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 ([email protected])
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 build_simple_base_path (tree expr, tree binfo);
138 static tree build_vtbl_ref_1 (tree, tree);
139 static tree build_vtbl_initializer (tree, tree, tree, tree, int *);
140 static int count_fields (tree);
141 static int add_fields_to_record_type (tree, struct sorted_fields_type*, int);
142 static void check_bitfield_decl (tree);
143 static void check_field_decl (tree, tree, int *, int *, int *);
144 static void check_field_decls (tree, tree *, int *, int *);
145 static tree *build_base_field (record_layout_info, tree, splay_tree, tree *);
146 static void build_base_fields (record_layout_info, splay_tree, tree *);
147 static void check_methods (tree);
148 static void remove_zero_width_bit_fields (tree);
149 static void check_bases (tree, int *, int *);
150 static void check_bases_and_members (tree);
151 static tree create_vtable_ptr (tree, tree *);
152 static void include_empty_classes (record_layout_info);
153 static void layout_class_type (tree, tree *);
154 static void fixup_pending_inline (tree);
155 static void fixup_inline_methods (tree);
156 static void propagate_binfo_offsets (tree, tree);
157 static void layout_virtual_bases (record_layout_info, splay_tree);
158 static void build_vbase_offset_vtbl_entries (tree, vtbl_init_data *);
159 static void add_vcall_offset_vtbl_entries_r (tree, vtbl_init_data *);
160 static void add_vcall_offset_vtbl_entries_1 (tree, vtbl_init_data *);
161 static void build_vcall_offset_vtbl_entries (tree, vtbl_init_data *);
162 static void add_vcall_offset (tree, tree, vtbl_init_data *);
163 static void layout_vtable_decl (tree, int);
164 static tree dfs_find_final_overrider_pre (tree, void *);
165 static tree dfs_find_final_overrider_post (tree, void *);
166 static tree find_final_overrider (tree, tree, tree);
167 static int make_new_vtable (tree, tree);
168 static tree get_primary_binfo (tree);
169 static int maybe_indent_hierarchy (FILE *, int, int);
170 static tree dump_class_hierarchy_r (FILE *, int, tree, tree, int);
171 static void dump_class_hierarchy (tree);
172 static void dump_class_hierarchy_1 (FILE *, int, tree);
173 static void dump_array (FILE *, tree);
174 static void dump_vtable (tree, tree, tree);
175 static void dump_vtt (tree, tree);
176 static void dump_thunk (FILE *, int, tree);
177 static tree build_vtable (tree, tree, tree);
178 static void initialize_vtable (tree, tree);
179 static void layout_nonempty_base_or_field (record_layout_info,
180 tree, tree, splay_tree);
181 static tree end_of_class (tree, int);
182 static bool layout_empty_base (tree, tree, splay_tree);
183 static void accumulate_vtbl_inits (tree, tree, tree, tree, tree);
184 static tree dfs_accumulate_vtbl_inits (tree, tree, tree, tree,
185 tree);
186 static void build_rtti_vtbl_entries (tree, vtbl_init_data *);
187 static void build_vcall_and_vbase_vtbl_entries (tree, vtbl_init_data *);
188 static void clone_constructors_and_destructors (tree);
189 static tree build_clone (tree, tree);
190 static void update_vtable_entry_for_fn (tree, tree, tree, tree *, unsigned);
191 static void build_ctor_vtbl_group (tree, tree);
192 static void build_vtt (tree);
193 static tree binfo_ctor_vtable (tree);
194 static tree *build_vtt_inits (tree, tree, tree *, tree *);
195 static tree dfs_build_secondary_vptr_vtt_inits (tree, void *);
196 static tree dfs_fixup_binfo_vtbls (tree, void *);
197 static int record_subobject_offset (tree, tree, splay_tree);
198 static int check_subobject_offset (tree, tree, splay_tree);
199 static int walk_subobject_offsets (tree, subobject_offset_fn,
200 tree, splay_tree, tree, int);
201 static void record_subobject_offsets (tree, tree, splay_tree, bool);
202 static int layout_conflict_p (tree, tree, splay_tree, int);
203 static int splay_tree_compare_integer_csts (splay_tree_key k1,
204 splay_tree_key k2);
205 static void warn_about_ambiguous_bases (tree);
206 static bool type_requires_array_cookie (tree);
207 static bool contains_empty_class_p (tree);
208 static bool base_derived_from (tree, tree);
209 static int empty_base_at_nonzero_offset_p (tree, tree, splay_tree);
210 static tree end_of_base (tree);
211 static tree get_vcall_index (tree, tree);
212
213 /* Variables shared between class.c and call.c. */
214
215 #ifdef GATHER_STATISTICS
216 int n_vtables = 0;
217 int n_vtable_entries = 0;
218 int n_vtable_searches = 0;
219 int n_vtable_elems = 0;
220 int n_convert_harshness = 0;
221 int n_compute_conversion_costs = 0;
222 int n_inner_fields_searched = 0;
223 #endif
224
225 /* Convert to or from a base subobject. EXPR is an expression of type
226 `A' or `A*', an expression of type `B' or `B*' is returned. To
227 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
228 the B base instance within A. To convert base A to derived B, CODE
229 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
230 In this latter case, A must not be a morally virtual base of B.
231 NONNULL is true if EXPR is known to be non-NULL (this is only
232 needed when EXPR is of pointer type). CV qualifiers are preserved
233 from EXPR. */
234
235 tree
build_base_path(enum tree_code code,tree expr,tree binfo,int nonnull)236 build_base_path (enum tree_code code,
237 tree expr,
238 tree binfo,
239 int nonnull)
240 {
241 tree v_binfo = NULL_TREE;
242 tree d_binfo = NULL_TREE;
243 tree probe;
244 tree offset;
245 tree target_type;
246 tree null_test = NULL;
247 tree ptr_target_type;
248 int fixed_type_p;
249 int want_pointer = TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE;
250 bool has_empty = false;
251 bool virtual_access;
252
253 if (expr == error_mark_node || binfo == error_mark_node || !binfo)
254 return error_mark_node;
255
256 for (probe = binfo; probe; probe = BINFO_INHERITANCE_CHAIN (probe))
257 {
258 d_binfo = probe;
259 if (is_empty_class (BINFO_TYPE (probe)))
260 has_empty = true;
261 if (!v_binfo && BINFO_VIRTUAL_P (probe))
262 v_binfo = probe;
263 }
264
265 probe = TYPE_MAIN_VARIANT (TREE_TYPE (expr));
266 if (want_pointer)
267 probe = TYPE_MAIN_VARIANT (TREE_TYPE (probe));
268
269 gcc_assert ((code == MINUS_EXPR
270 && SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), probe))
271 || (code == PLUS_EXPR
272 && SAME_BINFO_TYPE_P (BINFO_TYPE (d_binfo), probe)));
273
274 if (binfo == d_binfo)
275 /* Nothing to do. */
276 return expr;
277
278 if (code == MINUS_EXPR && v_binfo)
279 {
280 error ("cannot convert from base %qT to derived type %qT via virtual base %qT",
281 BINFO_TYPE (binfo), BINFO_TYPE (d_binfo), BINFO_TYPE (v_binfo));
282 return error_mark_node;
283 }
284
285 if (!want_pointer)
286 /* This must happen before the call to save_expr. */
287 expr = build_unary_op (ADDR_EXPR, expr, 0);
288
289 offset = BINFO_OFFSET (binfo);
290 fixed_type_p = resolves_to_fixed_type_p (expr, &nonnull);
291 target_type = code == PLUS_EXPR ? BINFO_TYPE (binfo) : BINFO_TYPE (d_binfo);
292
293 /* Do we need to look in the vtable for the real offset? */
294 virtual_access = (v_binfo && fixed_type_p <= 0);
295
296 /* Do we need to check for a null pointer? */
297 if (want_pointer && !nonnull)
298 {
299 /* If we know the conversion will not actually change the value
300 of EXPR, then we can avoid testing the expression for NULL.
301 We have to avoid generating a COMPONENT_REF for a base class
302 field, because other parts of the compiler know that such
303 expressions are always non-NULL. */
304 if (!virtual_access && integer_zerop (offset))
305 {
306 tree class_type;
307 /* TARGET_TYPE has been extracted from BINFO, and, is
308 therefore always cv-unqualified. Extract the
309 cv-qualifiers from EXPR so that the expression returned
310 matches the input. */
311 class_type = TREE_TYPE (TREE_TYPE (expr));
312 target_type
313 = cp_build_qualified_type (target_type,
314 cp_type_quals (class_type));
315 return build_nop (build_pointer_type (target_type), expr);
316 }
317 null_test = error_mark_node;
318 }
319
320 /* Protect against multiple evaluation if necessary. */
321 if (TREE_SIDE_EFFECTS (expr) && (null_test || virtual_access))
322 expr = save_expr (expr);
323
324 /* Now that we've saved expr, build the real null test. */
325 if (null_test)
326 {
327 tree zero = cp_convert (TREE_TYPE (expr), integer_zero_node);
328 null_test = fold_build2 (NE_EXPR, boolean_type_node,
329 expr, zero);
330 }
331
332 /* If this is a simple base reference, express it as a COMPONENT_REF. */
333 if (code == PLUS_EXPR && !virtual_access
334 /* We don't build base fields for empty bases, and they aren't very
335 interesting to the optimizers anyway. */
336 && !has_empty)
337 {
338 expr = build_indirect_ref (expr, NULL);
339 expr = build_simple_base_path (expr, binfo);
340 if (want_pointer)
341 expr = build_address (expr);
342 target_type = TREE_TYPE (expr);
343 goto out;
344 }
345
346 if (virtual_access)
347 {
348 /* Going via virtual base V_BINFO. We need the static offset
349 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
350 V_BINFO. That offset is an entry in D_BINFO's vtable. */
351 tree v_offset;
352
353 if (fixed_type_p < 0 && in_base_initializer)
354 {
355 /* In a base member initializer, we cannot rely on the
356 vtable being set up. We have to indirect via the
357 vtt_parm. */
358 tree t;
359
360 t = TREE_TYPE (TYPE_VFIELD (current_class_type));
361 t = build_pointer_type (t);
362 v_offset = convert (t, current_vtt_parm);
363 v_offset = build_indirect_ref (v_offset, NULL);
364 }
365 else
366 v_offset = build_vfield_ref (build_indirect_ref (expr, NULL),
367 TREE_TYPE (TREE_TYPE (expr)));
368
369 v_offset = build2 (PLUS_EXPR, TREE_TYPE (v_offset),
370 v_offset, BINFO_VPTR_FIELD (v_binfo));
371 v_offset = build1 (NOP_EXPR,
372 build_pointer_type (ptrdiff_type_node),
373 v_offset);
374 v_offset = build_indirect_ref (v_offset, NULL);
375 TREE_CONSTANT (v_offset) = 1;
376 TREE_INVARIANT (v_offset) = 1;
377
378 offset = convert_to_integer (ptrdiff_type_node,
379 size_diffop (offset,
380 BINFO_OFFSET (v_binfo)));
381
382 if (!integer_zerop (offset))
383 v_offset = build2 (code, ptrdiff_type_node, v_offset, offset);
384
385 if (fixed_type_p < 0)
386 /* Negative fixed_type_p means this is a constructor or destructor;
387 virtual base layout is fixed in in-charge [cd]tors, but not in
388 base [cd]tors. */
389 offset = build3 (COND_EXPR, ptrdiff_type_node,
390 build2 (EQ_EXPR, boolean_type_node,
391 current_in_charge_parm, integer_zero_node),
392 v_offset,
393 convert_to_integer (ptrdiff_type_node,
394 BINFO_OFFSET (binfo)));
395 else
396 offset = v_offset;
397 }
398
399 target_type = cp_build_qualified_type
400 (target_type, cp_type_quals (TREE_TYPE (TREE_TYPE (expr))));
401 ptr_target_type = build_pointer_type (target_type);
402 if (want_pointer)
403 target_type = ptr_target_type;
404
405 expr = build1 (NOP_EXPR, ptr_target_type, expr);
406
407 if (!integer_zerop (offset))
408 expr = build2 (code, ptr_target_type, expr, offset);
409 else
410 null_test = NULL;
411
412 if (!want_pointer)
413 expr = build_indirect_ref (expr, NULL);
414
415 out:
416 if (null_test)
417 expr = fold_build3 (COND_EXPR, target_type, null_test, expr,
418 fold_build1 (NOP_EXPR, target_type,
419 integer_zero_node));
420
421 return expr;
422 }
423
424 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
425 Perform a derived-to-base conversion by recursively building up a
426 sequence of COMPONENT_REFs to the appropriate base fields. */
427
428 static tree
build_simple_base_path(tree expr,tree binfo)429 build_simple_base_path (tree expr, tree binfo)
430 {
431 tree type = BINFO_TYPE (binfo);
432 tree d_binfo = BINFO_INHERITANCE_CHAIN (binfo);
433 tree field;
434
435 if (d_binfo == NULL_TREE)
436 {
437 tree temp;
438
439 gcc_assert (TYPE_MAIN_VARIANT (TREE_TYPE (expr)) == type);
440
441 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
442 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
443 an lvalue in the frontend; only _DECLs and _REFs are lvalues
444 in the backend. */
445 temp = unary_complex_lvalue (ADDR_EXPR, expr);
446 if (temp)
447 expr = build_indirect_ref (temp, NULL);
448
449 return expr;
450 }
451
452 /* Recurse. */
453 expr = build_simple_base_path (expr, d_binfo);
454
455 for (field = TYPE_FIELDS (BINFO_TYPE (d_binfo));
456 field; field = TREE_CHAIN (field))
457 /* Is this the base field created by build_base_field? */
458 if (TREE_CODE (field) == FIELD_DECL
459 && DECL_FIELD_IS_BASE (field)
460 && TREE_TYPE (field) == type)
461 {
462 /* We don't use build_class_member_access_expr here, as that
463 has unnecessary checks, and more importantly results in
464 recursive calls to dfs_walk_once. */
465 int type_quals = cp_type_quals (TREE_TYPE (expr));
466
467 expr = build3 (COMPONENT_REF,
468 cp_build_qualified_type (type, type_quals),
469 expr, field, NULL_TREE);
470 expr = fold_if_not_in_template (expr);
471
472 /* Mark the expression const or volatile, as appropriate.
473 Even though we've dealt with the type above, we still have
474 to mark the expression itself. */
475 if (type_quals & TYPE_QUAL_CONST)
476 TREE_READONLY (expr) = 1;
477 if (type_quals & TYPE_QUAL_VOLATILE)
478 TREE_THIS_VOLATILE (expr) = 1;
479
480 return expr;
481 }
482
483 /* Didn't find the base field?!? */
484 gcc_unreachable ();
485 }
486
487 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
488 type is a class type or a pointer to a class type. In the former
489 case, TYPE is also a class type; in the latter it is another
490 pointer type. If CHECK_ACCESS is true, an error message is emitted
491 if TYPE is inaccessible. If OBJECT has pointer type, the value is
492 assumed to be non-NULL. */
493
494 tree
convert_to_base(tree object,tree type,bool check_access,bool nonnull)495 convert_to_base (tree object, tree type, bool check_access, bool nonnull)
496 {
497 tree binfo;
498 tree object_type;
499
500 if (TYPE_PTR_P (TREE_TYPE (object)))
501 {
502 object_type = TREE_TYPE (TREE_TYPE (object));
503 type = TREE_TYPE (type);
504 }
505 else
506 object_type = TREE_TYPE (object);
507
508 binfo = lookup_base (object_type, type,
509 check_access ? ba_check : ba_unique,
510 NULL);
511 if (!binfo || binfo == error_mark_node)
512 return error_mark_node;
513
514 return build_base_path (PLUS_EXPR, object, binfo, nonnull);
515 }
516
517 /* EXPR is an expression with unqualified class type. BASE is a base
518 binfo of that class type. Returns EXPR, converted to the BASE
519 type. This function assumes that EXPR is the most derived class;
520 therefore virtual bases can be found at their static offsets. */
521
522 tree
convert_to_base_statically(tree expr,tree base)523 convert_to_base_statically (tree expr, tree base)
524 {
525 tree expr_type;
526
527 expr_type = TREE_TYPE (expr);
528 if (!SAME_BINFO_TYPE_P (BINFO_TYPE (base), expr_type))
529 {
530 tree pointer_type;
531
532 pointer_type = build_pointer_type (expr_type);
533 expr = build_unary_op (ADDR_EXPR, expr, /*noconvert=*/1);
534 if (!integer_zerop (BINFO_OFFSET (base)))
535 expr = build2 (PLUS_EXPR, pointer_type, expr,
536 build_nop (pointer_type, BINFO_OFFSET (base)));
537 expr = build_nop (build_pointer_type (BINFO_TYPE (base)), expr);
538 expr = build1 (INDIRECT_REF, BINFO_TYPE (base), expr);
539 }
540
541 return expr;
542 }
543
544
545 tree
build_vfield_ref(tree datum,tree type)546 build_vfield_ref (tree datum, tree type)
547 {
548 tree vfield, vcontext;
549
550 if (datum == error_mark_node)
551 return error_mark_node;
552
553 /* First, convert to the requested type. */
554 if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (datum), type))
555 datum = convert_to_base (datum, type, /*check_access=*/false,
556 /*nonnull=*/true);
557
558 /* Second, the requested type may not be the owner of its own vptr.
559 If not, convert to the base class that owns it. We cannot use
560 convert_to_base here, because VCONTEXT may appear more than once
561 in the inheritance hierarchy of TYPE, and thus direct conversion
562 between the types may be ambiguous. Following the path back up
563 one step at a time via primary bases avoids the problem. */
564 vfield = TYPE_VFIELD (type);
565 vcontext = DECL_CONTEXT (vfield);
566 while (!same_type_ignoring_top_level_qualifiers_p (vcontext, type))
567 {
568 datum = build_simple_base_path (datum, CLASSTYPE_PRIMARY_BINFO (type));
569 type = TREE_TYPE (datum);
570 }
571
572 return build3 (COMPONENT_REF, TREE_TYPE (vfield), datum, vfield, NULL_TREE);
573 }
574
575 /* Given an object INSTANCE, return an expression which yields the
576 vtable element corresponding to INDEX. There are many special
577 cases for INSTANCE which we take care of here, mainly to avoid
578 creating extra tree nodes when we don't have to. */
579
580 static tree
build_vtbl_ref_1(tree instance,tree idx)581 build_vtbl_ref_1 (tree instance, tree idx)
582 {
583 tree aref;
584 tree vtbl = NULL_TREE;
585
586 /* Try to figure out what a reference refers to, and
587 access its virtual function table directly. */
588
589 int cdtorp = 0;
590 tree fixed_type = fixed_type_or_null (instance, NULL, &cdtorp);
591
592 tree basetype = non_reference (TREE_TYPE (instance));
593
594 if (fixed_type && !cdtorp)
595 {
596 tree binfo = lookup_base (fixed_type, basetype,
597 ba_unique | ba_quiet, NULL);
598 if (binfo)
599 vtbl = unshare_expr (BINFO_VTABLE (binfo));
600 }
601
602 if (!vtbl)
603 vtbl = build_vfield_ref (instance, basetype);
604
605 assemble_external (vtbl);
606
607 aref = build_array_ref (vtbl, idx);
608 TREE_CONSTANT (aref) |= TREE_CONSTANT (vtbl) && TREE_CONSTANT (idx);
609 TREE_INVARIANT (aref) = TREE_CONSTANT (aref);
610
611 return aref;
612 }
613
614 tree
build_vtbl_ref(tree instance,tree idx)615 build_vtbl_ref (tree instance, tree idx)
616 {
617 tree aref = build_vtbl_ref_1 (instance, idx);
618
619 return aref;
620 }
621
622 /* Given a stable object pointer INSTANCE_PTR, return an expression which
623 yields a function pointer corresponding to vtable element INDEX. */
624
625 tree
build_vfn_ref(tree instance_ptr,tree idx)626 build_vfn_ref (tree instance_ptr, tree idx)
627 {
628 tree aref;
629
630 aref = build_vtbl_ref_1 (build_indirect_ref (instance_ptr, 0), idx);
631
632 /* When using function descriptors, the address of the
633 vtable entry is treated as a function pointer. */
634 if (TARGET_VTABLE_USES_DESCRIPTORS)
635 aref = build1 (NOP_EXPR, TREE_TYPE (aref),
636 build_unary_op (ADDR_EXPR, aref, /*noconvert=*/1));
637
638 /* Remember this as a method reference, for later devirtualization. */
639 aref = build3 (OBJ_TYPE_REF, TREE_TYPE (aref), aref, instance_ptr, idx);
640
641 return aref;
642 }
643
644 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
645 for the given TYPE. */
646
647 static tree
get_vtable_name(tree type)648 get_vtable_name (tree type)
649 {
650 return mangle_vtbl_for_type (type);
651 }
652
653 /* DECL is an entity associated with TYPE, like a virtual table or an
654 implicitly generated constructor. Determine whether or not DECL
655 should have external or internal linkage at the object file
656 level. This routine does not deal with COMDAT linkage and other
657 similar complexities; it simply sets TREE_PUBLIC if it possible for
658 entities in other translation units to contain copies of DECL, in
659 the abstract. */
660
661 void
set_linkage_according_to_type(tree type,tree decl)662 set_linkage_according_to_type (tree type, tree decl)
663 {
664 /* If TYPE involves a local class in a function with internal
665 linkage, then DECL should have internal linkage too. Other local
666 classes have no linkage -- but if their containing functions
667 have external linkage, it makes sense for DECL to have external
668 linkage too. That will allow template definitions to be merged,
669 for example. */
670 if (no_linkage_check (type, /*relaxed_p=*/true))
671 {
672 TREE_PUBLIC (decl) = 0;
673 DECL_INTERFACE_KNOWN (decl) = 1;
674 }
675 else
676 TREE_PUBLIC (decl) = 1;
677 }
678
679 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
680 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
681 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
682
683 static tree
build_vtable(tree class_type,tree name,tree vtable_type)684 build_vtable (tree class_type, tree name, tree vtable_type)
685 {
686 tree decl;
687
688 decl = build_lang_decl (VAR_DECL, name, vtable_type);
689 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
690 now to avoid confusion in mangle_decl. */
691 SET_DECL_ASSEMBLER_NAME (decl, name);
692 DECL_CONTEXT (decl) = class_type;
693 DECL_ARTIFICIAL (decl) = 1;
694 TREE_STATIC (decl) = 1;
695 TREE_READONLY (decl) = 1;
696 DECL_VIRTUAL_P (decl) = 1;
697 DECL_ALIGN (decl) = TARGET_VTABLE_ENTRY_ALIGN;
698 DECL_VTABLE_OR_VTT_P (decl) = 1;
699 /* At one time the vtable info was grabbed 2 words at a time. This
700 fails on sparc unless you have 8-byte alignment. (tiemann) */
701 DECL_ALIGN (decl) = MAX (TYPE_ALIGN (double_type_node),
702 DECL_ALIGN (decl));
703 set_linkage_according_to_type (class_type, decl);
704 /* The vtable has not been defined -- yet. */
705 DECL_EXTERNAL (decl) = 1;
706 DECL_NOT_REALLY_EXTERN (decl) = 1;
707
708 /* Mark the VAR_DECL node representing the vtable itself as a
709 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
710 is rather important that such things be ignored because any
711 effort to actually generate DWARF for them will run into
712 trouble when/if we encounter code like:
713
714 #pragma interface
715 struct S { virtual void member (); };
716
717 because the artificial declaration of the vtable itself (as
718 manufactured by the g++ front end) will say that the vtable is
719 a static member of `S' but only *after* the debug output for
720 the definition of `S' has already been output. This causes
721 grief because the DWARF entry for the definition of the vtable
722 will try to refer back to an earlier *declaration* of the
723 vtable as a static member of `S' and there won't be one. We
724 might be able to arrange to have the "vtable static member"
725 attached to the member list for `S' before the debug info for
726 `S' get written (which would solve the problem) but that would
727 require more intrusive changes to the g++ front end. */
728 DECL_IGNORED_P (decl) = 1;
729
730 return decl;
731 }
732
733 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
734 or even complete. If this does not exist, create it. If COMPLETE is
735 nonzero, then complete the definition of it -- that will render it
736 impossible to actually build the vtable, but is useful to get at those
737 which are known to exist in the runtime. */
738
739 tree
get_vtable_decl(tree type,int complete)740 get_vtable_decl (tree type, int complete)
741 {
742 tree decl;
743
744 if (CLASSTYPE_VTABLES (type))
745 return CLASSTYPE_VTABLES (type);
746
747 decl = build_vtable (type, get_vtable_name (type), vtbl_type_node);
748 CLASSTYPE_VTABLES (type) = decl;
749
750 if (complete)
751 {
752 DECL_EXTERNAL (decl) = 1;
753 finish_decl (decl, NULL_TREE, NULL_TREE);
754 }
755
756 return decl;
757 }
758
759 /* Build the primary virtual function table for TYPE. If BINFO is
760 non-NULL, build the vtable starting with the initial approximation
761 that it is the same as the one which is the head of the association
762 list. Returns a nonzero value if a new vtable is actually
763 created. */
764
765 static int
build_primary_vtable(tree binfo,tree type)766 build_primary_vtable (tree binfo, tree type)
767 {
768 tree decl;
769 tree virtuals;
770
771 decl = get_vtable_decl (type, /*complete=*/0);
772
773 if (binfo)
774 {
775 if (BINFO_NEW_VTABLE_MARKED (binfo))
776 /* We have already created a vtable for this base, so there's
777 no need to do it again. */
778 return 0;
779
780 virtuals = copy_list (BINFO_VIRTUALS (binfo));
781 TREE_TYPE (decl) = TREE_TYPE (get_vtbl_decl_for_binfo (binfo));
782 DECL_SIZE (decl) = TYPE_SIZE (TREE_TYPE (decl));
783 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (TREE_TYPE (decl));
784 }
785 else
786 {
787 gcc_assert (TREE_TYPE (decl) == vtbl_type_node);
788 virtuals = NULL_TREE;
789 }
790
791 #ifdef GATHER_STATISTICS
792 n_vtables += 1;
793 n_vtable_elems += list_length (virtuals);
794 #endif
795
796 /* Initialize the association list for this type, based
797 on our first approximation. */
798 BINFO_VTABLE (TYPE_BINFO (type)) = decl;
799 BINFO_VIRTUALS (TYPE_BINFO (type)) = virtuals;
800 SET_BINFO_NEW_VTABLE_MARKED (TYPE_BINFO (type));
801 return 1;
802 }
803
804 /* Give BINFO a new virtual function table which is initialized
805 with a skeleton-copy of its original initialization. The only
806 entry that changes is the `delta' entry, so we can really
807 share a lot of structure.
808
809 FOR_TYPE is the most derived type which caused this table to
810 be needed.
811
812 Returns nonzero if we haven't met BINFO before.
813
814 The order in which vtables are built (by calling this function) for
815 an object must remain the same, otherwise a binary incompatibility
816 can result. */
817
818 static int
build_secondary_vtable(tree binfo)819 build_secondary_vtable (tree binfo)
820 {
821 if (BINFO_NEW_VTABLE_MARKED (binfo))
822 /* We already created a vtable for this base. There's no need to
823 do it again. */
824 return 0;
825
826 /* Remember that we've created a vtable for this BINFO, so that we
827 don't try to do so again. */
828 SET_BINFO_NEW_VTABLE_MARKED (binfo);
829
830 /* Make fresh virtual list, so we can smash it later. */
831 BINFO_VIRTUALS (binfo) = copy_list (BINFO_VIRTUALS (binfo));
832
833 /* Secondary vtables are laid out as part of the same structure as
834 the primary vtable. */
835 BINFO_VTABLE (binfo) = NULL_TREE;
836 return 1;
837 }
838
839 /* Create a new vtable for BINFO which is the hierarchy dominated by
840 T. Return nonzero if we actually created a new vtable. */
841
842 static int
make_new_vtable(tree t,tree binfo)843 make_new_vtable (tree t, tree binfo)
844 {
845 if (binfo == TYPE_BINFO (t))
846 /* In this case, it is *type*'s vtable we are modifying. We start
847 with the approximation that its vtable is that of the
848 immediate base class. */
849 return build_primary_vtable (binfo, t);
850 else
851 /* This is our very own copy of `basetype' to play with. Later,
852 we will fill in all the virtual functions that override the
853 virtual functions in these base classes which are not defined
854 by the current type. */
855 return build_secondary_vtable (binfo);
856 }
857
858 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
859 (which is in the hierarchy dominated by T) list FNDECL as its
860 BV_FN. DELTA is the required constant adjustment from the `this'
861 pointer where the vtable entry appears to the `this' required when
862 the function is actually called. */
863
864 static void
modify_vtable_entry(tree t,tree binfo,tree fndecl,tree delta,tree * virtuals)865 modify_vtable_entry (tree t,
866 tree binfo,
867 tree fndecl,
868 tree delta,
869 tree *virtuals)
870 {
871 tree v;
872
873 v = *virtuals;
874
875 if (fndecl != BV_FN (v)
876 || !tree_int_cst_equal (delta, BV_DELTA (v)))
877 {
878 /* We need a new vtable for BINFO. */
879 if (make_new_vtable (t, binfo))
880 {
881 /* If we really did make a new vtable, we also made a copy
882 of the BINFO_VIRTUALS list. Now, we have to find the
883 corresponding entry in that list. */
884 *virtuals = BINFO_VIRTUALS (binfo);
885 while (BV_FN (*virtuals) != BV_FN (v))
886 *virtuals = TREE_CHAIN (*virtuals);
887 v = *virtuals;
888 }
889
890 BV_DELTA (v) = delta;
891 BV_VCALL_INDEX (v) = NULL_TREE;
892 BV_FN (v) = fndecl;
893 }
894 }
895
896
897 /* Add method METHOD to class TYPE. If USING_DECL is non-null, it is
898 the USING_DECL naming METHOD. Returns true if the method could be
899 added to the method vec. */
900
901 bool
add_method(tree type,tree method,tree using_decl)902 add_method (tree type, tree method, tree using_decl)
903 {
904 unsigned slot;
905 tree overload;
906 bool template_conv_p = false;
907 bool conv_p;
908 VEC(tree,gc) *method_vec;
909 bool complete_p;
910 bool insert_p = false;
911 tree current_fns;
912
913 if (method == error_mark_node)
914 return false;
915
916 complete_p = COMPLETE_TYPE_P (type);
917 conv_p = DECL_CONV_FN_P (method);
918 if (conv_p)
919 template_conv_p = (TREE_CODE (method) == TEMPLATE_DECL
920 && DECL_TEMPLATE_CONV_FN_P (method));
921
922 method_vec = CLASSTYPE_METHOD_VEC (type);
923 if (!method_vec)
924 {
925 /* Make a new method vector. We start with 8 entries. We must
926 allocate at least two (for constructors and destructors), and
927 we're going to end up with an assignment operator at some
928 point as well. */
929 method_vec = VEC_alloc (tree, gc, 8);
930 /* Create slots for constructors and destructors. */
931 VEC_quick_push (tree, method_vec, NULL_TREE);
932 VEC_quick_push (tree, method_vec, NULL_TREE);
933 CLASSTYPE_METHOD_VEC (type) = method_vec;
934 }
935
936 /* Maintain TYPE_HAS_CONSTRUCTOR, etc. */
937 grok_special_member_properties (method);
938
939 /* Constructors and destructors go in special slots. */
940 if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (method))
941 slot = CLASSTYPE_CONSTRUCTOR_SLOT;
942 else if (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (method))
943 {
944 slot = CLASSTYPE_DESTRUCTOR_SLOT;
945
946 if (TYPE_FOR_JAVA (type))
947 {
948 if (!DECL_ARTIFICIAL (method))
949 error ("Java class %qT cannot have a destructor", type);
950 else if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
951 error ("Java class %qT cannot have an implicit non-trivial "
952 "destructor",
953 type);
954 }
955 }
956 else
957 {
958 tree m;
959
960 insert_p = true;
961 /* See if we already have an entry with this name. */
962 for (slot = CLASSTYPE_FIRST_CONVERSION_SLOT;
963 VEC_iterate (tree, method_vec, slot, m);
964 ++slot)
965 {
966 m = OVL_CURRENT (m);
967 if (template_conv_p)
968 {
969 if (TREE_CODE (m) == TEMPLATE_DECL
970 && DECL_TEMPLATE_CONV_FN_P (m))
971 insert_p = false;
972 break;
973 }
974 if (conv_p && !DECL_CONV_FN_P (m))
975 break;
976 if (DECL_NAME (m) == DECL_NAME (method))
977 {
978 insert_p = false;
979 break;
980 }
981 if (complete_p
982 && !DECL_CONV_FN_P (m)
983 && DECL_NAME (m) > DECL_NAME (method))
984 break;
985 }
986 }
987 current_fns = insert_p ? NULL_TREE : VEC_index (tree, method_vec, slot);
988
989 if (processing_template_decl)
990 /* TYPE is a template class. Don't issue any errors now; wait
991 until instantiation time to complain. */
992 ;
993 else
994 {
995 tree fns;
996
997 /* Check to see if we've already got this method. */
998 for (fns = current_fns; fns; fns = OVL_NEXT (fns))
999 {
1000 tree fn = OVL_CURRENT (fns);
1001 tree fn_type;
1002 tree method_type;
1003 tree parms1;
1004 tree parms2;
1005
1006 if (TREE_CODE (fn) != TREE_CODE (method))
1007 continue;
1008
1009 /* [over.load] Member function declarations with the
1010 same name and the same parameter types cannot be
1011 overloaded if any of them is a static member
1012 function declaration.
1013
1014 [namespace.udecl] When a using-declaration brings names
1015 from a base class into a derived class scope, member
1016 functions in the derived class override and/or hide member
1017 functions with the same name and parameter types in a base
1018 class (rather than conflicting). */
1019 fn_type = TREE_TYPE (fn);
1020 method_type = TREE_TYPE (method);
1021 parms1 = TYPE_ARG_TYPES (fn_type);
1022 parms2 = TYPE_ARG_TYPES (method_type);
1023
1024 /* Compare the quals on the 'this' parm. Don't compare
1025 the whole types, as used functions are treated as
1026 coming from the using class in overload resolution. */
1027 if (! DECL_STATIC_FUNCTION_P (fn)
1028 && ! DECL_STATIC_FUNCTION_P (method)
1029 && (TYPE_QUALS (TREE_TYPE (TREE_VALUE (parms1)))
1030 != TYPE_QUALS (TREE_TYPE (TREE_VALUE (parms2)))))
1031 continue;
1032
1033 /* For templates, the return type and template parameters
1034 must be identical. */
1035 if (TREE_CODE (fn) == TEMPLATE_DECL
1036 && (!same_type_p (TREE_TYPE (fn_type),
1037 TREE_TYPE (method_type))
1038 || !comp_template_parms (DECL_TEMPLATE_PARMS (fn),
1039 DECL_TEMPLATE_PARMS (method))))
1040 continue;
1041
1042 if (! DECL_STATIC_FUNCTION_P (fn))
1043 parms1 = TREE_CHAIN (parms1);
1044 if (! DECL_STATIC_FUNCTION_P (method))
1045 parms2 = TREE_CHAIN (parms2);
1046
1047 if (compparms (parms1, parms2)
1048 && (!DECL_CONV_FN_P (fn)
1049 || same_type_p (TREE_TYPE (fn_type),
1050 TREE_TYPE (method_type))))
1051 {
1052 if (using_decl)
1053 {
1054 if (DECL_CONTEXT (fn) == type)
1055 /* Defer to the local function. */
1056 return false;
1057 if (DECL_CONTEXT (fn) == DECL_CONTEXT (method))
1058 error ("repeated using declaration %q+D", using_decl);
1059 else
1060 error ("using declaration %q+D conflicts with a previous using declaration",
1061 using_decl);
1062 }
1063 else
1064 {
1065 error ("%q+#D cannot be overloaded", method);
1066 error ("with %q+#D", fn);
1067 }
1068
1069 /* We don't call duplicate_decls here to merge the
1070 declarations because that will confuse things if the
1071 methods have inline definitions. In particular, we
1072 will crash while processing the definitions. */
1073 return false;
1074 }
1075 }
1076 }
1077
1078 /* A class should never have more than one destructor. */
1079 if (current_fns && DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (method))
1080 return false;
1081
1082 /* Add the new binding. */
1083 overload = build_overload (method, current_fns);
1084
1085 if (conv_p)
1086 TYPE_HAS_CONVERSION (type) = 1;
1087 else if (slot >= CLASSTYPE_FIRST_CONVERSION_SLOT && !complete_p)
1088 push_class_level_binding (DECL_NAME (method), overload);
1089
1090 if (insert_p)
1091 {
1092 bool reallocated;
1093
1094 /* We only expect to add few methods in the COMPLETE_P case, so
1095 just make room for one more method in that case. */
1096 if (complete_p)
1097 reallocated = VEC_reserve_exact (tree, gc, method_vec, 1);
1098 else
1099 reallocated = VEC_reserve (tree, gc, method_vec, 1);
1100 if (reallocated)
1101 CLASSTYPE_METHOD_VEC (type) = method_vec;
1102 if (slot == VEC_length (tree, method_vec))
1103 VEC_quick_push (tree, method_vec, overload);
1104 else
1105 VEC_quick_insert (tree, method_vec, slot, overload);
1106 }
1107 else
1108 /* Replace the current slot. */
1109 VEC_replace (tree, method_vec, slot, overload);
1110 return true;
1111 }
1112
1113 /* Subroutines of finish_struct. */
1114
1115 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1116 legit, otherwise return 0. */
1117
1118 static int
alter_access(tree t,tree fdecl,tree access)1119 alter_access (tree t, tree fdecl, tree access)
1120 {
1121 tree elem;
1122
1123 if (!DECL_LANG_SPECIFIC (fdecl))
1124 retrofit_lang_decl (fdecl);
1125
1126 gcc_assert (!DECL_DISCRIMINATOR_P (fdecl));
1127
1128 elem = purpose_member (t, DECL_ACCESS (fdecl));
1129 if (elem)
1130 {
1131 if (TREE_VALUE (elem) != access)
1132 {
1133 if (TREE_CODE (TREE_TYPE (fdecl)) == FUNCTION_DECL)
1134 error ("conflicting access specifications for method"
1135 " %q+D, ignored", TREE_TYPE (fdecl));
1136 else
1137 error ("conflicting access specifications for field %qE, ignored",
1138 DECL_NAME (fdecl));
1139 }
1140 else
1141 {
1142 /* They're changing the access to the same thing they changed
1143 it to before. That's OK. */
1144 ;
1145 }
1146 }
1147 else
1148 {
1149 perform_or_defer_access_check (TYPE_BINFO (t), fdecl, fdecl);
1150 DECL_ACCESS (fdecl) = tree_cons (t, access, DECL_ACCESS (fdecl));
1151 return 1;
1152 }
1153 return 0;
1154 }
1155
1156 /* Process the USING_DECL, which is a member of T. */
1157
1158 static void
handle_using_decl(tree using_decl,tree t)1159 handle_using_decl (tree using_decl, tree t)
1160 {
1161 tree decl = USING_DECL_DECLS (using_decl);
1162 tree name = DECL_NAME (using_decl);
1163 tree access
1164 = TREE_PRIVATE (using_decl) ? access_private_node
1165 : TREE_PROTECTED (using_decl) ? access_protected_node
1166 : access_public_node;
1167 tree flist = NULL_TREE;
1168 tree old_value;
1169
1170 gcc_assert (!processing_template_decl && decl);
1171
1172 old_value = lookup_member (t, name, /*protect=*/0, /*want_type=*/false);
1173 if (old_value)
1174 {
1175 if (is_overloaded_fn (old_value))
1176 old_value = OVL_CURRENT (old_value);
1177
1178 if (DECL_P (old_value) && DECL_CONTEXT (old_value) == t)
1179 /* OK */;
1180 else
1181 old_value = NULL_TREE;
1182 }
1183
1184 cp_emit_debug_info_for_using (decl, USING_DECL_SCOPE (using_decl));
1185
1186 if (is_overloaded_fn (decl))
1187 flist = decl;
1188
1189 if (! old_value)
1190 ;
1191 else if (is_overloaded_fn (old_value))
1192 {
1193 if (flist)
1194 /* It's OK to use functions from a base when there are functions with
1195 the same name already present in the current class. */;
1196 else
1197 {
1198 error ("%q+D invalid in %q#T", using_decl, t);
1199 error (" because of local method %q+#D with same name",
1200 OVL_CURRENT (old_value));
1201 return;
1202 }
1203 }
1204 else if (!DECL_ARTIFICIAL (old_value))
1205 {
1206 error ("%q+D invalid in %q#T", using_decl, t);
1207 error (" because of local member %q+#D with same name", old_value);
1208 return;
1209 }
1210
1211 /* Make type T see field decl FDECL with access ACCESS. */
1212 if (flist)
1213 for (; flist; flist = OVL_NEXT (flist))
1214 {
1215 add_method (t, OVL_CURRENT (flist), using_decl);
1216 alter_access (t, OVL_CURRENT (flist), access);
1217 }
1218 else
1219 alter_access (t, decl, access);
1220 }
1221
1222 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1223 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1224 properties of the bases. */
1225
1226 static void
check_bases(tree t,int * cant_have_const_ctor_p,int * no_const_asn_ref_p)1227 check_bases (tree t,
1228 int* cant_have_const_ctor_p,
1229 int* no_const_asn_ref_p)
1230 {
1231 int i;
1232 int seen_non_virtual_nearly_empty_base_p;
1233 tree base_binfo;
1234 tree binfo;
1235
1236 seen_non_virtual_nearly_empty_base_p = 0;
1237
1238 for (binfo = TYPE_BINFO (t), i = 0;
1239 BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
1240 {
1241 tree basetype = TREE_TYPE (base_binfo);
1242
1243 gcc_assert (COMPLETE_TYPE_P (basetype));
1244
1245 /* Effective C++ rule 14. We only need to check TYPE_POLYMORPHIC_P
1246 here because the case of virtual functions but non-virtual
1247 dtor is handled in finish_struct_1. */
1248 if (!TYPE_POLYMORPHIC_P (basetype))
1249 warning (OPT_Weffc__,
1250 "base class %q#T has a non-virtual destructor", basetype);
1251
1252 /* If the base class doesn't have copy constructors or
1253 assignment operators that take const references, then the
1254 derived class cannot have such a member automatically
1255 generated. */
1256 if (! TYPE_HAS_CONST_INIT_REF (basetype))
1257 *cant_have_const_ctor_p = 1;
1258 if (TYPE_HAS_ASSIGN_REF (basetype)
1259 && !TYPE_HAS_CONST_ASSIGN_REF (basetype))
1260 *no_const_asn_ref_p = 1;
1261
1262 if (BINFO_VIRTUAL_P (base_binfo))
1263 /* A virtual base does not effect nearly emptiness. */
1264 ;
1265 else if (CLASSTYPE_NEARLY_EMPTY_P (basetype))
1266 {
1267 if (seen_non_virtual_nearly_empty_base_p)
1268 /* And if there is more than one nearly empty base, then the
1269 derived class is not nearly empty either. */
1270 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
1271 else
1272 /* Remember we've seen one. */
1273 seen_non_virtual_nearly_empty_base_p = 1;
1274 }
1275 else if (!is_empty_class (basetype))
1276 /* If the base class is not empty or nearly empty, then this
1277 class cannot be nearly empty. */
1278 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
1279
1280 /* A lot of properties from the bases also apply to the derived
1281 class. */
1282 TYPE_NEEDS_CONSTRUCTING (t) |= TYPE_NEEDS_CONSTRUCTING (basetype);
1283 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
1284 |= TYPE_HAS_NONTRIVIAL_DESTRUCTOR (basetype);
1285 /* APPLE LOCAL begin omit calls to empty destructors 5559195 */
1286 if (CLASSTYPE_HAS_NONTRIVIAL_DESTRUCTOR_BODY (basetype)
1287 || CLASSTYPE_DESTRUCTOR_NONTRIVIAL_BECAUSE_OF_BASE (basetype))
1288 CLASSTYPE_DESTRUCTOR_NONTRIVIAL_BECAUSE_OF_BASE (t) = 1;
1289 /* APPLE LOCAL end omit calls to empty destructors 5559195 */
1290
1291 TYPE_HAS_COMPLEX_ASSIGN_REF (t)
1292 |= TYPE_HAS_COMPLEX_ASSIGN_REF (basetype);
1293 TYPE_HAS_COMPLEX_INIT_REF (t) |= TYPE_HAS_COMPLEX_INIT_REF (basetype);
1294 TYPE_POLYMORPHIC_P (t) |= TYPE_POLYMORPHIC_P (basetype);
1295 CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t)
1296 |= CLASSTYPE_CONTAINS_EMPTY_CLASS_P (basetype);
1297 }
1298 }
1299
1300 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1301 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1302 that have had a nearly-empty virtual primary base stolen by some
1303 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1304 T. */
1305
1306 static void
determine_primary_bases(tree t)1307 determine_primary_bases (tree t)
1308 {
1309 unsigned i;
1310 tree primary = NULL_TREE;
1311 tree type_binfo = TYPE_BINFO (t);
1312 tree base_binfo;
1313
1314 /* Determine the primary bases of our bases. */
1315 for (base_binfo = TREE_CHAIN (type_binfo); base_binfo;
1316 base_binfo = TREE_CHAIN (base_binfo))
1317 {
1318 tree primary = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (base_binfo));
1319
1320 /* See if we're the non-virtual primary of our inheritance
1321 chain. */
1322 if (!BINFO_VIRTUAL_P (base_binfo))
1323 {
1324 tree parent = BINFO_INHERITANCE_CHAIN (base_binfo);
1325 tree parent_primary = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (parent));
1326
1327 if (parent_primary
1328 && SAME_BINFO_TYPE_P (BINFO_TYPE (base_binfo),
1329 BINFO_TYPE (parent_primary)))
1330 /* We are the primary binfo. */
1331 BINFO_PRIMARY_P (base_binfo) = 1;
1332 }
1333 /* Determine if we have a virtual primary base, and mark it so.
1334 */
1335 if (primary && BINFO_VIRTUAL_P (primary))
1336 {
1337 tree this_primary = copied_binfo (primary, base_binfo);
1338
1339 if (BINFO_PRIMARY_P (this_primary))
1340 /* Someone already claimed this base. */
1341 BINFO_LOST_PRIMARY_P (base_binfo) = 1;
1342 else
1343 {
1344 tree delta;
1345
1346 BINFO_PRIMARY_P (this_primary) = 1;
1347 BINFO_INHERITANCE_CHAIN (this_primary) = base_binfo;
1348
1349 /* A virtual binfo might have been copied from within
1350 another hierarchy. As we're about to use it as a
1351 primary base, make sure the offsets match. */
1352 delta = size_diffop (convert (ssizetype,
1353 BINFO_OFFSET (base_binfo)),
1354 convert (ssizetype,
1355 BINFO_OFFSET (this_primary)));
1356
1357 propagate_binfo_offsets (this_primary, delta);
1358 }
1359 }
1360 }
1361
1362 /* First look for a dynamic direct non-virtual base. */
1363 for (i = 0; BINFO_BASE_ITERATE (type_binfo, i, base_binfo); i++)
1364 {
1365 tree basetype = BINFO_TYPE (base_binfo);
1366
1367 if (TYPE_CONTAINS_VPTR_P (basetype) && !BINFO_VIRTUAL_P (base_binfo))
1368 {
1369 primary = base_binfo;
1370 goto found;
1371 }
1372 }
1373
1374 /* A "nearly-empty" virtual base class can be the primary base
1375 class, if no non-virtual polymorphic base can be found. Look for
1376 a nearly-empty virtual dynamic base that is not already a primary
1377 base of something in the hierarchy. If there is no such base,
1378 just pick the first nearly-empty virtual base. */
1379
1380 for (base_binfo = TREE_CHAIN (type_binfo); base_binfo;
1381 base_binfo = TREE_CHAIN (base_binfo))
1382 if (BINFO_VIRTUAL_P (base_binfo)
1383 && CLASSTYPE_NEARLY_EMPTY_P (BINFO_TYPE (base_binfo)))
1384 {
1385 if (!BINFO_PRIMARY_P (base_binfo))
1386 {
1387 /* Found one that is not primary. */
1388 primary = base_binfo;
1389 goto found;
1390 }
1391 else if (!primary)
1392 /* Remember the first candidate. */
1393 primary = base_binfo;
1394 }
1395
1396 found:
1397 /* If we've got a primary base, use it. */
1398 if (primary)
1399 {
1400 tree basetype = BINFO_TYPE (primary);
1401
1402 CLASSTYPE_PRIMARY_BINFO (t) = primary;
1403 if (BINFO_PRIMARY_P (primary))
1404 /* We are stealing a primary base. */
1405 BINFO_LOST_PRIMARY_P (BINFO_INHERITANCE_CHAIN (primary)) = 1;
1406 BINFO_PRIMARY_P (primary) = 1;
1407 if (BINFO_VIRTUAL_P (primary))
1408 {
1409 tree delta;
1410
1411 BINFO_INHERITANCE_CHAIN (primary) = type_binfo;
1412 /* A virtual binfo might have been copied from within
1413 another hierarchy. As we're about to use it as a primary
1414 base, make sure the offsets match. */
1415 delta = size_diffop (ssize_int (0),
1416 convert (ssizetype, BINFO_OFFSET (primary)));
1417
1418 propagate_binfo_offsets (primary, delta);
1419 }
1420
1421 primary = TYPE_BINFO (basetype);
1422
1423 TYPE_VFIELD (t) = TYPE_VFIELD (basetype);
1424 BINFO_VTABLE (type_binfo) = BINFO_VTABLE (primary);
1425 BINFO_VIRTUALS (type_binfo) = BINFO_VIRTUALS (primary);
1426 }
1427 }
1428
1429 /* Set memoizing fields and bits of T (and its variants) for later
1430 use. */
1431
1432 static void
finish_struct_bits(tree t)1433 finish_struct_bits (tree t)
1434 {
1435 tree variants;
1436
1437 /* Fix up variants (if any). */
1438 for (variants = TYPE_NEXT_VARIANT (t);
1439 variants;
1440 variants = TYPE_NEXT_VARIANT (variants))
1441 {
1442 /* These fields are in the _TYPE part of the node, not in
1443 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1444 TYPE_HAS_CONSTRUCTOR (variants) = TYPE_HAS_CONSTRUCTOR (t);
1445 TYPE_NEEDS_CONSTRUCTING (variants) = TYPE_NEEDS_CONSTRUCTING (t);
1446 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (variants)
1447 = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t);
1448
1449 /* APPLE LOCAL begin omit calls to empty destructors 5559195 */
1450 CLASSTYPE_HAS_NONTRIVIAL_DESTRUCTOR_BODY (variants) =
1451 CLASSTYPE_HAS_NONTRIVIAL_DESTRUCTOR_BODY (t);
1452 CLASSTYPE_DESTRUCTOR_NONTRIVIAL_BECAUSE_OF_BASE (variants) =
1453 CLASSTYPE_DESTRUCTOR_NONTRIVIAL_BECAUSE_OF_BASE (t);
1454 /* APPLE LOCAL end omit calls to empty destructors 5559195 */
1455
1456 TYPE_POLYMORPHIC_P (variants) = TYPE_POLYMORPHIC_P (t);
1457
1458 TYPE_BINFO (variants) = TYPE_BINFO (t);
1459
1460 /* Copy whatever these are holding today. */
1461 TYPE_VFIELD (variants) = TYPE_VFIELD (t);
1462 TYPE_METHODS (variants) = TYPE_METHODS (t);
1463 TYPE_FIELDS (variants) = TYPE_FIELDS (t);
1464 }
1465
1466 if (BINFO_N_BASE_BINFOS (TYPE_BINFO (t)) && TYPE_POLYMORPHIC_P (t))
1467 /* For a class w/o baseclasses, 'finish_struct' has set
1468 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
1469 Similarly for a class whose base classes do not have vtables.
1470 When neither of these is true, we might have removed abstract
1471 virtuals (by providing a definition), added some (by declaring
1472 new ones), or redeclared ones from a base class. We need to
1473 recalculate what's really an abstract virtual at this point (by
1474 looking in the vtables). */
1475 get_pure_virtuals (t);
1476
1477 /* If this type has a copy constructor or a destructor, force its
1478 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
1479 nonzero. This will cause it to be passed by invisible reference
1480 and prevent it from being returned in a register. */
1481 if (! TYPE_HAS_TRIVIAL_INIT_REF (t) || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t))
1482 {
1483 tree variants;
1484 DECL_MODE (TYPE_MAIN_DECL (t)) = BLKmode;
1485 for (variants = t; variants; variants = TYPE_NEXT_VARIANT (variants))
1486 {
1487 TYPE_MODE (variants) = BLKmode;
1488 TREE_ADDRESSABLE (variants) = 1;
1489 }
1490 }
1491 }
1492
1493 /* Issue warnings about T having private constructors, but no friends,
1494 and so forth.
1495
1496 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
1497 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
1498 non-private static member functions. */
1499
1500 static void
maybe_warn_about_overly_private_class(tree t)1501 maybe_warn_about_overly_private_class (tree t)
1502 {
1503 int has_member_fn = 0;
1504 int has_nonprivate_method = 0;
1505 tree fn;
1506
1507 if (!warn_ctor_dtor_privacy
1508 /* If the class has friends, those entities might create and
1509 access instances, so we should not warn. */
1510 || (CLASSTYPE_FRIEND_CLASSES (t)
1511 || DECL_FRIENDLIST (TYPE_MAIN_DECL (t)))
1512 /* We will have warned when the template was declared; there's
1513 no need to warn on every instantiation. */
1514 || CLASSTYPE_TEMPLATE_INSTANTIATION (t))
1515 /* There's no reason to even consider warning about this
1516 class. */
1517 return;
1518
1519 /* We only issue one warning, if more than one applies, because
1520 otherwise, on code like:
1521
1522 class A {
1523 // Oops - forgot `public:'
1524 A();
1525 A(const A&);
1526 ~A();
1527 };
1528
1529 we warn several times about essentially the same problem. */
1530
1531 /* Check to see if all (non-constructor, non-destructor) member
1532 functions are private. (Since there are no friends or
1533 non-private statics, we can't ever call any of the private member
1534 functions.) */
1535 for (fn = TYPE_METHODS (t); fn; fn = TREE_CHAIN (fn))
1536 /* We're not interested in compiler-generated methods; they don't
1537 provide any way to call private members. */
1538 if (!DECL_ARTIFICIAL (fn))
1539 {
1540 if (!TREE_PRIVATE (fn))
1541 {
1542 if (DECL_STATIC_FUNCTION_P (fn))
1543 /* A non-private static member function is just like a
1544 friend; it can create and invoke private member
1545 functions, and be accessed without a class
1546 instance. */
1547 return;
1548
1549 has_nonprivate_method = 1;
1550 /* Keep searching for a static member function. */
1551 }
1552 else if (!DECL_CONSTRUCTOR_P (fn) && !DECL_DESTRUCTOR_P (fn))
1553 has_member_fn = 1;
1554 }
1555
1556 if (!has_nonprivate_method && has_member_fn)
1557 {
1558 /* There are no non-private methods, and there's at least one
1559 private member function that isn't a constructor or
1560 destructor. (If all the private members are
1561 constructors/destructors we want to use the code below that
1562 issues error messages specifically referring to
1563 constructors/destructors.) */
1564 unsigned i;
1565 tree binfo = TYPE_BINFO (t);
1566
1567 for (i = 0; i != BINFO_N_BASE_BINFOS (binfo); i++)
1568 if (BINFO_BASE_ACCESS (binfo, i) != access_private_node)
1569 {
1570 has_nonprivate_method = 1;
1571 break;
1572 }
1573 if (!has_nonprivate_method)
1574 {
1575 warning (OPT_Wctor_dtor_privacy,
1576 "all member functions in class %qT are private", t);
1577 return;
1578 }
1579 }
1580
1581 /* Even if some of the member functions are non-private, the class
1582 won't be useful for much if all the constructors or destructors
1583 are private: such an object can never be created or destroyed. */
1584 fn = CLASSTYPE_DESTRUCTORS (t);
1585 if (fn && TREE_PRIVATE (fn))
1586 {
1587 warning (OPT_Wctor_dtor_privacy,
1588 "%q#T only defines a private destructor and has no friends",
1589 t);
1590 return;
1591 }
1592
1593 if (TYPE_HAS_CONSTRUCTOR (t)
1594 /* Implicitly generated constructors are always public. */
1595 && (!CLASSTYPE_LAZY_DEFAULT_CTOR (t)
1596 || !CLASSTYPE_LAZY_COPY_CTOR (t)))
1597 {
1598 int nonprivate_ctor = 0;
1599
1600 /* If a non-template class does not define a copy
1601 constructor, one is defined for it, enabling it to avoid
1602 this warning. For a template class, this does not
1603 happen, and so we would normally get a warning on:
1604
1605 template <class T> class C { private: C(); };
1606
1607 To avoid this asymmetry, we check TYPE_HAS_INIT_REF. All
1608 complete non-template or fully instantiated classes have this
1609 flag set. */
1610 if (!TYPE_HAS_INIT_REF (t))
1611 nonprivate_ctor = 1;
1612 else
1613 for (fn = CLASSTYPE_CONSTRUCTORS (t); fn; fn = OVL_NEXT (fn))
1614 {
1615 tree ctor = OVL_CURRENT (fn);
1616 /* Ideally, we wouldn't count copy constructors (or, in
1617 fact, any constructor that takes an argument of the
1618 class type as a parameter) because such things cannot
1619 be used to construct an instance of the class unless
1620 you already have one. But, for now at least, we're
1621 more generous. */
1622 if (! TREE_PRIVATE (ctor))
1623 {
1624 nonprivate_ctor = 1;
1625 break;
1626 }
1627 }
1628
1629 if (nonprivate_ctor == 0)
1630 {
1631 warning (OPT_Wctor_dtor_privacy,
1632 "%q#T only defines private constructors and has no friends",
1633 t);
1634 return;
1635 }
1636 }
1637 }
1638
1639 static struct {
1640 gt_pointer_operator new_value;
1641 void *cookie;
1642 } resort_data;
1643
1644 /* Comparison function to compare two TYPE_METHOD_VEC entries by name. */
1645
1646 static int
method_name_cmp(const void * m1_p,const void * m2_p)1647 method_name_cmp (const void* m1_p, const void* m2_p)
1648 {
1649 const tree *const m1 = (const tree *) m1_p;
1650 const tree *const m2 = (const tree *) m2_p;
1651
1652 if (*m1 == NULL_TREE && *m2 == NULL_TREE)
1653 return 0;
1654 if (*m1 == NULL_TREE)
1655 return -1;
1656 if (*m2 == NULL_TREE)
1657 return 1;
1658 if (DECL_NAME (OVL_CURRENT (*m1)) < DECL_NAME (OVL_CURRENT (*m2)))
1659 return -1;
1660 return 1;
1661 }
1662
1663 /* This routine compares two fields like method_name_cmp but using the
1664 pointer operator in resort_field_decl_data. */
1665
1666 static int
resort_method_name_cmp(const void * m1_p,const void * m2_p)1667 resort_method_name_cmp (const void* m1_p, const void* m2_p)
1668 {
1669 const tree *const m1 = (const tree *) m1_p;
1670 const tree *const m2 = (const tree *) m2_p;
1671 if (*m1 == NULL_TREE && *m2 == NULL_TREE)
1672 return 0;
1673 if (*m1 == NULL_TREE)
1674 return -1;
1675 if (*m2 == NULL_TREE)
1676 return 1;
1677 {
1678 tree d1 = DECL_NAME (OVL_CURRENT (*m1));
1679 tree d2 = DECL_NAME (OVL_CURRENT (*m2));
1680 resort_data.new_value (&d1, resort_data.cookie);
1681 resort_data.new_value (&d2, resort_data.cookie);
1682 if (d1 < d2)
1683 return -1;
1684 }
1685 return 1;
1686 }
1687
1688 /* Resort TYPE_METHOD_VEC because pointers have been reordered. */
1689
1690 void
resort_type_method_vec(void * obj,void * orig_obj ATTRIBUTE_UNUSED,gt_pointer_operator new_value,void * cookie)1691 resort_type_method_vec (void* obj,
1692 void* orig_obj ATTRIBUTE_UNUSED ,
1693 gt_pointer_operator new_value,
1694 void* cookie)
1695 {
1696 VEC(tree,gc) *method_vec = (VEC(tree,gc) *) obj;
1697 int len = VEC_length (tree, method_vec);
1698 size_t slot;
1699 tree fn;
1700
1701 /* The type conversion ops have to live at the front of the vec, so we
1702 can't sort them. */
1703 for (slot = CLASSTYPE_FIRST_CONVERSION_SLOT;
1704 VEC_iterate (tree, method_vec, slot, fn);
1705 ++slot)
1706 if (!DECL_CONV_FN_P (OVL_CURRENT (fn)))
1707 break;
1708
1709 if (len - slot > 1)
1710 {
1711 resort_data.new_value = new_value;
1712 resort_data.cookie = cookie;
1713 qsort (VEC_address (tree, method_vec) + slot, len - slot, sizeof (tree),
1714 resort_method_name_cmp);
1715 }
1716 }
1717
1718 /* Warn about duplicate methods in fn_fields.
1719
1720 Sort methods that are not special (i.e., constructors, destructors,
1721 and type conversion operators) so that we can find them faster in
1722 search. */
1723
1724 static void
finish_struct_methods(tree t)1725 finish_struct_methods (tree t)
1726 {
1727 tree fn_fields;
1728 VEC(tree,gc) *method_vec;
1729 int slot, len;
1730
1731 method_vec = CLASSTYPE_METHOD_VEC (t);
1732 if (!method_vec)
1733 return;
1734
1735 len = VEC_length (tree, method_vec);
1736
1737 /* Clear DECL_IN_AGGR_P for all functions. */
1738 for (fn_fields = TYPE_METHODS (t); fn_fields;
1739 fn_fields = TREE_CHAIN (fn_fields))
1740 DECL_IN_AGGR_P (fn_fields) = 0;
1741
1742 /* Issue warnings about private constructors and such. If there are
1743 no methods, then some public defaults are generated. */
1744 maybe_warn_about_overly_private_class (t);
1745
1746 /* The type conversion ops have to live at the front of the vec, so we
1747 can't sort them. */
1748 for (slot = CLASSTYPE_FIRST_CONVERSION_SLOT;
1749 VEC_iterate (tree, method_vec, slot, fn_fields);
1750 ++slot)
1751 if (!DECL_CONV_FN_P (OVL_CURRENT (fn_fields)))
1752 break;
1753 if (len - slot > 1)
1754 qsort (VEC_address (tree, method_vec) + slot,
1755 len-slot, sizeof (tree), method_name_cmp);
1756 }
1757
1758 /* Make BINFO's vtable have N entries, including RTTI entries,
1759 vbase and vcall offsets, etc. Set its type and call the backend
1760 to lay it out. */
1761
1762 static void
layout_vtable_decl(tree binfo,int n)1763 layout_vtable_decl (tree binfo, int n)
1764 {
1765 tree atype;
1766 tree vtable;
1767
1768 atype = build_cplus_array_type (vtable_entry_type,
1769 build_index_type (size_int (n - 1)));
1770 layout_type (atype);
1771
1772 /* We may have to grow the vtable. */
1773 vtable = get_vtbl_decl_for_binfo (binfo);
1774 if (!same_type_p (TREE_TYPE (vtable), atype))
1775 {
1776 TREE_TYPE (vtable) = atype;
1777 DECL_SIZE (vtable) = DECL_SIZE_UNIT (vtable) = NULL_TREE;
1778 layout_decl (vtable, 0);
1779 }
1780 }
1781
1782 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
1783 have the same signature. */
1784
1785 int
same_signature_p(tree fndecl,tree base_fndecl)1786 same_signature_p (tree fndecl, tree base_fndecl)
1787 {
1788 /* One destructor overrides another if they are the same kind of
1789 destructor. */
1790 if (DECL_DESTRUCTOR_P (base_fndecl) && DECL_DESTRUCTOR_P (fndecl)
1791 && special_function_p (base_fndecl) == special_function_p (fndecl))
1792 return 1;
1793 /* But a non-destructor never overrides a destructor, nor vice
1794 versa, nor do different kinds of destructors override
1795 one-another. For example, a complete object destructor does not
1796 override a deleting destructor. */
1797 if (DECL_DESTRUCTOR_P (base_fndecl) || DECL_DESTRUCTOR_P (fndecl))
1798 return 0;
1799
1800 if (DECL_NAME (fndecl) == DECL_NAME (base_fndecl)
1801 || (DECL_CONV_FN_P (fndecl)
1802 && DECL_CONV_FN_P (base_fndecl)
1803 && same_type_p (DECL_CONV_FN_TYPE (fndecl),
1804 DECL_CONV_FN_TYPE (base_fndecl))))
1805 {
1806 tree types, base_types;
1807 types = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
1808 base_types = TYPE_ARG_TYPES (TREE_TYPE (base_fndecl));
1809 if ((TYPE_QUALS (TREE_TYPE (TREE_VALUE (base_types)))
1810 == TYPE_QUALS (TREE_TYPE (TREE_VALUE (types))))
1811 && compparms (TREE_CHAIN (base_types), TREE_CHAIN (types)))
1812 return 1;
1813 }
1814 return 0;
1815 }
1816
1817 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
1818 subobject. */
1819
1820 static bool
base_derived_from(tree derived,tree base)1821 base_derived_from (tree derived, tree base)
1822 {
1823 tree probe;
1824
1825 for (probe = base; probe; probe = BINFO_INHERITANCE_CHAIN (probe))
1826 {
1827 if (probe == derived)
1828 return true;
1829 else if (BINFO_VIRTUAL_P (probe))
1830 /* If we meet a virtual base, we can't follow the inheritance
1831 any more. See if the complete type of DERIVED contains
1832 such a virtual base. */
1833 return (binfo_for_vbase (BINFO_TYPE (probe), BINFO_TYPE (derived))
1834 != NULL_TREE);
1835 }
1836 return false;
1837 }
1838
1839 typedef struct find_final_overrider_data_s {
1840 /* The function for which we are trying to find a final overrider. */
1841 tree fn;
1842 /* The base class in which the function was declared. */
1843 tree declaring_base;
1844 /* The candidate overriders. */
1845 tree candidates;
1846 /* Path to most derived. */
1847 VEC(tree,heap) *path;
1848 } find_final_overrider_data;
1849
1850 /* Add the overrider along the current path to FFOD->CANDIDATES.
1851 Returns true if an overrider was found; false otherwise. */
1852
1853 static bool
dfs_find_final_overrider_1(tree binfo,find_final_overrider_data * ffod,unsigned depth)1854 dfs_find_final_overrider_1 (tree binfo,
1855 find_final_overrider_data *ffod,
1856 unsigned depth)
1857 {
1858 tree method;
1859
1860 /* If BINFO is not the most derived type, try a more derived class.
1861 A definition there will overrider a definition here. */
1862 if (depth)
1863 {
1864 depth--;
1865 if (dfs_find_final_overrider_1
1866 (VEC_index (tree, ffod->path, depth), ffod, depth))
1867 return true;
1868 }
1869
1870 method = look_for_overrides_here (BINFO_TYPE (binfo), ffod->fn);
1871 if (method)
1872 {
1873 tree *candidate = &ffod->candidates;
1874
1875 /* Remove any candidates overridden by this new function. */
1876 while (*candidate)
1877 {
1878 /* If *CANDIDATE overrides METHOD, then METHOD
1879 cannot override anything else on the list. */
1880 if (base_derived_from (TREE_VALUE (*candidate), binfo))
1881 return true;
1882 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
1883 if (base_derived_from (binfo, TREE_VALUE (*candidate)))
1884 *candidate = TREE_CHAIN (*candidate);
1885 else
1886 candidate = &TREE_CHAIN (*candidate);
1887 }
1888
1889 /* Add the new function. */
1890 ffod->candidates = tree_cons (method, binfo, ffod->candidates);
1891 return true;
1892 }
1893
1894 return false;
1895 }
1896
1897 /* Called from find_final_overrider via dfs_walk. */
1898
1899 static tree
dfs_find_final_overrider_pre(tree binfo,void * data)1900 dfs_find_final_overrider_pre (tree binfo, void *data)
1901 {
1902 find_final_overrider_data *ffod = (find_final_overrider_data *) data;
1903
1904 if (binfo == ffod->declaring_base)
1905 dfs_find_final_overrider_1 (binfo, ffod, VEC_length (tree, ffod->path));
1906 VEC_safe_push (tree, heap, ffod->path, binfo);
1907
1908 return NULL_TREE;
1909 }
1910
1911 static tree
dfs_find_final_overrider_post(tree binfo ATTRIBUTE_UNUSED,void * data)1912 dfs_find_final_overrider_post (tree binfo ATTRIBUTE_UNUSED, void *data)
1913 {
1914 find_final_overrider_data *ffod = (find_final_overrider_data *) data;
1915 VEC_pop (tree, ffod->path);
1916
1917 return NULL_TREE;
1918 }
1919
1920 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
1921 FN and whose TREE_VALUE is the binfo for the base where the
1922 overriding occurs. BINFO (in the hierarchy dominated by the binfo
1923 DERIVED) is the base object in which FN is declared. */
1924
1925 static tree
find_final_overrider(tree derived,tree binfo,tree fn)1926 find_final_overrider (tree derived, tree binfo, tree fn)
1927 {
1928 find_final_overrider_data ffod;
1929
1930 /* Getting this right is a little tricky. This is valid:
1931
1932 struct S { virtual void f (); };
1933 struct T { virtual void f (); };
1934 struct U : public S, public T { };
1935
1936 even though calling `f' in `U' is ambiguous. But,
1937
1938 struct R { virtual void f(); };
1939 struct S : virtual public R { virtual void f (); };
1940 struct T : virtual public R { virtual void f (); };
1941 struct U : public S, public T { };
1942
1943 is not -- there's no way to decide whether to put `S::f' or
1944 `T::f' in the vtable for `R'.
1945
1946 The solution is to look at all paths to BINFO. If we find
1947 different overriders along any two, then there is a problem. */
1948 if (DECL_THUNK_P (fn))
1949 fn = THUNK_TARGET (fn);
1950
1951 /* Determine the depth of the hierarchy. */
1952 ffod.fn = fn;
1953 ffod.declaring_base = binfo;
1954 ffod.candidates = NULL_TREE;
1955 ffod.path = VEC_alloc (tree, heap, 30);
1956
1957 dfs_walk_all (derived, dfs_find_final_overrider_pre,
1958 dfs_find_final_overrider_post, &ffod);
1959
1960 VEC_free (tree, heap, ffod.path);
1961
1962 /* If there was no winner, issue an error message. */
1963 if (!ffod.candidates || TREE_CHAIN (ffod.candidates))
1964 return error_mark_node;
1965
1966 return ffod.candidates;
1967 }
1968
1969 /* Return the index of the vcall offset for FN when TYPE is used as a
1970 virtual base. */
1971
1972 static tree
get_vcall_index(tree fn,tree type)1973 get_vcall_index (tree fn, tree type)
1974 {
1975 VEC(tree_pair_s,gc) *indices = CLASSTYPE_VCALL_INDICES (type);
1976 tree_pair_p p;
1977 unsigned ix;
1978
1979 for (ix = 0; VEC_iterate (tree_pair_s, indices, ix, p); ix++)
1980 if ((DECL_DESTRUCTOR_P (fn) && DECL_DESTRUCTOR_P (p->purpose))
1981 || same_signature_p (fn, p->purpose))
1982 return p->value;
1983
1984 /* There should always be an appropriate index. */
1985 gcc_unreachable ();
1986 }
1987
1988 /* Update an entry in the vtable for BINFO, which is in the hierarchy
1989 dominated by T. FN has been overridden in BINFO; VIRTUALS points to the
1990 corresponding position in the BINFO_VIRTUALS list. */
1991
1992 static void
update_vtable_entry_for_fn(tree t,tree binfo,tree fn,tree * virtuals,unsigned ix)1993 update_vtable_entry_for_fn (tree t, tree binfo, tree fn, tree* virtuals,
1994 unsigned ix)
1995 {
1996 tree b;
1997 tree overrider;
1998 tree delta;
1999 tree virtual_base;
2000 tree first_defn;
2001 tree overrider_fn, overrider_target;
2002 tree target_fn = DECL_THUNK_P (fn) ? THUNK_TARGET (fn) : fn;
2003 tree over_return, base_return;
2004 bool lost = false;
2005
2006 /* Find the nearest primary base (possibly binfo itself) which defines
2007 this function; this is the class the caller will convert to when
2008 calling FN through BINFO. */
2009 for (b = binfo; ; b = get_primary_binfo (b))
2010 {
2011 gcc_assert (b);
2012 if (look_for_overrides_here (BINFO_TYPE (b), target_fn))
2013 break;
2014
2015 /* The nearest definition is from a lost primary. */
2016 if (BINFO_LOST_PRIMARY_P (b))
2017 lost = true;
2018 }
2019 first_defn = b;
2020
2021 /* Find the final overrider. */
2022 overrider = find_final_overrider (TYPE_BINFO (t), b, target_fn);
2023 if (overrider == error_mark_node)
2024 {
2025 error ("no unique final overrider for %qD in %qT", target_fn, t);
2026 return;
2027 }
2028 overrider_target = overrider_fn = TREE_PURPOSE (overrider);
2029
2030 /* Check for adjusting covariant return types. */
2031 over_return = TREE_TYPE (TREE_TYPE (overrider_target));
2032 base_return = TREE_TYPE (TREE_TYPE (target_fn));
2033
2034 if (POINTER_TYPE_P (over_return)
2035 && TREE_CODE (over_return) == TREE_CODE (base_return)
2036 && CLASS_TYPE_P (TREE_TYPE (over_return))
2037 && CLASS_TYPE_P (TREE_TYPE (base_return))
2038 /* If the overrider is invalid, don't even try. */
2039 && !DECL_INVALID_OVERRIDER_P (overrider_target))
2040 {
2041 /* If FN is a covariant thunk, we must figure out the adjustment
2042 to the final base FN was converting to. As OVERRIDER_TARGET might
2043 also be converting to the return type of FN, we have to
2044 combine the two conversions here. */
2045 tree fixed_offset, virtual_offset;
2046
2047 over_return = TREE_TYPE (over_return);
2048 base_return = TREE_TYPE (base_return);
2049
2050 if (DECL_THUNK_P (fn))
2051 {
2052 gcc_assert (DECL_RESULT_THUNK_P (fn));
2053 fixed_offset = ssize_int (THUNK_FIXED_OFFSET (fn));
2054 virtual_offset = THUNK_VIRTUAL_OFFSET (fn);
2055 }
2056 else
2057 fixed_offset = virtual_offset = NULL_TREE;
2058
2059 if (virtual_offset)
2060 /* Find the equivalent binfo within the return type of the
2061 overriding function. We will want the vbase offset from
2062 there. */
2063 virtual_offset = binfo_for_vbase (BINFO_TYPE (virtual_offset),
2064 over_return);
2065 else if (!same_type_ignoring_top_level_qualifiers_p
2066 (over_return, base_return))
2067 {
2068 /* There was no existing virtual thunk (which takes
2069 precedence). So find the binfo of the base function's
2070 return type within the overriding function's return type.
2071 We cannot call lookup base here, because we're inside a
2072 dfs_walk, and will therefore clobber the BINFO_MARKED
2073 flags. Fortunately we know the covariancy is valid (it
2074 has already been checked), so we can just iterate along
2075 the binfos, which have been chained in inheritance graph
2076 order. Of course it is lame that we have to repeat the
2077 search here anyway -- we should really be caching pieces
2078 of the vtable and avoiding this repeated work. */
2079 tree thunk_binfo, base_binfo;
2080
2081 /* Find the base binfo within the overriding function's
2082 return type. We will always find a thunk_binfo, except
2083 when the covariancy is invalid (which we will have
2084 already diagnosed). */
2085 for (base_binfo = TYPE_BINFO (base_return),
2086 thunk_binfo = TYPE_BINFO (over_return);
2087 thunk_binfo;
2088 thunk_binfo = TREE_CHAIN (thunk_binfo))
2089 if (SAME_BINFO_TYPE_P (BINFO_TYPE (thunk_binfo),
2090 BINFO_TYPE (base_binfo)))
2091 break;
2092
2093 /* See if virtual inheritance is involved. */
2094 for (virtual_offset = thunk_binfo;
2095 virtual_offset;
2096 virtual_offset = BINFO_INHERITANCE_CHAIN (virtual_offset))
2097 if (BINFO_VIRTUAL_P (virtual_offset))
2098 break;
2099
2100 if (virtual_offset
2101 || (thunk_binfo && !BINFO_OFFSET_ZEROP (thunk_binfo)))
2102 {
2103 tree offset = convert (ssizetype, BINFO_OFFSET (thunk_binfo));
2104
2105 if (virtual_offset)
2106 {
2107 /* We convert via virtual base. Adjust the fixed
2108 offset to be from there. */
2109 offset = size_diffop
2110 (offset, convert
2111 (ssizetype, BINFO_OFFSET (virtual_offset)));
2112 }
2113 if (fixed_offset)
2114 /* There was an existing fixed offset, this must be
2115 from the base just converted to, and the base the
2116 FN was thunking to. */
2117 fixed_offset = size_binop (PLUS_EXPR, fixed_offset, offset);
2118 else
2119 fixed_offset = offset;
2120 }
2121 }
2122
2123 if (fixed_offset || virtual_offset)
2124 /* Replace the overriding function with a covariant thunk. We
2125 will emit the overriding function in its own slot as
2126 well. */
2127 overrider_fn = make_thunk (overrider_target, /*this_adjusting=*/0,
2128 fixed_offset, virtual_offset);
2129 }
2130 else
2131 gcc_assert (!DECL_THUNK_P (fn));
2132
2133 /* Assume that we will produce a thunk that convert all the way to
2134 the final overrider, and not to an intermediate virtual base. */
2135 virtual_base = NULL_TREE;
2136
2137 /* See if we can convert to an intermediate virtual base first, and then
2138 use the vcall offset located there to finish the conversion. */
2139 for (; b; b = BINFO_INHERITANCE_CHAIN (b))
2140 {
2141 /* If we find the final overrider, then we can stop
2142 walking. */
2143 if (SAME_BINFO_TYPE_P (BINFO_TYPE (b),
2144 BINFO_TYPE (TREE_VALUE (overrider))))
2145 break;
2146
2147 /* If we find a virtual base, and we haven't yet found the
2148 overrider, then there is a virtual base between the
2149 declaring base (first_defn) and the final overrider. */
2150 if (BINFO_VIRTUAL_P (b))
2151 {
2152 virtual_base = b;
2153 break;
2154 }
2155 }
2156
2157 if (overrider_fn != overrider_target && !virtual_base)
2158 {
2159 /* The ABI specifies that a covariant thunk includes a mangling
2160 for a this pointer adjustment. This-adjusting thunks that
2161 override a function from a virtual base have a vcall
2162 adjustment. When the virtual base in question is a primary
2163 virtual base, we know the adjustments are zero, (and in the
2164 non-covariant case, we would not use the thunk).
2165 Unfortunately we didn't notice this could happen, when
2166 designing the ABI and so never mandated that such a covariant
2167 thunk should be emitted. Because we must use the ABI mandated
2168 name, we must continue searching from the binfo where we
2169 found the most recent definition of the function, towards the
2170 primary binfo which first introduced the function into the
2171 vtable. If that enters a virtual base, we must use a vcall
2172 this-adjusting thunk. Bleah! */
2173 tree probe = first_defn;
2174
2175 while ((probe = get_primary_binfo (probe))
2176 && (unsigned) list_length (BINFO_VIRTUALS (probe)) > ix)
2177 if (BINFO_VIRTUAL_P (probe))
2178 virtual_base = probe;
2179
2180 if (virtual_base)
2181 /* Even if we find a virtual base, the correct delta is
2182 between the overrider and the binfo we're building a vtable
2183 for. */
2184 goto virtual_covariant;
2185 }
2186
2187 /* Compute the constant adjustment to the `this' pointer. The
2188 `this' pointer, when this function is called, will point at BINFO
2189 (or one of its primary bases, which are at the same offset). */
2190 if (virtual_base)
2191 /* The `this' pointer needs to be adjusted from the declaration to
2192 the nearest virtual base. */
2193 delta = size_diffop (convert (ssizetype, BINFO_OFFSET (virtual_base)),
2194 convert (ssizetype, BINFO_OFFSET (first_defn)));
2195 else if (lost)
2196 /* If the nearest definition is in a lost primary, we don't need an
2197 entry in our vtable. Except possibly in a constructor vtable,
2198 if we happen to get our primary back. In that case, the offset
2199 will be zero, as it will be a primary base. */
2200 delta = size_zero_node;
2201 else
2202 /* The `this' pointer needs to be adjusted from pointing to
2203 BINFO to pointing at the base where the final overrider
2204 appears. */
2205 virtual_covariant:
2206 delta = size_diffop (convert (ssizetype,
2207 BINFO_OFFSET (TREE_VALUE (overrider))),
2208 convert (ssizetype, BINFO_OFFSET (binfo)));
2209
2210 modify_vtable_entry (t, binfo, overrider_fn, delta, virtuals);
2211
2212 if (virtual_base)
2213 BV_VCALL_INDEX (*virtuals)
2214 = get_vcall_index (overrider_target, BINFO_TYPE (virtual_base));
2215 else
2216 BV_VCALL_INDEX (*virtuals) = NULL_TREE;
2217 }
2218
2219 /* Called from modify_all_vtables via dfs_walk. */
2220
2221 static tree
dfs_modify_vtables(tree binfo,void * data)2222 dfs_modify_vtables (tree binfo, void* data)
2223 {
2224 tree t = (tree) data;
2225 tree virtuals;
2226 tree old_virtuals;
2227 unsigned ix;
2228
2229 if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
2230 /* A base without a vtable needs no modification, and its bases
2231 are uninteresting. */
2232 return dfs_skip_bases;
2233
2234 if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t)
2235 && !CLASSTYPE_HAS_PRIMARY_BASE_P (t))
2236 /* Don't do the primary vtable, if it's new. */
2237 return NULL_TREE;
2238
2239 if (BINFO_PRIMARY_P (binfo) && !BINFO_VIRTUAL_P (binfo))
2240 /* There's no need to modify the vtable for a non-virtual primary
2241 base; we're not going to use that vtable anyhow. We do still
2242 need to do this for virtual primary bases, as they could become
2243 non-primary in a construction vtable. */
2244 return NULL_TREE;
2245
2246 make_new_vtable (t, binfo);
2247
2248 /* Now, go through each of the virtual functions in the virtual
2249 function table for BINFO. Find the final overrider, and update
2250 the BINFO_VIRTUALS list appropriately. */
2251 for (ix = 0, virtuals = BINFO_VIRTUALS (binfo),
2252 old_virtuals = BINFO_VIRTUALS (TYPE_BINFO (BINFO_TYPE (binfo)));
2253 virtuals;
2254 ix++, virtuals = TREE_CHAIN (virtuals),
2255 old_virtuals = TREE_CHAIN (old_virtuals))
2256 update_vtable_entry_for_fn (t,
2257 binfo,
2258 BV_FN (old_virtuals),
2259 &virtuals, ix);
2260
2261 return NULL_TREE;
2262 }
2263
2264 /* Update all of the primary and secondary vtables for T. Create new
2265 vtables as required, and initialize their RTTI information. Each
2266 of the functions in VIRTUALS is declared in T and may override a
2267 virtual function from a base class; find and modify the appropriate
2268 entries to point to the overriding functions. Returns a list, in
2269 declaration order, of the virtual functions that are declared in T,
2270 but do not appear in the primary base class vtable, and which
2271 should therefore be appended to the end of the vtable for T. */
2272
2273 static tree
modify_all_vtables(tree t,tree virtuals)2274 modify_all_vtables (tree t, tree virtuals)
2275 {
2276 tree binfo = TYPE_BINFO (t);
2277 tree *fnsp;
2278
2279 /* Update all of the vtables. */
2280 dfs_walk_once (binfo, dfs_modify_vtables, NULL, t);
2281
2282 /* Add virtual functions not already in our primary vtable. These
2283 will be both those introduced by this class, and those overridden
2284 from secondary bases. It does not include virtuals merely
2285 inherited from secondary bases. */
2286 for (fnsp = &virtuals; *fnsp; )
2287 {
2288 tree fn = TREE_VALUE (*fnsp);
2289
2290 if (!value_member (fn, BINFO_VIRTUALS (binfo))
2291 || DECL_VINDEX (fn) == error_mark_node)
2292 {
2293 /* We don't need to adjust the `this' pointer when
2294 calling this function. */
2295 BV_DELTA (*fnsp) = integer_zero_node;
2296 BV_VCALL_INDEX (*fnsp) = NULL_TREE;
2297
2298 /* This is a function not already in our vtable. Keep it. */
2299 fnsp = &TREE_CHAIN (*fnsp);
2300 }
2301 else
2302 /* We've already got an entry for this function. Skip it. */
2303 *fnsp = TREE_CHAIN (*fnsp);
2304 }
2305
2306 return virtuals;
2307 }
2308
2309 /* Get the base virtual function declarations in T that have the
2310 indicated NAME. */
2311
2312 static tree
get_basefndecls(tree name,tree t)2313 get_basefndecls (tree name, tree t)
2314 {
2315 tree methods;
2316 tree base_fndecls = NULL_TREE;
2317 int n_baseclasses = BINFO_N_BASE_BINFOS (TYPE_BINFO (t));
2318 int i;
2319
2320 /* Find virtual functions in T with the indicated NAME. */
2321 i = lookup_fnfields_1 (t, name);
2322 if (i != -1)
2323 for (methods = VEC_index (tree, CLASSTYPE_METHOD_VEC (t), i);
2324 methods;
2325 methods = OVL_NEXT (methods))
2326 {
2327 tree method = OVL_CURRENT (methods);
2328
2329 if (TREE_CODE (method) == FUNCTION_DECL
2330 && DECL_VINDEX (method))
2331 base_fndecls = tree_cons (NULL_TREE, method, base_fndecls);
2332 }
2333
2334 if (base_fndecls)
2335 return base_fndecls;
2336
2337 for (i = 0; i < n_baseclasses; i++)
2338 {
2339 tree basetype = BINFO_TYPE (BINFO_BASE_BINFO (TYPE_BINFO (t), i));
2340 base_fndecls = chainon (get_basefndecls (name, basetype),
2341 base_fndecls);
2342 }
2343
2344 return base_fndecls;
2345 }
2346
2347 /* If this declaration supersedes the declaration of
2348 a method declared virtual in the base class, then
2349 mark this field as being virtual as well. */
2350
2351 void
check_for_override(tree decl,tree ctype)2352 check_for_override (tree decl, tree ctype)
2353 {
2354 if (TREE_CODE (decl) == TEMPLATE_DECL)
2355 /* In [temp.mem] we have:
2356
2357 A specialization of a member function template does not
2358 override a virtual function from a base class. */
2359 return;
2360 if ((DECL_DESTRUCTOR_P (decl)
2361 || IDENTIFIER_VIRTUAL_P (DECL_NAME (decl))
2362 || DECL_CONV_FN_P (decl))
2363 && look_for_overrides (ctype, decl)
2364 && !DECL_STATIC_FUNCTION_P (decl))
2365 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2366 the error_mark_node so that we know it is an overriding
2367 function. */
2368 DECL_VINDEX (decl) = decl;
2369
2370 if (DECL_VIRTUAL_P (decl))
2371 {
2372 if (!DECL_VINDEX (decl))
2373 DECL_VINDEX (decl) = error_mark_node;
2374 IDENTIFIER_VIRTUAL_P (DECL_NAME (decl)) = 1;
2375 if (DECL_DLLIMPORT_P (decl))
2376 {
2377 /* When we handled the dllimport attribute we may not have known
2378 that this function is virtual We can't use dllimport
2379 semantics for a virtual method because we need to initialize
2380 the vtable entry with a constant address. */
2381 DECL_DLLIMPORT_P (decl) = 0;
2382 DECL_ATTRIBUTES (decl)
2383 = remove_attribute ("dllimport", DECL_ATTRIBUTES (decl));
2384 }
2385 }
2386 }
2387
2388 /* Warn about hidden virtual functions that are not overridden in t.
2389 We know that constructors and destructors don't apply. */
2390
2391 static void
warn_hidden(tree t)2392 warn_hidden (tree t)
2393 {
2394 VEC(tree,gc) *method_vec = CLASSTYPE_METHOD_VEC (t);
2395 tree fns;
2396 size_t i;
2397
2398 /* We go through each separately named virtual function. */
2399 for (i = CLASSTYPE_FIRST_CONVERSION_SLOT;
2400 VEC_iterate (tree, method_vec, i, fns);
2401 ++i)
2402 {
2403 tree fn;
2404 tree name;
2405 tree fndecl;
2406 tree base_fndecls;
2407 tree base_binfo;
2408 tree binfo;
2409 int j;
2410
2411 /* All functions in this slot in the CLASSTYPE_METHOD_VEC will
2412 have the same name. Figure out what name that is. */
2413 name = DECL_NAME (OVL_CURRENT (fns));
2414 /* There are no possibly hidden functions yet. */
2415 base_fndecls = NULL_TREE;
2416 /* Iterate through all of the base classes looking for possibly
2417 hidden functions. */
2418 for (binfo = TYPE_BINFO (t), j = 0;
2419 BINFO_BASE_ITERATE (binfo, j, base_binfo); j++)
2420 {
2421 tree basetype = BINFO_TYPE (base_binfo);
2422 base_fndecls = chainon (get_basefndecls (name, basetype),
2423 base_fndecls);
2424 }
2425
2426 /* If there are no functions to hide, continue. */
2427 if (!base_fndecls)
2428 continue;
2429
2430 /* Remove any overridden functions. */
2431 for (fn = fns; fn; fn = OVL_NEXT (fn))
2432 {
2433 fndecl = OVL_CURRENT (fn);
2434 if (DECL_VINDEX (fndecl))
2435 {
2436 tree *prev = &base_fndecls;
2437
2438 while (*prev)
2439 /* If the method from the base class has the same
2440 signature as the method from the derived class, it
2441 has been overridden. */
2442 if (same_signature_p (fndecl, TREE_VALUE (*prev)))
2443 *prev = TREE_CHAIN (*prev);
2444 else
2445 prev = &TREE_CHAIN (*prev);
2446 }
2447 }
2448
2449 /* Now give a warning for all base functions without overriders,
2450 as they are hidden. */
2451 while (base_fndecls)
2452 {
2453 /* Here we know it is a hider, and no overrider exists. */
2454 warning (0, "%q+D was hidden", TREE_VALUE (base_fndecls));
2455 warning (0, " by %q+D", fns);
2456 base_fndecls = TREE_CHAIN (base_fndecls);
2457 }
2458 }
2459 }
2460
2461 /* Check for things that are invalid. There are probably plenty of other
2462 things we should check for also. */
2463
2464 static void
finish_struct_anon(tree t)2465 finish_struct_anon (tree t)
2466 {
2467 tree field;
2468
2469 for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
2470 {
2471 if (TREE_STATIC (field))
2472 continue;
2473 if (TREE_CODE (field) != FIELD_DECL)
2474 continue;
2475
2476 if (DECL_NAME (field) == NULL_TREE
2477 && ANON_AGGR_TYPE_P (TREE_TYPE (field)))
2478 {
2479 tree elt = TYPE_FIELDS (TREE_TYPE (field));
2480 for (; elt; elt = TREE_CHAIN (elt))
2481 {
2482 /* We're generally only interested in entities the user
2483 declared, but we also find nested classes by noticing
2484 the TYPE_DECL that we create implicitly. You're
2485 allowed to put one anonymous union inside another,
2486 though, so we explicitly tolerate that. We use
2487 TYPE_ANONYMOUS_P rather than ANON_AGGR_TYPE_P so that
2488 we also allow unnamed types used for defining fields. */
2489 if (DECL_ARTIFICIAL (elt)
2490 && (!DECL_IMPLICIT_TYPEDEF_P (elt)
2491 || TYPE_ANONYMOUS_P (TREE_TYPE (elt))))
2492 continue;
2493
2494 if (TREE_CODE (elt) != FIELD_DECL)
2495 {
2496 pedwarn ("%q+#D invalid; an anonymous union can "
2497 "only have non-static data members", elt);
2498 continue;
2499 }
2500
2501 if (TREE_PRIVATE (elt))
2502 pedwarn ("private member %q+#D in anonymous union", elt);
2503 else if (TREE_PROTECTED (elt))
2504 pedwarn ("protected member %q+#D in anonymous union", elt);
2505
2506 TREE_PRIVATE (elt) = TREE_PRIVATE (field);
2507 TREE_PROTECTED (elt) = TREE_PROTECTED (field);
2508 }
2509 }
2510 }
2511 }
2512
2513 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2514 will be used later during class template instantiation.
2515 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2516 a non-static member data (FIELD_DECL), a member function
2517 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2518 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2519 When FRIEND_P is nonzero, T is either a friend class
2520 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2521 (FUNCTION_DECL, TEMPLATE_DECL). */
2522
2523 void
maybe_add_class_template_decl_list(tree type,tree t,int friend_p)2524 maybe_add_class_template_decl_list (tree type, tree t, int friend_p)
2525 {
2526 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
2527 if (CLASSTYPE_TEMPLATE_INFO (type))
2528 CLASSTYPE_DECL_LIST (type)
2529 = tree_cons (friend_p ? NULL_TREE : type,
2530 t, CLASSTYPE_DECL_LIST (type));
2531 }
2532
2533 /* Create default constructors, assignment operators, and so forth for
2534 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
2535 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
2536 the class cannot have a default constructor, copy constructor
2537 taking a const reference argument, or an assignment operator taking
2538 a const reference, respectively. */
2539
2540 static void
add_implicitly_declared_members(tree t,int cant_have_const_cctor,int cant_have_const_assignment)2541 add_implicitly_declared_members (tree t,
2542 int cant_have_const_cctor,
2543 int cant_have_const_assignment)
2544 {
2545 /* Destructor. */
2546 if (!CLASSTYPE_DESTRUCTORS (t))
2547 {
2548 /* In general, we create destructors lazily. */
2549 CLASSTYPE_LAZY_DESTRUCTOR (t) = 1;
2550 /* However, if the implicit destructor is non-trivial
2551 destructor, we sometimes have to create it at this point. */
2552 if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t))
2553 {
2554 bool lazy_p = true;
2555
2556 /* APPLE LOCAL begin omit calls to empty destructors 5559195 */
2557 /* Since this is an empty destructor, it can only be nontrivial
2558 because one of its base classes has a destructor that must be
2559 called. */
2560 CLASSTYPE_DESTRUCTOR_NONTRIVIAL_BECAUSE_OF_BASE (t) = 1;
2561 /* APPLE LOCAL end omit calls to empty destructors 5559195 */
2562
2563 if (TYPE_FOR_JAVA (t))
2564 /* If this a Java class, any non-trivial destructor is
2565 invalid, even if compiler-generated. Therefore, if the
2566 destructor is non-trivial we create it now. */
2567 lazy_p = false;
2568 else
2569 {
2570 tree binfo;
2571 tree base_binfo;
2572 int ix;
2573
2574 /* If the implicit destructor will be virtual, then we must
2575 generate it now because (unfortunately) we do not
2576 generate virtual tables lazily. */
2577 binfo = TYPE_BINFO (t);
2578 for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++)
2579 {
2580 tree base_type;
2581 tree dtor;
2582
2583 base_type = BINFO_TYPE (base_binfo);
2584 dtor = CLASSTYPE_DESTRUCTORS (base_type);
2585 if (dtor && DECL_VIRTUAL_P (dtor))
2586 {
2587 lazy_p = false;
2588 break;
2589 }
2590 }
2591 }
2592
2593 /* If we can't get away with being lazy, generate the destructor
2594 now. */
2595 if (!lazy_p)
2596 lazily_declare_fn (sfk_destructor, t);
2597 }
2598 }
2599
2600 /* Default constructor. */
2601 if (! TYPE_HAS_CONSTRUCTOR (t))
2602 {
2603 TYPE_HAS_DEFAULT_CONSTRUCTOR (t) = 1;
2604 CLASSTYPE_LAZY_DEFAULT_CTOR (t) = 1;
2605 }
2606
2607 /* Copy constructor. */
2608 if (! TYPE_HAS_INIT_REF (t) && ! TYPE_FOR_JAVA (t))
2609 {
2610 TYPE_HAS_INIT_REF (t) = 1;
2611 TYPE_HAS_CONST_INIT_REF (t) = !cant_have_const_cctor;
2612 CLASSTYPE_LAZY_COPY_CTOR (t) = 1;
2613 TYPE_HAS_CONSTRUCTOR (t) = 1;
2614 }
2615
2616 /* If there is no assignment operator, one will be created if and
2617 when it is needed. For now, just record whether or not the type
2618 of the parameter to the assignment operator will be a const or
2619 non-const reference. */
2620 if (!TYPE_HAS_ASSIGN_REF (t) && !TYPE_FOR_JAVA (t))
2621 {
2622 TYPE_HAS_ASSIGN_REF (t) = 1;
2623 TYPE_HAS_CONST_ASSIGN_REF (t) = !cant_have_const_assignment;
2624 CLASSTYPE_LAZY_ASSIGNMENT_OP (t) = 1;
2625 }
2626 }
2627
2628 /* Subroutine of finish_struct_1. Recursively count the number of fields
2629 in TYPE, including anonymous union members. */
2630
2631 static int
count_fields(tree fields)2632 count_fields (tree fields)
2633 {
2634 tree x;
2635 int n_fields = 0;
2636 for (x = fields; x; x = TREE_CHAIN (x))
2637 {
2638 if (TREE_CODE (x) == FIELD_DECL && ANON_AGGR_TYPE_P (TREE_TYPE (x)))
2639 n_fields += count_fields (TYPE_FIELDS (TREE_TYPE (x)));
2640 else
2641 n_fields += 1;
2642 }
2643 return n_fields;
2644 }
2645
2646 /* Subroutine of finish_struct_1. Recursively add all the fields in the
2647 TREE_LIST FIELDS to the SORTED_FIELDS_TYPE elts, starting at offset IDX. */
2648
2649 static int
add_fields_to_record_type(tree fields,struct sorted_fields_type * field_vec,int idx)2650 add_fields_to_record_type (tree fields, struct sorted_fields_type *field_vec, int idx)
2651 {
2652 tree x;
2653 for (x = fields; x; x = TREE_CHAIN (x))
2654 {
2655 if (TREE_CODE (x) == FIELD_DECL && ANON_AGGR_TYPE_P (TREE_TYPE (x)))
2656 idx = add_fields_to_record_type (TYPE_FIELDS (TREE_TYPE (x)), field_vec, idx);
2657 else
2658 field_vec->elts[idx++] = x;
2659 }
2660 return idx;
2661 }
2662
2663 /* FIELD is a bit-field. We are finishing the processing for its
2664 enclosing type. Issue any appropriate messages and set appropriate
2665 flags. */
2666
2667 static void
check_bitfield_decl(tree field)2668 check_bitfield_decl (tree field)
2669 {
2670 tree type = TREE_TYPE (field);
2671 tree w;
2672
2673 /* Extract the declared width of the bitfield, which has been
2674 temporarily stashed in DECL_INITIAL. */
2675 w = DECL_INITIAL (field);
2676 gcc_assert (w != NULL_TREE);
2677 /* Remove the bit-field width indicator so that the rest of the
2678 compiler does not treat that value as an initializer. */
2679 DECL_INITIAL (field) = NULL_TREE;
2680
2681 /* Detect invalid bit-field type. */
2682 if (!INTEGRAL_TYPE_P (type))
2683 {
2684 error ("bit-field %q+#D with non-integral type", field);
2685 TREE_TYPE (field) = error_mark_node;
2686 w = error_mark_node;
2687 }
2688 else
2689 {
2690 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
2691 STRIP_NOPS (w);
2692
2693 /* detect invalid field size. */
2694 w = integral_constant_value (w);
2695
2696 if (TREE_CODE (w) != INTEGER_CST)
2697 {
2698 error ("bit-field %q+D width not an integer constant", field);
2699 w = error_mark_node;
2700 }
2701 else if (tree_int_cst_sgn (w) < 0)
2702 {
2703 error ("negative width in bit-field %q+D", field);
2704 w = error_mark_node;
2705 }
2706 else if (integer_zerop (w) && DECL_NAME (field) != 0)
2707 {
2708 error ("zero width for bit-field %q+D", field);
2709 w = error_mark_node;
2710 }
2711 else if (compare_tree_int (w, TYPE_PRECISION (type)) > 0
2712 && TREE_CODE (type) != ENUMERAL_TYPE
2713 && TREE_CODE (type) != BOOLEAN_TYPE)
2714 warning (0, "width of %q+D exceeds its type", field);
2715 else if (TREE_CODE (type) == ENUMERAL_TYPE
2716 && (0 > compare_tree_int (w,
2717 min_precision (TYPE_MIN_VALUE (type),
2718 TYPE_UNSIGNED (type)))
2719 || 0 > compare_tree_int (w,
2720 min_precision
2721 (TYPE_MAX_VALUE (type),
2722 TYPE_UNSIGNED (type)))))
2723 warning (0, "%q+D is too small to hold all values of %q#T", field, type);
2724 }
2725
2726 if (w != error_mark_node)
2727 {
2728 DECL_SIZE (field) = convert (bitsizetype, w);
2729 DECL_BIT_FIELD (field) = 1;
2730 }
2731 else
2732 {
2733 /* Non-bit-fields are aligned for their type. */
2734 DECL_BIT_FIELD (field) = 0;
2735 CLEAR_DECL_C_BIT_FIELD (field);
2736 }
2737 }
2738
2739 /* FIELD is a non bit-field. We are finishing the processing for its
2740 enclosing type T. Issue any appropriate messages and set appropriate
2741 flags. */
2742
2743 static void
check_field_decl(tree field,tree t,int * cant_have_const_ctor,int * no_const_asn_ref,int * any_default_members)2744 check_field_decl (tree field,
2745 tree t,
2746 int* cant_have_const_ctor,
2747 int* no_const_asn_ref,
2748 int* any_default_members)
2749 {
2750 tree type = strip_array_types (TREE_TYPE (field));
2751
2752 /* An anonymous union cannot contain any fields which would change
2753 the settings of CANT_HAVE_CONST_CTOR and friends. */
2754 if (ANON_UNION_TYPE_P (type))
2755 ;
2756 /* And, we don't set TYPE_HAS_CONST_INIT_REF, etc., for anonymous
2757 structs. So, we recurse through their fields here. */
2758 else if (ANON_AGGR_TYPE_P (type))
2759 {
2760 tree fields;
2761
2762 for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields))
2763 if (TREE_CODE (fields) == FIELD_DECL && !DECL_C_BIT_FIELD (field))
2764 check_field_decl (fields, t, cant_have_const_ctor,
2765 no_const_asn_ref, any_default_members);
2766 }
2767 /* Check members with class type for constructors, destructors,
2768 etc. */
2769 else if (CLASS_TYPE_P (type))
2770 {
2771 /* Never let anything with uninheritable virtuals
2772 make it through without complaint. */
2773 abstract_virtuals_error (field, type);
2774
2775 if (TREE_CODE (t) == UNION_TYPE)
2776 {
2777 if (TYPE_NEEDS_CONSTRUCTING (type))
2778 error ("member %q+#D with constructor not allowed in union",
2779 field);
2780 if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
2781 error ("member %q+#D with destructor not allowed in union", field);
2782 if (TYPE_HAS_COMPLEX_ASSIGN_REF (type))
2783 error ("member %q+#D with copy assignment operator not allowed in union",
2784 field);
2785 }
2786 else
2787 {
2788 TYPE_NEEDS_CONSTRUCTING (t) |= TYPE_NEEDS_CONSTRUCTING (type);
2789 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
2790 |= TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type);
2791 TYPE_HAS_COMPLEX_ASSIGN_REF (t) |= TYPE_HAS_COMPLEX_ASSIGN_REF (type);
2792 TYPE_HAS_COMPLEX_INIT_REF (t) |= TYPE_HAS_COMPLEX_INIT_REF (type);
2793 }
2794
2795 if (!TYPE_HAS_CONST_INIT_REF (type))
2796 *cant_have_const_ctor = 1;
2797
2798 if (!TYPE_HAS_CONST_ASSIGN_REF (type))
2799 *no_const_asn_ref = 1;
2800 }
2801 if (DECL_INITIAL (field) != NULL_TREE)
2802 {
2803 /* `build_class_init_list' does not recognize
2804 non-FIELD_DECLs. */
2805 if (TREE_CODE (t) == UNION_TYPE && any_default_members != 0)
2806 error ("multiple fields in union %qT initialized", t);
2807 *any_default_members = 1;
2808 }
2809 }
2810
2811 /* Check the data members (both static and non-static), class-scoped
2812 typedefs, etc., appearing in the declaration of T. Issue
2813 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
2814 declaration order) of access declarations; each TREE_VALUE in this
2815 list is a USING_DECL.
2816
2817 In addition, set the following flags:
2818
2819 EMPTY_P
2820 The class is empty, i.e., contains no non-static data members.
2821
2822 CANT_HAVE_CONST_CTOR_P
2823 This class cannot have an implicitly generated copy constructor
2824 taking a const reference.
2825
2826 CANT_HAVE_CONST_ASN_REF
2827 This class cannot have an implicitly generated assignment
2828 operator taking a const reference.
2829
2830 All of these flags should be initialized before calling this
2831 function.
2832
2833 Returns a pointer to the end of the TYPE_FIELDs chain; additional
2834 fields can be added by adding to this chain. */
2835
2836 static void
check_field_decls(tree t,tree * access_decls,int * cant_have_const_ctor_p,int * no_const_asn_ref_p)2837 check_field_decls (tree t, tree *access_decls,
2838 int *cant_have_const_ctor_p,
2839 int *no_const_asn_ref_p)
2840 {
2841 tree *field;
2842 tree *next;
2843 bool has_pointers;
2844 int any_default_members;
2845 int cant_pack = 0;
2846
2847 /* Assume there are no access declarations. */
2848 *access_decls = NULL_TREE;
2849 /* Assume this class has no pointer members. */
2850 has_pointers = false;
2851 /* Assume none of the members of this class have default
2852 initializations. */
2853 any_default_members = 0;
2854
2855 for (field = &TYPE_FIELDS (t); *field; field = next)
2856 {
2857 tree x = *field;
2858 tree type = TREE_TYPE (x);
2859
2860 next = &TREE_CHAIN (x);
2861
2862 if (TREE_CODE (x) == USING_DECL)
2863 {
2864 /* Prune the access declaration from the list of fields. */
2865 *field = TREE_CHAIN (x);
2866
2867 /* Save the access declarations for our caller. */
2868 *access_decls = tree_cons (NULL_TREE, x, *access_decls);
2869
2870 /* Since we've reset *FIELD there's no reason to skip to the
2871 next field. */
2872 next = field;
2873 continue;
2874 }
2875
2876 if (TREE_CODE (x) == TYPE_DECL
2877 || TREE_CODE (x) == TEMPLATE_DECL)
2878 continue;
2879
2880 /* If we've gotten this far, it's a data member, possibly static,
2881 or an enumerator. */
2882 DECL_CONTEXT (x) = t;
2883
2884 /* When this goes into scope, it will be a non-local reference. */
2885 DECL_NONLOCAL (x) = 1;
2886
2887 if (TREE_CODE (t) == UNION_TYPE)
2888 {
2889 /* [class.union]
2890
2891 If a union contains a static data member, or a member of
2892 reference type, the program is ill-formed. */
2893 if (TREE_CODE (x) == VAR_DECL)
2894 {
2895 error ("%q+D may not be static because it is a member of a union", x);
2896 continue;
2897 }
2898 if (TREE_CODE (type) == REFERENCE_TYPE)
2899 {
2900 error ("%q+D may not have reference type %qT because"
2901 " it is a member of a union",
2902 x, type);
2903 continue;
2904 }
2905 }
2906
2907 /* Perform error checking that did not get done in
2908 grokdeclarator. */
2909 if (TREE_CODE (type) == FUNCTION_TYPE)
2910 {
2911 error ("field %q+D invalidly declared function type", x);
2912 type = build_pointer_type (type);
2913 TREE_TYPE (x) = type;
2914 }
2915 else if (TREE_CODE (type) == METHOD_TYPE)
2916 {
2917 error ("field %q+D invalidly declared method type", x);
2918 type = build_pointer_type (type);
2919 TREE_TYPE (x) = type;
2920 }
2921
2922 if (type == error_mark_node)
2923 continue;
2924
2925 if (TREE_CODE (x) == CONST_DECL || TREE_CODE (x) == VAR_DECL)
2926 continue;
2927
2928 /* Now it can only be a FIELD_DECL. */
2929
2930 if (TREE_PRIVATE (x) || TREE_PROTECTED (x))
2931 CLASSTYPE_NON_AGGREGATE (t) = 1;
2932
2933 /* If this is of reference type, check if it needs an init.
2934 Also do a little ANSI jig if necessary. */
2935 if (TREE_CODE (type) == REFERENCE_TYPE)
2936 {
2937 CLASSTYPE_NON_POD_P (t) = 1;
2938 if (DECL_INITIAL (x) == NULL_TREE)
2939 SET_CLASSTYPE_REF_FIELDS_NEED_INIT (t, 1);
2940
2941 /* ARM $12.6.2: [A member initializer list] (or, for an
2942 aggregate, initialization by a brace-enclosed list) is the
2943 only way to initialize nonstatic const and reference
2944 members. */
2945 TYPE_HAS_COMPLEX_ASSIGN_REF (t) = 1;
2946
2947 if (! TYPE_HAS_CONSTRUCTOR (t) && CLASSTYPE_NON_AGGREGATE (t)
2948 && extra_warnings)
2949 warning (OPT_Wextra, "non-static reference %q+#D in class without a constructor", x);
2950 }
2951
2952 type = strip_array_types (type);
2953
2954 if (TYPE_PACKED (t))
2955 {
2956 if (!pod_type_p (type) && !TYPE_PACKED (type))
2957 {
2958 warning
2959 (0,
2960 "ignoring packed attribute because of unpacked non-POD field %q+#D",
2961 x);
2962 cant_pack = 1;
2963 }
2964 else if (TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
2965 DECL_PACKED (x) = 1;
2966 }
2967
2968 if (DECL_C_BIT_FIELD (x) && integer_zerop (DECL_INITIAL (x)))
2969 /* We don't treat zero-width bitfields as making a class
2970 non-empty. */
2971 ;
2972 else
2973 {
2974 /* The class is non-empty. */
2975 CLASSTYPE_EMPTY_P (t) = 0;
2976 /* The class is not even nearly empty. */
2977 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
2978 /* If one of the data members contains an empty class,
2979 so does T. */
2980 if (CLASS_TYPE_P (type)
2981 && CLASSTYPE_CONTAINS_EMPTY_CLASS_P (type))
2982 CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
2983 }
2984
2985 /* This is used by -Weffc++ (see below). Warn only for pointers
2986 to members which might hold dynamic memory. So do not warn
2987 for pointers to functions or pointers to members. */
2988 if (TYPE_PTR_P (type)
2989 && !TYPE_PTRFN_P (type)
2990 && !TYPE_PTR_TO_MEMBER_P (type))
2991 has_pointers = true;
2992
2993 if (CLASS_TYPE_P (type))
2994 {
2995 if (CLASSTYPE_REF_FIELDS_NEED_INIT (type))
2996 SET_CLASSTYPE_REF_FIELDS_NEED_INIT (t, 1);
2997 if (CLASSTYPE_READONLY_FIELDS_NEED_INIT (type))
2998 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t, 1);
2999 }
3000
3001 if (DECL_MUTABLE_P (x) || TYPE_HAS_MUTABLE_P (type))
3002 CLASSTYPE_HAS_MUTABLE (t) = 1;
3003
3004 if (! pod_type_p (type))
3005 /* DR 148 now allows pointers to members (which are POD themselves),
3006 to be allowed in POD structs. */
3007 CLASSTYPE_NON_POD_P (t) = 1;
3008
3009 if (! zero_init_p (type))
3010 CLASSTYPE_NON_ZERO_INIT_P (t) = 1;
3011
3012 /* If any field is const, the structure type is pseudo-const. */
3013 if (CP_TYPE_CONST_P (type))
3014 {
3015 C_TYPE_FIELDS_READONLY (t) = 1;
3016 if (DECL_INITIAL (x) == NULL_TREE)
3017 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t, 1);
3018
3019 /* ARM $12.6.2: [A member initializer list] (or, for an
3020 aggregate, initialization by a brace-enclosed list) is the
3021 only way to initialize nonstatic const and reference
3022 members. */
3023 TYPE_HAS_COMPLEX_ASSIGN_REF (t) = 1;
3024
3025 if (! TYPE_HAS_CONSTRUCTOR (t) && CLASSTYPE_NON_AGGREGATE (t)
3026 && extra_warnings)
3027 warning (OPT_Wextra, "non-static const member %q+#D in class without a constructor", x);
3028 }
3029 /* A field that is pseudo-const makes the structure likewise. */
3030 else if (CLASS_TYPE_P (type))
3031 {
3032 C_TYPE_FIELDS_READONLY (t) |= C_TYPE_FIELDS_READONLY (type);
3033 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t,
3034 CLASSTYPE_READONLY_FIELDS_NEED_INIT (t)
3035 | CLASSTYPE_READONLY_FIELDS_NEED_INIT (type));
3036 }
3037
3038 /* Core issue 80: A nonstatic data member is required to have a
3039 different name from the class iff the class has a
3040 user-defined constructor. */
3041 if (constructor_name_p (DECL_NAME (x), t) && TYPE_HAS_CONSTRUCTOR (t))
3042 pedwarn ("field %q+#D with same name as class", x);
3043
3044 /* We set DECL_C_BIT_FIELD in grokbitfield.
3045 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3046 if (DECL_C_BIT_FIELD (x))
3047 check_bitfield_decl (x);
3048 else
3049 check_field_decl (x, t,
3050 cant_have_const_ctor_p,
3051 no_const_asn_ref_p,
3052 &any_default_members);
3053 }
3054
3055 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3056 it should also define a copy constructor and an assignment operator to
3057 implement the correct copy semantic (deep vs shallow, etc.). As it is
3058 not feasible to check whether the constructors do allocate dynamic memory
3059 and store it within members, we approximate the warning like this:
3060
3061 -- Warn only if there are members which are pointers
3062 -- Warn only if there is a non-trivial constructor (otherwise,
3063 there cannot be memory allocated).
3064 -- Warn only if there is a non-trivial destructor. We assume that the
3065 user at least implemented the cleanup correctly, and a destructor
3066 is needed to free dynamic memory.
3067
3068 This seems enough for practical purposes. */
3069 if (warn_ecpp
3070 && has_pointers
3071 && TYPE_HAS_CONSTRUCTOR (t)
3072 && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
3073 && !(TYPE_HAS_INIT_REF (t) && TYPE_HAS_ASSIGN_REF (t)))
3074 {
3075 warning (OPT_Weffc__, "%q#T has pointer data members", t);
3076
3077 if (! TYPE_HAS_INIT_REF (t))
3078 {
3079 warning (OPT_Weffc__,
3080 " but does not override %<%T(const %T&)%>", t, t);
3081 if (!TYPE_HAS_ASSIGN_REF (t))
3082 warning (OPT_Weffc__, " or %<operator=(const %T&)%>", t);
3083 }
3084 else if (! TYPE_HAS_ASSIGN_REF (t))
3085 warning (OPT_Weffc__,
3086 " but does not override %<operator=(const %T&)%>", t);
3087 }
3088
3089 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3090 if (cant_pack)
3091 TYPE_PACKED (t) = 0;
3092
3093 /* Check anonymous struct/anonymous union fields. */
3094 finish_struct_anon (t);
3095
3096 /* We've built up the list of access declarations in reverse order.
3097 Fix that now. */
3098 *access_decls = nreverse (*access_decls);
3099 }
3100
3101 /* If TYPE is an empty class type, records its OFFSET in the table of
3102 OFFSETS. */
3103
3104 static int
record_subobject_offset(tree type,tree offset,splay_tree offsets)3105 record_subobject_offset (tree type, tree offset, splay_tree offsets)
3106 {
3107 splay_tree_node n;
3108
3109 if (!is_empty_class (type))
3110 return 0;
3111
3112 /* Record the location of this empty object in OFFSETS. */
3113 n = splay_tree_lookup (offsets, (splay_tree_key) offset);
3114 if (!n)
3115 n = splay_tree_insert (offsets,
3116 (splay_tree_key) offset,
3117 (splay_tree_value) NULL_TREE);
3118 n->value = ((splay_tree_value)
3119 tree_cons (NULL_TREE,
3120 type,
3121 (tree) n->value));
3122
3123 return 0;
3124 }
3125
3126 /* Returns nonzero if TYPE is an empty class type and there is
3127 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3128
3129 static int
check_subobject_offset(tree type,tree offset,splay_tree offsets)3130 check_subobject_offset (tree type, tree offset, splay_tree offsets)
3131 {
3132 splay_tree_node n;
3133 tree t;
3134
3135 if (!is_empty_class (type))
3136 return 0;
3137
3138 /* Record the location of this empty object in OFFSETS. */
3139 n = splay_tree_lookup (offsets, (splay_tree_key) offset);
3140 if (!n)
3141 return 0;
3142
3143 for (t = (tree) n->value; t; t = TREE_CHAIN (t))
3144 if (same_type_p (TREE_VALUE (t), type))
3145 return 1;
3146
3147 return 0;
3148 }
3149
3150 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3151 F for every subobject, passing it the type, offset, and table of
3152 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3153 be traversed.
3154
3155 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3156 than MAX_OFFSET will not be walked.
3157
3158 If F returns a nonzero value, the traversal ceases, and that value
3159 is returned. Otherwise, returns zero. */
3160
3161 static int
walk_subobject_offsets(tree type,subobject_offset_fn f,tree offset,splay_tree offsets,tree max_offset,int vbases_p)3162 walk_subobject_offsets (tree type,
3163 subobject_offset_fn f,
3164 tree offset,
3165 splay_tree offsets,
3166 tree max_offset,
3167 int vbases_p)
3168 {
3169 int r = 0;
3170 tree type_binfo = NULL_TREE;
3171
3172 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3173 stop. */
3174 if (max_offset && INT_CST_LT (max_offset, offset))
3175 return 0;
3176
3177 if (type == error_mark_node)
3178 return 0;
3179
3180 if (!TYPE_P (type))
3181 {
3182 if (abi_version_at_least (2))
3183 type_binfo = type;
3184 type = BINFO_TYPE (type);
3185 }
3186
3187 if (CLASS_TYPE_P (type))
3188 {
3189 tree field;
3190 tree binfo;
3191 int i;
3192
3193 /* Avoid recursing into objects that are not interesting. */
3194 if (!CLASSTYPE_CONTAINS_EMPTY_CLASS_P (type))
3195 return 0;
3196
3197 /* Record the location of TYPE. */
3198 r = (*f) (type, offset, offsets);
3199 if (r)
3200 return r;
3201
3202 /* Iterate through the direct base classes of TYPE. */
3203 if (!type_binfo)
3204 type_binfo = TYPE_BINFO (type);
3205 for (i = 0; BINFO_BASE_ITERATE (type_binfo, i, binfo); i++)
3206 {
3207 tree binfo_offset;
3208
3209 if (abi_version_at_least (2)
3210 && BINFO_VIRTUAL_P (binfo))
3211 continue;
3212
3213 if (!vbases_p
3214 && BINFO_VIRTUAL_P (binfo)
3215 && !BINFO_PRIMARY_P (binfo))
3216 continue;
3217
3218 if (!abi_version_at_least (2))
3219 binfo_offset = size_binop (PLUS_EXPR,
3220 offset,
3221 BINFO_OFFSET (binfo));
3222 else
3223 {
3224 tree orig_binfo;
3225 /* We cannot rely on BINFO_OFFSET being set for the base
3226 class yet, but the offsets for direct non-virtual
3227 bases can be calculated by going back to the TYPE. */
3228 orig_binfo = BINFO_BASE_BINFO (TYPE_BINFO (type), i);
3229 binfo_offset = size_binop (PLUS_EXPR,
3230 offset,
3231 BINFO_OFFSET (orig_binfo));
3232 }
3233
3234 r = walk_subobject_offsets (binfo,
3235 f,
3236 binfo_offset,
3237 offsets,
3238 max_offset,
3239 (abi_version_at_least (2)
3240 ? /*vbases_p=*/0 : vbases_p));
3241 if (r)
3242 return r;
3243 }
3244
3245 if (abi_version_at_least (2) && CLASSTYPE_VBASECLASSES (type))
3246 {
3247 unsigned ix;
3248 VEC(tree,gc) *vbases;
3249
3250 /* Iterate through the virtual base classes of TYPE. In G++
3251 3.2, we included virtual bases in the direct base class
3252 loop above, which results in incorrect results; the
3253 correct offsets for virtual bases are only known when
3254 working with the most derived type. */
3255 if (vbases_p)
3256 for (vbases = CLASSTYPE_VBASECLASSES (type), ix = 0;
3257 VEC_iterate (tree, vbases, ix, binfo); ix++)
3258 {
3259 r = walk_subobject_offsets (binfo,
3260 f,
3261 size_binop (PLUS_EXPR,
3262 offset,
3263 BINFO_OFFSET (binfo)),
3264 offsets,
3265 max_offset,
3266 /*vbases_p=*/0);
3267 if (r)
3268 return r;
3269 }
3270 else
3271 {
3272 /* We still have to walk the primary base, if it is
3273 virtual. (If it is non-virtual, then it was walked
3274 above.) */
3275 tree vbase = get_primary_binfo (type_binfo);
3276
3277 if (vbase && BINFO_VIRTUAL_P (vbase)
3278 && BINFO_PRIMARY_P (vbase)
3279 && BINFO_INHERITANCE_CHAIN (vbase) == type_binfo)
3280 {
3281 r = (walk_subobject_offsets
3282 (vbase, f, offset,
3283 offsets, max_offset, /*vbases_p=*/0));
3284 if (r)
3285 return r;
3286 }
3287 }
3288 }
3289
3290 /* Iterate through the fields of TYPE. */
3291 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3292 if (TREE_CODE (field) == FIELD_DECL && !DECL_ARTIFICIAL (field))
3293 {
3294 tree field_offset;
3295
3296 if (abi_version_at_least (2))
3297 field_offset = byte_position (field);
3298 else
3299 /* In G++ 3.2, DECL_FIELD_OFFSET was used. */
3300 field_offset = DECL_FIELD_OFFSET (field);
3301
3302 r = walk_subobject_offsets (TREE_TYPE (field),
3303 f,
3304 size_binop (PLUS_EXPR,
3305 offset,
3306 field_offset),
3307 offsets,
3308 max_offset,
3309 /*vbases_p=*/1);
3310 if (r)
3311 return r;
3312 }
3313 }
3314 else if (TREE_CODE (type) == ARRAY_TYPE)
3315 {
3316 tree element_type = strip_array_types (type);
3317 tree domain = TYPE_DOMAIN (type);
3318 tree index;
3319
3320 /* Avoid recursing into objects that are not interesting. */
3321 if (!CLASS_TYPE_P (element_type)
3322 || !CLASSTYPE_CONTAINS_EMPTY_CLASS_P (element_type))
3323 return 0;
3324
3325 /* Step through each of the elements in the array. */
3326 for (index = size_zero_node;
3327 /* G++ 3.2 had an off-by-one error here. */
3328 (abi_version_at_least (2)
3329 ? !INT_CST_LT (TYPE_MAX_VALUE (domain), index)
3330 : INT_CST_LT (index, TYPE_MAX_VALUE (domain)));
3331 index = size_binop (PLUS_EXPR, index, size_one_node))
3332 {
3333 r = walk_subobject_offsets (TREE_TYPE (type),
3334 f,
3335 offset,
3336 offsets,
3337 max_offset,
3338 /*vbases_p=*/1);
3339 if (r)
3340 return r;
3341 offset = size_binop (PLUS_EXPR, offset,
3342 TYPE_SIZE_UNIT (TREE_TYPE (type)));
3343 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3344 there's no point in iterating through the remaining
3345 elements of the array. */
3346 if (max_offset && INT_CST_LT (max_offset, offset))
3347 break;
3348 }
3349 }
3350
3351 return 0;
3352 }
3353
3354 /* Record all of the empty subobjects of TYPE (either a type or a
3355 binfo). If IS_DATA_MEMBER is true, then a non-static data member
3356 is being placed at OFFSET; otherwise, it is a base class that is
3357 being placed at OFFSET. */
3358
3359 static void
record_subobject_offsets(tree type,tree offset,splay_tree offsets,bool is_data_member)3360 record_subobject_offsets (tree type,
3361 tree offset,
3362 splay_tree offsets,
3363 bool is_data_member)
3364 {
3365 tree max_offset;
3366 /* If recording subobjects for a non-static data member or a
3367 non-empty base class , we do not need to record offsets beyond
3368 the size of the biggest empty class. Additional data members
3369 will go at the end of the class. Additional base classes will go
3370 either at offset zero (if empty, in which case they cannot
3371 overlap with offsets past the size of the biggest empty class) or
3372 at the end of the class.
3373
3374 However, if we are placing an empty base class, then we must record
3375 all offsets, as either the empty class is at offset zero (where
3376 other empty classes might later be placed) or at the end of the
3377 class (where other objects might then be placed, so other empty
3378 subobjects might later overlap). */
3379 if (is_data_member
3380 || !is_empty_class (BINFO_TYPE (type)))
3381 max_offset = sizeof_biggest_empty_class;
3382 else
3383 max_offset = NULL_TREE;
3384 walk_subobject_offsets (type, record_subobject_offset, offset,
3385 offsets, max_offset, is_data_member);
3386 }
3387
3388 /* Returns nonzero if any of the empty subobjects of TYPE (located at
3389 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
3390 virtual bases of TYPE are examined. */
3391
3392 static int
layout_conflict_p(tree type,tree offset,splay_tree offsets,int vbases_p)3393 layout_conflict_p (tree type,
3394 tree offset,
3395 splay_tree offsets,
3396 int vbases_p)
3397 {
3398 splay_tree_node max_node;
3399
3400 /* Get the node in OFFSETS that indicates the maximum offset where
3401 an empty subobject is located. */
3402 max_node = splay_tree_max (offsets);
3403 /* If there aren't any empty subobjects, then there's no point in
3404 performing this check. */
3405 if (!max_node)
3406 return 0;
3407
3408 return walk_subobject_offsets (type, check_subobject_offset, offset,
3409 offsets, (tree) (max_node->key),
3410 vbases_p);
3411 }
3412
3413 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
3414 non-static data member of the type indicated by RLI. BINFO is the
3415 binfo corresponding to the base subobject, OFFSETS maps offsets to
3416 types already located at those offsets. This function determines
3417 the position of the DECL. */
3418
3419 static void
layout_nonempty_base_or_field(record_layout_info rli,tree decl,tree binfo,splay_tree offsets)3420 layout_nonempty_base_or_field (record_layout_info rli,
3421 tree decl,
3422 tree binfo,
3423 splay_tree offsets)
3424 {
3425 tree offset = NULL_TREE;
3426 bool field_p;
3427 tree type;
3428
3429 if (binfo)
3430 {
3431 /* For the purposes of determining layout conflicts, we want to
3432 use the class type of BINFO; TREE_TYPE (DECL) will be the
3433 CLASSTYPE_AS_BASE version, which does not contain entries for
3434 zero-sized bases. */
3435 type = TREE_TYPE (binfo);
3436 field_p = false;
3437 }
3438 else
3439 {
3440 type = TREE_TYPE (decl);
3441 field_p = true;
3442 }
3443
3444 /* Try to place the field. It may take more than one try if we have
3445 a hard time placing the field without putting two objects of the
3446 same type at the same address. */
3447 while (1)
3448 {
3449 struct record_layout_info_s old_rli = *rli;
3450
3451 /* Place this field. */
3452 place_field (rli, decl);
3453 offset = byte_position (decl);
3454
3455 /* We have to check to see whether or not there is already
3456 something of the same type at the offset we're about to use.
3457 For example, consider:
3458
3459 struct S {};
3460 struct T : public S { int i; };
3461 struct U : public S, public T {};
3462
3463 Here, we put S at offset zero in U. Then, we can't put T at
3464 offset zero -- its S component would be at the same address
3465 as the S we already allocated. So, we have to skip ahead.
3466 Since all data members, including those whose type is an
3467 empty class, have nonzero size, any overlap can happen only
3468 with a direct or indirect base-class -- it can't happen with
3469 a data member. */
3470 /* In a union, overlap is permitted; all members are placed at
3471 offset zero. */
3472 if (TREE_CODE (rli->t) == UNION_TYPE)
3473 break;
3474 /* G++ 3.2 did not check for overlaps when placing a non-empty
3475 virtual base. */
3476 if (!abi_version_at_least (2) && binfo && BINFO_VIRTUAL_P (binfo))
3477 break;
3478 if (layout_conflict_p (field_p ? type : binfo, offset,
3479 offsets, field_p))
3480 {
3481 /* Strip off the size allocated to this field. That puts us
3482 at the first place we could have put the field with
3483 proper alignment. */
3484 *rli = old_rli;
3485
3486 /* Bump up by the alignment required for the type. */
3487 rli->bitpos
3488 = size_binop (PLUS_EXPR, rli->bitpos,
3489 bitsize_int (binfo
3490 ? CLASSTYPE_ALIGN (type)
3491 : TYPE_ALIGN (type)));
3492 normalize_rli (rli);
3493 }
3494 else
3495 /* There was no conflict. We're done laying out this field. */
3496 break;
3497 }
3498
3499 /* Now that we know where it will be placed, update its
3500 BINFO_OFFSET. */
3501 if (binfo && CLASS_TYPE_P (BINFO_TYPE (binfo)))
3502 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
3503 this point because their BINFO_OFFSET is copied from another
3504 hierarchy. Therefore, we may not need to add the entire
3505 OFFSET. */
3506 propagate_binfo_offsets (binfo,
3507 size_diffop (convert (ssizetype, offset),
3508 convert (ssizetype,
3509 BINFO_OFFSET (binfo))));
3510 }
3511
3512 /* Returns true if TYPE is empty and OFFSET is nonzero. */
3513
3514 static int
empty_base_at_nonzero_offset_p(tree type,tree offset,splay_tree offsets ATTRIBUTE_UNUSED)3515 empty_base_at_nonzero_offset_p (tree type,
3516 tree offset,
3517 splay_tree offsets ATTRIBUTE_UNUSED)
3518 {
3519 return is_empty_class (type) && !integer_zerop (offset);
3520 }
3521
3522 /* Layout the empty base BINFO. EOC indicates the byte currently just
3523 past the end of the class, and should be correctly aligned for a
3524 class of the type indicated by BINFO; OFFSETS gives the offsets of
3525 the empty bases allocated so far. T is the most derived
3526 type. Return nonzero iff we added it at the end. */
3527
3528 static bool
layout_empty_base(tree binfo,tree eoc,splay_tree offsets)3529 layout_empty_base (tree binfo, tree eoc, splay_tree offsets)
3530 {
3531 tree alignment;
3532 tree basetype = BINFO_TYPE (binfo);
3533 bool atend = false;
3534
3535 /* This routine should only be used for empty classes. */
3536 gcc_assert (is_empty_class (basetype));
3537 alignment = ssize_int (CLASSTYPE_ALIGN_UNIT (basetype));
3538
3539 if (!integer_zerop (BINFO_OFFSET (binfo)))
3540 {
3541 if (abi_version_at_least (2))
3542 propagate_binfo_offsets
3543 (binfo, size_diffop (size_zero_node, BINFO_OFFSET (binfo)));
3544 else
3545 warning (OPT_Wabi,
3546 "offset of empty base %qT may not be ABI-compliant and may"
3547 "change in a future version of GCC",
3548 BINFO_TYPE (binfo));
3549 }
3550
3551 /* This is an empty base class. We first try to put it at offset
3552 zero. */
3553 if (layout_conflict_p (binfo,
3554 BINFO_OFFSET (binfo),
3555 offsets,
3556 /*vbases_p=*/0))
3557 {
3558 /* That didn't work. Now, we move forward from the next
3559 available spot in the class. */
3560 atend = true;
3561 propagate_binfo_offsets (binfo, convert (ssizetype, eoc));
3562 while (1)
3563 {
3564 if (!layout_conflict_p (binfo,
3565 BINFO_OFFSET (binfo),
3566 offsets,
3567 /*vbases_p=*/0))
3568 /* We finally found a spot where there's no overlap. */
3569 break;
3570
3571 /* There's overlap here, too. Bump along to the next spot. */
3572 propagate_binfo_offsets (binfo, alignment);
3573 }
3574 }
3575 return atend;
3576 }
3577
3578 /* Layout the base given by BINFO in the class indicated by RLI.
3579 *BASE_ALIGN is a running maximum of the alignments of
3580 any base class. OFFSETS gives the location of empty base
3581 subobjects. T is the most derived type. Return nonzero if the new
3582 object cannot be nearly-empty. A new FIELD_DECL is inserted at
3583 *NEXT_FIELD, unless BINFO is for an empty base class.
3584
3585 Returns the location at which the next field should be inserted. */
3586
3587 static tree *
build_base_field(record_layout_info rli,tree binfo,splay_tree offsets,tree * next_field)3588 build_base_field (record_layout_info rli, tree binfo,
3589 splay_tree offsets, tree *next_field)
3590 {
3591 tree t = rli->t;
3592 tree basetype = BINFO_TYPE (binfo);
3593
3594 if (!COMPLETE_TYPE_P (basetype))
3595 /* This error is now reported in xref_tag, thus giving better
3596 location information. */
3597 return next_field;
3598
3599 /* Place the base class. */
3600 if (!is_empty_class (basetype))
3601 {
3602 tree decl;
3603
3604 /* The containing class is non-empty because it has a non-empty
3605 base class. */
3606 CLASSTYPE_EMPTY_P (t) = 0;
3607
3608 /* Create the FIELD_DECL. */
3609 decl = build_decl (FIELD_DECL, NULL_TREE, CLASSTYPE_AS_BASE (basetype));
3610 DECL_ARTIFICIAL (decl) = 1;
3611 DECL_IGNORED_P (decl) = 1;
3612 DECL_FIELD_CONTEXT (decl) = t;
3613 DECL_SIZE (decl) = CLASSTYPE_SIZE (basetype);
3614 DECL_SIZE_UNIT (decl) = CLASSTYPE_SIZE_UNIT (basetype);
3615 DECL_ALIGN (decl) = CLASSTYPE_ALIGN (basetype);
3616 DECL_USER_ALIGN (decl) = CLASSTYPE_USER_ALIGN (basetype);
3617 DECL_MODE (decl) = TYPE_MODE (basetype);
3618 DECL_FIELD_IS_BASE (decl) = 1;
3619
3620 /* Try to place the field. It may take more than one try if we
3621 have a hard time placing the field without putting two
3622 objects of the same type at the same address. */
3623 layout_nonempty_base_or_field (rli, decl, binfo, offsets);
3624 /* Add the new FIELD_DECL to the list of fields for T. */
3625 TREE_CHAIN (decl) = *next_field;
3626 *next_field = decl;
3627 next_field = &TREE_CHAIN (decl);
3628 }
3629 else
3630 {
3631 tree eoc;
3632 bool atend;
3633
3634 /* On some platforms (ARM), even empty classes will not be
3635 byte-aligned. */
3636 eoc = round_up (rli_size_unit_so_far (rli),
3637 CLASSTYPE_ALIGN_UNIT (basetype));
3638 atend = layout_empty_base (binfo, eoc, offsets);
3639 /* A nearly-empty class "has no proper base class that is empty,
3640 not morally virtual, and at an offset other than zero." */
3641 if (!BINFO_VIRTUAL_P (binfo) && CLASSTYPE_NEARLY_EMPTY_P (t))
3642 {
3643 if (atend)
3644 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
3645 /* The check above (used in G++ 3.2) is insufficient because
3646 an empty class placed at offset zero might itself have an
3647 empty base at a nonzero offset. */
3648 else if (walk_subobject_offsets (basetype,
3649 empty_base_at_nonzero_offset_p,
3650 size_zero_node,
3651 /*offsets=*/NULL,
3652 /*max_offset=*/NULL_TREE,
3653 /*vbases_p=*/true))
3654 {
3655 if (abi_version_at_least (2))
3656 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
3657 else
3658 warning (OPT_Wabi,
3659 "class %qT will be considered nearly empty in a "
3660 "future version of GCC", t);
3661 }
3662 }
3663
3664 /* We do not create a FIELD_DECL for empty base classes because
3665 it might overlap some other field. We want to be able to
3666 create CONSTRUCTORs for the class by iterating over the
3667 FIELD_DECLs, and the back end does not handle overlapping
3668 FIELD_DECLs. */
3669
3670 /* An empty virtual base causes a class to be non-empty
3671 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
3672 here because that was already done when the virtual table
3673 pointer was created. */
3674 }
3675
3676 /* Record the offsets of BINFO and its base subobjects. */
3677 record_subobject_offsets (binfo,
3678 BINFO_OFFSET (binfo),
3679 offsets,
3680 /*is_data_member=*/false);
3681
3682 return next_field;
3683 }
3684
3685 /* Layout all of the non-virtual base classes. Record empty
3686 subobjects in OFFSETS. T is the most derived type. Return nonzero
3687 if the type cannot be nearly empty. The fields created
3688 corresponding to the base classes will be inserted at
3689 *NEXT_FIELD. */
3690
3691 static void
build_base_fields(record_layout_info rli,splay_tree offsets,tree * next_field)3692 build_base_fields (record_layout_info rli,
3693 splay_tree offsets, tree *next_field)
3694 {
3695 /* Chain to hold all the new FIELD_DECLs which stand in for base class
3696 subobjects. */
3697 tree t = rli->t;
3698 int n_baseclasses = BINFO_N_BASE_BINFOS (TYPE_BINFO (t));
3699 int i;
3700
3701 /* The primary base class is always allocated first. */
3702 if (CLASSTYPE_HAS_PRIMARY_BASE_P (t))
3703 next_field = build_base_field (rli, CLASSTYPE_PRIMARY_BINFO (t),
3704 offsets, next_field);
3705
3706 /* Now allocate the rest of the bases. */
3707 for (i = 0; i < n_baseclasses; ++i)
3708 {
3709 tree base_binfo;
3710
3711 base_binfo = BINFO_BASE_BINFO (TYPE_BINFO (t), i);
3712
3713 /* The primary base was already allocated above, so we don't
3714 need to allocate it again here. */
3715 if (base_binfo == CLASSTYPE_PRIMARY_BINFO (t))
3716 continue;
3717
3718 /* Virtual bases are added at the end (a primary virtual base
3719 will have already been added). */
3720 if (BINFO_VIRTUAL_P (base_binfo))
3721 continue;
3722
3723 next_field = build_base_field (rli, base_binfo,
3724 offsets, next_field);
3725 }
3726 }
3727
3728 /* Go through the TYPE_METHODS of T issuing any appropriate
3729 diagnostics, figuring out which methods override which other
3730 methods, and so forth. */
3731
3732 static void
check_methods(tree t)3733 check_methods (tree t)
3734 {
3735 tree x;
3736
3737 for (x = TYPE_METHODS (t); x; x = TREE_CHAIN (x))
3738 {
3739 check_for_override (x, t);
3740 if (DECL_PURE_VIRTUAL_P (x) && ! DECL_VINDEX (x))
3741 error ("initializer specified for non-virtual method %q+D", x);
3742 /* The name of the field is the original field name
3743 Save this in auxiliary field for later overloading. */
3744 if (DECL_VINDEX (x))
3745 {
3746 TYPE_POLYMORPHIC_P (t) = 1;
3747 if (DECL_PURE_VIRTUAL_P (x))
3748 VEC_safe_push (tree, gc, CLASSTYPE_PURE_VIRTUALS (t), x);
3749 }
3750 /* All user-declared destructors are non-trivial. */
3751 if (DECL_DESTRUCTOR_P (x))
3752 /* APPLE LOCAL begin omit calls to empty destructors 5559195 */
3753 {
3754 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t) = 1;
3755
3756 /* Conservatively assume that destructor body is nontrivial. Will
3757 be unmarked during parsing of function body if it happens to be
3758 trivial. */
3759 CLASSTYPE_HAS_NONTRIVIAL_DESTRUCTOR_BODY (t) = 1;
3760 }
3761 /* APPLE LOCAL end omit calls to empty destructors 5559195 */
3762 }
3763 }
3764
3765 /* FN is a constructor or destructor. Clone the declaration to create
3766 a specialized in-charge or not-in-charge version, as indicated by
3767 NAME. */
3768
3769 static tree
build_clone(tree fn,tree name)3770 build_clone (tree fn, tree name)
3771 {
3772 tree parms;
3773 tree clone;
3774
3775 /* Copy the function. */
3776 clone = copy_decl (fn);
3777 /* Remember where this function came from. */
3778 DECL_CLONED_FUNCTION (clone) = fn;
3779 DECL_ABSTRACT_ORIGIN (clone) = fn;
3780 /* Reset the function name. */
3781 DECL_NAME (clone) = name;
3782 SET_DECL_ASSEMBLER_NAME (clone, NULL_TREE);
3783 /* There's no pending inline data for this function. */
3784 DECL_PENDING_INLINE_INFO (clone) = NULL;
3785 DECL_PENDING_INLINE_P (clone) = 0;
3786 /* And it hasn't yet been deferred. */
3787 DECL_DEFERRED_FN (clone) = 0;
3788
3789 /* The base-class destructor is not virtual. */
3790 if (name == base_dtor_identifier)
3791 {
3792 DECL_VIRTUAL_P (clone) = 0;
3793 if (TREE_CODE (clone) != TEMPLATE_DECL)
3794 DECL_VINDEX (clone) = NULL_TREE;
3795 }
3796
3797 /* If there was an in-charge parameter, drop it from the function
3798 type. */
3799 if (DECL_HAS_IN_CHARGE_PARM_P (clone))
3800 {
3801 tree basetype;
3802 tree parmtypes;
3803 tree exceptions;
3804
3805 exceptions = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (clone));
3806 basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (clone));
3807 parmtypes = TYPE_ARG_TYPES (TREE_TYPE (clone));
3808 /* Skip the `this' parameter. */
3809 parmtypes = TREE_CHAIN (parmtypes);
3810 /* Skip the in-charge parameter. */
3811 parmtypes = TREE_CHAIN (parmtypes);
3812 /* And the VTT parm, in a complete [cd]tor. */
3813 if (DECL_HAS_VTT_PARM_P (fn)
3814 && ! DECL_NEEDS_VTT_PARM_P (clone))
3815 parmtypes = TREE_CHAIN (parmtypes);
3816 /* If this is subobject constructor or destructor, add the vtt
3817 parameter. */
3818 TREE_TYPE (clone)
3819 = build_method_type_directly (basetype,
3820 TREE_TYPE (TREE_TYPE (clone)),
3821 parmtypes);
3822 if (exceptions)
3823 TREE_TYPE (clone) = build_exception_variant (TREE_TYPE (clone),
3824 exceptions);
3825 TREE_TYPE (clone)
3826 = cp_build_type_attribute_variant (TREE_TYPE (clone),
3827 TYPE_ATTRIBUTES (TREE_TYPE (fn)));
3828 }
3829
3830 /* Copy the function parameters. But, DECL_ARGUMENTS on a TEMPLATE_DECL
3831 aren't function parameters; those are the template parameters. */
3832 if (TREE_CODE (clone) != TEMPLATE_DECL)
3833 {
3834 DECL_ARGUMENTS (clone) = copy_list (DECL_ARGUMENTS (clone));
3835 /* Remove the in-charge parameter. */
3836 if (DECL_HAS_IN_CHARGE_PARM_P (clone))
3837 {
3838 TREE_CHAIN (DECL_ARGUMENTS (clone))
3839 = TREE_CHAIN (TREE_CHAIN (DECL_ARGUMENTS (clone)));
3840 DECL_HAS_IN_CHARGE_PARM_P (clone) = 0;
3841 }
3842 /* And the VTT parm, in a complete [cd]tor. */
3843 if (DECL_HAS_VTT_PARM_P (fn))
3844 {
3845 if (DECL_NEEDS_VTT_PARM_P (clone))
3846 DECL_HAS_VTT_PARM_P (clone) = 1;
3847 else
3848 {
3849 TREE_CHAIN (DECL_ARGUMENTS (clone))
3850 = TREE_CHAIN (TREE_CHAIN (DECL_ARGUMENTS (clone)));
3851 DECL_HAS_VTT_PARM_P (clone) = 0;
3852 }
3853 }
3854
3855 for (parms = DECL_ARGUMENTS (clone); parms; parms = TREE_CHAIN (parms))
3856 {
3857 DECL_CONTEXT (parms) = clone;
3858 cxx_dup_lang_specific_decl (parms);
3859 }
3860 }
3861
3862 /* Create the RTL for this function. */
3863 SET_DECL_RTL (clone, NULL_RTX);
3864 rest_of_decl_compilation (clone, /*top_level=*/1, at_eof);
3865
3866 /* Make it easy to find the CLONE given the FN. */
3867 TREE_CHAIN (clone) = TREE_CHAIN (fn);
3868 TREE_CHAIN (fn) = clone;
3869
3870 /* If this is a template, handle the DECL_TEMPLATE_RESULT as well. */
3871 if (TREE_CODE (clone) == TEMPLATE_DECL)
3872 {
3873 tree result;
3874
3875 DECL_TEMPLATE_RESULT (clone)
3876 = build_clone (DECL_TEMPLATE_RESULT (clone), name);
3877 result = DECL_TEMPLATE_RESULT (clone);
3878 DECL_TEMPLATE_INFO (result) = copy_node (DECL_TEMPLATE_INFO (result));
3879 DECL_TI_TEMPLATE (result) = clone;
3880 }
3881 else if (pch_file)
3882 note_decl_for_pch (clone);
3883
3884 return clone;
3885 }
3886
3887 /* Produce declarations for all appropriate clones of FN. If
3888 UPDATE_METHOD_VEC_P is nonzero, the clones are added to the
3889 CLASTYPE_METHOD_VEC as well. */
3890
3891 void
clone_function_decl(tree fn,int update_method_vec_p)3892 clone_function_decl (tree fn, int update_method_vec_p)
3893 {
3894 tree clone;
3895
3896 /* Avoid inappropriate cloning. */
3897 if (TREE_CHAIN (fn)
3898 && DECL_CLONED_FUNCTION (TREE_CHAIN (fn)))
3899 return;
3900
3901 if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn))
3902 {
3903 /* For each constructor, we need two variants: an in-charge version
3904 and a not-in-charge version. */
3905 clone = build_clone (fn, complete_ctor_identifier);
3906 if (update_method_vec_p)
3907 add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3908 clone = build_clone (fn, base_ctor_identifier);
3909 if (update_method_vec_p)
3910 add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3911 }
3912 else
3913 {
3914 gcc_assert (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn));
3915
3916 /* For each destructor, we need three variants: an in-charge
3917 version, a not-in-charge version, and an in-charge deleting
3918 version. We clone the deleting version first because that
3919 means it will go second on the TYPE_METHODS list -- and that
3920 corresponds to the correct layout order in the virtual
3921 function table.
3922
3923 For a non-virtual destructor, we do not build a deleting
3924 destructor. */
3925 if (DECL_VIRTUAL_P (fn))
3926 {
3927 clone = build_clone (fn, deleting_dtor_identifier);
3928 if (update_method_vec_p)
3929 add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3930 }
3931 clone = build_clone (fn, complete_dtor_identifier);
3932 if (update_method_vec_p)
3933 add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3934 clone = build_clone (fn, base_dtor_identifier);
3935 if (update_method_vec_p)
3936 add_method (DECL_CONTEXT (clone), clone, NULL_TREE);
3937 }
3938
3939 /* Note that this is an abstract function that is never emitted. */
3940 DECL_ABSTRACT (fn) = 1;
3941 }
3942
3943 /* DECL is an in charge constructor, which is being defined. This will
3944 have had an in class declaration, from whence clones were
3945 declared. An out-of-class definition can specify additional default
3946 arguments. As it is the clones that are involved in overload
3947 resolution, we must propagate the information from the DECL to its
3948 clones. */
3949
3950 void
adjust_clone_args(tree decl)3951 adjust_clone_args (tree decl)
3952 {
3953 tree clone;
3954
3955 for (clone = TREE_CHAIN (decl); clone && DECL_CLONED_FUNCTION (clone);
3956 clone = TREE_CHAIN (clone))
3957 {
3958 tree orig_clone_parms = TYPE_ARG_TYPES (TREE_TYPE (clone));
3959 tree orig_decl_parms = TYPE_ARG_TYPES (TREE_TYPE (decl));
3960 tree decl_parms, clone_parms;
3961
3962 clone_parms = orig_clone_parms;
3963
3964 /* Skip the 'this' parameter. */
3965 orig_clone_parms = TREE_CHAIN (orig_clone_parms);
3966 orig_decl_parms = TREE_CHAIN (orig_decl_parms);
3967
3968 if (DECL_HAS_IN_CHARGE_PARM_P (decl))
3969 orig_decl_parms = TREE_CHAIN (orig_decl_parms);
3970 if (DECL_HAS_VTT_PARM_P (decl))
3971 orig_decl_parms = TREE_CHAIN (orig_decl_parms);
3972
3973 clone_parms = orig_clone_parms;
3974 if (DECL_HAS_VTT_PARM_P (clone))
3975 clone_parms = TREE_CHAIN (clone_parms);
3976
3977 for (decl_parms = orig_decl_parms; decl_parms;
3978 decl_parms = TREE_CHAIN (decl_parms),
3979 clone_parms = TREE_CHAIN (clone_parms))
3980 {
3981 gcc_assert (same_type_p (TREE_TYPE (decl_parms),
3982 TREE_TYPE (clone_parms)));
3983
3984 if (TREE_PURPOSE (decl_parms) && !TREE_PURPOSE (clone_parms))
3985 {
3986 /* A default parameter has been added. Adjust the
3987 clone's parameters. */
3988 tree exceptions = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (clone));
3989 tree basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (clone));
3990 tree type;
3991
3992 clone_parms = orig_decl_parms;
3993
3994 if (DECL_HAS_VTT_PARM_P (clone))
3995 {
3996 clone_parms = tree_cons (TREE_PURPOSE (orig_clone_parms),
3997 TREE_VALUE (orig_clone_parms),
3998 clone_parms);
3999 TREE_TYPE (clone_parms) = TREE_TYPE (orig_clone_parms);
4000 }
4001 type = build_method_type_directly (basetype,
4002 TREE_TYPE (TREE_TYPE (clone)),
4003 clone_parms);
4004 if (exceptions)
4005 type = build_exception_variant (type, exceptions);
4006 TREE_TYPE (clone) = type;
4007
4008 clone_parms = NULL_TREE;
4009 break;
4010 }
4011 }
4012 gcc_assert (!clone_parms);
4013 }
4014 }
4015
4016 /* For each of the constructors and destructors in T, create an
4017 in-charge and not-in-charge variant. */
4018
4019 static void
clone_constructors_and_destructors(tree t)4020 clone_constructors_and_destructors (tree t)
4021 {
4022 tree fns;
4023
4024 /* If for some reason we don't have a CLASSTYPE_METHOD_VEC, we bail
4025 out now. */
4026 if (!CLASSTYPE_METHOD_VEC (t))
4027 return;
4028
4029 for (fns = CLASSTYPE_CONSTRUCTORS (t); fns; fns = OVL_NEXT (fns))
4030 clone_function_decl (OVL_CURRENT (fns), /*update_method_vec_p=*/1);
4031 for (fns = CLASSTYPE_DESTRUCTORS (t); fns; fns = OVL_NEXT (fns))
4032 clone_function_decl (OVL_CURRENT (fns), /*update_method_vec_p=*/1);
4033 }
4034
4035 /* Remove all zero-width bit-fields from T. */
4036
4037 static void
remove_zero_width_bit_fields(tree t)4038 remove_zero_width_bit_fields (tree t)
4039 {
4040 tree *fieldsp;
4041
4042 fieldsp = &TYPE_FIELDS (t);
4043 while (*fieldsp)
4044 {
4045 if (TREE_CODE (*fieldsp) == FIELD_DECL
4046 && DECL_C_BIT_FIELD (*fieldsp)
4047 && DECL_INITIAL (*fieldsp))
4048 *fieldsp = TREE_CHAIN (*fieldsp);
4049 else
4050 fieldsp = &TREE_CHAIN (*fieldsp);
4051 }
4052 }
4053
4054 /* Returns TRUE iff we need a cookie when dynamically allocating an
4055 array whose elements have the indicated class TYPE. */
4056
4057 static bool
type_requires_array_cookie(tree type)4058 type_requires_array_cookie (tree type)
4059 {
4060 tree fns;
4061 bool has_two_argument_delete_p = false;
4062
4063 gcc_assert (CLASS_TYPE_P (type));
4064
4065 /* If there's a non-trivial destructor, we need a cookie. In order
4066 to iterate through the array calling the destructor for each
4067 element, we'll have to know how many elements there are. */
4068 if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
4069 return true;
4070
4071 /* If the usual deallocation function is a two-argument whose second
4072 argument is of type `size_t', then we have to pass the size of
4073 the array to the deallocation function, so we will need to store
4074 a cookie. */
4075 fns = lookup_fnfields (TYPE_BINFO (type),
4076 ansi_opname (VEC_DELETE_EXPR),
4077 /*protect=*/0);
4078 /* If there are no `operator []' members, or the lookup is
4079 ambiguous, then we don't need a cookie. */
4080 if (!fns || fns == error_mark_node)
4081 return false;
4082 /* Loop through all of the functions. */
4083 for (fns = BASELINK_FUNCTIONS (fns); fns; fns = OVL_NEXT (fns))
4084 {
4085 tree fn;
4086 tree second_parm;
4087
4088 /* Select the current function. */
4089 fn = OVL_CURRENT (fns);
4090 /* See if this function is a one-argument delete function. If
4091 it is, then it will be the usual deallocation function. */
4092 second_parm = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fn)));
4093 if (second_parm == void_list_node)
4094 return false;
4095 /* Otherwise, if we have a two-argument function and the second
4096 argument is `size_t', it will be the usual deallocation
4097 function -- unless there is one-argument function, too. */
4098 if (TREE_CHAIN (second_parm) == void_list_node
4099 && same_type_p (TREE_VALUE (second_parm), sizetype))
4100 has_two_argument_delete_p = true;
4101 }
4102
4103 return has_two_argument_delete_p;
4104 }
4105
4106 /* Check the validity of the bases and members declared in T. Add any
4107 implicitly-generated functions (like copy-constructors and
4108 assignment operators). Compute various flag bits (like
4109 CLASSTYPE_NON_POD_T) for T. This routine works purely at the C++
4110 level: i.e., independently of the ABI in use. */
4111
4112 static void
check_bases_and_members(tree t)4113 check_bases_and_members (tree t)
4114 {
4115 /* Nonzero if the implicitly generated copy constructor should take
4116 a non-const reference argument. */
4117 int cant_have_const_ctor;
4118 /* Nonzero if the implicitly generated assignment operator
4119 should take a non-const reference argument. */
4120 int no_const_asn_ref;
4121 tree access_decls;
4122
4123 /* By default, we use const reference arguments and generate default
4124 constructors. */
4125 cant_have_const_ctor = 0;
4126 no_const_asn_ref = 0;
4127
4128 /* Check all the base-classes. */
4129 check_bases (t, &cant_have_const_ctor,
4130 &no_const_asn_ref);
4131
4132 /* Check all the method declarations. */
4133 check_methods (t);
4134
4135 /* Check all the data member declarations. We cannot call
4136 check_field_decls until we have called check_bases check_methods,
4137 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
4138 being set appropriately. */
4139 check_field_decls (t, &access_decls,
4140 &cant_have_const_ctor,
4141 &no_const_asn_ref);
4142
4143 /* A nearly-empty class has to be vptr-containing; a nearly empty
4144 class contains just a vptr. */
4145 if (!TYPE_CONTAINS_VPTR_P (t))
4146 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
4147
4148 /* Do some bookkeeping that will guide the generation of implicitly
4149 declared member functions. */
4150 TYPE_HAS_COMPLEX_INIT_REF (t)
4151 |= (TYPE_HAS_INIT_REF (t) || TYPE_CONTAINS_VPTR_P (t));
4152 TYPE_NEEDS_CONSTRUCTING (t)
4153 |= (TYPE_HAS_CONSTRUCTOR (t) || TYPE_CONTAINS_VPTR_P (t));
4154 CLASSTYPE_NON_AGGREGATE (t)
4155 |= (TYPE_HAS_CONSTRUCTOR (t) || TYPE_POLYMORPHIC_P (t));
4156 CLASSTYPE_NON_POD_P (t)
4157 |= (CLASSTYPE_NON_AGGREGATE (t)
4158 || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
4159 || TYPE_HAS_ASSIGN_REF (t));
4160 TYPE_HAS_COMPLEX_ASSIGN_REF (t)
4161 |= TYPE_HAS_ASSIGN_REF (t) || TYPE_CONTAINS_VPTR_P (t);
4162
4163 /* Synthesize any needed methods. */
4164 add_implicitly_declared_members (t,
4165 cant_have_const_ctor,
4166 no_const_asn_ref);
4167
4168 /* Create the in-charge and not-in-charge variants of constructors
4169 and destructors. */
4170 clone_constructors_and_destructors (t);
4171
4172 /* Process the using-declarations. */
4173 for (; access_decls; access_decls = TREE_CHAIN (access_decls))
4174 handle_using_decl (TREE_VALUE (access_decls), t);
4175
4176 /* Build and sort the CLASSTYPE_METHOD_VEC. */
4177 finish_struct_methods (t);
4178
4179 /* Figure out whether or not we will need a cookie when dynamically
4180 allocating an array of this type. */
4181 TYPE_LANG_SPECIFIC (t)->u.c.vec_new_uses_cookie
4182 = type_requires_array_cookie (t);
4183 }
4184
4185 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
4186 accordingly. If a new vfield was created (because T doesn't have a
4187 primary base class), then the newly created field is returned. It
4188 is not added to the TYPE_FIELDS list; it is the caller's
4189 responsibility to do that. Accumulate declared virtual functions
4190 on VIRTUALS_P. */
4191
4192 static tree
create_vtable_ptr(tree t,tree * virtuals_p)4193 create_vtable_ptr (tree t, tree* virtuals_p)
4194 {
4195 tree fn;
4196
4197 /* Collect the virtual functions declared in T. */
4198 for (fn = TYPE_METHODS (t); fn; fn = TREE_CHAIN (fn))
4199 if (DECL_VINDEX (fn) && !DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn)
4200 && TREE_CODE (DECL_VINDEX (fn)) != INTEGER_CST)
4201 {
4202 tree new_virtual = make_node (TREE_LIST);
4203
4204 BV_FN (new_virtual) = fn;
4205 BV_DELTA (new_virtual) = integer_zero_node;
4206 BV_VCALL_INDEX (new_virtual) = NULL_TREE;
4207
4208 TREE_CHAIN (new_virtual) = *virtuals_p;
4209 *virtuals_p = new_virtual;
4210 }
4211
4212 /* If we couldn't find an appropriate base class, create a new field
4213 here. Even if there weren't any new virtual functions, we might need a
4214 new virtual function table if we're supposed to include vptrs in
4215 all classes that need them. */
4216 if (!TYPE_VFIELD (t) && (*virtuals_p || TYPE_CONTAINS_VPTR_P (t)))
4217 {
4218 /* We build this decl with vtbl_ptr_type_node, which is a
4219 `vtable_entry_type*'. It might seem more precise to use
4220 `vtable_entry_type (*)[N]' where N is the number of virtual
4221 functions. However, that would require the vtable pointer in
4222 base classes to have a different type than the vtable pointer
4223 in derived classes. We could make that happen, but that
4224 still wouldn't solve all the problems. In particular, the
4225 type-based alias analysis code would decide that assignments
4226 to the base class vtable pointer can't alias assignments to
4227 the derived class vtable pointer, since they have different
4228 types. Thus, in a derived class destructor, where the base
4229 class constructor was inlined, we could generate bad code for
4230 setting up the vtable pointer.
4231
4232 Therefore, we use one type for all vtable pointers. We still
4233 use a type-correct type; it's just doesn't indicate the array
4234 bounds. That's better than using `void*' or some such; it's
4235 cleaner, and it let's the alias analysis code know that these
4236 stores cannot alias stores to void*! */
4237 tree field;
4238
4239 field = build_decl (FIELD_DECL, get_vfield_name (t), vtbl_ptr_type_node);
4240 DECL_VIRTUAL_P (field) = 1;
4241 DECL_ARTIFICIAL (field) = 1;
4242 DECL_FIELD_CONTEXT (field) = t;
4243 DECL_FCONTEXT (field) = t;
4244
4245 TYPE_VFIELD (t) = field;
4246
4247 /* This class is non-empty. */
4248 CLASSTYPE_EMPTY_P (t) = 0;
4249
4250 return field;
4251 }
4252
4253 return NULL_TREE;
4254 }
4255
4256 /* Fixup the inline function given by INFO now that the class is
4257 complete. */
4258
4259 static void
fixup_pending_inline(tree fn)4260 fixup_pending_inline (tree fn)
4261 {
4262 if (DECL_PENDING_INLINE_INFO (fn))
4263 {
4264 tree args = DECL_ARGUMENTS (fn);
4265 while (args)
4266 {
4267 DECL_CONTEXT (args) = fn;
4268 args = TREE_CHAIN (args);
4269 }
4270 }
4271 }
4272
4273 /* Fixup the inline methods and friends in TYPE now that TYPE is
4274 complete. */
4275
4276 static void
fixup_inline_methods(tree type)4277 fixup_inline_methods (tree type)
4278 {
4279 tree method = TYPE_METHODS (type);
4280 VEC(tree,gc) *friends;
4281 unsigned ix;
4282
4283 if (method && TREE_CODE (method) == TREE_VEC)
4284 {
4285 if (TREE_VEC_ELT (method, 1))
4286 method = TREE_VEC_ELT (method, 1);
4287 else if (TREE_VEC_ELT (method, 0))
4288 method = TREE_VEC_ELT (method, 0);
4289 else
4290 method = TREE_VEC_ELT (method, 2);
4291 }
4292
4293 /* Do inline member functions. */
4294 for (; method; method = TREE_CHAIN (method))
4295 fixup_pending_inline (method);
4296
4297 /* Do friends. */
4298 for (friends = CLASSTYPE_INLINE_FRIENDS (type), ix = 0;
4299 VEC_iterate (tree, friends, ix, method); ix++)
4300 fixup_pending_inline (method);
4301 CLASSTYPE_INLINE_FRIENDS (type) = NULL;
4302 }
4303
4304 /* Add OFFSET to all base types of BINFO which is a base in the
4305 hierarchy dominated by T.
4306
4307 OFFSET, which is a type offset, is number of bytes. */
4308
4309 static void
propagate_binfo_offsets(tree binfo,tree offset)4310 propagate_binfo_offsets (tree binfo, tree offset)
4311 {
4312 int i;
4313 tree primary_binfo;
4314 tree base_binfo;
4315
4316 /* Update BINFO's offset. */
4317 BINFO_OFFSET (binfo)
4318 = convert (sizetype,
4319 size_binop (PLUS_EXPR,
4320 convert (ssizetype, BINFO_OFFSET (binfo)),
4321 offset));
4322
4323 /* Find the primary base class. */
4324 primary_binfo = get_primary_binfo (binfo);
4325
4326 if (primary_binfo && BINFO_INHERITANCE_CHAIN (primary_binfo) == binfo)
4327 propagate_binfo_offsets (primary_binfo, offset);
4328
4329 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
4330 downwards. */
4331 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
4332 {
4333 /* Don't do the primary base twice. */
4334 if (base_binfo == primary_binfo)
4335 continue;
4336
4337 if (BINFO_VIRTUAL_P (base_binfo))
4338 continue;
4339
4340 propagate_binfo_offsets (base_binfo, offset);
4341 }
4342 }
4343
4344 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
4345 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
4346 empty subobjects of T. */
4347
4348 static void
layout_virtual_bases(record_layout_info rli,splay_tree offsets)4349 layout_virtual_bases (record_layout_info rli, splay_tree offsets)
4350 {
4351 tree vbase;
4352 tree t = rli->t;
4353 bool first_vbase = true;
4354 tree *next_field;
4355
4356 if (BINFO_N_BASE_BINFOS (TYPE_BINFO (t)) == 0)
4357 return;
4358
4359 if (!abi_version_at_least(2))
4360 {
4361 /* In G++ 3.2, we incorrectly rounded the size before laying out
4362 the virtual bases. */
4363 finish_record_layout (rli, /*free_p=*/false);
4364 #ifdef STRUCTURE_SIZE_BOUNDARY
4365 /* Packed structures don't need to have minimum size. */
4366 if (! TYPE_PACKED (t))
4367 TYPE_ALIGN (t) = MAX (TYPE_ALIGN (t), (unsigned) STRUCTURE_SIZE_BOUNDARY);
4368 #endif
4369 rli->offset = TYPE_SIZE_UNIT (t);
4370 rli->bitpos = bitsize_zero_node;
4371 rli->record_align = TYPE_ALIGN (t);
4372 }
4373
4374 /* Find the last field. The artificial fields created for virtual
4375 bases will go after the last extant field to date. */
4376 next_field = &TYPE_FIELDS (t);
4377 while (*next_field)
4378 next_field = &TREE_CHAIN (*next_field);
4379
4380 /* Go through the virtual bases, allocating space for each virtual
4381 base that is not already a primary base class. These are
4382 allocated in inheritance graph order. */
4383 for (vbase = TYPE_BINFO (t); vbase; vbase = TREE_CHAIN (vbase))
4384 {
4385 if (!BINFO_VIRTUAL_P (vbase))
4386 continue;
4387
4388 if (!BINFO_PRIMARY_P (vbase))
4389 {
4390 tree basetype = TREE_TYPE (vbase);
4391
4392 /* This virtual base is not a primary base of any class in the
4393 hierarchy, so we have to add space for it. */
4394 next_field = build_base_field (rli, vbase,
4395 offsets, next_field);
4396
4397 /* If the first virtual base might have been placed at a
4398 lower address, had we started from CLASSTYPE_SIZE, rather
4399 than TYPE_SIZE, issue a warning. There can be both false
4400 positives and false negatives from this warning in rare
4401 cases; to deal with all the possibilities would probably
4402 require performing both layout algorithms and comparing
4403 the results which is not particularly tractable. */
4404 if (warn_abi
4405 && first_vbase
4406 && (tree_int_cst_lt
4407 (size_binop (CEIL_DIV_EXPR,
4408 round_up (CLASSTYPE_SIZE (t),
4409 CLASSTYPE_ALIGN (basetype)),
4410 bitsize_unit_node),
4411 BINFO_OFFSET (vbase))))
4412 warning (OPT_Wabi,
4413 "offset of virtual base %qT is not ABI-compliant and "
4414 "may change in a future version of GCC",
4415 basetype);
4416
4417 first_vbase = false;
4418 }
4419 }
4420 }
4421
4422 /* Returns the offset of the byte just past the end of the base class
4423 BINFO. */
4424
4425 static tree
end_of_base(tree binfo)4426 end_of_base (tree binfo)
4427 {
4428 tree size;
4429
4430 if (is_empty_class (BINFO_TYPE (binfo)))
4431 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
4432 allocate some space for it. It cannot have virtual bases, so
4433 TYPE_SIZE_UNIT is fine. */
4434 size = TYPE_SIZE_UNIT (BINFO_TYPE (binfo));
4435 else
4436 size = CLASSTYPE_SIZE_UNIT (BINFO_TYPE (binfo));
4437
4438 return size_binop (PLUS_EXPR, BINFO_OFFSET (binfo), size);
4439 }
4440
4441 /* Returns the offset of the byte just past the end of the base class
4442 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
4443 only non-virtual bases are included. */
4444
4445 static tree
end_of_class(tree t,int include_virtuals_p)4446 end_of_class (tree t, int include_virtuals_p)
4447 {
4448 tree result = size_zero_node;
4449 VEC(tree,gc) *vbases;
4450 tree binfo;
4451 tree base_binfo;
4452 tree offset;
4453 int i;
4454
4455 for (binfo = TYPE_BINFO (t), i = 0;
4456 BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
4457 {
4458 if (!include_virtuals_p
4459 && BINFO_VIRTUAL_P (base_binfo)
4460 && (!BINFO_PRIMARY_P (base_binfo)
4461 || BINFO_INHERITANCE_CHAIN (base_binfo) != TYPE_BINFO (t)))
4462 continue;
4463
4464 offset = end_of_base (base_binfo);
4465 if (INT_CST_LT_UNSIGNED (result, offset))
4466 result = offset;
4467 }
4468
4469 /* G++ 3.2 did not check indirect virtual bases. */
4470 if (abi_version_at_least (2) && include_virtuals_p)
4471 for (vbases = CLASSTYPE_VBASECLASSES (t), i = 0;
4472 VEC_iterate (tree, vbases, i, base_binfo); i++)
4473 {
4474 offset = end_of_base (base_binfo);
4475 if (INT_CST_LT_UNSIGNED (result, offset))
4476 result = offset;
4477 }
4478
4479 return result;
4480 }
4481
4482 /* Warn about bases of T that are inaccessible because they are
4483 ambiguous. For example:
4484
4485 struct S {};
4486 struct T : public S {};
4487 struct U : public S, public T {};
4488
4489 Here, `(S*) new U' is not allowed because there are two `S'
4490 subobjects of U. */
4491
4492 static void
warn_about_ambiguous_bases(tree t)4493 warn_about_ambiguous_bases (tree t)
4494 {
4495 int i;
4496 VEC(tree,gc) *vbases;
4497 tree basetype;
4498 tree binfo;
4499 tree base_binfo;
4500
4501 /* If there are no repeated bases, nothing can be ambiguous. */
4502 if (!CLASSTYPE_REPEATED_BASE_P (t))
4503 return;
4504
4505 /* Check direct bases. */
4506 for (binfo = TYPE_BINFO (t), i = 0;
4507 BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
4508 {
4509 basetype = BINFO_TYPE (base_binfo);
4510
4511 if (!lookup_base (t, basetype, ba_unique | ba_quiet, NULL))
4512 warning (0, "direct base %qT inaccessible in %qT due to ambiguity",
4513 basetype, t);
4514 }
4515
4516 /* Check for ambiguous virtual bases. */
4517 if (extra_warnings)
4518 for (vbases = CLASSTYPE_VBASECLASSES (t), i = 0;
4519 VEC_iterate (tree, vbases, i, binfo); i++)
4520 {
4521 basetype = BINFO_TYPE (binfo);
4522
4523 if (!lookup_base (t, basetype, ba_unique | ba_quiet, NULL))
4524 warning (OPT_Wextra, "virtual base %qT inaccessible in %qT due to ambiguity",
4525 basetype, t);
4526 }
4527 }
4528
4529 /* Compare two INTEGER_CSTs K1 and K2. */
4530
4531 static int
splay_tree_compare_integer_csts(splay_tree_key k1,splay_tree_key k2)4532 splay_tree_compare_integer_csts (splay_tree_key k1, splay_tree_key k2)
4533 {
4534 return tree_int_cst_compare ((tree) k1, (tree) k2);
4535 }
4536
4537 /* Increase the size indicated in RLI to account for empty classes
4538 that are "off the end" of the class. */
4539
4540 static void
include_empty_classes(record_layout_info rli)4541 include_empty_classes (record_layout_info rli)
4542 {
4543 tree eoc;
4544 tree rli_size;
4545
4546 /* It might be the case that we grew the class to allocate a
4547 zero-sized base class. That won't be reflected in RLI, yet,
4548 because we are willing to overlay multiple bases at the same
4549 offset. However, now we need to make sure that RLI is big enough
4550 to reflect the entire class. */
4551 eoc = end_of_class (rli->t,
4552 CLASSTYPE_AS_BASE (rli->t) != NULL_TREE);
4553 rli_size = rli_size_unit_so_far (rli);
4554 if (TREE_CODE (rli_size) == INTEGER_CST
4555 && INT_CST_LT_UNSIGNED (rli_size, eoc))
4556 {
4557 if (!abi_version_at_least (2))
4558 /* In version 1 of the ABI, the size of a class that ends with
4559 a bitfield was not rounded up to a whole multiple of a
4560 byte. Because rli_size_unit_so_far returns only the number
4561 of fully allocated bytes, any extra bits were not included
4562 in the size. */
4563 rli->bitpos = round_down (rli->bitpos, BITS_PER_UNIT);
4564 else
4565 /* The size should have been rounded to a whole byte. */
4566 gcc_assert (tree_int_cst_equal
4567 (rli->bitpos, round_down (rli->bitpos, BITS_PER_UNIT)));
4568 rli->bitpos
4569 = size_binop (PLUS_EXPR,
4570 rli->bitpos,
4571 size_binop (MULT_EXPR,
4572 convert (bitsizetype,
4573 size_binop (MINUS_EXPR,
4574 eoc, rli_size)),
4575 bitsize_int (BITS_PER_UNIT)));
4576 normalize_rli (rli);
4577 }
4578 }
4579
4580 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
4581 BINFO_OFFSETs for all of the base-classes. Position the vtable
4582 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
4583
4584 static void
layout_class_type(tree t,tree * virtuals_p)4585 layout_class_type (tree t, tree *virtuals_p)
4586 {
4587 tree non_static_data_members;
4588 tree field;
4589 tree vptr;
4590 record_layout_info rli;
4591 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
4592 types that appear at that offset. */
4593 splay_tree empty_base_offsets;
4594 /* True if the last field layed out was a bit-field. */
4595 bool last_field_was_bitfield = false;
4596 /* The location at which the next field should be inserted. */
4597 tree *next_field;
4598 /* T, as a base class. */
4599 tree base_t;
4600
4601 /* Keep track of the first non-static data member. */
4602 non_static_data_members = TYPE_FIELDS (t);
4603
4604 /* Start laying out the record. */
4605 rli = start_record_layout (t);
4606
4607 /* Mark all the primary bases in the hierarchy. */
4608 determine_primary_bases (t);
4609
4610 /* Create a pointer to our virtual function table. */
4611 vptr = create_vtable_ptr (t, virtuals_p);
4612
4613 /* The vptr is always the first thing in the class. */
4614 if (vptr)
4615 {
4616 TREE_CHAIN (vptr) = TYPE_FIELDS (t);
4617 TYPE_FIELDS (t) = vptr;
4618 next_field = &TREE_CHAIN (vptr);
4619 place_field (rli, vptr);
4620 }
4621 else
4622 next_field = &TYPE_FIELDS (t);
4623
4624 /* Build FIELD_DECLs for all of the non-virtual base-types. */
4625 empty_base_offsets = splay_tree_new (splay_tree_compare_integer_csts,
4626 NULL, NULL);
4627 build_base_fields (rli, empty_base_offsets, next_field);
4628
4629 /* Layout the non-static data members. */
4630 for (field = non_static_data_members; field; field = TREE_CHAIN (field))
4631 {
4632 tree type;
4633 tree padding;
4634
4635 /* We still pass things that aren't non-static data members to
4636 the back-end, in case it wants to do something with them. */
4637 if (TREE_CODE (field) != FIELD_DECL)
4638 {
4639 place_field (rli, field);
4640 /* If the static data member has incomplete type, keep track
4641 of it so that it can be completed later. (The handling
4642 of pending statics in finish_record_layout is
4643 insufficient; consider:
4644
4645 struct S1;
4646 struct S2 { static S1 s1; };
4647
4648 At this point, finish_record_layout will be called, but
4649 S1 is still incomplete.) */
4650 if (TREE_CODE (field) == VAR_DECL)
4651 {
4652 maybe_register_incomplete_var (field);
4653 /* The visibility of static data members is determined
4654 at their point of declaration, not their point of
4655 definition. */
4656 determine_visibility (field);
4657 }
4658 continue;
4659 }
4660
4661 type = TREE_TYPE (field);
4662 if (type == error_mark_node)
4663 continue;
4664
4665 padding = NULL_TREE;
4666
4667 /* If this field is a bit-field whose width is greater than its
4668 type, then there are some special rules for allocating
4669 it. */
4670 if (DECL_C_BIT_FIELD (field)
4671 && INT_CST_LT (TYPE_SIZE (type), DECL_SIZE (field)))
4672 {
4673 integer_type_kind itk;
4674 tree integer_type;
4675 bool was_unnamed_p = false;
4676 /* We must allocate the bits as if suitably aligned for the
4677 longest integer type that fits in this many bits. type
4678 of the field. Then, we are supposed to use the left over
4679 bits as additional padding. */
4680 for (itk = itk_char; itk != itk_none; ++itk)
4681 if (INT_CST_LT (DECL_SIZE (field),
4682 TYPE_SIZE (integer_types[itk])))
4683 break;
4684
4685 /* ITK now indicates a type that is too large for the
4686 field. We have to back up by one to find the largest
4687 type that fits. */
4688 integer_type = integer_types[itk - 1];
4689
4690 /* Figure out how much additional padding is required. GCC
4691 3.2 always created a padding field, even if it had zero
4692 width. */
4693 if (!abi_version_at_least (2)
4694 || INT_CST_LT (TYPE_SIZE (integer_type), DECL_SIZE (field)))
4695 {
4696 if (abi_version_at_least (2) && TREE_CODE (t) == UNION_TYPE)
4697 /* In a union, the padding field must have the full width
4698 of the bit-field; all fields start at offset zero. */
4699 padding = DECL_SIZE (field);
4700 else
4701 {
4702 if (TREE_CODE (t) == UNION_TYPE)
4703 warning (OPT_Wabi, "size assigned to %qT may not be "
4704 "ABI-compliant and may change in a future "
4705 "version of GCC",
4706 t);
4707 padding = size_binop (MINUS_EXPR, DECL_SIZE (field),
4708 TYPE_SIZE (integer_type));
4709 }
4710 }
4711 #ifdef PCC_BITFIELD_TYPE_MATTERS
4712 /* An unnamed bitfield does not normally affect the
4713 alignment of the containing class on a target where
4714 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
4715 make any exceptions for unnamed bitfields when the
4716 bitfields are longer than their types. Therefore, we
4717 temporarily give the field a name. */
4718 if (PCC_BITFIELD_TYPE_MATTERS && !DECL_NAME (field))
4719 {
4720 was_unnamed_p = true;
4721 DECL_NAME (field) = make_anon_name ();
4722 }
4723 #endif
4724 DECL_SIZE (field) = TYPE_SIZE (integer_type);
4725 DECL_ALIGN (field) = TYPE_ALIGN (integer_type);
4726 DECL_USER_ALIGN (field) = TYPE_USER_ALIGN (integer_type);
4727 layout_nonempty_base_or_field (rli, field, NULL_TREE,
4728 empty_base_offsets);
4729 if (was_unnamed_p)
4730 DECL_NAME (field) = NULL_TREE;
4731 /* Now that layout has been performed, set the size of the
4732 field to the size of its declared type; the rest of the
4733 field is effectively invisible. */
4734 DECL_SIZE (field) = TYPE_SIZE (type);
4735 /* We must also reset the DECL_MODE of the field. */
4736 if (abi_version_at_least (2))
4737 DECL_MODE (field) = TYPE_MODE (type);
4738 else if (warn_abi
4739 && DECL_MODE (field) != TYPE_MODE (type))
4740 /* Versions of G++ before G++ 3.4 did not reset the
4741 DECL_MODE. */
4742 warning (OPT_Wabi,
4743 "the offset of %qD may not be ABI-compliant and may "
4744 "change in a future version of GCC", field);
4745 }
4746 else
4747 layout_nonempty_base_or_field (rli, field, NULL_TREE,
4748 empty_base_offsets);
4749
4750 /* Remember the location of any empty classes in FIELD. */
4751 if (abi_version_at_least (2))
4752 record_subobject_offsets (TREE_TYPE (field),
4753 byte_position(field),
4754 empty_base_offsets,
4755 /*is_data_member=*/true);
4756
4757 /* If a bit-field does not immediately follow another bit-field,
4758 and yet it starts in the middle of a byte, we have failed to
4759 comply with the ABI. */
4760 if (warn_abi
4761 && DECL_C_BIT_FIELD (field)
4762 /* The TREE_NO_WARNING flag gets set by Objective-C when
4763 laying out an Objective-C class. The ObjC ABI differs
4764 from the C++ ABI, and so we do not want a warning
4765 here. */
4766 && !TREE_NO_WARNING (field)
4767 && !last_field_was_bitfield
4768 && !integer_zerop (size_binop (TRUNC_MOD_EXPR,
4769 DECL_FIELD_BIT_OFFSET (field),
4770 bitsize_unit_node)))
4771 warning (OPT_Wabi, "offset of %q+D is not ABI-compliant and may "
4772 "change in a future version of GCC", field);
4773
4774 /* G++ used to use DECL_FIELD_OFFSET as if it were the byte
4775 offset of the field. */
4776 if (warn_abi
4777 && !tree_int_cst_equal (DECL_FIELD_OFFSET (field),
4778 byte_position (field))
4779 && contains_empty_class_p (TREE_TYPE (field)))
4780 warning (OPT_Wabi, "%q+D contains empty classes which may cause base "
4781 "classes to be placed at different locations in a "
4782 "future version of GCC", field);
4783
4784 /* The middle end uses the type of expressions to determine the
4785 possible range of expression values. In order to optimize
4786 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
4787 must be made aware of the width of "i", via its type.
4788
4789 Because C++ does not have integer types of arbitrary width,
4790 we must (for the purposes of the front end) convert from the
4791 type assigned here to the declared type of the bitfield
4792 whenever a bitfield expression is used as an rvalue.
4793 Similarly, when assigning a value to a bitfield, the value
4794 must be converted to the type given the bitfield here. */
4795 if (DECL_C_BIT_FIELD (field))
4796 {
4797 tree ftype;
4798 unsigned HOST_WIDE_INT width;
4799 ftype = TREE_TYPE (field);
4800 width = tree_low_cst (DECL_SIZE (field), /*unsignedp=*/1);
4801 if (width != TYPE_PRECISION (ftype))
4802 TREE_TYPE (field)
4803 = c_build_bitfield_integer_type (width,
4804 TYPE_UNSIGNED (ftype));
4805 }
4806
4807 /* If we needed additional padding after this field, add it
4808 now. */
4809 if (padding)
4810 {
4811 tree padding_field;
4812
4813 padding_field = build_decl (FIELD_DECL,
4814 NULL_TREE,
4815 char_type_node);
4816 DECL_BIT_FIELD (padding_field) = 1;
4817 DECL_SIZE (padding_field) = padding;
4818 DECL_CONTEXT (padding_field) = t;
4819 DECL_ARTIFICIAL (padding_field) = 1;
4820 DECL_IGNORED_P (padding_field) = 1;
4821 layout_nonempty_base_or_field (rli, padding_field,
4822 NULL_TREE,
4823 empty_base_offsets);
4824 }
4825
4826 last_field_was_bitfield = DECL_C_BIT_FIELD (field);
4827 }
4828
4829 if (abi_version_at_least (2) && !integer_zerop (rli->bitpos))
4830 {
4831 /* Make sure that we are on a byte boundary so that the size of
4832 the class without virtual bases will always be a round number
4833 of bytes. */
4834 rli->bitpos = round_up (rli->bitpos, BITS_PER_UNIT);
4835 normalize_rli (rli);
4836 }
4837
4838 /* G++ 3.2 does not allow virtual bases to be overlaid with tail
4839 padding. */
4840 if (!abi_version_at_least (2))
4841 include_empty_classes(rli);
4842
4843 /* Delete all zero-width bit-fields from the list of fields. Now
4844 that the type is laid out they are no longer important. */
4845 remove_zero_width_bit_fields (t);
4846
4847 /* Create the version of T used for virtual bases. We do not use
4848 make_aggr_type for this version; this is an artificial type. For
4849 a POD type, we just reuse T. */
4850 if (CLASSTYPE_NON_POD_P (t) || CLASSTYPE_EMPTY_P (t))
4851 {
4852 base_t = make_node (TREE_CODE (t));
4853
4854 /* Set the size and alignment for the new type. In G++ 3.2, all
4855 empty classes were considered to have size zero when used as
4856 base classes. */
4857 if (!abi_version_at_least (2) && CLASSTYPE_EMPTY_P (t))
4858 {
4859 TYPE_SIZE (base_t) = bitsize_zero_node;
4860 TYPE_SIZE_UNIT (base_t) = size_zero_node;
4861 if (warn_abi && !integer_zerop (rli_size_unit_so_far (rli)))
4862 warning (OPT_Wabi,
4863 "layout of classes derived from empty class %qT "
4864 "may change in a future version of GCC",
4865 t);
4866 }
4867 else
4868 {
4869 tree eoc;
4870
4871 /* If the ABI version is not at least two, and the last
4872 field was a bit-field, RLI may not be on a byte
4873 boundary. In particular, rli_size_unit_so_far might
4874 indicate the last complete byte, while rli_size_so_far
4875 indicates the total number of bits used. Therefore,
4876 rli_size_so_far, rather than rli_size_unit_so_far, is
4877 used to compute TYPE_SIZE_UNIT. */
4878 eoc = end_of_class (t, /*include_virtuals_p=*/0);
4879 TYPE_SIZE_UNIT (base_t)
4880 = size_binop (MAX_EXPR,
4881 convert (sizetype,
4882 size_binop (CEIL_DIV_EXPR,
4883 rli_size_so_far (rli),
4884 bitsize_int (BITS_PER_UNIT))),
4885 eoc);
4886 TYPE_SIZE (base_t)
4887 = size_binop (MAX_EXPR,
4888 rli_size_so_far (rli),
4889 size_binop (MULT_EXPR,
4890 convert (bitsizetype, eoc),
4891 bitsize_int (BITS_PER_UNIT)));
4892 }
4893 TYPE_ALIGN (base_t) = rli->record_align;
4894 TYPE_USER_ALIGN (base_t) = TYPE_USER_ALIGN (t);
4895
4896 /* Copy the fields from T. */
4897 next_field = &TYPE_FIELDS (base_t);
4898 for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
4899 if (TREE_CODE (field) == FIELD_DECL)
4900 {
4901 *next_field = build_decl (FIELD_DECL,
4902 DECL_NAME (field),
4903 TREE_TYPE (field));
4904 DECL_CONTEXT (*next_field) = base_t;
4905 DECL_FIELD_OFFSET (*next_field) = DECL_FIELD_OFFSET (field);
4906 DECL_FIELD_BIT_OFFSET (*next_field)
4907 = DECL_FIELD_BIT_OFFSET (field);
4908 DECL_SIZE (*next_field) = DECL_SIZE (field);
4909 DECL_MODE (*next_field) = DECL_MODE (field);
4910 next_field = &TREE_CHAIN (*next_field);
4911 }
4912
4913 /* Record the base version of the type. */
4914 CLASSTYPE_AS_BASE (t) = base_t;
4915 TYPE_CONTEXT (base_t) = t;
4916 }
4917 else
4918 CLASSTYPE_AS_BASE (t) = t;
4919
4920 /* Every empty class contains an empty class. */
4921 if (CLASSTYPE_EMPTY_P (t))
4922 CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
4923
4924 /* Set the TYPE_DECL for this type to contain the right
4925 value for DECL_OFFSET, so that we can use it as part
4926 of a COMPONENT_REF for multiple inheritance. */
4927 layout_decl (TYPE_MAIN_DECL (t), 0);
4928
4929 /* Now fix up any virtual base class types that we left lying
4930 around. We must get these done before we try to lay out the
4931 virtual function table. As a side-effect, this will remove the
4932 base subobject fields. */
4933 layout_virtual_bases (rli, empty_base_offsets);
4934
4935 /* Make sure that empty classes are reflected in RLI at this
4936 point. */
4937 include_empty_classes(rli);
4938
4939 /* Make sure not to create any structures with zero size. */
4940 if (integer_zerop (rli_size_unit_so_far (rli)) && CLASSTYPE_EMPTY_P (t))
4941 place_field (rli,
4942 build_decl (FIELD_DECL, NULL_TREE, char_type_node));
4943
4944 /* Let the back-end lay out the type. */
4945 finish_record_layout (rli, /*free_p=*/true);
4946
4947 /* Warn about bases that can't be talked about due to ambiguity. */
4948 warn_about_ambiguous_bases (t);
4949
4950 /* Now that we're done with layout, give the base fields the real types. */
4951 for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
4952 if (DECL_ARTIFICIAL (field) && IS_FAKE_BASE_TYPE (TREE_TYPE (field)))
4953 TREE_TYPE (field) = TYPE_CONTEXT (TREE_TYPE (field));
4954
4955 /* Clean up. */
4956 splay_tree_delete (empty_base_offsets);
4957
4958 if (CLASSTYPE_EMPTY_P (t)
4959 && tree_int_cst_lt (sizeof_biggest_empty_class,
4960 TYPE_SIZE_UNIT (t)))
4961 sizeof_biggest_empty_class = TYPE_SIZE_UNIT (t);
4962 }
4963
4964 /* Determine the "key method" for the class type indicated by TYPE,
4965 and set CLASSTYPE_KEY_METHOD accordingly. */
4966
4967 void
determine_key_method(tree type)4968 determine_key_method (tree type)
4969 {
4970 tree method;
4971
4972 if (TYPE_FOR_JAVA (type)
4973 || processing_template_decl
4974 || CLASSTYPE_TEMPLATE_INSTANTIATION (type)
4975 || CLASSTYPE_INTERFACE_KNOWN (type))
4976 return;
4977
4978 /* The key method is the first non-pure virtual function that is not
4979 inline at the point of class definition. On some targets the
4980 key function may not be inline; those targets should not call
4981 this function until the end of the translation unit. */
4982 for (method = TYPE_METHODS (type); method != NULL_TREE;
4983 method = TREE_CHAIN (method))
4984 if (DECL_VINDEX (method) != NULL_TREE
4985 && ! DECL_DECLARED_INLINE_P (method)
4986 && ! DECL_PURE_VIRTUAL_P (method))
4987 {
4988 CLASSTYPE_KEY_METHOD (type) = method;
4989 break;
4990 }
4991
4992 return;
4993 }
4994
4995 /* Perform processing required when the definition of T (a class type)
4996 is complete. */
4997
4998 void
finish_struct_1(tree t)4999 finish_struct_1 (tree t)
5000 {
5001 tree x;
5002 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
5003 tree virtuals = NULL_TREE;
5004 int n_fields = 0;
5005
5006 if (COMPLETE_TYPE_P (t))
5007 {
5008 gcc_assert (IS_AGGR_TYPE (t));
5009 error ("redefinition of %q#T", t);
5010 popclass ();
5011 return;
5012 }
5013
5014 /* If this type was previously laid out as a forward reference,
5015 make sure we lay it out again. */
5016 TYPE_SIZE (t) = NULL_TREE;
5017 CLASSTYPE_PRIMARY_BINFO (t) = NULL_TREE;
5018
5019 fixup_inline_methods (t);
5020
5021 /* Make assumptions about the class; we'll reset the flags if
5022 necessary. */
5023 CLASSTYPE_EMPTY_P (t) = 1;
5024 CLASSTYPE_NEARLY_EMPTY_P (t) = 1;
5025 CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 0;
5026
5027 /* Do end-of-class semantic processing: checking the validity of the
5028 bases and members and add implicitly generated methods. */
5029 check_bases_and_members (t);
5030
5031 /* Find the key method. */
5032 if (TYPE_CONTAINS_VPTR_P (t))
5033 {
5034 /* The Itanium C++ ABI permits the key method to be chosen when
5035 the class is defined -- even though the key method so
5036 selected may later turn out to be an inline function. On
5037 some systems (such as ARM Symbian OS) the key method cannot
5038 be determined until the end of the translation unit. On such
5039 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
5040 will cause the class to be added to KEYED_CLASSES. Then, in
5041 finish_file we will determine the key method. */
5042 if (targetm.cxx.key_method_may_be_inline ())
5043 determine_key_method (t);
5044
5045 /* If a polymorphic class has no key method, we may emit the vtable
5046 in every translation unit where the class definition appears. */
5047 if (CLASSTYPE_KEY_METHOD (t) == NULL_TREE)
5048 keyed_classes = tree_cons (NULL_TREE, t, keyed_classes);
5049 }
5050
5051 /* Layout the class itself. */
5052 layout_class_type (t, &virtuals);
5053 if (CLASSTYPE_AS_BASE (t) != t)
5054 /* We use the base type for trivial assignments, and hence it
5055 needs a mode. */
5056 compute_record_mode (CLASSTYPE_AS_BASE (t));
5057
5058 virtuals = modify_all_vtables (t, nreverse (virtuals));
5059
5060 /* If necessary, create the primary vtable for this class. */
5061 if (virtuals || TYPE_CONTAINS_VPTR_P (t))
5062 {
5063 /* We must enter these virtuals into the table. */
5064 if (!CLASSTYPE_HAS_PRIMARY_BASE_P (t))
5065 build_primary_vtable (NULL_TREE, t);
5066 else if (! BINFO_NEW_VTABLE_MARKED (TYPE_BINFO (t)))
5067 /* Here we know enough to change the type of our virtual
5068 function table, but we will wait until later this function. */
5069 build_primary_vtable (CLASSTYPE_PRIMARY_BINFO (t), t);
5070 }
5071
5072 if (TYPE_CONTAINS_VPTR_P (t))
5073 {
5074 int vindex;
5075 tree fn;
5076
5077 if (BINFO_VTABLE (TYPE_BINFO (t)))
5078 gcc_assert (DECL_VIRTUAL_P (BINFO_VTABLE (TYPE_BINFO (t))));
5079 if (!CLASSTYPE_HAS_PRIMARY_BASE_P (t))
5080 gcc_assert (BINFO_VIRTUALS (TYPE_BINFO (t)) == NULL_TREE);
5081
5082 /* Add entries for virtual functions introduced by this class. */
5083 BINFO_VIRTUALS (TYPE_BINFO (t))
5084 = chainon (BINFO_VIRTUALS (TYPE_BINFO (t)), virtuals);
5085
5086 /* Set DECL_VINDEX for all functions declared in this class. */
5087 for (vindex = 0, fn = BINFO_VIRTUALS (TYPE_BINFO (t));
5088 fn;
5089 fn = TREE_CHAIN (fn),
5090 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
5091 ? TARGET_VTABLE_USES_DESCRIPTORS : 1))
5092 {
5093 tree fndecl = BV_FN (fn);
5094
5095 if (DECL_THUNK_P (fndecl))
5096 /* A thunk. We should never be calling this entry directly
5097 from this vtable -- we'd use the entry for the non
5098 thunk base function. */
5099 DECL_VINDEX (fndecl) = NULL_TREE;
5100 else if (TREE_CODE (DECL_VINDEX (fndecl)) != INTEGER_CST)
5101 DECL_VINDEX (fndecl) = build_int_cst (NULL_TREE, vindex);
5102 }
5103 }
5104
5105 finish_struct_bits (t);
5106
5107 /* Complete the rtl for any static member objects of the type we're
5108 working on. */
5109 for (x = TYPE_FIELDS (t); x; x = TREE_CHAIN (x))
5110 if (TREE_CODE (x) == VAR_DECL && TREE_STATIC (x)
5111 && TREE_TYPE (x) != error_mark_node
5112 && same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (x)), t))
5113 DECL_MODE (x) = TYPE_MODE (t);
5114
5115 /* Done with FIELDS...now decide whether to sort these for
5116 faster lookups later.
5117
5118 We use a small number because most searches fail (succeeding
5119 ultimately as the search bores through the inheritance
5120 hierarchy), and we want this failure to occur quickly. */
5121
5122 n_fields = count_fields (TYPE_FIELDS (t));
5123 if (n_fields > 7)
5124 {
5125 struct sorted_fields_type *field_vec = GGC_NEWVAR
5126 (struct sorted_fields_type,
5127 sizeof (struct sorted_fields_type) + n_fields * sizeof (tree));
5128 field_vec->len = n_fields;
5129 add_fields_to_record_type (TYPE_FIELDS (t), field_vec, 0);
5130 qsort (field_vec->elts, n_fields, sizeof (tree),
5131 field_decl_cmp);
5132 if (! DECL_LANG_SPECIFIC (TYPE_MAIN_DECL (t)))
5133 retrofit_lang_decl (TYPE_MAIN_DECL (t));
5134 DECL_SORTED_FIELDS (TYPE_MAIN_DECL (t)) = field_vec;
5135 }
5136
5137 /* Complain if one of the field types requires lower visibility. */
5138 constrain_class_visibility (t);
5139
5140 /* Make the rtl for any new vtables we have created, and unmark
5141 the base types we marked. */
5142 finish_vtbls (t);
5143
5144 /* Build the VTT for T. */
5145 build_vtt (t);
5146
5147 /* This warning does not make sense for Java classes, since they
5148 cannot have destructors. */
5149 if (!TYPE_FOR_JAVA (t) && warn_nonvdtor && TYPE_POLYMORPHIC_P (t))
5150 {
5151 tree dtor;
5152
5153 dtor = CLASSTYPE_DESTRUCTORS (t);
5154 /* Warn only if the dtor is non-private or the class has
5155 friends. */
5156 if (/* An implicitly declared destructor is always public. And,
5157 if it were virtual, we would have created it by now. */
5158 !dtor
5159 || (!DECL_VINDEX (dtor)
5160 && (!TREE_PRIVATE (dtor)
5161 || CLASSTYPE_FRIEND_CLASSES (t)
5162 || DECL_FRIENDLIST (TYPE_MAIN_DECL (t)))))
5163 warning (0, "%q#T has virtual functions but non-virtual destructor",
5164 t);
5165 }
5166
5167 complete_vars (t);
5168
5169 if (warn_overloaded_virtual)
5170 warn_hidden (t);
5171
5172 /* Class layout, assignment of virtual table slots, etc., is now
5173 complete. Give the back end a chance to tweak the visibility of
5174 the class or perform any other required target modifications. */
5175 targetm.cxx.adjust_class_at_definition (t);
5176
5177 maybe_suppress_debug_info (t);
5178
5179 dump_class_hierarchy (t);
5180
5181 /* Finish debugging output for this type. */
5182 rest_of_type_compilation (t, ! LOCAL_CLASS_P (t));
5183 }
5184
5185 /* When T was built up, the member declarations were added in reverse
5186 order. Rearrange them to declaration order. */
5187
5188 void
unreverse_member_declarations(tree t)5189 unreverse_member_declarations (tree t)
5190 {
5191 tree next;
5192 tree prev;
5193 tree x;
5194
5195 /* The following lists are all in reverse order. Put them in
5196 declaration order now. */
5197 TYPE_METHODS (t) = nreverse (TYPE_METHODS (t));
5198 CLASSTYPE_DECL_LIST (t) = nreverse (CLASSTYPE_DECL_LIST (t));
5199
5200 /* Actually, for the TYPE_FIELDS, only the non TYPE_DECLs are in
5201 reverse order, so we can't just use nreverse. */
5202 prev = NULL_TREE;
5203 for (x = TYPE_FIELDS (t);
5204 x && TREE_CODE (x) != TYPE_DECL;
5205 x = next)
5206 {
5207 next = TREE_CHAIN (x);
5208 TREE_CHAIN (x) = prev;
5209 prev = x;
5210 }
5211 if (prev)
5212 {
5213 TREE_CHAIN (TYPE_FIELDS (t)) = x;
5214 if (prev)
5215 TYPE_FIELDS (t) = prev;
5216 }
5217 }
5218
5219 tree
finish_struct(tree t,tree attributes)5220 finish_struct (tree t, tree attributes)
5221 {
5222 location_t saved_loc = input_location;
5223
5224 /* Now that we've got all the field declarations, reverse everything
5225 as necessary. */
5226 unreverse_member_declarations (t);
5227
5228 cplus_decl_attributes (&t, attributes, (int) ATTR_FLAG_TYPE_IN_PLACE);
5229
5230 /* Nadger the current location so that diagnostics point to the start of
5231 the struct, not the end. */
5232 input_location = DECL_SOURCE_LOCATION (TYPE_NAME (t));
5233
5234 if (processing_template_decl)
5235 {
5236 tree x;
5237
5238 finish_struct_methods (t);
5239 TYPE_SIZE (t) = bitsize_zero_node;
5240 TYPE_SIZE_UNIT (t) = size_zero_node;
5241
5242 /* We need to emit an error message if this type was used as a parameter
5243 and it is an abstract type, even if it is a template. We construct
5244 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
5245 account and we call complete_vars with this type, which will check
5246 the PARM_DECLS. Note that while the type is being defined,
5247 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
5248 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
5249 CLASSTYPE_PURE_VIRTUALS (t) = NULL;
5250 for (x = TYPE_METHODS (t); x; x = TREE_CHAIN (x))
5251 if (DECL_PURE_VIRTUAL_P (x))
5252 VEC_safe_push (tree, gc, CLASSTYPE_PURE_VIRTUALS (t), x);
5253 complete_vars (t);
5254 }
5255 else
5256 finish_struct_1 (t);
5257
5258 input_location = saved_loc;
5259
5260 TYPE_BEING_DEFINED (t) = 0;
5261
5262 if (current_class_type)
5263 popclass ();
5264 else
5265 error ("trying to finish struct, but kicked out due to previous parse errors");
5266
5267 if (processing_template_decl && at_function_scope_p ())
5268 add_stmt (build_min (TAG_DEFN, t));
5269
5270 return t;
5271 }
5272
5273 /* Return the dynamic type of INSTANCE, if known.
5274 Used to determine whether the virtual function table is needed
5275 or not.
5276
5277 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
5278 of our knowledge of its type. *NONNULL should be initialized
5279 before this function is called. */
5280
5281 static tree
fixed_type_or_null(tree instance,int * nonnull,int * cdtorp)5282 fixed_type_or_null (tree instance, int* nonnull, int* cdtorp)
5283 {
5284 switch (TREE_CODE (instance))
5285 {
5286 case INDIRECT_REF:
5287 if (POINTER_TYPE_P (TREE_TYPE (instance)))
5288 return NULL_TREE;
5289 else
5290 return fixed_type_or_null (TREE_OPERAND (instance, 0),
5291 nonnull, cdtorp);
5292
5293 case CALL_EXPR:
5294 /* This is a call to a constructor, hence it's never zero. */
5295 if (TREE_HAS_CONSTRUCTOR (instance))
5296 {
5297 if (nonnull)
5298 *nonnull = 1;
5299 return TREE_TYPE (instance);
5300 }
5301 return NULL_TREE;
5302
5303 case SAVE_EXPR:
5304 /* This is a call to a constructor, hence it's never zero. */
5305 if (TREE_HAS_CONSTRUCTOR (instance))
5306 {
5307 if (nonnull)
5308 *nonnull = 1;
5309 return TREE_TYPE (instance);
5310 }
5311 return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5312
5313 case PLUS_EXPR:
5314 case MINUS_EXPR:
5315 if (TREE_CODE (TREE_OPERAND (instance, 0)) == ADDR_EXPR)
5316 return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5317 if (TREE_CODE (TREE_OPERAND (instance, 1)) == INTEGER_CST)
5318 /* Propagate nonnull. */
5319 return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5320 return NULL_TREE;
5321
5322 case NOP_EXPR:
5323 case CONVERT_EXPR:
5324 return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5325
5326 case ADDR_EXPR:
5327 instance = TREE_OPERAND (instance, 0);
5328 if (nonnull)
5329 {
5330 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
5331 with a real object -- given &p->f, p can still be null. */
5332 tree t = get_base_address (instance);
5333 /* ??? Probably should check DECL_WEAK here. */
5334 if (t && DECL_P (t))
5335 *nonnull = 1;
5336 }
5337 return fixed_type_or_null (instance, nonnull, cdtorp);
5338
5339 case COMPONENT_REF:
5340 /* If this component is really a base class reference, then the field
5341 itself isn't definitive. */
5342 if (DECL_FIELD_IS_BASE (TREE_OPERAND (instance, 1)))
5343 return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull, cdtorp);
5344 return fixed_type_or_null (TREE_OPERAND (instance, 1), nonnull, cdtorp);
5345
5346 case VAR_DECL:
5347 case FIELD_DECL:
5348 if (TREE_CODE (TREE_TYPE (instance)) == ARRAY_TYPE
5349 && IS_AGGR_TYPE (TREE_TYPE (TREE_TYPE (instance))))
5350 {
5351 if (nonnull)
5352 *nonnull = 1;
5353 return TREE_TYPE (TREE_TYPE (instance));
5354 }
5355 /* fall through... */
5356 case TARGET_EXPR:
5357 case PARM_DECL:
5358 case RESULT_DECL:
5359 if (IS_AGGR_TYPE (TREE_TYPE (instance)))
5360 {
5361 if (nonnull)
5362 *nonnull = 1;
5363 return TREE_TYPE (instance);
5364 }
5365 else if (instance == current_class_ptr)
5366 {
5367 if (nonnull)
5368 *nonnull = 1;
5369
5370 /* if we're in a ctor or dtor, we know our type. */
5371 if (DECL_LANG_SPECIFIC (current_function_decl)
5372 && (DECL_CONSTRUCTOR_P (current_function_decl)
5373 || DECL_DESTRUCTOR_P (current_function_decl)))
5374 {
5375 if (cdtorp)
5376 *cdtorp = 1;
5377 return TREE_TYPE (TREE_TYPE (instance));
5378 }
5379 }
5380 else if (TREE_CODE (TREE_TYPE (instance)) == REFERENCE_TYPE)
5381 {
5382 /* We only need one hash table because it is always left empty. */
5383 static htab_t ht;
5384 if (!ht)
5385 ht = htab_create (37,
5386 htab_hash_pointer,
5387 htab_eq_pointer,
5388 /*htab_del=*/NULL);
5389
5390 /* Reference variables should be references to objects. */
5391 if (nonnull)
5392 *nonnull = 1;
5393
5394 /* Enter the INSTANCE in a table to prevent recursion; a
5395 variable's initializer may refer to the variable
5396 itself. */
5397 if (TREE_CODE (instance) == VAR_DECL
5398 && DECL_INITIAL (instance)
5399 && !htab_find (ht, instance))
5400 {
5401 tree type;
5402 void **slot;
5403
5404 slot = htab_find_slot (ht, instance, INSERT);
5405 *slot = instance;
5406 type = fixed_type_or_null (DECL_INITIAL (instance),
5407 nonnull, cdtorp);
5408 htab_remove_elt (ht, instance);
5409
5410 return type;
5411 }
5412 }
5413 return NULL_TREE;
5414
5415 default:
5416 return NULL_TREE;
5417 }
5418 }
5419
5420 /* Return nonzero if the dynamic type of INSTANCE is known, and
5421 equivalent to the static type. We also handle the case where
5422 INSTANCE is really a pointer. Return negative if this is a
5423 ctor/dtor. There the dynamic type is known, but this might not be
5424 the most derived base of the original object, and hence virtual
5425 bases may not be layed out according to this type.
5426
5427 Used to determine whether the virtual function table is needed
5428 or not.
5429
5430 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
5431 of our knowledge of its type. *NONNULL should be initialized
5432 before this function is called. */
5433
5434 int
resolves_to_fixed_type_p(tree instance,int * nonnull)5435 resolves_to_fixed_type_p (tree instance, int* nonnull)
5436 {
5437 tree t = TREE_TYPE (instance);
5438 int cdtorp = 0;
5439
5440 tree fixed = fixed_type_or_null (instance, nonnull, &cdtorp);
5441 if (fixed == NULL_TREE)
5442 return 0;
5443 if (POINTER_TYPE_P (t))
5444 t = TREE_TYPE (t);
5445 if (!same_type_ignoring_top_level_qualifiers_p (t, fixed))
5446 return 0;
5447 return cdtorp ? -1 : 1;
5448 }
5449
5450
5451 void
init_class_processing(void)5452 init_class_processing (void)
5453 {
5454 current_class_depth = 0;
5455 current_class_stack_size = 10;
5456 current_class_stack
5457 = XNEWVEC (struct class_stack_node, current_class_stack_size);
5458 local_classes = VEC_alloc (tree, gc, 8);
5459 sizeof_biggest_empty_class = size_zero_node;
5460
5461 ridpointers[(int) RID_PUBLIC] = access_public_node;
5462 ridpointers[(int) RID_PRIVATE] = access_private_node;
5463 ridpointers[(int) RID_PROTECTED] = access_protected_node;
5464 }
5465
5466 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
5467
5468 static void
restore_class_cache(void)5469 restore_class_cache (void)
5470 {
5471 tree type;
5472
5473 /* We are re-entering the same class we just left, so we don't
5474 have to search the whole inheritance matrix to find all the
5475 decls to bind again. Instead, we install the cached
5476 class_shadowed list and walk through it binding names. */
5477 push_binding_level (previous_class_level);
5478 class_binding_level = previous_class_level;
5479 /* Restore IDENTIFIER_TYPE_VALUE. */
5480 for (type = class_binding_level->type_shadowed;
5481 type;
5482 type = TREE_CHAIN (type))
5483 SET_IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (type), TREE_TYPE (type));
5484 }
5485
5486 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
5487 appropriate for TYPE.
5488
5489 So that we may avoid calls to lookup_name, we cache the _TYPE
5490 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
5491
5492 For multiple inheritance, we perform a two-pass depth-first search
5493 of the type lattice. */
5494
5495 void
pushclass(tree type)5496 pushclass (tree type)
5497 {
5498 class_stack_node_t csn;
5499
5500 type = TYPE_MAIN_VARIANT (type);
5501
5502 /* Make sure there is enough room for the new entry on the stack. */
5503 if (current_class_depth + 1 >= current_class_stack_size)
5504 {
5505 current_class_stack_size *= 2;
5506 current_class_stack
5507 = XRESIZEVEC (struct class_stack_node, current_class_stack,
5508 current_class_stack_size);
5509 }
5510
5511 /* Insert a new entry on the class stack. */
5512 csn = current_class_stack + current_class_depth;
5513 csn->name = current_class_name;
5514 csn->type = current_class_type;
5515 csn->access = current_access_specifier;
5516 csn->names_used = 0;
5517 csn->hidden = 0;
5518 current_class_depth++;
5519
5520 /* Now set up the new type. */
5521 current_class_name = TYPE_NAME (type);
5522 if (TREE_CODE (current_class_name) == TYPE_DECL)
5523 current_class_name = DECL_NAME (current_class_name);
5524 current_class_type = type;
5525
5526 /* By default, things in classes are private, while things in
5527 structures or unions are public. */
5528 current_access_specifier = (CLASSTYPE_DECLARED_CLASS (type)
5529 ? access_private_node
5530 : access_public_node);
5531
5532 if (previous_class_level
5533 && type != previous_class_level->this_entity
5534 && current_class_depth == 1)
5535 {
5536 /* Forcibly remove any old class remnants. */
5537 invalidate_class_lookup_cache ();
5538 }
5539
5540 if (!previous_class_level
5541 || type != previous_class_level->this_entity
5542 || current_class_depth > 1)
5543 pushlevel_class ();
5544 else
5545 restore_class_cache ();
5546 }
5547
5548 /* When we exit a toplevel class scope, we save its binding level so
5549 that we can restore it quickly. Here, we've entered some other
5550 class, so we must invalidate our cache. */
5551
5552 void
invalidate_class_lookup_cache(void)5553 invalidate_class_lookup_cache (void)
5554 {
5555 previous_class_level = NULL;
5556 }
5557
5558 /* Get out of the current class scope. If we were in a class scope
5559 previously, that is the one popped to. */
5560
5561 void
popclass(void)5562 popclass (void)
5563 {
5564 poplevel_class ();
5565
5566 current_class_depth--;
5567 current_class_name = current_class_stack[current_class_depth].name;
5568 current_class_type = current_class_stack[current_class_depth].type;
5569 current_access_specifier = current_class_stack[current_class_depth].access;
5570 if (current_class_stack[current_class_depth].names_used)
5571 splay_tree_delete (current_class_stack[current_class_depth].names_used);
5572 }
5573
5574 /* Mark the top of the class stack as hidden. */
5575
5576 void
push_class_stack(void)5577 push_class_stack (void)
5578 {
5579 if (current_class_depth)
5580 ++current_class_stack[current_class_depth - 1].hidden;
5581 }
5582
5583 /* Mark the top of the class stack as un-hidden. */
5584
5585 void
pop_class_stack(void)5586 pop_class_stack (void)
5587 {
5588 if (current_class_depth)
5589 --current_class_stack[current_class_depth - 1].hidden;
5590 }
5591
5592 /* Returns 1 if the class type currently being defined is either T or
5593 a nested type of T. */
5594
5595 bool
currently_open_class(tree t)5596 currently_open_class (tree t)
5597 {
5598 int i;
5599
5600 /* We start looking from 1 because entry 0 is from global scope,
5601 and has no type. */
5602 for (i = current_class_depth; i > 0; --i)
5603 {
5604 tree c;
5605 if (i == current_class_depth)
5606 c = current_class_type;
5607 else
5608 {
5609 if (current_class_stack[i].hidden)
5610 break;
5611 c = current_class_stack[i].type;
5612 }
5613 if (!c)
5614 continue;
5615 if (same_type_p (c, t))
5616 return true;
5617 }
5618 return false;
5619 }
5620
5621 /* If either current_class_type or one of its enclosing classes are derived
5622 from T, return the appropriate type. Used to determine how we found
5623 something via unqualified lookup. */
5624
5625 tree
currently_open_derived_class(tree t)5626 currently_open_derived_class (tree t)
5627 {
5628 int i;
5629
5630 /* The bases of a dependent type are unknown. */
5631 if (dependent_type_p (t))
5632 return NULL_TREE;
5633
5634 if (!current_class_type)
5635 return NULL_TREE;
5636
5637 if (DERIVED_FROM_P (t, current_class_type))
5638 return current_class_type;
5639
5640 for (i = current_class_depth - 1; i > 0; --i)
5641 {
5642 if (current_class_stack[i].hidden)
5643 break;
5644 if (DERIVED_FROM_P (t, current_class_stack[i].type))
5645 return current_class_stack[i].type;
5646 }
5647
5648 return NULL_TREE;
5649 }
5650
5651 /* When entering a class scope, all enclosing class scopes' names with
5652 static meaning (static variables, static functions, types and
5653 enumerators) have to be visible. This recursive function calls
5654 pushclass for all enclosing class contexts until global or a local
5655 scope is reached. TYPE is the enclosed class. */
5656
5657 void
push_nested_class(tree type)5658 push_nested_class (tree type)
5659 {
5660 tree context;
5661
5662 /* A namespace might be passed in error cases, like A::B:C. */
5663 if (type == NULL_TREE
5664 || type == error_mark_node
5665 || TREE_CODE (type) == NAMESPACE_DECL
5666 || ! IS_AGGR_TYPE (type)
5667 || TREE_CODE (type) == TEMPLATE_TYPE_PARM
5668 || TREE_CODE (type) == BOUND_TEMPLATE_TEMPLATE_PARM)
5669 return;
5670
5671 context = DECL_CONTEXT (TYPE_MAIN_DECL (type));
5672
5673 if (context && CLASS_TYPE_P (context))
5674 push_nested_class (context);
5675 pushclass (type);
5676 }
5677
5678 /* Undoes a push_nested_class call. */
5679
5680 void
pop_nested_class(void)5681 pop_nested_class (void)
5682 {
5683 tree context = DECL_CONTEXT (TYPE_MAIN_DECL (current_class_type));
5684
5685 popclass ();
5686 if (context && CLASS_TYPE_P (context))
5687 pop_nested_class ();
5688 }
5689
5690 /* Returns the number of extern "LANG" blocks we are nested within. */
5691
5692 int
current_lang_depth(void)5693 current_lang_depth (void)
5694 {
5695 return VEC_length (tree, current_lang_base);
5696 }
5697
5698 /* Set global variables CURRENT_LANG_NAME to appropriate value
5699 so that behavior of name-mangling machinery is correct. */
5700
5701 void
push_lang_context(tree name)5702 push_lang_context (tree name)
5703 {
5704 VEC_safe_push (tree, gc, current_lang_base, current_lang_name);
5705
5706 if (name == lang_name_cplusplus)
5707 {
5708 current_lang_name = name;
5709 }
5710 else if (name == lang_name_java)
5711 {
5712 current_lang_name = name;
5713 /* DECL_IGNORED_P is initially set for these types, to avoid clutter.
5714 (See record_builtin_java_type in decl.c.) However, that causes
5715 incorrect debug entries if these types are actually used.
5716 So we re-enable debug output after extern "Java". */
5717 DECL_IGNORED_P (TYPE_NAME (java_byte_type_node)) = 0;
5718 DECL_IGNORED_P (TYPE_NAME (java_short_type_node)) = 0;
5719 DECL_IGNORED_P (TYPE_NAME (java_int_type_node)) = 0;
5720 DECL_IGNORED_P (TYPE_NAME (java_long_type_node)) = 0;
5721 DECL_IGNORED_P (TYPE_NAME (java_float_type_node)) = 0;
5722 DECL_IGNORED_P (TYPE_NAME (java_double_type_node)) = 0;
5723 DECL_IGNORED_P (TYPE_NAME (java_char_type_node)) = 0;
5724 DECL_IGNORED_P (TYPE_NAME (java_boolean_type_node)) = 0;
5725 }
5726 else if (name == lang_name_c)
5727 {
5728 current_lang_name = name;
5729 }
5730 else
5731 error ("language string %<\"%E\"%> not recognized", name);
5732 }
5733
5734 /* Get out of the current language scope. */
5735
5736 void
pop_lang_context(void)5737 pop_lang_context (void)
5738 {
5739 current_lang_name = VEC_pop (tree, current_lang_base);
5740 }
5741
5742 /* Type instantiation routines. */
5743
5744 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
5745 matches the TARGET_TYPE. If there is no satisfactory match, return
5746 error_mark_node, and issue an error & warning messages under
5747 control of FLAGS. Permit pointers to member function if FLAGS
5748 permits. If TEMPLATE_ONLY, the name of the overloaded function was
5749 a template-id, and EXPLICIT_TARGS are the explicitly provided
5750 template arguments. If OVERLOAD is for one or more member
5751 functions, then ACCESS_PATH is the base path used to reference
5752 those member functions. */
5753
5754 static tree
resolve_address_of_overloaded_function(tree target_type,tree overload,tsubst_flags_t flags,bool template_only,tree explicit_targs,tree access_path)5755 resolve_address_of_overloaded_function (tree target_type,
5756 tree overload,
5757 tsubst_flags_t flags,
5758 bool template_only,
5759 tree explicit_targs,
5760 tree access_path)
5761 {
5762 /* Here's what the standard says:
5763
5764 [over.over]
5765
5766 If the name is a function template, template argument deduction
5767 is done, and if the argument deduction succeeds, the deduced
5768 arguments are used to generate a single template function, which
5769 is added to the set of overloaded functions considered.
5770
5771 Non-member functions and static member functions match targets of
5772 type "pointer-to-function" or "reference-to-function." Nonstatic
5773 member functions match targets of type "pointer-to-member
5774 function;" the function type of the pointer to member is used to
5775 select the member function from the set of overloaded member
5776 functions. If a nonstatic member function is selected, the
5777 reference to the overloaded function name is required to have the
5778 form of a pointer to member as described in 5.3.1.
5779
5780 If more than one function is selected, any template functions in
5781 the set are eliminated if the set also contains a non-template
5782 function, and any given template function is eliminated if the
5783 set contains a second template function that is more specialized
5784 than the first according to the partial ordering rules 14.5.5.2.
5785 After such eliminations, if any, there shall remain exactly one
5786 selected function. */
5787
5788 int is_ptrmem = 0;
5789 int is_reference = 0;
5790 /* We store the matches in a TREE_LIST rooted here. The functions
5791 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
5792 interoperability with most_specialized_instantiation. */
5793 tree matches = NULL_TREE;
5794 tree fn;
5795
5796 /* By the time we get here, we should be seeing only real
5797 pointer-to-member types, not the internal POINTER_TYPE to
5798 METHOD_TYPE representation. */
5799 gcc_assert (TREE_CODE (target_type) != POINTER_TYPE
5800 || TREE_CODE (TREE_TYPE (target_type)) != METHOD_TYPE);
5801
5802 gcc_assert (is_overloaded_fn (overload));
5803
5804 /* Check that the TARGET_TYPE is reasonable. */
5805 if (TYPE_PTRFN_P (target_type))
5806 /* This is OK. */;
5807 else if (TYPE_PTRMEMFUNC_P (target_type))
5808 /* This is OK, too. */
5809 is_ptrmem = 1;
5810 else if (TREE_CODE (target_type) == FUNCTION_TYPE)
5811 {
5812 /* This is OK, too. This comes from a conversion to reference
5813 type. */
5814 target_type = build_reference_type (target_type);
5815 is_reference = 1;
5816 }
5817 else
5818 {
5819 if (flags & tf_error)
5820 error ("cannot resolve overloaded function %qD based on"
5821 " conversion to type %qT",
5822 DECL_NAME (OVL_FUNCTION (overload)), target_type);
5823 return error_mark_node;
5824 }
5825
5826 /* If we can find a non-template function that matches, we can just
5827 use it. There's no point in generating template instantiations
5828 if we're just going to throw them out anyhow. But, of course, we
5829 can only do this when we don't *need* a template function. */
5830 if (!template_only)
5831 {
5832 tree fns;
5833
5834 for (fns = overload; fns; fns = OVL_NEXT (fns))
5835 {
5836 tree fn = OVL_CURRENT (fns);
5837 tree fntype;
5838
5839 if (TREE_CODE (fn) == TEMPLATE_DECL)
5840 /* We're not looking for templates just yet. */
5841 continue;
5842
5843 if ((TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
5844 != is_ptrmem)
5845 /* We're looking for a non-static member, and this isn't
5846 one, or vice versa. */
5847 continue;
5848
5849 /* Ignore functions which haven't been explicitly
5850 declared. */
5851 if (DECL_ANTICIPATED (fn))
5852 continue;
5853
5854 /* See if there's a match. */
5855 fntype = TREE_TYPE (fn);
5856 if (is_ptrmem)
5857 fntype = build_ptrmemfunc_type (build_pointer_type (fntype));
5858 else if (!is_reference)
5859 fntype = build_pointer_type (fntype);
5860
5861 if (can_convert_arg (target_type, fntype, fn, LOOKUP_NORMAL))
5862 matches = tree_cons (fn, NULL_TREE, matches);
5863 }
5864 }
5865
5866 /* Now, if we've already got a match (or matches), there's no need
5867 to proceed to the template functions. But, if we don't have a
5868 match we need to look at them, too. */
5869 if (!matches)
5870 {
5871 tree target_fn_type;
5872 tree target_arg_types;
5873 tree target_ret_type;
5874 tree fns;
5875
5876 if (is_ptrmem)
5877 target_fn_type
5878 = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (target_type));
5879 else
5880 target_fn_type = TREE_TYPE (target_type);
5881 target_arg_types = TYPE_ARG_TYPES (target_fn_type);
5882 target_ret_type = TREE_TYPE (target_fn_type);
5883
5884 /* Never do unification on the 'this' parameter. */
5885 if (TREE_CODE (target_fn_type) == METHOD_TYPE)
5886 target_arg_types = TREE_CHAIN (target_arg_types);
5887
5888 for (fns = overload; fns; fns = OVL_NEXT (fns))
5889 {
5890 tree fn = OVL_CURRENT (fns);
5891 tree instantiation;
5892 tree instantiation_type;
5893 tree targs;
5894
5895 if (TREE_CODE (fn) != TEMPLATE_DECL)
5896 /* We're only looking for templates. */
5897 continue;
5898
5899 if ((TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
5900 != is_ptrmem)
5901 /* We're not looking for a non-static member, and this is
5902 one, or vice versa. */
5903 continue;
5904
5905 /* Try to do argument deduction. */
5906 targs = make_tree_vec (DECL_NTPARMS (fn));
5907 if (fn_type_unification (fn, explicit_targs, targs,
5908 target_arg_types, target_ret_type,
5909 DEDUCE_EXACT, LOOKUP_NORMAL))
5910 /* Argument deduction failed. */
5911 continue;
5912
5913 /* Instantiate the template. */
5914 instantiation = instantiate_template (fn, targs, flags);
5915 if (instantiation == error_mark_node)
5916 /* Instantiation failed. */
5917 continue;
5918
5919 /* See if there's a match. */
5920 instantiation_type = TREE_TYPE (instantiation);
5921 if (is_ptrmem)
5922 instantiation_type =
5923 build_ptrmemfunc_type (build_pointer_type (instantiation_type));
5924 else if (!is_reference)
5925 instantiation_type = build_pointer_type (instantiation_type);
5926 if (can_convert_arg (target_type, instantiation_type, instantiation,
5927 LOOKUP_NORMAL))
5928 matches = tree_cons (instantiation, fn, matches);
5929 }
5930
5931 /* Now, remove all but the most specialized of the matches. */
5932 if (matches)
5933 {
5934 tree match = most_specialized_instantiation (matches);
5935
5936 if (match != error_mark_node)
5937 matches = tree_cons (TREE_PURPOSE (match),
5938 NULL_TREE,
5939 NULL_TREE);
5940 }
5941 }
5942
5943 /* Now we should have exactly one function in MATCHES. */
5944 if (matches == NULL_TREE)
5945 {
5946 /* There were *no* matches. */
5947 if (flags & tf_error)
5948 {
5949 error ("no matches converting function %qD to type %q#T",
5950 DECL_NAME (OVL_FUNCTION (overload)),
5951 target_type);
5952
5953 /* print_candidates expects a chain with the functions in
5954 TREE_VALUE slots, so we cons one up here (we're losing anyway,
5955 so why be clever?). */
5956 for (; overload; overload = OVL_NEXT (overload))
5957 matches = tree_cons (NULL_TREE, OVL_CURRENT (overload),
5958 matches);
5959
5960 print_candidates (matches);
5961 }
5962 return error_mark_node;
5963 }
5964 else if (TREE_CHAIN (matches))
5965 {
5966 /* There were too many matches. */
5967
5968 if (flags & tf_error)
5969 {
5970 tree match;
5971
5972 error ("converting overloaded function %qD to type %q#T is ambiguous",
5973 DECL_NAME (OVL_FUNCTION (overload)),
5974 target_type);
5975
5976 /* Since print_candidates expects the functions in the
5977 TREE_VALUE slot, we flip them here. */
5978 for (match = matches; match; match = TREE_CHAIN (match))
5979 TREE_VALUE (match) = TREE_PURPOSE (match);
5980
5981 print_candidates (matches);
5982 }
5983
5984 return error_mark_node;
5985 }
5986
5987 /* Good, exactly one match. Now, convert it to the correct type. */
5988 fn = TREE_PURPOSE (matches);
5989
5990 if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)
5991 && !(flags & tf_ptrmem_ok) && !flag_ms_extensions)
5992 {
5993 static int explained;
5994
5995 if (!(flags & tf_error))
5996 return error_mark_node;
5997
5998 pedwarn ("assuming pointer to member %qD", fn);
5999 if (!explained)
6000 {
6001 pedwarn ("(a pointer to member can only be formed with %<&%E%>)", fn);
6002 explained = 1;
6003 }
6004 }
6005
6006 /* If we're doing overload resolution purely for the purpose of
6007 determining conversion sequences, we should not consider the
6008 function used. If this conversion sequence is selected, the
6009 function will be marked as used at this point. */
6010 if (!(flags & tf_conv))
6011 {
6012 mark_used (fn);
6013 /* We could not check access when this expression was originally
6014 created since we did not know at that time to which function
6015 the expression referred. */
6016 if (DECL_FUNCTION_MEMBER_P (fn))
6017 {
6018 gcc_assert (access_path);
6019 perform_or_defer_access_check (access_path, fn, fn);
6020 }
6021 }
6022
6023 if (TYPE_PTRFN_P (target_type) || TYPE_PTRMEMFUNC_P (target_type))
6024 return build_unary_op (ADDR_EXPR, fn, 0);
6025 else
6026 {
6027 /* The target must be a REFERENCE_TYPE. Above, build_unary_op
6028 will mark the function as addressed, but here we must do it
6029 explicitly. */
6030 cxx_mark_addressable (fn);
6031
6032 return fn;
6033 }
6034 }
6035
6036 /* This function will instantiate the type of the expression given in
6037 RHS to match the type of LHSTYPE. If errors exist, then return
6038 error_mark_node. FLAGS is a bit mask. If TF_ERROR is set, then
6039 we complain on errors. If we are not complaining, never modify rhs,
6040 as overload resolution wants to try many possible instantiations, in
6041 the hope that at least one will work.
6042
6043 For non-recursive calls, LHSTYPE should be a function, pointer to
6044 function, or a pointer to member function. */
6045
6046 tree
instantiate_type(tree lhstype,tree rhs,tsubst_flags_t flags)6047 instantiate_type (tree lhstype, tree rhs, tsubst_flags_t flags)
6048 {
6049 tsubst_flags_t flags_in = flags;
6050 tree access_path = NULL_TREE;
6051
6052 flags &= ~tf_ptrmem_ok;
6053
6054 if (TREE_CODE (lhstype) == UNKNOWN_TYPE)
6055 {
6056 if (flags & tf_error)
6057 error ("not enough type information");
6058 return error_mark_node;
6059 }
6060
6061 if (TREE_TYPE (rhs) != NULL_TREE && ! (type_unknown_p (rhs)))
6062 {
6063 if (same_type_p (lhstype, TREE_TYPE (rhs)))
6064 return rhs;
6065 if (flag_ms_extensions
6066 && TYPE_PTRMEMFUNC_P (lhstype)
6067 && !TYPE_PTRMEMFUNC_P (TREE_TYPE (rhs)))
6068 /* Microsoft allows `A::f' to be resolved to a
6069 pointer-to-member. */
6070 ;
6071 else
6072 {
6073 if (flags & tf_error)
6074 error ("argument of type %qT does not match %qT",
6075 TREE_TYPE (rhs), lhstype);
6076 return error_mark_node;
6077 }
6078 }
6079
6080 if (TREE_CODE (rhs) == BASELINK)
6081 {
6082 access_path = BASELINK_ACCESS_BINFO (rhs);
6083 rhs = BASELINK_FUNCTIONS (rhs);
6084 }
6085
6086 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
6087 deduce any type information. */
6088 if (TREE_CODE (rhs) == NON_DEPENDENT_EXPR)
6089 {
6090 if (flags & tf_error)
6091 error ("not enough type information");
6092 return error_mark_node;
6093 }
6094
6095 /* There only a few kinds of expressions that may have a type
6096 dependent on overload resolution. */
6097 gcc_assert (TREE_CODE (rhs) == ADDR_EXPR
6098 || TREE_CODE (rhs) == COMPONENT_REF
6099 || TREE_CODE (rhs) == COMPOUND_EXPR
6100 || really_overloaded_fn (rhs));
6101
6102 /* We don't overwrite rhs if it is an overloaded function.
6103 Copying it would destroy the tree link. */
6104 if (TREE_CODE (rhs) != OVERLOAD)
6105 rhs = copy_node (rhs);
6106
6107 /* This should really only be used when attempting to distinguish
6108 what sort of a pointer to function we have. For now, any
6109 arithmetic operation which is not supported on pointers
6110 is rejected as an error. */
6111
6112 switch (TREE_CODE (rhs))
6113 {
6114 case COMPONENT_REF:
6115 {
6116 tree member = TREE_OPERAND (rhs, 1);
6117
6118 member = instantiate_type (lhstype, member, flags);
6119 if (member != error_mark_node
6120 && TREE_SIDE_EFFECTS (TREE_OPERAND (rhs, 0)))
6121 /* Do not lose object's side effects. */
6122 return build2 (COMPOUND_EXPR, TREE_TYPE (member),
6123 TREE_OPERAND (rhs, 0), member);
6124 return member;
6125 }
6126
6127 case OFFSET_REF:
6128 rhs = TREE_OPERAND (rhs, 1);
6129 if (BASELINK_P (rhs))
6130 return instantiate_type (lhstype, rhs, flags_in);
6131
6132 /* This can happen if we are forming a pointer-to-member for a
6133 member template. */
6134 gcc_assert (TREE_CODE (rhs) == TEMPLATE_ID_EXPR);
6135
6136 /* Fall through. */
6137
6138 case TEMPLATE_ID_EXPR:
6139 {
6140 tree fns = TREE_OPERAND (rhs, 0);
6141 tree args = TREE_OPERAND (rhs, 1);
6142
6143 return
6144 resolve_address_of_overloaded_function (lhstype, fns, flags_in,
6145 /*template_only=*/true,
6146 args, access_path);
6147 }
6148
6149 case OVERLOAD:
6150 case FUNCTION_DECL:
6151 return
6152 resolve_address_of_overloaded_function (lhstype, rhs, flags_in,
6153 /*template_only=*/false,
6154 /*explicit_targs=*/NULL_TREE,
6155 access_path);
6156
6157 case COMPOUND_EXPR:
6158 TREE_OPERAND (rhs, 0)
6159 = instantiate_type (lhstype, TREE_OPERAND (rhs, 0), flags);
6160 if (TREE_OPERAND (rhs, 0) == error_mark_node)
6161 return error_mark_node;
6162 TREE_OPERAND (rhs, 1)
6163 = instantiate_type (lhstype, TREE_OPERAND (rhs, 1), flags);
6164 if (TREE_OPERAND (rhs, 1) == error_mark_node)
6165 return error_mark_node;
6166
6167 TREE_TYPE (rhs) = lhstype;
6168 return rhs;
6169
6170 case ADDR_EXPR:
6171 {
6172 if (PTRMEM_OK_P (rhs))
6173 flags |= tf_ptrmem_ok;
6174
6175 return instantiate_type (lhstype, TREE_OPERAND (rhs, 0), flags);
6176 }
6177
6178 case ERROR_MARK:
6179 return error_mark_node;
6180
6181 default:
6182 gcc_unreachable ();
6183 }
6184 return error_mark_node;
6185 }
6186
6187 /* Return the name of the virtual function pointer field
6188 (as an IDENTIFIER_NODE) for the given TYPE. Note that
6189 this may have to look back through base types to find the
6190 ultimate field name. (For single inheritance, these could
6191 all be the same name. Who knows for multiple inheritance). */
6192
6193 static tree
get_vfield_name(tree type)6194 get_vfield_name (tree type)
6195 {
6196 tree binfo, base_binfo;
6197 char *buf;
6198
6199 for (binfo = TYPE_BINFO (type);
6200 BINFO_N_BASE_BINFOS (binfo);
6201 binfo = base_binfo)
6202 {
6203 base_binfo = BINFO_BASE_BINFO (binfo, 0);
6204
6205 if (BINFO_VIRTUAL_P (base_binfo)
6206 || !TYPE_CONTAINS_VPTR_P (BINFO_TYPE (base_binfo)))
6207 break;
6208 }
6209
6210 type = BINFO_TYPE (binfo);
6211 buf = (char *) alloca (sizeof (VFIELD_NAME_FORMAT)
6212 + TYPE_NAME_LENGTH (type) + 2);
6213 sprintf (buf, VFIELD_NAME_FORMAT,
6214 IDENTIFIER_POINTER (constructor_name (type)));
6215 return get_identifier (buf);
6216 }
6217
6218 void
print_class_statistics(void)6219 print_class_statistics (void)
6220 {
6221 #ifdef GATHER_STATISTICS
6222 fprintf (stderr, "convert_harshness = %d\n", n_convert_harshness);
6223 fprintf (stderr, "compute_conversion_costs = %d\n", n_compute_conversion_costs);
6224 if (n_vtables)
6225 {
6226 fprintf (stderr, "vtables = %d; vtable searches = %d\n",
6227 n_vtables, n_vtable_searches);
6228 fprintf (stderr, "vtable entries = %d; vtable elems = %d\n",
6229 n_vtable_entries, n_vtable_elems);
6230 }
6231 #endif
6232 }
6233
6234 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
6235 according to [class]:
6236 The class-name is also inserted
6237 into the scope of the class itself. For purposes of access checking,
6238 the inserted class name is treated as if it were a public member name. */
6239
6240 void
build_self_reference(void)6241 build_self_reference (void)
6242 {
6243 tree name = constructor_name (current_class_type);
6244 tree value = build_lang_decl (TYPE_DECL, name, current_class_type);
6245 tree saved_cas;
6246
6247 DECL_NONLOCAL (value) = 1;
6248 DECL_CONTEXT (value) = current_class_type;
6249 DECL_ARTIFICIAL (value) = 1;
6250 SET_DECL_SELF_REFERENCE_P (value);
6251
6252 if (processing_template_decl)
6253 value = push_template_decl (value);
6254
6255 saved_cas = current_access_specifier;
6256 current_access_specifier = access_public_node;
6257 finish_member_declaration (value);
6258 current_access_specifier = saved_cas;
6259 }
6260
6261 /* Returns 1 if TYPE contains only padding bytes. */
6262
6263 int
is_empty_class(tree type)6264 is_empty_class (tree type)
6265 {
6266 if (type == error_mark_node)
6267 return 0;
6268
6269 if (! IS_AGGR_TYPE (type))
6270 return 0;
6271
6272 /* In G++ 3.2, whether or not a class was empty was determined by
6273 looking at its size. */
6274 if (abi_version_at_least (2))
6275 return CLASSTYPE_EMPTY_P (type);
6276 else
6277 return integer_zerop (CLASSTYPE_SIZE (type));
6278 }
6279
6280 /* Returns true if TYPE contains an empty class. */
6281
6282 static bool
contains_empty_class_p(tree type)6283 contains_empty_class_p (tree type)
6284 {
6285 if (is_empty_class (type))
6286 return true;
6287 if (CLASS_TYPE_P (type))
6288 {
6289 tree field;
6290 tree binfo;
6291 tree base_binfo;
6292 int i;
6293
6294 for (binfo = TYPE_BINFO (type), i = 0;
6295 BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
6296 if (contains_empty_class_p (BINFO_TYPE (base_binfo)))
6297 return true;
6298 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
6299 if (TREE_CODE (field) == FIELD_DECL
6300 && !DECL_ARTIFICIAL (field)
6301 && is_empty_class (TREE_TYPE (field)))
6302 return true;
6303 }
6304 else if (TREE_CODE (type) == ARRAY_TYPE)
6305 return contains_empty_class_p (TREE_TYPE (type));
6306 return false;
6307 }
6308
6309 /* Note that NAME was looked up while the current class was being
6310 defined and that the result of that lookup was DECL. */
6311
6312 void
maybe_note_name_used_in_class(tree name,tree decl)6313 maybe_note_name_used_in_class (tree name, tree decl)
6314 {
6315 splay_tree names_used;
6316
6317 /* If we're not defining a class, there's nothing to do. */
6318 if (!(innermost_scope_kind() == sk_class
6319 && TYPE_BEING_DEFINED (current_class_type)))
6320 return;
6321
6322 /* If there's already a binding for this NAME, then we don't have
6323 anything to worry about. */
6324 if (lookup_member (current_class_type, name,
6325 /*protect=*/0, /*want_type=*/false))
6326 return;
6327
6328 if (!current_class_stack[current_class_depth - 1].names_used)
6329 current_class_stack[current_class_depth - 1].names_used
6330 = splay_tree_new (splay_tree_compare_pointers, 0, 0);
6331 names_used = current_class_stack[current_class_depth - 1].names_used;
6332
6333 splay_tree_insert (names_used,
6334 (splay_tree_key) name,
6335 (splay_tree_value) decl);
6336 }
6337
6338 /* Note that NAME was declared (as DECL) in the current class. Check
6339 to see that the declaration is valid. */
6340
6341 void
note_name_declared_in_class(tree name,tree decl)6342 note_name_declared_in_class (tree name, tree decl)
6343 {
6344 splay_tree names_used;
6345 splay_tree_node n;
6346
6347 /* Look to see if we ever used this name. */
6348 names_used
6349 = current_class_stack[current_class_depth - 1].names_used;
6350 if (!names_used)
6351 return;
6352
6353 n = splay_tree_lookup (names_used, (splay_tree_key) name);
6354 if (n)
6355 {
6356 /* [basic.scope.class]
6357
6358 A name N used in a class S shall refer to the same declaration
6359 in its context and when re-evaluated in the completed scope of
6360 S. */
6361 error ("declaration of %q#D", decl);
6362 error ("changes meaning of %qD from %q+#D",
6363 DECL_NAME (OVL_CURRENT (decl)), (tree) n->value);
6364 }
6365 }
6366
6367 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
6368 Secondary vtables are merged with primary vtables; this function
6369 will return the VAR_DECL for the primary vtable. */
6370
6371 tree
get_vtbl_decl_for_binfo(tree binfo)6372 get_vtbl_decl_for_binfo (tree binfo)
6373 {
6374 tree decl;
6375
6376 decl = BINFO_VTABLE (binfo);
6377 if (decl && TREE_CODE (decl) == PLUS_EXPR)
6378 {
6379 gcc_assert (TREE_CODE (TREE_OPERAND (decl, 0)) == ADDR_EXPR);
6380 decl = TREE_OPERAND (TREE_OPERAND (decl, 0), 0);
6381 }
6382 if (decl)
6383 gcc_assert (TREE_CODE (decl) == VAR_DECL);
6384 return decl;
6385 }
6386
6387
6388 /* Returns the binfo for the primary base of BINFO. If the resulting
6389 BINFO is a virtual base, and it is inherited elsewhere in the
6390 hierarchy, then the returned binfo might not be the primary base of
6391 BINFO in the complete object. Check BINFO_PRIMARY_P or
6392 BINFO_LOST_PRIMARY_P to be sure. */
6393
6394 static tree
get_primary_binfo(tree binfo)6395 get_primary_binfo (tree binfo)
6396 {
6397 tree primary_base;
6398
6399 primary_base = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (binfo));
6400 if (!primary_base)
6401 return NULL_TREE;
6402
6403 return copied_binfo (primary_base, binfo);
6404 }
6405
6406 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
6407
6408 static int
maybe_indent_hierarchy(FILE * stream,int indent,int indented_p)6409 maybe_indent_hierarchy (FILE * stream, int indent, int indented_p)
6410 {
6411 if (!indented_p)
6412 fprintf (stream, "%*s", indent, "");
6413 return 1;
6414 }
6415
6416 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
6417 INDENT should be zero when called from the top level; it is
6418 incremented recursively. IGO indicates the next expected BINFO in
6419 inheritance graph ordering. */
6420
6421 static tree
dump_class_hierarchy_r(FILE * stream,int flags,tree binfo,tree igo,int indent)6422 dump_class_hierarchy_r (FILE *stream,
6423 int flags,
6424 tree binfo,
6425 tree igo,
6426 int indent)
6427 {
6428 int indented = 0;
6429 tree base_binfo;
6430 int i;
6431
6432 indented = maybe_indent_hierarchy (stream, indent, 0);
6433 fprintf (stream, "%s (0x%lx) ",
6434 type_as_string (BINFO_TYPE (binfo), TFF_PLAIN_IDENTIFIER),
6435 (unsigned long) binfo);
6436 if (binfo != igo)
6437 {
6438 fprintf (stream, "alternative-path\n");
6439 return igo;
6440 }
6441 igo = TREE_CHAIN (binfo);
6442
6443 fprintf (stream, HOST_WIDE_INT_PRINT_DEC,
6444 tree_low_cst (BINFO_OFFSET (binfo), 0));
6445 if (is_empty_class (BINFO_TYPE (binfo)))
6446 fprintf (stream, " empty");
6447 else if (CLASSTYPE_NEARLY_EMPTY_P (BINFO_TYPE (binfo)))
6448 fprintf (stream, " nearly-empty");
6449 if (BINFO_VIRTUAL_P (binfo))
6450 fprintf (stream, " virtual");
6451 fprintf (stream, "\n");
6452
6453 indented = 0;
6454 if (BINFO_PRIMARY_P (binfo))
6455 {
6456 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6457 fprintf (stream, " primary-for %s (0x%lx)",
6458 type_as_string (BINFO_TYPE (BINFO_INHERITANCE_CHAIN (binfo)),
6459 TFF_PLAIN_IDENTIFIER),
6460 (unsigned long)BINFO_INHERITANCE_CHAIN (binfo));
6461 }
6462 if (BINFO_LOST_PRIMARY_P (binfo))
6463 {
6464 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6465 fprintf (stream, " lost-primary");
6466 }
6467 if (indented)
6468 fprintf (stream, "\n");
6469
6470 if (!(flags & TDF_SLIM))
6471 {
6472 int indented = 0;
6473
6474 if (BINFO_SUBVTT_INDEX (binfo))
6475 {
6476 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6477 fprintf (stream, " subvttidx=%s",
6478 expr_as_string (BINFO_SUBVTT_INDEX (binfo),
6479 TFF_PLAIN_IDENTIFIER));
6480 }
6481 if (BINFO_VPTR_INDEX (binfo))
6482 {
6483 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6484 fprintf (stream, " vptridx=%s",
6485 expr_as_string (BINFO_VPTR_INDEX (binfo),
6486 TFF_PLAIN_IDENTIFIER));
6487 }
6488 if (BINFO_VPTR_FIELD (binfo))
6489 {
6490 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6491 fprintf (stream, " vbaseoffset=%s",
6492 expr_as_string (BINFO_VPTR_FIELD (binfo),
6493 TFF_PLAIN_IDENTIFIER));
6494 }
6495 if (BINFO_VTABLE (binfo))
6496 {
6497 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
6498 fprintf (stream, " vptr=%s",
6499 expr_as_string (BINFO_VTABLE (binfo),
6500 TFF_PLAIN_IDENTIFIER));
6501 }
6502
6503 if (indented)
6504 fprintf (stream, "\n");
6505 }
6506
6507 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
6508 igo = dump_class_hierarchy_r (stream, flags, base_binfo, igo, indent + 2);
6509
6510 return igo;
6511 }
6512
6513 /* Dump the BINFO hierarchy for T. */
6514
6515 static void
dump_class_hierarchy_1(FILE * stream,int flags,tree t)6516 dump_class_hierarchy_1 (FILE *stream, int flags, tree t)
6517 {
6518 fprintf (stream, "Class %s\n", type_as_string (t, TFF_PLAIN_IDENTIFIER));
6519 fprintf (stream, " size=%lu align=%lu\n",
6520 (unsigned long)(tree_low_cst (TYPE_SIZE (t), 0) / BITS_PER_UNIT),
6521 (unsigned long)(TYPE_ALIGN (t) / BITS_PER_UNIT));
6522 fprintf (stream, " base size=%lu base align=%lu\n",
6523 (unsigned long)(tree_low_cst (TYPE_SIZE (CLASSTYPE_AS_BASE (t)), 0)
6524 / BITS_PER_UNIT),
6525 (unsigned long)(TYPE_ALIGN (CLASSTYPE_AS_BASE (t))
6526 / BITS_PER_UNIT));
6527 dump_class_hierarchy_r (stream, flags, TYPE_BINFO (t), TYPE_BINFO (t), 0);
6528 fprintf (stream, "\n");
6529 }
6530
6531 /* Debug interface to hierarchy dumping. */
6532
6533 void
debug_class(tree t)6534 debug_class (tree t)
6535 {
6536 dump_class_hierarchy_1 (stderr, TDF_SLIM, t);
6537 }
6538
6539 static void
dump_class_hierarchy(tree t)6540 dump_class_hierarchy (tree t)
6541 {
6542 int flags;
6543 FILE *stream = dump_begin (TDI_class, &flags);
6544
6545 if (stream)
6546 {
6547 dump_class_hierarchy_1 (stream, flags, t);
6548 dump_end (TDI_class, stream);
6549 }
6550 }
6551
6552 static void
dump_array(FILE * stream,tree decl)6553 dump_array (FILE * stream, tree decl)
6554 {
6555 tree value;
6556 unsigned HOST_WIDE_INT ix;
6557 HOST_WIDE_INT elt;
6558 tree size = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (decl)));
6559
6560 elt = (tree_low_cst (TYPE_SIZE (TREE_TYPE (TREE_TYPE (decl))), 0)
6561 / BITS_PER_UNIT);
6562 fprintf (stream, "%s:", decl_as_string (decl, TFF_PLAIN_IDENTIFIER));
6563 fprintf (stream, " %s entries",
6564 expr_as_string (size_binop (PLUS_EXPR, size, size_one_node),
6565 TFF_PLAIN_IDENTIFIER));
6566 fprintf (stream, "\n");
6567
6568 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (DECL_INITIAL (decl)),
6569 ix, value)
6570 fprintf (stream, "%-4ld %s\n", (long)(ix * elt),
6571 expr_as_string (value, TFF_PLAIN_IDENTIFIER));
6572 }
6573
6574 static void
dump_vtable(tree t,tree binfo,tree vtable)6575 dump_vtable (tree t, tree binfo, tree vtable)
6576 {
6577 int flags;
6578 FILE *stream = dump_begin (TDI_class, &flags);
6579
6580 if (!stream)
6581 return;
6582
6583 if (!(flags & TDF_SLIM))
6584 {
6585 int ctor_vtbl_p = TYPE_BINFO (t) != binfo;
6586
6587 fprintf (stream, "%s for %s",
6588 ctor_vtbl_p ? "Construction vtable" : "Vtable",
6589 type_as_string (BINFO_TYPE (binfo), TFF_PLAIN_IDENTIFIER));
6590 if (ctor_vtbl_p)
6591 {
6592 if (!BINFO_VIRTUAL_P (binfo))
6593 fprintf (stream, " (0x%lx instance)", (unsigned long)binfo);
6594 fprintf (stream, " in %s", type_as_string (t, TFF_PLAIN_IDENTIFIER));
6595 }
6596 fprintf (stream, "\n");
6597 dump_array (stream, vtable);
6598 fprintf (stream, "\n");
6599 }
6600
6601 dump_end (TDI_class, stream);
6602 }
6603
6604 static void
dump_vtt(tree t,tree vtt)6605 dump_vtt (tree t, tree vtt)
6606 {
6607 int flags;
6608 FILE *stream = dump_begin (TDI_class, &flags);
6609
6610 if (!stream)
6611 return;
6612
6613 if (!(flags & TDF_SLIM))
6614 {
6615 fprintf (stream, "VTT for %s\n",
6616 type_as_string (t, TFF_PLAIN_IDENTIFIER));
6617 dump_array (stream, vtt);
6618 fprintf (stream, "\n");
6619 }
6620
6621 dump_end (TDI_class, stream);
6622 }
6623
6624 /* Dump a function or thunk and its thunkees. */
6625
6626 static void
dump_thunk(FILE * stream,int indent,tree thunk)6627 dump_thunk (FILE *stream, int indent, tree thunk)
6628 {
6629 static const char spaces[] = " ";
6630 tree name = DECL_NAME (thunk);
6631 tree thunks;
6632
6633 fprintf (stream, "%.*s%p %s %s", indent, spaces,
6634 (void *)thunk,
6635 !DECL_THUNK_P (thunk) ? "function"
6636 : DECL_THIS_THUNK_P (thunk) ? "this-thunk" : "covariant-thunk",
6637 name ? IDENTIFIER_POINTER (name) : "<unset>");
6638 if (DECL_THUNK_P (thunk))
6639 {
6640 HOST_WIDE_INT fixed_adjust = THUNK_FIXED_OFFSET (thunk);
6641 tree virtual_adjust = THUNK_VIRTUAL_OFFSET (thunk);
6642
6643 fprintf (stream, " fixed=" HOST_WIDE_INT_PRINT_DEC, fixed_adjust);
6644 if (!virtual_adjust)
6645 /*NOP*/;
6646 else if (DECL_THIS_THUNK_P (thunk))
6647 fprintf (stream, " vcall=" HOST_WIDE_INT_PRINT_DEC,
6648 tree_low_cst (virtual_adjust, 0));
6649 else
6650 fprintf (stream, " vbase=" HOST_WIDE_INT_PRINT_DEC "(%s)",
6651 tree_low_cst (BINFO_VPTR_FIELD (virtual_adjust), 0),
6652 type_as_string (BINFO_TYPE (virtual_adjust), TFF_SCOPE));
6653 if (THUNK_ALIAS (thunk))
6654 fprintf (stream, " alias to %p", (void *)THUNK_ALIAS (thunk));
6655 }
6656 fprintf (stream, "\n");
6657 for (thunks = DECL_THUNKS (thunk); thunks; thunks = TREE_CHAIN (thunks))
6658 dump_thunk (stream, indent + 2, thunks);
6659 }
6660
6661 /* Dump the thunks for FN. */
6662
6663 void
debug_thunks(tree fn)6664 debug_thunks (tree fn)
6665 {
6666 dump_thunk (stderr, 0, fn);
6667 }
6668
6669 /* Virtual function table initialization. */
6670
6671 /* Create all the necessary vtables for T and its base classes. */
6672
6673 static void
finish_vtbls(tree t)6674 finish_vtbls (tree t)
6675 {
6676 tree list;
6677 tree vbase;
6678
6679 /* We lay out the primary and secondary vtables in one contiguous
6680 vtable. The primary vtable is first, followed by the non-virtual
6681 secondary vtables in inheritance graph order. */
6682 list = build_tree_list (BINFO_VTABLE (TYPE_BINFO (t)), NULL_TREE);
6683 accumulate_vtbl_inits (TYPE_BINFO (t), TYPE_BINFO (t),
6684 TYPE_BINFO (t), t, list);
6685
6686 /* Then come the virtual bases, also in inheritance graph order. */
6687 for (vbase = TYPE_BINFO (t); vbase; vbase = TREE_CHAIN (vbase))
6688 {
6689 if (!BINFO_VIRTUAL_P (vbase))
6690 continue;
6691 accumulate_vtbl_inits (vbase, vbase, TYPE_BINFO (t), t, list);
6692 }
6693
6694 if (BINFO_VTABLE (TYPE_BINFO (t)))
6695 initialize_vtable (TYPE_BINFO (t), TREE_VALUE (list));
6696 }
6697
6698 /* Initialize the vtable for BINFO with the INITS. */
6699
6700 static void
initialize_vtable(tree binfo,tree inits)6701 initialize_vtable (tree binfo, tree inits)
6702 {
6703 tree decl;
6704
6705 layout_vtable_decl (binfo, list_length (inits));
6706 decl = get_vtbl_decl_for_binfo (binfo);
6707 initialize_artificial_var (decl, inits);
6708 dump_vtable (BINFO_TYPE (binfo), binfo, decl);
6709 }
6710
6711 /* Build the VTT (virtual table table) for T.
6712 A class requires a VTT if it has virtual bases.
6713
6714 This holds
6715 1 - primary virtual pointer for complete object T
6716 2 - secondary VTTs for each direct non-virtual base of T which requires a
6717 VTT
6718 3 - secondary virtual pointers for each direct or indirect base of T which
6719 has virtual bases or is reachable via a virtual path from T.
6720 4 - secondary VTTs for each direct or indirect virtual base of T.
6721
6722 Secondary VTTs look like complete object VTTs without part 4. */
6723
6724 static void
build_vtt(tree t)6725 build_vtt (tree t)
6726 {
6727 tree inits;
6728 tree type;
6729 tree vtt;
6730 tree index;
6731
6732 /* Build up the initializers for the VTT. */
6733 inits = NULL_TREE;
6734 index = size_zero_node;
6735 build_vtt_inits (TYPE_BINFO (t), t, &inits, &index);
6736
6737 /* If we didn't need a VTT, we're done. */
6738 if (!inits)
6739 return;
6740
6741 /* Figure out the type of the VTT. */
6742 type = build_index_type (size_int (list_length (inits) - 1));
6743 type = build_cplus_array_type (const_ptr_type_node, type);
6744
6745 /* Now, build the VTT object itself. */
6746 vtt = build_vtable (t, mangle_vtt_for_type (t), type);
6747 initialize_artificial_var (vtt, inits);
6748 /* Add the VTT to the vtables list. */
6749 TREE_CHAIN (vtt) = TREE_CHAIN (CLASSTYPE_VTABLES (t));
6750 TREE_CHAIN (CLASSTYPE_VTABLES (t)) = vtt;
6751
6752 dump_vtt (t, vtt);
6753 }
6754
6755 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
6756 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
6757 and CHAIN the vtable pointer for this binfo after construction is
6758 complete. VALUE can also be another BINFO, in which case we recurse. */
6759
6760 static tree
binfo_ctor_vtable(tree binfo)6761 binfo_ctor_vtable (tree binfo)
6762 {
6763 tree vt;
6764
6765 while (1)
6766 {
6767 vt = BINFO_VTABLE (binfo);
6768 if (TREE_CODE (vt) == TREE_LIST)
6769 vt = TREE_VALUE (vt);
6770 if (TREE_CODE (vt) == TREE_BINFO)
6771 binfo = vt;
6772 else
6773 break;
6774 }
6775
6776 return vt;
6777 }
6778
6779 /* Data for secondary VTT initialization. */
6780 typedef struct secondary_vptr_vtt_init_data_s
6781 {
6782 /* Is this the primary VTT? */
6783 bool top_level_p;
6784
6785 /* Current index into the VTT. */
6786 tree index;
6787
6788 /* TREE_LIST of initializers built up. */
6789 tree inits;
6790
6791 /* The type being constructed by this secondary VTT. */
6792 tree type_being_constructed;
6793 } secondary_vptr_vtt_init_data;
6794
6795 /* Recursively build the VTT-initializer for BINFO (which is in the
6796 hierarchy dominated by T). INITS points to the end of the initializer
6797 list to date. INDEX is the VTT index where the next element will be
6798 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
6799 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
6800 for virtual bases of T. When it is not so, we build the constructor
6801 vtables for the BINFO-in-T variant. */
6802
6803 static tree *
build_vtt_inits(tree binfo,tree t,tree * inits,tree * index)6804 build_vtt_inits (tree binfo, tree t, tree *inits, tree *index)
6805 {
6806 int i;
6807 tree b;
6808 tree init;
6809 tree secondary_vptrs;
6810 secondary_vptr_vtt_init_data data;
6811 int top_level_p = SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t);
6812
6813 /* We only need VTTs for subobjects with virtual bases. */
6814 if (!CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo)))
6815 return inits;
6816
6817 /* We need to use a construction vtable if this is not the primary
6818 VTT. */
6819 if (!top_level_p)
6820 {
6821 build_ctor_vtbl_group (binfo, t);
6822
6823 /* Record the offset in the VTT where this sub-VTT can be found. */
6824 BINFO_SUBVTT_INDEX (binfo) = *index;
6825 }
6826
6827 /* Add the address of the primary vtable for the complete object. */
6828 init = binfo_ctor_vtable (binfo);
6829 *inits = build_tree_list (NULL_TREE, init);
6830 inits = &TREE_CHAIN (*inits);
6831 if (top_level_p)
6832 {
6833 gcc_assert (!BINFO_VPTR_INDEX (binfo));
6834 BINFO_VPTR_INDEX (binfo) = *index;
6835 }
6836 *index = size_binop (PLUS_EXPR, *index, TYPE_SIZE_UNIT (ptr_type_node));
6837
6838 /* Recursively add the secondary VTTs for non-virtual bases. */
6839 for (i = 0; BINFO_BASE_ITERATE (binfo, i, b); ++i)
6840 if (!BINFO_VIRTUAL_P (b))
6841 inits = build_vtt_inits (b, t, inits, index);
6842
6843 /* Add secondary virtual pointers for all subobjects of BINFO with
6844 either virtual bases or reachable along a virtual path, except
6845 subobjects that are non-virtual primary bases. */
6846 data.top_level_p = top_level_p;
6847 data.index = *index;
6848 data.inits = NULL;
6849 data.type_being_constructed = BINFO_TYPE (binfo);
6850
6851 dfs_walk_once (binfo, dfs_build_secondary_vptr_vtt_inits, NULL, &data);
6852
6853 *index = data.index;
6854
6855 /* The secondary vptrs come back in reverse order. After we reverse
6856 them, and add the INITS, the last init will be the first element
6857 of the chain. */
6858 secondary_vptrs = data.inits;
6859 if (secondary_vptrs)
6860 {
6861 *inits = nreverse (secondary_vptrs);
6862 inits = &TREE_CHAIN (secondary_vptrs);
6863 gcc_assert (*inits == NULL_TREE);
6864 }
6865
6866 if (top_level_p)
6867 /* Add the secondary VTTs for virtual bases in inheritance graph
6868 order. */
6869 for (b = TYPE_BINFO (BINFO_TYPE (binfo)); b; b = TREE_CHAIN (b))
6870 {
6871 if (!BINFO_VIRTUAL_P (b))
6872 continue;
6873
6874 inits = build_vtt_inits (b, t, inits, index);
6875 }
6876 else
6877 /* Remove the ctor vtables we created. */
6878 dfs_walk_all (binfo, dfs_fixup_binfo_vtbls, NULL, binfo);
6879
6880 return inits;
6881 }
6882
6883 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
6884 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
6885
6886 static tree
dfs_build_secondary_vptr_vtt_inits(tree binfo,void * data_)6887 dfs_build_secondary_vptr_vtt_inits (tree binfo, void *data_)
6888 {
6889 secondary_vptr_vtt_init_data *data = (secondary_vptr_vtt_init_data *)data_;
6890
6891 /* We don't care about bases that don't have vtables. */
6892 if (!TYPE_VFIELD (BINFO_TYPE (binfo)))
6893 return dfs_skip_bases;
6894
6895 /* We're only interested in proper subobjects of the type being
6896 constructed. */
6897 if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), data->type_being_constructed))
6898 return NULL_TREE;
6899
6900 /* We're only interested in bases with virtual bases or reachable
6901 via a virtual path from the type being constructed. */
6902 if (!(CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo))
6903 || binfo_via_virtual (binfo, data->type_being_constructed)))
6904 return dfs_skip_bases;
6905
6906 /* We're not interested in non-virtual primary bases. */
6907 if (!BINFO_VIRTUAL_P (binfo) && BINFO_PRIMARY_P (binfo))
6908 return NULL_TREE;
6909
6910 /* Record the index where this secondary vptr can be found. */
6911 if (data->top_level_p)
6912 {
6913 gcc_assert (!BINFO_VPTR_INDEX (binfo));
6914 BINFO_VPTR_INDEX (binfo) = data->index;
6915
6916 if (BINFO_VIRTUAL_P (binfo))
6917 {
6918 /* It's a primary virtual base, and this is not a
6919 construction vtable. Find the base this is primary of in
6920 the inheritance graph, and use that base's vtable
6921 now. */
6922 while (BINFO_PRIMARY_P (binfo))
6923 binfo = BINFO_INHERITANCE_CHAIN (binfo);
6924 }
6925 }
6926
6927 /* Add the initializer for the secondary vptr itself. */
6928 data->inits = tree_cons (NULL_TREE, binfo_ctor_vtable (binfo), data->inits);
6929
6930 /* Advance the vtt index. */
6931 data->index = size_binop (PLUS_EXPR, data->index,
6932 TYPE_SIZE_UNIT (ptr_type_node));
6933
6934 return NULL_TREE;
6935 }
6936
6937 /* Called from build_vtt_inits via dfs_walk. After building
6938 constructor vtables and generating the sub-vtt from them, we need
6939 to restore the BINFO_VTABLES that were scribbled on. DATA is the
6940 binfo of the base whose sub vtt was generated. */
6941
6942 static tree
dfs_fixup_binfo_vtbls(tree binfo,void * data)6943 dfs_fixup_binfo_vtbls (tree binfo, void* data)
6944 {
6945 tree vtable = BINFO_VTABLE (binfo);
6946
6947 if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
6948 /* If this class has no vtable, none of its bases do. */
6949 return dfs_skip_bases;
6950
6951 if (!vtable)
6952 /* This might be a primary base, so have no vtable in this
6953 hierarchy. */
6954 return NULL_TREE;
6955
6956 /* If we scribbled the construction vtable vptr into BINFO, clear it
6957 out now. */
6958 if (TREE_CODE (vtable) == TREE_LIST
6959 && (TREE_PURPOSE (vtable) == (tree) data))
6960 BINFO_VTABLE (binfo) = TREE_CHAIN (vtable);
6961
6962 return NULL_TREE;
6963 }
6964
6965 /* Build the construction vtable group for BINFO which is in the
6966 hierarchy dominated by T. */
6967
6968 static void
build_ctor_vtbl_group(tree binfo,tree t)6969 build_ctor_vtbl_group (tree binfo, tree t)
6970 {
6971 tree list;
6972 tree type;
6973 tree vtbl;
6974 tree inits;
6975 tree id;
6976 tree vbase;
6977
6978 /* See if we've already created this construction vtable group. */
6979 id = mangle_ctor_vtbl_for_type (t, binfo);
6980 if (IDENTIFIER_GLOBAL_VALUE (id))
6981 return;
6982
6983 gcc_assert (!SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t));
6984 /* Build a version of VTBL (with the wrong type) for use in
6985 constructing the addresses of secondary vtables in the
6986 construction vtable group. */
6987 vtbl = build_vtable (t, id, ptr_type_node);
6988 DECL_CONSTRUCTION_VTABLE_P (vtbl) = 1;
6989 list = build_tree_list (vtbl, NULL_TREE);
6990 accumulate_vtbl_inits (binfo, TYPE_BINFO (TREE_TYPE (binfo)),
6991 binfo, t, list);
6992
6993 /* Add the vtables for each of our virtual bases using the vbase in T
6994 binfo. */
6995 for (vbase = TYPE_BINFO (BINFO_TYPE (binfo));
6996 vbase;
6997 vbase = TREE_CHAIN (vbase))
6998 {
6999 tree b;
7000
7001 if (!BINFO_VIRTUAL_P (vbase))
7002 continue;
7003 b = copied_binfo (vbase, binfo);
7004
7005 accumulate_vtbl_inits (b, vbase, binfo, t, list);
7006 }
7007 inits = TREE_VALUE (list);
7008
7009 /* Figure out the type of the construction vtable. */
7010 type = build_index_type (size_int (list_length (inits) - 1));
7011 type = build_cplus_array_type (vtable_entry_type, type);
7012 TREE_TYPE (vtbl) = type;
7013
7014 /* Initialize the construction vtable. */
7015 CLASSTYPE_VTABLES (t) = chainon (CLASSTYPE_VTABLES (t), vtbl);
7016 initialize_artificial_var (vtbl, inits);
7017 dump_vtable (t, binfo, vtbl);
7018 }
7019
7020 /* Add the vtbl initializers for BINFO (and its bases other than
7021 non-virtual primaries) to the list of INITS. BINFO is in the
7022 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
7023 the constructor the vtbl inits should be accumulated for. (If this
7024 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
7025 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
7026 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
7027 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
7028 but are not necessarily the same in terms of layout. */
7029
7030 static void
accumulate_vtbl_inits(tree binfo,tree orig_binfo,tree rtti_binfo,tree t,tree inits)7031 accumulate_vtbl_inits (tree binfo,
7032 tree orig_binfo,
7033 tree rtti_binfo,
7034 tree t,
7035 tree inits)
7036 {
7037 int i;
7038 tree base_binfo;
7039 int ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
7040
7041 gcc_assert (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), BINFO_TYPE (orig_binfo)));
7042
7043 /* If it doesn't have a vptr, we don't do anything. */
7044 if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
7045 return;
7046
7047 /* If we're building a construction vtable, we're not interested in
7048 subobjects that don't require construction vtables. */
7049 if (ctor_vtbl_p
7050 && !CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo))
7051 && !binfo_via_virtual (orig_binfo, BINFO_TYPE (rtti_binfo)))
7052 return;
7053
7054 /* Build the initializers for the BINFO-in-T vtable. */
7055 TREE_VALUE (inits)
7056 = chainon (TREE_VALUE (inits),
7057 dfs_accumulate_vtbl_inits (binfo, orig_binfo,
7058 rtti_binfo, t, inits));
7059
7060 /* Walk the BINFO and its bases. We walk in preorder so that as we
7061 initialize each vtable we can figure out at what offset the
7062 secondary vtable lies from the primary vtable. We can't use
7063 dfs_walk here because we need to iterate through bases of BINFO
7064 and RTTI_BINFO simultaneously. */
7065 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
7066 {
7067 /* Skip virtual bases. */
7068 if (BINFO_VIRTUAL_P (base_binfo))
7069 continue;
7070 accumulate_vtbl_inits (base_binfo,
7071 BINFO_BASE_BINFO (orig_binfo, i),
7072 rtti_binfo, t,
7073 inits);
7074 }
7075 }
7076
7077 /* Called from accumulate_vtbl_inits. Returns the initializers for
7078 the BINFO vtable. */
7079
7080 static tree
dfs_accumulate_vtbl_inits(tree binfo,tree orig_binfo,tree rtti_binfo,tree t,tree l)7081 dfs_accumulate_vtbl_inits (tree binfo,
7082 tree orig_binfo,
7083 tree rtti_binfo,
7084 tree t,
7085 tree l)
7086 {
7087 tree inits = NULL_TREE;
7088 tree vtbl = NULL_TREE;
7089 int ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
7090
7091 if (ctor_vtbl_p
7092 && BINFO_VIRTUAL_P (orig_binfo) && BINFO_PRIMARY_P (orig_binfo))
7093 {
7094 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
7095 primary virtual base. If it is not the same primary in
7096 the hierarchy of T, we'll need to generate a ctor vtable
7097 for it, to place at its location in T. If it is the same
7098 primary, we still need a VTT entry for the vtable, but it
7099 should point to the ctor vtable for the base it is a
7100 primary for within the sub-hierarchy of RTTI_BINFO.
7101
7102 There are three possible cases:
7103
7104 1) We are in the same place.
7105 2) We are a primary base within a lost primary virtual base of
7106 RTTI_BINFO.
7107 3) We are primary to something not a base of RTTI_BINFO. */
7108
7109 tree b;
7110 tree last = NULL_TREE;
7111
7112 /* First, look through the bases we are primary to for RTTI_BINFO
7113 or a virtual base. */
7114 b = binfo;
7115 while (BINFO_PRIMARY_P (b))
7116 {
7117 b = BINFO_INHERITANCE_CHAIN (b);
7118 last = b;
7119 if (BINFO_VIRTUAL_P (b) || b == rtti_binfo)
7120 goto found;
7121 }
7122 /* If we run out of primary links, keep looking down our
7123 inheritance chain; we might be an indirect primary. */
7124 for (b = last; b; b = BINFO_INHERITANCE_CHAIN (b))
7125 if (BINFO_VIRTUAL_P (b) || b == rtti_binfo)
7126 break;
7127 found:
7128
7129 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
7130 base B and it is a base of RTTI_BINFO, this is case 2. In
7131 either case, we share our vtable with LAST, i.e. the
7132 derived-most base within B of which we are a primary. */
7133 if (b == rtti_binfo
7134 || (b && binfo_for_vbase (BINFO_TYPE (b), BINFO_TYPE (rtti_binfo))))
7135 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
7136 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
7137 binfo_ctor_vtable after everything's been set up. */
7138 vtbl = last;
7139
7140 /* Otherwise, this is case 3 and we get our own. */
7141 }
7142 else if (!BINFO_NEW_VTABLE_MARKED (orig_binfo))
7143 return inits;
7144
7145 if (!vtbl)
7146 {
7147 tree index;
7148 int non_fn_entries;
7149
7150 /* Compute the initializer for this vtable. */
7151 inits = build_vtbl_initializer (binfo, orig_binfo, t, rtti_binfo,
7152 &non_fn_entries);
7153
7154 /* Figure out the position to which the VPTR should point. */
7155 vtbl = TREE_PURPOSE (l);
7156 vtbl = build_address (vtbl);
7157 /* ??? We should call fold_convert to convert the address to
7158 vtbl_ptr_type_node, which is the type of elements in the
7159 vtable. However, the resulting NOP_EXPRs confuse other parts
7160 of the C++ front end. */
7161 gcc_assert (TREE_CODE (vtbl) == ADDR_EXPR);
7162 TREE_TYPE (vtbl) = vtbl_ptr_type_node;
7163 index = size_binop (PLUS_EXPR,
7164 size_int (non_fn_entries),
7165 size_int (list_length (TREE_VALUE (l))));
7166 index = size_binop (MULT_EXPR,
7167 TYPE_SIZE_UNIT (vtable_entry_type),
7168 index);
7169 vtbl = build2 (PLUS_EXPR, TREE_TYPE (vtbl), vtbl, index);
7170 }
7171
7172 if (ctor_vtbl_p)
7173 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
7174 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
7175 straighten this out. */
7176 BINFO_VTABLE (binfo) = tree_cons (rtti_binfo, vtbl, BINFO_VTABLE (binfo));
7177 else if (BINFO_PRIMARY_P (binfo) && BINFO_VIRTUAL_P (binfo))
7178 inits = NULL_TREE;
7179 else
7180 /* For an ordinary vtable, set BINFO_VTABLE. */
7181 BINFO_VTABLE (binfo) = vtbl;
7182
7183 return inits;
7184 }
7185
7186 static GTY(()) tree abort_fndecl_addr;
7187
7188 /* Construct the initializer for BINFO's virtual function table. BINFO
7189 is part of the hierarchy dominated by T. If we're building a
7190 construction vtable, the ORIG_BINFO is the binfo we should use to
7191 find the actual function pointers to put in the vtable - but they
7192 can be overridden on the path to most-derived in the graph that
7193 ORIG_BINFO belongs. Otherwise,
7194 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
7195 BINFO that should be indicated by the RTTI information in the
7196 vtable; it will be a base class of T, rather than T itself, if we
7197 are building a construction vtable.
7198
7199 The value returned is a TREE_LIST suitable for wrapping in a
7200 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
7201 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
7202 number of non-function entries in the vtable.
7203
7204 It might seem that this function should never be called with a
7205 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
7206 base is always subsumed by a derived class vtable. However, when
7207 we are building construction vtables, we do build vtables for
7208 primary bases; we need these while the primary base is being
7209 constructed. */
7210
7211 static tree
build_vtbl_initializer(tree binfo,tree orig_binfo,tree t,tree rtti_binfo,int * non_fn_entries_p)7212 build_vtbl_initializer (tree binfo,
7213 tree orig_binfo,
7214 tree t,
7215 tree rtti_binfo,
7216 int* non_fn_entries_p)
7217 {
7218 tree v, b;
7219 tree vfun_inits;
7220 vtbl_init_data vid;
7221 unsigned ix;
7222 tree vbinfo;
7223 VEC(tree,gc) *vbases;
7224
7225 /* Initialize VID. */
7226 memset (&vid, 0, sizeof (vid));
7227 vid.binfo = binfo;
7228 vid.derived = t;
7229 vid.rtti_binfo = rtti_binfo;
7230 vid.last_init = &vid.inits;
7231 vid.primary_vtbl_p = SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t);
7232 vid.ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
7233 vid.generate_vcall_entries = true;
7234 /* The first vbase or vcall offset is at index -3 in the vtable. */
7235 vid.index = ssize_int(-3 * TARGET_VTABLE_DATA_ENTRY_DISTANCE);
7236
7237 /* Add entries to the vtable for RTTI. */
7238 build_rtti_vtbl_entries (binfo, &vid);
7239
7240 /* Create an array for keeping track of the functions we've
7241 processed. When we see multiple functions with the same
7242 signature, we share the vcall offsets. */
7243 vid.fns = VEC_alloc (tree, gc, 32);
7244 /* Add the vcall and vbase offset entries. */
7245 build_vcall_and_vbase_vtbl_entries (binfo, &vid);
7246
7247 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
7248 build_vbase_offset_vtbl_entries. */
7249 for (vbases = CLASSTYPE_VBASECLASSES (t), ix = 0;
7250 VEC_iterate (tree, vbases, ix, vbinfo); ix++)
7251 BINFO_VTABLE_PATH_MARKED (vbinfo) = 0;
7252
7253 /* If the target requires padding between data entries, add that now. */
7254 if (TARGET_VTABLE_DATA_ENTRY_DISTANCE > 1)
7255 {
7256 tree cur, *prev;
7257
7258 for (prev = &vid.inits; (cur = *prev); prev = &TREE_CHAIN (cur))
7259 {
7260 tree add = cur;
7261 int i;
7262
7263 for (i = 1; i < TARGET_VTABLE_DATA_ENTRY_DISTANCE; ++i)
7264 add = tree_cons (NULL_TREE,
7265 build1 (NOP_EXPR, vtable_entry_type,
7266 null_pointer_node),
7267 add);
7268 *prev = add;
7269 }
7270 }
7271
7272 if (non_fn_entries_p)
7273 *non_fn_entries_p = list_length (vid.inits);
7274
7275 /* Go through all the ordinary virtual functions, building up
7276 initializers. */
7277 vfun_inits = NULL_TREE;
7278 for (v = BINFO_VIRTUALS (orig_binfo); v; v = TREE_CHAIN (v))
7279 {
7280 tree delta;
7281 tree vcall_index;
7282 tree fn, fn_original;
7283 tree init = NULL_TREE;
7284
7285 fn = BV_FN (v);
7286 fn_original = fn;
7287 if (DECL_THUNK_P (fn))
7288 {
7289 if (!DECL_NAME (fn))
7290 finish_thunk (fn);
7291 if (THUNK_ALIAS (fn))
7292 {
7293 fn = THUNK_ALIAS (fn);
7294 BV_FN (v) = fn;
7295 }
7296 fn_original = THUNK_TARGET (fn);
7297 }
7298
7299 /* If the only definition of this function signature along our
7300 primary base chain is from a lost primary, this vtable slot will
7301 never be used, so just zero it out. This is important to avoid
7302 requiring extra thunks which cannot be generated with the function.
7303
7304 We first check this in update_vtable_entry_for_fn, so we handle
7305 restored primary bases properly; we also need to do it here so we
7306 zero out unused slots in ctor vtables, rather than filling themff
7307 with erroneous values (though harmless, apart from relocation
7308 costs). */
7309 for (b = binfo; ; b = get_primary_binfo (b))
7310 {
7311 /* We found a defn before a lost primary; go ahead as normal. */
7312 if (look_for_overrides_here (BINFO_TYPE (b), fn_original))
7313 break;
7314
7315 /* The nearest definition is from a lost primary; clear the
7316 slot. */
7317 if (BINFO_LOST_PRIMARY_P (b))
7318 {
7319 init = size_zero_node;
7320 break;
7321 }
7322 }
7323
7324 if (! init)
7325 {
7326 /* Pull the offset for `this', and the function to call, out of
7327 the list. */
7328 delta = BV_DELTA (v);
7329 vcall_index = BV_VCALL_INDEX (v);
7330
7331 gcc_assert (TREE_CODE (delta) == INTEGER_CST);
7332 gcc_assert (TREE_CODE (fn) == FUNCTION_DECL);
7333
7334 /* You can't call an abstract virtual function; it's abstract.
7335 So, we replace these functions with __pure_virtual. */
7336 if (DECL_PURE_VIRTUAL_P (fn_original))
7337 {
7338 fn = abort_fndecl;
7339 if (abort_fndecl_addr == NULL)
7340 abort_fndecl_addr = build1 (ADDR_EXPR, vfunc_ptr_type_node, fn);
7341 init = abort_fndecl_addr;
7342 }
7343 else
7344 {
7345 if (!integer_zerop (delta) || vcall_index)
7346 {
7347 fn = make_thunk (fn, /*this_adjusting=*/1, delta, vcall_index);
7348 if (!DECL_NAME (fn))
7349 finish_thunk (fn);
7350 }
7351 /* Take the address of the function, considering it to be of an
7352 appropriate generic type. */
7353 init = build1 (ADDR_EXPR, vfunc_ptr_type_node, fn);
7354 }
7355 }
7356
7357 /* And add it to the chain of initializers. */
7358 if (TARGET_VTABLE_USES_DESCRIPTORS)
7359 {
7360 int i;
7361 if (init == size_zero_node)
7362 for (i = 0; i < TARGET_VTABLE_USES_DESCRIPTORS; ++i)
7363 vfun_inits = tree_cons (NULL_TREE, init, vfun_inits);
7364 else
7365 for (i = 0; i < TARGET_VTABLE_USES_DESCRIPTORS; ++i)
7366 {
7367 tree fdesc = build2 (FDESC_EXPR, vfunc_ptr_type_node,
7368 TREE_OPERAND (init, 0),
7369 build_int_cst (NULL_TREE, i));
7370 TREE_CONSTANT (fdesc) = 1;
7371 TREE_INVARIANT (fdesc) = 1;
7372
7373 vfun_inits = tree_cons (NULL_TREE, fdesc, vfun_inits);
7374 }
7375 }
7376 else
7377 vfun_inits = tree_cons (NULL_TREE, init, vfun_inits);
7378 }
7379
7380 /* The initializers for virtual functions were built up in reverse
7381 order; straighten them out now. */
7382 vfun_inits = nreverse (vfun_inits);
7383
7384 /* The negative offset initializers are also in reverse order. */
7385 vid.inits = nreverse (vid.inits);
7386
7387 /* Chain the two together. */
7388 return chainon (vid.inits, vfun_inits);
7389 }
7390
7391 /* Adds to vid->inits the initializers for the vbase and vcall
7392 offsets in BINFO, which is in the hierarchy dominated by T. */
7393
7394 static void
build_vcall_and_vbase_vtbl_entries(tree binfo,vtbl_init_data * vid)7395 build_vcall_and_vbase_vtbl_entries (tree binfo, vtbl_init_data* vid)
7396 {
7397 tree b;
7398
7399 /* If this is a derived class, we must first create entries
7400 corresponding to the primary base class. */
7401 b = get_primary_binfo (binfo);
7402 if (b)
7403 build_vcall_and_vbase_vtbl_entries (b, vid);
7404
7405 /* Add the vbase entries for this base. */
7406 build_vbase_offset_vtbl_entries (binfo, vid);
7407 /* Add the vcall entries for this base. */
7408 build_vcall_offset_vtbl_entries (binfo, vid);
7409 }
7410
7411 /* Returns the initializers for the vbase offset entries in the vtable
7412 for BINFO (which is part of the class hierarchy dominated by T), in
7413 reverse order. VBASE_OFFSET_INDEX gives the vtable index
7414 where the next vbase offset will go. */
7415
7416 static void
build_vbase_offset_vtbl_entries(tree binfo,vtbl_init_data * vid)7417 build_vbase_offset_vtbl_entries (tree binfo, vtbl_init_data* vid)
7418 {
7419 tree vbase;
7420 tree t;
7421 tree non_primary_binfo;
7422
7423 /* If there are no virtual baseclasses, then there is nothing to
7424 do. */
7425 if (!CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo)))
7426 return;
7427
7428 t = vid->derived;
7429
7430 /* We might be a primary base class. Go up the inheritance hierarchy
7431 until we find the most derived class of which we are a primary base:
7432 it is the offset of that which we need to use. */
7433 non_primary_binfo = binfo;
7434 while (BINFO_INHERITANCE_CHAIN (non_primary_binfo))
7435 {
7436 tree b;
7437
7438 /* If we have reached a virtual base, then it must be a primary
7439 base (possibly multi-level) of vid->binfo, or we wouldn't
7440 have called build_vcall_and_vbase_vtbl_entries for it. But it
7441 might be a lost primary, so just skip down to vid->binfo. */
7442 if (BINFO_VIRTUAL_P (non_primary_binfo))
7443 {
7444 non_primary_binfo = vid->binfo;
7445 break;
7446 }
7447
7448 b = BINFO_INHERITANCE_CHAIN (non_primary_binfo);
7449 if (get_primary_binfo (b) != non_primary_binfo)
7450 break;
7451 non_primary_binfo = b;
7452 }
7453
7454 /* Go through the virtual bases, adding the offsets. */
7455 for (vbase = TYPE_BINFO (BINFO_TYPE (binfo));
7456 vbase;
7457 vbase = TREE_CHAIN (vbase))
7458 {
7459 tree b;
7460 tree delta;
7461
7462 if (!BINFO_VIRTUAL_P (vbase))
7463 continue;
7464
7465 /* Find the instance of this virtual base in the complete
7466 object. */
7467 b = copied_binfo (vbase, binfo);
7468
7469 /* If we've already got an offset for this virtual base, we
7470 don't need another one. */
7471 if (BINFO_VTABLE_PATH_MARKED (b))
7472 continue;
7473 BINFO_VTABLE_PATH_MARKED (b) = 1;
7474
7475 /* Figure out where we can find this vbase offset. */
7476 delta = size_binop (MULT_EXPR,
7477 vid->index,
7478 convert (ssizetype,
7479 TYPE_SIZE_UNIT (vtable_entry_type)));
7480 if (vid->primary_vtbl_p)
7481 BINFO_VPTR_FIELD (b) = delta;
7482
7483 if (binfo != TYPE_BINFO (t))
7484 /* The vbase offset had better be the same. */
7485 gcc_assert (tree_int_cst_equal (delta, BINFO_VPTR_FIELD (vbase)));
7486
7487 /* The next vbase will come at a more negative offset. */
7488 vid->index = size_binop (MINUS_EXPR, vid->index,
7489 ssize_int (TARGET_VTABLE_DATA_ENTRY_DISTANCE));
7490
7491 /* The initializer is the delta from BINFO to this virtual base.
7492 The vbase offsets go in reverse inheritance-graph order, and
7493 we are walking in inheritance graph order so these end up in
7494 the right order. */
7495 delta = size_diffop (BINFO_OFFSET (b), BINFO_OFFSET (non_primary_binfo));
7496
7497 *vid->last_init
7498 = build_tree_list (NULL_TREE,
7499 fold_build1 (NOP_EXPR,
7500 vtable_entry_type,
7501 delta));
7502 vid->last_init = &TREE_CHAIN (*vid->last_init);
7503 }
7504 }
7505
7506 /* Adds the initializers for the vcall offset entries in the vtable
7507 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
7508 to VID->INITS. */
7509
7510 static void
build_vcall_offset_vtbl_entries(tree binfo,vtbl_init_data * vid)7511 build_vcall_offset_vtbl_entries (tree binfo, vtbl_init_data* vid)
7512 {
7513 /* We only need these entries if this base is a virtual base. We
7514 compute the indices -- but do not add to the vtable -- when
7515 building the main vtable for a class. */
7516 if (BINFO_VIRTUAL_P (binfo) || binfo == TYPE_BINFO (vid->derived))
7517 {
7518 /* We need a vcall offset for each of the virtual functions in this
7519 vtable. For example:
7520
7521 class A { virtual void f (); };
7522 class B1 : virtual public A { virtual void f (); };
7523 class B2 : virtual public A { virtual void f (); };
7524 class C: public B1, public B2 { virtual void f (); };
7525
7526 A C object has a primary base of B1, which has a primary base of A. A
7527 C also has a secondary base of B2, which no longer has a primary base
7528 of A. So the B2-in-C construction vtable needs a secondary vtable for
7529 A, which will adjust the A* to a B2* to call f. We have no way of
7530 knowing what (or even whether) this offset will be when we define B2,
7531 so we store this "vcall offset" in the A sub-vtable and look it up in
7532 a "virtual thunk" for B2::f.
7533
7534 We need entries for all the functions in our primary vtable and
7535 in our non-virtual bases' secondary vtables. */
7536 vid->vbase = binfo;
7537 /* If we are just computing the vcall indices -- but do not need
7538 the actual entries -- not that. */
7539 if (!BINFO_VIRTUAL_P (binfo))
7540 vid->generate_vcall_entries = false;
7541 /* Now, walk through the non-virtual bases, adding vcall offsets. */
7542 add_vcall_offset_vtbl_entries_r (binfo, vid);
7543 }
7544 }
7545
7546 /* Build vcall offsets, starting with those for BINFO. */
7547
7548 static void
add_vcall_offset_vtbl_entries_r(tree binfo,vtbl_init_data * vid)7549 add_vcall_offset_vtbl_entries_r (tree binfo, vtbl_init_data* vid)
7550 {
7551 int i;
7552 tree primary_binfo;
7553 tree base_binfo;
7554
7555 /* Don't walk into virtual bases -- except, of course, for the
7556 virtual base for which we are building vcall offsets. Any
7557 primary virtual base will have already had its offsets generated
7558 through the recursion in build_vcall_and_vbase_vtbl_entries. */
7559 if (BINFO_VIRTUAL_P (binfo) && vid->vbase != binfo)
7560 return;
7561
7562 /* If BINFO has a primary base, process it first. */
7563 primary_binfo = get_primary_binfo (binfo);
7564 if (primary_binfo)
7565 add_vcall_offset_vtbl_entries_r (primary_binfo, vid);
7566
7567 /* Add BINFO itself to the list. */
7568 add_vcall_offset_vtbl_entries_1 (binfo, vid);
7569
7570 /* Scan the non-primary bases of BINFO. */
7571 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
7572 if (base_binfo != primary_binfo)
7573 add_vcall_offset_vtbl_entries_r (base_binfo, vid);
7574 }
7575
7576 /* Called from build_vcall_offset_vtbl_entries_r. */
7577
7578 static void
add_vcall_offset_vtbl_entries_1(tree binfo,vtbl_init_data * vid)7579 add_vcall_offset_vtbl_entries_1 (tree binfo, vtbl_init_data* vid)
7580 {
7581 /* Make entries for the rest of the virtuals. */
7582 if (abi_version_at_least (2))
7583 {
7584 tree orig_fn;
7585
7586 /* The ABI requires that the methods be processed in declaration
7587 order. G++ 3.2 used the order in the vtable. */
7588 for (orig_fn = TYPE_METHODS (BINFO_TYPE (binfo));
7589 orig_fn;
7590 orig_fn = TREE_CHAIN (orig_fn))
7591 if (DECL_VINDEX (orig_fn))
7592 add_vcall_offset (orig_fn, binfo, vid);
7593 }
7594 else
7595 {
7596 tree derived_virtuals;
7597 tree base_virtuals;
7598 tree orig_virtuals;
7599 /* If BINFO is a primary base, the most derived class which has
7600 BINFO as a primary base; otherwise, just BINFO. */
7601 tree non_primary_binfo;
7602
7603 /* We might be a primary base class. Go up the inheritance hierarchy
7604 until we find the most derived class of which we are a primary base:
7605 it is the BINFO_VIRTUALS there that we need to consider. */
7606 non_primary_binfo = binfo;
7607 while (BINFO_INHERITANCE_CHAIN (non_primary_binfo))
7608 {
7609 tree b;
7610
7611 /* If we have reached a virtual base, then it must be vid->vbase,
7612 because we ignore other virtual bases in
7613 add_vcall_offset_vtbl_entries_r. In turn, it must be a primary
7614 base (possibly multi-level) of vid->binfo, or we wouldn't
7615 have called build_vcall_and_vbase_vtbl_entries for it. But it
7616 might be a lost primary, so just skip down to vid->binfo. */
7617 if (BINFO_VIRTUAL_P (non_primary_binfo))
7618 {
7619 gcc_assert (non_primary_binfo == vid->vbase);
7620 non_primary_binfo = vid->binfo;
7621 break;
7622 }
7623
7624 b = BINFO_INHERITANCE_CHAIN (non_primary_binfo);
7625 if (get_primary_binfo (b) != non_primary_binfo)
7626 break;
7627 non_primary_binfo = b;
7628 }
7629
7630 if (vid->ctor_vtbl_p)
7631 /* For a ctor vtable we need the equivalent binfo within the hierarchy
7632 where rtti_binfo is the most derived type. */
7633 non_primary_binfo
7634 = original_binfo (non_primary_binfo, vid->rtti_binfo);
7635
7636 for (base_virtuals = BINFO_VIRTUALS (binfo),
7637 derived_virtuals = BINFO_VIRTUALS (non_primary_binfo),
7638 orig_virtuals = BINFO_VIRTUALS (TYPE_BINFO (BINFO_TYPE (binfo)));
7639 base_virtuals;
7640 base_virtuals = TREE_CHAIN (base_virtuals),
7641 derived_virtuals = TREE_CHAIN (derived_virtuals),
7642 orig_virtuals = TREE_CHAIN (orig_virtuals))
7643 {
7644 tree orig_fn;
7645
7646 /* Find the declaration that originally caused this function to
7647 be present in BINFO_TYPE (binfo). */
7648 orig_fn = BV_FN (orig_virtuals);
7649
7650 /* When processing BINFO, we only want to generate vcall slots for
7651 function slots introduced in BINFO. So don't try to generate
7652 one if the function isn't even defined in BINFO. */
7653 if (!SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), DECL_CONTEXT (orig_fn)))
7654 continue;
7655
7656 add_vcall_offset (orig_fn, binfo, vid);
7657 }
7658 }
7659 }
7660
7661 /* Add a vcall offset entry for ORIG_FN to the vtable. */
7662
7663 static void
add_vcall_offset(tree orig_fn,tree binfo,vtbl_init_data * vid)7664 add_vcall_offset (tree orig_fn, tree binfo, vtbl_init_data *vid)
7665 {
7666 size_t i;
7667 tree vcall_offset;
7668 tree derived_entry;
7669
7670 /* If there is already an entry for a function with the same
7671 signature as FN, then we do not need a second vcall offset.
7672 Check the list of functions already present in the derived
7673 class vtable. */
7674 for (i = 0; VEC_iterate (tree, vid->fns, i, derived_entry); ++i)
7675 {
7676 if (same_signature_p (derived_entry, orig_fn)
7677 /* We only use one vcall offset for virtual destructors,
7678 even though there are two virtual table entries. */
7679 || (DECL_DESTRUCTOR_P (derived_entry)
7680 && DECL_DESTRUCTOR_P (orig_fn)))
7681 return;
7682 }
7683
7684 /* If we are building these vcall offsets as part of building
7685 the vtable for the most derived class, remember the vcall
7686 offset. */
7687 if (vid->binfo == TYPE_BINFO (vid->derived))
7688 {
7689 tree_pair_p elt = VEC_safe_push (tree_pair_s, gc,
7690 CLASSTYPE_VCALL_INDICES (vid->derived),
7691 NULL);
7692 elt->purpose = orig_fn;
7693 elt->value = vid->index;
7694 }
7695
7696 /* The next vcall offset will be found at a more negative
7697 offset. */
7698 vid->index = size_binop (MINUS_EXPR, vid->index,
7699 ssize_int (TARGET_VTABLE_DATA_ENTRY_DISTANCE));
7700
7701 /* Keep track of this function. */
7702 VEC_safe_push (tree, gc, vid->fns, orig_fn);
7703
7704 if (vid->generate_vcall_entries)
7705 {
7706 tree base;
7707 tree fn;
7708
7709 /* Find the overriding function. */
7710 fn = find_final_overrider (vid->rtti_binfo, binfo, orig_fn);
7711 if (fn == error_mark_node)
7712 vcall_offset = build1 (NOP_EXPR, vtable_entry_type,
7713 integer_zero_node);
7714 else
7715 {
7716 base = TREE_VALUE (fn);
7717
7718 /* The vbase we're working on is a primary base of
7719 vid->binfo. But it might be a lost primary, so its
7720 BINFO_OFFSET might be wrong, so we just use the
7721 BINFO_OFFSET from vid->binfo. */
7722 vcall_offset = size_diffop (BINFO_OFFSET (base),
7723 BINFO_OFFSET (vid->binfo));
7724 vcall_offset = fold_build1 (NOP_EXPR, vtable_entry_type,
7725 vcall_offset);
7726 }
7727 /* Add the initializer to the vtable. */
7728 *vid->last_init = build_tree_list (NULL_TREE, vcall_offset);
7729 vid->last_init = &TREE_CHAIN (*vid->last_init);
7730 }
7731 }
7732
7733 /* Return vtbl initializers for the RTTI entries corresponding to the
7734 BINFO's vtable. The RTTI entries should indicate the object given
7735 by VID->rtti_binfo. */
7736
7737 static void
build_rtti_vtbl_entries(tree binfo,vtbl_init_data * vid)7738 build_rtti_vtbl_entries (tree binfo, vtbl_init_data* vid)
7739 {
7740 tree b;
7741 tree t;
7742 tree basetype;
7743 tree offset;
7744 tree decl;
7745 tree init;
7746
7747 basetype = BINFO_TYPE (binfo);
7748 t = BINFO_TYPE (vid->rtti_binfo);
7749
7750 /* To find the complete object, we will first convert to our most
7751 primary base, and then add the offset in the vtbl to that value. */
7752 b = binfo;
7753 while (CLASSTYPE_HAS_PRIMARY_BASE_P (BINFO_TYPE (b))
7754 && !BINFO_LOST_PRIMARY_P (b))
7755 {
7756 tree primary_base;
7757
7758 primary_base = get_primary_binfo (b);
7759 gcc_assert (BINFO_PRIMARY_P (primary_base)
7760 && BINFO_INHERITANCE_CHAIN (primary_base) == b);
7761 b = primary_base;
7762 }
7763 offset = size_diffop (BINFO_OFFSET (vid->rtti_binfo), BINFO_OFFSET (b));
7764
7765 /* The second entry is the address of the typeinfo object. */
7766 if (flag_rtti)
7767 decl = build_address (get_tinfo_decl (t));
7768 else
7769 decl = integer_zero_node;
7770
7771 /* Convert the declaration to a type that can be stored in the
7772 vtable. */
7773 init = build_nop (vfunc_ptr_type_node, decl);
7774 *vid->last_init = build_tree_list (NULL_TREE, init);
7775 vid->last_init = &TREE_CHAIN (*vid->last_init);
7776
7777 /* Add the offset-to-top entry. It comes earlier in the vtable than
7778 the typeinfo entry. Convert the offset to look like a
7779 function pointer, so that we can put it in the vtable. */
7780 init = build_nop (vfunc_ptr_type_node, offset);
7781 *vid->last_init = build_tree_list (NULL_TREE, init);
7782 vid->last_init = &TREE_CHAIN (*vid->last_init);
7783 }
7784
7785 /* Fold a OBJ_TYPE_REF expression to the address of a function.
7786 KNOWN_TYPE carries the true type of OBJ_TYPE_REF_OBJECT(REF). */
7787
7788 tree
cp_fold_obj_type_ref(tree ref,tree known_type)7789 cp_fold_obj_type_ref (tree ref, tree known_type)
7790 {
7791 HOST_WIDE_INT index = tree_low_cst (OBJ_TYPE_REF_TOKEN (ref), 1);
7792 HOST_WIDE_INT i = 0;
7793 tree v = BINFO_VIRTUALS (TYPE_BINFO (known_type));
7794 tree fndecl;
7795
7796 while (i != index)
7797 {
7798 i += (TARGET_VTABLE_USES_DESCRIPTORS
7799 ? TARGET_VTABLE_USES_DESCRIPTORS : 1);
7800 v = TREE_CHAIN (v);
7801 }
7802
7803 fndecl = BV_FN (v);
7804
7805 #ifdef ENABLE_CHECKING
7806 gcc_assert (tree_int_cst_equal (OBJ_TYPE_REF_TOKEN (ref),
7807 DECL_VINDEX (fndecl)));
7808 #endif
7809
7810 cgraph_node (fndecl)->local.vtable_method = true;
7811
7812 return build_address (fndecl);
7813 }
7814
7815 #include "gt-cp-class.h"
7816