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  Free Software Foundation, Inc.
   4    Contributed by Michael Tiemann (tiemann@cygnus.com)
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  21 Boston, MA 02110-1301, USA.  */
  22
  23
  24 /* High-level class interface.  */
  25
  26 #include "config.h"
  27 #include "system.h"
  28 #include "coretypes.h"
  29 #include "tm.h"
  30 #include "tree.h"
  31 #include "cp-tree.h"
  32 #include "flags.h"
  33 #include "rtl.h"
  34 #include "output.h"
  35 #include "toplev.h"
  36 #include "target.h"
  37 #include "convert.h"
  38 #include "cgraph.h"
  39 #include "tree-dump.h"
  40
  41 /* The number of nested classes being processed.  If we are not in the
  42    scope of any class, this is zero.  */
  43
  44 int current_class_depth;
  45
  46 /* In order to deal with nested classes, we keep a stack of classes.
  47    The topmost entry is the innermost class, and is the entry at index
  48    CURRENT_CLASS_DEPTH  */
  49
  50 typedef struct class_stack_node {
  51   /* The name of the class.  */
  52   tree name;
  53
  54   /* The _TYPE node for the class.  */
  55   tree type;
  56
  57   /* The access specifier pending for new declarations in the scope of
  58      this class.  */
  59   tree access;
  60
  61   /* If were defining TYPE, the names used in this class.  */
  62   splay_tree names_used;
  63
  64   /* Nonzero if this class is no longer open, because of a call to
  65      push_to_top_level.  */
  66   size_t hidden;
  67 }* class_stack_node_t;
  68
  69 typedef struct vtbl_init_data_s
  70 {
  71   /* The base for which we're building initializers.  */
  72   tree binfo;
  73   /* The type of the most-derived type.  */
  74   tree derived;
  75   /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
  76      unless ctor_vtbl_p is true.  */
  77   tree rtti_binfo;
  78   /* The negative-index vtable initializers built up so far.  These
  79      are in order from least negative index to most negative index.  */
  80   tree inits;
  81   /* The last (i.e., most negative) entry in INITS.  */
  82   tree* last_init;
  83   /* The binfo for the virtual base for which we're building
  84      vcall offset initializers.  */
  85   tree vbase;
  86   /* The functions in vbase for which we have already provided vcall
  87      offsets.  */
  88   VEC(tree,gc) *fns;
  89   /* The vtable index of the next vcall or vbase offset.  */
  90   tree index;
  91   /* Nonzero if we are building the initializer for the primary
  92      vtable.  */
  93   int primary_vtbl_p;
  94   /* Nonzero if we are building the initializer for a construction
  95      vtable.  */
  96   int ctor_vtbl_p;
  97   /* True when adding vcall offset entries to the vtable.  False when
  98      merely computing the indices.  */
  99   bool generate_vcall_entries;
 100 } vtbl_init_data;
 101
 102 /* The type of a function passed to walk_subobject_offsets.  */
 103 typedef int (*subobject_offset_fn) (tree, tree, splay_tree);
 104
 105 /* The stack itself.  This is a dynamically resized array.  The
 106    number of elements allocated is CURRENT_CLASS_STACK_SIZE.  */
 107 static int current_class_stack_size;
 108 static class_stack_node_t current_class_stack;
 109
 110 /* The size of the largest empty class seen in this translation unit.  */
 111 static GTY (()) tree sizeof_biggest_empty_class;
 112
 113 /* An array of all local classes present in this translation unit, in
 114    declaration order.  */
 115 VEC(tree,gc) *local_classes;
 116
 117 static tree get_vfield_name (tree);
 118 static void finish_struct_anon (tree);
 119 static tree get_vtable_name (tree);
 120 static tree get_basefndecls (tree, tree);
 121 static int build_primary_vtable (tree, tree);
 122 static int build_secondary_vtable (tree);
 123 static void finish_vtbls (tree);
 124 static void modify_vtable_entry (tree, tree, tree, tree, tree *);
 125 static void finish_struct_bits (tree);
 126 static int alter_access (tree, tree, tree);
 127 static void handle_using_decl (tree, tree);
 128 static tree dfs_modify_vtables (tree, void *);
 129 static tree modify_all_vtables (tree, tree);
 130 static void determine_primary_bases (tree);
 131 static void finish_struct_methods (tree);
 132 static void maybe_warn_about_overly_private_class (tree);
 133 static int method_name_cmp (const void *, const void *);
 134 static int resort_method_name_cmp (const void *, const void *);
 135 static void add_implicitly_declared_members (tree, int, int);
 136 static tree fixed_type_or_null (tree, int *, int *);
 137 static tree resolve_address_of_overloaded_function (tree, tree, tsubst_flags_t,
 138                                                     bool, tree);
 139 static tree build_simple_base_path (tree expr, tree binfo);
 140 static tree build_vtbl_ref_1 (tree, tree);
 141 static tree build_vtbl_initializer (tree, tree, tree, tree, int *);
 142 static int count_fields (tree);
 143 static int add_fields_to_record_type (tree, struct sorted_fields_type*, int);
 144 static void check_bitfield_decl (tree);
 145 static void check_field_decl (tree, tree, int *, int *, int *);
 146 static void check_field_decls (tree, tree *, int *, int *);
 147 static tree *build_base_field (record_layout_info, tree, splay_tree, tree *);
 148 static void build_base_fields (record_layout_info, splay_tree, tree *);
 149 static void check_methods (tree);
 150 static void remove_zero_width_bit_fields (tree);
 151 static void check_bases (tree, int *, int *);
 152 static void check_bases_and_members (tree);
 153 static tree create_vtable_ptr (tree, tree *);
 154 static void include_empty_classes (record_layout_info);
 155 static void layout_class_type (tree, tree *);
 156 static void fixup_pending_inline (tree);
 157 static void fixup_inline_methods (tree);
 158 static void propagate_binfo_offsets (tree, tree);
 159 static void layout_virtual_bases (record_layout_info, splay_tree);
 160 static void build_vbase_offset_vtbl_entries (tree, vtbl_init_data *);
 161 static void add_vcall_offset_vtbl_entries_r (tree, vtbl_init_data *);
 162 static void add_vcall_offset_vtbl_entries_1 (tree, vtbl_init_data *);
 163 static void build_vcall_offset_vtbl_entries (tree, vtbl_init_data *);
 164 static void add_vcall_offset (tree, tree, vtbl_init_data *);
 165 static void layout_vtable_decl (tree, int);
 166 static tree dfs_find_final_overrider_pre (tree, void *);
 167 static tree dfs_find_final_overrider_post (tree, void *);
 168 static tree find_final_overrider (tree, tree, tree);
 169 static int make_new_vtable (tree, tree);
 170 static tree get_primary_binfo (tree);
 171 static int maybe_indent_hierarchy (FILE *, int, int);
 172 static tree dump_class_hierarchy_r (FILE *, int, tree, tree, int);
 173 static void dump_class_hierarchy (tree);
 174 static void dump_class_hierarchy_1 (FILE *, int, tree);
 175 static void dump_array (FILE *, tree);
 176 static void dump_vtable (tree, tree, tree);
 177 static void dump_vtt (tree, tree);
 178 static void dump_thunk (FILE *, int, tree);
 179 static tree build_vtable (tree, tree, tree);
 180 static void initialize_vtable (tree, tree);
 181 static void layout_nonempty_base_or_field (record_layout_info,
 182                                            tree, tree, splay_tree);
 183 static tree end_of_class (tree, int);
 184 static bool layout_empty_base (tree, tree, splay_tree);
 185 static void accumulate_vtbl_inits (tree, tree, tree, tree, tree);
 186 static tree dfs_accumulate_vtbl_inits (tree, tree, tree, tree,
 187                                                tree);
 188 static void build_rtti_vtbl_entries (tree, vtbl_init_data *);
 189 static void build_vcall_and_vbase_vtbl_entries (tree, vtbl_init_data *);
 190 static void clone_constructors_and_destructors (tree);
 191 static tree build_clone (tree, tree);
 192 static void update_vtable_entry_for_fn (tree, tree, tree, tree *, unsigned);
 193 static void build_ctor_vtbl_group (tree, tree);
 194 static void build_vtt (tree);
 195 static tree binfo_ctor_vtable (tree);
 196 static tree *build_vtt_inits (tree, tree, tree *, tree *);
 197 static tree dfs_build_secondary_vptr_vtt_inits (tree, void *);
 198 static tree dfs_fixup_binfo_vtbls (tree, void *);
 199 static int record_subobject_offset (tree, tree, splay_tree);
 200 static int check_subobject_offset (tree, tree, splay_tree);
 201 static int walk_subobject_offsets (tree, subobject_offset_fn,
 202                                    tree, splay_tree, tree, int);
 203 static void record_subobject_offsets (tree, tree, splay_tree, bool);
 204 static int layout_conflict_p (tree, tree, splay_tree, int);
 205 static int splay_tree_compare_integer_csts (splay_tree_key k1,
 206                                             splay_tree_key k2);
 207 static void warn_about_ambiguous_bases (tree);
 208 static bool type_requires_array_cookie (tree);
 209 static bool contains_empty_class_p (tree);
 210 static bool base_derived_from (tree, tree);
 211 static int empty_base_at_nonzero_offset_p (tree, tree, splay_tree);
 212 static tree end_of_base (tree);
 213 static tree get_vcall_index (tree, tree);
 214
 215 /* Variables shared between class.c and call.c.  */
 216
 217 #ifdef GATHER_STATISTICS
 218 int n_vtables = 0;
 219 int n_vtable_entries = 0;
 220 int n_vtable_searches = 0;
 221 int n_vtable_elems = 0;
 222 int n_convert_harshness = 0;
 223 int n_compute_conversion_costs = 0;
 224 int n_inner_fields_searched = 0;
 225 #endif
 226
 227 /* Convert to or from a base subobject.  EXPR is an expression of type
 228    `A' or `A*', an expression of type `B' or `B*' is returned.  To
 229    convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
 230    the B base instance within A.  To convert base A to derived B, CODE
 231    is MINUS_EXPR and BINFO is the binfo for the A instance within B.
 232    In this latter case, A must not be a morally virtual base of B.
 233    NONNULL is true if EXPR is known to be non-NULL (this is only
 234    needed when EXPR is of pointer type).  CV qualifiers are preserved
 235    from EXPR.  */
 236
 237 tree
 238 build_base_path (enum tree_code code,
 239                  tree expr,
 240                  tree binfo,
 241                  int nonnull)
 242 {
 243   tree v_binfo = NULL_TREE;
 244   tree d_binfo = NULL_TREE;
 245   tree probe;
 246   tree offset;
 247   tree target_type;
 248   tree null_test = NULL;
 249   tree ptr_target_type;
 250   int fixed_type_p;
 251   int want_pointer = TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE;
 252   bool has_empty = false;
 253   bool virtual_access;
 254
 255   if (expr == error_mark_node || binfo == error_mark_node || !binfo)
 256     return error_mark_node;
 257
 258   for (probe = binfo; probe; probe = BINFO_INHERITANCE_CHAIN (probe))
 259     {
 260       d_binfo = probe;
 261       if (is_empty_class (BINFO_TYPE (probe)))
 262         has_empty = true;
 263       if (!v_binfo && BINFO_VIRTUAL_P (probe))
 264         v_binfo = probe;
 265     }
 266
 267   probe = TYPE_MAIN_VARIANT (TREE_TYPE (expr));
 268   if (want_pointer)
 269     probe = TYPE_MAIN_VARIANT (TREE_TYPE (probe));
 270
 271   gcc_assert ((code == MINUS_EXPR
 272                && SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), probe))
 273               || (code == PLUS_EXPR
 274                   && SAME_BINFO_TYPE_P (BINFO_TYPE (d_binfo), probe)));
 275
 276   if (binfo == d_binfo)
 277     /* Nothing to do.  */
 278     return expr;
 279
 280   if (code == MINUS_EXPR && v_binfo)
 281     {
 282       error ("cannot convert from base %qT to derived type %qT via virtual base %qT",
 283              BINFO_TYPE (binfo), BINFO_TYPE (d_binfo), BINFO_TYPE (v_binfo));
 284       return error_mark_node;
 285     }
 286
 287   if (!want_pointer)
 288     /* This must happen before the call to save_expr.  */
 289     expr = build_unary_op (ADDR_EXPR, expr, 0);
 290
 291   offset = BINFO_OFFSET (binfo);
 292   fixed_type_p = resolves_to_fixed_type_p (expr, &nonnull);
 293   target_type = code == PLUS_EXPR ? BINFO_TYPE (binfo) : BINFO_TYPE (d_binfo);
 294
 295   /* Do we need to look in the vtable for the real offset?  */
 296   virtual_access = (v_binfo && fixed_type_p <= 0);
 297
 298   /* Do we need to check for a null pointer?  */
 299   if (want_pointer && !nonnull)
 300     {
 301       /* If we know the conversion will not actually change the value
 302          of EXPR, then we can avoid testing the expression for NULL.
 303          We have to avoid generating a COMPONENT_REF for a base class
 304          field, because other parts of the compiler know that such
 305          expressions are always non-NULL.  */
 306       if (!virtual_access && integer_zerop (offset))
 307         return build_nop (build_pointer_type (target_type), expr);
 308       null_test = error_mark_node;
 309     }
 310
 311   /* Protect against multiple evaluation if necessary.  */
 312   if (TREE_SIDE_EFFECTS (expr) && (null_test || virtual_access))
 313     expr = save_expr (expr);
 314
 315   /* Now that we've saved expr, build the real null test.  */
 316   if (null_test)
 317     {
 318       tree zero = cp_convert (TREE_TYPE (expr), integer_zero_node);
 319       null_test = fold_build2 (NE_EXPR, boolean_type_node,
 320                                expr, zero);
 321     }
 322
 323   /* If this is a simple base reference, express it as a COMPONENT_REF.  */
 324   if (code == PLUS_EXPR && !virtual_access
 325       /* We don't build base fields for empty bases, and they aren't very
 326          interesting to the optimizers anyway.  */
 327       && !has_empty)
 328     {
 329       expr = build_indirect_ref (expr, NULL);
 330       expr = build_simple_base_path (expr, binfo);
 331       if (want_pointer)
 332         expr = build_address (expr);
 333       target_type = TREE_TYPE (expr);
 334       goto out;
 335     }
 336
 337   if (virtual_access)
 338     {
 339       /* Going via virtual base V_BINFO.  We need the static offset
 340          from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
 341          V_BINFO.  That offset is an entry in D_BINFO's vtable.  */
 342       tree v_offset;
 343
 344       if (fixed_type_p < 0 && in_base_initializer)
 345         {
 346           /* In a base member initializer, we cannot rely on the
 347              vtable being set up.  We have to indirect via the
 348              vtt_parm.  */
 349           tree t;
 350
 351           t = TREE_TYPE (TYPE_VFIELD (current_class_type));
 352           t = build_pointer_type (t);
 353           v_offset = convert (t, current_vtt_parm);
 354           v_offset = build_indirect_ref (v_offset, NULL);
 355         }
 356       else
 357         v_offset = build_vfield_ref (build_indirect_ref (expr, NULL),
 358                                      TREE_TYPE (TREE_TYPE (expr)));
 359
 360       v_offset = build2 (PLUS_EXPR, TREE_TYPE (v_offset),
 361                          v_offset,  BINFO_VPTR_FIELD (v_binfo));
 362       v_offset = build1 (NOP_EXPR,
 363                          build_pointer_type (ptrdiff_type_node),
 364                          v_offset);
 365       v_offset = build_indirect_ref (v_offset, NULL);
 366       TREE_CONSTANT (v_offset) = 1;
 367       TREE_INVARIANT (v_offset) = 1;
 368
 369       offset = convert_to_integer (ptrdiff_type_node,
 370                                    size_diffop (offset,
 371                                                 BINFO_OFFSET (v_binfo)));
 372
 373       if (!integer_zerop (offset))
 374         v_offset = build2 (code, ptrdiff_type_node, v_offset, offset);
 375
 376       if (fixed_type_p < 0)
 377         /* Negative fixed_type_p means this is a constructor or destructor;
 378            virtual base layout is fixed in in-charge [cd]tors, but not in
 379            base [cd]tors.  */
 380         offset = build3 (COND_EXPR, ptrdiff_type_node,
 381                          build2 (EQ_EXPR, boolean_type_node,
 382                                  current_in_charge_parm, integer_zero_node),
 383                          v_offset,
 384                          convert_to_integer (ptrdiff_type_node,
 385                                              BINFO_OFFSET (binfo)));
 386       else
 387         offset = v_offset;
 388     }
 389
 390   target_type = cp_build_qualified_type
 391     (target_type, cp_type_quals (TREE_TYPE (TREE_TYPE (expr))));
 392   ptr_target_type = build_pointer_type (target_type);
 393   if (want_pointer)
 394     target_type = ptr_target_type;
 395
 396   expr = build1 (NOP_EXPR, ptr_target_type, expr);
 397
 398   if (!integer_zerop (offset))
 399     expr = build2 (code, ptr_target_type, expr, offset);
 400   else
 401     null_test = NULL;
 402
 403   if (!want_pointer)
 404     expr = build_indirect_ref (expr, NULL);
 405
 406  out:
 407   if (null_test)
 408     expr = fold_build3 (COND_EXPR, target_type, null_test, expr,
 409                         fold_build1 (NOP_EXPR, target_type,
 410                                      integer_zero_node));
 411
 412   return expr;
 413 }
 414
 415 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
 416    Perform a derived-to-base conversion by recursively building up a
 417    sequence of COMPONENT_REFs to the appropriate base fields.  */
 418
 419 static tree
 420 build_simple_base_path (tree expr, tree binfo)
 421 {
 422   tree type = BINFO_TYPE (binfo);
 423   tree d_binfo = BINFO_INHERITANCE_CHAIN (binfo);
 424   tree field;
 425
 426   if (d_binfo == NULL_TREE)
 427     {
 428       tree temp;
 429
 430       gcc_assert (TYPE_MAIN_VARIANT (TREE_TYPE (expr)) == type);
 431
 432       /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
 433          into `(*(a ?  &b : &c)).x', and so on.  A COND_EXPR is only
 434          an lvalue in the frontend; only _DECLs and _REFs are lvalues
 435          in the backend.  */
 436       temp = unary_complex_lvalue (ADDR_EXPR, expr);
 437       if (temp)
 438         expr = build_indirect_ref (temp, NULL);
 439
 440       return expr;
 441     }
 442
 443   /* Recurse.  */
 444   expr = build_simple_base_path (expr, d_binfo);
 445
 446   for (field = TYPE_FIELDS (BINFO_TYPE (d_binfo));
 447        field; field = TREE_CHAIN (field))
 448     /* Is this the base field created by build_base_field?  */
 449     if (TREE_CODE (field) == FIELD_DECL
 450         && DECL_FIELD_IS_BASE (field)
 451         && TREE_TYPE (field) == type)
 452       {
 453         /* We don't use build_class_member_access_expr here, as that
 454            has unnecessary checks, and more importantly results in
 455            recursive calls to dfs_walk_once.  */
 456         int type_quals = cp_type_quals (TREE_TYPE (expr));
 457
 458         expr = build3 (COMPONENT_REF,
 459                        cp_build_qualified_type (type, type_quals),
 460                        expr, field, NULL_TREE);
 461         expr = fold_if_not_in_template (expr);
 462
 463         /* Mark the expression const or volatile, as appropriate.
 464            Even though we've dealt with the type above, we still have
 465            to mark the expression itself.  */
 466         if (type_quals & TYPE_QUAL_CONST)
 467           TREE_READONLY (expr) = 1;
 468         if (type_quals & TYPE_QUAL_VOLATILE)
 469           TREE_THIS_VOLATILE (expr) = 1;
 470
 471         return expr;
 472       }
 473
 474   /* Didn't find the base field?!?  */
 475   gcc_unreachable ();
 476 }
 477
 478 /* Convert OBJECT to the base TYPE.  OBJECT is an expression whose
 479    type is a class type or a pointer to a class type.  In the former
 480    case, TYPE is also a class type; in the latter it is another
 481    pointer type.  If CHECK_ACCESS is true, an error message is emitted
 482    if TYPE is inaccessible.  If OBJECT has pointer type, the value is
 483    assumed to be non-NULL.  */
 484
 485 tree
 486 convert_to_base (tree object, tree type, bool check_access, bool nonnull)
 487 {
 488   tree binfo;
 489   tree object_type;
 490
 491   if (TYPE_PTR_P (TREE_TYPE (object)))
 492     {
 493       object_type = TREE_TYPE (TREE_TYPE (object));
 494       type = TREE_TYPE (type);
 495     }
 496   else
 497     object_type = TREE_TYPE (object);
 498
 499   binfo = lookup_base (object_type, type,
 500                        check_access ? ba_check : ba_unique,
 501                        NULL);
 502   if (!binfo || binfo == error_mark_node)
 503     return error_mark_node;
 504
 505   return build_base_path (PLUS_EXPR, object, binfo, nonnull);
 506 }
 507
 508 /* EXPR is an expression with unqualified class type.  BASE is a base
 509    binfo of that class type.  Returns EXPR, converted to the BASE
 510    type.  This function assumes that EXPR is the most derived class;
 511    therefore virtual bases can be found at their static offsets.  */
 512
 513 tree
 514 convert_to_base_statically (tree expr, tree base)
 515 {
 516   tree expr_type;
 517
 518   expr_type = TREE_TYPE (expr);
 519   if (!SAME_BINFO_TYPE_P (BINFO_TYPE (base), expr_type))
 520     {
 521       tree pointer_type;
 522
 523       pointer_type = build_pointer_type (expr_type);
 524       expr = build_unary_op (ADDR_EXPR, expr, /*noconvert=*/1);
 525       if (!integer_zerop (BINFO_OFFSET (base)))
 526           expr = build2 (PLUS_EXPR, pointer_type, expr,
 527                          build_nop (pointer_type, BINFO_OFFSET (base)));
 528       expr = build_nop (build_pointer_type (BINFO_TYPE (base)), expr);
 529       expr = build1 (INDIRECT_REF, BINFO_TYPE (base), expr);
 530     }
 531
 532   return expr;
 533 }
 534
 535 \f
 536 tree
 537 build_vfield_ref (tree datum, tree type)
 538 {
 539   tree vfield, vcontext;
 540
 541   if (datum == error_mark_node)
 542     return error_mark_node;
 543
 544   /* First, convert to the requested type.  */
 545   if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (datum), type))
 546     datum = convert_to_base (datum, type, /*check_access=*/false,
 547                              /*nonnull=*/true);
 548
 549   /* Second, the requested type may not be the owner of its own vptr.
 550      If not, convert to the base class that owns it.  We cannot use
 551      convert_to_base here, because VCONTEXT may appear more than once
 552      in the inheritance hierarchy of TYPE, and thus direct conversion
 553      between the types may be ambiguous.  Following the path back up
 554      one step at a time via primary bases avoids the problem.  */
 555   vfield = TYPE_VFIELD (type);
 556   vcontext = DECL_CONTEXT (vfield);
 557   while (!same_type_ignoring_top_level_qualifiers_p (vcontext, type))
 558     {
 559       datum = build_simple_base_path (datum, CLASSTYPE_PRIMARY_BINFO (type));
 560       type = TREE_TYPE (datum);
 561     }
 562
 563   return build3 (COMPONENT_REF, TREE_TYPE (vfield), datum, vfield, NULL_TREE);
 564 }
 565
 566 /* Given an object INSTANCE, return an expression which yields the
 567    vtable element corresponding to INDEX.  There are many special
 568    cases for INSTANCE which we take care of here, mainly to avoid
 569    creating extra tree nodes when we don't have to.  */
 570
 571 static tree
 572 build_vtbl_ref_1 (tree instance, tree idx)
 573 {
 574   tree aref;
 575   tree vtbl = NULL_TREE;
 576
 577   /* Try to figure out what a reference refers to, and
 578      access its virtual function table directly.  */
 579
 580   int cdtorp = 0;
 581   tree fixed_type = fixed_type_or_null (instance, NULL, &cdtorp);
 582
 583   tree basetype = non_reference (TREE_TYPE (instance));
 584
 585   if (fixed_type && !cdtorp)
 586     {
 587       tree binfo = lookup_base (fixed_type, basetype,
 588                                 ba_unique | ba_quiet, NULL);
 589       if (binfo)
 590         vtbl = unshare_expr (BINFO_VTABLE (binfo));
 591     }
 592
 593   if (!vtbl)
 594     vtbl = build_vfield_ref (instance, basetype);
 595
 596   assemble_external (vtbl);
 597
 598   aref = build_array_ref (vtbl, idx);
 599   TREE_CONSTANT (aref) |= TREE_CONSTANT (vtbl) && TREE_CONSTANT (idx);
 600   TREE_INVARIANT (aref) = TREE_CONSTANT (aref);
 601
 602   return aref;
 603 }
 604
 605 tree
 606 build_vtbl_ref (tree instance, tree idx)
 607 {
 608   tree aref = build_vtbl_ref_1 (instance, idx);
 609
 610   return aref;
 611 }
 612
 613 /* Given a stable object pointer INSTANCE_PTR, return an expression which
 614    yields a function pointer corresponding to vtable element INDEX.  */
 615
 616 tree
 617 build_vfn_ref (tree instance_ptr, tree idx)
 618 {
 619   tree aref;
 620
 621   aref = build_vtbl_ref_1 (build_indirect_ref (instance_ptr, 0), idx);
 622
 623   /* When using function descriptors, the address of the
 624      vtable entry is treated as a function pointer.  */
 625   if (TARGET_VTABLE_USES_DESCRIPTORS)
 626     aref = build1 (NOP_EXPR, TREE_TYPE (aref),
 627                    build_unary_op (ADDR_EXPR, aref, /*noconvert=*/1));
 628
 629   /* Remember this as a method reference, for later devirtualization.  */
 630   aref = build3 (OBJ_TYPE_REF, TREE_TYPE (aref), aref, instance_ptr, idx);
 631
 632   return aref;
 633 }
 634
 635 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
 636    for the given TYPE.  */
 637
 638 static tree
 639 get_vtable_name (tree type)
 640 {
 641   return mangle_vtbl_for_type (type);
 642 }
 643
 644 /* DECL is an entity associated with TYPE, like a virtual table or an
 645    implicitly generated constructor.  Determine whether or not DECL
 646    should have external or internal linkage at the object file
 647    level.  This routine does not deal with COMDAT linkage and other
 648    similar complexities; it simply sets TREE_PUBLIC if it possible for
 649    entities in other translation units to contain copies of DECL, in
 650    the abstract.  */
 651
 652 void
 653 set_linkage_according_to_type (tree type, tree decl)
 654 {
 655   /* If TYPE involves a local class in a function with internal
 656      linkage, then DECL should have internal linkage too.  Other local
 657      classes have no linkage -- but if their containing functions
 658      have external linkage, it makes sense for DECL to have external
 659      linkage too.  That will allow template definitions to be merged,
 660      for example.  */
 661   if (no_linkage_check (type, /*relaxed_p=*/true))
 662     {
 663       TREE_PUBLIC (decl) = 0;
 664       DECL_INTERFACE_KNOWN (decl) = 1;
 665     }
 666   else
 667     TREE_PUBLIC (decl) = 1;
 668 }
 669
 670 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
 671    (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
 672    Use NAME for the name of the vtable, and VTABLE_TYPE for its type.  */
 673
 674 static tree
 675 build_vtable (tree class_type, tree name, tree vtable_type)
 676 {
 677   tree decl;
 678
 679   decl = build_lang_decl (VAR_DECL, name, vtable_type);
 680   /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
 681      now to avoid confusion in mangle_decl.  */
 682   SET_DECL_ASSEMBLER_NAME (decl, name);
 683   DECL_CONTEXT (decl) = class_type;
 684   DECL_ARTIFICIAL (decl) = 1;
 685   TREE_STATIC (decl) = 1;
 686   TREE_READONLY (decl) = 1;
 687   DECL_VIRTUAL_P (decl) = 1;
 688   DECL_ALIGN (decl) = TARGET_VTABLE_ENTRY_ALIGN;
 689   DECL_VTABLE_OR_VTT_P (decl) = 1;
 690   /* At one time the vtable info was grabbed 2 words at a time.  This
 691      fails on sparc unless you have 8-byte alignment.  (tiemann) */
 692   DECL_ALIGN (decl) = MAX (TYPE_ALIGN (double_type_node),
 693                            DECL_ALIGN (decl));
 694   set_linkage_according_to_type (class_type, decl);
 695   /* The vtable has not been defined -- yet.  */
 696   DECL_EXTERNAL (decl) = 1;
 697   DECL_NOT_REALLY_EXTERN (decl) = 1;
 698
 699   /* Mark the VAR_DECL node representing the vtable itself as a
 700      "gratuitous" one, thereby forcing dwarfout.c to ignore it.  It
 701      is rather important that such things be ignored because any
 702      effort to actually generate DWARF for them will run into
 703      trouble when/if we encounter code like:
 704
 705      #pragma interface
 706      struct S { virtual void member (); };
 707
 708      because the artificial declaration of the vtable itself (as
 709      manufactured by the g++ front end) will say that the vtable is
 710      a static member of `S' but only *after* the debug output for
 711      the definition of `S' has already been output.  This causes
 712      grief because the DWARF entry for the definition of the vtable
 713      will try to refer back to an earlier *declaration* of the
 714      vtable as a static member of `S' and there won't be one.  We
 715      might be able to arrange to have the "vtable static member"
 716      attached to the member list for `S' before the debug info for
 717      `S' get written (which would solve the problem) but that would
 718      require more intrusive changes to the g++ front end.  */
 719   DECL_IGNORED_P (decl) = 1;
 720
 721   return decl;
 722 }
 723
 724 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
 725    or even complete.  If this does not exist, create it.  If COMPLETE is
 726    nonzero, then complete the definition of it -- that will render it
 727    impossible to actually build the vtable, but is useful to get at those
 728    which are known to exist in the runtime.  */
 729
 730 tree
 731 get_vtable_decl (tree type, int complete)
 732 {
 733   tree decl;
 734
 735   if (CLASSTYPE_VTABLES (type))
 736     return CLASSTYPE_VTABLES (type);
 737
 738   decl = build_vtable (type, get_vtable_name (type), vtbl_type_node);
 739   CLASSTYPE_VTABLES (type) = decl;
 740
 741   if (complete)
 742     {
 743       DECL_EXTERNAL (decl) = 1;
 744       finish_decl (decl, NULL_TREE, NULL_TREE);
 745     }
 746
 747   return decl;
 748 }
 749
 750 /* Build the primary virtual function table for TYPE.  If BINFO is
 751    non-NULL, build the vtable starting with the initial approximation
 752    that it is the same as the one which is the head of the association
 753    list.  Returns a nonzero value if a new vtable is actually
 754    created.  */
 755
 756 static int
 757 build_primary_vtable (tree binfo, tree type)
 758 {
 759   tree decl;
 760   tree virtuals;
 761
 762   decl = get_vtable_decl (type, /*complete=*/0);
 763
 764   if (binfo)
 765     {
 766       if (BINFO_NEW_VTABLE_MARKED (binfo))
 767         /* We have already created a vtable for this base, so there's
 768            no need to do it again.  */
 769         return 0;
 770
 771       virtuals = copy_list (BINFO_VIRTUALS (binfo));
 772       TREE_TYPE (decl) = TREE_TYPE (get_vtbl_decl_for_binfo (binfo));
 773       DECL_SIZE (decl) = TYPE_SIZE (TREE_TYPE (decl));
 774       DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (TREE_TYPE (decl));
 775     }
 776   else
 777     {
 778       gcc_assert (TREE_TYPE (decl) == vtbl_type_node);
 779       virtuals = NULL_TREE;
 780     }
 781
 782 #ifdef GATHER_STATISTICS
 783   n_vtables += 1;
 784   n_vtable_elems += list_length (virtuals);
 785 #endif
 786
 787   /* Initialize the association list for this type, based
 788      on our first approximation.  */
 789   BINFO_VTABLE (TYPE_BINFO (type)) = decl;
 790   BINFO_VIRTUALS (TYPE_BINFO (type)) = virtuals;
 791   SET_BINFO_NEW_VTABLE_MARKED (TYPE_BINFO (type));
 792   return 1;
 793 }
 794
 795 /* Give BINFO a new virtual function table which is initialized
 796    with a skeleton-copy of its original initialization.  The only
 797    entry that changes is the `delta' entry, so we can really
 798    share a lot of structure.
 799
 800    FOR_TYPE is the most derived type which caused this table to
 801    be needed.
 802
 803    Returns nonzero if we haven't met BINFO before.
 804
 805    The order in which vtables are built (by calling this function) for
 806    an object must remain the same, otherwise a binary incompatibility
 807    can result.  */
 808
 809 static int
 810 build_secondary_vtable (tree binfo)
 811 {
 812   if (BINFO_NEW_VTABLE_MARKED (binfo))
 813     /* We already created a vtable for this base.  There's no need to
 814        do it again.  */
 815     return 0;
 816
 817   /* Remember that we've created a vtable for this BINFO, so that we
 818      don't try to do so again.  */
 819   SET_BINFO_NEW_VTABLE_MARKED (binfo);
 820
 821   /* Make fresh virtual list, so we can smash it later.  */
 822   BINFO_VIRTUALS (binfo) = copy_list (BINFO_VIRTUALS (binfo));
 823
 824   /* Secondary vtables are laid out as part of the same structure as
 825      the primary vtable.  */
 826   BINFO_VTABLE (binfo) = NULL_TREE;
 827   return 1;
 828 }
 829
 830 /* Create a new vtable for BINFO which is the hierarchy dominated by
 831    T. Return nonzero if we actually created a new vtable.  */
 832
 833 static int
 834 make_new_vtable (tree t, tree binfo)
 835 {
 836   if (binfo == TYPE_BINFO (t))
 837     /* In this case, it is *type*'s vtable we are modifying.  We start
 838        with the approximation that its vtable is that of the
 839        immediate base class.  */
 840     return build_primary_vtable (binfo, t);
 841   else
 842     /* This is our very own copy of `basetype' to play with.  Later,
 843        we will fill in all the virtual functions that override the
 844        virtual functions in these base classes which are not defined
 845        by the current type.  */
 846     return build_secondary_vtable (binfo);
 847 }
 848
 849 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
 850    (which is in the hierarchy dominated by T) list FNDECL as its
 851    BV_FN.  DELTA is the required constant adjustment from the `this'
 852    pointer where the vtable entry appears to the `this' required when
 853    the function is actually called.  */
 854
 855 static void
 856 modify_vtable_entry (tree t,
 857                      tree binfo,
 858                      tree fndecl,
 859                      tree delta,
 860                      tree *virtuals)
 861 {
 862   tree v;
 863
 864   v = *virtuals;
 865
 866   if (fndecl != BV_FN (v)
 867       || !tree_int_cst_equal (delta, BV_DELTA (v)))
 868     {
 869       /* We need a new vtable for BINFO.  */
 870       if (make_new_vtable (t, binfo))
 871         {
 872           /* If we really did make a new vtable, we also made a copy
 873              of the BINFO_VIRTUALS list.  Now, we have to find the
 874              corresponding entry in that list.  */
 875           *virtuals = BINFO_VIRTUALS (binfo);
 876           while (BV_FN (*virtuals) != BV_FN (v))
 877             *virtuals = TREE_CHAIN (*virtuals);
 878           v = *virtuals;
 879         }
 880
 881       BV_DELTA (v) = delta;
 882       BV_VCALL_INDEX (v) = NULL_TREE;
 883       BV_FN (v) = fndecl;
 884     }
 885 }
 886
 887 \f
 888 /* Add method METHOD to class TYPE.  If USING_DECL is non-null, it is
 889    the USING_DECL naming METHOD.  Returns true if the method could be
 890    added to the method vec.  */
 891
 892 bool
 893 add_method (tree type, tree method, tree using_decl)
 894 {
 895   unsigned slot;
 896   tree overload;
 897   bool template_conv_p = false;
 898   bool conv_p;
 899   VEC(tree,gc) *method_vec;
 900   bool complete_p;
 901   bool insert_p = false;
 902   tree current_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   /* Constructors and destructors go in special slots.  */
 928   if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (method))
 929     slot = CLASSTYPE_CONSTRUCTOR_SLOT;
 930   else if (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (method))
 931     {
 932       slot = CLASSTYPE_DESTRUCTOR_SLOT;
 933
 934       if (TYPE_FOR_JAVA (type))
 935         {
 936           if (!DECL_ARTIFICIAL (method))
 937             error ("Java class %qT cannot have a destructor", type);
 938           else if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
 939             error ("Java class %qT cannot have an implicit non-trivial "
 940                    "destructor",
 941                    type);
 942         }
 943     }
 944   else
 945     {
 946       tree m;
 947
 948       insert_p = true;
 949       /* See if we already have an entry with this name.  */
 950       for (slot = CLASSTYPE_FIRST_CONVERSION_SLOT;
 951            VEC_iterate (tree, method_vec, slot, m);
 952            ++slot)
 953         {
 954           m = OVL_CURRENT (m);
 955           if (template_conv_p)
 956             {
 957               if (TREE_CODE (m) == TEMPLATE_DECL
 958                   && DECL_TEMPLATE_CONV_FN_P (m))
 959                 insert_p = false;
 960               break;
 961             }
 962           if (conv_p && !DECL_CONV_FN_P (m))
 963             break;
 964           if (DECL_NAME (m) == DECL_NAME (method))
 965             {
 966               insert_p = false;
 967               break;
 968             }
 969           if (complete_p
 970               && !DECL_CONV_FN_P (m)
 971               && DECL_NAME (m) > DECL_NAME (method))
 972             break;
 973         }
 974     }
 975   current_fns = insert_p ? NULL_TREE : VEC_index (tree, method_vec, slot);
 976
 977   if (processing_template_decl)
 978     /* TYPE is a template class.  Don't issue any errors now; wait
 979        until instantiation time to complain.  */
 980     ;
 981   else
 982     {
 983       tree fns;
 984
 985       /* Check to see if we've already got this method.  */
 986       for (fns = current_fns; fns; fns = OVL_NEXT (fns))
 987         {
 988           tree fn = OVL_CURRENT (fns);
 989           tree fn_type;
 990           tree method_type;
 991           tree parms1;
 992           tree parms2;
 993
 994           if (TREE_CODE (fn) != TREE_CODE (method))
 995             continue;
 996
 997           /* [over.load] Member function declarations with the
 998              same name and the same parameter types cannot be
 999              overloaded if any of them is a static member
1000              function declaration.
1001
1002              [namespace.udecl] When a using-declaration brings names
1003              from a base class into a derived class scope, member
1004              functions in the derived class override and/or hide member
1005              functions with the same name and parameter types in a base
1006              class (rather than conflicting).  */
1007           fn_type = TREE_TYPE (fn);
1008           method_type = TREE_TYPE (method);
1009           parms1 = TYPE_ARG_TYPES (fn_type);
1010           parms2 = TYPE_ARG_TYPES (method_type);
1011
1012           /* Compare the quals on the 'this' parm.  Don't compare
1013              the whole types, as used functions are treated as
1014              coming from the using class in overload resolution.  */
1015           if (! DECL_STATIC_FUNCTION_P (fn)
1016               && ! DECL_STATIC_FUNCTION_P (method)
1017               && (TYPE_QUALS (TREE_TYPE (TREE_VALUE (parms1)))
1018                   != TYPE_QUALS (TREE_TYPE (TREE_VALUE (parms2)))))
1019             continue;
1020
1021           /* For templates, the return type and template parameters
1022              must be identical.  */
1023           if (TREE_CODE (fn) == TEMPLATE_DECL
1024               && (!same_type_p (TREE_TYPE (fn_type),
1025                                 TREE_TYPE (method_type))
1026                   || !comp_template_parms (DECL_TEMPLATE_PARMS (fn),
1027                                            DECL_TEMPLATE_PARMS (method))))
1028             continue;
1029
1030           if (! DECL_STATIC_FUNCTION_P (fn))
1031             parms1 = TREE_CHAIN (parms1);
1032           if (! DECL_STATIC_FUNCTION_P (method))
1033             parms2 = TREE_CHAIN (parms2);
1034
1035           if (compparms (parms1, parms2)
1036               && (!DECL_CONV_FN_P (fn)
1037                   || same_type_p (TREE_TYPE (fn_type),
1038                                   TREE_TYPE (method_type))))
1039             {
1040               if (using_decl)
1041                 {
1042                   if (DECL_CONTEXT (fn) == type)
1043                     /* Defer to the local function.  */
1044                     return false;
1045                   if (DECL_CONTEXT (fn) == DECL_CONTEXT (method))
1046                     error ("repeated using declaration %q+D", using_decl);
1047                   else
1048                     error ("using declaration %q+D conflicts with a previous using declaration",
1049                            using_decl);
1050                 }
1051               else
1052                 {
1053                   error ("%q+#D cannot be overloaded", method);
1054                   error ("with %q+#D", fn);
1055                 }
1056
1057               /* We don't call duplicate_decls here to merge the
1058                  declarations because that will confuse things if the
1059                  methods have inline definitions.  In particular, we
1060                  will crash while processing the definitions.  */
1061               return false;
1062             }
1063         }
1064     }
1065
1066   /* A class should never have more than one destructor.  */
1067   if (current_fns && DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (method))
1068     return false;
1069
1070   /* Add the new binding.  */
1071   overload = build_overload (method, current_fns);
1072
1073   if (conv_p)
1074     TYPE_HAS_CONVERSION (type) = 1;
1075   else if (slot >= CLASSTYPE_FIRST_CONVERSION_SLOT && !complete_p)
1076     push_class_level_binding (DECL_NAME (method), overload);
1077
1078   if (insert_p)
1079     {
1080       /* We only expect to add few methods in the COMPLETE_P case, so
1081          just make room for one more method in that case.  */
1082       if (VEC_reserve (tree, gc, method_vec, complete_p ? -1 : 1))
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);
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     }
1274 }
1275
1276 /* Determine all the primary bases within T.  Sets BINFO_PRIMARY_BASE_P for
1277    those that are primaries.  Sets BINFO_LOST_PRIMARY_P for those
1278    that have had a nearly-empty virtual primary base stolen by some
1279    other base in the hierarchy.  Determines CLASSTYPE_PRIMARY_BASE for
1280    T.  */
1281
1282 static void
1283 determine_primary_bases (tree t)
1284 {
1285   unsigned i;
1286   tree primary = NULL_TREE;
1287   tree type_binfo = TYPE_BINFO (t);
1288   tree base_binfo;
1289
1290   /* Determine the primary bases of our bases.  */
1291   for (base_binfo = TREE_CHAIN (type_binfo); base_binfo;
1292        base_binfo = TREE_CHAIN (base_binfo))
1293     {
1294       tree primary = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (base_binfo));
1295
1296       /* See if we're the non-virtual primary of our inheritance
1297          chain.  */
1298       if (!BINFO_VIRTUAL_P (base_binfo))
1299         {
1300           tree parent = BINFO_INHERITANCE_CHAIN (base_binfo);
1301           tree parent_primary = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (parent));
1302
1303           if (parent_primary
1304               && SAME_BINFO_TYPE_P (BINFO_TYPE (base_binfo),
1305                                     BINFO_TYPE (parent_primary)))
1306             /* We are the primary binfo.  */
1307             BINFO_PRIMARY_P (base_binfo) = 1;
1308         }
1309       /* Determine if we have a virtual primary base, and mark it so.
1310        */
1311       if (primary && BINFO_VIRTUAL_P (primary))
1312         {
1313           tree this_primary = copied_binfo (primary, base_binfo);
1314
1315           if (BINFO_PRIMARY_P (this_primary))
1316             /* Someone already claimed this base.  */
1317             BINFO_LOST_PRIMARY_P (base_binfo) = 1;
1318           else
1319             {
1320               tree delta;
1321
1322               BINFO_PRIMARY_P (this_primary) = 1;
1323               BINFO_INHERITANCE_CHAIN (this_primary) = base_binfo;
1324
1325               /* A virtual binfo might have been copied from within
1326                  another hierarchy. As we're about to use it as a
1327                  primary base, make sure the offsets match.  */
1328               delta = size_diffop (convert (ssizetype,
1329                                             BINFO_OFFSET (base_binfo)),
1330                                    convert (ssizetype,
1331                                             BINFO_OFFSET (this_primary)));
1332
1333               propagate_binfo_offsets (this_primary, delta);
1334             }
1335         }
1336     }
1337
1338   /* First look for a dynamic direct non-virtual base.  */
1339   for (i = 0; BINFO_BASE_ITERATE (type_binfo, i, base_binfo); i++)
1340     {
1341       tree basetype = BINFO_TYPE (base_binfo);
1342
1343       if (TYPE_CONTAINS_VPTR_P (basetype) && !BINFO_VIRTUAL_P (base_binfo))
1344         {
1345           primary = base_binfo;
1346           goto found;
1347         }
1348     }
1349
1350   /* A "nearly-empty" virtual base class can be the primary base
1351      class, if no non-virtual polymorphic base can be found.  Look for
1352      a nearly-empty virtual dynamic base that is not already a primary
1353      base of something in the hierarchy.  If there is no such base,
1354      just pick the first nearly-empty virtual base.  */
1355
1356   for (base_binfo = TREE_CHAIN (type_binfo); base_binfo;
1357        base_binfo = TREE_CHAIN (base_binfo))
1358     if (BINFO_VIRTUAL_P (base_binfo)
1359         && CLASSTYPE_NEARLY_EMPTY_P (BINFO_TYPE (base_binfo)))
1360       {
1361         if (!BINFO_PRIMARY_P (base_binfo))
1362           {
1363             /* Found one that is not primary.  */
1364             primary = base_binfo;
1365             goto found;
1366           }
1367         else if (!primary)
1368           /* Remember the first candidate.  */
1369           primary = base_binfo;
1370       }
1371
1372  found:
1373   /* If we've got a primary base, use it.  */
1374   if (primary)
1375     {
1376       tree basetype = BINFO_TYPE (primary);
1377
1378       CLASSTYPE_PRIMARY_BINFO (t) = primary;
1379       if (BINFO_PRIMARY_P (primary))
1380         /* We are stealing a primary base.  */
1381         BINFO_LOST_PRIMARY_P (BINFO_INHERITANCE_CHAIN (primary)) = 1;
1382       BINFO_PRIMARY_P (primary) = 1;
1383       if (BINFO_VIRTUAL_P (primary))
1384         {
1385           tree delta;
1386
1387           BINFO_INHERITANCE_CHAIN (primary) = type_binfo;
1388           /* A virtual binfo might have been copied from within
1389              another hierarchy. As we're about to use it as a primary
1390              base, make sure the offsets match.  */
1391           delta = size_diffop (ssize_int (0),
1392                                convert (ssizetype, BINFO_OFFSET (primary)));
1393
1394           propagate_binfo_offsets (primary, delta);
1395         }
1396
1397       primary = TYPE_BINFO (basetype);
1398
1399       TYPE_VFIELD (t) = TYPE_VFIELD (basetype);
1400       BINFO_VTABLE (type_binfo) = BINFO_VTABLE (primary);
1401       BINFO_VIRTUALS (type_binfo) = BINFO_VIRTUALS (primary);
1402     }
1403 }
1404 \f
1405 /* Set memoizing fields and bits of T (and its variants) for later
1406    use.  */
1407
1408 static void
1409 finish_struct_bits (tree t)
1410 {
1411   tree variants;
1412
1413   /* Fix up variants (if any).  */
1414   for (variants = TYPE_NEXT_VARIANT (t);
1415        variants;
1416        variants = TYPE_NEXT_VARIANT (variants))
1417     {
1418       /* These fields are in the _TYPE part of the node, not in
1419          the TYPE_LANG_SPECIFIC component, so they are not shared.  */
1420       TYPE_HAS_CONSTRUCTOR (variants) = TYPE_HAS_CONSTRUCTOR (t);
1421       TYPE_NEEDS_CONSTRUCTING (variants) = TYPE_NEEDS_CONSTRUCTING (t);
1422       TYPE_HAS_NONTRIVIAL_DESTRUCTOR (variants)
1423         = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t);
1424
1425       TYPE_POLYMORPHIC_P (variants) = TYPE_POLYMORPHIC_P (t);
1426
1427       TYPE_BINFO (variants) = TYPE_BINFO (t);
1428
1429       /* Copy whatever these are holding today.  */
1430       TYPE_VFIELD (variants) = TYPE_VFIELD (t);
1431       TYPE_METHODS (variants) = TYPE_METHODS (t);
1432       TYPE_FIELDS (variants) = TYPE_FIELDS (t);
1433       TYPE_SIZE (variants) = TYPE_SIZE (t);
1434       TYPE_SIZE_UNIT (variants) = TYPE_SIZE_UNIT (t);
1435     }
1436
1437   if (BINFO_N_BASE_BINFOS (TYPE_BINFO (t)) && TYPE_POLYMORPHIC_P (t))
1438     /* For a class w/o baseclasses, 'finish_struct' has set
1439        CLASSTYPE_PURE_VIRTUALS correctly (by definition).
1440        Similarly for a class whose base classes do not have vtables.
1441        When neither of these is true, we might have removed abstract
1442        virtuals (by providing a definition), added some (by declaring
1443        new ones), or redeclared ones from a base class.  We need to
1444        recalculate what's really an abstract virtual at this point (by
1445        looking in the vtables).  */
1446     get_pure_virtuals (t);
1447
1448   /* If this type has a copy constructor or a destructor, force its
1449      mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
1450      nonzero.  This will cause it to be passed by invisible reference
1451      and prevent it from being returned in a register.  */
1452   if (! TYPE_HAS_TRIVIAL_INIT_REF (t) || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t))
1453     {
1454       tree variants;
1455       DECL_MODE (TYPE_MAIN_DECL (t)) = BLKmode;
1456       for (variants = t; variants; variants = TYPE_NEXT_VARIANT (variants))
1457         {
1458           TYPE_MODE (variants) = BLKmode;
1459           TREE_ADDRESSABLE (variants) = 1;
1460         }
1461     }
1462 }
1463
1464 /* Issue warnings about T having private constructors, but no friends,
1465    and so forth.
1466
1467    HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
1468    static members.  HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
1469    non-private static member functions.  */
1470
1471 static void
1472 maybe_warn_about_overly_private_class (tree t)
1473 {
1474   int has_member_fn = 0;
1475   int has_nonprivate_method = 0;
1476   tree fn;
1477
1478   if (!warn_ctor_dtor_privacy
1479       /* If the class has friends, those entities might create and
1480          access instances, so we should not warn.  */
1481       || (CLASSTYPE_FRIEND_CLASSES (t)
1482           || DECL_FRIENDLIST (TYPE_MAIN_DECL (t)))
1483       /* We will have warned when the template was declared; there's
1484          no need to warn on every instantiation.  */
1485       || CLASSTYPE_TEMPLATE_INSTANTIATION (t))
1486     /* There's no reason to even consider warning about this
1487        class.  */
1488     return;
1489
1490   /* We only issue one warning, if more than one applies, because
1491      otherwise, on code like:
1492
1493      class A {
1494        // Oops - forgot `public:'
1495        A();
1496        A(const A&);
1497        ~A();
1498      };
1499
1500      we warn several times about essentially the same problem.  */
1501
1502   /* Check to see if all (non-constructor, non-destructor) member
1503      functions are private.  (Since there are no friends or
1504      non-private statics, we can't ever call any of the private member
1505      functions.)  */
1506   for (fn = TYPE_METHODS (t); fn; fn = TREE_CHAIN (fn))
1507     /* We're not interested in compiler-generated methods; they don't
1508        provide any way to call private members.  */
1509     if (!DECL_ARTIFICIAL (fn))
1510       {
1511         if (!TREE_PRIVATE (fn))
1512           {
1513             if (DECL_STATIC_FUNCTION_P (fn))
1514               /* A non-private static member function is just like a
1515                  friend; it can create and invoke private member
1516                  functions, and be accessed without a class
1517                  instance.  */
1518               return;
1519
1520             has_nonprivate_method = 1;
1521             /* Keep searching for a static member function.  */
1522           }
1523         else if (!DECL_CONSTRUCTOR_P (fn) && !DECL_DESTRUCTOR_P (fn))
1524           has_member_fn = 1;
1525       }
1526
1527   if (!has_nonprivate_method && has_member_fn)
1528     {
1529       /* There are no non-private methods, and there's at least one
1530          private member function that isn't a constructor or
1531          destructor.  (If all the private members are
1532          constructors/destructors we want to use the code below that
1533          issues error messages specifically referring to
1534          constructors/destructors.)  */
1535       unsigned i;
1536       tree binfo = TYPE_BINFO (t);
1537
1538       for (i = 0; i != BINFO_N_BASE_BINFOS (binfo); i++)
1539         if (BINFO_BASE_ACCESS (binfo, i) != access_private_node)
1540           {
1541             has_nonprivate_method = 1;
1542             break;
1543           }
1544       if (!has_nonprivate_method)
1545         {
1546           warning (OPT_Wctor_dtor_privacy,
1547                    "all member functions in class %qT are private", t);
1548           return;
1549         }
1550     }
1551
1552   /* Even if some of the member functions are non-private, the class
1553      won't be useful for much if all the constructors or destructors
1554      are private: such an object can never be created or destroyed.  */
1555   fn = CLASSTYPE_DESTRUCTORS (t);
1556   if (fn && TREE_PRIVATE (fn))
1557     {
1558       warning (OPT_Wctor_dtor_privacy,
1559                "%q#T only defines a private destructor and has no friends",
1560                t);
1561       return;
1562     }
1563
1564   if (TYPE_HAS_CONSTRUCTOR (t)
1565       /* Implicitly generated constructors are always public.  */
1566       && (!CLASSTYPE_LAZY_DEFAULT_CTOR (t)
1567           || !CLASSTYPE_LAZY_COPY_CTOR (t)))
1568     {
1569       int nonprivate_ctor = 0;
1570
1571       /* If a non-template class does not define a copy
1572          constructor, one is defined for it, enabling it to avoid
1573          this warning.  For a template class, this does not
1574          happen, and so we would normally get a warning on:
1575
1576            template <class T> class C { private: C(); };
1577
1578          To avoid this asymmetry, we check TYPE_HAS_INIT_REF.  All
1579          complete non-template or fully instantiated classes have this
1580          flag set.  */
1581       if (!TYPE_HAS_INIT_REF (t))
1582         nonprivate_ctor = 1;
1583       else
1584         for (fn = CLASSTYPE_CONSTRUCTORS (t); fn; fn = OVL_NEXT (fn))
1585           {
1586             tree ctor = OVL_CURRENT (fn);
1587             /* Ideally, we wouldn't count copy constructors (or, in
1588                fact, any constructor that takes an argument of the
1589                class type as a parameter) because such things cannot
1590                be used to construct an instance of the class unless
1591                you already have one.  But, for now at least, we're
1592                more generous.  */
1593             if (! TREE_PRIVATE (ctor))
1594               {
1595                 nonprivate_ctor = 1;
1596                 break;
1597               }
1598           }
1599
1600       if (nonprivate_ctor == 0)
1601         {
1602           warning (OPT_Wctor_dtor_privacy,
1603                    "%q#T only defines private constructors and has no friends",
1604                    t);
1605           return;
1606         }
1607     }
1608 }
1609
1610 static struct {
1611   gt_pointer_operator new_value;
1612   void *cookie;
1613 } resort_data;
1614
1615 /* Comparison function to compare two TYPE_METHOD_VEC entries by name.  */
1616
1617 static int
1618 method_name_cmp (const void* m1_p, const void* m2_p)
1619 {
1620   const tree *const m1 = (const tree *) m1_p;
1621   const tree *const m2 = (const tree *) m2_p;
1622
1623   if (*m1 == NULL_TREE && *m2 == NULL_TREE)
1624     return 0;
1625   if (*m1 == NULL_TREE)
1626     return -1;
1627   if (*m2 == NULL_TREE)
1628     return 1;
1629   if (DECL_NAME (OVL_CURRENT (*m1)) < DECL_NAME (OVL_CURRENT (*m2)))
1630     return -1;
1631   return 1;
1632 }
1633
1634 /* This routine compares two fields like method_name_cmp but using the
1635    pointer operator in resort_field_decl_data.  */
1636
1637 static int
1638 resort_method_name_cmp (const void* m1_p, const void* m2_p)
1639 {
1640   const tree *const m1 = (const tree *) m1_p;
1641   const tree *const m2 = (const tree *) m2_p;
1642   if (*m1 == NULL_TREE && *m2 == NULL_TREE)
1643     return 0;
1644   if (*m1 == NULL_TREE)
1645     return -1;
1646   if (*m2 == NULL_TREE)
1647     return 1;
1648   {
1649     tree d1 = DECL_NAME (OVL_CURRENT (*m1));
1650     tree d2 = DECL_NAME (OVL_CURRENT (*m2));
1651     resort_data.new_value (&d1, resort_data.cookie);
1652     resort_data.new_value (&d2, resort_data.cookie);
1653     if (d1 < d2)
1654       return -1;
1655   }
1656   return 1;
1657 }
1658
1659 /* Resort TYPE_METHOD_VEC because pointers have been reordered.  */
1660
1661 void
1662 resort_type_method_vec (void* obj,
1663                         void* orig_obj ATTRIBUTE_UNUSED ,
1664                         gt_pointer_operator new_value,
1665                         void* cookie)
1666 {
1667   VEC(tree,gc) *method_vec = (VEC(tree,gc) *) obj;
1668   int len = VEC_length (tree, method_vec);
1669   size_t slot;
1670   tree fn;
1671
1672   /* The type conversion ops have to live at the front of the vec, so we
1673      can't sort them.  */
1674   for (slot = CLASSTYPE_FIRST_CONVERSION_SLOT;
1675        VEC_iterate (tree, method_vec, slot, fn);
1676        ++slot)
1677     if (!DECL_CONV_FN_P (OVL_CURRENT (fn)))
1678       break;
1679
1680   if (len - slot > 1)
1681     {
1682       resort_data.new_value = new_value;
1683       resort_data.cookie = cookie;
1684       qsort (VEC_address (tree, method_vec) + slot, len - slot, sizeof (tree),
1685              resort_method_name_cmp);
1686     }
1687 }
1688
1689 /* Warn about duplicate methods in fn_fields.
1690
1691    Sort methods that are not special (i.e., constructors, destructors,
1692    and type conversion operators) so that we can find them faster in
1693    search.  */
1694
1695 static void
1696 finish_struct_methods (tree t)
1697 {
1698   tree fn_fields;
1699   VEC(tree,gc) *method_vec;
1700   int slot, len;
1701
1702   method_vec = CLASSTYPE_METHOD_VEC (t);
1703   if (!method_vec)
1704     return;
1705
1706   len = VEC_length (tree, method_vec);
1707
1708   /* Clear DECL_IN_AGGR_P for all functions.  */
1709   for (fn_fields = TYPE_METHODS (t); fn_fields;
1710        fn_fields = TREE_CHAIN (fn_fields))
1711     DECL_IN_AGGR_P (fn_fields) = 0;
1712
1713   /* Issue warnings about private constructors and such.  If there are
1714      no methods, then some public defaults are generated.  */
1715   maybe_warn_about_overly_private_class (t);
1716
1717   /* The type conversion ops have to live at the front of the vec, so we
1718      can't sort them.  */
1719   for (slot = CLASSTYPE_FIRST_CONVERSION_SLOT;
1720        VEC_iterate (tree, method_vec, slot, fn_fields);
1721        ++slot)
1722     if (!DECL_CONV_FN_P (OVL_CURRENT (fn_fields)))
1723       break;
1724   if (len - slot > 1)
1725     qsort (VEC_address (tree, method_vec) + slot,
1726            len-slot, sizeof (tree), method_name_cmp);
1727 }
1728
1729 /* Make BINFO's vtable have N entries, including RTTI entries,
1730    vbase and vcall offsets, etc.  Set its type and call the backend
1731    to lay it out.  */
1732
1733 static void
1734 layout_vtable_decl (tree binfo, int n)
1735 {
1736   tree atype;
1737   tree vtable;
1738
1739   atype = build_cplus_array_type (vtable_entry_type,
1740                                   build_index_type (size_int (n - 1)));
1741   layout_type (atype);
1742
1743   /* We may have to grow the vtable.  */
1744   vtable = get_vtbl_decl_for_binfo (binfo);
1745   if (!same_type_p (TREE_TYPE (vtable), atype))
1746     {
1747       TREE_TYPE (vtable) = atype;
1748       DECL_SIZE (vtable) = DECL_SIZE_UNIT (vtable) = NULL_TREE;
1749       layout_decl (vtable, 0);
1750     }
1751 }
1752
1753 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
1754    have the same signature.  */
1755
1756 int
1757 same_signature_p (tree fndecl, tree base_fndecl)
1758 {
1759   /* One destructor overrides another if they are the same kind of
1760      destructor.  */
1761   if (DECL_DESTRUCTOR_P (base_fndecl) && DECL_DESTRUCTOR_P (fndecl)
1762       && special_function_p (base_fndecl) == special_function_p (fndecl))
1763     return 1;
1764   /* But a non-destructor never overrides a destructor, nor vice
1765      versa, nor do different kinds of destructors override
1766      one-another.  For example, a complete object destructor does not
1767      override a deleting destructor.  */
1768   if (DECL_DESTRUCTOR_P (base_fndecl) || DECL_DESTRUCTOR_P (fndecl))
1769     return 0;
1770
1771   if (DECL_NAME (fndecl) == DECL_NAME (base_fndecl)
1772       || (DECL_CONV_FN_P (fndecl)
1773           && DECL_CONV_FN_P (base_fndecl)
1774           && same_type_p (DECL_CONV_FN_TYPE (fndecl),
1775                           DECL_CONV_FN_TYPE (base_fndecl))))
1776     {
1777       tree types, base_types;
1778       types = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
1779       base_types = TYPE_ARG_TYPES (TREE_TYPE (base_fndecl));
1780       if ((TYPE_QUALS (TREE_TYPE (TREE_VALUE (base_types)))
1781            == TYPE_QUALS (TREE_TYPE (TREE_VALUE (types))))
1782           && compparms (TREE_CHAIN (base_types), TREE_CHAIN (types)))
1783         return 1;
1784     }
1785   return 0;
1786 }
1787
1788 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
1789    subobject.  */
1790
1791 static bool
1792 base_derived_from (tree derived, tree base)
1793 {
1794   tree probe;
1795
1796   for (probe = base; probe; probe = BINFO_INHERITANCE_CHAIN (probe))
1797     {
1798       if (probe == derived)
1799         return true;
1800       else if (BINFO_VIRTUAL_P (probe))
1801         /* If we meet a virtual base, we can't follow the inheritance
1802            any more.  See if the complete type of DERIVED contains
1803            such a virtual base.  */
1804         return (binfo_for_vbase (BINFO_TYPE (probe), BINFO_TYPE (derived))
1805                 != NULL_TREE);
1806     }
1807   return false;
1808 }
1809
1810 typedef struct find_final_overrider_data_s {
1811   /* The function for which we are trying to find a final overrider.  */
1812   tree fn;
1813   /* The base class in which the function was declared.  */
1814   tree declaring_base;
1815   /* The candidate overriders.  */
1816   tree candidates;
1817   /* Path to most derived.  */
1818   VEC(tree,heap) *path;
1819 } find_final_overrider_data;
1820
1821 /* Add the overrider along the current path to FFOD->CANDIDATES.
1822    Returns true if an overrider was found; false otherwise.  */
1823
1824 static bool
1825 dfs_find_final_overrider_1 (tree binfo,
1826                             find_final_overrider_data *ffod,
1827                             unsigned depth)
1828 {
1829   tree method;
1830
1831   /* If BINFO is not the most derived type, try a more derived class.
1832      A definition there will overrider a definition here.  */
1833   if (depth)
1834     {
1835       depth--;
1836       if (dfs_find_final_overrider_1
1837           (VEC_index (tree, ffod->path, depth), ffod, depth))
1838         return true;
1839     }
1840
1841   method = look_for_overrides_here (BINFO_TYPE (binfo), ffod->fn);
1842   if (method)
1843     {
1844       tree *candidate = &ffod->candidates;
1845
1846       /* Remove any candidates overridden by this new function.  */
1847       while (*candidate)
1848         {
1849           /* If *CANDIDATE overrides METHOD, then METHOD
1850              cannot override anything else on the list.  */
1851           if (base_derived_from (TREE_VALUE (*candidate), binfo))
1852             return true;
1853           /* If METHOD overrides *CANDIDATE, remove *CANDIDATE.  */
1854           if (base_derived_from (binfo, TREE_VALUE (*candidate)))
1855             *candidate = TREE_CHAIN (*candidate);
1856           else
1857             candidate = &TREE_CHAIN (*candidate);
1858         }
1859
1860       /* Add the new function.  */
1861       ffod->candidates = tree_cons (method, binfo, ffod->candidates);
1862       return true;
1863     }
1864
1865   return false;
1866 }
1867
1868 /* Called from find_final_overrider via dfs_walk.  */
1869
1870 static tree
1871 dfs_find_final_overrider_pre (tree binfo, void *data)
1872 {
1873   find_final_overrider_data *ffod = (find_final_overrider_data *) data;
1874
1875   if (binfo == ffod->declaring_base)
1876     dfs_find_final_overrider_1 (binfo, ffod, VEC_length (tree, ffod->path));
1877   VEC_safe_push (tree, heap, ffod->path, binfo);
1878
1879   return NULL_TREE;
1880 }
1881
1882 static tree
1883 dfs_find_final_overrider_post (tree binfo ATTRIBUTE_UNUSED, void *data)
1884 {
1885   find_final_overrider_data *ffod = (find_final_overrider_data *) data;
1886   VEC_pop (tree, ffod->path);
1887
1888   return NULL_TREE;
1889 }
1890
1891 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
1892    FN and whose TREE_VALUE is the binfo for the base where the
1893    overriding occurs.  BINFO (in the hierarchy dominated by the binfo
1894    DERIVED) is the base object in which FN is declared.  */
1895
1896 static tree
1897 find_final_overrider (tree derived, tree binfo, tree fn)
1898 {
1899   find_final_overrider_data ffod;
1900
1901   /* Getting this right is a little tricky.  This is valid:
1902
1903        struct S { virtual void f (); };
1904        struct T { virtual void f (); };
1905        struct U : public S, public T { };
1906
1907      even though calling `f' in `U' is ambiguous.  But,
1908
1909        struct R { virtual void f(); };
1910        struct S : virtual public R { virtual void f (); };
1911        struct T : virtual public R { virtual void f (); };
1912        struct U : public S, public T { };
1913
1914      is not -- there's no way to decide whether to put `S::f' or
1915      `T::f' in the vtable for `R'.
1916
1917      The solution is to look at all paths to BINFO.  If we find
1918      different overriders along any two, then there is a problem.  */
1919   if (DECL_THUNK_P (fn))
1920     fn = THUNK_TARGET (fn);
1921
1922   /* Determine the depth of the hierarchy.  */
1923   ffod.fn = fn;
1924   ffod.declaring_base = binfo;
1925   ffod.candidates = NULL_TREE;
1926   ffod.path = VEC_alloc (tree, heap, 30);
1927
1928   dfs_walk_all (derived, dfs_find_final_overrider_pre,
1929                 dfs_find_final_overrider_post, &ffod);
1930
1931   VEC_free (tree, heap, ffod.path);
1932
1933   /* If there was no winner, issue an error message.  */
1934   if (!ffod.candidates || TREE_CHAIN (ffod.candidates))
1935     return error_mark_node;
1936
1937   return ffod.candidates;
1938 }
1939
1940 /* Return the index of the vcall offset for FN when TYPE is used as a
1941    virtual base.  */
1942
1943 static tree
1944 get_vcall_index (tree fn, tree type)
1945 {
1946   VEC(tree_pair_s,gc) *indices = CLASSTYPE_VCALL_INDICES (type);
1947   tree_pair_p p;
1948   unsigned ix;
1949
1950   for (ix = 0; VEC_iterate (tree_pair_s, indices, ix, p); ix++)
1951     if ((DECL_DESTRUCTOR_P (fn) && DECL_DESTRUCTOR_P (p->purpose))
1952         || same_signature_p (fn, p->purpose))
1953       return p->value;
1954
1955   /* There should always be an appropriate index.  */
1956   gcc_unreachable ();
1957 }
1958
1959 /* Update an entry in the vtable for BINFO, which is in the hierarchy
1960    dominated by T.  FN has been overridden in BINFO; VIRTUALS points to the
1961    corresponding position in the BINFO_VIRTUALS list.  */
1962
1963 static void
1964 update_vtable_entry_for_fn (tree t, tree binfo, tree fn, tree* virtuals,
1965                             unsigned ix)
1966 {
1967   tree b;
1968   tree overrider;
1969   tree delta;
1970   tree virtual_base;
1971   tree first_defn;
1972   tree overrider_fn, overrider_target;
1973   tree target_fn = DECL_THUNK_P (fn) ? THUNK_TARGET (fn) : fn;
1974   tree over_return, base_return;
1975   bool lost = false;
1976
1977   /* Find the nearest primary base (possibly binfo itself) which defines
1978      this function; this is the class the caller will convert to when
1979      calling FN through BINFO.  */
1980   for (b = binfo; ; b = get_primary_binfo (b))
1981     {
1982       gcc_assert (b);
1983       if (look_for_overrides_here (BINFO_TYPE (b), target_fn))
1984         break;
1985
1986       /* The nearest definition is from a lost primary.  */
1987       if (BINFO_LOST_PRIMARY_P (b))
1988         lost = true;
1989     }
1990   first_defn = b;
1991
1992   /* Find the final overrider.  */
1993   overrider = find_final_overrider (TYPE_BINFO (t), b, target_fn);
1994   if (overrider == error_mark_node)
1995     {
1996       error ("no unique final overrider for %qD in %qT", target_fn, t);
1997       return;
1998     }
1999   overrider_target = overrider_fn = TREE_PURPOSE (overrider);
2000
2001   /* Check for adjusting covariant return types.  */
2002   over_return = TREE_TYPE (TREE_TYPE (overrider_target));
2003   base_return = TREE_TYPE (TREE_TYPE (target_fn));
2004
2005   if (POINTER_TYPE_P (over_return)
2006       && TREE_CODE (over_return) == TREE_CODE (base_return)
2007       && CLASS_TYPE_P (TREE_TYPE (over_return))
2008       && CLASS_TYPE_P (TREE_TYPE (base_return))
2009       /* If the overrider is invalid, don't even try.  */
2010       && !DECL_INVALID_OVERRIDER_P (overrider_target))
2011     {
2012       /* If FN is a covariant thunk, we must figure out the adjustment
2013          to the final base FN was converting to. As OVERRIDER_TARGET might
2014          also be converting to the return type of FN, we have to
2015          combine the two conversions here.  */
2016       tree fixed_offset, virtual_offset;
2017
2018       over_return = TREE_TYPE (over_return);
2019       base_return = TREE_TYPE (base_return);
2020
2021       if (DECL_THUNK_P (fn))
2022         {
2023           gcc_assert (DECL_RESULT_THUNK_P (fn));
2024           fixed_offset = ssize_int (THUNK_FIXED_OFFSET (fn));
2025           virtual_offset = THUNK_VIRTUAL_OFFSET (fn);
2026         }
2027       else
2028         fixed_offset = virtual_offset = NULL_TREE;
2029
2030       if (virtual_offset)
2031         /* Find the equivalent binfo within the return type of the
2032            overriding function. We will want the vbase offset from
2033            there.  */
2034         virtual_offset = binfo_for_vbase (BINFO_TYPE (virtual_offset),
2035                                           over_return);
2036       else if (!same_type_ignoring_top_level_qualifiers_p
2037                (over_return, base_return))
2038         {
2039           /* There was no existing virtual thunk (which takes
2040              precedence).  So find the binfo of the base function's
2041              return type within the overriding function's return type.
2042              We cannot call lookup base here, because we're inside a
2043              dfs_walk, and will therefore clobber the BINFO_MARKED
2044              flags.  Fortunately we know the covariancy is valid (it
2045              has already been checked), so we can just iterate along
2046              the binfos, which have been chained in inheritance graph
2047              order.  Of course it is lame that we have to repeat the
2048              search here anyway -- we should really be caching pieces
2049              of the vtable and avoiding this repeated work.  */
2050           tree thunk_binfo, base_binfo;
2051
2052           /* Find the base binfo within the overriding function's
2053              return type.  We will always find a thunk_binfo, except
2054              when the covariancy is invalid (which we will have
2055              already diagnosed).  */
2056           for (base_binfo = TYPE_BINFO (base_return),
2057                thunk_binfo = TYPE_BINFO (over_return);
2058                thunk_binfo;
2059                thunk_binfo = TREE_CHAIN (thunk_binfo))
2060             if (SAME_BINFO_TYPE_P (BINFO_TYPE (thunk_binfo),
2061                                    BINFO_TYPE (base_binfo)))
2062               break;
2063
2064           /* See if virtual inheritance is involved.  */
2065           for (virtual_offset = thunk_binfo;
2066                virtual_offset;
2067                virtual_offset = BINFO_INHERITANCE_CHAIN (virtual_offset))
2068             if (BINFO_VIRTUAL_P (virtual_offset))
2069               break;
2070
2071           if (virtual_offset
2072               || (thunk_binfo && !BINFO_OFFSET_ZEROP (thunk_binfo)))
2073             {
2074               tree offset = convert (ssizetype, BINFO_OFFSET (thunk_binfo));
2075
2076               if (virtual_offset)
2077                 {
2078                   /* We convert via virtual base.  Adjust the fixed
2079                      offset to be from there.  */
2080                   offset = size_diffop
2081                     (offset, convert
2082                      (ssizetype, BINFO_OFFSET (virtual_offset)));
2083                 }
2084               if (fixed_offset)
2085                 /* There was an existing fixed offset, this must be
2086                    from the base just converted to, and the base the
2087                    FN was thunking to.  */
2088                 fixed_offset = size_binop (PLUS_EXPR, fixed_offset, offset);
2089               else
2090                 fixed_offset = offset;
2091             }
2092         }
2093
2094       if (fixed_offset || virtual_offset)
2095         /* Replace the overriding function with a covariant thunk.  We
2096            will emit the overriding function in its own slot as
2097            well.  */
2098         overrider_fn = make_thunk (overrider_target, /*this_adjusting=*/0,
2099                                    fixed_offset, virtual_offset);
2100     }
2101   else
2102     gcc_assert (!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     }
2347 }
2348
2349 /* Warn about hidden virtual functions that are not overridden in t.
2350    We know that constructors and destructors don't apply.  */
2351
2352 static void
2353 warn_hidden (tree t)
2354 {
2355   VEC(tree,gc) *method_vec = CLASSTYPE_METHOD_VEC (t);
2356   tree fns;
2357   size_t i;
2358
2359   /* We go through each separately named virtual function.  */
2360   for (i = CLASSTYPE_FIRST_CONVERSION_SLOT;
2361        VEC_iterate (tree, method_vec, i, fns);
2362        ++i)
2363     {
2364       tree fn;
2365       tree name;
2366       tree fndecl;
2367       tree base_fndecls;
2368       tree base_binfo;
2369       tree binfo;
2370       int j;
2371
2372       /* All functions in this slot in the CLASSTYPE_METHOD_VEC will
2373          have the same name.  Figure out what name that is.  */
2374       name = DECL_NAME (OVL_CURRENT (fns));
2375       /* There are no possibly hidden functions yet.  */
2376       base_fndecls = NULL_TREE;
2377       /* Iterate through all of the base classes looking for possibly
2378          hidden functions.  */
2379       for (binfo = TYPE_BINFO (t), j = 0;
2380            BINFO_BASE_ITERATE (binfo, j, base_binfo); j++)
2381         {
2382           tree basetype = BINFO_TYPE (base_binfo);
2383           base_fndecls = chainon (get_basefndecls (name, basetype),
2384                                   base_fndecls);
2385         }
2386
2387       /* If there are no functions to hide, continue.  */
2388       if (!base_fndecls)
2389         continue;
2390
2391       /* Remove any overridden functions.  */
2392       for (fn = fns; fn; fn = OVL_NEXT (fn))
2393         {
2394           fndecl = OVL_CURRENT (fn);
2395           if (DECL_VINDEX (fndecl))
2396             {
2397               tree *prev = &base_fndecls;
2398
2399               while (*prev)
2400                 /* If the method from the base class has the same
2401                    signature as the method from the derived class, it
2402                    has been overridden.  */
2403                 if (same_signature_p (fndecl, TREE_VALUE (*prev)))
2404                   *prev = TREE_CHAIN (*prev);
2405                 else
2406                   prev = &TREE_CHAIN (*prev);
2407             }
2408         }
2409
2410       /* Now give a warning for all base functions without overriders,
2411          as they are hidden.  */
2412       while (base_fndecls)
2413         {
2414           /* Here we know it is a hider, and no overrider exists.  */
2415           warning (0, "%q+D was hidden", TREE_VALUE (base_fndecls));
2416           warning (0, "  by %q+D", fns);
2417           base_fndecls = TREE_CHAIN (base_fndecls);
2418         }
2419     }
2420 }
2421
2422 /* Check for things that are invalid.  There are probably plenty of other
2423    things we should check for also.  */
2424
2425 static void
2426 finish_struct_anon (tree t)
2427 {
2428   tree field;
2429
2430   for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
2431     {
2432       if (TREE_STATIC (field))
2433         continue;
2434       if (TREE_CODE (field) != FIELD_DECL)
2435         continue;
2436
2437       if (DECL_NAME (field) == NULL_TREE
2438           && ANON_AGGR_TYPE_P (TREE_TYPE (field)))
2439         {
2440           tree elt = TYPE_FIELDS (TREE_TYPE (field));
2441           for (; elt; elt = TREE_CHAIN (elt))
2442             {
2443               /* We're generally only interested in entities the user
2444                  declared, but we also find nested classes by noticing
2445                  the TYPE_DECL that we create implicitly.  You're
2446                  allowed to put one anonymous union inside another,
2447                  though, so we explicitly tolerate that.  We use
2448                  TYPE_ANONYMOUS_P rather than ANON_AGGR_TYPE_P so that
2449                  we also allow unnamed types used for defining fields.  */
2450               if (DECL_ARTIFICIAL (elt)
2451                   && (!DECL_IMPLICIT_TYPEDEF_P (elt)
2452                       || TYPE_ANONYMOUS_P (TREE_TYPE (elt))))
2453                 continue;
2454
2455               if (TREE_CODE (elt) != FIELD_DECL)
2456                 {
2457                   pedwarn ("%q+#D invalid; an anonymous union can "
2458                            "only have non-static data members", elt);
2459                   continue;
2460                 }
2461
2462               if (TREE_PRIVATE (elt))
2463                 pedwarn ("private member %q+#D in anonymous union", elt);
2464               else if (TREE_PROTECTED (elt))
2465                 pedwarn ("protected member %q+#D in anonymous union", elt);
2466
2467               TREE_PRIVATE (elt) = TREE_PRIVATE (field);
2468               TREE_PROTECTED (elt) = TREE_PROTECTED (field);
2469             }
2470         }
2471     }
2472 }
2473
2474 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2475    will be used later during class template instantiation.
2476    When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2477    a non-static member data (FIELD_DECL), a member function
2478    (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2479    a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2480    When FRIEND_P is nonzero, T is either a friend class
2481    (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2482    (FUNCTION_DECL, TEMPLATE_DECL).  */
2483
2484 void
2485 maybe_add_class_template_decl_list (tree type, tree t, int friend_p)
2486 {
2487   /* Save some memory by not creating TREE_LIST if TYPE is not template.  */
2488   if (CLASSTYPE_TEMPLATE_INFO (type))
2489     CLASSTYPE_DECL_LIST (type)
2490       = tree_cons (friend_p ? NULL_TREE : type,
2491                    t, CLASSTYPE_DECL_LIST (type));
2492 }
2493
2494 /* Create default constructors, assignment operators, and so forth for
2495    the type indicated by T, if they are needed.  CANT_HAVE_CONST_CTOR,
2496    and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
2497    the class cannot have a default constructor, copy constructor
2498    taking a const reference argument, or an assignment operator taking
2499    a const reference, respectively.  */
2500
2501 static void
2502 add_implicitly_declared_members (tree t,
2503                                  int cant_have_const_cctor,
2504                                  int cant_have_const_assignment)
2505 {
2506   /* Destructor.  */
2507   if (!CLASSTYPE_DESTRUCTORS (t))
2508     {
2509       /* In general, we create destructors lazily.  */
2510       CLASSTYPE_LAZY_DESTRUCTOR (t) = 1;
2511       /* However, if the implicit destructor is non-trivial
2512          destructor, we sometimes have to create it at this point.  */
2513       if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t))
2514         {
2515           bool lazy_p = true;
2516
2517           if (TYPE_FOR_JAVA (t))
2518             /* If this a Java class, any non-trivial destructor is
2519                invalid, even if compiler-generated.  Therefore, if the
2520                destructor is non-trivial we create it now.  */
2521             lazy_p = false;
2522           else
2523             {
2524               tree binfo;
2525               tree base_binfo;
2526               int ix;
2527
2528               /* If the implicit destructor will be virtual, then we must
2529                  generate it now because (unfortunately) we do not
2530                  generate virtual tables lazily.  */
2531               binfo = TYPE_BINFO (t);
2532               for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++)
2533                 {
2534                   tree base_type;
2535                   tree dtor;
2536
2537                   base_type = BINFO_TYPE (base_binfo);
2538                   dtor = CLASSTYPE_DESTRUCTORS (base_type);
2539                   if (dtor && DECL_VIRTUAL_P (dtor))
2540                     {
2541                       lazy_p = false;
2542                       break;
2543                     }
2544                 }
2545             }
2546
2547           /* If we can't get away with being lazy, generate the destructor
2548              now.  */
2549           if (!lazy_p)
2550             lazily_declare_fn (sfk_destructor, t);
2551         }
2552     }
2553
2554   /* Default constructor.  */
2555   if (! TYPE_HAS_CONSTRUCTOR (t))
2556     {
2557       TYPE_HAS_DEFAULT_CONSTRUCTOR (t) = 1;
2558       CLASSTYPE_LAZY_DEFAULT_CTOR (t) = 1;
2559     }
2560
2561   /* Copy constructor.  */
2562   if (! TYPE_HAS_INIT_REF (t) && ! TYPE_FOR_JAVA (t))
2563     {
2564       TYPE_HAS_INIT_REF (t) = 1;
2565       TYPE_HAS_CONST_INIT_REF (t) = !cant_have_const_cctor;
2566       CLASSTYPE_LAZY_COPY_CTOR (t) = 1;
2567       TYPE_HAS_CONSTRUCTOR (t) = 1;
2568     }
2569
2570   /* If there is no assignment operator, one will be created if and
2571      when it is needed.  For now, just record whether or not the type
2572      of the parameter to the assignment operator will be a const or
2573      non-const reference.  */
2574   if (!TYPE_HAS_ASSIGN_REF (t) && !TYPE_FOR_JAVA (t))
2575     {
2576       TYPE_HAS_ASSIGN_REF (t) = 1;
2577       TYPE_HAS_CONST_ASSIGN_REF (t) = !cant_have_const_assignment;
2578       CLASSTYPE_LAZY_ASSIGNMENT_OP (t) = 1;
2579     }
2580 }
2581
2582 /* Subroutine of finish_struct_1.  Recursively count the number of fields
2583    in TYPE, including anonymous union members.  */
2584
2585 static int
2586 count_fields (tree fields)
2587 {
2588   tree x;
2589   int n_fields = 0;
2590   for (x = fields; x; x = TREE_CHAIN (x))
2591     {
2592       if (TREE_CODE (x) == FIELD_DECL && ANON_AGGR_TYPE_P (TREE_TYPE (x)))
2593         n_fields += count_fields (TYPE_FIELDS (TREE_TYPE (x)));
2594       else
2595         n_fields += 1;
2596     }
2597   return n_fields;
2598 }
2599
2600 /* Subroutine of finish_struct_1.  Recursively add all the fields in the
2601    TREE_LIST FIELDS to the SORTED_FIELDS_TYPE elts, starting at offset IDX.  */
2602
2603 static int
2604 add_fields_to_record_type (tree fields, struct sorted_fields_type *field_vec, int idx)
2605 {
2606   tree x;
2607   for (x = fields; x; x = TREE_CHAIN (x))
2608     {
2609       if (TREE_CODE (x) == FIELD_DECL && ANON_AGGR_TYPE_P (TREE_TYPE (x)))
2610         idx = add_fields_to_record_type (TYPE_FIELDS (TREE_TYPE (x)), field_vec, idx);
2611       else
2612         field_vec->elts[idx++] = x;
2613     }
2614   return idx;
2615 }
2616
2617 /* FIELD is a bit-field.  We are finishing the processing for its
2618    enclosing type.  Issue any appropriate messages and set appropriate
2619    flags.  */
2620
2621 static void
2622 check_bitfield_decl (tree field)
2623 {
2624   tree type = TREE_TYPE (field);
2625   tree w = NULL_TREE;
2626
2627   /* Detect invalid bit-field type.  */
2628   if (DECL_INITIAL (field)
2629       && ! INTEGRAL_TYPE_P (TREE_TYPE (field)))
2630     {
2631       error ("bit-field %q+#D with non-integral type", field);
2632       w = error_mark_node;
2633     }
2634
2635   /* Detect and ignore out of range field width.  */
2636   if (DECL_INITIAL (field))
2637     {
2638       w = DECL_INITIAL (field);
2639
2640       /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs.  */
2641       STRIP_NOPS (w);
2642
2643       /* detect invalid field size.  */
2644       w = integral_constant_value (w);
2645
2646       if (TREE_CODE (w) != INTEGER_CST)
2647         {
2648           error ("bit-field %q+D width not an integer constant", field);
2649           w = error_mark_node;
2650         }
2651       else if (tree_int_cst_sgn (w) < 0)
2652         {
2653           error ("negative width in bit-field %q+D", field);
2654           w = error_mark_node;
2655         }
2656       else if (integer_zerop (w) && DECL_NAME (field) != 0)
2657         {
2658           error ("zero width for bit-field %q+D", field);
2659           w = error_mark_node;
2660         }
2661       else if (compare_tree_int (w, TYPE_PRECISION (type)) > 0
2662                && TREE_CODE (type) != ENUMERAL_TYPE
2663                && TREE_CODE (type) != BOOLEAN_TYPE)
2664         warning (0, "width of %q+D exceeds its type", field);
2665       else if (TREE_CODE (type) == ENUMERAL_TYPE
2666                && (0 > compare_tree_int (w,
2667                                          min_precision (TYPE_MIN_VALUE (type),
2668                                                         TYPE_UNSIGNED (type)))
2669                    ||  0 > compare_tree_int (w,
2670                                              min_precision
2671                                              (TYPE_MAX_VALUE (type),
2672                                               TYPE_UNSIGNED (type)))))
2673         warning (0, "%q+D is too small to hold all values of %q#T", field, type);
2674     }
2675
2676   /* Remove the bit-field width indicator so that the rest of the
2677      compiler does not treat that value as an initializer.  */
2678   DECL_INITIAL (field) = NULL_TREE;
2679
2680   if (w != error_mark_node)
2681     {
2682       DECL_SIZE (field) = convert (bitsizetype, w);
2683       DECL_BIT_FIELD (field) = 1;
2684     }
2685   else
2686     {
2687       /* Non-bit-fields are aligned for their type.  */
2688       DECL_BIT_FIELD (field) = 0;
2689       CLEAR_DECL_C_BIT_FIELD (field);
2690     }
2691 }
2692
2693 /* FIELD is a non bit-field.  We are finishing the processing for its
2694    enclosing type T.  Issue any appropriate messages and set appropriate
2695    flags.  */
2696
2697 static void
2698 check_field_decl (tree field,
2699                   tree t,
2700                   int* cant_have_const_ctor,
2701                   int* no_const_asn_ref,
2702                   int* any_default_members)
2703 {
2704   tree type = strip_array_types (TREE_TYPE (field));
2705
2706   /* An anonymous union cannot contain any fields which would change
2707      the settings of CANT_HAVE_CONST_CTOR and friends.  */
2708   if (ANON_UNION_TYPE_P (type))
2709     ;
2710   /* And, we don't set TYPE_HAS_CONST_INIT_REF, etc., for anonymous
2711      structs.  So, we recurse through their fields here.  */
2712   else if (ANON_AGGR_TYPE_P (type))
2713     {
2714       tree fields;
2715
2716       for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields))
2717         if (TREE_CODE (fields) == FIELD_DECL && !DECL_C_BIT_FIELD (field))
2718           check_field_decl (fields, t, cant_have_const_ctor,
2719                             no_const_asn_ref, any_default_members);
2720     }
2721   /* Check members with class type for constructors, destructors,
2722      etc.  */
2723   else if (CLASS_TYPE_P (type))
2724     {
2725       /* Never let anything with uninheritable virtuals
2726          make it through without complaint.  */
2727       abstract_virtuals_error (field, type);
2728
2729       if (TREE_CODE (t) == UNION_TYPE)
2730         {
2731           if (TYPE_NEEDS_CONSTRUCTING (type))
2732             error ("member %q+#D with constructor not allowed in union",
2733                    field);
2734           if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
2735             error ("member %q+#D with destructor not allowed in union", field);
2736           if (TYPE_HAS_COMPLEX_ASSIGN_REF (type))
2737             error ("member %q+#D with copy assignment operator not allowed in union",
2738                    field);
2739         }
2740       else
2741         {
2742           TYPE_NEEDS_CONSTRUCTING (t) |= TYPE_NEEDS_CONSTRUCTING (type);
2743           TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
2744             |= TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type);
2745           TYPE_HAS_COMPLEX_ASSIGN_REF (t) |= TYPE_HAS_COMPLEX_ASSIGN_REF (type);
2746           TYPE_HAS_COMPLEX_INIT_REF (t) |= TYPE_HAS_COMPLEX_INIT_REF (type);
2747         }
2748
2749       if (!TYPE_HAS_CONST_INIT_REF (type))
2750         *cant_have_const_ctor = 1;
2751
2752       if (!TYPE_HAS_CONST_ASSIGN_REF (type))
2753         *no_const_asn_ref = 1;
2754     }
2755   if (DECL_INITIAL (field) != NULL_TREE)
2756     {
2757       /* `build_class_init_list' does not recognize
2758          non-FIELD_DECLs.  */
2759       if (TREE_CODE (t) == UNION_TYPE && any_default_members != 0)
2760         error ("multiple fields in union %qT initialized", t);
2761       *any_default_members = 1;
2762     }
2763 }
2764
2765 /* Check the data members (both static and non-static), class-scoped
2766    typedefs, etc., appearing in the declaration of T.  Issue
2767    appropriate diagnostics.  Sets ACCESS_DECLS to a list (in
2768    declaration order) of access declarations; each TREE_VALUE in this
2769    list is a USING_DECL.
2770
2771    In addition, set the following flags:
2772
2773      EMPTY_P
2774        The class is empty, i.e., contains no non-static data members.
2775
2776      CANT_HAVE_CONST_CTOR_P
2777        This class cannot have an implicitly generated copy constructor
2778        taking a const reference.
2779
2780      CANT_HAVE_CONST_ASN_REF
2781        This class cannot have an implicitly generated assignment
2782        operator taking a const reference.
2783
2784    All of these flags should be initialized before calling this
2785    function.
2786
2787    Returns a pointer to the end of the TYPE_FIELDs chain; additional
2788    fields can be added by adding to this chain.  */
2789
2790 static void
2791 check_field_decls (tree t, tree *access_decls,
2792                    int *cant_have_const_ctor_p,
2793                    int *no_const_asn_ref_p)
2794 {
2795   tree *field;
2796   tree *next;
2797   bool has_pointers;
2798   int any_default_members;
2799
2800   /* Assume there are no access declarations.  */
2801   *access_decls = NULL_TREE;
2802   /* Assume this class has no pointer members.  */
2803   has_pointers = false;
2804   /* Assume none of the members of this class have default
2805      initializations.  */
2806   any_default_members = 0;
2807
2808   for (field = &TYPE_FIELDS (t); *field; field = next)
2809     {
2810       tree x = *field;
2811       tree type = TREE_TYPE (x);
2812
2813       next = &TREE_CHAIN (x);
2814
2815       if (TREE_CODE (x) == FIELD_DECL)
2816         {
2817           if (TYPE_PACKED (t))
2818             {
2819               if (!pod_type_p (TREE_TYPE (x)) && !TYPE_PACKED (TREE_TYPE (x)))
2820                 warning
2821                   (0,
2822                    "ignoring packed attribute on unpacked non-POD field %q+#D",
2823                    x);
2824               else if (TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
2825                 DECL_PACKED (x) = 1;
2826             }
2827
2828           if (DECL_C_BIT_FIELD (x) && integer_zerop (DECL_INITIAL (x)))
2829             /* We don't treat zero-width bitfields as making a class
2830                non-empty.  */
2831             ;
2832           else
2833             {
2834               tree element_type;
2835
2836               /* The class is non-empty.  */
2837               CLASSTYPE_EMPTY_P (t) = 0;
2838               /* The class is not even nearly empty.  */
2839               CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
2840               /* If one of the data members contains an empty class,
2841                  so does T.  */
2842               element_type = strip_array_types (type);
2843               if (CLASS_TYPE_P (element_type)
2844                   && CLASSTYPE_CONTAINS_EMPTY_CLASS_P (element_type))
2845                 CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
2846             }
2847         }
2848
2849       if (TREE_CODE (x) == USING_DECL)
2850         {
2851           /* Prune the access declaration from the list of fields.  */
2852           *field = TREE_CHAIN (x);
2853
2854           /* Save the access declarations for our caller.  */
2855           *access_decls = tree_cons (NULL_TREE, x, *access_decls);
2856
2857           /* Since we've reset *FIELD there's no reason to skip to the
2858              next field.  */
2859           next = field;
2860           continue;
2861         }
2862
2863       if (TREE_CODE (x) == TYPE_DECL
2864           || TREE_CODE (x) == TEMPLATE_DECL)
2865         continue;
2866
2867       /* If we've gotten this far, it's a data member, possibly static,
2868          or an enumerator.  */
2869       DECL_CONTEXT (x) = t;
2870
2871       /* When this goes into scope, it will be a non-local reference.  */
2872       DECL_NONLOCAL (x) = 1;
2873
2874       if (TREE_CODE (t) == UNION_TYPE)
2875         {
2876           /* [class.union]
2877
2878              If a union contains a static data member, or a member of
2879              reference type, the program is ill-formed.  */
2880           if (TREE_CODE (x) == VAR_DECL)
2881             {
2882               error ("%q+D may not be static because it is a member of a union", x);
2883               continue;
2884             }
2885           if (TREE_CODE (type) == REFERENCE_TYPE)
2886             {
2887               error ("%q+D may not have reference type %qT because"
2888                      " it is a member of a union",
2889                      x, type);
2890               continue;
2891             }
2892         }
2893
2894       /* ``A local class cannot have static data members.'' ARM 9.4 */
2895       if (current_function_decl && TREE_STATIC (x))
2896         error ("field %q+D in local class cannot be static", x);
2897
2898       /* Perform error checking that did not get done in
2899          grokdeclarator.  */
2900       if (TREE_CODE (type) == FUNCTION_TYPE)
2901         {
2902           error ("field %q+D invalidly declared function type", x);
2903           type = build_pointer_type (type);
2904           TREE_TYPE (x) = type;
2905         }
2906       else if (TREE_CODE (type) == METHOD_TYPE)
2907         {
2908           error ("field %q+D invalidly declared method type", x);
2909           type = build_pointer_type (type);
2910           TREE_TYPE (x) = type;
2911         }
2912
2913       if (type == error_mark_node)
2914         continue;
2915
2916       if (TREE_CODE (x) == CONST_DECL || TREE_CODE (x) == VAR_DECL)
2917         continue;
2918
2919       /* Now it can only be a FIELD_DECL.  */
2920
2921       if (TREE_PRIVATE (x) || TREE_PROTECTED (x))
2922         CLASSTYPE_NON_AGGREGATE (t) = 1;
2923
2924       /* If this is of reference type, check if it needs an init.
2925          Also do a little ANSI jig if necessary.  */
2926       if (TREE_CODE (type) == REFERENCE_TYPE)
2927         {
2928           CLASSTYPE_NON_POD_P (t) = 1;
2929           if (DECL_INITIAL (x) == NULL_TREE)
2930             SET_CLASSTYPE_REF_FIELDS_NEED_INIT (t, 1);
2931
2932           /* ARM $12.6.2: [A member initializer list] (or, for an
2933              aggregate, initialization by a brace-enclosed list) is the
2934              only way to initialize nonstatic const and reference
2935              members.  */
2936           TYPE_HAS_COMPLEX_ASSIGN_REF (t) = 1;
2937
2938           if (! TYPE_HAS_CONSTRUCTOR (t) && CLASSTYPE_NON_AGGREGATE (t)
2939               && extra_warnings)
2940             warning (OPT_Wextra, "non-static reference %q+#D in class without a constructor", x);
2941         }
2942
2943       type = strip_array_types (type);
2944
2945       /* This is used by -Weffc++ (see below). Warn only for pointers
2946          to members which might hold dynamic memory. So do not warn
2947          for pointers to functions or pointers to members.  */
2948       if (TYPE_PTR_P (type)
2949           && !TYPE_PTRFN_P (type)
2950           && !TYPE_PTR_TO_MEMBER_P (type))
2951         has_pointers = true;
2952
2953       if (CLASS_TYPE_P (type))
2954         {
2955           if (CLASSTYPE_REF_FIELDS_NEED_INIT (type))
2956             SET_CLASSTYPE_REF_FIELDS_NEED_INIT (t, 1);
2957           if (CLASSTYPE_READONLY_FIELDS_NEED_INIT (type))
2958             SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t, 1);
2959         }
2960
2961       if (DECL_MUTABLE_P (x) || TYPE_HAS_MUTABLE_P (type))
2962         CLASSTYPE_HAS_MUTABLE (t) = 1;
2963
2964       if (! pod_type_p (type))
2965         /* DR 148 now allows pointers to members (which are POD themselves),
2966            to be allowed in POD structs.  */
2967         CLASSTYPE_NON_POD_P (t) = 1;
2968
2969       if (! zero_init_p (type))
2970         CLASSTYPE_NON_ZERO_INIT_P (t) = 1;
2971
2972       /* If any field is const, the structure type is pseudo-const.  */
2973       if (CP_TYPE_CONST_P (type))
2974         {
2975           C_TYPE_FIELDS_READONLY (t) = 1;
2976           if (DECL_INITIAL (x) == NULL_TREE)
2977             SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t, 1);
2978
2979           /* ARM $12.6.2: [A member initializer list] (or, for an
2980              aggregate, initialization by a brace-enclosed list) is the
2981              only way to initialize nonstatic const and reference
2982              members.  */
2983           TYPE_HAS_COMPLEX_ASSIGN_REF (t) = 1;
2984
2985           if (! TYPE_HAS_CONSTRUCTOR (t) && CLASSTYPE_NON_AGGREGATE (t)
2986               && extra_warnings)
2987             warning (OPT_Wextra, "non-static const member %q+#D in class without a constructor", x);
2988         }
2989       /* A field that is pseudo-const makes the structure likewise.  */
2990       else if (CLASS_TYPE_P (type))
2991         {
2992           C_TYPE_FIELDS_READONLY (t) |= C_TYPE_FIELDS_READONLY (type);
2993           SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t,
2994             CLASSTYPE_READONLY_FIELDS_NEED_INIT (t)
2995             | CLASSTYPE_READONLY_FIELDS_NEED_INIT (type));
2996         }
2997
2998       /* Core issue 80: A nonstatic data member is required to have a
2999          different name from the class iff the class has a
3000          user-defined constructor.  */
3001       if (constructor_name_p (DECL_NAME (x), t) && TYPE_HAS_CONSTRUCTOR (t))
3002         pedwarn ("field %q+#D with same name as class", x);
3003
3004       /* We set DECL_C_BIT_FIELD in grokbitfield.
3005          If the type and width are valid, we'll also set DECL_BIT_FIELD.  */
3006       if (DECL_C_BIT_FIELD (x))
3007         check_bitfield_decl (x);
3008       else
3009         check_field_decl (x, t,
3010                           cant_have_const_ctor_p,
3011                           no_const_asn_ref_p,
3012                           &any_default_members);
3013     }
3014
3015   /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3016      it should also define a copy constructor and an assignment operator to
3017      implement the correct copy semantic (deep vs shallow, etc.). As it is
3018      not feasible to check whether the constructors do allocate dynamic memory
3019      and store it within members, we approximate the warning like this:
3020
3021      -- Warn only if there are members which are pointers
3022      -- Warn only if there is a non-trivial constructor (otherwise,
3023         there cannot be memory allocated).
3024      -- Warn only if there is a non-trivial destructor. We assume that the
3025         user at least implemented the cleanup correctly, and a destructor
3026         is needed to free dynamic memory.
3027
3028      This seems enough for practical purposes.  */
3029     if (warn_ecpp
3030         && has_pointers
3031         && TYPE_HAS_CONSTRUCTOR (t)
3032         && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
3033         && !(TYPE_HAS_INIT_REF (t) && TYPE_HAS_ASSIGN_REF (t)))
3034     {
3035       warning (OPT_Weffc__, "%q#T has pointer data members", t);
3036
3037       if (! TYPE_HAS_INIT_REF (t))
3038         {
3039           warning (OPT_Weffc__,
3040                    "  but does not override %<%T(const %T&)%>", t, t);
3041           if (!TYPE_HAS_ASSIGN_REF (t))
3042             warning (OPT_Weffc__, "  or %<operator=(const %T&)%>", t);
3043         }
3044       else if (! TYPE_HAS_ASSIGN_REF (t))
3045         warning (OPT_Weffc__,
3046                  "  but does not override %<operator=(const %T&)%>", t);
3047     }
3048
3049
3050   /* Check anonymous struct/anonymous union fields.  */
3051   finish_struct_anon (t);
3052
3053   /* We've built up the list of access declarations in reverse order.
3054      Fix that now.  */
3055   *access_decls = nreverse (*access_decls);
3056 }
3057
3058 /* If TYPE is an empty class type, records its OFFSET in the table of
3059    OFFSETS.  */
3060
3061 static int
3062 record_subobject_offset (tree type, tree offset, splay_tree offsets)
3063 {
3064   splay_tree_node n;
3065
3066   if (!is_empty_class (type))
3067     return 0;
3068
3069   /* Record the location of this empty object in OFFSETS.  */
3070   n = splay_tree_lookup (offsets, (splay_tree_key) offset);
3071   if (!n)
3072     n = splay_tree_insert (offsets,
3073                            (splay_tree_key) offset,
3074                            (splay_tree_value) NULL_TREE);
3075   n->value = ((splay_tree_value)
3076               tree_cons (NULL_TREE,
3077                          type,
3078                          (tree) n->value));
3079
3080   return 0;
3081 }
3082
3083 /* Returns nonzero if TYPE is an empty class type and there is
3084    already an entry in OFFSETS for the same TYPE as the same OFFSET.  */
3085
3086 static int
3087 check_subobject_offset (tree type, tree offset, splay_tree offsets)
3088 {
3089   splay_tree_node n;
3090   tree t;
3091
3092   if (!is_empty_class (type))
3093     return 0;
3094
3095   /* Record the location of this empty object in OFFSETS.  */
3096   n = splay_tree_lookup (offsets, (splay_tree_key) offset);
3097   if (!n)
3098     return 0;
3099
3100   for (t = (tree) n->value; t; t = TREE_CHAIN (t))
3101     if (same_type_p (TREE_VALUE (t), type))
3102       return 1;
3103
3104   return 0;
3105 }
3106
3107 /* Walk through all the subobjects of TYPE (located at OFFSET).  Call
3108    F for every subobject, passing it the type, offset, and table of
3109    OFFSETS.  If VBASES_P is one, then virtual non-primary bases should
3110    be traversed.
3111
3112    If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3113    than MAX_OFFSET will not be walked.
3114
3115    If F returns a nonzero value, the traversal ceases, and that value
3116    is returned.  Otherwise, returns zero.  */
3117
3118 static int
3119 walk_subobject_offsets (tree type,
3120                         subobject_offset_fn f,
3121                         tree offset,
3122                         splay_tree offsets,
3123                         tree max_offset,
3124                         int vbases_p)
3125 {
3126   int r = 0;
3127   tree type_binfo = NULL_TREE;
3128
3129   /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3130      stop.  */
3131   if (max_offset && INT_CST_LT (max_offset, offset))
3132     return 0;
3133
3134   if (type == error_mark_node)
3135     return 0;
3136
3137   if (!TYPE_P (type))
3138     {
3139       if (abi_version_at_least (2))
3140         type_binfo = type;
3141       type = BINFO_TYPE (type);
3142     }
3143
3144   if (CLASS_TYPE_P (type))
3145     {
3146       tree field;
3147       tree binfo;
3148       int i;
3149
3150       /* Avoid recursing into objects that are not interesting.  */
3151       if (!CLASSTYPE_CONTAINS_EMPTY_CLASS_P (type))
3152         return 0;
3153
3154       /* Record the location of TYPE.  */
3155       r = (*f) (type, offset, offsets);
3156       if (r)
3157         return r;
3158
3159       /* Iterate through the direct base classes of TYPE.  */
3160       if (!type_binfo)
3161         type_binfo = TYPE_BINFO (type);
3162       for (i = 0; BINFO_BASE_ITERATE (type_binfo, i, binfo); i++)
3163         {
3164           tree binfo_offset;
3165
3166           if (abi_version_at_least (2)
3167               && BINFO_VIRTUAL_P (binfo))
3168             continue;
3169
3170           if (!vbases_p
3171               && BINFO_VIRTUAL_P (binfo)
3172               && !BINFO_PRIMARY_P (binfo))
3173             continue;
3174
3175           if (!abi_version_at_least (2))
3176             binfo_offset = size_binop (PLUS_EXPR,
3177                                        offset,
3178                                        BINFO_OFFSET (binfo));
3179           else
3180             {
3181               tree orig_binfo;
3182               /* We cannot rely on BINFO_OFFSET being set for the base
3183                  class yet, but the offsets for direct non-virtual
3184                  bases can be calculated by going back to the TYPE.  */
3185               orig_binfo = BINFO_BASE_BINFO (TYPE_BINFO (type), i);
3186               binfo_offset = size_binop (PLUS_EXPR,
3187                                          offset,
3188                                          BINFO_OFFSET (orig_binfo));
3189             }
3190
3191           r = walk_subobject_offsets (binfo,
3192                                       f,
3193                                       binfo_offset,
3194                                       offsets,
3195                                       max_offset,
3196                                       (abi_version_at_least (2)
3197                                        ? /*vbases_p=*/0 : vbases_p));
3198           if (r)
3199             return r;
3200         }
3201
3202       if (abi_version_at_least (2) && CLASSTYPE_VBASECLASSES (type))
3203         {
3204           unsigned ix;
3205           VEC(tree,gc) *vbases;
3206
3207           /* Iterate through the virtual base classes of TYPE.  In G++
3208              3.2, we included virtual bases in the direct base class
3209              loop above, which results in incorrect results; the
3210              correct offsets for virtual bases are only known when
3211              working with the most derived type.  */
3212           if (vbases_p)
3213             for (vbases = CLASSTYPE_VBASECLASSES (type), ix = 0;
3214                  VEC_iterate (tree, vbases, ix, binfo); ix++)
3215               {
3216                 r = walk_subobject_offsets (binfo,
3217                                             f,
3218                                             size_binop (PLUS_EXPR,
3219                                                         offset,
3220                                                         BINFO_OFFSET (binfo)),
3221                                             offsets,
3222                                             max_offset,
3223                                             /*vbases_p=*/0);
3224                 if (r)
3225                   return r;
3226               }
3227           else
3228             {
3229               /* We still have to walk the primary base, if it is
3230                  virtual.  (If it is non-virtual, then it was walked
3231                  above.)  */
3232               tree vbase = get_primary_binfo (type_binfo);
3233
3234               if (vbase && BINFO_VIRTUAL_P (vbase)
3235                   && BINFO_PRIMARY_P (vbase)
3236                   && BINFO_INHERITANCE_CHAIN (vbase) == type_binfo)
3237                 {
3238                   r = (walk_subobject_offsets
3239                        (vbase, f, offset,
3240                         offsets, max_offset, /*vbases_p=*/0));
3241                   if (r)
3242                     return r;
3243                 }
3244             }
3245         }
3246
3247       /* Iterate through the fields of TYPE.  */
3248       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3249         if (TREE_CODE (field) == FIELD_DECL && !DECL_ARTIFICIAL (field))
3250           {
3251             tree field_offset;
3252
3253             if (abi_version_at_least (2))
3254               field_offset = byte_position (field);
3255             else
3256               /* In G++ 3.2, DECL_FIELD_OFFSET was used.  */
3257               field_offset = DECL_FIELD_OFFSET (field);
3258
3259             r = walk_subobject_offsets (TREE_TYPE (field),
3260                                         f,
3261                                         size_binop (PLUS_EXPR,
3262                                                     offset,
3263                                                     field_offset),
3264                                         offsets,
3265                                         max_offset,
3266                                         /*vbases_p=*/1);
3267             if (r)
3268               return r;
3269           }
3270     }
3271   else if (TREE_CODE (type) == ARRAY_TYPE)
3272     {
3273       tree element_type = strip_array_types (type);
3274       tree domain = TYPE_DOMAIN (type);
3275       tree index;
3276
3277       /* Avoid recursing into objects that are not interesting.  */
3278       if (!CLASS_TYPE_P (element_type)
3279           || !CLASSTYPE_CONTAINS_EMPTY_CLASS_P (element_type))
3280         return 0;
3281
3282       /* Step through each of the elements in the array.  */
3283       for (index = size_zero_node;
3284            /* G++ 3.2 had an off-by-one error here.  */
3285            (abi_version_at_least (2)
3286             ? !INT_CST_LT (TYPE_MAX_VALUE (domain), index)
3287             : INT_CST_LT (index, TYPE_MAX_VALUE (domain)));
3288            index = size_binop (PLUS_EXPR, index, size_one_node))
3289         {
3290           r = walk_subobject_offsets (TREE_TYPE (type),
3291                                       f,
3292                                       offset,
3293                                       offsets,
3294                                       max_offset,
3295                                       /*vbases_p=*/1);
3296           if (r)
3297             return r;
3298           offset = size_binop (PLUS_EXPR, offset,
3299                                TYPE_SIZE_UNIT (TREE_TYPE (type)));
3300           /* If this new OFFSET is bigger than the MAX_OFFSET, then
3301              there's no point in iterating through the remaining
3302              elements of the array.  */
3303           if (max_offset && INT_CST_LT (max_offset, offset))
3304             break;
3305         }
3306     }
3307
3308   return 0;
3309 }
3310
3311 /* Record all of the empty subobjects of TYPE (either a type or a
3312    binfo).  If IS_DATA_MEMBER is true, then a non-static data member
3313    is being placed at OFFSET; otherwise, it is a base class that is
3314    being placed at OFFSET.  */
3315
3316 static void
3317 record_subobject_offsets (tree type,
3318                           tree offset,
3319                           splay_tree offsets,
3320                           bool is_data_member)
3321 {
3322   tree max_offset;
3323   /* If recording subobjects for a non-static data member or a
3324      non-empty base class , we do not need to record offsets beyond
3325      the size of the biggest empty class.  Additional data members
3326      will go at the end of the class.  Additional base classes will go
3327      either at offset zero (if empty, in which case they cannot
3328      overlap with offsets past the size of the biggest empty class) or
3329      at the end of the class.
3330
3331      However, if we are placing an empty base class, then we must record
3332      all offsets, as either the empty class is at offset zero (where
3333      other empty classes might later be placed) or at the end of the
3334      class (where other objects might then be placed, so other empty
3335      subobjects might later overlap).  */
3336   if (is_data_member
3337       || !is_empty_class (BINFO_TYPE (type)))
3338     max_offset = sizeof_biggest_empty_class;
3339   else
3340     max_offset = NULL_TREE;
3341   walk_subobject_offsets (type, record_subobject_offset, offset,
3342                           offsets, max_offset, is_data_member);
3343 }
3344
3345 /* Returns nonzero if any of the empty subobjects of TYPE (located at
3346    OFFSET) conflict with entries in OFFSETS.  If VBASES_P is nonzero,
3347    virtual bases of TYPE are examined.  */
3348
3349 static int
3350 layout_conflict_p (tree type,
3351                    tree offset,
3352                    splay_tree offsets,
3353                    int vbases_p)
3354 {
3355   splay_tree_node max_node;
3356
3357   /* Get the node in OFFSETS that indicates the maximum offset where
3358      an empty subobject is located.  */
3359   max_node = splay_tree_max (offsets);
3360   /* If there aren't any empty subobjects, then there's no point in
3361      performing this check.  */
3362   if (!max_node)
3363     return 0;
3364
3365   return walk_subobject_offsets (type, check_subobject_offset, offset,
3366                                  offsets, (tree) (max_node->key),
3367                                  vbases_p);
3368 }
3369
3370 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
3371    non-static data member of the type indicated by RLI.  BINFO is the
3372    binfo corresponding to the base subobject, OFFSETS maps offsets to
3373    types already located at those offsets.  This function determines
3374    the position of the DECL.  */
3375
3376 static void
3377 layout_nonempty_base_or_field (record_layout_info rli,
3378                                tree decl,
3379                                tree binfo,
3380                                splay_tree offsets)
3381 {
3382   tree offset = NULL_TREE;
3383   bool field_p;
3384   tree type;
3385
3386   if (binfo)
3387     {
3388       /* For the purposes of determining layout conflicts, we want to
3389          use the class type of BINFO; TREE_TYPE (DECL) will be the
3390          CLASSTYPE_AS_BASE version, which does not contain entries for
3391          zero-sized bases.  */
3392       type = TREE_TYPE (binfo);
3393       field_p = false;
3394     }
3395   else
3396     {
3397       type = TREE_TYPE (decl);
3398       field_p = true;
3399     }
3400
3401   /* Try to place the field.  It may take more than one try if we have
3402      a hard time placing the field without putting two objects of the
3403      same type at the same address.  */
3404   while (1)
3405     {
3406       struct record_layout_info_s old_rli = *rli;
3407
3408       /* Place this field.  */
3409       place_field (rli, decl);
3410       offset = byte_position (decl);
3411
3412       /* We have to check to see whether or not there is already
3413          something of the same type at the offset we're about to use.
3414          For example, consider:
3415
3416            struct S {};
3417            struct T : public S { int i; };
3418            struct U : public S, public T {};
3419
3420          Here, we put S at offset zero in U.  Then, we can't put T at
3421          offset zero -- its S component would be at the same address
3422          as the S we already allocated.  So, we have to skip ahead.
3423          Since all data members, including those whose type is an
3424          empty class, have nonzero size, any overlap can happen only
3425          with a direct or indirect base-class -- it can't happen with
3426          a data member.  */
3427       /* In a union, overlap is permitted; all members are placed at
3428          offset zero.  */
3429       if (TREE_CODE (rli->t) == UNION_TYPE)
3430         break;
3431       /* G++ 3.2 did not check for overlaps when placing a non-empty
3432          virtual base.  */
3433       if (!abi_version_at_least (2) && binfo && BINFO_VIRTUAL_P (binfo))
3434         break;
3435       if (layout_conflict_p (field_p ? type : binfo, offset,
3436                              offsets, field_p))
3437         {
3438           /* Strip off the size allocated to this field.  That puts us
3439              at the first place we could have put the field with
3440              proper alignment.  */
3441           *rli = old_rli;
3442
3443           /* Bump up by the alignment required for the type.  */
3444           rli->bitpos
3445             = size_binop (PLUS_EXPR, rli->bitpos,
3446                           bitsize_int (binfo
3447                                        ? CLASSTYPE_ALIGN (type)
3448                                        : TYPE_ALIGN (type)));
3449           normalize_rli (rli);
3450         }
3451       else
3452         /* There was no conflict.  We're done laying out this field.  */
3453         break;
3454     }
3455
3456   /* Now that we know where it will be placed, update its
3457      BINFO_OFFSET.  */
3458   if (binfo && CLASS_TYPE_P (BINFO_TYPE (binfo)))
3459     /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
3460        this point because their BINFO_OFFSET is copied from another
3461        hierarchy.  Therefore, we may not need to add the entire
3462        OFFSET.  */
3463     propagate_binfo_offsets (binfo,
3464                              size_diffop (convert (ssizetype, offset),
3465                                           convert (ssizetype,
3466                                                    BINFO_OFFSET (binfo))));
3467 }
3468
3469 /* Returns true if TYPE is empty and OFFSET is nonzero.  */
3470
3471 static int
3472 empty_base_at_nonzero_offset_p (tree type,
3473                                 tree offset,
3474                                 splay_tree offsets ATTRIBUTE_UNUSED)
3475 {
3476   return is_empty_class (type) && !integer_zerop (offset);
3477 }
3478
3479 /* Layout the empty base BINFO.  EOC indicates the byte currently just
3480    past the end of the class, and should be correctly aligned for a
3481    class of the type indicated by BINFO; OFFSETS gives the offsets of
3482    the empty bases allocated so far. T is the most derived
3483    type.  Return nonzero iff we added it at the end.  */
3484
3485 static bool
3486 layout_empty_base (tree binfo, tree eoc, splay_tree offsets)
3487 {
3488   tree alignment;
3489   tree basetype = BINFO_TYPE (binfo);
3490   bool atend = false;
3491
3492   /* This routine should only be used for empty classes.  */
3493   gcc_assert (is_empty_class (basetype));
3494   alignment = ssize_int (CLASSTYPE_ALIGN_UNIT (basetype));
3495
3496   if (!integer_zerop (BINFO_OFFSET (binfo)))
3497     {
3498       if (abi_version_at_least (2))
3499         propagate_binfo_offsets
3500           (binfo, size_diffop (size_zero_node, BINFO_OFFSET (binfo)));
3501       else
3502         warning (OPT_Wabi,
3503                  "offset of empty base %qT may not be ABI-compliant and may"
3504                  "change in a future version of GCC",
3505                  BINFO_TYPE (binfo));
3506     }
3507
3508   /* This is an empty base class.  We first try to put it at offset
3509      zero.  */
3510   if (layout_conflict_p (binfo,
3511                          BINFO_OFFSET (binfo),
3512                          offsets,
3513                          /*vbases_p=*/0))
3514     {
3515       /* That didn't work.  Now, we move forward from the next
3516          available spot in the class.  */
3517       atend = true;
3518       propagate_binfo_offsets (binfo, convert (ssizetype, eoc));
3519       while (1)
3520         {
3521           if (!layout_conflict_p (binfo,
3522                                   BINFO_OFFSET (binfo),
3523                                   offsets,
3524                                   /*vbases_p=*/0))
3525             /* We finally found a spot where there's no overlap.  */
3526             break;
3527
3528           /* There's overlap here, too.  Bump along to the next spot.  */
3529           propagate_binfo_offsets (binfo, alignment);
3530         }
3531     }
3532   return atend;
3533 }
3534
3535 /* Layout the base given by BINFO in the class indicated by RLI.
3536    *BASE_ALIGN is a running maximum of the alignments of
3537    any base class.  OFFSETS gives the location of empty base
3538    subobjects.  T is the most derived type.  Return nonzero if the new
3539    object cannot be nearly-empty.  A new FIELD_DECL is inserted at
3540    *NEXT_FIELD, unless BINFO is for an empty base class.
3541
3542    Returns the location at which the next field should be inserted.  */
3543
3544 static tree *
3545 build_base_field (record_layout_info rli, tree binfo,
3546                   splay_tree offsets, tree *next_field)
3547 {
3548   tree t = rli->t;
3549   tree basetype = BINFO_TYPE (binfo);
3550
3551   if (!COMPLETE_TYPE_P (basetype))
3552     /* This error is now reported in xref_tag, thus giving better
3553        location information.  */
3554     return next_field;
3555
3556   /* Place the base class.  */
3557   if (!is_empty_class (basetype))
3558     {
3559       tree decl;
3560
3561       /* The containing class is non-empty because it has a non-empty
3562          base class.  */
3563       CLASSTYPE_EMPTY_P (t) = 0;
3564
3565       /* Create the FIELD_DECL.  */
3566       decl = build_decl (FIELD_DECL, NULL_TREE, CLASSTYPE_AS_BASE (basetype));
3567       DECL_ARTIFICIAL (decl) = 1;
3568       DECL_IGNORED_P (decl) = 1;
3569       DECL_FIELD_CONTEXT (decl) = t;
3570       DECL_SIZE (decl) = CLASSTYPE_SIZE (basetype);
3571       DECL_SIZE_UNIT (decl) = CLASSTYPE_SIZE_UNIT (basetype);
3572       DECL_ALIGN (decl) = CLASSTYPE_ALIGN (basetype);
3573       DECL_USER_ALIGN (decl) = CLASSTYPE_USER_ALIGN (basetype);
3574       DECL_MODE (decl) = TYPE_MODE (basetype);
3575       DECL_FIELD_IS_BASE (decl) = 1;
3576
3577       /* Try to place the field.  It may take more than one try if we
3578          have a hard time placing the field without putting two
3579          objects of the same type at the same address.  */
3580       layout_nonempty_base_or_field (rli, decl, binfo, offsets);
3581       /* Add the new FIELD_DECL to the list of fields for T.  */
3582       TREE_CHAIN (decl) = *next_field;
3583       *next_field = decl;
3584       next_field = &TREE_CHAIN (decl);
3585     }
3586   else
3587     {
3588       tree eoc;
3589       bool atend;
3590
3591       /* On some platforms (ARM), even empty classes will not be
3592          byte-aligned.  */
3593       eoc = round_up (rli_size_unit_so_far (rli),
3594                       CLASSTYPE_ALIGN_UNIT (basetype));
3595       atend = layout_empty_base (binfo, eoc, offsets);
3596       /* A nearly-empty class "has no proper base class that is empty,
3597          not morally virtual, and at an offset other than zero."  */
3598       if (!BINFO_VIRTUAL_P (binfo) && CLASSTYPE_NEARLY_EMPTY_P (t))
3599         {
3600           if (atend)
3601             CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
3602           /* The check above (used in G++ 3.2) is insufficient because
3603              an empty class placed at offset zero might itself have an
3604              empty base at a nonzero offset.  */
3605           else if (walk_subobject_offsets (basetype,
3606                                            empty_base_at_nonzero_offset_p,
3607                                            size_zero_node,
3608                                            /*offsets=*/NULL,
3609                                            /*max_offset=*/NULL_TREE,
3610                                            /*vbases_p=*/true))
3611             {
3612               if (abi_version_at_least (2))
3613                 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
3614               else
3615                 warning (OPT_Wabi,
3616                          "class %qT will be considered nearly empty in a "
3617                          "future version of GCC", t);
3618             }
3619         }
3620
3621       /* We do not create a FIELD_DECL for empty base classes because
3622          it might overlap some other field.  We want to be able to
3623          create CONSTRUCTORs for the class by iterating over the
3624          FIELD_DECLs, and the back end does not handle overlapping
3625          FIELD_DECLs.  */
3626
3627       /* An empty virtual base causes a class to be non-empty
3628          -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
3629          here because that was already done when the virtual table
3630          pointer was created.  */
3631     }
3632
3633   /* Record the offsets of BINFO and its base subobjects.  */
3634   record_subobject_offsets (binfo,
3635                             BINFO_OFFSET (binfo),
3636                             offsets,
3637                             /*is_data_member=*/false);
3638
3639   return next_field;
3640 }
3641
3642 /* Layout all of the non-virtual base classes.  Record empty
3643    subobjects in OFFSETS.  T is the most derived type.  Return nonzero
3644    if the type cannot be nearly empty.  The fields created
3645    corresponding to the base classes will be inserted at
3646    *NEXT_FIELD.  */
3647
3648 static void
3649 build_base_fields (record_layout_info rli,
3650                    splay_tree offsets, tree *next_field)
3651 {
3652   /* Chain to hold all the new FIELD_DECLs which stand in for base class
3653      subobjects.  */
3654   tree t = rli->t;
3655   int n_baseclasses = BINFO_N_BASE_BINFOS (TYPE_BINFO (t));
3656   int i;
3657
3658   /* The primary base class is always allocated first.  */
3659   if (CLASSTYPE_HAS_PRIMARY_BASE_P (t))
3660     next_field = build_base_field (rli, CLASSTYPE_PRIMARY_BINFO (t),
3661                                    offsets, next_field);
3662
3663   /* Now allocate the rest of the bases.  */
3664   for (i = 0; i < n_baseclasses; ++i)
3665     {
3666       tree base_binfo;
3667
3668       base_binfo = BINFO_BASE_BINFO (TYPE_BINFO (t), i);
3669
3670       /* The primary base was already allocated above, so we don't
3671          need to allocate it again here.  */
3672       if (base_binfo == CLASSTYPE_PRIMARY_BINFO (t))
3673         continue;
3674
3675       /* Virtual bases are added at the end (a primary virtual base
3676          will have already been added).  */
3677       if (BINFO_VIRTUAL_P (base_binfo))
3678         continue;
3679
3680       next_field = build_base_field (rli, base_binfo,
3681                                      offsets, next_field);
3682     }
3683 }
3684
3685 /* Go through the TYPE_METHODS of T issuing any appropriate
3686    diagnostics, figuring out which methods override which other
3687    methods, and so forth.  */
3688
3689 static void
3690 check_methods (tree t)
3691 {
3692   tree x;
3693
3694   for (x = TYPE_METHODS (t); x; x = TREE_CHAIN (x))
3695     {
3696       check_for_override (x, t);
3697       if (DECL_PURE_VIRTUAL_P (x) && ! DECL_VINDEX (x))
3698         error ("initializer specified for non-virtual method %q+D", x);
3699       /* The name of the field is the original field name
3700          Save this in auxiliary field for later overloading.  */
3701       if (DECL_VINDEX (x))
3702         {
3703           TYPE_POLYMORPHIC_P (t) = 1;
3704           if (DECL_PURE_VIRTUAL_P (x))
3705             VEC_safe_push (tree, gc, CLASSTYPE_PURE_VIRTUALS (t), x);
3706         }
3707       /* All user-declared destructors are non-trivial.  */
3708       if (DECL_DESTRUCTOR_P (x))
3709         TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t) = 1;
3710     }
3711 }
3712
3713 /* FN is a constructor or destructor.  Clone the declaration to create
3714    a specialized in-charge or not-in-charge version, as indicated by
3715    NAME.  */
3716
3717 static tree
3718 build_clone (tree fn, tree name)
3719 {
3720   tree parms;
3721   tree clone;
3722
3723   /* Copy the function.  */
3724   clone = copy_decl (fn);
3725   /* Remember where this function came from.  */
3726   DECL_CLONED_FUNCTION (clone) = fn;
3727   DECL_ABSTRACT_ORIGIN (clone) = fn;
3728   /* Reset the function name.  */
3729   DECL_NAME (clone) = name;
3730   SET_DECL_ASSEMBLER_NAME (clone, NULL_TREE);
3731   /* There's no pending inline data for this function.  */
3732   DECL_PENDING_INLINE_INFO (clone) = NULL;
3733   DECL_PENDING_INLINE_P (clone) = 0;
3734   /* And it hasn't yet been deferred.  */
3735   DECL_DEFERRED_FN (clone) = 0;
3736
3737   /* The base-class destructor is not virtual.  */
3738   if (name == base_dtor_identifier)
3739     {
3740       DECL_VIRTUAL_P (clone) = 0;
3741       if (TREE_CODE (clone) != TEMPLATE_DECL)
3742         DECL_VINDEX (clone) = NULL_TREE;
3743     }
3744
3745   /* If there was an in-charge parameter, drop it from the function
3746      type.  */
3747   if (DECL_HAS_IN_CHARGE_PARM_P (clone))
3748     {
3749       tree basetype;
3750       tree parmtypes;
3751       tree exceptions;
3752
3753       exceptions = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (clone));
3754       basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (clone));
3755       parmtypes = TYPE_ARG_TYPES (TREE_TYPE (clone));
3756       /* Skip the `this' parameter.  */
3757       parmtypes = TREE_CHAIN (parmtypes);
3758       /* Skip the in-charge parameter.  */
3759       parmtypes = TREE_CHAIN (parmtypes);
3760       /* And the VTT parm, in a complete [cd]tor.  */
3761       if (DECL_HAS_VTT_PARM_P (fn)
3762           && ! DECL_NEEDS_VTT_PARM_P (clone))
3763         parmtypes = TREE_CHAIN (parmtypes);
3764        /* If this is subobject constructor or destructor, add the vtt
3765          parameter.  */
3766       TREE_TYPE (clone)
3767         = build_method_type_directly (basetype,
3768                                       TREE_TYPE (TREE_TYPE (clone)),
3769                                       parmtypes);
3770       if (exceptions)
3771         TREE_TYPE (clone) = build_exception_variant (TREE_TYPE (clone),
3772                                                      exceptions);
3773       TREE_TYPE (clone)
3774         = cp_build_type_attribute_variant (TREE_TYPE (clone),
3775                                            TYPE_ATTRIBUTES (TREE_TYPE (fn)));
3776     }
3777
3778   /* Copy the function parameters.  But, DECL_ARGUMENTS on a TEMPLATE_DECL
3779      aren't function parameters; those are the template parameters.  */
3780   if (TREE_CODE (clone) != TEMPLATE_DECL)
3781     {
3782       DECL_ARGUMENTS (clone) = copy_list (DECL_ARGUMENTS (clone));
3783       /* Remove the in-charge parameter.  */
3784       if (DECL_HAS_IN_CHARGE_PARM_P (clone))
3785         {
3786           TREE_CHAIN (DECL_ARGUMENTS (clone))
3787             = TREE_CHAIN (TREE_CHAIN (DECL_ARGUMENTS (clone)));
3788           DECL_HAS_IN_CHARGE_PARM_P (clone) = 0;
3789         }
3790       /* And the VTT parm, in a complete [cd]tor.  */
3791       if (DECL_HAS_VTT_PARM_P (fn))
3792         {
3793           if (DECL_NEEDS_VTT_PARM_P (clone))
3794             DECL_HAS_VTT_PARM_P (clone) = 1;
3795           else
3796             {
3797               TREE_CHAIN (DECL_ARGUMENTS (clone))
3798                 = TREE_CHAIN (TREE_CHAIN (DECL_ARGUMENTS (clone)));
3799               DECL_HAS_VTT_PARM_P (clone) = 0;
3800             }
3801         }
3802
3803       for (parms = DECL_ARGUMENTS (clone); parms; parms = TREE_CHAIN (parms))
3804         {
3805           DECL_CONTEXT (parms) = clone;
3806           cxx_dup_lang_specific_decl (parms);
3807         }
3808     }
3809
3810   /* Create the RTL for this function.  */
3811   SET_DECL_RTL (clone, NULL_RTX);
3812   rest_of_decl_compilation (clone, /*top_level=*/1, at_eof);
3813
3814   /* Make it easy to find the CLONE given the FN.  */
3815   TREE_CHAIN (clone) = TREE_CHAIN (fn);
3816   TREE_CHAIN (fn) = clone;
3817
3818   /* If this is a template, handle the DECL_TEMPLATE_RESULT as well.  */
3819   if (TREE_CODE (clone) == TEMPLATE_DECL)
3820     {
3821       tree result;
3822
3823       DECL_TEMPLATE_RESULT (clone)
3824         = build_clone (DECL_TEMPLATE_RESULT (clone), name);
3825       result = DECL_TEMPLATE_RESULT (clone);
3826       DECL_TEMPLATE_INFO (result) = copy_node (DECL_TEMPLATE_INFO (result));
3827       DECL_TI_TEMPLATE (result) = clone;
3828     }
3829   else if (pch_file)
3830     note_decl_for_pch (clone);
3831
3832   return clone;
3833 }
3834
3835 /* Produce declarations for all appropriate clones of FN.  If
3836    UPDATE_METHOD_VEC_P is nonzero, the clones are added to the
3837    CLASTYPE_METHOD_VEC as well.  */
3838
3839 void
3840 clone_function_decl (tree fn, int update_method_vec_p)
3841 {
3842   tree clone;
3843
3844   /* Avoid inappropriate cloning.  */
3845   if (TREE_CHAIN (fn)
3846       && DECL_CLONED_FUNCTION (TREE_CHAIN (fn)))
3847     return;
3848
3849   if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn))
3850     {
3851       /* For each constructor, we need two variants: an in-charge version
3852          and a not-in-charge version.  */
3853       clone = build_clone (fn, complete_ctor_identifier);
3854       if (update_method_vec_p)
3855         add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3856       clone = build_clone (fn, base_ctor_identifier);
3857       if (update_method_vec_p)
3858         add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3859     }
3860   else
3861     {
3862       gcc_assert (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn));
3863
3864       /* For each destructor, we need three variants: an in-charge
3865          version, a not-in-charge version, and an in-charge deleting
3866          version.  We clone the deleting version first because that
3867          means it will go second on the TYPE_METHODS list -- and that
3868          corresponds to the correct layout order in the virtual
3869          function table.
3870
3871          For a non-virtual destructor, we do not build a deleting
3872          destructor.  */
3873       if (DECL_VIRTUAL_P (fn))
3874         {
3875           clone = build_clone (fn, deleting_dtor_identifier);
3876           if (update_method_vec_p)
3877             add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3878         }
3879       clone = build_clone (fn, complete_dtor_identifier);
3880       if (update_method_vec_p)
3881         add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3882       clone = build_clone (fn, base_dtor_identifier);
3883       if (update_method_vec_p)
3884         add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3885     }
3886
3887   /* Note that this is an abstract function that is never emitted.  */
3888   DECL_ABSTRACT (fn) = 1;
3889 }
3890
3891 /* DECL is an in charge constructor, which is being defined. This will
3892    have had an in class declaration, from whence clones were
3893    declared. An out-of-class definition can specify additional default
3894    arguments. As it is the clones that are involved in overload
3895    resolution, we must propagate the information from the DECL to its
3896    clones.  */
3897
3898 void
3899 adjust_clone_args (tree decl)
3900 {
3901   tree clone;
3902
3903   for (clone = TREE_CHAIN (decl); clone && DECL_CLONED_FUNCTION (clone);
3904        clone = TREE_CHAIN (clone))
3905     {
3906       tree orig_clone_parms = TYPE_ARG_TYPES (TREE_TYPE (clone));
3907       tree orig_decl_parms = TYPE_ARG_TYPES (TREE_TYPE (decl));
3908       tree decl_parms, clone_parms;
3909
3910       clone_parms = orig_clone_parms;
3911
3912       /* Skip the 'this' parameter.  */
3913       orig_clone_parms = TREE_CHAIN (orig_clone_parms);
3914       orig_decl_parms = TREE_CHAIN (orig_decl_parms);
3915
3916       if (DECL_HAS_IN_CHARGE_PARM_P (decl))
3917         orig_decl_parms = TREE_CHAIN (orig_decl_parms);
3918       if (DECL_HAS_VTT_PARM_P (decl))
3919         orig_decl_parms = TREE_CHAIN (orig_decl_parms);
3920
3921       clone_parms = orig_clone_parms;
3922       if (DECL_HAS_VTT_PARM_P (clone))
3923         clone_parms = TREE_CHAIN (clone_parms);
3924
3925       for (decl_parms = orig_decl_parms; decl_parms;
3926            decl_parms = TREE_CHAIN (decl_parms),
3927              clone_parms = TREE_CHAIN (clone_parms))
3928         {
3929           gcc_assert (same_type_p (TREE_TYPE (decl_parms),
3930                                    TREE_TYPE (clone_parms)));
3931
3932           if (TREE_PURPOSE (decl_parms) && !TREE_PURPOSE (clone_parms))
3933             {
3934               /* A default parameter has been added. Adjust the
3935                  clone's parameters.  */
3936               tree exceptions = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (clone));
3937               tree basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (clone));
3938               tree type;
3939
3940               clone_parms = orig_decl_parms;
3941
3942               if (DECL_HAS_VTT_PARM_P (clone))
3943                 {
3944                   clone_parms = tree_cons (TREE_PURPOSE (orig_clone_parms),
3945                                            TREE_VALUE (orig_clone_parms),
3946                                            clone_parms);
3947                   TREE_TYPE (clone_parms) = TREE_TYPE (orig_clone_parms);
3948                 }
3949               type = build_method_type_directly (basetype,
3950                                                  TREE_TYPE (TREE_TYPE (clone)),
3951                                                  clone_parms);
3952               if (exceptions)
3953                 type = build_exception_variant (type, exceptions);
3954               TREE_TYPE (clone) = type;
3955
3956               clone_parms = NULL_TREE;
3957               break;
3958             }
3959         }
3960       gcc_assert (!clone_parms);
3961     }
3962 }
3963
3964 /* For each of the constructors and destructors in T, create an
3965    in-charge and not-in-charge variant.  */
3966
3967 static void
3968 clone_constructors_and_destructors (tree t)
3969 {
3970   tree fns;
3971
3972   /* If for some reason we don't have a CLASSTYPE_METHOD_VEC, we bail
3973      out now.  */
3974   if (!CLASSTYPE_METHOD_VEC (t))
3975     return;
3976
3977   for (fns = CLASSTYPE_CONSTRUCTORS (t); fns; fns = OVL_NEXT (fns))
3978     clone_function_decl (OVL_CURRENT (fns), /*update_method_vec_p=*/1);
3979   for (fns = CLASSTYPE_DESTRUCTORS (t); fns; fns = OVL_NEXT (fns))
3980     clone_function_decl (OVL_CURRENT (fns), /*update_method_vec_p=*/1);
3981 }
3982
3983 /* Remove all zero-width bit-fields from T.  */
3984
3985 static void
3986 remove_zero_width_bit_fields (tree t)
3987 {
3988   tree *fieldsp;
3989
3990   fieldsp = &TYPE_FIELDS (t);
3991   while (*fieldsp)
3992     {
3993       if (TREE_CODE (*fieldsp) == FIELD_DECL
3994           && DECL_C_BIT_FIELD (*fieldsp)
3995           && DECL_INITIAL (*fieldsp))
3996         *fieldsp = TREE_CHAIN (*fieldsp);
3997       else
3998         fieldsp = &TREE_CHAIN (*fieldsp);
3999     }
4000 }
4001
4002 /* Returns TRUE iff we need a cookie when dynamically allocating an
4003    array whose elements have the indicated class TYPE.  */
4004
4005 static bool
4006 type_requires_array_cookie (tree type)
4007 {
4008   tree fns;
4009   bool has_two_argument_delete_p = false;
4010
4011   gcc_assert (CLASS_TYPE_P (type));
4012
4013   /* If there's a non-trivial destructor, we need a cookie.  In order
4014      to iterate through the array calling the destructor for each
4015      element, we'll have to know how many elements there are.  */
4016   if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
4017     return true;
4018
4019   /* If the usual deallocation function is a two-argument whose second
4020      argument is of type `size_t', then we have to pass the size of
4021      the array to the deallocation function, so we will need to store
4022      a cookie.  */
4023   fns = lookup_fnfields (TYPE_BINFO (type),
4024                          ansi_opname (VEC_DELETE_EXPR),
4025                          /*protect=*/0);
4026   /* If there are no `operator []' members, or the lookup is
4027      ambiguous, then we don't need a cookie.  */
4028   if (!fns || fns == error_mark_node)
4029     return false;
4030   /* Loop through all of the functions.  */
4031   for (fns = BASELINK_FUNCTIONS (fns); fns; fns = OVL_NEXT (fns))
4032     {
4033       tree fn;
4034       tree second_parm;
4035
4036       /* Select the current function.  */
4037       fn = OVL_CURRENT (fns);
4038       /* See if this function is a one-argument delete function.  If
4039          it is, then it will be the usual deallocation function.  */
4040       second_parm = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fn)));
4041       if (second_parm == void_list_node)
4042         return false;
4043       /* Otherwise, if we have a two-argument function and the second
4044          argument is `size_t', it will be the usual deallocation
4045          function -- unless there is one-argument function, too.  */
4046       if (TREE_CHAIN (second_parm) == void_list_node
4047           && same_type_p (TREE_VALUE (second_parm), sizetype))
4048         has_two_argument_delete_p = true;
4049     }
4050
4051   return has_two_argument_delete_p;
4052 }
4053
4054 /* Check the validity of the bases and members declared in T.  Add any
4055    implicitly-generated functions (like copy-constructors and
4056    assignment operators).  Compute various flag bits (like
4057    CLASSTYPE_NON_POD_T) for T.  This routine works purely at the C++
4058    level: i.e., independently of the ABI in use.  */
4059
4060 static void
4061 check_bases_and_members (tree t)
4062 {
4063   /* Nonzero if the implicitly generated copy constructor should take
4064      a non-const reference argument.  */
4065   int cant_have_const_ctor;
4066   /* Nonzero if the implicitly generated assignment operator
4067      should take a non-const reference argument.  */
4068   int no_const_asn_ref;
4069   tree access_decls;
4070
4071   /* By default, we use const reference arguments and generate default
4072      constructors.  */
4073   cant_have_const_ctor = 0;
4074   no_const_asn_ref = 0;
4075
4076   /* Check all the base-classes.  */
4077   check_bases (t, &cant_have_const_ctor,
4078                &no_const_asn_ref);
4079
4080   /* Check all the method declarations.  */
4081   check_methods (t);
4082
4083   /* Check all the data member declarations.  We cannot call
4084      check_field_decls until we have called check_bases check_methods,
4085      as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
4086      being set appropriately.  */
4087   check_field_decls (t, &access_decls,
4088                      &cant_have_const_ctor,
4089                      &no_const_asn_ref);
4090
4091   /* A nearly-empty class has to be vptr-containing; a nearly empty
4092      class contains just a vptr.  */
4093   if (!TYPE_CONTAINS_VPTR_P (t))
4094     CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
4095
4096   /* Do some bookkeeping that will guide the generation of implicitly
4097      declared member functions.  */
4098   TYPE_HAS_COMPLEX_INIT_REF (t)
4099     |= (TYPE_HAS_INIT_REF (t) || TYPE_CONTAINS_VPTR_P (t));
4100   TYPE_NEEDS_CONSTRUCTING (t)
4101     |= (TYPE_HAS_CONSTRUCTOR (t) || TYPE_CONTAINS_VPTR_P (t));
4102   CLASSTYPE_NON_AGGREGATE (t)
4103     |= (TYPE_HAS_CONSTRUCTOR (t) || TYPE_POLYMORPHIC_P (t));
4104   CLASSTYPE_NON_POD_P (t)
4105     |= (CLASSTYPE_NON_AGGREGATE (t)
4106         || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
4107         || TYPE_HAS_ASSIGN_REF (t));
4108   TYPE_HAS_COMPLEX_ASSIGN_REF (t)
4109     |= TYPE_HAS_ASSIGN_REF (t) || TYPE_CONTAINS_VPTR_P (t);
4110
4111   /* Synthesize any needed methods.  */
4112   add_implicitly_declared_members (t,
4113                                    cant_have_const_ctor,
4114                                    no_const_asn_ref);
4115
4116   /* Create the in-charge and not-in-charge variants of constructors
4117      and destructors.  */
4118   clone_constructors_and_destructors (t);
4119
4120   /* Process the using-declarations.  */
4121   for (; access_decls; access_decls = TREE_CHAIN (access_decls))
4122     handle_using_decl (TREE_VALUE (access_decls), t);
4123
4124   /* Build and sort the CLASSTYPE_METHOD_VEC.  */
4125   finish_struct_methods (t);
4126
4127   /* Figure out whether or not we will need a cookie when dynamically
4128      allocating an array of this type.  */
4129   TYPE_LANG_SPECIFIC (t)->u.c.vec_new_uses_cookie
4130     = type_requires_array_cookie (t);
4131 }
4132
4133 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
4134    accordingly.  If a new vfield was created (because T doesn't have a
4135    primary base class), then the newly created field is returned.  It
4136    is not added to the TYPE_FIELDS list; it is the caller's
4137    responsibility to do that.  Accumulate declared virtual functions
4138    on VIRTUALS_P.  */
4139
4140 static tree
4141 create_vtable_ptr (tree t, tree* virtuals_p)
4142 {
4143   tree fn;
4144
4145   /* Collect the virtual functions declared in T.  */
4146   for (fn = TYPE_METHODS (t); fn; fn = TREE_CHAIN (fn))
4147     if (DECL_VINDEX (fn) && !DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn)
4148         && TREE_CODE (DECL_VINDEX (fn)) != INTEGER_CST)
4149       {
4150         tree new_virtual = make_node (TREE_LIST);
4151
4152         BV_FN (new_virtual) = fn;
4153         BV_DELTA (new_virtual) = integer_zero_node;
4154         BV_VCALL_INDEX (new_virtual) = NULL_TREE;
4155
4156         TREE_CHAIN (new_virtual) = *virtuals_p;
4157         *virtuals_p = new_virtual;
4158       }
4159
4160   /* If we couldn't find an appropriate base class, create a new field
4161      here.  Even if there weren't any new virtual functions, we might need a
4162      new virtual function table if we're supposed to include vptrs in
4163      all classes that need them.  */
4164   if (!TYPE_VFIELD (t) && (*virtuals_p || TYPE_CONTAINS_VPTR_P (t)))
4165     {
4166       /* We build this decl with vtbl_ptr_type_node, which is a
4167          `vtable_entry_type*'.  It might seem more precise to use
4168          `vtable_entry_type (*)[N]' where N is the number of virtual
4169          functions.  However, that would require the vtable pointer in
4170          base classes to have a different type than the vtable pointer
4171          in derived classes.  We could make that happen, but that
4172          still wouldn't solve all the problems.  In particular, the
4173          type-based alias analysis code would decide that assignments
4174          to the base class vtable pointer can't alias assignments to
4175          the derived class vtable pointer, since they have different
4176          types.  Thus, in a derived class destructor, where the base
4177          class constructor was inlined, we could generate bad code for
4178          setting up the vtable pointer.
4179
4180          Therefore, we use one type for all vtable pointers.  We still
4181          use a type-correct type; it's just doesn't indicate the array
4182          bounds.  That's better than using `void*' or some such; it's
4183          cleaner, and it let's the alias analysis code know that these
4184          stores cannot alias stores to void*!  */
4185       tree field;
4186
4187       field = build_decl (FIELD_DECL, get_vfield_name (t), vtbl_ptr_type_node);
4188       DECL_VIRTUAL_P (field) = 1;
4189       DECL_ARTIFICIAL (field) = 1;
4190       DECL_FIELD_CONTEXT (field) = t;
4191       DECL_FCONTEXT (field) = t;
4192
4193       TYPE_VFIELD (t) = field;
4194
4195       /* This class is non-empty.  */
4196       CLASSTYPE_EMPTY_P (t) = 0;
4197
4198       return field;
4199     }
4200
4201   return NULL_TREE;
4202 }
4203
4204 /* Fixup the inline function given by INFO now that the class is
4205    complete.  */
4206
4207 static void
4208 fixup_pending_inline (tree fn)
4209 {
4210   if (DECL_PENDING_INLINE_INFO (fn))
4211     {
4212       tree args = DECL_ARGUMENTS (fn);
4213       while (args)
4214         {
4215           DECL_CONTEXT (args) = fn;
4216           args = TREE_CHAIN (args);
4217         }
4218     }
4219 }
4220
4221 /* Fixup the inline methods and friends in TYPE now that TYPE is
4222    complete.  */
4223
4224 static void
4225 fixup_inline_methods (tree type)
4226 {
4227   tree method = TYPE_METHODS (type);
4228   VEC(tree,gc) *friends;
4229   unsigned ix;
4230
4231   if (method && TREE_CODE (method) == TREE_VEC)
4232     {
4233       if (TREE_VEC_ELT (method, 1))
4234         method = TREE_VEC_ELT (method, 1);
4235       else if (TREE_VEC_ELT (method, 0))
4236         method = TREE_VEC_ELT (method, 0);
4237       else
4238         method = TREE_VEC_ELT (method, 2);
4239     }
4240
4241   /* Do inline member functions.  */
4242   for (; method; method = TREE_CHAIN (method))
4243     fixup_pending_inline (method);
4244
4245   /* Do friends.  */
4246   for (friends = CLASSTYPE_INLINE_FRIENDS (type), ix = 0;
4247        VEC_iterate (tree, friends, ix, method); ix++)
4248     fixup_pending_inline (method);
4249   CLASSTYPE_INLINE_FRIENDS (type) = NULL;
4250 }
4251
4252 /* Add OFFSET to all base types of BINFO which is a base in the
4253    hierarchy dominated by T.
4254
4255    OFFSET, which is a type offset, is number of bytes.  */
4256
4257 static void
4258 propagate_binfo_offsets (tree binfo, tree offset)
4259 {
4260   int i;
4261   tree primary_binfo;
4262   tree base_binfo;
4263
4264   /* Update BINFO's offset.  */
4265   BINFO_OFFSET (binfo)
4266     = convert (sizetype,
4267                size_binop (PLUS_EXPR,
4268                            convert (ssizetype, BINFO_OFFSET (binfo)),
4269                            offset));
4270
4271   /* Find the primary base class.  */
4272   primary_binfo = get_primary_binfo (binfo);
4273
4274   if (primary_binfo && BINFO_INHERITANCE_CHAIN (primary_binfo) == binfo)
4275     propagate_binfo_offsets (primary_binfo, offset);
4276
4277   /* Scan all of the bases, pushing the BINFO_OFFSET adjust
4278      downwards.  */
4279   for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
4280     {
4281       /* Don't do the primary base twice.  */
4282       if (base_binfo == primary_binfo)
4283         continue;
4284
4285       if (BINFO_VIRTUAL_P (base_binfo))
4286         continue;
4287
4288       propagate_binfo_offsets (base_binfo, offset);
4289     }
4290 }
4291
4292 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T.  Update
4293    TYPE_ALIGN and TYPE_SIZE for T.  OFFSETS gives the location of
4294    empty subobjects of T.  */
4295
4296 static void
4297 layout_virtual_bases (record_layout_info rli, splay_tree offsets)
4298 {
4299   tree vbase;
4300   tree t = rli->t;
4301   bool first_vbase = true;
4302   tree *next_field;
4303
4304   if (BINFO_N_BASE_BINFOS (TYPE_BINFO (t)) == 0)
4305     return;
4306
4307   if (!abi_version_at_least(2))
4308     {
4309       /* In G++ 3.2, we incorrectly rounded the size before laying out
4310          the virtual bases.  */
4311       finish_record_layout (rli, /*free_p=*/false);
4312 #ifdef STRUCTURE_SIZE_BOUNDARY
4313       /* Packed structures don't need to have minimum size.  */
4314       if (! TYPE_PACKED (t))
4315         TYPE_ALIGN (t) = MAX (TYPE_ALIGN (t), (unsigned) STRUCTURE_SIZE_BOUNDARY);
4316 #endif
4317       rli->offset = TYPE_SIZE_UNIT (t);
4318       rli->bitpos = bitsize_zero_node;
4319       rli->record_align = TYPE_ALIGN (t);
4320     }
4321
4322   /* Find the last field.  The artificial fields created for virtual
4323      bases will go after the last extant field to date.  */
4324   next_field = &TYPE_FIELDS (t);
4325   while (*next_field)
4326     next_field = &TREE_CHAIN (*next_field);
4327
4328   /* Go through the virtual bases, allocating space for each virtual
4329      base that is not already a primary base class.  These are
4330      allocated in inheritance graph order.  */
4331   for (vbase = TYPE_BINFO (t); vbase; vbase = TREE_CHAIN (vbase))
4332     {
4333       if (!BINFO_VIRTUAL_P (vbase))
4334         continue;
4335
4336       if (!BINFO_PRIMARY_P (vbase))
4337         {
4338           tree basetype = TREE_TYPE (vbase);
4339
4340           /* This virtual base is not a primary base of any class in the
4341              hierarchy, so we have to add space for it.  */
4342           next_field = build_base_field (rli, vbase,
4343                                          offsets, next_field);
4344
4345           /* If the first virtual base might have been placed at a
4346              lower address, had we started from CLASSTYPE_SIZE, rather
4347              than TYPE_SIZE, issue a warning.  There can be both false
4348              positives and false negatives from this warning in rare
4349              cases; to deal with all the possibilities would probably
4350              require performing both layout algorithms and comparing
4351              the results which is not particularly tractable.  */
4352           if (warn_abi
4353               && first_vbase
4354               && (tree_int_cst_lt
4355                   (size_binop (CEIL_DIV_EXPR,
4356                                round_up (CLASSTYPE_SIZE (t),
4357                                          CLASSTYPE_ALIGN (basetype)),
4358                                bitsize_unit_node),
4359                    BINFO_OFFSET (vbase))))
4360             warning (OPT_Wabi,
4361                      "offset of virtual base %qT is not ABI-compliant and "
4362                      "may change in a future version of GCC",
4363                      basetype);
4364
4365           first_vbase = false;
4366         }
4367     }
4368 }
4369
4370 /* Returns the offset of the byte just past the end of the base class
4371    BINFO.  */
4372
4373 static tree
4374 end_of_base (tree binfo)
4375 {
4376   tree size;
4377
4378   if (is_empty_class (BINFO_TYPE (binfo)))
4379     /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
4380        allocate some space for it. It cannot have virtual bases, so
4381        TYPE_SIZE_UNIT is fine.  */
4382     size = TYPE_SIZE_UNIT (BINFO_TYPE (binfo));
4383   else
4384     size = CLASSTYPE_SIZE_UNIT (BINFO_TYPE (binfo));
4385
4386   return size_binop (PLUS_EXPR, BINFO_OFFSET (binfo), size);
4387 }
4388
4389 /* Returns the offset of the byte just past the end of the base class
4390    with the highest offset in T.  If INCLUDE_VIRTUALS_P is zero, then
4391    only non-virtual bases are included.  */
4392
4393 static tree
4394 end_of_class (tree t, int include_virtuals_p)
4395 {
4396   tree result = size_zero_node;
4397   VEC(tree,gc) *vbases;
4398   tree binfo;
4399   tree base_binfo;
4400   tree offset;
4401   int i;
4402
4403   for (binfo = TYPE_BINFO (t), i = 0;
4404        BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
4405     {
4406       if (!include_virtuals_p
4407           && BINFO_VIRTUAL_P (base_binfo)
4408           && (!BINFO_PRIMARY_P (base_binfo)
4409               || BINFO_INHERITANCE_CHAIN (base_binfo) != TYPE_BINFO (t)))
4410         continue;
4411
4412       offset = end_of_base (base_binfo);
4413       if (INT_CST_LT_UNSIGNED (result, offset))
4414         result = offset;
4415     }
4416
4417   /* G++ 3.2 did not check indirect virtual bases.  */
4418   if (abi_version_at_least (2) && include_virtuals_p)
4419     for (vbases = CLASSTYPE_VBASECLASSES (t), i = 0;
4420          VEC_iterate (tree, vbases, i, base_binfo); i++)
4421       {
4422         offset = end_of_base (base_binfo);
4423         if (INT_CST_LT_UNSIGNED (result, offset))
4424           result = offset;
4425       }
4426
4427   return result;
4428 }
4429
4430 /* Warn about bases of T that are inaccessible because they are
4431    ambiguous.  For example:
4432
4433      struct S {};
4434      struct T : public S {};
4435      struct U : public S, public T {};
4436
4437    Here, `(S*) new U' is not allowed because there are two `S'
4438    subobjects of U.  */
4439
4440 static void
4441 warn_about_ambiguous_bases (tree t)
4442 {
4443   int i;
4444   VEC(tree,gc) *vbases;
4445   tree basetype;
4446   tree binfo;
4447   tree base_binfo;
4448
4449   /* If there are no repeated bases, nothing can be ambiguous.  */
4450   if (!CLASSTYPE_REPEATED_BASE_P (t))
4451     return;
4452
4453   /* Check direct bases.  */
4454   for (binfo = TYPE_BINFO (t), i = 0;
4455        BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
4456     {
4457       basetype = BINFO_TYPE (base_binfo);
4458
4459       if (!lookup_base (t, basetype, ba_unique | ba_quiet, NULL))
4460         warning (0, "direct base %qT inaccessible in %qT due to ambiguity",
4461                  basetype, t);
4462     }
4463
4464   /* Check for ambiguous virtual bases.  */
4465   if (extra_warnings)
4466     for (vbases = CLASSTYPE_VBASECLASSES (t), i = 0;
4467          VEC_iterate (tree, vbases, i, binfo); i++)
4468       {
4469         basetype = BINFO_TYPE (binfo);
4470
4471         if (!lookup_base (t, basetype, ba_unique | ba_quiet, NULL))
4472           warning (OPT_Wextra, "virtual base %qT inaccessible in %qT due to ambiguity",
4473                    basetype, t);
4474       }
4475 }
4476
4477 /* Compare two INTEGER_CSTs K1 and K2.  */
4478
4479 static int
4480 splay_tree_compare_integer_csts (splay_tree_key k1, splay_tree_key k2)
4481 {
4482   return tree_int_cst_compare ((tree) k1, (tree) k2);
4483 }
4484
4485 /* Increase the size indicated in RLI to account for empty classes
4486    that are "off the end" of the class.  */
4487
4488 static void
4489 include_empty_classes (record_layout_info rli)
4490 {
4491   tree eoc;
4492   tree rli_size;
4493
4494   /* It might be the case that we grew the class to allocate a
4495      zero-sized base class.  That won't be reflected in RLI, yet,
4496      because we are willing to overlay multiple bases at the same
4497      offset.  However, now we need to make sure that RLI is big enough
4498      to reflect the entire class.  */
4499   eoc = end_of_class (rli->t,
4500                       CLASSTYPE_AS_BASE (rli->t) != NULL_TREE);
4501   rli_size = rli_size_unit_so_far (rli);
4502   if (TREE_CODE (rli_size) == INTEGER_CST
4503       && INT_CST_LT_UNSIGNED (rli_size, eoc))
4504     {
4505       if (!abi_version_at_least (2))
4506         /* In version 1 of the ABI, the size of a class that ends with
4507            a bitfield was not rounded up to a whole multiple of a
4508            byte.  Because rli_size_unit_so_far returns only the number
4509            of fully allocated bytes, any extra bits were not included
4510            in the size.  */
4511         rli->bitpos = round_down (rli->bitpos, BITS_PER_UNIT);
4512       else
4513         /* The size should have been rounded to a whole byte.  */
4514         gcc_assert (tree_int_cst_equal
4515                     (rli->bitpos, round_down (rli->bitpos, BITS_PER_UNIT)));
4516       rli->bitpos
4517         = size_binop (PLUS_EXPR,
4518                       rli->bitpos,
4519                       size_binop (MULT_EXPR,
4520                                   convert (bitsizetype,
4521                                            size_binop (MINUS_EXPR,
4522                                                        eoc, rli_size)),
4523                                   bitsize_int (BITS_PER_UNIT)));
4524       normalize_rli (rli);
4525     }
4526 }
4527
4528 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T.  Calculate
4529    BINFO_OFFSETs for all of the base-classes.  Position the vtable
4530    pointer.  Accumulate declared virtual functions on VIRTUALS_P.  */
4531
4532 static void
4533 layout_class_type (tree t, tree *virtuals_p)
4534 {
4535   tree non_static_data_members;
4536   tree field;
4537   tree vptr;
4538   record_layout_info rli;
4539   /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
4540      types that appear at that offset.  */
4541   splay_tree empty_base_offsets;
4542   /* True if the last field layed out was a bit-field.  */
4543   bool last_field_was_bitfield = false;
4544   /* The location at which the next field should be inserted.  */
4545   tree *next_field;
4546   /* T, as a base class.  */
4547   tree base_t;
4548
4549   /* Keep track of the first non-static data member.  */
4550   non_static_data_members = TYPE_FIELDS (t);
4551
4552   /* Start laying out the record.  */
4553   rli = start_record_layout (t);
4554
4555   /* Mark all the primary bases in the hierarchy.  */
4556   determine_primary_bases (t);
4557
4558   /* Create a pointer to our virtual function table.  */
4559   vptr = create_vtable_ptr (t, virtuals_p);
4560
4561   /* The vptr is always the first thing in the class.  */
4562   if (vptr)
4563     {
4564       TREE_CHAIN (vptr) = TYPE_FIELDS (t);
4565       TYPE_FIELDS (t) = vptr;
4566       next_field = &TREE_CHAIN (vptr);
4567       place_field (rli, vptr);
4568     }
4569   else
4570     next_field = &TYPE_FIELDS (t);
4571
4572   /* Build FIELD_DECLs for all of the non-virtual base-types.  */
4573   empty_base_offsets = splay_tree_new (splay_tree_compare_integer_csts,
4574                                        NULL, NULL);
4575   build_base_fields (rli, empty_base_offsets, next_field);
4576
4577   /* Layout the non-static data members.  */
4578   for (field = non_static_data_members; field; field = TREE_CHAIN (field))
4579     {
4580       tree type;
4581       tree padding;
4582
4583       /* We still pass things that aren't non-static data members to
4584          the back-end, in case it wants to do something with them.  */
4585       if (TREE_CODE (field) != FIELD_DECL)
4586         {
4587           place_field (rli, field);
4588           /* If the static data member has incomplete type, keep track
4589              of it so that it can be completed later.  (The handling
4590              of pending statics in finish_record_layout is
4591              insufficient; consider:
4592
4593                struct S1;
4594                struct S2 { static S1 s1; };
4595
4596              At this point, finish_record_layout will be called, but
4597              S1 is still incomplete.)  */
4598           if (TREE_CODE (field) == VAR_DECL)
4599             {
4600               maybe_register_incomplete_var (field);
4601               /* The visibility of static data members is determined
4602                  at their point of declaration, not their point of
4603                  definition.  */
4604               determine_visibility (field);
4605             }
4606           continue;
4607         }
4608
4609       type = TREE_TYPE (field);
4610
4611       padding = NULL_TREE;
4612
4613       /* If this field is a bit-field whose width is greater than its
4614          type, then there are some special rules for allocating
4615          it.  */
4616       if (DECL_C_BIT_FIELD (field)
4617           && INT_CST_LT (TYPE_SIZE (type), DECL_SIZE (field)))
4618         {
4619           integer_type_kind itk;
4620           tree integer_type;
4621           bool was_unnamed_p = false;
4622           /* We must allocate the bits as if suitably aligned for the
4623              longest integer type that fits in this many bits.  type
4624              of the field.  Then, we are supposed to use the left over
4625              bits as additional padding.  */
4626           for (itk = itk_char; itk != itk_none; ++itk)
4627             if (INT_CST_LT (DECL_SIZE (field),
4628                             TYPE_SIZE (integer_types[itk])))
4629               break;
4630
4631           /* ITK now indicates a type that is too large for the
4632              field.  We have to back up by one to find the largest
4633              type that fits.  */
4634           integer_type = integer_types[itk - 1];
4635
4636           /* Figure out how much additional padding is required.  GCC
4637              3.2 always created a padding field, even if it had zero
4638              width.  */
4639           if (!abi_version_at_least (2)
4640               || INT_CST_LT (TYPE_SIZE (integer_type), DECL_SIZE (field)))
4641             {
4642               if (abi_version_at_least (2) && TREE_CODE (t) == UNION_TYPE)
4643                 /* In a union, the padding field must have the full width
4644                    of the bit-field; all fields start at offset zero.  */
4645                 padding = DECL_SIZE (field);
4646               else
4647                 {
4648                   if (TREE_CODE (t) == UNION_TYPE)
4649                     warning (OPT_Wabi, "size assigned to %qT may not be "
4650                              "ABI-compliant and may change in a future "
4651                              "version of GCC",
4652                              t);
4653                   padding = size_binop (MINUS_EXPR, DECL_SIZE (field),
4654                                         TYPE_SIZE (integer_type));
4655                 }
4656             }
4657 #ifdef PCC_BITFIELD_TYPE_MATTERS
4658           /* An unnamed bitfield does not normally affect the
4659              alignment of the containing class on a target where
4660              PCC_BITFIELD_TYPE_MATTERS.  But, the C++ ABI does not
4661              make any exceptions for unnamed bitfields when the
4662              bitfields are longer than their types.  Therefore, we
4663              temporarily give the field a name.  */
4664           if (PCC_BITFIELD_TYPE_MATTERS && !DECL_NAME (field))
4665             {
4666               was_unnamed_p = true;
4667               DECL_NAME (field) = make_anon_name ();
4668             }
4669 #endif
4670           DECL_SIZE (field) = TYPE_SIZE (integer_type);
4671           DECL_ALIGN (field) = TYPE_ALIGN (integer_type);
4672           DECL_USER_ALIGN (field) = TYPE_USER_ALIGN (integer_type);
4673           layout_nonempty_base_or_field (rli, field, NULL_TREE,
4674                                          empty_base_offsets);
4675           if (was_unnamed_p)
4676             DECL_NAME (field) = NULL_TREE;
4677           /* Now that layout has been performed, set the size of the
4678              field to the size of its declared type; the rest of the
4679              field is effectively invisible.  */
4680           DECL_SIZE (field) = TYPE_SIZE (type);
4681           /* We must also reset the DECL_MODE of the field.  */
4682           if (abi_version_at_least (2))
4683             DECL_MODE (field) = TYPE_MODE (type);
4684           else if (warn_abi
4685                    && DECL_MODE (field) != TYPE_MODE (type))
4686             /* Versions of G++ before G++ 3.4 did not reset the
4687                DECL_MODE.  */
4688             warning (OPT_Wabi,
4689                      "the offset of %qD may not be ABI-compliant and may "
4690                      "change in a future version of GCC", field);
4691         }
4692       else
4693         layout_nonempty_base_or_field (rli, field, NULL_TREE,
4694                                        empty_base_offsets);
4695
4696       /* Remember the location of any empty classes in FIELD.  */
4697       if (abi_version_at_least (2))
4698         record_subobject_offsets (TREE_TYPE (field),
4699                                   byte_position(field),
4700                                   empty_base_offsets,
4701                                   /*is_data_member=*/true);
4702
4703       /* If a bit-field does not immediately follow another bit-field,
4704          and yet it starts in the middle of a byte, we have failed to
4705          comply with the ABI.  */
4706       if (warn_abi
4707           && DECL_C_BIT_FIELD (field)
4708           /* The TREE_NO_WARNING flag gets set by Objective-C when
4709              laying out an Objective-C class.  The ObjC ABI differs
4710              from the C++ ABI, and so we do not want a warning
4711              here.  */
4712           && !TREE_NO_WARNING (field)
4713           && !last_field_was_bitfield
4714           && !integer_zerop (size_binop (TRUNC_MOD_EXPR,
4715                                          DECL_FIELD_BIT_OFFSET (field),
4716                                          bitsize_unit_node)))
4717         warning (OPT_Wabi, "offset of %q+D is not ABI-compliant and may "
4718                  "change in a future version of GCC", field);
4719
4720       /* G++ used to use DECL_FIELD_OFFSET as if it were the byte
4721          offset of the field.  */
4722       if (warn_abi
4723           && !tree_int_cst_equal (DECL_FIELD_OFFSET (field),
4724                                   byte_position (field))
4725           && contains_empty_class_p (TREE_TYPE (field)))
4726         warning (OPT_Wabi, "%q+D contains empty classes which may cause base "
4727                  "classes to be placed at different locations in a "
4728                  "future version of GCC", field);
4729
4730       /* The middle end uses the type of expressions to determine the
4731          possible range of expression values.  In order to optimize
4732          "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
4733          must be made aware of the width of "i", via its type.
4734
4735          Because C++ does not have integer types of arbitrary width,
4736          we must (for the purposes of the front end) convert from the
4737          type assigned here to the declared type of the bitfield
4738          whenever a bitfield expression is used as an rvalue.
4739          Similarly, when assigning a value to a bitfield, the value
4740          must be converted to the type given the bitfield here.  */
4741       if (DECL_C_BIT_FIELD (field))
4742         {
4743           tree ftype;
4744           unsigned HOST_WIDE_INT width;
4745           ftype = TREE_TYPE (field);
4746           width = tree_low_cst (DECL_SIZE (field), /*unsignedp=*/1);
4747           if (width != TYPE_PRECISION (ftype))
4748             TREE_TYPE (field)
4749               = c_build_bitfield_integer_type (width,
4750                                                TYPE_UNSIGNED (ftype));
4751         }
4752
4753       /* If we needed additional padding after this field, add it
4754          now.  */
4755       if (padding)
4756         {
4757           tree padding_field;
4758
4759           padding_field = build_decl (FIELD_DECL,
4760                                       NULL_TREE,
4761                                       char_type_node);
4762           DECL_BIT_FIELD (padding_field) = 1;
4763           DECL_SIZE (padding_field) = padding;
4764           DECL_CONTEXT (padding_field) = t;
4765           DECL_ARTIFICIAL (padding_field) = 1;
4766           DECL_IGNORED_P (padding_field) = 1;
4767           layout_nonempty_base_or_field (rli, padding_field,
4768                                          NULL_TREE,
4769                                          empty_base_offsets);
4770         }
4771
4772       last_field_was_bitfield = DECL_C_BIT_FIELD (field);
4773     }
4774
4775   if (abi_version_at_least (2) && !integer_zerop (rli->bitpos))
4776     {
4777       /* Make sure that we are on a byte boundary so that the size of
4778          the class without virtual bases will always be a round number
4779          of bytes.  */
4780       rli->bitpos = round_up (rli->bitpos, BITS_PER_UNIT);
4781       normalize_rli (rli);
4782     }
4783
4784   /* G++ 3.2 does not allow virtual bases to be overlaid with tail
4785      padding.  */
4786   if (!abi_version_at_least (2))
4787     include_empty_classes(rli);
4788
4789   /* Delete all zero-width bit-fields from the list of fields.  Now
4790      that the type is laid out they are no longer important.  */
4791   remove_zero_width_bit_fields (t);
4792
4793   /* Create the version of T used for virtual bases.  We do not use
4794      make_aggr_type for this version; this is an artificial type.  For
4795      a POD type, we just reuse T.  */
4796   if (CLASSTYPE_NON_POD_P (t) || CLASSTYPE_EMPTY_P (t))
4797     {
4798       base_t = make_node (TREE_CODE (t));
4799
4800       /* Set the size and alignment for the new type.  In G++ 3.2, all
4801          empty classes were considered to have size zero when used as
4802          base classes.  */
4803       if (!abi_version_at_least (2) && CLASSTYPE_EMPTY_P (t))
4804         {
4805           TYPE_SIZE (base_t) = bitsize_zero_node;
4806           TYPE_SIZE_UNIT (base_t) = size_zero_node;
4807           if (warn_abi && !integer_zerop (rli_size_unit_so_far (rli)))
4808             warning (OPT_Wabi,
4809                      "layout of classes derived from empty class %qT "
4810                      "may change in a future version of GCC",
4811                      t);
4812         }
4813       else
4814         {
4815           tree eoc;
4816
4817           /* If the ABI version is not at least two, and the last
4818              field was a bit-field, RLI may not be on a byte
4819              boundary.  In particular, rli_size_unit_so_far might
4820              indicate the last complete byte, while rli_size_so_far
4821              indicates the total number of bits used.  Therefore,
4822              rli_size_so_far, rather than rli_size_unit_so_far, is
4823              used to compute TYPE_SIZE_UNIT.  */
4824           eoc = end_of_class (t, /*include_virtuals_p=*/0);
4825           TYPE_SIZE_UNIT (base_t)
4826             = size_binop (MAX_EXPR,
4827                           convert (sizetype,
4828                                    size_binop (CEIL_DIV_EXPR,
4829                                                rli_size_so_far (rli),
4830                                                bitsize_int (BITS_PER_UNIT))),
4831                           eoc);
4832           TYPE_SIZE (base_t)
4833             = size_binop (MAX_EXPR,
4834                           rli_size_so_far (rli),
4835                           size_binop (MULT_EXPR,
4836                                       convert (bitsizetype, eoc),
4837                                       bitsize_int (BITS_PER_UNIT)));
4838         }
4839       TYPE_ALIGN (base_t) = rli->record_align;
4840       TYPE_USER_ALIGN (base_t) = TYPE_USER_ALIGN (t);
4841
4842       /* Copy the fields from T.  */
4843       next_field = &TYPE_FIELDS (base_t);
4844       for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
4845         if (TREE_CODE (field) == FIELD_DECL)
4846           {
4847             *next_field = build_decl (FIELD_DECL,
4848                                       DECL_NAME (field),
4849                                       TREE_TYPE (field));
4850             DECL_CONTEXT (*next_field) = base_t;
4851             DECL_FIELD_OFFSET (*next_field) = DECL_FIELD_OFFSET (field);
4852             DECL_FIELD_BIT_OFFSET (*next_field)
4853               = DECL_FIELD_BIT_OFFSET (field);
4854             DECL_SIZE (*next_field) = DECL_SIZE (field);
4855             DECL_MODE (*next_field) = DECL_MODE (field);
4856             next_field = &TREE_CHAIN (*next_field);
4857           }
4858
4859       /* Record the base version of the type.  */
4860       CLASSTYPE_AS_BASE (t) = base_t;
4861       TYPE_CONTEXT (base_t) = t;
4862     }
4863   else
4864     CLASSTYPE_AS_BASE (t) = t;
4865
4866   /* Every empty class contains an empty class.  */
4867   if (CLASSTYPE_EMPTY_P (t))
4868     CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
4869
4870   /* Set the TYPE_DECL for this type to contain the right
4871      value for DECL_OFFSET, so that we can use it as part
4872      of a COMPONENT_REF for multiple inheritance.  */
4873   layout_decl (TYPE_MAIN_DECL (t), 0);
4874
4875   /* Now fix up any virtual base class types that we left lying
4876      around.  We must get these done before we try to lay out the
4877      virtual function table.  As a side-effect, this will remove the
4878      base subobject fields.  */
4879   layout_virtual_bases (rli, empty_base_offsets);
4880
4881   /* Make sure that empty classes are reflected in RLI at this
4882      point.  */
4883   include_empty_classes(rli);
4884
4885   /* Make sure not to create any structures with zero size.  */
4886   if (integer_zerop (rli_size_unit_so_far (rli)) && CLASSTYPE_EMPTY_P (t))
4887     place_field (rli,
4888                  build_decl (FIELD_DECL, NULL_TREE, char_type_node));
4889
4890   /* Let the back-end lay out the type.  */
4891   finish_record_layout (rli, /*free_p=*/true);
4892
4893   /* Warn about bases that can't be talked about due to ambiguity.  */
4894   warn_about_ambiguous_bases (t);
4895
4896   /* Now that we're done with layout, give the base fields the real types.  */
4897   for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
4898     if (DECL_ARTIFICIAL (field) && IS_FAKE_BASE_TYPE (TREE_TYPE (field)))
4899       TREE_TYPE (field) = TYPE_CONTEXT (TREE_TYPE (field));
4900
4901   /* Clean up.  */
4902   splay_tree_delete (empty_base_offsets);
4903
4904   if (CLASSTYPE_EMPTY_P (t)
4905       && tree_int_cst_lt (sizeof_biggest_empty_class,
4906                           TYPE_SIZE_UNIT (t)))
4907     sizeof_biggest_empty_class = TYPE_SIZE_UNIT (t);
4908 }
4909
4910 /* Determine the "key method" for the class type indicated by TYPE,
4911    and set CLASSTYPE_KEY_METHOD accordingly.  */
4912
4913 void
4914 determine_key_method (tree type)
4915 {
4916   tree method;
4917
4918   if (TYPE_FOR_JAVA (type)
4919       || processing_template_decl
4920       || CLASSTYPE_TEMPLATE_INSTANTIATION (type)
4921       || CLASSTYPE_INTERFACE_KNOWN (type))
4922     return;
4923
4924   /* The key method is the first non-pure virtual function that is not
4925      inline at the point of class definition.  On some targets the
4926      key function may not be inline; those targets should not call
4927      this function until the end of the translation unit.  */
4928   for (method = TYPE_METHODS (type); method != NULL_TREE;
4929        method = TREE_CHAIN (method))
4930     if (DECL_VINDEX (method) != NULL_TREE
4931         && ! DECL_DECLARED_INLINE_P (method)
4932         && ! DECL_PURE_VIRTUAL_P (method))
4933       {
4934         CLASSTYPE_KEY_METHOD (type) = method;
4935         break;
4936       }
4937
4938   return;
4939 }
4940
4941 /* Perform processing required when the definition of T (a class type)
4942    is complete.  */
4943
4944 void
4945 finish_struct_1 (tree t)
4946 {
4947   tree x;
4948   /* A TREE_LIST.  The TREE_VALUE of each node is a FUNCTION_DECL.  */
4949   tree virtuals = NULL_TREE;
4950   int n_fields = 0;
4951
4952   if (COMPLETE_TYPE_P (t))
4953     {
4954       gcc_assert (IS_AGGR_TYPE (t));
4955       error ("redefinition of %q#T", t);
4956       popclass ();
4957       return;
4958     }
4959
4960   /* If this type was previously laid out as a forward reference,
4961      make sure we lay it out again.  */
4962   TYPE_SIZE (t) = NULL_TREE;
4963   CLASSTYPE_PRIMARY_BINFO (t) = NULL_TREE;
4964
4965   fixup_inline_methods (t);
4966
4967   /* Make assumptions about the class; we'll reset the flags if
4968      necessary.  */
4969   CLASSTYPE_EMPTY_P (t) = 1;
4970   CLASSTYPE_NEARLY_EMPTY_P (t) = 1;
4971   CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 0;
4972
4973   /* Do end-of-class semantic processing: checking the validity of the
4974      bases and members and add implicitly generated methods.  */
4975   check_bases_and_members (t);
4976
4977   /* Find the key method.  */
4978   if (TYPE_CONTAINS_VPTR_P (t))
4979     {
4980       /* The Itanium C++ ABI permits the key method to be chosen when
4981          the class is defined -- even though the key method so
4982          selected may later turn out to be an inline function.  On
4983          some systems (such as ARM Symbian OS) the key method cannot
4984          be determined until the end of the translation unit.  On such
4985          systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
4986          will cause the class to be added to KEYED_CLASSES.  Then, in
4987          finish_file we will determine the key method.  */
4988       if (targetm.cxx.key_method_may_be_inline ())
4989         determine_key_method (t);
4990
4991       /* If a polymorphic class has no key method, we may emit the vtable
4992          in every translation unit where the class definition appears.  */
4993       if (CLASSTYPE_KEY_METHOD (t) == NULL_TREE)
4994         keyed_classes = tree_cons (NULL_TREE, t, keyed_classes);
4995     }
4996
4997   /* Layout the class itself.  */
4998   layout_class_type (t, &virtuals);
4999   if (CLASSTYPE_AS_BASE (t) != t)
5000     /* We use the base type for trivial assignments, and hence it
5001        needs a mode.  */
5002     compute_record_mode (CLASSTYPE_AS_BASE (t));
5003
5004   virtuals = modify_all_vtables (t, nreverse (virtuals));
5005
5006   /* If necessary, create the primary vtable for this class.  */
5007   if (virtuals || TYPE_CONTAINS_VPTR_P (t))
5008     {
5009       /* We must enter these virtuals into the table.  */
5010       if (!CLASSTYPE_HAS_PRIMARY_BASE_P (t))
5011         build_primary_vtable (NULL_TREE, t);
5012       else if (! BINFO_NEW_VTABLE_MARKED (TYPE_BINFO (t)))
5013         /* Here we know enough to change the type of our virtual
5014            function table, but we will wait until later this function.  */
5015         build_primary_vtable (CLASSTYPE_PRIMARY_BINFO (t), t);
5016     }
5017
5018   if (TYPE_CONTAINS_VPTR_P (t))
5019     {
5020       int vindex;
5021       tree fn;
5022
5023       if (BINFO_VTABLE (TYPE_BINFO (t)))
5024         gcc_assert (DECL_VIRTUAL_P (BINFO_VTABLE (TYPE_BINFO (t))));
5025       if (!CLASSTYPE_HAS_PRIMARY_BASE_P (t))
5026         gcc_assert (BINFO_VIRTUALS (TYPE_BINFO (t)) == NULL_TREE);
5027
5028       /* Add entries for virtual functions introduced by this class.  */
5029       BINFO_VIRTUALS (TYPE_BINFO (t))
5030         = chainon (BINFO_VIRTUALS (TYPE_BINFO (t)), virtuals);
5031
5032       /* Set DECL_VINDEX for all functions declared in this class.  */
5033       for (vindex = 0, fn = BINFO_VIRTUALS (TYPE_BINFO (t));
5034            fn;
5035            fn = TREE_CHAIN (fn),
5036              vindex += (TARGET_VTABLE_USES_DESCRIPTORS
5037                         ? TARGET_VTABLE_USES_DESCRIPTORS : 1))
5038         {
5039           tree fndecl = BV_FN (fn);
5040
5041           if (DECL_THUNK_P (fndecl))
5042             /* A thunk. We should never be calling this entry directly
5043                from this vtable -- we'd use the entry for the non
5044                thunk base function.  */
5045             DECL_VINDEX (fndecl) = NULL_TREE;
5046           else if (TREE_CODE (DECL_VINDEX (fndecl)) != INTEGER_CST)
5047             DECL_VINDEX (fndecl) = build_int_cst (NULL_TREE, vindex);
5048         }
5049     }
5050
5051   finish_struct_bits (t);
5052
5053   /* Complete the rtl for any static member objects of the type we're
5054      working on.  */
5055   for (x = TYPE_FIELDS (t); x; x = TREE_CHAIN (x))
5056     if (TREE_CODE (x) == VAR_DECL && TREE_STATIC (x)
5057         && same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (x)), t))
5058       DECL_MODE (x) = TYPE_MODE (t);
5059
5060   /* Done with FIELDS...now decide whether to sort these for
5061      faster lookups later.
5062
5063      We use a small number because most searches fail (succeeding
5064      ultimately as the search bores through the inheritance
5065      hierarchy), and we want this failure to occur quickly.  */
5066
5067   n_fields = count_fields (TYPE_FIELDS (t));
5068   if (n_fields > 7)
5069     {
5070       struct sorted_fields_type *field_vec = GGC_NEWVAR
5071          (struct sorted_fields_type,
5072           sizeof (struct sorted_fields_type) + n_fields * sizeof (tree));
5073       field_vec->len = n_fields;
5074       add_fields_to_record_type (TYPE_FIELDS (t), field_vec, 0);
5075       qsort (field_vec->elts, n_fields, sizeof (tree),
5076              field_decl_cmp);
5077       if (! DECL_LANG_SPECIFIC (TYPE_MAIN_DECL (t)))
5078         retrofit_lang_decl (TYPE_MAIN_DECL (t));
5079       DECL_SORTED_FIELDS (TYPE_MAIN_DECL (t)) = field_vec;
5080     }
5081
5082   /* Make the rtl for any new vtables we have created, and unmark
5083      the base types we marked.  */
5084   finish_vtbls (t);
5085
5086   /* Build the VTT for T.  */
5087   build_vtt (t);
5088
5089   /* This warning does not make sense for Java classes, since they
5090      cannot have destructors.  */
5091   if (!TYPE_FOR_JAVA (t) && warn_nonvdtor && TYPE_POLYMORPHIC_P (t))
5092     {
5093       tree dtor;
5094
5095       dtor = CLASSTYPE_DESTRUCTORS (t);
5096       /* Warn only if the dtor is non-private or the class has
5097          friends.  */
5098       if (/* An implicitly declared destructor is always public.  And,
5099              if it were virtual, we would have created it by now.  */
5100           !dtor
5101           || (!DECL_VINDEX (dtor)
5102               && (!TREE_PRIVATE (dtor)
5103                   || CLASSTYPE_FRIEND_CLASSES (t)
5104                   || DECL_FRIENDLIST (TYPE_MAIN_DECL (t)))))
5105         warning (0, "%q#T has virtual functions but non-virtual destructor",
5106                  t);
5107     }
5108
5109   complete_vars (t);
5110
5111   if (warn_overloaded_virtual)
5112     warn_hidden (t);
5113
5114   /* Class layout, assignment of virtual table slots, etc., is now
5115      complete.  Give the back end a chance to tweak the visibility of
5116      the class or perform any other required target modifications.  */
5117   targetm.cxx.adjust_class_at_definition (t);
5118
5119   maybe_suppress_debug_info (t);
5120
5121   dump_class_hierarchy (t);
5122
5123   /* Finish debugging output for this type.  */
5124   rest_of_type_compilation (t, ! LOCAL_CLASS_P (t));
5125 }
5126
5127 /* When T was built up, the member declarations were added in reverse
5128    order.  Rearrange them to declaration order.  */
5129
5130 void
5131 unreverse_member_declarations (tree t)
5132 {
5133   tree next;
5134   tree prev;
5135   tree x;
5136
5137   /* The following lists are all in reverse order.  Put them in
5138      declaration order now.  */
5139   TYPE_METHODS (t) = nreverse (TYPE_METHODS (t));
5140   CLASSTYPE_DECL_LIST (t) = nreverse (CLASSTYPE_DECL_LIST (t));
5141
5142   /* Actually, for the TYPE_FIELDS, only the non TYPE_DECLs are in
5143      reverse order, so we can't just use nreverse.  */
5144   prev = NULL_TREE;
5145   for (x = TYPE_FIELDS (t);
5146        x && TREE_CODE (x) != TYPE_DECL;
5147        x = next)
5148     {
5149       next = TREE_CHAIN (x);
5150       TREE_CHAIN (x) = prev;
5151       prev = x;
5152     }
5153   if (prev)
5154     {
5155       TREE_CHAIN (TYPE_FIELDS (t)) = x;
5156       if (prev)
5157         TYPE_FIELDS (t) = prev;
5158     }
5159 }
5160
5161 tree
5162 finish_struct (tree t, tree attributes)
5163 {
5164   location_t saved_loc = input_location;
5165
5166   /* Now that we've got all the field declarations, reverse everything
5167      as necessary.  */
5168   unreverse_member_declarations (t);
5169
5170   cplus_decl_attributes (&t, attributes, (int) ATTR_FLAG_TYPE_IN_PLACE);
5171
5172   /* Nadger the current location so that diagnostics point to the start of
5173      the struct, not the end.  */
5174   input_location = DECL_SOURCE_LOCATION (TYPE_NAME (t));
5175
5176   if (processing_template_decl)
5177     {
5178       tree x;
5179
5180       finish_struct_methods (t);
5181       TYPE_SIZE (t) = bitsize_zero_node;
5182       TYPE_SIZE_UNIT (t) = size_zero_node;
5183
5184       /* We need to emit an error message if this type was used as a parameter
5185          and it is an abstract type, even if it is a template. We construct
5186          a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
5187          account and we call complete_vars with this type, which will check
5188          the PARM_DECLS. Note that while the type is being defined,
5189          CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
5190          (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it.  */
5191       CLASSTYPE_PURE_VIRTUALS (t) = NULL;
5192       for (x = TYPE_METHODS (t); x; x = TREE_CHAIN (x))
5193         if (DECL_PURE_VIRTUAL_P (x))
5194           VEC_safe_push (tree, gc, CLASSTYPE_PURE_VIRTUALS (t), x);
5195       complete_vars (t);
5196     }
5197   else
5198     finish_struct_1 (t);
5199
5200   input_location = saved_loc;
5201
5202   TYPE_BEING_DEFINED (t) = 0;
5203
5204   if (current_class_type)
5205     popclass ();
5206   else
5207     error ("trying to finish struct, but kicked out due to previous parse errors");
5208
5209   if (processing_template_decl && at_function_scope_p ())
5210     add_stmt (build_min (TAG_DEFN, t));
5211
5212   return t;
5213 }
5214 \f
5215 /* Return the dynamic type of INSTANCE, if known.
5216    Used to determine whether the virtual function table is needed
5217    or not.
5218
5219    *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
5220    of our knowledge of its type.  *NONNULL should be initialized
5221    before this function is called.  */
5222
5223 static tree
5224 fixed_type_or_null (tree instance, int* nonnull, int* cdtorp)
5225 {
5226   switch (TREE_CODE (instance))
5227     {
5228     case INDIRECT_REF:
5229       if (POINTER_TYPE_P (TREE_TYPE (instance)))
5230         return NULL_TREE;
5231       else
5232         return fixed_type_or_null (TREE_OPERAND (instance, 0),
5233                                    nonnull, cdtorp);
5234
5235     case CALL_EXPR:
5236       /* This is a call to a constructor, hence it's never zero.  */
5237       if (TREE_HAS_CONSTRUCTOR (instance))
5238         {
5239           if (nonnull)
5240             *nonnull = 1;
5241           return TREE_TYPE (instance);
5242         }
5243       return NULL_TREE;
5244
5245     case SAVE_EXPR:
5246       /* This is a call to a constructor, hence it's never zero.  */
5247       if (TREE_HAS_CONSTRUCTOR (instance))
5248         {
5249           if (nonnull)
5250             *nonnull = 1;
5251           return TREE_TYPE (instance);
5252         }
5253       return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5254
5255     case PLUS_EXPR:
5256     case MINUS_EXPR:
5257       if (TREE_CODE (TREE_OPERAND (instance, 0)) == ADDR_EXPR)
5258         return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5259       if (TREE_CODE (TREE_OPERAND (instance, 1)) == INTEGER_CST)
5260         /* Propagate nonnull.  */
5261         return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5262       return NULL_TREE;
5263
5264     case NOP_EXPR:
5265     case CONVERT_EXPR:
5266       return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5267
5268     case ADDR_EXPR:
5269       instance = TREE_OPERAND (instance, 0);
5270       if (nonnull)
5271         {
5272           /* Just because we see an ADDR_EXPR doesn't mean we're dealing
5273              with a real object -- given &p->f, p can still be null.  */
5274           tree t = get_base_address (instance);
5275           /* ??? Probably should check DECL_WEAK here.  */
5276           if (t && DECL_P (t))
5277             *nonnull = 1;
5278         }
5279       return fixed_type_or_null (instance, nonnull, cdtorp);
5280
5281     case COMPONENT_REF:
5282       /* If this component is really a base class reference, then the field
5283          itself isn't definitive.  */
5284       if (DECL_FIELD_IS_BASE (TREE_OPERAND (instance, 1)))
5285         return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5286       return fixed_type_or_null (TREE_OPERAND (instance, 1), nonnull, cdtorp);
5287
5288     case VAR_DECL:
5289     case FIELD_DECL:
5290       if (TREE_CODE (TREE_TYPE (instance)) == ARRAY_TYPE
5291           && IS_AGGR_TYPE (TREE_TYPE (TREE_TYPE (instance))))
5292         {
5293           if (nonnull)
5294             *nonnull = 1;
5295           return TREE_TYPE (TREE_TYPE (instance));
5296         }
5297       /* fall through...  */
5298     case TARGET_EXPR:
5299     case PARM_DECL:
5300     case RESULT_DECL:
5301       if (IS_AGGR_TYPE (TREE_TYPE (instance)))
5302         {
5303           if (nonnull)
5304             *nonnull = 1;
5305           return TREE_TYPE (instance);
5306         }
5307       else if (instance == current_class_ptr)
5308         {
5309           if (nonnull)
5310             *nonnull = 1;
5311
5312           /* if we're in a ctor or dtor, we know our type.  */
5313           if (DECL_LANG_SPECIFIC (current_function_decl)
5314               && (DECL_CONSTRUCTOR_P (current_function_decl)
5315                   || DECL_DESTRUCTOR_P (current_function_decl)))
5316             {
5317               if (cdtorp)
5318                 *cdtorp = 1;
5319               return TREE_TYPE (TREE_TYPE (instance));
5320             }
5321         }
5322       else if (TREE_CODE (TREE_TYPE (instance)) == REFERENCE_TYPE)
5323         {
5324           /* Reference variables should be references to objects.  */
5325           if (nonnull)
5326             *nonnull = 1;
5327
5328           /* DECL_VAR_MARKED_P is used to prevent recursion; a
5329              variable's initializer may refer to the variable
5330              itself.  */
5331           if (TREE_CODE (instance) == VAR_DECL
5332               && DECL_INITIAL (instance)
5333               && !DECL_VAR_MARKED_P (instance))
5334             {
5335               tree type;
5336               DECL_VAR_MARKED_P (instance) = 1;
5337               type = fixed_type_or_null (DECL_INITIAL (instance),
5338                                          nonnull, cdtorp);
5339               DECL_VAR_MARKED_P (instance) = 0;
5340               return type;
5341             }
5342         }
5343       return NULL_TREE;
5344
5345     default:
5346       return NULL_TREE;
5347     }
5348 }
5349
5350 /* Return nonzero if the dynamic type of INSTANCE is known, and
5351    equivalent to the static type.  We also handle the case where
5352    INSTANCE is really a pointer. Return negative if this is a
5353    ctor/dtor. There the dynamic type is known, but this might not be
5354    the most derived base of the original object, and hence virtual
5355    bases may not be layed out according to this type.
5356
5357    Used to determine whether the virtual function table is needed
5358    or not.
5359
5360    *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
5361    of our knowledge of its type.  *NONNULL should be initialized
5362    before this function is called.  */
5363
5364 int
5365 resolves_to_fixed_type_p (tree instance, int* nonnull)
5366 {
5367   tree t = TREE_TYPE (instance);
5368   int cdtorp = 0;
5369
5370   tree fixed = fixed_type_or_null (instance, nonnull, &cdtorp);
5371   if (fixed == NULL_TREE)
5372     return 0;
5373   if (POINTER_TYPE_P (t))
5374     t = TREE_TYPE (t);
5375   if (!same_type_ignoring_top_level_qualifiers_p (t, fixed))
5376     return 0;
5377   return cdtorp ? -1 : 1;
5378 }
5379
5380 \f
5381 void
5382 init_class_processing (void)
5383 {
5384   current_class_depth = 0;
5385   current_class_stack_size = 10;
5386   current_class_stack
5387     = XNEWVEC (struct class_stack_node, current_class_stack_size);
5388   local_classes = VEC_alloc (tree, gc, 8);
5389   sizeof_biggest_empty_class = size_zero_node;
5390
5391   ridpointers[(int) RID_PUBLIC] = access_public_node;
5392   ridpointers[(int) RID_PRIVATE] = access_private_node;
5393   ridpointers[(int) RID_PROTECTED] = access_protected_node;
5394 }
5395
5396 /* Restore the cached PREVIOUS_CLASS_LEVEL.  */
5397
5398 static void
5399 restore_class_cache (void)
5400 {
5401   tree type;
5402
5403   /* We are re-entering the same class we just left, so we don't
5404      have to search the whole inheritance matrix to find all the
5405      decls to bind again.  Instead, we install the cached
5406      class_shadowed list and walk through it binding names.  */
5407   push_binding_level (previous_class_level);
5408   class_binding_level = previous_class_level;
5409   /* Restore IDENTIFIER_TYPE_VALUE.  */
5410   for (type = class_binding_level->type_shadowed;
5411        type;
5412        type = TREE_CHAIN (type))
5413     SET_IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (type), TREE_TYPE (type));
5414 }
5415
5416 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
5417    appropriate for TYPE.
5418
5419    So that we may avoid calls to lookup_name, we cache the _TYPE
5420    nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
5421
5422    For multiple inheritance, we perform a two-pass depth-first search
5423    of the type lattice.  */
5424
5425 void
5426 pushclass (tree type)
5427 {
5428   class_stack_node_t csn;
5429
5430   type = TYPE_MAIN_VARIANT (type);
5431
5432   /* Make sure there is enough room for the new entry on the stack.  */
5433   if (current_class_depth + 1 >= current_class_stack_size)
5434     {
5435       current_class_stack_size *= 2;
5436       current_class_stack
5437         = XRESIZEVEC (struct class_stack_node, current_class_stack,
5438                       current_class_stack_size);
5439     }
5440
5441   /* Insert a new entry on the class stack.  */
5442   csn = current_class_stack + current_class_depth;
5443   csn->name = current_class_name;
5444   csn->type = current_class_type;
5445   csn->access = current_access_specifier;
5446   csn->names_used = 0;
5447   csn->hidden = 0;
5448   current_class_depth++;
5449
5450   /* Now set up the new type.  */
5451   current_class_name = TYPE_NAME (type);
5452   if (TREE_CODE (current_class_name) == TYPE_DECL)
5453     current_class_name = DECL_NAME (current_class_name);
5454   current_class_type = type;
5455
5456   /* By default, things in classes are private, while things in
5457      structures or unions are public.  */
5458   current_access_specifier = (CLASSTYPE_DECLARED_CLASS (type)
5459                               ? access_private_node
5460                               : access_public_node);
5461
5462   if (previous_class_level
5463       && type != previous_class_level->this_entity
5464       && current_class_depth == 1)
5465     {
5466       /* Forcibly remove any old class remnants.  */
5467       invalidate_class_lookup_cache ();
5468     }
5469
5470   if (!previous_class_level
5471       || type != previous_class_level->this_entity
5472       || current_class_depth > 1)
5473     pushlevel_class ();
5474   else
5475     restore_class_cache ();
5476 }
5477
5478 /* When we exit a toplevel class scope, we save its binding level so
5479    that we can restore it quickly.  Here, we've entered some other
5480    class, so we must invalidate our cache.  */
5481
5482 void
5483 invalidate_class_lookup_cache (void)
5484 {
5485   previous_class_level = NULL;
5486 }
5487
5488 /* Get out of the current class scope. If we were in a class scope
5489    previously, that is the one popped to.  */
5490
5491 void
5492 popclass (void)
5493 {
5494   poplevel_class ();
5495
5496   current_class_depth--;
5497   current_class_name = current_class_stack[current_class_depth].name;
5498   current_class_type = current_class_stack[current_class_depth].type;
5499   current_access_specifier = current_class_stack[current_class_depth].access;
5500   if (current_class_stack[current_class_depth].names_used)
5501     splay_tree_delete (current_class_stack[current_class_depth].names_used);
5502 }
5503
5504 /* Mark the top of the class stack as hidden.  */
5505
5506 void
5507 push_class_stack (void)
5508 {
5509   if (current_class_depth)
5510     ++current_class_stack[current_class_depth - 1].hidden;
5511 }
5512
5513 /* Mark the top of the class stack as un-hidden.  */
5514
5515 void
5516 pop_class_stack (void)
5517 {
5518   if (current_class_depth)
5519     --current_class_stack[current_class_depth - 1].hidden;
5520 }
5521
5522 /* Returns 1 if the class type currently being defined is either T or
5523    a nested type of T.  */
5524
5525 bool
5526 currently_open_class (tree t)
5527 {
5528   int i;
5529
5530   /* We start looking from 1 because entry 0 is from global scope,
5531      and has no type.  */
5532   for (i = current_class_depth; i > 0; --i)
5533     {
5534       tree c;
5535       if (i == current_class_depth)
5536         c = current_class_type;
5537       else
5538         {
5539           if (current_class_stack[i].hidden)
5540             break;
5541           c = current_class_stack[i].type;
5542         }
5543       if (!c)
5544         continue;
5545       if (same_type_p (c, t))
5546         return true;
5547     }
5548   return false;
5549 }
5550
5551 /* If either current_class_type or one of its enclosing classes are derived
5552    from T, return the appropriate type.  Used to determine how we found
5553    something via unqualified lookup.  */
5554
5555 tree
5556 currently_open_derived_class (tree t)
5557 {
5558   int i;
5559
5560   /* The bases of a dependent type are unknown.  */
5561   if (dependent_type_p (t))
5562     return NULL_TREE;
5563
5564   if (!current_class_type)
5565     return NULL_TREE;
5566
5567   if (DERIVED_FROM_P (t, current_class_type))
5568     return current_class_type;
5569
5570   for (i = current_class_depth - 1; i > 0; --i)
5571     {
5572       if (current_class_stack[i].hidden)
5573         break;
5574       if (DERIVED_FROM_P (t, current_class_stack[i].type))
5575         return current_class_stack[i].type;
5576     }
5577
5578   return NULL_TREE;
5579 }
5580
5581 /* When entering a class scope, all enclosing class scopes' names with
5582    static meaning (static variables, static functions, types and
5583    enumerators) have to be visible.  This recursive function calls
5584    pushclass for all enclosing class contexts until global or a local
5585    scope is reached.  TYPE is the enclosed class.  */
5586
5587 void
5588 push_nested_class (tree type)
5589 {
5590   tree context;
5591
5592   /* A namespace might be passed in error cases, like A::B:C.  */
5593   if (type == NULL_TREE
5594       || type == error_mark_node
5595       || TREE_CODE (type) == NAMESPACE_DECL
5596       || ! IS_AGGR_TYPE (type)
5597       || TREE_CODE (type) == TEMPLATE_TYPE_PARM
5598       || TREE_CODE (type) == BOUND_TEMPLATE_TEMPLATE_PARM)
5599     return;
5600
5601   context = DECL_CONTEXT (TYPE_MAIN_DECL (type));
5602
5603   if (context && CLASS_TYPE_P (context))
5604     push_nested_class (context);
5605   pushclass (type);
5606 }
5607
5608 /* Undoes a push_nested_class call.  */
5609
5610 void
5611 pop_nested_class (void)
5612 {
5613   tree context = DECL_CONTEXT (TYPE_MAIN_DECL (current_class_type));
5614
5615   popclass ();
5616   if (context && CLASS_TYPE_P (context))
5617     pop_nested_class ();
5618 }
5619
5620 /* Returns the number of extern "LANG" blocks we are nested within.  */
5621
5622 int
5623 current_lang_depth (void)
5624 {
5625   return VEC_length (tree, current_lang_base);
5626 }
5627
5628 /* Set global variables CURRENT_LANG_NAME to appropriate value
5629    so that behavior of name-mangling machinery is correct.  */
5630
5631 void
5632 push_lang_context (tree name)
5633 {
5634   VEC_safe_push (tree, gc, current_lang_base, current_lang_name);
5635
5636   if (name == lang_name_cplusplus)
5637     {
5638       current_lang_name = name;
5639     }
5640   else if (name == lang_name_java)
5641     {
5642       current_lang_name = name;
5643       /* DECL_IGNORED_P is initially set for these types, to avoid clutter.
5644          (See record_builtin_java_type in decl.c.)  However, that causes
5645          incorrect debug entries if these types are actually used.
5646          So we re-enable debug output after extern "Java".  */
5647       DECL_IGNORED_P (TYPE_NAME (java_byte_type_node)) = 0;
5648       DECL_IGNORED_P (TYPE_NAME (java_short_type_node)) = 0;
5649       DECL_IGNORED_P (TYPE_NAME (java_int_type_node)) = 0;
5650       DECL_IGNORED_P (TYPE_NAME (java_long_type_node)) = 0;
5651       DECL_IGNORED_P (TYPE_NAME (java_float_type_node)) = 0;
5652       DECL_IGNORED_P (TYPE_NAME (java_double_type_node)) = 0;
5653       DECL_IGNORED_P (TYPE_NAME (java_char_type_node)) = 0;
5654       DECL_IGNORED_P (TYPE_NAME (java_boolean_type_node)) = 0;
5655     }
5656   else if (name == lang_name_c)
5657     {
5658       current_lang_name = name;
5659     }
5660   else
5661     error ("language string %<\"%E\"%> not recognized", name);
5662 }
5663
5664 /* Get out of the current language scope.  */
5665
5666 void
5667 pop_lang_context (void)
5668 {
5669   current_lang_name = VEC_pop (tree, current_lang_base);
5670 }
5671 \f
5672 /* Type instantiation routines.  */
5673
5674 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
5675    matches the TARGET_TYPE.  If there is no satisfactory match, return
5676    error_mark_node, and issue an error & warning messages under control
5677    of FLAGS.  Permit pointers to member function if FLAGS permits.  If
5678    TEMPLATE_ONLY, the name of the overloaded function was a
5679    template-id, and EXPLICIT_TARGS are the explicitly provided
5680    template arguments.  */
5681
5682 static tree
5683 resolve_address_of_overloaded_function (tree target_type,
5684                                         tree overload,
5685                                         tsubst_flags_t flags,
5686                                         bool template_only,
5687                                         tree explicit_targs)
5688 {
5689   /* Here's what the standard says:
5690
5691        [over.over]
5692
5693        If the name is a function template, template argument deduction
5694        is done, and if the argument deduction succeeds, the deduced
5695        arguments are used to generate a single template function, which
5696        is added to the set of overloaded functions considered.
5697
5698        Non-member functions and static member functions match targets of
5699        type "pointer-to-function" or "reference-to-function."  Nonstatic
5700        member functions match targets of type "pointer-to-member
5701        function;" the function type of the pointer to member is used to
5702        select the member function from the set of overloaded member
5703        functions.  If a nonstatic member function is selected, the
5704        reference to the overloaded function name is required to have the
5705        form of a pointer to member as described in 5.3.1.
5706
5707        If more than one function is selected, any template functions in
5708        the set are eliminated if the set also contains a non-template
5709        function, and any given template function is eliminated if the
5710        set contains a second template function that is more specialized
5711        than the first according to the partial ordering rules 14.5.5.2.
5712        After such eliminations, if any, there shall remain exactly one
5713        selected function.  */
5714
5715   int is_ptrmem = 0;
5716   int is_reference = 0;
5717   /* We store the matches in a TREE_LIST rooted here.  The functions
5718      are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
5719      interoperability with most_specialized_instantiation.  */
5720   tree matches = NULL_TREE;
5721   tree fn;
5722
5723   /* By the time we get here, we should be seeing only real
5724      pointer-to-member types, not the internal POINTER_TYPE to
5725      METHOD_TYPE representation.  */
5726   gcc_assert (TREE_CODE (target_type) != POINTER_TYPE
5727               || TREE_CODE (TREE_TYPE (target_type)) != METHOD_TYPE);
5728
5729   gcc_assert (is_overloaded_fn (overload));
5730
5731   /* Check that the TARGET_TYPE is reasonable.  */
5732   if (TYPE_PTRFN_P (target_type))
5733     /* This is OK.  */;
5734   else if (TYPE_PTRMEMFUNC_P (target_type))
5735     /* This is OK, too.  */
5736     is_ptrmem = 1;
5737   else if (TREE_CODE (target_type) == FUNCTION_TYPE)
5738     {
5739       /* This is OK, too.  This comes from a conversion to reference
5740          type.  */
5741       target_type = build_reference_type (target_type);
5742       is_reference = 1;
5743     }
5744   else
5745     {
5746       if (flags & tf_error)
5747         error ("cannot resolve overloaded function %qD based on"
5748                " conversion to type %qT",
5749                DECL_NAME (OVL_FUNCTION (overload)), target_type);
5750       return error_mark_node;
5751     }
5752
5753   /* If we can find a non-template function that matches, we can just
5754      use it.  There's no point in generating template instantiations
5755      if we're just going to throw them out anyhow.  But, of course, we
5756      can only do this when we don't *need* a template function.  */
5757   if (!template_only)
5758     {
5759       tree fns;
5760
5761       for (fns = overload; fns; fns = OVL_NEXT (fns))
5762         {
5763           tree fn = OVL_CURRENT (fns);
5764           tree fntype;
5765
5766           if (TREE_CODE (fn) == TEMPLATE_DECL)
5767             /* We're not looking for templates just yet.  */
5768             continue;
5769
5770           if ((TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
5771               != is_ptrmem)
5772             /* We're looking for a non-static member, and this isn't
5773                one, or vice versa.  */
5774             continue;
5775
5776           /* Ignore functions which haven't been explicitly
5777              declared.  */
5778           if (DECL_ANTICIPATED (fn))
5779             continue;
5780
5781           /* See if there's a match.  */
5782           fntype = TREE_TYPE (fn);
5783           if (is_ptrmem)
5784             fntype = build_ptrmemfunc_type (build_pointer_type (fntype));
5785           else if (!is_reference)
5786             fntype = build_pointer_type (fntype);
5787
5788           if (can_convert_arg (target_type, fntype, fn, LOOKUP_NORMAL))
5789             matches = tree_cons (fn, NULL_TREE, matches);
5790         }
5791     }
5792
5793   /* Now, if we've already got a match (or matches), there's no need
5794      to proceed to the template functions.  But, if we don't have a
5795      match we need to look at them, too.  */
5796   if (!matches)
5797     {
5798       tree target_fn_type;
5799       tree target_arg_types;
5800       tree target_ret_type;
5801       tree fns;
5802
5803       if (is_ptrmem)
5804         target_fn_type
5805           = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (target_type));
5806       else
5807         target_fn_type = TREE_TYPE (target_type);
5808       target_arg_types = TYPE_ARG_TYPES (target_fn_type);
5809       target_ret_type = TREE_TYPE (target_fn_type);
5810
5811       /* Never do unification on the 'this' parameter.  */
5812       if (TREE_CODE (target_fn_type) == METHOD_TYPE)
5813         target_arg_types = TREE_CHAIN (target_arg_types);
5814
5815       for (fns = overload; fns; fns = OVL_NEXT (fns))
5816         {
5817           tree fn = OVL_CURRENT (fns);
5818           tree instantiation;
5819           tree instantiation_type;
5820           tree targs;
5821
5822           if (TREE_CODE (fn) != TEMPLATE_DECL)
5823             /* We're only looking for templates.  */
5824             continue;
5825
5826           if ((TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
5827               != is_ptrmem)
5828             /* We're not looking for a non-static member, and this is
5829                one, or vice versa.  */
5830             continue;
5831
5832           /* Try to do argument deduction.  */
5833           targs = make_tree_vec (DECL_NTPARMS (fn));
5834           if (fn_type_unification (fn, explicit_targs, targs,
5835                                    target_arg_types, target_ret_type,
5836                                    DEDUCE_EXACT, LOOKUP_NORMAL))
5837             /* Argument deduction failed.  */
5838             continue;
5839
5840           /* Instantiate the template.  */
5841           instantiation = instantiate_template (fn, targs, flags);
5842           if (instantiation == error_mark_node)
5843             /* Instantiation failed.  */
5844             continue;
5845
5846           /* See if there's a match.  */
5847           instantiation_type = TREE_TYPE (instantiation);
5848           if (is_ptrmem)
5849             instantiation_type =
5850               build_ptrmemfunc_type (build_pointer_type (instantiation_type));
5851           else if (!is_reference)
5852             instantiation_type = build_pointer_type (instantiation_type);
5853           if (can_convert_arg (target_type, instantiation_type, instantiation,
5854                                LOOKUP_NORMAL))
5855             matches = tree_cons (instantiation, fn, matches);
5856         }
5857
5858       /* Now, remove all but the most specialized of the matches.  */
5859       if (matches)
5860         {
5861           tree match = most_specialized_instantiation (matches);
5862
5863           if (match != error_mark_node)
5864             matches = tree_cons (TREE_PURPOSE (match),
5865                                  NULL_TREE,
5866                                  NULL_TREE);
5867         }
5868     }
5869
5870   /* Now we should have exactly one function in MATCHES.  */
5871   if (matches == NULL_TREE)
5872     {
5873       /* There were *no* matches.  */
5874       if (flags & tf_error)
5875         {
5876           error ("no matches converting function %qD to type %q#T",
5877                  DECL_NAME (OVL_FUNCTION (overload)),
5878                  target_type);
5879
5880           /* print_candidates expects a chain with the functions in
5881              TREE_VALUE slots, so we cons one up here (we're losing anyway,
5882              so why be clever?).  */
5883           for (; overload; overload = OVL_NEXT (overload))
5884             matches = tree_cons (NULL_TREE, OVL_CURRENT (overload),
5885                                  matches);
5886
5887           print_candidates (matches);
5888         }
5889       return error_mark_node;
5890     }
5891   else if (TREE_CHAIN (matches))
5892     {
5893       /* There were too many matches.  */
5894
5895       if (flags & tf_error)
5896         {
5897           tree match;
5898
5899           error ("converting overloaded function %qD to type %q#T is ambiguous",
5900                     DECL_NAME (OVL_FUNCTION (overload)),
5901                     target_type);
5902
5903           /* Since print_candidates expects the functions in the
5904              TREE_VALUE slot, we flip them here.  */
5905           for (match = matches; match; match = TREE_CHAIN (match))
5906             TREE_VALUE (match) = TREE_PURPOSE (match);
5907
5908           print_candidates (matches);
5909         }
5910
5911       return error_mark_node;
5912     }
5913
5914   /* Good, exactly one match.  Now, convert it to the correct type.  */
5915   fn = TREE_PURPOSE (matches);
5916
5917   if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)
5918       && !(flags & tf_ptrmem_ok) && !flag_ms_extensions)
5919     {
5920       static int explained;
5921
5922       if (!(flags & tf_error))
5923         return error_mark_node;
5924
5925       pedwarn ("assuming pointer to member %qD", fn);
5926       if (!explained)
5927         {
5928           pedwarn ("(a pointer to member can only be formed with %<&%E%>)", fn);
5929           explained = 1;
5930         }
5931     }
5932
5933   /* If we're doing overload resolution purely for the purpose of
5934      determining conversion sequences, we should not consider the
5935      function used.  If this conversion sequence is selected, the
5936      function will be marked as used at this point.  */
5937   if (!(flags & tf_conv))
5938     mark_used (fn);
5939
5940   if (TYPE_PTRFN_P (target_type) || TYPE_PTRMEMFUNC_P (target_type))
5941     return build_unary_op (ADDR_EXPR, fn, 0);
5942   else
5943     {
5944       /* The target must be a REFERENCE_TYPE.  Above, build_unary_op
5945          will mark the function as addressed, but here we must do it
5946          explicitly.  */
5947       cxx_mark_addressable (fn);
5948
5949       return fn;
5950     }
5951 }
5952
5953 /* This function will instantiate the type of the expression given in
5954    RHS to match the type of LHSTYPE.  If errors exist, then return
5955    error_mark_node. FLAGS is a bit mask.  If TF_ERROR is set, then
5956    we complain on errors.  If we are not complaining, never modify rhs,
5957    as overload resolution wants to try many possible instantiations, in
5958    the hope that at least one will work.
5959
5960    For non-recursive calls, LHSTYPE should be a function, pointer to
5961    function, or a pointer to member function.  */
5962
5963 tree
5964 instantiate_type (tree lhstype, tree rhs, tsubst_flags_t flags)
5965 {
5966   tsubst_flags_t flags_in = flags;
5967
5968   flags &= ~tf_ptrmem_ok;
5969
5970   if (TREE_CODE (lhstype) == UNKNOWN_TYPE)
5971     {
5972       if (flags & tf_error)
5973         error ("not enough type information");
5974       return error_mark_node;
5975     }
5976
5977   if (TREE_TYPE (rhs) != NULL_TREE && ! (type_unknown_p (rhs)))
5978     {
5979       if (same_type_p (lhstype, TREE_TYPE (rhs)))
5980         return rhs;
5981       if (flag_ms_extensions
5982           && TYPE_PTRMEMFUNC_P (lhstype)
5983           && !TYPE_PTRMEMFUNC_P (TREE_TYPE (rhs)))
5984         /* Microsoft allows `A::f' to be resolved to a
5985            pointer-to-member.  */
5986         ;
5987       else
5988         {
5989           if (flags & tf_error)
5990             error ("argument of type %qT does not match %qT",
5991                    TREE_TYPE (rhs), lhstype);
5992           return error_mark_node;
5993         }
5994     }
5995
5996   if (TREE_CODE (rhs) == BASELINK)
5997     rhs = BASELINK_FUNCTIONS (rhs);
5998
5999   /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
6000      deduce any type information.  */
6001   if (TREE_CODE (rhs) == NON_DEPENDENT_EXPR)
6002     {
6003       if (flags & tf_error)
6004         error ("not enough type information");
6005       return error_mark_node;
6006     }
6007
6008   /* We don't overwrite rhs if it is an overloaded function.
6009      Copying it would destroy the tree link.  */
6010   if (TREE_CODE (rhs) != OVERLOAD)
6011     rhs = copy_node (rhs);
6012
6013   /* This should really only be used when attempting to distinguish
6014      what sort of a pointer to function we have.  For now, any
6015      arithmetic operation which is not supported on pointers
6016      is rejected as an error.  */
6017
6018   switch (TREE_CODE (rhs))
6019     {
6020     case TYPE_EXPR:
6021     case CONVERT_EXPR:
6022     case SAVE_EXPR:
6023     case CONSTRUCTOR:
6024       gcc_unreachable ();
6025
6026     case INDIRECT_REF:
6027     case ARRAY_REF:
6028       {
6029         tree new_rhs;
6030
6031         new_rhs = instantiate_type (build_pointer_type (lhstype),
6032                                     TREE_OPERAND (rhs, 0), flags);
6033         if (new_rhs == error_mark_node)
6034           return error_mark_node;
6035
6036         TREE_TYPE (rhs) = lhstype;
6037         TREE_OPERAND (rhs, 0) = new_rhs;
6038         return rhs;
6039       }
6040
6041     case NOP_EXPR:
6042       rhs = copy_node (TREE_OPERAND (rhs, 0));
6043       TREE_TYPE (rhs) = unknown_type_node;
6044       return instantiate_type (lhstype, rhs, flags);
6045
6046     case COMPONENT_REF:
6047       {
6048         tree member = TREE_OPERAND (rhs, 1);
6049
6050         member = instantiate_type (lhstype, member, flags);
6051         if (member != error_mark_node
6052             && TREE_SIDE_EFFECTS (TREE_OPERAND (rhs, 0)))
6053           /* Do not lose object's side effects.  */
6054           return build2 (COMPOUND_EXPR, TREE_TYPE (member),
6055                          TREE_OPERAND (rhs, 0), member);
6056         return member;
6057       }
6058
6059     case OFFSET_REF:
6060       rhs = TREE_OPERAND (rhs, 1);
6061       if (BASELINK_P (rhs))
6062         return instantiate_type (lhstype, BASELINK_FUNCTIONS (rhs), flags_in);
6063
6064       /* This can happen if we are forming a pointer-to-member for a
6065          member template.  */
6066       gcc_assert (TREE_CODE (rhs) == TEMPLATE_ID_EXPR);
6067
6068       /* Fall through.  */
6069
6070     case TEMPLATE_ID_EXPR:
6071       {
6072         tree fns = TREE_OPERAND (rhs, 0);
6073         tree args = TREE_OPERAND (rhs, 1);
6074
6075         return
6076           resolve_address_of_overloaded_function (lhstype, fns, flags_in,
6077                                                   /*template_only=*/true,
6078                                                   args);
6079       }
6080
6081     case OVERLOAD:
6082     case FUNCTION_DECL:
6083       return
6084         resolve_address_of_overloaded_function (lhstype, rhs, flags_in,
6085                                                 /*template_only=*/false,
6086                                                 /*explicit_targs=*/NULL_TREE);
6087
6088     case CALL_EXPR:
6089       /* This is too hard for now.  */
6090       gcc_unreachable ();
6091
6092     case PLUS_EXPR:
6093     case MINUS_EXPR:
6094     case COMPOUND_EXPR:
6095       TREE_OPERAND (rhs, 0)
6096         = instantiate_type (lhstype, TREE_OPERAND (rhs, 0), flags);
6097       if (TREE_OPERAND (rhs, 0) == error_mark_node)
6098         return error_mark_node;
6099       TREE_OPERAND (rhs, 1)
6100         = instantiate_type (lhstype, TREE_OPERAND (rhs, 1), flags);
6101       if (TREE_OPERAND (rhs, 1) == error_mark_node)
6102         return error_mark_node;
6103
6104       TREE_TYPE (rhs) = lhstype;
6105       return rhs;
6106
6107     case MULT_EXPR:
6108     case TRUNC_DIV_EXPR:
6109     case FLOOR_DIV_EXPR:
6110     case CEIL_DIV_EXPR:
6111     case ROUND_DIV_EXPR:
6112     case RDIV_EXPR:
6113     case TRUNC_MOD_EXPR:
6114     case FLOOR_MOD_EXPR:
6115     case CEIL_MOD_EXPR:
6116     case ROUND_MOD_EXPR:
6117     case FIX_ROUND_EXPR:
6118     case FIX_FLOOR_EXPR:
6119     case FIX_CEIL_EXPR:
6120     case FIX_TRUNC_EXPR:
6121     case FLOAT_EXPR:
6122     case NEGATE_EXPR:
6123     case ABS_EXPR:
6124     case MAX_EXPR:
6125     case MIN_EXPR:
6126
6127     case BIT_AND_EXPR:
6128     case BIT_IOR_EXPR:
6129     case BIT_XOR_EXPR:
6130     case LSHIFT_EXPR:
6131     case RSHIFT_EXPR:
6132     case LROTATE_EXPR:
6133     case RROTATE_EXPR:
6134
6135     case PREINCREMENT_EXPR:
6136     case PREDECREMENT_EXPR:
6137     case POSTINCREMENT_EXPR:
6138     case POSTDECREMENT_EXPR:
6139       if (flags & tf_error)
6140         error ("invalid operation on uninstantiated type");
6141       return error_mark_node;
6142
6143     case TRUTH_AND_EXPR:
6144     case TRUTH_OR_EXPR:
6145     case TRUTH_XOR_EXPR:
6146     case LT_EXPR:
6147     case LE_EXPR:
6148     case GT_EXPR:
6149     case GE_EXPR:
6150     case EQ_EXPR:
6151     case NE_EXPR:
6152     case TRUTH_ANDIF_EXPR:
6153     case TRUTH_ORIF_EXPR:
6154     case TRUTH_NOT_EXPR:
6155       if (flags & tf_error)
6156         error ("not enough type information");
6157       return error_mark_node;
6158
6159     case COND_EXPR:
6160       if (type_unknown_p (TREE_OPERAND (rhs, 0)))
6161         {
6162           if (flags & tf_error)
6163             error ("not enough type information");
6164           return error_mark_node;
6165         }
6166       TREE_OPERAND (rhs, 1)
6167         = instantiate_type (lhstype, TREE_OPERAND (rhs, 1), flags);
6168       if (TREE_OPERAND (rhs, 1) == error_mark_node)
6169         return error_mark_node;
6170       TREE_OPERAND (rhs, 2)
6171         = instantiate_type (lhstype, TREE_OPERAND (rhs, 2), flags);
6172       if (TREE_OPERAND (rhs, 2) == error_mark_node)
6173         return error_mark_node;
6174
6175       TREE_TYPE (rhs) = lhstype;
6176       return rhs;
6177
6178     case MODIFY_EXPR:
6179       TREE_OPERAND (rhs, 1)
6180         = instantiate_type (lhstype, TREE_OPERAND (rhs, 1), flags);
6181       if (TREE_OPERAND (rhs, 1) == error_mark_node)
6182         return error_mark_node;
6183
6184       TREE_TYPE (rhs) = lhstype;
6185       return rhs;
6186
6187     case ADDR_EXPR:
6188     {
6189       if (PTRMEM_OK_P (rhs))
6190         flags |= tf_ptrmem_ok;
6191
6192       return instantiate_type (lhstype, TREE_OPERAND (rhs, 0), flags);
6193     }
6194
6195     case ERROR_MARK:
6196       return error_mark_node;
6197
6198     default:
6199       gcc_unreachable ();
6200     }
6201   return error_mark_node;
6202 }
6203 \f
6204 /* Return the name of the virtual function pointer field
6205    (as an IDENTIFIER_NODE) for the given TYPE.  Note that
6206    this may have to look back through base types to find the
6207    ultimate field name.  (For single inheritance, these could
6208    all be the same name.  Who knows for multiple inheritance).  */
6209
6210 static tree
6211 get_vfield_name (tree type)
6212 {
6213   tree binfo, base_binfo;
6214   char *buf;
6215
6216   for (binfo = TYPE_BINFO (type);
6217        BINFO_N_BASE_BINFOS (binfo);
6218        binfo = base_binfo)
6219     {
6220       base_binfo = BINFO_BASE_BINFO (binfo, 0);
6221
6222       if (BINFO_VIRTUAL_P (base_binfo)
6223           || !TYPE_CONTAINS_VPTR_P (BINFO_TYPE (base_binfo)))
6224         break;
6225     }
6226
6227   type = BINFO_TYPE (binfo);
6228   buf = (char *) alloca (sizeof (VFIELD_NAME_FORMAT)
6229                          + TYPE_NAME_LENGTH (type) + 2);
6230   sprintf (buf, VFIELD_NAME_FORMAT,
6231            IDENTIFIER_POINTER (constructor_name (type)));
6232   return get_identifier (buf);
6233 }
6234
6235 void
6236 print_class_statistics (void)
6237 {
6238 #ifdef GATHER_STATISTICS
6239   fprintf (stderr, "convert_harshness = %d\n", n_convert_harshness);
6240   fprintf (stderr, "compute_conversion_costs = %d\n", n_compute_conversion_costs);
6241   if (n_vtables)
6242     {
6243       fprintf (stderr, "vtables = %d; vtable searches = %d\n",
6244                n_vtables, n_vtable_searches);
6245       fprintf (stderr, "vtable entries = %d; vtable elems = %d\n",
6246                n_vtable_entries, n_vtable_elems);
6247     }
6248 #endif
6249 }
6250
6251 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
6252    according to [class]:
6253                                           The class-name is also inserted
6254    into  the scope of the class itself.  For purposes of access checking,
6255    the inserted class name is treated as if it were a public member name.  */
6256
6257 void
6258 build_self_reference (void)
6259 {
6260   tree name = constructor_name (current_class_type);
6261   tree value = build_lang_decl (TYPE_DECL, name, current_class_type);
6262   tree saved_cas;
6263
6264   DECL_NONLOCAL (value) = 1;
6265   DECL_CONTEXT (value) = current_class_type;
6266   DECL_ARTIFICIAL (value) = 1;
6267   SET_DECL_SELF_REFERENCE_P (value);
6268
6269   if (processing_template_decl)
6270     value = push_template_decl (value);
6271
6272   saved_cas = current_access_specifier;
6273   current_access_specifier = access_public_node;
6274   finish_member_declaration (value);
6275   current_access_specifier = saved_cas;
6276 }
6277
6278 /* Returns 1 if TYPE contains only padding bytes.  */
6279
6280 int
6281 is_empty_class (tree type)
6282 {
6283   if (type == error_mark_node)
6284     return 0;
6285
6286   if (! IS_AGGR_TYPE (type))
6287     return 0;
6288
6289   /* In G++ 3.2, whether or not a class was empty was determined by
6290      looking at its size.  */
6291   if (abi_version_at_least (2))
6292     return CLASSTYPE_EMPTY_P (type);
6293   else
6294     return integer_zerop (CLASSTYPE_SIZE (type));
6295 }
6296
6297 /* Returns true if TYPE contains an empty class.  */
6298
6299 static bool
6300 contains_empty_class_p (tree type)
6301 {
6302   if (is_empty_class (type))
6303     return true;
6304   if (CLASS_TYPE_P (type))
6305     {
6306       tree field;
6307       tree binfo;
6308       tree base_binfo;
6309       int i;
6310
6311       for (binfo = TYPE_BINFO (type), i = 0;
6312            BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
6313         if (contains_empty_class_p (BINFO_TYPE (base_binfo)))
6314           return true;
6315       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
6316         if (TREE_CODE (field) == FIELD_DECL
6317             && !DECL_ARTIFICIAL (field)
6318             && is_empty_class (TREE_TYPE (field)))
6319           return true;
6320     }
6321   else if (TREE_CODE (type) == ARRAY_TYPE)
6322     return contains_empty_class_p (TREE_TYPE (type));
6323   return false;
6324 }
6325
6326 /* Note that NAME was looked up while the current class was being
6327    defined and that the result of that lookup was DECL.  */
6328
6329 void
6330 maybe_note_name_used_in_class (tree name, tree decl)
6331 {
6332   splay_tree names_used;
6333
6334   /* If we're not defining a class, there's nothing to do.  */
6335   if (!(innermost_scope_kind() == sk_class
6336         && TYPE_BEING_DEFINED (current_class_type)))
6337     return;
6338
6339   /* If there's already a binding for this NAME, then we don't have
6340      anything to worry about.  */
6341   if (lookup_member (current_class_type, name,
6342                      /*protect=*/0, /*want_type=*/false))
6343     return;
6344
6345   if (!current_class_stack[current_class_depth - 1].names_used)
6346     current_class_stack[current_class_depth - 1].names_used
6347       = splay_tree_new (splay_tree_compare_pointers, 0, 0);
6348   names_used = current_class_stack[current_class_depth - 1].names_used;
6349
6350   splay_tree_insert (names_used,
6351                      (splay_tree_key) name,
6352                      (splay_tree_value) decl);
6353 }
6354
6355 /* Note that NAME was declared (as DECL) in the current class.  Check
6356    to see that the declaration is valid.  */
6357
6358 void
6359 note_name_declared_in_class (tree name, tree decl)
6360 {
6361   splay_tree names_used;
6362   splay_tree_node n;
6363
6364   /* Look to see if we ever used this name.  */
6365   names_used
6366     = current_class_stack[current_class_depth - 1].names_used;
6367   if (!names_used)
6368     return;
6369
6370   n = splay_tree_lookup (names_used, (splay_tree_key) name);
6371   if (n)
6372     {
6373       /* [basic.scope.class]
6374
6375          A name N used in a class S shall refer to the same declaration
6376          in its context and when re-evaluated in the completed scope of
6377          S.  */
6378       error ("declaration of %q#D", decl);
6379       error ("changes meaning of %qD from %q+#D",
6380              DECL_NAME (OVL_CURRENT (decl)), (tree) n->value);
6381     }
6382 }
6383
6384 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
6385    Secondary vtables are merged with primary vtables; this function
6386    will return the VAR_DECL for the primary vtable.  */
6387
6388 tree
6389 get_vtbl_decl_for_binfo (tree binfo)
6390 {
6391   tree decl;
6392
6393   decl = BINFO_VTABLE (binfo);
6394   if (decl && TREE_CODE (decl) == PLUS_EXPR)
6395     {
6396       gcc_assert (TREE_CODE (TREE_OPERAND (decl, 0)) == ADDR_EXPR);
6397       decl = TREE_OPERAND (TREE_OPERAND (decl, 0), 0);
6398     }
6399   if (decl)
6400     gcc_assert (TREE_CODE (decl) == VAR_DECL);
6401   return decl;
6402 }
6403
6404
6405 /* Returns the binfo for the primary base of BINFO.  If the resulting
6406    BINFO is a virtual base, and it is inherited elsewhere in the
6407    hierarchy, then the returned binfo might not be the primary base of
6408    BINFO in the complete object.  Check BINFO_PRIMARY_P or
6409    BINFO_LOST_PRIMARY_P to be sure.  */
6410
6411 static tree
6412 get_primary_binfo (tree binfo)
6413 {
6414   tree primary_base;
6415
6416   primary_base = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (binfo));
6417   if (!primary_base)
6418     return NULL_TREE;
6419
6420   return copied_binfo (primary_base, binfo);
6421 }
6422
6423 /* If INDENTED_P is zero, indent to INDENT. Return nonzero.  */
6424
6425 static int
6426 maybe_indent_hierarchy (FILE * stream, int indent, int indented_p)
6427 {
6428   if (!indented_p)
6429     fprintf (stream, "%*s", indent, "");
6430   return 1;
6431 }
6432
6433 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
6434    INDENT should be zero when called from the top level; it is
6435    incremented recursively.  IGO indicates the next expected BINFO in
6436    inheritance graph ordering.  */
6437
6438 static tree
6439 dump_class_hierarchy_r (FILE *stream,
6440                         int flags,
6441                         tree binfo,
6442                         tree igo,
6443                         int indent)
6444 {
6445   int indented = 0;
6446   tree base_binfo;
6447   int i;
6448
6449   indented = maybe_indent_hierarchy (stream, indent, 0);
6450   fprintf (stream, "%s (0x%lx) ",
6451            type_as_string (BINFO_TYPE (binfo), TFF_PLAIN_IDENTIFIER),
6452            (unsigned long) binfo);
6453   if (binfo != igo)
6454     {
6455       fprintf (stream, "alternative-path\n");
6456       return igo;
6457     }
6458   igo = TREE_CHAIN (binfo);
6459
6460   fprintf (stream, HOST_WIDE_INT_PRINT_DEC,
6461            tree_low_cst (BINFO_OFFSET (binfo), 0));
6462   if (is_empty_class (BINFO_TYPE (binfo)))
6463     fprintf (stream, " empty");
6464   else if (CLASSTYPE_NEARLY_EMPTY_P (BINFO_TYPE (binfo)))
6465     fprintf (stream, " nearly-empty");
6466   if (BINFO_VIRTUAL_P (binfo))
6467     fprintf (stream, " virtual");
6468   fprintf (stream, "\n");
6469
6470   indented = 0;
6471   if (BINFO_PRIMARY_P (binfo))
6472     {
6473       indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6474       fprintf (stream, " primary-for %s (0x%lx)",
6475                type_as_string (BINFO_TYPE (BINFO_INHERITANCE_CHAIN (binfo)),
6476                                TFF_PLAIN_IDENTIFIER),
6477                (unsigned long)BINFO_INHERITANCE_CHAIN (binfo));
6478     }
6479   if (BINFO_LOST_PRIMARY_P (binfo))
6480     {
6481       indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6482       fprintf (stream, " lost-primary");
6483     }
6484   if (indented)
6485     fprintf (stream, "\n");
6486
6487   if (!(flags & TDF_SLIM))
6488     {
6489       int indented = 0;
6490
6491       if (BINFO_SUBVTT_INDEX (binfo))
6492         {
6493           indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6494           fprintf (stream, " subvttidx=%s",
6495                    expr_as_string (BINFO_SUBVTT_INDEX (binfo),
6496                                    TFF_PLAIN_IDENTIFIER));
6497         }
6498       if (BINFO_VPTR_INDEX (binfo))
6499         {
6500           indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6501           fprintf (stream, " vptridx=%s",
6502                    expr_as_string (BINFO_VPTR_INDEX (binfo),
6503                                    TFF_PLAIN_IDENTIFIER));
6504         }
6505       if (BINFO_VPTR_FIELD (binfo))
6506         {
6507           indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6508           fprintf (stream, " vbaseoffset=%s",
6509                    expr_as_string (BINFO_VPTR_FIELD (binfo),
6510                                    TFF_PLAIN_IDENTIFIER));
6511         }
6512       if (BINFO_VTABLE (binfo))
6513         {
6514           indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6515           fprintf (stream, " vptr=%s",
6516                    expr_as_string (BINFO_VTABLE (binfo),
6517                                    TFF_PLAIN_IDENTIFIER));
6518         }
6519
6520       if (indented)
6521         fprintf (stream, "\n");
6522     }
6523
6524   for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
6525     igo = dump_class_hierarchy_r (stream, flags, base_binfo, igo, indent + 2);
6526
6527   return igo;
6528 }
6529
6530 /* Dump the BINFO hierarchy for T.  */
6531
6532 static void
6533 dump_class_hierarchy_1 (FILE *stream, int flags, tree t)
6534 {
6535   fprintf (stream, "Class %s\n", type_as_string (t, TFF_PLAIN_IDENTIFIER));
6536   fprintf (stream, "   size=%lu align=%lu\n",
6537            (unsigned long)(tree_low_cst (TYPE_SIZE (t), 0) / BITS_PER_UNIT),
6538            (unsigned long)(TYPE_ALIGN (t) / BITS_PER_UNIT));
6539   fprintf (stream, "   base size=%lu base align=%lu\n",
6540            (unsigned long)(tree_low_cst (TYPE_SIZE (CLASSTYPE_AS_BASE (t)), 0)
6541                            / BITS_PER_UNIT),
6542            (unsigned long)(TYPE_ALIGN (CLASSTYPE_AS_BASE (t))
6543                            / BITS_PER_UNIT));
6544   dump_class_hierarchy_r (stream, flags, TYPE_BINFO (t), TYPE_BINFO (t), 0);
6545   fprintf (stream, "\n");
6546 }
6547
6548 /* Debug interface to hierarchy dumping.  */
6549
6550 void
6551 debug_class (tree t)
6552 {
6553   dump_class_hierarchy_1 (stderr, TDF_SLIM, t);
6554 }
6555
6556 static void
6557 dump_class_hierarchy (tree t)
6558 {
6559   int flags;
6560   FILE *stream = dump_begin (TDI_class, &flags);
6561
6562   if (stream)
6563     {
6564       dump_class_hierarchy_1 (stream, flags, t);
6565       dump_end (TDI_class, stream);
6566     }
6567 }
6568
6569 static void
6570 dump_array (FILE * stream, tree decl)
6571 {
6572   tree value;
6573   unsigned HOST_WIDE_INT ix;
6574   HOST_WIDE_INT elt;
6575   tree size = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (decl)));
6576
6577   elt = (tree_low_cst (TYPE_SIZE (TREE_TYPE (TREE_TYPE (decl))), 0)
6578          / BITS_PER_UNIT);
6579   fprintf (stream, "%s:", decl_as_string (decl, TFF_PLAIN_IDENTIFIER));
6580   fprintf (stream, " %s entries",
6581            expr_as_string (size_binop (PLUS_EXPR, size, size_one_node),
6582                            TFF_PLAIN_IDENTIFIER));
6583   fprintf (stream, "\n");
6584
6585   FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (DECL_INITIAL (decl)),
6586                               ix, value)
6587     fprintf (stream, "%-4ld  %s\n", (long)(ix * elt),
6588              expr_as_string (value, TFF_PLAIN_IDENTIFIER));
6589 }
6590
6591 static void
6592 dump_vtable (tree t, tree binfo, tree vtable)
6593 {
6594   int flags;
6595   FILE *stream = dump_begin (TDI_class, &flags);
6596
6597   if (!stream)
6598     return;
6599
6600   if (!(flags & TDF_SLIM))
6601     {
6602       int ctor_vtbl_p = TYPE_BINFO (t) != binfo;
6603
6604       fprintf (stream, "%s for %s",
6605                ctor_vtbl_p ? "Construction vtable" : "Vtable",
6606                type_as_string (BINFO_TYPE (binfo), TFF_PLAIN_IDENTIFIER));
6607       if (ctor_vtbl_p)
6608         {
6609           if (!BINFO_VIRTUAL_P (binfo))
6610             fprintf (stream, " (0x%lx instance)", (unsigned long)binfo);
6611           fprintf (stream, " in %s", type_as_string (t, TFF_PLAIN_IDENTIFIER));
6612         }
6613       fprintf (stream, "\n");
6614       dump_array (stream, vtable);
6615       fprintf (stream, "\n");
6616     }
6617
6618   dump_end (TDI_class, stream);
6619 }
6620
6621 static void
6622 dump_vtt (tree t, tree vtt)
6623 {
6624   int flags;
6625   FILE *stream = dump_begin (TDI_class, &flags);
6626
6627   if (!stream)
6628     return;
6629
6630   if (!(flags & TDF_SLIM))
6631     {
6632       fprintf (stream, "VTT for %s\n",
6633                type_as_string (t, TFF_PLAIN_IDENTIFIER));
6634       dump_array (stream, vtt);
6635       fprintf (stream, "\n");
6636     }
6637
6638   dump_end (TDI_class, stream);
6639 }
6640
6641 /* Dump a function or thunk and its thunkees.  */
6642
6643 static void
6644 dump_thunk (FILE *stream, int indent, tree thunk)
6645 {
6646   static const char spaces[] = "        ";
6647   tree name = DECL_NAME (thunk);
6648   tree thunks;
6649
6650   fprintf (stream, "%.*s%p %s %s", indent, spaces,
6651            (void *)thunk,
6652            !DECL_THUNK_P (thunk) ? "function"
6653            : DECL_THIS_THUNK_P (thunk) ? "this-thunk" : "covariant-thunk",
6654            name ? IDENTIFIER_POINTER (name) : "<unset>");
6655   if (DECL_THUNK_P (thunk))
6656     {
6657       HOST_WIDE_INT fixed_adjust = THUNK_FIXED_OFFSET (thunk);
6658       tree virtual_adjust = THUNK_VIRTUAL_OFFSET (thunk);
6659
6660       fprintf (stream, " fixed=" HOST_WIDE_INT_PRINT_DEC, fixed_adjust);
6661       if (!virtual_adjust)
6662         /*NOP*/;
6663       else if (DECL_THIS_THUNK_P (thunk))
6664         fprintf (stream, " vcall="  HOST_WIDE_INT_PRINT_DEC,
6665                  tree_low_cst (virtual_adjust, 0));
6666       else
6667         fprintf (stream, " vbase=" HOST_WIDE_INT_PRINT_DEC "(%s)",
6668                  tree_low_cst (BINFO_VPTR_FIELD (virtual_adjust), 0),
6669                  type_as_string (BINFO_TYPE (virtual_adjust), TFF_SCOPE));
6670       if (THUNK_ALIAS (thunk))
6671         fprintf (stream, " alias to %p", (void *)THUNK_ALIAS (thunk));
6672     }
6673   fprintf (stream, "\n");
6674   for (thunks = DECL_THUNKS (thunk); thunks; thunks = TREE_CHAIN (thunks))
6675     dump_thunk (stream, indent + 2, thunks);
6676 }
6677
6678 /* Dump the thunks for FN.  */
6679
6680 void
6681 debug_thunks (tree fn)
6682 {
6683   dump_thunk (stderr, 0, fn);
6684 }
6685
6686 /* Virtual function table initialization.  */
6687
6688 /* Create all the necessary vtables for T and its base classes.  */
6689
6690 static void
6691 finish_vtbls (tree t)
6692 {
6693   tree list;
6694   tree vbase;
6695
6696   /* We lay out the primary and secondary vtables in one contiguous
6697      vtable.  The primary vtable is first, followed by the non-virtual
6698      secondary vtables in inheritance graph order.  */
6699   list = build_tree_list (BINFO_VTABLE (TYPE_BINFO (t)), NULL_TREE);
6700   accumulate_vtbl_inits (TYPE_BINFO (t), TYPE_BINFO (t),
6701                          TYPE_BINFO (t), t, list);
6702
6703   /* Then come the virtual bases, also in inheritance graph order.  */
6704   for (vbase = TYPE_BINFO (t); vbase; vbase = TREE_CHAIN (vbase))
6705     {
6706       if (!BINFO_VIRTUAL_P (vbase))
6707         continue;
6708       accumulate_vtbl_inits (vbase, vbase, TYPE_BINFO (t), t, list);
6709     }
6710
6711   if (BINFO_VTABLE (TYPE_BINFO (t)))
6712     initialize_vtable (TYPE_BINFO (t), TREE_VALUE (list));
6713 }
6714
6715 /* Initialize the vtable for BINFO with the INITS.  */
6716
6717 static void
6718 initialize_vtable (tree binfo, tree inits)
6719 {
6720   tree decl;
6721
6722   layout_vtable_decl (binfo, list_length (inits));
6723   decl = get_vtbl_decl_for_binfo (binfo);
6724   initialize_artificial_var (decl, inits);
6725   dump_vtable (BINFO_TYPE (binfo), binfo, decl);
6726 }
6727
6728 /* Build the VTT (virtual table table) for T.
6729    A class requires a VTT if it has virtual bases.
6730
6731    This holds
6732    1 - primary virtual pointer for complete object T
6733    2 - secondary VTTs for each direct non-virtual base of T which requires a
6734        VTT
6735    3 - secondary virtual pointers for each direct or indirect base of T which
6736        has virtual bases or is reachable via a virtual path from T.
6737    4 - secondary VTTs for each direct or indirect virtual base of T.
6738
6739    Secondary VTTs look like complete object VTTs without part 4.  */
6740
6741 static void
6742 build_vtt (tree t)
6743 {
6744   tree inits;
6745   tree type;
6746   tree vtt;
6747   tree index;
6748
6749   /* Build up the initializers for the VTT.  */
6750   inits = NULL_TREE;
6751   index = size_zero_node;
6752   build_vtt_inits (TYPE_BINFO (t), t, &inits, &index);
6753
6754   /* If we didn't need a VTT, we're done.  */
6755   if (!inits)
6756     return;
6757
6758   /* Figure out the type of the VTT.  */
6759   type = build_index_type (size_int (list_length (inits) - 1));
6760   type = build_cplus_array_type (const_ptr_type_node, type);
6761
6762   /* Now, build the VTT object itself.  */
6763   vtt = build_vtable (t, mangle_vtt_for_type (t), type);
6764   initialize_artificial_var (vtt, inits);
6765   /* Add the VTT to the vtables list.  */
6766   TREE_CHAIN (vtt) = TREE_CHAIN (CLASSTYPE_VTABLES (t));
6767   TREE_CHAIN (CLASSTYPE_VTABLES (t)) = vtt;
6768
6769   dump_vtt (t, vtt);
6770 }
6771
6772 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
6773    PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
6774    and CHAIN the vtable pointer for this binfo after construction is
6775    complete.  VALUE can also be another BINFO, in which case we recurse.  */
6776
6777 static tree
6778 binfo_ctor_vtable (tree binfo)
6779 {
6780   tree vt;
6781
6782   while (1)
6783     {
6784       vt = BINFO_VTABLE (binfo);
6785       if (TREE_CODE (vt) == TREE_LIST)
6786         vt = TREE_VALUE (vt);
6787       if (TREE_CODE (vt) == TREE_BINFO)
6788         binfo = vt;
6789       else
6790         break;
6791     }
6792
6793   return vt;
6794 }
6795
6796 /* Data for secondary VTT initialization.  */
6797 typedef struct secondary_vptr_vtt_init_data_s
6798 {
6799   /* Is this the primary VTT? */
6800   bool top_level_p;
6801
6802   /* Current index into the VTT.  */
6803   tree index;
6804
6805   /* TREE_LIST of initializers built up.  */
6806   tree inits;
6807
6808   /* The type being constructed by this secondary VTT.  */
6809   tree type_being_constructed;
6810 } secondary_vptr_vtt_init_data;
6811
6812 /* Recursively build the VTT-initializer for BINFO (which is in the
6813    hierarchy dominated by T).  INITS points to the end of the initializer
6814    list to date.  INDEX is the VTT index where the next element will be
6815    replaced.  Iff BINFO is the binfo for T, this is the top level VTT (i.e.
6816    not a subvtt for some base of T).  When that is so, we emit the sub-VTTs
6817    for virtual bases of T. When it is not so, we build the constructor
6818    vtables for the BINFO-in-T variant.  */
6819
6820 static tree *
6821 build_vtt_inits (tree binfo, tree t, tree *inits, tree *index)
6822 {
6823   int i;
6824   tree b;
6825   tree init;
6826   tree secondary_vptrs;
6827   secondary_vptr_vtt_init_data data;
6828   int top_level_p = SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t);
6829
6830   /* We only need VTTs for subobjects with virtual bases.  */
6831   if (!CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo)))
6832     return inits;
6833
6834   /* We need to use a construction vtable if this is not the primary
6835      VTT.  */
6836   if (!top_level_p)
6837     {
6838       build_ctor_vtbl_group (binfo, t);
6839
6840       /* Record the offset in the VTT where this sub-VTT can be found.  */
6841       BINFO_SUBVTT_INDEX (binfo) = *index;
6842     }
6843
6844   /* Add the address of the primary vtable for the complete object.  */
6845   init = binfo_ctor_vtable (binfo);
6846   *inits = build_tree_list (NULL_TREE, init);
6847   inits = &TREE_CHAIN (*inits);
6848   if (top_level_p)
6849     {
6850       gcc_assert (!BINFO_VPTR_INDEX (binfo));
6851       BINFO_VPTR_INDEX (binfo) = *index;
6852     }
6853   *index = size_binop (PLUS_EXPR, *index, TYPE_SIZE_UNIT (ptr_type_node));
6854
6855   /* Recursively add the secondary VTTs for non-virtual bases.  */
6856   for (i = 0; BINFO_BASE_ITERATE (binfo, i, b); ++i)
6857     if (!BINFO_VIRTUAL_P (b))
6858       inits = build_vtt_inits (b, t, inits, index);
6859
6860   /* Add secondary virtual pointers for all subobjects of BINFO with
6861      either virtual bases or reachable along a virtual path, except
6862      subobjects that are non-virtual primary bases.  */
6863   data.top_level_p = top_level_p;
6864   data.index = *index;
6865   data.inits = NULL;
6866   data.type_being_constructed = BINFO_TYPE (binfo);
6867
6868   dfs_walk_once (binfo, dfs_build_secondary_vptr_vtt_inits, NULL, &data);
6869
6870   *index = data.index;
6871
6872   /* The secondary vptrs come back in reverse order.  After we reverse
6873      them, and add the INITS, the last init will be the first element
6874      of the chain.  */
6875   secondary_vptrs = data.inits;
6876   if (secondary_vptrs)
6877     {
6878       *inits = nreverse (secondary_vptrs);
6879       inits = &TREE_CHAIN (secondary_vptrs);
6880       gcc_assert (*inits == NULL_TREE);
6881     }
6882
6883   if (top_level_p)
6884     /* Add the secondary VTTs for virtual bases in inheritance graph
6885        order.  */
6886     for (b = TYPE_BINFO (BINFO_TYPE (binfo)); b; b = TREE_CHAIN (b))
6887       {
6888         if (!BINFO_VIRTUAL_P (b))
6889           continue;
6890
6891         inits = build_vtt_inits (b, t, inits, index);
6892       }
6893   else
6894     /* Remove the ctor vtables we created.  */
6895     dfs_walk_all (binfo, dfs_fixup_binfo_vtbls, NULL, binfo);
6896
6897   return inits;
6898 }
6899
6900 /* Called from build_vtt_inits via dfs_walk.  BINFO is the binfo for the base
6901    in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure.  */
6902
6903 static tree
6904 dfs_build_secondary_vptr_vtt_inits (tree binfo, void *data_)
6905 {
6906   secondary_vptr_vtt_init_data *data = (secondary_vptr_vtt_init_data *)data_;
6907
6908   /* We don't care about bases that don't have vtables.  */
6909   if (!TYPE_VFIELD (BINFO_TYPE (binfo)))
6910     return dfs_skip_bases;
6911
6912   /* We're only interested in proper subobjects of the type being
6913      constructed.  */
6914   if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), data->type_being_constructed))
6915     return NULL_TREE;
6916
6917   /* We're only interested in bases with virtual bases or reachable
6918      via a virtual path from the type being constructed.  */
6919   if (!(CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo))
6920         || binfo_via_virtual (binfo, data->type_being_constructed)))
6921     return dfs_skip_bases;
6922
6923   /* We're not interested in non-virtual primary bases.  */
6924   if (!BINFO_VIRTUAL_P (binfo) && BINFO_PRIMARY_P (binfo))
6925     return NULL_TREE;
6926
6927   /* Record the index where this secondary vptr can be found.  */
6928   if (data->top_level_p)
6929     {
6930       gcc_assert (!BINFO_VPTR_INDEX (binfo));
6931       BINFO_VPTR_INDEX (binfo) = data->index;
6932
6933       if (BINFO_VIRTUAL_P (binfo))
6934         {
6935           /* It's a primary virtual base, and this is not a
6936              construction vtable.  Find the base this is primary of in
6937              the inheritance graph, and use that base's vtable
6938              now.  */
6939           while (BINFO_PRIMARY_P (binfo))
6940             binfo = BINFO_INHERITANCE_CHAIN (binfo);
6941         }
6942     }
6943
6944   /* Add the initializer for the secondary vptr itself.  */
6945   data->inits = tree_cons (NULL_TREE, binfo_ctor_vtable (binfo), data->inits);
6946
6947   /* Advance the vtt index.  */
6948   data->index = size_binop (PLUS_EXPR, data->index,
6949                             TYPE_SIZE_UNIT (ptr_type_node));
6950
6951   return NULL_TREE;
6952 }
6953
6954 /* Called from build_vtt_inits via dfs_walk. After building
6955    constructor vtables and generating the sub-vtt from them, we need
6956    to restore the BINFO_VTABLES that were scribbled on.  DATA is the
6957    binfo of the base whose sub vtt was generated.  */
6958
6959 static tree
6960 dfs_fixup_binfo_vtbls (tree binfo, void* data)
6961 {
6962   tree vtable = BINFO_VTABLE (binfo);
6963
6964   if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
6965     /* If this class has no vtable, none of its bases do.  */
6966     return dfs_skip_bases;
6967
6968   if (!vtable)
6969     /* This might be a primary base, so have no vtable in this
6970        hierarchy.  */
6971     return NULL_TREE;
6972
6973   /* If we scribbled the construction vtable vptr into BINFO, clear it
6974      out now.  */
6975   if (TREE_CODE (vtable) == TREE_LIST
6976       && (TREE_PURPOSE (vtable) == (tree) data))
6977     BINFO_VTABLE (binfo) = TREE_CHAIN (vtable);
6978
6979   return NULL_TREE;
6980 }
6981
6982 /* Build the construction vtable group for BINFO which is in the
6983    hierarchy dominated by T.  */
6984
6985 static void
6986 build_ctor_vtbl_group (tree binfo, tree t)
6987 {
6988   tree list;
6989   tree type;
6990   tree vtbl;
6991   tree inits;
6992   tree id;
6993   tree vbase;
6994
6995   /* See if we've already created this construction vtable group.  */
6996   id = mangle_ctor_vtbl_for_type (t, binfo);
6997   if (IDENTIFIER_GLOBAL_VALUE (id))
6998     return;
6999
7000   gcc_assert (!SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t));
7001   /* Build a version of VTBL (with the wrong type) for use in
7002      constructing the addresses of secondary vtables in the
7003      construction vtable group.  */
7004   vtbl = build_vtable (t, id, ptr_type_node);
7005   DECL_CONSTRUCTION_VTABLE_P (vtbl) = 1;
7006   list = build_tree_list (vtbl, NULL_TREE);
7007   accumulate_vtbl_inits (binfo, TYPE_BINFO (TREE_TYPE (binfo)),
7008                          binfo, t, list);
7009
7010   /* Add the vtables for each of our virtual bases using the vbase in T
7011      binfo.  */
7012   for (vbase = TYPE_BINFO (BINFO_TYPE (binfo));
7013        vbase;
7014        vbase = TREE_CHAIN (vbase))
7015     {
7016       tree b;
7017
7018       if (!BINFO_VIRTUAL_P (vbase))
7019         continue;
7020       b = copied_binfo (vbase, binfo);
7021
7022       accumulate_vtbl_inits (b, vbase, binfo, t, list);
7023     }
7024   inits = TREE_VALUE (list);
7025
7026   /* Figure out the type of the construction vtable.  */
7027   type = build_index_type (size_int (list_length (inits) - 1));
7028   type = build_cplus_array_type (vtable_entry_type, type);
7029   TREE_TYPE (vtbl) = type;
7030
7031   /* Initialize the construction vtable.  */
7032   CLASSTYPE_VTABLES (t) = chainon (CLASSTYPE_VTABLES (t), vtbl);
7033   initialize_artificial_var (vtbl, inits);
7034   dump_vtable (t, binfo, vtbl);
7035 }
7036
7037 /* Add the vtbl initializers for BINFO (and its bases other than
7038    non-virtual primaries) to the list of INITS.  BINFO is in the
7039    hierarchy dominated by T.  RTTI_BINFO is the binfo within T of
7040    the constructor the vtbl inits should be accumulated for. (If this
7041    is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
7042    ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
7043    BINFO is the active base equivalent of ORIG_BINFO in the inheritance
7044    graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
7045    but are not necessarily the same in terms of layout.  */
7046
7047 static void
7048 accumulate_vtbl_inits (tree binfo,
7049                        tree orig_binfo,
7050                        tree rtti_binfo,
7051                        tree t,
7052                        tree inits)
7053 {
7054   int i;
7055   tree base_binfo;
7056   int ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
7057
7058   gcc_assert (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), BINFO_TYPE (orig_binfo)));
7059
7060   /* If it doesn't have a vptr, we don't do anything.  */
7061   if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
7062     return;
7063
7064   /* If we're building a construction vtable, we're not interested in
7065      subobjects that don't require construction vtables.  */
7066   if (ctor_vtbl_p
7067       && !CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo))
7068       && !binfo_via_virtual (orig_binfo, BINFO_TYPE (rtti_binfo)))
7069     return;
7070
7071   /* Build the initializers for the BINFO-in-T vtable.  */
7072   TREE_VALUE (inits)
7073     = chainon (TREE_VALUE (inits),
7074                dfs_accumulate_vtbl_inits (binfo, orig_binfo,
7075                                           rtti_binfo, t, inits));
7076
7077   /* Walk the BINFO and its bases.  We walk in preorder so that as we
7078      initialize each vtable we can figure out at what offset the
7079      secondary vtable lies from the primary vtable.  We can't use
7080      dfs_walk here because we need to iterate through bases of BINFO
7081      and RTTI_BINFO simultaneously.  */
7082   for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
7083     {
7084       /* Skip virtual bases.  */
7085       if (BINFO_VIRTUAL_P (base_binfo))
7086         continue;
7087       accumulate_vtbl_inits (base_binfo,
7088                              BINFO_BASE_BINFO (orig_binfo, i),
7089                              rtti_binfo, t,
7090                              inits);
7091     }
7092 }
7093
7094 /* Called from accumulate_vtbl_inits.  Returns the initializers for
7095    the BINFO vtable.  */
7096
7097 static tree
7098 dfs_accumulate_vtbl_inits (tree binfo,
7099                            tree orig_binfo,
7100                            tree rtti_binfo,
7101                            tree t,
7102                            tree l)
7103 {
7104   tree inits = NULL_TREE;
7105   tree vtbl = NULL_TREE;
7106   int ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
7107
7108   if (ctor_vtbl_p
7109       && BINFO_VIRTUAL_P (orig_binfo) && BINFO_PRIMARY_P (orig_binfo))
7110     {
7111       /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
7112          primary virtual base.  If it is not the same primary in
7113          the hierarchy of T, we'll need to generate a ctor vtable
7114          for it, to place at its location in T.  If it is the same
7115          primary, we still need a VTT entry for the vtable, but it
7116          should point to the ctor vtable for the base it is a
7117          primary for within the sub-hierarchy of RTTI_BINFO.
7118
7119          There are three possible cases:
7120
7121          1) We are in the same place.
7122          2) We are a primary base within a lost primary virtual base of
7123          RTTI_BINFO.
7124          3) We are primary to something not a base of RTTI_BINFO.  */
7125
7126       tree b;
7127       tree last = NULL_TREE;
7128
7129       /* First, look through the bases we are primary to for RTTI_BINFO
7130          or a virtual base.  */
7131       b = binfo;
7132       while (BINFO_PRIMARY_P (b))
7133         {
7134           b = BINFO_INHERITANCE_CHAIN (b);
7135           last = b;
7136           if (BINFO_VIRTUAL_P (b) || b == rtti_binfo)
7137             goto found;
7138         }
7139       /* If we run out of primary links, keep looking down our
7140          inheritance chain; we might be an indirect primary.  */
7141       for (b = last; b; b = BINFO_INHERITANCE_CHAIN (b))
7142         if (BINFO_VIRTUAL_P (b) || b == rtti_binfo)
7143           break;
7144     found:
7145
7146       /* If we found RTTI_BINFO, this is case 1.  If we found a virtual
7147          base B and it is a base of RTTI_BINFO, this is case 2.  In
7148          either case, we share our vtable with LAST, i.e. the
7149          derived-most base within B of which we are a primary.  */
7150       if (b == rtti_binfo
7151           || (b && binfo_for_vbase (BINFO_TYPE (b), BINFO_TYPE (rtti_binfo))))
7152         /* Just set our BINFO_VTABLE to point to LAST, as we may not have
7153            set LAST's BINFO_VTABLE yet.  We'll extract the actual vptr in
7154            binfo_ctor_vtable after everything's been set up.  */
7155         vtbl = last;
7156
7157       /* Otherwise, this is case 3 and we get our own.  */
7158     }
7159   else if (!BINFO_NEW_VTABLE_MARKED (orig_binfo))
7160     return inits;
7161
7162   if (!vtbl)
7163     {
7164       tree index;
7165       int non_fn_entries;
7166
7167       /* Compute the initializer for this vtable.  */
7168       inits = build_vtbl_initializer (binfo, orig_binfo, t, rtti_binfo,
7169                                       &non_fn_entries);
7170
7171       /* Figure out the position to which the VPTR should point.  */
7172       vtbl = TREE_PURPOSE (l);
7173       vtbl = build1 (ADDR_EXPR, vtbl_ptr_type_node, vtbl);
7174       index = size_binop (PLUS_EXPR,
7175                           size_int (non_fn_entries),
7176                           size_int (list_length (TREE_VALUE (l))));
7177       index = size_binop (MULT_EXPR,
7178                           TYPE_SIZE_UNIT (vtable_entry_type),
7179                           index);
7180       vtbl = build2 (PLUS_EXPR, TREE_TYPE (vtbl), vtbl, index);
7181     }
7182
7183   if (ctor_vtbl_p)
7184     /* For a construction vtable, we can't overwrite BINFO_VTABLE.
7185        So, we make a TREE_LIST.  Later, dfs_fixup_binfo_vtbls will
7186        straighten this out.  */
7187     BINFO_VTABLE (binfo) = tree_cons (rtti_binfo, vtbl, BINFO_VTABLE (binfo));
7188   else if (BINFO_PRIMARY_P (binfo) && BINFO_VIRTUAL_P (binfo))
7189     inits = NULL_TREE;
7190   else
7191      /* For an ordinary vtable, set BINFO_VTABLE.  */
7192     BINFO_VTABLE (binfo) = vtbl;
7193
7194   return inits;
7195 }
7196
7197 static GTY(()) tree abort_fndecl_addr;
7198
7199 /* Construct the initializer for BINFO's virtual function table.  BINFO
7200    is part of the hierarchy dominated by T.  If we're building a
7201    construction vtable, the ORIG_BINFO is the binfo we should use to
7202    find the actual function pointers to put in the vtable - but they
7203    can be overridden on the path to most-derived in the graph that
7204    ORIG_BINFO belongs.  Otherwise,
7205    ORIG_BINFO should be the same as BINFO.  The RTTI_BINFO is the
7206    BINFO that should be indicated by the RTTI information in the
7207    vtable; it will be a base class of T, rather than T itself, if we
7208    are building a construction vtable.
7209
7210    The value returned is a TREE_LIST suitable for wrapping in a
7211    CONSTRUCTOR to use as the DECL_INITIAL for a vtable.  If
7212    NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
7213    number of non-function entries in the vtable.
7214
7215    It might seem that this function should never be called with a
7216    BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
7217    base is always subsumed by a derived class vtable.  However, when
7218    we are building construction vtables, we do build vtables for
7219    primary bases; we need these while the primary base is being
7220    constructed.  */
7221
7222 static tree
7223 build_vtbl_initializer (tree binfo,
7224                         tree orig_binfo,
7225                         tree t,
7226                         tree rtti_binfo,
7227                         int* non_fn_entries_p)
7228 {
7229   tree v, b;
7230   tree vfun_inits;
7231   vtbl_init_data vid;
7232   unsigned ix;
7233   tree vbinfo;
7234   VEC(tree,gc) *vbases;
7235
7236   /* Initialize VID.  */
7237   memset (&vid, 0, sizeof (vid));
7238   vid.binfo = binfo;
7239   vid.derived = t;
7240   vid.rtti_binfo = rtti_binfo;
7241   vid.last_init = &vid.inits;
7242   vid.primary_vtbl_p = SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t);
7243   vid.ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
7244   vid.generate_vcall_entries = true;
7245   /* The first vbase or vcall offset is at index -3 in the vtable.  */
7246   vid.index = ssize_int(-3 * TARGET_VTABLE_DATA_ENTRY_DISTANCE);
7247
7248   /* Add entries to the vtable for RTTI.  */
7249   build_rtti_vtbl_entries (binfo, &vid);
7250
7251   /* Create an array for keeping track of the functions we've
7252      processed.  When we see multiple functions with the same
7253      signature, we share the vcall offsets.  */
7254   vid.fns = VEC_alloc (tree, gc, 32);
7255   /* Add the vcall and vbase offset entries.  */
7256   build_vcall_and_vbase_vtbl_entries (binfo, &vid);
7257
7258   /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
7259      build_vbase_offset_vtbl_entries.  */
7260   for (vbases = CLASSTYPE_VBASECLASSES (t), ix = 0;
7261        VEC_iterate (tree, vbases, ix, vbinfo); ix++)
7262     BINFO_VTABLE_PATH_MARKED (vbinfo) = 0;
7263
7264   /* If the target requires padding between data entries, add that now.  */
7265   if (TARGET_VTABLE_DATA_ENTRY_DISTANCE > 1)
7266     {
7267       tree cur, *prev;
7268
7269       for (prev = &vid.inits; (cur = *prev); prev = &TREE_CHAIN (cur))
7270         {
7271           tree add = cur;
7272           int i;
7273
7274           for (i = 1; i < TARGET_VTABLE_DATA_ENTRY_DISTANCE; ++i)
7275             add = tree_cons (NULL_TREE,
7276                              build1 (NOP_EXPR, vtable_entry_type,
7277                                      null_pointer_node),
7278                              add);
7279           *prev = add;
7280         }
7281     }
7282
7283   if (non_fn_entries_p)
7284     *non_fn_entries_p = list_length (vid.inits);
7285
7286   /* Go through all the ordinary virtual functions, building up
7287      initializers.  */
7288   vfun_inits = NULL_TREE;
7289   for (v = BINFO_VIRTUALS (orig_binfo); v; v = TREE_CHAIN (v))
7290     {
7291       tree delta;
7292       tree vcall_index;
7293       tree fn, fn_original;
7294       tree init = NULL_TREE;
7295
7296       fn = BV_FN (v);
7297       fn_original = fn;
7298       if (DECL_THUNK_P (fn))
7299         {
7300           if (!DECL_NAME (fn))
7301             finish_thunk (fn);
7302           if (THUNK_ALIAS (fn))
7303             {
7304               fn = THUNK_ALIAS (fn);
7305               BV_FN (v) = fn;
7306             }
7307           fn_original = THUNK_TARGET (fn);
7308         }
7309
7310       /* If the only definition of this function signature along our
7311          primary base chain is from a lost primary, this vtable slot will
7312          never be used, so just zero it out.  This is important to avoid
7313          requiring extra thunks which cannot be generated with the function.
7314
7315          We first check this in update_vtable_entry_for_fn, so we handle
7316          restored primary bases properly; we also need to do it here so we
7317          zero out unused slots in ctor vtables, rather than filling themff
7318          with erroneous values (though harmless, apart from relocation
7319          costs).  */
7320       for (b = binfo; ; b = get_primary_binfo (b))
7321         {
7322           /* We found a defn before a lost primary; go ahead as normal.  */
7323           if (look_for_overrides_here (BINFO_TYPE (b), fn_original))
7324             break;
7325
7326           /* The nearest definition is from a lost primary; clear the
7327              slot.  */
7328           if (BINFO_LOST_PRIMARY_P (b))
7329             {
7330               init = size_zero_node;
7331               break;
7332             }
7333         }
7334
7335       if (! init)
7336         {
7337           /* Pull the offset for `this', and the function to call, out of
7338              the list.  */
7339           delta = BV_DELTA (v);
7340           vcall_index = BV_VCALL_INDEX (v);
7341
7342           gcc_assert (TREE_CODE (delta) == INTEGER_CST);
7343           gcc_assert (TREE_CODE (fn) == FUNCTION_DECL);
7344
7345           /* You can't call an abstract virtual function; it's abstract.
7346              So, we replace these functions with __pure_virtual.  */
7347           if (DECL_PURE_VIRTUAL_P (fn_original))
7348             {
7349               fn = abort_fndecl;
7350               if (abort_fndecl_addr == NULL)
7351                 abort_fndecl_addr = build1 (ADDR_EXPR, vfunc_ptr_type_node, fn);
7352               init = abort_fndecl_addr;
7353             }
7354           else
7355             {
7356               if (!integer_zerop (delta) || vcall_index)
7357                 {
7358                   fn = make_thunk (fn, /*this_adjusting=*/1, delta, vcall_index);
7359                   if (!DECL_NAME (fn))
7360                     finish_thunk (fn);
7361                 }
7362               /* Take the address of the function, considering it to be of an
7363                  appropriate generic type.  */
7364               init = build1 (ADDR_EXPR, vfunc_ptr_type_node, fn);
7365             }
7366         }
7367
7368       /* And add it to the chain of initializers.  */
7369       if (TARGET_VTABLE_USES_DESCRIPTORS)
7370         {
7371           int i;
7372           if (init == size_zero_node)
7373             for (i = 0; i < TARGET_VTABLE_USES_DESCRIPTORS; ++i)
7374               vfun_inits = tree_cons (NULL_TREE, init, vfun_inits);
7375           else
7376             for (i = 0; i < TARGET_VTABLE_USES_DESCRIPTORS; ++i)
7377               {
7378                 tree fdesc = build2 (FDESC_EXPR, vfunc_ptr_type_node,
7379                                      TREE_OPERAND (init, 0),
7380                                      build_int_cst (NULL_TREE, i));
7381                 TREE_CONSTANT (fdesc) = 1;
7382                 TREE_INVARIANT (fdesc) = 1;
7383
7384                 vfun_inits = tree_cons (NULL_TREE, fdesc, vfun_inits);
7385               }
7386         }
7387       else
7388         vfun_inits = tree_cons (NULL_TREE, init, vfun_inits);
7389     }
7390
7391   /* The initializers for virtual functions were built up in reverse
7392      order; straighten them out now.  */
7393   vfun_inits = nreverse (vfun_inits);
7394
7395   /* The negative offset initializers are also in reverse order.  */
7396   vid.inits = nreverse (vid.inits);
7397
7398   /* Chain the two together.  */
7399   return chainon (vid.inits, vfun_inits);
7400 }
7401
7402 /* Adds to vid->inits the initializers for the vbase and vcall
7403    offsets in BINFO, which is in the hierarchy dominated by T.  */
7404
7405 static void
7406 build_vcall_and_vbase_vtbl_entries (tree binfo, vtbl_init_data* vid)
7407 {
7408   tree b;
7409
7410   /* If this is a derived class, we must first create entries
7411      corresponding to the primary base class.  */
7412   b = get_primary_binfo (binfo);
7413   if (b)
7414     build_vcall_and_vbase_vtbl_entries (b, vid);
7415
7416   /* Add the vbase entries for this base.  */
7417   build_vbase_offset_vtbl_entries (binfo, vid);
7418   /* Add the vcall entries for this base.  */
7419   build_vcall_offset_vtbl_entries (binfo, vid);
7420 }
7421
7422 /* Returns the initializers for the vbase offset entries in the vtable
7423    for BINFO (which is part of the class hierarchy dominated by T), in
7424    reverse order.  VBASE_OFFSET_INDEX gives the vtable index
7425    where the next vbase offset will go.  */
7426
7427 static void
7428 build_vbase_offset_vtbl_entries (tree binfo, vtbl_init_data* vid)
7429 {
7430   tree vbase;
7431   tree t;
7432   tree non_primary_binfo;
7433
7434   /* If there are no virtual baseclasses, then there is nothing to
7435      do.  */
7436   if (!CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo)))
7437     return;
7438
7439   t = vid->derived;
7440
7441   /* We might be a primary base class.  Go up the inheritance hierarchy
7442      until we find the most derived class of which we are a primary base:
7443      it is the offset of that which we need to use.  */
7444   non_primary_binfo = binfo;
7445   while (BINFO_INHERITANCE_CHAIN (non_primary_binfo))
7446     {
7447       tree b;
7448
7449       /* If we have reached a virtual base, then it must be a primary
7450          base (possibly multi-level) of vid->binfo, or we wouldn't
7451          have called build_vcall_and_vbase_vtbl_entries for it.  But it
7452          might be a lost primary, so just skip down to vid->binfo.  */
7453       if (BINFO_VIRTUAL_P (non_primary_binfo))
7454         {
7455           non_primary_binfo = vid->binfo;
7456           break;
7457         }
7458
7459       b = BINFO_INHERITANCE_CHAIN (non_primary_binfo);
7460       if (get_primary_binfo (b) != non_primary_binfo)
7461         break;
7462       non_primary_binfo = b;
7463     }
7464
7465   /* Go through the virtual bases, adding the offsets.  */
7466   for (vbase = TYPE_BINFO (BINFO_TYPE (binfo));
7467        vbase;
7468        vbase = TREE_CHAIN (vbase))
7469     {
7470       tree b;
7471       tree delta;
7472
7473       if (!BINFO_VIRTUAL_P (vbase))
7474         continue;
7475
7476       /* Find the instance of this virtual base in the complete
7477          object.  */
7478       b = copied_binfo (vbase, binfo);
7479
7480       /* If we've already got an offset for this virtual base, we
7481          don't need another one.  */
7482       if (BINFO_VTABLE_PATH_MARKED (b))
7483         continue;
7484       BINFO_VTABLE_PATH_MARKED (b) = 1;
7485
7486       /* Figure out where we can find this vbase offset.  */
7487       delta = size_binop (MULT_EXPR,
7488                           vid->index,
7489                           convert (ssizetype,
7490                                    TYPE_SIZE_UNIT (vtable_entry_type)));
7491       if (vid->primary_vtbl_p)
7492         BINFO_VPTR_FIELD (b) = delta;
7493
7494       if (binfo != TYPE_BINFO (t))
7495         /* The vbase offset had better be the same.  */
7496         gcc_assert (tree_int_cst_equal (delta, BINFO_VPTR_FIELD (vbase)));
7497
7498       /* The next vbase will come at a more negative offset.  */
7499       vid->index = size_binop (MINUS_EXPR, vid->index,
7500                                ssize_int (TARGET_VTABLE_DATA_ENTRY_DISTANCE));
7501
7502       /* The initializer is the delta from BINFO to this virtual base.
7503          The vbase offsets go in reverse inheritance-graph order, and
7504          we are walking in inheritance graph order so these end up in
7505          the right order.  */
7506       delta = size_diffop (BINFO_OFFSET (b), BINFO_OFFSET (non_primary_binfo));
7507
7508       *vid->last_init
7509         = build_tree_list (NULL_TREE,
7510                            fold_build1 (NOP_EXPR,
7511                                         vtable_entry_type,
7512                                         delta));
7513       vid->last_init = &TREE_CHAIN (*vid->last_init);
7514     }
7515 }
7516
7517 /* Adds the initializers for the vcall offset entries in the vtable
7518    for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
7519    to VID->INITS.  */
7520
7521 static void
7522 build_vcall_offset_vtbl_entries (tree binfo, vtbl_init_data* vid)
7523 {
7524   /* We only need these entries if this base is a virtual base.  We
7525      compute the indices -- but do not add to the vtable -- when
7526      building the main vtable for a class.  */
7527   if (BINFO_VIRTUAL_P (binfo) || binfo == TYPE_BINFO (vid->derived))
7528     {
7529       /* We need a vcall offset for each of the virtual functions in this
7530          vtable.  For example:
7531
7532            class A { virtual void f (); };
7533            class B1 : virtual public A { virtual void f (); };
7534            class B2 : virtual public A { virtual void f (); };
7535            class C: public B1, public B2 { virtual void f (); };
7536
7537          A C object has a primary base of B1, which has a primary base of A.  A
7538          C also has a secondary base of B2, which no longer has a primary base
7539          of A.  So the B2-in-C construction vtable needs a secondary vtable for
7540          A, which will adjust the A* to a B2* to call f.  We have no way of
7541          knowing what (or even whether) this offset will be when we define B2,
7542          so we store this "vcall offset" in the A sub-vtable and look it up in
7543          a "virtual thunk" for B2::f.
7544
7545          We need entries for all the functions in our primary vtable and
7546          in our non-virtual bases' secondary vtables.  */
7547       vid->vbase = binfo;
7548       /* If we are just computing the vcall indices -- but do not need
7549          the actual entries -- not that.  */
7550       if (!BINFO_VIRTUAL_P (binfo))
7551         vid->generate_vcall_entries = false;
7552       /* Now, walk through the non-virtual bases, adding vcall offsets.  */
7553       add_vcall_offset_vtbl_entries_r (binfo, vid);
7554     }
7555 }
7556
7557 /* Build vcall offsets, starting with those for BINFO.  */
7558
7559 static void
7560 add_vcall_offset_vtbl_entries_r (tree binfo, vtbl_init_data* vid)
7561 {
7562   int i;
7563   tree primary_binfo;
7564   tree base_binfo;
7565
7566   /* Don't walk into virtual bases -- except, of course, for the
7567      virtual base for which we are building vcall offsets.  Any
7568      primary virtual base will have already had its offsets generated
7569      through the recursion in build_vcall_and_vbase_vtbl_entries.  */
7570   if (BINFO_VIRTUAL_P (binfo) && vid->vbase != binfo)
7571     return;
7572
7573   /* If BINFO has a primary base, process it first.  */
7574   primary_binfo = get_primary_binfo (binfo);
7575   if (primary_binfo)
7576     add_vcall_offset_vtbl_entries_r (primary_binfo, vid);
7577
7578   /* Add BINFO itself to the list.  */
7579   add_vcall_offset_vtbl_entries_1 (binfo, vid);
7580
7581   /* Scan the non-primary bases of BINFO.  */
7582   for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
7583     if (base_binfo != primary_binfo)
7584       add_vcall_offset_vtbl_entries_r (base_binfo, vid);
7585 }
7586
7587 /* Called from build_vcall_offset_vtbl_entries_r.  */
7588
7589 static void
7590 add_vcall_offset_vtbl_entries_1 (tree binfo, vtbl_init_data* vid)
7591 {
7592   /* Make entries for the rest of the virtuals.  */
7593   if (abi_version_at_least (2))
7594     {
7595       tree orig_fn;
7596
7597       /* The ABI requires that the methods be processed in declaration
7598          order.  G++ 3.2 used the order in the vtable.  */
7599       for (orig_fn = TYPE_METHODS (BINFO_TYPE (binfo));
7600            orig_fn;
7601            orig_fn = TREE_CHAIN (orig_fn))
7602         if (DECL_VINDEX (orig_fn))
7603           add_vcall_offset (orig_fn, binfo, vid);
7604     }
7605   else
7606     {
7607       tree derived_virtuals;
7608       tree base_virtuals;
7609       tree orig_virtuals;
7610       /* If BINFO is a primary base, the most derived class which has
7611          BINFO as a primary base; otherwise, just BINFO.  */
7612       tree non_primary_binfo;
7613
7614       /* We might be a primary base class.  Go up the inheritance hierarchy
7615          until we find the most derived class of which we are a primary base:
7616          it is the BINFO_VIRTUALS there that we need to consider.  */
7617       non_primary_binfo = binfo;
7618       while (BINFO_INHERITANCE_CHAIN (non_primary_binfo))
7619         {
7620           tree b;
7621
7622           /* If we have reached a virtual base, then it must be vid->vbase,
7623              because we ignore other virtual bases in
7624              add_vcall_offset_vtbl_entries_r.  In turn, it must be a primary
7625              base (possibly multi-level) of vid->binfo, or we wouldn't
7626              have called build_vcall_and_vbase_vtbl_entries for it.  But it
7627              might be a lost primary, so just skip down to vid->binfo.  */
7628           if (BINFO_VIRTUAL_P (non_primary_binfo))
7629             {
7630               gcc_assert (non_primary_binfo == vid->vbase);
7631               non_primary_binfo = vid->binfo;
7632               break;
7633             }
7634
7635           b = BINFO_INHERITANCE_CHAIN (non_primary_binfo);
7636           if (get_primary_binfo (b) != non_primary_binfo)
7637             break;
7638           non_primary_binfo = b;
7639         }
7640
7641       if (vid->ctor_vtbl_p)
7642         /* For a ctor vtable we need the equivalent binfo within the hierarchy
7643            where rtti_binfo is the most derived type.  */
7644         non_primary_binfo
7645           = original_binfo (non_primary_binfo, vid->rtti_binfo);
7646
7647       for (base_virtuals = BINFO_VIRTUALS (binfo),
7648              derived_virtuals = BINFO_VIRTUALS (non_primary_binfo),
7649              orig_virtuals = BINFO_VIRTUALS (TYPE_BINFO (BINFO_TYPE (binfo)));
7650            base_virtuals;
7651            base_virtuals = TREE_CHAIN (base_virtuals),
7652              derived_virtuals = TREE_CHAIN (derived_virtuals),
7653              orig_virtuals = TREE_CHAIN (orig_virtuals))
7654         {
7655           tree orig_fn;
7656
7657           /* Find the declaration that originally caused this function to
7658              be present in BINFO_TYPE (binfo).  */
7659           orig_fn = BV_FN (orig_virtuals);
7660
7661           /* When processing BINFO, we only want to generate vcall slots for
7662              function slots introduced in BINFO.  So don't try to generate
7663              one if the function isn't even defined in BINFO.  */
7664           if (!SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), DECL_CONTEXT (orig_fn)))
7665             continue;
7666
7667           add_vcall_offset (orig_fn, binfo, vid);
7668         }
7669     }
7670 }
7671
7672 /* Add a vcall offset entry for ORIG_FN to the vtable.  */
7673
7674 static void
7675 add_vcall_offset (tree orig_fn, tree binfo, vtbl_init_data *vid)
7676 {
7677   size_t i;
7678   tree vcall_offset;
7679   tree derived_entry;
7680
7681   /* If there is already an entry for a function with the same
7682      signature as FN, then we do not need a second vcall offset.
7683      Check the list of functions already present in the derived
7684      class vtable.  */
7685   for (i = 0; VEC_iterate (tree, vid->fns, i, derived_entry); ++i)
7686     {
7687       if (same_signature_p (derived_entry, orig_fn)
7688           /* We only use one vcall offset for virtual destructors,
7689              even though there are two virtual table entries.  */
7690           || (DECL_DESTRUCTOR_P (derived_entry)
7691               && DECL_DESTRUCTOR_P (orig_fn)))
7692         return;
7693     }
7694
7695   /* If we are building these vcall offsets as part of building
7696      the vtable for the most derived class, remember the vcall
7697      offset.  */
7698   if (vid->binfo == TYPE_BINFO (vid->derived))
7699     {
7700       tree_pair_p elt = VEC_safe_push (tree_pair_s, gc,
7701                                        CLASSTYPE_VCALL_INDICES (vid->derived),
7702                                        NULL);
7703       elt->purpose = orig_fn;
7704       elt->value = vid->index;
7705     }
7706
7707   /* The next vcall offset will be found at a more negative
7708      offset.  */
7709   vid->index = size_binop (MINUS_EXPR, vid->index,
7710                            ssize_int (TARGET_VTABLE_DATA_ENTRY_DISTANCE));
7711
7712   /* Keep track of this function.  */
7713   VEC_safe_push (tree, gc, vid->fns, orig_fn);
7714
7715   if (vid->generate_vcall_entries)
7716     {
7717       tree base;
7718       tree fn;
7719
7720       /* Find the overriding function.  */
7721       fn = find_final_overrider (vid->rtti_binfo, binfo, orig_fn);
7722       if (fn == error_mark_node)
7723         vcall_offset = build1 (NOP_EXPR, vtable_entry_type,
7724                                integer_zero_node);
7725       else
7726         {
7727           base = TREE_VALUE (fn);
7728
7729           /* The vbase we're working on is a primary base of
7730              vid->binfo.  But it might be a lost primary, so its
7731              BINFO_OFFSET might be wrong, so we just use the
7732              BINFO_OFFSET from vid->binfo.  */
7733           vcall_offset = size_diffop (BINFO_OFFSET (base),
7734                                       BINFO_OFFSET (vid->binfo));
7735           vcall_offset = fold_build1 (NOP_EXPR, vtable_entry_type,
7736                                       vcall_offset);
7737         }
7738       /* Add the initializer to the vtable.  */
7739       *vid->last_init = build_tree_list (NULL_TREE, vcall_offset);
7740       vid->last_init = &TREE_CHAIN (*vid->last_init);
7741     }
7742 }
7743
7744 /* Return vtbl initializers for the RTTI entries corresponding to the
7745    BINFO's vtable.  The RTTI entries should indicate the object given
7746    by VID->rtti_binfo.  */
7747
7748 static void
7749 build_rtti_vtbl_entries (tree binfo, vtbl_init_data* vid)
7750 {
7751   tree b;
7752   tree t;
7753   tree basetype;
7754   tree offset;
7755   tree decl;
7756   tree init;
7757
7758   basetype = BINFO_TYPE (binfo);
7759   t = BINFO_TYPE (vid->rtti_binfo);
7760
7761   /* To find the complete object, we will first convert to our most
7762      primary base, and then add the offset in the vtbl to that value.  */
7763   b = binfo;
7764   while (CLASSTYPE_HAS_PRIMARY_BASE_P (BINFO_TYPE (b))
7765          && !BINFO_LOST_PRIMARY_P (b))
7766     {
7767       tree primary_base;
7768
7769       primary_base = get_primary_binfo (b);
7770       gcc_assert (BINFO_PRIMARY_P (primary_base)
7771                   && BINFO_INHERITANCE_CHAIN (primary_base) == b);
7772       b = primary_base;
7773     }
7774   offset = size_diffop (BINFO_OFFSET (vid->rtti_binfo), BINFO_OFFSET (b));
7775
7776   /* The second entry is the address of the typeinfo object.  */
7777   if (flag_rtti)
7778     decl = build_address (get_tinfo_decl (t));
7779   else
7780     decl = integer_zero_node;
7781
7782   /* Convert the declaration to a type that can be stored in the
7783      vtable.  */
7784   init = build_nop (vfunc_ptr_type_node, decl);
7785   *vid->last_init = build_tree_list (NULL_TREE, init);
7786   vid->last_init = &TREE_CHAIN (*vid->last_init);
7787
7788   /* Add the offset-to-top entry.  It comes earlier in the vtable than
7789      the typeinfo entry.  Convert the offset to look like a
7790      function pointer, so that we can put it in the vtable.  */
7791   init = build_nop (vfunc_ptr_type_node, offset);
7792   *vid->last_init = build_tree_list (NULL_TREE, init);
7793   vid->last_init = &TREE_CHAIN (*vid->last_init);
7794 }
7795
7796 /* Fold a OBJ_TYPE_REF expression to the address of a function.
7797    KNOWN_TYPE carries the true type of OBJ_TYPE_REF_OBJECT(REF).  */
7798
7799 tree
7800 cp_fold_obj_type_ref (tree ref, tree known_type)
7801 {
7802   HOST_WIDE_INT index = tree_low_cst (OBJ_TYPE_REF_TOKEN (ref), 1);
7803   HOST_WIDE_INT i = 0;
7804   tree v = BINFO_VIRTUALS (TYPE_BINFO (known_type));
7805   tree fndecl;
7806
7807   while (i != index)
7808     {
7809       i += (TARGET_VTABLE_USES_DESCRIPTORS
7810             ? TARGET_VTABLE_USES_DESCRIPTORS : 1);
7811       v = TREE_CHAIN (v);
7812     }
7813
7814   fndecl = BV_FN (v);
7815
7816 #ifdef ENABLE_CHECKING
7817   gcc_assert (tree_int_cst_equal (OBJ_TYPE_REF_TOKEN (ref),
7818                                   DECL_VINDEX (fndecl)));
7819 #endif
7820
7821   cgraph_node (fndecl)->local.vtable_method = true;
7822
7823   return build_address (fndecl);
7824 }
7825
7826 #include "gt-cp-class.h"