
  34 #include "rtl.h"
  35 #include "output.h"
  36 #include "toplev.h"
  37 #include "target.h"
  38 #include "convert.h"
  39 #include "cgraph.h"
  40 #include "tree-dump.h"
  41
  42 /* The number of nested classes being processed.  If we are not in the
  43    scope of any class, this is zero.  */
  44
  45 int current_class_depth;
  46
  47 /* In order to deal with nested classes, we keep a stack of classes.
  48    The topmost entry is the innermost class, and is the entry at index
  49    CURRENT_CLASS_DEPTH  */
  50
  51 typedef struct class_stack_node {
  52   /* The name of the class.  */
  53   tree name;
  54
  55   /* The _TYPE node for the class.  */
  56   tree type;
  57
  58   /* The access specifier pending for new declarations in the scope of
  59      this class.  */
  60   tree access;
  61
  62   /* If were defining TYPE, the names used in this class.  */
  63   splay_tree names_used;
  64
  65   /* Nonzero if this class is no longer open, because of a call to
  66      push_to_top_level.  */
  67   size_t hidden;
  68 }* class_stack_node_t;
  69
  70 typedef struct vtbl_init_data_s
  71 {
  72   /* The base for which we're building initializers.  */
  73   tree binfo;
  74   /* The type of the most-derived type.  */
  75   tree derived;
  76   /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
  77      unless ctor_vtbl_p is true.  */
  78   tree rtti_binfo;
  79   /* The negative-index vtable initializers built up so far.  These
  80      are in order from least negative index to most negative index.  */
  81   tree inits;
  82   /* The last (i.e., most negative) entry in INITS.  */
  83   tree* last_init;
  84   /* The binfo for the virtual base for which we're building
  85      vcall offset initializers.  */
  86   tree vbase;
  87   /* The functions in vbase for which we have already provided vcall
  88      offsets.  */
  89   VEC(tree,gc) *fns;
  90   /* The vtable index of the next vcall or vbase offset.  */
  91   tree index;
  92   /* Nonzero if we are building the initializer for the primary
  93      vtable.  */
  94   int primary_vtbl_p;
  95   /* Nonzero if we are building the initializer for a construction
  96      vtable.  */
  97   int ctor_vtbl_p;
  98   /* True when adding vcall offset entries to the vtable.  False when
  99      merely computing the indices.  */
 100   bool generate_vcall_entries;
 101 } vtbl_init_data;
 102
 103 /* The type of a function passed to walk_subobject_offsets.  */
 104 typedef int (*subobject_offset_fn) (tree, tree, splay_tree);
 105
 106 /* The stack itself.  This is a dynamically resized array.  The
 107    number of elements allocated is CURRENT_CLASS_STACK_SIZE.  */
 108 static int current_class_stack_size;
 109 static class_stack_node_t current_class_stack;
 110
 111 /* The size of the largest empty class seen in this translation unit.  */
 112 static GTY (()) tree sizeof_biggest_empty_class;
 113
 114 /* An array of all local classes present in this translation unit, in
 115    declaration order.  */
 116 VEC(tree,gc) *local_classes;
 117
 118 static tree get_vfield_name (tree);
 119 static void finish_struct_anon (tree);
 120 static tree get_vtable_name (tree);
 121 static tree get_basefndecls (tree, tree);
 122 static int build_primary_vtable (tree, tree);
 123 static int build_secondary_vtable (tree);
 124 static void finish_vtbls (tree);
 125 static void modify_vtable_entry (tree, tree, tree, tree, tree *);
 126 static void finish_struct_bits (tree);
 127 static int alter_access (tree, tree, tree);
 128 static void handle_using_decl (tree, tree);
 129 static tree dfs_modify_vtables (tree, void *);
 130 static tree modify_all_vtables (tree, tree);
 131 static void determine_primary_bases (tree);
 132 static void finish_struct_methods (tree);
 133 static void maybe_warn_about_overly_private_class (tree);
 134 static int method_name_cmp (const void *, const void *);
 135 static int resort_method_name_cmp (const void *, const void *);
 136 static void add_implicitly_declared_members (tree, int, int);
 137 static tree fixed_type_or_null (tree, int *, int *);
 138 static tree build_simple_base_path (tree expr, tree binfo);
 139 static tree build_vtbl_ref_1 (tree, tree);
 140 static tree build_vtbl_initializer (tree, tree, tree, tree, int *);
 141 static int count_fields (tree);
 142 static int add_fields_to_record_type (tree, struct sorted_fields_type*, int);
 143 static void check_bitfield_decl (tree);
 144 static void check_field_decl (tree, tree, int *, int *, int *);
 145 static void check_field_decls (tree, tree *, int *, int *);
 146 static tree *build_base_field (record_layout_info, tree, splay_tree, tree *);
 147 static void build_base_fields (record_layout_info, splay_tree, tree *);
 148 static void check_methods (tree);
 149 static void remove_zero_width_bit_fields (tree);
 150 static void check_bases (tree, int *, int *);
 151 static void check_bases_and_members (tree);
 152 static tree create_vtable_ptr (tree, tree *);
 153 static void include_empty_classes (record_layout_info);
 154 static void layout_class_type (tree, tree *);
 155 static void fixup_pending_inline (tree);
 156 static void fixup_inline_methods (tree);
 157 static void propagate_binfo_offsets (tree, tree);
 158 static void layout_virtual_bases (record_layout_info, splay_tree);
 159 static void build_vbase_offset_vtbl_entries (tree, vtbl_init_data *);
 160 static void add_vcall_offset_vtbl_entries_r (tree, vtbl_init_data *);
 161 static void add_vcall_offset_vtbl_entries_1 (tree, vtbl_init_data *);
 162 static void build_vcall_offset_vtbl_entries (tree, vtbl_init_data *);
 163 static void add_vcall_offset (tree, tree, vtbl_init_data *);
 164 static void layout_vtable_decl (tree, int);
 165 static tree dfs_find_final_overrider_pre (tree, void *);
 166 static tree dfs_find_final_overrider_post (tree, void *);
 167 static tree find_final_overrider (tree, tree, tree);
 168 static int make_new_vtable (tree, tree);
 169 static tree get_primary_binfo (tree);
 170 static int maybe_indent_hierarchy (FILE *, int, int);
 171 static tree dump_class_hierarchy_r (FILE *, int, tree, tree, int);
 172 static void dump_class_hierarchy (tree);
 173 static void dump_class_hierarchy_1 (FILE *, int, tree);
 174 static void dump_array (FILE *, tree);
 175 static void dump_vtable (tree, tree, tree);
 176 static void dump_vtt (tree, tree);
 177 static void dump_thunk (FILE *, int, tree);
 178 static tree build_vtable (tree, tree, tree);
 179 static void initialize_vtable (tree, tree);
 180 static void layout_nonempty_base_or_field (record_layout_info,
 181                                            tree, tree, splay_tree);
 182 static tree end_of_class (tree, int);
 183 static bool layout_empty_base (tree, tree, splay_tree);
 184 static void accumulate_vtbl_inits (tree, tree, tree, tree, tree);
 185 static tree dfs_accumulate_vtbl_inits (tree, tree, tree, tree,
 186                                                tree);
 187 static void build_rtti_vtbl_entries (tree, vtbl_init_data *);
 188 static void build_vcall_and_vbase_vtbl_entries (tree, vtbl_init_data *);
 189 static void clone_constructors_and_destructors (tree);
 190 static tree build_clone (tree, tree);
 191 static void update_vtable_entry_for_fn (tree, tree, tree, tree *, unsigned);
 192 static void build_ctor_vtbl_group (tree, tree);
 193 static void build_vtt (tree);
 194 static tree binfo_ctor_vtable (tree);
 195 static tree *build_vtt_inits (tree, tree, tree *, tree *);
 196 static tree dfs_build_secondary_vptr_vtt_inits (tree, void *);
 197 static tree dfs_fixup_binfo_vtbls (tree, void *);
 198 static int record_subobject_offset (tree, tree, splay_tree);
 199 static int check_subobject_offset (tree, tree, splay_tree);
 200 static int walk_subobject_offsets (tree, subobject_offset_fn,
 201                                    tree, splay_tree, tree, int);
 202 static void record_subobject_offsets (tree, tree, splay_tree, bool);
 203 static int layout_conflict_p (tree, tree, splay_tree, int);
 204 static int splay_tree_compare_integer_csts (splay_tree_key k1,
 205                                             splay_tree_key k2);
 206 static void warn_about_ambiguous_bases (tree);
 207 static bool type_requires_array_cookie (tree);
 208 static bool contains_empty_class_p (tree);
 209 static bool base_derived_from (tree, tree);
 210 static int empty_base_at_nonzero_offset_p (tree, tree, splay_tree);
 211 static tree end_of_base (tree);
 212 static tree get_vcall_index (tree, tree);
 213
 214 /* Variables shared between class.c and call.c.  */
 215
 216 #ifdef GATHER_STATISTICS
 217 int n_vtables = 0;
 218 int n_vtable_entries = 0;
 219 int n_vtable_searches = 0;
 220 int n_vtable_elems = 0;
 221 int n_convert_harshness = 0;
 222 int n_compute_conversion_costs = 0;
 223 int n_inner_fields_searched = 0;
 224 #endif
 225
 226 /* Convert to or from a base subobject.  EXPR is an expression of type
 227    `A' or `A*', an expression of type `B' or `B*' is returned.  To
 228    convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
 229    the B base instance within A.  To convert base A to derived B, CODE
 230    is MINUS_EXPR and BINFO is the binfo for the A instance within B.
 231    In this latter case, A must not be a morally virtual base of B.
 232    NONNULL is true if EXPR is known to be non-NULL (this is only
 233    needed when EXPR is of pointer type).  CV qualifiers are preserved
 234    from EXPR.  */
 235
 236 tree
 237 build_base_path (enum tree_code code,
 238                  tree expr,
 239                  tree binfo,
 240                  int nonnull)
 241 {
 242   tree v_binfo = NULL_TREE;
 243   tree d_binfo = NULL_TREE;
 244   tree probe;
 245   tree offset;
 246   tree target_type;
 247   tree null_test = NULL;
 248   tree ptr_target_type;
 249   int fixed_type_p;
 250   int want_pointer = TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE;
 251   bool has_empty = false;
 252   bool virtual_access;
 253
 254   if (expr == error_mark_node || binfo == error_mark_node || !binfo)
 255     return error_mark_node;
 256
 257   for (probe = binfo; probe; probe = BINFO_INHERITANCE_CHAIN (probe))
 258     {
 259       d_binfo = probe;
 260       if (is_empty_class (BINFO_TYPE (probe)))
 261         has_empty = true;
 262       if (!v_binfo && BINFO_VIRTUAL_P (probe))
 263         v_binfo = probe;
 264     }
 265
 266   probe = TYPE_MAIN_VARIANT (TREE_TYPE (expr));
 267   if (want_pointer)
 268     probe = TYPE_MAIN_VARIANT (TREE_TYPE (probe));
 269
 270   gcc_assert ((code == MINUS_EXPR
 271                && SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), probe))
 272               || (code == PLUS_EXPR
 273                   && SAME_BINFO_TYPE_P (BINFO_TYPE (d_binfo), probe)));
 274
 275   if (binfo == d_binfo)
 276     /* Nothing to do.  */
 277     return expr;
 278
 279   if (code == MINUS_EXPR && v_binfo)
 280     {
 281       error ("cannot convert from base %qT to derived type %qT via virtual base %qT",
 282              BINFO_TYPE (binfo), BINFO_TYPE (d_binfo), BINFO_TYPE (v_binfo));
 283       return error_mark_node;
 284     }
 285
 286   if (!want_pointer)
 287     /* This must happen before the call to save_expr.  */
 288     expr = build_unary_op (ADDR_EXPR, expr, 0);
 289
 290   offset = BINFO_OFFSET (binfo);
 291   fixed_type_p = resolves_to_fixed_type_p (expr, &nonnull);
 292   target_type = code == PLUS_EXPR ? BINFO_TYPE (binfo) : BINFO_TYPE (d_binfo);
 293
 294   /* Do we need to look in the vtable for the real offset?  */
 295   virtual_access = (v_binfo && fixed_type_p <= 0);
 296
 297   /* Do we need to check for a null pointer?  */
 298   if (want_pointer && !nonnull)
 299     {
 300       /* If we know the conversion will not actually change the value
 301          of EXPR, then we can avoid testing the expression for NULL.
 302          We have to avoid generating a COMPONENT_REF for a base class
 303          field, because other parts of the compiler know that such
 304          expressions are always non-NULL.  */
 305       if (!virtual_access && integer_zerop (offset))
 306         return build_nop (build_pointer_type (target_type), expr);
 307       null_test = error_mark_node;
 308     }
 309
 310   /* Protect against multiple evaluation if necessary.  */
 311   if (TREE_SIDE_EFFECTS (expr) && (null_test || virtual_access))
 312     expr = save_expr (expr);
 313
 314   /* Now that we've saved expr, build the real null test.  */
 315   if (null_test)
 316     {
 317       tree zero = cp_convert (TREE_TYPE (expr), integer_zero_node);
 318       null_test = fold_build2 (NE_EXPR, boolean_type_node,
 319                                expr, zero);
 320     }
 321
 322   /* If this is a simple base reference, express it as a COMPONENT_REF.  */
 323   if (code == PLUS_EXPR && !virtual_access
 324       /* We don't build base fields for empty bases, and they aren't very
 325          interesting to the optimizers anyway.  */
 326       && !has_empty)
 327     {
 328       expr = build_indirect_ref (expr, NULL);
 329       expr = build_simple_base_path (expr, binfo);
 330       if (want_pointer)
 331         expr = build_address (expr);
 332       target_type = TREE_TYPE (expr);
 333       goto out;
 334     }
 335
 336   if (virtual_access)
 337     {
 338       /* Going via virtual base V_BINFO.  We need the static offset
 339          from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
 340          V_BINFO.  That offset is an entry in D_BINFO's vtable.  */
 341       tree v_offset;
 342
 343       if (fixed_type_p < 0 && in_base_initializer)
 344         {
 345           /* In a base member initializer, we cannot rely on the
 346              vtable being set up.  We have to indirect via the
 347              vtt_parm.  */
 348           tree t;
 349
 350           t = TREE_TYPE (TYPE_VFIELD (current_class_type));
 351           t = build_pointer_type (t);
 352           v_offset = convert (t, current_vtt_parm);
 353           v_offset = build_indirect_ref (v_offset, NULL);
 354         }
 355       else
 356         v_offset = build_vfield_ref (build_indirect_ref (expr, NULL),
 357                                      TREE_TYPE (TREE_TYPE (expr)));
 358
 359       v_offset = build2 (PLUS_EXPR, TREE_TYPE (v_offset),
 360                          v_offset,  BINFO_VPTR_FIELD (v_binfo));
 361       v_offset = build1 (NOP_EXPR,
 362                          build_pointer_type (ptrdiff_type_node),
 363                          v_offset);
 364       v_offset = build_indirect_ref (v_offset, NULL);
 365       TREE_CONSTANT (v_offset) = 1;
 366       TREE_INVARIANT (v_offset) = 1;
 367
 368       offset = convert_to_integer (ptrdiff_type_node,
 369                                    size_diffop (offset,
 370                                                 BINFO_OFFSET (v_binfo)));
 371
 372       if (!integer_zerop (offset))
 373         v_offset = build2 (code, ptrdiff_type_node, v_offset, offset);
 374
 375       if (fixed_type_p < 0)
 376         /* Negative fixed_type_p means this is a constructor or destructor;
 377            virtual base layout is fixed in in-charge [cd]tors, but not in
 378            base [cd]tors.  */
 379         offset = build3 (COND_EXPR, ptrdiff_type_node,
 380                          build2 (EQ_EXPR, boolean_type_node,
 381                                  current_in_charge_parm, integer_zero_node),
 382                          v_offset,
 383                          convert_to_integer (ptrdiff_type_node,
 384                                              BINFO_OFFSET (binfo)));
 385       else
 386         offset = v_offset;
 387     }
 388
 389   target_type = cp_build_qualified_type
 390     (target_type, cp_type_quals (TREE_TYPE (TREE_TYPE (expr))));
 391   ptr_target_type = build_pointer_type (target_type);
 392   if (want_pointer)
 393     target_type = ptr_target_type;
 394
 395   expr = build1 (NOP_EXPR, ptr_target_type, expr);
 396
 397   if (!integer_zerop (offset))
 398     expr = build2 (code, ptr_target_type, expr, offset);
 399   else
 400     null_test = NULL;
 401
 402   if (!want_pointer)
 403     expr = build_indirect_ref (expr, NULL);
 404
 405  out:
 406   if (null_test)
 407     expr = fold_build3 (COND_EXPR, target_type, null_test, expr,
 408                         fold_build1 (NOP_EXPR, target_type,
 409                                      integer_zero_node));
 410
 411   return expr;
 412 }
 413
 414 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
 415    Perform a derived-to-base conversion by recursively building up a
 416    sequence of COMPONENT_REFs to the appropriate base fields.  */
 417
 418 static tree
 419 build_simple_base_path (tree expr, tree binfo)
 420 {
 421   tree type = BINFO_TYPE (binfo);
 422   tree d_binfo = BINFO_INHERITANCE_CHAIN (binfo);
 423   tree field;
 424
 425   if (d_binfo == NULL_TREE)
 426     {
 427       tree temp;
 428
 429       gcc_assert (TYPE_MAIN_VARIANT (TREE_TYPE (expr)) == type);
 430
 431       /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
 432          into `(*(a ?  &b : &c)).x', and so on.  A COND_EXPR is only
 433          an lvalue in the front end; only _DECLs and _REFs are lvalues
 434          in the back end.  */
 435       temp = unary_complex_lvalue (ADDR_EXPR, expr);
 436       if (temp)
 437         expr = build_indirect_ref (temp, NULL);
 438
 439       return expr;
 440     }
 441
 442   /* Recurse.  */
 443   expr = build_simple_base_path (expr, d_binfo);
 444
 445   for (field = TYPE_FIELDS (BINFO_TYPE (d_binfo));
 446        field; field = TREE_CHAIN (field))
 447     /* Is this the base field created by build_base_field?  */
 448     if (TREE_CODE (field) == FIELD_DECL
 449         && DECL_FIELD_IS_BASE (field)
 450         && TREE_TYPE (field) == type)
 451       {
 452         /* We don't use build_class_member_access_expr here, as that
 453            has unnecessary checks, and more importantly results in
 454            recursive calls to dfs_walk_once.  */
 455         int type_quals = cp_type_quals (TREE_TYPE (expr));
 456
 457         expr = build3 (COMPONENT_REF,
 458                        cp_build_qualified_type (type, type_quals),
 459                        expr, field, NULL_TREE);
 460         expr = fold_if_not_in_template (expr);
 461
 462         /* Mark the expression const or volatile, as appropriate.
 463            Even though we've dealt with the type above, we still have
 464            to mark the expression itself.  */
 465         if (type_quals & TYPE_QUAL_CONST)
 466           TREE_READONLY (expr) = 1;
 467         if (type_quals & TYPE_QUAL_VOLATILE)
 468           TREE_THIS_VOLATILE (expr) = 1;
 469
 470         return expr;
 471       }
 472
 473   /* Didn't find the base field?!?  */
 474   gcc_unreachable ();
 475 }
 476
 477 /* Convert OBJECT to the base TYPE.  OBJECT is an expression whose
 478    type is a class type or a pointer to a class type.  In the former
 479    case, TYPE is also a class type; in the latter it is another
 480    pointer type.  If CHECK_ACCESS is true, an error message is emitted
 481    if TYPE is inaccessible.  If OBJECT has pointer type, the value is
 482    assumed to be non-NULL.  */
 483
 484 tree
 485 convert_to_base (tree object, tree type, bool check_access, bool nonnull)
 486 {
 487   tree binfo;
 488   tree object_type;
 489
 490   if (TYPE_PTR_P (TREE_TYPE (object)))
 491     {
 492       object_type = TREE_TYPE (TREE_TYPE (object));
 493       type = TREE_TYPE (type);
 494     }
 495   else
 496     object_type = TREE_TYPE (object);
 497
 498   binfo = lookup_base (object_type, type,
 499                        check_access ? ba_check : ba_unique,
 500                        NULL);
 501   if (!binfo || binfo == error_mark_node)
 502     return error_mark_node;
 503
 504   return build_base_path (PLUS_EXPR, object, binfo, nonnull);
 505 }
 506
 507 /* EXPR is an expression with unqualified class type.  BASE is a base
 508    binfo of that class type.  Returns EXPR, converted to the BASE
 509    type.  This function assumes that EXPR is the most derived class;
 510    therefore virtual bases can be found at their static offsets.  */
 511
 512 tree
 513 convert_to_base_statically (tree expr, tree base)
 514 {
 515   tree expr_type;
 516
 517   expr_type = TREE_TYPE (expr);
 518   if (!SAME_BINFO_TYPE_P (BINFO_TYPE (base), expr_type))
 519     {
 520       tree pointer_type;
 521
 522       pointer_type = build_pointer_type (expr_type);
 523       expr = build_unary_op (ADDR_EXPR, expr, /*noconvert=*/1);
 524       if (!integer_zerop (BINFO_OFFSET (base)))
 525           expr = build2 (PLUS_EXPR, pointer_type, expr,
 526                          build_nop (pointer_type, BINFO_OFFSET (base)));
 527       expr = build_nop (build_pointer_type (BINFO_TYPE (base)), expr);
 528       expr = build1 (INDIRECT_REF, BINFO_TYPE (base), expr);
 529     }
 530
 531   return expr;
 532 }
 533
 534 \f
 535 tree
 536 build_vfield_ref (tree datum, tree type)
 537 {
 538   tree vfield, vcontext;
 539
 540   if (datum == error_mark_node)
 541     return error_mark_node;
 542
 543   /* First, convert to the requested type.  */
 544   if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (datum), type))
 545     datum = convert_to_base (datum, type, /*check_access=*/false,
 546                              /*nonnull=*/true);
 547
 548   /* Second, the requested type may not be the owner of its own vptr.
 549      If not, convert to the base class that owns it.  We cannot use
 550      convert_to_base here, because VCONTEXT may appear more than once
 551      in the inheritance hierarchy of TYPE, and thus direct conversion
 552      between the types may be ambiguous.  Following the path back up
 553      one step at a time via primary bases avoids the problem.  */
 554   vfield = TYPE_VFIELD (type);
 555   vcontext = DECL_CONTEXT (vfield);
 556   while (!same_type_ignoring_top_level_qualifiers_p (vcontext, type))
 557     {
 558       datum = build_simple_base_path (datum, CLASSTYPE_PRIMARY_BINFO (type));
 559       type = TREE_TYPE (datum);
 560     }
 561
 562   return build3 (COMPONENT_REF, TREE_TYPE (vfield), datum, vfield, NULL_TREE);
 563 }
 564
 565 /* Given an object INSTANCE, return an expression which yields the
 566    vtable element corresponding to INDEX.  There are many special
 567    cases for INSTANCE which we take care of here, mainly to avoid
 568    creating extra tree nodes when we don't have to.  */
 569
 570 static tree
 571 build_vtbl_ref_1 (tree instance, tree idx)
 572 {
 573   tree aref;
 574   tree vtbl = NULL_TREE;
 575
 576   /* Try to figure out what a reference refers to, and
 577      access its virtual function table directly.  */
 578
 579   int cdtorp = 0;
 580   tree fixed_type = fixed_type_or_null (instance, NULL, &cdtorp);
 581
 582   tree basetype = non_reference (TREE_TYPE (instance));
 583
 584   if (fixed_type && !cdtorp)
 585     {
 586       tree binfo = lookup_base (fixed_type, basetype,
 587                                 ba_unique | ba_quiet, NULL);
 588       if (binfo)
 589         vtbl = unshare_expr (BINFO_VTABLE (binfo));
 590     }
 591
 592   if (!vtbl)
 593     vtbl = build_vfield_ref (instance, basetype);
 594
 595   assemble_external (vtbl);
 596
 597   aref = build_array_ref (vtbl, idx);
 598   TREE_CONSTANT (aref) |= TREE_CONSTANT (vtbl) && TREE_CONSTANT (idx);
 599   TREE_INVARIANT (aref) = TREE_CONSTANT (aref);
 600
 601   return aref;
 602 }
 603
 604 tree
 605 build_vtbl_ref (tree instance, tree idx)
 606 {
 607   tree aref = build_vtbl_ref_1 (instance, idx);
 608
 609   return aref;
 610 }
 611
 612 /* Given a stable object pointer INSTANCE_PTR, return an expression which
 613    yields a function pointer corresponding to vtable element INDEX.  */
 614
 615 tree
 616 build_vfn_ref (tree instance_ptr, tree idx)
 617 {
 618   tree aref;
 619
 620   aref = build_vtbl_ref_1 (build_indirect_ref (instance_ptr, 0), idx);
 621
 622   /* When using function descriptors, the address of the
 623      vtable entry is treated as a function pointer.  */
 624   if (TARGET_VTABLE_USES_DESCRIPTORS)
 625     aref = build1 (NOP_EXPR, TREE_TYPE (aref),
 626                    build_unary_op (ADDR_EXPR, aref, /*noconvert=*/1));
 627
 628   /* Remember this as a method reference, for later devirtualization.  */
 629   aref = build3 (OBJ_TYPE_REF, TREE_TYPE (aref), aref, instance_ptr, idx);
 630
 631   return aref;
 632 }
 633
 634 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
 635    for the given TYPE.  */
 636
 637 static tree
 638 get_vtable_name (tree type)
 639 {
 640   return mangle_vtbl_for_type (type);
 641 }
 642
 643 /* DECL is an entity associated with TYPE, like a virtual table or an
 644    implicitly generated constructor.  Determine whether or not DECL
 645    should have external or internal linkage at the object file
 646    level.  This routine does not deal with COMDAT linkage and other
 647    similar complexities; it simply sets TREE_PUBLIC if it possible for
 648    entities in other translation units to contain copies of DECL, in
 649    the abstract.  */
 650
 651 void
 652 set_linkage_according_to_type (tree type, tree decl)
 653 {
 654   /* If TYPE involves a local class in a function with internal
 655      linkage, then DECL should have internal linkage too.  Other local
 656      classes have no linkage -- but if their containing functions
 657      have external linkage, it makes sense for DECL to have external
 658      linkage too.  That will allow template definitions to be merged,
 659      for example.  */
 660   if (no_linkage_check (type, /*relaxed_p=*/true))
 661     {
 662       TREE_PUBLIC (decl) = 0;
 663       DECL_INTERFACE_KNOWN (decl) = 1;
 664     }
 665   else
 666     TREE_PUBLIC (decl) = 1;
 667 }
 668
 669 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
 670    (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
 671    Use NAME for the name of the vtable, and VTABLE_TYPE for its type.  */
 672
 673 static tree
 674 build_vtable (tree class_type, tree name, tree vtable_type)
 675 {
 676   tree decl;
 677
 678   decl = build_lang_decl (VAR_DECL, name, vtable_type);
 679   /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
 680      now to avoid confusion in mangle_decl.  */
 681   SET_DECL_ASSEMBLER_NAME (decl, name);
 682   DECL_CONTEXT (decl) = class_type;
 683   DECL_ARTIFICIAL (decl) = 1;
 684   TREE_STATIC (decl) = 1;
 685   TREE_READONLY (decl) = 1;
 686   DECL_VIRTUAL_P (decl) = 1;
 687   DECL_ALIGN (decl) = TARGET_VTABLE_ENTRY_ALIGN;
 688   DECL_VTABLE_OR_VTT_P (decl) = 1;
 689   /* At one time the vtable info was grabbed 2 words at a time.  This
 690      fails on sparc unless you have 8-byte alignment.  (tiemann) */
 691   DECL_ALIGN (decl) = MAX (TYPE_ALIGN (double_type_node),
 692                            DECL_ALIGN (decl));
 693   set_linkage_according_to_type (class_type, decl);
 694   /* The vtable has not been defined -- yet.  */
 695   DECL_EXTERNAL (decl) = 1;
 696   DECL_NOT_REALLY_EXTERN (decl) = 1;
 697
 698   /* Mark the VAR_DECL node representing the vtable itself as a
 699      "gratuitous" one, thereby forcing dwarfout.c to ignore it.  It
 700      is rather important that such things be ignored because any
 701      effort to actually generate DWARF for them will run into
 702      trouble when/if we encounter code like:
 703
 704      #pragma interface
 705      struct S { virtual void member (); };
 706
 707      because the artificial declaration of the vtable itself (as
 708      manufactured by the g++ front end) will say that the vtable is
 709      a static member of `S' but only *after* the debug output for
 710      the definition of `S' has already been output.  This causes
 711      grief because the DWARF entry for the definition of the vtable
 712      will try to refer back to an earlier *declaration* of the
 713      vtable as a static member of `S' and there won't be one.  We
 714      might be able to arrange to have the "vtable static member"
 715      attached to the member list for `S' before the debug info for
 716      `S' get written (which would solve the problem) but that would
 717      require more intrusive changes to the g++ front end.  */
 718   DECL_IGNORED_P (decl) = 1;
 719
 720   return decl;
 721 }
 722
 723 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
 724    or even complete.  If this does not exist, create it.  If COMPLETE is
 725    nonzero, then complete the definition of it -- that will render it
 726    impossible to actually build the vtable, but is useful to get at those
 727    which are known to exist in the runtime.  */
 728
 729 tree
 730 get_vtable_decl (tree type, int complete)
 731 {
 732   tree decl;
 733
 734   if (CLASSTYPE_VTABLES (type))
 735     return CLASSTYPE_VTABLES (type);
 736
 737   decl = build_vtable (type, get_vtable_name (type), vtbl_type_node);
 738   CLASSTYPE_VTABLES (type) = decl;
 739
 740   if (complete)
 741     {
 742       DECL_EXTERNAL (decl) = 1;
 743       finish_decl (decl, NULL_TREE, NULL_TREE);
 744     }
 745
 746   return decl;
 747 }
 748
 749 /* Build the primary virtual function table for TYPE.  If BINFO is
 750    non-NULL, build the vtable starting with the initial approximation
 751    that it is the same as the one which is the head of the association
 752    list.  Returns a nonzero value if a new vtable is actually
 753    created.  */
 754
 755 static int
 756 build_primary_vtable (tree binfo, tree type)
 757 {
 758   tree decl;
 759   tree virtuals;
 760
 761   decl = get_vtable_decl (type, /*complete=*/0);
 762
 763   if (binfo)
 764     {
 765       if (BINFO_NEW_VTABLE_MARKED (binfo))
 766         /* We have already created a vtable for this base, so there's
 767            no need to do it again.  */
 768         return 0;
 769
 770       virtuals = copy_list (BINFO_VIRTUALS (binfo));
 771       TREE_TYPE (decl) = TREE_TYPE (get_vtbl_decl_for_binfo (binfo));
 772       DECL_SIZE (decl) = TYPE_SIZE (TREE_TYPE (decl));
 773       DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (TREE_TYPE (decl));
 774     }
 775   else
 776     {
 777       gcc_assert (TREE_TYPE (decl) == vtbl_type_node);
 778       virtuals = NULL_TREE;
 779     }
 780
 781 #ifdef GATHER_STATISTICS
 782   n_vtables += 1;
 783   n_vtable_elems += list_length (virtuals);
 784 #endif
 785
 786   /* Initialize the association list for this type, based
 787      on our first approximation.  */
 788   BINFO_VTABLE (TYPE_BINFO (type)) = decl;
 789   BINFO_VIRTUALS (TYPE_BINFO (type)) = virtuals;
 790   SET_BINFO_NEW_VTABLE_MARKED (TYPE_BINFO (type));
 791   return 1;
 792 }
 793
 794 /* Give BINFO a new virtual function table which is initialized
 795    with a skeleton-copy of its original initialization.  The only
 796    entry that changes is the `delta' entry, so we can really
 797    share a lot of structure.
 798
 799    FOR_TYPE is the most derived type which caused this table to
 800    be needed.
 801
 802    Returns nonzero if we haven't met BINFO before.
 803
 804    The order in which vtables are built (by calling this function) for
 805    an object must remain the same, otherwise a binary incompatibility
 806    can result.  */
 807
 808 static int
 809 build_secondary_vtable (tree binfo)
 810 {
 811   if (BINFO_NEW_VTABLE_MARKED (binfo))
 812     /* We already created a vtable for this base.  There's no need to
 813        do it again.  */
 814     return 0;
 815
 816   /* Remember that we've created a vtable for this BINFO, so that we
 817      don't try to do so again.  */
 818   SET_BINFO_NEW_VTABLE_MARKED (binfo);
 819
 820   /* Make fresh virtual list, so we can smash it later.  */
 821   BINFO_VIRTUALS (binfo) = copy_list (BINFO_VIRTUALS (binfo));
 822
 823   /* Secondary vtables are laid out as part of the same structure as
 824      the primary vtable.  */
 825   BINFO_VTABLE (binfo) = NULL_TREE;
 826   return 1;
 827 }
 828
 829 /* Create a new vtable for BINFO which is the hierarchy dominated by
 830    T. Return nonzero if we actually created a new vtable.  */
 831
 832 static int
 833 make_new_vtable (tree t, tree binfo)
 834 {
 835   if (binfo == TYPE_BINFO (t))
 836     /* In this case, it is *type*'s vtable we are modifying.  We start
 837        with the approximation that its vtable is that of the
 838        immediate base class.  */
 839     return build_primary_vtable (binfo, t);
 840   else
 841     /* This is our very own copy of `basetype' to play with.  Later,
 842        we will fill in all the virtual functions that override the
 843        virtual functions in these base classes which are not defined
 844        by the current type.  */
 845     return build_secondary_vtable (binfo);
 846 }
 847
 848 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
 849    (which is in the hierarchy dominated by T) list FNDECL as its
 850    BV_FN.  DELTA is the required constant adjustment from the `this'
 851    pointer where the vtable entry appears to the `this' required when
 852    the function is actually called.  */
 853
 854 static void
 855 modify_vtable_entry (tree t,
 856                      tree binfo,
 857                      tree fndecl,
 858                      tree delta,
 859                      tree *virtuals)
 860 {
 861   tree v;
 862
 863   v = *virtuals;
 864
 865   if (fndecl != BV_FN (v)
 866       || !tree_int_cst_equal (delta, BV_DELTA (v)))
 867     {
 868       /* We need a new vtable for BINFO.  */
 869       if (make_new_vtable (t, binfo))
 870         {
 871           /* If we really did make a new vtable, we also made a copy
 872              of the BINFO_VIRTUALS list.  Now, we have to find the
 873              corresponding entry in that list.  */
 874           *virtuals = BINFO_VIRTUALS (binfo);
 875           while (BV_FN (*virtuals) != BV_FN (v))
 876             *virtuals = TREE_CHAIN (*virtuals);
 877           v = *virtuals;
 878         }
 879
 880       BV_DELTA (v) = delta;
 881       BV_VCALL_INDEX (v) = NULL_TREE;
 882       BV_FN (v) = fndecl;
 883     }
 884 }
 885
 886 \f
 887 /* Add method METHOD to class TYPE.  If USING_DECL is non-null, it is
 888    the USING_DECL naming METHOD.  Returns true if the method could be
 889    added to the method vec.  */
 890
 891 bool
 892 add_method (tree type, tree method, tree using_decl)
 893 {
 894   unsigned slot;
 895   tree overload;
 896   bool template_conv_p = false;
 897   bool conv_p;
 898   VEC(tree,gc) *method_vec;
 899   bool complete_p;
 900   bool insert_p = false;
 901   tree current_fns;
 902   tree fns;
 903
 904   if (method == error_mark_node)
 905     return false;
 906
 907   complete_p = COMPLETE_TYPE_P (type);
 908   conv_p = DECL_CONV_FN_P (method);
 909   if (conv_p)
 910     template_conv_p = (TREE_CODE (method) == TEMPLATE_DECL
 911                        && DECL_TEMPLATE_CONV_FN_P (method));
 912
 913   method_vec = CLASSTYPE_METHOD_VEC (type);
 914   if (!method_vec)
 915     {
 916       /* Make a new method vector.  We start with 8 entries.  We must
 917          allocate at least two (for constructors and destructors), and
 918          we're going to end up with an assignment operator at some
 919          point as well.  */
 920       method_vec = VEC_alloc (tree, gc, 8);
 921       /* Create slots for constructors and destructors.  */
 922       VEC_quick_push (tree, method_vec, NULL_TREE);
 923       VEC_quick_push (tree, method_vec, NULL_TREE);
 924       CLASSTYPE_METHOD_VEC (type) = method_vec;
 925     }
 926
 927   /* Maintain TYPE_HAS_CONSTRUCTOR, etc.  */
 928   grok_special_member_properties (method);
 929
 930   /* Constructors and destructors go in special slots.  */
 931   if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (method))
 932     slot = CLASSTYPE_CONSTRUCTOR_SLOT;
 933   else if (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (method))
 934     {
 935       slot = CLASSTYPE_DESTRUCTOR_SLOT;
 936
 937       if (TYPE_FOR_JAVA (type))
 938         {
 939           if (!DECL_ARTIFICIAL (method))
 940             error ("Java class %qT cannot have a destructor", type);
 941           else if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
 942             error ("Java class %qT cannot have an implicit non-trivial "
 943                    "destructor",
 944                    type);
 945         }
 946     }
 947   else
 948     {
 949       tree m;
 950
 951       insert_p = true;
 952       /* See if we already have an entry with this name.  */
 953       for (slot = CLASSTYPE_FIRST_CONVERSION_SLOT;
 954            VEC_iterate (tree, method_vec, slot, m);
 955            ++slot)
 956         {
 957           m = OVL_CURRENT (m);
 958           if (template_conv_p)
 959             {
 960               if (TREE_CODE (m) == TEMPLATE_DECL
 961                   && DECL_TEMPLATE_CONV_FN_P (m))
 962                 insert_p = false;
 963               break;
 964             }
 965           if (conv_p && !DECL_CONV_FN_P (m))
 966             break;
 967           if (DECL_NAME (m) == DECL_NAME (method))
 968             {
 969               insert_p = false;
 970               break;
 971             }
 972           if (complete_p
 973               && !DECL_CONV_FN_P (m)
 974               && DECL_NAME (m) > DECL_NAME (method))
 975             break;
 976         }
 977     }
 978   current_fns = insert_p ? NULL_TREE : VEC_index (tree, method_vec, slot);
 979
 980   /* Check to see if we've already got this method.  */
 981   for (fns = current_fns; fns; fns = OVL_NEXT (fns))
 982     {
 983       tree fn = OVL_CURRENT (fns);
 984       tree fn_type;
 985       tree method_type;
 986       tree parms1;
 987       tree parms2;
 988
 989       if (TREE_CODE (fn) != TREE_CODE (method))
 990         continue;
 991
 992       /* [over.load] Member function declarations with the
 993          same name and the same parameter types cannot be
 994          overloaded if any of them is a static member
 995          function declaration.
 996
 997          [namespace.udecl] When a using-declaration brings names
 998          from a base class into a derived class scope, member
 999          functions in the derived class override and/or hide member
1000          functions with the same name and parameter types in a base
1001          class (rather than conflicting).  */
1002       fn_type = TREE_TYPE (fn);
1003       method_type = TREE_TYPE (method);
1004       parms1 = TYPE_ARG_TYPES (fn_type);
1005       parms2 = TYPE_ARG_TYPES (method_type);
1006
1007       /* Compare the quals on the 'this' parm.  Don't compare
1008          the whole types, as used functions are treated as
1009          coming from the using class in overload resolution.  */
1010       if (! DECL_STATIC_FUNCTION_P (fn)
1011           && ! DECL_STATIC_FUNCTION_P (method)
1012           && (TYPE_QUALS (TREE_TYPE (TREE_VALUE (parms1)))
1013               != TYPE_QUALS (TREE_TYPE (TREE_VALUE (parms2)))))
1014         continue;
1015
1016       /* For templates, the return type and template parameters
1017          must be identical.  */
1018       if (TREE_CODE (fn) == TEMPLATE_DECL
1019           && (!same_type_p (TREE_TYPE (fn_type),
1020                             TREE_TYPE (method_type))
1021               || !comp_template_parms (DECL_TEMPLATE_PARMS (fn),
1022                                        DECL_TEMPLATE_PARMS (method))))
1023         continue;
1024
1025       if (! DECL_STATIC_FUNCTION_P (fn))
1026         parms1 = TREE_CHAIN (parms1);
1027       if (! DECL_STATIC_FUNCTION_P (method))
1028         parms2 = TREE_CHAIN (parms2);
1029
1030       if (compparms (parms1, parms2)
1031           && (!DECL_CONV_FN_P (fn)
1032               || same_type_p (TREE_TYPE (fn_type),
1033                               TREE_TYPE (method_type))))
1034         {
1035           if (using_decl)
1036             {
1037               if (DECL_CONTEXT (fn) == type)
1038                 /* Defer to the local function.  */
1039                 return false;
1040               if (DECL_CONTEXT (fn) == DECL_CONTEXT (method))
1041                 error ("repeated using declaration %q+D", using_decl);
1042               else
1043                 error ("using declaration %q+D conflicts with a previous using declaration",
1044                        using_decl);
1045             }
1046           else
1047             {
1048               error ("%q+#D cannot be overloaded", method);
1049               error ("with %q+#D", fn);
1050             }
1051
1052           /* We don't call duplicate_decls here to merge the
1053              declarations because that will confuse things if the
1054              methods have inline definitions.  In particular, we
1055              will crash while processing the definitions.  */
1056           return false;
1057         }
1058     }
1059
1060   /* A class should never have more than one destructor.  */
1061   if (current_fns && DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (method))
1062     return false;
1063
1064   /* Add the new binding.  */
1065   overload = build_overload (method, current_fns);
1066
1067   if (conv_p)
1068     TYPE_HAS_CONVERSION (type) = 1;
1069   else if (slot >= CLASSTYPE_FIRST_CONVERSION_SLOT && !complete_p)
1070     push_class_level_binding (DECL_NAME (method), overload);
1071
1072   if (insert_p)
1073     {
1074       bool reallocated;
1075
1076       /* We only expect to add few methods in the COMPLETE_P case, so
1077          just make room for one more method in that case.  */
1078       if (complete_p)
1079         reallocated = VEC_reserve_exact (tree, gc, method_vec, 1);
1080       else
1081         reallocated = VEC_reserve (tree, gc, method_vec, 1);
1082       if (reallocated)
1083         CLASSTYPE_METHOD_VEC (type) = method_vec;
1084       if (slot == VEC_length (tree, method_vec))
1085         VEC_quick_push (tree, method_vec, overload);
1086       else
1087         VEC_quick_insert (tree, method_vec, slot, overload);
1088     }
1089   else
1090     /* Replace the current slot.  */
1091     VEC_replace (tree, method_vec, slot, overload);
1092   return true;
1093 }
1094
1095 /* Subroutines of finish_struct.  */
1096
1097 /* Change the access of FDECL to ACCESS in T.  Return 1 if change was
1098    legit, otherwise return 0.  */
1099
1100 static int
1101 alter_access (tree t, tree fdecl, tree access)
1102 {
1103   tree elem;
1104
1105   if (!DECL_LANG_SPECIFIC (fdecl))
1106     retrofit_lang_decl (fdecl);
1107
1108   gcc_assert (!DECL_DISCRIMINATOR_P (fdecl));
1109
1110   elem = purpose_member (t, DECL_ACCESS (fdecl));
1111   if (elem)
1112     {
1113       if (TREE_VALUE (elem) != access)
1114         {
1115           if (TREE_CODE (TREE_TYPE (fdecl)) == FUNCTION_DECL)
1116             error ("conflicting access specifications for method"
1117                    " %q+D, ignored", TREE_TYPE (fdecl));
1118           else
1119             error ("conflicting access specifications for field %qE, ignored",
1120                    DECL_NAME (fdecl));
1121         }
1122       else
1123         {
1124           /* They're changing the access to the same thing they changed
1125              it to before.  That's OK.  */
1126           ;
1127         }
1128     }
1129   else
1130     {
1131       perform_or_defer_access_check (TYPE_BINFO (t), fdecl, fdecl);
1132       DECL_ACCESS (fdecl) = tree_cons (t, access, DECL_ACCESS (fdecl));
1133       return 1;
1134     }
1135   return 0;
1136 }
1137
1138 /* Process the USING_DECL, which is a member of T.  */
1139
1140 static void
1141 handle_using_decl (tree using_decl, tree t)
1142 {
1143   tree decl = USING_DECL_DECLS (using_decl);
1144   tree name = DECL_NAME (using_decl);
1145   tree access
1146     = TREE_PRIVATE (using_decl) ? access_private_node
1147     : TREE_PROTECTED (using_decl) ? access_protected_node
1148     : access_public_node;
1149   tree flist = NULL_TREE;
1150   tree old_value;
1151
1152   gcc_assert (!processing_template_decl && decl);
1153
1154   old_value = lookup_member (t, name, /*protect=*/0, /*want_type=*/false);
1155   if (old_value)
1156     {
1157       if (is_overloaded_fn (old_value))
1158         old_value = OVL_CURRENT (old_value);
1159
1160       if (DECL_P (old_value) && DECL_CONTEXT (old_value) == t)
1161         /* OK */;
1162       else
1163         old_value = NULL_TREE;
1164     }
1165
1166   cp_emit_debug_info_for_using (decl, USING_DECL_SCOPE (using_decl));
1167
1168   if (is_overloaded_fn (decl))
1169     flist = decl;
1170
1171   if (! old_value)
1172     ;
1173   else if (is_overloaded_fn (old_value))
1174     {
1175       if (flist)
1176         /* It's OK to use functions from a base when there are functions with
1177            the same name already present in the current class.  */;
1178       else
1179         {
1180           error ("%q+D invalid in %q#T", using_decl, t);
1181           error ("  because of local method %q+#D with same name",
1182                  OVL_CURRENT (old_value));
1183           return;
1184         }
1185     }
1186   else if (!DECL_ARTIFICIAL (old_value))
1187     {
1188       error ("%q+D invalid in %q#T", using_decl, t);
1189       error ("  because of local member %q+#D with same name", old_value);
1190       return;
1191     }
1192
1193   /* Make type T see field decl FDECL with access ACCESS.  */
1194   if (flist)
1195     for (; flist; flist = OVL_NEXT (flist))
1196       {
1197         add_method (t, OVL_CURRENT (flist), using_decl);
1198         alter_access (t, OVL_CURRENT (flist), access);
1199       }
1200   else
1201     alter_access (t, decl, access);
1202 }
1203 \f
1204 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1205    and NO_CONST_ASN_REF_P.  Also set flag bits in T based on
1206    properties of the bases.  */
1207
1208 static void
1209 check_bases (tree t,
1210              int* cant_have_const_ctor_p,
1211              int* no_const_asn_ref_p)
1212 {
1213   int i;
1214   int seen_non_virtual_nearly_empty_base_p;
1215   tree base_binfo;
1216   tree binfo;
1217
1218   seen_non_virtual_nearly_empty_base_p = 0;
1219
1220   for (binfo = TYPE_BINFO (t), i = 0;
1221        BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
1222     {
1223       tree basetype = TREE_TYPE (base_binfo);
1224
1225       gcc_assert (COMPLETE_TYPE_P (basetype));
1226
1227       /* Effective C++ rule 14.  We only need to check TYPE_POLYMORPHIC_P
1228          here because the case of virtual functions but non-virtual
1229          dtor is handled in finish_struct_1.  */
1230       if (!TYPE_POLYMORPHIC_P (basetype))
1231         warning (OPT_Weffc__,
1232                  "base class %q#T has a non-virtual destructor", basetype);
1233
1234       /* If the base class doesn't have copy constructors or
1235          assignment operators that take const references, then the
1236          derived class cannot have such a member automatically
1237          generated.  */
1238       if (! TYPE_HAS_CONST_INIT_REF (basetype))
1239         *cant_have_const_ctor_p = 1;
1240       if (TYPE_HAS_ASSIGN_REF (basetype)
1241           && !TYPE_HAS_CONST_ASSIGN_REF (basetype))
1242         *no_const_asn_ref_p = 1;
1243
1244       if (BINFO_VIRTUAL_P (base_binfo))
1245         /* A virtual base does not effect nearly emptiness.  */
1246         ;
1247       else if (CLASSTYPE_NEARLY_EMPTY_P (basetype))
1248         {
1249           if (seen_non_virtual_nearly_empty_base_p)
1250             /* And if there is more than one nearly empty base, then the
1251                derived class is not nearly empty either.  */
1252             CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
1253           else
1254             /* Remember we've seen one.  */
1255             seen_non_virtual_nearly_empty_base_p = 1;
1256         }
1257       else if (!is_empty_class (basetype))
1258         /* If the base class is not empty or nearly empty, then this
1259            class cannot be nearly empty.  */
1260         CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
1261
1262       /* A lot of properties from the bases also apply to the derived
1263          class.  */
1264       TYPE_NEEDS_CONSTRUCTING (t) |= TYPE_NEEDS_CONSTRUCTING (basetype);
1265       TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
1266         |= TYPE_HAS_NONTRIVIAL_DESTRUCTOR (basetype);
1267       TYPE_HAS_COMPLEX_ASSIGN_REF (t)
1268         |= TYPE_HAS_COMPLEX_ASSIGN_REF (basetype);
1269       TYPE_HAS_COMPLEX_INIT_REF (t) |= TYPE_HAS_COMPLEX_INIT_REF (basetype);
1270       TYPE_POLYMORPHIC_P (t) |= TYPE_POLYMORPHIC_P (basetype);
1271       CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t)
1272         |= CLASSTYPE_CONTAINS_EMPTY_CLASS_P (basetype);
1273       TYPE_HAS_COMPLEX_DFLT (t) |= TYPE_HAS_COMPLEX_DFLT (basetype);
1274     }
1275 }
1276
1277 /* Determine all the primary bases within T.  Sets BINFO_PRIMARY_BASE_P for
1278    those that are primaries.  Sets BINFO_LOST_PRIMARY_P for those
1279    that have had a nearly-empty virtual primary base stolen by some
1280    other base in the hierarchy.  Determines CLASSTYPE_PRIMARY_BASE for
1281    T.  */
1282
1283 static void
1284 determine_primary_bases (tree t)
1285 {
1286   unsigned i;
1287   tree primary = NULL_TREE;
1288   tree type_binfo = TYPE_BINFO (t);
1289   tree base_binfo;
1290
1291   /* Determine the primary bases of our bases.  */
1292   for (base_binfo = TREE_CHAIN (type_binfo); base_binfo;
1293        base_binfo = TREE_CHAIN (base_binfo))
1294     {
1295       tree primary = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (base_binfo));
1296
1297       /* See if we're the non-virtual primary of our inheritance
1298          chain.  */
1299       if (!BINFO_VIRTUAL_P (base_binfo))
1300         {
1301           tree parent = BINFO_INHERITANCE_CHAIN (base_binfo);
1302           tree parent_primary = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (parent));
1303
1304           if (parent_primary
1305               && SAME_BINFO_TYPE_P (BINFO_TYPE (base_binfo),
1306                                     BINFO_TYPE (parent_primary)))
1307             /* We are the primary binfo.  */
1308             BINFO_PRIMARY_P (base_binfo) = 1;
1309         }
1310       /* Determine if we have a virtual primary base, and mark it so.
1311        */
1312       if (primary && BINFO_VIRTUAL_P (primary))
1313         {
1314           tree this_primary = copied_binfo (primary, base_binfo);
1315
1316           if (BINFO_PRIMARY_P (this_primary))
1317             /* Someone already claimed this base.  */
1318             BINFO_LOST_PRIMARY_P (base_binfo) = 1;
1319           else
1320             {
1321               tree delta;
1322
1323               BINFO_PRIMARY_P (this_primary) = 1;
1324               BINFO_INHERITANCE_CHAIN (this_primary) = base_binfo;
1325
1326               /* A virtual binfo might have been copied from within
1327                  another hierarchy. As we're about to use it as a
1328                  primary base, make sure the offsets match.  */
1329               delta = size_diffop (convert (ssizetype,
1330                                             BINFO_OFFSET (base_binfo)),
1331                                    convert (ssizetype,
1332                                             BINFO_OFFSET (this_primary)));
1333
1334               propagate_binfo_offsets (this_primary, delta);
1335             }
1336         }
1337     }
1338
1339   /* First look for a dynamic direct non-virtual base.  */
1340   for (i = 0; BINFO_BASE_ITERATE (type_binfo, i, base_binfo); i++)
1341     {
1342       tree basetype = BINFO_TYPE (base_binfo);
1343
1344       if (TYPE_CONTAINS_VPTR_P (basetype) && !BINFO_VIRTUAL_P (base_binfo))
1345         {
1346           primary = base_binfo;
1347           goto found;
1348         }
1349     }
1350
1351   /* A "nearly-empty" virtual base class can be the primary base
1352      class, if no non-virtual polymorphic base can be found.  Look for
1353      a nearly-empty virtual dynamic base that is not already a primary
1354      base of something in the hierarchy.  If there is no such base,
1355      just pick the first nearly-empty virtual base.  */
1356
1357   for (base_binfo = TREE_CHAIN (type_binfo); base_binfo;
1358        base_binfo = TREE_CHAIN (base_binfo))
1359     if (BINFO_VIRTUAL_P (base_binfo)
1360         && CLASSTYPE_NEARLY_EMPTY_P (BINFO_TYPE (base_binfo)))
1361       {
1362         if (!BINFO_PRIMARY_P (base_binfo))
1363           {
1364             /* Found one that is not primary.  */
1365             primary = base_binfo;
1366             goto found;
1367           }
1368         else if (!primary)
1369           /* Remember the first candidate.  */
1370           primary = base_binfo;
1371       }
1372
1373  found:
1374   /* If we've got a primary base, use it.  */
1375   if (primary)
1376     {
1377       tree basetype = BINFO_TYPE (primary);
1378
1379       CLASSTYPE_PRIMARY_BINFO (t) = primary;
1380       if (BINFO_PRIMARY_P (primary))
1381         /* We are stealing a primary base.  */
1382         BINFO_LOST_PRIMARY_P (BINFO_INHERITANCE_CHAIN (primary)) = 1;
1383       BINFO_PRIMARY_P (primary) = 1;
1384       if (BINFO_VIRTUAL_P (primary))
1385         {
1386           tree delta;
1387
1388           BINFO_INHERITANCE_CHAIN (primary) = type_binfo;
1389           /* A virtual binfo might have been copied from within
1390              another hierarchy. As we're about to use it as a primary
1391              base, make sure the offsets match.  */
1392           delta = size_diffop (ssize_int (0),
1393                                convert (ssizetype, BINFO_OFFSET (primary)));
1394
1395           propagate_binfo_offsets (primary, delta);
1396         }
1397
1398       primary = TYPE_BINFO (basetype);
1399
1400       TYPE_VFIELD (t) = TYPE_VFIELD (basetype);
1401       BINFO_VTABLE (type_binfo) = BINFO_VTABLE (primary);
1402       BINFO_VIRTUALS (type_binfo) = BINFO_VIRTUALS (primary);
1403     }
1404 }
1405 \f
1406 /* Set memoizing fields and bits of T (and its variants) for later
1407    use.  */
1408
1409 static void
1410 finish_struct_bits (tree t)
1411 {
1412   tree variants;
1413
1414   /* Fix up variants (if any).  */
1415   for (variants = TYPE_NEXT_VARIANT (t);
1416        variants;
1417        variants = TYPE_NEXT_VARIANT (variants))
1418     {
1419       /* These fields are in the _TYPE part of the node, not in
1420          the TYPE_LANG_SPECIFIC component, so they are not shared.  */
1421       TYPE_HAS_CONSTRUCTOR (variants) = TYPE_HAS_CONSTRUCTOR (t);
1422       TYPE_NEEDS_CONSTRUCTING (variants) = TYPE_NEEDS_CONSTRUCTING (t);
1423       TYPE_HAS_NONTRIVIAL_DESTRUCTOR (variants)
1424         = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t);
1425
1426       TYPE_POLYMORPHIC_P (variants) = TYPE_POLYMORPHIC_P (t);
1427
1428       TYPE_BINFO (variants) = TYPE_BINFO (t);
1429
1430       /* Copy whatever these are holding today.  */
1431       TYPE_VFIELD (variants) = TYPE_VFIELD (t);
1432       TYPE_METHODS (variants) = TYPE_METHODS (t);
1433       TYPE_FIELDS (variants) = TYPE_FIELDS (t);
1434     }
1435
1436   if (BINFO_N_BASE_BINFOS (TYPE_BINFO (t)) && TYPE_POLYMORPHIC_P (t))
1437     /* For a class w/o baseclasses, 'finish_struct' has set
1438        CLASSTYPE_PURE_VIRTUALS correctly (by definition).
1439        Similarly for a class whose base classes do not have vtables.
1440        When neither of these is true, we might have removed abstract
1441        virtuals (by providing a definition), added some (by declaring
1442        new ones), or redeclared ones from a base class.  We need to
1443        recalculate what's really an abstract virtual at this point (by
1444        looking in the vtables).  */
1445     get_pure_virtuals (t);
1446
1447   /* If this type has a copy constructor or a destructor, force its
1448      mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
1449      nonzero.  This will cause it to be passed by invisible reference
1450      and prevent it from being returned in a register.  */
1451   if (! TYPE_HAS_TRIVIAL_INIT_REF (t) || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t))
1452     {
1453       tree variants;
1454       DECL_MODE (TYPE_MAIN_DECL (t)) = BLKmode;
1455       for (variants = t; variants; variants = TYPE_NEXT_VARIANT (variants))
1456         {
1457           TYPE_MODE (variants) = BLKmode;
1458           TREE_ADDRESSABLE (variants) = 1;
1459         }
1460     }
1461 }
1462
1463 /* Issue warnings about T having private constructors, but no friends,
1464    and so forth.
1465
1466    HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
1467    static members.  HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
1468    non-private static member functions.  */
1469
1470 static void
1471 maybe_warn_about_overly_private_class (tree t)
1472 {
1473   int has_member_fn = 0;
1474   int has_nonprivate_method = 0;
1475   tree fn;
1476
1477   if (!warn_ctor_dtor_privacy
1478       /* If the class has friends, those entities might create and
1479          access instances, so we should not warn.  */
1480       || (CLASSTYPE_FRIEND_CLASSES (t)
1481           || DECL_FRIENDLIST (TYPE_MAIN_DECL (t)))
1482       /* We will have warned when the template was declared; there's
1483          no need to warn on every instantiation.  */
1484       || CLASSTYPE_TEMPLATE_INSTANTIATION (t))
1485     /* There's no reason to even consider warning about this
1486        class.  */
1487     return;
1488
1489   /* We only issue one warning, if more than one applies, because
1490      otherwise, on code like:
1491
1492      class A {
1493        // Oops - forgot `public:'
1494        A();
1495        A(const A&);
1496        ~A();
1497      };
1498
1499      we warn several times about essentially the same problem.  */
1500
1501   /* Check to see if all (non-constructor, non-destructor) member
1502      functions are private.  (Since there are no friends or
1503      non-private statics, we can't ever call any of the private member
1504      functions.)  */
1505   for (fn = TYPE_METHODS (t); fn; fn = TREE_CHAIN (fn))
1506     /* We're not interested in compiler-generated methods; they don't
1507        provide any way to call private members.  */
1508     if (!DECL_ARTIFICIAL (fn))
1509       {
1510         if (!TREE_PRIVATE (fn))
1511           {
1512             if (DECL_STATIC_FUNCTION_P (fn))
1513               /* A non-private static member function is just like a
1514                  friend; it can create and invoke private member
1515                  functions, and be accessed without a class
1516                  instance.  */
1517               return;
1518
1519             has_nonprivate_method = 1;
1520             /* Keep searching for a static member function.  */
1521           }
1522         else if (!DECL_CONSTRUCTOR_P (fn) && !DECL_DESTRUCTOR_P (fn))
1523           has_member_fn = 1;
1524       }
1525
1526   if (!has_nonprivate_method && has_member_fn)
1527     {
1528       /* There are no non-private methods, and there's at least one
1529          private member function that isn't a constructor or
1530          destructor.  (If all the private members are
1531          constructors/destructors we want to use the code below that
1532          issues error messages specifically referring to
1533          constructors/destructors.)  */
1534       unsigned i;
1535       tree binfo = TYPE_BINFO (t);
1536
1537       for (i = 0; i != BINFO_N_BASE_BINFOS (binfo); i++)
1538         if (BINFO_BASE_ACCESS (binfo, i) != access_private_node)
1539           {
1540             has_nonprivate_method = 1;
1541             break;
1542           }
1543       if (!has_nonprivate_method)
1544         {
1545           warning (OPT_Wctor_dtor_privacy,
1546                    "all member functions in class %qT are private", t);
1547           return;
1548         }
1549     }
1550
1551   /* Even if some of the member functions are non-private, the class
1552      won't be useful for much if all the constructors or destructors
1553      are private: such an object can never be created or destroyed.  */
1554   fn = CLASSTYPE_DESTRUCTORS (t);
1555   if (fn && TREE_PRIVATE (fn))
1556     {
1557       warning (OPT_Wctor_dtor_privacy,
1558                "%q#T only defines a private destructor and has no friends",
1559                t);
1560       return;
1561     }
1562
1563   if (TYPE_HAS_CONSTRUCTOR (t)
1564       /* Implicitly generated constructors are always public.  */
1565       && (!CLASSTYPE_LAZY_DEFAULT_CTOR (t)
1566           || !CLASSTYPE_LAZY_COPY_CTOR (t)))
1567     {
1568       int nonprivate_ctor = 0;
1569
1570       /* If a non-template class does not define a copy
1571          constructor, one is defined for it, enabling it to avoid
1572          this warning.  For a template class, this does not
1573          happen, and so we would normally get a warning on:
1574
1575            template <class T> class C { private: C(); };
1576
1577          To avoid this asymmetry, we check TYPE_HAS_INIT_REF.  All
1578          complete non-template or fully instantiated classes have this
1579          flag set.  */
1580       if (!TYPE_HAS_INIT_REF (t))
1581         nonprivate_ctor = 1;
1582       else
1583         for (fn = CLASSTYPE_CONSTRUCTORS (t); fn; fn = OVL_NEXT (fn))
1584           {
1585             tree ctor = OVL_CURRENT (fn);
1586             /* Ideally, we wouldn't count copy constructors (or, in
1587                fact, any constructor that takes an argument of the
1588                class type as a parameter) because such things cannot
1589                be used to construct an instance of the class unless
1590                you already have one.  But, for now at least, we're
1591                more generous.  */
1592             if (! TREE_PRIVATE (ctor))
1593               {
1594                 nonprivate_ctor = 1;
1595                 break;
1596               }
1597           }
1598
1599       if (nonprivate_ctor == 0)
1600         {
1601           warning (OPT_Wctor_dtor_privacy,
1602                    "%q#T only defines private constructors and has no friends",
1603                    t);
1604           return;
1605         }
1606     }
1607 }
1608
1609 static struct {
1610   gt_pointer_operator new_value;
1611   void *cookie;
1612 } resort_data;
1613
1614 /* Comparison function to compare two TYPE_METHOD_VEC entries by name.  */
1615
1616 static int
1617 method_name_cmp (const void* m1_p, const void* m2_p)
1618 {
1619   const tree *const m1 = (const tree *) m1_p;
1620   const tree *const m2 = (const tree *) m2_p;
1621
1622   if (*m1 == NULL_TREE && *m2 == NULL_TREE)
1623     return 0;
1624   if (*m1 == NULL_TREE)
1625     return -1;
1626   if (*m2 == NULL_TREE)
1627     return 1;
1628   if (DECL_NAME (OVL_CURRENT (*m1)) < DECL_NAME (OVL_CURRENT (*m2)))
1629     return -1;
1630   return 1;
1631 }
1632
1633 /* This routine compares two fields like method_name_cmp but using the
1634    pointer operator in resort_field_decl_data.  */
1635
1636 static int
1637 resort_method_name_cmp (const void* m1_p, const void* m2_p)
1638 {
1639   const tree *const m1 = (const tree *) m1_p;
1640   const tree *const m2 = (const tree *) m2_p;
1641   if (*m1 == NULL_TREE && *m2 == NULL_TREE)
1642     return 0;
1643   if (*m1 == NULL_TREE)
1644     return -1;
1645   if (*m2 == NULL_TREE)
1646     return 1;
1647   {
1648     tree d1 = DECL_NAME (OVL_CURRENT (*m1));
1649     tree d2 = DECL_NAME (OVL_CURRENT (*m2));
1650     resort_data.new_value (&d1, resort_data.cookie);
1651     resort_data.new_value (&d2, resort_data.cookie);
1652     if (d1 < d2)
1653       return -1;
1654   }
1655   return 1;
1656 }
1657
1658 /* Resort TYPE_METHOD_VEC because pointers have been reordered.  */
1659
1660 void
1661 resort_type_method_vec (void* obj,
1662                         void* orig_obj ATTRIBUTE_UNUSED ,
1663                         gt_pointer_operator new_value,
1664                         void* cookie)
1665 {
1666   VEC(tree,gc) *method_vec = (VEC(tree,gc) *) obj;
1667   int len = VEC_length (tree, method_vec);
1668   size_t slot;
1669   tree fn;
1670
1671   /* The type conversion ops have to live at the front of the vec, so we
1672      can't sort them.  */
1673   for (slot = CLASSTYPE_FIRST_CONVERSION_SLOT;
1674        VEC_iterate (tree, method_vec, slot, fn);
1675        ++slot)
1676     if (!DECL_CONV_FN_P (OVL_CURRENT (fn)))
1677       break;
1678
1679   if (len - slot > 1)
1680     {
1681       resort_data.new_value = new_value;
1682       resort_data.cookie = cookie;
1683       qsort (VEC_address (tree, method_vec) + slot, len - slot, sizeof (tree),
1684              resort_method_name_cmp);
1685     }
1686 }
1687
1688 /* Warn about duplicate methods in fn_fields.
1689
1690    Sort methods that are not special (i.e., constructors, destructors,
1691    and type conversion operators) so that we can find them faster in
1692    search.  */
1693
1694 static void
1695 finish_struct_methods (tree t)
1696 {
1697   tree fn_fields;
1698   VEC(tree,gc) *method_vec;
1699   int slot, len;
1700
1701   method_vec = CLASSTYPE_METHOD_VEC (t);
1702   if (!method_vec)
1703     return;
1704
1705   len = VEC_length (tree, method_vec);
1706
1707   /* Clear DECL_IN_AGGR_P for all functions.  */
1708   for (fn_fields = TYPE_METHODS (t); fn_fields;
1709        fn_fields = TREE_CHAIN (fn_fields))
1710     DECL_IN_AGGR_P (fn_fields) = 0;
1711
1712   /* Issue warnings about private constructors and such.  If there are
1713      no methods, then some public defaults are generated.  */
1714   maybe_warn_about_overly_private_class (t);
1715
1716   /* The type conversion ops have to live at the front of the vec, so we
1717      can't sort them.  */
1718   for (slot = CLASSTYPE_FIRST_CONVERSION_SLOT;
1719        VEC_iterate (tree, method_vec, slot, fn_fields);
1720        ++slot)
1721     if (!DECL_CONV_FN_P (OVL_CURRENT (fn_fields)))
1722       break;
1723   if (len - slot > 1)
1724     qsort (VEC_address (tree, method_vec) + slot,
1725            len-slot, sizeof (tree), method_name_cmp);
1726 }
1727
1728 /* Make BINFO's vtable have N entries, including RTTI entries,
1729    vbase and vcall offsets, etc.  Set its type and call the back end
1730    to lay it out.  */
1731
1732 static void
1733 layout_vtable_decl (tree binfo, int n)
1734 {
1735   tree atype;
1736   tree vtable;
1737
1738   atype = build_cplus_array_type (vtable_entry_type,
1739                                   build_index_type (size_int (n - 1)));
1740   layout_type (atype);
1741
1742   /* We may have to grow the vtable.  */
1743   vtable = get_vtbl_decl_for_binfo (binfo);
1744   if (!same_type_p (TREE_TYPE (vtable), atype))
1745     {
1746       TREE_TYPE (vtable) = atype;
1747       DECL_SIZE (vtable) = DECL_SIZE_UNIT (vtable) = NULL_TREE;
1748       layout_decl (vtable, 0);
1749     }
1750 }
1751
1752 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
1753    have the same signature.  */
1754
1755 int
1756 same_signature_p (tree fndecl, tree base_fndecl)
1757 {
1758   /* One destructor overrides another if they are the same kind of
1759      destructor.  */
1760   if (DECL_DESTRUCTOR_P (base_fndecl) && DECL_DESTRUCTOR_P (fndecl)
1761       && special_function_p (base_fndecl) == special_function_p (fndecl))
1762     return 1;
1763   /* But a non-destructor never overrides a destructor, nor vice
1764      versa, nor do different kinds of destructors override
1765      one-another.  For example, a complete object destructor does not
1766      override a deleting destructor.  */
1767   if (DECL_DESTRUCTOR_P (base_fndecl) || DECL_DESTRUCTOR_P (fndecl))
1768     return 0;
1769
1770   if (DECL_NAME (fndecl) == DECL_NAME (base_fndecl)
1771       || (DECL_CONV_FN_P (fndecl)
1772           && DECL_CONV_FN_P (base_fndecl)
1773           && same_type_p (DECL_CONV_FN_TYPE (fndecl),
1774                           DECL_CONV_FN_TYPE (base_fndecl))))
1775     {
1776       tree types, base_types;
1777       types = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
1778       base_types = TYPE_ARG_TYPES (TREE_TYPE (base_fndecl));
1779       if ((TYPE_QUALS (TREE_TYPE (TREE_VALUE (base_types)))
1780            == TYPE_QUALS (TREE_TYPE (TREE_VALUE (types))))
1781           && compparms (TREE_CHAIN (base_types), TREE_CHAIN (types)))
1782         return 1;
1783     }
1784   return 0;
1785 }
1786
1787 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
1788    subobject.  */
1789
1790 static bool
1791 base_derived_from (tree derived, tree base)
1792 {
1793   tree probe;
1794
1795   for (probe = base; probe; probe = BINFO_INHERITANCE_CHAIN (probe))
1796     {
1797       if (probe == derived)
1798         return true;
1799       else if (BINFO_VIRTUAL_P (probe))
1800         /* If we meet a virtual base, we can't follow the inheritance
1801            any more.  See if the complete type of DERIVED contains
1802            such a virtual base.  */
1803         return (binfo_for_vbase (BINFO_TYPE (probe), BINFO_TYPE (derived))
1804                 != NULL_TREE);
1805     }
1806   return false;
1807 }
1808
1809 typedef struct find_final_overrider_data_s {
1810   /* The function for which we are trying to find a final overrider.  */
1811   tree fn;
1812   /* The base class in which the function was declared.  */
1813   tree declaring_base;
1814   /* The candidate overriders.  */
1815   tree candidates;
1816   /* Path to most derived.  */
1817   VEC(tree,heap) *path;
1818 } find_final_overrider_data;
1819
1820 /* Add the overrider along the current path to FFOD->CANDIDATES.
1821    Returns true if an overrider was found; false otherwise.  */
1822
1823 static bool
1824 dfs_find_final_overrider_1 (tree binfo,
1825                             find_final_overrider_data *ffod,
1826                             unsigned depth)
1827 {
1828   tree method;
1829
1830   /* If BINFO is not the most derived type, try a more derived class.
1831      A definition there will overrider a definition here.  */
1832   if (depth)
1833     {
1834       depth--;
1835       if (dfs_find_final_overrider_1
1836           (VEC_index (tree, ffod->path, depth), ffod, depth))
1837         return true;
1838     }
1839
1840   method = look_for_overrides_here (BINFO_TYPE (binfo), ffod->fn);
1841   if (method)
1842     {
1843       tree *candidate = &ffod->candidates;
1844
1845       /* Remove any candidates overridden by this new function.  */
1846       while (*candidate)
1847         {
1848           /* If *CANDIDATE overrides METHOD, then METHOD
1849              cannot override anything else on the list.  */
1850           if (base_derived_from (TREE_VALUE (*candidate), binfo))
1851             return true;
1852           /* If METHOD overrides *CANDIDATE, remove *CANDIDATE.  */
1853           if (base_derived_from (binfo, TREE_VALUE (*candidate)))
1854             *candidate = TREE_CHAIN (*candidate);
1855           else
1856             candidate = &TREE_CHAIN (*candidate);
1857         }
1858
1859       /* Add the new function.  */
1860       ffod->candidates = tree_cons (method, binfo, ffod->candidates);
1861       return true;
1862     }
1863
1864   return false;
1865 }
1866
1867 /* Called from find_final_overrider via dfs_walk.  */
1868
1869 static tree
1870 dfs_find_final_overrider_pre (tree binfo, void *data)
1871 {
1872   find_final_overrider_data *ffod = (find_final_overrider_data *) data;
1873
1874   if (binfo == ffod->declaring_base)
1875     dfs_find_final_overrider_1 (binfo, ffod, VEC_length (tree, ffod->path));
1876   VEC_safe_push (tree, heap, ffod->path, binfo);
1877
1878   return NULL_TREE;
1879 }
1880
1881 static tree
1882 dfs_find_final_overrider_post (tree binfo ATTRIBUTE_UNUSED, void *data)
1883 {
1884   find_final_overrider_data *ffod = (find_final_overrider_data *) data;
1885   VEC_pop (tree, ffod->path);
1886
1887   return NULL_TREE;
1888 }
1889
1890 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
1891    FN and whose TREE_VALUE is the binfo for the base where the
1892    overriding occurs.  BINFO (in the hierarchy dominated by the binfo
1893    DERIVED) is the base object in which FN is declared.  */
1894
1895 static tree
1896 find_final_overrider (tree derived, tree binfo, tree fn)
1897 {
1898   find_final_overrider_data ffod;
1899
1900   /* Getting this right is a little tricky.  This is valid:
1901
1902        struct S { virtual void f (); };
1903        struct T { virtual void f (); };
1904        struct U : public S, public T { };
1905
1906      even though calling `f' in `U' is ambiguous.  But,
1907
1908        struct R { virtual void f(); };
1909        struct S : virtual public R { virtual void f (); };
1910        struct T : virtual public R { virtual void f (); };
1911        struct U : public S, public T { };
1912
1913      is not -- there's no way to decide whether to put `S::f' or
1914      `T::f' in the vtable for `R'.
1915
1916      The solution is to look at all paths to BINFO.  If we find
1917      different overriders along any two, then there is a problem.  */
1918   if (DECL_THUNK_P (fn))
1919     fn = THUNK_TARGET (fn);
1920
1921   /* Determine the depth of the hierarchy.  */
1922   ffod.fn = fn;
1923   ffod.declaring_base = binfo;
1924   ffod.candidates = NULL_TREE;
1925   ffod.path = VEC_alloc (tree, heap, 30);
1926
1927   dfs_walk_all (derived, dfs_find_final_overrider_pre,
1928                 dfs_find_final_overrider_post, &ffod);
1929
1930   VEC_free (tree, heap, ffod.path);
1931
1932   /* If there was no winner, issue an error message.  */
1933   if (!ffod.candidates || TREE_CHAIN (ffod.candidates))
1934     return error_mark_node;
1935
1936   return ffod.candidates;
1937 }
1938
1939 /* Return the index of the vcall offset for FN when TYPE is used as a
1940    virtual base.  */
1941
1942 static tree
1943 get_vcall_index (tree fn, tree type)
1944 {
1945   VEC(tree_pair_s,gc) *indices = CLASSTYPE_VCALL_INDICES (type);
1946   tree_pair_p p;
1947   unsigned ix;
1948
1949   for (ix = 0; VEC_iterate (tree_pair_s, indices, ix, p); ix++)
1950     if ((DECL_DESTRUCTOR_P (fn) && DECL_DESTRUCTOR_P (p->purpose))
1951         || same_signature_p (fn, p->purpose))
1952       return p->value;
1953
1954   /* There should always be an appropriate index.  */
1955   gcc_unreachable ();
1956 }
1957
1958 /* Update an entry in the vtable for BINFO, which is in the hierarchy
1959    dominated by T.  FN has been overridden in BINFO; VIRTUALS points to the
1960    corresponding position in the BINFO_VIRTUALS list.  */
1961
1962 static void
1963 update_vtable_entry_for_fn (tree t, tree binfo, tree fn, tree* virtuals,
1964                             unsigned ix)
1965 {
1966   tree b;
1967   tree overrider;
1968   tree delta;
1969   tree virtual_base;
1970   tree first_defn;
1971   tree overrider_fn, overrider_target;
1972   tree target_fn = DECL_THUNK_P (fn) ? THUNK_TARGET (fn) : fn;
1973   tree over_return, base_return;
1974   bool lost = false;
1975
1976   /* Find the nearest primary base (possibly binfo itself) which defines
1977      this function; this is the class the caller will convert to when
1978      calling FN through BINFO.  */
1979   for (b = binfo; ; b = get_primary_binfo (b))
1980     {
1981       gcc_assert (b);
1982       if (look_for_overrides_here (BINFO_TYPE (b), target_fn))
1983         break;
1984
1985       /* The nearest definition is from a lost primary.  */
1986       if (BINFO_LOST_PRIMARY_P (b))
1987         lost = true;
1988     }
1989   first_defn = b;
1990
1991   /* Find the final overrider.  */
1992   overrider = find_final_overrider (TYPE_BINFO (t), b, target_fn);
1993   if (overrider == error_mark_node)
1994     {
1995       error ("no unique final overrider for %qD in %qT", target_fn, t);
1996       return;
1997     }
1998   overrider_target = overrider_fn = TREE_PURPOSE (overrider);
1999
2000   /* Check for adjusting covariant return types.  */
2001   over_return = TREE_TYPE (TREE_TYPE (overrider_target));
2002   base_return = TREE_TYPE (TREE_TYPE (target_fn));
2003
2004   if (POINTER_TYPE_P (over_return)
2005       && TREE_CODE (over_return) == TREE_CODE (base_return)
2006       && CLASS_TYPE_P (TREE_TYPE (over_return))
2007       && CLASS_TYPE_P (TREE_TYPE (base_return))
2008       /* If the overrider is invalid, don't even try.  */
2009       && !DECL_INVALID_OVERRIDER_P (overrider_target))
2010     {
2011       /* If FN is a covariant thunk, we must figure out the adjustment
2012          to the final base FN was converting to. As OVERRIDER_TARGET might
2013          also be converting to the return type of FN, we have to
2014          combine the two conversions here.  */
2015       tree fixed_offset, virtual_offset;
2016
2017       over_return = TREE_TYPE (over_return);
2018       base_return = TREE_TYPE (base_return);
2019
2020       if (DECL_THUNK_P (fn))
2021         {
2022           gcc_assert (DECL_RESULT_THUNK_P (fn));
2023           fixed_offset = ssize_int (THUNK_FIXED_OFFSET (fn));
2024           virtual_offset = THUNK_VIRTUAL_OFFSET (fn);
2025         }
2026       else
2027         fixed_offset = virtual_offset = NULL_TREE;
2028
2029       if (virtual_offset)
2030         /* Find the equivalent binfo within the return type of the
2031            overriding function. We will want the vbase offset from
2032            there.  */
2033         virtual_offset = binfo_for_vbase (BINFO_TYPE (virtual_offset),
2034                                           over_return);
2035       else if (!same_type_ignoring_top_level_qualifiers_p
2036                (over_return, base_return))
2037         {
2038           /* There was no existing virtual thunk (which takes
2039              precedence).  So find the binfo of the base function's
2040              return type within the overriding function's return type.
2041              We cannot call lookup base here, because we're inside a
2042              dfs_walk, and will therefore clobber the BINFO_MARKED
2043              flags.  Fortunately we know the covariancy is valid (it
2044              has already been checked), so we can just iterate along
2045              the binfos, which have been chained in inheritance graph
2046              order.  Of course it is lame that we have to repeat the
2047              search here anyway -- we should really be caching pieces
2048              of the vtable and avoiding this repeated work.  */
2049           tree thunk_binfo, base_binfo;
2050
2051           /* Find the base binfo within the overriding function's
2052              return type.  We will always find a thunk_binfo, except
2053              when the covariancy is invalid (which we will have
2054              already diagnosed).  */
2055           for (base_binfo = TYPE_BINFO (base_return),
2056                thunk_binfo = TYPE_BINFO (over_return);
2057                thunk_binfo;
2058                thunk_binfo = TREE_CHAIN (thunk_binfo))
2059             if (SAME_BINFO_TYPE_P (BINFO_TYPE (thunk_binfo),
2060                                    BINFO_TYPE (base_binfo)))
2061               break;
2062
2063           /* See if virtual inheritance is involved.  */
2064           for (virtual_offset = thunk_binfo;
2065                virtual_offset;
2066                virtual_offset = BINFO_INHERITANCE_CHAIN (virtual_offset))
2067             if (BINFO_VIRTUAL_P (virtual_offset))
2068               break;
2069
2070           if (virtual_offset
2071               || (thunk_binfo && !BINFO_OFFSET_ZEROP (thunk_binfo)))
2072             {
2073               tree offset = convert (ssizetype, BINFO_OFFSET (thunk_binfo));
2074
2075               if (virtual_offset)
2076                 {
2077                   /* We convert via virtual base.  Adjust the fixed
2078                      offset to be from there.  */
2079                   offset = size_diffop
2080                     (offset, convert
2081                      (ssizetype, BINFO_OFFSET (virtual_offset)));
2082                 }
2083               if (fixed_offset)
2084                 /* There was an existing fixed offset, this must be
2085                    from the base just converted to, and the base the
2086                    FN was thunking to.  */
2087                 fixed_offset = size_binop (PLUS_EXPR, fixed_offset, offset);
2088               else
2089                 fixed_offset = offset;
2090             }
2091         }
2092
2093       if (fixed_offset || virtual_offset)
2094         /* Replace the overriding function with a covariant thunk.  We
2095            will emit the overriding function in its own slot as
2096            well.  */
2097         overrider_fn = make_thunk (overrider_target, /*this_adjusting=*/0,
2098                                    fixed_offset, virtual_offset);
2099     }
2100   else
2101     gcc_assert (DECL_INVALID_OVERRIDER_P (overrider_target) ||
2102                 !DECL_THUNK_P (fn));
2103
2104   /* Assume that we will produce a thunk that convert all the way to
2105      the final overrider, and not to an intermediate virtual base.  */
2106   virtual_base = NULL_TREE;
2107
2108   /* See if we can convert to an intermediate virtual base first, and then
2109      use the vcall offset located there to finish the conversion.  */
2110   for (; b; b = BINFO_INHERITANCE_CHAIN (b))
2111     {
2112       /* If we find the final overrider, then we can stop
2113          walking.  */
2114       if (SAME_BINFO_TYPE_P (BINFO_TYPE (b),
2115                              BINFO_TYPE (TREE_VALUE (overrider))))
2116         break;
2117
2118       /* If we find a virtual base, and we haven't yet found the
2119          overrider, then there is a virtual base between the
2120          declaring base (first_defn) and the final overrider.  */
2121       if (BINFO_VIRTUAL_P (b))
2122         {
2123           virtual_base = b;
2124           break;
2125         }
2126     }
2127
2128   if (overrider_fn != overrider_target && !virtual_base)
2129     {
2130       /* The ABI specifies that a covariant thunk includes a mangling
2131          for a this pointer adjustment.  This-adjusting thunks that
2132          override a function from a virtual base have a vcall
2133          adjustment.  When the virtual base in question is a primary
2134          virtual base, we know the adjustments are zero, (and in the
2135          non-covariant case, we would not use the thunk).
2136          Unfortunately we didn't notice this could happen, when
2137          designing the ABI and so never mandated that such a covariant
2138          thunk should be emitted.  Because we must use the ABI mandated
2139          name, we must continue searching from the binfo where we
2140          found the most recent definition of the function, towards the
2141          primary binfo which first introduced the function into the
2142          vtable.  If that enters a virtual base, we must use a vcall
2143          this-adjusting thunk.  Bleah! */
2144       tree probe = first_defn;
2145
2146       while ((probe = get_primary_binfo (probe))
2147              && (unsigned) list_length (BINFO_VIRTUALS (probe)) > ix)
2148         if (BINFO_VIRTUAL_P (probe))
2149           virtual_base = probe;
2150
2151       if (virtual_base)
2152         /* Even if we find a virtual base, the correct delta is
2153            between the overrider and the binfo we're building a vtable
2154            for.  */
2155         goto virtual_covariant;
2156     }
2157
2158   /* Compute the constant adjustment to the `this' pointer.  The
2159      `this' pointer, when this function is called, will point at BINFO
2160      (or one of its primary bases, which are at the same offset).  */
2161   if (virtual_base)
2162     /* The `this' pointer needs to be adjusted from the declaration to
2163        the nearest virtual base.  */
2164     delta = size_diffop (convert (ssizetype, BINFO_OFFSET (virtual_base)),
2165                          convert (ssizetype, BINFO_OFFSET (first_defn)));
2166   else if (lost)
2167     /* If the nearest definition is in a lost primary, we don't need an
2168        entry in our vtable.  Except possibly in a constructor vtable,
2169        if we happen to get our primary back.  In that case, the offset
2170        will be zero, as it will be a primary base.  */
2171     delta = size_zero_node;
2172   else
2173     /* The `this' pointer needs to be adjusted from pointing to
2174        BINFO to pointing at the base where the final overrider
2175        appears.  */
2176     virtual_covariant:
2177     delta = size_diffop (convert (ssizetype,
2178                                   BINFO_OFFSET (TREE_VALUE (overrider))),
2179                          convert (ssizetype, BINFO_OFFSET (binfo)));
2180
2181   modify_vtable_entry (t, binfo, overrider_fn, delta, virtuals);
2182
2183   if (virtual_base)
2184     BV_VCALL_INDEX (*virtuals)
2185       = get_vcall_index (overrider_target, BINFO_TYPE (virtual_base));
2186   else
2187     BV_VCALL_INDEX (*virtuals) = NULL_TREE;
2188 }
2189
2190 /* Called from modify_all_vtables via dfs_walk.  */
2191
2192 static tree
2193 dfs_modify_vtables (tree binfo, void* data)
2194 {
2195   tree t = (tree) data;
2196   tree virtuals;
2197   tree old_virtuals;
2198   unsigned ix;
2199
2200   if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
2201     /* A base without a vtable needs no modification, and its bases
2202        are uninteresting.  */
2203     return dfs_skip_bases;
2204
2205   if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t)
2206       && !CLASSTYPE_HAS_PRIMARY_BASE_P (t))
2207     /* Don't do the primary vtable, if it's new.  */
2208     return NULL_TREE;
2209
2210   if (BINFO_PRIMARY_P (binfo) && !BINFO_VIRTUAL_P (binfo))
2211     /* There's no need to modify the vtable for a non-virtual primary
2212        base; we're not going to use that vtable anyhow.  We do still
2213        need to do this for virtual primary bases, as they could become
2214        non-primary in a construction vtable.  */
2215     return NULL_TREE;
2216
2217   make_new_vtable (t, binfo);
2218
2219   /* Now, go through each of the virtual functions in the virtual
2220      function table for BINFO.  Find the final overrider, and update
2221      the BINFO_VIRTUALS list appropriately.  */
2222   for (ix = 0, virtuals = BINFO_VIRTUALS (binfo),
2223          old_virtuals = BINFO_VIRTUALS (TYPE_BINFO (BINFO_TYPE (binfo)));
2224        virtuals;
2225        ix++, virtuals = TREE_CHAIN (virtuals),
2226          old_virtuals = TREE_CHAIN (old_virtuals))
2227     update_vtable_entry_for_fn (t,
2228                                 binfo,
2229                                 BV_FN (old_virtuals),
2230                                 &virtuals, ix);
2231
2232   return NULL_TREE;
2233 }
2234
2235 /* Update all of the primary and secondary vtables for T.  Create new
2236    vtables as required, and initialize their RTTI information.  Each
2237    of the functions in VIRTUALS is declared in T and may override a
2238    virtual function from a base class; find and modify the appropriate
2239    entries to point to the overriding functions.  Returns a list, in
2240    declaration order, of the virtual functions that are declared in T,
2241    but do not appear in the primary base class vtable, and which
2242    should therefore be appended to the end of the vtable for T.  */
2243
2244 static tree
2245 modify_all_vtables (tree t, tree virtuals)
2246 {
2247   tree binfo = TYPE_BINFO (t);
2248   tree *fnsp;
2249
2250   /* Update all of the vtables.  */
2251   dfs_walk_once (binfo, dfs_modify_vtables, NULL, t);
2252
2253   /* Add virtual functions not already in our primary vtable. These
2254      will be both those introduced by this class, and those overridden
2255      from secondary bases.  It does not include virtuals merely
2256      inherited from secondary bases.  */
2257   for (fnsp = &virtuals; *fnsp; )
2258     {
2259       tree fn = TREE_VALUE (*fnsp);
2260
2261       if (!value_member (fn, BINFO_VIRTUALS (binfo))
2262           || DECL_VINDEX (fn) == error_mark_node)
2263         {
2264           /* We don't need to adjust the `this' pointer when
2265              calling this function.  */
2266           BV_DELTA (*fnsp) = integer_zero_node;
2267           BV_VCALL_INDEX (*fnsp) = NULL_TREE;
2268
2269           /* This is a function not already in our vtable.  Keep it.  */
2270           fnsp = &TREE_CHAIN (*fnsp);
2271         }
2272       else
2273         /* We've already got an entry for this function.  Skip it.  */
2274         *fnsp = TREE_CHAIN (*fnsp);
2275     }
2276
2277   return virtuals;
2278 }
2279
2280 /* Get the base virtual function declarations in T that have the
2281    indicated NAME.  */
2282
2283 static tree
2284 get_basefndecls (tree name, tree t)
2285 {
2286   tree methods;
2287   tree base_fndecls = NULL_TREE;
2288   int n_baseclasses = BINFO_N_BASE_BINFOS (TYPE_BINFO (t));
2289   int i;
2290
2291   /* Find virtual functions in T with the indicated NAME.  */
2292   i = lookup_fnfields_1 (t, name);
2293   if (i != -1)
2294     for (methods = VEC_index (tree, CLASSTYPE_METHOD_VEC (t), i);
2295          methods;
2296          methods = OVL_NEXT (methods))
2297       {
2298         tree method = OVL_CURRENT (methods);
2299
2300         if (TREE_CODE (method) == FUNCTION_DECL
2301             && DECL_VINDEX (method))
2302           base_fndecls = tree_cons (NULL_TREE, method, base_fndecls);
2303       }
2304
2305   if (base_fndecls)
2306     return base_fndecls;
2307
2308   for (i = 0; i < n_baseclasses; i++)
2309     {
2310       tree basetype = BINFO_TYPE (BINFO_BASE_BINFO (TYPE_BINFO (t), i));
2311       base_fndecls = chainon (get_basefndecls (name, basetype),
2312                               base_fndecls);
2313     }
2314
2315   return base_fndecls;
2316 }
2317
2318 /* If this declaration supersedes the declaration of
2319    a method declared virtual in the base class, then
2320    mark this field as being virtual as well.  */
2321
2322 void
2323 check_for_override (tree decl, tree ctype)
2324 {
2325   if (TREE_CODE (decl) == TEMPLATE_DECL)
2326     /* In [temp.mem] we have:
2327
2328          A specialization of a member function template does not
2329          override a virtual function from a base class.  */
2330     return;
2331   if ((DECL_DESTRUCTOR_P (decl)
2332        || IDENTIFIER_VIRTUAL_P (DECL_NAME (decl))
2333        || DECL_CONV_FN_P (decl))
2334       && look_for_overrides (ctype, decl)
2335       && !DECL_STATIC_FUNCTION_P (decl))
2336     /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2337        the error_mark_node so that we know it is an overriding
2338        function.  */
2339     DECL_VINDEX (decl) = decl;
2340
2341   if (DECL_VIRTUAL_P (decl))
2342     {
2343       if (!DECL_VINDEX (decl))
2344         DECL_VINDEX (decl) = error_mark_node;
2345       IDENTIFIER_VIRTUAL_P (DECL_NAME (decl)) = 1;
2346       if (DECL_DLLIMPORT_P (decl))
2347         {
2348           /* When we handled the dllimport attribute we may not have known
2349              that this function is virtual   We can't use dllimport
2350              semantics for a virtual method because we need to initialize
2351              the vtable entry with a constant address.  */
2352           DECL_DLLIMPORT_P (decl) = 0;
2353           DECL_ATTRIBUTES (decl)
2354             = remove_attribute ("dllimport", DECL_ATTRIBUTES (decl));
2355         }
2356     }
2357 }
2358
2359 /* Warn about hidden virtual functions that are not overridden in t.
2360    We know that constructors and destructors don't apply.  */
2361
2362 static void
2363 warn_hidden (tree t)
2364 {
2365   VEC(tree,gc) *method_vec = CLASSTYPE_METHOD_VEC (t);
2366   tree fns;
2367   size_t i;
2368
2369   /* We go through each separately named virtual function.  */
2370   for (i = CLASSTYPE_FIRST_CONVERSION_SLOT;
2371        VEC_iterate (tree, method_vec, i, fns);
2372        ++i)
2373     {
2374       tree fn;
2375       tree name;
2376       tree fndecl;
2377       tree base_fndecls;
2378       tree base_binfo;
2379       tree binfo;
2380       int j;
2381
2382       /* All functions in this slot in the CLASSTYPE_METHOD_VEC will
2383          have the same name.  Figure out what name that is.  */
2384       name = DECL_NAME (OVL_CURRENT (fns));
2385       /* There are no possibly hidden functions yet.  */
2386       base_fndecls = NULL_TREE;
2387       /* Iterate through all of the base classes looking for possibly
2388          hidden functions.  */
2389       for (binfo = TYPE_BINFO (t), j = 0;
2390            BINFO_BASE_ITERATE (binfo, j, base_binfo); j++)
2391         {
2392           tree basetype = BINFO_TYPE (base_binfo);
2393           base_fndecls = chainon (get_basefndecls (name, basetype),
2394                                   base_fndecls);
2395         }
2396
2397       /* If there are no functions to hide, continue.  */
2398       if (!base_fndecls)
2399         continue;
2400
2401       /* Remove any overridden functions.  */
2402       for (fn = fns; fn; fn = OVL_NEXT (fn))
2403         {
2404           fndecl = OVL_CURRENT (fn);
2405           if (DECL_VINDEX (fndecl))
2406             {
2407               tree *prev = &base_fndecls;
2408
2409               while (*prev)
2410                 /* If the method from the base class has the same
2411                    signature as the method from the derived class, it
2412                    has been overridden.  */
2413                 if (same_signature_p (fndecl, TREE_VALUE (*prev)))
2414                   *prev = TREE_CHAIN (*prev);
2415                 else
2416                   prev = &TREE_CHAIN (*prev);
2417             }
2418         }
2419
2420       /* Now give a warning for all base functions without overriders,
2421          as they are hidden.  */
2422       while (base_fndecls)
2423         {
2424           /* Here we know it is a hider, and no overrider exists.  */
2425           warning (OPT_Woverloaded_virtual, "%q+D was hidden", TREE_VALUE (base_fndecls));
2426           warning (OPT_Woverloaded_virtual, "  by %q+D", fns);
2427           base_fndecls = TREE_CHAIN (base_fndecls);
2428         }
2429     }
2430 }
2431
2432 /* Check for things that are invalid.  There are probably plenty of other
2433    things we should check for also.  */
2434
2435 static void
2436 finish_struct_anon (tree t)
2437 {
2438   tree field;
2439
2440   for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
2441     {
2442       if (TREE_STATIC (field))
2443         continue;
2444       if (TREE_CODE (field) != FIELD_DECL)
2445         continue;
2446
2447       if (DECL_NAME (field) == NULL_TREE
2448           && ANON_AGGR_TYPE_P (TREE_TYPE (field)))
2449         {
2450           tree elt = TYPE_FIELDS (TREE_TYPE (field));
2451           for (; elt; elt = TREE_CHAIN (elt))
2452             {
2453               /* We're generally only interested in entities the user
2454                  declared, but we also find nested classes by noticing
2455                  the TYPE_DECL that we create implicitly.  You're
2456                  allowed to put one anonymous union inside another,
2457                  though, so we explicitly tolerate that.  We use
2458                  TYPE_ANONYMOUS_P rather than ANON_AGGR_TYPE_P so that
2459                  we also allow unnamed types used for defining fields.  */
2460               if (DECL_ARTIFICIAL (elt)
2461                   && (!DECL_IMPLICIT_TYPEDEF_P (elt)
2462                       || TYPE_ANONYMOUS_P (TREE_TYPE (elt))))
2463                 continue;
2464
2465               if (TREE_CODE (elt) != FIELD_DECL)
2466                 {
2467                   pedwarn ("%q+#D invalid; an anonymous union can "
2468                            "only have non-static data members", elt);
2469                   continue;
2470                 }
2471
2472               if (TREE_PRIVATE (elt))
2473                 pedwarn ("private member %q+#D in anonymous union", elt);
2474               else if (TREE_PROTECTED (elt))
2475                 pedwarn ("protected member %q+#D in anonymous union", elt);
2476
2477               TREE_PRIVATE (elt) = TREE_PRIVATE (field);
2478               TREE_PROTECTED (elt) = TREE_PROTECTED (field);
2479             }
2480         }
2481     }
2482 }
2483
2484 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2485    will be used later during class template instantiation.
2486    When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2487    a non-static member data (FIELD_DECL), a member function
2488    (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2489    a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2490    When FRIEND_P is nonzero, T is either a friend class
2491    (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2492    (FUNCTION_DECL, TEMPLATE_DECL).  */
2493
2494 void
2495 maybe_add_class_template_decl_list (tree type, tree t, int friend_p)
2496 {
2497   /* Save some memory by not creating TREE_LIST if TYPE is not template.  */
2498   if (CLASSTYPE_TEMPLATE_INFO (type))
2499     CLASSTYPE_DECL_LIST (type)
2500       = tree_cons (friend_p ? NULL_TREE : type,
2501                    t, CLASSTYPE_DECL_LIST (type));
2502 }
2503
2504 /* Create default constructors, assignment operators, and so forth for
2505    the type indicated by T, if they are needed.  CANT_HAVE_CONST_CTOR,
2506    and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
2507    the class cannot have a default constructor, copy constructor
2508    taking a const reference argument, or an assignment operator taking
2509    a const reference, respectively.  */
2510
2511 static void
2512 add_implicitly_declared_members (tree t,
2513                                  int cant_have_const_cctor,
2514                                  int cant_have_const_assignment)
2515 {
2516   /* Destructor.  */
2517   if (!CLASSTYPE_DESTRUCTORS (t))
2518     {
2519       /* In general, we create destructors lazily.  */
2520       CLASSTYPE_LAZY_DESTRUCTOR (t) = 1;
2521       /* However, if the implicit destructor is non-trivial
2522          destructor, we sometimes have to create it at this point.  */
2523       if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t))
2524         {
2525           bool lazy_p = true;
2526
2527           if (TYPE_FOR_JAVA (t))
2528             /* If this a Java class, any non-trivial destructor is
2529                invalid, even if compiler-generated.  Therefore, if the
2530                destructor is non-trivial we create it now.  */
2531             lazy_p = false;
2532           else
2533             {
2534               tree binfo;
2535               tree base_binfo;
2536               int ix;
2537
2538               /* If the implicit destructor will be virtual, then we must
2539                  generate it now because (unfortunately) we do not
2540                  generate virtual tables lazily.  */
2541               binfo = TYPE_BINFO (t);
2542               for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++)
2543                 {
2544                   tree base_type;
2545                   tree dtor;
2546
2547                   base_type = BINFO_TYPE (base_binfo);
2548                   dtor = CLASSTYPE_DESTRUCTORS (base_type);
2549                   if (dtor && DECL_VIRTUAL_P (dtor))
2550                     {
2551                       lazy_p = false;
2552                       break;
2553                     }
2554                 }
2555             }
2556
2557           /* If we can't get away with being lazy, generate the destructor
2558              now.  */
2559           if (!lazy_p)
2560             lazily_declare_fn (sfk_destructor, t);
2561         }
2562     }
2563
2564   /* Default constructor.  */
2565   if (! TYPE_HAS_CONSTRUCTOR (t))
2566     {
2567       TYPE_HAS_DEFAULT_CONSTRUCTOR (t) = 1;
2568       CLASSTYPE_LAZY_DEFAULT_CTOR (t) = 1;
2569     }
2570
2571   /* Copy constructor.  */
2572   if (! TYPE_HAS_INIT_REF (t) && ! TYPE_FOR_JAVA (t))
2573     {
2574       TYPE_HAS_INIT_REF (t) = 1;
2575       TYPE_HAS_CONST_INIT_REF (t) = !cant_have_const_cctor;
2576       CLASSTYPE_LAZY_COPY_CTOR (t) = 1;
2577       TYPE_HAS_CONSTRUCTOR (t) = 1;
2578     }
2579
2580   /* If there is no assignment operator, one will be created if and
2581      when it is needed.  For now, just record whether or not the type
2582      of the parameter to the assignment operator will be a const or
2583      non-const reference.  */
2584   if (!TYPE_HAS_ASSIGN_REF (t) && !TYPE_FOR_JAVA (t))
2585     {
2586       TYPE_HAS_ASSIGN_REF (t) = 1;
2587       TYPE_HAS_CONST_ASSIGN_REF (t) = !cant_have_const_assignment;
2588       CLASSTYPE_LAZY_ASSIGNMENT_OP (t) = 1;
2589     }
2590 }
2591
2592 /* Subroutine of finish_struct_1.  Recursively count the number of fields
2593    in TYPE, including anonymous union members.  */
2594
2595 static int
2596 count_fields (tree fields)
2597 {
2598   tree x;
2599   int n_fields = 0;
2600   for (x = fields; x; x = TREE_CHAIN (x))
2601     {
2602       if (TREE_CODE (x) == FIELD_DECL && ANON_AGGR_TYPE_P (TREE_TYPE (x)))
2603         n_fields += count_fields (TYPE_FIELDS (TREE_TYPE (x)));
2604       else
2605         n_fields += 1;
2606     }
2607   return n_fields;
2608 }
2609
2610 /* Subroutine of finish_struct_1.  Recursively add all the fields in the
2611    TREE_LIST FIELDS to the SORTED_FIELDS_TYPE elts, starting at offset IDX.  */
2612
2613 static int
2614 add_fields_to_record_type (tree fields, struct sorted_fields_type *field_vec, int idx)
2615 {
2616   tree x;
2617   for (x = fields; x; x = TREE_CHAIN (x))
2618     {
2619       if (TREE_CODE (x) == FIELD_DECL && ANON_AGGR_TYPE_P (TREE_TYPE (x)))
2620         idx = add_fields_to_record_type (TYPE_FIELDS (TREE_TYPE (x)), field_vec, idx);
2621       else
2622         field_vec->elts[idx++] = x;
2623     }
2624   return idx;
2625 }
2626
2627 /* FIELD is a bit-field.  We are finishing the processing for its
2628    enclosing type.  Issue any appropriate messages and set appropriate
2629    flags.  */
2630
2631 static void
2632 check_bitfield_decl (tree field)
2633 {
2634   tree type = TREE_TYPE (field);
2635   tree w;
2636
2637   /* Extract the declared width of the bitfield, which has been
2638      temporarily stashed in DECL_INITIAL.  */
2639   w = DECL_INITIAL (field);
2640   gcc_assert (w != NULL_TREE);
2641   /* Remove the bit-field width indicator so that the rest of the
2642      compiler does not treat that value as an initializer.  */
2643   DECL_INITIAL (field) = NULL_TREE;
2644
2645   /* Detect invalid bit-field type.  */
2646   if (!INTEGRAL_TYPE_P (type))
2647     {
2648       error ("bit-field %q+#D with non-integral type", field);
2649       TREE_TYPE (field) = error_mark_node;
2650       w = error_mark_node;
2651     }
2652   else
2653     {
2654       /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs.  */
2655       STRIP_NOPS (w);
2656
2657       /* detect invalid field size.  */
2658       w = integral_constant_value (w);
2659
2660       if (TREE_CODE (w) != INTEGER_CST)
2661         {
2662           error ("bit-field %q+D width not an integer constant", field);
2663           w = error_mark_node;
2664         }
2665       else if (tree_int_cst_sgn (w) < 0)
2666         {
2667           error ("negative width in bit-field %q+D", field);
2668           w = error_mark_node;
2669         }
2670       else if (integer_zerop (w) && DECL_NAME (field) != 0)
2671         {
2672           error ("zero width for bit-field %q+D", field);
2673           w = error_mark_node;
2674         }
2675       else if (compare_tree_int (w, TYPE_PRECISION (type)) > 0
2676                && TREE_CODE (type) != ENUMERAL_TYPE
2677                && TREE_CODE (type) != BOOLEAN_TYPE)
2678         warning (0, "width of %q+D exceeds its type", field);
2679       else if (TREE_CODE (type) == ENUMERAL_TYPE
2680                && (0 > compare_tree_int (w,
2681                                          min_precision (TYPE_MIN_VALUE (type),
2682                                                         TYPE_UNSIGNED (type)))
2683                    ||  0 > compare_tree_int (w,
2684                                              min_precision
2685                                              (TYPE_MAX_VALUE (type),
2686                                               TYPE_UNSIGNED (type)))))
2687         warning (0, "%q+D is too small to hold all values of %q#T", field, type);
2688     }
2689
2690   if (w != error_mark_node)
2691     {
2692       DECL_SIZE (field) = convert (bitsizetype, w);
2693       DECL_BIT_FIELD (field) = 1;
2694     }
2695   else
2696     {
2697       /* Non-bit-fields are aligned for their type.  */
2698       DECL_BIT_FIELD (field) = 0;
2699       CLEAR_DECL_C_BIT_FIELD (field);
2700     }
2701 }
2702
2703 /* FIELD is a non bit-field.  We are finishing the processing for its
2704    enclosing type T.  Issue any appropriate messages and set appropriate
2705    flags.  */
2706
2707 static void
2708 check_field_decl (tree field,
2709                   tree t,
2710                   int* cant_have_const_ctor,
2711                   int* no_const_asn_ref,
2712                   int* any_default_members)
2713 {
2714   tree type = strip_array_types (TREE_TYPE (field));
2715
2716   /* An anonymous union cannot contain any fields which would change
2717      the settings of CANT_HAVE_CONST_CTOR and friends.  */
2718   if (ANON_UNION_TYPE_P (type))
2719     ;
2720   /* And, we don't set TYPE_HAS_CONST_INIT_REF, etc., for anonymous
2721      structs.  So, we recurse through their fields here.  */
2722   else if (ANON_AGGR_TYPE_P (type))
2723     {
2724       tree fields;
2725
2726       for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields))
2727         if (TREE_CODE (fields) == FIELD_DECL && !DECL_C_BIT_FIELD (field))
2728           check_field_decl (fields, t, cant_have_const_ctor,
2729                             no_const_asn_ref, any_default_members);
2730     }
2731   /* Check members with class type for constructors, destructors,
2732      etc.  */
2733   else if (CLASS_TYPE_P (type))
2734     {
2735       /* Never let anything with uninheritable virtuals
2736          make it through without complaint.  */
2737       abstract_virtuals_error (field, type);
2738
2739       if (TREE_CODE (t) == UNION_TYPE)
2740         {
2741           if (TYPE_NEEDS_CONSTRUCTING (type))
2742             error ("member %q+#D with constructor not allowed in union",
2743                    field);
2744           if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
2745             error ("member %q+#D with destructor not allowed in union", field);
2746           if (TYPE_HAS_COMPLEX_ASSIGN_REF (type))
2747             error ("member %q+#D with copy assignment operator not allowed in union",
2748                    field);
2749         }
2750       else
2751         {
2752           TYPE_NEEDS_CONSTRUCTING (t) |= TYPE_NEEDS_CONSTRUCTING (type);
2753           TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
2754             |= TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type);
2755           TYPE_HAS_COMPLEX_ASSIGN_REF (t) |= TYPE_HAS_COMPLEX_ASSIGN_REF (type);
2756           TYPE_HAS_COMPLEX_INIT_REF (t) |= TYPE_HAS_COMPLEX_INIT_REF (type);
2757           TYPE_HAS_COMPLEX_DFLT (t) |= TYPE_HAS_COMPLEX_DFLT (type);
2758         }
2759
2760       if (!TYPE_HAS_CONST_INIT_REF (type))
2761         *cant_have_const_ctor = 1;
2762
2763       if (!TYPE_HAS_CONST_ASSIGN_REF (type))
2764         *no_const_asn_ref = 1;
2765     }
2766   if (DECL_INITIAL (field) != NULL_TREE)
2767     {
2768       /* `build_class_init_list' does not recognize
2769          non-FIELD_DECLs.  */
2770       if (TREE_CODE (t) == UNION_TYPE && any_default_members != 0)
2771         error ("multiple fields in union %qT initialized", t);
2772       *any_default_members = 1;
2773     }
2774 }
2775
2776 /* Check the data members (both static and non-static), class-scoped
2777    typedefs, etc., appearing in the declaration of T.  Issue
2778    appropriate diagnostics.  Sets ACCESS_DECLS to a list (in
2779    declaration order) of access declarations; each TREE_VALUE in this
2780    list is a USING_DECL.
2781
2782    In addition, set the following flags:
2783
2784      EMPTY_P
2785        The class is empty, i.e., contains no non-static data members.
2786
2787      CANT_HAVE_CONST_CTOR_P
2788        This class cannot have an implicitly generated copy constructor
2789        taking a const reference.
2790
2791      CANT_HAVE_CONST_ASN_REF
2792        This class cannot have an implicitly generated assignment
2793        operator taking a const reference.
2794
2795    All of these flags should be initialized before calling this
2796    function.
2797
2798    Returns a pointer to the end of the TYPE_FIELDs chain; additional
2799    fields can be added by adding to this chain.  */
2800
2801 static void
2802 check_field_decls (tree t, tree *access_decls,
2803                    int *cant_have_const_ctor_p,
2804                    int *no_const_asn_ref_p)
2805 {
2806   tree *field;
2807   tree *next;
2808   bool has_pointers;
2809   int any_default_members;
2810   int cant_pack = 0;
2811
2812   /* Assume there are no access declarations.  */
2813   *access_decls = NULL_TREE;
2814   /* Assume this class has no pointer members.  */
2815   has_pointers = false;
2816   /* Assume none of the members of this class have default
2817      initializations.  */
2818   any_default_members = 0;
2819
2820   for (field = &TYPE_FIELDS (t); *field; field = next)
2821     {
2822       tree x = *field;
2823       tree type = TREE_TYPE (x);
2824
2825       next = &TREE_CHAIN (x);
2826
2827       if (TREE_CODE (x) == USING_DECL)
2828         {
2829           /* Prune the access declaration from the list of fields.  */
2830           *field = TREE_CHAIN (x);
2831
2832           /* Save the access declarations for our caller.  */
2833           *access_decls = tree_cons (NULL_TREE, x, *access_decls);
2834
2835           /* Since we've reset *FIELD there's no reason to skip to the
2836              next field.  */
2837           next = field;
2838           continue;
2839         }
2840
2841       if (TREE_CODE (x) == TYPE_DECL
2842           || TREE_CODE (x) == TEMPLATE_DECL)
2843         continue;
2844
2845       /* If we've gotten this far, it's a data member, possibly static,
2846          or an enumerator.  */
2847       DECL_CONTEXT (x) = t;
2848
2849       /* When this goes into scope, it will be a non-local reference.  */
2850       DECL_NONLOCAL (x) = 1;
2851
2852       if (TREE_CODE (t) == UNION_TYPE)
2853         {
2854           /* [class.union]
2855
2856              If a union contains a static data member, or a member of
2857              reference type, the program is ill-formed.  */
2858           if (TREE_CODE (x) == VAR_DECL)
2859             {
2860               error ("%q+D may not be static because it is a member of a union", x);
2861               continue;
2862             }
2863           if (TREE_CODE (type) == REFERENCE_TYPE)
2864             {
2865               error ("%q+D may not have reference type %qT because"
2866                      " it is a member of a union",
2867                      x, type);
2868               continue;
2869             }
2870         }
2871
2872       /* Perform error checking that did not get done in
2873          grokdeclarator.  */
2874       if (TREE_CODE (type) == FUNCTION_TYPE)
2875         {
2876           error ("field %q+D invalidly declared function type", x);
2877           type = build_pointer_type (type);
2878           TREE_TYPE (x) = type;
2879         }
2880       else if (TREE_CODE (type) == METHOD_TYPE)
2881         {
2882           error ("field %q+D invalidly declared method type", x);
2883           type = build_pointer_type (type);
2884           TREE_TYPE (x) = type;
2885         }
2886
2887       if (type == error_mark_node)
2888         continue;
2889
2890       if (TREE_CODE (x) == CONST_DECL || TREE_CODE (x) == VAR_DECL)
2891         continue;
2892
2893       /* Now it can only be a FIELD_DECL.  */
2894
2895       if (TREE_PRIVATE (x) || TREE_PROTECTED (x))
2896         CLASSTYPE_NON_AGGREGATE (t) = 1;
2897
2898       /* If this is of reference type, check if it needs an init.
2899          Also do a little ANSI jig if necessary.  */
2900       if (TREE_CODE (type) == REFERENCE_TYPE)
2901         {
2902           CLASSTYPE_NON_POD_P (t) = 1;
2903           if (DECL_INITIAL (x) == NULL_TREE)
2904             SET_CLASSTYPE_REF_FIELDS_NEED_INIT (t, 1);
2905
2906           /* ARM $12.6.2: [A member initializer list] (or, for an
2907              aggregate, initialization by a brace-enclosed list) is the
2908              only way to initialize nonstatic const and reference
2909              members.  */
2910           TYPE_HAS_COMPLEX_ASSIGN_REF (t) = 1;
2911
2912           if (! TYPE_HAS_CONSTRUCTOR (t) && CLASSTYPE_NON_AGGREGATE (t)
2913               && extra_warnings)
2914             warning (OPT_Wextra, "non-static reference %q+#D in class without a constructor", x);
2915         }
2916
2917       type = strip_array_types (type);
2918
2919       if (TYPE_PACKED (t))
2920         {
2921           if (!pod_type_p (type) && !TYPE_PACKED (type))
2922             {
2923               warning
2924                 (0,
2925                  "ignoring packed attribute because of unpacked non-POD field %q+#D",
2926                  x);
2927               cant_pack = 1;
2928             }
2929           else if (TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
2930             DECL_PACKED (x) = 1;
2931         }
2932
2933       if (DECL_C_BIT_FIELD (x) && integer_zerop (DECL_INITIAL (x)))
2934         /* We don't treat zero-width bitfields as making a class
2935            non-empty.  */
2936         ;
2937       else
2938         {
2939           /* The class is non-empty.  */
2940           CLASSTYPE_EMPTY_P (t) = 0;
2941           /* The class is not even nearly empty.  */
2942           CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
2943           /* If one of the data members contains an empty class,
2944              so does T.  */
2945           if (CLASS_TYPE_P (type)
2946               && CLASSTYPE_CONTAINS_EMPTY_CLASS_P (type))
2947             CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
2948         }
2949
2950       /* This is used by -Weffc++ (see below). Warn only for pointers
2951          to members which might hold dynamic memory. So do not warn
2952          for pointers to functions or pointers to members.  */
2953       if (TYPE_PTR_P (type)
2954           && !TYPE_PTRFN_P (type)
2955           && !TYPE_PTR_TO_MEMBER_P (type))
2956         has_pointers = true;
2957
2958       if (CLASS_TYPE_P (type))
2959         {
2960           if (CLASSTYPE_REF_FIELDS_NEED_INIT (type))
2961             SET_CLASSTYPE_REF_FIELDS_NEED_INIT (t, 1);
2962           if (CLASSTYPE_READONLY_FIELDS_NEED_INIT (type))
2963             SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t, 1);
2964         }
2965
2966       if (DECL_MUTABLE_P (x) || TYPE_HAS_MUTABLE_P (type))
2967         CLASSTYPE_HAS_MUTABLE (t) = 1;
2968
2969       if (! pod_type_p (type))
2970         /* DR 148 now allows pointers to members (which are POD themselves),
2971            to be allowed in POD structs.  */
2972         CLASSTYPE_NON_POD_P (t) = 1;
2973
2974       if (! zero_init_p (type))
2975         CLASSTYPE_NON_ZERO_INIT_P (t) = 1;
2976
2977       /* If any field is const, the structure type is pseudo-const.  */
2978       if (CP_TYPE_CONST_P (type))
2979         {
2980           C_TYPE_FIELDS_READONLY (t) = 1;
2981           if (DECL_INITIAL (x) == NULL_TREE)
2982             SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t, 1);
2983
2984           /* ARM $12.6.2: [A member initializer list] (or, for an
2985              aggregate, initialization by a brace-enclosed list) is the
2986              only way to initialize nonstatic const and reference
2987              members.  */
2988           TYPE_HAS_COMPLEX_ASSIGN_REF (t) = 1;
2989
2990           if (! TYPE_HAS_CONSTRUCTOR (t) && CLASSTYPE_NON_AGGREGATE (t)
2991               && extra_warnings)
2992             warning (OPT_Wextra, "non-static const member %q+#D in class without a constructor", x);
2993         }
2994       /* A field that is pseudo-const makes the structure likewise.  */
2995       else if (CLASS_TYPE_P (type))
2996         {
2997           C_TYPE_FIELDS_READONLY (t) |= C_TYPE_FIELDS_READONLY (type);
2998           SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t,
2999             CLASSTYPE_READONLY_FIELDS_NEED_INIT (t)
3000             | CLASSTYPE_READONLY_FIELDS_NEED_INIT (type));
3001         }
3002
3003       /* Core issue 80: A nonstatic data member is required to have a
3004          different name from the class iff the class has a
3005          user-defined constructor.  */
3006       if (constructor_name_p (DECL_NAME (x), t) && TYPE_HAS_CONSTRUCTOR (t))
3007         pedwarn ("field %q+#D with same name as class", x);
3008
3009       /* We set DECL_C_BIT_FIELD in grokbitfield.
3010          If the type and width are valid, we'll also set DECL_BIT_FIELD.  */
3011       if (DECL_C_BIT_FIELD (x))
3012         check_bitfield_decl (x);
3013       else
3014         check_field_decl (x, t,
3015                           cant_have_const_ctor_p,
3016                           no_const_asn_ref_p,
3017                           &any_default_members);
3018     }
3019
3020   /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3021      it should also define a copy constructor and an assignment operator to
3022      implement the correct copy semantic (deep vs shallow, etc.). As it is
3023      not feasible to check whether the constructors do allocate dynamic memory
3024      and store it within members, we approximate the warning like this:
3025
3026      -- Warn only if there are members which are pointers
3027      -- Warn only if there is a non-trivial constructor (otherwise,
3028         there cannot be memory allocated).
3029      -- Warn only if there is a non-trivial destructor. We assume that the
3030         user at least implemented the cleanup correctly, and a destructor
3031         is needed to free dynamic memory.
3032
3033      This seems enough for practical purposes.  */
3034   if (warn_ecpp
3035       && has_pointers
3036       && TYPE_HAS_CONSTRUCTOR (t)
3037       && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
3038       && !(TYPE_HAS_INIT_REF (t) && TYPE_HAS_ASSIGN_REF (t)))
3039     {
3040       warning (OPT_Weffc__, "%q#T has pointer data members", t);
3041
3042       if (! TYPE_HAS_INIT_REF (t))
3043         {
3044           warning (OPT_Weffc__,
3045                    "  but does not override %<%T(const %T&)%>", t, t);
3046           if (!TYPE_HAS_ASSIGN_REF (t))
3047             warning (OPT_Weffc__, "  or %<operator=(const %T&)%>", t);
3048         }
3049       else if (! TYPE_HAS_ASSIGN_REF (t))
3050         warning (OPT_Weffc__,
3051                  "  but does not override %<operator=(const %T&)%>", t);
3052     }
3053
3054   /* If any of the fields couldn't be packed, unset TYPE_PACKED.  */
3055   if (cant_pack)
3056     TYPE_PACKED (t) = 0;
3057
3058   /* Check anonymous struct/anonymous union fields.  */
3059   finish_struct_anon (t);
3060
3061   /* We've built up the list of access declarations in reverse order.
3062      Fix that now.  */
3063   *access_decls = nreverse (*access_decls);
3064 }
3065
3066 /* If TYPE is an empty class type, records its OFFSET in the table of
3067    OFFSETS.  */
3068
3069 static int
3070 record_subobject_offset (tree type, tree offset, splay_tree offsets)
3071 {
3072   splay_tree_node n;
3073
3074   if (!is_empty_class (type))
3075     return 0;
3076
3077   /* Record the location of this empty object in OFFSETS.  */
3078   n = splay_tree_lookup (offsets, (splay_tree_key) offset);
3079   if (!n)
3080     n = splay_tree_insert (offsets,
3081                            (splay_tree_key) offset,
3082                            (splay_tree_value) NULL_TREE);
3083   n->value = ((splay_tree_value)
3084               tree_cons (NULL_TREE,
3085                          type,
3086                          (tree) n->value));
3087
3088   return 0;
3089 }
3090
3091 /* Returns nonzero if TYPE is an empty class type and there is
3092    already an entry in OFFSETS for the same TYPE as the same OFFSET.  */
3093
3094 static int
3095 check_subobject_offset (tree type, tree offset, splay_tree offsets)
3096 {
3097   splay_tree_node n;
3098   tree t;
3099
3100   if (!is_empty_class (type))
3101     return 0;
3102
3103   /* Record the location of this empty object in OFFSETS.  */
3104   n = splay_tree_lookup (offsets, (splay_tree_key) offset);
3105   if (!n)
3106     return 0;
3107
3108   for (t = (tree) n->value; t; t = TREE_CHAIN (t))
3109     if (same_type_p (TREE_VALUE (t), type))
3110       return 1;
3111
3112   return 0;
3113 }
3114
3115 /* Walk through all the subobjects of TYPE (located at OFFSET).  Call
3116    F for every subobject, passing it the type, offset, and table of
3117    OFFSETS.  If VBASES_P is one, then virtual non-primary bases should
3118    be traversed.
3119
3120    If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3121    than MAX_OFFSET will not be walked.
3122
3123    If F returns a nonzero value, the traversal ceases, and that value
3124    is returned.  Otherwise, returns zero.  */
3125
3126 static int
3127 walk_subobject_offsets (tree type,
3128                         subobject_offset_fn f,
3129                         tree offset,
3130                         splay_tree offsets,
3131                         tree max_offset,
3132                         int vbases_p)
3133 {
3134   int r = 0;
3135   tree type_binfo = NULL_TREE;
3136
3137   /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3138      stop.  */
3139   if (max_offset && INT_CST_LT (max_offset, offset))
3140     return 0;
3141
3142   if (type == error_mark_node)
3143     return 0;
3144
3145   if (!TYPE_P (type))
3146     {
3147       if (abi_version_at_least (2))
3148         type_binfo = type;
3149       type = BINFO_TYPE (type);
3150     }
3151
3152   if (CLASS_TYPE_P (type))
3153     {
3154       tree field;
3155       tree binfo;
3156       int i;
3157
3158       /* Avoid recursing into objects that are not interesting.  */
3159       if (!CLASSTYPE_CONTAINS_EMPTY_CLASS_P (type))
3160         return 0;
3161
3162       /* Record the location of TYPE.  */
3163       r = (*f) (type, offset, offsets);
3164       if (r)
3165         return r;
3166
3167       /* Iterate through the direct base classes of TYPE.  */
3168       if (!type_binfo)
3169         type_binfo = TYPE_BINFO (type);
3170       for (i = 0; BINFO_BASE_ITERATE (type_binfo, i, binfo); i++)
3171         {
3172           tree binfo_offset;
3173
3174           if (abi_version_at_least (2)
3175               && BINFO_VIRTUAL_P (binfo))
3176             continue;
3177
3178           if (!vbases_p
3179               && BINFO_VIRTUAL_P (binfo)
3180               && !BINFO_PRIMARY_P (binfo))
3181             continue;
3182
3183           if (!abi_version_at_least (2))
3184             binfo_offset = size_binop (PLUS_EXPR,
3185                                        offset,
3186                                        BINFO_OFFSET (binfo));
3187           else
3188             {
3189               tree orig_binfo;
3190               /* We cannot rely on BINFO_OFFSET being set for the base
3191                  class yet, but the offsets for direct non-virtual
3192                  bases can be calculated by going back to the TYPE.  */
3193               orig_binfo = BINFO_BASE_BINFO (TYPE_BINFO (type), i);
3194               binfo_offset = size_binop (PLUS_EXPR,
3195                                          offset,
3196                                          BINFO_OFFSET (orig_binfo));
3197             }
3198
3199           r = walk_subobject_offsets (binfo,
3200                                       f,
3201                                       binfo_offset,
3202                                       offsets,
3203                                       max_offset,
3204                                       (abi_version_at_least (2)
3205                                        ? /*vbases_p=*/0 : vbases_p));
3206           if (r)
3207             return r;
3208         }
3209
3210       if (abi_version_at_least (2) && CLASSTYPE_VBASECLASSES (type))
3211         {
3212           unsigned ix;
3213           VEC(tree,gc) *vbases;
3214
3215           /* Iterate through the virtual base classes of TYPE.  In G++
3216              3.2, we included virtual bases in the direct base class
3217              loop above, which results in incorrect results; the
3218              correct offsets for virtual bases are only known when
3219              working with the most derived type.  */
3220           if (vbases_p)
3221             for (vbases = CLASSTYPE_VBASECLASSES (type), ix = 0;
3222                  VEC_iterate (tree, vbases, ix, binfo); ix++)
3223               {
3224                 r = walk_subobject_offsets (binfo,
3225                                             f,
3226                                             size_binop (PLUS_EXPR,
3227                                                         offset,
3228                                                         BINFO_OFFSET (binfo)),
3229                                             offsets,
3230                                             max_offset,
3231                                             /*vbases_p=*/0);
3232                 if (r)
3233                   return r;
3234               }
3235           else
3236             {
3237               /* We still have to walk the primary base, if it is
3238                  virtual.  (If it is non-virtual, then it was walked
3239                  above.)  */
3240               tree vbase = get_primary_binfo (type_binfo);
3241
3242               if (vbase && BINFO_VIRTUAL_P (vbase)
3243                   && BINFO_PRIMARY_P (vbase)
3244                   && BINFO_INHERITANCE_CHAIN (vbase) == type_binfo)
3245                 {
3246                   r = (walk_subobject_offsets
3247                        (vbase, f, offset,
3248                         offsets, max_offset, /*vbases_p=*/0));
3249                   if (r)
3250                     return r;
3251                 }
3252             }
3253         }
3254
3255       /* Iterate through the fields of TYPE.  */
3256       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3257         if (TREE_CODE (field) == FIELD_DECL && !DECL_ARTIFICIAL (field))
3258           {
3259             tree field_offset;
3260
3261             if (abi_version_at_least (2))
3262               field_offset = byte_position (field);
3263             else
3264               /* In G++ 3.2, DECL_FIELD_OFFSET was used.  */
3265               field_offset = DECL_FIELD_OFFSET (field);
3266
3267             r = walk_subobject_offsets (TREE_TYPE (field),
3268                                         f,
3269                                         size_binop (PLUS_EXPR,
3270                                                     offset,
3271                                                     field_offset),
3272                                         offsets,
3273                                         max_offset,
3274                                         /*vbases_p=*/1);
3275             if (r)
3276               return r;
3277           }
3278     }
3279   else if (TREE_CODE (type) == ARRAY_TYPE)
3280     {
3281       tree element_type = strip_array_types (type);
3282       tree domain = TYPE_DOMAIN (type);
3283       tree index;
3284
3285       /* Avoid recursing into objects that are not interesting.  */
3286       if (!CLASS_TYPE_P (element_type)
3287           || !CLASSTYPE_CONTAINS_EMPTY_CLASS_P (element_type))
3288         return 0;
3289
3290       /* Step through each of the elements in the array.  */
3291       for (index = size_zero_node;
3292            /* G++ 3.2 had an off-by-one error here.  */
3293            (abi_version_at_least (2)
3294             ? !INT_CST_LT (TYPE_MAX_VALUE (domain), index)
3295             : INT_CST_LT (index, TYPE_MAX_VALUE (domain)));
3296            index = size_binop (PLUS_EXPR, index, size_one_node))
3297         {
3298           r = walk_subobject_offsets (TREE_TYPE (type),
3299                                       f,
3300                                       offset,
3301                                       offsets,
3302                                       max_offset,
3303                                       /*vbases_p=*/1);
3304           if (r)
3305             return r;
3306           offset = size_binop (PLUS_EXPR, offset,
3307                                TYPE_SIZE_UNIT (TREE_TYPE (type)));
3308           /* If this new OFFSET is bigger than the MAX_OFFSET, then
3309              there's no point in iterating through the remaining
3310              elements of the array.  */
3311           if (max_offset && INT_CST_LT (max_offset, offset))
3312             break;
3313         }
3314     }
3315
3316   return 0;
3317 }
3318
3319 /* Record all of the empty subobjects of TYPE (either a type or a
3320    binfo).  If IS_DATA_MEMBER is true, then a non-static data member
3321    is being placed at OFFSET; otherwise, it is a base class that is
3322    being placed at OFFSET.  */
3323
3324 static void
3325 record_subobject_offsets (tree type,
3326                           tree offset,
3327                           splay_tree offsets,
3328                           bool is_data_member)
3329 {
3330   tree max_offset;
3331   /* If recording subobjects for a non-static data member or a
3332      non-empty base class , we do not need to record offsets beyond
3333      the size of the biggest empty class.  Additional data members
3334      will go at the end of the class.  Additional base classes will go
3335      either at offset zero (if empty, in which case they cannot
3336      overlap with offsets past the size of the biggest empty class) or
3337      at the end of the class.
3338
3339      However, if we are placing an empty base class, then we must record
3340      all offsets, as either the empty class is at offset zero (where
3341      other empty classes might later be placed) or at the end of the
3342      class (where other objects might then be placed, so other empty
3343      subobjects might later overlap).  */
3344   if (is_data_member
3345       || !is_empty_class (BINFO_TYPE (type)))
3346     max_offset = sizeof_biggest_empty_class;
3347   else
3348     max_offset = NULL_TREE;
3349   walk_subobject_offsets (type, record_subobject_offset, offset,
3350                           offsets, max_offset, is_data_member);
3351 }
3352
3353 /* Returns nonzero if any of the empty subobjects of TYPE (located at
3354    OFFSET) conflict with entries in OFFSETS.  If VBASES_P is nonzero,
3355    virtual bases of TYPE are examined.  */
3356
3357 static int
3358 layout_conflict_p (tree type,
3359                    tree offset,
3360                    splay_tree offsets,
3361                    int vbases_p)
3362 {
3363   splay_tree_node max_node;
3364
3365   /* Get the node in OFFSETS that indicates the maximum offset where
3366      an empty subobject is located.  */
3367   max_node = splay_tree_max (offsets);
3368   /* If there aren't any empty subobjects, then there's no point in
3369      performing this check.  */
3370   if (!max_node)
3371     return 0;
3372
3373   return walk_subobject_offsets (type, check_subobject_offset, offset,
3374                                  offsets, (tree) (max_node->key),
3375                                  vbases_p);
3376 }
3377
3378 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
3379    non-static data member of the type indicated by RLI.  BINFO is the
3380    binfo corresponding to the base subobject, OFFSETS maps offsets to
3381    types already located at those offsets.  This function determines
3382    the position of the DECL.  */
3383
3384 static void
3385 layout_nonempty_base_or_field (record_layout_info rli,
3386                                tree decl,
3387                                tree binfo,
3388                                splay_tree offsets)
3389 {
3390   tree offset = NULL_TREE;
3391   bool field_p;
3392   tree type;
3393
3394   if (binfo)
3395     {
3396       /* For the purposes of determining layout conflicts, we want to
3397          use the class type of BINFO; TREE_TYPE (DECL) will be the
3398          CLASSTYPE_AS_BASE version, which does not contain entries for
3399          zero-sized bases.  */
3400       type = TREE_TYPE (binfo);
3401       field_p = false;
3402     }
3403   else
3404     {
3405       type = TREE_TYPE (decl);
3406       field_p = true;
3407     }
3408
3409   /* Try to place the field.  It may take more than one try if we have
3410      a hard time placing the field without putting two objects of the
3411      same type at the same address.  */
3412   while (1)
3413     {
3414       struct record_layout_info_s old_rli = *rli;
3415
3416       /* Place this field.  */
3417       place_field (rli, decl);
3418       offset = byte_position (decl);
3419
3420       /* We have to check to see whether or not there is already
3421          something of the same type at the offset we're about to use.
3422          For example, consider:
3423
3424            struct S {};
3425            struct T : public S { int i; };
3426            struct U : public S, public T {};
3427
3428          Here, we put S at offset zero in U.  Then, we can't put T at
3429          offset zero -- its S component would be at the same address
3430          as the S we already allocated.  So, we have to skip ahead.
3431          Since all data members, including those whose type is an
3432          empty class, have nonzero size, any overlap can happen only
3433          with a direct or indirect base-class -- it can't happen with
3434          a data member.  */
3435       /* In a union, overlap is permitted; all members are placed at
3436          offset zero.  */
3437       if (TREE_CODE (rli->t) == UNION_TYPE)
3438         break;
3439       /* G++ 3.2 did not check for overlaps when placing a non-empty
3440          virtual base.  */
3441       if (!abi_version_at_least (2) && binfo && BINFO_VIRTUAL_P (binfo))
3442         break;
3443       if (layout_conflict_p (field_p ? type : binfo, offset,
3444                              offsets, field_p))
3445         {
3446           /* Strip off the size allocated to this field.  That puts us
3447              at the first place we could have put the field with
3448              proper alignment.  */
3449           *rli = old_rli;
3450
3451           /* Bump up by the alignment required for the type.  */
3452           rli->bitpos
3453             = size_binop (PLUS_EXPR, rli->bitpos,
3454                           bitsize_int (binfo
3455                                        ? CLASSTYPE_ALIGN (type)
3456                                        : TYPE_ALIGN (type)));
3457           normalize_rli (rli);
3458         }
3459       else
3460         /* There was no conflict.  We're done laying out this field.  */
3461         break;
3462     }
3463
3464   /* Now that we know where it will be placed, update its
3465      BINFO_OFFSET.  */
3466   if (binfo && CLASS_TYPE_P (BINFO_TYPE (binfo)))
3467     /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
3468        this point because their BINFO_OFFSET is copied from another
3469        hierarchy.  Therefore, we may not need to add the entire
3470        OFFSET.  */
3471     propagate_binfo_offsets (binfo,
3472                              size_diffop (convert (ssizetype, offset),
3473                                           convert (ssizetype,
3474                                                    BINFO_OFFSET (binfo))));
3475 }
3476
3477 /* Returns true if TYPE is empty and OFFSET is nonzero.  */
3478
3479 static int
3480 empty_base_at_nonzero_offset_p (tree type,
3481                                 tree offset,
3482                                 splay_tree offsets ATTRIBUTE_UNUSED)
3483 {
3484   return is_empty_class (type) && !integer_zerop (offset);
3485 }
3486
3487 /* Layout the empty base BINFO.  EOC indicates the byte currently just
3488    past the end of the class, and should be correctly aligned for a
3489    class of the type indicated by BINFO; OFFSETS gives the offsets of
3490    the empty bases allocated so far. T is the most derived
3491    type.  Return nonzero iff we added it at the end.  */
3492
3493 static bool
3494 layout_empty_base (tree binfo, tree eoc, splay_tree offsets)
3495 {
3496   tree alignment;
3497   tree basetype = BINFO_TYPE (binfo);
3498   bool atend = false;
3499
3500   /* This routine should only be used for empty classes.  */
3501   gcc_assert (is_empty_class (basetype));
3502   alignment = ssize_int (CLASSTYPE_ALIGN_UNIT (basetype));
3503
3504   if (!integer_zerop (BINFO_OFFSET (binfo)))
3505     {
3506       if (abi_version_at_least (2))
3507         propagate_binfo_offsets
3508           (binfo, size_diffop (size_zero_node, BINFO_OFFSET (binfo)));
3509       else
3510         warning (OPT_Wabi,
3511                  "offset of empty base %qT may not be ABI-compliant and may"
3512                  "change in a future version of GCC",
3513                  BINFO_TYPE (binfo));
3514     }
3515
3516   /* This is an empty base class.  We first try to put it at offset
3517      zero.  */
3518   if (layout_conflict_p (binfo,
3519                          BINFO_OFFSET (binfo),
3520                          offsets,
3521                          /*vbases_p=*/0))
3522     {
3523       /* That didn't work.  Now, we move forward from the next
3524          available spot in the class.  */
3525       atend = true;
3526       propagate_binfo_offsets (binfo, convert (ssizetype, eoc));
3527       while (1)
3528         {
3529           if (!layout_conflict_p (binfo,
3530                                   BINFO_OFFSET (binfo),
3531                                   offsets,
3532                                   /*vbases_p=*/0))
3533             /* We finally found a spot where there's no overlap.  */
3534             break;
3535
3536           /* There's overlap here, too.  Bump along to the next spot.  */
3537           propagate_binfo_offsets (binfo, alignment);
3538         }
3539     }
3540   return atend;
3541 }
3542
3543 /* Layout the base given by BINFO in the class indicated by RLI.
3544    *BASE_ALIGN is a running maximum of the alignments of
3545    any base class.  OFFSETS gives the location of empty base
3546    subobjects.  T is the most derived type.  Return nonzero if the new
3547    object cannot be nearly-empty.  A new FIELD_DECL is inserted at
3548    *NEXT_FIELD, unless BINFO is for an empty base class.
3549
3550    Returns the location at which the next field should be inserted.  */
3551
3552 static tree *
3553 build_base_field (record_layout_info rli, tree binfo,
3554                   splay_tree offsets, tree *next_field)
3555 {
3556   tree t = rli->t;
3557   tree basetype = BINFO_TYPE (binfo);
3558
3559   if (!COMPLETE_TYPE_P (basetype))
3560     /* This error is now reported in xref_tag, thus giving better
3561        location information.  */
3562     return next_field;
3563
3564   /* Place the base class.  */
3565   if (!is_empty_class (basetype))
3566     {
3567       tree decl;
3568
3569       /* The containing class is non-empty because it has a non-empty
3570          base class.  */
3571       CLASSTYPE_EMPTY_P (t) = 0;
3572
3573       /* Create the FIELD_DECL.  */
3574       decl = build_decl (FIELD_DECL, NULL_TREE, CLASSTYPE_AS_BASE (basetype));
3575       DECL_ARTIFICIAL (decl) = 1;
3576       DECL_IGNORED_P (decl) = 1;
3577       DECL_FIELD_CONTEXT (decl) = t;
3578       DECL_SIZE (decl) = CLASSTYPE_SIZE (basetype);
3579       DECL_SIZE_UNIT (decl) = CLASSTYPE_SIZE_UNIT (basetype);
3580       DECL_ALIGN (decl) = CLASSTYPE_ALIGN (basetype);
3581       DECL_USER_ALIGN (decl) = CLASSTYPE_USER_ALIGN (basetype);
3582       DECL_MODE (decl) = TYPE_MODE (basetype);
3583       DECL_FIELD_IS_BASE (decl) = 1;
3584
3585       /* Try to place the field.  It may take more than one try if we
3586          have a hard time placing the field without putting two
3587          objects of the same type at the same address.  */
3588       layout_nonempty_base_or_field (rli, decl, binfo, offsets);
3589       /* Add the new FIELD_DECL to the list of fields for T.  */
3590       TREE_CHAIN (decl) = *next_field;
3591       *next_field = decl;
3592       next_field = &TREE_CHAIN (decl);
3593     }
3594   else
3595     {
3596       tree eoc;
3597       bool atend;
3598
3599       /* On some platforms (ARM), even empty classes will not be
3600          byte-aligned.  */
3601       eoc = round_up (rli_size_unit_so_far (rli),
3602                       CLASSTYPE_ALIGN_UNIT (basetype));
3603       atend = layout_empty_base (binfo, eoc, offsets);
3604       /* A nearly-empty class "has no proper base class that is empty,
3605          not morally virtual, and at an offset other than zero."  */
3606       if (!BINFO_VIRTUAL_P (binfo) && CLASSTYPE_NEARLY_EMPTY_P (t))
3607         {
3608           if (atend)
3609             CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
3610           /* The check above (used in G++ 3.2) is insufficient because
3611              an empty class placed at offset zero might itself have an
3612              empty base at a nonzero offset.  */
3613           else if (walk_subobject_offsets (basetype,
3614                                            empty_base_at_nonzero_offset_p,
3615                                            size_zero_node,
3616                                            /*offsets=*/NULL,
3617                                            /*max_offset=*/NULL_TREE,
3618                                            /*vbases_p=*/true))
3619             {
3620               if (abi_version_at_least (2))
3621                 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
3622               else
3623                 warning (OPT_Wabi,
3624                          "class %qT will be considered nearly empty in a "
3625                          "future version of GCC", t);
3626             }
3627         }
3628
3629       /* We do not create a FIELD_DECL for empty base classes because
3630          it might overlap some other field.  We want to be able to
3631          create CONSTRUCTORs for the class by iterating over the
3632          FIELD_DECLs, and the back end does not handle overlapping
3633          FIELD_DECLs.  */
3634
3635       /* An empty virtual base causes a class to be non-empty
3636          -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
3637          here because that was already done when the virtual table
3638          pointer was created.  */
3639     }
3640
3641   /* Record the offsets of BINFO and its base subobjects.  */
3642   record_subobject_offsets (binfo,
3643                             BINFO_OFFSET (binfo),
3644                             offsets,
3645                             /*is_data_member=*/false);
3646
3647   return next_field;
3648 }
3649
3650 /* Layout all of the non-virtual base classes.  Record empty
3651    subobjects in OFFSETS.  T is the most derived type.  Return nonzero
3652    if the type cannot be nearly empty.  The fields created
3653    corresponding to the base classes will be inserted at
3654    *NEXT_FIELD.  */
3655
3656 static void
3657 build_base_fields (record_layout_info rli,
3658                    splay_tree offsets, tree *next_field)
3659 {
3660   /* Chain to hold all the new FIELD_DECLs which stand in for base class
3661      subobjects.  */
3662   tree t = rli->t;
3663   int n_baseclasses = BINFO_N_BASE_BINFOS (TYPE_BINFO (t));
3664   int i;
3665
3666   /* The primary base class is always allocated first.  */
3667   if (CLASSTYPE_HAS_PRIMARY_BASE_P (t))
3668     next_field = build_base_field (rli, CLASSTYPE_PRIMARY_BINFO (t),
3669                                    offsets, next_field);
3670
3671   /* Now allocate the rest of the bases.  */
3672   for (i = 0; i < n_baseclasses; ++i)
3673     {
3674       tree base_binfo;
3675
3676       base_binfo = BINFO_BASE_BINFO (TYPE_BINFO (t), i);
3677
3678       /* The primary base was already allocated above, so we don't
3679          need to allocate it again here.  */
3680       if (base_binfo == CLASSTYPE_PRIMARY_BINFO (t))
3681         continue;
3682
3683       /* Virtual bases are added at the end (a primary virtual base
3684          will have already been added).  */
3685       if (BINFO_VIRTUAL_P (base_binfo))
3686         continue;
3687
3688       next_field = build_base_field (rli, base_binfo,
3689                                      offsets, next_field);
3690     }
3691 }
3692
3693 /* Go through the TYPE_METHODS of T issuing any appropriate
3694    diagnostics, figuring out which methods override which other
3695    methods, and so forth.  */
3696
3697 static void
3698 check_methods (tree t)
3699 {
3700   tree x;
3701
3702   for (x = TYPE_METHODS (t); x; x = TREE_CHAIN (x))
3703     {
3704       check_for_override (x, t);
3705       if (DECL_PURE_VIRTUAL_P (x) && ! DECL_VINDEX (x))
3706         error ("initializer specified for non-virtual method %q+D", x);
3707       /* The name of the field is the original field name
3708          Save this in auxiliary field for later overloading.  */
3709       if (DECL_VINDEX (x))
3710         {
3711           TYPE_POLYMORPHIC_P (t) = 1;
3712           if (DECL_PURE_VIRTUAL_P (x))
3713             VEC_safe_push (tree, gc, CLASSTYPE_PURE_VIRTUALS (t), x);
3714         }
3715       /* All user-declared destructors are non-trivial.  */
3716       if (DECL_DESTRUCTOR_P (x))
3717         TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t) = 1;
3718     }
3719 }
3720
3721 /* FN is a constructor or destructor.  Clone the declaration to create
3722    a specialized in-charge or not-in-charge version, as indicated by
3723    NAME.  */
3724
3725 static tree
3726 build_clone (tree fn, tree name)
3727 {
3728   tree parms;
3729   tree clone;
3730
3731   /* Copy the function.  */
3732   clone = copy_decl (fn);
3733   /* Remember where this function came from.  */
3734   DECL_CLONED_FUNCTION (clone) = fn;
3735   DECL_ABSTRACT_ORIGIN (clone) = fn;
3736   /* Reset the function name.  */
3737   DECL_NAME (clone) = name;
3738   SET_DECL_ASSEMBLER_NAME (clone, NULL_TREE);
3739   /* There's no pending inline data for this function.  */
3740   DECL_PENDING_INLINE_INFO (clone) = NULL;
3741   DECL_PENDING_INLINE_P (clone) = 0;
3742   /* And it hasn't yet been deferred.  */
3743   DECL_DEFERRED_FN (clone) = 0;
3744
3745   /* The base-class destructor is not virtual.  */
3746   if (name == base_dtor_identifier)
3747     {
3748       DECL_VIRTUAL_P (clone) = 0;
3749       if (TREE_CODE (clone) != TEMPLATE_DECL)
3750         DECL_VINDEX (clone) = NULL_TREE;
3751     }
3752
3753   /* If there was an in-charge parameter, drop it from the function
3754      type.  */
3755   if (DECL_HAS_IN_CHARGE_PARM_P (clone))
3756     {
3757       tree basetype;
3758       tree parmtypes;
3759       tree exceptions;
3760
3761       exceptions = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (clone));
3762       basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (clone));
3763       parmtypes = TYPE_ARG_TYPES (TREE_TYPE (clone));
3764       /* Skip the `this' parameter.  */
3765       parmtypes = TREE_CHAIN (parmtypes);
3766       /* Skip the in-charge parameter.  */
3767       parmtypes = TREE_CHAIN (parmtypes);
3768       /* And the VTT parm, in a complete [cd]tor.  */
3769       if (DECL_HAS_VTT_PARM_P (fn)
3770           && ! DECL_NEEDS_VTT_PARM_P (clone))
3771         parmtypes = TREE_CHAIN (parmtypes);
3772        /* If this is subobject constructor or destructor, add the vtt
3773          parameter.  */
3774       TREE_TYPE (clone)
3775         = build_method_type_directly (basetype,
3776                                       TREE_TYPE (TREE_TYPE (clone)),
3777                                       parmtypes);
3778       if (exceptions)
3779         TREE_TYPE (clone) = build_exception_variant (TREE_TYPE (clone),
3780                                                      exceptions);
3781       TREE_TYPE (clone)
3782         = cp_build_type_attribute_variant (TREE_TYPE (clone),
3783                                            TYPE_ATTRIBUTES (TREE_TYPE (fn)));
3784     }
3785
3786   /* Copy the function parameters.  But, DECL_ARGUMENTS on a TEMPLATE_DECL
3787      aren't function parameters; those are the template parameters.  */
3788   if (TREE_CODE (clone) != TEMPLATE_DECL)
3789     {
3790       DECL_ARGUMENTS (clone) = copy_list (DECL_ARGUMENTS (clone));
3791       /* Remove the in-charge parameter.  */
3792       if (DECL_HAS_IN_CHARGE_PARM_P (clone))
3793         {
3794           TREE_CHAIN (DECL_ARGUMENTS (clone))
3795             = TREE_CHAIN (TREE_CHAIN (DECL_ARGUMENTS (clone)));
3796           DECL_HAS_IN_CHARGE_PARM_P (clone) = 0;
3797         }
3798       /* And the VTT parm, in a complete [cd]tor.  */
3799       if (DECL_HAS_VTT_PARM_P (fn))
3800         {
3801           if (DECL_NEEDS_VTT_PARM_P (clone))
3802             DECL_HAS_VTT_PARM_P (clone) = 1;
3803           else
3804             {
3805               TREE_CHAIN (DECL_ARGUMENTS (clone))
3806                 = TREE_CHAIN (TREE_CHAIN (DECL_ARGUMENTS (clone)));
3807               DECL_HAS_VTT_PARM_P (clone) = 0;
3808             }
3809         }
3810
3811       for (parms = DECL_ARGUMENTS (clone); parms; parms = TREE_CHAIN (parms))
3812         {
3813           DECL_CONTEXT (parms) = clone;
3814           cxx_dup_lang_specific_decl (parms);
3815         }
3816     }
3817
3818   /* Create the RTL for this function.  */
3819   SET_DECL_RTL (clone, NULL_RTX);
3820   rest_of_decl_compilation (clone, /*top_level=*/1, at_eof);
3821
3822   /* Make it easy to find the CLONE given the FN.  */
3823   TREE_CHAIN (clone) = TREE_CHAIN (fn);
3824   TREE_CHAIN (fn) = clone;
3825
3826   /* If this is a template, handle the DECL_TEMPLATE_RESULT as well.  */
3827   if (TREE_CODE (clone) == TEMPLATE_DECL)
3828     {
3829       tree result;
3830
3831       DECL_TEMPLATE_RESULT (clone)
3832         = build_clone (DECL_TEMPLATE_RESULT (clone), name);
3833       result = DECL_TEMPLATE_RESULT (clone);
3834       DECL_TEMPLATE_INFO (result) = copy_node (DECL_TEMPLATE_INFO (result));
3835       DECL_TI_TEMPLATE (result) = clone;
3836     }
3837   else if (pch_file)
3838     note_decl_for_pch (clone);
3839
3840   return clone;
3841 }
3842
3843 /* Produce declarations for all appropriate clones of FN.  If
3844    UPDATE_METHOD_VEC_P is nonzero, the clones are added to the
3845    CLASTYPE_METHOD_VEC as well.  */
3846
3847 void
3848 clone_function_decl (tree fn, int update_method_vec_p)
3849 {
3850   tree clone;
3851
3852   /* Avoid inappropriate cloning.  */
3853   if (TREE_CHAIN (fn)
3854       && DECL_CLONED_FUNCTION (TREE_CHAIN (fn)))
3855     return;
3856
3857   if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn))
3858     {
3859       /* For each constructor, we need two variants: an in-charge version
3860          and a not-in-charge version.  */
3861       clone = build_clone (fn, complete_ctor_identifier);
3862       if (update_method_vec_p)
3863         add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3864       clone = build_clone (fn, base_ctor_identifier);
3865       if (update_method_vec_p)
3866         add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3867     }
3868   else
3869     {
3870       gcc_assert (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn));
3871
3872       /* For each destructor, we need three variants: an in-charge
3873          version, a not-in-charge version, and an in-charge deleting
3874          version.  We clone the deleting version first because that
3875          means it will go second on the TYPE_METHODS list -- and that
3876          corresponds to the correct layout order in the virtual
3877          function table.
3878
3879          For a non-virtual destructor, we do not build a deleting
3880          destructor.  */
3881       if (DECL_VIRTUAL_P (fn))
3882         {
3883           clone = build_clone (fn, deleting_dtor_identifier);
3884           if (update_method_vec_p)
3885             add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3886         }
3887       clone = build_clone (fn, complete_dtor_identifier);
3888       if (update_method_vec_p)
3889         add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3890       clone = build_clone (fn, base_dtor_identifier);
3891       if (update_method_vec_p)
3892         add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3893     }
3894
3895   /* Note that this is an abstract function that is never emitted.  */
3896   DECL_ABSTRACT (fn) = 1;
3897 }
3898
3899 /* DECL is an in charge constructor, which is being defined. This will
3900    have had an in class declaration, from whence clones were
3901    declared. An out-of-class definition can specify additional default
3902    arguments. As it is the clones that are involved in overload
3903    resolution, we must propagate the information from the DECL to its
3904    clones.  */
3905
3906 void
3907 adjust_clone_args (tree decl)
3908 {
3909   tree clone;
3910
3911   for (clone = TREE_CHAIN (decl); clone && DECL_CLONED_FUNCTION (clone);
3912        clone = TREE_CHAIN (clone))
3913     {
3914       tree orig_clone_parms = TYPE_ARG_TYPES (TREE_TYPE (clone));
3915       tree orig_decl_parms = TYPE_ARG_TYPES (TREE_TYPE (decl));
3916       tree decl_parms, clone_parms;
3917
3918       clone_parms = orig_clone_parms;
3919
3920       /* Skip the 'this' parameter.  */
3921       orig_clone_parms = TREE_CHAIN (orig_clone_parms);
3922       orig_decl_parms = TREE_CHAIN (orig_decl_parms);
3923
3924       if (DECL_HAS_IN_CHARGE_PARM_P (decl))
3925         orig_decl_parms = TREE_CHAIN (orig_decl_parms);
3926       if (DECL_HAS_VTT_PARM_P (decl))
3927         orig_decl_parms = TREE_CHAIN (orig_decl_parms);
3928
3929       clone_parms = orig_clone_parms;
3930       if (DECL_HAS_VTT_PARM_P (clone))
3931         clone_parms = TREE_CHAIN (clone_parms);
3932
3933       for (decl_parms = orig_decl_parms; decl_parms;
3934            decl_parms = TREE_CHAIN (decl_parms),
3935              clone_parms = TREE_CHAIN (clone_parms))
3936         {
3937           gcc_assert (same_type_p (TREE_TYPE (decl_parms),
3938                                    TREE_TYPE (clone_parms)));
3939
3940           if (TREE_PURPOSE (decl_parms) && !TREE_PURPOSE (clone_parms))
3941             {
3942               /* A default parameter has been added. Adjust the
3943                  clone's parameters.  */
3944               tree exceptions = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (clone));
3945               tree basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (clone));
3946               tree type;
3947
3948               clone_parms = orig_decl_parms;
3949
3950               if (DECL_HAS_VTT_PARM_P (clone))
3951                 {
3952                   clone_parms = tree_cons (TREE_PURPOSE (orig_clone_parms),
3953                                            TREE_VALUE (orig_clone_parms),
3954                                            clone_parms);
3955                   TREE_TYPE (clone_parms) = TREE_TYPE (orig_clone_parms);
3956                 }
3957               type = build_method_type_directly (basetype,
3958                                                  TREE_TYPE (TREE_TYPE (clone)),
3959                                                  clone_parms);
3960               if (exceptions)
3961                 type = build_exception_variant (type, exceptions);
3962               TREE_TYPE (clone) = type;
3963
3964               clone_parms = NULL_TREE;
3965               break;
3966             }
3967         }
3968       gcc_assert (!clone_parms);
3969     }
3970 }
3971
3972 /* For each of the constructors and destructors in T, create an
3973    in-charge and not-in-charge variant.  */
3974
3975 static void
3976 clone_constructors_and_destructors (tree t)
3977 {
3978   tree fns;
3979
3980   /* If for some reason we don't have a CLASSTYPE_METHOD_VEC, we bail
3981      out now.  */
3982   if (!CLASSTYPE_METHOD_VEC (t))
3983     return;
3984
3985   for (fns = CLASSTYPE_CONSTRUCTORS (t); fns; fns = OVL_NEXT (fns))
3986     clone_function_decl (OVL_CURRENT (fns), /*update_method_vec_p=*/1);
3987   for (fns = CLASSTYPE_DESTRUCTORS (t); fns; fns = OVL_NEXT (fns))
3988     clone_function_decl (OVL_CURRENT (fns), /*update_method_vec_p=*/1);
3989 }
3990
3991 /* Remove all zero-width bit-fields from T.  */
3992
3993 static void
3994 remove_zero_width_bit_fields (tree t)
3995 {
3996   tree *fieldsp;
3997
3998   fieldsp = &TYPE_FIELDS (t);
3999   while (*fieldsp)
4000     {
4001       if (TREE_CODE (*fieldsp) == FIELD_DECL
4002           && DECL_C_BIT_FIELD (*fieldsp)
4003           && DECL_INITIAL (*fieldsp))
4004         *fieldsp = TREE_CHAIN (*fieldsp);
4005       else
4006         fieldsp = &TREE_CHAIN (*fieldsp);
4007     }
4008 }
4009
4010 /* Returns TRUE iff we need a cookie when dynamically allocating an
4011    array whose elements have the indicated class TYPE.  */
4012
4013 static bool
4014 type_requires_array_cookie (tree type)
4015 {
4016   tree fns;
4017   bool has_two_argument_delete_p = false;
4018
4019   gcc_assert (CLASS_TYPE_P (type));
4020
4021   /* If there's a non-trivial destructor, we need a cookie.  In order
4022      to iterate through the array calling the destructor for each
4023      element, we'll have to know how many elements there are.  */
4024   if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
4025     return true;
4026
4027   /* If the usual deallocation function is a two-argument whose second
4028      argument is of type `size_t', then we have to pass the size of
4029      the array to the deallocation function, so we will need to store
4030      a cookie.  */
4031   fns = lookup_fnfields (TYPE_BINFO (type),
4032                          ansi_opname (VEC_DELETE_EXPR),
4033                          /*protect=*/0);
4034   /* If there are no `operator []' members, or the lookup is
4035      ambiguous, then we don't need a cookie.  */
4036   if (!fns || fns == error_mark_node)
4037     return false;
4038   /* Loop through all of the functions.  */
4039   for (fns = BASELINK_FUNCTIONS (fns); fns; fns = OVL_NEXT (fns))
4040     {
4041       tree fn;
4042       tree second_parm;
4043
4044       /* Select the current function.  */
4045       fn = OVL_CURRENT (fns);
4046       /* See if this function is a one-argument delete function.  If
4047          it is, then it will be the usual deallocation function.  */
4048       second_parm = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fn)));
4049       if (second_parm == void_list_node)
4050         return false;
4051       /* Otherwise, if we have a two-argument function and the second
4052          argument is `size_t', it will be the usual deallocation
4053          function -- unless there is one-argument function, too.  */
4054       if (TREE_CHAIN (second_parm) == void_list_node
4055           && same_type_p (TREE_VALUE (second_parm), size_type_node))
4056         has_two_argument_delete_p = true;
4057     }
4058
4059   return has_two_argument_delete_p;
4060 }
4061
4062 /* Check the validity of the bases and members declared in T.  Add any
4063    implicitly-generated functions (like copy-constructors and
4064    assignment operators).  Compute various flag bits (like
4065    CLASSTYPE_NON_POD_T) for T.  This routine works purely at the C++
4066    level: i.e., independently of the ABI in use.  */
4067
4068 static void
4069 check_bases_and_members (tree t)
4070 {
4071   /* Nonzero if the implicitly generated copy constructor should take
4072      a non-const reference argument.  */
4073   int cant_have_const_ctor;
4074   /* Nonzero if the implicitly generated assignment operator
4075      should take a non-const reference argument.  */
4076   int no_const_asn_ref;
4077   tree access_decls;
4078
4079   /* By default, we use const reference arguments and generate default
4080      constructors.  */
4081   cant_have_const_ctor = 0;
4082   no_const_asn_ref = 0;
4083
4084   /* Check all the base-classes.  */
4085   check_bases (t, &cant_have_const_ctor,
4086                &no_const_asn_ref);
4087
4088   /* Check all the method declarations.  */
4089   check_methods (t);
4090
4091   /* Check all the data member declarations.  We cannot call
4092      check_field_decls until we have called check_bases check_methods,
4093      as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
4094      being set appropriately.  */
4095   check_field_decls (t, &access_decls,
4096                      &cant_have_const_ctor,
4097                      &no_const_asn_ref);
4098
4099   /* A nearly-empty class has to be vptr-containing; a nearly empty
4100      class contains just a vptr.  */
4101   if (!TYPE_CONTAINS_VPTR_P (t))
4102     CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
4103
4104   /* Do some bookkeeping that will guide the generation of implicitly
4105      declared member functions.  */
4106   TYPE_HAS_COMPLEX_INIT_REF (t)
4107     |= (TYPE_HAS_INIT_REF (t) || TYPE_CONTAINS_VPTR_P (t));
4108   TYPE_NEEDS_CONSTRUCTING (t)
4109     |= (TYPE_HAS_CONSTRUCTOR (t) || TYPE_CONTAINS_VPTR_P (t));
4110   CLASSTYPE_NON_AGGREGATE (t)
4111     |= (TYPE_HAS_CONSTRUCTOR (t) || TYPE_POLYMORPHIC_P (t));
4112   CLASSTYPE_NON_POD_P (t)
4113     |= (CLASSTYPE_NON_AGGREGATE (t)
4114         || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
4115         || TYPE_HAS_ASSIGN_REF (t));
4116   TYPE_HAS_COMPLEX_ASSIGN_REF (t)
4117     |= TYPE_HAS_ASSIGN_REF (t) || TYPE_CONTAINS_VPTR_P (t);
4118   TYPE_HAS_COMPLEX_DFLT (t)
4119     |= (TYPE_HAS_DEFAULT_CONSTRUCTOR (t) || TYPE_CONTAINS_VPTR_P (t));
4120
4121   /* Synthesize any needed methods.  */
4122   add_implicitly_declared_members (t,
4123                                    cant_have_const_ctor,
4124                                    no_const_asn_ref);
4125
4126   /* Create the in-charge and not-in-charge variants of constructors
4127      and destructors.  */
4128   clone_constructors_and_destructors (t);
4129
4130   /* Process the using-declarations.  */
4131   for (; access_decls; access_decls = TREE_CHAIN (access_decls))
4132     handle_using_decl (TREE_VALUE (access_decls), t);
4133
4134   /* Build and sort the CLASSTYPE_METHOD_VEC.  */
4135   finish_struct_methods (t);
4136
4137   /* Figure out whether or not we will need a cookie when dynamically
4138      allocating an array of this type.  */
4139   TYPE_LANG_SPECIFIC (t)->u.c.vec_new_uses_cookie
4140     = type_requires_array_cookie (t);
4141 }
4142
4143 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
4144    accordingly.  If a new vfield was created (because T doesn't have a
4145    primary base class), then the newly created field is returned.  It
4146    is not added to the TYPE_FIELDS list; it is the caller's
4147    responsibility to do that.  Accumulate declared virtual functions
4148    on VIRTUALS_P.  */
4149
4150 static tree
4151 create_vtable_ptr (tree t, tree* virtuals_p)
4152 {
4153   tree fn;
4154
4155   /* Collect the virtual functions declared in T.  */
4156   for (fn = TYPE_METHODS (t); fn; fn = TREE_CHAIN (fn))
4157     if (DECL_VINDEX (fn) && !DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn)
4158         && TREE_CODE (DECL_VINDEX (fn)) != INTEGER_CST)
4159       {
4160         tree new_virtual = make_node (TREE_LIST);
4161
4162         BV_FN (new_virtual) = fn;
4163         BV_DELTA (new_virtual) = integer_zero_node;
4164         BV_VCALL_INDEX (new_virtual) = NULL_TREE;
4165
4166         TREE_CHAIN (new_virtual) = *virtuals_p;
4167         *virtuals_p = new_virtual;
4168       }
4169
4170   /* If we couldn't find an appropriate base class, create a new field
4171      here.  Even if there weren't any new virtual functions, we might need a
4172      new virtual function table if we're supposed to include vptrs in
4173      all classes that need them.  */
4174   if (!TYPE_VFIELD (t) && (*virtuals_p || TYPE_CONTAINS_VPTR_P (t)))
4175     {
4176       /* We build this decl with vtbl_ptr_type_node, which is a
4177          `vtable_entry_type*'.  It might seem more precise to use
4178          `vtable_entry_type (*)[N]' where N is the number of virtual
4179          functions.  However, that would require the vtable pointer in
4180          base classes to have a different type than the vtable pointer
4181          in derived classes.  We could make that happen, but that
4182          still wouldn't solve all the problems.  In particular, the
4183          type-based alias analysis code would decide that assignments
4184          to the base class vtable pointer can't alias assignments to
4185          the derived class vtable pointer, since they have different
4186          types.  Thus, in a derived class destructor, where the base
4187          class constructor was inlined, we could generate bad code for
4188          setting up the vtable pointer.
4189
4190          Therefore, we use one type for all vtable pointers.  We still
4191          use a type-correct type; it's just doesn't indicate the array
4192          bounds.  That's better than using `void*' or some such; it's
4193          cleaner, and it let's the alias analysis code know that these
4194          stores cannot alias stores to void*!  */
4195       tree field;
4196
4197       field = build_decl (FIELD_DECL, get_vfield_name (t), vtbl_ptr_type_node);
4198       DECL_VIRTUAL_P (field) = 1;
4199       DECL_ARTIFICIAL (field) = 1;
4200       DECL_FIELD_CONTEXT (field) = t;
4201       DECL_FCONTEXT (field) = t;
4202
4203       TYPE_VFIELD (t) = field;
4204
4205       /* This class is non-empty.  */
4206       CLASSTYPE_EMPTY_P (t) = 0;
4207
4208       return field;
4209     }
4210
4211   return NULL_TREE;
4212 }
4213
4214 /* Fixup the inline function given by INFO now that the class is
4215    complete.  */
4216
4217 static void
4218 fixup_pending_inline (tree fn)
4219 {
4220   if (DECL_PENDING_INLINE_INFO (fn))
4221     {
4222       tree args = DECL_ARGUMENTS (fn);
4223       while (args)
4224         {
4225           DECL_CONTEXT (args) = fn;
4226           args = TREE_CHAIN (args);
4227         }
4228     }
4229 }
4230
4231 /* Fixup the inline methods and friends in TYPE now that TYPE is
4232    complete.  */
4233
4234 static void
4235 fixup_inline_methods (tree type)
4236 {
4237   tree method = TYPE_METHODS (type);
4238   VEC(tree,gc) *friends;
4239   unsigned ix;
4240
4241   if (method && TREE_CODE (method) == TREE_VEC)
4242     {
4243       if (TREE_VEC_ELT (method, 1))
4244         method = TREE_VEC_ELT (method, 1);
4245       else if (TREE_VEC_ELT (method, 0))
4246         method = TREE_VEC_ELT (method, 0);
4247       else
4248         method = TREE_VEC_ELT (method, 2);
4249     }
4250
4251   /* Do inline member functions.  */
4252   for (; method; method = TREE_CHAIN (method))
4253     fixup_pending_inline (method);
4254
4255   /* Do friends.  */
4256   for (friends = CLASSTYPE_INLINE_FRIENDS (type), ix = 0;
4257        VEC_iterate (tree, friends, ix, method); ix++)
4258     fixup_pending_inline (method);
4259   CLASSTYPE_INLINE_FRIENDS (type) = NULL;
4260 }
4261
4262 /* Add OFFSET to all base types of BINFO which is a base in the
4263    hierarchy dominated by T.
4264
4265    OFFSET, which is a type offset, is number of bytes.  */
4266
4267 static void
4268 propagate_binfo_offsets (tree binfo, tree offset)
4269 {
4270   int i;
4271   tree primary_binfo;
4272   tree base_binfo;
4273
4274   /* Update BINFO's offset.  */
4275   BINFO_OFFSET (binfo)
4276     = convert (sizetype,
4277                size_binop (PLUS_EXPR,
4278                            convert (ssizetype, BINFO_OFFSET (binfo)),
4279                            offset));
4280
4281   /* Find the primary base class.  */
4282   primary_binfo = get_primary_binfo (binfo);
4283
4284   if (primary_binfo && BINFO_INHERITANCE_CHAIN (primary_binfo) == binfo)
4285     propagate_binfo_offsets (primary_binfo, offset);
4286
4287   /* Scan all of the bases, pushing the BINFO_OFFSET adjust
4288      downwards.  */
4289   for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
4290     {
4291       /* Don't do the primary base twice.  */
4292       if (base_binfo == primary_binfo)
4293         continue;
4294
4295       if (BINFO_VIRTUAL_P (base_binfo))
4296         continue;
4297
4298       propagate_binfo_offsets (base_binfo, offset);
4299     }
4300 }
4301
4302 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T.  Update
4303    TYPE_ALIGN and TYPE_SIZE for T.  OFFSETS gives the location of
4304    empty subobjects of T.  */
4305
4306 static void
4307 layout_virtual_bases (record_layout_info rli, splay_tree offsets)
4308 {
4309   tree vbase;
4310   tree t = rli->t;
4311   bool first_vbase = true;
4312   tree *next_field;
4313
4314   if (BINFO_N_BASE_BINFOS (TYPE_BINFO (t)) == 0)
4315     return;
4316
4317   if (!abi_version_at_least(2))
4318     {
4319       /* In G++ 3.2, we incorrectly rounded the size before laying out
4320          the virtual bases.  */
4321       finish_record_layout (rli, /*free_p=*/false);
4322 #ifdef STRUCTURE_SIZE_BOUNDARY
4323       /* Packed structures don't need to have minimum size.  */
4324       if (! TYPE_PACKED (t))
4325         TYPE_ALIGN (t) = MAX (TYPE_ALIGN (t), (unsigned) STRUCTURE_SIZE_BOUNDARY);
4326 #endif
4327       rli->offset = TYPE_SIZE_UNIT (t);
4328       rli->bitpos = bitsize_zero_node;
4329       rli->record_align = TYPE_ALIGN (t);
4330     }
4331
4332   /* Find the last field.  The artificial fields created for virtual
4333      bases will go after the last extant field to date.  */
4334   next_field = &TYPE_FIELDS (t);
4335   while (*next_field)
4336     next_field = &TREE_CHAIN (*next_field);
4337
4338   /* Go through the virtual bases, allocating space for each virtual
4339      base that is not already a primary base class.  These are
4340      allocated in inheritance graph order.  */
4341   for (vbase = TYPE_BINFO (t); vbase; vbase = TREE_CHAIN (vbase))
4342     {
4343       if (!BINFO_VIRTUAL_P (vbase))
4344         continue;
4345
4346       if (!BINFO_PRIMARY_P (vbase))
4347         {
4348           tree basetype = TREE_TYPE (vbase);
4349
4350           /* This virtual base is not a primary base of any class in the
4351              hierarchy, so we have to add space for it.  */
4352           next_field = build_base_field (rli, vbase,
4353                                          offsets, next_field);
4354
4355           /* If the first virtual base might have been placed at a
4356              lower address, had we started from CLASSTYPE_SIZE, rather
4357              than TYPE_SIZE, issue a warning.  There can be both false
4358              positives and false negatives from this warning in rare
4359              cases; to deal with all the possibilities would probably
4360              require performing both layout algorithms and comparing
4361              the results which is not particularly tractable.  */
4362           if (warn_abi
4363               && first_vbase
4364               && (tree_int_cst_lt
4365                   (size_binop (CEIL_DIV_EXPR,
4366                                round_up (CLASSTYPE_SIZE (t),
4367                                          CLASSTYPE_ALIGN (basetype)),
4368                                bitsize_unit_node),
4369                    BINFO_OFFSET (vbase))))
4370             warning (OPT_Wabi,
4371                      "offset of virtual base %qT is not ABI-compliant and "
4372                      "may change in a future version of GCC",
4373                      basetype);
4374
4375           first_vbase = false;
4376         }
4377     }
4378 }
4379
4380 /* Returns the offset of the byte just past the end of the base class
4381    BINFO.  */
4382
4383 static tree
4384 end_of_base (tree binfo)
4385 {
4386   tree size;
4387
4388   if (is_empty_class (BINFO_TYPE (binfo)))
4389     /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
4390        allocate some space for it. It cannot have virtual bases, so
4391        TYPE_SIZE_UNIT is fine.  */
4392     size = TYPE_SIZE_UNIT (BINFO_TYPE (binfo));
4393   else
4394     size = CLASSTYPE_SIZE_UNIT (BINFO_TYPE (binfo));
4395
4396   return size_binop (PLUS_EXPR, BINFO_OFFSET (binfo), size);
4397 }
4398
4399 /* Returns the offset of the byte just past the end of the base class
4400    with the highest offset in T.  If INCLUDE_VIRTUALS_P is zero, then
4401    only non-virtual bases are included.  */
4402
4403 static tree
4404 end_of_class (tree t, int include_virtuals_p)
4405 {
4406   tree result = size_zero_node;
4407   VEC(tree,gc) *vbases;
4408   tree binfo;
4409   tree base_binfo;
4410   tree offset;
4411   int i;
4412
4413   for (binfo = TYPE_BINFO (t), i = 0;
4414        BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
4415     {
4416       if (!include_virtuals_p
4417           && BINFO_VIRTUAL_P (base_binfo)
4418           && (!BINFO_PRIMARY_P (base_binfo)
4419               || BINFO_INHERITANCE_CHAIN (base_binfo) != TYPE_BINFO (t)))
4420         continue;
4421
4422       offset = end_of_base (base_binfo);
4423       if (INT_CST_LT_UNSIGNED (result, offset))
4424         result = offset;
4425     }
4426
4427   /* G++ 3.2 did not check indirect virtual bases.  */
4428   if (abi_version_at_least (2) && include_virtuals_p)
4429     for (vbases = CLASSTYPE_VBASECLASSES (t), i = 0;
4430          VEC_iterate (tree, vbases, i, base_binfo); i++)
4431       {
4432         offset = end_of_base (base_binfo);
4433         if (INT_CST_LT_UNSIGNED (result, offset))
4434           result = offset;
4435       }
4436
4437   return result;
4438 }
4439
4440 /* Warn about bases of T that are inaccessible because they are
4441    ambiguous.  For example:
4442
4443      struct S {};
4444      struct T : public S {};
4445      struct U : public S, public T {};
4446
4447    Here, `(S*) new U' is not allowed because there are two `S'
4448    subobjects of U.  */
4449
4450 static void
4451 warn_about_ambiguous_bases (tree t)
4452 {
4453   int i;
4454   VEC(tree,gc) *vbases;
4455   tree basetype;
4456   tree binfo;
4457   tree base_binfo;
4458
4459   /* If there are no repeated bases, nothing can be ambiguous.  */
4460   if (!CLASSTYPE_REPEATED_BASE_P (t))
4461     return;
4462
4463   /* Check direct bases.  */
4464   for (binfo = TYPE_BINFO (t), i = 0;
4465        BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
4466     {
4467       basetype = BINFO_TYPE (base_binfo);
4468
4469       if (!lookup_base (t, basetype, ba_unique | ba_quiet, NULL))
4470         warning (0, "direct base %qT inaccessible in %qT due to ambiguity",
4471                  basetype, t);
4472     }
4473
4474   /* Check for ambiguous virtual bases.  */
4475   if (extra_warnings)
4476     for (vbases = CLASSTYPE_VBASECLASSES (t), i = 0;
4477          VEC_iterate (tree, vbases, i, binfo); i++)
4478       {
4479         basetype = BINFO_TYPE (binfo);
4480
4481         if (!lookup_base (t, basetype, ba_unique | ba_quiet, NULL))
4482           warning (OPT_Wextra, "virtual base %qT inaccessible in %qT due to ambiguity",
4483                    basetype, t);
4484       }
4485 }
4486
4487 /* Compare two INTEGER_CSTs K1 and K2.  */
4488
4489 static int
4490 splay_tree_compare_integer_csts (splay_tree_key k1, splay_tree_key k2)
4491 {
4492   return tree_int_cst_compare ((tree) k1, (tree) k2);
4493 }
4494
4495 /* Increase the size indicated in RLI to account for empty classes
4496    that are "off the end" of the class.  */
4497
4498 static void
4499 include_empty_classes (record_layout_info rli)
4500 {
4501   tree eoc;
4502   tree rli_size;
4503
4504   /* It might be the case that we grew the class to allocate a
4505      zero-sized base class.  That won't be reflected in RLI, yet,
4506      because we are willing to overlay multiple bases at the same
4507      offset.  However, now we need to make sure that RLI is big enough
4508      to reflect the entire class.  */
4509   eoc = end_of_class (rli->t,
4510                       CLASSTYPE_AS_BASE (rli->t) != NULL_TREE);
4511   rli_size = rli_size_unit_so_far (rli);
4512   if (TREE_CODE (rli_size) == INTEGER_CST
4513       && INT_CST_LT_UNSIGNED (rli_size, eoc))
4514     {
4515       if (!abi_version_at_least (2))
4516         /* In version 1 of the ABI, the size of a class that ends with
4517            a bitfield was not rounded up to a whole multiple of a
4518            byte.  Because rli_size_unit_so_far returns only the number
4519            of fully allocated bytes, any extra bits were not included
4520            in the size.  */
4521         rli->bitpos = round_down (rli->bitpos, BITS_PER_UNIT);
4522       else
4523         /* The size should have been rounded to a whole byte.  */
4524         gcc_assert (tree_int_cst_equal
4525                     (rli->bitpos, round_down (rli->bitpos, BITS_PER_UNIT)));
4526       rli->bitpos
4527         = size_binop (PLUS_EXPR,
4528                       rli->bitpos,
4529                       size_binop (MULT_EXPR,
4530                                   convert (bitsizetype,
4531                                            size_binop (MINUS_EXPR,
4532                                                        eoc, rli_size)),
4533                                   bitsize_int (BITS_PER_UNIT)));
4534       normalize_rli (rli);
4535     }
4536 }
4537
4538 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T.  Calculate
4539    BINFO_OFFSETs for all of the base-classes.  Position the vtable
4540    pointer.  Accumulate declared virtual functions on VIRTUALS_P.  */
4541
4542 static void
4543 layout_class_type (tree t, tree *virtuals_p)
4544 {
4545   tree non_static_data_members;
4546   tree field;
4547   tree vptr;
4548   record_layout_info rli;
4549   /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
4550      types that appear at that offset.  */
4551   splay_tree empty_base_offsets;
4552   /* True if the last field layed out was a bit-field.  */
4553   bool last_field_was_bitfield = false;
4554   /* The location at which the next field should be inserted.  */
4555   tree *next_field;
4556   /* T, as a base class.  */
4557   tree base_t;
4558
4559   /* Keep track of the first non-static data member.  */
4560   non_static_data_members = TYPE_FIELDS (t);
4561
4562   /* Start laying out the record.  */
4563   rli = start_record_layout (t);
4564
4565   /* Mark all the primary bases in the hierarchy.  */
4566   determine_primary_bases (t);
4567
4568   /* Create a pointer to our virtual function table.  */
4569   vptr = create_vtable_ptr (t, virtuals_p);
4570
4571   /* The vptr is always the first thing in the class.  */
4572   if (vptr)
4573     {
4574       TREE_CHAIN (vptr) = TYPE_FIELDS (t);
4575       TYPE_FIELDS (t) = vptr;
4576       next_field = &TREE_CHAIN (vptr);
4577       place_field (rli, vptr);
4578     }
4579   else
4580     next_field = &TYPE_FIELDS (t);
4581
4582   /* Build FIELD_DECLs for all of the non-virtual base-types.  */
4583   empty_base_offsets = splay_tree_new (splay_tree_compare_integer_csts,
4584                                        NULL, NULL);
4585   build_base_fields (rli, empty_base_offsets, next_field);
4586
4587   /* Layout the non-static data members.  */
4588   for (field = non_static_data_members; field; field = TREE_CHAIN (field))
4589     {
4590       tree type;
4591       tree padding;
4592
4593       /* We still pass things that aren't non-static data members to
4594          the back end, in case it wants to do something with them.  */
4595       if (TREE_CODE (field) != FIELD_DECL)
4596         {
4597           place_field (rli, field);
4598           /* If the static data member has incomplete type, keep track
4599              of it so that it can be completed later.  (The handling
4600              of pending statics in finish_record_layout is
4601              insufficient; consider:
4602
4603                struct S1;
4604                struct S2 { static S1 s1; };
4605
4606              At this point, finish_record_layout will be called, but
4607              S1 is still incomplete.)  */
4608           if (TREE_CODE (field) == VAR_DECL)
4609             {
4610               maybe_register_incomplete_var (field);
4611               /* The visibility of static data members is determined
4612                  at their point of declaration, not their point of
4613                  definition.  */
4614               determine_visibility (field);
4615             }
4616           continue;
4617         }
4618
4619       type = TREE_TYPE (field);
4620       if (type == error_mark_node)
4621         continue;
4622
4623       padding = NULL_TREE;
4624
4625       /* If this field is a bit-field whose width is greater than its
4626          type, then there are some special rules for allocating
4627          it.  */
4628       if (DECL_C_BIT_FIELD (field)
4629           && INT_CST_LT (TYPE_SIZE (type), DECL_SIZE (field)))
4630         {
4631           integer_type_kind itk;
4632           tree integer_type;
4633           bool was_unnamed_p = false;
4634           /* We must allocate the bits as if suitably aligned for the
4635              longest integer type that fits in this many bits.  type
4636              of the field.  Then, we are supposed to use the left over
4637              bits as additional padding.  */
4638           for (itk = itk_char; itk != itk_none; ++itk)
4639             if (INT_CST_LT (DECL_SIZE (field),
4640                             TYPE_SIZE (integer_types[itk])))
4641               break;
4642
4643           /* ITK now indicates a type that is too large for the
4644              field.  We have to back up by one to find the largest
4645              type that fits.  */
4646           integer_type = integer_types[itk - 1];
4647
4648           /* Figure out how much additional padding is required.  GCC
4649              3.2 always created a padding field, even if it had zero
4650              width.  */
4651           if (!abi_version_at_least (2)
4652               || INT_CST_LT (TYPE_SIZE (integer_type), DECL_SIZE (field)))
4653             {
4654               if (abi_version_at_least (2) && TREE_CODE (t) == UNION_TYPE)
4655                 /* In a union, the padding field must have the full width
4656                    of the bit-field; all fields start at offset zero.  */
4657                 padding = DECL_SIZE (field);
4658               else
4659                 {
4660                   if (TREE_CODE (t) == UNION_TYPE)
4661                     warning (OPT_Wabi, "size assigned to %qT may not be "
4662                              "ABI-compliant and may change in a future "
4663                              "version of GCC",
4664                              t);
4665                   padding = size_binop (MINUS_EXPR, DECL_SIZE (field),
4666                                         TYPE_SIZE (integer_type));
4667                 }
4668             }
4669 #ifdef PCC_BITFIELD_TYPE_MATTERS
4670           /* An unnamed bitfield does not normally affect the
4671              alignment of the containing class on a target where
4672              PCC_BITFIELD_TYPE_MATTERS.  But, the C++ ABI does not
4673              make any exceptions for unnamed bitfields when the
4674              bitfields are longer than their types.  Therefore, we
4675              temporarily give the field a name.  */
4676           if (PCC_BITFIELD_TYPE_MATTERS && !DECL_NAME (field))
4677             {
4678               was_unnamed_p = true;
4679               DECL_NAME (field) = make_anon_name ();
4680             }
4681 #endif
4682           DECL_SIZE (field) = TYPE_SIZE (integer_type);
4683           DECL_ALIGN (field) = TYPE_ALIGN (integer_type);
4684           DECL_USER_ALIGN (field) = TYPE_USER_ALIGN (integer_type);
4685           layout_nonempty_base_or_field (rli, field, NULL_TREE,
4686                                          empty_base_offsets);
4687           if (was_unnamed_p)
4688             DECL_NAME (field) = NULL_TREE;
4689           /* Now that layout has been performed, set the size of the
4690              field to the size of its declared type; the rest of the
4691              field is effectively invisible.  */
4692           DECL_SIZE (field) = TYPE_SIZE (type);
4693           /* We must also reset the DECL_MODE of the field.  */
4694           if (abi_version_at_least (2))
4695             DECL_MODE (field) = TYPE_MODE (type);
4696           else if (warn_abi
4697                    && DECL_MODE (field) != TYPE_MODE (type))
4698             /* Versions of G++ before G++ 3.4 did not reset the
4699                DECL_MODE.  */
4700             warning (OPT_Wabi,
4701                      "the offset of %qD may not be ABI-compliant and may "
4702                      "change in a future version of GCC", field);
4703         }
4704       else
4705         layout_nonempty_base_or_field (rli, field, NULL_TREE,
4706                                        empty_base_offsets);
4707
4708       /* Remember the location of any empty classes in FIELD.  */
4709       if (abi_version_at_least (2))
4710         record_subobject_offsets (TREE_TYPE (field),
4711                                   byte_position(field),
4712                                   empty_base_offsets,
4713                                   /*is_data_member=*/true);
4714
4715       /* If a bit-field does not immediately follow another bit-field,
4716          and yet it starts in the middle of a byte, we have failed to
4717          comply with the ABI.  */
4718       if (warn_abi
4719           && DECL_C_BIT_FIELD (field)
4720           /* The TREE_NO_WARNING flag gets set by Objective-C when
4721              laying out an Objective-C class.  The ObjC ABI differs
4722              from the C++ ABI, and so we do not want a warning
4723              here.  */
4724           && !TREE_NO_WARNING (field)
4725           && !last_field_was_bitfield
4726           && !integer_zerop (size_binop (TRUNC_MOD_EXPR,
4727                                          DECL_FIELD_BIT_OFFSET (field),
4728                                          bitsize_unit_node)))
4729         warning (OPT_Wabi, "offset of %q+D is not ABI-compliant and may "
4730                  "change in a future version of GCC", field);
4731
4732       /* G++ used to use DECL_FIELD_OFFSET as if it were the byte
4733          offset of the field.  */
4734       if (warn_abi
4735           && !tree_int_cst_equal (DECL_FIELD_OFFSET (field),
4736                                   byte_position (field))
4737           && contains_empty_class_p (TREE_TYPE (field)))
4738         warning (OPT_Wabi, "%q+D contains empty classes which may cause base "
4739                  "classes to be placed at different locations in a "
4740                  "future version of GCC", field);
4741
4742       /* The middle end uses the type of expressions to determine the
4743          possible range of expression values.  In order to optimize
4744          "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
4745          must be made aware of the width of "i", via its type.
4746
4747          Because C++ does not have integer types of arbitrary width,
4748          we must (for the purposes of the front end) convert from the
4749          type assigned here to the declared type of the bitfield
4750          whenever a bitfield expression is used as an rvalue.
4751          Similarly, when assigning a value to a bitfield, the value
4752          must be converted to the type given the bitfield here.  */
4753       if (DECL_C_BIT_FIELD (field))
4754         {
4755           tree ftype;
4756           unsigned HOST_WIDE_INT width;
4757           ftype = TREE_TYPE (field);
4758           width = tree_low_cst (DECL_SIZE (field), /*unsignedp=*/1);
4759           if (width != TYPE_PRECISION (ftype))
4760             TREE_TYPE (field)
4761               = c_build_bitfield_integer_type (width,
4762                                                TYPE_UNSIGNED (ftype));
4763         }
4764
4765       /* If we needed additional padding after this field, add it
4766          now.  */
4767       if (padding)
4768         {
4769           tree padding_field;
4770
4771           padding_field = build_decl (FIELD_DECL,
4772                                       NULL_TREE,
4773                                       char_type_node);
4774           DECL_BIT_FIELD (padding_field) = 1;
4775           DECL_SIZE (padding_field) = padding;
4776           DECL_CONTEXT (padding_field) = t;
4777           DECL_ARTIFICIAL (padding_field) = 1;
4778           DECL_IGNORED_P (padding_field) = 1;
4779           layout_nonempty_base_or_field (rli, padding_field,
4780                                          NULL_TREE,
4781                                          empty_base_offsets);
4782         }
4783
4784       last_field_was_bitfield = DECL_C_BIT_FIELD (field);
4785     }
4786
4787   if (abi_version_at_least (2) && !integer_zerop (rli->bitpos))
4788     {
4789       /* Make sure that we are on a byte boundary so that the size of
4790          the class without virtual bases will always be a round number
4791          of bytes.  */
4792       rli->bitpos = round_up (rli->bitpos, BITS_PER_UNIT);
4793       normalize_rli (rli);
4794     }
4795
4796   /* G++ 3.2 does not allow virtual bases to be overlaid with tail
4797      padding.  */
4798   if (!abi_version_at_least (2))
4799     include_empty_classes(rli);
4800
4801   /* Delete all zero-width bit-fields from the list of fields.  Now
4802      that the type is laid out they are no longer important.  */
4803   remove_zero_width_bit_fields (t);
4804
4805   /* Create the version of T used for virtual bases.  We do not use
4806      make_aggr_type for this version; this is an artificial type.  For
4807      a POD type, we just reuse T.  */
4808   if (CLASSTYPE_NON_POD_P (t) || CLASSTYPE_EMPTY_P (t))
4809     {
4810       base_t = make_node (TREE_CODE (t));
4811
4812       /* Set the size and alignment for the new type.  In G++ 3.2, all
4813          empty classes were considered to have size zero when used as
4814          base classes.  */
4815       if (!abi_version_at_least (2) && CLASSTYPE_EMPTY_P (t))
4816         {
4817           TYPE_SIZE (base_t) = bitsize_zero_node;
4818           TYPE_SIZE_UNIT (base_t) = size_zero_node;
4819           if (warn_abi && !integer_zerop (rli_size_unit_so_far (rli)))
4820             warning (OPT_Wabi,
4821                      "layout of classes derived from empty class %qT "
4822                      "may change in a future version of GCC",
4823                      t);
4824         }
4825       else
4826         {
4827           tree eoc;
4828
4829           /* If the ABI version is not at least two, and the last
4830              field was a bit-field, RLI may not be on a byte
4831              boundary.  In particular, rli_size_unit_so_far might
4832              indicate the last complete byte, while rli_size_so_far
4833              indicates the total number of bits used.  Therefore,
4834              rli_size_so_far, rather than rli_size_unit_so_far, is
4835              used to compute TYPE_SIZE_UNIT.  */
4836           eoc = end_of_class (t, /*include_virtuals_p=*/0);
4837           TYPE_SIZE_UNIT (base_t)
4838             = size_binop (MAX_EXPR,
4839                           convert (sizetype,
4840                                    size_binop (CEIL_DIV_EXPR,
4841                                                rli_size_so_far (rli),
4842                                                bitsize_int (BITS_PER_UNIT))),
4843                           eoc);
4844           TYPE_SIZE (base_t)
4845             = size_binop (MAX_EXPR,
4846                           rli_size_so_far (rli),
4847                           size_binop (MULT_EXPR,
4848                                       convert (bitsizetype, eoc),
4849                                       bitsize_int (BITS_PER_UNIT)));
4850         }
4851       TYPE_ALIGN (base_t) = rli->record_align;
4852       TYPE_USER_ALIGN (base_t) = TYPE_USER_ALIGN (t);
4853
4854       /* Copy the fields from T.  */
4855       next_field = &TYPE_FIELDS (base_t);
4856       for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
4857         if (TREE_CODE (field) == FIELD_DECL)
4858           {
4859             *next_field = build_decl (FIELD_DECL,
4860                                       DECL_NAME (field),
4861                                       TREE_TYPE (field));
4862             DECL_CONTEXT (*next_field) = base_t;
4863             DECL_FIELD_OFFSET (*next_field) = DECL_FIELD_OFFSET (field);
4864             DECL_FIELD_BIT_OFFSET (*next_field)
4865               = DECL_FIELD_BIT_OFFSET (field);
4866             DECL_SIZE (*next_field) = DECL_SIZE (field);
4867             DECL_MODE (*next_field) = DECL_MODE (field);
4868             next_field = &TREE_CHAIN (*next_field);
4869           }
4870
4871       /* Record the base version of the type.  */
4872       CLASSTYPE_AS_BASE (t) = base_t;
4873       TYPE_CONTEXT (base_t) = t;
4874     }
4875   else
4876     CLASSTYPE_AS_BASE (t) = t;
4877
4878   /* Every empty class contains an empty class.  */
4879   if (CLASSTYPE_EMPTY_P (t))
4880     CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
4881
4882   /* Set the TYPE_DECL for this type to contain the right
4883      value for DECL_OFFSET, so that we can use it as part
4884      of a COMPONENT_REF for multiple inheritance.  */
4885   layout_decl (TYPE_MAIN_DECL (t), 0);
4886
4887   /* Now fix up any virtual base class types that we left lying
4888      around.  We must get these done before we try to lay out the
4889      virtual function table.  As a side-effect, this will remove the
4890      base subobject fields.  */
4891   layout_virtual_bases (rli, empty_base_offsets);
4892
4893   /* Make sure that empty classes are reflected in RLI at this
4894      point.  */
4895   include_empty_classes(rli);
4896
4897   /* Make sure not to create any structures with zero size.  */
4898   if (integer_zerop (rli_size_unit_so_far (rli)) && CLASSTYPE_EMPTY_P (t))
4899     place_field (rli,
4900                  build_decl (FIELD_DECL, NULL_TREE, char_type_node));
4901
4902   /* Let the back end lay out the type.  */
4903   finish_record_layout (rli, /*free_p=*/true);
4904
4905   /* Warn about bases that can't be talked about due to ambiguity.  */
4906   warn_about_ambiguous_bases (t);
4907
4908   /* Now that we're done with layout, give the base fields the real types.  */
4909   for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
4910     if (DECL_ARTIFICIAL (field) && IS_FAKE_BASE_TYPE (TREE_TYPE (field)))
4911       TREE_TYPE (field) = TYPE_CONTEXT (TREE_TYPE (field));
4912
4913   /* Clean up.  */
4914   splay_tree_delete (empty_base_offsets);
4915
4916   if (CLASSTYPE_EMPTY_P (t)
4917       && tree_int_cst_lt (sizeof_biggest_empty_class,
4918                           TYPE_SIZE_UNIT (t)))
4919     sizeof_biggest_empty_class = TYPE_SIZE_UNIT (t);
4920 }
4921
4922 /* Determine the "key method" for the class type indicated by TYPE,
4923    and set CLASSTYPE_KEY_METHOD accordingly.  */
4924
4925 void
4926 determine_key_method (tree type)
4927 {
4928   tree method;
4929
4930   if (TYPE_FOR_JAVA (type)
4931       || processing_template_decl
4932       || CLASSTYPE_TEMPLATE_INSTANTIATION (type)
4933       || CLASSTYPE_INTERFACE_KNOWN (type))
4934     return;
4935
4936   /* The key method is the first non-pure virtual function that is not
4937      inline at the point of class definition.  On some targets the
4938      key function may not be inline; those targets should not call
4939      this function until the end of the translation unit.  */
4940   for (method = TYPE_METHODS (type); method != NULL_TREE;
4941        method = TREE_CHAIN (method))
4942     if (DECL_VINDEX (method) != NULL_TREE
4943         && ! DECL_DECLARED_INLINE_P (method)
4944         && ! DECL_PURE_VIRTUAL_P (method))
4945       {
4946         CLASSTYPE_KEY_METHOD (type) = method;
4947         break;
4948       }
4949
4950   return;
4951 }
4952
4953 /* Perform processing required when the definition of T (a class type)
4954    is complete.  */
4955
4956 void
4957 finish_struct_1 (tree t)
4958 {
4959   tree x;
4960   /* A TREE_LIST.  The TREE_VALUE of each node is a FUNCTION_DECL.  */
4961   tree virtuals = NULL_TREE;
4962   int n_fields = 0;
4963
4964   if (COMPLETE_TYPE_P (t))
4965     {
4966       gcc_assert (IS_AGGR_TYPE (t));
4967       error ("redefinition of %q#T", t);
4968       popclass ();
4969       return;
4970     }
4971
4972   /* If this type was previously laid out as a forward reference,
4973      make sure we lay it out again.  */
4974   TYPE_SIZE (t) = NULL_TREE;
4975   CLASSTYPE_PRIMARY_BINFO (t) = NULL_TREE;
4976
4977   fixup_inline_methods (t);
4978
4979   /* Make assumptions about the class; we'll reset the flags if
4980      necessary.  */
4981   CLASSTYPE_EMPTY_P (t) = 1;
4982   CLASSTYPE_NEARLY_EMPTY_P (t) = 1;
4983   CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 0;
4984
4985   /* Do end-of-class semantic processing: checking the validity of the
4986      bases and members and add implicitly generated methods.  */
4987   check_bases_and_members (t);
4988
4989   /* Find the key method.  */
4990   if (TYPE_CONTAINS_VPTR_P (t))
4991     {
4992       /* The Itanium C++ ABI permits the key method to be chosen when
4993          the class is defined -- even though the key method so
4994          selected may later turn out to be an inline function.  On
4995          some systems (such as ARM Symbian OS) the key method cannot
4996          be determined until the end of the translation unit.  On such
4997          systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
4998          will cause the class to be added to KEYED_CLASSES.  Then, in
4999          finish_file we will determine the key method.  */
5000       if (targetm.cxx.key_method_may_be_inline ())
5001         determine_key_method (t);
5002
5003       /* If a polymorphic class has no key method, we may emit the vtable
5004          in every translation unit where the class definition appears.  */
5005       if (CLASSTYPE_KEY_METHOD (t) == NULL_TREE)
5006         keyed_classes = tree_cons (NULL_TREE, t, keyed_classes);
5007     }
5008
5009   /* Layout the class itself.  */
5010   layout_class_type (t, &virtuals);
5011   if (CLASSTYPE_AS_BASE (t) != t)
5012     /* We use the base type for trivial assignments, and hence it
5013        needs a mode.  */
5014     compute_record_mode (CLASSTYPE_AS_BASE (t));
5015
5016   virtuals = modify_all_vtables (t, nreverse (virtuals));
5017
5018   /* If necessary, create the primary vtable for this class.  */
5019   if (virtuals || TYPE_CONTAINS_VPTR_P (t))
5020     {
5021       /* We must enter these virtuals into the table.  */
5022       if (!CLASSTYPE_HAS_PRIMARY_BASE_P (t))
5023         build_primary_vtable (NULL_TREE, t);
5024       else if (! BINFO_NEW_VTABLE_MARKED (TYPE_BINFO (t)))
5025         /* Here we know enough to change the type of our virtual
5026            function table, but we will wait until later this function.  */
5027         build_primary_vtable (CLASSTYPE_PRIMARY_BINFO (t), t);
5028     }
5029
5030   if (TYPE_CONTAINS_VPTR_P (t))
5031     {
5032       int vindex;
5033       tree fn;
5034
5035       if (BINFO_VTABLE (TYPE_BINFO (t)))
5036         gcc_assert (DECL_VIRTUAL_P (BINFO_VTABLE (TYPE_BINFO (t))));
5037       if (!CLASSTYPE_HAS_PRIMARY_BASE_P (t))
5038         gcc_assert (BINFO_VIRTUALS (TYPE_BINFO (t)) == NULL_TREE);
5039
5040       /* Add entries for virtual functions introduced by this class.  */
5041       BINFO_VIRTUALS (TYPE_BINFO (t))
5042         = chainon (BINFO_VIRTUALS (TYPE_BINFO (t)), virtuals);
5043
5044       /* Set DECL_VINDEX for all functions declared in this class.  */
5045       for (vindex = 0, fn = BINFO_VIRTUALS (TYPE_BINFO (t));
5046            fn;
5047            fn = TREE_CHAIN (fn),
5048              vindex += (TARGET_VTABLE_USES_DESCRIPTORS
5049                         ? TARGET_VTABLE_USES_DESCRIPTORS : 1))
5050         {
5051           tree fndecl = BV_FN (fn);
5052
5053           if (DECL_THUNK_P (fndecl))
5054             /* A thunk. We should never be calling this entry directly
5055                from this vtable -- we'd use the entry for the non
5056                thunk base function.  */
5057             DECL_VINDEX (fndecl) = NULL_TREE;
5058           else if (TREE_CODE (DECL_VINDEX (fndecl)) != INTEGER_CST)
5059             DECL_VINDEX (fndecl) = build_int_cst (NULL_TREE, vindex);
5060         }
5061     }
5062
5063   finish_struct_bits (t);
5064
5065   /* Complete the rtl for any static member objects of the type we're
5066      working on.  */
5067   for (x = TYPE_FIELDS (t); x; x = TREE_CHAIN (x))
5068     if (TREE_CODE (x) == VAR_DECL && TREE_STATIC (x)
5069         && TREE_TYPE (x) != error_mark_node
5070         && same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (x)), t))
5071       DECL_MODE (x) = TYPE_MODE (t);
5072
5073   /* Done with FIELDS...now decide whether to sort these for
5074      faster lookups later.
5075
5076      We use a small number because most searches fail (succeeding
5077      ultimately as the search bores through the inheritance
5078      hierarchy), and we want this failure to occur quickly.  */
5079
5080   n_fields = count_fields (TYPE_FIELDS (t));
5081   if (n_fields > 7)
5082     {
5083       struct sorted_fields_type *field_vec = GGC_NEWVAR
5084          (struct sorted_fields_type,
5085           sizeof (struct sorted_fields_type) + n_fields * sizeof (tree));
5086       field_vec->len = n_fields;
5087       add_fields_to_record_type (TYPE_FIELDS (t), field_vec, 0);
5088       qsort (field_vec->elts, n_fields, sizeof (tree),
5089              field_decl_cmp);
5090       if (! DECL_LANG_SPECIFIC (TYPE_MAIN_DECL (t)))
5091         retrofit_lang_decl (TYPE_MAIN_DECL (t));
5092       DECL_SORTED_FIELDS (TYPE_MAIN_DECL (t)) = field_vec;
5093     }
5094
5095   /* Complain if one of the field types requires lower visibility.  */
5096   constrain_class_visibility (t);
5097
5098   /* Make the rtl for any new vtables we have created, and unmark
5099      the base types we marked.  */
5100   finish_vtbls (t);
5101
5102   /* Build the VTT for T.  */
5103   build_vtt (t);
5104
5105   /* This warning does not make sense for Java classes, since they
5106      cannot have destructors.  */
5107   if (!TYPE_FOR_JAVA (t) && warn_nonvdtor && TYPE_POLYMORPHIC_P (t))
5108     {
5109       tree dtor;
5110
5111       dtor = CLASSTYPE_DESTRUCTORS (t);
5112       /* Warn only if the dtor is non-private or the class has
5113          friends.  */
5114       if (/* An implicitly declared destructor is always public.  And,
5115              if it were virtual, we would have created it by now.  */
5116           !dtor
5117           || (!DECL_VINDEX (dtor)
5118               && (!TREE_PRIVATE (dtor)
5119                   || CLASSTYPE_FRIEND_CLASSES (t)
5120                   || DECL_FRIENDLIST (TYPE_MAIN_DECL (t)))))
5121         warning (0, "%q#T has virtual functions but non-virtual destructor",
5122                  t);
5123     }
5124
5125   complete_vars (t);
5126
5127   if (warn_overloaded_virtual)
5128     warn_hidden (t);
5129
5130   /* Class layout, assignment of virtual table slots, etc., is now
5131      complete.  Give the back end a chance to tweak the visibility of
5132      the class or perform any other required target modifications.  */
5133   targetm.cxx.adjust_class_at_definition (t);
5134
5135   maybe_suppress_debug_info (t);
5136
5137   dump_class_hierarchy (t);
5138
5139   /* Finish debugging output for this type.  */
5140   rest_of_type_compilation (t, ! LOCAL_CLASS_P (t));
5141 }
5142
5143 /* When T was built up, the member declarations were added in reverse
5144    order.  Rearrange them to declaration order.  */
5145
5146 void
5147 unreverse_member_declarations (tree t)
5148 {
5149   tree next;
5150   tree prev;
5151   tree x;
5152
5153   /* The following lists are all in reverse order.  Put them in
5154      declaration order now.  */
5155   TYPE_METHODS (t) = nreverse (TYPE_METHODS (t));
5156   CLASSTYPE_DECL_LIST (t) = nreverse (CLASSTYPE_DECL_LIST (t));
5157
5158   /* Actually, for the TYPE_FIELDS, only the non TYPE_DECLs are in
5159      reverse order, so we can't just use nreverse.  */
5160   prev = NULL_TREE;
5161   for (x = TYPE_FIELDS (t);
5162        x && TREE_CODE (x) != TYPE_DECL;
5163        x = next)
5164     {
5165       next = TREE_CHAIN (x);
5166       TREE_CHAIN (x) = prev;
5167       prev = x;
5168     }
5169   if (prev)
5170     {
5171       TREE_CHAIN (TYPE_FIELDS (t)) = x;
5172       if (prev)
5173         TYPE_FIELDS (t) = prev;
5174     }
5175 }
5176
5177 tree
5178 finish_struct (tree t, tree attributes)
5179 {
5180   location_t saved_loc = input_location;
5181
5182   /* Now that we've got all the field declarations, reverse everything
5183      as necessary.  */
5184   unreverse_member_declarations (t);
5185
5186   cplus_decl_attributes (&t, attributes, (int) ATTR_FLAG_TYPE_IN_PLACE);
5187
5188   /* Nadger the current location so that diagnostics point to the start of
5189      the struct, not the end.  */
5190   input_location = DECL_SOURCE_LOCATION (TYPE_NAME (t));
5191
5192   if (processing_template_decl)
5193     {
5194       tree x;
5195
5196       finish_struct_methods (t);
5197       TYPE_SIZE (t) = bitsize_zero_node;
5198       TYPE_SIZE_UNIT (t) = size_zero_node;
5199
5200       /* We need to emit an error message if this type was used as a parameter
5201          and it is an abstract type, even if it is a template. We construct
5202          a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
5203          account and we call complete_vars with this type, which will check
5204          the PARM_DECLS. Note that while the type is being defined,
5205          CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
5206          (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it.  */
5207       CLASSTYPE_PURE_VIRTUALS (t) = NULL;
5208       for (x = TYPE_METHODS (t); x; x = TREE_CHAIN (x))
5209         if (DECL_PURE_VIRTUAL_P (x))
5210           VEC_safe_push (tree, gc, CLASSTYPE_PURE_VIRTUALS (t), x);
5211       complete_vars (t);
5212     }
5213   else
5214     finish_struct_1 (t);
5215
5216   input_location = saved_loc;
5217
5218   TYPE_BEING_DEFINED (t) = 0;
5219
5220   if (current_class_type)
5221     popclass ();
5222   else
5223     error ("trying to finish struct, but kicked out due to previous parse errors");
5224
5225   if (processing_template_decl && at_function_scope_p ())
5226     add_stmt (build_min (TAG_DEFN, t));
5227
5228   return t;
5229 }
5230 \f
5231 /* Return the dynamic type of INSTANCE, if known.
5232    Used to determine whether the virtual function table is needed
5233    or not.
5234
5235    *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
5236    of our knowledge of its type.  *NONNULL should be initialized
5237    before this function is called.  */
5238
5239 static tree
5240 fixed_type_or_null (tree instance, int* nonnull, int* cdtorp)
5241 {
5242   switch (TREE_CODE (instance))
5243     {
5244     case INDIRECT_REF:
5245       if (POINTER_TYPE_P (TREE_TYPE (instance)))
5246         return NULL_TREE;
5247       else
5248         return fixed_type_or_null (TREE_OPERAND (instance, 0),
5249                                    nonnull, cdtorp);
5250
5251     case CALL_EXPR:
5252       /* This is a call to a constructor, hence it's never zero.  */
5253       if (TREE_HAS_CONSTRUCTOR (instance))
5254         {
5255           if (nonnull)
5256             *nonnull = 1;
5257           return TREE_TYPE (instance);
5258         }
5259       return NULL_TREE;
5260
5261     case SAVE_EXPR:
5262       /* This is a call to a constructor, hence it's never zero.  */
5263       if (TREE_HAS_CONSTRUCTOR (instance))
5264         {
5265           if (nonnull)
5266             *nonnull = 1;
5267           return TREE_TYPE (instance);
5268         }
5269       return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5270
5271     case PLUS_EXPR:
5272     case MINUS_EXPR:
5273       if (TREE_CODE (TREE_OPERAND (instance, 0)) == ADDR_EXPR)
5274         return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5275       if (TREE_CODE (TREE_OPERAND (instance, 1)) == INTEGER_CST)
5276         /* Propagate nonnull.  */
5277         return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5278       return NULL_TREE;
5279
5280     case NOP_EXPR:
5281     case CONVERT_EXPR:
5282       return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5283
5284     case ADDR_EXPR:
5285       instance = TREE_OPERAND (instance, 0);
5286       if (nonnull)
5287         {
5288           /* Just because we see an ADDR_EXPR doesn't mean we're dealing
5289              with a real object -- given &p->f, p can still be null.  */
5290           tree t = get_base_address (instance);
5291           /* ??? Probably should check DECL_WEAK here.  */
5292           if (t && DECL_P (t))
5293             *nonnull = 1;
5294         }
5295       return fixed_type_or_null (instance, nonnull, cdtorp);
5296
5297     case COMPONENT_REF:
5298       /* If this component is really a base class reference, then the field
5299          itself isn't definitive.  */
5300       if (DECL_FIELD_IS_BASE (TREE_OPERAND (instance, 1)))
5301         return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5302       return fixed_type_or_null (TREE_OPERAND (instance, 1), nonnull, cdtorp);
5303
5304     case VAR_DECL:
5305     case FIELD_DECL:
5306       if (TREE_CODE (TREE_TYPE (instance)) == ARRAY_TYPE
5307           && IS_AGGR_TYPE (TREE_TYPE (TREE_TYPE (instance))))
5308         {
5309           if (nonnull)
5310             *nonnull = 1;
5311           return TREE_TYPE (TREE_TYPE (instance));
5312         }
5313       /* fall through...  */
5314     case TARGET_EXPR:
5315     case PARM_DECL:
5316     case RESULT_DECL:
5317       if (IS_AGGR_TYPE (TREE_TYPE (instance)))
5318         {
5319           if (nonnull)
5320             *nonnull = 1;
5321           return TREE_TYPE (instance);
5322         }
5323       else if (instance == current_class_ptr)
5324         {
5325           if (nonnull)
5326             *nonnull = 1;
5327
5328           /* if we're in a ctor or dtor, we know our type.  */
5329           if (DECL_LANG_SPECIFIC (current_function_decl)
5330               && (DECL_CONSTRUCTOR_P (current_function_decl)
5331                   || DECL_DESTRUCTOR_P (current_function_decl)))
5332             {
5333               if (cdtorp)
5334                 *cdtorp = 1;
5335               return TREE_TYPE (TREE_TYPE (instance));
5336             }
5337         }
5338       else if (TREE_CODE (TREE_TYPE (instance)) == REFERENCE_TYPE)
5339         {
5340           /* Reference variables should be references to objects.  */
5341           if (nonnull)
5342             *nonnull = 1;
5343
5344           /* DECL_VAR_MARKED_P is used to prevent recursion; a
5345              variable's initializer may refer to the variable
5346              itself.  */
5347           if (TREE_CODE (instance) == VAR_DECL
5348               && DECL_INITIAL (instance)
5349               && !DECL_VAR_MARKED_P (instance))
5350             {
5351               tree type;
5352               DECL_VAR_MARKED_P (instance) = 1;
5353               type = fixed_type_or_null (DECL_INITIAL (instance),
5354                                          nonnull, cdtorp);
5355               DECL_VAR_MARKED_P (instance) = 0;
5356               return type;
5357             }
5358         }
5359       return NULL_TREE;
5360
5361     default:
5362       return NULL_TREE;
5363     }
5364 }
5365
5366 /* Return nonzero if the dynamic type of INSTANCE is known, and
5367    equivalent to the static type.  We also handle the case where
5368    INSTANCE is really a pointer. Return negative if this is a
5369    ctor/dtor. There the dynamic type is known, but this might not be
5370    the most derived base of the original object, and hence virtual
5371    bases may not be layed out according to this type.
5372
5373    Used to determine whether the virtual function table is needed
5374    or not.
5375
5376    *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
5377    of our knowledge of its type.  *NONNULL should be initialized
5378    before this function is called.  */
5379
5380 int
5381 resolves_to_fixed_type_p (tree instance, int* nonnull)
5382 {
5383   tree t = TREE_TYPE (instance);
5384   int cdtorp = 0;
5385
5386   tree fixed = fixed_type_or_null (instance, nonnull, &cdtorp);
5387   if (fixed == NULL_TREE)
5388     return 0;
5389   if (POINTER_TYPE_P (t))
5390     t = TREE_TYPE (t);
5391   if (!same_type_ignoring_top_level_qualifiers_p (t, fixed))
5392     return 0;
5393   return cdtorp ? -1 : 1;
5394 }
5395
5396 \f
5397 void
5398 init_class_processing (void)
5399 {
5400   current_class_depth = 0;
5401   current_class_stack_size = 10;
5402   current_class_stack
5403     = XNEWVEC (struct class_stack_node, current_class_stack_size);
5404   local_classes = VEC_alloc (tree, gc, 8);
5405   sizeof_biggest_empty_class = size_zero_node;
5406
5407   ridpointers[(int) RID_PUBLIC] = access_public_node;
5408   ridpointers[(int) RID_PRIVATE] = access_private_node;
5409   ridpointers[(int) RID_PROTECTED] = access_protected_node;
5410 }
5411
5412 /* Restore the cached PREVIOUS_CLASS_LEVEL.  */
5413
5414 static void
5415 restore_class_cache (void)
5416 {
5417   tree type;
5418
5419   /* We are re-entering the same class we just left, so we don't
5420      have to search the whole inheritance matrix to find all the
5421      decls to bind again.  Instead, we install the cached
5422      class_shadowed list and walk through it binding names.  */
5423   push_binding_level (previous_class_level);
5424   class_binding_level = previous_class_level;
5425   /* Restore IDENTIFIER_TYPE_VALUE.  */
5426   for (type = class_binding_level->type_shadowed;
5427        type;
5428        type = TREE_CHAIN (type))
5429     SET_IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (type), TREE_TYPE (type));
5430 }
5431
5432 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
5433    appropriate for TYPE.
5434
5435    So that we may avoid calls to lookup_name, we cache the _TYPE
5436    nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
5437
5438    For multiple inheritance, we perform a two-pass depth-first search
5439    of the type lattice.  */
5440
5441 void
5442 pushclass (tree type)
5443 {
5444   class_stack_node_t csn;
5445
5446   type = TYPE_MAIN_VARIANT (type);
5447
5448   /* Make sure there is enough room for the new entry on the stack.  */
5449   if (current_class_depth + 1 >= current_class_stack_size)
5450     {
5451       current_class_stack_size *= 2;
5452       current_class_stack
5453         = XRESIZEVEC (struct class_stack_node, current_class_stack,
5454                       current_class_stack_size);
5455     }
5456
5457   /* Insert a new entry on the class stack.  */
5458   csn = current_class_stack + current_class_depth;
5459   csn->name = current_class_name;
5460   csn->type = current_class_type;
5461   csn->access = current_access_specifier;
5462   csn->names_used = 0;
5463   csn->hidden = 0;
5464   current_class_depth++;
5465
5466   /* Now set up the new type.  */
5467   current_class_name = TYPE_NAME (type);
5468   if (TREE_CODE (current_class_name) == TYPE_DECL)
5469     current_class_name = DECL_NAME (current_class_name);
5470   current_class_type = type;
5471
5472   /* By default, things in classes are private, while things in
5473      structures or unions are public.  */
5474   current_access_specifier = (CLASSTYPE_DECLARED_CLASS (type)
5475                               ? access_private_node
5476                               : access_public_node);
5477
5478   if (previous_class_level
5479       && type != previous_class_level->this_entity
5480       && current_class_depth == 1)
5481     {
5482       /* Forcibly remove any old class remnants.  */
5483       invalidate_class_lookup_cache ();
5484     }
5485
5486   if (!previous_class_level
5487       || type != previous_class_level->this_entity
5488       || current_class_depth > 1)
5489     pushlevel_class ();
5490   else
5491     restore_class_cache ();
5492 }
5493
5494 /* When we exit a toplevel class scope, we save its binding level so
5495    that we can restore it quickly.  Here, we've entered some other
5496    class, so we must invalidate our cache.  */
5497
5498 void
5499 invalidate_class_lookup_cache (void)
5500 {
5501   previous_class_level = NULL;
5502 }
5503
5504 /* Get out of the current class scope. If we were in a class scope
5505    previously, that is the one popped to.  */
5506
5507 void
5508 popclass (void)
5509 {
5510   poplevel_class ();
5511
5512   current_class_depth--;
5513   current_class_name = current_class_stack[current_class_depth].name;
5514   current_class_type = current_class_stack[current_class_depth].type;
5515   current_access_specifier = current_class_stack[current_class_depth].access;
5516   if (current_class_stack[current_class_depth].names_used)
5517     splay_tree_delete (current_class_stack[current_class_depth].names_used);
5518 }
5519
5520 /* Mark the top of the class stack as hidden.  */
5521
5522 void
5523 push_class_stack (void)
5524 {
5525   if (current_class_depth)
5526     ++current_class_stack[current_class_depth - 1].hidden;
5527 }
5528
5529 /* Mark the top of the class stack as un-hidden.  */
5530
5531 void
5532 pop_class_stack (void)
5533 {
5534   if (current_class_depth)
5535     --current_class_stack[current_class_depth - 1].hidden;
5536 }
5537
5538 /* Returns 1 if the class type currently being defined is either T or
5539    a nested type of T.  */
5540
5541 bool
5542 currently_open_class (tree t)
5543 {
5544   int i;
5545
5546   /* We start looking from 1 because entry 0 is from global scope,
5547      and has no type.  */
5548   for (i = current_class_depth; i > 0; --i)
5549     {
5550       tree c;
5551       if (i == current_class_depth)
5552         c = current_class_type;
5553       else
5554         {
5555           if (current_class_stack[i].hidden)
5556             break;
5557           c = current_class_stack[i].type;
5558         }
5559       if (!c)
5560         continue;
5561       if (same_type_p (c, t))
5562         return true;
5563     }
5564   return false;
5565 }
5566
5567 /* If either current_class_type or one of its enclosing classes are derived
5568    from T, return the appropriate type.  Used to determine how we found
5569    something via unqualified lookup.  */
5570
5571 tree
5572 currently_open_derived_class (tree t)
5573 {
5574   int i;
5575
5576   /* The bases of a dependent type are unknown.  */
5577   if (dependent_type_p (t))
5578     return NULL_TREE;
5579
5580   if (!current_class_type)
5581     return NULL_TREE;
5582
5583   if (DERIVED_FROM_P (t, current_class_type))
5584     return current_class_type;
5585
5586   for (i = current_class_depth - 1; i > 0; --i)
5587     {
5588       if (current_class_stack[i].hidden)
5589         break;
5590       if (DERIVED_FROM_P (t, current_class_stack[i].type))
5591         return current_class_stack[i].type;
5592     }
5593
5594   return NULL_TREE;
5595 }
5596
5597 /* When entering a class scope, all enclosing class scopes' names with
5598    static meaning (static variables, static functions, types and
5599    enumerators) have to be visible.  This recursive function calls
5600    pushclass for all enclosing class contexts until global or a local
5601    scope is reached.  TYPE is the enclosed class.  */
5602
5603 void
5604 push_nested_class (tree type)
5605 {
5606   tree context;
5607
5608   /* A namespace might be passed in error cases, like A::B:C.  */
5609   if (type == NULL_TREE
5610       || type == error_mark_node
5611       || TREE_CODE (type) == NAMESPACE_DECL
5612       || ! IS_AGGR_TYPE (type)
5613       || TREE_CODE (type) == TEMPLATE_TYPE_PARM
5614       || TREE_CODE (type) == BOUND_TEMPLATE_TEMPLATE_PARM)
5615     return;
5616
5617   context = DECL_CONTEXT (TYPE_MAIN_DECL (type));
5618
5619   if (context && CLASS_TYPE_P (context))
5620     push_nested_class (context);
5621   pushclass (type);
5622 }
5623
5624 /* Undoes a push_nested_class call.  */
5625
5626 void
5627 pop_nested_class (void)
5628 {
5629   tree context = DECL_CONTEXT (TYPE_MAIN_DECL (current_class_type));
5630
5631   popclass ();
5632   if (context && CLASS_TYPE_P (context))
5633     pop_nested_class ();
5634 }
5635
5636 /* Returns the number of extern "LANG" blocks we are nested within.  */
5637
5638 int
5639 current_lang_depth (void)
5640 {
5641   return VEC_length (tree, current_lang_base);
5642 }
5643
5644 /* Set global variables CURRENT_LANG_NAME to appropriate value
5645    so that behavior of name-mangling machinery is correct.  */
5646
5647 void
5648 push_lang_context (tree name)
5649 {
5650   VEC_safe_push (tree, gc, current_lang_base, current_lang_name);
5651
5652   if (name == lang_name_cplusplus)
5653     {
5654       current_lang_name = name;
5655     }
5656   else if (name == lang_name_java)
5657     {
5658       current_lang_name = name;
5659       /* DECL_IGNORED_P is initially set for these types, to avoid clutter.
5660          (See record_builtin_java_type in decl.c.)  However, that causes
5661          incorrect debug entries if these types are actually used.
5662          So we re-enable debug output after extern "Java".  */
5663       DECL_IGNORED_P (TYPE_NAME (java_byte_type_node)) = 0;
5664       DECL_IGNORED_P (TYPE_NAME (java_short_type_node)) = 0;
5665       DECL_IGNORED_P (TYPE_NAME (java_int_type_node)) = 0;
5666       DECL_IGNORED_P (TYPE_NAME (java_long_type_node)) = 0;
5667       DECL_IGNORED_P (TYPE_NAME (java_float_type_node)) = 0;
5668       DECL_IGNORED_P (TYPE_NAME (java_double_type_node)) = 0;
5669       DECL_IGNORED_P (TYPE_NAME (java_char_type_node)) = 0;
5670       DECL_IGNORED_P (TYPE_NAME (java_boolean_type_node)) = 0;
5671     }
5672   else if (name == lang_name_c)
5673     {
5674       current_lang_name = name;
5675     }
5676   else
5677     error ("language string %<\"%E\"%> not recognized", name);
5678 }
5679
5680 /* Get out of the current language scope.  */
5681
5682 void
5683 pop_lang_context (void)
5684 {
5685   current_lang_name = VEC_pop (tree, current_lang_base);
5686 }
5687 \f
5688 /* Type instantiation routines.  */
5689
5690 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
5691    matches the TARGET_TYPE.  If there is no satisfactory match, return
5692    error_mark_node, and issue an error & warning messages under
5693    control of FLAGS.  Permit pointers to member function if FLAGS
5694    permits.  If TEMPLATE_ONLY, the name of the overloaded function was
5695    a template-id, and EXPLICIT_TARGS are the explicitly provided
5696    template arguments.  If OVERLOAD is for one or more member
5697    functions, then ACCESS_PATH is the base path used to reference
5698    those member functions.  */
5699
5700 static tree
5701 resolve_address_of_overloaded_function (tree target_type,
5702                                         tree overload,
5703                                         tsubst_flags_t flags,
5704                                         bool template_only,
5705                                         tree explicit_targs,
5706                                         tree access_path)
5707 {
5708   /* Here's what the standard says:
5709
5710        [over.over]
5711
5712        If the name is a function template, template argument deduction
5713        is done, and if the argument deduction succeeds, the deduced
5714        arguments are used to generate a single template function, which
5715        is added to the set of overloaded functions considered.
5716
5717        Non-member functions and static member functions match targets of
5718        type "pointer-to-function" or "reference-to-function."  Nonstatic
5719        member functions match targets of type "pointer-to-member
5720        function;" the function type of the pointer to member is used to
5721        select the member function from the set of overloaded member
5722        functions.  If a nonstatic member function is selected, the
5723        reference to the overloaded function name is required to have the
5724        form of a pointer to member as described in 5.3.1.
5725
5726        If more than one function is selected, any template functions in
5727        the set are eliminated if the set also contains a non-template
5728        function, and any given template function is eliminated if the
5729        set contains a second template function that is more specialized
5730        than the first according to the partial ordering rules 14.5.5.2.
5731        After such eliminations, if any, there shall remain exactly one
5732        selected function.  */
5733
5734   int is_ptrmem = 0;
5735   int is_reference = 0;
5736   /* We store the matches in a TREE_LIST rooted here.  The functions
5737      are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
5738      interoperability with most_specialized_instantiation.  */
5739   tree matches = NULL_TREE;
5740   tree fn;
5741
5742   /* By the time we get here, we should be seeing only real
5743      pointer-to-member types, not the internal POINTER_TYPE to
5744      METHOD_TYPE representation.  */
5745   gcc_assert (TREE_CODE (target_type) != POINTER_TYPE
5746               || TREE_CODE (TREE_TYPE (target_type)) != METHOD_TYPE);
5747
5748   gcc_assert (is_overloaded_fn (overload));
5749
5750   /* Check that the TARGET_TYPE is reasonable.  */
5751   if (TYPE_PTRFN_P (target_type))
5752     /* This is OK.  */;
5753   else if (TYPE_PTRMEMFUNC_P (target_type))
5754     /* This is OK, too.  */
5755     is_ptrmem = 1;
5756   else if (TREE_CODE (target_type) == FUNCTION_TYPE)
5757     {
5758       /* This is OK, too.  This comes from a conversion to reference
5759          type.  */
5760       target_type = build_reference_type (target_type);
5761       is_reference = 1;
5762     }
5763   else
5764     {
5765       if (flags & tf_error)
5766         error ("cannot resolve overloaded function %qD based on"
5767                " conversion to type %qT",
5768                DECL_NAME (OVL_FUNCTION (overload)), target_type);
5769       return error_mark_node;
5770     }
5771
5772   /* If we can find a non-template function that matches, we can just
5773      use it.  There's no point in generating template instantiations
5774      if we're just going to throw them out anyhow.  But, of course, we
5775      can only do this when we don't *need* a template function.  */
5776   if (!template_only)
5777     {
5778       tree fns;
5779
5780       for (fns = overload; fns; fns = OVL_NEXT (fns))
5781         {
5782           tree fn = OVL_CURRENT (fns);
5783           tree fntype;
5784
5785           if (TREE_CODE (fn) == TEMPLATE_DECL)
5786             /* We're not looking for templates just yet.  */
5787             continue;
5788
5789           if ((TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
5790               != is_ptrmem)
5791             /* We're looking for a non-static member, and this isn't
5792                one, or vice versa.  */
5793             continue;
5794
5795           /* Ignore functions which haven't been explicitly
5796              declared.  */
5797           if (DECL_ANTICIPATED (fn))
5798             continue;
5799
5800           /* See if there's a match.  */
5801           fntype = TREE_TYPE (fn);
5802           if (is_ptrmem)
5803             fntype = build_ptrmemfunc_type (build_pointer_type (fntype));
5804           else if (!is_reference)
5805             fntype = build_pointer_type (fntype);
5806
5807           if (can_convert_arg (target_type, fntype, fn, LOOKUP_NORMAL))
5808             matches = tree_cons (fn, NULL_TREE, matches);
5809         }
5810     }
5811
5812   /* Now, if we've already got a match (or matches), there's no need
5813      to proceed to the template functions.  But, if we don't have a
5814      match we need to look at them, too.  */
5815   if (!matches)
5816     {
5817       tree target_fn_type;
5818       tree target_arg_types;
5819       tree target_ret_type;
5820       tree fns;
5821
5822       if (is_ptrmem)
5823         target_fn_type
5824           = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (target_type));
5825       else
5826         target_fn_type = TREE_TYPE (target_type);
5827       target_arg_types = TYPE_ARG_TYPES (target_fn_type);
5828       target_ret_type = TREE_TYPE (target_fn_type);
5829
5830       /* Never do unification on the 'this' parameter.  */
5831       if (TREE_CODE (target_fn_type) == METHOD_TYPE)
5832         target_arg_types = TREE_CHAIN (target_arg_types);
5833
5834       for (fns = overload; fns; fns = OVL_NEXT (fns))
5835         {
5836           tree fn = OVL_CURRENT (fns);
5837           tree instantiation;
5838           tree instantiation_type;
5839           tree targs;
5840
5841           if (TREE_CODE (fn) != TEMPLATE_DECL)
5842             /* We're only looking for templates.  */
5843             continue;
5844
5845           if ((TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
5846               != is_ptrmem)
5847             /* We're not looking for a non-static member, and this is
5848                one, or vice versa.  */
5849             continue;
5850
5851           /* Try to do argument deduction.  */
5852           targs = make_tree_vec (DECL_NTPARMS (fn));
5853           if (fn_type_unification (fn, explicit_targs, targs,
5854                                    target_arg_types, target_ret_type,
5855                                    DEDUCE_EXACT, LOOKUP_NORMAL))
5856             /* Argument deduction failed.  */
5857             continue;
5858
5859           /* Instantiate the template.  */
5860           instantiation = instantiate_template (fn, targs, flags);
5861           if (instantiation == error_mark_node)
5862             /* Instantiation failed.  */
5863             continue;
5864
5865           /* See if there's a match.  */
5866           instantiation_type = TREE_TYPE (instantiation);
5867           if (is_ptrmem)
5868             instantiation_type =
5869               build_ptrmemfunc_type (build_pointer_type (instantiation_type));
5870           else if (!is_reference)
5871             instantiation_type = build_pointer_type (instantiation_type);
5872           if (can_convert_arg (target_type, instantiation_type, instantiation,
5873                                LOOKUP_NORMAL))
5874             matches = tree_cons (instantiation, fn, matches);
5875         }
5876
5877       /* Now, remove all but the most specialized of the matches.  */
5878       if (matches)
5879         {
5880           tree match = most_specialized_instantiation (matches);
5881
5882           if (match != error_mark_node)
5883             matches = tree_cons (TREE_PURPOSE (match),
5884                                  NULL_TREE,
5885                                  NULL_TREE);
5886         }
5887     }
5888
5889   /* Now we should have exactly one function in MATCHES.  */
5890   if (matches == NULL_TREE)
5891     {
5892       /* There were *no* matches.  */
5893       if (flags & tf_error)
5894         {
5895           error ("no matches converting function %qD to type %q#T",
5896                  DECL_NAME (OVL_FUNCTION (overload)),
5897                  target_type);
5898
5899           /* print_candidates expects a chain with the functions in
5900              TREE_VALUE slots, so we cons one up here (we're losing anyway,
5901              so why be clever?).  */
5902           for (; overload; overload = OVL_NEXT (overload))
5903             matches = tree_cons (NULL_TREE, OVL_CURRENT (overload),
5904                                  matches);
5905
5906           print_candidates (matches);
5907         }
5908       return error_mark_node;
5909     }
5910   else if (TREE_CHAIN (matches))
5911     {
5912       /* There were too many matches.  */
5913
5914       if (flags & tf_error)
5915         {
5916           tree match;
5917
5918           error ("converting overloaded function %qD to type %q#T is ambiguous",
5919                     DECL_NAME (OVL_FUNCTION (overload)),
5920                     target_type);
5921
5922           /* Since print_candidates expects the functions in the
5923              TREE_VALUE slot, we flip them here.  */
5924           for (match = matches; match; match = TREE_CHAIN (match))
5925             TREE_VALUE (match) = TREE_PURPOSE (match);
5926
5927           print_candidates (matches);
5928         }
5929
5930       return error_mark_node;
5931     }
5932
5933   /* Good, exactly one match.  Now, convert it to the correct type.  */
5934   fn = TREE_PURPOSE (matches);
5935
5936   if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)
5937       && !(flags & tf_ptrmem_ok) && !flag_ms_extensions)
5938     {
5939       static int explained;
5940
5941       if (!(flags & tf_error))
5942         return error_mark_node;
5943
5944       pedwarn ("assuming pointer to member %qD", fn);
5945       if (!explained)
5946         {
5947           pedwarn ("(a pointer to member can only be formed with %<&%E%>)", fn);
5948           explained = 1;
5949         }
5950     }
5951
5952   /* If we're doing overload resolution purely for the purpose of
5953      determining conversion sequences, we should not consider the
5954      function used.  If this conversion sequence is selected, the
5955      function will be marked as used at this point.  */
5956   if (!(flags & tf_conv))
5957     {
5958       mark_used (fn);
5959       /* We could not check access when this expression was originally
5960          created since we did not know at that time to which function
5961          the expression referred.  */
5962       if (DECL_FUNCTION_MEMBER_P (fn))
5963         {
5964           gcc_assert (access_path);
5965           perform_or_defer_access_check (access_path, fn, fn);
5966         }
5967     }
5968
5969   if (TYPE_PTRFN_P (target_type) || TYPE_PTRMEMFUNC_P (target_type))
5970     return build_unary_op (ADDR_EXPR, fn, 0);
5971   else
5972     {
5973       /* The target must be a REFERENCE_TYPE.  Above, build_unary_op
5974          will mark the function as addressed, but here we must do it
5975          explicitly.  */
5976       cxx_mark_addressable (fn);
5977
5978       return fn;
5979     }
5980 }
5981
5982 /* This function will instantiate the type of the expression given in
5983    RHS to match the type of LHSTYPE.  If errors exist, then return
5984    error_mark_node. FLAGS is a bit mask.  If TF_ERROR is set, then
5985    we complain on errors.  If we are not complaining, never modify rhs,
5986    as overload resolution wants to try many possible instantiations, in
5987    the hope that at least one will work.
5988
5989    For non-recursive calls, LHSTYPE should be a function, pointer to
5990    function, or a pointer to member function.  */
5991
5992 tree
5993 instantiate_type (tree lhstype, tree rhs, tsubst_flags_t flags)
5994 {
5995   tsubst_flags_t flags_in = flags;
5996   tree access_path = NULL_TREE;
5997
5998   flags &= ~tf_ptrmem_ok;
5999
6000   if (TREE_CODE (lhstype) == UNKNOWN_TYPE)
6001     {
6002       if (flags & tf_error)
6003         error ("not enough type information");
6004       return error_mark_node;
6005     }
6006
6007   if (TREE_TYPE (rhs) != NULL_TREE && ! (type_unknown_p (rhs)))
6008     {
6009       if (same_type_p (lhstype, TREE_TYPE (rhs)))
6010         return rhs;
6011       if (flag_ms_extensions
6012           && TYPE_PTRMEMFUNC_P (lhstype)
6013           && !TYPE_PTRMEMFUNC_P (TREE_TYPE (rhs)))
6014         /* Microsoft allows `A::f' to be resolved to a
6015            pointer-to-member.  */
6016         ;
6017       else
6018         {
6019           if (flags & tf_error)
6020             error ("argument of type %qT does not match %qT",
6021                    TREE_TYPE (rhs), lhstype);
6022           return error_mark_node;
6023         }
6024     }
6025
6026   if (TREE_CODE (rhs) == BASELINK)
6027     {
6028       access_path = BASELINK_ACCESS_BINFO (rhs);
6029       rhs = BASELINK_FUNCTIONS (rhs);
6030     }
6031
6032   /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
6033      deduce any type information.  */
6034   if (TREE_CODE (rhs) == NON_DEPENDENT_EXPR)
6035     {
6036       if (flags & tf_error)
6037         error ("not enough type information");
6038       return error_mark_node;
6039     }
6040
6041   /* There only a few kinds of expressions that may have a type
6042      dependent on overload resolution.  */
6043   gcc_assert (TREE_CODE (rhs) == ADDR_EXPR
6044               || TREE_CODE (rhs) == COMPONENT_REF
6045               || TREE_CODE (rhs) == COMPOUND_EXPR
6046               || really_overloaded_fn (rhs));
6047
6048   /* We don't overwrite rhs if it is an overloaded function.
6049      Copying it would destroy the tree link.  */
6050   if (TREE_CODE (rhs) != OVERLOAD)
6051     rhs = copy_node (rhs);
6052
6053   /* This should really only be used when attempting to distinguish
6054      what sort of a pointer to function we have.  For now, any
6055      arithmetic operation which is not supported on pointers
6056      is rejected as an error.  */
6057
6058   switch (TREE_CODE (rhs))
6059     {
6060     case COMPONENT_REF:
6061       {
6062         tree member = TREE_OPERAND (rhs, 1);
6063
6064         member = instantiate_type (lhstype, member, flags);
6065         if (member != error_mark_node
6066             && TREE_SIDE_EFFECTS (TREE_OPERAND (rhs, 0)))
6067           /* Do not lose object's side effects.  */
6068           return build2 (COMPOUND_EXPR, TREE_TYPE (member),
6069                          TREE_OPERAND (rhs, 0), member);
6070         return member;
6071       }
6072
6073     case OFFSET_REF:
6074       rhs = TREE_OPERAND (rhs, 1);
6075       if (BASELINK_P (rhs))
6076         return instantiate_type (lhstype, rhs, flags_in);
6077
6078       /* This can happen if we are forming a pointer-to-member for a
6079          member template.  */
6080       gcc_assert (TREE_CODE (rhs) == TEMPLATE_ID_EXPR);
6081
6082       /* Fall through.  */
6083
6084     case TEMPLATE_ID_EXPR:
6085       {
6086         tree fns = TREE_OPERAND (rhs, 0);
6087         tree args = TREE_OPERAND (rhs, 1);
6088
6089         return
6090           resolve_address_of_overloaded_function (lhstype, fns, flags_in,
6091                                                   /*template_only=*/true,
6092                                                   args, access_path);
6093       }
6094
6095     case OVERLOAD:
6096     case FUNCTION_DECL:
6097       return
6098         resolve_address_of_overloaded_function (lhstype, rhs, flags_in,
6099                                                 /*template_only=*/false,
6100                                                 /*explicit_targs=*/NULL_TREE,
6101                                                 access_path);
6102
6103     case COMPOUND_EXPR:
6104       TREE_OPERAND (rhs, 0)
6105         = instantiate_type (lhstype, TREE_OPERAND (rhs, 0), flags);
6106       if (TREE_OPERAND (rhs, 0) == error_mark_node)
6107         return error_mark_node;
6108       TREE_OPERAND (rhs, 1)
6109         = instantiate_type (lhstype, TREE_OPERAND (rhs, 1), flags);
6110       if (TREE_OPERAND (rhs, 1) == error_mark_node)
6111         return error_mark_node;
6112
6113       TREE_TYPE (rhs) = lhstype;
6114       return rhs;
6115
6116     case ADDR_EXPR:
6117     {
6118       if (PTRMEM_OK_P (rhs))
6119         flags |= tf_ptrmem_ok;
6120
6121       return instantiate_type (lhstype, TREE_OPERAND (rhs, 0), flags);
6122     }
6123
6124     case ERROR_MARK:
6125       return error_mark_node;
6126
6127     default:
6128       gcc_unreachable ();
6129     }
6130   return error_mark_node;
6131 }
6132 \f
6133 /* Return the name of the virtual function pointer field
6134    (as an IDENTIFIER_NODE) for the given TYPE.  Note that
6135    this may have to look back through base types to find the
6136    ultimate field name.  (For single inheritance, these could
6137    all be the same name.  Who knows for multiple inheritance).  */
6138
6139 static tree
6140 get_vfield_name (tree type)
6141 {
6142   tree binfo, base_binfo;
6143   char *buf;
6144
6145   for (binfo = TYPE_BINFO (type);
6146        BINFO_N_BASE_BINFOS (binfo);
6147        binfo = base_binfo)
6148     {
6149       base_binfo = BINFO_BASE_BINFO (binfo, 0);
6150
6151       if (BINFO_VIRTUAL_P (base_binfo)
6152           || !TYPE_CONTAINS_VPTR_P (BINFO_TYPE (base_binfo)))
6153         break;
6154     }
6155
6156   type = BINFO_TYPE (binfo);
6157   buf = (char *) alloca (sizeof (VFIELD_NAME_FORMAT)
6158                          + TYPE_NAME_LENGTH (type) + 2);
6159   sprintf (buf, VFIELD_NAME_FORMAT,
6160            IDENTIFIER_POINTER (constructor_name (type)));
6161   return get_identifier (buf);
6162 }
6163
6164 void
6165 print_class_statistics (void)
6166 {
6167 #ifdef GATHER_STATISTICS
6168   fprintf (stderr, "convert_harshness = %d\n", n_convert_harshness);
6169   fprintf (stderr, "compute_conversion_costs = %d\n", n_compute_conversion_costs);
6170   if (n_vtables)
6171     {
6172       fprintf (stderr, "vtables = %d; vtable searches = %d\n",
6173                n_vtables, n_vtable_searches);
6174       fprintf (stderr, "vtable entries = %d; vtable elems = %d\n",
6175                n_vtable_entries, n_vtable_elems);
6176     }
6177 #endif
6178 }
6179
6180 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
6181    according to [class]:
6182                                           The class-name is also inserted
6183    into  the scope of the class itself.  For purposes of access checking,
6184    the inserted class name is treated as if it were a public member name.  */
6185
6186 void
6187 build_self_reference (void)
6188 {
6189   tree name = constructor_name (current_class_type);
6190   tree value = build_lang_decl (TYPE_DECL, name, current_class_type);
6191   tree saved_cas;
6192
6193   DECL_NONLOCAL (value) = 1;
6194   DECL_CONTEXT (value) = current_class_type;
6195   DECL_ARTIFICIAL (value) = 1;
6196   SET_DECL_SELF_REFERENCE_P (value);
6197
6198   if (processing_template_decl)
6199     value = push_template_decl (value);
6200
6201   saved_cas = current_access_specifier;
6202   current_access_specifier = access_public_node;
6203   finish_member_declaration (value);
6204   current_access_specifier = saved_cas;
6205 }
6206
6207 /* Returns 1 if TYPE contains only padding bytes.  */
6208
6209 int
6210 is_empty_class (tree type)
6211 {
6212   if (type == error_mark_node)
6213     return 0;
6214
6215   if (! IS_AGGR_TYPE (type))
6216     return 0;
6217
6218   /* In G++ 3.2, whether or not a class was empty was determined by
6219      looking at its size.  */
6220   if (abi_version_at_least (2))
6221     return CLASSTYPE_EMPTY_P (type);
6222   else
6223     return integer_zerop (CLASSTYPE_SIZE (type));
6224 }
6225
6226 /* Returns true if TYPE contains an empty class.  */
6227
6228 static bool
6229 contains_empty_class_p (tree type)
6230 {
6231   if (is_empty_class (type))
6232     return true;
6233   if (CLASS_TYPE_P (type))
6234     {
6235       tree field;
6236       tree binfo;
6237       tree base_binfo;
6238       int i;
6239
6240       for (binfo = TYPE_BINFO (type), i = 0;
6241            BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
6242         if (contains_empty_class_p (BINFO_TYPE (base_binfo)))
6243           return true;
6244       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
6245         if (TREE_CODE (field) == FIELD_DECL
6246             && !DECL_ARTIFICIAL (field)
6247             && is_empty_class (TREE_TYPE (field)))
6248           return true;
6249     }
6250   else if (TREE_CODE (type) == ARRAY_TYPE)
6251     return contains_empty_class_p (TREE_TYPE (type));
6252   return false;
6253 }
6254
6255 /* Note that NAME was looked up while the current class was being
6256    defined and that the result of that lookup was DECL.  */
6257
6258 void
6259 maybe_note_name_used_in_class (tree name, tree decl)
6260 {
6261   splay_tree names_used;
6262
6263   /* If we're not defining a class, there's nothing to do.  */
6264   if (!(innermost_scope_kind() == sk_class
6265         && TYPE_BEING_DEFINED (current_class_type)))
6266     return;
6267
6268   /* If there's already a binding for this NAME, then we don't have
6269      anything to worry about.  */
6270   if (lookup_member (current_class_type, name,
6271                      /*protect=*/0, /*want_type=*/false))
6272     return;
6273
6274   if (!current_class_stack[current_class_depth - 1].names_used)
6275     current_class_stack[current_class_depth - 1].names_used
6276       = splay_tree_new (splay_tree_compare_pointers, 0, 0);
6277   names_used = current_class_stack[current_class_depth - 1].names_used;
6278
6279   splay_tree_insert (names_used,
6280                      (splay_tree_key) name,
6281                      (splay_tree_value) decl);
6282 }
6283
6284 /* Note that NAME was declared (as DECL) in the current class.  Check
6285    to see that the declaration is valid.  */
6286
6287 void
6288 note_name_declared_in_class (tree name, tree decl)
6289 {
6290   splay_tree names_used;
6291   splay_tree_node n;
6292
6293   /* Look to see if we ever used this name.  */
6294   names_used
6295     = current_class_stack[current_class_depth - 1].names_used;
6296   if (!names_used)
6297     return;
6298
6299   n = splay_tree_lookup (names_used, (splay_tree_key) name);
6300   if (n)
6301     {
6302       /* [basic.scope.class]
6303
6304          A name N used in a class S shall refer to the same declaration
6305          in its context and when re-evaluated in the completed scope of
6306          S.  */
6307       pedwarn ("declaration of %q#D", decl);
6308       pedwarn ("changes meaning of %qD from %q+#D",
6309                DECL_NAME (OVL_CURRENT (decl)), (tree) n->value);
6310     }
6311 }
6312
6313 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
6314    Secondary vtables are merged with primary vtables; this function
6315    will return the VAR_DECL for the primary vtable.  */
6316
6317 tree
6318 get_vtbl_decl_for_binfo (tree binfo)
6319 {
6320   tree decl;
6321
6322   decl = BINFO_VTABLE (binfo);
6323   if (decl && TREE_CODE (decl) == PLUS_EXPR)
6324     {
6325       gcc_assert (TREE_CODE (TREE_OPERAND (decl, 0)) == ADDR_EXPR);
6326       decl = TREE_OPERAND (TREE_OPERAND (decl, 0), 0);
6327     }
6328   if (decl)
6329     gcc_assert (TREE_CODE (decl) == VAR_DECL);
6330   return decl;
6331 }
6332
6333
6334 /* Returns the binfo for the primary base of BINFO.  If the resulting
6335    BINFO is a virtual base, and it is inherited elsewhere in the
6336    hierarchy, then the returned binfo might not be the primary base of
6337    BINFO in the complete object.  Check BINFO_PRIMARY_P or
6338    BINFO_LOST_PRIMARY_P to be sure.  */
6339
6340 static tree
6341 get_primary_binfo (tree binfo)
6342 {
6343   tree primary_base;
6344
6345   primary_base = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (binfo));
6346   if (!primary_base)
6347     return NULL_TREE;
6348
6349   return copied_binfo (primary_base, binfo);
6350 }
6351
6352 /* If INDENTED_P is zero, indent to INDENT. Return nonzero.  */
6353
6354 static int
6355 maybe_indent_hierarchy (FILE * stream, int indent, int indented_p)
6356 {
6357   if (!indented_p)
6358     fprintf (stream, "%*s", indent, "");
6359   return 1;
6360 }
6361
6362 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
6363    INDENT should be zero when called from the top level; it is
6364    incremented recursively.  IGO indicates the next expected BINFO in
6365    inheritance graph ordering.  */
6366
6367 static tree
6368 dump_class_hierarchy_r (FILE *stream,
6369                         int flags,
6370                         tree binfo,
6371                         tree igo,
6372                         int indent)
6373 {
6374   int indented = 0;
6375   tree base_binfo;
6376   int i;
6377
6378   indented = maybe_indent_hierarchy (stream, indent, 0);
6379   fprintf (stream, "%s (0x%lx) ",
6380            type_as_string (BINFO_TYPE (binfo), TFF_PLAIN_IDENTIFIER),
6381            (unsigned long) binfo);
6382   if (binfo != igo)
6383     {
6384       fprintf (stream, "alternative-path\n");
6385       return igo;
6386     }
6387   igo = TREE_CHAIN (binfo);
6388
6389   fprintf (stream, HOST_WIDE_INT_PRINT_DEC,
6390            tree_low_cst (BINFO_OFFSET (binfo), 0));
6391   if (is_empty_class (BINFO_TYPE (binfo)))
6392     fprintf (stream, " empty");
6393   else if (CLASSTYPE_NEARLY_EMPTY_P (BINFO_TYPE (binfo)))
6394     fprintf (stream, " nearly-empty");
6395   if (BINFO_VIRTUAL_P (binfo))
6396     fprintf (stream, " virtual");
6397   fprintf (stream, "\n");
6398
6399   indented = 0;
6400   if (BINFO_PRIMARY_P (binfo))
6401     {
6402       indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6403       fprintf (stream, " primary-for %s (0x%lx)",
6404                type_as_string (BINFO_TYPE (BINFO_INHERITANCE_CHAIN (binfo)),
6405                                TFF_PLAIN_IDENTIFIER),
6406                (unsigned long)BINFO_INHERITANCE_CHAIN (binfo));
6407     }
6408   if (BINFO_LOST_PRIMARY_P (binfo))
6409     {
6410       indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6411       fprintf (stream, " lost-primary");
6412     }
6413   if (indented)
6414     fprintf (stream, "\n");
6415
6416   if (!(flags & TDF_SLIM))
6417     {
6418       int indented = 0;
6419
6420       if (BINFO_SUBVTT_INDEX (binfo))
6421         {
6422           indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6423           fprintf (stream, " subvttidx=%s",
6424                    expr_as_string (BINFO_SUBVTT_INDEX (binfo),
6425                                    TFF_PLAIN_IDENTIFIER));
6426         }
6427       if (BINFO_VPTR_INDEX (binfo))
6428         {
6429           indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6430           fprintf (stream, " vptridx=%s",
6431                    expr_as_string (BINFO_VPTR_INDEX (binfo),
6432                                    TFF_PLAIN_IDENTIFIER));
6433         }
6434       if (BINFO_VPTR_FIELD (binfo))
6435         {
6436           indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6437           fprintf (stream, " vbaseoffset=%s",
6438                    expr_as_string (BINFO_VPTR_FIELD (binfo),
6439                                    TFF_PLAIN_IDENTIFIER));
6440         }
6441       if (BINFO_VTABLE (binfo))
6442         {
6443           indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6444           fprintf (stream, " vptr=%s",
6445                    expr_as_string (BINFO_VTABLE (binfo),
6446                                    TFF_PLAIN_IDENTIFIER));
6447         }
6448
6449       if (indented)
6450         fprintf (stream, "\n");
6451     }
6452
6453   for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
6454     igo = dump_class_hierarchy_r (stream, flags, base_binfo, igo, indent + 2);
6455
6456   return igo;
6457 }
6458
6459 /* Dump the BINFO hierarchy for T.  */
6460
6461 static void
6462 dump_class_hierarchy_1 (FILE *stream, int flags, tree t)
6463 {
6464   fprintf (stream, "Class %s\n", type_as_string (t, TFF_PLAIN_IDENTIFIER));
6465   fprintf (stream, "   size=%lu align=%lu\n",
6466            (unsigned long)(tree_low_cst (TYPE_SIZE (t), 0) / BITS_PER_UNIT),
6467            (unsigned long)(TYPE_ALIGN (t) / BITS_PER_UNIT));
6468   fprintf (stream, "   base size=%lu base align=%lu\n",
6469            (unsigned long)(tree_low_cst (TYPE_SIZE (CLASSTYPE_AS_BASE (t)), 0)
6470                            / BITS_PER_UNIT),
6471            (unsigned long)(TYPE_ALIGN (CLASSTYPE_AS_BASE (t))
6472                            / BITS_PER_UNIT));
6473   dump_class_hierarchy_r (stream, flags, TYPE_BINFO (t), TYPE_BINFO (t), 0);
6474   fprintf (stream, "\n");
6475 }
6476
6477 /* Debug interface to hierarchy dumping.  */
6478
6479 void
6480 debug_class (tree t)
6481 {
6482   dump_class_hierarchy_1 (stderr, TDF_SLIM, t);
6483 }
6484
6485 static void
6486 dump_class_hierarchy (tree t)
6487 {
6488   int flags;
6489   FILE *stream = dump_begin (TDI_class, &flags);
6490
6491   if (stream)
6492     {
6493       dump_class_hierarchy_1 (stream, flags, t);
6494       dump_end (TDI_class, stream);
6495     }
6496 }
6497
6498 static void
6499 dump_array (FILE * stream, tree decl)
6500 {
6501   tree value;
6502   unsigned HOST_WIDE_INT ix;
6503   HOST_WIDE_INT elt;
6504   tree size = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (decl)));
6505
6506   elt = (tree_low_cst (TYPE_SIZE (TREE_TYPE (TREE_TYPE (decl))), 0)
6507          / BITS_PER_UNIT);
6508   fprintf (stream, "%s:", decl_as_string (decl, TFF_PLAIN_IDENTIFIER));
6509   fprintf (stream, " %s entries",
6510            expr_as_string (size_binop (PLUS_EXPR, size, size_one_node),
6511                            TFF_PLAIN_IDENTIFIER));
6512   fprintf (stream, "\n");
6513
6514   FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (DECL_INITIAL (decl)),
6515                               ix, value)
6516     fprintf (stream, "%-4ld  %s\n", (long)(ix * elt),
6517              expr_as_string (value, TFF_PLAIN_IDENTIFIER));
6518 }
6519
6520 static void
6521 dump_vtable (tree t, tree binfo, tree vtable)
6522 {
6523   int flags;
6524   FILE *stream = dump_begin (TDI_class, &flags);
6525
6526   if (!stream)
6527     return;
6528
6529   if (!(flags & TDF_SLIM))
6530     {
6531       int ctor_vtbl_p = TYPE_BINFO (t) != binfo;
6532
6533       fprintf (stream, "%s for %s",
6534                ctor_vtbl_p ? "Construction vtable" : "Vtable",
6535                type_as_string (BINFO_TYPE (binfo), TFF_PLAIN_IDENTIFIER));
6536       if (ctor_vtbl_p)
6537         {
6538           if (!BINFO_VIRTUAL_P (binfo))
6539             fprintf (stream, " (0x%lx instance)", (unsigned long)binfo);
6540           fprintf (stream, " in %s", type_as_string (t, TFF_PLAIN_IDENTIFIER));
6541         }
6542       fprintf (stream, "\n");
6543       dump_array (stream, vtable);
6544       fprintf (stream, "\n");
6545     }
6546
6547   dump_end (TDI_class, stream);
6548 }
6549
6550 static void
6551 dump_vtt (tree t, tree vtt)
6552 {
6553   int flags;
6554   FILE *stream = dump_begin (TDI_class, &flags);
6555
6556   if (!stream)
6557     return;
6558
6559   if (!(flags & TDF_SLIM))
6560     {
6561       fprintf (stream, "VTT for %s\n",
6562                type_as_string (t, TFF_PLAIN_IDENTIFIER));
6563       dump_array (stream, vtt);
6564       fprintf (stream, "\n");
6565     }
6566
6567   dump_end (TDI_class, stream);
6568 }
6569
6570 /* Dump a function or thunk and its thunkees.  */
6571
6572 static void
6573 dump_thunk (FILE *stream, int indent, tree thunk)
6574 {
6575   static const char spaces[] = "        ";
6576   tree name = DECL_NAME (thunk);
6577   tree thunks;
6578
6579   fprintf (stream, "%.*s%p %s %s", indent, spaces,
6580            (void *)thunk,
6581            !DECL_THUNK_P (thunk) ? "function"
6582            : DECL_THIS_THUNK_P (thunk) ? "this-thunk" : "covariant-thunk",
6583            name ? IDENTIFIER_POINTER (name) : "<unset>");
6584   if (DECL_THUNK_P (thunk))
6585     {
6586       HOST_WIDE_INT fixed_adjust = THUNK_FIXED_OFFSET (thunk);
6587       tree virtual_adjust = THUNK_VIRTUAL_OFFSET (thunk);
6588
6589       fprintf (stream, " fixed=" HOST_WIDE_INT_PRINT_DEC, fixed_adjust);
6590       if (!virtual_adjust)
6591         /*NOP*/;
6592       else if (DECL_THIS_THUNK_P (thunk))
6593         fprintf (stream, " vcall="  HOST_WIDE_INT_PRINT_DEC,
6594                  tree_low_cst (virtual_adjust, 0));
6595       else
6596         fprintf (stream, " vbase=" HOST_WIDE_INT_PRINT_DEC "(%s)",
6597                  tree_low_cst (BINFO_VPTR_FIELD (virtual_adjust), 0),
6598                  type_as_string (BINFO_TYPE (virtual_adjust), TFF_SCOPE));
6599       if (THUNK_ALIAS (thunk))
6600         fprintf (stream, " alias to %p", (void *)THUNK_ALIAS (thunk));
6601     }
6602   fprintf (stream, "\n");
6603   for (thunks = DECL_THUNKS (thunk); thunks; thunks = TREE_CHAIN (thunks))
6604     dump_thunk (stream, indent + 2, thunks);
6605 }
6606
6607 /* Dump the thunks for FN.  */
6608
6609 void
6610 debug_thunks (tree fn)
6611 {
6612   dump_thunk (stderr, 0, fn);
6613 }
6614
6615 /* Virtual function table initialization.  */
6616
6617 /* Create all the necessary vtables for T and its base classes.  */
6618
6619 static void
6620 finish_vtbls (tree t)
6621 {
6622   tree list;
6623   tree vbase;
6624
6625   /* We lay out the primary and secondary vtables in one contiguous
6626      vtable.  The primary vtable is first, followed by the non-virtual
6627      secondary vtables in inheritance graph order.  */
6628   list = build_tree_list (BINFO_VTABLE (TYPE_BINFO (t)), NULL_TREE);
6629   accumulate_vtbl_inits (TYPE_BINFO (t), TYPE_BINFO (t),
6630                          TYPE_BINFO (t), t, list);
6631
6632   /* Then come the virtual bases, also in inheritance graph order.  */
6633   for (vbase = TYPE_BINFO (t); vbase; vbase = TREE_CHAIN (vbase))
6634     {
6635       if (!BINFO_VIRTUAL_P (vbase))
6636         continue;
6637       accumulate_vtbl_inits (vbase, vbase, TYPE_BINFO (t), t, list);
6638     }
6639
6640   if (BINFO_VTABLE (TYPE_BINFO (t)))
6641     initialize_vtable (TYPE_BINFO (t), TREE_VALUE (list));
6642 }
6643
6644 /* Initialize the vtable for BINFO with the INITS.  */
6645
6646 static void
6647 initialize_vtable (tree binfo, tree inits)
6648 {
6649   tree decl;
6650
6651   layout_vtable_decl (binfo, list_length (inits));
6652   decl = get_vtbl_decl_for_binfo (binfo);
6653   initialize_artificial_var (decl, inits);
6654   dump_vtable (BINFO_TYPE (binfo), binfo, decl);
6655 }
6656
6657 /* Build the VTT (virtual table table) for T.
6658    A class requires a VTT if it has virtual bases.
6659
6660    This holds
6661    1 - primary virtual pointer for complete object T
6662    2 - secondary VTTs for each direct non-virtual base of T which requires a
6663        VTT
6664    3 - secondary virtual pointers for each direct or indirect base of T which
6665        has virtual bases or is reachable via a virtual path from T.
6666    4 - secondary VTTs for each direct or indirect virtual base of T.
6667
6668    Secondary VTTs look like complete object VTTs without part 4.  */
6669
6670 static void
6671 build_vtt (tree t)
6672 {
6673   tree inits;
6674   tree type;
6675   tree vtt;
6676   tree index;
6677
6678   /* Build up the initializers for the VTT.  */
6679   inits = NULL_TREE;
6680   index = size_zero_node;
6681   build_vtt_inits (TYPE_BINFO (t), t, &inits, &index);
6682
6683   /* If we didn't need a VTT, we're done.  */
6684   if (!inits)
6685     return;
6686
6687   /* Figure out the type of the VTT.  */
6688   type = build_index_type (size_int (list_length (inits) - 1));
6689   type = build_cplus_array_type (const_ptr_type_node, type);
6690
6691   /* Now, build the VTT object itself.  */
6692   vtt = build_vtable (t, mangle_vtt_for_type (t), type);
6693   initialize_artificial_var (vtt, inits);
6694   /* Add the VTT to the vtables list.  */
6695   TREE_CHAIN (vtt) = TREE_CHAIN (CLASSTYPE_VTABLES (t));
6696   TREE_CHAIN (CLASSTYPE_VTABLES (t)) = vtt;
6697
6698   dump_vtt (t, vtt);
6699 }
6700
6701 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
6702    PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
6703    and CHAIN the vtable pointer for this binfo after construction is
6704    complete.  VALUE can also be another BINFO, in which case we recurse.  */
6705
6706 static tree
6707 binfo_ctor_vtable (tree binfo)
6708 {
6709   tree vt;
6710
6711   while (1)
6712     {
6713       vt = BINFO_VTABLE (binfo);
6714       if (TREE_CODE (vt) == TREE_LIST)
6715         vt = TREE_VALUE (vt);
6716       if (TREE_CODE (vt) == TREE_BINFO)
6717         binfo = vt;
6718       else
6719         break;
6720     }
6721
6722   return vt;
6723 }
6724
6725 /* Data for secondary VTT initialization.  */
6726 typedef struct secondary_vptr_vtt_init_data_s
6727 {
6728   /* Is this the primary VTT? */
6729   bool top_level_p;
6730
6731   /* Current index into the VTT.  */
6732   tree index;
6733
6734   /* TREE_LIST of initializers built up.  */
6735   tree inits;
6736
6737   /* The type being constructed by this secondary VTT.  */
6738   tree type_being_constructed;
6739 } secondary_vptr_vtt_init_data;
6740
6741 /* Recursively build the VTT-initializer for BINFO (which is in the
6742    hierarchy dominated by T).  INITS points to the end of the initializer
6743    list to date.  INDEX is the VTT index where the next element will be
6744    replaced.  Iff BINFO is the binfo for T, this is the top level VTT (i.e.
6745    not a subvtt for some base of T).  When that is so, we emit the sub-VTTs
6746    for virtual bases of T. When it is not so, we build the constructor
6747    vtables for the BINFO-in-T variant.  */
6748
6749 static tree *
6750 build_vtt_inits (tree binfo, tree t, tree *inits, tree *index)
6751 {
6752   int i;
6753   tree b;
6754   tree init;
6755   tree secondary_vptrs;
6756   secondary_vptr_vtt_init_data data;
6757   int top_level_p = SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t);
6758
6759   /* We only need VTTs for subobjects with virtual bases.  */
6760   if (!CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo)))
6761     return inits;
6762
6763   /* We need to use a construction vtable if this is not the primary
6764      VTT.  */
6765   if (!top_level_p)
6766     {
6767       build_ctor_vtbl_group (binfo, t);
6768
6769       /* Record the offset in the VTT where this sub-VTT can be found.  */
6770       BINFO_SUBVTT_INDEX (binfo) = *index;
6771     }
6772
6773   /* Add the address of the primary vtable for the complete object.  */
6774   init = binfo_ctor_vtable (binfo);
6775   *inits = build_tree_list (NULL_TREE, init);
6776   inits = &TREE_CHAIN (*inits);
6777   if (top_level_p)
6778     {
6779       gcc_assert (!BINFO_VPTR_INDEX (binfo));
6780       BINFO_VPTR_INDEX (binfo) = *index;
6781     }
6782   *index = size_binop (PLUS_EXPR, *index, TYPE_SIZE_UNIT (ptr_type_node));
6783
6784   /* Recursively add the secondary VTTs for non-virtual bases.  */
6785   for (i = 0; BINFO_BASE_ITERATE (binfo, i, b); ++i)
6786     if (!BINFO_VIRTUAL_P (b))
6787       inits = build_vtt_inits (b, t, inits, index);
6788
6789   /* Add secondary virtual pointers for all subobjects of BINFO with
6790      either virtual bases or reachable along a virtual path, except
6791      subobjects that are non-virtual primary bases.  */
6792   data.top_level_p = top_level_p;
6793   data.index = *index;
6794   data.inits = NULL;
6795   data.type_being_constructed = BINFO_TYPE (binfo);
6796
6797   dfs_walk_once (binfo, dfs_build_secondary_vptr_vtt_inits, NULL, &data);
6798
6799   *index = data.index;
6800
6801   /* The secondary vptrs come back in reverse order.  After we reverse
6802      them, and add the INITS, the last init will be the first element
6803      of the chain.  */
6804   secondary_vptrs = data.inits;
6805   if (secondary_vptrs)
6806     {
6807       *inits = nreverse (secondary_vptrs);
6808       inits = &TREE_CHAIN (secondary_vptrs);
6809       gcc_assert (*inits == NULL_TREE);
6810     }
6811
6812   if (top_level_p)
6813     /* Add the secondary VTTs for virtual bases in inheritance graph
6814        order.  */
6815     for (b = TYPE_BINFO (BINFO_TYPE (binfo)); b; b = TREE_CHAIN (b))
6816       {
6817         if (!BINFO_VIRTUAL_P (b))
6818           continue;
6819
6820         inits = build_vtt_inits (b, t, inits, index);
6821       }
6822   else
6823     /* Remove the ctor vtables we created.  */
6824     dfs_walk_all (binfo, dfs_fixup_binfo_vtbls, NULL, binfo);
6825
6826   return inits;
6827 }
6828
6829 /* Called from build_vtt_inits via dfs_walk.  BINFO is the binfo for the base
6830    in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure.  */
6831
6832 static tree
6833 dfs_build_secondary_vptr_vtt_inits (tree binfo, void *data_)
6834 {
6835   secondary_vptr_vtt_init_data *data = (secondary_vptr_vtt_init_data *)data_;
6836
6837   /* We don't care about bases that don't have vtables.  */
6838   if (!TYPE_VFIELD (BINFO_TYPE (binfo)))
6839     return dfs_skip_bases;
6840
6841   /* We're only interested in proper subobjects of the type being
6842      constructed.  */
6843   if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), data->type_being_constructed))
6844     return NULL_TREE;
6845
6846   /* We're only interested in bases with virtual bases or reachable
6847      via a virtual path from the type being constructed.  */
6848   if (!(CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo))
6849         || binfo_via_virtual (binfo, data->type_being_constructed)))
6850     return dfs_skip_bases;
6851
6852   /* We're not interested in non-virtual primary bases.  */
6853   if (!BINFO_VIRTUAL_P (binfo) && BINFO_PRIMARY_P (binfo))
6854     return NULL_TREE;
6855
6856   /* Record the index where this secondary vptr can be found.  */
6857   if (data->top_level_p)
6858     {
6859       gcc_assert (!BINFO_VPTR_INDEX (binfo));
6860       BINFO_VPTR_INDEX (binfo) = data->index;
6861
6862       if (BINFO_VIRTUAL_P (binfo))
6863         {
6864           /* It's a primary virtual base, and this is not a
6865              construction vtable.  Find the base this is primary of in
6866              the inheritance graph, and use that base's vtable
6867              now.  */
6868           while (BINFO_PRIMARY_P (binfo))
6869             binfo = BINFO_INHERITANCE_CHAIN (binfo);
6870         }
6871     }
6872
6873   /* Add the initializer for the secondary vptr itself.  */
6874   data->inits = tree_cons (NULL_TREE, binfo_ctor_vtable (binfo), data->inits);
6875
6876   /* Advance the vtt index.  */
6877   data->index = size_binop (PLUS_EXPR, data->index,
6878                             TYPE_SIZE_UNIT (ptr_type_node));
6879
6880   return NULL_TREE;
6881 }
6882
6883 /* Called from build_vtt_inits via dfs_walk. After building
6884    constructor vtables and generating the sub-vtt from them, we need
6885    to restore the BINFO_VTABLES that were scribbled on.  DATA is the
6886    binfo of the base whose sub vtt was generated.  */
6887
6888 static tree
6889 dfs_fixup_binfo_vtbls (tree binfo, void* data)
6890 {
6891   tree vtable = BINFO_VTABLE (binfo);
6892
6893   if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
6894     /* If this class has no vtable, none of its bases do.  */
6895     return dfs_skip_bases;
6896
6897   if (!vtable)
6898     /* This might be a primary base, so have no vtable in this
6899        hierarchy.  */
6900     return NULL_TREE;
6901
6902   /* If we scribbled the construction vtable vptr into BINFO, clear it
6903      out now.  */
6904   if (TREE_CODE (vtable) == TREE_LIST
6905       && (TREE_PURPOSE (vtable) == (tree) data))
6906     BINFO_VTABLE (binfo) = TREE_CHAIN (vtable);
6907
6908   return NULL_TREE;
6909 }
6910
6911 /* Build the construction vtable group for BINFO which is in the
6912    hierarchy dominated by T.  */
6913
6914 static void
6915 build_ctor_vtbl_group (tree binfo, tree t)
6916 {
6917   tree list;
6918   tree type;
6919   tree vtbl;
6920   tree inits;
6921   tree id;
6922   tree vbase;
6923
6924   /* See if we've already created this construction vtable group.  */
6925   id = mangle_ctor_vtbl_for_type (t, binfo);
6926   if (IDENTIFIER_GLOBAL_VALUE (id))
6927     return;
6928
6929   gcc_assert (!SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t));
6930   /* Build a version of VTBL (with the wrong type) for use in
6931      constructing the addresses of secondary vtables in the
6932      construction vtable group.  */
6933   vtbl = build_vtable (t, id, ptr_type_node);
6934   DECL_CONSTRUCTION_VTABLE_P (vtbl) = 1;
6935   list = build_tree_list (vtbl, NULL_TREE);
6936   accumulate_vtbl_inits (binfo, TYPE_BINFO (TREE_TYPE (binfo)),
6937                          binfo, t, list);
6938
6939   /* Add the vtables for each of our virtual bases using the vbase in T
6940      binfo.  */
6941   for (vbase = TYPE_BINFO (BINFO_TYPE (binfo));
6942        vbase;
6943        vbase = TREE_CHAIN (vbase))
6944     {
6945       tree b;
6946
6947       if (!BINFO_VIRTUAL_P (vbase))
6948         continue;
6949       b = copied_binfo (vbase, binfo);
6950
6951       accumulate_vtbl_inits (b, vbase, binfo, t, list);
6952     }
6953   inits = TREE_VALUE (list);
6954
6955   /* Figure out the type of the construction vtable.  */
6956   type = build_index_type (size_int (list_length (inits) - 1));
6957   type = build_cplus_array_type (vtable_entry_type, type);
6958   TREE_TYPE (vtbl) = type;
6959
6960   /* Initialize the construction vtable.  */
6961   CLASSTYPE_VTABLES (t) = chainon (CLASSTYPE_VTABLES (t), vtbl);
6962   initialize_artificial_var (vtbl, inits);
6963   dump_vtable (t, binfo, vtbl);
6964 }
6965
6966 /* Add the vtbl initializers for BINFO (and its bases other than
6967    non-virtual primaries) to the list of INITS.  BINFO is in the
6968    hierarchy dominated by T.  RTTI_BINFO is the binfo within T of
6969    the constructor the vtbl inits should be accumulated for. (If this
6970    is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
6971    ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
6972    BINFO is the active base equivalent of ORIG_BINFO in the inheritance
6973    graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
6974    but are not necessarily the same in terms of layout.  */
6975
6976 static void
6977 accumulate_vtbl_inits (tree binfo,
6978                        tree orig_binfo,
6979                        tree rtti_binfo,
6980                        tree t,
6981                        tree inits)
6982 {
6983   int i;
6984   tree base_binfo;
6985   int ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
6986
6987   gcc_assert (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), BINFO_TYPE (orig_binfo)));
6988
6989   /* If it doesn't have a vptr, we don't do anything.  */
6990   if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
6991     return;
6992
6993   /* If we're building a construction vtable, we're not interested in
6994      subobjects that don't require construction vtables.  */
6995   if (ctor_vtbl_p
6996       && !CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo))
6997       && !binfo_via_virtual (orig_binfo, BINFO_TYPE (rtti_binfo)))
6998     return;
6999
7000   /* Build the initializers for the BINFO-in-T vtable.  */
7001   TREE_VALUE (inits)
7002     = chainon (TREE_VALUE (inits),
7003                dfs_accumulate_vtbl_inits (binfo, orig_binfo,
7004                                           rtti_binfo, t, inits));
7005
7006   /* Walk the BINFO and its bases.  We walk in preorder so that as we
7007      initialize each vtable we can figure out at what offset the
7008      secondary vtable lies from the primary vtable.  We can't use
7009      dfs_walk here because we need to iterate through bases of BINFO
7010      and RTTI_BINFO simultaneously.  */
7011   for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
7012     {
7013       /* Skip virtual bases.  */
7014       if (BINFO_VIRTUAL_P (base_binfo))
7015         continue;
7016       accumulate_vtbl_inits (base_binfo,
7017                              BINFO_BASE_BINFO (orig_binfo, i),
7018                              rtti_binfo, t,
7019                              inits);
7020     }
7021 }
7022
7023 /* Called from accumulate_vtbl_inits.  Returns the initializers for
7024    the BINFO vtable.  */
7025
7026 static tree
7027 dfs_accumulate_vtbl_inits (tree binfo,
7028                            tree orig_binfo,
7029                            tree rtti_binfo,
7030                            tree t,
7031                            tree l)
7032 {
7033   tree inits = NULL_TREE;
7034   tree vtbl = NULL_TREE;
7035   int ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
7036
7037   if (ctor_vtbl_p
7038       && BINFO_VIRTUAL_P (orig_binfo) && BINFO_PRIMARY_P (orig_binfo))
7039     {
7040       /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
7041          primary virtual base.  If it is not the same primary in
7042          the hierarchy of T, we'll need to generate a ctor vtable
7043          for it, to place at its location in T.  If it is the same
7044          primary, we still need a VTT entry for the vtable, but it
7045          should point to the ctor vtable for the base it is a
7046          primary for within the sub-hierarchy of RTTI_BINFO.
7047
7048          There are three possible cases:
7049
7050          1) We are in the same place.
7051          2) We are a primary base within a lost primary virtual base of
7052          RTTI_BINFO.
7053          3) We are primary to something not a base of RTTI_BINFO.  */
7054
7055       tree b;
7056       tree last = NULL_TREE;
7057
7058       /* First, look through the bases we are primary to for RTTI_BINFO
7059          or a virtual base.  */
7060       b = binfo;
7061       while (BINFO_PRIMARY_P (b))
7062         {
7063           b = BINFO_INHERITANCE_CHAIN (b);
7064           last = b;
7065           if (BINFO_VIRTUAL_P (b) || b == rtti_binfo)
7066             goto found;
7067         }
7068       /* If we run out of primary links, keep looking down our
7069          inheritance chain; we might be an indirect primary.  */
7070       for (b = last; b; b = BINFO_INHERITANCE_CHAIN (b))
7071         if (BINFO_VIRTUAL_P (b) || b == rtti_binfo)
7072           break;
7073     found:
7074
7075       /* If we found RTTI_BINFO, this is case 1.  If we found a virtual
7076          base B and it is a base of RTTI_BINFO, this is case 2.  In
7077          either case, we share our vtable with LAST, i.e. the
7078          derived-most base within B of which we are a primary.  */
7079       if (b == rtti_binfo
7080           || (b && binfo_for_vbase (BINFO_TYPE (b), BINFO_TYPE (rtti_binfo))))
7081         /* Just set our BINFO_VTABLE to point to LAST, as we may not have
7082            set LAST's BINFO_VTABLE yet.  We'll extract the actual vptr in
7083            binfo_ctor_vtable after everything's been set up.  */
7084         vtbl = last;
7085
7086       /* Otherwise, this is case 3 and we get our own.  */
7087     }
7088   else if (!BINFO_NEW_VTABLE_MARKED (orig_binfo))
7089     return inits;
7090
7091   if (!vtbl)
7092     {
7093       tree index;
7094       int non_fn_entries;
7095
7096       /* Compute the initializer for this vtable.  */
7097       inits = build_vtbl_initializer (binfo, orig_binfo, t, rtti_binfo,
7098                                       &non_fn_entries);
7099
7100       /* Figure out the position to which the VPTR should point.  */
7101       vtbl = TREE_PURPOSE (l);
7102       vtbl = build1 (ADDR_EXPR, vtbl_ptr_type_node, vtbl);
7103       index = size_binop (PLUS_EXPR,
7104                           size_int (non_fn_entries),
7105                           size_int (list_length (TREE_VALUE (l))));
7106       index = size_binop (MULT_EXPR,
7107                           TYPE_SIZE_UNIT (vtable_entry_type),
7108                           index);
7109       vtbl = build2 (PLUS_EXPR, TREE_TYPE (vtbl), vtbl, index);
7110     }
7111
7112   if (ctor_vtbl_p)
7113     /* For a construction vtable, we can't overwrite BINFO_VTABLE.
7114        So, we make a TREE_LIST.  Later, dfs_fixup_binfo_vtbls will
7115        straighten this out.  */
7116     BINFO_VTABLE (binfo) = tree_cons (rtti_binfo, vtbl, BINFO_VTABLE (binfo));
7117   else if (BINFO_PRIMARY_P (binfo) && BINFO_VIRTUAL_P (binfo))
7118     inits = NULL_TREE;
7119   else
7120      /* For an ordinary vtable, set BINFO_VTABLE.  */
7121     BINFO_VTABLE (binfo) = vtbl;
7122
7123   return inits;
7124 }
7125
7126 static GTY(()) tree abort_fndecl_addr;
7127
7128 /* Construct the initializer for BINFO's virtual function table.  BINFO
7129    is part of the hierarchy dominated by T.  If we're building a
7130    construction vtable, the ORIG_BINFO is the binfo we should use to
7131    find the actual function pointers to put in the vtable - but they
7132    can be overridden on the path to most-derived in the graph that
7133    ORIG_BINFO belongs.  Otherwise,
7134    ORIG_BINFO should be the same as BINFO.  The RTTI_BINFO is the
7135    BINFO that should be indicated by the RTTI information in the
7136    vtable; it will be a base class of T, rather than T itself, if we
7137    are building a construction vtable.
7138
7139    The value returned is a TREE_LIST suitable for wrapping in a
7140    CONSTRUCTOR to use as the DECL_INITIAL for a vtable.  If
7141    NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
7142    number of non-function entries in the vtable.
7143
7144    It might seem that this function should never be called with a
7145    BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
7146    base is always subsumed by a derived class vtable.  However, when
7147    we are building construction vtables, we do build vtables for
7148    primary bases; we need these while the primary base is being
7149    constructed.  */
7150
7151 static tree
7152 build_vtbl_initializer (tree binfo,
7153                         tree orig_binfo,
7154                         tree t,
7155                         tree rtti_binfo,
7156                         int* non_fn_entries_p)
7157 {
7158   tree v, b;
7159   tree vfun_inits;
7160   vtbl_init_data vid;
7161   unsigned ix;
7162   tree vbinfo;
7163   VEC(tree,gc) *vbases;
7164
7165   /* Initialize VID.  */
7166   memset (&vid, 0, sizeof (vid));
7167   vid.binfo = binfo;
7168   vid.derived = t;
7169   vid.rtti_binfo = rtti_binfo;
7170   vid.last_init = &vid.inits;
7171   vid.primary_vtbl_p = SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t);
7172   vid.ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
7173   vid.generate_vcall_entries = true;
7174   /* The first vbase or vcall offset is at index -3 in the vtable.  */
7175   vid.index = ssize_int(-3 * TARGET_VTABLE_DATA_ENTRY_DISTANCE);
7176
7177   /* Add entries to the vtable for RTTI.  */
7178   build_rtti_vtbl_entries (binfo, &vid);
7179
7180   /* Create an array for keeping track of the functions we've
7181      processed.  When we see multiple functions with the same
7182      signature, we share the vcall offsets.  */
7183   vid.fns = VEC_alloc (tree, gc, 32);
7184   /* Add the vcall and vbase offset entries.  */
7185   build_vcall_and_vbase_vtbl_entries (binfo, &vid);
7186
7187   /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
7188      build_vbase_offset_vtbl_entries.  */
7189   for (vbases = CLASSTYPE_VBASECLASSES (t), ix = 0;
7190        VEC_iterate (tree, vbases, ix, vbinfo); ix++)
7191     BINFO_VTABLE_PATH_MARKED (vbinfo) = 0;
7192
7193   /* If the target requires padding between data entries, add that now.  */
7194   if (TARGET_VTABLE_DATA_ENTRY_DISTANCE > 1)
7195     {
7196       tree cur, *prev;
7197
7198       for (prev = &vid.inits; (cur = *prev); prev = &TREE_CHAIN (cur))
7199         {
7200           tree add = cur;
7201           int i;
7202
7203           for (i = 1; i < TARGET_VTABLE_DATA_ENTRY_DISTANCE; ++i)
7204             add = tree_cons (NULL_TREE,
7205                              build1 (NOP_EXPR, vtable_entry_type,
7206                                      null_pointer_node),
7207                              add);
7208           *prev = add;
7209         }
7210     }
7211
7212   if (non_fn_entries_p)
7213     *non_fn_entries_p = list_length (vid.inits);
7214
7215   /* Go through all the ordinary virtual functions, building up
7216      initializers.  */
7217   vfun_inits = NULL_TREE;
7218   for (v = BINFO_VIRTUALS (orig_binfo); v; v = TREE_CHAIN (v))
7219     {
7220       tree delta;
7221       tree vcall_index;
7222       tree fn, fn_original;
7223       tree init = NULL_TREE;
7224
7225       fn = BV_FN (v);
7226       fn_original = fn;
7227       if (DECL_THUNK_P (fn))
7228         {
7229           if (!DECL_NAME (fn))
7230             finish_thunk (fn);
7231           if (THUNK_ALIAS (fn))
7232             {
7233               fn = THUNK_ALIAS (fn);
7234               BV_FN (v) = fn;
7235             }
7236           fn_original = THUNK_TARGET (fn);
7237         }
7238
7239       /* If the only definition of this function signature along our
7240          primary base chain is from a lost primary, this vtable slot will
7241          never be used, so just zero it out.  This is important to avoid
7242          requiring extra thunks which cannot be generated with the function.
7243
7244          We first check this in update_vtable_entry_for_fn, so we handle
7245          restored primary bases properly; we also need to do it here so we
7246          zero out unused slots in ctor vtables, rather than filling themff
7247          with erroneous values (though harmless, apart from relocation
7248          costs).  */
7249       for (b = binfo; ; b = get_primary_binfo (b))
7250         {
7251           /* We found a defn before a lost primary; go ahead as normal.  */
7252           if (look_for_overrides_here (BINFO_TYPE (b), fn_original))
7253             break;
7254
7255           /* The nearest definition is from a lost primary; clear the
7256              slot.  */
7257           if (BINFO_LOST_PRIMARY_P (b))
7258             {
7259               init = size_zero_node;
7260               break;
7261             }
7262         }
7263
7264       if (! init)
7265         {
7266           /* Pull the offset for `this', and the function to call, out of
7267              the list.  */
7268           delta = BV_DELTA (v);
7269           vcall_index = BV_VCALL_INDEX (v);
7270
7271           gcc_assert (TREE_CODE (delta) == INTEGER_CST);
7272           gcc_assert (TREE_CODE (fn) == FUNCTION_DECL);
7273
7274           /* You can't call an abstract virtual function; it's abstract.
7275              So, we replace these functions with __pure_virtual.  */
7276           if (DECL_PURE_VIRTUAL_P (fn_original))
7277             {
7278               fn = abort_fndecl;
7279               if (abort_fndecl_addr == NULL)
7280                 abort_fndecl_addr = build1 (ADDR_EXPR, vfunc_ptr_type_node, fn);
7281               init = abort_fndecl_addr;
7282             }
7283           else
7284             {
7285               if (!integer_zerop (delta) || vcall_index)
7286                 {
7287                   fn = make_thunk (fn, /*this_adjusting=*/1, delta, vcall_index);
7288                   if (!DECL_NAME (fn))
7289                     finish_thunk (fn);
7290                 }
7291               /* Take the address of the function, considering it to be of an
7292                  appropriate generic type.  */
7293               init = build1 (ADDR_EXPR, vfunc_ptr_type_node, fn);
7294             }
7295         }
7296
7297       /* And add it to the chain of initializers.  */
7298       if (TARGET_VTABLE_USES_DESCRIPTORS)
7299         {
7300           int i;
7301           if (init == size_zero_node)
7302             for (i = 0; i < TARGET_VTABLE_USES_DESCRIPTORS; ++i)
7303               vfun_inits = tree_cons (NULL_TREE, init, vfun_inits);
7304           else
7305             for (i = 0; i < TARGET_VTABLE_USES_DESCRIPTORS; ++i)
7306               {
7307                 tree fdesc = build2 (FDESC_EXPR, vfunc_ptr_type_node,
7308                                      TREE_OPERAND (init, 0),
7309                                      build_int_cst (NULL_TREE, i));
7310                 TREE_CONSTANT (fdesc) = 1;
7311                 TREE_INVARIANT (fdesc) = 1;
7312
7313                 vfun_inits = tree_cons (NULL_TREE, fdesc, vfun_inits);
7314               }
7315         }
7316       else
7317         vfun_inits = tree_cons (NULL_TREE, init, vfun_inits);
7318     }
7319
7320   /* The initializers for virtual functions were built up in reverse
7321      order; straighten them out now.  */
7322   vfun_inits = nreverse (vfun_inits);
7323
7324   /* The negative offset initializers are also in reverse order.  */
7325   vid.inits = nreverse (vid.inits);
7326
7327   /* Chain the two together.  */
7328   return chainon (vid.inits, vfun_inits);
7329 }
7330
7331 /* Adds to vid->inits the initializers for the vbase and vcall
7332    offsets in BINFO, which is in the hierarchy dominated by T.  */
7333
7334 static void
7335 build_vcall_and_vbase_vtbl_entries (tree binfo, vtbl_init_data* vid)
7336 {
7337   tree b;
7338
7339   /* If this is a derived class, we must first create entries
7340      corresponding to the primary base class.  */
7341   b = get_primary_binfo (binfo);
7342   if (b)
7343     build_vcall_and_vbase_vtbl_entries (b, vid);
7344
7345   /* Add the vbase entries for this base.  */
7346   build_vbase_offset_vtbl_entries (binfo, vid);
7347   /* Add the vcall entries for this base.  */
7348   build_vcall_offset_vtbl_entries (binfo, vid);
7349 }
7350
7351 /* Returns the initializers for the vbase offset entries in the vtable
7352    for BINFO (which is part of the class hierarchy dominated by T), in
7353    reverse order.  VBASE_OFFSET_INDEX gives the vtable index
7354    where the next vbase offset will go.  */
7355
7356 static void
7357 build_vbase_offset_vtbl_entries (tree binfo, vtbl_init_data* vid)
7358 {
7359   tree vbase;
7360   tree t;
7361   tree non_primary_binfo;
7362
7363   /* If there are no virtual baseclasses, then there is nothing to
7364      do.  */
7365   if (!CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo)))
7366     return;
7367
7368   t = vid->derived;
7369
7370   /* We might be a primary base class.  Go up the inheritance hierarchy
7371      until we find the most derived class of which we are a primary base:
7372      it is the offset of that which we need to use.  */
7373   non_primary_binfo = binfo;
7374   while (BINFO_INHERITANCE_CHAIN (non_primary_binfo))
7375     {
7376       tree b;
7377
7378       /* If we have reached a virtual base, then it must be a primary
7379          base (possibly multi-level) of vid->binfo, or we wouldn't
7380          have called build_vcall_and_vbase_vtbl_entries for it.  But it
7381          might be a lost primary, so just skip down to vid->binfo.  */
7382       if (BINFO_VIRTUAL_P (non_primary_binfo))
7383         {
7384           non_primary_binfo = vid->binfo;
7385           break;
7386         }
7387
7388       b = BINFO_INHERITANCE_CHAIN (non_primary_binfo);
7389       if (get_primary_binfo (b) != non_primary_binfo)
7390         break;
7391       non_primary_binfo = b;
7392     }
7393
7394   /* Go through the virtual bases, adding the offsets.  */
7395   for (vbase = TYPE_BINFO (BINFO_TYPE (binfo));
7396        vbase;
7397        vbase = TREE_CHAIN (vbase))
7398     {
7399       tree b;
7400       tree delta;
7401
7402       if (!BINFO_VIRTUAL_P (vbase))
7403         continue;
7404
7405       /* Find the instance of this virtual base in the complete
7406          object.  */
7407       b = copied_binfo (vbase, binfo);
7408
7409       /* If we've already got an offset for this virtual base, we
7410          don't need another one.  */
7411       if (BINFO_VTABLE_PATH_MARKED (b))
7412         continue;
7413       BINFO_VTABLE_PATH_MARKED (b) = 1;
7414
7415       /* Figure out where we can find this vbase offset.  */
7416       delta = size_binop (MULT_EXPR,
7417                           vid->index,
7418                           convert (ssizetype,
7419                                    TYPE_SIZE_UNIT (vtable_entry_type)));
7420       if (vid->primary_vtbl_p)
7421         BINFO_VPTR_FIELD (b) = delta;
7422
7423       if (binfo != TYPE_BINFO (t))
7424         /* The vbase offset had better be the same.  */
7425         gcc_assert (tree_int_cst_equal (delta, BINFO_VPTR_FIELD (vbase)));
7426
7427       /* The next vbase will come at a more negative offset.  */
7428       vid->index = size_binop (MINUS_EXPR, vid->index,
7429                                ssize_int (TARGET_VTABLE_DATA_ENTRY_DISTANCE));
7430
7431       /* The initializer is the delta from BINFO to this virtual base.
7432          The vbase offsets go in reverse inheritance-graph order, and
7433          we are walking in inheritance graph order so these end up in
7434          the right order.  */
7435       delta = size_diffop (BINFO_OFFSET (b), BINFO_OFFSET (non_primary_binfo));
7436
7437       *vid->last_init
7438         = build_tree_list (NULL_TREE,
7439                            fold_build1 (NOP_EXPR,
7440                                         vtable_entry_type,
7441                                         delta));
7442       vid->last_init = &TREE_CHAIN (*vid->last_init);
7443     }
7444 }
7445
7446 /* Adds the initializers for the vcall offset entries in the vtable
7447    for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
7448    to VID->INITS.  */
7449
7450 static void
7451 build_vcall_offset_vtbl_entries (tree binfo, vtbl_init_data* vid)
7452 {
7453   /* We only need these entries if this base is a virtual base.  We
7454      compute the indices -- but do not add to the vtable -- when
7455      building the main vtable for a class.  */
7456   if (binfo == TYPE_BINFO (vid->derived)
7457       || (BINFO_VIRTUAL_P (binfo)
7458           /* If BINFO is RTTI_BINFO, then (since BINFO does not
7459              correspond to VID->DERIVED), we are building a primary
7460              construction virtual table.  Since this is a primary
7461              virtual table, we do not need the vcall offsets for
7462              BINFO.  */
7463           && binfo != vid->rtti_binfo))
7464     {
7465       /* We need a vcall offset for each of the virtual functions in this
7466          vtable.  For example:
7467
7468            class A { virtual void f (); };
7469            class B1 : virtual public A { virtual void f (); };
7470            class B2 : virtual public A { virtual void f (); };
7471            class C: public B1, public B2 { virtual void f (); };
7472
7473          A C object has a primary base of B1, which has a primary base of A.  A
7474          C also has a secondary base of B2, which no longer has a primary base
7475          of A.  So the B2-in-C construction vtable needs a secondary vtable for
7476          A, which will adjust the A* to a B2* to call f.  We have no way of
7477          knowing what (or even whether) this offset will be when we define B2,
7478          so we store this "vcall offset" in the A sub-vtable and look it up in
7479          a "virtual thunk" for B2::f.
7480
7481          We need entries for all the functions in our primary vtable and
7482          in our non-virtual bases' secondary vtables.  */
7483       vid->vbase = binfo;
7484       /* If we are just computing the vcall indices -- but do not need
7485          the actual entries -- not that.  */
7486       if (!BINFO_VIRTUAL_P (binfo))
7487         vid->generate_vcall_entries = false;
7488       /* Now, walk through the non-virtual bases, adding vcall offsets.  */
7489       add_vcall_offset_vtbl_entries_r (binfo, vid);
7490     }
7491 }
7492
7493 /* Build vcall offsets, starting with those for BINFO.  */
7494
7495 static void
7496 add_vcall_offset_vtbl_entries_r (tree binfo, vtbl_init_data* vid)
7497 {
7498   int i;
7499   tree primary_binfo;
7500   tree base_binfo;
7501
7502   /* Don't walk into virtual bases -- except, of course, for the
7503      virtual base for which we are building vcall offsets.  Any
7504      primary virtual base will have already had its offsets generated
7505      through the recursion in build_vcall_and_vbase_vtbl_entries.  */
7506   if (BINFO_VIRTUAL_P (binfo) && vid->vbase != binfo)
7507     return;
7508
7509   /* If BINFO has a primary base, process it first.  */
7510   primary_binfo = get_primary_binfo (binfo);
7511   if (primary_binfo)
7512     add_vcall_offset_vtbl_entries_r (primary_binfo, vid);
7513
7514   /* Add BINFO itself to the list.  */
7515   add_vcall_offset_vtbl_entries_1 (binfo, vid);
7516
7517   /* Scan the non-primary bases of BINFO.  */
7518   for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
7519     if (base_binfo != primary_binfo)
7520       add_vcall_offset_vtbl_entries_r (base_binfo, vid);
7521 }
7522
7523 /* Called from build_vcall_offset_vtbl_entries_r.  */
7524
7525 static void
7526 add_vcall_offset_vtbl_entries_1 (tree binfo, vtbl_init_data* vid)
7527 {
7528   /* Make entries for the rest of the virtuals.  */
7529   if (abi_version_at_least (2))
7530     {
7531       tree orig_fn;
7532
7533       /* The ABI requires that the methods be processed in declaration
7534          order.  G++ 3.2 used the order in the vtable.  */
7535       for (orig_fn = TYPE_METHODS (BINFO_TYPE (binfo));
7536            orig_fn;
7537            orig_fn = TREE_CHAIN (orig_fn))
7538         if (DECL_VINDEX (orig_fn))
7539           add_vcall_offset (orig_fn, binfo, vid);
7540     }
7541   else
7542     {
7543       tree derived_virtuals;
7544       tree base_virtuals;
7545       tree orig_virtuals;
7546       /* If BINFO is a primary base, the most derived class which has
7547          BINFO as a primary base; otherwise, just BINFO.  */
7548       tree non_primary_binfo;
7549
7550       /* We might be a primary base class.  Go up the inheritance hierarchy
7551          until we find the most derived class of which we are a primary base:
7552          it is the BINFO_VIRTUALS there that we need to consider.  */
7553       non_primary_binfo = binfo;
7554       while (BINFO_INHERITANCE_CHAIN (non_primary_binfo))
7555         {
7556           tree b;
7557
7558           /* If we have reached a virtual base, then it must be vid->vbase,
7559              because we ignore other virtual bases in
7560              add_vcall_offset_vtbl_entries_r.  In turn, it must be a primary
7561              base (possibly multi-level) of vid->binfo, or we wouldn't
7562              have called build_vcall_and_vbase_vtbl_entries for it.  But it
7563              might be a lost primary, so just skip down to vid->binfo.  */
7564           if (BINFO_VIRTUAL_P (non_primary_binfo))
7565             {
7566               gcc_assert (non_primary_binfo == vid->vbase);
7567               non_primary_binfo = vid->binfo;
7568               break;
7569             }
7570
7571           b = BINFO_INHERITANCE_CHAIN (non_primary_binfo);
7572           if (get_primary_binfo (b) != non_primary_binfo)
7573             break;
7574           non_primary_binfo = b;
7575         }
7576
7577       if (vid->ctor_vtbl_p)
7578         /* For a ctor vtable we need the equivalent binfo within the hierarchy
7579            where rtti_binfo is the most derived type.  */
7580         non_primary_binfo
7581           = original_binfo (non_primary_binfo, vid->rtti_binfo);
7582
7583       for (base_virtuals = BINFO_VIRTUALS (binfo),
7584              derived_virtuals = BINFO_VIRTUALS (non_primary_binfo),
7585              orig_virtuals = BINFO_VIRTUALS (TYPE_BINFO (BINFO_TYPE (binfo)));
7586            base_virtuals;
7587            base_virtuals = TREE_CHAIN (base_virtuals),
7588              derived_virtuals = TREE_CHAIN (derived_virtuals),
7589              orig_virtuals = TREE_CHAIN (orig_virtuals))
7590         {
7591           tree orig_fn;
7592
7593           /* Find the declaration that originally caused this function to
7594              be present in BINFO_TYPE (binfo).  */
7595           orig_fn = BV_FN (orig_virtuals);
7596
7597           /* When processing BINFO, we only want to generate vcall slots for
7598              function slots introduced in BINFO.  So don't try to generate
7599              one if the function isn't even defined in BINFO.  */
7600           if (!SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), DECL_CONTEXT (orig_fn)))
7601             continue;
7602
7603           add_vcall_offset (orig_fn, binfo, vid);
7604         }
7605     }
7606 }
7607
7608 /* Add a vcall offset entry for ORIG_FN to the vtable.  */
7609
7610 static void
7611 add_vcall_offset (tree orig_fn, tree binfo, vtbl_init_data *vid)
7612 {
7613   size_t i;
7614   tree vcall_offset;
7615   tree derived_entry;
7616
7617   /* If there is already an entry for a function with the same
7618      signature as FN, then we do not need a second vcall offset.
7619      Check the list of functions already present in the derived
7620      class vtable.  */
7621   for (i = 0; VEC_iterate (tree, vid->fns, i, derived_entry); ++i)
7622     {
7623       if (same_signature_p (derived_entry, orig_fn)
7624           /* We only use one vcall offset for virtual destructors,
7625              even though there are two virtual table entries.  */
7626           || (DECL_DESTRUCTOR_P (derived_entry)
7627               && DECL_DESTRUCTOR_P (orig_fn)))
7628         return;
7629     }
7630
7631   /* If we are building these vcall offsets as part of building
7632      the vtable for the most derived class, remember the vcall
7633      offset.  */
7634   if (vid->binfo == TYPE_BINFO (vid->derived))
7635     {
7636       tree_pair_p elt = VEC_safe_push (tree_pair_s, gc,
7637                                        CLASSTYPE_VCALL_INDICES (vid->derived),
7638                                        NULL);
7639       elt->purpose = orig_fn;
7640       elt->value = vid->index;
7641     }
7642
7643   /* The next vcall offset will be found at a more negative
7644      offset.  */
7645   vid->index = size_binop (MINUS_EXPR, vid->index,
7646                            ssize_int (TARGET_VTABLE_DATA_ENTRY_DISTANCE));
7647
7648   /* Keep track of this function.  */
7649   VEC_safe_push (tree, gc, vid->fns, orig_fn);
7650
7651   if (vid->generate_vcall_entries)
7652     {
7653       tree base;
7654       tree fn;
7655
7656       /* Find the overriding function.  */
7657       fn = find_final_overrider (vid->rtti_binfo, binfo, orig_fn);
7658       if (fn == error_mark_node)
7659         vcall_offset = build1 (NOP_EXPR, vtable_entry_type,
7660                                integer_zero_node);
7661       else
7662         {
7663           base = TREE_VALUE (fn);
7664
7665           /* The vbase we're working on is a primary base of
7666              vid->binfo.  But it might be a lost primary, so its
7667              BINFO_OFFSET might be wrong, so we just use the
7668              BINFO_OFFSET from vid->binfo.  */
7669           vcall_offset = size_diffop (BINFO_OFFSET (base),
7670                                       BINFO_OFFSET (vid->binfo));
7671           vcall_offset = fold_build1 (NOP_EXPR, vtable_entry_type,
7672                                       vcall_offset);
7673         }
7674       /* Add the initializer to the vtable.  */
7675       *vid->last_init = build_tree_list (NULL_TREE, vcall_offset);
7676       vid->last_init = &TREE_CHAIN (*vid->last_init);
7677     }
7678 }
7679
7680 /* Return vtbl initializers for the RTTI entries corresponding to the
7681    BINFO's vtable.  The RTTI entries should indicate the object given
7682    by VID->rtti_binfo.  */
7683
7684 static void
7685 build_rtti_vtbl_entries (tree binfo, vtbl_init_data* vid)
7686 {
7687   tree b;
7688   tree t;
7689   tree basetype;
7690   tree offset;
7691   tree decl;
7692   tree init;
7693
7694   basetype = BINFO_TYPE (binfo);
7695   t = BINFO_TYPE (vid->rtti_binfo);
7696
7697   /* To find the complete object, we will first convert to our most
7698      primary base, and then add the offset in the vtbl to that value.  */
7699   b = binfo;
7700   while (CLASSTYPE_HAS_PRIMARY_BASE_P (BINFO_TYPE (b))
7701          && !BINFO_LOST_PRIMARY_P (b))
7702     {
7703       tree primary_base;
7704
7705       primary_base = get_primary_binfo (b);
7706       gcc_assert (BINFO_PRIMARY_P (primary_base)
7707                   && BINFO_INHERITANCE_CHAIN (primary_base) == b);
7708       b = primary_base;
7709     }
7710   offset = size_diffop (BINFO_OFFSET (vid->rtti_binfo), BINFO_OFFSET (b));
7711
7712   /* The second entry is the address of the typeinfo object.  */
7713   if (flag_rtti)
7714     decl = build_address (get_tinfo_decl (t));
7715   else
7716     decl = integer_zero_node;
7717
7718   /* Convert the declaration to a type that can be stored in the
7719      vtable.  */
7720   init = build_nop (vfunc_ptr_type_node, decl);
7721   *vid->last_init = build_tree_list (NULL_TREE, init);
7722   vid->last_init = &TREE_CHAIN (*vid->last_init);
7723
7724   /* Add the offset-to-top entry.  It comes earlier in the vtable than
7725      the typeinfo entry.  Convert the offset to look like a
7726      function pointer, so that we can put it in the vtable.  */
7727   init = build_nop (vfunc_ptr_type_node, offset);
7728   *vid->last_init = build_tree_list (NULL_TREE, init);
7729   vid->last_init = &TREE_CHAIN (*vid->last_init);
7730 }
7731
7732 /* Fold a OBJ_TYPE_REF expression to the address of a function.
7733    KNOWN_TYPE carries the true type of OBJ_TYPE_REF_OBJECT(REF).  */
7734
7735 tree
7736 cp_fold_obj_type_ref (tree ref, tree known_type)
7737 {
7738   HOST_WIDE_INT index = tree_low_cst (OBJ_TYPE_REF_TOKEN (ref), 1);
7739   HOST_WIDE_INT i = 0;
7740   tree v = BINFO_VIRTUALS (TYPE_BINFO (known_type));
7741   tree fndecl;
7742
7743   while (i != index)
7744     {
7745       i += (TARGET_VTABLE_USES_DESCRIPTORS
7746             ? TARGET_VTABLE_USES_DESCRIPTORS : 1);
7747       v = TREE_CHAIN (v);
7748     }
7749
7750   fndecl = BV_FN (v);
7751
7752 #ifdef ENABLE_CHECKING
7753   gcc_assert (tree_int_cst_equal (OBJ_TYPE_REF_TOKEN (ref),
7754                                   DECL_VINDEX (fndecl)));
7755 #endif
7756
7757   cgraph_node (fndecl)->local.vtable_method = true;
7758
7759   return build_address (fndecl);
7760 }
7761
7762 #include "gt-cp-class.h"